CALIBER OF ALVEOLAR SEPTAL MICROVESSELS IN ZONE 1

描述：(改编自申请人的摘要) 研究人员建议测量心脏的功能口径 1区大鼠离体肺的肺泡间隔微血管合体。 在第一区，肺膨胀压超过了肺动脉和 静脉压力，此前有人认为这会导致 肺泡间隔微血管完全塌陷。无数生理上的 研究就是基于这一假设。肺可以在1区进行灌流， 通常的解释是，这是通过肺泡角发生的。 血管，绕过隔膜微血管。然而，猜测是 开始出现间隔微血管可能至少是 在区域1中部分可灌装。如果是这样的话，它具有显著的 对以前的研究的影响，在这些研究中，假设这些 船只坍塌。为了解决这个问题，调查人员提议 肺泡间隔微血管功能口径的测量 合胞体在1区。测量将通过灌流分离的 大鼠肺中含有特定大小的荧光乳胶颗粒(0.010-10.0 微米直径)。肺将在特定区域1下进行灌流 条件下，每个肺都灌入一种单一的 直径。然后肺将被迅速冰冻，组织学样本 将使用计算机化的激光共聚焦荧光进行检查 显微镜。从数字图像中，将测量乳胶颗粒密度 在个体肺泡间隔中。数据将与来自肺血流灌注的数据进行比较 不同的颗粒直径，并用于计算泛函 间隔部微血管合体口径 肺都被灌流了。肺将以几种组合的形式准备 血流灌注和充气压力确定间隔合胞如何 口径通过1区并在过渡到2区期间发生变化，其中 充气压力小于肺动脉压，但 高于肺静脉压。间隔合胞体口径 还会在液体充气的大鼠肺中测量，那里的表面 隔膜的空气-水界面将不会有张力。结果是 将告诉我们表面张力是否在维持间隔中起作用 在空气中的灌注性在区域1中充气肺。

DESCRIPTION: (Adapted from the applicant's abstract) The investigators propose to measure the functional caliber of the alveolar septal microvascular syncytium in isolated rat lungs in zone 1. In zone 1, lung inflation pressure exceeds both pulmonary arterial and venous pressures and it has previously been assumed that this causes the alveolar septal microvessels to fully collapse. Numerous physiological studies are based on this assumption. Lungs can be perfused in zone 1, and the usual explanation is that this occurs by way of alveolar corner vessels, which bypass the septal microvessels. However, speculation is beginning to emerge that the septal microvessels may be at least partially perfusable in zone 1. If this is so it has significant implications for previous studies in which it was assumed that these vessels were collapsed. To address this, the investigators propose to measure the functional caliber of the alveolar septal microvascular syncytium in zone 1. The measurements will be made by perfusing isolated rat lungs with fluorescent latex particles of specific size (0.010 - 10.0 microns diameter). Lungs will be perfused under specific zone 1 conditions, with each lung being perfused with particles of a single diameter.The lungs will then be frozen rapidly, and histological samples will be examined using a computerized laser confocal fluorescence microscope. From digital images, latex particle density will be measured in individual alveolar septa. Data will be compared from lungs perfused with different particle diameters and used to calculate the functional septal microvascular syncytial caliber under the conditions in which the lungs were perfused. Lungs will be prepared in several combinations of perfusion and inflation pressures to determine how the septal syncytial caliber changes through zone 1 and during transition into zone 2, where the inflation pressure is less than the pulmonary artery pressure, but greater than the pulmonary venous pressure. Septal syncytial calibers will also be measured in liquid inflated rat lungs, where the surface tension of the septal air-water interface will be absent. The results will tell us if surface tension plays a role in maintaining septal perfusability in air inflated lungs in zone 1.