PRE-IRRADIATED PHOTOOXIDIZED PSORALEN INDUCES HEMOLYSIS AND CHANGES IN ELECTRICAL PARAMETERS OF ERYTHROCYTE-MEMBRANES

The effects of pre-irradiated photo-oxidized psoralen (POP) on human e rythrocytes (RBCs) were investigated. Psoralen in ethanol solutions wa s photo-oxidized and then added to a suspension of erythrocytes. The h emolysis and the electric impedance of the suspension were measured in the frequency range 5-20 MHz. The membrane capacity C(M), and the ext racellular and intracellular conductivitieS kappa(a) and kappa(1) were calculated from these data. There appeared to be a threshold concentr ation of POP for hemolysis. When the concentration of POP slightly exc eeded this threshold, the hemolytic effect rapidly increased to a maxi mum, but a further increase in POP concentration slowed down the rate of hemolysis. POP induced a decrease in extracellular conductivity and an increase in membrane capacity, but did not affect intracellular co nductivity. The changes in extracellular conductivity correlated well with hemolysis.