Clinical characteristics influence in vitro action of 1,25-dihydroxyvitamin D(3) in human marrow stromal cells.

Vitamin D is important for bone health, with low vitamin D levels being associated with skeletal fragility and fractures. Among its other biological activities, 1,25-dihydroxyvitamin D (1,25(OH)(2) D), stimulates the in vitro differentiation of human marrow stromal cells (hMSCs) to osteoblasts, which can be monitored by increases in alkaline phosphatase enzyme activity or osteocalcin gene expression. In this study, we tested the hypotheses that age and clinical attributes of subjects influence in vitro responsiveness of hMSCs to 1,25(OH)(2) D(3) .

Effects of age on parathyroid hormone signaling in human marrow stromal cells.

Human bone marrow stromal cells (hMSCs) have the potential to differentiate into osteoblasts; there are age-related decreases in their proliferation and differentiation to osteoblasts. Parathyroid hormone (PTH), when applied intermittently in vivo, has osteoanabolic effects in a variety of systems. In this study, we compared PTH signaling and osteoanabolic effects in hMSCs from young and old subjects.

Cultural perception of harassment in two groups of medical students: American and Israeli.

The aims of this study were to determine whether harassment occurs in the authors' school, the Sackler Faculty of Medicine at Tel Aviv University, and to address the possible influence of cultural background on the perception of harassment. The unique makeup of the school was utilized, with two separate programs for American and Israeli students trained at the same sites and by the same faculty. A two-part questionnaire was developed that included students' reports on the occurrence of harassment, at what stage of their studies, by whom and its nature as well as demographic data.