Microwave and Temperature Effects on the Murine Ocular Lens In Vitro.
Annual summary rept. 1 Sep 79-30 May 80,
UNIVERSITY OF WESTERN ONTARIO LONDON DEPT OF BIOCHEMISTRY
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Rat ocular lenses were studied after fixation and critical point drying of the tissue by scanning electron microscopy SEM following exposures to elevated temperatures andor microwave irradiation in a thermostatically controlled chamber. In this way, the temperature of the lens bathing medium was set independently of the temperature increases normally associated with application of microwave power. Irradiations were done at three final temperatures and three specific absorption rates SAR for two durations. These were accomplished at 915 MHz in WR975 waveguide with either pulsed Pu or continuous wave CW9 radiation of equal average power. The parameters of the Pu radiation were selected to maximize the production of thermoacoustic expansion. The results are summarized as follows 1 Exposure of lenses in vitro to elevated temperatures for 1 hour followed by a 2-day incubation in tissue culture medium 199 M199 produced predominantly subcapsular and epithelial defects at 39 C, while at 41 C, extensive globular degeneration was added. 2 Microwave pulsed irradiation in vitro at 37 C followed by a 2-day incubation in M199 produced globular bodies and subcapsular foam at the lowest SAR 120 mWg and shortest duration 5 min. At the intermediate SAR 400 mWg and 5 minute duration, holes in the lens fibers were added. 3 Microwave irradiation at 39 C and 41 C followed by a 2-day incubation in M199 caused more damage at all SARs and durations than at 37 C. 4 Fixation of the lenses without incubation did not reveal any defect in the sham irradiated control at 39 C. 5 At a given temperature, increased duration appeared to substitute for lower SAR.