Bond J H, Levitt M D
Am J Physiol. 1979 May;236(5):E577-83. doi: 10.1152/ajpendo.1979.236.5.E577.
The accuracy of using 7- to 10-micron microspheres to measure blood flow to dog small intestinal villi was studied. These spheres appear to pass unimpeded through the afferent arterioles of the villus and lodge at the villus tip because 1) virtually all villus spheres were located at the tip, 2) flow determined by visually counting spheres did not differ significantly from flow determined from radioactivity of the sheared-off villus layer, 3) the size distribution of spheres in the villus and subvillus layers was virtually identical to that administered, indicating no premature impaction of the larger spheres, and 4) spheres lodging in the submucosa during vasoconstriction did not subsequently migrate to the villi during vasodilatation. Studies with 25-micron spheres indicated that 28% of the 7- to 10-micron spheres shunted through vessels greater than 10 micron. Double isotope studies showed that lodges spheres do not migrate and that the injection of 2--4 X 10(6) spheres does not alter villus flow. Thus, 7- to 10-micron microspheres pass to and lodge in villus vessels in proportion to capillary flow and should provide an accurate estimate of villus nutrient blood flow.
研究了使用7至10微米微球测量犬小肠绒毛血流的准确性。这些微球似乎能畅通无阻地通过绒毛的传入小动脉，并滞留在绒毛顶端，原因如下：1）几乎所有绒毛微球都位于顶端；2）通过目视计数微球确定的血流量与从剪下的绒毛层放射性确定的血流量没有显著差异；3）绒毛和绒毛下层微球的大小分布与所给予的微球大小分布几乎相同，表明较大微球不会过早滞留；4）血管收缩时滞留在黏膜下层的微球在血管舒张时不会随后迁移到绒毛。对25微米微球的研究表明，7至10微米微球中有28%通过直径大于10微米的血管分流。双同位素研究表明，滞留的微球不会迁移，注入2 - 4×10⁶个微球不会改变绒毛血流。因此，7至10微米微球按毛细血管血流比例进入并滞留在绒毛血管中，应该能准确估计绒毛营养血流。
