In this study we have examined the influence of intravenous Escherichia coli endotoxin on the induction of endothelial injury and repair in the aorta and pulmonary artery of the dog, with special reference to areas of Evans blue dye uptake. The sequential changes were monitored by quantitation of the numbers of circulating endothelial cells in three vascular beds, by incorporation of [3H] thymidine by endothelial cell nuclei, and by light microscopy of silver nitrate-stained Häutchen preparations.

Focal areas of spontaneous increased aortic endothelial permeability to the protein-binding azo dye Evans Blue in vivo have been further characterized in 8–12 week-old normocholesterolaemic pigs by means of Häutchen preparations with [3H]thymidine autoradiography, together with observations on endothelial cell length, cell area, and surface morphology.