PORPHYRIN-INDUCED ENHANCEMENT OF ULTRASOUND CYTOTOXICITY

We examined the effect of ultrasound on the murine leukaemia L1210 cel l line in culture, in the presence of porphyrins varying widely in the ir capacity to sensitize cells to light. These porphyrins enhanced ult rasound-induced cell damage in vitro only when present in the incubati on medium. When cells containing intracellular porphyrins were exposed to ultrasound, cell viability was not altered. Moreover, there was no correlation between the efficacy of a given porphyrin for light- vers us ultrasound-induced cytotoxicity. Loss of viability was associated w ith inhibition of amino acid transport and cell fragmentation, suggest ing disruption of the integrity of the cell membrane. Ultrasound-induc ed cell damage occurred only in the presence of cavitation nuclei.