A teratological study of the rat: Microwave and infrared radiations compared

Abstract

Primigravid rats were exposed for 20 min to microwave radiation (2450 MHz; trueD˙=31±3mW/g ) in a multimode cavity or to infrared radiation in an incubator ( truet¯ ∼ 47 °C). They were exposed during one of seven days of gestation, the 10th through 16th. The Δ trueT¯ of the dams' colonic temperature, about 3.5 °C, was equated in the microwave and infrared treatments. Control groups of primigravid dams were sham radiated. During the 19th day of gestation, fetuses were taken by Caesarian section and were examined for structural abnormalities and for insult. In addition, fetal brains were analyzed for levels of dopamine (DA) and norepinephrine (NE). Findings: (1) the incidence of lethal dosing was 27% and 12%, respectively, in microwave‐ and infrared‐irradiated dams; (2) the averaged numbers of fetal resorptions in infrared‐ and sham‐irradiated dams are low (both ∼2%) but the number is elevated nearly sixfold in microwave irradiated dams; (3) the incidence of mortality in nonresorbed fetuses was nil; (4) extensive hemorrhagic signs were observed in both microwave‐ and infrared‐irradiated fetuses but there was no discernible evidence of structural malformation; (5) averaged fetal mass is slightly (10%) but reliably smaller in both irradiated groups as compared with controls; and (6) averaged whole‐brain DA levels do not differ reliably as a function of treatment but the averaged level of NE in brains of microwave irradiated fetuses is reliably below those of infrared and sham‐radiated fetuses. While the averaged ΔTs of the two groups of irradiated dams are equal, increments of temperature of microwave irradiated dams were more variable; correlative analysis provided evidence that mortality and resorption are probably a function of peak body temperature irrespective of source of radiation.

Microwave Radiation Enhances Teratogenic Effect of Cytosine Arabinoside in Mice

“…In contrast to exposures in nonthermal MW fields, a high number of resorptions after irradiation in MW fields at thermal power densities is one of the most common results published by many authors [2,4,9,13,26], The resorptions and malformations are believed to result exclusively from ther mal load, as lowering of the incidence of resorptions evoked by MW hyperthermia was found in mice anesthetized during expo sure (Nembutal) [26], probably because anes thesia reduced body temperature to the de gree equivalent to the rise in temperature expected from radiation dose.…”

“…There is no doubt that whole-body intrauterine MW hy perthermia applied during pregnancy may lead to resorptions or malformations of fe tuses, intrafetal hemorrhages, increased fetal mortality and/or inhibition of fetal growth [7,9,10,21,24,25]. However, many controver sies arise around the possible disorders caused by low-level exposure (not resulting in detectable thermal effects) to MW fields [2,7,17,18,26,29].…”

Radiofrequency fields and teratogenesis

“…The largest numbers of abnormalities occurred for exposure on days 13 and 14 and correlated well with rectal temperature increases. Chernovetz et al [1977] exposed pregnant rats for 20 min on only 1 day during gestation days 10-17 to 2.45 GHz RFEMF at 31 W/kg mean SAR. Other rats were either sham exposed or exposed to infrared radiation (IR) to obtain the 3.5 8C colonic temperature rise seen for RFEMF exposure.…”

Microwave Radiation and Thermoregulation.

“…An elevated deep body temperature has often been recorded in experimental animals exposed to microwaves, particularly if the absorbed energy is high (e.g., Michaelson et al, 1961;Chernovetz et al, 1977;Phillips et al, 1975;Michaelson, 1974;de Lorge, 1976). Prior to the start of the present project, certain compensatory thermoregulatory adjustments had been measured, including thermal adaptation (Michaelson et al, 1961), reduced metabolic heat production (Phillips et al, 1975;Ho and Edwards, 1977), and microwave avoidance (Frey et al, 1975).…”