Physical activity,social support and socio-economic status amongst persons living with HIV and AIDS: a review

Physical activity can be used for the effective and comprehensive management of HIV and AIDS. Social support and socio-economic status (SES) are two factors that shape physical activity behaviours. Individuals of low SES carry a disproportionate burden of the HIV and AIDS epidemic. In addition, limited resources constitute socio-ecological barriers predisposing such individuals to physical inactivity. The purpose of this narrative review is to examine the available literature on physical activity, social support and SES and to generate recommendations for designing and implementing physical activity interventions targeting people living with HIV and AIDS (PLWHA) of low SES. The review used literature from Google, Google Scholar and PubMed on physical activity of PLWHA, social support for physical activity, and SES and physical activity. Qualitative and quantitative studies in English were included from 1970 to 2016. The results show that social support plays a major role in promoting physical activity and counteracting the barriers to PA in PLWHA of low SES. The results on the role of social support and the influence of SES are integrated to help design appropriate physical activity interventions for PLWHA of low SES. Well-designed interventions should utilise social support and be contextualised for PLWHA of low SES, whose living conditions present multiple barriers to physical activity.     

Improved intravoxel incoherent motion analysis of diffusion weighted imaging by data driven Bayesian modeling

In addition to the diffusion coefficient, fitting the intravoxel incoherent motion model to multiple b‐value diffusion‐weighted MR data gives pseudo‐diffusion measures associated with rapid signal attenuation at low b‐values that are of use in the assessment of a number of pathologies. When summary measures are required, such as the average parameter for a region of interest, least‐squares based methods give adequate estimation accuracy. However, using least‐squares methods for pixel‐wise fitting typically gives noisy estimates, especially for the pseudo‐diffusion parameters, which limits the applicability of the approach for assessing spatial features and heterogeneity. In this article, a Bayesian approach using a shrinkage prior model is proposed and is shown to substantially reduce estimation uncertainty so that spatial features in the parameters maps are more clearly apparent. The Bayesian approach has no user‐defined parameters, so measures of parameter variation (heterogeneity) over regions of interest are determined by the data alone, whereas it is shown that for the least‐squares estimates, measures of variation are essentially determined by user‐defined constraints on the parameters. Use of a Bayesian shrinkage prior approach is, therefore, recommended for intravoxel incoherent motion modeling. Magn Reson Med 71:411–420, 2014. © 2013 Wiley Periodicals, Inc.     

What Can I Do With a Doctoral Degree in Gerontology? Expanding Your Options

An endless number of career trajectories are possible for gerontologists. With a growing aging population, our skills and areas of expertise are of high value to numerous industries. The purpose of this study is to describe the professional development and career trajectories of alumni of U.S. doctoral gerontology programs obtained through the Gerontology Education Longitudinal Study (GELS). Specifically, the authors examine how professional identification, doctoral program career preparation, and perception of job prospects affect alumni decisions to pursue “traditional” (i.e., academic) versus “nontraditional” (i.e., non-academic) careers. Results from the GELS revealed a fairly even split in the alumni sample of careers in traditional and nontraditional settings. The decision to pursue a traditional versus nontraditional career was not significantly associated with personal identification, doctoral program career preparation, or perception of employment options. These results suggest that the skill set obtained in doctoral gerontology programs is useful and is in demand in a variety of careers; therefore, doctoral programs may want to consider tailoring training to meet students’ future career goals in both academic and non-academic settings.     

Signal transduction by the platelet Fc receptor

We have evaluated the mechanism by which crosslinking human platelet Fc receptor (FcR) for IgG triggers platelet aggregation and the platelet release reaction. Platelet FcR was crosslinked by incubating purified human platelets with anti-FcRII monoclonal antibody and F(ab')2 anti- mouse Ig. The resultant [Ca2+]i increase, monitored by Fura-2 and measured in the absence of extracellular Ca2+, reached a peak of 750 +/- 50 nmol/L. The effects of cyclooxygenase inhibitors, aspirin and indomethacin, and a phospholipase A2 inhibitor, dibromoacetophenone, were examined. Regardless of the inhibitor, at least 25% of the [Ca2+]i increase remained. Thrombin (0.2 U/mL) stimulated an immediate [Ca2+]i increase that reached 1.95 +/- 0.8 mumol/L. The [Ca2+]i increase generated by thrombin was only slightly reduced by these inhibitors. Crosslinking the FcRII of platelets resulted in a fivefold increase in the production of [3H]inositol phosphates, (IP) which, in the absence of extracellular Ca2+ was insensitive to aspirin. The activation of a [Ca2+]i increase along with the measured increases in IP indicate that FcRII crosslinking leads to the activation of phospholipase C (PLC). In contrast to thrombin, platelet activation via FcRII depends to a large extent on arachidonic acid metabolites. However, neither cyclooxygenase nor phospholipase A2 inhibitors completely blocked FcRII-stimulated [Ca2+]i increase. These observations led us to propose that crosslinking of platelet FcRII initially activates PLC.