Malyapa RS et al. · 1997
Researchers exposed mouse C3H 10T1/2 fibroblasts and human glioblastoma U87MG cells to FMCW (835.62 MHz) and CDMA (847.74 MHz) radiation at 0.6 W/kg SAR for up to 24 hours. They used the alkaline comet assay to measure DNA damage. No significant differences were found between exposed cells and sham controls.
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.
Maes A, Collier M, Van Gorp U, Vandoninck S, Verschaeve L · 1997
Researchers exposed cells to 935.2 MHz microwaves alone and in combination with mitomycin C and found no direct cytogenetic effect. Combined exposure to microwaves followed by mitomycin C produced a very weak effect compared to mitomycin C alone.
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.
French PW, Donnellan M, McKenzie DR, · 1997
Researchers exposed a human astrocytoma cell line, U-87 MG, to 835 MHz electromagnetic radiation for 20 min, 3 times per day for 7 days, at power densities of either 40 ± 15 mW cm−2 or 8.1 ± 3 mW cm−2. At the lower power density, the rate of DNA synthesis decreased and the cells flattened and spread out compared to unexposed cultures. At 40 mW cm−2 there were no effects on cell proliferation, but changes in cell shape included increased spreading and the appearance of actin-containing blebs on the membrane.
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.
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.
Lai H, Carino MA, Singh NP · 1997
Researchers exposed rats to 2450 MHz pulsed radiofrequency radiation at a power density of 2 mW/cm2 for 2 hours and then measured DNA double strand breaks in brain cells. The RFR exposure significantly increased DNA double strand breaks in rat brain cells, and the effect was partially blocked by naltrexone treatment. The researchers concluded that endogenous opioids play a mediating role in RFR-induced DNA strand breaks in brain cells of the rat.
Unknown authors · 1996
Researchers transfected HeLa cells with plasmids containing c-fos upstream regulating regions up to -700 base pairs linked to a CAT reporter gene. The cells were exposed to a 60 Hz electromagnetic field at 60 mGrms. CAT expression increased above control levels after 5 minutes of exposure, peaked at 20 minutes, and returned to basal levels after 40 minutes. Deletion analysis identified a responsive region of 138 base pairs from -363 to -225 containing SRE/AP-1 sites.
Unknown authors · 1996
Researchers exposed human melanoma MeWo cells to a 50-Hz, 400-mT extremely low frequency magnetic field and measured mutations in the hypoxanthine-guanine phosphoribosyl transferase gene. The mutant frequency increased with longer exposure periods and higher induced current intensities. Mutations induced by X-rays were enhanced by the magnetic field exposure. No significant increase in mutant frequency occurred when DNA replication was inhibited during exposure.
Unknown authors · 1996
The study examined the effects of extremely low frequency magnetic fields on cell growth and c-myc mRNA expression in Chinese hamster ovary cells. The study tested a 5 mT, 60 Hz magnetic field. The exposure system consisted of a CO2 incubator with built-in Helmholtz coils (250 mm inner diameter, 160 mm distance, 128 turns), a slide regulator, and a thermocontroller. No significant difference was found in growth rate or c-myc expression between cells exposed to the magnetic field, sham-exposed cells, and cells in a conventional incubator.
Unknown authors · 1996
Researchers treated cultured mammalian cells with three carcinogens that produce DNA single-strand breaks. The repair rate of these lesions was unchanged by 50 Hz electric, magnetic, or combined fields across a range of intensities.
Unknown authors · 1996
The study investigated the combined effects of 954 MHz microwaves and the DNA damaging agent mitomycin C. Whole blood samples were exposed in vitro to a 954 MHz emitting antenna from a GSM base station. Lymphocytes were then cultivated in the presence of mitomycin C. A highly reproducible synergistic effect was observed in sister chromatid exchange frequencies in metaphase figures.
Maes A, Collier M, Slaets D, Verschaeve L. · 1996
Researchers exposed whole blood samples to a 954 MHz GSM base station antenna and then cultured lymphocytes with mitomycin C. They measured sister chromatid exchange frequencies in metaphase figures.
Balode, Z · 1996
Researchers examined micronuclei in bovine peripheral erythrocytes from female Latvian Brown cows near the Skrunda Radar and from a control area. They counted micronuclei in 2000 erythrocytes per animal at 1000x magnification using a simplified Schiff DNA staining method. The exposed group had an average of 0.6 micronuclei per 1000 erythrocytes versus 0.1 per 1000 in controls, a statistically significant difference (P < 0.01).
Belyaev IY, Shcheglov VS, Alipov YD, Polunin VA · 1996
Researchers studied how millimeter waves affected the genome conformational state of E. coli AB1157 cells across a frequency range of 51.64 to 51.85 GHz. The resonance frequency of 51.755 GHz did not shift with power density, though the magnitude of the effect differed significantly and depended on the power density of exposure. Sharp narrowing of the 51.755 GHz resonance at lower power densities was followed by an emergence of new resonance frequencies.
Lai H, Singh NP · 1996
Researchers investigated single- and double-strand DNA breaks in rat brain cells after acute exposure to radiofrequency electromagnetic radiation. Rats received acute 2-hour exposure to pulsed or continuous-wave 2450-MHz radiofrequency electromagnetic radiation, producing a whole-body average-specific absorption rate of 1.2 W/kg. An increase in both types of DNA strand breaks was observed after exposure to either the pulsed or continuous-wave radiation, with no significant difference between the two forms.
Unknown authors · 1995
Researchers exposed human lymphoid cells immortalized by Epstein-Barr virus and HL60 leukemic cells to 50 Hz magnetic fields at 10 μT or 1 mT for periods ranging from 20 minutes to 72 hours. C-myc transcript levels were measured by Northern blot analysis normalized to the GaPDH gene. No statistically significant difference in c-myc transcript levels was observed between exposed and control cells for either cell type at any exposure duration, and the same result was found in cells synchronized in G0/G1 phase.
Unknown authors · 1995
Researchers performed an extensive series of experiments with human HL60 and Daudi cells incorporating blind exposures and internal standards. Exposure conditions covered flux densities from 5.7 microT to 10 mT and durations from 20 to 60 minutes. No alteration in the human MYC gene (c-myc) or beta-actin steady-state mRNA levels was observed.
Unknown authors · 1995
The study used quantitative Northern analysis to measure MYC and beta-actin mRNA levels in human leukemic HL60 cells. Cells were exposed to 60 Hz sinusoidal magnetic fields at 0.57, 5.7, or 57 microT for 20 minutes using a new field-exposure system designed to optimize any response. No significant effect of the electromagnetic fields on gene expression was observed with any of the exposure systems or analytical methods.
Kakita Y et al. · 1995
Researchers studied the effect of microwave irradiation on the survival of bacteriophage PL-1 specific for Lactobacillus casei using a commercial 2,450 MHz microwave oven. Phage inactivation followed almost first-order reaction kinetics and was unaffected by continuous versus intermittent irradiation or phage concentration but was affected by suspension volume which prevented heat loss. Phage genome DNA breakage was primarily caused by heat generated by microwave irradiation, while the same temperature from external heat did not affect phage DNA.
Belokhvostov AS et al. · 1995
The study aimed to investigate DNA analysis of retroposon-like genetic LINE elements in blood plasma of rats exposed to radio-diapason electromagnetic waves. The elevation of LINE-elements' DNA level was revealed in blood plasma of rats exposed to electromagnetic waves. The amount of full-size 5'-containing LINE-elements copies was increased especially. The researchers supposed a connection of this effect with retrotransposon activation and genetic instability condition of organism development.
Semin IuA, Shvartsburg LK, Dubovik BV · 1995
Researchers studied the effect of weak radiofrequency radiation on DNA secondary structure stability in vitro. Exposure at 3 or 4 Hz and 0.6 mW/cm2 peak power significantly increased accumulated DNA damage, while other pulse rates or power levels eliminated the effect. DNA was incubated with glycine and formaldehyde, and damage was assessed via thermal denaturation dynamics.
Cao G, Liu LM, Cleary SF · 1995
Researchers exposed synchronized Chinese hamster ovary (CHO) cells to 27 MHz continuous-wave radio-frequency radiation for 2 hours at specific absorption rates of 5 or 25 W kg−1 under isothermal conditions, meaning no heating occurred. The exposure produced time- and dose-rate-dependent cell cycle alterations, with maximum responses occurring 3 days after exposure at a SAR of 25 W kg−1. Cells in G0/G1- or S-phase showed more pronounced alterations, while G2/M-phase cells showed minimal effects at either SAR.
Lai H, Singh NP · 1995
Researchers measured DNA single-strand breaks in brain cells of rats acutely exposed to low-intensity 2450 MHz microwaves, using an alkaline microgel electrophoresis method. After 2 hours of exposure to pulsed microwaves, no significant effect was observed immediately after exposure, but a dose rate-dependent increase in DNA single-strand breaks was found in brain cells at 4 hours postexposure. In rats exposed for 2 hours to continuous-wave 2450 MHz microwaves at 1.2 W/kg SAR, increases in brain cell DNA single-strand breaks were observed both immediately and at 4 hours postexposure.
