ID Number		913
Study Type		In Vitro
Model		245, 9.4, 17, 70 GHz (CW) exposure to cultured cells, bacteria, and yeast and analysis of growth
Details		Chinese hamster V-79 cells were exposed to 2450 MHz (CW) at SARs of 62, 76, and 87 W/kg until culture temperature reached 45 C, then immediately diluted and subcultured for colony-forming and trypan exclusion assays. Parallel studies were performed with non-MW conventional heating in a water bath. Survival decreased more with MW exposure as a function of temperature than with waterbath heating, especially at the higher SARs. The authors explain this by suggesting that microwave treated cells absorbed more thermal energy and experienced more rapid temperature rise times than waterbath-heated cells. In a similar study, V-79 cells were exposed as above at SARs of 10-100 W/kg and compared with non-MW heated controls. Exposure did not affect viability or mitochondrial activity, but did result in slight differences in viscosity and membrane permeability that the authors attributed to membrane alterations due to differences in the pattern of heating. In related studies, yeast were exposed to 9.4, 17, or 70 GHz (CW) MW at SARs between 20-25 W/kg to produce a temperature elevation of ~ 4 degrees C. Although exposure did not result in any effects on survival or mutation frequency, at equal power densities exposure to 17 GHz resulted in more zygote formation than 9.4 GHz exposure. At higher temperature elevations, using either MW or non-MW heating, decreased survival, impaired function, and structural damage was observed. In other studies, radiation sensitive strains of E. coli and S. cerevisiae were exposed to 70-75 GHz or 9.4 GHz for 30 minutes or 17 GHz (CW) MW for up to 20 hours at SARs between 10-30 W/kg. Exposure did not result in any increased mutation frequency. Non-MW heat treatments, however, did decrease survival and increase mutation rates. Finally, an early study exposed Drosophila melanogaster eggs, larvae, and pupae to 17 and 73 GHz (CW) MW for 2-3 hours did not result in any effects on viability or teratogenesis. A slight but statistically significant decrease in tumor incidence was observed in adult flies following exposure, regardless of what growth stage was exposed to MW, although similar tumor decreases were also observed in certain adult flies with non-MW heating.
Findings		Effects (only at thermal levels)
Status		Completed With Publication
Principal Investigator		Institut Curie, France
Funding Agency		Private/Instit.
Country		FRANCE
References		Dardalhon, M et al. Int J Radiat Biol, (1985) 48:987-996 Dardalhon, M et al. Bioelectromagnetics, (1984) 5:247-261 Dardalhon, M et al. Radiat. Environ. Biophys., (1981) 20:37-51 Dardalhon, M et al. J. Microwave Power, (1979) 14:307-312
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