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PubMed1980

[Histochemical study of the cholinesterase activity in the structures of the rat heart normally and during exposure to a pulsed electromagnetic field].

Histotopography and activity of true and false cholinesterases in the non-inbred white rat hearts, normal and at the effect of pulsed electromagnetic field (80 kA/m) have been demonstrated by Karnovsky-Roots histochemical method. It has been stated that a single 6 hours' application of the pulsed electromagnetic field results in an increased cholinesterase activity in all cardiac structures, besides neurocytes. If the application is continued, cholinesterase activity is progressively decreasing and its minimum is observed on the 10th day of the stimulation. From the 15th day on, increasing enzymatic activities are observed, various for different enzymes: that of acetylcholinesterase even by the 30th day of the stimulation by the magnetic field does not reach the normal level, while that of cholinesterase exceeds this level. Mast cells are noted to appear along the cholinergic neural fibres. A suggestion is made on possible exchange between them by mediator acetylcholine. Electrocardiographic data have demonstrated that certain correlation exists between acetylcholinesterase activity and the cardiac function.

Acetylcholinesterase↗
PubMed2003

[Measurements of electromagnetic fields and evaluation of occupational exposure: PN-T-06580:2002 requirements and principles adopted in the European Union].

Under the process of developing a uniform system of protection against excessive exposure to electromagnetic fields, Polish metrological standards have been amended as an inherent complement of the modified decree on maximum admissible strength (MAS) values, issued by the Minister of Labour and Social Policy. Two parts of standard PN-T-06580:2002 were established by the Chairman of the Polish Committee for Standardisation in 2002. Of the whole range of frequencies covered by legal regulations, it laid down the principles of evaluation of occupational exposure to electromagnetic fields and radiation, providing precise definitions and rules for estimation actual dose and exposure factor in each case of exposure in real conditions. The standards also precise conditions, in which simplified principles of occupational exposure measurement and evaluation can be applied. Currently in the European countries, there are no general standards concerning methods of measuring and evaluating occupational exposure to 0-300 GHz electromagnetic fields. The provisions of numerous European (EN) and international (IEC) standards of a much narrower scope of application are similar to those formulated in standard PN-T-06580:2002.

Dose-Response Relationship, Radiation↗
PubMed1994

Effects of short term exposure to 60 Hz electromagnetic fields on interleukin 1 and interleukin 6 production by peritoneal exudate cells.

The relationship between exposure to electromagnetic fields (EMF) and human health is of increasing interest. Exposure to EMF has been linked to leukemia and brain tumors in some but not all epidemiological studies. The effects of separate and combined alternating electric and magnetic fields on interleukin 1 (IL-1) and interleukin 6 (IL-6) production were measured in this study. Helmholtz coils and parallel plate electrodes were used to create uniform field characteristics (300 V/in., 0.3 mT). Effects were studied at a combined field frequency of 60 Hz. This frequency did not elevate culture temperatures above ambient room temperature. Murine thioglycollate-elicited peritoneal exudate cells (PEC) were exposed to an electric field (E), magnetic field (M), combined electric and magnetic field (EM), or no field (control). Three samples of PEC from each mouse were cultured with lipopolysaccharide in each field. Using commercial ELISA kits, supernatants of cell cultures were tested in duplicate after 24 hours of exposure for IL-1 alpha levels and after 48 hours of exposure for IL-6 levels. Results were evaluated using one-way analysis of variance (ANOVA). As a group, IL-1 production by the PEC from five mice and IL-6 production by the PEC from nine mice were unaffected by electric, magnetic, or combined electric and magnetic fields. Results from these experiments indicate that the 24-hour exposure to 60 Hz electric, magnetic, or combined electromagnetic fields had no effect on IL-1 production. Forty-eight hours of exposure to the same fields did not affect IL-6 production.

Analysis of Variance↗
PubMed1976

Electromagnetic field interference and cardiac pacemakers.

The physical and physiological effects of electromagnetic field interference on 440 patients with cardiac pacemakers were determined by reviewing the literature from 1949 to 1973. The sources, mechanisms, and findings of physiological dysfunction and ventricular fibrillation in patients with pacemakers are presented. Shortwave and microwave diathermy and electrical stimulators have been found to have a definite adverse influence on some cardiac pacemakers. The effect of interference may be an increase or decrease in pacemaker rate or rhythm, ventricular fibrillation, a total loss of pacing, or cessation of impulses. Because all pacemaker units are not resistant to interference, no ungrounded electrical equipment and no equipment such as microwave diathermy, short wave diathermy, and electrical stimulators should be placed on, or near, a patient with a cardiac pacemaker.

Diathermy↗
PubMed1988

Pulsed electromagnetic field treatment failure in radius non-united fracture healing.

Pulsed electromagnetic field (PEMF) treatment is a non-invasive technique which has wide use in promoting healing of delayed union and non-union of bone. According to reports in the literature, PEMF has a 'success' of about 70%, but with no clear-cut reason to explain the failures. Our tests were carried out on 11 patients with radius non-unions and delayed unions; the results suggest that PEMF failure is associated with implanted metallic plates. In our view, this can be explained because the conducting plates create a uniform bone biopotential around the fracture and thus prevent the negative polarization which stimulates callus formation. Although further controlled and randomized clinical tests are needed, our results indicate that it may be necessary to remove the plates before PEMF application.

Adolescent↗
PubMed1994

Pulsating electromagnetic field stimulates mRNA expression of bone morphogenetic protein-2 and -4.

The effects of a pulsating electromagnetic field on mRNA expression of bone morphogenetic protein-2 and -4 in chick embryonic calvaria were examined. From the onset of embryogenesis (Day 0), chick embryos were incubated in a continuously generated pulsating electromagnetic field with a peak of 3.5 milli-Tesla (mean: 2 milli-Tesla) and vibration at 15 Hz. Control chicks were incubated in a normal magnetic field. Northern-blot analysis showed that the mRNAs of bone morphogenetic protein-2 and -4 were expressed in the calvaria. Quantitative analysis of the mRNA expressions was done by means of slot-blot hybridization. The magnetic field enhanced the expressions of both mRNAs. The enhancements were more pronounced in younger chick embryos (Day 15 > Day 17), and no significant change was observed in the 19-day-old embryos. These results indicate that osteo-inductive effects of the magnetic field were mediated at least in part by bone morphogenetic protein-2 and -4.

Animals↗
PubMed1989

DNA repair after gamma irradiation in lymphocytes exposed to low-frequency pulsed electromagnetic fields.

The effect of exposure to extremely low-frequency pulsed electromagnetic fields (EMFs) on DNA repair capability and on cell survival in human lymphocytes damaged in vitro with gamma rays was studied by two different micromethods. In the first assay, which measures DNA repair synthesis (unscheduled DNA synthesis, UDS), lymphocyte cultures were stimulated with phytohemagglutinin (PHA) for 66 h and then treated with hydroxyurea (which blocks DNA replication), irradiated with 100 Gy of 60Co, pulsed with [3H]thymidine ([3H]TdR), and then exposed to pulsed EMFs for 6 h (the period in which cells repaired DNA damage). In the second assay, which measures cell survival after radiation or chemical damage, lymphocytes were first irradiated with graded doses of gamma rays or treated with diverse antiproliferative agents, and then stimulated with PHA, cultured for 72 h, and pulsed with [3H]TdR for the last 6 h of culture. In this case, immediately after the damage induced by either the radiation or chemicals, cultures were exposed to pulsed EMFs for 72 h, during which cell proliferation took place. Exposure to pulsed EMFs did not affect either UDS or cell survival, suggesting that this type of nonionizing radiation--to which humans may be exposed in the environment, and which is used for both diagnostic and therapeutic purposes--does not affect DNA repair mechanisms.

Adolescent↗
PubMed1994

Enhancement of functional recovery following a crush lesion to the rat sciatic nerve by exposure to pulsed electromagnetic fields.

Previous studies showed that exposure to pulsed electromagnetic fields (PEMF) produced a 22% increase in the axonal regeneration rate during the first 6 days after crush injury in the rat sciatic nerve. We used the same injury model to assess the effect on functional recovery. The animals were treated with whole body exposure to PEMF (0.3 mT, repetition rate 2 Hz) for 4 h/day during Days 1-5 while held in plastic restrainers. Functional recovery was serially assessed up to Postinjury Day 43 using recently described video imaging of the 1-5 toe spread and the gait-stance duration. Footprint analysis was also used with calculation of a sciatic function index. Those animals treated with PEMF had improved functional recovery, as compared to sham controls, using the tests for video 1-5 toe spread and gait-stance duration (P = 0.001 and P = 0.081, respectively). This effect was found throughout the 43-day recovery period. No effect was found using the sciatic function index. This study confirms that functional recovery after nerve crush lesion is accelerated by PEMF and has broad implications for the clinical use of these fields in the management of nerve injuries.

Animals↗
PubMed1990

Effects of pulsing electromagnetic fields on the prenatal and postnatal development in mice and rats: in vivo and in vitro studies.

Electromagnetic fields (EMF) might have various biological effects on the developing embryo. We studied the effects of pulsing electromagnetic fields (PEMF) on the in vitro development of preimplantation mouse embryos and of early somite rat embryos as well as on the in vivo development of rat embryos. We used PEMF at frequencies of 1, 20, 50, 70, and 100 Hz with a tension of 0.6 V/m. The embryos were exposed to PEMF throughout the experimental period. PEMF at frequencies of 20 and 50 Hz were embryotoxic, inhibiting over 50% of blastocysts from hatching and further development, all within 72 h of culture. PEMF at frequencies of 50 and 70 Hz induced 22% and 30% incidence of malformations in 10.5 day old rat embryos after 48 h in culture. The main malformations were absence of telencephalic, optic, and otic vesicles and of forelimb buds. In addition, retarded growth and development manifested by fewer somites, reduction in crown-rump length, and retarded closure of the neural tube were found in many embryos. No significant pathological changes were found by TEM in PEMF-exposed embryos. Disappearance of microvilli and collapse of apical parts of endodermal cells were observed by SEM in many yolk sacs of embryos exposed to 50 and 70 Hz PEMF. A slightly reduced litter average, a reduction or increase of weight, and a delay in eye opening was observed among offspring of pregnant rats exposed throughout pregnancy to PEMF at frequencies of 20, 50, and 100 Hz. No malformations were observed among these offspring. The mechanism of PEMF-induced embryotoxicity and teratogeneity is unknown, as is the mechanism of the "protective effects" of the mother on the rat embryos exposed to PEMF in vivo.

Abnormalities, Multiple↗
PubMed1987

Leukemia and occupational exposure to electromagnetic fields: review of epidemiologic surveys.

Several recent surveys have presented data suggesting an increased risk of leukemia among men with occupational exposure to electromagnetic fields. Eleven pertinent data sets were compiled in order to assess the consistency of this pattern and to identify those occupations most deserving closer examination. Results for total leukemia show a modest excess risk for men in exposed occupations, with an enhanced risk elevation for acute leukemia and especially acute myelogenous leukemia. These studies are inherently limited regarding the effect of electromagnetic fields due to the absence of exposure characterization. Nonetheless, telegraph, radio, and radar operators, power and telephone linemen, and electrical and electronic engineers showed the most consistent results and warrant further study to ascertain potential occupational health hazards.

Acute Disease↗
PubMed2006

The effects of microwave frequency electromagnetic fields on the development of Drosophila melanogaster.

PURPOSE: To investigate the effects of microwave frequency electromagnetic fields (EMF) on the development of Drosophila melanogaster. MATERIALS AND METHODS: Larvae of D. melanogaster were exposed to 10 GHz EMF continuously (3 h, 4 h and 5 h) and discontinuously (3 h exposure + 30 min interval + 3 h exposure). The percentages and times of transition from larvae to pupae and from pupae to adults were determined, and the mean offspring number was examined using the offspring of the females which had been exposed as larvae. RESULTS: No differences were found in the transition percentages from larvae to pupae and from pupae to adults (p > 0.05). However, it was found that the mean pupation time was delayed linearly with an increasing electromagnetic field (EMF) exposure period (p < 0.05). In the 3 + 3-h exposed group (E3 + 3), the mean offspring number was significantly less than that of the control (p < 0.05). CONCLUSIONS: 10 GHz EMF can cause developmental delay and decrease the number of offspring in D. melanogaster.

Animals↗
PubMed1992

[An automated system for the collective protection from harmful exposure to the Veneta superhigh-frequency electromagnetic field of military units and the civilian population].

In the up-to-date exploitation of electromagnetic field generators more and more clearly stands out the problem for radiation protection of people from the biological effect of microwave radiation. In order to solve this problem an automatized system is developed, with the purpose to define according to numerical methods the areas of standardized radiation, where the stay depends on the exposure. On the basis of the developed product are statistical data of the values of the ionized radiation parameters and the algorithm for radiation and hygienic guarantee the exploitation of products emitting superhigh frequency magnetic fields, the average power and strength of the energy flow of which are determined by the impulse power of radiation and measurement in the so called "free area". The system is a first stage for group protection from superhigh frequency electromagnetic field, which afterwards to be approbated by means of apparatus dosimetric examinations.

Algorithms↗
PubMed1991

Electromagnetic fields: biological and clinical aspects.

Our entire biosphere is immersed in a sea of man-made electromagnetic fields (EMF). Occupational and public health data suggest that these fields may be a health hazard, possibly involving cancer and fetal loss. This paper reviews the history and pertinent physics of electromagnetic fields and presents evidence from the authors' work, and that of others, of biological interaction with living systems. Epidemiological data suggesting EMF hazards are reviewed including a discussion of possible risks associated with Hawaii's Lualualei transmitter site, TV and FM antennas in high-density population areas, fields surrounding electric power transmission and computer terminals, and the plan to route a major highway through the near-field of an operating Omega signal-source. In the face of current public fear and controversial research reports about long-term EMF exposure, suggestions are presented for public policy about these local sources of concern, as well as for the EMF risks common to any similarly developed areas.

Electromagnetic Fields↗
PubMed1998

Biologic effects of low-level electromagnetic fields: current issues and controversies.

There is uncertainty and controversy about the extent to which low level electromagnetic fields may cause deleterious effects, but even experts who are skeptical about many supposed hazards are willing to agree that electromagnetic fields even weaker than those in the MR environment can have effects under certain conditions. In order that readers can familiarize themselves enough with the subject to make an informed independent assessment, discuss it knowledgeably in public, and have the means with which to evaluate new developments and avoid experimental pitfalls if planning their own research in the area, they are provided with some of the most recent finding of in vitro and in vivo research from outside the MR literature as well as some of the results and controversies coming from recent epidemiological studies.

Electromagnetic Fields↗
PubMed2003

The possible role of electromagnetic fields in bacterial communication.

This paper presents a general review of the current knowledge regarding bacterial communication via electromagnetic fields. The possible role of ultraviolet, visible and infrared light, extremely high frequency and low frequency electromagnetic fields as well as sound waves is discussed. The probable mechanisms of remote microbial interactions are raised. Future trends in the area of microbiology are also viewed.

Acoustics↗
PubMed2005

Impact of the displacement current on low-frequency electromagnetic fields computed using high-resolution anatomy models.

We present a comparison of simulated low-frequency electromagnetic fields in the human body, calculated by means of the electro-quasistatic formulation. The geometrical data in these simulations were provided by an anatomically realistic, high-resolution human body model, while the dielectric properties of the various body tissues were modelled by the parametric Cole-Cole equation. The model was examined under two different excitation sources and various spatial resolutions in a frequency range from 10 Hz to 1 MHz. An analysis of the differences in the computed fields resulting from a neglect of the permittivity was carried out. On this basis, an estimation of the impact of the displacement current on the simulated low-frequency electromagnetic fields in the human body is obtained.

Electric Conductivity↗
PubMed2006

[Regulation requirements for the protection of workers against electromagnetic fields occurring in the work environment].

In Poland, electromagnetic fields (EMF), one of potentially hazardous physical factors occurring in the work environment, are subjected to compulsory surveillance. In 2001, the Directive issued by the Minister of Labor and Social Policy substantially changed the approach towards the protection of workers against EMF. The Directive regulates the whole range of EMF frequencies and electromagnetic radiation, namely from 0 Hz to 300 GHz, which means the possibility of assessing worker's EMF exposure, determined by exposure index, along with the hygiene assessment of EMF sources, defined by protection zones. In 2003-2005, a number of amended executive and supplementary regulations were issued. However, it should be emphasized that in the process of their elaboration, striving after perfection, numerous incoherent and ambiguous provisions were adopted, which finally created difficulties in the interpretation of individual regulations. This is also linked with doubts and discussions on their practical application by services responsible for control, measurements and monitoring of working conditions under the exposure to EMF. In this work an attempt was made to clarify all issues and arrange them according to the faced problems. The authors also present proposals how to solve all these problems.

Electromagnetic Fields↗