LEUKOCYTE KINETICS IN THE MICROCIRCULATION

白细胞与微血管内皮细胞的黏附和迁移 进入间质是炎症反应的标志，即 尤其是在败血症、休克和肺炎发作中有害 缺血/再灌流。我们已经能够在之前的演示中展示 研究表明，白细胞在微循环中以 毛细血管堵塞和毛细血管后附着于内皮 构成了组织动态平衡被破坏的一个关键方面。我们的过去 主要集中在血管内事件的研究将是 扩展以探索不同白细胞在组织破坏中的作用 在细胞跨微血管壁迁移期间和 在间质内的变形虫迁移过程中。我们建议的研究 旨在提供白细胞过程中关键事件的详细信息 利用新开发的数字荧光技术，介导组织损伤 大鼠选定组织的活体显微镜方法。我们的 假说认为，激活的白细胞在组织中迁移， 激活的内皮细胞作为自由基介导源 刺激后组织损伤。过氧化氢荧光标记物 形成、线粒体功能和细胞死亡将被用于 与延时显微摄影相结合，记录连续的细节 与组织中的白细胞迁移相关的事件。这个 涉及的膜黏附机制(整合素和选择素) 在间隙中的迁移将被调查在选定的 刺激器。氧自由基产生的机制 自由基及其对实质细胞死亡的后果将是 首次在体内以高光学分辨率进行量化 已确认身份。在中性粒细胞和血管内相互作用过程中 铁催化的羟基自由基对内皮细胞的过氧化作用 形成发生在两者之间的密切接触区域 细胞膜。这一机制将在体内进行探索 白细胞迁移到间质中的情况 对不同的促炎刺激物的反应。一个人经常观察 在白细胞穿过微血管壁迁移的过程中， 微量出血性红细胞素质的发展与血液病的形成 红细胞池的间质。这种现象已在#年观察到 许多临床情况，但其潜在的细胞和分子 机制尚不清楚。这是我们的假设，形成的微观- 出血需要白细胞的初始黏附和滞留，以及 红细胞逃逸到间质中与铁有关 ···催化··· 过氧化和细胞死亡。白细胞在体内的作用机制 发育型毛孔大到足以让红血球逃逸 使用活体和电子显微镜结合 模特儿。过氧化产物的产生，间质中的细胞死亡 微小出血和结缔组织变性的存在 将利用数字荧光显微镜对细胞进行研究 活着。沿着这些思路的系统计划将有助于确定关键 在激活的情况下导致组织损伤的机制 白细胞和内皮细胞。

The attachment of leukocytes to microvascular endothelium and migration into the interstitium is the hallmark of the inflammatory reaction that is especially deleterious in sepsis, shock, and episodes of ischemia/reperfusion. We have been able to demonstrate in previous studies that leukocyte entrapment in the microcirculation in the form of capillary plugging and post-capillary attachment to the endothelium constitutes a key facet of the disruption of tissue homeostasis. Our past studies, which were focused largely on intravascular events, will be expanded to explore the role of different leukocytes in tissue breakdown during the period of cell migration across the wall of microvessels and during amoeboid migration within the interstitium. Our proposed studies are designed to provide details of the key events during leukocyte mediated tissue injury, utilizing a newly developed digital fluorescent intravital microscopy approach in selected tissues of the rat. Our hypothesis proposes that activated leukocytes migrating in the tissue and activated endothelial cells serve as sources for free radical mediated tissue injury after stimulation. Fluorescent markers for peroxide formation, mitochondrial function and cell death will be utilized in conjunction with time-lapse microphotography to record sequential details of the events associated with leukocyte migration in the tissue. The membrane adhesion mechanisms (integrins and selectins) that are involved in interstitial migration will be investigated in the presence of selected stimulators. The mechanisms responsible for the production of oxygen free radicals and their consequences for parenchymal cell death will be quantified the first time in vivo at high optical resolution and identified. During the intravascular interaction between neutrophils and endothelial cells, peroxidation by iron catalyzed hydroxyl radical formation takes place in the region of close contact between the two cellular membranes. This mechanism will be explored in vivo under conditions where leukocytes are migrating into the interstitium in response to different proinflammatory stimulators. One observes regularly during migration of leukocytes across the microvascular wall, the development of micro-hemorrhagic erythrocyte diathesis and formation of interstitial pools of red cells. This phenomenon has been observed in many clinical situations but its underlying cellular and molecular mechanisms are unexplored. It is our hypothesis that formation of micro- hemorrhages requires an initial adhesion and diapedesis of leukocytes, and that red cell escape into the interstitium is associated with iron catalyzed hydroxyl radical formation and in turn enhanced parenchymal peroxidation and cell death. The mechanisms by which leukocytes in diapedesis form pores large enough for red cell escape will be investigated using intravital and electron microscopy in combination with modeling. The production of peroxides, cell death in the interstitium in the presence of micro-hemorrhages, and degeneration of connective tissue cells will be investigated utilizing digital fluorescent microscopy in vivo. A systematic program along these lines will serve to identify key mechanisms that lead to tissue damage in the presence of activated leukocytes and endothelial cells.