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This study examined the association between sexual relationship power, intimate partner violence, and condom use among African American and Hispanic urban girls. In this sample of 56 sexually active girls, 50% did not use condoms consistently and therefore were at higher risk for acquiring HIV or sexually transmitted diseases (STDs). Teens who experienced more intimate partner violence had a significantly higher likelihood of inconsistent condom use and therefore a greater risk for HIV/STDs. Girls' sense of sexual control in their relationships was not directly associated with inconsistent condom use but was inversely related to verbal and emotional abuse. Interventions aimed at reducing HIV/STD risk for adolescent girls need to address patterns of dominance and control in adolescent relationships as well as multiple forms of partner violence. This suggests the need for multilevel intervention approaches that promote girls' agency and multiple ways to keep girls safe from perpetrators of partner abuse. Keywords: adolescents; prevention; condom use; partner abuse; relationship power: intimate partner violence

Naturally SIV-infected sooty mangabeys (SMs) remain asymptomatic despite high virus replication. Elucidating the mechanisms underlying AIDS resistance of SIV-infected SMs may provide crucial information to better understand AIDS pathogenesis. In this study, we assessed the determinants of set-point viremia in naturally SIV-infected SMs, i.e., immune control of SIV replication versus target cell limitation. We depleted [CD4.sup.+] T cells in 6 naturally SIV-infected SMs by treating with humanized anti-CD4 mAb (Cdr-OKT4A-huIgG1). [CD4.sup.+] T cells were depleted almost completely in blood and BM and at variable levels in mucosal tissues and LNs. No marked depletion of [CD14.sup.+] monocytes was observed. Importantly, [CD4.sup.+] T cell depletion was associated with a rapid, significant decline in viral load, which returned to baseline level at day 30-45, coincident with an increased fraction of proliferating and activated [CD4.sup.+] T cells. Throughout the study, virus replication correlated with the level of proliferating [CD4.sup.+] T cells. [CD4.sup.+] T cell depletion did not induce any changes in the fraction of Tregs or the level of SIV-specific [CD8.sup.+] T cells. Our results suggest that the availability of activated [CD4.sup.+] T cells, rather than immune control of SIV replication, is the main determinant of set-point viral load during natural SIV infection of SMs., Introduction The HIV epidemic in humans arose after zoonotic transmission of simian [CD4.sup.+] T cell tropic lentiviruses, which naturally infect a range of African monkey host species and are now [...]

Arterial spin labeling (ASL) is a noninvasive magnetic resonance imaging (MRI) technique for microvascular blood flow measurement. We used a continuous ASL scheme (CASL) to investigate the hyperemic flow difference between major muscle groups in human extremities. Twentyfour healthy subjects with no evidence of vascular disease were recruited. MRI was conducted on a 3.0 Tesla Siemens Trio whole body system with a transmit/receive knee coil. A nonmagnetic orthopedic tourniquet system was used to create a 5-min period of ischemia followed by a period of hyperemic flow (occlusion pressure = 250 mmHg). CASL imaging, lasting from 2 min before cuff inflation to 3 min after cuff deflation, was performed on the midcalf, midfoot, and midforearm in separate sessions from which blood flow was quantified with an effective temporal resolution of 16 s. When muscles in the same anatomic location were compared, hyperemic flow was found to be significantly higher in the compartments containing muscles known to have relatively higher slow-twitch type I fiber compositions, such as the soleus muscle in the calf and the extensors in the forearm. In the foot, the plantar flexors exhibited a slightly delayed hyperemic response relative to that of the dorsal compartment, but no betweengroup flow difference was observed. These results demonstrate that CASL is sensitive to flow heterogeneity between diverse muscle groups and that nonuniform hyperemic flow patterns following an ischemic paradigm correlate with relative fiber-type predominance. skeletal muscle; magnetic resonance imaging

Byline: Norma G. Cuellar, DSN, RN (School of Nursing at the University of Pennsylvania, ncuellar@nursing.upenn.edu); Sarah J. Ratcliffe, PhD (Center for Clinical Epidemiology and Biostatistics School of Medicine at the [...]

Recent studies have identified sex differences in heart function that may affect the risk of developing heart failure. We hypothesized that there are fundamental differences in calcium (Ca) regulation in cardiac myocytes of males and premenopausal females. Isometric force transients (n = 45) were measured at various stimulation frequencies to define the force frequency responses (FFR) (0.5, 1.0, 1.5, and 2.0 Hz) during either changes in bath Ca ([[Ca].sub.o]) (1.0, 1.75, 3.5, and 7.0 mM) or length-tension (20, 40, 60, 80, and 100% [L.sub.max]) in right ventricle trabeculae from normal male (MT) and premenopausal female (FT) cats. Force-Ca measurements were also obtained in chemically skinned trabeculae. Under basal conditions (0.5 Hz, 1.75 mM Ca, 80% [L.sub.max]) both MT and FT achieved similar developed forces (DF) (MT 11 [+ or -] 1, FT = 10 [+ or -] 1 mN/[mm.sup.2]). At low rates and lengths, there is no sex difference. At higher preloads and rates, there is a separation in DF in MT and FT. At basal [[Ca].sub.o] both MT and FT exhibited positive FFR (2.0 Hz, 1.75 mM Ca: MT 38 [+ or -] 3, FT 21 [+ or -] 4 mN/[mm.sup.2]); however, at higher [[Ca].sub.o], MT achieved greater DF (2.0 Hz, 7.0 mM Ca: MT 40 [+ or -] 3 and FT = 24 [+ or -] 4 mN/[mm.sup.2]). We detected no sex difference in myofilament Ca sensitivity at a sarcomere length of 2.1 [micro]m. However, rapid cooling contractures indicated greater sarcoplasmic reticulum (SR) Ca load in MT at higher frequencies. Despite virtually identical contractile performance under basal conditions, significant sex differences emerge under conditions of increased physiological stress. Given the lack of sex differences in myofilament Ca sensitivity, these studies suggest fundamental sex differences in cellular Ca regulation to achieve contractile reserve, with myocardium from males exhibiting higher SR Ca load. myocardium; force-frequency response; length-tension relationship; myofilament calcium sensitivity; sarcoplasmic reticulum calcium load

Pattern-mixture models are frequently used for longitudinal data analysis with dropouts because they do not require explicit specification of the dropout mechanism. These models stratify the data according to time to dropout and formulate a model for each stratum. This usually results in underindentifiability, because we need to estimate many pattern-specific parameters even though the eventual interest is usually on the marginal parameters. In this article we extend this framework to a random pattern-mixture model, where the pattern-specific parameters are treated as nuisance parameters and modeled as random instead of fixed. The pattern is defined according to a surrogate for the dropout process. A constraint is then put on the pattern by linking it to the time to dropout using a random-effects survival model. We assume, conditional on the latent pattern effects, that the longitudinal outcome and the dropout process are independent. This model retains the robustness of the traditional pattern-mixture models, while avoiding the overparameterization problem. When we define each subject as a separate stratum, this model reduces to the shared parameter model. Maximum likelihood estimates are obtained using an EM Newton-Raphson algorithm. We apply the method to the depression data from the Prevention of Suicide in Primary Care Elderly Collaborative Trial (PROSPECT). We show when the dropout information is adjusted for under the proposed model, the treatment seems to reduce depression in the elderly. KEY WORDS: Dropout; EM algorithm; Mixed-effects model; Pattern-mixture mode., 1. INTRODUCTION Many longitudinal studies suffer from attrition, which can cause bias in the analysis if the dropouts are informative. To account for informative dropout, a number of model-based approaches [...]

The mechanisms underlying possible increased HIV-1 acquisition in adenovirus 5 (Ad5)-seropositive subjects vaccinated with Ad5-HIV-1 vectors in the Merck STEP trial remain unclear. We find that Ad5 serostatus does not predict Ad5-specific [CD4.sup.+] T cell frequency, and we did not observe durable significant differences in Ad5-specific [CD4.sup.+] T cells between Ad5-seropositive and Ad5-seronegative subjects after vaccination. These findings indicate no causative role for Ad5-specific [CD4.sup.+] T cells in increasing HIV-1 susceptibility in the STEP trial., Post hoc analysis of the Merck STEP trial showed that vaccination with an Ad5 vector-based HIV-1 vaccine was associated with increased HIV-1 acquisition rates in volunteers with baseline Ad5-neutralizing antibody [...]

Background. Both underweight and obesity have been suggested as risk factors for pressure ulcers (PU) development, although data are limited. Our aim was to evaluate the odds of PU in underweight and obese, relative to optimal weight patients. Methods. Secondary data analysis of a prospective cohort study of risk factors for PU on admission or by hospital day 3 in 3214 elderly patients admitted during 1998-2001 to two hospitals in Philadelphia, Pennsylvania. Results. Patients who were underweight had greater odds of developing PU (adjusted odds ratio [OR] = 1.8, 95% confidence interval [CI], 1.2-2.6). Patients who were obese had reduced odds (adjusted OR = 0.7, 95% CI, 0.4-1.0), and those with severe obesity had the lowest odds of PU (adjusted OR = 0.1, 95% CI, 0.01-0.6). Conclusions. These data suggest that extra body fat reduces the risk of PU in elderly hospitalized patients.