Measurement of Plasma Volume in the Dog With High Concentrations of T-1824

Abstract

Twelve out of 16 paired successive estimates of plasma volume, 1 hr. apart, show that the volume distribution of T-1824 is independent of the quantity injected up to plasma concns. of 1.3 mg./ml. Extensive hemolysis occurred in 4 expts. where the plasma dye concn. exceeded 1.3 mg./ml. Plasma dye concns. were estimated with the paper pulp extraction procedure. The hemolytic effect of T-1824 occurs in vitro as well as in vivo. However, washed blood cells are 50% destroyed by only 0.02 mg./ml., which corresponds to the free dye in plasma when the total dye is 3 mg./ml. The human red cell is extremely resistant and either in plasma or saline is not affected by 4 mg./ml. The species difference suggests that the red cell membranes contain differing proteins. Toxic effects of the dye in dogs appear to be related to the occurrence of hemolysis.