Millimeter waves at 25 mW/cm2 have no effect on hydroxyl radical-dependent lipid peroxidation

The effect of millimeter waves on (OH)-O-.-dependent lipid peroxidation was studied. Liposomes treated with (OH)-O-.-generating systems such as ferrous sulfate plus hydrogen peroxide and EDTA-Fe3+ plus ascorbic acid showed a marked increase in the amount of lipid peroxides. When these systems were exposed to continuous millimeter waves of 53.6 GHz frequency and incident power density of 25 mW/cm(2), no difference in the formation of lipid peroxides was observed between irradiated and unirradiated samples. Preirradiation of liposomes with millimeter waves at this frequency and intensity followed by (OH)-O-.-dependent lipid peroxidation did not exhibit any difference in the concentration of lipid peroxides between preirradiated and unirradiated samples. The present results indicate that reported beneficial effects of millimeter waves in reducing the toxic effect of chemotherapy do not result from the direct inhibition of (OH)-O-.-dependent lipid peroxidation.