Unknown authors · 2001
Researchers conducted a population-based case-control study across former West Germany. They measured 24-hour residential magnetic fields for 514 children with acute leukemia and 1,301 control children. Childhood leukemia and 24-hour median magnetic fields showed only a weak relationship. However, a significant association emerged for magnetic field exposure during the night.
Unknown authors · 2001
Each woman provided data over a 72-hour period in two different seasons, including bedroom magnetic field and ambient light measured every 30 seconds, personal magnetic field measured at 30-second intervals, and complete nighttime urine samples on three consecutive nights. Lower nocturnal urinary 6-sulfatoxymelatonin levels were associated with more hours of daylight, older age, higher body mass index, current alcohol consumption, and current use of beta blockers, calcium channel blockers, or psychotropics. After adjusting for these factors, higher bedroom magnetic field levels were associated with significantly lower urinary 6-sulfatoxymelatonin concentration during the same night, primarily in women using those medications and during times of year with the fewest hours of darkness.
Unknown authors · 2001
Researchers measured magnetic fields and melatonin levels in 203 women's bedrooms over 72-hour periods across different seasons. They found that higher bedroom magnetic field levels were associated with significantly lower nighttime melatonin production, particularly in women taking certain medications. This suggests that common household magnetic fields can disrupt the body's natural sleep hormone production.
Unknown authors · 2001
Researchers independently replicated a study testing whether a 1.2 microT, 60 Hz magnetic field alters the effects of melatonin and tamoxifen on MCF-7 human breast cancer cells. In the melatonin experiment, repeated three times, melatonin reduced cell numbers by 16.7% after seven days, but this reduction disappeared when cells were exposed to the magnetic field. In the tamoxifen experiment, repeated nine times, tamoxifen reduced cell growth by 18.6% and 25% on days six and seven without the field, but only by 8.7% and 13.1% with the field. The results were consistent with the original findings of Harland and Liburdy.
Unknown authors · 2001
EPA researchers tested whether 60 Hz magnetic fields at 1.2 microT could interfere with melatonin and tamoxifen's ability to inhibit breast cancer cell growth. They found that magnetic field exposure completely blocked melatonin's cancer-fighting effects and significantly reduced tamoxifen's effectiveness. This suggests power line frequency EMF may interfere with the body's natural cancer protection mechanisms.
Lyskov E, Sandström M, Mild KH · 2001
Researchers investigated possible neurophysiological effects of an intermittent 15 sec on/off cycle, 60 Hz, 10 μT magnetic field on patients with perceived electromagnetic hypersensitivity (EHS) and control subjects during rest and a mental arithmetic task. Magnetic field exposure did not affect autonomic system or electroencephalographic variables in either group. EHS patients and controls showed significant differences in heart rate, heart rate spectrum ratio, and electrodermal activity, while EEG characteristics did not differ between groups.
Unknown authors · 2001
Unknown authors · 2001
Japanese researchers exposed breast cancer cells to 50 Hz magnetic fields at extremely low levels (1.2 microT and 100 microT) and found these fields disrupted melatonin's cancer-fighting signals. The magnetic fields prevented melatonin from properly inhibiting cellular pathways that normally help control cancer cell growth.
Unknown authors · 2001
Researchers demonstrated that a 50- to 60-Hz magnetic field interacts with cell differentiation through two opposing mechanisms. The field antagonizes the shift in cell membrane surface charges during early differentiation and modulates hyperpolarizing K channels by increasing intracellular calcium. The simultaneous onset of both mechanisms prevents alterations in cell differentiation. The authors propose that cells are normally protected against electromagnetic insult.
Unknown authors · 2001
Researchers induced dopamine neuron damage in newborn rats by infusing 6-OHDA into the brain ventricles on postnatal day 3. At two months of age, the rats were exposed to a 10 Hz, 1.8–3.8 mT magnetic field for one hour daily over 14 days, while a sham-exposed group had the solenoid turned off. After exposure, magnetic-field-exposed rats with dopamine damage showed reduced irritability and oral activity when given a D1 receptor agonist and increased catalepsy when given a D1 receptor antagonist. The authors concluded that extremely low frequency magnetic fields reduce the reactivity of central dopamine D1 receptors.
Unknown authors · 2001
Researchers examined responses of the small heat shock protein gene hsp-16 in transgenic Caenorhabditis elegans exposed to electromagnetic fields. Expression of the hsp-16-lacZ gene was enhanced when transgenic animals were exposed to magnetic fields up to 0.5 T at 60 Hz. The hsp-16 promoter was more efficiently expressed at the embryonic than at the post-embryonic stage irrespective of exposure. Promoter activity was more sensitive to the stimulus in the intestine at the post-embryonic stage.
Unknown authors · 2001
Unknown authors · 2001
German researchers exposed Syrian hamster embryo cells to 50 Hz magnetic fields (the same frequency as power lines) combined with known cancer-causing chemicals. They found that magnetic field exposure increased genetic damage by 80% when combined with the carcinogen benzo(a)pyrene. This suggests power line frequency fields may act as co-carcinogens, enhancing the effects of other cancer-causing agents.
Unknown authors · 2001
The study examined 30 human volunteers. Volunteers were exposed to a 28 microT circularly polarized 50 Hz magnetic field for 50 minutes in a double-blind crossover design. The majority of cognitive measures showed no significant effect of exposure. Verbal recall of a 15-word list after interference was significantly impaired during field exposure. Performance on a trail-making task requiring executive functioning also decreased with exposure.
Unknown authors · 2001
Australian researchers tested 30 volunteers exposed to 28 microT 50 Hz magnetic fields (similar to occupational levels) for 50 minutes while performing cognitive tests. The study found significant impairment in short-term memory for word recall and decreased performance on executive functioning tasks requiring working memory. These findings suggest power frequency magnetic fields may affect specific brain functions related to learning and mental processing.
Unknown authors · 2001
The study examined the effect of a sinusoidal 50 Hz magnetic field on preimplantation CBA/S mouse embryos in vitro. Embryos were exposed to a field of 10 A/m rms corresponding to 13 microT rms while cultured at 37°C in a CO2 incubator. Vitality and developmental stages were similar between groups, though slightly more dead embryos appeared on day 1 in the exposed group (P<0.05) and development was slightly impaired. The authors concluded that the exposure did not significantly disturb development up to the blastocyst stage.
Fernie KJ, Bird DM. · 2001
Researchers investigated whether exposure to magnetic and electric fields similar to those from power lines induces an immune response and alters oxidative stress levels in American kestrels. Captive male kestrels were bred under control or EMF conditions equivalent to those experienced by wild kestrels. Short-term EMF exposure suppressed plasma total proteins, hematocrits, and carotenoids in the first half of the breeding season, and also suppressed erythrocyte cells and lymphocyte proportions while elevating granulosa proportions at the end of the breeding season. Long-term EMF exposure may be linked to higher levels of oxidative stress through EMF exposure only, and also suppressed hematocrits in the first half of the reproductive period.
Jajte J, Zmyślony M, Palus J, Dziubałtowska E, Rajkowska E. · 2001
Researchers used the alkaline comet assay to assess DNA damage in rat peripheral blood lymphocytes exposed in vitro to iron ions and a 50 Hz magnetic field. Cell samples were incubated for 3 hours in Helmholtz coils at 7 mT 50 Hz, and some were treated with ferrous chloride at 10 μg/ml during that exposure. A significant increase in cells with DNA damage was found only after simultaneous exposure to ferrous chloride and the 7 mT 50 Hz magnetic field, compared to control samples or those incubated with ferrous chloride alone. When cells were treated with melatonin before that combined exposure, the number of damaged cells was significantly reduced, with the reduction reaching about 50% at 0.5 mM and about 100% at 1.0 mM.
Simkó M, Droste S, Kriehuber R, Weiss DG · 2001
Researchers examined the effects of 50 Hz electromagnetic fields on phagocytosis and free radical production in mouse bone marrow-derived macrophages exposed in vitro to magnetic field densities of 0.5 to 1.5 mT. Short-time exposure of 45 minutes resulted in a significantly increased phagocytic uptake of 36.3% plus or minus 15.1%, as measured by the internalization rate of latex beads. A significant increase in superoxide production was also detected after exposure to electromagnetic fields. Because co-exposure to electromagnetic fields and TPA showed no additive increase in bead uptake, researchers concluded that the electromagnetic fields-induced stimulation does not involve the protein kinase C signal transduction pathway.
Unknown authors · 2000
Researchers conducted a pooled analysis based on individual records from nine studies. The analysis included 3203 children with leukaemia and 10 338 control children with estimated residential magnetic field exposures levels < 0.4 μT, and 44 children with leukaemia and 62 control children with exposures ≥ 0.4 μT. For exposures ≥ 0.4 μT the estimated summary relative risk was 2.00 (1.27–3.13), P value = 0.002, while for exposures < 0.4 μT risk estimates were near the no effect level. Adjustment for potential confounding variables did not appreciably change the results. No evidence was found for a wire-code paradox; the highest wire code category showed a relative risk of 1.24 (0.82–1.87).
Unknown authors · 2000
Researchers incubated isolated rat lymphocytes for three hours in 7 mT static or 50 Hz magnetic fields, with some samples receiving iron chloride or hydrogen peroxide. Magnetic field exposure alone did not increase DNA damage in the comet assay. Iron chloride alone also did not produce detectable DNA damage. However, combined exposure to iron chloride and magnetic fields significantly increased damaged cells to about 20 percent for static fields and 15 percent for 50 Hz fields. Control samples showed about 97 percent of cells without DNA damage.
Unknown authors · 2000
The researcher studied the incidence of central nervous system diseases in 30,631 persons employed in Danish utility companies between 1900 and 1993, linked the cohort to the Danish National Register of Patients and compared cases from 1978 to 1993 with general population rates, and fitted a multiplicative Poisson regression model to estimated 50-Hz electromagnetic field exposure levels. Overall there was an increase in risk for senile dementia and motor neuron diseases combined, while Parkinson disease, Alzheimer disease, and other central nervous system diseases were essentially unrelated to exposure. A decreased risk of epilepsy compared with the general population probably reflects a healthy worker effect, but internal comparisons showed an increased risk of epilepsy.
Unknown authors · 2000
Researchers measured personal magnetic field exposure, ambient light, and excretion of the melatonin metabolite 6-hydroxymelatonin sulfate over three consecutive workdays in electric utility workers. Men working more than two hours daily in substation and three-phase environments showed a magnetic field-dependent reduction in adjusted mean nocturnal and post-work metabolite levels, while those working two hours or less showed no effect. No changes were observed in men working in single-phase environments.
Unknown authors · 2000
Researchers measured melatonin levels in electric utility workers exposed to 60-Hz magnetic fields from substations and 3-phase power lines. Workers with more than 2 hours daily exposure showed significantly reduced melatonin production, while those with shorter exposures showed no effect. This suggests that power frequency magnetic fields can disrupt the body's natural sleep hormone production.
Unknown authors · 2000
Researchers cultured mouse pre-antral follicles for 5 days and exposed them to pulsed ELF-EMF at 33 Hz or 50 Hz. ELF-EMF did not affect follicular growth over 3 days, but on day 5 the 33 Hz exposure significantly reduced growth compared to controls, while 50 Hz did not. ELF-EMF severely impaired antrum formation at both frequencies, with control follicles forming antral cavities at 79% versus 30% at 33 Hz and 51.6% at 50 Hz. Oocytes from exposed follicles showed a reduced ability to resume meiotic maturation compared to controls.
