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.
Unknown authors · 1998
Researchers assessed whether a 60-Hz magnetic field at 0.1 mT could reproduce earlier reported transcription changes in c-fos, c-jun, and c-myc oncogenes in CEM-CM3 cells. Cells were exposed for 15, 30, 60, or 120 minutes to the field or to a sham condition with coils in bucking mode. Transcription rates measured by nuclear run-on assay and transcript levels measured by Northern analysis showed no significant difference between exposed and sham or control cells at any time point.
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.
Fetter JG, Ivans V, Benditt DG, Collins J, · 1998
Researchers tested whether NADC/TDMA-50 digital telephones interfere with Medtronic ICDs in 41 patients. No ICDs in the 41 patients were affected by electromagnetic interference from the telephone during the in vivo study. In vitro antenna-generated field testing showed GSM and TDMA-50 modulation frequencies did not cause ICD sensing interference at predicted electric field intensity. Near-field tests with analog and digital phones in service or test mode also showed no interaction with normal ICD operation. However, a static magnetic field from a phone placed within 0.5 cm of the ICD activated the reed switch, temporarily suspending ventricular tachycardia and fibrillation detection.
Schlegel RE, Grant FH, Raman S, Reynolds D · 1998
Researchers tested 29 pacemaker models with five phone standards in a large-scale in-vitro study. Only a few pacemaker models accounted for most interactions. One phone technology produced interactions in 21% of tests, while other standards caused little or no interaction. The study also found that phone orientation and the presence of an injected ECG signal influenced interactions. The study supports the recommendation to maintain a separation distance of at least 6 inches between pacemakers and wireless phones.
Glenister H · 1998
The study aimed to investigate how mobile phones affect electromedical devices. The Medical Devices Agency found emergency services' radio handsets were the most likely to cause interference. The agency recommends switching off cell telephones in theatres, treatment areas, and at patients' bedsides where sensitive medical devices are in use.
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.
Bassen HI, Moore HJ, Ruggera PS · 1998
An in vitro study tested three ICD models for susceptibility to electromagnetic interference from two digital cellular phones and one analog cellular phone operating at maximum output power. All digital cellular phones produced electromagnetic interference to varying degrees. TDMA-modulated digital phones caused the most pronounced effects, including high-voltage firing and inhibition of pacing output. Interference occurred only when phones were within 2.3–5.8 cm of the ICD pulse generator submerged 0.5 cm in 0.18% saline, and performance returned to baseline when phones were removed.
Nakamura et al. · 1998
Researchers exposed pregnant rats to microwaves at 2 mW/cm2, 2450 MHz for 90 minutes and measured natural killer cell activity and beta-endorphin levels. Microwave exposure raised colonic temperature and increased beta-endorphin in blood and anterior pituitary but did not change corticosterone. Naloxone administered before exposure increased natural killer cell activity and beta-endorphin in blood and placenta of pregnant rats.
Loscher W, Kas G, · 1998
Researchers observed behavioral abnormalities, reduced milk yield, and increased health problems in a herd of cows near a TV and cell phone transmitting antenna over two years. Evaluation of possible factors found no explanation other than high-frequency electromagnetic fields. In an experiment, a cow with abnormal behavior was moved 20 km from the antenna and normalized completely within five days, but symptoms returned when the cow was brought back. The researchers suggested the abnormalities might be related to electromagnetic field exposure, with power densities measured at 0.02-7 mW/m2.
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.
Unknown authors · 1997
Unknown authors · 1997
Researchers studied intracellular calcium signaling in Jurkat E6-1 human T-leukemia cells during and after exposure to a 60 Hz magnetic field. Cells were labeled with Fluo-3, stimulated with anti-CD3 antibody, and analyzed by flow cytometry for calcium-dependent fluorescence.
Malyapa RS et al. · 1997
Researchers used the alkaline comet assay to test whether 2450 MHz radiation causes DNA damage in cultured mammalian cells. Exponentially growing U87MG and C3H 10T1/2 cells were exposed to 2450 MHz CW radiation at SARs of 0.7 and 1.9 W/kg for durations of 2 h, 2 h followed by 4-h incubation, 4 h, and 24 h. No significant differences were observed between the test group and the controls after exposure.
Chattopadhyay SK, Toews KA, Butt S, Barlett R, Brown HD · 1997
Acetylcholinesterase and NADPH cytochrome-P450 reductase show the same temperature versus activity profile in AOT reverse micelles as in buffered dilute solution. In reverse micelles, inhibitors such as propidium and d-tubocurarine have much less effect on indophenol-acetate hydrolysis than in dilute solution, while other inhibitors act the same. The internal pH of reverse micelles depends on available hydrogen ions, low-molarity buffers often cannot keep pH constant, and proton-yielding reactions proceed dramatically faster than in dilute solution at the same acidic pH.
Nakamura H, Seto T, Nagase H, Yoshida M, Dan S, Ogino K. · 1997
Pregnant rats exposed to microwaves showed a significant reduction in splenic natural killer cell activity, while no such reduction was seen in exposed virgin rats. Corticosterone and ACTH increased, and oestradiol decreased, in both exposed virgin and pregnant rats, while beta-endorphin and progesterone increased significantly only in pregnant rats.
Donnellan M, McKenzie DR, French PW · 1997
Researchers exposed a mast cell line, RBL-2H3, to 835 MHz radiation for 20 minutes, three times per day for 7 days at a power density of 8.1 +/- 3 mW/cm2. From day 4 onward, DNA synthesis and cell replication increased, cell morphology changed, and beta-hexosaminidase release was significantly enhanced compared to unexposed cultures. No effects were seen on cytoskeletal protein synthesis or beta-actin mRNA levels. Morphological changes persisted following subculture for at least 7 days in the absence of further exposure.
Cleary, SF, Cao, G, Liu, LM, Egle, PM, Shelton, KR · 1997
Researchers investigated stress protein induction in HeLa and CHO cells following a 2-hour exposure to radiofrequency or microwave radiation. Cells were exposed under isothermal conditions maintained at 37 ± 0.2 °C. Neither microwave nor RF radiation had a detectable effect on stress protein induction.
Fiorani M et al. · 1997
Researchers investigated the effects of 50 Hz magnetic fields (0.2–0.5 mT) on rabbit red blood cells exposed at the same time to an oxygen radical-generating system, Fe(II)/ascorbate. A 0.5 mT magnetic field had no effect on intact red blood cells, but when cells were already under oxidative stress, exposure caused a significant further decay in hexokinase activity of about 20% and a twofold increase in methemoglobin production. The researchers concluded that the magnetic fields studied were able to potentiate the cellular damage induced in vitro by oxidizing agents.
Unknown authors · 1996
Researchers transfected HeLa cells with plasmids containing c-fos upstream regulating regions up to -700 base pairs linked to a CAT reporter gene. The cells were exposed to a 60 Hz electromagnetic field at 60 mGrms. CAT expression increased above control levels after 5 minutes of exposure, peaked at 20 minutes, and returned to basal levels after 40 minutes. Deletion analysis identified a responsive region of 138 base pairs from -363 to -225 containing SRE/AP-1 sites.
Unknown authors · 1996
Researchers exposed human melanoma MeWo cells to a 50-Hz, 400-mT extremely low frequency magnetic field and measured mutations in the hypoxanthine-guanine phosphoribosyl transferase gene. The mutant frequency increased with longer exposure periods and higher induced current intensities. Mutations induced by X-rays were enhanced by the magnetic field exposure. No significant increase in mutant frequency occurred when DNA replication was inhibited during exposure.
Unknown authors · 1996
The study examined the effects of extremely low frequency magnetic fields on cell growth and c-myc mRNA expression in Chinese hamster ovary cells. The study tested a 5 mT, 60 Hz magnetic field. The exposure system consisted of a CO2 incubator with built-in Helmholtz coils (250 mm inner diameter, 160 mm distance, 128 turns), a slide regulator, and a thermocontroller. No significant difference was found in growth rate or c-myc expression between cells exposed to the magnetic field, sham-exposed cells, and cells in a conventional incubator.
Unknown authors · 1996
Researchers treated cultured mammalian cells with three carcinogens that produce DNA single-strand breaks. The repair rate of these lesions was unchanged by 50 Hz electric, magnetic, or combined fields across a range of intensities.
Unknown authors · 1996
The researchers investigated whether 60-Hz magnetic fields act at the cellular level to produce gene expression changes that can result in neoplastic transformation. Twenty-four hour exposure to 200 microT continuous magnetic fields produced negative results in Syrian hamster embryo cells and C3H/10T1/2 murine fibroblasts, with or without a chemical promoter. Extensive coded and uncoded analyses found no magnetic field effect on gene expression in human HL60 cells. No MF-induced changes in ornithine decarboxylase expression were observed in C3H/10T1/2 cells under the same exposure conditions.
Unknown authors · 1996
The study investigated the combined effects of 954 MHz microwaves and the DNA damaging agent mitomycin C. Whole blood samples were exposed in vitro to a 954 MHz emitting antenna from a GSM base station. Lymphocytes were then cultivated in the presence of mitomycin C. A highly reproducible synergistic effect was observed in sister chromatid exchange frequencies in metaphase figures.
