Biomedical subjects

John G Esposito

Publications and source records attributed to John G Esposito.

5 recordsLinked to original sources

PubMed2006

Comparison of body composition assessment methods in patients with human immunodeficiency virus-associated wasting receiving growth hormone.

CONTEXT: Bioelectrical impedance spectroscopy (BIS) and skinfold anthropometry (SKF) have been used to monitor body composition among patients with HIV wasting; however, validation of these techniques during recombinant human GH (rhGH) treatment has not been performed. OBJECTIVE: Our objective was to evaluate the degree of agreement between criterion measurements of dual-energy x-ray absorptiometry (DXA) and those of BIS and SKF in patients with HIV wasting treated with rhGH. DESIGN AND SETTING: We conducted a randomized, double-blinded, placebo-controlled, two-period crossover trial at the University of Toronto and Mount Sinai Hospital (Toronto, Canada). PATIENTS: A referred sample of 27 community-dwelling men with HIV-associated weight loss (> or =10% over preceding 12 months) despite optimal antiretroviral therapy participated in the study. INTERVENTION: Intervention was one daily injection of rhGH (6 mg) or placebo self-administered for 3 months in a crossover fashion with a 3-month washout. MAIN OUTCOME MEASURES: Fat-free mass (FFM) and fat mass (FM) were measured by BIS, SKF, and DXA before and after rhGH and placebo treatment. RESULTS: FFM(BIS) was not significantly different from FFM(DXA) after rhGH treatment (P = 0.10). Mean differences (bias +/- sd) according to Bland-Altman analysis were smaller for SKF than for BIS (P < 0.05) at all time points, yet treatment-induced change in FM was better detected with BIS than with SKF. BIS estimates of FFM and FM showed better agreement with those of DXA after rhGH treatment (1.6 +/- 4.6 kg and -2.1 +/- 3.9 kg) compared with baseline (3.8 +/- 3.5 kg and -4.1 +/- 3.6 kg) and placebo (2.7 +/- 4.4 kg and -3.1 +/- 4.6) (P < 0.05). BIS overestimated and SKF underestimated the treatment-induced changes in FFM and FM. CONCLUSIONS: SKF was more accurate than BIS when measuring body composition in patients with HIV wasting before and after rhGH treatment; nonetheless, the accuracy of BIS increased after treatment. Change in FM because of treatment was not accurately assessed with SKF.

Absorptiometry, Photon↗

PubMed2005

Anabolic growth hormone action improves submaximal measures of physical performance in patients with HIV-associated wasting.

Growth hormone (GH) treatment reverses the muscle loss allegedly responsible for diminished aerobic capacity and increased fatigue in patients with HIV-associated wasting. This study examined whether submaximal measures of physical performance can be used as objective measures of the functional impact of GH treatment-induced anabolism. We randomized 27 HIV-positive men [mean (SD) age, 43.9 (7.2) yr; body mass, 71.9 (10.4) kg; BMI, 23.1 (2.8) kg/m2] with unintentional weight loss despite antiretroviral therapy to receive GH (6 mg) or placebo in a double-blinded, placebo-controlled, cross-over trial with a 3-mo washout. Lean body mass (LBM), maximum oxygen uptake (Vo2 peak), ventilatory threshold (VeT), 6-min walk test (6MWT) distance and work, profile of mood states (POMS) fatigue and vigor scores, and Nottingham health profile (NHP) energy and physical mobility scores were measured. LBM significantly increased after 3 mo of GH treatment vs. placebo (means +/- SE, 3.7 +/- 0.6 vs. 0.3 +/- 0.4 kg; P < 0.001). VeT significantly improved (17.6 +/- 3.7 vs. -5.9 +/- 2.5%; P < 0.001), but Vo2 peak did not change significantly. 6MWT distance improved (24.9 +/- 9.7 vs. 19.9 +/- 11.6 m; P > 0.05) and 6MWT work increased significantly more after 3 mo of GH treatment (33.3 +/- 8.8 vs. 16.5 +/- 7.5 kJ; P < 0.05). POMS scores of fatigue and vigor and the NHP score of energy improved, yet the changes were not statistically significant. GH treatment improved VeT linearly to the increase in LBM (r =0.43, P = 0.037) and 6MWT work (r = 0.51, P = 0.008), and the increase in 6MWT work correlated with increase in LBM (r = 0.45, P = 0.024). Improvement in 6MWT work above the median (27.3 kJ) showed a decrease in fatigue (r = -0.62, P = 0.024). We concluded that GH treatment-induced LBM gains in HIV-associated wasting were functionally relevant, as determined by effort-independent submaximal measures of cardiopulmonary exercise testing.

Adult↗

PubMed2004

Growth hormone treatment improves peripheral muscle oxygen extraction-utilization during exercise in patients with human immunodeficiency virus-associated wasting: a randomized controlled trial.

The arteriovenous oxygen difference (a-vO(2) difference), a measure of peripheral muscle oxygen extraction-utilization during exercise, is reduced in antiretroviral-treated patients with human immunodeficiency virus (HIV), thus causing a shift in the cardiac output-oxygen consumption (Q-VO(2)) relationship. We investigated the impact of recombinant human GH (rhGH) treatment on a-vO(2) difference and the Q-VO(2) relationship during submaximal exercise by randomizing 12 HIV-infected patients (mean +/- sem: age, 43.3 +/- 1.5 yr; body mass, 69.5 +/- 2.9 kg; body mass index, 22.4 +/- 0.9 kg/m(2); maximum oxygen consumption, 33.6 +/- 1.5 ml/kg x min), with documented unintentional weight loss (>or=10% within the preceding 12 months) despite antiretroviral therapy, to receive 3 months of rhGH (6 mg/d) in a double-blind, placebo-controlled, cross-over trial. We assessed Q (determined noninvasively using CO(2) rebreathing), and subsequently a-vO(2) difference, from Q-VO(2) relationships. At study entry, the mean slope (8.1 +/- 1.0 liters/min x 1-liter increase in VO(2)) and intercept (3.1 +/- 1.3 liters/min), generated from each patient's Q-VO(2) relationship, were greater and lower, respectively, than those reported for healthy individuals (6.0 and 4.0, respectively), thereby indicating a deficit in the a-vO(2) difference. After 3 months of rhGH treatment, the slope decreased to 7.0, and the intercept increased to 3.5. After 1 month of rhGH treatment, the a-vO(2) difference (at a VO(2) of 1250 ml/min) significantly (P < 0.05) increased (17.1 +/- 8.9%) from baseline (9.92 +/- 0.51 ml/dl) and remained elevated (10.39 +/- 0.48 ml/dl) after 3 months of treatment. No significant changes were seen with placebo. Therefore, treatment with rhGH leads to an improvement in peripheral muscle oxygen extraction-utilization and the Q-VO(2) relationship during exercise in patients with HIV-associated wasting despite antiretroviral therapy.

Adult↗

PubMed2003

Exercise training benefits growth hormone (GH)-deficient adults in the absence or presence of GH treatment.

Reduced aerobic capacity is a prominent manifestation among patients with GH deficiency (GHD). Exercise training may improve the physiological capacity to undertake aerobic activity. The ability of patients with GHD to participate in and benefit from a structured program of aerobic exercise with or without replacement recombinant human GH (rhGH) was investigated. We examined the effect of aerobic training on cycle ergometers in a double-blind crossover trial. Ten patients with GHD trained for 3 months with rhGH (6 microg/kg.d) or placebo, stopped both exercise and drug for 2 months, and resumed training for another 3 months with the other agent. Peak oxygen uptake (VO(2)peak) and ventilation threshold (VeT) were measured during a progressive cycle ergometer test to fatigue or symptom-limited maximum. Serum IGF-I levels were monitored to assess compliance with GH treatment. VO(2)peak was low at the two baseline measures (B1, 19.3 +/- 5.5; B2, 19.9 +/- 6.9 ml/kg.min; normal, approximately 30 ml/kg.min) as was VeT (B1, 11.6 +/- 2.2 ml/kg.min; B2, 11.7 +/- 2.6 ml/kg.min; normal, approximately 16 ml/kg.min). Exercise training increased VeT with (8.6%) or without (9.4%) rhGH treatment. Similarly, exercise training resulted in significant reduction in submaximal heart rate in the presence (-5 +/- 4 beats per minute; P < 0.05) or absence of rhGH treatment (-4 +/- 4 beats per minute; P < 0.05). Peak oxygen uptake was not significantly affected by training with or without rhGH treatment. Our findings suggest that exercise training is a feasible intervention in GH-deficient adults that can measurably improve their submaximal responses to exercise. The beneficial effects of exercise can mimic and are not additive to the effects of GH treatment alone.

Adult↗

PubMed2002

Sex differences in performance on three novel continuous response tasks.

The Dynavision apparatus was used to assess psychomotor differences between men and women first-time users. Subjects, 50 men and 76 women, were tested on three 60-sec. Dynavision response tasks of graded difficulty. An analysis of variance with repeated measures indicated that men performed significantly better than women on all tasks. Performances on all tasks were also significantly different from each other within both sexes (p < or = .05). Furthermore, a significant interaction between sex and task was based on a greater drop in performance on the most complex task for women than for men.

Female↗