Utley J R, Marshall W G, Boatman G B, Dickerson G, Ernst G B, Daughtery M E
Surgery. 1980 Feb;87(2):222-9.
Variations in the distribution of different size microspheres trapped within an organ depend upon regional variations in delivery or trapping of different size spheres. We have determined the intrarenal distribution of trapped 9 mu and 15 mu spheres, as well as their nontrapping and release in dog kidneys. More 15 mu spheres than 9 mu spheres are normally trapped in the outer cortex, and fewer 15 mu spheres than 9 mu spheres in the medulla. This is true whether the renal blood flow enters the organ through the hilum or through capsular collaterals with chronic renal artery occlusion. The differences in distribution are due to greater trapping of 15 mu spheres than 9 mu spheres in the outer cortex with subsequent greater delivery and trapping of 9 mu spheres than 15 mu spheres in the vasa rectae of the medulla. Axial migration of the larger 15m spheres with greater distribution to terminal branches of a vessel and less distribution to proximal branches does not explain these observations, because it is independent of the transcortical direction of blood flows. Studies with adenosine triphosphate (ATP) vasodilation show that 15 mu spheres are trapped to a greater degree than 9 mu spheres and that previously trapped 9 mu spheres may be released with ATP vasodilation. Nontrapping and release of microspheres are potential sources of error and are greater with 9 mu than 15 mu spheres.
器官内捕获的不同大小微球的分布变化取决于不同大小球体在递送或捕获方面的区域差异。我们已经确定了狗肾脏内捕获的9微米和15微米球体的肾内分布，以及它们在肾脏中的非捕获和释放情况。通常，外皮质中捕获的15微米球体比9微米球体多，而髓质中捕获的15微米球体比9微米球体少。无论肾血流是通过肾门进入器官还是通过慢性肾动脉闭塞时的包膜侧支进入器官，都是如此。分布上的差异是由于外皮质中15微米球体的捕获量比9微米球体大，随后髓质直小血管中9微米球体的递送和捕获量比15微米球体大。较大的15微米球体向血管末梢分支的分布更多，向近端分支的分布更少，这种轴向迁移并不能解释这些观察结果，因为它与血流的跨皮质方向无关。用三磷酸腺苷（ATP）血管舒张进行的研究表明，15微米球体的捕获程度比9微米球体更大，并且先前捕获的9微米球体可能会随着ATP血管舒张而释放。微球的非捕获和释放是潜在的误差来源，9微米球体比15微米球体的误差更大。
