GENERATION OF ACTIVE OXYGENS, CELL-DEFORMATION AND MEMBRANE-POTENTIALCHANGES UPON UV-B IRRADIATION IN HUMAN BLOOD-CELLS

The generation of peroxides (presumably hydrogen peroxide) by UV-B irr adiation of human blood cells was detected. Non-fluorescent dihydrorho damine 123 (DHR) is oxidized to fluorescent rhodamine 123 (R123) by H2 O2 or peroxides with a stoichiometry of 1:1 in the presence of exogene ous peroxidase, and the fluorescence of R123 within the cells was meas ured using flow-cytometry. UV irradiation gave rise to changes in the cellular volume and the membrane potential, whose extent and direction were dependent on the type of blood cells. The production of peroxide s (H2O2) in polymorphonuclear leukocytes is the largest among blood ce lls at the lower dose (< 0.1 J/cm(2)), and the production decreases wi th an increase in the dose, while the production in platelets is the s mallest at the lower dose, but above 0.4 J/cm(2) it increases suddentl y so that at the higher dose (1.2 J/cm(2)) it amounts to 3.3 x 10(-16) mol/cell. For monocytes and lymphocytes, the production increases gra dually with the increase in the dose.