Osteoporotic changes, and bone resorption can be a component of aging.
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Resorption is the breakdown of old bones by osteoclasts, a type of bone cell.
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"Denosumab also decreases bone resorption by inhibiting maturation of osteoclasts through binding to a receptor on the surface of 'pre-osteoclast cells,' " McLean said.
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The ones most often prescribed are called bisphosphonates, like Fosamax, Boniva, Reclast and Actonel, that block the resorption of bone by cells called osteoclasts.
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Recommending fewer screenings "Bisphosphonates are medications that have been used for many years that act largely by inhibiting resorption of bone," McLean wrote in an email.
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Loss of teeth is a problem too—resulting not only in less lip and facial tissue support, but accentuating bone resorption of the alveolus (arches of the jaws).
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There is no guarantee the birth will be successful since a condition known as fetal resorption, or Vanishing Twin Syndrome, in which a fetus dies before it is born, is "not uncommon" in pandas, the zoo said.
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According to the zoo, based on hormone tracking, keepers believed Thi Hi Way's pregnancy failed and she went through a "natural resorption process," because she missed her expected due date and began to return to her normal weight.
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If the insult is persistent, then resorption continues, and if the tooth tissue is irretrievably damaged, complete resorption may occur.
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Multiple idiopathic cervical resorption is when a minimum of 3 teeth are affected by cervical resorption for no evident cause.
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Paediatric patients have a higher risk of resorption, with a resorption rate up to 50%. Bone resorption is more likely to occur in this group of patients when their cranioplasty is carried out over 6 weeks from their previous operation. Fragmented bone flaps, as well as large bone flaps (>70 cm2), are associated with a higher resorption rate.
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Osteocyte activity plays a key role in this process. Conditions that result in a decrease in bone mass can either be caused by an increase in resorption or by a decrease in ossification. During childhood, bone formation exceeds resorption. As the aging process occurs, resorption exceeds formation.
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Recently it was shown that A. hedei did have functional teeth that were shed by basal-resorption, something that was overlooked during previous research efforts due to methodological limitations. The location of the resorption cups, places where resorption of the tooth base took place, and newly formed teeth are not perfectly aligned, which suggests a flexible form of tooth replacement. Nonetheless, some form of patterning can be recognised in the teeth. Multiple layers of resorption cups have been found, which means shedding by resorption could take place multiple times.
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Condylar resorption, also called idiopathic condylar resorption, ICR, and condylysis, is a temporomandibular joint disorder in which one or both of the mandibular condyles are broken down in a bone resorption process. This disorder is nine times more likely to be present in females than males, and is more common among teenagers.
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Alendronate inhibits osteoclast-mediated bone-resorption. Like all bisphosphonates, it is chemically related to inorganic pyrophosphate, the endogenous regulator of bone turnover. But while pyrophosphate inhibits both osteoclastic bone resorption and the mineralization of the bone newly formed by osteoblasts, alendronate specifically inhibits bone resorption without any effect on mineralization at pharmacologically achievable doses. Its inhibition of bone-resorption is dose-dependent and approximately 1,000 times stronger than the equimolar effect of the first bisphosphonate drug, etidronate.
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Bone is lost through the process of resorption which involves osteoclasts breaking down the hard tissue of bone. A key indication of resorption is when scalloped erosion occurs. This is also known as Howship’s lacuna. The resorption phase lasts as long as the lifespan of the osteoclast which is around 8 to 10 days.
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After this resorption phase, the osteoclast can continue resorbing surfaces in another cycle or carry out apoptosis. A repair phase follows the resorption phase which lasts over 3 months. In patients with periodontal disease, inflammation lasts longer and during the repair phase, resorption may override any bone formation. This results in a net loss of alveolar bone.
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It may be involved in resorption of water from food.
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Osteoclasts are very large multinucleate cells that are responsible for the breakdown of bones by the process of bone resorption. New bone is then formed by the osteoblasts. Bone is constantly remodelled by the resorption of osteoclasts and created by osteoblasts. Osteoclasts are large cells with multiple nuclei located on bone surfaces in what are called Howship's lacunae (or resorption pits).
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Instead, non-pathological bone resorption, or unknown bone diseases, are suggested as causes.Tanke, D. H, and Farke, A. A. (2006). Bone resorption, bone lesions, and extracranial fenestrae in ceratopsid dinosaurs: a preliminary assessment. in: Carpenter, K. (ed.).
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Fetal resorption in rats is common and can be influenced by antioxidants.
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Docusate might increase resorption of other drugs, for example, dantron (1,8-dihydroxyanthraquinone).
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Angle Orthod. 2002 April;72(2):95-104. Resorption is common, especially amongst females with enlarged dental follicles.Chaushu S, Kaczor- Urbanowicz K, Zadurska M, Becker A. Predisposing factors for severe incisor root resorption associated with impacted maxillary canines.
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Radiographically a radiolucent area within the root canal may be visible and/or the canal may appear sclerosed. Chronic pulpal inflammation is thought to be a cause of internal resorption. The pulp must be vital below the area of resorption to provide osteoclasts with nutrients. If the pulp becomes totally necrosed the resorption will cease unless lateral canals are present to supply osteoclasts with nutrients.
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Queen dominance is correlated with aggressive behaviors. One theory for why these subordinate remain in the nest relates to the possibility for egg resorption (egg resorption gives subordinate queens reason to not leave the nest and start their own).
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In particular, 41Ca has been used to measure bone resorption in postmenopausal women.
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External inflammatory resorption occurs following prolonged insult leading to continuing pathological resorption. It is commonly caused by damage to the periodontal ligament (PDL), drying of root surface following avulsion, exposure of dentine tubules, and pressure. This process can occur rapidly.
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Early diagnosis of maxillary ectopic canines is essential as delayed diagnosis may result in complications such as the resorption of upper incisors. Maxillary ectopic canines can result in the resorption of central incisors in 15% of cases, and lateral incisors in 34% of cases.Ericson, S. Bjerklin, K. Falahat, B. Does the canine dental follicle cause resorption of permanent incisor roots? A computed tomographic study of erupting maxillary canines.
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Osteoclasts are found on those surfaces of bone which are undergoing resorption. On such surfaces, the osteoclasts are seen to be located in shallow depressions called resorption bays (Howship's lacunae). The resorption bays are created by erosive action of osteoclasts on the underlying bone. The border of the lower part of an osteoclast exhibits finger-like processes due to presence of deep infoldings of the cell membrane; this border is called ruffled border.
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Bone resorption is resorption of bone tissue, that is, the process by which osteoclasts break down the tissue in bones and release the minerals, resulting in a transfer of calcium from bone tissue to the blood. The osteoclasts are multi-nucleated cells that contain numerous mitochondria and lysosomes. These are the cells responsible for the resorption of bone. Osteoclasts are generally present on the outer layer of bone, just beneath the periosteum.
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Also known as transient inflammatory resorption. It is a self-limiting process and is a often and incidental radiographic finding. Transient inflammatory resorption undergoes healing and should be monitored only. It is caused by localised and limited injury to root surface or surrounding tissues.
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In 1998, an ultrasound study found that the resorption of one or two conceptuses happen in up to 10% of all dog pregnancies, although many cases of assumed complete resorption of an entire litter are likely to have just been the bitch experiencing a pseudopregnancy.
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Cranioplasty is a risky operation, with potential risks such as bacterial infection and bone flap resorption.
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The above four cases of trauma, tumor, resorption, and ankylosis represent the indications of alloplastic prosthesis.
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Adrenalone passes into breast milk, but adverse effects are unlikely because of its very low systemic resorption.
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Certain animal immune-derived cells may form aggregate cells, such as the osteoclast cells responsible for bone resorption.
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Treatment for TRs is limited to tooth extraction because the lesion is progressive. Amputation of the tooth crown without root removal has also been advocated in cases demonstrated on a radiograph to be type 2 resorption without associated periodontal or endodontic disease because the roots are being replaced by bone. However, X-rays are recommended prior to this treatment to document root resorption and lack of the periodontal ligament. Tooth restoration is not recommended because resorption of the tooth will continue underneath the restoration.
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Tooth resorption, or root resorption, is the progressive loss of dentine and cementum by the action of osteoclasts. This is a normal physiological process in the exfoliation of the primary dentition, caused by osteoclast differentiation due to pressure exerted by the erupting permanent tooth. However, in the secondary dentition the process is pathological.
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Pulp necrosis, trauma, periodontal treatment, orthodontics and tooth whitening are the most common stimulants of inflammatory resorption. Some other less common causes include pressure from ectopic teeth, cysts, and tumours. These cause damage to the periodontal ligament (PDL), cementum, or pre-dentine. These tissues provide protection from resorption when intact and healthy.
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Tartrate-resistant acid phosphatase may be used as a biochemical marker of osteoclast function during the process of bone resorption.
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Light micrograph of an osteoclast displaying typical distinguishing characteristics: a large cell with multiple nuclei and a "foamy" cytosol. Osteoclasts are located on the surface of bones and form resorption pits by excreting H+ to the bone surface removing hydroxyapatite, multiple bone minerals, and organic components: collagen and dentin. The purpose of bone resorption is to release calcium to the blood stream for various life processes. These resorption pits are visible under electron microscopy and distinctive trails are formed from prolonged resorption. Osteoclasts have shown to be “absolutely dependent on extracellular acidification”. A drop in pH of <0.1 units can cause a 100% increase in osteoclast cell activity, this effect persists with prolonged acidosis with no desensitization, “amplifying the effects of modest pH differences”.
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The cause of condylar resorption is unknown, but there are theories. Because condylar resorption is much more likely to occur in young females, hormonal mediation may be involved. Strain on the temporomandibular joint from orthodontics or orthognathic surgery may be related to the condition. Reactive arthritis, rheumatoid arthritis, and psoriatic arthritis are other possible causes.
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Therefore RANKL can more readily bind to RANK and cause the increased osteoclastogenesis and bone resorption seen in osteoporosis. Decreased estrogen is a common cause of osteoporosis that can be seen in other conditions such as ovariectomy, ovarian failure, anorexia, and hyperprolactinaemia. Osteoblastic synthesis of bone does not increase to compensate for the accelerated bone resorption as the lower estrogen levels result in increased rates of osteoblast apoptosis. The higher rate of bone resorption compared to bone formation leads to the increased porosity and low bone mineral density of individuals with osteoporosis.
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Prostaglandins, specifically PGE2 and PGI2, are important in inflammation and have been implicated in promoting apical resorption. This is because neutrophils, which are rich sources of PGE2, are present when the majority of rapid bone loss occurs during the initial stages of apical periodontitis. It has been illustrated clinically that parenteral administration of indomethacin, an inhibitor of cyclooxygenase, can act to suppress resorption of apical hard tissue. The predominant mechanism of bone resorption in a periapical lesion, as in the rest of the body, is the performed by osteoclasts.
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The juvenile teeth of O. compressus are longer than wide, have a thinner base, and lack serrations, similar to O. platypternus teeth. Orthacanthus platypternus from the Craddock Bonebed shark layer in Texas, USA, shows evidence of resorption, and the equivalent of an "enamel pearl." Some of the teeth specimens found at this location show evidence of resorption, which has not been previously observed in other faunas at the same location. Where the superjacent basal tubercle is expected to be resorbed if the teeth were to undergo resorption, the apical button is resorbed instead.
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Osteoclasts are cells of bones that promote bone demineralization or bone resorption. In contrast, Osteoblast promotes calcium absorption by the bone therefore, promoting bone mineralization and formation of new bones. Thus Calcitonin activates osteoblasts, therefore decrease blood calcium levels by decreasing bone breakdown (resorption) by inhibiting osteoclast. Whereas, PTH activates osteoclast and thereby increases blood calcium.
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Bone resorption rates are much higher in post-menopausal older women due to estrogen deficiency related with menopause. Common treatments include drugs that increase bone mineral density. Bisphosphonates, RANKL inhibitors, SERMs—selective oestrogen receptor modulators, hormone replacement therapy and calcitonin are some of the common treatments. Light weight bearing exercise tends to eliminate the negative effects of bone resorption.
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Remodeling begins as early as three to four weeks after fracture and may take 3 to 5 years to complete. The process substitutes the trabecular bone with compact bone. The trabecular bone is first resorbed by osteoclasts, creating a shallow resorption pit known as a "Howship's lacuna". Then osteoblasts deposit compact bone within the resorption pit.
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Internal root resorption may be an indication of pulpal necrosis though it is not possible to diagnose accurately with radiographic presentation of this alone. This is because the pulp tissue apical to the resorptive lesion will still be vital to allow active resorption to take place, it provides the clastic cells with nutrients via a viable blood supply.
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Regardless of the reason, tooth resorption is due to an inflammatory process in response to an insult on one of the above.
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It is not until a few days later that the tail is reabsorbed, due to the higher thyroxin concentrations required for tail resorption.
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Feline odontoclastic resorptive lesions Feline Tooth Resorption (TR) is a syndrome in cats characterized by resorption of the tooth by odontoclasts, cells similar to osteoclasts. TR has also been called "feline odontoclastic resorption lesion" (FORL), neck lesion, cervical neck lesion, cervical line erosion, feline subgingival resorptive lesion, feline caries, or feline cavity. It is one of the most common diseases of domestic cats, affecting up to two-thirds. TRs have been seen more recently in the history of feline medicine due to the advancing ages of cats, but 800-year-old cat skeletons have shown evidence of this disease.
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P. robustus also features resorption of the upper jaw, but resorption in MH1 expands along the front teeth to the canine fossa near the cheek bones, resulting in a mesognathic (somewhat protrusive) face, as opposed to a flat face in P. robustus. Because resorption occurs so close to the cheek bones, this may explain why MH1 does not present flaring cheekbones characteristic of A. africanus. Tooth eruption probably did not affect the remodeling of the lower face as MH1 already had all of its permanent teeth. Nonetheless, smaller cheek tooth size may have permitted a mesognathic face.
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Bones are made of cells called osteoclasts and osteoblasts. Two different kinds of bone resorption are possible: direct resorption, which starts from the lining cells of the alveolar bone, and indirect or retrograde resorption, which takes place when the periodontal ligament has been subjected to an excessive amount and duration of compressive stress.Robling, Alexander G., Alesha B Castillo, and Charles H. Turner, "Biochemical and Molecular Regulation of Bone Remodeling", Annual Review of Biochemical Engineering, (April 3, 2006) pp 1–12 Another important factor associated with tooth movement is bone deposition. Bone deposition occurs in the distracted periodontal ligament.
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The TCIRG1 gene is present in chromosome locus 11q13, which encodes for the a3 subunit of vacuolar H+ ATPase (V-ATPase) that is unique to osteoclasts. The a3 subunit is responsible in anchoring the vacuolar proton pump to the ruffled membrane of osteoclasts. The V-ATPase is important in mediating the transport of hydrogen ions into the resorption lacunae, which is a pit on the bone surface enclosed by the osteoclast for bone resorption. The accumulation of ions in the lacuna facilitates the decomposition of hydroxyapatite crystals by creating an acidic environment, resulting in bone resorption.
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With TJ Chambers he developed the osteoclast lacunar bone resorption assay system.Chambers TJ, Revell PA, Fuller K, Athanasou NA. (1984). Resorption of bone by isolated rabbit osteoclasts. J Cell Science 66: 383 – 399 His work was the first to show that the human osteoclast shares specific surface antigens with macrophages and that the mononuclear human osteoclast precursor circulates in the (CD14+) monocyte fraction.
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J Bone Joint Surgery (A). 78: 1096 – 1112 This led to the discovery of cellular and molecular mechanisms of pathological bone resorption associated with primary and secondary bone tumours, particularly breast cancer metastasis,Athanasou NA, Quinn J. (1992). Human tumour- associated macrophages are capable of bone resorption. Br J Cancer 65: 523 – 526 Quinn JMW, McGee JO'D, Athanasou NA. (1998).
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SLC6A19 is a system B(0) transporter that mediates epithelial resorption of neutral amino acids across the apical membrane in the kidney and intestine.
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Cysts can cause root resorption of adjacent teeth, tooth mobility and can be associated with mandibular fracture. Cyst would usually require surgical management if indicated.
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The maxillary (upper) left (right in photograph) lateral incisor (2nd tooth from the center) is afflicted with internal resorption (termed a pink tooth of Mummery).
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The ANK protein spans the cell membrane and shuttles inorganic pyrophosphate (PPi), a major inhibitor of physiologic and pathologic calcification, bone mineralization and bone resorption.
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Developing the highly invaginated ruffled membrane apposing the resorption compartment allows massive secretory activity. In addition, it permits the vesicular transcytosis of the mineral and degraded collagen from the ruffled border to the free membrane of the cell, and its release into the extracellular compartment. This activity completes the bone resorption, and both the mineral components and collagen fragments are released to the general circulation.
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Experimentally, electrosurgery has been shown to reduce pathologic root resorption and periapical pathology, and a series of pulpal effects including acute and chronic inflammation, swelling and diffuse necrosis. It is reported that this method has high success rate in pulpotomies. However, this method may prove to be more diagnosis and technique sensitive, and it may not be suitable if apical root resorption has occurred.
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Active substances in the milk basic protein fraction promote bone formation and suppress bone resorption. It has been found to decrease the formation of osteoclast pits, which act to break down bone and release minerals for resorption into plasma, MBP helps to reduce this process. It also increases bone mineralization by stimulating proliferation of osteoblasts which are involved in collagen production and bone formation.Kawakami, H. (2005).
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Ribonuclease-enriched lactoferrin has been used to examine how lactoferrin affects bone. Lactoferrin has shown to have positive effects on bone turnover. It has aided in decreasing bone resorption and increasing bone formation. This was indicated by a decrease in the levels of two bone resorption markers (deoxypyridinoline and N-telopeptide) and an increase in the levels two bone formation markers (osteocalcin and alkaline phosphatase).
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Hypercatabolic states, high-dose glucocorticoids, and resorption of large hematomas have all been cited as causes of a disproportionate rise in BUN relative to the creatinine.
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Although not much is known about female reproductive systems in H. heteropsis specifically, other members of the family Histioteuthidae show significant oocyte resorption (oosorption) during maturation.
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The ciliary body has three functions: accommodation, aqueous humor production and resorption, and maintenance of the lens zonules for the purpose of anchoring the lens in place.
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There are, however, exceptions such as cathepsin K, which works extracellularly after secretion by osteoclasts in bone resorption. Cathepsins have a vital role in mammalian cellular turnover.
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Proprioception When roots are retained and used for overdentures, preservation of the periodontal membrane maintains proprioceptive impulses so the patient is aware of occlusal contacts and can control occlusal forces as they did with natural teeth. Loss of proprioception is something which patients can struggle with accepting. Bone Resorption When teeth and roots are extracted, bone resorption ensues. This is greatest in the mandible and can be minimised by retaining roots.
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As soon as the capsule has reached its destination, the magnetic field is destroyed by pressing a button and the drug is released for resorption within milliseconds. The method is used during development or optimization of drug products and contributes significantly to the reduction in development time and costs. Areas of use include the determination of resorption windows, early proof of concept studies, interaction studies, and optimization of pharmaceutical formulations.
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In 1976: Michael and Barsoum researched on patients who had immediate denture placement. They related the amount of bone resorption in relation with different surgical techniques. The above mentioned surgical techniques include extraction without alveoplasty, extraction with labial alveolectomy, and extraction with intraseptal alveoplasty as described by Dean in 1923. The result of their study showed labial alveoloplasty had the most bone resorption occurring at the procedure area.
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The protein encoded by this gene is a lysosomal cysteine protease involved in bone remodeling and resorption. This protein, which is a member of the peptidase C1 protein family, is expressed predominantly in osteoclasts. Cathepsin K is a protease, which is defined by its high specificity for kinins, that is involved in bone resorption. The enzyme's ability to catabolize elastin, collagen, and gelatin allows it to break down bone and cartilage.
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Etidronic acid is a bisphosphonate used to strengthen bone, treat osteoporosis, and treat Paget's disease of bone. Bisphosphonates primarily reduce osteoclastic activity, which prevents bone resorption, and thus moves the bone resorption/formation equilibrium toward the formation side and hence makes bone stronger on the long run. Etidronate, unlike other bisphosphonates, also prevents bone calcification. For this reason, other bisphosphonates, such as alendronate, are preferred when fighting osteoporosis.
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Status Survey and Conservation Action Plan, p.14-p.60, . Embryo resorption may occur if the pika encounters adverse conditions.Macdonald, D.(2001), The New Encyclopedia of Mammals, p.
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Resorption involves degrading chlorophyll to extract the majority of its nutrients.Keskitalo, J., G. Bergguist, P. Gardestrom, and S. Jansson. 2005. A Cellular Timetable of Autumn Senescence. Plant Phys.
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Like other AAS, oxandrolone may worsen hypercalcemia by increasing osteolytic bone resorption. When taken by pregnant women, oxandrolone may have unintended effects such as masculinization on the fetus.
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These experiments showed intact ETC setae appeared to cause fetal resorption in mice, but frozen ETC setae and ETC setal filtrates failed to produce fetal resorptions in mice.
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The first osteons begin to appear within the depths of the growth zone and there are numerous hypertrophied vessels. The medullary canal appears by means of osteoclastic resorption.
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It has reduced osteoclast formation, which signifies a decrease in pro-inflammatory responses and an increase in anti-inflammatory responses which indicates a reduction in bone resorption as well.
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Advice of control and reduction in excessive calcium intake may be recommended by physicians to ensure circulating levels of parathyroid hormones are normal to induce and maintain bone resorption.
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In other countries is prescribed as a bone resorption inhibitor and antihypercalcemic agent. It is not approved for use in the United States, because it has too many adverse effects.
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They may clog up inside the lymphatic vessel around the diaphragm and prevent resorption of peritoneal fluid. In the end, pericardiophrenic lymphadenopathy and ascites may result from this frank invasion.
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It has been observed that some degree of bone resorption occurs at the crest of bone following implant placement. Through extensive investigation, it has been discovered that the extent of bone resorption is related to both the texture of the surfaces of the implant and abutment at and the morphology of the implant- abutment junction (IAJ). A number of investigators have zeroed in on the proposed inflammatory cell infiltrate that forms a zone around the IAJ.Ericsson I, et al.
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Normal bone growth is achieved by a balance between bone formation by osteoblasts and bone resorption (breakdown of bone matrix) by osteoclasts. In osteopetrosis, the number of osteoclasts may be reduced, normal, or increased. Most importantly, osteoclast dysfunction mediates the pathogenesis of this disease. Osteopetrosis is caused by underlying mutations that interfere with the acidification of the osteoclast resorption pit, for example due to a deficiency of the carbonic anhydrase enzyme encoded by the CA2 gene.
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Experiencing some pain following fitting and activation of fixed orthodontic braces is very common and several methods have been suggested to tackle this. The dental displacement obtained with the orthodontic appliance determines in most cases some degree of root resorption. Only in a few cases is this side effect large enough to be considered real clinical damage to the tooth. In rare cases, the teeth may fall out or have to be extracted due to root resorption.
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Transgenic mice lacking MMP-9 develop defects in bone development, intraosseous angiogenesis, and fracture repair. MMP-13 is believed to be involved in bone resorption and in osteoclast differentiation, as knockout mice revealed decreased osteoclast numbers, osteopetrosis, and decreased bone resorption. MMPs expressed by the osteoclast include MMP-9, -10, -12, and -14. apart from MMP-9, little is known about their relevance to the osteoclast, however, high levels of MMP-14 are found at the sealing zone.
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Specifically, the PY motif in the protein is deleted or altered so the E3 ligase (Nedd4) no longer recognizes the channel. This loss of ability to be degraded leads to high amounts of the channel being chronically present in the collecting duct. This results in a hyperaldosteronism-like state, since aldosterone is typically responsible for creating and inserting these channels. The increased sodium resorption leads to increased resorption of water, and hypertension due to an increase in extracellular volume.
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Calcilytics are pharmaceutical drugs that act as antagonists at the calcium- sensing receptor (CaSR). This increases the secretion of parathyroid hormone (PTH), which has a temporary anabolic effect on bone tissue, producing an increase in both bone volume and bone density due to increased bone deposition and resorption. However, long term use of these causes resorption, degrading the bone to raise blood calcium. Consequently, these drugs have been researched for the treatment of osteoporosis, though with only limited success.
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A fixed implant retained denture is completely implant supported therefore further alveolar ridge resorption is avoided, unlike with a tissue supported prosthesis. An improvement in soft tissue health can also be seen.
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Huiskes, R.; Weinans, H.; Vanrietbergen, B., The Relationship between Stress Shielding and Bone- Resorption around Total Hip Stems and the Effects of Flexible Materials. Clin Orthop Relat R 1992, (274), 124-134.
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If it is decided to retain asymptomatic disease-free impacted wisdom teeth, clinical assessment at regular intervals is advisable to prevent undesirable outcomes (pericoronitis, root resorption, cyst formation, tumour formation, inflammation/infection).
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Resorption continues up the dentinal tubules into the tooth crown. The enamel is also resorbed or undermined to the point of tooth fracture. Resorbed cementum and dentin is replaced with bone-like tissue.
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Osteoporosis is a bone-related disease caused by increased rates of bone resorption compared to bone formation. A higher rate of resorption is often caused by increased osteoclastogenesis and results in symptoms of osteopenia such as excessive bone loss and low bone mineral density. Osteoporosis is often triggered in post-menopausal women due to reduced estrogen levels associated with the depletion of hormone-releasing ovarian follicles. Decreasing estrogen levels result in the downregulation of OPG expression and reduced inhibition of RANKL.
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In both didelphys and bicornuate uteri, the non-fusion of the Mullerian ducts results in two distinct uterine cavities. The third and final stage of Mullerian duct development is septal resorption. After the lower Mullerian ducts fuse, a central septum is left behind, and this partition must be eliminated to give rise to a single uterine cavity, cervical canal and vaginal canal. Defects in septal resorption may produce a septate uterus or arcuate uterus, where the septum divides the uterine cavity.
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Metronidazole in combination with alcohol causes severe reactions such as vomiting and flushes in many patients. Tetracycline resorption is reduced by dairy products, antacids and other products containing calcium, magnesium, aluminium as well as iron.
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In this stage, the teeth are termed to be ankylosed. This migration and repopulation process, termed replacement resorption, will continue and thus the teeth root will become fused with the bone tissue adjacent to it.
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Since the kidney's resorption capacity takes longer to re- establish, there is a minor lag in function that follows recovery of flow. A good reference range for plasma creatinine is between 0.07 - 0.12 mmol/L.
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For example, chin implants that are immobilised create pressure on the anterior mandible which can cause an increase in bone resorption. Facial implants that are placed in a supraperiosteal plane centrally and subperiosteal plane laterally minimise bone resorption. The supraperiosteal plane placement of the implant minimises the degree of contact to the bone as the implant is immobilised and the subperiosteal plane has lateral pockets that fixate the implant. Chin implants can also be fixated and equally remove pressure from bone through the use of screw fixation.
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Bone is a common site of metastasis in cancers such as breast, prostate and lung cancer. In osteolytic bone metastases, tumour cells migrate to the bone and release cytokines such as parathyroid hormone-related protein (PTHrP), IL-8 and PGE2. These cytokines act on osteoblasts to increase RANKL and decrease OPG expression resulting in excess bone resorption. During resorption osteoclasts release nutrients such as growth factors and calcium from the mineralised bone matrix which cultivates a supportive environment for the proliferation and survival of tumour cells.
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Not all sequelae of trauma are immediate and many of them can occur months or years after the initial incident thus required prolonged follow-up. Common complications are pulpal necrosis, pulpal obliteration, root resorption and damage to the successors teeth in primary teeth dental trauma. The most common complication was pulp necrosis (34.2%). 50% of the tooth that have trauma related to avulsion experienced ankylotic root resorption after a median TIC (time elapsed between the traumatic event and the diagnosis of complications) of 1.18 years.
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Coumestrol has been shown to decrease bone resorption and promote the mineralization of bone in vitro and in vivo; daily injections of coumestrol were shown to reduce bone loss in rats who had undergone an ovariectomy.
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May 2006. A history of acquired racquet nails (brachyonychia) may be indicative of bone resorption. Parathyroid adenomas are very rarely detectable on clinical examination. Surgical removal of a parathyroid tumor eliminates the symptoms in most patients.
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However, FORLs can develop in the absence of inflammation. The natural inhibition to root resorption provided by the lining of the root may be altered by increased amounts of Vitamin D, in cats supplied by their diet.
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The interaction potential is low. Resorption of other pharmaceutical drugs can be reduced because oral macrogol accelerates intestinal passage, but this is seldom clinically relevant. For antiepileptic drugs, such a mechanism has been described in rare cases.
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The substance can inhibit the resorption of other drugs, as well as fat soluble vitamins (A, D, E, K) and folate, from the gut. Resulting lower blood levels can be clinically problematic with immunosuppressant and antiepileptic drugs.
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The clinical importance of the glycemic index is controversial,U Satyanarayana: Biochemistry. Elsevier Health Sciences, 2014, , p. 508. as foods with high fat contents slow the resorption of carbohydrates and lower the glycemic index, e.g. ice cream.
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An average of 19 orange oocytes are laid in these areas. Both parents guard the nest as the eggs develop. Eggs hatch within 8 to 9 days. Yolk resorption takes about 9 to 10 days after hatching.
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According to the degree of diminishment of the volume and contour caused by the fat- resorption, the patient might require additional sessions of fat-transfer therapy to achieve the desired size, shape, and contour of the buttocks.
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As teeth flex under pressure, the arrangement of teeth touching each other, known as occlusion, causes tension on one side of the tooth and compression on the other side of the tooth. This is believed to cause V-shaped depressions on the side under tension and C-shaped depressions on the side under compression. When tooth destruction occurs at the roots of teeth, the process is referred to as internal resorption, when caused by cells within the pulp, or external resorption, when caused by cells in the periodontal ligament.
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Tooth Decay Any remaining tooth structure within the oral cavity is subject to developing caries and is often the result of lack of topical fluoride application, poor diet and poor oral hygiene. Caries can be found at the root face or root surface where gingival recession has occurred. It is important to encourage patients to use a fluoride containing toothpaste over the denture abutments to minimise tooth surface loss and risk further infection. Bone Resorption Another tissue change that can result from wearing an overdenture is resorption of the alveolar bone.
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Embryo loss (also known as embryo death or embryo resorption) is the death of an embryo at any stage of its development which in humans, is between the second and eighth week of gestation. Failed development of an embryo often results in the disintegration and assimilation of its tissue in the uterus. Loss during the early stages of prenatal development of the fetus results in the similar process of fetal resorption. Embryo loss often happens without an awareness of pregnancy, and an estimated 40 to 60% of all embryos do not survive.
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In the space (or microgravity) environment the effects of unloading varies significantly among individuals, with sex differences compounding the variability. Differences in mission duration, and the small sample size of astronauts participating in the same mission also adds to the variability to the musculoskeletal disorders that are seen in space. In addition to muscle loss, microgravity leads to increased bone resorption, decreased bone mineral density, and increased fracture risks. Bone resorption leads to increased urinary levels of calcium, which can subsequently lead to an increased risk of nephrolithiasis.
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Strontium ranelate is an antiosteoporotic agent which both increases bone formation and reduces bone resorption, resulting in a rebalance of bone turnover in favor of bone formation. This is similar to the effects of choline-stabilized orthosilicic acid. Strontium ranelate stimulates the calcium-sensing receptors and leads to the differentiation of pre-osteoblast to osteoblast which increases the bone formation. Strontium ranelate also stimulates osteoblasts to secrete osteoprotegerin in inhibiting osteoclasts formed from pre-osteoclasts in relation to the RANKL system, which leads to the decrease of bone resorption.
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Internal resorption of the left maxillary lateral incisor (right in photograph), giving rise to the appearance termed "Pink tooth of Mummery" Internal resorption may sometimes follow dental trauma (although in other cases it appears unrelated). This is where the dentin is resorbed and replaced instead by hyperplastic, vascular pulp tissue. As this process starts to approach the external surface of the tooth, a pink hue of this replacement pulp tissue may become visible through the remaining overlying tooth substance. This appearance is sometimes termed "pink tooth of Mummery".
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This permits characterization of osteoclasts by their staining for high expression of tartrate resistant acid phosphatase (TRAP) and cathepsin K. Osteoclast rough endoplasmic reticulum is sparse, and the Golgi complex is extensive. At a site of active bone resorption, the osteoclast forms a specialized cell membrane, the "ruffled border", that opposes the surface of the bone tissue. This extensively folded or ruffled border facilitates bone removal by dramatically increasing the cell surface for secretion and uptake of the resorption compartment contents and is a morphologic characteristic of an osteoclast that is actively resorbing bone.
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Bifrontal cranioplasties are associated with significantly higher infection rates and higher rates for reoperation. Other risk factors for infection include previous infections, contact between sinuses and operation site, devascularized scalp (loss of blood supply in the scalp), previous operations, and type of injury. Bone resorption is another complication of cranioplasty with a complication rate of 0.7-17.4%. Bone resorption occurs when the autologous graft does not have blood supply due to devitalisation, or when scar tissues or soft tissues remain on the edge of the cranial defect during cranioplasty.
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Replacement activity in Postosuchus was different from that of crocodiles, since the replacement tooth didn't fit directly in the pulp cavity of the old tooth, but grew until resorption of the old tooth was complete.Chatterjee (1985), p. 413.
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This reduced delivery of solute to the collecting tubule and medullary collecting duct allows increased water resorption and higher concentration of urine, which leads to reversal of nephrogenic diabetes insipidus by a means that is independent of vasopressin.
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Sculpture gradually disappearing and becoming smooth towards body whorl excepting irregular growth lines, but remaining faintly at base. Sutural ramp moderately rugose. Umbilicus circular, narrow and deep. Nacreous part of parietal wall widely extended beyond umbilicus by secondary resorption.
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In external resorption, after root canal therapy is performed, the flap is raised over the tooth and the defect removed from the root surface with a round bur. Retrograde application of MTA to the root surface is then completed.
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This increases bone resorption. In chronic kidney failure the problem is more specifically failure to convert vitamin D to its active form in the kidney. The bone disease in secondary hyperparathyroidism caused by kidney failure is termed renal osteodystrophy.
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The primary extracellular matrix components and cell-surface receptors which aid in metastasis are: ;Integrin signalling: Integrin αvβ3 (a cell-surface adhesion molecule) is important for tumor attachment, cell-to-cell communication between the breast tumor cells and the environment in bone, osteoclast bone resorption and angiogenesis. Integrin-mediated adhesion between cancer cells and osteoclasts in bone metastases induces phosphorylation of extracellular signal-regulated kinases (ERK1/2) in osteoclasts, which in turn induces osteoclast differentiation and survival.MetaBre ;Cancer cell-blood platelet interaction: Metastatic breast- cancer cells excrete lysophosphatidic acid (LPA) which binds to receptors on tumor cells, inducing cell proliferation and release of cytokines(IL-6 and IL-8, potent bone resorptive agents) and stimulating bone resorption. After the breast-cancer cells have left the primary tumor, they interact with the bone microenvironment and secrete osteolytic factors capable of osteoclast formation and bone resorption.
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This mineral eventually presents resorption shape. The reaction rim constituted by amphibole and/or biotite is commonly observed. The amphibole is of high alkali, such as alkaline hornblende and riebeckite. The alkaline clinopyroxene and amphibole are characteristics of typical alkaline rocks.
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Alcohol can increase the absorption rate. Monoamine oxidase (MAO) breaks down biogenic amines and prevents excessive resorption. MAO inhibitors (MAOIs) are also used as medications for the treatment of depression to prevent MAO from breaking down amines important for positive mood.
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ATPase, H+ transporting, lysosomal 38kDa, V0 subunit d2 is a protein in humans that is encoded by the ATP6V0D2 gene. It is part of proton pumps in the plasma membranes of osteoclasts and aids with extracellular acidification in bone resorption.
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Biological significance of Milk Basic Protein (MBP) for bone health. FSTR, 11, 1. Daily supplementation with 40 mg of MBP over 6 months has been shown to result in increased bone mineral density and lower urinary markers of bone resorption.
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However, in the large and long bones of many dinosaurian taxa, resorption of internal and external bone proceeds even as new cortical bone continues to be deposited, so that growth lines deposited early in development may need to be inferred.
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Moreover, multiple biopsies using double tetracycline labelling are necessary for the same patient to assess treatment response or disease progression. Another drawback is that the iliac crest may not provide a true measurement of changes in bone metabolism at the lumbar spine or hip as considerable differences in regional bone metabolism estimates are observed at different skeletal sites. Revell et al. describes the measurement of various parameters such as trabecular bone volume, osteoid volume, osteoid surface, active osteoblastic surface, resorption surface, osteoclastic resorption surface, mineralization front, osteoid index, appositional rate, and osteoclastic index via histomorphometric analysis of bone samples.
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Osteoclasts in close proximity to the root surface will resorb the root surface cementum and underlying root dentin. This can vary in severity from evidence of microscopic pits in the root surface to complete devastation of the root surface. When there is insult leading to inflammation (trauma, bacteria, tooth whitening, orthodontic movement, periodontal treatment) in the root canal/s or beside the external surface of the root, cytokines are produced, the RANKL system is activated and osteoclasts are activated and resorb the root surface. If the insult is transient, resorption will stop and healing will occur, this is known as transient inflammatory resorption.
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Tooth ankylosis is the pathological fusion between alveolar bone and the cementum of teeth, which is a rare phenomenon in the deciduous dentition and even more uncommon in permanent teeth. Ankylosis occurs when partial root resorption is followed by repair with either cementum or dentine that unites the tooth root with the alveolar bone, usually after trauma. However, root resorption does not necessarily lead to tooth ankylosis and the causes of tooth ankylosis remain uncertain to a large extent. However, it is evident that the incident rate of ankylosis in deciduous teeth is much higher than that of permanent teeth.
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It is believed to be unrelated to squamous cell carcinoma of the breast which probably arises from different cell types. The keratin plugs (debris) produced by SMOLD have been proposed as the cause for recurrent subareolar abscesses by causing secretory stasis. The epidermalized lining has also different permeability than the normal lining, hindering resorption of glandular secretions. The resorption is necessary to dispose of stalled secretions inside the duct - and at least equally important it affects osmotic balance which in turn is an important mechanism in the control of lactogenesis (this is relevant both in puerperal and nonpuerperal mastitis).
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In this way, a closed subosteoclastic compartment is created between the ruffled border and the bone that is undergoing resorption. The osteoclasts secrete hydrogen ions, collagenase, cathepsin K and hydrolytic enzymes into this compartment. Resorption of bone matrix by the osteoclasts involves two steps: (1) dissolution of inorganic components (minerals), and (2) digestion of organic component of the bone matrix. The osteoclasts pump hydrogen ions into subosteoclastic compartment and thus create an acidic microenvironment, which increases solubility of bone mineral, resulting in the release and re-entry of bone minerals into the cytoplasm of osteoclasts to be delivered to nearby capillaries.
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Loss of teeth alters the form of the alveolar bone in 91% of cases. In addition to this resorption of bone in the vertical and anterioposterior dimensions, the alveolus also resorbs faciolingually, thus diminishing the width of the ridge. What initially began as a sort of tall, broad, bell curve-shaped ridge (in the faciolingual dimension) eventually becomes a short, narrow, stumpy sort of what doesn't even appear to be a ridge. Resorption is exacerbated by pressure on the bone; thus, long-term complete denture wearers will experience more drastic reductions to their ridges that non-denture wearers.
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Those individuals who do wear dentures can decrease the amount of bone loss by retaining some tooth roots in the form of overdenture abutments or have implants placed. Note that the depiction above shows a very excessive change and that this many take many years of denture wear to achieve. Ridge resorption may also alter the form of the ridges to less predictable shapes, such as bulbous ridges with undercuts or even sharp, thin, knife-edged ridges, depending of which of many possible factors influenced the resorption. Bone loss with missing teeth, partials and complete dentures is progressive.
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Microdamage in bone occurs as the result of repetitive events of cycling loading, and appears to be associated with osteocyte death by apoptosis, which appear to secrete a signal to target osteoclasts to perform remodeling at a damaged site. Under normal conditions, osteocytes express high amounts of TGF-β and thus repress bone resorption, but when bone grows old, the expression levels of TGF-β decrease, and the expression of osteoclast-stimulatory factors, such as RANKL and M-CSF increases, bone resorption is then enhanced, leading to net bone loss. Mechanical stimulation of osteocytes results in opening of hemichannels to release PGE2 and ATP, among other biochemical signaling molecules, which play a crucial role in maintaining the balance between bone formation and resorption. Osteocyte cell death can occur in association with pathologic conditions such as osteoporosis and osteoarthritis, which leads to increased skeletal fragility, linked to the loss of ability to sense microdamage and/or signal repair.
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Pindolol is rapidly and well absorbed from the GI tract. It undergoes some first-pass-metabolization leading to an oral bioavailability of 50-95%. Patients with uremia may have a reduced bioavailability. Food does not alter the bioavailability, but may increase the resorption.
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A two jaw surgery can also be performed where Bilateral Sagittal Split Osteotomy can be done to correct any Antero-Posterior changes of the mandible. However, with two jaw surgery a relapse leading to bite opening may happen due to condylar remodeling and resorption.
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The loss of a shell in the adult form of some gastropods is achieved by the discarding of the larval shell; in other gastropods and in cephalopods, the shell is lost or demineralized by the resorption of its carbonate component by the mantle tissue.
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The protons are then used for bone resorption. In renal cells, V-ATPases are used to pump protons into the urine. This facilitates bicarbonate reabsorption into the blood. The ATP6V0A2 gene encodes the a2 isoform of the a-subunit (present in the V0 domain).
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Alterations in the gingiva such as fistulas or abscesses and radiographic signs such as periapical lesions and external root resorption are used in some studies to diagnose pulp necrosis however other studies state that these factors alone are not enough to diagnose a necrotic pulp.
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Root resorption following traumatic dental injuries, whether located along the root surface or within the root canal appears to be a sequel to wound healing events, where a significant amount of the PDL or pulp has been lost due to the effect of acute trauma.
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Flexible hydrogel-HA composite, which has a mineral-to-organic matrix ratio approximating that of human bone Artificial bone refers to bone-like material created in a laboratory that can be used in bone grafts, to replace human bone that was lost due to severe fractures, disease, etc. Bone fracture, which is a complete or partial break in the bone, is a very common condition that has more than three million US cases per year. Human bones have the ability to regenerate themselves by cycle of bone resorption and bone formation. The cell responsible for bone resorption is osteoclast, while the cell responsible for bone formation is osteoblast.
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External cervical resorption is a localised resorptive lesion in the cervical area of the tooth, below the epithelial attachment. This rarely involves the pulp. Prolonged insult leads to vertical and horizontal growth of the lesion. It is commonly caused by trauma, periodontal treatment, or tooth whitening.
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Osteocytes appear to be enriched in proteins that are resistant to hypoxia, which appears to be due to their embedded location and restricted oxygen supply. Oxygen tension may regulate the differentiation of osteoblasts into osteocytes, and osteocyte hypoxia may play a role in disuse-mediated bone resorption.
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The medical complications possible to a liposclupture buttocks augmentation include the bodily resorption of some of the injected adipose fat, asymmetric contour of the corrected body area, an irregular contour to the body, seroma, abscess (pus enclosed by inflamed tissue), cellulitis (subcutaneous connective-tissue inflammation), and paresthesia.
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After complete resorption only connective tissue will remain. Occasionally, absorbable sutures can cause inflammation and be rejected by the body rather than absorbed. Twelve nonabsorbable sutures in a person's lower back. Non- absorbable sutures are made of special silk or the synthetics polypropylene, polyester or nylon.
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Generalized bone loss occurs most frequently as horizontal bone loss. Horizontal bone loss manifests as a somewhat even degree of bone resorption so that the height of the bone in relation to the teeth has been uniformly decreased, as indicated in the radiograph to the right.
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Poland was adopted by her parents, Hartson and Tracy Poland, as a baby. She was introduced to her birth mother at age 13. At age 14, Poland was diagnosed with condylar resorption, a rare disease causing her jaw to essentially break apart. Her condition impaired her ability to sing.
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The muscle attachments to the area of alveolar ridge can be left undisturbed. Postoperative bone resorption and remodeling can be reduced as the periosteal attachment to the underlying bone is maintained. The height of the ridge can be preserved while reducing the labial prominence of the alveolar ridge.
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Pharmacokinetics and bone resorption evaluation of a novel Cathepsin K inhibitor (VEL‐0230) in healthy adult horses. Journal of veterinary pharmacology and therapeutics. Medivir has a cathepsin K inhibitor, MIV-711 (L-006235), in Phase IIa clinical trial, as a disease modifying osteoarthritis drug, as of October 2017.
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Ankylosis of deciduous teeth may rarely occur. The most commonly affected tooth is the mandibular (lower) second deciduous molar. Partial root resorption first occurs and then the tooth fuses to the bone. This prevents normal exfoliation of the deciduous tooth and typically causes impaction of the permanent successor tooth.
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Neurochondrin proteins induce hydroxyapatite resorptive activity in bone marrow cells resistant to bafilomycin A1, an inhibitor of macrophage- and osteoclast-mediated resorption. Expression of the gene is localised to chondrocyte, osteoblast, and osteocyte in the bone and to the hippocampus and Purkinje cell layer of cerebellum in the brain.
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Andreolepsis was capable of shedding its teeth by basal resorption, which is considered a rather primitive mode of tooth replacement.This makes it informative about the evolution of teeth. Fossil remains are mostly limited to scales, platelets and fragmented bones. At first only the species A. hedei was described.
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Processes such as bone remodeling (loss and gain of bone tissue) in the jaws and inflammation of soft tissue in response to the oral microbiota are clinically important for edentulous people. For example, bone resorption in the jaw is frequently how the teeth were able to detach in the first place; the jaw in an edentulous area undergoes further resorption even after the teeth are gone; and insertion of dental implants can elicit new bone formation, leading to osseointegration. Meanwhile, bacteria and yeasts of the oral cavity and the immune system of their host create an immensely complicated and constantly changing interplay that presents clinically as gingivitis, caries, stomatitis, and other periodontal pathology.
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There are many other factors to consider. In healthy bone tissue there is a homeostasis between bone resorption and ossification. Diseased or damaged bone is resorbed through the osteoclasts mediated process while osteoblasts form new bone to replace it, thus maintaining healthy bone density. This process is commonly called remodelling.
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Osteoprotegerin (OPG) is also secreted by osteoclasts and stromal cells; this inhibits RANKL and therefore osteoclast activity. The pathophysiology of stimulation of osteoclasts in the process of inflammatory resorption is unknown. One thought is that the presence of bacteria plays a role. Bacterial presence leads to pulpal or peri-periapical inflammation.
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In bone, osteoclasts are found in pits in the bone surface which are called resorption bays, or Howship's lacunae. Osteoclasts are characterized by a cytoplasm with a homogeneous, "foamy" appearance. This appearance is due to a high concentration of vesicles and vacuoles. These vacuoles include lysosomes filled with acid phosphatase.
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Periradicular surgeries involve the root surface. These include apicoectomy (removal of a root end), root resection (removal of an entire root), repair of an injured root due to perforation or resorption, removal of broken fragments of the tooth or a filling material, and exploratory surgery to look for root fractures.
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As with any surgery there is a risk of infection, postoperative bleeding, formation of a blood clot, and severe swelling. Asymmetry is a risk with all forms of cheek augmentation. This can occur due to uneven resorption, implant displacement, or shifting. This shift can happen due to swelling, trauma or scarring.
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Under conditions of sub-optimal dietary Ca2+, normal serum calcium levels in TRPV6 KO mice are maintained at the expense of bone. TRPV6 plays an important role in osteoclasts but not in osteoblasts. In mice, TRPV6 depletion results in increased osteoclasts differentiation whereas TRPV5 is essential for proper osteoclastic bone resorption.
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Kv1.3 is also considered a therapeutic target for the treatment of obesity, for enhancing peripheral insulin sensitivity in patients with type-2 diabetes mellitus, and for preventing bone resorption in periodontal disease. A genetic variation in the Kv1.3 promoter region is associated with low insulin sensitivity and impaired glucose tolerance.
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Adenosine receptors play a key role in the homeostasis of bone. The A1 receptor has been shown to stimulate osteoclast differentiation and function.Kara FM, Doty SB, Boskey A, Goldring S.. (2010). Adenosine A1 Receptors (A1R) Regulate Bone Resorption II Adenosine A1R Blockade or Deletion Increases Bone Density and Prevents Ovariectomy-Induced Bone Loss.
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Cysts can be common lesions found in the jaw. They are defined as cavities filled with fluid or semi-fluid content, created from the resorption of bone. They can wholly or partly be lined by epithelium and connective tissue. They are not to be confused with abscesses, which are cavities filled with pus.
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Multiple visits with application of formocresol in pulpotomy is used to fix the radicular pulp completely to reduce pulp infection. The radicular pulp was theoretically sterilized and devitalized, thereby reducing infection and internal resorption. Another form of nonchemical devitalization emerged: electrosurgical pulpotomy. Electrocautery releases heat that denatures pulp and reduces bacterial contamination.
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Females can have 1 to 3 litters a year with each litter consisting of 4 to 6 young. The occurrence of embryo resorption has been seen in S. aquaticus; this loss of in-utero litters is attributed to some type of habitat disturbance such as flooding, which may cause overcrowding to occur.
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OPG plays an important role in bone metabolism as a decoy receptor for RANKL in the RANK/RANKL/OPG axis, inhibiting osteoclastogenesis and bone resorption. OPG has also been shown to bind and inhibit TNF-related apoptosis-inducing ligand (TRAIL) which is responsible for inducing apoptosis in tumour, infected and mutated cells.
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Although a number of surrogate biomarkers exist for measuring the metabolic products of bone resorption, the serum CTX marker was chosen because it is both highly correlated to bone turnover rate and already available for detection in a laboratory test carried out by a major lab testing corporation. The CTX test measures for the presence and concentration of a crosslink peptide sequence of type I collagen, found, among other tissues, in bone. This specific peptide sequence relates to bone turnover because it is the portion that is cleaved by osteoclasts during bone resorption, and its serum levels are therefore proportional to osteoclastic activity at the time the blood sample is drawn. Serum levels in healthy patients not taking bisphosphonates tends to hover above 300 pg/mL.
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J Pathol 225:151-156 In addition, his work has studied synovial and inflammatory macrophages and their role in osteoarthritis, rheumatoid arthritis, infection and Paget disease.Fujikawa Y, Sabokbar A, Neale S, Athanasou NA. (1996) Human osteoclast formation and bone resorption by monocytes and synovial macrophages in rheumatoid arthritis. Ann Rheum Dis 55: 1 – 7 Itonaga I, Fujikawa Y, Sabokbar A, Athanasou NA. (2000). The effect of osteoprotegerin and osteoprotegerin ligand on human arthroplasty macrophage-osteoclast differentiation. Ann Rheum Dis 59: 26 - 31. Knowles H, Moskovsky L, Thompson MS, Grunhen J, Chen X, Kashima T, Athanasou NA (2012) Chondroclasts are mature osteoclasts which are capable of cartilage matrix resorption Virchows Archiv 46:205-210 Sun SG, Lau YS, Itonaga I, Sabokbar A, Athanasou NA. (2006).
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Bone lesions are caused by an imbalance of regulatory factors, characterized by an increased depletion and resorption of old bone tissue and a decrease in bone rebuilding, known as bone remodeling. This imbalance is due to a flooding of regulatory factors released by specific tumors, thus overwhelming the tissue repair system and resulting in these lesions. The over-activity of osteoclasts can also cause hypercalcemia, which can cause damage to the kidneys and requires additional medication and monitoring. In multiple myeloma, an increased number of myeloma cells block osteoblasts from creating new bone, while these cancerous cells also release factors that cause an upregulation on osteoclasts, causing an increasing in bone tissue resorption and an overall breakdown of bone integrity.
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Organization of primary osteons varies depending on the element and even locally within the same section. The medullary cavity in all the elements are lined by endosteally lamellated bone the extent of which varies depending on the position and type of element. Secondary reconstruction is prevalent in the inner cortex resulting in enlarged resorption cavities .
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Fourth edition. Wiley & Sons, Hoboken, NJ. Once nitrogen and other nutrients have been extracted from chlorophyll, the nutrients will travel to other tissues of the plant. Resorption is what causes leaves in the fall to change colors. Carotenoids in the leaves are slower to degrade than chlorophyll, so autumn leaves appear yellow and orange.
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CASS4 has been reported to play a modifying role in cystic fibrosis severity, progression and comorbid conditions. The CAS family member NEDD9 has also been shown to interact directly with AURKA (encoding Aurora-A kinase) to regulate cell cycle and ciliary resorption; it is possible that CASS4 may similarly interact with aurora-A kinase.
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Acquired racquet nail is associated with acroosteolysis and psoriatic arthropathy. Acquired racquet nail may also be diagnostic of bone resorption in hyperparathyroidism. Racquet nail often presents with other nail conditions such as onycholysis, koilonychia, pachyonychia, Muehrcke's lines, leuconychia, and half-and-half nails. Cosmetic surgery can be used to improve the appearance of the nails.
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Bone Remodeling is characterized by deposition and resorption of bone at different sites of a bone in the body. This usually leads to change in size or shape of the body. Bone Modeling is known as formation of new bone from either cartilage or by direct deposition. Growth Sites is a term proposed by Baume.
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Skeletal lesions can be specifically bilateral, symmetric and multifocal, exhibiting different types of bone resorption. Pathologic fractures of the femoral neck and spine can potentially initiate serious complications. Because pediatric primary hyperparathyroidism is frequently associated with pathologic fractures it can be misdiagnosed as osteogenesis imperfecta. Pediatric patients with primary hyperparathyroidism are best remedied by parathyroidectomy.
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Teriparatide is a portion of human parathyroid hormone (PTH), amino acid sequence 1 through 34, of the complete molecule (containing 84 amino acids). Endogenous PTH is the primary regulator of calcium and phosphate metabolism in bone and kidney. PTH increases serum calcium, partially accomplishing this by increasing bone resorption. Thus, chronically elevated PTH will deplete bone stores.
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Necrotic bone does not undergo resorption; therefore, it appears relatively more opaque. Attempts at repair of ischaemic-damaged bone will usual occur in 2 phases. First, when dead bone abuts live marrow, capillaries and undifferentiated mesenchymal cells grow into the dead marrow spaces, while macrophages degrade dead cellular and fat debris. Second, mesenchymal cells differentiate into osteoblasts or fibroblasts.
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Osteoclasts are the most prominent examples of MGCs and are responsible for the resorption of bones in the body. Like other MGCs they are formed from the fusion of Monocyte/Macrophage precursors. However, unlike other MGCs, the fusion pathway they originate from is well elucidated. They also do not ingest foreign materials and instead absorb bone matrix and minerals.
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Askmyr MK et al.: Towards a better understanding and new therapeutics of osteopetrosis. Br J Haematol 140:597, 208 Carbonic anhydrase is required by osteoclasts for proton production. Without this enzyme hydrogen ion pumping is inhibited and bone resorption by osteoclasts is defective, as an acidic environment is needed to dissociate calcium hydroxyapatite from the bone matrix.
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PTHrP is critical in intraosseous phase of tooth eruption where it acts as a signalling molecule to stimulate local bone resorption. Without PTHrP, the bony crypt surrounding the tooth follicle will not resorb, and therefore the tooth will not erupt. In the context of tooth eruption, PTHrP is secreted by the cells of the reduced enamel epithelium.
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Osteopetrosis is generic name that represents a group of heritable conditions in which there is a defect in osteoclastic bone resorption. Both dominant and recessive osteopetrosis occur in humans. Autosomal dominant osteopetrosis shows mild symptoms in adults experiencing frequent bone fractures due to brittle bones. A more severe form of osteopetrosis is termed autosomal recessive infantile malignant osteopetrosis.
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It is not clear whether this narrowing is the pathogenesis of the disease or a secondary phenomenon. It has been proposed that a positive biofeedback loop may exist, where raised ICP (intracranial pressure) causes venous narrowing in the transverse sinuses, resulting in venous hypertension (raised venous pressure), decreased CSF resorption via arachnoid granulation and further rise in ICP.
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Alveolar bone loss is closely associated with periodontal disease. Periodontal disease is the inflammation of the gums. Studies in osteoimmunology have proposed 2 models for alveolar bone loss. One model states that inflammation is triggered by a periodontal pathogen which activates the acquired immune system to inhibit bone coupling by limiting new bone formation after resorption.
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Zinc oxide-eugenol (ZOE) was the first agent to used for preservation. In recent years, glutaraldehyde has been proposed as an alternative to formocresol based on: its superior fixative properties, and low toxicity. A nonaldehyde chemical, ferric sulfate, has received some attention recently as a pulpotomy agent. It minimizes the chances for inflammation and internal resorption.
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Clinical Calcium, 16(10), 1632. Direct effects have been identified between MBP and strengthening of bones, through its influences on bone remodelling (formation and resorption) and enhancement bone mineral density. These actions may be beneficial for pre-menopausal and menopausal women in particular, as increased bone mineral density decreases the risk of fractures associated with osteoporosis.
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For example, when creating scaffolds to support the growth of bone, researchers may mimic osteoclast resorption pits. Researchers have successfully used DNA origami-based nanobots capable of carrying out logic functions to achieve targeted drug delivery in cockroaches. It is said that the computational power of these nanobots can be scaled up to that of a Commodore 64.
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Generally, the first bones to show symptoms via X-ray are the fingers. Furthermore, brown tumors, especially when manifested on facial bones, can be misdiagnosed as cancerous. Radiographs distinctly show bone resorption and X-rays of the skull may depict an image often described as "ground glass" or "salt and pepper". Dental X-rays may also be abnormal.
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Remodeling responds also to functional demands of the mechanical loading. In the first year of life, almost 100% of the skeleton is replaced. In adults, remodeling proceeds at about 10% per year.Wheeless Textbook An imbalance in the regulation of bone remodeling's two sub-processes, bone resorption and bone formation, results in many metabolic bone diseases, such as osteoporosis.
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Firmicutes make up the largest portion of the mouse and human gut microbiome. The division Firmicutes as part of the gut flora has been shown to be involved in energy resorption, and potentially related to the development of diabetes and obesity.Komaroff AL. The Microbiome and Risk for Obesity and Diabetes. JAMA. Published online December 22, 2016. doi:10.1001/jama.
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Ameloblastomas can be found both in the maxilla and mandible. Although, 80% are situated in the mandible with the posterior ramus area being the most frequent site. The neoplasms are often associated with the presence of unerupted teeth, displacement of adjacent teeth and resorption of roots. Symptoms include a slow-growing, painless swelling leading to facial deformity.
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Bone is constantly being created and replaced in a process known as remodeling. This ongoing turnover of bone is a process of resorption followed by replacement of bone with little change in shape. This is accomplished through osteoblasts and osteoclasts. Cells are stimulated by a variety of signals, and together referred to as a remodeling unit.
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65: p. 899-910. : O2 → (NADPH-oxidase) O2− ∙ → (superoxide dismutase) H2O2 → (catalase) H2O + O2 : TRAP-Fe3+ (purple) + O2− ∙→ TRAP-Fe2+ (pink) + O2 : H2O2 \+ TRAP-Fe2+ (pink) → HO∙ \+ HO− \+ TRAP-Fe3+ producing hydroxyl radicals, hydrogen peroxide, and singlet oxygen. In osteoclasts, ROS are generated at the ruffled border and seem to be required for resorption and degradation to occur.
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The recovery phase occurs next, with resorption of the leaked fluid into the bloodstream. This usually lasts two to three days. The improvement is often striking, and can be accompanied with severe itching and a slow heart rate. Another rash may occur with either a maculopapular or a vasculitic appearance, which is followed by peeling of the skin.
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Distal clavicular osteolysis (DCO) is often associated with problems weightlifters have with their acromioclavicular joints due to high stresses put on the clavicle as it meets with the acromion. This condition is often referred to as "weight lifter's shoulder". Medical ultrasonography readily depicts resorption of the distal clavicle as irregular cortical erosions, whereas the acromion remains intact.Arend CF. Ultrasound of the Shoulder.
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The missense mutation I282N leads to a macrophage-mediated autoinflammatory disease called Lupo Pstpip2 (Pstpip2Lupo/Lupo ). It is characterized by skin necrosis, inflammation of paws, ears and inflammatory bone resorption. Another mutation in Pstpip2, L98P, was described in chronic multifocal osteomyelitis (cmo) mice. This disease is also autoinflammatory, and causes inflammatory infiltrate of polymorphonuclear leukocytes, macrophages, lymphocytes, plasma cells and osteoclasts.
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Engelman MJ, Sorensen JA, Moy P. Optimum placement of osseointegrated implants. J Prosthet Dent. 1988;59:467–73. First evidence of integration occurs after a few weeks, while more robust connection is progressively effected over the next months or years. Implants that possess a screw-root form design result in bone resorption followed by interfacial bone remodeling and growth around the implant.
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Aldosterone receptors are present on the epithelial cells of the distal nephron in the kidney. Aldosterone activates sodium channels that result in sodium resorption from the urine. Increased sodium and water retention results in systemic arterial hypertension. This increase in active sodium reabsorption generates an electrochemical gradient that leads to passive transfer of potassium from the tubular cells into the urine.
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The bone edema in arthritis mutilans can be treated with TNF inhibitors in the short term: a 2007 study found that the bone edema associated with psoriatic arthritis (of which arthritis mutilans is a subtype) responded to TNF inhibitors with "dramatic" improvement, but the study was not determinative of whether TNF inhibitors would prevent new bone formation, bone fusion, or osteolysis (bone resorption).
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Based on examination of more than 700 examples, the BHH diamonds range in color from colorless to yellow and brown, and most are transparent and colorless. The majority are sharp-edged octahedra, but ~45% were dodecahedral due to resorption of octahedra. Inclusions of garnet, olivine, clinopyroxene and rutile were found in a few specimens.Banas, A., Stachel, T., Muelenbachs, K. and McCandless, T. 2007.
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Because of this, osteoclasts were thought to be derived from cells in connective tissue. Studies that observed that bone resorption could be restored by bone marrow and spleen transplants helped prove osteoclasts hematopoietic origin. Other multinucleated giant cell formations can arise from numerous types of bacteria, diseases, and cell formations. Giant cells are known to develop when infections are also present.
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Micrograph of a brown tumor (left of image). H&E; stain. Brown tumours consist of fibrous tissue, woven bone and supporting vasculature, but no matrix. The osteoclasts consume the trabecular bone that osteoblasts lay down and this front of reparative bone deposition followed by additional resorption can expand beyond the usual shape of the bone, involving the periosteum thus causing bone pain.
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Tooth ankylosis can be recognised clinically by the loss of physiological mobility, and a high P note. It may also be detected radiographically, loss of periodontal ligament space and evidence of replacement resorption. Ankylosis usually initially occurs on the labial and lingual root surfaces making radiographic detection in the early stages difficult. Early diagnosis allows the practitioner to plan for future complications.
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Xenoturbella bockii longitudinal section Xenoturbella has a very simple body plan. It consists of dorsoventrally flattened acoelomate animals, with an anterior circumferential furrow. It shows two ciliated epithelial layers: an external epidermis and an internal gastrodermis lining the simple sac-like gut. The multiciliated epiderm displays unique interconnected ciliary rootlets and mode of withdrawal and resorption of worn epidermal cells.
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Cranioplasty is an operation with a complication risk ranging from 15 to 41%. The cause for such a high risk of complication compared to other neurosurgical operations is unclear. Male patients and older patients are groups with higher rates of complication. Complications occurring after cranioplasty include bacterial infection, bone flap resorption, wound dehiscence, hematoma, seizures, hygroma, and cerebrospinal fluid (CSF) leakage.
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It is a humanized monoclonal antibody that targets sclerostin. Research shows the drug increases bone formation and decreases bone resorption in postmenopausal women with low bone density. Romosozumab was approved for medical use in Japan, the United States and the European Union in 2019. The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.
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Magnesium homeostasis comprises three systems: kidney, small intestine, and bone. In the acute phase of magnesium deficiency there is an increase in absorption in the distal small intestine and tubular resorption in the kidneys. When this condition persists, serum magnesium drops and is corrected with magnesium from bone tissue. The level of intracellular magnesium is controlled through the reservoir in bone tissue.
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Dynamins represent one of the subfamilies of GTP-binding proteins. These proteins share considerable sequence similarity over the N-terminal portion of the molecule, which contains the GTPase domain. Dynamins are associated with microtubules. They have been implicated in cell processes such as endocytosis and cell motility, and in alterations of the membrane that accompany certain activities such as bone resorption by osteoclasts.
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Although the methods of action are not yet completely understood, it is hypothesized that medication-associated osteonecrosis of the jaw is related to a defect in jaw bone healing and remodelling. The inhibition of osteoclast differentiation and function, precipitated by drug therapy, leads to decreased bone resorption and remodelling. Evidence also suggests bisphosphonates induce apoptosis of osteoclasts.Lindsay R, Cosman F. Osteoporosis.
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Bone is a highly vascular tissue, and active formation of blood vessel cells, also from mesenchymal stem cells, is essential to support the metabolic activity of bone. The balance of bone formation and bone resorption tends to be negative with age, particularly in post-menopausal women, often leading to a loss of bone serious enough to cause fractures, which is called osteoporosis.
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The protein encoded by this gene is a transmembrane glycoprotein that functions as a sulfate transporter. It is localized to the mucosa of the lower intestinal tract, particularly to the apical membrane of columnar epithelium and some goblet cells, and is instrumental in chloride reuptake, aiding in the creation of an osmotic gradient for resorption of fluid from the lumen of the intestine.
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As these frogs often live in arid and semi-arid climates, they have developed several adaptations to live months at a time away from water. These include: uricotelism, rectal water resorption, and water-loss resistant skin that changes color in response to temperature. Individual frogs can change their color from chalky white to dark brown. The brown coloration has a geometric/bark pattern.
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The radiodensity of an ameloblastoma is about 30 Hounsfield units, which is about the same as keratocystic odontogenic tumours. However, ameloblastomas show more bone expansion and seldom show high density areas. Lingual plate expansion is helpful in diagnosing ameloblastoma as cysts rarely do this. Resorption of roots of involved teeth can be seen in some cases, but is not unique to ameloblastoma.
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When looking at the radiographic features of periapical granuloma, typically there is a radiolucent lesion visible at the tip of a root on a nonvital tooth. This often is associated with root resorption. The radiolucency must correlate with the lateral root surface or the root of the tooth. The average size of radiography when looking at periapical granuloma is 7.4 millimeters (mm).
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Bone tissue (osseous tissue) is a hard tissue, a type of dense connective tissue. It has a honeycomb-like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralization of bone; osteoclasts are involved in the resorption of bone tissue.
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Crohn's disease that affects the ileum may result in an increased risk of gallstones. This is due to a decrease in bile acid resorption in the ileum, and the bile gets excreted in the stool. As a result, the cholesterol/bile ratio increases in the gallbladder, resulting in an increased risk for gallstones. Crohn's disease is associated with a type of rheumatologic disease known as seronegative spondyloarthropathy.
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The Incirrina have either a pair of rod- shaped stylets or no vestige of an internal shell, and some squid also lack a gladius. The shelled coleoids do not form a clade or even a paraphyletic group. The Spirula shell begins as an organic structure, and is then very rapidly mineralized. Shells that are "lost" may be lost by resorption of the calcium carbonate component.
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Osteoclasts are the cells responsible for the resorption of the root surface. Osteoclasts can break down bone, cartilage and dentine. Receptive activator of nuclear factor kappa-B ligand (RANKL), also called osteoclast differentiation factor (ODF) and osteoprotegerin ligand (OPGL), is a regulator of osteoclast function. In physiological bone turn over, osteoblasts and stromal cells release RANKL, this acts on macrophages and monocytes which fuse and become osteoclasts.
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The prevalence of the peripheral giant-cell granuloma is highest around 50 - 60 years of age. It appears only on the gingiva or on an edentulous alveolar ridge. It is more often found in the mandible rather than the maxilla, in either anterior or posterior areas. The underlying alveolar bone can be destroyed, leaving a unique appearance referred to as "cupping resorption" or "saucerization".
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This method usually serves as a last resort when other methods such as osteotomy and distraction osteogenesis fail to treat ankylosis. Growing state of patient is not the sole factor when deciding the treatment for an ankylosed tooth. Infraocclusion severity, bone resorption, location of the target tooth as well as dentist's preference all affect the option for treatment. Therefore, treatment for an ankylosed tooth is case-specific.
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In a healthy person, normal serum phosphate levels are maintained by the regulation of dietary absorption, bone formation and resorption, equilibration with intracellular stores, and renal excretion. When kidney function is impaired, phosphate excretion declines. Without specific treatment, hyperphosphataemia occurs almost universally, despite dietary phosphate restriction and conventional dialysis treatment. In patients on dialysis, hyperphosphataemia is an independent risk factor for fractures, cardiovascular disease and mortality.
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An osteoclast () is a type of bone cell that breaks down bone tissue. This function is critical in the maintenance, repair, and remodelling of bones of the vertebral skeleton. The osteoclast disassembles and digests the composite of hydrated protein and mineral at a molecular level by secreting acid and a collagenase, a process known as bone resorption. This process also helps regulate the level of blood calcium.
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The inorganic part of bone is the mineral hydroxyapatite, Ca10(PO4)6(OH)2. Loss of this mineral may lead to osteoporosis, as the bone is depleted for calcium if this is not supplied in the diet. OPN serves to initiate the process by which osteoclasts develop their ruffled borders to begin bone resorption. It is also found in urine, where it inhibits kidney stone formation.
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Following a single oral dose, resorption of cabergoline from the gastrointestinal (GI) tract is highly variable, typically occurring within 0.5 to 4 hours. Ingestion with food does not alter its absorption rate. Human bioavailability has not been determined since the drug is intended for oral use only. In mice and rats the absolute bioavailability has been determined to be 30 and 63 percent, respectively.
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This protein is a member of the annexin family. Members of this calcium-dependent phospholipid-binding protein family play a role in the regulation of cellular growth and in signal transduction pathways. This protein functions as an autocrine factor which heightens osteoclast formation and bone resorption. Epigenetic regulation of Annexin A2 has been identified as a key determinant of mesenchymal transformation in brain tumors.
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Pleural fluid is secreted by the parietal layer of the pleura and reabsorbed by the lymphatics in the most dependent parts of the parietal pleura, primarily the diaphragmatic and mediastinal regions. Exudative pleural effusions occur when the pleura is damaged, e.g., by trauma, infection or malignancy, and transudative pleural effusions develop when there is either excessive production of pleural fluid or the resorption capacity is reduced.
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Maximal plasma concentrations are reached 3 to 5 hours after quick and nearly complete (>90%) resorption from the gut. Plasma half life is 36 hours; the drug is effective for about 24 hours, longer than other sulfonylureas. A stable plasma level is only reached after three days of continuous application. 90% of the drug are bound to plasma proteins; at least two albumin binding sites exist.
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Rheumatologic symptoms can be improved by treatment with bisphosphonates, such as pamidronate or risedronate. Bisphosphonates inhibit osteoclastic bone resorption and therefore reduce bone remodeling and alleviate painful polyarthritis. In isolated cases, tamoxifen was effective in PDP treatment, especially for bone and joint pain. In PDP patients, high levels of nuclear receptors were found for steroids, which was the rationale to use tamoxifen, an estrogen receptor antagonist.
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Three genes that are responsible for recessive osteopetrosis in humans have been identified. They are all directly involved in the proton generation and secretion pathways that are essential for bone resorption. One gene is carbonic anhydrase II (CAII), which, when mutated, causes osteopetrosis with renal tubular acidosis(type 3). Mutations to the chloride channel ClC7 gene also lead to both dominant and recessive osteopetrosis.
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Protopteryx fossils show that they were roughly the same as a today's starling. The adult body length of Protopteryx was about , excluding the tail feathers. Protopteryx teeth were conical and unserrated, and some teeth had a resorption pit similar to those seen in Archaeopteryx. The body of Protopteryx was covered in three types of feathers: down feathers, flight feathers, and long, ribbon-like tail feathers.
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Ethanol suppresses the activity and differentiation of osteoblasts. At the same time, it has a direct effect on osteoclast activity. This results in an increased bone resorption rate and a decreased bone mineral density due to increased pit numbers and pit areas in the bone. Research has shown that viable osteocytes (another type of bone cell) may prevent osteoclastogenesis, whereas apoptotic osteocytes tend to induce osteoclast stimulation.
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TNF-α, IL-1 and IL-6 have been found to play a pivotal role in cartilage matrix degradation and bone resorption in osteoarthritis. Animal studies indicate that inflammatory cytokines may stimulate chondrocytes to release cartilage- degrading protease in osteoarthritis. This finding does not, however, necessarily translate to Homo sapiens, as osteoarthritis in humans is considered to be more complex than any animal model.
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Mineral trioxide aggregate (MTA) was developed for use as a dental root repair material by Mahmoud Torabinejad. It is formulated from commercial Portland cement, combined with bismuth oxide powder for radio-opacity. MTA is used for creating apical plugs during apexification, repairing root perforations during root canal therapy, and treating internal root resorption. This can be used for root-end filling material and as pulp capping material.
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Synthetic salmon calcitonin may be used therapeutically in humans, as it is twenty times more active than human calcitonin and has a longer half-life. It is used as therapy for Paget's disease and severe hypercalcemia. It is also used as a therapy against osteoporosis (working as an inhibitor of osteoclastic resorption), having an effectiveness of 40-50 times that of the human analogue.
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In insect anatomy, a cryptonephridium is a structure present in most larval Lepidoptera and in other insects (i.e., Coleoptera) inhabiting relatively arid environments. The Malpighian tubules are not free in the hemocele but are bound to the wall of the rectum by the perinephric membrane. This structure allows efficient resorption of water from diuresis and absorption of atmospheric water that is present in the hindgut as humidity.
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Under normal circumstances, the parathyroids secrete PTH to maintain a calcium level within normal limits, as calcium is required for adequate muscle and nerve function (including the autonomic nervous system). PTH acts on several organs to increase calcium levels. It increases calcium absorption in the bowel, while in the kidney it prevents calcium excretion and increases phosphate release and in bone it increases calcium through bone resorption.
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These is also evidence they produce increased amounts IL-1α and IL-1β which cause osteoclastic bone resorption. These amounts are greatly reduced following treatment. Studies of families, twins and sibling pairs have provided strong evidence for a genetic basis for aggressive periodontitis. A person's genetic predisposition to the condition is determined by a single gene of major effect, inherited as an autosomal dominant trait.
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Minocycline is quickly and nearly completely absorbed from the upper part of the small intestine. Taking it together with food, including milk, has no relevant influence on resorption. It reaches highest blood plasma concentrations after one to two hours and has a plasma protein binding of 70–75%. The substance penetrates into almost all tissues; very high concentrations are found in the gallbladder and liver.
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It has been shown that osteopontin and bone sialoprotein, bone matrix phosphoproteins, are highly efficient in vitro TRAP substrates, which bind to osteoclasts when phosphorylated. Upon partial dephosphorylation, both osteopontin and bone sialoprotein are incapable of binding to osteoclasts. From this effect, it has been hypothesized that TRAP is secreted from the ruffled border, dephosphorylates osteopontin and allows osteoclast migration, and further resorption to occur.
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Silicone - Silicone chin Implants are one of the most commonly used implants for chin augmentation. They are soft, smooth, flexible and come in different shapes and sizes. They do not incorporate (stick) to the surrounding tissues, so the pocket must be made precisely. They usually stay in place, but may move, buckle and cause bone resorption where they contact the mandible in some cases.
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Carbonic anhydrases are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. They show extensive diversity in tissue distribution and in their subcellular localization. The cytosolic protein encoded by this gene is predominantly expressed in the salivary glands.
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Carbonic anhydrases (CAs) are a family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. They show extensive diversity in tissue distribution and in their subcellular localization. CA5A is localized in the mitochondria and expressed primarily in the liver.
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It also induces calcium and phosphate resorption from the bone by osteoclasts. Parathyroid hormone also plays a role in activating vitamin D from its pro form to its active form. Vitamin D is also responsible for increased blood calcium levels and works in conjunction with parathyroid hormone. Vitamin D is also partly responsible for the inhibition of parathyroid hormone release by binding Vitamin D receptors at the parathyroid gland.
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These bacteria are not mediators of osteoclast activity but do cause leukocyte chemotaxis. Leukocytes differentiate into osteoclasts in the presence of lipopolysaccharide antigens found in Porphyromonas, Prevotella and Treponema species (these are all bacterial species associated with pulpal or periapical inflammation). Osteoclasts are active during bone regulation, there is constant equilibrium of bone resorption and deposition. Damage to the periodontal ligament can lead to RANKL release activating osteoclasts.
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Internal resorption defines the loss of tooth structure from within the root canal/s of a tooth. It may present initially as a pink-hued area on the crown of the tooth; the hyperplastic, vascular pulp tissue filling in the resorbed areas. This condition is referred to as a pink tooth of Mummery, after the 19th century anatomist John Howard Mummery. It may also present as an incidental, radiographic finding.
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CCL9 can activate osteoclasts through its receptor CCR1 (the most abundant chemokine receptor found on osteoclasts) suggesting an important role for CCL9 in bone resorption. CCL9 is constitutively expressed in macrophages and myeloid cells. The gene for CCL9 is located on chromosome 11 in mice. CCL9 is a chemokine involved in the process of signaling an antileukemic response and is a potential form of immunotherapy for chronic myelogenous leukemia (CML).
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One possible side effect of having KS/CHH is the increased risk of developing secondary osteoporosis or osteopenia. Oestrogen (females) or testosterone (males) is essential for maintaining bone density. Deficiency in either testosterone or oestrogen can increase the rate of bone resorption while at the same time slowing down the rate of bone formation. Overall this can lead to weakened, fragile bones which have a higher tendency to fracture.
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Fetuin-B is a protein that in humans is encoded by the FETUB gene. The protein encoded by this gene is a member of the fetuin family, part of the cystatin superfamily of cysteine protease inhibitors. Fetuins have been implicated in several diverse functions, including osteogenesis and bone resorption, regulation of the insulin and hepatocyte growth factor receptors, and response to systemic inflammation. This protein may be secreted by cells.
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However, this may give rise to serious complications such as fractures, resorption of the bone, or a flattened nasofacial angle.To prevent these complications, an implant made out of alloplastic material could be considered. Implants take less surgery time, are limitlessly available and may have more favorable characteristics than autografts. However, possible risks are rejection, infection, migration of the implant, or unpredictable changes in the physical appearance in the long term.
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This includes ruffled border Cl− permeability to control membrane potential and basolateral Cl−/HCO3− exchange to maintain cytosolic pH in physiologically acceptable ranges.> The effectiveness of its ion secretion depends upon the osteoclast forming an effective seal around the resorption compartment. The positioning of this "sealing zone" appears to be mediated by integrins expressed on the osteoclast surface. With the sealing zone in place, the multinucleated osteoclast reorganizes itself.
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Functionally, parathyroid hormone (PTH) increases calcium resorption from the bone and increases phosphate excretion from the kidney which increases serum calcium and decreases serum phosphate. Individuals with FHH, however, typically have normal PTH levels, as normal calcium homeostasis is maintained, albeit at a higher equilibrium set point. As a consequence, these individuals are not at increased risk of the complications of hyperparathyroidism. Another form has been associated with chromosome 3q.
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However, the problem is that these glucocorticoids reduce the creation of bone and induce the resorption of bone. They signal the osteoblasts and osteocytes to undergo apoptosis, or regulated cell death. The presence of adrenal steroids also acts as an indicator for potential diseases. A study was conducted observing the relationship between the level of adrenal steroid hormones with obesity among young boys aged between six and fourteen years.
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Retrieved January 15, 2009, from . Primary (baby) teeth are not replaced because they tend to become infected and to interfere with the growth of the secondary teeth. A completely avulsed tooth that is replaced within one hour of the injury can be permanently retained. The long-term retention rate decreases as the time that the tooth is detached increases, and eventually root resorption makes replacement of the tooth impossible.
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Other biomarkers that can be considered are IL-6 and receptor activator of NF-κB ligand (RANKL), which are associated with increased bone resorption in some patients. However, further investigation is needed to confirm this use of disease monitoring. Prostaglandin E2 may also be raised in patients with lung cancer and finger clubbing. This may be related to raised levels of cyclooxygenase-2, an enzyme involved in the metabolism of prostaglandins.
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Attachment of the osteoclast to the osteon begins the process. The osteoclast then induces an infolding of its cell membrane and secretes collagenase and other enzymes important in the resorption process. High levels of calcium, magnesium, phosphate and products of collagen will be released into the extracellular fluid as the osteoclasts tunnel into the mineralized bone. Osteoclasts are prominent in the tissue destruction found in psoriatic arthritis and rheumatological disorders.
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In internal resorption, root canal therapy is performed, a putty mixture of MTA is inserted in the canal using pluggers to the level of the defect. Gutta percha and root canal sealer are placed above the defect to complete the root canal treatment. In direct cases, the canal may be completely obturated with MTA. The MTA will provide structure and strength to the tooth by replacing the resorbed tooth structure.
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The kidney's resorptive mechanisms are particularly energetic, using nearly 100% of the O2 supplied. Thus, the kidney is particularly sensitive to reduction in blood supply. This phenomenon occurs because renal flow is restored prior to the normal resorption function of the renal tubule. As you can see in the graph, urine flow recovers rapidly and subsequently overshoots the typical daily output (between 800 mL and 2L in most people).
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Free OPG competitively binds to RANKL as a decoy receptor, preventing RANKL from interacting with RANK, a receptor for RANKL. The binding of RANKL to RANK (facilitated by the decreased amount of OPG available for binding the excess RANKL) stimulates osteoclast precursors, which are of a monocyte lineage, to fuse. The resulting multinucleated cells are osteoclasts, which ultimately mediate bone resorption. Estrogen also regulates this pathway through its effects on PTH.
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The authors estimated 45 to 65 total days of adult nest attendance for laying, brooding, and hatching. Varricchio et al. (2008) examined the bone histology of Two Medicine troodont specimen MOR 748 and found that it lacked the bone resorption patterns that would indicate it was an egg-laying female. They also measured the ratio of the total volume of eggs in clutches to the body mass of the adult.
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The swelling is worst at around four to six days after the injury. Extensive contusion associated with subdural hematoma is called burst lobe. Cases of a burst frontal or temporal lobe are associated with high mortality and morbidity. Old or remote contusions are associated with resorption of the injured tissue, resulting in various degrees of cavitation, in addition to the presence of a golden-yellow discoloration due to residual hemosiderin.
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The TNFRSF11A gene is present in chromosome locus 18q21.33, which encodes for the receptor activator of NF-κB (RANK). RANK is expressed in immature osteoclasts, which facilitates osteoclasts maturation upon binding of RANK ligand (RANKL). Binding of RANK ligand mediates the RANK/RANKL/OPG signalling pathway. The pathway mediates osteoclast differentiation and activation by promoting differentiation of precursors into multinucleated osteoclasts, and activating osteoclasts, thereby contributing to bone resorption and remodelling.
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Bone volume is determined by the rates of bone formation and bone resorption. Recent research has suggested that certain growth factors may work to locally alter bone formation by increasing osteoblast activity. Numerous bone-derived growth factors have been isolated and classified via bone cultures. These factors include insulin-like growth factors I and II, transforming growth factor-beta, fibroblast growth factor, platelet-derived growth factor, and bone morphogenetic proteins.
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Sachs also followed up his ophthalmoscopic examinations during the treatment by cancroine, and certified to actual resorption of a cancerous process and restoration of vision to two thirds of normal. The conditions in the breast cicatrix were also improved. The feminist and pacifist, Rosika Schwimmer, was her niece. Rosika Schwimmer's mother was also named Berta, but she was the sister of Leopold and this Berta Katscher was the wife of Leopold.
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Although the remains of over seventy individuals have been found, most of them are partial and fragmentary. The skeleton of Leedsichthys is thus only imperfectly known. This is largely caused by the fact that many skeletal elements, including the front of the skull and the vertebral centra, did not ossify but remained cartilage. Furthermore, those that did ossify were gradually hollowed out during the lifetime of the animal by resorption of the inner bone tissue.
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The periodontal ligament is a specialized connective tissue that attaches the cementum of a tooth to the alveolar bone. This tissue covers the root of the tooth within the bone. Each ligament has a width of 0.15–0.38mm, but this size decreases over time. The functions of the periodontal ligaments include attachment of the tooth to the bone, support for the tooth, formation and resorption of bone during tooth movement, sensation, and eruption.
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Osteolysis is an active resorption of bone matrix by osteoclasts and can be interpreted as the reverse of ossification. Although osteoclasts are active during the natural formation of healthy bone the term "osteolysis" specifically refers to a pathological process. Osteolysis often occurs in the proximity of a prosthesis that causes either an immunological response or changes in the bone's structural load. Osteolysis may also be caused by pathologies like bone tumors, cysts, or chronic inflammation.
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Centrifugation recreates Earth's gravitational force on the space station, in order to prevent muscle atrophy. Centrifugation can be performed with centrifuges or by cycling along the inner wall of the space station. Whole body vibration has been found to reduce bone resorption through mechanisms that are unclear. Vibration can be delivered using exercise devices that use vertical displacements juxtaposed to a fulcrum, or by using a plate that oscillates on a vertical axis.
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Once the tumor is seeded in the bone, the tumor cells stimulate bone resorption by secreting factors such as RANKL or prompting the surrounding stroma to express growth factors. These growth factors then upregulate production of RANKL which leads to osteoclastogenesis and bone destruction. The destruction of bone releases more growth factors and RANKL which induces more osteoclastogenesis, triggering a vicious cycle of bone destruction that is seen in metastatic bone tumors.
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Predicted bone growth patterns in MH1 (A and B) and A. africanus/A. afarensis (C) Growth trajectory seems to have been noticeably different in MH1 than other hominins. The nasomaxillary (bone from the nose to the upper lip) complex indicates a great degree of bone resorption, most markedly at the tooth roots of the front teeth. This contrasts with A. africanus and A. afarensis which are depository, reflecting increasing prognathism with age.
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In contrast, 16α-LE2 stimulates uterine weight, whereas 8β-VE2 has no effect, indicating that the ERα and not the ERβ is involved in the effects of estrogen on the uterus. Research has determined through experimental rodent studies with estradiol, 16α-LE2, and 8β-VE2 that the positive, protective effects of estrogens on bone formation resorption and bone mineral density are mediated via the ERα, whereas the ERβ does not appear to be involved.
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Hence, nowadays, this particular procedure is not favourable. In 1919: Armin Wald of New York City was among the first oral and maxillofacial surgeons in the United States to successfully perform the operation and publish his widely accepted procedure. In 1923: Dean claimed that his technique aim to preserve the labial cortex and contoured intraradicular bone. His technique does not include mucoperiosteal dissection and therefore, patient will experience less pain, swelling and bone resorption.
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He thus has worked on the initiation of muscle contraction, its implications for cellular electrolyte homeostasis, the control of bone resorption under both normal and osteoporotic conditions and cortical spreading depression phenomena in the central nervous system often presaging migraine headache . His current interests are directed towards mechanisms of arrhythmogenesis in genetically modified hearts, studied using biophysical, physiological and molecular biological methods and their implications for the management of atrial fibrillation and sudden cardiac death.
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PTHrP shares the same N-terminal end as parathyroid hormone and therefore it can bind to the same receptor, the Type I PTH receptor (PTHR1). PTHrP can simulate most of the actions of PTH including increases in bone resorption and distal tubular calcium reabsorption, and inhibition of proximal tubular phosphate transport. PTHrP lacks the normal feedback inhibition as PTH. However, PTHrP is less likely than PTH to stimulate 1,25-dihydroxyvitamin D production.
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Carbonic anhydrase 14 is an enzyme that in humans is encoded by the CA14 gene. Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including respiration, calcification, acid- base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. They show extensive diversity in tissue distribution and in their subcellular localization.
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Carbonic anhydrase 5B, mitochondrial is an enzyme that in humans is encoded by the CA5B gene. Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. They show extensive diversity in tissue distribution and in their subcellular localization.
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The ruffled border lies in contact with the bone surface within a resorption bay. The periphery of the ruffled border is surrounded by a ring-like zone of cytoplasm which is devoid of cell organelles but is rich in actin filaments. This zone is called clear zone or sealing zone. The actin filaments enable the cell membrane surrounding the sealing zone to be anchored firmly to the bony wall of Howship's lacunae.
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In the 1980s and 90s the physiology of typical osteoclasts was studied in detail. With the isolation of the ruffled border, ion transport across it was studied directly in biochemical detail. Energy- dependent acid transport was verified and the postulated proton pump purified. With the successful culture of osteoclasts, it became apparent that they are organized to support the massive transport of protons for acidification of the resorption compartment and solubilization of the bone mineral.
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The screw-root form design is directly threaded into bone and has macroscopic retentive elements for initial bone fixation. A direct connection between bone and the implant provides high initial stability. Over time, screw-root form designs experience bone resorption and “bone modelling and remodelling at the bone to implant interface”. Plateau-root form dental implants of 3 different sizes Plateau-root form designed implants have a different healing process to screw-root form designs.
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Ipriflavone (INN, JAN; brand name Yambolap) is a synthetic isoflavone which may be used to inhibit bone resorption, maintain bone density and to prevent osteoporosis in postmenopausal women. It is not used to treat osteoporosis. It slows down the action of the osteoclasts (bone-eroding cells), possibly allowing the osteoblasts (bone-building cells) to build up bone mass. A clinical trial reported in 2001 that it was not effective in prevention or treatment of osteoporosis.
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Arion rufus shows caudal mucous pit on its tail end. The caudal mucous pit, or caudal mucous horn, is an anatomical structure on the tail end of the foot of various land snails and slugs, terrestrial pulmonate gastropod mollusks. The function of this pit is the resorption of mucus when the gastropod is moving (see also Muratov 1999). An incorrect and yet often-used term for this structure is the "caudal gland".
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Many different materials (natural and synthetic, biodegradable and permanent) have been investigated. Most of these materials have been known in the medical field before the advent of tissue engineering as a research topic, being already employed as bioresorbable sutures. Examples of these materials are collagen and some polyesters. New biomaterials have been engineered to have ideal properties and functional customization: injectability, synthetic manufacture, biocompatibility, non-immunogenicity, transparency, nano-scale fibers, low concentration, resorption rates, etc.
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By catalyzing the hydrolysis of hyaluronan, a constituent of the extracellular matrix (ECM), hyaluronidase lowers the viscosity of hyaluronan, thereby increasing tissue permeability. It is, therefore, used in medicine in conjunction with other drugs to speed their dispersion and delivery. Common applications are ophthalmic surgery, in combination with local anesthetics. It also increases the absorption rate of parenteral fluids given by hypodermoclysis, and is an adjunct in subcutaneous urography for improving resorption of radiopaque agents.
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After the pulpotomy treatment, the radicular pulp should remain asymptomatic without any adverse clinical signs or symptoms such as sensitivity, pain, or swelling. From the radiographs, there should be absence of postoperative evidence of pathologic root resorption. There should be absence of clinical signs of infection and inflammation and no harm to the succedaneous tooth. However, radiographs play a very important role, to check if pulpotomy can be done on the primary tooth.
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For dietary purposes, vitamin E activity of vitamin E isomers is expressed as α-tocopherol equivalents (a-TEs). One a-TE is defined by the biological activity of 1 mg (natural) d-alpha-Tocopherol in the resorption-gestation test. According to listings by FAO and others beta-tocopherol should be multiplied by 0.5, gamma-tocopherol by 0.1, and a-tocotrienol by 0.3. The IU is converted to aTE by multiplying it with 0.67.
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Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. They show extensive diversity in tissue distribution and in their subcellular localization. CA IX is mainly expressed in the gastrointestinal tract where it facilitates acid secretion.
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At the same time, if rabbits are housed inside without adequate ventilation, respiratory disease can be a significant cause of illness and death. Production does on fodder are rarely able to raise more than 3 litters a year without heavy losses from deaths of weak kits, abortion, and fetal resorption, all related to poor nutrition and inadequate protein intake. In contrast, rabbits fed commercial pelleted diets can face losses related to low fiber intake.
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Most bone metastases result in osteolytic lesions, however prostate cancer causes osteoblastic lesions characterised by excess bone formation and high bone density. Prostate cancer releases cytokines such as insulin-like growth factor (IGF), endothelin-1, bone morphogenetic proteins (BMPs), sclerostin and Wnt proteins that act on local bone to increase osteoblast proliferation and activity. Wnt proteins also act on osteoblasts to upregulate OPG expression through β-catenin signalling and suppress osteoclastic bone resorption.
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Carbonic anhydrase 1 is an enzyme that in humans is encoded by the CA1 gene. Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including cellular respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. They show extensive diversity in tissue distribution and in their subcellular localization.
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In contrast with primary hyperparathyroidism in adults, primary hyperparathyroidism in children is considered a rare endocrinopathy. Pediatric primary hyperparathyroidism can be distinguished by its more severe manifestations, in contrast to the less intense manifestations in adult primary hyperparathyroidism. Multiple endocrine neoplasia is more likely to be associated with childhood and adolescent primary hyperparathyroidism. The fundamental skeletal radiologic manifestation include diffuse osteopenia, pathologic fractures and the coexistence of resorption and sclerosis at numerous sites.
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Inflammation, erythema, pain and increased skin temperature (3–7 degrees Celsius) around the joint may be noticeable on examination. X-rays may reveal bone resorption and degenerative changes in the joint. These findings in the presence of intact skin and loss of protective sensation are pathognomonic of acute Charcot arthropathy. Roughly 75% of patients experience pain, but it is less than what would be expected based on the severity of the clinical and radiographic findings.
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Although some research suggest palatal tori to be an autosomal dominant trait, it is generally believed that palatal tori are caused by several factors. They are more common in early adult life and can increase in size. In some older people, the size of the tori may decrease due to bone resorption. It is believed that tori of the lower jaw are the result of local stresses and not due solely to genetic influences.
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An ostium secundum that persists at large size can be a source of atrial septal defects. Foramen secundum atrial septal defects are the most common atrial septal defects. This defect can arise as a result of defects of the septum primum and the septum secundum. For the septum primum, the problem can arise as a result of excess resorption of the septum during the process of apoptosis in order to form the foramen secundum.
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Evidence suggests that bone cells produce growth factors for extracellular storage in the bone matrix. The release of these growth factors from the bone matrix could cause the proliferation of osteoblast precursors. Essentially, bone growth factors may act as potential determinants of local bone formation. Research has suggested that cancellous bone volume in postmenopausal osteoporosis may be determined by the relationship between the total bone forming surface and the percent of surface resorption.
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TRAP is associated with osteoclast migration to bone resorption sites, and, once there, TRAP is believed to initiate osteoclast differentiation, activation, and proliferation. This hypothesis was formed from the examination of the bone structure of TRAP-null mice. It was noted that, in addition to osteopetrosis, bone formation occurred in a haphazard manner, where the microarchitecture was highly irregular. In TRAP overexpressing mice, it has been found that the affected mice are grossly obese.
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Since about 2002, some patients with this disorder have been offered drug therapy with bisphosphonates (a class of osteoporosis drugs) to treat problems with bone resorption associated with the bone breakdown and skeletal malformations that characterize this disorder. Brand names include Actonel (risedronate/alendronate), made by Merck Pharmaceuticals. Other drugs include Pamidronate, made by Novartis and Strontium Ranelate, made by Eli Lilly. However, for more progressive cases, surgery and bone grafting are necessary.
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In the periapical lesion, mediators that are normally produced primarily only by osteoblasts are released by many other cells as well, overstimulating proosteoclasts. As a result, these begin to proliferate and several cells fuse to form multinucleated giant cells capable of spreading over the infected, injured site and cause resorption of the periapical alveolar bone.Nair, PNR: Pathobiology of the Periapex. In Cohen, S. Burns, RC, editors: Pathways of the Pulp, 8th Edition.
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The alveolar bone is the bone of the jaw which forms the alveolus around teeth. Like any other bone in the human body, alveolar bone is modified throughout life. Osteoblasts create bone and osteoclasts destroy it, especially if force is placed on a tooth. As is the case when movement of teeth is attempted through orthodontics, an area of bone under compressive force from a tooth moving toward it has a high osteoclast level, resulting in bone resorption.
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Periodontal disease is caused by inflammation of the gums and the supporting tissue due to dental plaque. Periodontal disease is commonly caused by a build up of plaque on the teeth which contain specific pathological bacteria. They produce an inflammatory response that has a negative effect on the bone and supporting tissues that hold your teeth in place. One of the effects of periodontal disease is that it causes bone resorption and damage to the supportive tissues.
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Inflamm Bowel Dis Volume 13, Number 12, December 2007 Adequate disease control usually improves anemia of chronic disease, but iron deficiency may require treatment with iron supplements. Guidelines vary as to how iron should be administered. Besides other, problems include a limitation in possible daily resorption and an increased growth of intestinal bacteria. Some advise parenteral iron as first line as it works faster, has fewer gastrointestinal side effects, and is unaffected by inflammation reducing enteral absorption.
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Apparently, the sacrum preserves six vertebrae, with elongated transverse processes. For instance, its pelvis is very particular compared to other therizinosaur relatives, featuring areas of bone resorption and bone remodeling on the illium. These specific traits may indicate the advanced age of the individual, if true, the fusion of the obturator process and pubic body could be discarded as an authentic autapomorphy for the species. Zanno noted that more analyses are required to settle this enigma.
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As the body attempts to clean up these wear particles (typically consisting of plastic or metal), it triggers an autoimmune reaction which causes resorption of living bone tissue. Osteolysis has been reported to occur as early as 12 months after implantation and is usually progressive. This may require a revision surgery (replacement of the prosthesis). Although osteolysis itself is clinically asymptomatic, it can lead to implant loosening or bone breakage, which in turn causes serious medical problems.
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The original bisphosphonates (first generation) were simple molecules with small groups of single atoms or alkyl chains in position R1 and R2. They only had a rather weak inhibiting effect on bone resorption. The inclusion of an amino group marked the beginning of the second generation of bisphosphonates with higher potency. The first was pamidronate and similar analogues followed where the position of the nitrogen in the side chain was the key to a more potent drug.
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Dentin forms the bulk of the tooth substance, and contributes most to the overall tooth color. At the core of the tooth is soft connective tissue termed the dental pulp. The pulp is pink/red due to its vascularity, but is rarely visible through the overlying enamel and dentin unless the thickness of these layers is reduced by tooth wear (or rarely internal resorption). Public opinion of what is normal tooth shade tends to be distorted.
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Polymers such as some microporous grades of PMMA and various other acrylates (such as polyhydroxylethylmethacrylate aka PHEMA), coated with calcium hydroxide for adhesion, are also used as alloplastic grafts for their inhibition of infection and their mechanical resilience and biocompatibility. Calcifying marine algae such as Corallina officinalis have a fluorohydroxyapatitic composition whose structure is similar to human bone and offers gradual resorption, thus it is treated and standardized as "FHA (Fluoro-hydroxy-apatitic) biomaterial" alloplastic bone grafts.
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Parafollicular cells secrete calcitonin, a hormone that participates in the regulation of calcium metabolism. Calcitonin lowers blood levels of calcium by inhibiting the resorption of bone by osteoclasts, and its secretion is increased proportionally with the concentration of calcium. Parafollicular cells are also known to secrete in smaller quantities several neuroendocrine peptides such as serotonin, somatostatin or CGRP. They may also have a role in regulating thyroid hormones production locally, as they express thyrotropin-releasing hormone.
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If rampant caries is a result of previous radiation to the head and neck, it may be described as radiation-induced caries. Problems can also be caused by the self-destruction of roots and whole tooth resorption when new teeth erupt or later from unknown causes. Children at 6–12 months are at increased risk of developing dental caries. For other kids aged 12–18 months, dental caries develop on primary teeth and approximately twice yearly for permanent teeth.
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He also had markedly delayed skeletal maturation (bone age 15 years), a severely undermineralized skeleton, evidence of increased bone resorption, and very early-onset osteoporosis. The genitalia, testes, and prostate of the patient were all normal and of normal size/volume. The sperm count of the patient was normal (25 million/mL; normal, >20 million/mL), but his sperm viability was low (18%; normal, >50%), indicating some degree of infertility. The patient also had early-onset temporal hair loss.
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Osteoclasts are regulated by several hormones, including parathyroid hormone (PTH) from the parathyroid gland, calcitonin from the thyroid gland, and growth factor interleukin 6 (IL-6). This last hormone, IL-6, is one of the factors in the disease osteoporosis, which is an imbalance between bone resorption and bone formation. Osteoclast activity is also mediated by the interaction of two molecules produced by osteoblasts, namely osteoprotegerin and RANK ligand. Note that these molecules also regulate differentiation of the osteoclast.
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This technique increases the malleability of the crestal bone and uses not the bone directly below the sinus, but rather the bone on the medial wall, and thus can be used in more extreme cases of bone resorption that would normally need to be treated with the lateral wall technique. The healing period is reduced to 1.5 to 3 months. Recently an electrical mallet has been introduced to simplify the application of this and similar techniques.
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Though male European rabbits may sometimes be amicable with one another, fierce fights can erupt among bucks during the breeding season, typically January to August. A succession of litters (usually 3-7 kittens each) are produced, but in overpopulated areas, pregnant does may lose all their embryos through intrauterine resorption. Shortly before giving birth, the doe will construct a separate burrow known as a "stop" or "stab", generally in an open field away from the main warren.
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After extraction of a tooth, the clot in the alveolus fills in with immature bone, which later is remodeled into mature secondary bone. Disturbance of the blood clot can cause alveolar osteitis, commonly referred to as "dry socket." With the partial or total loss of teeth, the alveolar process undergoes resorption. The underlying basal bone of the body of the maxilla or mandible remains less affected, however, because it does not need the presence of teeth to remain viable.
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Ferric sulphate is used to arrest pulpal bleeding by forming a sealing membrane through the agglutination of the blood proteins with ferric and sulfate ions. This metal-protein clot at the surface of the pulp may act as a barrier to external irritants. The physiological clot formation is thought to be able to minimise inflammation and internal resorption compared to calcium hydroxide. Most importantly, ferric sulphate causes minimal devitalization and subsequent preservation of the pulp tissue.
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This "classical" PTH receptor is expressed in high levels in bone and kidney and regulates calcium ion homeostasis through activation of adenylate cyclase and phospholipase C. In bone, it is expressed on the surface of osteoblasts. When the receptor is activated through PTH binding, osteoblasts express RANKL (Receptor Activator of Nuclear Factor kB Ligand), which binds to RANK (Receptor Activator of Nuclear Factor kB) on osteoclasts. This turns on osteoclasts to ultimately increase the resorption rate.
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The lower canines are shed at nine to twelve years. The upper and lower first molars are shed at nine to eleven years. The upper and lower second molars are shed at ten to twelve years. The erupting permanent teeth cause root resorption, where the permanent teeth push on the roots of the primary teeth, causing the roots to be dissolved by odontoclasts (as well as surrounding alveolar bone by osteoclasts) and become absorbed by the forming permanent teeth.
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Wood currently works as a Research Ecologist for the U.S. Forest Service. She also works for the Tropical Responses to Altered Climate Experiment as the first on-site scientist and leads research under the ground. Her graduate research was focused around the importance and effects of litter in tropical forests. It culminated with her thesis, The importance of litter to ecosystem function in a wet tropical forest; Environmental and physiological controls on nutrient resorption of nine tropical tree species.
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In especially severe cases of OFC, parathyroidectomy, or the full removal of the parathyroid glands, is the chosen route of treatment. Parathyroidectomy has been shown to result in the reversal of bone resorption and the complete regression of brown tumors. In situations where parathyroid carcinoma is present, surgery to remove the tumors has also led to the regression of hyperparathyroidism as well as the symptoms of OFC. Bone transplants have proven successful in filling the lesions caused by OFC.
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Also, clastic cells are cells that cause mineralized tissue resorption. If there is an unbalance of clastic cell, this will disrupt resorptive activity and cause diseases. One of the studies involving mineralized tissues in dentistry is on the mineral phase of dentin in order to understand its alteration with aging. These alterations lead to “transparent” dentin, which is also called sclerotic. It was shown that a ‘‘dissolution and reprecipitation’’ mechanism reigns the formation of transparent dentin.
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If this happens, parents should be advised of possible complications such as enamel hypoplasia, hypocalcification, crown/root dilaceration, or disruptions in tooth eruption sequence. Potential sequelae can involve pulpal necrosis, pulp obliteration and root resorption. Necrosis is the most common complication and an assessment is generally made based on the colour supplemented with radiograph monitoring. A change in colour may mean that the tooth is still vital but if this persists it is likely to be non-vital.
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In another retrospective analysis of 202 patients with ectopic PA, intra-thyroidal location was found in 18 % of the cases. Intra-thyroid parathyroid adenomas mimic thyroid nodules in CT scans and may even show uptake on a thyroid iodine scan. Correlation with laboratory workup, including measurement of serum parathyroid hormone and calcium level, is required. In addition, the evaluating radiologist should search for radiological manifestations of hyperparathyroidism, such as osteopenia, bone resorption, and brown tumours (Fig. 22). Fig. 22.
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To prevent bone resorption without affecting too much bone calcification, etidronate must be administered only for a short time once in a while, for example for two weeks every 3 months. When given on a continuous basis, say every day, etidronate will altogether prevent bone calcification. This effect may be useful and etidronate is in fact used this way to fight heterotopic ossification. But in the long run, if used on a continuous basis, it will cause osteomalacia.
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Since women can have signs and symptoms that could be attributed to other causes, diagnosis is based upon the symptoms that cannot be better accounted for by another diagnosis. Lab tests usually do not provide information that will aid in diagnosing. A visual exam is useful. The observations of the following may indicate lower estrogen levels: little pubic hair, loss of the labial fat pad, thinning and resorption of the labia minora, and the narrowing of the vaginal opening.
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Thus, vitamin D is also critical for bone remodeling through its role as a potent stimulator of bone resorption. The VDR regulates cell proliferation and differentiation. Vitamin D also affects the immune system, and VDRs are expressed in several white blood cells, including monocytes and activated T and B cells. In vitro, vitamin D increases expression of the tyrosine hydroxylase gene in adrenal medullary cells, and affects the synthesis of neurotrophic factors, nitric oxide synthase, and glutathione.
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The effector organs of the first homeostatic mechanism are the bones, the kidney, and, via a hormone released into the blood by the kidney in response to high PTH levels in the blood, the duodenum and jejunum. Parathyroid hormone (in high concentrations in the blood) causes bone resorption, releasing calcium into the plasma. This is a very rapid action which can correct a threatening hypocalcemia within minutes. High PTH concentrations cause the excretion of phosphate ions via the urine.
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An overdenture is a denture, the base of which covers one or more teeth, prepared roots or implants. An overdenture is usually used for elderly patients that have lost some teeth but not all, rendering them suitable for a set of full dentures. The overdenture is not rigid in the mouth; it is removable. An advantage of overdentures compared to full dentures is that the roots left in the maxilla (upper jaw) help preserve bone of the upper jaw, preventing bone resorption.
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Although retention of a root prevents the alveolar bone from resorbing, at a distant site from the overdenture abutment the bone is susceptible to gradual resorption. This could lead to instability of the denture and uneven loading over time. There is then a potential for the denture to irritate the mucosa due to repeated movement against the tissues. Denture Stomatitis Denture stomatitis is a common problem in full and partial denture wearers, and so can also be seen in patients wearing overdentures.
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These crystals cause an inflammatory response and can lead to the occlusion of smaller vessels. Further complications like secondary infections and necrosis can develop from this and can be fatal for some, making the monitoring of blood calcium and phosphate levels necessary. Conditions due to bone loss such as osteopenia and osteoporosis are common in tertiary hyperparathyroidism along with pathologic fractures. Pseudoclubbing of the digits can also be indicative of a severe tertiary hyperparathyroidism due to excess resorption at the distal phalanges.
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Bisphosphonates mimic the endogenous inorganic pyrophosphate where the oxygen backbone is replaced with carbon (P-C-P for P-O-P). The two additional groups or side chains on the carbon backbone are usually referred to as R1 and R2. R1 is usually a hydroxyl group which enhances the affinity for the calcium by forming a tridentate ligand along with the phosphate groups. The compound can be made more potent by optimizing the structure of the R2 group to best inhibit bone resorption.
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As bone resorption fails while bone formation continues, excessive bone is formed.Robbins Basic Pathology by Kumar, Abbas, Fausto, and Mitchell, 8th edition Mutations in at least nine genes cause the various types of osteopetrosis. Mutations in the CLCN7 gene are responsible for about 75 percent of cases of autosomal dominant osteopetrosis, 10 to 15 percent of cases of autosomal recessive osteopetrosis, and all known cases of intermediate autosomal osteopetrosis. TCIRG1 gene mutations cause about 50 percent of cases of autosomal recessive osteopetrosis.
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To reverse peri-implant mucositis, good oral hygiene must be performed regularly to remove plaque which initiated this disease. Peri-implant mucositis becomes peri-implantitis when bone resorption is identified around the implant on a radiograph as well as all the signs associated with peri-implant mucositis is seen. Often, pus may also exude from the tissues surrounding the implant. However, mobility of the implant is not a sign of peri-implantitis as this disease begins at the margins of the implant.
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Cathepsin K has an optimal enzymatic activity in acidic conditions. It is synthesized as a proenzyme with a molecular weight of 37kDa, and upon activation by autocatalytic cleavage, is transformed into the mature, active form with a molecular weight of ~27kDa. Upon polarization of the osteoclast over the site of resorption, cathepsin K is secreted from the ruffled border into the resorptive pit. Cathepsin K transmigrates across the ruffled border by intercellular vesicles and is then released by the functional secretory domain.
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It is shown to have less marginal gap formation, less leakage and better adaptation than other filling materials. Besides, root ends filled with MTA showed good healing with absence of periradicular inflammation over the root-end filling material, as compared to amalgam. The use of MTA as endodontic repair material stimulates bone formation as well as inhibits bone resorption. Due to its physical properties and biocompatibility, MTA has been used in numerous clinical situations other than as a root-end filling.
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McCleave et al. (1987) suggested that hatching peaks in February and may continue until April. Wang and Tzeng (2000) proposed, on the basis of otolith back- calculations, that hatching occurs from March to October and peaks in August. However, Cieri and McCleave (2000) argued that these back-calculated spawning dates do not match collection evidence and may be explained by resorption. Fecundity for many eels is between about 0.5 to 4.0 million eggs, with larger individuals releasing as many as 8.5 million eggs.
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Radiolucency around a 12 day old scaphoid fracture that was initially barely visible. CC-BY 3.0 Seven to nine days after fracture, the cells of the periosteum replicate and transform. The periosteal cells proximal to (on the near side of) the fracture gap develop into chondroblasts, which form hyaline cartilage. The periosteal cells distal to (at the far end of) the fracture gap develop into osteoblasts, which form woven bone through bone resorption of calcified cartilage and recruitment of bone cells and osteoclasts.
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Several studies have proposed that bisphosphonates cause excessive reduction of bone turnover, resulting in a higher risk of bone necrosis when repair is needed. It is also thought that bisphosphonates bind to osteoclasts and interfere with the remodeling mechanism in bone. To be more specific, the drug interferes with the cholesterol biosynthesis pathway through the inhibition of farnesyl diphosphate synthase. Over time, the cytoskeleton of the osteoclasts loses its function and the essential border needed for bone resorption does not form.
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In: Am J Physiol. 1997 Feb;272(2 Pt 1):C697-706. doi:10.1152/ajpcell.1997.272.2.C697, At the same time, the first of two steps for endogenous creatine synthesis takes place in the kidneys themselves. Patients with kidney disease and those undergoing dialysis treatment generally show significantly lower levels of creatine in their organs, since the pathological kidneys are both hampered in creatine synthesis capability and are in back-resorption of creatine from the urine in the distal tubules.
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However, there are alternative explanations for the thin eggshell not dependent on pathology. Later researchers found resorption craters in the basal caps at the base of the columns, meaning that the eggs hatched. Some researchers postulated that the thinner "Hypselosaurus priscus" eggshells came from different taxa than the thicker eggshells, and subsequent researchers have come to support this idea. Another potential explanation for variation in eggshell thickness is that the thinner eggs were laid by younger individuals than older ones.
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Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. They show extensive diversity in tissue distribution and in their subcellular localization. CA IV is a glycosylphosphatidyl-inositol-anchored membrane isozyme expressed on the luminal surfaces of pulmonary (and certain other) capillaries and of proximal renal tubules.
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Plasma calcium levels in mammals are tightly regulated, electronic-book electronic- with bone acting as the major mineral storage site. Calcium ions, Ca2+, are released from bone into the bloodstream under controlled conditions. Calcium is transported through the bloodstream as dissolved ions or bound to proteins such as serum albumin. Parathyroid hormone secreted by the parathyroid gland regulates the resorption of Ca2+ from bone, reabsorption in the kidney back into circulation, and increases in the activation of vitamin D3 to calcitriol.
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Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts. Both processes utilize cytokine (TGF-β, IGF) signalling. Bone remodeling (or bone metabolism) is a lifelong process where mature bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation). These processes also control the reshaping or replacement of bone following injuries like fractures but also micro-damage, which occurs during normal activity.
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This module utilizes two species of Tetrahymena: Tetrahymena thermophilia and Tetrahymena vorax. In the lab, an extract, called stomatin, is made from the thermophilia, then placed into the vorax culture. There, it induces a transformation from the microstome form to the macrostome form in T. vorax. This transformation is most notable by a marked increase in the size of the cell (doubling or sometimes more), the resorption of the microstomal oral apparatus and the construction of a much larger macrostomal oral apparatus.
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Primary enamel cuticle, also called Nasmyth's membrane, is thin membrane of tissue also known as reduced enamel epithelium (REE) produced by the ameloblast, that covers the tooth once it has erupted. This tissue is primarily basal lamina. It is usually worn away by mastication and cleaning. The primary enamel cuticle protects enamel from resorption by cells of the dental sac and also secretes desmolytic enzymes for elimination of the dental sac, allowing fusion between reduced enamel epithelium and oral epithelium.
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49 The metarhyolite making up much of the formation is reddish orange in color, but ranges from brick red to light pink. It includes relict phenocrysts of quartz and microcline and most outcrops show drag-folded flow bands. Some outcrops contain relict phenocrysts of albite- oligoclase. All of the phenocrysts have been reoriented about axes parallel to that of the drag-folded flow bands. Phenocryst size is from 0.02 to over 5 mm but typically 0.5 mm and show resorption or recrystallization to aggregates of smaller grains.
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Once diagnosed, the gap in the temporal bone can be repaired by surgical resurfacing of the affected bone or plugging of the superior semicircular canal. These techniques are performed by accessing the site of the dehiscence either via a middle fossa craniotomy or via a canal drilled through the transmastoid bone behind the affected ear. Bone cement has been the material most often used, in spite of its tendency to slippage and resorption, and a consequent high failure rate; recently, soft tissue grafts have been substituted.
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The tissues of the mouth, including the tongue, gingiva, teeth and soft palate are commonly involved in Parry–Romberg syndrome. 50% of affected individuals develop dental abnormalities such as delayed eruption, dental root exposure, or resorption of the dental roots on the affected side. 35% have difficulty or inability to normally open the mouth or other jaw symptoms, including temporomandibular joint disorder and spasm of the muscles of mastication on the affected side. 25% experience atrophy of one side of the upper lip and tongue.
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The modern day olive colobus monkey may have had a similar diet to A. sediba (which markedly contrasts with typical early hominin diets), and appears to have similar patterns of facial-bone growth, which may indicate diverging resorptions and deposition patterns in A. sediba from other hominins reflects different jaw-loading patterns. The margins of the eye sockets of MH1 are curved, whereas they are indented in A. africanus, which may indicate bone deposition in A. sediba in regions where bone resorption occurs in A. africanus.
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Patients may develop periorbital ecchymosis ("raccoon eyes"). Patients with subgaleal hematoma may present with hemorrhagic shock given the volume of blood that can be lost into the potential space between the skull periosteum and the scalp galea aponeurosis, which has been found to be as high as 20-40% of the neonatal blood volume in some studies. The swelling may obscure the fontanel and cross cranial suture lines, (distinguishing it from cephalohematoma). Patients with subgaleal hemorrhage may also have significant hyperbilirubinemia due to resorption of hemolyzed blood.
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RANKL, through its ability to stimulate osteoclast formation and activity, is a critical mediator of bone resorption and overall bone density. Overproduction of RANKL is implicated in a variety of degenerative bone diseases, such as rheumatoid arthritis and psoriatic arthritis. In addition to degenerative bone diseases, bone metastases can also induce pain and other abnormal health complexities that can significantly reduce a cancer patient’s quality of life. Some examples of these complications that are a consequence of bone metastasis are: hypercalcemia, pathological fractures and spinal cord compression.
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In developed countries, the average birth weight of a full-term newborn is approximately , and is typically in the range of . Over the first 5–7 days following birth, the body weight of a term neonate decreases by 3–7%, and is largely a result of the resorption and urination of the fluid that initially fills the lungs, in addition to a delay of often a few days before breastfeeding becomes effective. After the first week, healthy term neonates should gain 10–20 grams/day.
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Hip dysplasia is often cited as causing osteoarthritis of the hip at a comparatively young age. Dislocated load bearing surfaces lead to increased and unusual wear, although there are studies that contradict these findings (see ). Peri-acetabular osteotomy (PAO) surgery can be used to realign the hip joint in some adolescents and adults. Subsequent treatment with total hip arthroplasty (hip replacement) is complicated by a need for revision surgery (replacing the artificial joint) owing to skeletal changes as the body matures, loosening/wear or bone resorption.
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The body size of children may be not enough to have bone flaps to be stored in their subcutaneous spaces, while cryopreservation facilities for bone grafts are not widely available. The use of autograft is also associated with a high rate of bone resorption. Synthetic materials are used for paediatric cranioplasty when the use of autografts is not available or not recommended. Hydroxyapatite is another option for children cranioplasty as it allows the expansion of cranium for children and its ability to be moulded smoothly.
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V-ATPases in the osteoclast plasma membrane pump protons onto the bone surface, which is necessary for bone resorption. In the intercalated cells of the kidney, V-ATPases pump protons into the urine, allowing for bicarbonate reabsorption into the blood. In addition, other variety of biological processes, such as toxin delivery, viral entry, membrane targeting, apoptosis, regulation of cytoplasmic pH, proteolytic process, and acidification of intracellular systems, are important roles of V-ATPases. V-ATPases also play a significant role in cell morphogenesis development.
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Eggs hatch on the female's back as froglets, without free-living larval stage. Juveniles stay on their mother's back until they are about in length, although smaller ( SVL) independent juveniles can also be found. It is speculated that the juveniles leave their mother's back when the resorption of the gill stalks is complete, coinciding with the consumption of all yolk. Juveniles may leave their mother also prematurely, showing residual gill stalks and yolk in their bellies, in response to stress caused by handling or predation.
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Patients may present with features of hypocalcaemia including carpo-pedal muscular spasms, cramping, tetany, and if the calcium deficit is severe, generalized seizures. IQ is typically mildly depressed or unaffected. Additional characteristics include short stature, obesity, developmental delay, and calcification of the basal ganglia in the deep white matter of the brain. Type 1a Pseudohypoparathyroidism is clinically manifest by bone resorption with blunting of the fourth and fifth knuckles of the hand, most notable when the dorsum of the hand is viewed in closed fist position.
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Osteomalacia is a disease characterized by the softening of the bones caused by impaired bone metabolism primarily due to inadequate levels of available phosphate, calcium, and vitamin D, or because of resorption of calcium. The impairment of bone metabolism causes inadequate bone mineralization. Osteomalacia in children is known as rickets, and because of this, use of the term "osteomalacia" is often restricted to the milder, adult form of the disease. Signs and symptoms can include diffuse body pains, muscle weakness, and fragility of the bones.
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The protein encoded by this gene, a member of the claudin family, is an integral membrane protein and a component of tight junction strands. It is found primarily in the kidneys, specifically in the thick ascending limb of Henle, where it acts as either an intercellular pore or ion concentration sensor to regulate the paracellular resorption of magnesium ions. Defects in this gene are a cause of primary hypomagnesemia, which is characterized by massive renal magnesium wasting with hypomagnesemia and hypercalciuria, resulting in nephrocalcinosis and kidney failure.
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Even with the most meticulous chlorine-washings there seemed to be an unavoidable mortality rate of about 1 percent. He therefore suggested that self-infection took place - that internally generated cadaveric particles were responsible, for instance tissue crushed in the birth process and eventually turning gangrenous. Most of the objections from Semmelweis's critics stemmed from his claim that every case of childbed fever was caused by resorption of cadaveric particles. Some of Semmelweis's first critics even responded that he had said nothing new - it had long been known that cadaveric contamination could cause childbed fever.
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Gorham's disease (pronounced GOR-amz), also known as Gorham vanishing bone disease and phantom bone disease, is a very rare skeletal condition of unknown cause, characterized by the uncontrolled proliferation of distended, thin- walled vascular or lymphatic channels within bone, which leads to resorption and replacement of bone with angiomas and/or fibrosis.Gorham LW, Stout AP. Massive osteolysis (acute spontaneous absorption of bone, phantom bone, disappearing bone): its relation to hemangiomatosis. J Bone Joint Surg [Am] 1955;37-A:985-1004.Ross JL., Schinella R., and Shenkman L. Massive osteolysis: An unusual cause of bone destruction.
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While bone resorption is commonly associated with many diseases or joint problems, the term osteolysis generally refers to a problem common to artificial joint replacements such as total hip replacements, total knee replacements and total shoulder replacements. Osteolysis can also be associated with the radiographic changes seen in those with bisphosphonate- related osteonecrosis of the jaw. There are several biological mechanisms which may lead to osteolysis. In total hip replacement, the generally accepted explanation for osteolysis involves wear particles (worn off the contact surface of the artificial ball and socket joint).
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A related condition, bisphosphonate-associated osteonecrosis of the jaw (BON), has been described as a side-effect of amino- bisphosphonates, a class of phosphorus-based drugs that inhibit bone resorption and are used widely for treating osteoporosis, bone disease in cancer and some other conditions. BON, sometimes called "bis-phossy jaw", is primarily associated with the use of intravenous bisphosphonates in the treatment of cancer. The percentage incidence of BON from this use is approximately 1000 times higher than the incidence of BON caused by the use of oral bisphosphonates.
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Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. They show extensive diversity in tissue distribution and in their subcellular localization. CA XI is likely a secreted protein, however, radical changes at active site residues completely conserved in CA isozymes with catalytic activity, make it unlikely that it has carbonic anhydrase activity.
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Patients who are placed on a 6-month drug holiday exhibit marked improvements in their serum CTX values; in one study, patients showed an improvement of 155.3 pg/mL over 6 months or a rate of 25.9 pg/mL each month. Initially, urinary CTX levels were sought, but this proved to offer no greater value than urinary NTX values—both tests suffered from large spontaneous fluctuations unrelated to therapy or intervention, and were therefore largely unreliable.Ju, H, et al. _Comparison of analytical performance and biological variability of three bone resorption assays_.
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Eating or fasting prior to taking a blood sample has an effect on analyses for glucose in the blood; a high fasting glucose blood sugar level may be a sign of prediabetes or diabetes mellitus. The glycemic index is an indicator of the speed of resorption and conversion to blood glucose levels from ingested carbohydrates, measured as the area under the curve of blood glucose levels after consumption in comparison to glucose (glucose is defined as 100).Richard A. Harvey, Denise R. Ferrier: Biochemistry. 5th Edition, Lippincott Williams & Wilkins, 2011, , p. 366.
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Most therapies that target the RANK/RANKL/OPG axis aim to either down-regulate expression of RANKL or upregulate the expression of the decoy receptor OPG. For example, denosumab is a fully human monoclonal antibody that is directed against RANKL. In phase I and II trials, denosumab led to a decrease in bone resorption in multiple myeloma, prostate cancer and breast cancer patients. Another study looked into developing small mimetics based on the structure of OPG that bind to RANK as well as RANKL and cause defective coupling between the two.
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The common function which applies to all bisphosphonate drugs is a physicochemical interaction with the bone mineral to prevent the physical resorption of the bone by the osteoclasts. This is especially relevant at sites where bone remodelling is most active. The bisphosphonates have an intrinsic affinity for the calcium ions (hydroxyapatite) of the bone mineral just as the endogenous pyrophosphates. The difference lies in the non- hydrolysable carbon-phosphorus bond of the bisphosphonates which prevents their metabolism and at the same time ensure an effective absorption from the gastrointestinal tract.
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The toxicity of metal carbonyls is due to toxicity of carbon monoxide, the metal, and because of the volatility and instability of the complexes, any inherent toxicity of the metal is generally made much more severe due to ease of exposure. Exposure occurs by inhalation, or for liquid metal carbonyls by ingestion or due to the good fat solubility by skin resorption. Most clinical experience were gained from toxicological poisoning with nickel tetracarbonyl and iron pentacarbonyl due to their use in industry. Nickel tetracarbonyl is considered as one of the strongest inhalation poisons.
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This causes age to be significantly underestimated. Over the lifespan of an individual, bone is constantly being reconstructed as specialised cells remove and deposit bone leading to a constant renewal of the bone material. The continuous resorption and deposition leaves gaps in the record of growth and missing bone tissue is a case at any stage of a vertebrate’s life cycle; ‘complete specimens that allow precise identification are extremely rare’. Therefore, to account for any missing bone tissues in a specimen, retrocalculation of skeletal age is to be completed.
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During this stage, use of teeth and normal tooth replacement likely ceased or became reduced, since none of the still-erupted teeth bear any wear marks or resorption. As the specimens grew, the transformation became more radical. In subadult and adult specimens older than one year, all the teeth were missing. CT scanning shows that only five empty tooth sockets remained in the adult maxilla; all the sockets in the lower jaw were fused into a single, hollow canal, and the rest of the tooth sockets were obliterated.
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This surface-bound molecule (also known as CD254), found on osteoblasts, serves to activate osteoclasts, which are critically involved in bone resorption. Osteoclastic activity is triggered via the osteoblasts' surface-bound RANKL activating the osteoclasts' surface-bound receptor activator of nuclear factor kappa-B (RANK). Recent studies suggest that in postnatal bones, the osteocyte is the major source of RANKL regulating bone remodeling. RANKL derived from other cell types contributes to bone loss in conditions involving inflammation such as rheumatoid arthritis, and in lytic lesions caused by cancer, such as in multiple myeloma.
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In addition, vitamin A1-deprived but all-trans-retinoic acid-supplemented male rats exhibit hypogonadism and infertility due to lack of local retinoic acid synthesis in the testis; similar treatment of female rats causes infertility due to fetal resorption caused by a lack of local retinoic acid synthesis in the embryo. The retinoic acid synthesis in testes is catalyzed primarily by the RALDH2 (ALDH1A2) aldehyde dehydrogenase. Suppressing this enzyme has been proposed as a possible way to make a male contraceptive pill, because retinoic acid is necessary for spermatogenesis in humans, much as in rats.
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This idea may have been superseded by a further recent theory. This new theory proposes firstly that areas of tension and compression are generated in the soft tissues surrounding unerupted teeth by the distribution of bite forces through the jaws. These patterns of tension and compression, are further proposed to result in patterns of bone resorption and deposition that lift the tooth into the mouth. This theory is based on Wolff's Law, which is the long established idea that bone changes shape in accordance with the forces applied.
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Thrombosis of the sinuses is the main mechanism behind the increase in intracranial pressure due to decreased resorption of cerebrospinal fluid (CSF). The condition does not lead to hydrocephalus, however, because there is no difference in pressure between various parts of the brain. Any blood clot forms due to an imbalance between coagulation (the formation of the insoluble blood protein fibrin) and fibrinolysis. The three major mechanisms for such an imbalance are enumerated in Virchow's triad: alterations in normal blood flow, injury to the blood vessel wall, and alterations in the constitution of blood (hypercoagulability).
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Recent works on the morphological changes of the mandible during development have shown that the human chin, or at least the inverted-T shaped mental region, develops during the prenatal period, but the chin does not become prominent until the early postnatal period. This later modification happens by bone remodeling processes (bone resorption and bone deposition). Coquerelle et al. show that the anteriorly positioned cervical column of the spine and forward displacement of the hyoid bone limit the anterior–posterior breadth in the oral cavity for the tongue, laryngeal, and suprahyoid musculatures.
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Venous sinus stenoses leading to venous hypertension appear to play a significant part in relation to raised ICP, and stenting of a transverse sinus may resolve venous hypertension, leading to improved CSF resorption, decreased ICP, cure of papilledema and other symptoms of IIH. A self-expanding metal stent is permanently deployed within the dominant transverse sinus across the stenosis under general anaesthesia. In general, people are discharged the next day. People require double antiplatelet therapy for a period of up to 3 months after the procedure and aspirin therapy for up to 1 year.
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The large intestine primarily serves as a site for fermentation of indigestible matter by gut bacteria and for resorption of water from digests before excretion. In mammals, preparation for digestion begins with the cephalic phase in which saliva is produced in the mouth and digestive enzymes are produced in the stomach. Mechanical and chemical digestion begin in the mouth where food is chewed, and mixed with saliva to begin enzymatic processing of starches. The stomach continues to break food down mechanically and chemically through churning and mixing with both acids and enzymes.
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Four different purified hyaluronidases have been approved for use in the United States, three of animal origin and one recombinant. They are indicated as adjuvants in subcutaneous fluid administration for achieving hydration, for increasing the dispersion and absorption of other injected drugs, or for improving resorption of radiopaque agents, in subcutaneous urography. The three naturally-sourced hyaluronidases are orthologs of human HYAL5 (PH20) obtained from testicular preparations. They are sold under the trade names Vitrase (ovine, FDA-approved in May 2004), Amphadase (bovine, October 2004) and Hydase (bovine, October 2005).
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Oral tacrolimus is slowly absorbed in the gastrointestinal tract, with a total bioavailability of 20 to 25% (but with variations from 5 to 67%) and highest blood plasma concentrations (Cmax) reached after one to three hours. Taking the drug together with a meal, especially one rich in fat, slows down resorption and reduces bioavailability. In the blood, tacrolimus is mainly bound to erythrocytes; only 5% are found in the plasma, of which more than 98.8% are bound to plasma proteins. The substance is metabolized in the liver, mainly via CYP3A, and in the intestinal wall.
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The ideal pulpotomy treatment should leave the radicular pulp alive and healthy In this case, the tooth should be filled with noxious restorative materials within, thereby diminishing the chances of internal resorption, as well as formation of reparative dentin.Calcium hydroxide was the first agent used in pulpotomies that demonstrated any capacity to induce regeneration of dentin. However, the success rate is not that high. Recent advances in the field of bone and dentin formation have opened exciting new vistas for pulp therapy, which is a factor called bone morphogenetic protein (BMP).
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1062; New York, Saunders and Co. Parathyroid hormone regulates serum calcium through its effects on bone, kidney, and the intestine: In bone, PTH enhances the release of calcium from the large reservoir contained in the bones. Bone resorption is the normal destruction of bone by osteoclasts, which are indirectly stimulated by PTH. Stimulation is indirect since osteoclasts do not have a receptor for PTH; rather, PTH binds to osteoblasts, the cells responsible for creating bone. Binding stimulates osteoblasts to increase their expression of RANKL and inhibits their secretion of osteoprotegerin (OPG).
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Medication-related osteonecrosis of the jaw (MON, MRONJ) is progressive death of the jawbone in a person exposed to a medications known to increase the risk of disease, in the absence of a previous radiation treatment. It may lead to surgical complication in the form of impaired wound healing following oral and maxillofacial surgery, periodontal surgery, or endodontic therapy. Particular medications can result in MRONJ, a serious but uncommon side effect in certain individuals. Such medications are frequently used to treat diseases that cause bone resorption such as osteoporosis, or to treat cancer.
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Lingualized occlusion is defined as a form of denture occlusion that articulates the maxillary lingual cusps with the mandibular occlusal surfaces in centric, working, and non-working mandibular positions. The concept of lingualized occlusion was again influenced by Gysi, when he designed a crossbite posterior teeth model concept. He observed that more than half of edentulous patients at the University of Zurich had a posterior crossbite following normal physiological residual ridge resorption. In addition, a lingualised occlusion overcame the difficulties of setting up teeth in the prosthetic laboratory according to a bilateral balanced occlusion.
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As bone is resorbed, collagen and minerals are released into the local microenvironment creating both the space and minerals needed for osteoblasts to lay down new bone. As a decoy receptor for RANKL, OPG inhibits RANK-RANKL interactions thus suppressing osteoclastogenesis and bone resorption. OPG is also a decoy receptor for TRAIL, another regulator of osteoclastogenesis in osteoclast precursor cells and an autocrine signal for mature osteoclast cell death. TRAIL induces osteoclastogenesis by binding to specific TRAIL receptors on osteoclast precursor cell surfaces, inducing TRAF6 signalling, activating NF-κB signalling and upregulating NFATc1 expression.
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In the process of morphogenesis focuses PVL pass through three stages: 1) necrosis, 2) resorption, and 3) the formation gliosis scars or cysts. Cysts occur when large and confluent focuses of PVL, with mixed necrosis (kollikvacia in the center and coagulation rim at the periphery). Around the foci is generally defined area of other lesions of the brain white matter - the death of prooligodendrocytes, proliferation mikrogliocytes and astrocytes, swelling, bleeding, loss of capillaries, and others (the so-called "diffuse component PVL"). However, diffuse lesions without necrosis are not PVL.
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Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. This gene product is a type I membrane protein that is highly expressed in normal tissues, such as kidney, colon and pancreas, and has been found to be overexpressed in 10% of clear cell renal carcinomas. Two transcript variants encoding different isoforms have been identified for this gene.
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The increased bone density is due to lopsidedness between bones forming and bone resorption. This enzyme has a couple of essential functions in the body that, if removed, could lead to the symptoms observed with the disease. Thromboxane-A synthase is responsible for platelet aggregation and the regulation of bone mineral density. Thromboxane-A synthase regulates bone mineral density by influencing the two genes TNFSF₁₁ and TNFSF₁₁B, which encode for RANKL and osteoclastogenesis inhibitory factor in osteoblasts, so if the regulation did not occur it consequently leads to sclerosis.
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Vitamin A is fat-soluble and high levels have been reported to affect metabolism of the other fat-soluble vitamins D, E, and K. The toxic effects of vitamin A might be related to altered vitamin D metabolism, concurrent ingestion of substantial amounts of vitamin D, or binding of vitamin A to receptor heterodimers. Antagonistic and synergistic interactions between these two vitamins have been reported, as they relate to skeletal health. Stimulation of bone resorption by vitamin A has been reported to be independent of its effects on vitamin D.
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Neuropathic arthropathy (or neuropathic osteoarthropathy), also known as Charcot joint (often Charcot foot) after the first to describe it, Jean-Martin Charcot, refers to progressive degeneration of a weight bearing joint, a process marked by bony destruction, bone resorption, and eventual deformity due to loss of sensation. Onset is usually insidious. If this pathological process continues unchecked, it can result in joint deformity, ulceration and/or superinfection, loss of function, and in the worst-case scenario, amputation or death. Early identification of joint changes is the best way to limit morbidity.
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Blood calcium concentration are kept within a narrow range. If deficient, calcium will be mobilized from the bone to compensate imbalances. The ratio of calcium to phosphorus is essential to bone and teeth health; if there is excessive phosphorus within a diet, it can result in resorption and reduction of the alveolar bone as shown in Henrikson’s studies when dogs were fed a low calcium, high phosphorus diet. Vitamin D also plays a major role in calcium absorption and bone health because it helps to maintain calcium homeostasis and bone metabolism.
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There are a number of active biologic mediators that have been implicated in promoting apical resorption. Matrix metalloproteinases (MMPs), which are endogenous zinc-dependent catabolic enzymes, are primarily responsible for the degradation of much of the tissue matrices built on such architecturally important substances as collagen and proteoglycan core proteins. Their biologic activities have been extensively researched and reviewed, and their importance in the pathogenesis of apical periodontitis is obvious. Furthermore, concentrations of IgG antibodies have been found to be nearly five times higher in lesions of apical periodontitis than in uninflamed oral mucosa.
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Retention and Stability \- If prescribing a removable prosthesis and there is limited remaining firm teeth in the dentition an overdenture may aid in retention and stability compared to that of a conventional removable prosthesis. Preventative Dentistry \- The use of an overdenture delays the process of leaving the patient completely edentulous and assists in the preservation of bone. \- As a main priority for many dentists and patients, preventative dentistry is a reason for prescribing an overdenture as it retains the natural teeth for longer. Patient Anatomy \- Overdentures can be useful for patients with a severe ridge defect or bone resorption.
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Greenstein G, Cavallaro J. _The relationship between biologic concepts and fabrication of surgical guides for dental implant placement_. Compendium 2007;28(4):130-137 When implants are placed too palatally or lingually due to aberrant anatomical landmarks, bone resorption or surgical error, it is wise to place the implant more apically to increase the available running room in order to allow for a more convex emergence profile and avoid a buccal ridge-lap of the prosthetic crown in fixed partial denture cases. Similarly, when narrower than normal implant connections are used, deeper placement may enhance one's ability to generate an optimal emergence profile.
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In normal calcium regulation, a decrease in plasma calcium levels causes the parathyroid glands to secrete parathyroid hormone (PTH), which regulates the activation of Vitamin D3 in the kidney. These two compounds act to increase blood calcium levels by increasing absorption of dietary calcium from the intestine, increasing renal tubular reabsorption of calcium in the kidney, and increasing resorption of calcium from bones. It has been found that tissue is less responsive to parathyroid hormone prepartum, compared to postpartum. It is believed that hypocalcemia causing milk fever is due to a lower level of responsiveness of the cow's tissues to circulating parathyroid hormone.
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Zygoma implants (or zygomatic implants) are different from conventional dental implants in that they anchor in to the zygomatic bone (cheek bone) rather than the maxilla (upper jaw). They may be used when maxillary bone quality or quantity is inadequate for the placement of regular dental implants. Inadequate maxillary bone volume may be due to bone resorption as well as to pneumatization of the maxillary sinus or to a combination of both. The minimal bone height for a standard implant placement in the posterior region of the upper jaw should be about 10 mm to ensure acceptable implant survival.
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Outside of this context, atelectasis implies some blockage of a bronchiole or bronchus, which can be within the airway (foreign body, mucus plug), from the wall (tumor, usually squamous cell carcinoma) or compressing from the outside (tumor, lymph node, tubercle). Another cause is poor surfactant spreading during inspiration, causing the surface tension to be at its highest which tends to collapse smaller alveoli. Atelectasis may also occur during suction, as along with sputum, air is withdrawn from the lungs. There are several types of atelectasis according to their underlying mechanisms or the distribution of alveolar collapse; resorption, compression, microatelectasis and contraction atelectasis.
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This size appears to be the top length in fully grown individuals, as indicated by the advanced age of ZPAL MgD-III/3, which features areas of bone resorption and bone remodeling on the femur and tibia. The describing authors indicated some distinguishing traits. Gobihadros differs from all known other non-hadrosaurid hadrosauroids in possessing a double-layered tomial edge of the premaxilla and the presence of as much as three teeth per tooth position in the lower jaw. These are typical hadrosaurid traits and were concluded to have been acquired separately by the Hadrosauridae in a process of parallel evolution.
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Periodontal fremitus occurs in either of the alveolar bones when an individual sustains trauma from occlusion. It is a result of teeth exhibiting at least slight mobility rubbing against the adjacent walls of their sockets, the volume of which has been expanded ever so slightly by inflammatory responses, bone resorption or both. As a test to determine the severity of periodontal disease, a patient is told to close his or her mouth into maximum intercuspation and is asked to grind his or her teeth ever so slightly. Fingers placed in the labial vestibule against the alveolar bone can detect fremitus.
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The alveolar support of the affected tooth will be lowered due to continuous replacement resorption of the root. This process will stop with the appearance of root fractures and shed crown, and changes in dentition, especially the anterior teeth, can be observed in this stage. Symptoms such as infraocclusion and asymmetry in the smile arc may be developed. However, for ankylosis in posterior teeth happening in non-growing subjects, it may be completely asymptomatic because the slow change in height of the affected teeth may not be noticeable to both the patient and the doctor, compared to that happened in anterior teeth.
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It is recommended over extraction because it limits bone resorption and therefore maintains a sufficient growth of alveolar bone to enable tooth implantation . Decoronation can be carried out on both deciduous and permanent teeth. However, if the patient is too young and not close to puberty, decoronation should be postponed . In order to maximize the benefits of decoronation, regular monitoring and intervention are needed For non-growing patients, decoronation is generally not recommended because the growth of alveolar bone may be inadequate for a future tooth implant, and therefore is said to not give ideal treatment outcomes.
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Microdontia may be present in one or more of the other teeth. This means that the teeth appear smaller than normal, may be observed in both the primary and permanent dentition. This condition can be genetically-linked and in severe cases, may present themselves in the form of ectodermal dysplasia, cleft lip or palate or Down Syndrome. A delay in tooth development may also serve as an indication, whereby the absence of an adult successor slows down the normal resorption of the roots of the baby teeth, which is the progressive loss of parts of the tooth.
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It is also thought that blood concentration of the bone formation stimulant, Insulin-like Growth Factor-I (IGF-I), is increased from high protein consumption and parathyroid hormone (PTH), a bone resorption stimulant, is decreased. Although protein has shown to be beneficial for increasing bone mass, or bone mineral density, there is no significant association between protein intake and fracture incidence. In other words, a low BMD can be predictive of osteoporosis and increased fracture risk, but a higher BMD does not necessarily mean better bone health. High BMD is also correlated with other health issues.
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Research areas include: regulation of bone remodeling; mechanisms of bone formation, bone resorption and mineralization; and effects of hormones, growth factors and cytokines on bone cells. The programs emphasize the application of fundamental knowledge of bone cell biology to the development of drug and gene therapies for bone diseases, especially osteoporosis. This program area supports several large epidemiologic cohorts for the characterization of the natural history of osteoporosis and for the identification of genetic and environmental risk factors that contribute to bone disease. Muscle Biology and Diseases—support PDCTC research projects in skeletal muscle biology and diseases.
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Many long-term problems with hip replacements are the result of osteolysis. This is the loss of bone caused by the body's reaction to polyethylene wear debris, fine bits of plastic that come off the cup liner over time. An inflammatory process causes bone resorption that may lead to subsequent loosening of the hip implants and even fractures in the bone around the implants. In an attempt to eliminate the generation of wear particles, ceramic bearing surfaces are being used in the hope that they will have less wear and less osteolysis with better long-term results.
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Renal osteodystrophy has been classically described to be the result of hyperparathyroidism secondary to hyperphosphatemia combined with hypocalcemia, both of which are due to decreased excretion of phosphate by the damaged kidney. Low activated vitamin D3 levels are a result of the damaged kidneys' inability to convert vitamin D3 into its active form, calcitriol, and result in further hypocalcaemia. High levels of fibroblast growth factor 23 seem now to be the most important cause of decreased calcitriol levels in CKD patients. In CKD, the excessive production of parathyroid hormone increases the bone resorption rate and leads to histologic bone signs of secondary hyperparathyroidism.
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M-CSF released by osteoblasts (as a result of endocrine stimulation by parathyroid hormone) exerts paracrine effects on osteoclasts. M-CSF binds to receptors on osteoclasts inducing differentiation, and ultimately leading to increased plasma calcium levels—through the resorption (breakdown) of bone. Additionally, high levels of CSF-1 expression are observed in the endometrial epithelium of the pregnant uterus as well as high levels of its receptor CSF1R in the placental trophoblast. Studies have shown that activation of trophoblastic CSF1R by local high levels of CSF-1 is essential for normal embryonic implantation and placental development.
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Sodium is the most common cation in the extracellular space. The excess chloride within sweat ducts prevents sodium resorption by epithelial sodium channels and the combination of sodium and chloride creates the salt, which is lost in high amounts in the sweat of individuals with CF. This lost salt forms the basis for the sweat test. Most of the damage in CF is due to blockage of the narrow passages of affected organs with thickened secretions. These blockages lead to remodeling and infection in the lung, damage by accumulated digestive enzymes in the pancreas, blockage of the intestines by thick feces, etc.
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The indication of this pulpotomy procedure is when pulp exposure occurs during caries removal in a primary tooth with a normal pulp or reversible pulpitis or after a traumatic pulp exposure. Then, the coronal tissue is amputated, and the remaining radicular tissue is judged to be vital without suppuration, pus, necrosis, or excessive bleeding which cannot be controlled by a moist cotton pellet (with saline) after several minutes, and there are no radiographic signs of infection or pathologic resorption. Pulpotomy therapy can be classified according to the following treatment objectives: devitalization (mummification, cauterization), preservation (minimal devitalization, noninductive), or regeneration (inductive, reparative).
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These changes are due to increased capillary permeability and an influx of inflammatory cells into the gingival tissues. When gingival disease remain established and the aetiology is not removed there is further recruitment of cells such as macrophages which assist with the phagocytic digestion of bacteria and lymphocytes which begin to initiate an immune response./ Pro-inflammatory cytokines are produced inside the gingival tissues and further escalate inflammation which impacts the progression of chronic systemic inflammation and disease. The result is collagen breakdown, infiltrate accumulation as well as collagen breakdown in the periodontal ligament and alveolar bone resorption.
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The structure and activity relationship of toremifene is similar to that of tamoxifen, but it has a substantial improvement from the older drug in regards to DNA alkylation. The presence of the added chlorine atom reduces the stability of cations formed from activated allylic metabolites and thus decreases alkylation potential, and indeed toremifene does not display DNA adduct formation in rodent hepatocytes. Toremifene protects against bone loss in ovariectomized rat models and affects bone resorption markers clinically in a similar fashion to tamoxifen. Toremifene undergoes phase I metabolism by microsomal cytochrome P450 enzymes, like tamoxifen, but primarily by the CYP3A4 isoform.
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There are two principles that Donald Enlow developed which are important part of the study of the craniofacial development. Enlow's V Principle is related to the bones of the craniofacial area which have a V shape configuration. We see bone resorption happening on the outer side of the "V" of the bone and bone deposition happens on the inner side of the "V". Therefore, the movement of bone happens towards the open-end of the V. Enlow's Counterpart Principle states that growth of one bone in the craniofacial area relates to the other bones in the same region.
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The quartz crystals exist in a fine-grained matrix, usually of micro-crystalline or felsitic structure. In specimens, the quartz appears as small rounded, clear, greyish, vitreous blebs, which are crystals, double hexagonal pyramids, with their edges and corners rounded by resorption or corrosion. Under the microscope they are often seen to contain rounded enclosures of the ground-mass or fluid cavities, which are frequently negative crystals with regular outlines resembling those of perfect quartz crystals. Many of the latter contain liquid carbonic acid and a bubble of gas that may exhibit vibratile motion under high magnifying powers.
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Nosiheptide consists of 5 thiazole rings, a central tetrasubstituted pyridine moiety, and a bicyclic macrocycle, which includes a modified amino acid (from tryptophan) external to the initial peptide translated from the gene encoding it. It is used as a feed additive in the growth of poultry and hogs to promote growth and general health, although it has not been applied in human medicines due to low water solubility and poor resorption from the gastrointestinal tract. Nosiheptide and other thiopeptide's mechanism of action stems from the tight binding on the 50S ribosomal subunit and inhibiting the activities of elongation factors, preventing protein synthesis.
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The most common form of gingivitis, and the most common form of periodontal disease overall, is in response to bacterial biofilms (also called plaque) that is attached to tooth surfaces, termed plaque-induced gingivitis. Most forms of gingivitis are plaque-induced.Dental Hygiene - E-Book: Theory and Practice, by Michele Leonardi Darby, Margaret Walsh, page 318 While some cases of gingivitis never progress to periodontitis, periodontitis is always preceded by gingivitis. Gingivitis is reversible with good oral hygiene; however, without treatment, gingivitis can progress to periodontitis, in which the inflammation of the gums results in tissue destruction and bone resorption around the teeth.
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Teeth are constantly subject to both horizontal and vertical occlusal forces. With the center of rotation of the tooth acting as a fulcrum, the surface of bone adjacent to the pressured side of the tooth will undergo resorption and disappear, while the surface of bone adjacent to the tensioned side of the tooth will undergo apposition and increase in volume.Trauma from Occlusion Handout, Dr. Michael Deasy, Department of Periodontics, NJDS 2007. page 4 In both primary and secondary occlusal trauma, tooth mobility might develop over time, with it occurring earlier and being more prevalent in secondary occlusal trauma.
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A common clinical sign associated with the histopathology will be varying levels of suppuration and purulence. Following the spread of local inflammation, chemical mediators such as IL-8, IL-6 and IL-1 are released from necrotic tissues leading to further inflammation and odema, which advances to total necrosis of the pulp. Further stages of destruction of pulp necrosis often leads to periapical pathosis, causing bone resorption (visible on radiographs) following bacterial invasion. The apical periodontal ligament (PDL) space widens and becomes continuous with apical radiolucency; the lamina dura of the apical area will also be lost.
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The roots of the teeth were striated at their bases, and some were roughly quadrangular, as in many other ophthalmosaurids, but not square-shaped as in Platypterygius. Some of the roots of SNHM1284-R had resorption pits, indicating it was still growing teeth. The size of the only known complete tooth crown was relatively small compared to other ophthalmosaurids, slender, and sharply pointed, similar to the hind teeth of Baptanodon. The basal two thirds of the crown had subtle, longitudinal ridges, and was covered in a coarse texture, finer than in Aegirosaurus and some Platypterygius secimens.
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Because the abutment is narrower in diameter than the implant fixture, a certain amount of the implant platform is exposed when an implant is platform switched, and this exposed area of the platform can allow for the tissues of the biologic width -- junctional epithelium and soft connective tissue—to begin forming here, requiring less bone to be resorbed to make room for attachment on the lateral surface of the implant fixture.Greenstein G, et al. _Treatment planning implant dentistry with a 2 mm twist drill_. Compendium 2010;31(2):2-10 Platform switching has been shown to have the potential to reduce the vertical bone resorption by as much as 70%.
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The bone marrow cavity is important for the proper development of the immune system, and houses important stem cells for maintenance of the immune system. Within this space, as well as outside of it, cytokines produced by immune cells also have important effects on regulating bone homeostasis. Some important cytokines that are produced by the immune system, including RANKL, M-CSF, TNFa, ILs, and IFNs, affect the differentiation and activity of osteoclasts and bone resorption. Such inflammatory osteoclastogenesis and osteoclast activation can be seen in ex vivo primary cultures of cells from the inflamed synovial fluid of patients with disease flare of the autoimmune disease rheumatoid arthritis.
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In particular, the 1997 observation by Skulan and DePaolo that calcium minerals are isotopically lighter than the solutions from which the minerals precipitate is the basis of analogous applications in medicine and in paleooceanography. In animals with skeletons mineralized with calcium, the calcium isotopic composition of soft tissues reflects the relative rate of formation and dissolution of skeletal mineral. In humans, changes in the calcium isotopic composition of urine have been shown to be related to changes in bone mineral balance. When the rate of bone formation exceeds the rate of bone resorption, the 44Ca/40Ca ratio in soft tissue rises and vice versa.
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Chemical structure of bisphosphonates Bisphosphonates are an important class of drugs originally introduced about half a century ago. They are used for the treatment of osteoporosis and other bone disorders that cause bone fragility and diseases where bone resorption is excessive. Osteoporosis is common in post-menopausal women and patients in corticosteroid treatment where biphosphonates have been proven a valuable treatment and also used successfully against Paget's disease, myeloma, bone metastases and hypercalcemia. Bisphosphonates reduce breakdown of bones by inhibiting osteoclasts, they have a long history of use and today there are a few different types of bisphosphonate drugs on the market around the world.
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However, majority of cases are shown to relapse into inherited class III malocclusion during the pubertal growth stage and when the appliance is removed after treatment. Another approach is to carry out orthognathic surgery, such as a bilateral sagittal split osteotomy (BSSO) which is indicated by horizontal mandibular excess. This involves surgically cutting through the mandible and moving the fragment forward or backwards for desired function and is supplemented with pre and post surgical orthodontics to ensure correct tooth relationship. Although the most common surgery of the mandible, it comes with several complications including: bleeding from inferior alveolar artery, unfavorable splits, condylar resorption, avascular necrosis and worsening of temporomandibular joint.
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Therefore, it is strongly believed that their incidence may be due to different causes. For ankylosis in permanent teeth, with the first molar being the most common affected teeth, it is hard to find a precise cause because of the complicated nature which is believed to be linked to several different factors and the difficulty in diagnosis as many cases are asymptomatic. For other cases, there are several theories explaining the cause. Dental trauma may be a major cause for the disease since it can lead to luxation, reported in 30 to 44% of all dental trauma cases, and hence replacement resorption, which is the situation in ankylosis of teeth.
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M.B. Katan et al., Efficacy and Safety of Plant Stanols and Sterols in the Management of Blood Cholesterol Levels, Mayo Clinic Proceedings 78, 965-978 (2003) In recent years the Becel/Flora brand has added cooking oil, pot yogurt and yogurt drinks to the non-margarine products, all of which are designed to help lower blood cholesterol level. This is achieved by a highly increased resorption of beta-sitosterol and other phytosterols which accumulate especially in the intima of blood vessels and may cause arteriosclerotic plaques. In consequence, consumption of Becel products does not lower the risk for coronary diseases such as arteriosclerosis and therefore does not inherit any medical benefits.
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Follow-on Phase 3 randomized trials showed the drug was superior to other agents used at that time, including injectable calcitonin and intravenous etidronate. Concurrent studies also suggested clinical activity in patients with severe hypercalcemia due to parathyroid carcinoma as well as patients with bone diseases, including Paget's disease, multiple myeloma, and bone metastases. In 2003, the drug was approved as Ganite® (gallium nitrate solution) for the treatment of hypercalcemia resistant to hydration, and the drug was marketed by Fujisawa Inc. Work at the Hospital for Special Surgery in New York and elsewhere suggested that gallium reduced bone resorption and might also stimulate bone formation.
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There are several different ways for aquatic tetrapod to counteract their positive buoyancy caused by their lungs: pachyostosis, osteosclerosis, pachyosteosclerosis, and calcified cartilage of bone. The ultimate goal of these processes are to increase density for different parts of the body to offset the buoyancy, in order to live in an aquatic/semi-aquatic environment. Bone histology of Pistosaurus longaevus studied by Paleontologist Krahl showed that the medullary region of humeri was filled, and it contained calcified cartilage incorporated into endoseal bone. According to Krahl, the small region of medullary of humeri is results from a suppressed perimedullary resorption activity, which is associated with osteosclerosis.
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Chlortalidone (or other thiazide medication) is a key component of treatment of nephrogenic diabetes insipidus. Nephrogenic diabetes insipidus occurs when the kidney is unable to produce concentrated urine because it has an inadequate response to vasopressin-dependent removal of free water from the renal tubular filtrate. By blocking sodium ion resorption in the distal convoluted tubule, chlortalidone induces an increase in excretion of sodium ion in urine (natriuresis). Giving chlortalidone while simultaneously restricting dietary sodium intake causes mild hypovolemia (low intravascular volume), which induces isotonic reabsorption of solute from the proximal renal tubule, reducing solute delivery in the renal collecting tubule and renal medullary collecting duct.
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Sintered materials increase the crystallinity of calcium phosphate in certain artificial bones, which leads to poor resorption by osteoclasts and compromised biodegradability. One study avoided this by creating inkjet-printed, custom-made artificial bones that utilized α-tricalcium phosphate (TCP), a material that converts to hydroxyapatite and solidifies the implant without the use of sintering. In addition, α-TCP is biocompatible and helps form new bone, which is better for patients in the long term. Artificial bone designs must be biocompatible, have osteoconductivity, and last for long periods of time inside a patient in order to be a viable solution compared to autologous and allogeneic bone implants.
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Bismuth oxide is occasionally used in dental materials to make them more opaque to X-rays than the surrounding tooth structure. In particular, bismuth (III) oxide has been used in hydraulic silicate cements (HSC), originally in "MTA" (a trade name, standing for the chemically- meaningless "mineral trioxide aggregate") from 10 to 20% by mass with a mixture of mainly di- and tri-calcium silicate powders. Such HSC is used for dental treatments such as: apicoectomy, apexification, pulp capping, pulpotomy, pulp regeneration, internal repair of iatrogenic perforations, repair of resorption perforations, root canal sealing and obturation. MTA sets into a hard filling material when mixed with water.
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The secretion of IL-6 by bone marrow stromal cells (BMSC) and the secretion of the adhesion molecules VCAM-1, ICAM-1 and LFA, is induced in the presence of TNF-α and the adhesion of MM cells to BMSC. In vitro proliferation of MM cell lines and inhibition of Fas-mediated apoptosis is promoted by IL-6. Thalidomide and its analogs directly decrease the up-regulation of IL-6 and indirectly through TNF-α, thereby reducing the secretion of adhesion molecules leading to fewer MM cells adhering to BMSC. Osteoclasts become highly active during MM, leading to bone resorption and secretion of various MM survival factors.
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Communicating hydrocephalus, also known as nonobstructive hydrocephalus, is caused by impaired CSF reabsorption in the absence of any obstruction of CSF flow between the ventricles and subarachnoid space. This may be due to functional impairment of the arachnoidal granulations (also called arachnoid granulations or Pacchioni's granulations), which are located along the superior sagittal sinus, and is the site of CSF reabsorption back into the venous system. Various neurologic conditions may result in communicating hydrocephalus, including subarachnoid/intraventricular hemorrhage, meningitis, and congenital absence of arachnoid villi. Scarring and fibrosis of the subarachnoid space following infectious, inflammatory, or hemorrhagic events can also prevent resorption of CSF, causing diffuse ventricular dilatation.
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Estrogen contributes to bone health in several ways; low estrogen levels increase bone resorption via osteoclasts and osteocytes, cells that help with bone remodeling, making bones more likely to deteriorate and increase risk of fracture. The decline in estrogen levels can ultimately lead to more serious illnesses, such as scoliosis or type I osteoporosis, a disease that thins and weakens bones, resulting in low bone density and fractures. Estrogen deficiency plays an important role in osteoporosis development for both genders, and it is more pronounced for women and at younger (menopausal) ages by five to ten years compared with men. Females are also at higher risk for osteopenia and osteoporosis.
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In women, estrogens are the main component in proper bone formation. Through the stimulation of growth factors such as transforming growth factor beta (TGF-B), bone morphogenetic protein 6 (6-BMP-6), and IGF-1 and inhibition of receptor activator of nuclear factor kappa-B ligand (RANKL), estrogen tends to suppress bone resorption and activate bone formation and remodeling units. Because FHA causes hypoestrogenism, women with FHA may lack age-appropriate bone density and have an increased risk of skeletal fragility, stress fractures, osteopenia, and osteoporosis. The profile of low serum IGF-1, low serum insulin, and high serum cortisol also contribute to low BMD.
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Retinoic acid suppresses osteoblast activity and stimulates osteoclast formation in vitro, resulting in increased bone resorption and decreased bone formation. It is likely to exert this effect by binding to specific nuclear receptors (members of the retinoic acid receptor or retinoid X receptor nuclear transcription family) which are found in every cell (including osteoblasts and osteoclasts). This change in bone turnover is likely to be the reason for numerous effects seen in hypervitaminosis A, such as hypercalcemia and numerous bone changes such as bone loss that potentially leads to osteoporosis, spontaneous bone fractures, altered skeletal development in children, skeletal pain, radiographic changes, and bone lesions.
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The Death of Rats refused to be reabsorbed into Death himself upon the latter's resumption of his duties; therefore Death kept him around for company. The Death of Fleas also escaped resorption, but has not been seen since Reaper Man. The Death of Rats resembles a rodentine skeleton walking on its hind legs, wearing a black robe, and carrying a tiny scythe, his form having taken shape from the latent form of Death himself in Reaper Man, as he came into existence in the vicinity of Bill Door. The Death of Rats more easily finds ways around the rules than Death does, and has assisted Susan in Soul Music, Hogfather, and Thief of Time.
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Deoxypyridinoline, also called D-Pyrilinks, Pyrilinks-D, or deoxyPYD, is one of two pyridinium cross-links that provide structural stiffness to type I collagen found in bones. It is excreted unmetabolized in urine and is a specific marker of bone resorption and osteoclastic activity. It is measured in urine tests and is used along with other bone markers such as alkaline phosphatase, osteocalcin, and N-terminal telopeptide to diagnose bone diseases such as postmenopausal osteoporosis, bone metastasis, and Paget's disease, furthermore, it has been useful in monitoring treatments that contain bone- active agents such as estrogens and bisphosphonates. Certain studies have attempted to generate a standardization of Deoxypyridinoline via an individual molar absorptivity value at acid and neutrality pH.
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However, osteoporosis is essentially the result of a lack of new bone formation in combination with bone resorption in reactive hyperemia, related to various causes and contributing factors, and bisphosphonates do not address these factors at all. In 2011, a proposal incorporating both the reduced bone turnover and the infectious elements of previous theories has been put forward. It cites the impaired functionality of affected macrophages as the dominant factor in the development of ONJ. In a systematic review of cases of bisphosphonate-associated ONJ up to 2006, it was concluded that the mandible is more commonly affected than the maxilla (2:1 ratio), and 60% of cases are preceded by a dental surgical procedure.
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Imbalances in calcium and phosphorus levels can result in various skeletal complications. Excess phosphorus can produce lesions in bones whereas excessive calcium can lead to hypocalcaemia and result in excess bone deposition, interfering with normal bone development. In extreme circumstances of insufficient calcium intake, bone resorption can occur due to the body withdrawing calcium deposits from the skeletal frame as a last resort to fulfill dietary needs. Omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been shown to be highly effective in the prevention of cartilage catabolism in in vitro models, suggesting that its supplementation in food could aid in decreasing the symptoms of osteoarthritis in German shepherds.
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Life restoration showing hypothetical nasal ornamentation Like all sauropod dinosaurs, Brachiosaurus was a quadruped with a small skull, a long neck, a large trunk with a high-ellipsoid cross section, a long, muscular tail and slender, columnar limbs. Large air sacs connected to the lung system were present in the neck and trunk, invading the vertebrae and ribs by bone resorption, greatly reducing the overall density of the body. The neck is not preserved in the holotype specimen, but was very long even by sauropod standards in the closely related Giraffatitan, consisting of thirteen elongated cervical (neck) vertebrae. The neck was held in a slight S-curve, with the lower and upper sections bent and a straight middle section.
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When osteocytes were experimentally destroyed, the bones showed a significant increase in bone resorption, decreased bone formation, trabecular bone loss, and loss of response to unloading. Osteocytes are thought to be mechanosensor cells that control the activity of osteoblasts and osteoclasts within a basic multicellular unit (BMU), a temporary anatomic structure where bone remodeling occurs. Osteocytes generate an inhibitory signal that is passed through their cell processes to osteoblasts for recruitment to enable bone formation. Osteocyte specific proteins such as sclerostin have been shown to function in mineral metabolism, as well as other molecules such as PHEX, DMP-1, MEPE, and FGF-23, which are highly expressed by osteocytes and regulate phosphate and biomineralization.
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Loss of muscle power makes it extremely difficult, if not impossible, for astronauts to climb through emergency egress hatches or create unconventional exit spaces in the case of a crash upon landing. Additionally, bone resorption and inadequate hydration in space can lead to the formation of kidney stones, and subsequent sudden incapacitation due to pain. If this were to occur during critical phases of flight, a capsule crash leading to worker injury and/or death could result. Short-term and long-term health effects have been seen in the cardiovascular system from exposure to the micro-g environment that would limit those exposed after they return to Earth or a regular gravity environment.
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Pericoronitis (green arrow) in lower right wisdom tooth Impacted wisdom teeth without a communication to the mouth, that have no pathology associated with the tooth, and have not caused tooth resorption on the blocking tooth, rarely have symptoms. The chances of developing pathology on an impacted wisdom tooth that is not communicating with the mouth is approximately 12%. However, when impacted wisdom teeth communicate with the mouth, food and bacteria penetrate to the space around the tooth and cause symptoms such as localized pain, swelling and bleeding of the tissue overlying the tooth. The tissue overlying the tooth is called the operculum, and the disorder is called pericoronitis which means inflammation around the crown of the tooth.
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Adrenal Steroids such as glucocorticoids and mineralocorticoids are commonly used as treatments in diseases such as Cogenital adrenal hyperplasia. CAH commonly causes overproduction of androgens, glucocorticoid treatment is used to reduce Adrenocorticotropic hormone (ACTH) and reduce the production of androgens allowing for symptoms of CAH to be managed though treatment is required to be continued regularly for life or symptoms may return. Glucocorticoids are known to cause suppression of osteoblastic activity causing reduction in bone formation during development and cause an increased amount of bone resorption causing the breaking down of bone tissue. This commonly leads to diseases such as Osteopenia and Osteoporosis in developing humans due to reduced bone mineral density and bone volume density.
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Cortisol reduces bone formation, favoring long-term development of osteoporosis (progressive bone disease). The mechanism behind this is two-fold: cortisol stimulates the production of RANKL by osteoblasts which stimulates, thought bind to RANK receptors, the activity of osteoclasts - cells responsible for calcium resorption from bone - and also inhibits the production of osteoprotegerin (OPG) which acts as a decoy receptor and captures some RANKL before it can activate the osteoclasts through RANK. In other words, when RANKL binds to OPG, no response occurs as opposed to the binding to RANK which leads to the activation of osteoclasts. It transports potassium out of cells in exchange for an equal number of sodium ions (see above).
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Instead, non-pathological bone resorption, or unknown bone diseases, are suggested as causes. A newer study compared incidence rates of skull lesions and periosteal reaction in Triceratops and Centrosaurus and showed that these were consistent with Triceratops using its horns in combat and the frill being adapted as a protective structure, while lower pathology rates in Centrosaurus may indicate visual rather than physical use of cranial ornamentation, or a form of combat focused on the body rather than the head. The frequency of injury was found to be 14% in Triceratops. The researchers also concluded that the damage found on the specimens in the study was often too localized to be caused by bone disease.
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The RANK/RANKL/OPG axis is a critical pathway in maintaining the symbiosis between bone resorption by osteoclasts and bone formation by osteoblasts. RANKL is released by osteoblast lineage cells and binds to receptor RANK on the surface of osteoclast progenitor cells RANK- RANKL binding activates the nuclear factor kappa B (NF-κB) pathway resulting in the upregulation of the transcription factor nuclear factor of activated T-cells cytoplasmic 1 (NFATc1). NFATc1 is a master regulator for the expression of essential cytokines during the differentiation of osteoclast precursor cells into mature osteoclasts, known as osteoclastogenesis. Mature osteoclasts then bind to bone through tight junctions and release digestive enzymes to resorb the old bone.
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Though expressivity is varied depending on the mutation responsible for decrease in enzyme function, severe cutaneous sensitivity is present in most cases of this Porphyria. An estimated 30–40% of cases are due to the C73R mutation, which decreases stability of the enzyme and results in <1% of its activity. Exposure to long-wave ultraviolet light causes the affected skin to thicken and produce vesicles that are prone to rupture and infection; these secondary infections, along with bone resorption, can lead to disfigurement of the sun-exposed face and extremities. Enzyme dysfunction prevents the normal production of heme and hemolytic anemia is another common symptom, though a lack of hemolysis in this disease is possible.
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Apical abscess associated with roots of a lower molar. Apical periodontitis is acute or chronic inflammation around the apex of a tooth caused by an immune response to bacteria within an infected pulp. It does not occur because of pulp necrosis, meaning that a tooth that tests as if it's alive (vital) may cause apical periodontitis, and a pulp which has become non-vital due to a sterile, non-infectious processes (such as trauma) may not cause any apical periodontitis. Bacterial cytotoxins reach the region around the roots of the tooth via the apical foramina and lateral canals, causing vasodilation, sensitization of nerves, osteolysis (bone resorption) and potentially abscess or cyst formation.
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Micrograph showing Paget's disease of the bone with the characteristic jigsaw puzzle-like/mosaic pattern, H&E; stain The pathogenesis of Paget's disease is described in four stages: # Osteoclastic activity # Mixed osteoclastic – osteoblastic activity # Osteoblastic activity # Malignant degeneration Initially, there is a marked increase in the rate of bone resorption in localized areas, caused by large and numerous osteoclasts. These localized areas of pathological destruction of bone tissue (osteolysis) are seen radiologically as an advancing lytic wedge in long bones or the skull. When this occurs in the skull, it is called osteoporosis circumscripta. The osteolysis is followed by a compensatory increase in bone formation induced by the bone forming cells, called osteoblasts, that are recruited to the area.
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Male N. vitripennis wasps produce pheromones from papillae inside a rectal vesicle, and release pheromones through the anus. Female wasps show no similar organ for pheromone release. Prior research has pointed to the rectal papillae (inside the rectal vesicle) for the purpose of water and electrolyte resorption, since the adult male wasps rarely feed; however, localization techniques, pheromone biosynthesis data and observations of wasp behaviour (tapping abdomen on the ground, leaving traces of pheromone) all point to these organs being used in sexual communication. Cephalic pheromones are also present in N. vitripennis, coming from the mouth of the males during courtship, which females contact with their antennae while signaling their receptivity to mating.
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Here blood sugar regulation is unable to function because the beta cells of the pancreatic islets are destroyed and cannot produce the necessary insulin. The blood sugar rises in a condition known as hyperglycemia. The plasma ionized calcium homeostat can be disrupted by the constant, unchanging, over-production of parathyroid hormone by a parathyroid adenoma resulting in the typically features of hyperparathyroidism, namely high plasma ionized Ca2+ levels and the resorption of bone, which can lead to spontaneous fractures. The abnormally high plasma ionized calcium concentrations cause conformational changes in many cell-surface proteins (especially ion channels and hormone or neurotransmitter receptors) giving rise to lethargy, muscle weakness, anorexia, constipation and labile emotions.
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The C-terminal telopeptide (CTX), also known as carboxy-terminal collagen crosslinks, is the C-terminal telopeptide of fibrillar collagens such as collagen type I and type II. It is used as a biomarker in the serum to measure the rate of bone turnover. It can be useful in assisting clinicians to determine a patient's nonsurgical treatment response as well as evaluate a patient's risk of developing complications during healing following surgical intervention.Marx, RE, et al. _Oral Bisphosphonate-Induced Osteonecrosis: Risk Factors, Prediction of Risk Using Serum CTX Testing, Prevention, and Treatment_ , J Oral Maxillofac Surg 2007;65:2397-2410 The test used to detect the CTX marker is called the Serum CrossLaps, and it is more specific to bone resorption than any other test currently available.
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Plant functional types (PFTs) is a system used by climatologists to classify plants according to their physical, phylogenetic and phenological characteristics as part of an overall effort to develop a vegetation model for use in land use studies and climate models. PFTs provide a finer level of modeling than biomes, which represent gross areas such as desert, savannah, deciduous forest. In creating a PFT model, areas as small as 1 km2 are modeled by defining the predominant plant type for that area, interpreted from satellite data or other means. For each plant functional type, a number of key parameters are defined, such as fecundity, competitiveness, resorption (rate at which plant decays and returns nutrients to the soil after death), etc.
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Over 30 specimens of A. vorax are known from the type locality near Dresden. The ontogenetic changes have been described in detail most recently by Witzmann & Schoch (2006). Among the changes that occur are a proportional shortening of the femur and the trunk relative to the skull and a distinct remodeling of the hyobranchial apparatus, with resorption of the larval form's ceratobranchials and the formation of a complex apparatus of hypobranchials that the authors suggested was for supporting the tongue. Based on the changes to the skeleton and the distribution of size classes within the locality, Witzmann & Schoch (2006) suggested that A. vorax had a biphasic life history, with an aquatic larval to juvenile form and a terrestrial adult form.
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The mitochondria are needed in order to supply the energy for the active transport of sodium ions out of the cells to create a concentration gradient which allows more sodium ions to enter the cell from the luminal side. Water passively follows the sodium out of the cell along its concentration gradient. Cuboidal epithelial cells lining the proximal tubule have extensive lateral interdigitations between neighboring cells, which lend an appearance of having no discrete cell margins when viewed with a light microscope. Agonal resorption of the proximal tubular contents after interruption of circulation in the capillaries surrounding the tubule often leads to disturbance of the cellular morphology of the proximal tubule cells, including the ejection of cell nuclei into the tubule lumen.
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When there is a case of hypodontia of the permanent premolar teeth, the primary molar teeth would often remain in the mouth beyond the time they are meant to be lost. Therefore, with a presence of healthy primary teeth in the absence of a permanent successor, retaining the primary teeth can be a feasible management of hypodontia. The primary molars present also functions as a space maintainer, prevent alveolar bone resorption and delays future prosthodontic space replacement by acting as a semi permanent solution going into adulthood Previous studies also shown a good prognosis of retained primary molars going into adulthood. However, leaving the primary teeth in place may run the risk of tooth infraocclusion where the occlusal surface is below that of adjacent teeth.
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Socket preservation procedure prevents immediate bone resorption after extraction thus keeping the contour and integrity of the socket with a successful and natural-looking appearance for tooth restorative procedures. All dental prosthesis requires good jaw bone support for it to be successful in the long run. Without socket preservation, residual bones could lose volume resulting in loss of facial vertical and horizontal dimension and changes in facial soft tissues aesthetics. A 2015 Cochrane study found that there was evidence that socket preservation does indeed improve the height and width, compared to extraction without socket preservation but that there is insufficient data to conclude that it decreases implant failures, improves aesthetics, or that one grafting material is any better than another.
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With the center of rotation of the tooth acting as a fulcrum, the surface of bone adjacent to the pressured side of the tooth will undergo resorption and disappear, while the surface of bone adjacent to the tensioned side of the tooth will undergo apposition and increase in volume.Trauma from Occlusion Handout, Dr. Michael Deasy, Department of Periodontics, NJDS 2007. page 4 When the amount of root remaining in the bone is so short that the entire surface of bone adjacent to the root surface is constantly under compression or tension (with no middle section acting as a stabilizer for the fulcrum), the prognosis for the tooth is deemed highly unfavorable. This is usually the outcome associated with untreated secondary occlusal trauma.
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Osteitis fibrosa cystica ( ), is a skeletal disorder resulting in a loss of bone mass, a weakening of the bones as their calcified supporting structures are replaced with fibrous tissue (peritrabecular fibrosis), and the formation of cyst-like brown tumors in and around the bone. Osteitis fibrosis cystica, abbreviated OFC, also known as osteitis fibrosa, osteodystrophia fibrosa, and von Recklinghausen's disease of bone (not to be confused with von Recklinghausen's disease, neurofibromatosis type I), is caused by hyperparathyroidism, which is a surplus of parathyroid hormone from over- active parathyroid glands. This surplus stimulates the activity of osteoclasts, cells that break down bone, in a process known as osteoclastic bone resorption. The hyperparathyroidism can be triggered by a parathyroid adenoma, hereditary factors, parathyroid carcinoma, or renal osteodystrophy.
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Osteoclastic bone resorption releases minerals, including calcium, from the bone into the bloodstream, causing both elevated blood calcium levels, and the structural changes which weaken the bone. The symptoms of the disease are the consequences of both the general softening of the bones and the excess calcium in the blood, and include bone fractures, kidney stones, nausea, moth-eaten appearance in the bones, appetite loss, and weight loss. First described in the nineteenth century, OFC is currently detected through a combination of blood testing, X-rays, and tissue sampling. Before 1950, around half of those diagnosed with hyperparathyroidism in the United States saw it progress to OFC, but with early identification techniques and improved treatment methods, instances of OFC in developed countries are increasingly rare.
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The affinities of estrone for the human ERs and its estrogenic activity have been reported to be approximately 3 to 4% of those of estradiol. In addition, unlike estradiol and estriol, estrone is not accumulated in target tissues. Because estrone can be transformed into estradiol, most of its activity in vivo is actually due to conversion into estradiol. In accordance, doses of oral and transdermal estradiol that achieve similar levels of estradiol have been found, in spite of markedly elevated levels of estrone with oral estradiol but not with transdermal estradiol, to possess equivalent and non-significantly different potency in terms of clinical measures including suppression of LH and FSH levels, inhibition of bone resorption, and relief of menopausal symptoms such as hot flashes.
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In contrast, 16α-LE2 stimulates uterine weight, whereas 8β-VE2 has no effect, indicating that the ERα and not the ERβ is involved in the effects of estrogen on the uterus. Research has determined through experimental rodent studies with estradiol, 16α-LE2, and 8β-VE2 that the positive, protective effects of estrogens on bone formation resorption and bone mineral density are mediated via the ERα, whereas the ERβ does not appear to be involved. On the other hand, while both ERα and ERβ are expressed in skeletal muscle, it was found that ERβ is the predominant ER subtype that is responsible for estrogen stimulation of skeletal muscle growth and regeneration. Moreover, similarly to testosterone, 8β-VE2 has anabolic effects in skeletal muscle and significantly increases muscle mass as well as produces muscle hypertrophy in rats.
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Tyrosine-protein kinase CSK is involved in the following developmental, metabolic, and signal transduction cascades: Adherens junction organization, blood coagulation, brain development, cell differentiation, cell migration, cellular response to peptide hormone stimulus, central nervous system development, epidermal growth factor receptor signaling pathway, innate immune response, epithelium morphogenesis, regulation of bone resorption, negative regulation of cell proliferation, negative regulation of ERK1 and ERK2 cascade, negative regulation of Golgi to plasma membrane protein transport, negative regulation of interleukin-6 production, negative regulation of kinase activity, negative regulation of low-density lipoprotein particle clearance, negative regulation of phagocytosis, dendrocyte differentiation, peptidyl-tyrosine autophosphorylation, platelet activation, positive regulation of MAP kinase activity, regulation of cell proliferation, regulation of cytokine production, regulation of Fc receptor mediated stimulatory signaling pathway, T cell costimulation, T cell receptor signaling pathway.
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In spite of markedly elevated levels of estrone with oral estradiol but not with transdermal estradiol, clinical studies have shown that dosages of oral and transdermal estradiol achieving similar levels of estradiol possess equivalent and non-significantly different potency in terms of measures including suppression of luteinizing hormone and follicle- stimulating hormone levels, inhibition of bone resorption, and relief of menopausal symptoms such as hot flashes. In addition, estradiol levels were found to correlate with these effects, while estrone levels did not. These findings confirm that estrone has very low estrogenic activity, and also indicate that estrone does not diminish the estrogenic activity of estradiol. This contradicts some cell-free in-vitro research suggesting that high concentrations of estrone might be able to partially antagonize the actions of estradiol.
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Observed adverse effects in rats included fetal resorption in rates (at doses _>_ 50 mg/kg per day), delays in sexual development in female rats (at doses _>_ 30 mg/kg per day), and decreased birth weight (at doses _>_ 3.6 mg/kg per day). A 2014 systematic review, funded by atrazine manufacturer Syngenta, assessed its relation to reproductive health problems. The authors concluded that the quality of most studies was poor and without good quality data, the results were difficult to assess, though it was noted that no single category of negative pregnancy outcome was found consistently across studies. The authors concluded that a causal link between atrazine and adverse pregnancy outcomes was not warranted due to the poor quality of the data and the lack of robust findings across studies.
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Generally speaking partial dentures tend to be held in place by the presence of the remaining natural teeth and complete dentures tend to rely on muscular co-ordination and limited suction to stay in place. The maxilla very commonly has more favorable denture bearing anatomy as the ridge tends to be well formed and there is a larger area on the palate for suction to retain the denture. Conversely, the mandible tends to make lower dentures much less retentive due to the displacing presence of the tongue and the higher rate of resorption, frequently leading to significantly resorbed lower ridges. Disto- lingual regions tend to offer retention even in highly resorbed mandibles, and extension of the flange into these regions tends to produce a more retentive lower denture.
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Variations on the theme in biology are enormous, ranging from trophic eggs to resorption of partly developed embryos in hard times or when they are too numerous for the mother to bring to term, but among the most profoundly advantageous features of viviparity are various forms of physiological support and protection of the embryo, such as thermoregulation and osmoregulation. Since the developing offspring remains within the mother's body, she becomes, in essence, a walking incubator, protecting the developing young from excessive heat, cold, drought, or flood. This offers powerful options for dealing with excessive changes in climate or when migration events expose populations to unfavourable temperatures or humidities. In squamate reptiles in particular, there is a correlation between high altitudes or latitudes, colder climates and the frequency of viviparity.
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With clinical use, estriol is said to be weakly estrogenic in certain tissues, such as the liver and endometrium, but produces pronounced and full estrogenic responses in the vaginal epithelium. The medication has been found to reduce hot flashes, improve vaginal atrophy, reverse the postmenopausal decline in skin thickness and collagen content, suppress gonadotropin secretion, and produce proliferation of breast epithelium. Conversely, estriol does not consistently affect bone resorption or fracture risk, does not seem to increase breast density, and, at oral doses of 2 to 4 mg/day, does not affect liver proteins, lipid metabolism, or hemostatic parameters. Additionally, vaginal estriol does not appear to produce endometrial proliferation or increase the risk of endometrial hyperplasia, and some studies have found this to be the case for oral estriol as well.
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When physicians later carried out gynaecological examinations, the cadaveric particles were absorbed by the patient, in particular if they came into contact with the freshly exposed uterus, or with genital tract lesions caused by the birth process. Semmelweis was convinced that every case of childbed fever was caused by resorption of cadaveric particles. With this etiology, Semmelweis identified childbed fever as purely an iatrogenic disease--that is, one caused by doctors. (Friedrich Wilhelm Scanzoni von Lichtenfels took personal offense at this, and never forgave Semmelweis for it—Scanzoni remained one of the most ardent critics of Semmelweis.) A few childbed fever case stories, described below, did not fit well into Semmelweis's theory and led him to expand it, also to comprise other types of decaying organic matter, for instance secretions from an infected knee or from a cancer tumor.
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Xenograft bone substitute has its origin from a species other than human, such as bovine bone (or recently porcine bone) which can be freeze dried or demineralized and deproteinized. Xenografts are usually only distributed as a calcified matrix. Madrepore and or millepore type of corals are harvested and treated to become 'coral derived granules' (CDG) and other types of coralline xenografts. Coral based xenografts are mainly calcium carbonate (and an important proportion of fluorides, useful in the context of grafting to promote bone development) while natural human bone is made of hydroxyapatite along with calcium phosphate and carbonate: the coral material is thus either transformed industrially into hydroxyapatite through a hydrothermal process, yielding a non-resorbable xenograft, or simply the process is omitted and the coralline material remains in its calcium carbonate state for better resorption of the graft by the natural bone.
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Solanesol possesses antimicrobial, anti-tumor, anti-inflammatory, and anti-ulcer activities, and it serves as an important pharmaceutical intermediate for the synthesis of coenzyme Q10, vitamin K2, and N-solanesyl-N,N′-bis(3,4-dimethoxybenzyl) ethylenediamine (SDB). The physiological functions of coenzyme Q10 include anti-oxidation, anti-aging, immune-function enhancement, cardiovascular enhancement, brain-function enhancement, and the regulation of blood lipids; it may be used for treating migraines, neurodegenerative diseases, hypertension, and cardiovascular diseases, and as a dietary supplement for patients with type 2 diabetes. Vitamin K2 promotes bone growth, inhibits bone resorption, stimulates bone mineralization, has preventive and therapeutic effects on osteoporosis, diminishes blood clotting, and reduces the progression of arteriosclerosis. The anti-cancer agent synergizer SDB allows P-glycoprotein-mediated multidrug resistance in cancer cells to be overcome, and has synergistic effects with certain anti-tumor drugs.
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Accordingly, this leads the upper parts of the mandible (alveolar process) to retract posteriorly, following the posterior movement of the upper tooth row, while the lower part of the symphysis remained protruded to create more space, thereby creating the inverted-T shaped mental relief during early ages and the prominent chin later. The alveolar region (upper or superior part of the symphysis) is sculpted by bone resorption, but the chin (lower or inferior part) is depository in its nature. These coordinated bone growth and modeling processes mold the vertical symphysis present at birth into the prominent shape of the chin. Recent research on the development of the chin suggests that the evolution of this unique characteristic was formed not by mechanical forces such as chewing but by evolutionary adaptations involving reduction in size and change in shape of the face.
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Of these animal models, the ovariectomised rat model remains the most popular choice as it has been validated to represent the most important clinical features of estrogen deficiency-induced (or postmenopausal) bone loss in the adult human, particularly during the early stages of osteoporosis. These include: increased rate of bone turnover with resorption exceeding formation; an initial rapid phase of bone loss followed by a much slower phase; greater loss of cancellous bone than cortical bone; reduced intestinal calcium absorption; some protection against bone loss by obesity; and similar skeletal response to therapy with estrogen, tamoxifen, bisphosphonates, parathyroid hormone, calcitonin and exercise. It also offers certain advantages compared the other animal models like rabbits and sheep. These include the ability to use peripheral micro-computed tomography (pQmicro-CT) in in vivo micro-CT to perform in vivo analyses, cost-effectiveness, and ease of handling and housing.
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With oral administration of estradiol, the ratio of estradiol levels to estrone levels is about 5 times higher on average than under normal physiological circumstances in premenopausal women and with parenteral (non-oral) routes of estradiol. Oral administration of menopausal replacement dosages of estradiol results in low, follicular phase levels of estradiol, whereas estrone levels resemble the high levels seen during the first trimester of pregnancy. In spite of markedly elevated levels of estrone with oral estradiol but not with transdermal estradiol, clinical studies have shown that doses of oral and transdermal estradiol achieving similar levels of estradiol possess equivalent and non-significantly different potency in terms of measures including suppression of luteinizing hormone and follicle- stimulating hormone levels, inhibition of bone resorption, and relief of menopausal symptoms such as hot flashes. In addition, estradiol levels were found to correlate with these effects, while estrone levels did not.
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The vitamin D receptor belongs to the nuclear receptor superfamily of steroid/thyroid hormone receptors, and VDRs are expressed by cells in most organs, including the brain, heart, skin, gonads, prostate, and breast. VDR activation in the intestine, bone, kidney, and parathyroid gland cells leads to the maintenance of calcium and phosphorus levels in the blood (with the assistance of parathyroid hormone and calcitonin) and to the maintenance of bone content. One of the most important roles of vitamin D is to maintain skeletal calcium balance by promoting calcium absorption in the intestines, promoting bone resorption by increasing osteoclast number, maintaining calcium and phosphate levels for bone formation, and allowing proper functioning of parathyroid hormone to maintain serum calcium levels. Vitamin D deficiency can result in lower bone mineral density and an increased risk of reduced bone density (osteoporosis) or bone fracture because a lack of vitamin D alters mineral metabolism in the body.
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The surgical and liposculpture contouring of the human body presents possible medical complications such as: the psychological — unmet body image expectations of aesthetic improvement; the physical — uneven contour, local and general; the physiologic — toxic reactions to the anaesthesic and the tumescent drugs; and the nervous — paresthesia, localized areas of perduring numbness in the corrected portion(s) of the gluteal region. The medical complications possible to a surgical buttocks augmentation procedure, the submuscular emplacement of a gluteal implant, include infection, surgical-wound dehiscence that exposes the implant, revision surgery, rupture of the implant, seroma (a pocket of clear serous fluid), capsular contracture, asymmetry of the corrected area, shifting of the implant, surgical over-correction, injury to the sciatic nerve, and paresthesia (tingling skin). The medical complications possible to a liposculpture buttocks augmentation include the bodily resorption of some of the injected adipose fat, asymmetric contour of the corrected body area, an irregular contour to the body, seroma, abscess (pus enclosed by inflamed tissue), cellulitis (subcutaneous connective-tissue inflammation), and paresthesia.
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In a standing position, the main outflow from the head is through the vertebral venous system because the internal jugular veins, located primarily between the carotid artery and the sternocleidomastoid muscle are partially or completely occluded due to the pressure from these structures, and in a supine position, the main outflow is through the internal jugular veins as they have fallen laterally due to the weight of the contained blood, are no longer compressed and have greatly expanded in diameter, but the smaller vertebral system has lost the gravitational force for blood outflow. In microgravity, there is no gravity to pull the internal jugular veins out from the zone of compression (Wiener classification Zone I), and there is also no gravitational force to pull blood through the vertebral venous system. In microgravity, the cranial venous system has been put into minimal outflow and maximal obstruction. This then causes a cascade of cranial venous hypertension, which decreases CSF resorption from the arachnoid granulations, leading to intracranial hypertension and papilledema.
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