CALIBER OF ALVEOLAR SEPTAL MICROVESSELS IN ZONE 1

描述：（改编自申请人摘要） 研究人员建议测量的功能口径的 肺泡隔微血管合胞体在离体大鼠肺1区。 在区域1中，肺充气压力超过肺动脉和肺动脉压力。 静脉压力，以前曾假设这会导致 肺泡隔微血管完全塌陷。 许多生理 这些研究都是基于这个假设。 肺可以在1区灌注， 通常的解释是这是通过齿槽角发生的 血管，绕过中隔微血管。 然而，猜测是， 开始出现隔膜微血管可能至少 在区域1中可部分灌注。 如果是这样， 对先前研究的影响，其中假设， 这些 船只被摧毁。 为了解决这个问题，研究人员建议， 测量肺泡隔微血管的功能口径 合胞体在1区。 测量将通过灌注分离的 具有特定尺寸（0.010 - 10.0）的荧光乳胶颗粒的大鼠肺 微米直径）。 肺将在特定区域1下灌注 条件，每个肺 充满了单一的 然后将肺迅速冷冻，并将组织学样本 将使用计算机化激光共聚焦荧光 显微镜 从数字图像，乳胶颗粒密度将被测量 在个别肺泡隔。将比较肺灌注的数据 用不同的颗粒直径，并用于计算功能 隔膜微血管合胞体口径的条件下， 肺灌注。 将以以下几种组合制备肺： 灌注和膨胀压力，以确定间隔合胞体 口径在通过区域1和过渡到区域2的过程中发生变化， 充气压力小于肺动脉压力，但是 高于肺静脉压。 隔合胞体口径 也将在液体膨胀的大鼠肺中测量，其中表面 隔膜空气-水界面的张力将不存在。 结果 会告诉我们表面张力是否在维持间隔 在区域1中的充气肺中的灌注性。

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.