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PubMedDate not supplied

[Modulation by ultralow intensity electromagnetic fields on pharmacologic effects of psychotropic drugs].

The ultralow-intensity electromagnetic fields (EMF, frequency of 4200, modulated by a quasistochastic signal in the range of 20-20,000 Hz, power density of 15 microW/cm2, specific body absorption rate up to 4.5 mJ/kg) potentiated the hypnogenic effect of hexenal. The exposure to the EMF shortened the time of falling asleep induced by this drug and increased sleep duration in rats. The exposure to the EMF also potentiated haloperidol catalepsy: it decreased the drug threshold dose and increased the catalepsy duration. The EMF influence on the haloperidol effects was of a prolonged character: it was manifest in a selected suppression of the emotional excitation in the open-field test within 24 hours after the exposure.

Animals↗
PubMed2002

[Effect of electromagnetic field produced by mobile phones on the activity of superoxide dismutase (SOD-1) and the level of malonyldialdehyde (MDA)--in vitro study].

The aim of the study was to assess in vitro the effect of electromagnetic field produced by mobile phones on the activity of superoxide dismutase (SOD-1) and the level of malonyldialdehyde (MDA) in human blood platelets. The suspension of blood platelets was exposed to the electromagnetic field with the frequency of 900 MHz for 1, 3, 5, and 7 min. Our studies demonstrated that microwaves produced by mobile phones significantly depleted SOD-1 activity after 1, 5, and 7 min of exposure and increased after 3 min in comparison with the control test. There was a significant increase in the concentration of MDA after 1, 5, and 7 min and decrease after 3 min of exposure as compared with the control test. On the grounds of our results we conclude that oxidative stress after exposure to microwaves may be the reason for many adverse changes in cells and may cause a number of systemic disturbances in the human body.

Blood Platelets↗
PubMed1999

Growth modification of human colon adenocarcinoma cells exposed to a low-frequency electromagnetic field.

The influence of variable low-intensity, low-frequency electromagnetic fields on culture cells is investigated. Human colon adenocarcinoma cells were exposed to a rectangular and variable magnetic field (1 and 25 Hz; 1.5 mT peak). Cultures were exposed to a dose for 15 and 360 minutes, and after 24 hours incubation, cell viability was measured with neutral red stain. The group treated for 15 minutes showed a statistically significant increase in cell growth with 1 Hz (p < 0.002) and 25 Hz (p < 0.003). In contrast, a significant decrease in cell growth was found in those cultures treated with 1 Hz for 360 minutes (p < 0.02). The effects reported could be influenced by the magnetic field frequency and the exposure time.

Adenocarcinoma↗
PubMed2002

Influence of 50 Hz electromagnetic fields in combination with a tumour promoting phorbol ester on protein kinase C and cell cycle in human cells.

It still is an unsolved issue whether exposure to power-line frequency electromagnetic fields (EMF) may promote carcinogenesis and if so whether it does so by influencing the proliferation, the survival, and the differentiation of cells. Since the family of protein kinases C (PKC) takes part in these processes by interacting with signal transduction pathways at several levels including the activation of transcription factors, we evaluated in the present study the effects of exposure of human amniotic fluid cells (AFC) to 50 Hz, 1 mT electromagnetic fields (EMF) alone and in combination with the tumour promoting phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) on the subcellular localization of PKC protein, on PKC enzyme activity, and on the cell cycle distribution. Quantitative analyses of the PKC expression pattern demonstrated the translocation of PKC from the cytosolic to the membrane fraction after exposure to 10, 50, 100 nM, and 1 microM TPA. EMF exposure alone showed no effect on PKC translocation. Co-exposure to 10, 50, and 100 nM TPA and I mT EMF revealed a significant additive effect (25 +/- 50, 66 +/- 29, 22 +/- 50%, respectively) with the most prominent increase at the concentration of 50 nM TPA. At the highest concentration of TPA used (1 microM) no additive effect of EMF could be observed. Data on enzymatic activity indicate that EMF modulate the PKC activity, showing a significant increase of 10 +/- 16% in total PKC activity after co-exposure to 50 nM TPA and 1 mT EMF when compared to 50 nM TPA alone. Flow cytometric analyses showed a transient cell cycle arrest in G0/G1-phase followed by a delayed transit through S-phase in response to TPA, which was, however, not enhanced by co-exposure with EMF. We conclude that in AFC cells TPA at lower concentrations (< or = 100 nM) induces a less than maximum effect on the PKC pathway, which can be enhanced by the applied EMF.

Amniotic Fluid↗
PubMed2001

Electromagnetic field monitoring and control systems: state-of-the-art and work-in-progress.

The development of EMF monitoring and control systems unquestionably represents one of the major innovations in the range of methodologies for evaluating, through measurement, the so-called environmental electromagnetic pollution. The interest recently shown by ARPA and municipal and provincial councils for setting up electromagnetic field monitoring and control systems has created significant developments in the field under examination. This paper attempts to provide a complete overview of the technical possibilities provided by electromagnetic field monitoring and control systems in the environment and their possible applications. Equipment currently available and under development is described, as well as the most significant work-in-progress in this sector. In the near future, several monitoring systems will be proposed and set up by municipalities and provinces, or directly by telecommunications companies. For this reason, it is more than ever necessary that agreement be reached at a national level to define a unified methodological and operating approach to enable monitoring data from different sources to be compared.

Electromagnetic Fields↗
PubMedDate not supplied

Stimulation of osteoblast growth by an electromagnetic field in a model of bone-like construct.

The histogenesis of bone tissue is strongly influenced by physical forces, including magnetic fields. Recent advances in tissue engineering has permitted the generation of three dimensional bone-like constructs. We have investigated the effects of electromagnetic stimulation on human osteoblast cells grown in a hydrophobic polyurethane scaffold. Bone-like constructs were stimulated by pulsed electromagnetic fields in a bioreactor. Proliferation, bone protein expression and calcified matrix production by osteoblasts were measured using histochemical methods. In stimulated cultures, the number of cells was significantly higher compared to static (control) cultures. In both stimulated and control cultures, cells were immunoreactive to osteoblast markers, including type-I collagen, osteocalcin and osteopontin, thus suggesting that the expression of bone-related markers was maintained throughout the in vitro experiments. Morphometric analysis of von Kossa-stained sections revealed that stimulation with electromagnetic field significantly increased matrix calcification. The data lend support to the view that the application of a magnetic field can be used to stimulate cell growth in bone-like constructs in vitro. This finding may be of interest for the production of biomaterials designed for clinical applications.

Animals↗
PubMed2002

Electromagnetic fields, such as those from mobile phones, alter regional cerebral blood flow and sleep and waking EEG.

Usage of mobile phones is rapidly increasing, but there is limited data on the possible effects of electromagnetic field (EMF) exposure on brain physiology. We investigated the effect of EMF vs. sham control exposure on waking regional cerebral blood flow (rCBF) and on waking and sleep electroencephalogram (EEG) in humans. In Experiment 1, positron emission tomography (PET) scans were taken after unilateral head exposure to 30-min pulse-modulated 900 MHz electromagnetic field (pm-EMF). In Experiment 2, night-time sleep was polysomnographically recorded after EMF exposure. Pulse-modulated EMF exposure increased relative rCBF in the dorsolateral prefrontal cortex ipsilateral to exposure. Also, pm-EMF exposure enhanced EEG power in the alpha frequency range prior to sleep onset and in the spindle frequency range during stage 2 sleep. Exposure to EMF without pulse modulation did not enhance power in the waking or sleep EEG. We previously observed EMF effects on the sleep EEG (A. A. Borbély, R. Huber, T. Graf, B. Fuchs, E. Gallmann and P. Achermann. Neurosci. Lett., 1999, 275: 207-210; R. Huber, T. Graf, K. A. Cote, L. Wittmann, E. Gallmann, D. Matter, J. Schuderer, N. Kuster, A. A. Borbély, and P. Achermann. Neuroreport, 2000, 11: 3321-3325), but the basis for these effects was unknown. The present results show for the first time that (1) pm-EMF alters waking rCBF and (2) pulse modulation of EMF is necessary to induce waking and sleep EEG changes. Pulse-modulated EMF exposure may provide a new, non-invasive method for modifying brain function for experimental, diagnostic and therapeutic purposes.

Adult↗
PubMed1987

Evidence that pulsed electromagnetic fields inhibit coupling of adenylate cyclase by parathyroid hormone in bone cells.

To investigate the biochemical effects of pulsed electromagnetic fields (PEMF) on bone in particular and on cell membrane-associated activity in general, we have studied the modification by PEMF of cAMP metabolism in primary calvarial bone cells. We report that PEMF inhibited cAMP accumulation stimulated by bovine PTH(1-34) peptide. After a 1-hr PEMF exposure, the cAMP response to PTH (2-7 min) was decreased in exposed cells to 48-70% (p less than 0.05) of the response of unexposed cells; furthermore, this inhibition disappeared after 10-20 min with PTH. This inhibition occurred at submaximal PTH doses (2.4-7.3 nM) and no effect was observed at maximal PTH doses (24 nM). Thus with PEMF, the dose response curve for PTH became 0.5 log unit less sensitive. PEMF did not affect the cAMP response to cholera toxin and forskolin. However, when submaximal doses of both forskolin (0.5-1.0 microM) and PTH (0.24-2.4 nM) were used, forskolin prevented inhibition of cAMP production by PEMF in the range of fields and stimulus epochs which normally inhibit cAMP production. It is proposed that PEMF inhibits PTH-stimulated coupling of the adenylate cyclase system and that this inhibition does not affect the intrinsic activity of the G-protein and the catalytic subunit.

Adenylyl Cyclases↗
PubMed1999

Effect of 50 Hz sinusoidal electromagnetic field on the kinetics of 14CO2 exhalation after [14C]-N-nitrosodiethylamine administration in mice.

N-Nitrosodiethylamine (NDEA) has been identified as a typical environmental carcinogen. Its metabolism was studied in mice under the influence of an electromagnetic field (EMF). After intraperitoneal administration of [14C]-NDEA, 0.2 microCi/100 g body weight resulted in 22.8% of the total radioactivity exhaled as 14CO2 within 1 h. Mice were exposed to a 50 Hz, 2 mT (rms) electromagnetic field, 8 h/day for 8 weeks. There was a significant increase in the metabolic turnover of [14C]-NDEA into 14CO2 at the end of both 6 and 8 weeks of field exposure, i.e., 26.9% and 37.4% respectively. The enhanced capacity of mice to metabolize NDEA after the exposure to EMF may result in animals with a smaller amount of the bioactive carcinogen burden, thereby indicating a protective role of 2 mT EMF in a whole animal study.

Animals↗
PubMed1980

[Effect of an industrial-frequency electromagnetic field on protein biosynthesic processes of embryonal fibroblasts in tissue culture].

Using radioautography, the influence of the industrial frequency electromagnetic field (50 cps) (EMF i/f), with the tension of 50 and 150 kv/m was studied, on the synthesis of collagen and non-collagen proteins in cultured fibroblast-like human embryo cells in the presence and absense in the medium of adrenaline and of cyclic adenosine monophosphate (cAMP). The EMF depresses protein proportionally to its intesity and duration. The specific function of fibroblasts -- the synthesis of collagen -- is subject to this influence to a great extent. The preliminary administration of adrenaline or cAMP prevented the above changes. The cyclic AMP exerted a much stronger protective effect.

Collagen↗
PubMed1998

[Intensity of electromagnetic field and electric current on human bodies induced by electric blanket].

OBJECTIVE: To study the effects of various factors, such as different carriers, with or without ground connection to a blanket and status of its switch, on electromagnetic field induced. METHODS: To determine electric field, magnetic field and electric current on human bodies induced by electric blanket with a temperature--adjustable semiwave rectifier diode, which was domestically popular. RESULTS: Temperature was adjusted and controlled by a diode serially connected to its switch is put on and the blanket, with or without short circuit. When the switch is put on and the blanket is running in low temperature, if the diode is serially connected to the ground end of the power source, the intensities of electromagnetic field and current on the human bodies induced by the blanket was higher than those running in high temperature. CONCLUSION: The most important factor influencing field intensities of the electric blanket is in its switch.

Bedding and Linens↗
PubMedDate not supplied

Measurements of electromagnetic fields radiated from communication equipment and of environmental electromagnetic noise: impact on the use of communication equipment within the hospital.

The increasing use of all types of cellular telephones requires the formulation of new standards to ensure the immunity of electronic medical equipment to electromagnetic radiation. It will be many years before all hospital medical equipment conforms to new and higher standards. Until that time, the medical, security, maintenance, and other staff will need to be ever vigilant regarding restrictions on the use of wireless equipment within the hospital, to prevent potential danger to the lives of the patients. A comprehensive hospital policy must be formulated to reduce risks to patients from equipment susceptible to electromagnetic interference (EMI). Such an aim should address the following needs: To devise a uniform policy for the instruction of hospital staff, visitors, and patients, thereby reducing confusion regarding the use of cellular telephones, beepers, and portable transceivers. To implement a policy that avoids unwarranted restrictions but does not ignore statistical evidence regarding potential EMI problems. To allow comparison, with other clinical facilities, of the benefits derived from such a policy.

Electric Power Supplies↗
PubMedDate not supplied

[Effect of an electromagnetic field on subtilisin from Bacillus subtilis 316 m].

The influence of electromagnetic field on the subtilisin of Bacillus subtilis strain 316 M preparation has been studied. It is the increase 30-60% of the proteolytic activity during 60-100 min treatment was observed. The effect of activation is stable for a month at +4 degrees C. The increase of the proteolytic activity is connected with conformational changes of the enzyme molecule, with the decrease of pI from 11.4 to 9.2 in particular.

Bacillus subtilis↗
PubMed1991

Alleged health effects of electromagnetic fields: misconceptions in the scientific literature.

Occupational or residential exposures to electromagnetic fields or microwaves have been alleged to result in health problems, including leukemia, other cancers, and reproductive mishaps. Several recent articles and editorials in the medical and scientific literature have presented misconceptions regarding the alleged effects. Some misleading or illogical statements were challenged in letters-to-the-editor. Additional unsubstantiated or invalid assertions contained in subsequent responses to some of the letters have been addressed in this paper. The articles in question included a case report concerning acute myelogenous leukemia, an editorial regarding the safety of magnetic resonance imaging, commentaries suggesting a link between exposure to video display terminals and reproductive mishaps, and several reviews of a book written for a lay audience.

Electromagnetic Fields↗
PubMed1991

Treatment of chronic varicose ulcers with pulsed electromagnetic fields: a controlled pilot study.

To evaluate the efficacy of pulsed electromagnetic fields (PEMF) in healing of chronic varicose ulcers, 19 patients with this condition were included in a double-blind controlled clinical trial. All patients received standard ulcer therapy throughout the duration of the study and were randomly divided into two groups to receive either active or inactive PEMF therapy. Active therapy was provided by the use of a pait of helmholtz coils on a twice weekly basis over a five week period and inactive therapy was provided on an identical regimen with identical coils wound so that no magnetic field was produced when an electric current was passed through them. The clinician and patients were unable to distinguish the active or inactive coils. No statistically relevant difference was noted between the two groups in the healing rates of the ulcer, change in the lower leg girth, pain or infection rates. However there was a trend in favour of a decrease in ulcer size and lower leg girth in the group treated with active PEMF. As PEMF is a novel treatment for chronic varicose ulcers, more work needs to be done to establish treatment parameters and its usefulness in the treatment of this condition.

Aged↗
PubMed2004

Effect of 910-MHz electromagnetic field on rat bone marrow.

Aiming to investigate the possibility of electromagnetic fields (EMF) developed by nonionizing radiation to be a noxious agent capable of inducing genotoxicity to humans, in the current study we have investigated the effect of 910-MHz EMF in rat bone marrow. Rats were exposed daily for 2 h over a period of 30 consecutive days. Studying bone marrow smears from EMF-exposed and sham-exposed animals, we observed an almost threefold increase of micronuclei (MN) in polychromatic erythrocytes (PCEs) after EMF exposure. An induction of MN was also observed in polymorphonuclear cells. The induction of MN in female rats was less than that in male rats. The results indicate that 910-MHz EMF could be considered as a noxious agent capable of producing genotoxic effects.

Animals↗
PubMed1976

Experimental regeneration in peripheral nerves and the spinal cord in laboratory animals exposed to a pulsed electromagnetic field.

Peripheral nerve section and suture was performed in 132 rats. Postoperatively half the animals were exposed to a pulsed electromagnetic field each day and half were kept as controls. Nerve conduction studies, histology and nerve fibre counts all indicated an increased rate of regeneration in the treated animals. A similar controlled study of spinal cord regeneration following hemicordotomy in cats has been started, and preliminary results indicate that when the animals are sacrificed three months after the hemicordotomy, the pulsed electromagnetic therapy has induced nerve fibre regeneration across the region of the scar.

Animals↗
PubMedDate not supplied

Biological effects of PEMF (pulsing electromagnetic field): an attempt to modify cell resistance to anticancer agents.

Pulsing Electromagnetic Field (PEMF) effects lead to a modification of the multidrug resistance (MDR) of cells in vitro and in vivo. The murine leukemic doxorubicin-resistant cell line, P388/Dx, subjected to PEMF irradiation in vitro, showed a significant difference in thymidine incorporation when the concentration of doxorubicin reached a level of 1 microgram/mL, which corresponds to the inhibition dose 50 (ID50). The human lymphoblastic leukemia vinblastine-resistant cell line, CEM/VLB100, also showed a significant modification under the same experimental conditions at the in vitro ID50 corresponding to a vinblastine concentration of 100 ng/mL. BDF1 mice transplanted with P388/Dx cells also had an increase in their life span when doxorubicin was injected intraperitoneally in fractionated doses, while being subjected to PEMF irradiation.

Animals↗