Figure 1: Histogram of calculated diameters of vascular vessels. Horizontal line: diameters of lumens, blue bars: CD31-expressing vessels, and red bars: artery/arteriole and vein/venule. The difference in the number of vessels detected either with hematoxylin/eosin staining or with CD31 staining was more in vessels whose diameters were less than 100 μm compared with larger vessels.