Donald I. McRee

SOME EFFECTS OF EXPOSURE OF THE JAPANESE QUAIL EMBRYO TO 2.45‐GHz MICROWAVE RADIATION

Exposure of quail eggs 4 hr per day during the first 5 incubation days at 2450 MHz and in an exposure field of 30 mW/cm-2 and at an absorbed power of 14 mW/g does not cause any great change in body weight, observed gross malformations, rbc, wbc, hematocrit, hemoglobin, or differential wbc percentages. If small differences exist in these parameters due to microwave exposure, they are obscured by the large variability between individual quail. This variability is believed to partially result from changing blood values in the developing young quail, and the 2-day spread in ages at the time of sacrifice could account for some of the variability. The overall hatch percentages for the exposed and control eggs were approximately equal. A slight significant decrease (11%) in hemoglobin was noted in the birds irradiated on Day 2. Additional verification, however, is needed, because the observed change is less than the normal range of values observed in young quail. These data do suggest, however, that exposure of developing Japanese quail embryo to microwave radiation of the frequency and power density level used in this study does not preclude normal systemic development, hematologic differentiation, or the general hardiness of the hatched quail.

Pulse microwave effects on nerve vitality

Isolated sciatic nerves of frogs were exposed to 2.45-GHz pulse-microwave radiation in a waveguide exposure system at an average specific absorption rate (SAR) of 10 mW/g. In previous studies using continuous-wave (cw) microwave radiation at an SAR of 10 mW/g, survival time of the irradiated nerve when stimulated to fire at a high rate (50 twin pulses per sec) was shorteded significantly. This investigation was performed to determine if pulse-microwave radiation produced the same of different effects on the vitality of frog sciatic nerves as continuous-wave microwave radiation. Three sets of experiments were carried out using 10-..mu..sec-wide pulses at 50 pps, with an average SAR of 10 mW/g: (1) asynchronous pulsing wherein the mw pulse was delivered at varying times in the firing cycle; (2) synchronous pulsing during the peak of the nerve action potential; and (3) synchronous pulsing during the quiescent period between nerve firings. In all three cases a significant decrease in the survival time of the exposed nerves, as compared to their unexposed mates, was seen. However, the magnitude of this effect was essentially the same in all three cases and was also comparable with the ffect seen earlier using cw (of equivalent SAR).

Exposure of Japanese quail embryos to 2.45-GHz microwave radiation during development.

Japanese quail embryos were exposed during the first 12 days of development to 2.45 GHz microwave radiation at an incident power density of 5 mW/cm/sup 2/ and specific absorption rate of 4.03 mW/g. No gross deformities were observed in the exposed quail when examined and sacrificed at 24 to 36 hr after hatch. No significant changes in the total body weight or weights of the heart, liver, gizzard, adrenals, and pancreas were found in the treated birds. Hematological parameters were also measured in the study. The results showed a statistically significant increase in hemoglobin and statistically significant decrease in monocytes in birds treated with microwave radiation. No statistically significant changes in hematocrits, red blood cells, total white blood cells, lymphocytes, heterophils, basophils, or eosinophils were detected.

Teratogenic, biochemical, and histological studies with mice prenatally exposed to 2.45-GHz microwave radiation.

Pregnant CD-1 mice were exposed to 2.45-GHz continuous wave microwave radiation at an incident power density of 30 mW/cm2. The local specific absorption rate near the uterine area (deep colonic location), as determined from time-temperature profiles measured with a Vitek thermistor probe, was 40.2 mW/g. Groups of mice were exposed 8 hr per day through Days 1-6 or 6-15 of pregnancy. Other groups of animals were exposed to an elevated ambient temperature of 31 degrees C which increased the colonic temperature 2.3 degrees C, the same as that produced by the microwaves. Sham-irradiated groups of animals were treated exactly the same as the microwave-exposed animals. For the two conditions, temperature exposed and sham exposed, two groups of animals were used. One group was handled in the same manner as the microwave-irradiated group and the other group was not handled so as to evaluate the effects of stressing the animals by handling. Eleven groups of animals were used in the complete study: five groups for gestational Days 1-6, five groups for gestational Days 6-15, and one group of cage control animals. On Day 18 of gestation the dams of all experimental groups were sacrificed and their reproductive status was determined. The fetuses were examined for visceral and skeletal alterations. Brain cholinesterase activity and histology were evaluated in the groups exposed on Days 6-15. The results show that microwave radiation increases embryo lethality at the early stages of gestation (exposure Days 1-6). Fetal toxicity and teratogenicity were not significantly increased by exposure to microwaves on either Days 1-6 or 6-15 of gestation. Cholinesterase activity and histology of the brain of 18-day-old fetuses were not adversely affected.

Exposure of the Japanese Quail Embryo to 2.45 GHz Microwave Radiation During the Second Day of Development

ABSTRACTThe Japanese quail, (Coturnix coturnix japonica), embryo was exposed to 2.45 GHz continuous wave microwave radiation through the intact shell. The eggs were exposed continuously for 24 hours beginning 24 hours after the start of incubation at an exposure intensity of 30 mW/cm2. The quail were examined after hatching for gross deformities, changes in organ weight and hematological changes. No highly significant effects due to microwave radiation were detected.

Incidence of Sister Chromatid Exchange in Bone Marrow Cells of the Mouse Following Microwave Exposure

The measurement of sister chromatid exchange (SCE) constitutes the most sensitive indicator yet developed for detecting cytogenetic effects of mutagens and carcinogens. This sensitive assay was utilized to investigate potential mutagenic bioeffects of microwave (2450-MHz) radiation by comparing the incidence of SCE in bone marrow cells of sham control mice, standard control mice, and irradiated rice following a 28-day exposure to 20 mW/cm/sup 2/ incident power density. No statistically significant differences in the numbers of SCEs were detected between the exposed group and the control groups.

Microwave Radiation Effects on Cardiac Muscle Cells in Vitro

Isolated cardiac muscle cells were exposed to microwave radiation in a temperature-controlled waveguide apparatus. Microwave radiation for 90 min at specific absorption rates (SAR) as low as 10 mW/g increases the permeability of cardiac cells to trypan blue. At 100 mW/g the inability of the cells to exclude trypan blue is concurrent with the release of lactic dehydrogenase into the suspending medium. However, when the SAR is decreased to 50 mW/g, trypan blue uptake is still elevated without the concomitant release of lactic dehydrogenase. Transmission electron micrographs of the exposed cells showed cellular damage only at the 100 mW/g exposure level. The microwave-reduced change in membrane permeability was unrelated to a macroscopic heating effect of microwave radiation on the cells, but appeared to be due to some other specific action of microwave radiation on isolated cardiac cells.

Reproduction in Male Japanese Quail Exposed to Microwave Radiation during Embryogeny

Japanese quail (Coturnix coturnix japonica) embryos were exposed continuously to 2.45 GHz CW microwave radiation during the first 12 days of embryogenesis. The incident power density was 5 mW/cm2, and the specific absorption rate (SAR) was 4.03 mW/g. At 23 weeks of age an assessment of the reproductive capacity of the males was performed. Spermatozoal numbers and motility in semen samples which were collected manually were reduced significantly (P less than or equal to 0.01). However, spermatozoal viability and gross morphological characteristics in the exposed birds were not consistently different from the controls. Relative testicular weights were not altered significantly in the exposed males. Percentage of fertile eggs was significantly reduced when exposed males were mated to sham control females. The percentage of fertile eggs obtained from mating exposed males with sham control females was 72.5%, while the percentage of fertile eggs from mating of sham control males with sham control females was 80.4%. These data indicate that reproductive capacity in male Japanese quail is reduced when the birds are exposed to 2.45 GHz CW microwave radiation during embryogenesis.

Humoral immunity of Japanese quail subjected to microwave radiation during embryogeny.

Fertile Japanese quail eggs were exposed to continuous wave microwave radiation at an intensity of 5 mW/cm2 (50 W/m2) and a frequency of 2450 MHz. The absorbed power density was determined to be 4.03 W/kg. The eggs were exposed throughout the first 12 days of the normal incubation period of 17.5 days. Non-exposed control eggs were incubated in a chamber identical to the exposure chamber. After hatching, exposed and control quail were reared in the conventional laboratory manner. Weekly body weight measurements were made to compare the growth patterns of exposed and control quail. The weights of the exposed male at the ages of 4 and 5 weeks were 12 and I % , respectively, less than the control males. These differences approached statistical significance ( P ~ 0 . 0 5 ) . At 5 weeks of age the quail were challenged with sheep red blood cells (SRBC) and the levels of the anti-SRBC antibodies were determined. The levels of specific anti-SRBC antibodies, determined 4 days after antigen challenges, were of the same magnitude for both the exposed and control quail. Following this assessment of humoral immunity, the quail were sacrificed and the bursa of Fabricius and spleen were removed and a comparison was made of exposed and control birds. The weights of the bursa of Fabricius and spleen were not altered significantly by the microwave exposure. Research Triangle Park, NC27709 PAUL THAXTON and CARMEN R. PARKHURST

A circular dichroism study of human erythrocyte ghost proteins during exposure to 2450 MHz microwave radiation

The effect of 2450 MHz microwave radiation on the proteins of human erythrocyte ghosts has been investigated using circular dichroism spectroscopy. A specially constructed waveguide inserted into the spectropolarimeter allowed the continuous recording of optical activity before, during and after microwave irradiation. The data indicate that high levels of microwave radiation (600 mW/g, specific absorption rate) induce decreases in α-helical conformation that may result from both thermal vibrations and increased strain on the intramolecular hydrogen bonds that maintain secondary structure. The latter effect may result from differential intramolecular interactions with the oscillating electric field. Spectrin (bands 1 and 2) isolated from the ghosts was more sensitive to microwave irradiation than intact ghosts, and spectrin-depleted vesicles were the least sensitive. The data, therefore, indicate that the α-helical conformation of spectrin is altered by high levels of microwave radiation.