COLLAPSE OF K-CELLS, ERYTHROCYTES AND STAPHYLOCOCCUS-AUREUS( AND IONIC BALANCE DURING PHOTODYNAMIC INACTIVATION OF LEUKEMIC)

1. The immediate and fast ionic fluxes in Friend erythroleukemic cells (FELC), erythrocytes and Staphylococcus aureus during short intervals of porphyrin mediated photosensitization were determined uniquely by X-ray microanalysis (XRMA) combined with electron microscopy. 2. Photo dynamic inactivation of FELC was mediated by either endogenous protopo rphyrin induced by 5-amino levulinic acid (5-ALA), or Photofrin-II. We describe the predominant phenomena of > 85% K-loss within 2-1 0 min o f photoactivation. However the accompanied Na inflow and the collapse of the cellular balance of elemental-composition were inconsistent and acted as a function of cell damage. 3. Erythrocytes treated with hema toporphyrin (HP) lost most of their intracellular K yet instantly gain ed Na. Nevertheless the K/Na molar ratio of the control erythrocytes w as nearly 12/1 while after photosensitization and K loss it changed to 1/1. 4. The S. aureus bacteria photosensitized with HP showed entire K-loss as well as marked Na efflux which increased with irradiation ti me; this was accompanied by the decline of other cell elements. 5. The prevailing K loss in FELC, erythrocytes and bacteria during the first minutes of photosensitization is deduced to be an immediate primary c onsequence of the photodynamic effect, while other ionic changes are j oined in order with the development of cellular damage.