We previously found that epinephrine, a mixed beta- and alpha-adrenoreceptor agonist, stimulates systemic and nonsplanchnic upper body free fatty acid (FFA) release but not lower body FFA release in healthy nonobese women. To evaluate the role of beta-adrenergic-mediated effects on this regional difference in lipolysis, we measured systemic, leg, and splanchnic FFA kinetics ([3H]palmitate) in seven healthy nonobese women before and during an intravenous isoproterenol infusion. Isoproterenol increased systemic palmitate flux (87 +/- 12 vs. 100 +/- 10 mumol/min, P < 0.05) but failed to affect leg [10.8 +/- 1.2 vs. 11.4 +/- 2.3 mumol/min, P = not significant (NS)] or splanchnic (10.8 +/- 3.2 vs. 10.0 +/- 1.8 mumol/min, P = NS) palmitate release. Upper body nonsplanchnic palmitate release increased from 56 +/- 14 to 71 +/- 10 mumol/min. Systemic O2 consumption increased (227 +/- 11 to 241 +/- 10 ml/min, P = 0.006) during isoproterenol infusion, as did leg (318 +/- 42 vs. 404 +/- 53 ml/min, P < 0.01) and splanchnic (827 +/- 104 vs. 970 +/- 108 ml/min, P < 0.05) plasma flow. These results suggest that lower body adipose tissue lipolysis in women is less sensitive or responsive than nonsplanchnic upper body adipose tissue to beta-adrenergic stimulation and that regional differences in alpha 2-adrenergic-receptor responses were not responsible for the similar regional differences we observed previously with epinephrine.
Jensen, Michael D., Tu T. Nguyen, A. Hernández Mijares, C. Michael Johnson, and Michael J. Murray. Effects of gender on resting leg blood flow: implications for measurement of regional substrate oxidation. J. Appl. Physiol. 84(1): 141–145, 1998.—These studies were designed to examine whether the respiratory quotient (RQ) of leg tissue (primarily skeletal muscle) would increase to a greater degree in women than in men during meal ingestion. We found that mean leg and systemic RQ values were similar in men under both basal and fed conditions, whereas the agreement was poor in women. In women, leg RQ values tended to be greater than the systemic RQ, whereas splanchnic RQ values tended to be lower than the systemic RQ. The possibility that measurement imprecision accounted for the different findings in women could not be excluded because the arteriovenous blood O 2 differences were almost twice as great in men as in women (53.7 ± 5.4 vs. 28.6 ± 2.9 ml of O 2 /l, respectively; P < 0.01), as were venoarterial blood CO 2 differences. The smaller arteriovenous differences in women appeared to limit our ability to accurately measure their leg RQ values. O 2 uptake relative to leg fat-free mass (FFM) was not different between men and women, whereas leg blood flow relative to leg FFM was greater in women than in men (55 ± 3 vs. 39 ± 2 ml ⋅ kg FFM −1 ⋅ min −1 , respectively; P < 0.001). These findings were confirmed by examining data from other studies conducted in our laboratory to create a larger data set. We conclude that resting leg blood flow in women is greater (relative to FFM) than in men, making it more difficult to accurately measure leg RQ in women.
Upper-body and lower-body adipocytes respond differently to physiological catecholamines in vitro. It is not known whether this is true in vivo or whether gender differences exist in the regional adipose tissue responses to epinephrine. These studies were therefore conducted to examine free fatty acid (FFA) release ([3H]palmitate) from lower-body (leg), splanchnic, and upper-body adipose tissue in normal-weight adult men (n = 8) and women (n = 7). In response to intravenous epinephrine (10 ng.kg-1.min-1), palmitate release increased (P < 0.01) in both men (168 +/- 10 to 221 +/- 15 mumol/min) and women (177 +/- 12 to 234 +/- 18 mumol/min). Basal leg palmitate release was similar in women and men (16.8 +/- 2.9 and 12.4 +/- 1.3 mumol/min, P = not significant) but doubled (P < 0.01) in response to epinephrine in men and was virtually unchanged in women. Splanchnic palmitate release increased (P < 0.05) in men (n = 6) but not in women (n = 6), whereas nonsplanchnic upper-body palmitate release increased more in women than in men. Upper-body (splanchnic and nonsplanchnic) palmitate release increased (P < 0.05) in both men and women in response to epinephrine. In summary, lower-body adipose tissue FFA release increased in response to epinephrine in men but not women, whereas upper-body palmitate release increased in both groups. These findings are consistent with some in vitro findings and suggest that catecholamine action may play a role in determining gender-based differences in body fat distribution.
This work presents a novel investigation of an NMR device to measure blood flow. Continuous-wave magnetic resonance scanners are now available for noninvasive peripheral blood flow measurements. The appearance of dedicated peripheral blood flow scanners in the clinical setting requires analysis of system performance. No reports were found that explore methods or results of clinical MR blood flow scanner performance evaluation. This work was undertaken to identify the testing procedures and characteristics of a clinical, dedicated NMR blood flow scanner. The dependence of flow measurement on tubing size, material, offset from isocenter, and angulation was examined. In addition, the precision and accuracy of the scanner were investigated. The results demonstrate a strong dependence between the measured blood flow and both the tube size and flow rate. The tube offset results exhibited a region of weak dependence in the center of the bore, which becomes stronger near the edge. The measured flow rate was found to be relatively insensitive to tube angles less than 30 degrees to 55 degrees. The repeatability was typically better than 5% and the table positioning was found to be highly accurate.
Eighteen patients received 1,250 mg of allopurinol riboside (AR) four times daily for 28 d. Nine of the patients concurrently received 500 mg probenecid (PB) four times daily. Cure was assessed clinically and parasitologically. Patients who had culture-positive and nonhealing lesions 3 mo after therapy received pentavalent antimony. Of the nine patients who received AR alone, four (44%) had clinical improvement at the end of therapy and two (22%) were culture-negative. A third patient became culture negative at 2 mo after therapy. The culture-negative patients were completely healed at 1 mo and remained so at 1 y after therapy. Of the nine patients who received AR plus PB, four had complete healing and two had clinical improvement at the end of therapy; however, all patients remained culture-positive. At 2-3 mo after therapy, six (67%) of the patients were completely healed, and of these, five (56%) were culture-negative. The drug was well-tolerated.
