OBJECTIVETo study the effects of GSM 1800 MHz radiofrequency electromagnetic fields (RF EMF) on DNA damage in Chinese hamster lung (CHL) cells.

METHODSThe cells were intermittently exposed or sham-exposed to GSM 1800 MHz RF EMF (5 minutes on/10 minutes off) at a special absorption rate (SAR) of 3.0 W/kg for 1 hour or 24 hours. Meanwhile, cells exposed to 2-acetylaminofluorene, a DNA damage agent, at a final concentration of 20 mg/L for 2 hours were used as positive control. After exposure, cells were fixed by using 4% paraformaldehyde and processed for phosphorylated form of H2AX (gammaH2AX) immunofluorescence measurement. The primary antibody used for immunofluorescence was mouse monoclonal antibody against gammaH2AX and the secondary antibody was fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG. Nuclei were counterstained with 4, 6-diamidino-2-phenylindole (DAPI). The gammaH2AX foci and nuclei were visualized with an Olympus AX70 fluorescent microscope. Image Pro-Plus software was used to count the gammaH2AX foci in each cell. For each exposure condition, at least 50 cells were selected to detect gammaH2AX foci. Cells were classified as positive when more than five foci were detected. The percentage of gammaH2AX foci positive cells was adopted as the index of DNA damage.

RESULTSThe percentage of gammaH2AX foci positive cell of 1800 MHz RF EMF exposure for 24 hours (37.9 +/- 8.6)% or 2-acetylaminofluorene exposure (50.9 +/- 9.4)% was significantly higher compared with the sham-exposure (28.0 +/- 8.4)%. However, there was no significant difference between the sham-exposure and RF EMF exposure for 1 hour (31.8 +/- 8.7)%.

CONCLUSION1800 MHz RF EMF (SAR, 3.0 W/kg) for 24 hours might induce DNA damage in CHL cells.

Animals ; Cells, Cultured ; Cricetinae ; Cricetulus ; DNA Breaks, Double-Stranded ; radiation effects ; DNA Damage ; radiation effects ; Electromagnetic Fields ; adverse effects ; Fibroblasts ; chemistry ; radiation effects ; Radio Waves

No abstract available.
DNA Breaks, Double-Stranded/radiation effects ; Humans ; Radiation Injuries/*etiology ; Radiation Protection/instrumentation ; Radiation, Ionizing ; Radiotherapy Dosage ; Tomography, X-Ray Computed

OBJECTIVETo investigate the effects of 50 Hz magnetic fields (MF) on DNA double-strand breaks in human lens epithelial cells (hLECs).

METHODSThe cultured human lens epithelial cells were exposed to 0.4 mT 50 Hz MF for 2 h, 6 h, 12 h, 24 h and 48 h. Cells exposed to 4-nitroquinoline-1-oxide, a DNA damage agent, at a final concentration of 0.1 micromol/L for 1 h were used as positive controls.After exposure, cells were fixed with 4 % paraformaldehyde and for H2AX (gamma H2AX) immunofluorescence measurement. gamma H2AX foci were detected at least 200 cells for each sample. Cells were classified as positive when more than three foci per cell were observed. Mean values of foci per cell and percentage of foci positive cells were adopted as indexes of DNA double-strand breaks.

RESULTThe mean value of foci per cell and the percentage of gamma H2AX foci positive cells in 50 Hz MF exposure group for 24 h were (2.93 +/-0.43) and (27.88 +/-2.59)%, respectively, which were significantly higher than those of sham-exposure group [(1.77 +/-0.37) and (19.38+/-2.70)%, P <0.05], and the mean value of foci per cell and the percentage of gamma H2AX foci positive cells in 50 Hz MF exposure group for 48 h were (3.14 +/-0.35) and (31.00 +/-3.44)%, which were significantly higher than those of sham-exposure group (P <0.01). However there was no significant difference between 50 Hz MF exposure groups for 2 h, 6 h, 12 h and sham-exposure group for above two indexes (P >0.05).

CONCLUSION0.4 mT 50 Hz MF exposure for longer duration might induce DNA double-strand breaks in human lens epithelial cells in vitro.

Cells, Cultured ; DNA ; radiation effects ; DNA Breaks, Double-Stranded ; radiation effects ; DNA Damage ; radiation effects ; DNA Repair ; radiation effects ; Electromagnetic Fields ; Epithelial Cells ; metabolism ; radiation effects ; Humans ; Lens, Crystalline ; cytology

BACKGROUNDIt is desirable to minimize the risk of adverse radiation effects associated with percutaneous coronary intervention. The aim of this study was to determine the impact of prolonging the interval between coronary angiography and percutaneous coronary intervention on X-ray-induced DNA double-strand breaks in blood lymphocytes using γ-H2AX immunofluorescence microscopy.

METHODSBlood samples of eight patients were taken before the first exposure to ionizing radiation, 10 minutes, 20 minutes, 30 minutes, 1 hour, and 24 hours after the last exposure to determine the γ-H2AX foci repair kinetics. Fifty-eight patients undergoing percutaneous coronary intervention were randomized to an intermittent radiation exposure group and a continuous radiation exposure group. Blood samples were taken before coronary angiography and 15 minutes after the last exposure. By enumerating γ-H2AX foci, the impact of prolonging the interval on DNA double-strand breaks was investigated. Student t-test was used to compare the difference in DNA double-strand breaks between the two groups.

RESULTSAn increase in foci was found in all patients received percutaneous coronary intervention. The maximum number of γ-H2AX foci was found 10-20 minutes after the end of the last exposure. There was no statistically significant difference between the two groups in γ-H2AX foci at baseline. On average there were (0.79 ± 0.15) γ-H2AX foci induced by interventional X-rays per lymphocyte in the continuous radiation exposure group and (0.66 ± 0.21) in the intermittent radiation exposure group after exposure (P < 0.05).

CONCLUSIONSA significant number of γ-H2AX foci develop following the percutaneous coronary intervention procedures. The number of X-ray-induced DNA double-strand breaks may be decreased by prolonging the interval time between coronary angiography and percutaneous coronary intervention to 30 minutes.

Adult ; Coronary Angiography ; adverse effects ; DNA Breaks, Double-Stranded ; radiation effects ; Dose-Response Relationship, Radiation ; Female ; Humans ; Lymphocytes ; metabolism ; radiation effects ; Male ; Middle Aged ; Percutaneous Coronary Intervention ; adverse effects

OBJECTIVETo investigate whether 50 Hz magnetic fields (MF) can change the gene expression profile in MCF-7 cells and to screen MF responsive genes.

METHODSIn vitro cultured MCF-7 cells were continuously exposed or sham-exposed to 0.4 mT of 50 Hz MF for 24 hours. Affymetrix Human Genome Genechips (U133A) were applied to analyze gene expression profiles in MF exposed and sham-exposed MCF-7 cells and the data were processed with Genechip data analysis software MAS 5.0 and DMT 3.0. Real-time RT-PCR assay was employed to examine the differentially expressed genes.

RESULTThirty differentially expressed genes were screened with 100 % consistency change calls in the MF exposed MCF-7 cells. Six independent real-time RT-PCR analyses showed that SCNN1A, METTL3 and GPR137B were slightly but statistically significantly changed in MCF-7 cells after exposure to 50 Hz MF (P<0.05), while other analyzed genes exhibited slight up-and down-fluctuations in expressions and no increase or decrease in each gene expression reached statistical significance (P>0.05).

CONCLUSIONThe present study identified three 50 Hz MF responsive genes in MCF-7 cells and the biological consequences of expression changes in these MF responsive genes need to be further investigated.0.4 mT 50 Hz MF exposure for longer duration might induce DNA double-strand breaks in human lens epithelial cells in vitro.

Cell Line, Tumor ; DNA Breaks, Double-Stranded ; radiation effects ; Electromagnetic Fields ; Gene Expression ; radiation effects ; Gene Expression Profiling ; Humans ; Polymerase Chain Reaction ; Radio Waves ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Cells, Cultured