Abstract
In studies concerning the cause of the reduction in blood pressure following carbon arc irradiation, it was of interest to obtain an estimate of the extent and degree of changes in capillary permeability produced by the irradiation. For this purpose Menken's trypan blue test 1 was used on rabbits.
The animals were divided into 2 groups of 10 each. Group I served as normal controls; Group II were irradiated over the abdominal area. The abdomen of all the rabbits was shaved at approximately the same time. One hour later Group II was exposed to the carbon arc lamp for 30 to 40 minutes at a distance of one meter. Four hours later all animals received intravenously 8 to 10 cc of 1% solution of trypan blue in normal saline. Two hours after injecting the dye the animals were carefully examined over the irradiated area of the abdomen, then killed, and the viscera compared with reference to the degree of staining by the dye.
The results showed striking differences. The skin and abdominal viscera of control animals presented a blue tinged appearance with the exception of the liver which appeared normal in color. The irradiated animals showed an extreme blue coloration of the skin and viscera many times more marked than that of the controls. The livers of these animals also showed coloration in contrast to the normally appearing livers of Group I. There was usually a collection of blue stained fluid (about 5 cc) in the abdominal cavity. Photographs in color were taken of a typical series to provide a permanent and objective record of the differences.
It would seem that irradiation of the rabbit with the dosage used in these experiments produces changes in the vascular system of the skin and abdominal organs which allow an increased amount of injected dye to escape from the blood stream and infiltrate the tissues.
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