Glomerular Aging and Focal Global Glomerulosclerosis: A Podometric Perspective.

Kidney aging is associated with an increasing proportion of globally scarred glomeruli, decreasing renal function, and exponentially increasing ESRD prevalence. In model systems, podocyte depletion causes glomerulosclerosis, suggesting age-associated glomerulosclerosis could be caused by a similar mechanism. We measured podocyte number, size, density, and glomerular volume in 89 normal kidney samples from living and deceased kidney donors and normal poles of nephrectomies. Podocyte nuclear density decreased with age due to a combination of decreased podocyte number per glomerulus and increased glomerular volume. Compensatory podocyte cell hypertrophy prevented a change in the proportion of tuft volume occupied by podocytes. Young kidneys had high podocyte reserve (podocyte density >300 per 10(6) µm(3)), but by 70-80 years of age, average podocyte nuclear density decreased to, <100 per 10(6) µm(3), with corresponding podocyte hypertrophy. In older age podocyte detachment rate (urine podocin mRNA-to-creatinine ratio) was higher than at younger ages and podocytes were stressed (increased urine podocin-to-nephrin mRNA ratio). Moreover, in older kidneys, proteinaceous material accumulated in the Bowman space of glomeruli with low podocyte density. In a subset of these glomeruli, mass podocyte detachment events occurred in association with podocytes becoming binucleate (mitotic podocyte catastrophe) and subsequent wrinkling of glomerular capillaries, tuft collapse, and periglomerular fibrosis. In kidneys of young patients with underlying glomerular diseases similar pathologic events were identified in association with focal global glomerulosclerosis. Podocyte density reduction with age may therefore directly lead to focal global glomerulosclerosis, and all progressive glomerular diseases can be considered superimposed accelerators of this underlying process.

Information Behavior and HIV Testing Intentions Among Young Men at Risk for HIV/AIDS.

Health research shows that knowing about health risks may not translate into behavior change. However, such research typically operationalizes health information acquisition with knowledge tests. Information scientists who investigate socially embedded information behaviors could help improve understanding of potential associations between information behavior-as opposed to knowledge-and health behavior formation, thus providing new opportunities to investigate the effects of health information. We examine the associations between information behavior and HIV testing intentions among young men who have sex with men (YMSM), a group with high rates of unrecognized HIV infection. We used the theory of planned behavior (TPB) to predict intentions to seek HIV testing in an online sample of 163 YMSM. Multiple regression and recursive path analysis were used to test two models: (a) the basic TPB model and (b) an adapted model that added the direct effects of three information behaviors (information exposure, use of information to make HIV-testing decisions, prior experience obtaining an HIV test) plus self-rated HIV knowledge. As hypothesized, our adapted model improved predictions, explaining more than twice as much variance as the original TPB model. The results suggest that information behaviors may be more important predictors of health behavior intentions than previously acknowledged.

Self-efficacy among young men who have sex with men: an exploratory analysis of HIV/AIDS risk behaviors across partner types.

HIV infection continues to rise among young men who have sex with men (YMSM). We explored whether unprotected receptive anal intercourse (URAI) occasions and partners, respectively, were associated with YMSM's (N = 194; ages 18-24) self-efficacy for safe sex with regular and casual partners. We created four self-efficacy typologies: high self-efficacy with both partner types [HRHC; N = 73(41.7 %)], high self-efficacy with regular partners but low with casual partners [HRLC; N = 24(13.7 %)], low self-efficacy with regular partners but high with casual partners [LRHC; N = 21(12.0 %)], and low with both partner types [LRLC; N = 57(32.6 %)]. YMSM in the LRHC category reported fewer URAI occasions, whereas those in the HRLC group reported more URAI partner and occasions, respectively. YMSM having serodiscordant partners were more likely to report more URAI partners, and be represented in the LRLC category. These findings underscore the importance of addressing differential self-efficacy across partner types, and highlight an urgent need to enhance YMSM's self-efficacy with casual partners.

How "community" matters for how people interact with information: mixed methods study of young men who have sex with other men.

BACKGROUND: We lack a systematic portrait of the relationship between community involvement and how people interact with information. Young men who have sex with men (YMSM) are a population for which these relationships are especially salient: their gay community involvement varies and their information technology use is high. YMSM under age 24 are also one of the US populations with the highest risk of HIV/AIDS. OBJECTIVE: To develop, test, and refine a model of gay community involvement (GCI) factors in human-information interaction (HII) as applied to HIV/AIDS information among YMSM, specifically examining the role of Internet use in GCI and HII. METHODS: Mixed methods included: 1) online questionnaire with 194 YMSM; and 2) qualitative interviews with 19 YMSM with high GCI levels. Recruitment utilized social media, dating websites, health clinics, bars/clubs, and public postings. The survey included questions regarding HIV/AIDS-related information acquisition and use patterns, gay community involvement, risk behaviors, and technology use. For survey data, we tested multiple linear regression models using a series of community- and information-related variables as dependent variables. Independent variables included community- and information-related variables and demographic covariates. We then conducted a recursive path analysis in order to estimate a final model, which we refined through a grounded theory analysis of qualitative interview data. RESULTS: Four community-related variables significantly predicted how people interact with information (HII variables): 1) gay community involvement (GCI), 2) social costs of information seeking, 3) network expertise accessibility, and 4) community relevance. GCI was associated with significantly lower perceived social costs of HIV/AIDS information seeking (R(2)=0.07). GCI and social costs significantly predicted network expertise accessibility (R(2)=0.14). GCI predicted 14% of the variance in community relevance and 9% of the variance in information seeking frequency. Incidental HIV/AIDS information acquisition (IIA) was also significantly predicted by GCI (R(2)=0.16). 28% of the variance in HIV/AIDS information use was explained by community relevance, network expertise access, and both IIA and information seeking. The final path model showed good fit: the RSMEA was 0.054 (90% CI: .000-.101); the Chi-square was non-significant (χ(2)(11)=17.105; P=.105); and the CFI was 0.967. Qualitative findings suggest that the model may be enhanced by including information sharing: organizing events, disseminating messages, encouraging safety, and referring and recommending. Information sharing emerged under conditions of pro-social community value enactment and may have consequences for further HII. YMSM with greater GCI generally used the Internet more, although they chatted online less. CONCLUSIONS: HIV/AIDS-related HII and associated technology uses are community-embedded processes. The model provides theoretical mediators that may serve as a focus for intervention: 1) valuing HIV/AIDS information, through believing it is relevant to one's group, and 2) supportive and knowledgeable network members with whom to talk about HIV/AIDS. Pro-social community value endorsement and information sharing may also be important theoretical mediators. Our model could open possibilities for considering how informatics interventions can also be designed as community-level interventions and vice versa.

Using online peer-mentoring to empower young adults with end-stage renal disease: a feasibility study.

Patients with end-stage renal disease must receive a kidney transplant or live on dialysis. Either treatment option introduces radical changes to their lifestyles and may result in significant psychosocial disruptions. Among these patients, young adults (YAs)-between age 18 and 30-are confronted with unique challenges because their life course is yet to be defined and their adulthood identity has not fully emerged. Partnering with the National Kidney Foundation of Michigan, we experimented with a web-based "peer-mentoring" intervention to create a user-driven, self-sustained online community. The objective was to help YAs develop "new normal" lives, restore social identities, and regain confidence in school and work. To foster a comforting online atmosphere for this vulnerable population, it is critical to use tailored technology designs catering to their needs and concerns. In this paper, we describe a prototype that we developed-ktalk.org, and report our findings from pilot-testing it with 38 YAs.