Michael J. Galvin

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.

Evaluation of In Vitro Effects of 50 and 60 Hz Magnetic Fields in Regional EMF Exposure Facilities

Abstract Boorman, G. A., Owen, R. D., Lotz, W. G. and Galvin, M. J., Jr. Evaluation of In Vitro Effects of 50 and 60 Hz Magnetic Fields in Regional EMF Exposure Facilities. A weak association between magnetic-field exposure and increased incidences of cancer has been reported. While alterations in cellular processes after in vitro magnetic-field exposures have also been reported to provide plausibility for this association, other laboratories have been unable to repeat the findings. As part of an accelerated electric- and magnetic-field (EMF) research program, the National Institute of Environmental Health Sciences with the Department of Energy identified the replication of the published positive effects as a priority. Regional EMF exposure facilities were established to investigate major in vitro effects from the literature. These included effects on gene expression, intracellular calcium, colony growth in soft agar, and ornithine decarboxylase activity. The laboratories that first reported these effects provided experimental protocols, cell lines, and other relevant experiment details. Regional facility studies included sham/sham exposures (no applied field in either chamber) and were done in a blinded fashion to minimize investigator bias. In nearly all experiments, no effects of magnetic-field exposure were found. The effort provided insight into dealing with the difficulty of replication of subtle effects in complex biological systems. Experimental techniques provided some clues for the differences in experimental results between the regional facility and the original investigator. Studies of subtle effects require extraordinary efforts to confirm that the effect can be attributed to the applied exposure.

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.

Studies on acute in vivo exposure of rats to 2450-MHz microwave radiation. 1. Mast cells and basophils

Eight-hour continuous exposure to 2450-MHz microwave radiation in rats was carried out at incident power densities that cause no apparent temperature increase (2 and 10 mW/cm/sup 2/). The peritoneal mast cells were unchanged in their viability, percentage, toluidine blue metachromasia, histamine content, or size. Isolated mast cells from control and irradiated rats responded in a similar manner to drugs that stimulate histamine secretion via both the chemical (compound 48/80, a condensation product of p-methoxy-N-methyl phenethylamine and formaldehyde) and immunological (concanavalin A) pathways. Rats subjected to both levels of irradiation were similar to the controls in their initial blood pressures and their hyposensitive response to 48/80.

Effect of 2450 MHz Microwave Radiation on Hematopoiesis of Pregnant Mice

In this study, the influence of 2450 MHz CW microwave radiation on hematopoiesis in pregnant mice was examined. Dams (mice CD-1 strain) were irradiated during Days 1-6 or 6-15 of pregnancy. The animals were irradiated for a total of 8 hr per day (two 4-hr exposures in 9 hr) at an average power density of 30 mW/cm2. Peripheral blood and bone marrow samples were obtained on Day 18 of pregnancy. The total leukocyte and differential leukocyte counts of peripheral blood samples were not affected by either exposure regimen. In addition, no effects were noted in either the erythroid or myeloid mitotic indices of bone marrow samples. Exposure of pregnant mice to microwave radiation under the conditions of these experiments had no effects on the investigated aspects of hematopoiesis.

An approach to NMR studies of the metabolism of internal organs using surface coils

This communication describes a surgical preparation of experimental animals to permit NMR spectroscopic studies of the metabolism of internal organs. In the procedure developed, the layer of protective muscle directly above the organ is removed, but the skin is left intact. NMR studies of the metabolism of the organ can then be carried out using surface coils placed externally over the herniated area. Modified probe and stack designs for use with the surgically modified animals in a conventional NMR spectrometer are described. Phosphorus-31 NMR spectra of liver and kidney of the modified animals have been obtained, and data corresponding to the hepatic response to a load of fructose are presented.

The effect of 2450-MHz microwave radiation during microtubular polymerization in vitro

Exposure to 2450-MHz (cw) microwave radiation causes inhibition of cell division in intact cells and varied in vivo biological effects in both avian and mammalian species. Because these reported effects may result from alterations in the dynamics of microtubule formation, we studied the effects of simultaneous microwave exposure (2450 MHz, cw) during each of the three critical stages of the intracellar polymerization cycle. In addition, using circular dichroism spectroscopy, we studied the effect of microwave irradiation on the secondary structure of purified tubulin polypeptides. These studies were accomplished using specially constructed exposure systems that permit the continuous recording of turbidometric or circular dichroism measurements during simultaneous exposure to microwaves. The baseline turbidity of microtubular protein did not change under the influence of microwave radiation (20 or 200 mW/g SAR) and irradiation had no effect on the light-scattering properties of the depolymerized protein. EGTA-induced polymerization and cold-induced depolymerization patterns were also similar for both control and microwave-irradiated samples. The circular dichroism spectrum of purified tubulin also did not appear to be influenced by microwave irradiation, indicating a lack of effect on the protein secondary structure. The data suggest that the cellular effects of microwaves are not due to changes in microtubular proteins or their rate of polymerization.

Studies on acute in vivo exposure of rats to 2450-MHz microwave radiation. III. Biochemical and hematologic effects.

Male rats were exposed to 2450-MHz cw microwave radiation for 8 hr at incident power densities of 0 (sham), 2, or 10 mW/cm/sup 2/. Following exposure, rats were killed by decapitation, and blood samples were collected for determination of hematocrit, hemoglobin, red and white cell count, and differential white cell percentages. The total red and white cell counts were not affected by either exposure level. The blood hemoglobin level was also unaffected by the 8-hr microwave exposure, having a value of approximately 15.5 g% for all three groups. The percentages of lymphocytes and neutrophils for both exposed groups was similar to those of the sham group. The other cell types were also unchanged by the microwave exposure. None of the serum biochemistries examined were affected by either microwave exposure level. These data therefore demonstrate that acute (8 hr) exposure to 2450-MHz cw microwave radiation has no effect on the hematologic and biochemical parameters examined.

Studies on Acute in Vivo Exposure of Rats to 2450-MHz Microwave Radiation: II. Effects on Thyroid and Adrenal Axes Hormones

The effects of 8 hr continuous exposure of rats to 2450-MHz (cw) microwave radiation were studied at incident power densities of 0, 2 and 10 mW/cm/sup 2/. Thyroid axis function, as measured by serum thyroxine (T/sub 4/) and triiodothyronine (T/sub 3/) as well as T/sub 3/ uptake, free thyroxine index, and adjusted-T/sub 4/ values was not altered by the experimental conditions. Adrenal axis activity was also unaffected in rats exposed to 2 mW/cm/sup 2/ microwave radiation for 8 hr. In the 10 mW/cm/sup 2/ group, the serum corticosterone levels were less than in the 0 or 2 mW/cm/sup 2/ groups (7.8 versus 9.9 ..mu..g/dl). The experimental protocol increased serum corticosterone levels (7.0 versus 9.9 ..mu..g/dl for the nonhandled and sham-exposed groups, respectively); however, the corticosterone concentration in the 10 mW/cm/sup 2/ group was similar to that in the untreated (nonhandled) controls (7.8 versus 7.0 ..mu..g/dl). This modified adrenal axis function gives further support to the concept that microwave radiation affects endocrine function.

Response of Japanese quail to hemorrhagic stress after exposure to microwave radiation during embryogeny.

Coturnix coturnix japonica eggs were exposed to 2.45 GHz continuous wave microwave radiation at an incident power density of 5 mW/cm2 (SAR = 4 mW/g) during the first 12 days of embryogeny. After hatching, hematologic changes in response to an acute hemorrhage were measured in exposed and nonexposed (control) juveniles and adults of both sexes. Reticulocyte numbers and percentages were depressed below control numbers at 24 hr postphlebotomy in exposed adult females. Lymphocyte numbers were depressed below control levels at 24 hr postphlebotomy in exposed juvenile and adult males. At 72 hr heterophil numbers were depressed in exposed juvenile and adult males. These data suggest that microwave irradiation during embryogeny affects the ability of Japanese quail to recover from an acute and voluminous hemorrhage and that these radiation effects are small.