EMF Research Studies

In vitro effects of low-level, low-frequency electromagnetic fields on DNA damage in human leucocytes by comet assay

Unknown authors · 1999

4G mobile phone radiation alters some immunogenic and vascular gene expressions, and gross and microscopic and biochemical parameters in the chick embryo model

Unknown authors · 1999

Exposure to mobile phone radiation may result in gross, microscopic, and biochemical changes. Such exposure may also alter gene expression in ways that could hinder embryonic development.

Frequency of micronuclei in the blood and bone marrow cells of mice exposed to ultra-wideband electromagnetic radiation.

Vijayalaxmi et al. · 1999

Peripheral blood and bone marrow smears were examined for micronuclei in polychromatic erythrocytes at 18 and 24 hours after exposure. No statistically significant differences were found in micronuclei frequency or percentage of polychromatic erythrocytes between exposed mice and controls.

Bacterial mutation in high magnetic fields and radiofrequency radiation

Mineta M et al. · 1999

Researchers exposed Salmonella typhimurium tester strains to a 6.3 Tesla magnetic field with RF radiation for up to 60 minutes. They used TA98 and TA7001-7006 mixed strains to detect frameshift and point mutations. The rates of revertant mutation were not statistically significant in either strain.

TP53 tumor suppressor protein in normal human fibroblasts does not respond to 837 MHz microwave exposure.

Li et al. · 1999

Researchers exposed human fibroblast cells to 837 MHz continuous microwaves for 2 hours at SAR levels of 0.9 or 9.0 W/kg. TP53 protein levels were measured by Western blot at 2, 8, 24, and 48 hours after exposure. No significant changes in TP53 protein expression were found in exposed cells compared to sham or untreated cells at any time point. No morphological alterations were observed in microwave-treated cells compared to sham-treated cells.

Proto-oncogene mRNA levels and activities of multiple transcription factors in C3H 10T 1/2 murine embryonic fibroblasts exposed to 835.62 and 847.74 MHz cellular phone communication frequency radiation.

Goswami PC et al. · 1999

Researchers exposed C3H 10T 1/2 mouse embryo fibroblasts to 835.62 MHz FMCW or 847.74 MHz CDMA microwaves at an average SAR of 0.6 W/kg and measured proto-oncogene expression. The exposures did not alter proto-oncogene expression kinetics after serum stimulation, nor did they change Jun and Myc mRNA levels or AP1, AP2, and NF-kappaB DNA-binding activity during the transition to plateau phase. However, 835.62 MHz FMCW exposure increased Fos mRNA about 2-fold in exponential and plateau-phase cells, and 847.74 MHz CDMA exposure increased it 1.4-fold.

Micronucleus assay and lymphocyte mitotic activity in risk assessment of occupational exposure to microwave radiation.

Garaj-Vrhovac, V · 1999

Researchers investigated micronucleus assay and lymphocyte mitotic activity in 12 workers occupationally exposed to microwave radiation. Exposed subjects showed increased micronuclei frequency and disturbances in the distribution of cells over the first, second and third mitotic division compared to controls.

MYC mRNA abundance is unchanged in subcultures of HL60 cells exposed to power-line frequency magnetic fields

Unknown authors · 1998

Researchers exposed HL60 cells to 6-microT 60 Hz magnetic fields and measured MYC expression. The assay methods and exposure conditions were as close as practical to those of the investigators that originally reported a positive effect. A chemical agent demonstrated the cells responded to a known stimulus and the system had low basal variability to detect effects of the previously reported magnitude. Using cells from a commercial source and from the original investigators, no evidence was found that EMF exposure induces MYC expression.

Suppression of high-density magnetic field (400 mT at 50 Hz)-induced mutations by wild-type p53 expression in human osteosarcoma cells

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.

BIGEL analysis of gene expression in HL60 cells exposed to X rays or 60 Hz magnetic fields

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.

Influences of 50-Hz magnetic fields and ionizing radiation on c-jun and c-fos oncoproteins

Unknown authors · 1998

Researchers exposed primary rat tracheal epithelial cells and two immortalized cell lines to a 50-Hz magnetic field at 100 microT[rms] combined with a 55 microT geomagnetic-like field and to gamma rays from cobalt-60. Both exposures produced similar patterns and amplitudes of c-jun and c-fos protein induction. Combining magnetic field and radiation exposure did not produce a synergistic effect on protein expression.

The genotoxic potential of electric and magnetic fields: an update

Unknown authors · 1998

The authors reviewed 23 studies published since their 1993 review of 55 studies plus six additional earlier studies. Three attempts to replicate previously reported positive results were unsuccessful. Negative studies in several exposure categories met the quality criteria.

Ultra-wide band electromagnetic radiation does not affect UV-induced recombination and mutagenesis in yeast.

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.

DNA damage in rat brain cells after in vivo exposure to 2450 MHz electromagnetic radiation and various methods of euthanasia.

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.

Microwave irradiation influences on the state of human cell nuclei.

Shckorbatov YG et al. · 1998

Researchers studied changes in electrokinetic properties and heterochromatin granules in human buccal epithelium cell nuclei under electromagnetic fields in vitro. Cells were irradiated using a semiconductor generator at 42.2 GHz (7.1 mm wavelength) with a Yav-1 apparatus. Irradiation decreased nuclear electric charge and increased chromatin condensation, with effects varying by dose and donor.

Cytogenetic changes induced by low-intensity microwaves in the species Triticum aestivum

Pavel A, Ungureanu CE, Bara II, Gassner P, Creanga DE · 1998

Researchers exposed wheat seeds with uniform genetic background to a microwave flow at 9.75 GHz and low intensity at various doses. Compared to controls, exposed seeds showed chromosomal aberrations including delayed chromosomes, micronuclei, interchromosomal bridges, and chromosomal fragments. The effects of microwaves at various doses on mitotic activity were also followed.

Transgenic nematodes as biomonitors of microwave-induced stress.

Daniells et al. · 1998

Researchers used transgenic Caenorhabditis elegans strain PC72 carrying a heat-shock promoter driving a beta-galactosidase reporter gene. The nematodes were exposed in a transverse electromagnetic cell at 750 MHz and 27 dBm, with the cell held at 25°C in a shielded incubator. Significant stress responses were observed at 2 and 16 hours but not at 4 or 8 hours. Lower power levels of 21 dBm produced greater responses than 27 dBm at both 750 and 300 MHz, a pattern opposite to that expected from simple heating. In a 5 x 5 multiwell plate, wells in rows nearest the exposure showed the strongest response, while the most distant row did not rise above control levels, suggesting a shadow effect.

DNA damage in Molt-4 T- lymphoblastoid cells exposed to cellular telephone radiofrequency fields in vitro

Phillips et al. · 1998

Researchers exposed Molt-4 T-lymphoblastoid cells in vitro to pulsed radiofrequency signals at cellular telephone frequencies of 813.5625 MHz (iDEN® signal) and 836.55 MHz (TDMA signal) to detect DNA damage. The alkaline comet assay was used to measure DNA single-strand breaks in exposed cell cultures compared to sham-exposed cultures. At an SAR of 24 μW g−1, exposure to the iDEN® signal for 2 h and 21 h significantly increased DNA damage, while at 2.4 μW g−1 the same signal significantly decreased DNA damage. The researchers concluded that the data indicate a need to study the effects of exposure to RF signals on direct DNA damage and on the rate at which DNA damage is repaired.

Acute exposure to a 60 Hz magnetic field increases DNA strand breaks in rat brain cells

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.

The effect of 50 Hz electromagnetic fields on the formation of micronuclei in rodent cell lines exposed to gamma radiation

Unknown authors · 1997

Frequency of micronuclei in the peripheral blood and bone marrow of cancer-prone mice chronically exposed to 2450 MHz radiofrequency radiation.

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.

Proliferation and cytogenetic studies in human blood lymphocytes exposed in vitro to 2450 MHz radiofrequency radiation.

Vijayalaxmi, Mohan, N, Meltz, ML, Wittler, MA, · 1997

DNA synthesis and cell proliferation in C6 glioma and primary glial cells exposed to a 836.55 MHz modulated radiofrequency field.

Stagg RB, Thomas WJ, Jones RA, Adey WR · 1997

Researchers exposed transformed and normal rat glial cells to an 836.55 MHz packet-modulated RF field at power densities of 0.09, 0.9, and 9 mW/cm2, with SARs from 0.15 to 59 muW/g. Primary rat glial cells showed no significant differences in DNA synthesis between sham and RF-exposed conditions for either log-phase or serum-starved cultures. C6 glioma cells exposed at 5.9 muW/g SAR showed small but significant increases in thymidine incorporation in 38% of experiments. Growth curves showed no differences between sham and RF-exposed cultures for either cell type, and doubling times of C6 glioma cells did not differ significantly.

Exposure of nerve growth factor-treated PC12 rat pheochromocytoma cells to a modulated radiofrequency field at 836.55 MHz: effects on c-jun and c-fos expression.

Ivaschuk OI et al. · 1997

Researchers exposed nerve growth factor-treated PC12 rat pheochromocytoma cells to a packet-modulated 836.55 MHz radiofrequency field at power densities of 0.09, 0.9, and 9 mW/cm2 for 20, 40, or 60 minutes, with an intermittent 20-minute on/off regimen. Sham-exposed cells served as controls, and c-fos and c-jun expression was measured by Northern blot analysis of total RNA. C-fos transcript levels did not change after 20 minutes at any intensity, while c-jun transcripts decreased by 38% only after 20 minutes at 9 mW/cm2.

Effects of high-frequency electromagnetic fields on human lymphocytes in vitro.

Antonopoulos A, Eisenbrandt H, Obe G, · 1997

Human peripheral lymphocytes were incubated in the presence of high-frequency electromagnetic fields of 380, 900 and 1800 MHz. The measured endpoints were cell cycle progression and the frequencies of sister-chromatid exchanges. No differences between treated and control cultures could be found.