DETERMINANTS OF MUSCLE MAXIMAL O2 UPTAKE AND PERFORMANCE

描述：（改编自申请人摘要）：本研究的目的 研究旨在阐明限制最大O2消耗量的因素 （V02max）和工作骨骼肌的性能。 1)的假设 V02最大值可能受到氧气扩散能力的限制， 将使用离体原位犬检测外周组织 腓肠肌模型和人的分离的膝伸肌模型。 建立了一个考虑扩散限制的数学模型 从菲克扩散定律和菲克原理的结合。 a. 这个模型将被用来预测各种实验的结果， 通过降低动脉P02、贫血和 缺血 特殊实验中，）2输送（肌肉血流量 X动脉O2含量）将在不同的条件之间保持相等。 低氧血症、贫血和肌肉血流量将用于两种动物 和人类研究，试图将灌注限制与 扩散限制 B。因为肌肉血流量V02异质性 可以模拟O2扩散限制，组织异质性的问题将 也可以在犬腓肠肌模型中使用阶跃变化进行研究 在惰性气体和动脉血的O2水平下， 静脉反应，使用研究肺 异质性 2)决定肌肉功能的几个因素 还将调查高强度工作期间的表现。 a.的 将测量渐进工作期间的NAD氧化还原状态，以确定 组织氧合及其代谢控制。 B。的作用 糖酵解在紧张的工作和增加的影响 对收缩功能和疲劳的激活-放松周期将是 研究了 这些实验还将提供有关 糖酵解产生的ATP的量， 功能协调发展的 C.在所有的实验中，其中O2输送是 操纵，疲劳的发展将沿着变化进行研究 血液和肌肉酸碱平衡。 D.最后，潜在作用 减容术后肌微循环粒细胞堵塞 还将研究原位最大血流量。

DESCRIPTION: (Adapted from applicant's abstract): The objective of this study is to elucidate the factors that limit maximal 02 consumption (V02max) and performance in working skeletal muscle. 1) The hypothesis that V02 max can be limited by the capacity for 02 diffusion in the peripheral tissue will be tested using an isolated, in situ canine gastrocnemius model, and the isolated knee extensor muscle model in humans. A mathematical model incorporating diffusion limitation has been developed from a combination of Fick's law of diffusion and the Fick principle. A. This model will be used to predict the outcome of various experiments in which 02 delivery is altered through lowered arterial P02, anemia, and ischemia. Special experiments in which the )2 delivery (muscle blood flow X arterial 02 content) will be kept equal between varied conditions of hypoxemia, anemia, and muscle blood flow will be used in both the animal and human studies in an attempt to separate perfusion limitation from diffusion limitation. B. Because muscle blood flow to V02 heterogeneity can mimic 02 diffusion limitation, the problem of tissue heterogeneity will also be investigated in the canine gastrocnemius model using step changes in inert gas and 02 levels of arterial blood and following the muscle venous responses, using methodology developed investigating for pulmonary heterogeneity. 2) Several factors that determine muscle function and performance during high-intensity work will also be investigated. A. The NAD redox state during progressive work will be measured to determine tissue oxygenation and its control of metabolism. B. The role of glycolysis during intense work and the impact of increased activation-relaxation cycles on contractile function and fatigue will be investigated. These experiments will also provide information concerning the amount of ATP produced by glycolysis that is used for membrane functions. C. In all of the experiments in which 02 delivery is manipulated, the development of fatigue will be studied along with changes in blood and muscle acid-base balance. D) Finally, the potential role of granulocyte plugging of muscle microcirculatin after surgery in reducing in situ maximal blood flow will also be investigated.