EFFECTS OF EXERCISE AT HIGH ALTITUDE ON CARDIOPULMONARY FUNCTION

在最大努力下，藏族比汉族表现出更高的耗氧量、搏量、心输出量和最大通气量。藏族绝对耗氧量的厌氧阈值高于汉族。我们的结论是，长期暴露在低氧环境中会导致氧气运输的增加和有氧运动表现的改善。b)研究了高原终身藏族青少年与高原新汉族青少年氧转运的差异。我们发现，从出生到青春期暴露在高海拔地区会导致更高的氧运输效率和更好的有氧运动表现，这可能反映了对高海拔生活的成功适应。2)高原肺水肿的病理生理(a)我们以前已经表明，高原肺水肿易感受试者（HAPE-S）对缺氧的肺血管反应增强。我们研究了血浆内皮素-1水平与HAPE-S患者和健康对照者急性缺氧肺血管反应的关系。我们发现肺血管对急性缺氧反应的增加可能与内皮素-1的释放有关。b)测定4例HAPE患者支气管肺泡灌洗液中细胞因子的含量。IL-1*IL-6、II-8和TNFalpha水平明显升高，但恢复后很快恢复到正常范围或未检出。il -1 α、IL-10和p选择水平没有变化。这些结果表明，HAPE患者可能发生与ARDS几乎相同的炎症过程，但这些变化是短暂的。c)我们通过放射性同位素显像检查了HAPE易感受试者对缺氧的肺血流动力学反应。我们对hape易感组进行了通气-灌注显像，获得了功能图像的qv和V/Q，在低氧条件下肺血流量明显由肺下野向肺上野转移，但未观察到局部通气的明显变化。结果，它们出现了通气-灌注不匹配。d)我们研究了人类白细胞抗原DR-6是否具有HAPE的遗传易感性。DR-6在HAPE易感人群中出现频率增高，提示其肺循环体质异常，对缺氧和低氧血症有通气反应，遗传因素可能参与HAPE的发生。少

1) EFFECTS OF EXERCISE AT HIGH ALTITUDE ON CARDIOPULMONARY FUNCTIONa) To examine the difference for oxygen transport between Tibetan living for generations at high altitude a acclimatized Han newcomers to high altitude, we measured the ventilatory, circulatory, metabolic and gas exchanges function during exercise in 17 Tibetans and 19 Hans at the altitude of 3417m in China. At maximal effort, the Tibetans, compared with the Hans, showed higher O2 consumption, stroke volume, cardiac output, and the maximal ventilation. The anaerobic threshold for absolute O2 consumption for the Tibetan are highent for the Hans. We conclude that the lifelong exposure to an hypoxic environment has resulted in an increase in oxygen transport and improved aerobic exercise performance.b) The difference of oxygen transport between adolescents of lifelong Tibetans and acclimatized Han newcomers to high altitude was studied. We found that the exposure to high altitude from birth to adolescence resulted in an ef … More ficient oxygen transport and a greater aerobic exercise performance which may reflect a successful adaptation to life at high altitude.2) PATHOPHYSIOLOGY OF HIGH ALTITUDE PULMONARY EDEMAa) We have previously shown that high altitude pulmonary edema-susceptible subjects (HAPE-S) have an accentuated pulmonary vascular response to hypoxia. We investigated the relationship between plasma endothelin-1 levels and the acute hypoxic pulmonary vascular response in patients with HAPE-S and healthy control subjects. We found that the increased pulmonary vascular response to acute hypoxia in HAPE-S may n related to endothelin-1 release.b) The cytokines were measured in the bronchoalveolar lavage fluid from four patients with HAPE.The leves IL-1*IL-6, II-8, and TNFalpha were considerably increased but returned quickly to the normal ranges or wel not detected after recovery. The levels of IL-1alpha, IL-10, and P-selectinlevels didi not change. These rest suggest that an inflammatory process almost identical with ARDS may occur in HAPE,but that these changes transient.c) We examined the pulmonary hemodynamic response to hypoxia in HAPE susceptible subjects by radioisotop scintigraphy. We performed ventilation-perfusion scintigraphyand acquired functional images of Q V and V/Q the functional images, the pulmonary blood flow was significantly shifted from the lower lung field to the upp lung field under hypoxia but no significant change of regional ventilation was observed in the HAPE-susceptibl subjects. As a results, they showed ventilation-perfusion mismatch.d) We studied whether human leukocyte antigen DR-6 functions as agenetic predisposition to HAPE.The frequency of DR-6 was increased in the subjects susceptible to HAPE,which suggests that they have a constitutional abnormality in the pulmonary circulatory, and ventilatory responses to hypoxia and hyhobaria, and that genetic factors may be involved in the development of HAPE. Less