Brown HD, Chattopadhyay SK · 1991
Researchers studied how 9.14 GHz continuous-wave microwave radiation affected ouabain inhibition of Na+/K+-ATPase from dog kidney. Exposure for 5 minutes to 9.14 GHz radiation at an estimated SAR of 20 W/kg was applied at several stabilized temperatures between 7.0 and 43.8 °C. The efficacy of ouabain as an inhibitor of ATPase activity was severely diminished by the microwave field, and at 24.9 °C a 23% decrease in activity occurred.
Koveshnikova IV, Antipenko EN · 1991
Researchers studied whether thyroid hormones play a role in modifying the mutagenic effect of microwaves in rats. The mutagenic effect of microwaves at 2,450 or 2,750 MHz, 500 microW/cm2, for 30 days at 7 hours a day increased when rats had either low or high thyroid hormone levels. The researchers concluded that normal thyroid gland functioning appears to be an important condition for maintaining chromosome integrity under microwave exposure.
Spiers DE, Baummer SC · 1991
Researchers exposed Japanese quail eggs to 2,450 MHz microwaves at 5 or 20 mW/cm² for 8 hours daily from day 1 to 15 of incubation. At 30 °C ambient temperature, microwave exposure increased wet-embryo mass on day 16 by 9% at 5 mW/cm² and 61% at 20 mW/cm² compared to predicted masses without microwaves. Post-treatment tests showed no reliable indication that repeated microwave exposure resulted in abnormal physiological development. The authors concluded that microwave radiation can increase egg temperature and embryonic growth rate at below-normal incubation temperatures without altering basic metabolic and thermal characteristics.
Garaj-Vrhovac V, Horvat D, Koren Z · 1991
Balcer-Kubiczek EK, Harrison GH. · 1991
Researchers exposed actively growing cultures of C3H/10T1/2 cells for 24 hours to 2.45-GHz microwaves pulse-modulated at 120 Hz. The electromagnetic fields alone had no effect on cell survival or induction of neoplastic transformation. When combined with the tumor promoter TPA, the enhancement of transformation was highly significant and ranged up to a level equivalent to that produced by 1.5 Gy of X rays. The frequency of neoplastic transformation was dependent on the level of electromagnetic exposure and was additive with doses of X rays given as a cocarcinogen.
Koveshnikov IV, Antipenko EN · 1991
Garaj-Vrhovac V, Horvat D, Koren Z, · 1990
Researchers exposed Chinese hamster cells to microwave radiation at 7.7 GHz (similar to radar frequencies) for up to one hour and found significant DNA damage. The radiation completely blocked cells from entering their normal DNA replication phase and caused chromosome abnormalities that persisted even after exposure ended. This demonstrates that microwave radiation can directly interfere with genetic processes at the cellular level.
Neubauer C, Phelan AM, Kues H, Lange DG · 1990
Researchers exposed male albino rats to 2.45-GHz microwaves with 10-microseconds pulses at 100 pps. Exposure at 10 mW/cm2 for 30 to 120 minutes increased tracer uptake through the blood-brain barrier. The uptake depended on both power density and exposure duration. At 5 mW/cm2, a 15-minute exposure had no effect. Pretreating rats with colchicine nearly completely blocked the microwave-induced uptake.
Kerbacher JJ, Meltz ML, Erwin DN, · 1990
Cleary SF, Liu LM, Merchant RE · 1990
Researchers exposed whole human blood in vitro for 2 hours to 27 or 2,450 MHz radio-frequency electromagnetic radiation under isothermal conditions at 37 degrees C. At SARs below 50 W/kg, exposure produced a dose-dependent, statistically significant increase in lymphocyte proliferation, while exposure at 50 W/kg or higher suppressed proliferation relative to sham-exposed cells. The researchers concluded that these biphasic, dose-dependent effects on lymphocyte proliferation were not dependent on heating. There were no detectable effects of RF radiation on lymphocyte morphology or viability.
Ray S, Behari J · 1990
Researchers studied the effects of exposure to sublethal levels of microwaves. Young albino rats of both sexes were exposed for 60 days to 7.5-GHz microwaves at 0.6 mW/cm2 for 3 hours daily. The exposed animals tended to eat and drink less and showed a smaller gain in body weight. Some hematological parameters and organ weights were significantly different in exposed rats. The authors proposed that a nonspecific stress response mediated through the central nervous system caused the changes.
Meltz ML, Eagan P, Erwin DN · 1990
Researchers studied forward mutation at the thymidine kinase locus in L5178Y mouse leukemic cells exposed to 2.45-GHz pulsed-wave RFR and proflavin. Exposures used 500 or 600 W net forward power, giving a SAR of approximately 40 W/kg, for 4 hours with temperature controls. No statistically significant increase in mutant frequency was found with combined RFR and proflavin versus proflavin alone, no change in colony-size distribution occurred, and RFR alone showed no mutagenic action.
Garaj-Vrhovac V, Horvat D, Koren Z · 1990
Researchers exposed cultured V79 Chinese hamster cells to continuous microwave radiation at 7.7 GHz and a power density of 30 mW/cm2 for 15, 30, and 60 minutes. The study measured the incorporation of [3H]thymidine into DNA and the frequency of chromosome aberrations. Inhibition of [3H]thymidine incorporation occurred through complete prevention of DNA from entering into the S phase, and the normal rate of incorporation recovered within one generation cycle of V79 cells. Compared with control samples, irradiated cells showed a higher frequency of specific chromosome lesions.
T.T. · 1990
Researchers reviewed biological effects of static magnetic fields and found no specific target organ for deleterious effects at present. A documented effect is the induction of electrical potentials in major arteries during exposure, with 60 mT producing a 1 mV potential in the human aorta. Pacemaker reed switches can close at 1.7 mT, so wearers should be excluded from fields exceeding 1.0 mT.
Unknown authors · 1989
Researchers conducted a population-based case-control study of leukemia and residential proximity to electricity supply equipment in south-east England. The study included 771 leukemia cases matched to 1,432 cancer controls and 231 general population controls. Exposure to power-frequency magnetic fields was assessed indirectly from the distance, type, and loading of nearby power lines and transformer substations. Only 0.6% of subjects lived within 100 m of an overhead power line, where the relative risk of leukemia was 1.45 (95% CI 0.54-3.88), rising to 2.0 within 50 m (95% CI 0.4-9.0). Over 40% of subjects lived within 100 m of a substation, with a relative risk of 0.99, and residence within 25 m carried a risk of 1.3 (95% CI 0.8-2.0).
Unknown authors · 1989
Unknown authors · 1989
Researchers exposed rats to low-level pulsed microwave radiation at 2.45 GHz (the same frequency as microwave ovens) and found significant changes in brain chemistry, including alterations to the cholinergic system that controls memory and learning. The study revealed that even brief 20-minute exposures affected brain receptor concentrations in key regions like the hippocampus and frontal cortex.
Unknown authors · 1989
University of Washington researchers exposed rats to pulsed 2.45 GHz microwaves (the same frequency as microwave ovens) and found significant changes to brain chemistry systems involved in memory and learning. The study showed that even low-level microwave exposure altered choline uptake and muscarinic receptors in brain regions critical for cognitive function. These neurochemical changes occurred at power levels well below current safety standards.
Unknown authors · 1989
Indira Nair, M. Granger Morgan, H. Keith Florig · 1989
Unknown authors · 1988
Researchers studied 356 children diagnosed with cancer between 1976 and 1983 in the Denver area and compared them with controls selected by random digit dialing. Measured magnetic fields under low power use at a 2.0 milligauss cutoff showed an odds ratio of 1.4 for total cancers, with higher odds ratios for leukemias, lymphomas, and soft tissue sarcomas. Wire configuration codes contrasting very high and high versus very low, low, and buried codes yielded an odds ratio of 1.5 for total cancers. Adjusted estimates for measured fields and wire codes did not differ from crude results, indicating an absence of confounding.
Parker JE, Kiel JL, Winters WD · 1988
Researchers exposed four rodent cell lines to 2450 MHz microwave radiation at a Specific Absorption Rate of 103.5 +/- 4.2 W/kg at temperatures of 37, 40, 42, and 45 degrees C. The researchers extracted mRNA from exposed and sham-exposed cells and used DNA probes of oncogenes, heat shock protein, or long terminal repeat sequences to look for differences in mRNA expression. With the cell lines and probes used, no significant differences in mRNA expression were observed after microwave exposure.
D'Andrea JA, DeWitt JR, Portuguez LM, Gandhi OP. · 1988
Two experiments tested whether frequency-specific hotspot formation in the body and tail of rats would have behavioral consequences. Rats were placed in a cage where occupying one side triggered microwave exposure and occupying the other side ended it. Reduced exposure to 360-MHz and 2450-MHz microwaves at 1, 2, 6 and 10 W/kg were significantly different from 700-MHz microwaves. A second experiment found the threshold for reduced exposure to 2450-MHz microwaves fell between whole-body SARs of 2.1 and 2.8 W/kg.
Unknown authors · 1988
Nine men were exposed to 4.1 GHz radio-frequency radiation in an accident. Two men were exposed to 4.6 mW/cm2 for up to 90 minutes, exceeding the Australian standard of 1 mW/cm2, while seven others received lower exposures. Comprehensive medical examinations, including follow-up ophthalmological exams over nine months, were performed on all staff. Various abnormalities were found in all staff, but there was no consistent gradient of effect between exposure groups except possibly for hair loss. The investigators concluded that the exposure had not resulted in harmful effects.
Unknown authors · 1987
Researchers exposed chick embryos to sinusoidally oscillating 50 Hz magnetic fields during their first two days of development. In the first series, abnormal embryo percentages were 16% in controls, 16% at 0.1 A/m, 14% at 0.3 A/m, 29% at 1 A/m, and 32% at 10 A/m. In the second series, abnormal embryo percentages were 17% in controls, 10% at 0.4 A/m, 19% at 0.6 A/m, 17% at 0.9 A/m, and 36% at 1.35 A/m. Only the 1.35 A/m group was significantly different from controls in the second series. The results suggest that exposure causes abnormal development and that no abnormalities are induced below a threshold between 0.9 and 1 A/m.
