Pakhomova ON, Belt ML, Mathur SP, Lee JC, Akyel Y · 1998
Researchers exposed yeast cells to UV radiation followed by ultra-wide band electromagnetic pulses. The UWB pulses had intensities of 101-104 kV/m, 1.0 ns width, 165 ps rise time, and repetition rates of 0 Hz (sham), 16 Hz, or 600 Hz. The effect was evaluated by colony-forming ability on complete and selective media and the number of aberrant colonies. The experiments found no effect of UWB exposure on UV-induced reciprocal and non-reciprocal recombination, mutagenesis, or cell survival.
Unknown authors · 1998
Researchers exposed cultured human osteosarcoma Saos-LP-12 cells to a 400 mT, 50 Hz extremely low frequency magnetic field. The exposure induced mutations in the HPRT gene. The Saos-LP-12 cells have a deletion in the p53 coding region. Introducing a wild-type p53 expression plasmid into these cells suppressed the ELFMF-induced mutations. No marked difference in the mutation spectrum was observed among ELFMF exposure with or without p53 and sham exposures.
Unknown authors · 1998
Researchers screened 1,920 randomly selected cDNAs in HL60 cells exposed to 60 Hz magnetic fields (2 mT) or X rays (5 Gy) compared to unexposed cells. Eighteen cDNAs were differentially expressed in X-irradiated cells, and 15 matched known genes related to cell growth, protein synthesis, energy metabolism, oxidative stress, or apoptosis. BIGEL analysis revealed no differences greater than 1.5-fold in expression levels in magnetic-field-exposed cells compared to sham-exposed cells.
Nakamura et al. · 1998
Researchers exposed pregnant rats to microwaves at 2 mW/cm2, 2450 MHz for 90 minutes and measured natural killer cell activity and beta-endorphin levels. Microwave exposure raised colonic temperature and increased beta-endorphin in blood and anterior pituitary but did not change corticosterone. Naloxone administered before exposure increased natural killer cell activity and beta-endorphin in blood and placenta of pregnant rats.
Kavaliers M, Choleris E, Prato FS, Ossenkopp K · 1998
Researchers studied how nitric oxide (NO) and nitric oxide synthase (NOS) influence opioid-induced antinociception in the land snail Cepaea nemoralis, and whether these chemicals play a role in the effects of extremely low frequency (ELF) magnetic field exposure. Pain relief was measured by how long snails took to withdraw their foot from a thermal stimulus of 40°C. Exposure to a 60-Hz magnetic field at 141 μT peak for 15 minutes reduced the enkephalinase-induced antinociception in the snails. The inhibitory effects of the magnetic field were significantly reduced by a nitric oxide synthase inhibitor and significantly enhanced by a nitric oxide releasing agent.
Braune, S, Wrocklage, C, Raczek, J, Gailus, T, Lucking, CH · 1998
The study enrolled seven healthy men and three women volunteers aged 26 to 36 years in a single-blind placebo-controlled design. Participants were exposed to a GSM 900 MHz signal at 2 Watt with a 217 Hz frame repetition rate for 35 min per session. Blood pressure and heart rate were recorded continuously with a Finapres device, while capillary perfusion was measured with an infrared plethysmograph on the right hand.
Kwee S, Raskmark P · 1998
Researchers exposed transformed human epithelial amnion cells to 960 MHz microwave fields at three power levels and three exposure times using a TEM cell. Cell growth was reduced in exposed cells compared to control and sham-exposed cells. The proliferation response varied with SAR level and exposure duration, showing a linear correlation between power level and growth change. At lower power levels, a longer exposure time was needed to reach the maximum effect, and repeated exposures did not alter the outcome.
Malyapa RS et al. · 1998
Researchers exposed male Sprague-Dawley rats to 2450 MHz continuous-wave microwaves for two hours at 1.2 W/kg specific absorption rate. No significant differences in DNA damage were found between sham-exposed and irradiated rats in either the cerebral cortex or hippocampus, regardless of euthanasia method. Rats euthanized by CO2 asphyxia showed more intrinsic DNA damage and greater experiment-to-experiment variation than those euthanized by guillotine. The authors concluded that guillotine euthanasia is the most appropriate method for DNA damage studies. The study did not confirm previous reports of DNA damage from 2450 MHz microwave exposure.
Mann et al. · 1998
Researchers exposed healthy humans to a 900 MHz pulsed electromagnetic field (217 Hz, 0.02 mW/cm²) and measured nocturnal hormone profiles of growth hormone, cortisol, luteinizing hormone, and melatonin under polysomnographic control. Cortisol showed a slight, transient elevation that persisted for one hour after exposure onset. No significant changes were found for growth hormone, luteinizing hormone, or melatonin, and sleep EEG showed no significant alterations, though there was a trend toward REM suppression.
Repacholi et al. · 1997
Researchers exposed female E mu-Pim1 transgenic mice to pulsed 900 MHz fields for two 30-minute periods per day for up to 18 months. Lymphoma risk was significantly higher in exposed mice than in controls (OR = 2.4, P = 0.006). Follicular lymphomas were the major contributor to the increased tumor incidence.
Lai, H, Singh, NP, · 1997
Researchers investigated the effects of microwave exposure on DNA strand breaks in rat brain cells. They found that treating rats with either melatonin or the spin-trap compound PBN immediately before and after radiofrequency electromagnetic radiation exposure blocked the DNA strand breaks. Because both substances are free radical scavengers, the researchers hypothesized that free radicals are involved in the radiofrequency electromagnetic radiation-induced DNA damage.
Unknown authors · 1997
Rats were exposed for 2 h to a 60 Hz magnetic field at flux densities of 0.1, 0.25, and 0.5 mT. DNA strand breaks in brain cells were assayed by microgel electrophoresis 4 h postexposure. Single-strand DNA breaks increased after exposure to 0.1, 0.25, and 0.5 mT, while double-strand DNA breaks increased at 0.25 and 0.5 mT.
Unknown authors · 1997
Unknown authors · 1997
They note that EMF energies are far below those typical of biomolecules, induced electric forces are considerably smaller than biological forces, and magnetic-moment sensory cells have not been found in humans. Resonant interaction mechanisms conflict with accepted physics and many experimental tests have not found the predicted effects. The review states that biological effects at residential levels [< or = 2 microT (< or = 20 mG)] are implausible, while effects at higher fields [> 10 microT (> 100 mG)] might reach plausibility but lack demonstrated transduction structures.
Persson BRR, Salford LG, Brun A · 1997
Researchers studied blood-brain barrier permeability in Fischer 344 rats of both sexes exposed to radio frequency electromagnetic fields. The exposure used 915 MHz microwaves delivered as either pulse-modulated or continuous wave signals. The rate of pathological leakage rose from 0.17 in controls to 0.39 across all exposed rats, a highly significant difference. Continuous wave exposure produced a higher rate of pathological rats (0.50 ± 0.07) than pulse-modulated exposure (0.35 ± 0.03), and that difference was also statistically significant.
Lai H, Singh NP · 1997
Researchers investigated whether melatonin and the spin-trap compound N-tert-butyl-alpha-phenylnitrone (PBN) could block the effect of magnetic fields on brain cell DNA. Rats were injected with melatonin or PBN immediately before and after two hours of exposure to a 60-Hz magnetic field at an intensity of 0.5 mT. Both drug treatments blocked the magnetic field-induced DNA single- and double-strand breaks in brain cells, as measured by a microgel electrophoresis method.
Roschke, J, Mann, K · 1997
Researchers tested 34 healthy men in a single-blind cross-over study with a 900 MHz GSM field at 0.05 mW/cm² for nearly 3.5 minutes. They measured spontaneous EEG from C3 and C4 under closed eyes and found no difference in spectral power density between active and inactive phone conditions.
Malyapa RS et al. · 1997
Researchers used the alkaline comet assay to test whether 2450 MHz radiation causes DNA damage in cultured mammalian cells. Exponentially growing U87MG and C3H 10T1/2 cells were exposed to 2450 MHz CW radiation at SARs of 0.7 and 1.9 W/kg for durations of 2 h, 2 h followed by 4-h incubation, 4 h, and 24 h. No significant differences were observed between the test group and the controls after exposure.
Vijayalaxmi et al. · 1997
C3H/HeJ mice prone to mammary tumors were exposed to 2450 MHz RF radiation at 1.0 W/kg for 20 hours per day, 7 days a week, over 18 months, with sham-exposed controls and positive controls treated with mitomycin C. The incidence of micronuclei in peripheral blood and bone marrow did not differ significantly between RF-exposed and sham-exposed groups. Positive controls treated with mitomycin C showed significantly elevated micronuclei frequencies. A separate analysis of mice that developed mammary tumors also found no significant differences in micronuclei frequency between exposure groups.
Unknown authors · 1997
Researchers conducted a case-control study in northern Taiwan matching on date of birth, sex, and date of diagnosis to evaluate risks of adult leukemia, brain tumors, and female breast cancers in relation to residential exposure to 60-Hertz magnetic fields. The analysis included 870 leukemia cases, 577 brain tumor cases, and 1,980 female breast cancer cases. For leukemia, exposure to magnetic fields above 0.2 microtesla versus below 0.1 microtesla yielded an odds ratio of 1.4 (95% CI = 1.0-1.9), and living within 50 meters versus 100 meters or more from transmission lines gave a relative risk of 2.0 (95% CI = 1.4-2.9).
Litovitz et al. · 1997
Researchers exposed L929 cells to 60 Hz AM microwave fields or a 50 Hz burst-modulated DAMPS digital cellular phone field together with 30-100 Hz ELF noise up to 10 microT for 8 h. ODC enhancement decreased exponentially with increasing noise amplitude, with complete inhibition at 2 microT or higher for 60 Hz AM microwaves and 5 microT or higher for the DAMPS signal.
Unknown authors · 1997
Researchers used data from 12,063 Finnish twins who completed a depression inventory in 1990. Exposure was assessed using 20-year histories of distance to and calculated magnetic fields from 110- to 400-kV overhead power lines. Adjusted mean depression scores did not differ by exposure level. The risk of severe depression was 4.7 times higher for those living within 100 meters of a high-voltage line, though this was based on small numbers.
Gos, P, Eicher, B, Kohli, J, Heyer, WD · 1997
Researchers exposed exponentially growing Saccharomyces cerevisiae cells to electromagnetic fields from 41.682 GHz to 41.710 GHz in 2 MHz increments at power densities of 0.5 and 50 microW/cm2. Cell division was assessed by time-lapse photography using two identical chambers that allowed concurrent control and exposure experiments. Control experiments showed the cells were dividing at submaximal rates, ensuring that any increase or decrease in division rate could be observed. No consistently significant differences were found between exposed and unexposed cells across multiple independent experiment series.
Cleary, SF, Cao, G, Liu, LM, Egle, PM, Shelton, KR · 1997
Researchers investigated stress protein induction in HeLa and CHO cells following a 2-hour exposure to radiofrequency or microwave radiation. Cells were exposed under isothermal conditions maintained at 37 ± 0.2 °C. Neither microwave nor RF radiation had a detectable effect on stress protein induction.
Fiorani M et al. · 1997
Researchers investigated the effects of 50 Hz magnetic fields (0.2–0.5 mT) on rabbit red blood cells exposed at the same time to an oxygen radical-generating system, Fe(II)/ascorbate. A 0.5 mT magnetic field had no effect on intact red blood cells, but when cells were already under oxidative stress, exposure caused a significant further decay in hexokinase activity of about 20% and a twofold increase in methemoglobin production. The researchers concluded that the magnetic fields studied were able to potentiate the cellular damage induced in vitro by oxidizing agents.
