Unknown authors · 2003
Researchers exposed cultured fibroblasts from six healthy donors of different ages to intermittent ELF-EMF at 50 Hz and 1 mT for 1 to 24 hours. Basal DNA strand break levels correlated with donor age. The maximum DNA strand break response occurred at 15 to 19 hours of exposure. This response was more pronounced in cells from older donors, suggesting an age-related decrease in DNA repair efficiency.
Unknown authors · 2003
Unknown authors · 2003
Researchers exposed human immune cells to 60 Hz electromagnetic fields (like power lines) along with a known cancer-causing chemical called benzo(a)pyrene. They found that EMF exposure significantly increased genetic damage when combined with the chemical, compared to the chemical alone. The study suggests EMF may act as an amplifier of cancer-causing processes rather than directly causing cancer itself.
Unknown authors · 2003
Researchers studied 15 men chronically exposed to 50-Hz magnetic fields for 1–20 years and 15 unexposed controls. Exposure levels for the exposed group ranged from 0.1 to 2.6 μT weekly geometric mean. Blood samples were taken hourly from 2000 to 0800 and nighttime urine was also collected and analyzed. The study found no changes in plasma melatonin, urinary 6-sulfatoxymelatonin, or circadian rhythm in the exposed group.
Unknown authors · 2003
Researchers studied 15 men exposed to 50-Hz magnetic fields at work and home for 1-20 years, measuring their melatonin levels around the clock. Despite chronic exposure to fields up to 2.6 microTesla, the workers showed no changes in melatonin production or sleep hormone rhythms compared to unexposed controls. The findings challenge the theory that magnetic fields disrupt melatonin and cause health problems.
Unknown authors · 2003
Residential magnetic field exposure was calculated as a time-weighted average from 1967 until diagnosis using distance, line configuration, and current load, while occupational exposure was classified by an expert panel into three levels based on hours per week above background. The two highest residential exposure categories showed increased odds ratios for women (2.01 and 2.68) but not for men (1.70 and 1.37), and occupational exposure showed no significant association.
Unknown authors · 2003
This nested case-control study tested whether exposure to electromagnetic fields from high-voltage power lines increases hematological cancer incidence in adults. Residential time-weighted average magnetic fields were calculated from 1967 until diagnosis using cut-off points at 0.05 and 0.20 microT. The two highest residential exposure categories showed non-significant elevated odds ratios for all leukemia combined (OR 1.3, 95% CI 0.7-2.5 and OR 1.5, 95% CI 0.8-3.0). The increased risk was confined to chronic lymphocytic leukemia, acute lymphocytic and acute myeloid leukemia. Occupational exposure showed no significant association for any cancer site.
Unknown authors · 2003
Researchers isolated pineal glands from Wistar rats at 10:00 h and exposed them to a 50 Hz, 1 mT magnetic field for 4 hours in vitro. Basal melatonin release and enzyme activities were unchanged by magnetic field exposure alone. When magnetic field exposure preceded norepinephrine addition by 30 minutes, NAT activity, HIOMT activity, and melatonin release increased significantly. This effect did not occur when magnetic field and norepinephrine were applied together or in sonicated glands.
Unknown authors · 2003
Researchers exposed rat pineal glands to 50 Hz magnetic fields (the same frequency as power lines) and found the fields enhanced melatonin production when combined with norepinephrine stimulation. The magnetic fields didn't directly affect the melatonin-producing enzymes but instead altered the cellular signaling pathway that controls melatonin release.
Unknown authors · 2003
Higuchi Y et al. · 2002
Researchers performed a left-sided hemilaminectomy in adult Sprague-Dawley rats to expose the C6 dorsal root ganglion. Rats received pulsed radiofrequency, continuous radiofrequency, or sham treatment with the electrode on the ganglion for 120 seconds. Pulsed radiofrequency significantly increased cFOS-immunoreactive neurons in the superficial dorsal horn laminae three hours after treatment, while continuous radiofrequency did not. The authors concluded that pulsed radiofrequency activates pain-processing neurons in the dorsal horn without tissue heating.
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.
Unknown authors · 2002
Austrian researchers exposed human skin cells to 50 Hz electromagnetic fields (like power lines) for 24 hours and found that intermittent exposure caused significant DNA strand breaks, while continuous exposure did not. The study revealed that pulsed EMF exposure was more damaging than steady exposure, with the worst damage occurring during 5-minute on/10-minute off cycles.
Burch JB et al. · 2002
Researchers evaluated cellular telephone use and melatonin metabolite excretion in two groups of male electric utility workers. Participants collected urine samples and recorded telephone use over three workdays while personal magnetic field and light exposures were measured. In Study 1, no change in 6-OHMS excretion was observed with daily cellular telephone use over 25 minutes.
Unknown authors · 2002
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.
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.
Mueller CH, Krueger H, Schierz C · 2002
This double-blind laboratory experiment tested whether people can perceive a 50 Hz electric and magnetic field at 100 V/m and 6 μT, and whether self-reported electromagnetic hypersensitivity (EHS) is related to that ability. A total of 63 volunteers, 49 with self-reported EHS and 14 controls, each judged 10 sham and 10 exposed two-minute blocks in randomized order. Seven of the 63 subjects reached a statistically significant result, but there was no relevant difference between self-reported EHS subjects and controls in perception success rate or in the number and types of symptoms reported.
Unknown authors · 2002
Researchers exposed differentiating IMR-32 neuroblastoma cells to 60 Hz magnetic fields at 50, 100, and 200 microT for 4 hours. They measured APP695 mRNA levels using northern hybridization with Digoxygenin-labeled probes. The results provided no support for any relationship between APP695 gene transcription and either differentiation age or magnetic field exposure.
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.
Unknown authors · 2002
However, research reports indicate that living cells may respond to power-frequency fields well below the thermal noise limits. The study proposes that published thermal arguments may not fully account for all membrane force fields of thermal origin, and that a full accounting could show smaller net thermal noise fields in the power-frequency range.
Unknown authors · 2002
This 2002 theoretical study challenged the widely accepted belief that thermal noise in cell membranes would prevent power frequency electric and magnetic fields from affecting human cells. The researchers argued that previous thermal noise calculations were incomplete and that when all thermal forces are properly accounted for, the actual noise may be lower than thought, potentially allowing environmental EMF to influence cellular membranes.
Liu Y, Weng E, Zhang Y, Hong R. · 2002
Researchers exposed mice to a 50 Hz sinusoidal electromagnetic field at 0.2 mT or 6.0 mT for 2 weeks, and measured markers of the antioxidant system and cell membrane fluidity in brain and liver tissue. Malondialdehyde content in brain and liver increased with exposure, while total antioxidant capability decreased at both field strengths. When electromagnetic field exposure was combined with lead, the researchers observed synergic effects on lipid peroxidation.
Unknown authors · 2002
Female Sprague Dawley rats were MF or sham exposed for 2 weeks at a flux density of 100 microTesla. Proliferation of epithelial cells in the mammary tissue and adjacent skin was examined by in vivo labeling with bromodeoxyuridine (BrdUrd) and in situ labeling of Ki-67 protein by the antibody MIB-5. MF exposure significantly enhanced BrdUrd and Ki-67 labeling in the mammary epithelium, indicating a marked increase in cell proliferation. Melatonin levels in pineal or mammary glands were not affected by MF exposure. Topical application of 12-O-tetradecanoylphorbol-13-acetate increased BrdUrd and Ki-67 labeling in skin epithelial cells, particularly hair follicles, but not in mammary tissue.
Unknown authors · 2002
German researchers exposed female rats to 50 Hz magnetic fields at 100 microTesla (similar to power lines) for two weeks and found significantly increased cell division in mammary gland tissue. The study challenges the popular "melatonin hypothesis" by showing breast tissue effects occurred without changes in melatonin levels. This provides direct evidence that magnetic field exposure can stimulate breast cell proliferation, potentially explaining increased cancer risk.
