Bone
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Profound bone loss at weight bearing sites is a primary effect of long-duration spaceflight. Moreover, a significant increase in estimated fracture risk remains even 1 year after returning to Earth; hence, it is important to define how quickly bone integrity can recover following prolonged disuse. This study characterized the loss and recovery dynamics of bone following a period of rodent hindlimb unloading in three anatomic sites. ⋯ However, the inaccuracy of strength indices vs. directly measured mechanical properties highlights the continued importance of ground based animal models and mechanical testing. Our results demonstrate that the PTM in the rat better matches loss and recovery dynamics observed in astronauts' proximal femur than does the rat FN, at least in terms of densitometric variables. More complete utility of the rat PTM as a model in this case, however, depends upon meaningful characterization of changes in mechanical properties as well.
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Meta Analysis
Osteoporosis risk and bone mineral density levels in patients with Parkinson's disease: a meta-analysis.
Parkinson's disease (PD) and osteoporosis are common diseases which affect a substantial portion of the elderly population. Accumulating evidence supports that PD patients have a high risk for osteoporosis in recent years. The purpose of the present study is to perform a meta-analysis on the risk of osteoporosis and bone mineral density (BMD) levels in PD patients. ⋯ This meta-analysis suggested that PD patients are at higher risk for osteoporosis and have lower BMD levels than healthy controls overall.
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The cytoskeleton determines cell shape and is involved in cell motility. It also plays a role in differentiation and in modulating specialized cellular functions. LIM kinase 1 (LIMK1) participates in cytoskeletal remodeling by phosphorylating and inactivating the actin-severing protein, cofilin. ⋯ LIMK1(-/-) osteoclasts also resorbed dentine slices to a greater extent in vitro and were more active in a pit assay. These data support the hypothesis that LIMK1 is required for normal osteoblast differentiation. In addition, its absence leads to increased cytoskeletal remodeling and bone resorption in osteoclasts.