Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Disuse has been shown to cause a rapid and dramatic loss of skeletal mass and strength in the load-bearing bones of young and mature animals and humans. However, little is known about the skeletal effects of disuse in aged mammals. The present study was designed to determine whether the skeletal effects of disuse are maintained with extreme age. Fischer 344/Brown Norway male rats (6 and 32 mo old) were hindlimb suspended (HS) or housed individually for 2 wk. Trabecular volume and microarchitecture in the proximal tibia were significantly decreased by HS only in young rats. HS significantly reduced cortical bone mineral density and increased cortical porosity only in old rats by inducing new pore formation. Cortical pore diameter was also increased in old rats, regardless of loading condition. Ex vivo osteogenic and adipogenic cultures established from each group demonstrated that age and HS decreased osteoblastogenesis. Age, but not HS, decreased sensitivity to endogenous bone morphogenetic protein stimulation, as measured by treatment with exogenous Noggin. Adipocyte development increased with age, whereas HS suppressed sensitivity to peroxisome proliferator-activated receptor-gamma-induced differentiation. Serum insulin-like growth factor I levels were reduced with HS in young rats and with age in control and HS rats. These results suggest that the site of bone loss due to disuse is altered with age and that the loss of osteogenic potential with disuse in the old rats may be due to the combined effects of decreased insulin-like growth factor I levels and sensitivity, as well as diminished bone morphogenetic protein production.
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PMID:Aging alters the skeletal response to disuse in the rat. 1706 63

Proximal symphalangism (SYM1) is an autosomal-dominant developmental disorder of joint fusion. This disorder is best known from famous historical descriptions of two large kindred: Cushing's description in 1916 of the "straight-fingered" Brown family of Virginia and Drinkwater's description in 1917 of the British Talbot family of noble blood, descended from the English war hero John Talbot, the first Earl of Shrewsbury (1388-1453). Recent genetic studies link this phenotype to expression of abnormal genes at future joint sites: too little expression of NOG, a growth antagonist, or overexpression of GDF5, a growth agonist, results in cartilage overgrowth and bony fusion. This review unites in depth the first historical accounts of SYM1 with a clinical description and reviews the current understanding of the molecular mechanism underlying what is likely the oldest dominant trait ever studied.
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PMID:Cushing proximal symphalangism and the NOG and GDF5 genes. 1799 31