Effects of whey protein and resistance exercise on body cell mass, muscle strength, and quality of life in women with HIV.

OBJECTIVE: To determine the effects of whey protein, resistance exercise, and combined protein and exercise treatment on body cell mass (BCM), muscle strength, and quality of life (QOL) in HIV-infected women with reduced BCM. DESIGN AND SETTING: Prospective, randomized, controlled trial at a university hospital in New York City. METHODS: A volunteer sample of 30 HIV-infected women were randomized to whey protein (PRO), progressive resistance exercise (PRE), or combined treatment (PRO-PRE) for 14 weeks after a 6-week control period. The main outcome measures were body weight, BCM, skeletal muscle, fat mass, muscle strength, and QOL. RESULTS: There were no significant changes in BCM, strength, or QOL during the control period. PRO patients gained 3.6 kg (P = 0.001), and 2.5 kg fat (P = 0.002) with no change in BCM (0.5 kg; P = 0.07) or skeletal muscle (0.6 kg; P = 0.12). The PRE group increased BCM (0.74 kg;P = 0.03) and skeletal muscle (1.2 kg; P < 0.001) and decreased fat (1.7 kg; P = 0.02). PRO-PRE increased BCM (0.61 kg; P = 0.01) without change in skeletal muscle (0.6 kg; P = 0.30). Strength increased for both exercise groups (range, 40.6-95.3%; P < 0.001). The QOL physical activity score improved for PRE (P = 0.02) and worsened for PRO (P = 0.01). CONCLUSIONS: Resistance exercise significantly increased BCM, muscle mass, muscle strength, and QOL in HIV-infected women with reduced BCM. Whey protein had little effect on BCM accrual. Combined protein and exercise did not increase BCM in excess of gains achieved by exercise alone.

Interactions among sex, HIV infection, and fat redistribution.

The interactions among sex, HIV infection, and body fat redistribution are uncertain. We retrospectively compared total, subcutaneous, and visceral adipose tissue (TAT, SAT, VAT) contents, as determined by whole body MRI, in 85 HIV-infected persons, including 48 HIV-positive persons with self-reported changes in body shape, and matched healthy controls. The effect of sex on regional fat contents differed among HIV-infected persons with and without self-reported changes in body shape. Women without changes had significantly less SAT and TAT than did controls, while men with changes had significantly less SAT and TAT than did controls. Higher contents of VAT were found in both men and women with self-reported changes in body shape.

Weight loss in postmenopausal obesity: no adverse alterations in body composition and protein metabolism.

We sought to determine if decrements in the mass of fat-free body mass (FFM) and other lean tissue compartments, and related changes in protein metabolism, are appropriate for weight loss in obese older women. Subjects were 14 healthy weight-stable obese (BMI > or =30 kg/m(2)) postmenopausal women >55 yr who participated in a 16-wk, 1, 200 kcal/day nutritionally complete diet. Measures at baseline and 16 wk included FFM and appendicular lean soft tissue (LST) by dual-energy X-ray absorptiometry; body cell mass (BCM) by (40)K whole body counting; total body water (TBW) by tritium dilution; skeletal muscle (SM) by whole body MRI; and fasting whole body protein metabolism through L-[1-(13)C]leucine kinetics. Mean weight loss (+/-SD) was 9.6+/-3.0 kg (P<0.0001) or 10.7% of initial body weight. FFM decreased by 2.1+/-2.6 kg (P = 0.006), or 19.5% of weight loss, and did not differ from that reported (2.3+/-0.7 kg). Relative losses of SM, LST, TBW, and BCM were consistent with reductions in body weight and FFM. Changes in [(13)C]leucine flux, oxidation, and synthesis rates were not significant. Follow-up of 11 subjects at 23.7 +/-5.7 mo showed body weight and fat mass to be below baseline values; FFM was nonsignificantly reduced. Weight loss was accompanied by body composition and protein kinetic changes that appear appropriate for the magnitude of body mass change, thus failing to support the concern that diet-induced weight loss in obese postmenopausal women produces disproportionate LST losses.

Gender and ethnic differences in health behaviors and risk factors for coronary disease among urban teenagers: the PATH program.

OBJECTIVE: To assess gender and ethnic differences among teenagers in heart health behaviors, risk factors for coronary heart disease (CHD), and cardiovascular fitness. DESIGN: Observations consist of cross-sectional data collected prior to a school-based health promotion intervention program. PARTICIPANTS: Teenage girls (N = 865) and boys (N = 497) from three New York City high schools. The ethnic composition of this sample was 20% Asian-American, 40% African-American, 25% Hispanic, and 15% white. METHOD: Subjects were compared on the following: height, weight, body mass index, percentage body fat, total cholesterol, blood pressure, heart health knowledge, family history, socioeconomic status, dietary habits, smoking, physical activity, and estimated aerobic capacity. Differences were assessed with independent t tests, analysis of variance, and chi-square statistical techniques. RESULTS: Compared with girls, boys were more active and had higher estimated aerobic capacity, higher systolic blood pressure, and better self-perception of health. Compared with boys, girls had higher cholesterol, percentage body fat, and heart health knowledge scores and ate fewer foods high in saturated fat, cholesterol, salt, and simple sugars. Among girls, African-Americans had the highest blood pressure, cholesterol, body mass index, and intake of foods high in saturated fat, cholesterol, and sugar. Among boys, Hispanics had the highest body mass index and percentage body fat and the lowest heart health knowledge scores. White girls and white boys were the most frequent smokers. CONCLUSIONS: Poor health behaviors and risk factors for CHD occurred frequently among urban teenagers. In general, teenage girls had poorer health behaviors and a greater prevalence of risk factors than teenage boys, even though they scored better in heart health knowledge testing. Ethnic comparisons revealed poorer health behaviors and higher prevalence of risk factors in African-American and Hispanic teens compared with white and Asian-American teens. Results support the need for health promotion intervention among urban teenagers.

Fat distribution in HIV-infected patients reporting truncal enlargement quantified by whole-body magnetic resonance imaging.

BACKGROUND: Antiretroviral therapy has improved the prospects for people infected with HIV, but some develop a syndrome of profound body habitus and metabolic alterations that include truncal enlargement. OBJECTIVE: The purpose of this study was to define the body-composition changes associated with this syndrome by using techniques with the power to estimate regional body composition. DESIGN: We compared whole-body and regional skeletal muscle and adipose tissue contents measured by magnetic resonance imaging and dual-energy X-ray absorptiometry (DXA) in 26 HIV-infected patients and 26 matched control subjects. Twelve of the HIV-infected patients had evidence of truncal enlargement. RESULTS: HIV-infected men and women who noted truncal enlargement had similar amounts of skeletal muscle and subcutaneous adipose tissue but greater visceral adipose tissue than HIV-infected patients without truncal enlargement; these values were larger in men (P < 0.001) than in women (P = 0.08). The ratio of visceral to subcutaneous adipose tissue was greater in both men (P < 0.02) and women (P = 0.05) with truncal enlargement. Two subjects with MRI-confirmed visceral adiposity syndrome (VAS) were not taking protease inhibitors. CD4+ lymphocyte counts were higher (P < 0.001) and plasma viral burdens tended to be lower (P = 0.08) in HIV-infected patients with VAS. CONCLUSIONS: There was significantly more visceral adipose tissue in the subgroup of HIV-infected patients with truncal enlargement than in those without this sign. VAS occurs in both men and women, is associated with higher CD4+ lymphocyte counts and lower plasma HIV viral burdens, and is not limited to those receiving protease inhibitor therapy.

An approach to the physical basis of negative conductance in the squid axon.

In considering the problem of steady-state negative conductance in the squid axon from the standpoint of electrodiffusion, the following assumptions produce results which are in reasonable agreement with experimental observations: (1) The major ion distributions are not significantly perturbed by current flows (2) The electric field in the membrane is essentially uniform. (3) The membrane has certain properties appropriate to solids, particularly with respect to chemical potentials. (4) Na(+) and K(+) move according to a single-file interstitialcy migration mechanism and independently of each other. (5) The interaction energy of Na(+) with membrane sites is about 1.4 times that for K(+). Assumptions 1 and 2 are sufficient for the appearance of a negative conductance. Experimental test of the theory is possible and is specifically suggested.