INVIVO MEASUREMENTS OF APPARENT VISCOSITY AND MICROVESSEL HEMATOCRIT IN THE MESENTERY OF THE CAT
INVIVO MEASUREMENTS OF APPARENT VISCOSITY AND MICROVESSEL HEMATOCRIT IN THE MESENTERY OF THE CAT
复制标题
DOI：
10.1016/0026-2862(80)90050-3
复制
发表时间：
1980-01-01
影响因子：
3.1
通讯作者：
CHIEN, S
中科院分区：
文献类型：
--
作者：
LIPOWSKY, HH;USAMI, S;CHIEN, S
通过在体光密度测量，测定了猫肠系膜微血管连续分裂过程中微血管红细胞压积（Hmicro）的动静脉（A-V）分布。在小口径玻璃管中光密度和管血细胞比容的体外相关性允许计算20-70 μ m范围的管腔直径的Hmicro的体内值。对于较小尺寸的血管，通过微闭塞和红细胞计数确定Hmicro。结果表明，Hmicro/Hsystemic的比率从70 μ m小动脉中的0.80单调下降到紧邻毛细血管后（直径10 μ m）中的最小值0.21，随后单调上升到70 μ m小静脉中的0.95。在应用先前建立的体外放电和试管血细胞比容之间的关系后，部分证明了整个肠系膜网络中红细胞流量的守恒，所产生的差异归因于血液的流变学行为和红细胞的可能A-V分流。在全身性血液稀释过程中同时测量未分支小动脉中的压降和红细胞速度有助于比较体内和体外（锥板粘度计）表观粘度（η）。在不存在白细胞-内皮细胞粘附的情况下，对于24-47 μ m范围内的小动脉直径，没有发现两种方法之间的显著差异，其中0 < Hmicro < 36%，并且体内壁剪切速率高于500/s。η的原位测量在一个示例性的情况下，由于持续的流量减少期间白细胞粘附，发现增加了74%。η的值从Hmicro的A-V分布和η的回归计算出。vs. Hmicro（在没有白细胞粘附的情况下建立），与先前测量的η的A-V分布相比。存在白细胞粘附，表明白细胞粘附可能导致η的总体增加。范围从100到200%，遍及肠系膜网络。
The arteriovenous (A-V) distribution of microvessel hematocrit (Hmicro) was determined throughout successive microvascular divisions in cat mesentery from in vivo measurements of optical density. In vitro correlations of optical density and tube hematocrit in small-bore glass tubes permitted the computation of in vivo values of Hmicro for luminal diameters ranging from 20-70 .mu.m. For smaller-size vessels, Hmicro was determined by microocclusion and red cell counting. The results demonstrate a monotonic fall in the ratio of Hmicro/Hsystemic from 0.80 in the 70-.mu.m arterioles to a minimum of 0.21 in the immediate postcapillaries (10 .mu.m diameter) followed by a subsequent monotonic rise to 0.95 in the 70-.mu.m venules. Conservation of red cell flux throughout the mesenteric network was partially demonstrated upon applying previously established in vitro relationships between discharge and tube hematocrits, the resulting disparity being attributed to the rheological behavior of blood and possible A-V shunting of red cells. Simultaneous measurements of pressure drop and red cell velocity in unbranched arterioles during systemic hemodilution facilitated a comparison of in vivo and in vitro (cone-plate viscometer) apparent viscosities (.eta.). No significant differences between the 2 approaches were found for arteriole diameters ranging from 24-47 .mu.m in the absence of leukocyte-endothelium adhesion, with 0 < Hmicro < 36% and in vivo wall shear rates above 500/s. In situ measurements of .eta. were found to increase 74% due to leukocyte adhesion during sustained flow reductions, in one illustrative case. Values of .eta. computed from the A-V distribution of Hmicro and the regression of .eta. vs. Hmicro (established without leukocyte adhesion), in comparison with previous measurements of the A-V distribution of .eta. with leukocyte adhesion present, suggest that leukocyte adhesion may result in overall increases in .eta. ranging from 100 to 200%, throughout the mesenteric network.