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At least 379 records · Page 21Linked to original sources
PubMed1989

The conservative treatment of osteonecrosis of the femoral head. A comparison of core decompression and pulsing electromagnetic fields.

Once roentgenographic changes are apparent, osteonecrosis of the femoral head in the adult generally progresses to osteoarthritis within two to three years. A variety of conservative surgical procedures have been devised to conserve the femoral head with varying success. This study examines the effectiveness of pulsing electromagnetic fields and core decompression in the treatment of osteonecrosis of the femoral head. Both techniques reduce the incidence of clinical and roentgenographic progression. Exposure to pulsing electromagnetic fields appears to be more effective in hips with Ficat II lesions than in hips with more advanced lesions.

Adult↗
PubMed1994

Frequency-specific blocking in the human brain caused by electromagnetic fields.

Based on preliminary observations that continuous exposure to electromagnetic fields (EMFs) produced an after-effect on human brain electrical activity, the effect of 10 Hz, 1 gauss, on the intrinsic activity of the brain at that frequency was studied. Ten subjects were exposed for 10 min and the 10 Hz spectral power was measured during the 1 min interval following stimulation and compared with control values obtained from the same subjects. Significantly reduced brain electrical activity from the occipital electrodes following termination of the EMF exposure was observed, thereby confirming the preliminary results.

Adult↗
PubMed1992

The effects of pulsed electromagnetic fields on blood vessel growth in the rabbit ear chamber.

A double-blind, controlled trial of the effects of pulsed electromagnetic fields on capillary growth in the rabbit ear chamber in adult New Zealand white rabbits has been performed. Three waveforms have been investigated. The first, a pulse burst waveform, produced a significant increase in the rate of growth of the vascular tissue within the chamber, but had no effect on macroscopic tissue maturation. The second and third, two different single pulse waveforms, had, in contrast, no significant effect on the rate of vascular growth and only an effect on vessel characteristics, with increased maturation of vessels using the second waveform. It is concluded that some of the observed effects of pulsed electromagnetic fields on tissue healing may be mediated through a primary effect on vascular growth.

Animals↗
PubMed2003

Effects of electromagnetic fields on proteoglycan metabolism of bovine articular cartilage explants.

Electromagnetic field (EMF) exposure has been proposed for the treatment of osteoarthritis. In this study, we investigated the effects of EMF (75 Hz, 2,3 mT) on proteoglycan (PG) metabolism of bovine articular cartilage explants cultured in vitro, both under basal conditions and in the presence of interleukin-1beta (IL-1beta) in the culture medium. Proteoglycan synthesis and the residual PG tissue content resulted significantly higher in EMF-exposed explants than in controls, whereas no effect was observed on PG release and nitric oxide (NO) production. IL-1beta induced both a reduction in PG synthesis and an increase in PG release, related to a strong stimulation of NO production, which resulted in a net loss of tissue PG content. In IL-1beta-treated explants, EMF increased PG synthesis, whereas in spite of a slight stimulation of NO production EMF did not modify PG release. This resulted in the residual PG tissue content being maintained at the control level. In both experimental conditions, the effects of EMF were associated with an increase in lactate production. The results of our study show that EMFs are able to promote anabolic activities and PG synthesis in bovine articular cartilage explants. This effect also is maintained in the presence of IL-1beta, thus counteracting the catabolic activity of the cytokine. Altogether, these data suggest that EMF exposure exerts a chondroprotective effect on articular cartilage in vitro.

Animals↗
PubMed2003

[Environment protection against electromagnetic fields. Legal point of view].

The author presents a concise information on the formal and legal status of the protection against the effect of electromagnetic fields in humans adopted in the European Union member states. Essential information on the Polish legal basis of the environmental protection against the effect of electromagnetic fields is provided. The most important, in the author's opinion, provisions of the Environmental Protection Law and executory provisions are discussed.

Dose-Response Relationship, Radiation↗
PubMedDate not supplied

Study of human neurovegetative and hematologic effects of environmental low-frequency (50-Hz) electromagnetic fields produced by transformers.

A survey of neurovegetative and hematologic disorders was conducted in a population (n = 13) exposed occupationally to environmental electromagnetic fields; the population was matched with 13 control subjects. The exposed subjects worked at least 8 h/d for 1-5 y in premises located above transformers and high-tension cables, and the subjects were submitted to low-frequency electromagnetic fields (i.e., 50 Hz) of 0.2 microT-6.6 microT. The subjects were matched with respect to socioeconomic category, sex, and age with a control population of subjects that worked in premises outside of the immediate vicinity of transformers or high-tension cables. The exposed population had a significant increase in degree of certain neurovegetative disorders (i.e., physical fatigue, psychical asthenia, lipothymia, decreased libido, melancholy, depressive tendency, and irritability). In addition, the population experienced a significant fall in total lymphocytes and CD4, CD3, and CD2 lymphocytes, as well as a rise in NK cells. Leukopenia and neutropenia were also observed in two persons permanently exposed to doses of 1.2-6.6 microT. The disorders disappeared when exposure stopped, and they reappeared on reexposure.

Adult↗
PubMed1999

Exposure of the critically ill patient to extremely low-frequency electromagnetic fields in the intensive care environment.

OBJECTIVE: To measure the electromagnetic emission of intensive care medical equipment, in order to assess whether a potentially dangerous magnetic flux is present around the patient, and to evaluate the exposure conditions of the patient to extremely-low-frequency electromagnetic fields (ELF EMF). DESIGN: Descriptive study. SETTING: Intensive care unit (ICU) at a general hospital. MEASUREMENT AND RESULTS: The flux density of alternating (AC) 50-H2, EMF was measured and mapped around electrical devices in a six-beds adult ICU furnished with standard equipment (ventilator, monitor, infusion pumps, heated airbed, humidifier). The overall flux density in the patient area was assessed by measuring the field intensity at the patient's head during the day and at night over 6 days. The magnetic flux density was not uniformly distributed around each device, being higher [up to 40 microTesla (microT)] close to fan motors and mains supply. In 83 % of the patients a field intensity > 0.20 microT (safety limit) was detected. CONCLUSIONS: The ICU environment is at risk from electromagnetic pollution, the long-term stay of chronic patients and their "day-long" exposure are additional risk factors. EMFs drop off as the distance from the equipment is increased, according to the inverse-square law, and the exposure risk may be minimized by keeping a safety distance from the EMF source. The actual value of that safety distance may be variable and depends on several factors: (1) type of equipment, (2) orientation of equipment, (3) equipment "overcrowding" and (4) available space in each bed space. The magnetic flux density should be monitored regularly in every ICU for the specific design of each unit.

Aged↗
PubMed2001

Chromosomal aberrations in lymphocytes of employees in transformer and generator production exposed to electromagnetic fields and mineral oil.

The objective was to study the risk of cytogenetic damage among high voltage laboratory workers exposed to electromagnetic fields and mineral oil. This is a cross sectional study of 24 exposed and 24 matched controls in a Norwegian transformer factory. The exposure group included employees in the high voltage laboratory and in the generator soldering department. Electric and magnetic fields and oil mist and vapor were measured. Blood samples were analyzed for chromosomal aberrations in cultured lymphocytes. In addition to conventional cultures, the lymphocytes were also treated with hydroxyurea and caffeine. This procedure inhibits DNA synthesis and repair in vitro, revealing in vivo genotoxic lesions that are repaired during conventional culturing. In conventional cultures, the exposure group and the controls showed similar values for all cytogenetic parameters. In the DNA synthesis- and repair-inhibited cultures, generator welders showed no differences compared to controls. Among high voltage laboratory testers, compared to the controls, the median number of chromatid breaks was doubled (5 vs. 2.5 per 50 cells; P<0.05) the median number of chromosome breaks was 2 vs. 0.5 (P>0.05) and the median number of aberrant cells was 5 vs. 3.5 (P<0.05). Further analysis of the inhibited culture data from this and a previous study indicated that years of exposure and smoking increase the risk of aberrations. We conclude that there was no increase in cytogenetic damage among exposed workers compared to controls in the conventional lymphocyte assay. In inhibited cultures, however, there were indications that electromagnetic fields in combination with mineral oil exposure may produce chromosomal aberrations.

Adult↗
PubMed1996

Regulation of c-fos is affected by electromagnetic fields.

The goal of the present study was to determine if regulatory regions of the c-fos gene were responsive to electromagnetic field exposure. The research design used transfected cells to increase the sensitivity of assays designed to identify changes following exposure. HeLa cells were transiently transfected with plasmids containing upstream regulating regions of c-fos up to -700 base pairs, coupled with the prokaryotic reporter gene CAT. Cells were exposed to an environmentally relevant EMF of 60 Hz at 60 mGrms. CAT expression above control levels in transfected cells (region +42 to -700 bp) was observed following 5 min exposure to the electromagnetic field, with a peak at 20 min. The expression was at basal levels following 40 min exposure. Deletion analysis of upstream DNA narrowed the responsive region to 138 base pairs from -363 to -225, which contains the SRE/AP-1 sites.

Electromagnetic Fields↗
PubMed2003

Effects of different intensities of extremely low frequency pulsed electromagnetic fields on formation of osteoclast-like cells.

Over the past 30 years, the beneficial therapeutic effects of selected low energy, time varying electromagnetic fields (EMF) have been documented with increasing frequency to treat therapeutically resistant problems of the musculoskeletal system. However, the underlying mechanisms at a cellular level are still not completely understood. In this study, the effects of extremely low frequency pulsed electromagnetic fields (ELF-PEMF) on osteoclastogenesis, cultured from murine bone marrow cells and stimulated by 1,25(OH)(2)D(3), were examined. Primary bone marrow cells were cultured from mature Wistar rats and exposed to ELF-PEMF stimulation daily for 7 days with different intensities of induced electric field (4.8, 8.7, and 12.2 micro V/cm rms) and stimulation times (0.5, 2, and 8 h/day). Recruitment and authentication of osteoclast-like cells were evaluated, respectively, by determining multinuclear, tartrate resistant acid phosphatase (TRAP) positive cells on day 8 of culture and by the pit formation assay. During the experiments, cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin 1-beta (IL-1beta), and prostaglandin-E(2) (PGE(2)) were assayed using the enzyme linked immunosorbent assay (ELISA). These findings suggest that ELF-PEMF can both enhance (approximately 50%) and suppress (approximately 27%) the formation of osteoclast-like cells in bone marrow culture, depending on the induced electric field intensity. In addition, consistent correlations were observed between TNF-alpha, IL-1beta, and osteoclast-like cell number after exposure to different induced electric field intensities of ELF-PEMF. This in vitro study could be considered as groundwork for in vivo ELF-PEMF clinical applications on some osteoclast-associated bone diseases.

Animals↗
PubMed1999

Absenteeism and mortality of workers exposed to electromagnetic fields in the French Electricity Company.

The objective of this study was to describe the health status of electricity workers exposed to electromagnetic fields during their job. Two groups of exposed workers were studied from 1978 to 1993: the live line workers (n = 121) and the substation workers (n = 232.7) of the French Electricity Company (EDF). A control group was randomly selected from all the company non-management male employees; one control for each exposed subject was matched for the first year of employment. Absenteeism indices and mortality rates were computed and compared in the exposed and control groups. The absence rates were 1.98% in the substation workers and 2.5% in the control group (p < 0.001) and 2.7% in the live-line workers and 2.8% in the control group (NS). No effect of the length of exposure was found. However the medical causes of sickness absence were different: exposed employees had less psychiatric and respiratory diseases but more accidents at work than their control group. Relative risks of accidents at work were 1.2 95% confidence interval (CI) = 1.08-1.33[ for substation workers and 3.22 (CI = 1.78-5.88) for live line workers. EDF electromagnetic field exposed workers seemed not to be affected by any specific health problems except for an excess of accidents at work.

Absenteeism↗
PubMed2002

Mechanism for action of electromagnetic fields on cells.

A biophysical model for the action of oscillating electric fields on cells, presented by us before [Biochem. Biophys. Res. Commun. 272(3) (2000) 634-640], is extended now to include oscillating magnetic fields as well, extended to include the most active biological conditions, and also to explain why pulsed electromagnetic fields can be more active biologically than continuous ones. According to the present theory, the low frequency fields are the most bioactive ones. The basic mechanism is the forced-vibration of all the free ions on the surface of a cell's plasma membrane, caused by an external oscillating field. We have shown that this coherent vibration of electric charge is able to irregularly gate electrosensitive channels on the plasma membrane and thus cause disruption of the cell's electrochemical balance and function [Biochem. Biophys. Res. Commun. 272(3) (2000) 634-640]. It seems that this simple idea can be easily extended now and looks very likely to be able to give a realistic basis for the explanation of a wide range of electromagnetic field bioeffects.

Animals↗
PubMed1984

Pulsed electromagnetic fields increase the rate of rat liver regeneration after partial hepatectomy.

Pulsed extremely low-frequency electromagnetic fields interact with rat liver regeneration following partial hepatectomy when delivered to the rats immediately after the operation and every 12 hr thereafter. This interaction results first in an increased ornithine decarboxylase activity, an enzyme used as an early marker of cell growth. The rate of labeled thymidine incorporation into DNA is also increased by the treatments with magnetic fields during the early phases of liver regeneration. Glycogen depletion and lipid accumulation, two well-known early peculiar phenomena of liver regeneration following partial hepatectomy, are quantitatively decreased by the treatments with electromagnetic fields. The recovery to normal glycogen and lipid contents is completed within 5 days after surgery, instead of 7 days as found in control rats.

Animals↗
PubMed2003

Intermittent extremely low frequency electromagnetic fields cause DNA damage in a dose-dependent way.

OBJECTIVES: Epidemiological studies have reported an association between exposure to extremely low frequency electromagnetic fields (ELF-EMFs) and increased risk of cancerous diseases, albeit without dose-effect relationships. The validity of such findings can be corroborated only by demonstration of dose-dependent DNA-damaging effects of ELF-EMFs in cells of human origin in vitro. METHODS: Cultured human diploid fibroblasts were exposed to intermittent ELF electromagnetic fields. DNA damage was determined by alkaline and neutral comet assay. RESULTS: ELF-EMF exposure (50 Hz, sinusoidal, 1-24 h, 20-1,000 mu T, 5 min on/10 min off) induced dose-dependent and time-dependent DNA single-strand and double-strand breaks. Effects occurred at a magnetic flux density as low as 35 mu T, being well below proposed International Commission of Non-Ionising Radiation Protection (ICNIRP) guidelines. After termination of exposure the induced comet tail factors returned to normal within 9 h. CONCLUSION: The induced DNA damage is not based on thermal effects and arouses concern about environmental threshold limit values for ELF exposure.

Adult↗
PubMed2005

Electromagnetic fields from mobile phones do not affect the inner auditory system of Sprague-Dawley rats.

The auditory system is the first biological structure facing the electromagnetic fields emitted by mobile phones. The aim of this study was to evaluate the cochlear functionality of Sprague-Dawley rats exposed to electromagnetic fields at the typical frequencies of GSM mobile phones (900 and 1800 MHz) by distortion product otoacoustic emissions, which are a well-known indicator of the status of the cochlea's outer hair cells. A population of 48 rats was divided into exposed and sham-exposed groups. Three sets of four loop antennas, one for sham-exposed animals and two for exposed animals, were used for the local exposures. Rats were exposed 2 h/day, 5 days/week for 4 weeks at a local SAR of 2 W/kg in the ear. Distortion product otoacoustic emissions tests were carried out before, during and after the exposure. The analysis of the data shows no statistically significant differences between the audiological signals recorded for the different groups.

Animals↗
PubMed1988

[Reaction of the ultrastructure of the rat spinal ganglion to exposure to a pulsed electromagnetic field].

White noninbred male rats have been subjected to a total effect of the impulsive electromagnetic field (IEMF) of 100 mT for 1, 3, 5, 10 days, 15 min daily. IEMF produces an essential morphofunctional reorganization in neurons, gliocytes, blood vessels of the rat spinal ganglion. Light neurons demonstrate an earlier reaction. Manifestation of the ultrastructural changes depends on multiplicity of the IEMF action: at initial effects they concern predominantly cytoplasmic structures of the neurons, at multiple effects--nuclear structures also become involved, reactive changes in gliocytes appear and increase. Early and distinctly seen reaction to the IEMF effect demonstrates endothelium of blood vessels. The changes revealed in the spinal ganglion are reversible, but the time of restoration of the normal ultrastructure directly depends on multiplicity of the IEMF action.

Animals↗