Vascular pattern in the chorioallantoic membrane (CAM) after laser/photosensitive compound treatment. I. Macroscopic findings.

Laser light and photosensitive compound meso-tetra(4- sulfonatophenyl)porphine dodecahydrate tetra-sodium salt (TPPS4) activated by laser light were used for examining a regressive vascular effect with focal morphological differentiation of chick chorioallantoic membrane (CAM). After laser/TPPS4 treatment, arrest of blood flow in the irradiated area of CAM was observed in all cases, followed by massive aggregation of erythrocytes obstructing the vessel lumina. Similar effects were observed under much prolonged laser radiation in the area vasculosa. No extravasates were found. Those findings support the concept that the biological effect of low power laser/TPPS4 treatment causes changes in the relationship between red cells, blood plasma and embryonal endothelium during angiogenetic processes in growing embryonal vessels.