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Small pieces of guinea-pig skin were exposed to a uniform field of microwaves at χ-band (8,730 MHz). Measurements showed that 26% of the incident energy was reflected, 34% was absorbed, and the remaining 40% was transmitted. Absorbed energy was converted to heat, causing a rise in the temperature of the skin. After exposure to microwaves the skin was maintained on a nutrient medium. Uptake of radioactive substances from the medium into skin constituents was measured. A graded reduction in the uptake of sulphate ions into chondroitin sulphate, proline into collagen, and of phosphate into phospholipid, nucleic acid, and phosphoprotein fractions was found. The incident energy density causing 50% reduction of all these biochemical activities was approximately 4,750 mJ./sq. cm. under the thermal conditions of the experiment. The cooling rate of the tissue is important in determining the effect of microwaves. [ABSTRACT FROM PUBLISHER]

An apparatus was designed which enabled small pieces of skin to be exposed to a uniform field of microwaves at χ-band (8,730 MHz). This was used to investigate the effect of these microwaves at selected energy levels on the metabolism of skin. It was shown that skin cultured exhibited a graded response to microwave energy, and a doseresponse curve was constructed from this data. The ED of this curve was 4,740 mW./sq. cm. applied for 1 second. Microscopical examination of three-day cultures of skin showed that histological abnormalities occurred if the specimens were exposed to intensities of microwaves causing more than 30% respiratory damage. The energy level at the ED was 2,880 mW./sq. cm. applied for 1 second. Results were consistent with the hypothesis that tissue damage caused by irradiation with microwaves was due to the energy absorbed by the specimen being converted to heat. [ABSTRACT FROM PUBLISHER]