DNA & Genetic Damage

A preliminary study to assess possible chromosomal damage among users of digital mobile phones.

Gadhia PK, Shah T, Mistry A, Pithawala M, Tamakuwala D. · 2003

[Effects of low-intensity extremely high frequency electromagnetic radiation on chromatin structure of lymphoid cells in vivo and in vitro]

Gapeev AB et al. · 2003

Researchers exposed NMRI mice to extremely high-frequency electromagnetic radiation at 42.0 GHz and 0.15 mW/cm2 for 20 minutes and examined chromatin structure in immune cells using a comet assay technique. Three hours after exposure, fluorescence intensity increased by 16% in thymocytes and decreased by 16% in splenocytes, while peripheral blood leukocytes showed no change. In vitro exposure reduced fluorescence intensity by 23% in Raji human lymphoid line cells and by 18% in peripheral blood leukocytes.

Exposure of human peripheral blood lymphocytes to electromagnetic fields associated with cellular phones leads to chromosomal instability.

Mashevich M et al. · 2003

Researchers examined whether in vitro exposure of human peripheral blood lymphocytes to continuous 830 MHz electromagnetic fields causes losses and gains of chromosomes, a condition called aneuploidy. Cells were irradiated at SAR levels ranging from 1.6 to 8.8 W/kg for 72 hours. A linear increase in chromosome 17 aneuploidy was observed as a function of the SAR value, which the researchers described as a genotoxic effect. Control experiments conducted without any RF radiation across a temperature range of 34.5 to 38.5 °C showed that elevated temperature was not associated with the increased aneuploidy or the changes in centromeric DNA replication seen after RF exposure.

Elliptically polarized magnetic fields do not alter immediate early response genes expression levels in human glioblastoma cells

Unknown authors · 2002

Researchers analyzed expression of immediate early response genes c-fos, c-jun, and c-myc in human glioblastoma T98G cells exposed to 1-500 μT 60 Hz elliptically polarized magnetic fields for up to 3 h. No statistically significant differences were found in gene expression ratios at both transcriptional and translational levels for c-fos and c-jun at 30 min and for c-myc at 180 min after serum stimulation. Similarly, exposure to linearly or circularly polarized 500 μTr fields produced no significant change in expression ratios at both transcriptional and post-transcriptional levels.

Exposure to power frequency magnetic fields suppresses X-ray-induced apoptosis transiently in Ku80- deficient xrs5 cells

Unknown authors · 2002

Researchers exposed Ku80-deficient xrs5 cells and Ku80-proficient CHO-K1 cells to ELF electromagnetic fields. ELF field exposure alone did not affect cell survival, cell cycle distribution, or protein expression in either cell line. In xrs5 cells, ELF exposure after irradiation inhibited G1 cell cycle arrest, increased bcl-2 expression, and decreased p53, phospho-p53, caspase-3, and p21 protein levels. ELF exposure for 10 hours after irradiation reduced X-ray-induced apoptosis in xrs5 cells from about 1.7% to 0.7%, but this effect was not observed in CHO-K1 cells.

Decreased DNA repair rates and protection from heat induced apoptosis mediated by electromagnetic field exposure

Unknown authors · 2002

DNA damage and apoptosis in the immature mouse cerebellum after acute exposure to a 1 mT, 60 Hz magnetic field

Unknown authors · 2002

Researchers exposed 10-day-old mice to a 1 mT, 60 Hz magnetic field for 2 hours and measured DNA damage at multiple time points using the alkaline comet assay. They also measured apoptosis in the external granule cell layer of the cerebellum at 0 and 24 hours using the TUNEL assay. Increased DNA damage was detected by tail ratio at 2 hours but not by the other comet assay parameters, and no increase in apoptosis was observed compared to sham-exposed mice.

Effects of high- frequency electromagnetic fields on DNA strand breaks using comet assay method

Miyakoshi, J., Yoshida, M., Tarusawa, Y., et al. · 2002

Induction of DNA strand breaks by intermittent exposure to extremely-low-frequency electromagnetic fields in human diploid fibroblasts

Unknown authors · 2002

Human diploid fibroblasts were exposed to continuous or intermittent ELF-EMF at 50 Hz, sinusoidal, for 24 hours at 1000 microT. The alkaline and neutral comet assays were used to evaluate DNA single-strand and double-strand breaks. Intermittent fields reproducibly resulted in a significant increase of DNA strand break levels, mainly DSBs, compared to non-exposed controls. The highest DNA strand break levels occurred with 5 minutes field-on and 10 minutes field-off intermittence.

Lack of Mutation Induction with Exposure to 1.5 GHz Electromagnetic Near Fields Used for Cellular Phones in Brains of Big Blue Mice.

Takahashi S et al. · 2002

Researchers investigated the mutagenic potential of 1.5 GHz electromagnetic near fields using brain tissues of Big Blue mice. Male BBM were locally exposed to EMF in the head region at 2.0, 0.67, and 0 W/kg specific absorption rate for 90 min/day, 5 days/week, for 4 weeks. There was no significant variation in the frequency of independent mutations of the lacI transgene in the brains. Deletion mutations were slightly increased in both the high and low EMF exposure groups as compared with the sham-exposed group, but the differences were not statistically significant.

DNA Damage in human leukocytes after acute in vitro exposure to a 1.9 GHz pulse-modulated radiofrequency field.

McNamee JP et al. · 2002

Blood cultures from human volunteers were exposed to an acute 1.9 GHz pulse-modulated radiofrequency (RF) field for 2 h using a series of six circularly polarized, cylindrical waveguides. Mean specific absorption rates (SARs) ranged from 0 to 10 W/kg and the temperature within the cultures during the exposure was maintained at 37.0 ± 0.5°C. DNA damage was quantified in leukocytes by the alkaline comet assay and the cytokinesis-block micronucleus assay. No evidence of increased primary DNA damage was detected by the comet assay and no significant differences in micronucleus frequency were found at any SAR tested.

DNA damage and micronucleus induction in human leukocytes after acute in vitro exposure to a 1.9 GHz continuous-wave radiofrequency field.

McNamee JP et al. · 2002

Human blood cultures were exposed to a 1.9 GHz continuous-wave radiofrequency field for 2 hours at SARs of 0.0, 0.1, 0.26, 0.92, 2.4, and 10 W/kg while temperature was maintained at 37.0 ± 0.5°C. DNA damage was measured immediately after exposure using the alkaline comet assay with four parameters, and micronucleus formation was assessed using the cytokinesis-block micronucleus assay. No evidence of increased primary DNA damage was detected at any SAR tested. There was no significant difference in micronucleus incidence between exposed cultures and sham controls at any SAR.

Exposure to global system for mobile communication (GSM) cellular phone radiofrequency alters gene expression, proliferation, and morphology of human skin fibroblasts.

Pacini S et al. · 2002

Researchers exposed human skin fibroblasts to GSM cellular phone radiofrequency for 1 hour. GSM exposure induced alterations in cell morphology and increased expression of mitogenic signal transduction genes, cell growth inhibitors, and apoptosis-related genes. A significant increase in DNA synthesis and intracellular mitogenic second messenger formation corresponded with high expression of MAP kinase family genes.

The microarray study on the stress gene transcription profile in human retina pigment epithelial cells exposed to microwave radiation.

Liu X, Shen H, Shi Y, Chen J, Chen Y, Ji A. · 2002

Genotoxicity of radiofrequency signals. I. Investigation of DNA damage and micronuclei induction in cultured human blood cells.

Tice RR, Hook GG, Donner M, McRee DI, Guy AW. · 2002

DNA damage in leukocytes was assessed with the alkaline comet assay and chromosomal damage in lymphocytes with the micronucleus assay. No significant increase in DNA damage was seen after 3 or 24 hours, and no increase in micronucleated lymphocytes occurred after 3 hours. However, 24-hour exposures at 5.0 or 10.0 W/kg significantly increased micronucleated lymphocytes about fourfold, regardless of signal type, modulation, or frequency.

Cytogenetic damage in human lymphocytes following GMSK phase modulated microwave exposure.

d'Ambrosio G, MassaR, Scarfi MR, Zeni O · 2002

Researchers exposed human peripheral blood cultures to 1.748 GHz microwaves, either as continuous wave or phase-only modulated wave, for 15 minutes. The study measured cell proliferation kinetics and micronucleus frequency to look for genotoxic effects. No changes in cell proliferation kinetics were found after either type of exposure. A statistically significant micronucleus effect was found following exposure to the phase modulated field, but not after continuous wave exposure. The researchers suggested these results indicate a genotoxic power of the phase modulation itself.

The Effect of 835.62 MHz FDMA or 847.74 MHz CDMA Modulated Radiofrequency Radiation on the Induction of Micronuclei in C3H 10T½ Cells. Radiat.

Bisht KS, Moros EG, Straube WL, Baty JD, Roti Roti JL · 2002

Researchers exposed C3H 10T½ cells to 835.62 MHz FDMA or 847.74 MHz CDMA modulated radiofrequency radiation to determine whether it caused micronuclei to form. Cells were exposed at power levels of 3.2 or 4.8 W/kg for CDMA and 3.2 or 5.1 W/kg for FDMA, for durations of 3, 8, 16, or 24 hours. In three repeat experiments, no exposure condition produced a significant increase in micronuclei compared to sham-exposed cells.

Study of low-intensity 2450-MHz microwave exposure enhancing the genotoxic effects of mitomycin C using micronucleus test and comet assay in vitro.

Zhang MB, He JL, Jin LF, Lu DQ. · 2002

Researchers studied whether 2450-MHz microwave radiation interacts with the chemical mitomycin C (MMC) to produce genotoxic effects in human lymphocytes in vitro. Blood cells from a male donor and a female donor were exposed to 2450-MHz microwaves at 5.0 mW/cm2 for 2 h, to MMC alone for 24 h, or to MMC for 24 h following microwave exposure. Microwave exposure alone did not significantly increase comet lengths compared with controls, but combined microwave plus MMC exposure produced significantly longer comet lengths than MMC alone at doses of 0.025 microgram/mL or higher.

Micronucleus induction after whole-body microwave irradiation of rats.

Trosic I, Busljeta I, Kasuba V, Rozgaj R. · 2002

Researchers exposed adult male Wistar rats to continuous 2450 MHz radiofrequency microwave radiation for 2 hours a day, 7 days a week, for up to 30 days, at a power density of 5–10 mW/cm2. Peripheral blood smears were examined for micronuclei in polychromatic erythrocytes as an indicator of genotoxicity. Micronuclei per 1000 PCEs were significantly increased after eight irradiation treatments compared with sham-exposed controls. The researchers noted that an adaptive mechanism in both erythrocytopoiesis and genotoxicity likely appeared during the subchronic irradiation treatment.

Induction of micronuclei in mice exposed to static magnetic fields

Unknown authors · 2001

Chromosomal aberrations in lymphocytes of employees in transformer and generator production exposed to electromagnetic fields and mineral oil

Unknown authors · 2001

Exposure of Caenorhabditis elegans to extremely low frequency high magnetic fields induces stress responses.

Unknown authors · 2001

Researchers examined responses of the small heat shock protein gene hsp-16 in transgenic Caenorhabditis elegans exposed to electromagnetic fields. Expression of the hsp-16-lacZ gene was enhanced when transgenic animals were exposed to magnetic fields up to 0.5 T at 60 Hz. The hsp-16 promoter was more efficiently expressed at the embryonic than at the post-embryonic stage irrespective of exposure. Promoter activity was more sensitive to the stimulus in the intestine at the post-embryonic stage.

Induction and rejoining of DNA double-strand breaks in normal human skin fibroblasts after exposure to radiation of different linear energy transfer: possible roles of track structure and chromatin organization.

Unknown authors · 2001

Researchers exposed normal human skin fibroblasts to nitrogen ions at LETs of 80-225 keV/microm and measured DNA double-strand breaks using pulsed-field gel electrophoresis. DSB yield increased from 4.5 +/- 0.2 to 10.0 +/- 0.3 DSBs per particle traversal when LET increased from 80 to 225 keV/microm. Fragment size distribution showed an excess of fragments at 50-200 kbp and around 1 Mbp, and repair was slower at higher LET with nonrandom distributions persisting after 1 hour.

Micronucleus induction in Syrian hamster embryo cells following exposure to 50 Hz magnetic fields, benzo(a)pyrene, and TPA in vitro

Unknown authors · 2001

Micronuclei in the peripheral blood and bone marrow cells of rats exposed to 2450 MHz radiofrequency radiation.

Vijayalaxmi et al. · 2001

Eight adult male Sprague-Dawley rats were exposed to 2450 MHz RFR in circularly polarized waveguides, and eight sham-exposed rats were kept in similar waveguides without RFR transmission. Four rats treated with mitomycin-C served as positive controls, and all rats were necropsied 24h after exposure to examine peripheral blood and bone marrow smears for micronuclei in polychromatic erythrocytes. The incidence of micronuclei per 2000 polychromatic erythrocytes was not significantly different between RFR-exposed and sham-exposed rats.