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PubMed2005

The Bernal Lecture 2004 Are low-frequency electromagnetic fields a health hazard?

Electric power is an essential commodity of the developed world, and is critical to the continuing progress of our technology-based society, as well as to the growth of less privileged societies. In contrast to its overwhelming benefits, there is a suspicion that the magnetic component of the electromagnetic fields (EMFs) associated with power distribution and electrical appliances has adverse health effects, especially a small increased incidence of childhood leukaemia. The possibility that environmental EMFs represent a health hazard has serious economic implications for government, the electricity industry and society, as well as raising several profound scientific challenges, including, in particular, biophysical mechanisms, experimental replication and scientific uncertainty. These challenges are explored in relation to the experiences of the EMF Biological Research Trust, a UK medical research charity which funds basic research on the biological effects of extremely low-frequency electromagnetic fields (ELF-EMFs). As judged from these experiences, at the present time there is no compelling experimental evidence that environmental ELF-EMFs induce biological responses.

Biophysical Phenomena↗
PubMedDate not supplied

[Effect of low-frequency electromagnetic fields on the individual functional systems of the body].

This paper is a review of recent publications about the effects of low frequency electromagnetic fields (EMF) (constant and pulsed) on the cardiovascular, neuroendocrine, and blood systems of experimental animals and industrial workers exposed to them. It is reported that the regulatory systems (nervous and endocrine) are highly sensitive to EMF. It is obvious that investigations of hormone-receptor interactions can help better understand EMF effects on the endocrine system and the body as a whole. Published data about EMF effects on the cardiovascular system and blood are often contradictory, probably, because of different estimates of allowable limits recognized in various countries. It is hypothesized that circulatory changes are largely dependent on the central regulatory structures, particularly hypothalamus. White blood responses to the exposure, being most significant among hematological reactions, are also induced, to a certain extent, by regulatory mechanisms. The EMF effects may depend on the initial state and individual properties of the biological organism. It is postulated that the EMF effects on regulatory mechanisms may be related to primary disorders in cellular and mitochondrial membranes.

Animals↗
PubMed1989

Effect of low frequency low energy pulsing electromagnetic field (PEMF) on X-ray-irradiated mice.

C3H/Km flora-defined mice were used to investigate the effect of exposure to pulsing electromagnetic field (PEMF) after total body x-ray irradiation. Prolonged exposure to PEMF had no effect on normal nonirradiated mice. When mice irradiated with different doses of x-ray (8.5 Gy, 6.8 Gy, and 6.3 Gy) were exposed to PEMF 24 h a day, we observed a more rapid decline in white blood cells (WBC) in the peripheral blood of mice exposed to PEMF at all the x-ray dosages used. No effect of exposure to PEMF was observed on the survival of the mice irradiated with 6.3 Gy and 8.5 Gy; in mice irradiated with 6.8 Gy, 2 out of 12 survived when exposed to PEMF as compared to 10 out of 12 control mice that were irradiated only. At day 4 after irradiation autoradiographic studies performed on bone marrow and spleen of 8.5-Gy-irradiated mice showed no difference between controls and mice exposed to PEMF, whereas on 6.8-Gy mice the bone marrow labeling index was lower in mice exposed to PEMF. In mice irradiated to 6.3 Gy we observed that the recovery of WBC in the peripheral blood was slowed in mice exposed to PEMF and their body weight was significantly lower than in control mice that were irradiated only. The spleen and bone marrow of the mice irradiated to 6.3 Gy and sacrificed at days 4, 14, 20, and 25 after irradiation were analyzed by autoradiography to evaluate the labeling index. Half of the spleens from mice sacrificed at day 25 after irradiation were used to evaluate the RNA content. Autoradiography showed that in the spleen and bone marrow of control mice, there were more cells labeled with [3H]thymidine at days 4 and 14 and less at days 20 and 25 after irradiation in comparison with mice irradiated and exposed to PEMF. The Northern blot analysis of histone H3 and p53 protein RNAs extracted from the spleens at day 25 after irradiation showed a slight increase in cycling cells among spleens of mice exposed to PEMF. We suggest that the exposure to PEMF immediately after x-ray irradiation results in increased damage.

Animals↗
PubMed1981

Treatment of ununited tibial diaphyseal fractures with pulsing electromagnetic fields.

One hundred and twenty-five patients with one hundred and twenty-seven ununited fractures of the tibial diaphysis were treated exclusively with pulsing electromagnetic fields. The over-all success rate in healing of the fracture with this surgically non-invasive out-patient method was 87 per cent. The success rate was not materially affected by the age or sex of the patient, the length of prior disability, the number of previous failed operations, or the presence of infection or metal fixation.

Adolescent↗
PubMed2006

Theory of diatomic molecules in an external electromagnetic field from first quantum mechanical principles.

We study a general problem of the translational/rotational/vibrational/electronic dynamics of a diatomic molecule exposed to an interaction with an arbitrary external electromagnetic field. The theory developed in this paper is relevant to a variety of specific applications, such as alignment or orientation of molecules by lasers, trapping of ultracold molecules in optical traps, molecular optics and interferometry, rovibrational spectroscopy of molecules in the presence of intense laser light, or generation of high order harmonics from molecules. Starting from the first quantum mechanical principles, we derive an appropriate molecular Hamiltonian suitable for description of the center of mass, rotational, vibrational, and electronic molecular motions driven by the field within the electric dipole approximation. Consequently, the concept of the Born-Oppenheimer separation between the electronic and the nuclear degrees of freedom in the presence of an electromagnetic field is introduced. Special cases of the dc/ac-field limits are then discussed separately. Finally, we consider a perturbative regime of a weak dc/ac field, and obtain simple analytic formulas for the associated Born-Oppenheimer translational/rotational/vibrational molecular Hamiltonian.

Journal Article↗
PubMed1988

Degradative pathways in cultured synovial fibroblasts: selective effects of pulsed electromagnetic fields.

A cell culture model for studying the cytokine-mediated degradation of connective tissue was exposed to clinically applied, low-frequency pulsed electromagnetic fields (PEMF), and levels of collagenolytic activity, two lysosomal hydrolases, and prostaglandin E2 were measured. PEMFs reduced the release of two lysosomal enzymes by cultured rabbit synovial fibroblasts but did not affect their response to mononuclear-cell-conditioned medium. PEMF did not alter levels of cytokine activity produced by a mixed mononuclear cell population, nor did they affect the cytokine-mediated release of collagenase or prostaglandin E2 by synovial fibroblasts. The relevance of these findings to the clinical application of PEMF to soft- and hard-tissue injuries is discussed.

Acetylglucosaminidase↗
PubMed1997

[The action of a modulated electromagnetic field on the emotional component of the systemic organization of behavioral acts in rats].

Experimental findings are reviewed in respect to the effect of modulated electromagnetic field (MEMF) upon emotional responses of rats accompanying various phases of systemic organisation of their behaviour. Blocking effects of the MEMF are shown in simulated self-stimulation and various conditioned types of behaviour in rats. In author's opinion, the MEMF affect the informative component of behaviour: emotions.

Animals↗
PubMed1989

[The effect of a high-frequency electromagnetic field (2.45 GHz) on perceptual processes, psychological performance and well-being].

In a sample of 8 male subjects the effect of an ultra-highfrequency electromagnetic field (f = 2.45 GHz) with power densities of 1,000, 500 and 100 microW/cm2 was investigated. As parameters were used the perceptional threshold in a tachistoscopic perceptional test, the total time from the numbersearch-test and the sum of acute symptoms and complaints measured by a special questionnaire. At the highest field intensity on the one side increases of the total times and of the sum of complaints occurred. The differential threshold increased distinctly under 500 microW/cm2 exposure, whereas the total times and the sum of symptoms were not affected. At the lowest power density no differences between exposure and nonexposure conditions have been found. The intraindividual variability was considerable.

Adult↗
PubMed1999

Microelectronic sensors for measurement of electromagnetic fields of living cells and experimental results.

Microelectronic sensors are used for measurements of electromagnetic fields generated by synchronized cultures of yeast cells. Cold sensitive mutant tub2-401 of Saccharomyces cerevisiae is used. The measured electromagnetic signals in the frequency range from 8 to 9 MHz are compared with evolution of the reassembled microtubules. The detected signals peak in the time interval 25-30 min and 45-60 min after the release of the cells from the restrictive to the permissive temperature. The first maximum corresponds to the stage when the mitotic spindle is formed and binds chromatids. The second maximum is measured when the processes of anaphase A and of anaphase B take place.

Biosensing Techniques↗
PubMed1985

Effects of an extremely low frequency electromagnetic field on the cell division rate and plasma membrane of Paramecium tetraurelia.

The eukaryotic protozoan, Paramecium, was examined as a model for effects of pulsated electromagnetic fields (PEMF) on cells. A 72-Hz PEMF similar to fields employed clinically increased cell division rates in Paramecium by 8.5%. Two calcium transport mutants of these organisms showed differential responses to the same field. Verapamil, a calcium channel blocker, abolished any effect of PEMFs on cell division rates. A fluorescent probe that is thought to sense changes in membrane potential also manifested an altered response in the PEMF-exposed cells whereas a fluorescent lipid bilayer fluidity probe produced evidence of decreased membrane fluidity in the exposed cells. An effect of PEMFs on ion transport mediated by either a direct or indirect effect on the cell membrane is suggested by these studies.

Animals↗
PubMed2006

Extremely low-frequency electromagnetic field (ELF-EMF) does not affect the expression of alpha3, alpha5 and alpha7 nicotinic receptor subunit genes in SH-SY5Y neuroblastoma cell line.

Neuronal nicotinic acetylcholine receptors (nAChRs) are involved in a number of functional processes, including cognition, learning and memory, and alterations in their expression and/or activity have been implicated in various neurological disorders such as Alzheimer's disease (AD), Parkinson's disease and schizophrenia. Epidemiological studies have shown that exposure to electromagnetic fields (EMF) may contribute to the pathogenesis of neurodegenerative diseases such as Alzheimer's disease. Given the role of nAChRs in physiological and pathological conditions, we wondered whether an extremely low-frequency electromagnetic field (ELF-EMF) may affect the expression of the molecules involved in neurodegenerative processes. In order to investigate this possibility, we studied the expression of alpha3, alpha5 and alpha7 nicotinic subunits upon exposure of the SH-SY5Y human neuroblastoma cell line to a 50 Hz power-line magnetic field in a "blind trial" system; various magnetic flux densities and exposure times were applied. Our studies show that the expression of some relevant components of the cholinergic nicotinic system, which is one of the most affected neurotransmission systems in AD, did not undergo any change at molecular level by environmental exposure to ELF-EMF.

Blotting, Northern↗
PubMed2006

50-Hertz electromagnetic fields induce gammaH2AX foci formation in mouse preimplantation embryos in vitro.

Effects of electromagnetic fields (EMFs) on DNA damage in mammals are still controversial. In the present study, the effects of EMFs on DNA damage in preimplantation mouse embryos in vitro were investigated by using gammaH2AX foci formation, a new sensitive indicator for detecting DNA double-strand breaks (DSBs). The data obtained demonstrated that EMFs decreased the cleavage rate of preimplantation mouse embryos. This decreasing effect of EMFs was related to the DNA-damaging effect indicated by the induction of gammaH2AX foci formation in preimplantation mouse embryos. The inducing effects of EMFs on gammaH2AX foci formation could be inhibited by the treatment of noise MFs or wortmannin, a phosphatidylinositol 3-kinase (PI3K) family inhibitor. Furthermore, the data obtained also showed that EMFs could activate the DNA damage-repair mechanism by recruiting repair factor Rad50 to the damaged DNA sites to repair the corresponding DNA damage. These findings suggest that EMFs could cause DNA damage in preimplantation embryos in vitro and that the adverse effects of EMFs on development might at least partly act through DNA damage. The DNA damage induced by EMFs could be at least partly repaired by the natural activation of DNA damage-repair mechanism or prevented by the simultaneous treatment of noise magnetic fields.

ATP-Binding Cassette Transporters↗
PubMed1988

Treatment of delayed- and non-union of fractures using pulsed electromagnetic fields.

A prospective series of 32 consecutive patients, with 33 long-bone fractures suffering from delayed- or non-union were treated by pulsed electromagnetic fields (PEMF) or by PEMF with surgery. The management regime for the PEMF treatment was simpler and less rigid than that reported by Bassett et al. and our stimulation waveform was also different. Nineteen fractures (100%) treated with surgery and PEMF united within nine months of the commencement of PEMF treatment. Fourteen fractures were treated with PEMF alone. Twelve (86%) united within ten months and two failed to unite. The results of this study suggest that the stimulating waveform is less critical than is claimed by Bassett et al. and that a simpler and easier management regime for PEMF treatment can be just as effective. Alternatively PEMF may have no effect on fracture healing.

Adult↗
PubMed2006

First cell cycles of sea urchin Paracentrotus lividus are dramatically impaired by exposure to extremely low-frequency electromagnetic field.

Exposure of fertilized eggs of the sea urchin Paracentrotus lividus to an electromagnetic field of 75-Hz frequency and low amplitudes (from 0.75 to 2.20 mT of magnetic component) leads to a dramatic loss of synchronization of the first cell cycle, with formation of anomalous embryos linked to irregular separation of chromatids during the mitotic events. Because acetylcholinesterase (ACHE) is thought to regulate the embryonic first developmental events of the sea urchin, its enzymatic activity was assayed in embryo homogenates and decreased by 48% when the homogenates were exposed to the same pulsed field. This enzymatic inactivation had a threshold of about 0.75 +/- 0.01 mT. The same field threshold was found for the effect on the formation of anomalous embryos of P. lividus. Moreover, ACHE inhibitors seem to induce the same teratological effects as those caused by the field, while blockers of acetylcholine (ACh) receptors are able to antagonize those effects. We conclude that one of the main causes of these dramatic effects on the early development of the sea urchin by field exposure could be the accumulation of ACh due to ACHE inactivation. The crucial role of the membrane in determining the conditions for enzyme inactivation is discussed.

Acetylcholinesterase↗
PubMed2006

[Regulation requirements for human protection against electromagnetic fields occurring in the environment].

Issues concerning the standardization of the effects of electromagnetic fields (EMF), especially in the natural environment (widely available), are discussed in this paper. They are referred to the situation associated with the technological infrastructure in the country. Changes in Polish regulations on the human protection are presented. Basic information about these regulations, international recommendations and documents on EMF effects are also given.

Electromagnetic Fields↗
PubMed1988

The effect of long-term pulsing electromagnetic field stimulation on experimental osteoporosis of rats.

The author performed experiments in order to investigate what biological effect on the bone would be produced by long-term pulsing electromagnetic field (PEMF) systemic stimulation. In some of the mature female rats used as experimental animals, bilateral ovariectomy and right sciatic neurectomy were performed in order to make a model osteoporosis. PEMF stimulation was produced by repetitive pulse burst (RPB) waves at a positive amplitude of 25 mV, negative amplitude of 62.5 mV, burst width of 4.2 ms, pulse width of 230 microseconds and 12 Hz, with the magnetic field strength within a cage being set at 3-10 Gauss. PEMF stimulation over 6 months did not produce any effects on the physiologically aged bones. PEMF stimulation also did not produce any effects on losed cortical bone in osteoporotic hindlegs. On the other hand, an increase of bone volume and bone formation activity was observed in the cancellous bone of osteoporotic hindlegs. These findings suggested that PEMF stimulation exerted a preventive effect against bone loss of osteoporotic hindlegs. Furthermore, an observed increase in bone marrow blood flow seemed to be related with this increase of bone volume and bone formation activity.

Alkaline Phosphatase↗
PubMed1998

Human sleep under the influence of pulsed radiofrequency electromagnetic fields: a polysomnographic study using standardized conditions.

To investigate the influence of radiofrequency electromagnetic fields (EMFs) of cellular phone GSM signals on human sleep electroencephalographic (EEG) pattern, all-night polysomnographies of 24 healthy male subjects were recorded, both with and without exposure to a circular polarized EMF (900 MHz, pulsed with a frequency of 217 Hz, pulse width 577 micros, power flux density 0.2 W/m2. Suppression of rapid eye movement (REM) sleep as well as a sleep-inducing effect under field exposure did not reach statistical significance, so that previous results indicating alterations of these sleep parameters could not be replicated. Spectral power analysis also did not reveal any alterations of the EEG rhythms during EMF exposure. The failure to confirm our previous results might be due to dose-dependent effects of the EMF on the human sleep profile.

Adolescent↗