Unknown authors · 1999
Researchers investigated the effect of 50 Hz magnetic fields on the cytosolic calcium oscillator in Jurkat E6.1 cells at field strengths from 0 to 0.40 mT root mean square. The total spectral power of the cytosolic Ca2+ oscillator was reduced by magnetic field exposure and the effect increased in a dose-response manner. This reduction was also observed in the 0-10 mHz subinterval of the oscillation spectrum, while higher frequency subintervals showed no significant change.
Unknown authors · 1999
Researchers exposed human leukemia T-cells to 50 Hz magnetic fields (the same frequency as electrical power lines) and measured calcium oscillations inside the cells. They found that magnetic field exposure reduced these calcium signals in a dose-dependent manner - the stronger the field, the greater the reduction. This matters because calcium signaling is crucial for immune cell function and communication.
Linz et al. · 1999
Researchers tested the effects of radio frequency fields at 180, 900, and 1800 MHz on the electrical properties of isolated ventricular myocytes from guinea pigs and rats. The fields were applied using rectangular waveguides or a TEM cell at specific absorption rates up to 880 mW/kg, with 900 and 1800 MHz signals pulsed to the GSM standard. None of the tested electrophysiological parameters, including membrane potential, action potential, L-type calcium current, and potassium currents, were significantly changed by RF exposure. Lowering the temperature from 36°C to 24°C reduced current amplitude by almost 50% and shifted voltage dependence by about 5 mV, but RF exposure at the lower temperature still did not affect L-type calcium current.
Gandhi OP, Lazzi G, Tinniswood A, Yu QS, · 1999
Researchers compared numerical and experimental methods for determining SAR and radiation patterns of handheld wireless telephones at 835 and 1900 MHz. Peak 1-g SARs ranged from 0.13 to 5.41 W/kg, yet agreement between calculated and measured data was generally within plus or minus 20%. The study noted that for a maximum radiated power of 600 mW at 800/900 MHz, peak 1-g SARs can be higher than 1.6 W/kg unless antennas are carefully designed and placed further away from the head.
Unknown authors · 1999
Researchers exposed HBL-100 cells and normal human mammary epithelial cells to 60 Hz EMF at flux densities of 0.1, 1.0, and 10.0 Gauss for periods ranging from 20 min to 24 h. Gene expression was quantitated using ribonuclease protection assays. EMF exposure had no statistically significant effect on basal levels of c-myc transcripts in either human breast cell model, and had no effect on alterations in c-myc expression induced by 12-O-tetradecanoylphorbol-13-acetate. Transcript levels of c-erbB-2, p53, p21, GADD45, bax, bcl-x, mcl-1, and c-fos were also unaffected by EMF exposure.
Unknown authors · 1999
Researchers exposed human breast cells to 60 Hz magnetic fields (the same frequency as household electricity) at various strengths for up to 24 hours to see if EMF exposure would alter cancer-related genes. The study found no significant changes in gene expression for key cancer markers like c-myc, p53, and others, suggesting 60 Hz magnetic fields don't promote breast cancer through genetic mechanisms.
Unknown authors · 1999
Researchers exposed human breast cells to 60 Hz magnetic fields at various strengths (0.1 to 10 Gauss) for up to 24 hours to test whether power line frequencies could trigger cancer-related gene changes. The study found no significant effects on cancer-associated genes including c-myc, p53, and others, suggesting 60 Hz EMF is unlikely to promote breast cancer through direct gene expression changes.
Morrissey JJ et al. · 1999
Researchers investigated the effects of a one-hour exposure of mice to a 1.6-GHz radiofrequency signal, either continuous wave or pulse-modulated at 11 Hz (IRIDIUM), on c-fos gene expression in the brain. C-fos expression was not significantly elevated until exposure levels exceeded six times the peak dose and 30 times the whole-body average dose relative to human cellular telephone exposure limits. The pattern of c-fos elevation in limbic cortex and subcortex areas was consistent with a stress response due to thermal perception and restraint, not a direct interaction of IRIDIUM energy with brain tissue.
Trosic I, Matausicpisl M, Radalj Z, Prlic I, · 1999
The remaining 20 rats served as control. Exposed rats showed a decreasing tendency in total leukocyte and relative lymphocyte counts and a slight increase in granulocyte and erythrocyte counts.
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.
Khadir R, Morgan JL, Murray JJ. · 1999
Researchers investigated the effects of a sinusoidal 60 Hz magnetic field on free radical production, degranulation, and viability in human neutrophils. Exposure of unstimulated human neutrophils to the magnetic field did not affect the functions examined. When cells were also stimulated with PMA, exposure to a 22 mT, 60 Hz magnetic field induced significant increases in superoxide anion production of 26.5% and in β-glucuronidase release of 53%. Release of lysozyme and lactate dehydrogenase was unchanged by the magnetic field, whether the cells were stimulated or not.
E.G Novoselova, E.E Fesenko, V.R Makar, V.B Sadovnikov · 1999
Researchers tested the effect of 8.15–18 GHz microwave radiation at a power density of 1 μW/cm2 on TNF production and immune response. A single 5-hour whole-body exposure induced a significant increase in TNF production in peritoneal macrophages and splenic T cells, and the mitogenic response in T lymphocytes also increased. The activation of cellular immunity was observed within 3 days after exposure. A diet containing β-carotene, α-tocopherol, and ubiquinone Q9 increased the activity of macrophages and T cells from irradiated mice.
Paul Raj R, Behari J, Rao AR · 1999
The effect of exposing rats to amplitude-modulated radiofrequency radiation (112 MHz modulated to 16 Hz) during development and growth was examined. Wistar rats 35 days old exposed at 1.0 mW/cm2 (SAR 0.75 W/kg) for 35 days showed enhanced ornithine decarboxylase activity and Ca2+ efflux in brain.
Adey WR et al. · 1999
Researchers tested an 836.55 MHz NADC-modulated field in a 2-year bioassay with fetal exposure in Fischer 344 rats. Of 236 original rats, 182 (77%) survived to termination at age 709-712 days. There was no evidence of tumorigenic effects in the CNS from TDMA field exposure. Exposed animals showed trends toward reduced incidence of spontaneous CNS tumors (P < 0.16) and ENU-induced CNS tumors (P < 0.16). In preterm rats where neural tumors caused death, fields decreased ENU-induced tumor incidence (P < 0.03).
Jauchem JR, Frei MR, Ryan KL, Merritt JH, Murphy MR · 1999
The study investigated the lack of effects on heart rate and blood pressure in ketamine-anesthetized rats briefly exposed to ultra-wideband electromagnetic pulses. Exposures at a repetition frequency of 1 kHz for 0.5 s or to repetitive pulse trains for a total of 2 min resulted in no significant changes in heart rate or mean arterial blood pressure. These results suggest that acute whole-body exposure to UWB pulses does not have a detrimental effect on the cardiovascular system.
Unknown authors · 1999
Researchers conducted a population-based case-control study across England, Wales, and Scotland. They measured household and school magnetic fields for 2226 matched case-control pairs and estimated average exposure in the year before diagnosis. For children with mean exposures above 0.2 microT compared to below 0-1 microT, the adjusted odds ratio for all malignant disease combined was 0.87 (95% CI 0.56-1.35).
Unknown authors · 1999
Unknown authors · 1999
Unknown authors · 1999
Researchers evaluated the effect of a 60 Hz electromagnetic field on NF-kappaB or AP-1-dependent reporter gene expression in human U937 leukemia cells. Reporter genes were electroporated into the cells and pathway activation was measured by CAT protein using CAT ELISA. Magnetic field intensities of 0.08, 0.1, 1.0, and 1.3 mT had no effect on either signaling pathway.
Unknown authors · 1999
Researchers studied DNA migration using the comet assay in brain cells of CBA mice exposed continuously to 50 Hz, 0.5 mT magnetic fields for 2 hours, 5 days, or 14 days. No differences were observed in mice exposed for 2 hours or 5 days compared with controls. Mice exposed for 14 days showed significantly extended DNA migration (0.02 < p < 0.05).
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.
Schonborn F, Burkhardt M, Kuster N · 1998
In order to investigate the differences in absorption between adults and children due to their differing anatomies, simulations were performed using head phantoms based on MRI scans of an adult and two children aged 3 and 7 years. Ten different tissue types were distinguished and all simulations were performed using a commercial code based on the finite integration technique. The differences in absorption were investigated for the frequencies of 900 MHz and 1,800 MHz using 0.45 lambda dipoles instead of actual mobile phones. The results revealed no significant differences in the absorption of electromagnetic radiation in the near field of sources between adults and children.
Wagner, P, Roschke, J, Mann, K, Hiller, W, Frank, C · 1998
Researchers recorded all-night polysomnographies of 24 healthy male subjects with and without exposure to a circularly polarized 900 MHz pulsed electromagnetic field at 0.2 W/m². Suppression of REM sleep and a sleep-inducing effect under field exposure did not reach statistical significance, so previous results indicating alterations of these sleep parameters could not be replicated. Spectral power analysis also did not reveal any alterations of the EEG rhythms during EMF exposure.
Unknown authors · 1998
Malyapa RS et al. · 1998
Researchers exposed rats to 2450 MHz microwave radiation (the same frequency used in microwave ovens and some WiFi devices) for 2 hours to see if it would damage DNA in brain cells, as a previous study had suggested. They found no DNA damage in either the brain's cortex or hippocampus regions, contradicting the earlier research. This study suggests that short-term exposure to this type of radiation at moderate levels may not cause immediate genetic damage to brain cells.
