Unknown authors · 1994
Two pulse waveforms were tested, with rise and fall times of 85 microseconds (PMF-A) or 2.1 microseconds (PMF-B). After exposure, the eggs incubated for nine more days without fields, then embryos were examined blind. Both exposed groups had more developmental anomalies than controls, but only the PMF-B group showed a statistically significant increase (P=0.007) and a high rate of early embryonic death, while the PMF-A group's increase was not significant (P=0.173).
Unknown authors · 1994
Researchers exposed SV40-transformed human fibroblasts to a 60 Hz continuous-wave sinusoidal electromagnetic field. Exposure resulted in increased levels of virally derived mRNA and protein of large T-antigen. The findings provide evidence that foreign DNA integrated into cells can be affected by EM fields under conditions known to cause increased transcripts from endogenous cellular genes.
Unknown authors · 1993
Unknown authors · 1993
Unknown authors · 1993
DMBA was given orally at 5 mg/kg on the first day and weekly thereafter up to a total dose of 20 mg per rat. Eight weeks after DMBA application, the magnetic-field-exposed rats exhibited significantly more tumors than sham-exposed animals. At the end of the three-month exposure, tumor incidence in the exposed group was 50% higher than in the sham group, a statistically significant difference. Tumor size as estimated by palpation was also significantly larger in the magnetic-field-exposed rats compared with sham-exposed rats.
Unknown authors · 1993
Researchers conducted a telephone interview survey in November 1987 to assess depressive symptoms and headaches in relation to proximity to an alternating-current transmission line. Proximity was defined as residing on a property abutting the right-of-way or being able to see the towers from one's house or yard. Proximity was positively associated with depressive symptoms with an odds ratio of 2.8 (95% CI 1.6-5.1). The association was not explained by demographic variables associated with depression or by attitudes about power lines or other environmental issues. Nonmigraine headaches had a weaker association with proximity (odds ratio = 1.5, 95% CI 0.76-2.8) and self-reported migraine headaches exhibited no association (odds ratio = 0.99, 95% CI 0.29-3.4).
Unknown authors · 1993
Researchers exposed growing Escherichia coli strain AB1157 to a 1 Hz field at 1 or 3 kV/m and found no effect on spontaneous or UV-induced mutation frequencies to rifampicin resistance. Growth in the presence of charge did not alter the UV sensitivity of strains AB1157, TK702 umuC, or TK501 umuC uvrB. Although plasmid pKM101 increased UV resistance in repair-deficient strains, pre-growth in electric fields did not further increase UV resistance, and low frequency fields did not affect mitomycin C-induced mutation frequencies.
Unknown authors · 1993
Researchers measured intracellular calcium concentration in mouse lymphocytes using a fluorescent probe during a 60-minute exposure to cyclotron resonance conditions for calcium ions. They tested resonance conditions at 16 Hz and 50 Hz with DC field amplitudes shifting the frequency up to 25 percent either side of the calculated optimum. Concanavalin A treatment increased intracellular calcium significantly, but no change was detected under any magnetic field combination tested.
Unknown authors · 1993
The review discusses evidence of direct and indirect genetic toxicity effects for electric and magnetic fields at 50- and 60-Hz and miscellaneous pulsed exposures. Epidemiologic studies have reported a modestly increased risk of childhood leukemia associated with certain electric power wire configurations. Exposure conditions vary greatly among different end points measured, making comparisons and conclusions among experiments difficult. Most available evidence does not suggest that electric and/or magnetic fields cause DNA damage. Some positive findings and limitations in the studies suggest a need for additional work.
Unknown authors · 1992
Researchers used a nuclear run-off assay to measure specific gene transcription in CEM-CM3 T-lymphoblastoid cells exposed to a 1 gauss, 60 Hz sinusoidal magnetic field for 15 to 120 minutes. They observed time-dependent and cell density-dependent changes in the transcription of c-fos, c-jun, c-myc, and protein kinase C beta-form. Slot-blot analysis showed that changes in transcript levels paralleled the changes in gene transcription.
Unknown authors · 1992
Researchers exposed human immune cells to 60 Hz magnetic fields at 1 gauss (similar to power line levels) for 15-120 minutes and found significant changes in gene activity. Four important genes involved in cell growth and signaling showed altered transcription patterns that varied with exposure time and cell density. This demonstrates that even brief exposure to common power line frequencies can directly affect how genes function in human cells.
Unknown authors · 1991
T.T. · 1990
Researchers reviewed biological effects of static magnetic fields and found no specific target organ for deleterious effects at present. A documented effect is the induction of electrical potentials in major arteries during exposure, with 60 mT producing a 1 mV potential in the human aorta. Pacemaker reed switches can close at 1.7 mT, so wearers should be excluded from fields exceeding 1.0 mT.
Unknown authors · 1989
Researchers conducted a population-based case-control study of leukemia and residential proximity to electricity supply equipment in south-east England. The study included 771 leukemia cases matched to 1,432 cancer controls and 231 general population controls. Exposure to power-frequency magnetic fields was assessed indirectly from the distance, type, and loading of nearby power lines and transformer substations. Only 0.6% of subjects lived within 100 m of an overhead power line, where the relative risk of leukemia was 1.45 (95% CI 0.54-3.88), rising to 2.0 within 50 m (95% CI 0.4-9.0). Over 40% of subjects lived within 100 m of a substation, with a relative risk of 0.99, and residence within 25 m carried a risk of 1.3 (95% CI 0.8-2.0).
Unknown authors · 1989
Indira Nair, M. Granger Morgan, H. Keith Florig · 1989
Unknown authors · 1988
Researchers studied 356 children diagnosed with cancer between 1976 and 1983 in the Denver area and compared them with controls selected by random digit dialing. Measured magnetic fields under low power use at a 2.0 milligauss cutoff showed an odds ratio of 1.4 for total cancers, with higher odds ratios for leukemias, lymphomas, and soft tissue sarcomas. Wire configuration codes contrasting very high and high versus very low, low, and buried codes yielded an odds ratio of 1.5 for total cancers. Adjusted estimates for measured fields and wire codes did not differ from crude results, indicating an absence of confounding.
Unknown authors · 1987
Researchers exposed chick embryos to sinusoidally oscillating 50 Hz magnetic fields during their first two days of development. In the first series, abnormal embryo percentages were 16% in controls, 16% at 0.1 A/m, 14% at 0.3 A/m, 29% at 1 A/m, and 32% at 10 A/m. In the second series, abnormal embryo percentages were 17% in controls, 10% at 0.4 A/m, 19% at 0.6 A/m, 17% at 0.9 A/m, and 36% at 1.35 A/m. Only the 1.35 A/m group was significantly different from controls in the second series. The results suggest that exposure causes abnormal development and that no abnormalities are induced below a threshold between 0.9 and 1 A/m.
Unknown authors · 1986
M. Granger Morgan · 1986
Government agencies invested heavily in research examining whether 60-hertz electromagnetic fields from power lines pose health risks. The research demonstrated that low-frequency fields can produce changes in living systems under specific circumstances but has not demonstrated that a hazard exists. Laboratory animal screening studies largely failed to find adverse health impacts, and epidemiological studies linking long-term exposure to cancers were inconclusive. The scientific evidence neither clearly indicates a significant risk nor clearly indicates little or no risk from 60-hertz field exposures.
Unknown authors · 1984
Unknown authors · 1984
T. F. Budinger · 1981
The document revises previous NMR instrumentation and clinical study guidelines based on new information and reanalysis. For static magnetic fields, harmful physiological or genetic effects are not expected below 2 T. For changing magnetic fields, the induced current effect threshold is above 5 mT at 1-100 Hz, though waveform, repetition rate, maximum B field, and exposure duration need further study. RF heating guidelines set a practical upper limit of a few watts for short studies under 10 minutes and 1 W/kg for long-term studies, with power absorption estimated via RF coil Q measurements.
T. S. Tenforde · 1980
T. S. Tenforde, C. G. Dols, A. A. Lake, R. D. Hay · 1979
