GUT ISCHEMIA: OXYGEN DELIVERY AND SUPEROXIDE RADICALS

肠缺血的死亡率接近100%，占 这个国家3%的死亡人数。已经引起了相当大的关注 用血管扩张剂改善肠道血流。然而， 低流量本身不同于低氧对粘膜的贡献 伤势还没有得到明确的证明。因此，我们建议 探讨氧输送和血流在脑血管疾病发生中的作用 犬回肠离体段黏膜损伤的实验研究。四个系列 将进行实验。高、中、低浓度静脉血灌流 低含氧量将与动脉血液灌流在 正常流量水平。用动脉血进行低流量灌流将 与生理盐水腔内灌注相结合， 葡萄糖负荷以刺激新陈代谢，并与氟碳乳剂 加强氧气输送。动脉血的低流量灌流效应 含有氟碳乳剂或经过处理的六磷酸肌醇 将测定红细胞增强血管氧输送的能力。这个 动脉内加入血管扩张剂的效果将在低血压期间确定。 压力和低流量灌流。血管阻力将被用作 局部循环反应的指数。血流分布在两地之间 每个肠段的粘膜/粘膜下和肌层区域将 由放射性核素微球测定。系列组织样本将会是 分析了三磷酸腺苷、黄嘌呤、次黄嘌呤、尿酸、无机磷、 乳酸/丙酮酸比值、谷草转氨酶、柠檬酸 合酶、β-葡萄糖苷酸酶和丙二醛 细胞毒性氧自由基与细胞形态改变的关系 与缺血有关。光、扫描和传输电子 显微镜将记录形态变化和扫描，并传输 电子显微镜将记录形态变化和扫描，以及 透射电子显微镜将记录形态变化和 细胞活动的时间进程。这些研究的结果将 对导致致命疾病的致病因素提供了新的见解 肠道循环功能不全的后果。

The mortality rate from intestinal ischemia is near 100% and accounts for 3% of the deaths in this country. Considerable attention has been directed to improvement of intestinal blood flow with vasodilator drugs. However, the contribution of low flow, per se, as distinct from hypoxia to mucosal injury has not been clearly demonstrated. Accordingly, we propose to investigate the roles of oxygen delivery and blood flow in the genesis of mucosal injury in isolated segments of canine ileum. Four series of experiments will be conducted. Perfusion with venous blood with high and low oxygen content will be contrasted with arterial blood perfusion at normal flow levels. Low flow perfusion with arterial blood will be combined with luminal perfusion with normal physiological saline, with a glucose load to stimulate metabolism and with a fluorocarbon emulsion to enhance oxygen delivery. Low flow perfusion effects of arterial blood containing either fluorocarbon emulsion or inositol hexaphosphate treated erythrocytes to enhance vascular oxygen delivery will be determined. The effects of added intrarterial vasodilators will be determined during low pressure and low flow perfusion. Vascular resistance will be used as an index of the local circulatory responses. Blood flow distribution between mucosal/submucosal and muscularis regions of each intestinal segment will be determined by radionuclide microspheres. Serial tissue samples will be analyzed for ATP, xanthine, hypoxanthine, uric acid, inorganic phosphate, lactate/pyruvate ratio, glutamate-oxaloacetate transaminase, citrate synthase, Beta-glucuronidase and malondialdehyde to estimate the involvement of cytotoxic oxygen radicals in the morphologic alterations associated with ischemia. Light, scanning, and transmission electron microscopy will document morphologic changes and scanning, and transmission electron microscopy will document morphologic changes and scanning, and transmission electron microscopy will document morphologic changes and the time course of the cellular events. The results of these studies will provide new insights of the causative factors which precipitate the fatal consequences of circulatory insufficiency in the intestine.