Unknown authors · 2007
Researchers used the sister chromatid exchange technique to test the clastogenic potential of extremely low frequency electromagnetic fields on human peripheral blood lymphocytes. SCE frequencies were scored in dividing lymphocytes from six healthy male donors across two experimental rounds for reproducibility. Lymphocyte cultures were exposed to 50 Hz sinusoidal or square magnetic fields, continuous or pulsed, at 1 µT or 1 mT for 72 hours. A significant increase in SCEs per cell was observed in exposed groups compared to controls in both rounds. The highest SCE frequency in the first round was 10.03 for a square continuous field, and 10.39 for a square continuous field was the second highest in the second round.
Unknown authors · 2007
Researchers exposed UVW human glioma cells to ELF-EMF at 1 mT (50 Hz) for 12 hours. This exposure alone produced 0.011 mutations per locus per cell, a 3.75-fold increase over unexposed controls. ELF-EMF also increased the mutagenic effect of 0.3 Gy and 3 Gy gamma-irradiation by 2.6-fold and 2.75-fold respectively. The lower radiation dose of 0.3 Gy induced more than 10 times more mutations per unit dose than 3 Gy, indicating hypermutability at low dose.
Unknown authors · 2007
Researchers exposed Wistar rats to a 50 Hz, 1 mT magnetic field for either 4 hours (acute) or 4 hours per day for 45 days (long-term). Chromosomal aberration analysis showed no statistically significant differences between exposed and control groups. However, the long-term exposure group had a significantly higher micronucleus frequency than controls (p<0.01). Both acute and long-term exposure significantly reduced the mitotic index (p<0.001 and p<0.01) and the PCE/NCE ratio (p<0.001 and p<0.01).
Unknown authors · 2007
Unknown authors · 2007
Researchers exposed THP1 cells to a static magnetic field of 250 mT for 1, 2, or 3 hours to investigate antioxidant enzyme activity, the labile zinc fraction, and DNA damage. Cell viability was slightly lower in the exposed groups compared to sham-exposed cells. Malondialdehyde concentration and the activities of glutathione peroxidase, catalase, and superoxide dismutase did not change significantly in group 3 compared to sham. Comet assay showed no DNA damage in groups 1 and 2, but a low level of single-strand breaks appeared in group 3, while the oxidative DNA lesion 8-oxodGuo remained unchanged. The labile zinc fraction decreased in all exposure groups.
Unknown authors · 2007
Researchers exposed the U-251 MG human glial cell line to 60 GHz millimeter wave radiation for 1 to 33 hours at two power densities. They measured transcription factor activation, mRNA levels, and protein amounts for the chaperone genes clusterin and HSP70. No significant changes were found in gene transcription, mRNA, or protein levels for the tested exposure conditions.
Zeni O et al. · 2007
Researchers exposed human whole blood samples from healthy donors to terahertz radiation for 20 min. They tested frequencies of 120 GHz at 0.4 mW g-1 SAR and 130 GHz at 0.24, 1.4, and 2 mW g-1 SAR. Chromosomal damage and cell cycle kinetics were assessed using the cytokinesis block micronucleus technique. Samples exposed to 130 GHz at SAR levels of 1.4 and 2 mW g-1 were also examined for primary DNA damage with the alkaline comet assay. The results indicate that terahertz exposure under these conditions did not induce genotoxicity or alter cell cycle kinetics in human blood cells.
Unknown authors · 2007
Researchers exposed whole wild-type tomato plants to electromagnetic radiation and observed rapid accumulation of bZIP mRNA in the terminal leaf. When only the oldest leaf was irradiated, bZIP mRNA accumulated both locally and systemically in distant leaves, though systemic accumulation was delayed. In the ABA-deficient mutant Sitiens, bZIP accumulation was reduced in both local and distant leaves, while Pin2 mRNA accumulation was stronger locally but absent systemically. Similar responses occurred in a jasmonic acid mutant and in wild-type plants treated with an ABA biosynthesis inhibitor. Calcium antagonists applied to the exposed leaf abolished both local and systemic bZIP transcript increases.
Juutilainen J, Heikkinen P, Soikkeli H, Mäki-Paakkanen J. · 2007
Chauhan V et al. · 2007
Researchers exposed human-derived cell lines TK6, HL60, and Mono-Mac-6 to intermittent 1.9 GHz pulse-modulated RF fields for 6 hours at SARs of 0, 1, and 10 W/kg. Cell viability, apoptosis, and cell cycle kinetics were measured immediately after exposure and 18 hours later. Cytokine expression (TNFA, IL1B, IL6, IL8, IL10, IL12) was also assessed. No detectable changes in cell viability, cell cycle kinetics, apoptosis, or cytokine expression were observed in any exposed group compared to sham controls. The positive heat-shock control showed decreased viability, increased apoptosis, and a G(2)/M cell cycle block.
Chauhan V et al. · 2007
Researchers examined the effect of RF field exposure on late onset gene expression in U87MG cells after a 24 h exposure period. A human monocyte-derived cell line (MM6) was exposed to intermittent RF fields for 6 h and gene expression was assessed immediately and at 18 h postexposure. Both cell lines were exposed to 1.9 GHz pulse-modulated RF fields for 6 or 24 h at SARs of 0.1-10.0 W/kg. The study found no evidence that nonthermal RF field exposure altered gene expression in either U87MG or MM6 cells relative to nonirradiated controls. Heat shock at 43°C for 1 h altered the expression of well-characterized heat-shock proteins in both cell lines.
Speit G, Schütz P, Hoffmann H. · 2007
Researchers exposed ES1 cells to 1800 MHz RF-EMF at 2 W/kg SAR with intermittent exposure and tested for DNA damage using the alkaline comet assay and micronucleus test. They also tested V79 Chinese hamster cells and found no genotoxic effect in either assay. Quality control measures were used to rule out test performance issues, exposure failure, or evaluation bias.
Panagopoulos DJ, Chavdoula ED, Nezis IP, Margaritis LH · 2007
Researchers used the TUNEL assay to detect DNA fragmentation in early and mid-oogenesis stages of Drosophila melanogaster. Flies were exposed to GSM 900-MHz or DCS 1800-MHz radiation from a mobile phone for a few minutes daily over the first six days of adult life. Both radiation types induced DNA fragmentation in all cell types of the egg chamber, leading to degeneration of egg chambers. Germarium and stages 7-8 were the most sensitive developmental stages, with germarium even more sensitive than stages 7-8.
Zhao TY, Zou SP, Knapp PE. · 2007
Researchers exposed primary cultured neurons and astrocytes to GSM cell phone emissions at 1900 MHz for 2 hours. Neurons showed up-regulation of caspase-2, caspase-6, and Asc genes in both 'on' and 'stand-by' modes. Astrocytes showed up-regulation of the same genes only in 'on' mode and also up-regulated the Bax gene.
Baohong W et al. · 2007
Researchers exposed human lymphocytes to 1.8 GHz microwaves at a SAR of 3 W/kg, ultraviolet ray C (UVC), or both, then measured DNA damage using the comet assay. Microwave exposure alone did not produce significantly more DNA damage than the control group. When combined with UVC, microwave exposure was associated with reduced DNA damage at 1.5-hour incubation but increased DNA damage at 4-hour incubation, compared with UVC alone.
Zhao R, Zhang S, Xu Z, Ju L, Lu D, Yao G. · 2007
Researchers investigated whether 1800 MHz radiofrequency electromagnetic fields could influence gene expression in rat neurons. Among 1200 candidate genes, 24 were up-regulated and 10 were down-regulated after 24 hours of intermittent exposure at a SAR of 2 W/kg. The researchers concluded that gene expression in rat neurons could be altered by exposure to radiofrequency electromagnetic fields under their experimental conditions.
Buttiglione M et al. · 2007
Researchers exposed human neuroblastoma SH-SY5Y cells to 900 MHz radiofrequency radiation at 1 W/kg to study effects on gene expression and cell-cycle control. Short-term exposures produced a transient increase in Egr-1 mRNA levels along with activation of the MAPK subtypes ERK1/2 and SAPK/JNK. Exposure had an anti-proliferative effect, and a significant G2-M cell-cycle arrest was observed, with signs of apoptosis appearing after 24 hours. A significant decrease in mRNA levels of Bcl-2 and survivin genes, both linked to signaling between G2-M arrest and apoptosis, was also observed.
Unknown authors · 2006
Unknown authors · 2006
Researchers used the micronucleus test with CREST antibody staining to assess clastogenic and aneugenic effects of a 50 Hz, 650 muT magnetic field. Newborn mice were exposed during the entire 21-day intra-uterine period, and adult mice were exposed for the same duration. Newborn mice showed a significant increase in micronuclei frequencies, with most induced micronuclei being CREST-negative chromosome fragments. ELF exposure caused a two-fold increase in CREST-negative micronuclei and a four-fold increase in CREST-positive micronuclei in newborn mice. No significant effect was observed in exposed adult mice.
Paul AL, Ferl RJ, Meisel MW · 2006
Unknown authors · 2006
Researchers investigated effects of electromagnetic fields on DNA damage in preimplantation mouse embryos using gammaH2AX foci formation as an indicator. EMFs decreased the cleavage rate of preimplantation mouse embryos. The decreasing effect was related to DNA damage shown by gammaH2AX foci formation. Noise magnetic fields or wortmannin inhibited the EMF-induced gammaH2AX foci formation. EMFs could activate the DNA damage-repair mechanism by recruiting Rad50 to damaged DNA sites.
Unknown authors · 2006
Researchers investigated the effects of pulsed electric fields at 50 Hz on DNA of human lymphocytes using the comet assay. A significant amount of DNA damage was observed after exposure compared to controls. After 2 hours incubation at 37°C, a proportion of the damage was repaired. Hydrogen peroxide and gamma-irradiation increased the damage to lymphocytes exposed to pulsed electric fields according to the dose used, and the amount of repair was proportional to the damage.
Unknown authors · 2006
Unknown authors · 2006
Researchers exposed two human cell lines, neuronal SK-N-SH and monocytoid U937, to a 900 MHz RF signal pulsed at 217 Hz with a SAR of 0.2 W/kg. For SK-N-SH cells, they assessed effects using gene microarray, real-time PCR, Western blot for heat shock proteins, and flow cytometry for cell cycle and apoptosis. For U937 cells, they assessed effects using cell viability and cell cycle analysis. No significant difference was found between sham-exposed and radiofrequency-exposed cells in any assay or condition.
Unknown authors · 2006
Researchers exposed human whole-blood leukocytes and isolated lymphocytes to high power microwave pulses at 8.8 GHz for 40 minutes in a rectangular waveguide. The average specific absorption rate was about 1.6 kW/kg with a peak of about 300 MW/kg, and the sample temperature rose by 3.5 ± 0.1 °C. No statistically significant DNA damage was found immediately after exposure or after a 30-minute incubation at 37 °C. The authors concluded that the pulses did not induce DNA strand breaks, alkali-labile sites, or incomplete excision repair sites detectable by the alkaline comet assay.
