Effects of 2.45 GHz microwaves on meiotic chromosomes of male CBA/CAY mice.

Male CBA/CAY mice were exposed daily (6 days a week) for 30 minutes in an environmentally controlled waveguide to continuous 2.45 GHz microwave radiation for 2 weeks at average whole body absorbed dose rates of 0.05, 0.5, 10, and 20 mW/g. Shan exposed animals served as controls. Chain translocations were observed at diakinesis at metaphase I in microwave exposed animals. The yield of translocations increased with exposure, and varied nonlinearly with dose rate. An increase in incidence of univalents was seen after exposure at 10 and 20 mW/g. The findings are interpreted to indicate interference with normal spermatogenesis during the exposure period.

Possible humoral mechanism of 2450-MHz microwave-induced increase in complement receptor positive cells.

These studies indicate that the increase in the frequency of complement receptor-positive (CR+) spleen cells observed 6 days after a 30-min exposure to 2450-MHz microwaves is not the result of microwave-induced alterations of lymphocyte recirculation patterns, but is mediated by a soluble, humoral factor produced by cells within the spleen.

Effect of microwaves (2450-MHz) on the immune system in mice: studies of nucleic acid and protein synthesis.

CBA/J adult male mice were given single or triple exposures to 2450-mHz microwaves in an environmentally controlled wave guide facility. The average absorbed dose rate for a single exposure varied from 12 to 15 mW/g. Sham-exposed mice served as controls. Lymphoid cells were collected and tested for metabolic activity on days 3, 6, and 9 following a single exposure, and on days 9, 12, and 16 following triple exposures on days 0, 3, and 6. Cells were cultured in vitro for four hours to seven days before their metabolic rates were assayed. Under these conditions, microwaves failed to produce any detectable change in deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein synthesis, as measured by the incorporation of methyl(3H)-thymidine (3H-TDR) (DNA substrate), 3H-uridine (3H-UR) (RNA substrate), and 3H-leucine (protein substrate) by spleen, bone marrow, and peripheral blood lymphocytes (PBL) in vitro. These data suggest that microwave-induced increases in the frequency of complement-receptor (CR)- or surface-immunoglobulin (sIg)-bearing cells were not associated with a concomitant increase in cell proliferation and/or protein synthesis, and favor the concept that microwaves under these conditions stimulate already existing B-cell precursors for maturation.

Biologic effects of microwave exposure. II. Studies on the mechanisms controlling susceptibility to microwave-induced increases in complement receptor-positive spleen cells.

In attempting to evaluate the mechanisms responsible for susceptibility to the inductive increase in splenic complement receptor-positive (CR+) cells following exposure to 2450-MHz microwaves, it was found that sensitivity to microwave-induced CR+ cell increases was under genetic control. In particular, evidence was accumulated suggesting that regulation was under the control of a gene or genes closely associated with but outside of the mouse major histocompatibility complex (H-2). All responsive strains of mice tested were of the H-2k haplotype, while mice of the H-2a, H-2b, H-2d and H-1i5 haplotypes were refractory to the microwave-induced increases in CR+ cells. By utilizing certain H-2k strains of mice that were genetically unable to respond to endotoxin, we were able to show that these strains of mice responded to microwaves, but not to endotoxin, by increasing CR+ cells. Microwave-induced increases in CR+ cells were not mimicked by the intraperitoneal injection of hydrocortisone. Athymic mice responded to microwave exposure, indicating that this event was not regulated by the T-cell population. Mice less than eight weeks old were found not to be susceptible to exposure to 2450-MHz microwaves. These studies indicate that microwaves do induce changes in the population of cells with specific cell-surface receptors, that susceptibility to these changes is under genetic control, and that it is unlikely that endotoxin, corticosteroids, or regulatory T cells play a significant role in the mechanisms regulating these increases.

Increase in the frequency of Fc receptor (FcR) bearing cells in the mouse spleen following a single exposure of mice to 2450 MHz microwaves.

A single 30-min exposure (13,7 +/- 1.2 mW/g) of mice to 2450 MHz microwaves produced a significant increase in the proportion of FcR+ cells in the spleen. This increase was due to a selective increase in FcR+ B cells. No changes in total B (Ig+) and T (theta+) cell frequency in the spleen were observed.

Microwaves induce an increase in the frequency of complement receptor-bearing lymphoid spleen cells in mice.

A single 30-min exposure of mice to 2450 MHz microwaves (12 to 15 mW/g body weight) in an environmentally controlled waveguide facility induced a significant increase in the proportion of complement-receptor positive lymphoid cells in the spleen. This effect was further enhanced by repeated (three times) exposures, which in addition produced a significant increase in the proportion of Ig+ cells. The proportion of theta-positive cells and the total number of spleen cells remained unchanged.