Effects of Microwave Irradiation on Human Blood Platelets

The response of human blood platelets to microwaves (40 mW/cm2, 2.45 GHz, continuous 2-h exposure in a waveguide) was determined by measurement of several parameters related to platelet function. The microwave irradiated specimens were compared to control specimens heated over the same time-temperature course to a final temperature of 400C. The results related to platelet lysis (lactic dehydrogenase release) and to increased membrane permeability (potassium loss) indicated no significant effect of heating by either microwave or conventional methods. The results related to the platelet release reaction (14C-serotonin release) indicated that both microwave and conventional heating stimulated the release reaction in equal amounts. The results related to aggegation (apparent particle count) and to platelet function (response to added adenosine 5'-diphosphate) showed significant platelet modification, and significant differences between the irradiated and heated control specimens. However, the aggegation and functional impairment is less in the irradiated specimens than in the specimens heated by the conventional method. These results are consistent with a hypothesis that the observed effects are entirely thermal because platelets are highly temperature sensitive, and temperature gradients in conventional heating are higher than in microwave heating.