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Aging appears to attenuate leg blood flow during exercise; in contrast, such data are scant and do not support this contention in the arm. Therefore, to determine whether aging has differing effects on blood flow in the arm and leg, eight young (22 +/- 6 yr) and six old (71 +/- 15 yr) subjects separately performed dynamic knee extensor [0, 3, 6, 9 W; 20,(More)
Arm and leg vascular responsiveness to comparable shear stimuli during isolated dynamic exercise has not been assessed in humans. Consequently, six young cyclists performed incremental, intermittent handgrip exercise (arm) and knee-extensor exercise (leg) from 5 to 60% of maximal work rate (WR). Ultrasound Doppler measurements were taken in the brachial(More)
We measured leg blood flow (LBF), drew arterial-venous (A-V) blood samples, and calculated muscle O(2) consumption (VO(2)) during incremental cycle ergometry exercise [15, 30, and 99 W and maximal effort (maximal work rate, WR(max))] in nine sedentary young (20 +/- 1 yr) and nine sedentary old (70 +/- 2 yr) males. LBF was preserved in the old subjects at 15(More)
To determine the effect of age on quadriceps muscle blood flow (QMBF), leg vascular resistance (LVR), and maximum oxygen uptake (QVO2 max), a thermal dilution technique was used in conjunction with arterial and venous femoral blood sampling in six sedentary young (19.8 +/- 1.3 yr) and six sedentary old (66.5 +/- 2.1 yr) males during incremental knee(More)
The importance of the chromosome versus the gene as a causative agent in cancer formation has sparked a heated debate. This issue is directly related to two different schools of thought, namely the gene-centric or genome-centric paradigms of cancer research [1–3]. For decades we have essentially ignored the evolutionary nature of complex cancer systems due(More)
We measured leg blood flow (LBF), drew arterial-venous (a-v) blood samples, and calculated muscle O 2 consumption (VO 2), during incremental cycle ergometry exercise (15, 30, 99 W, and maximal effort (WR max)), in 9 sedentary younger (Y, 20 ± 1 yrs) and 9 sedentary older (O, 70 ± 2 yrs) males. LBF was preserved in the older subjects at 15 and 30 Watts.(More)
BACKGROUND AND PURPOSE Serotonin is a major regulator of structural brain plasticity, which may occur following cortical resection in humans. In this study we used positron emission tomography (PET) with alpha[11C]methyl-l-tryptophan (AMT) to evaluate serotonergic alterations in subcortical structures following cortical resection in children with(More)
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