Body composition of HIV-infected male adults with wasting syndrome.

Chronic weight loss is a common characteristic of HIV infection; its full etiology remains unknown. We report body composition measurements for 39 adult males with wt loss >= 10% or a body mass index (BMI) below 19.8 kg • m-2 while receiving stable antiretroviral therapy, and no recent history of opportunistic infection, malignancy, Kaposi sarcoma, or therapy with anabolic agents. CD4+ counts ranged from 2 to 531; 30 subjects having counts <= 200. Body composition was measured by 40K counting, dual-energy X-ray absorptiometry (DXA), and anthropometry. The reference body composition measures were total body potassium (TBK), lean tissue mass (LEAN), fat mass (FAT), and percentage body fat (%FAT). In addition, nutritional assessment was based on a 2-d food diary. The mean TBK was 90.2% ± 10.8% of normal controls, while the %FAT averaged only 14.4% ± 5.3%, also below the normal range. Reasonable estimates of these body composition compartments were obtained using a combination of BMI, mid-arm circumference (MAC), and triceps skinfold measurements (TSF).

Methylated niacin derivatives in plasma and urine after an oral dose of nicotinamide given to subjects fed a low-methionine diet.

Five healthy males, age 25-32 y, were fed in sequence a diet of ordinary foods (10 d, PI), a low-methionine diet (285 mg/d, 14 d, PII), and an adequate-methionine diet (725 mg/d, 7 d, PIII). Diets contained 9 g nitrogen (N) per day with soy protein and synthetic L-amino acids as the N sources in PII and PIII. In PII, subjects were in negative N balance whereas, in PIII, four subjects were in positive N balance. On the last day of each period, fasting subjects ingested a dose of nicotinamide (NAM, 102 mumol/kg body wt). Plasma and urine samples were analyzed for methylated derivatives of NAM by high-performance liquid chromatography (HPLC) methods. Mean values of methylated metabolites in urine from the three diet periods (for four subjects in N balance during PIII) were not different (59.8, 56.7, and 59.9 mumol/(kg body wt X 24 h) for PI, PII, and PIII, respectively). Plasma values of these metabolites also were similar. Results suggest that during a 2-wk period of negative N balance due to a low-methionine intake hepatic methylation processes are not impaired. These processes appear to have a higher metabolic priority than maintenance of the net protein synthesis rate.