Comparison of areal and estimated volumetric bone mineral density values between older men and women.

We compared areal bone mineral density (BMD) of the total body (TBMD), antero-posterior lumbar spine at L3 (APS), lateral spine at L3 (LS) and femoral neck (FN). In order to understand better the effect of gender-related size differences on BMD, we also compared the estimated volumetric BMD at L3 (VLS) and the femoral neck (VFN). Subjects were asymptomatic women (n = 22) and men (n = 44) with an age range of 58-79 years. BMD at each site was measured by dual-energy X-ray absorptiometry using a Hologic 2000 in array mode. Results of the statistical analyses (ANOVA) showed the men to have significantly greater BMD at all areal sites [APS, LS (p < 0.05); FN (p < 0.01); TBMD (p < 0.001)]. The two estimated volumetric comparisons, however, showed no gender differences. Results demonstrate how measures from areal BMD measures can be misleading when comparing groups of different size. In older men and women planar measures may overestimate gender differences in BMD.

In vitro effects of T-2 toxin on the mitogen responsiveness and antibody-producing ability of human lymphocytes.

The effects of T-2 toxin on the in vitro mitogen responses and the antibody-producing ability of human peripheral blood lymphocytes were evaluated. T-2 toxin inhibited the mitogen response to concanavalin A (ConA) at a lower concentration (1.6 ng/ml) as compared to phytohemagglutinin (2.4 ng/ml) and pokeweed mitogen (2.4 ng/ml). Maximum inhibition was observed when the toxin was present during the first 8 h; however, the cultures were not refractory to inhibition until 48 h after culture initiation. The antibody-producing ability was inhibited by T-2 toxin concentrations of greater than or equal to 3.2 ng/ml. T-2 toxin did not induce or interfere with the generation of suppressor cells by ConA. The results of this study indicate that various lymphocyte subpopulations have different susceptibilities to T-2 toxin. The activation process associated with lymphocyte proliferation appears to be one of the most sensitive time periods.