Publications

In cultured human keratinocytes or murine epidermis, peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) (NR1C2) activators (1) stimulate keratinocyte differentiation; (2) decrease keratinocyte proliferation; (3) accelerate permeability barrier repair; (4) increase epidermal lipid synthesis; and (5) reduce cutaneous inflammation. Since these results suggest that PPARbeta/delta could play an important role in cutaneous homeostasis, we assessed here the skin phenotype of mice deficient in PPARbeta/delta. Gross cutaneous abnormalities were not evident, and both stratum corneum (SC) skin hydration and surface pH were normal. However, the epidermis was thickened and proliferating cell nuclear antigen (PCNA) staining was increased, indicating increased cell proliferation. No change in apoptosis was observed but the expression of differentiation markers, such as filaggrin, involucrin, and loricrin, was slightly increased in PPARbeta/delta(-/-) mice. Although basal permeability barrier function was normal, PPARbeta/delta knockout (KO) mice show a significant delay in barrier recovery rates following acute barrier disruption by either acetone treatment or tape-stripping. Delayed barrier recovery correlated with decreased production and secretion of lamellar bodies (LBs), and with reduced numbers of extracellular lamellar membranes in the SC. Finally, PPARbeta/delta KO mice displayed increased inflammation in response to 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment. Together, these results further demonstrate that PPARbeta/delta in the epidermis: (1) is required for permeability barrier homeostasis; (2) regulates keratinocyte proliferation; and (3) modulates cutaneous inflammation.

Childhood socioeconomic status (SES) acts over a lifetime to influence adult health outcomes. Whether the impact of childhood SES differs by age or race/ethnicity is unclear. The authors studied 20,566 community-living US adults aged > or =50 years. Parental education was the main predictor. Outcomes evaluated (1998-2002) included self-reported health and functional limitation. The influence of childhood SES on later-life health was also examined in groups stratified by age and race/ethnicity, with adjustment for demographic factors and current SES. Participants' mean age was 67 years; 57% were women. By race/ethnicity, 76% were White, 14% were Black, and 8% were Latino. The relation between low parental education and fair/poor self-rated health declined with advancing age (age 50-64 years: adjusted odds ratio (AOR) = 1.42, 95% confidence interval (CI): 1.24, 1.63; age > or =80 years: AOR = 1.14, 95% CI: 0.96, 1.36). The relation between low parental education and fair/poor self-rated health differed across racial/ethnic groups and was significant in White (AOR = 1.33, 95% CI: 1.21, 1.47) and Black (AOR = 1.37, 95% CI: 1.14, 1.64) participants but not Latinos. These findings suggest that childhood SES affects health status through midlife but the effects may abate in late life; its effects also may be weaker in Latinos than in Whites or Blacks.

OBJECTIVE

To characterize the overlap between injection drug use and sex work by women in Tijuana and Cd. Juarez, situated on the Mexico-U.S. border.

METHODS

FSWs aged > or =18 years who were not knowingly HIV-positive and reported having unprotected sex with > or =1 client in the prior 2 months underwent interviews and testing for HIV, syphilis, gonorrhea and Chlamydia. Logistic regression identified factors associated with injecting drugs within the last month.

RESULTS

Of 924 FSWs, 18.0% had ever injected drugs. Among FSW-IDUs (N=114), prevalence of HIV, syphilis titers > or =1:8, gonorrhea and Chlamydia was significantly higher at 12.3%, 22.7%, 15.2% and 21.2% compared to 4.8%, 13.1%, 5.2% and 11.9% among other FSWs (N=810). FSW-IDUs also had more clients in the past 6 months (median: 300 versus 240, p=0.02). Factors independently associated with injecting drugs in the past month included living in Tijuana, being younger, being married/common-law, longer duration in the sex trade, speaking English, earning less for sex without condoms, often using drugs before sex, and knowing other FSWs who injected drugs.

CONCLUSIONS

FSW-IDUs had higher STI levels, engaged in riskier behaviors and were more vulnerable to having unsafe sex with clients compared to other FSWs, indicating that this subgroup is an important bridge population requiring focused prevention.