Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “electromagnetic fields”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,729 records · Page 96Linked to original sources
PubMed2006

[Protection against electromagnetic fields reports effects exerted on the environment].

This paper presents basic information about reports on the effects exterted on the environment. These reports are elaborated to meet the needs of administrative procedures concerning the evaluation of effects exerted on the environment and provide the basis on which decisions are made whether environmental determinants allow for issuing permission for taking up a given enterprise. The author discusses only a small part of a wider problem of the report formulation. Such issues as waste management, protection against noise, conservation of historical monuments and Natura 2000 areas are not raised.

Electromagnetic Fields↗
PubMed2003

In vitro studies of the influence of ELF electromagnetic fields on the activity of soluble and insoluble peroxidase.

The influence of an extremely low frequency (ELF) magnetic field (50 Hz and 1 mT, EMF) on the activity of a soluble and insoluble horseradish peroxidase (E.C. 1.11.17) has been studied as a function of time. Insoluble derivatives were obtained by enzyme entrapment into two different gelatin membranes or by covalent attachment of the enzyme on two nylon membranes, differently preactivated. Results have shown that the field affects the inactivation rate of the soluble enzyme, while no effects are observed with insoluble derivatives. Since in vivo enzymes are immobilised into the biomembrane bilayer or entrapped into the cytoplasmic mixture, one might speculate that our experimental conditions do not reflect the catalytic activity of the enzymes in vivo.

Benzothiazoles↗
PubMed1991

Analysis of exposure to electromagnetic fields during professional use of radiotelephones.

An environmental survey on exposure to EM fields covered over 300 radiotelephone operating in the range of 300-344 MHz with input power of 5 W, used by 574 radiooperators and 48 radiomechanics employed in sanitary transport, power engineering, municipal traffic and coal mining. The intensity of EM fields was measured and timing of effective radiotelephone transmitter work was done. According to the Polish standards, it was found that 3% of the population examined were subject to excessive exposure, 6%--to conditionally admissible only and 17%--to admissible. Exposure assessment, made for extreme conditions based on literature, theoretical and experimental data, showed that in radiomechanics' necks, eyes and wrists there may occur SAR values: 10-15 W/kg, 1-1.5 W/kg and 1.8 W/kg, respectively.

Electromagnetic Fields↗
PubMed1995

Biologic effects of prolonged exposure to ELF electromagnetic fields in rats: II. 50 Hz magnetic fields.

To provide possible laboratory support to health risk evaluation associated with long-term, low-intensity magnetic field exposure, 256 male albino rats and an equal number of control animals (initial age 12 weeks) were exposed 22 h/day to a 50 Hz magnetic flux density of 5 microT for 32 weeks (a total of about 5000 h). Hematology was studied from blood samples before exposure to the field and at 12 week intervals. Morphology and histology of liver, heart, mesenteric lymph nodes, and testes as well as brain neurotransmitters were assessed at the end of the exposure period. In two identical sets of experiments, no significant differences in the investigated variables were found between exposed and sham-exposed animals. It is concluded that continuous exposure to a 50 Hz magnetic field of 5 microT from week 12 to week 44, which makes up approximately 70% of the life span of the rat before sacrifice, does not cause changes in growth rate, in the morphology and histology of liver, heart, mesenteric lymph nodes, testes, and bone marrow, in hematology and hematochemistry, or in the neurotransmitters dopamine and serotonin.

Animals↗
PubMed1994

Electrochemical therapy of pelvic pain: effects of pulsed electromagnetic fields (PEMF) on tissue trauma.

Unusually effective and long-lasting relief of pelvic pain of gynaecological origin has been obtained consistently by short exposures of affected areas to the application of a magnetic induction device producing short, sharp, magnetic-field pulses of a minimal amplitude to initiate the electrochemical phenomenon of electroporation within a 25 cm2 focal area. Treatments are short, fasting-acting, economical and in many instances have obviated surgery. This report describes typical cases such as dysmenorrhoea, endometriosis, ruptured ovarian cyst, acute lower urinary tract infection, post-operative haematoma, and persistent dyspareunia in which pulsed magnetic field treatment has not, in most cases, been supplemented by analgesic medication. Of 17 female patients presenting with a total of 20 episodes of pelvic pain, of which 11 episodes were acute, seven chronic and two acute as well as chronic, 16 patients representing 18 episodes (90%) experienced marked, even dramatic relief, while two patients representing two episodes reported less than complete pain relief.

Acute Disease↗
PubMed1993

Neurobehavioral effects of power-frequency electromagnetic fields.

Some laboratory experiments have suggested that power-frequency electric and magnetic fields (EMF) may be capable of influencing calcium efflux from cell membranes, pineal function, and circadian rhythms. As yet, however, no consistent, replicable laboratory model has been developed for any of these effects. Most assessments of human volunteers exposed to EMF have been negative, but occasional effects on vigilance or alertness and some modest effects on circadian rhythmicity have been reported. Several carefully performed studies of workers occupationally exposed to high electric-field strengths have failed to find effects on behavior or cognitive functioning. Although the bulk of human research on the effects of EMF on cognitive performance is negative, there has been less assessment of behavior and psychiatric symptomatology. Because some studies, in both humans and animals, have described effects of EMF on circadian rhythms, future research might concentrate profitably on the assessment of EMF in relation to depression and other cyclically mediated psychiatric disorders.

Animals↗
PubMed1999

Observations on the effects of low frequency electromagnetic fields on cellular transcription in Drosophila larvae reared in field-free conditions.

Drosophila larvae reared inside a micro-metal box with an internal field strength 0.004 microT, were treated with a magnetic field of 50 Hz, 8 microT. for 20 min. Control experienced 0.004 microT. Cellular transcript levels were assessed using slot blots and quantified using a Phosphorimager. Blots were hybridised using probes against HSP 70a, Histone 1.9, and Copia. The low frequency EMFs very significantly decreased transcript levels, indicating that experimental responses may be influenced by previous exposure or lack of previous exposure.

Analysis of Variance↗
PubMed2006

Effects of GSM-modulated radiofrequency electromagnetic fields on B-cell peripheral differentiation and antibody production.

We examined the effects of in vivo exposure to a GSM-modulated 900 MHz RF field on B-cell peripheral differentiation and antibody production in mice. Our results show that exposure to a whole-body average specific absorption rate (SAR) of 2 W/kg, 2 h/day for 4 consecutive weeks does not affect the frequencies of differentiating transitional 1 (T1) and T2 B cells or those of mature follicular B and marginal zone B cells in the spleen. IgM and IgG serum levels are also not significantly different among exposed, sham-exposed and control mice. B cells from these mice, challenged in vitro with LPS, produce comparable amounts of IgM and IgG. Moreover, exposure of immunized mice to RF fields does not change the antigen-specific antibody serum level. Interestingly, not only the production of antigen-specific IgM but also that of IgG (which requires T-B-cell interaction) is not affected by RF-field exposure. This indicates that the exposure does not alter an ongoing in vivo antigen-specific immune response. In conclusion, our results do not indicate any effects of GSM-modulated RF radiation on the B-cell peripheral compartment and antibody production and thus provide no support for health-threatening effects.

Animals↗
PubMedDate not supplied

[Recovery processes in the cerebral cortex, myocardium and thymus of rats with experimental atherosclerosis exposed to low-frequency electromagnetic fields on the head].

Studies of animals with experimental sclerosis has shown that a course of 10 procedures of alternative magnetic field (AMF) (50 Hz, 30 mT, 3 min daily) promotes partial recovery of the lipid spectrum and corrects vasomotor-metabolic disturbances in the cerebral cortex, myocardium and thymus caused by atherosclerosis. Combination of AMF with constant magnetic field in the same regime and location does not produce a hypolipidemic effect in atherosclerotic animals and this, in combination with increased vascular permeability may aggravate the condition. Activated microcirculation, antioxidant and antiproteinase effects in activation of biosynthetic processes in the cerebral cortex reflect inhibition in the CNS in this combined effect and create conditions for a hypotensive effect.

Animals↗
PubMedDate not supplied

[Effects of electromagnetic field of thermal intensity on the hypophysis-thyroid unit of the neuroendocrine system].

Acute 12-minute exposure of laboratory rats to microwaves with specific dose rate (SAR) of 30 W/kg that exceeded a basal metabolism caused a transient response of hyppophysis-thyroid system of compensatory-adaptive character. Prolonged exposure to microwaves of less intensity (SAR = 6 W/kg, which approximately corresponds to basic metabolic rate for these animals) caused insufficiency of the function of thyroid control in a form of primary hypothyroidis.

Animals↗
PubMed1999

Electromagnetic field in and around the campus of Jawaharlal Nehru University, New Delhi.

We have surveyed the levels of magnetic field in the open environment around the high-tension lines as well as in the domestic and laboratory environment in the JNU campus. Measurements were made in the direction of most likely access, and from the surface of the appliances. The data so obtained are analyzed and compared with some quoted in the literature. It is hoped that the results will be useful for epidemiological studies in determining the criteria for safe human exposure.

Electromagnetic Fields↗
PubMed1995

Alleged health effects of electromagnetic fields: the misconceptions continue.

Exposures to electric or magnetic fields (including microwaves), in residential or occupational settings, have been reported to be associated with health problems, particularly cancer and reproductive mishaps. Misconceptions about these alleged effects continue to be published in the medical and scientific literature, as well as in popular press reports. This paper is the third in a series of papers challenging invalid statements relating to these alleged effects. Reports dealing with epidemiologic studies (including exposure assessment, consistency, and public policy implications), the use of biomarkers, and risk assessment are analyzed.

Biomarkers↗
PubMed2003

Low-frequency electromagnetic fields induce a stress effect upon higher plants, as evident by the universal stress signal, alanine.

15N NMR analysis reveals alanine production in Duckweed plants exposed to low intensity sinusoidally varying magnetic fields (SVMF) at 60 and 100Hz, and fed by 15N-labeled ammonium chloride. Alanine does not accumulate in the absence of SVMF. Addition of vitamin C, a radical scavenger, reduced alanine production by 82%, indicating the roll of free radicals in the process. Alanine accumulation in plants and animals in response to exposure to a variety of stress conditions, including SVMF, is a general phenomenon. It is proposed that alanine is a universal first stress signal expressed by cells.

Alanine↗
PubMedDate not supplied

[The hemathological reactions in rats after partial screening from natural electromagnetic fields].

The influence of partial screening of EMF on the composition of white blood cells was studied in the experiments on rats. Two kinds of copper rings were used in these experiments: individual for each rat and common for the cage. It was shown that inside the ring the composition of blood cells was changed--in 3-5 hours the number of granulocytes increased and in 24 hours it restored to the initial level. The effect was more expressive in the experiments using individual rings. In control groups the experiment with plastic rings didn't reveal this effect. It was presumed that EMF prevented the decay of granulocytes. It leads to the increase of their guantity. It was revealed that there was a positive correlation between Ki-indexes of geomagnetic field (GMF) in 1-2 days before the experiments and the number of granulocytes in rats during 1995-2002. Ki-indexes reflect the degree of GMF disturbance. During magnetic storms the spreading of EMF in radio-frequency range changes. It was presumed that the effect of partial screening of EMF of rats and the activity of magnetic storms are similar in their influence on the composition of white blood cells of rats.

Animals↗
PubMed2002

Thermal heating of human tissue induced by electromagnetic fields of magnetic resonance imaging.

The paper presents a simulation of the transient temperature distribution in the human body caused by induced eddy currents during magnetic resonance imaging (MRI). In a first simulation the validity of the used heat conduction equation was proven using a simple example of a cool-down-process of a sphere. Thereafter the heating of a phantom model with an implanted electrode placed in a MRI-System (active body coil) was examined. The resulting increase in temperature was compared with existing measurements. Finally the implications of the heating of the tissue are discussed based on the observed experimental and numerical results.

Body Temperature Regulation↗
PubMed2000

[Biological effects of nonionizing radiation: low frequency electromagnetic fields].

This article reviews various studies on effects of electric and magnetic fields of extremely low frequencies on human health and gives an overview of residential and occupational exposure to different sources, currently established exposure limitations, and protection measures. Throughout the evolution biological systems adapted to natural electric and magnetic fields. Only hundred years ago human exposure to radiation was limited to electric and magnetic fields arising either from extraterrestrial or terrestrial sources, yet both natural. For the past fifty years there has been large growth of artificial sources of electric and magnetic fields, especially with frequencies of 50 and 60 Hz (power generating and distribution systems). The concern about long-term exposure to artificial fields and possible adverse effects on human health has been entirely justified and led to numerous intensive epidemiological and laboratory studies. Results of several epidemiological studies confirm the connection between exposure to electric and magnetic fields of extremely low frequencies (up to 300 Hz) and increased risk of leukemia and brain tumor in children and adults. In addition, the risk of breast cancer in occupationally exposed population has increased. Laboratory studies on animal models, in vitro systems, and human volunteers did not confirm this connection. There is a growing interest in investigation of other possible adverse health effects such as neurodegenerative diseases (Alzheimer's disease and other forms of dementia, amyotrophic lateral sclerosis), cardiovascular disorders (arrhythmias and acute myocardial infarction), psychiatric disorders, and electrosensitivity.

Animals↗
PubMedDate not supplied

[Corrective action of the microwave electromagnetic field on progeny development in rats with impared uteroplacental circulation].

The experiment on 71 non-inbred white pregnant rats, 316 fetuses and placentas, 323 first progeny in experimental chronic impairment of uteroplacental circulation in females with pregnancy in the ploid period has found that decimetric waves (DW) in a weak heat dose (40 mW/cm2) prevents hypotrophy and disorders of fetal and placental development. Also, DW accelerate formation of motorsensory reflexes in the progeny in an early neonatal period and normalize their behavioral reactions at a mature age. The findings may serve experimental-theoretical grounds for application of weak heat DW radiation in obstetric practice in various general and regional hemocirculation.

Animals↗