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PubMed2003

[Effects of extremely low frequency electromagnetic fields on male reproduction in mice].

OBJECTIVE: To investigate the effects of extremely low frequency electromagnetic fields (ELF EMFs) on male reproduction in mice. METHODS: 94 adult male mice were exposed to 50 Hz sinusoidal electromagnetic fields of 0.2, 3.2 or 6.4 mT for 2 weeks or 4 weeks. Testicular histology and weight, sperm amount, sperm motility and morphology were measured. The percentages of different ploidy cells and cell phases, and DNA content of testis cells were estimated by flow cytometry. The micronucleus rate of bone-marrow cell was also observed. RESULTS: The testicular weight of the mice exposed to 6.4 mT for 4 weeks [(76.06 +/- 32.25) mg] was significantly lower than that of the control [(111.44 +/- 19.99) mg, P < 0.05]; no significant histopathological changes were observed on the testis in EMFs exposed mice;the sperm amount was decreased after EMFs exposure for 4 weeks, and those of the mice exposed to 0.2 mT and 6.4 mT for 4 weeks [(4.87 +/- 0.94) x 10(6)/ml and (4.30 +/- 1.89) x 10(6)/ml respectively] were significantly lower than that of the control [(6.67 +/- 0.70) x 10(6)/ml, P < 0.05]; the rates of sperm motility also showed a decline. After 0.2, 3.2 or 6.4 mT EMFs exposure for 2 weeks, the deformity rates of sperm [(7.416 +/- 3.352)%, (6.862 +/- 2.947)% and (8.112 +/- 4.615)% respectively] were significantly higher than that of the control [(4.098 +/- 2.028)%, P < 0.01]. Similarly, those of the mice exposed for 4 weeks [(10.267 +/- 3.836)%, (11.027 +/- 7.059)%, (8.814 +/- 3.678)% respectively] were higher than that of the control [(3.714 +/- 1.830)%]. After 6.4 mT exposure for 2 weeks, the percentages of 1C testis cells [(69.56 +/- 4.07)%] was significantly lower than that of the control [(73.45 +/- 3.10)%, P < 0.05]. There were not any remarkable changes in those of 2C, 4C cells. DNA content in different ploidy cells of the mice exposed to 6.4 mT was decreased. Moreover, the cell percentage in S phase was increased significantly (P < 0.01). CONCLUSION: ELF EMFs exposure may have some adverse effects on reproduction in mice.

Animals↗
PubMed1989

Bio-effects of extremely low frequency electromagnetic fields (60 Hz.) on the healing of corneal epithelial wound: an in vitro study.

The organ cultures of standardized epithelial wound of rabbit cornea, were exposed to electric and magnetic fields components of the extremely low frequency (60 Hz) sinusoidal electromagnetic field, separately or in combination. The electric field was applied as a pure electric current via an agar-salt bridge, and the magnetic field component was applied as a pure polarized magnetic field by means of a pair of energized coils in a Helmholtz configuration. The two field components were at right angles to each other and in phase (phi = 0 degrees) when applied in combination. Their vectors or planes of polarization were parallel to the surface of the culture dish. The three exposure combinations used were: a) electric current density of 0.19 V/m (30 microA/cm2) and/or magnetic fields strength of 1.0 Gauss. (low intensity) b) electric current density of 0.31 V/m (50 microA/cm2) and/or magnetic fields strength of 1.5 Gauss. (medium intensity) c) electric current density of 0.57 V/m (90 microA/cm2) and/or magnetic fields strength of 2.5 Gauss. (high intensity). After 2 days of exposure the incorporation of radiolabelled thymidine into DNA of the regenerating epithelial cells was determined. Results showed thymidine incorporation (adjusted by regression for differences in the levels of DNA in corneal wound) (DNA*) depended upon the electromagnetic field strength. The only significant effect on this outcome, was an interaction effect between the electric (E) and magnetic (M) fields employed. The size and direction of this interaction depended strongly on the maximum field strengths. At the lowest level DNA* was significantly lower when both fields were present than would be expected from the effects of either field alone. At the highest level, DNA* was significantly higher. There were no significant effects for medium field strengths.

Animals↗
PubMed2003

[Limitations of occupational exposure to electromagnetic fields adopted by Polish law from the perspectives of international documents with particular reference to fields of low and medium frequencies].

Following the provisions of the decree on maximum admissible strength (MAS) values, issued by the Minister of Labour and Social Policy, comprehensive and homogeneous principles of workers' protection against excessive exposure to 0-300 GHz electromagnetic fields have been in force since 2001. Different mechanisms responsible for interactions between electromagnetic field and human body, as well as the need to limit their harmful effects were taken into account while setting permissible exposure conditions. Owing to the fact that both the strength of electric and magnetic fields and exposure duration have been considered, Polish regulations facilitate a parallel harmonisation of the prohibited exposure levels with so-called "basic restriction" values adopted as a minimum protection level in many international guidelines and to implement a significantly higher level of workers' protection in case of long-duration per shift exposure (equivalent of "precautionary principle" applied in the evaluation of general public exposure). The approaches adopted in Polish regulations coincide in many points with a drafted EU directive. Amendments being introduced into Polish legal regulations on the environmental protection should maintain cohesion principle with legal regulations on occupational exposure to electromagnetic fields, and should take into account additional restrictions concerning the protection of residential areas, as practiced in many European countries.

Dose-Response Relationship, Radiation↗
PubMed2004

[Health protection against electromagnetic fields].

In recent years there has been an increasing social concern in Spain about electromagnetic fields (EMF) and their effects on human health. Some groups have expressed their opposition to antennas of base stations and high voltage power transmission lines. The present article discusses the current status of health protection against EMF in Spain. The assessment is based on the background and justification of the European Union Council Recommendation of 12 July 1999 on the limitation of exposure of the general population to electromagnetic fields (0 Hz to 300 GHz), the Spanish Royal Decree 1006/2001 on health protection against radioelectric emissions and the most relevant epidemiological studies. The need for implementation of a comprehensive approach based on risk assessment and the precaution principle is emphasized. In order to be coherent with the Council Recommendation and Spanish EMF legislation some strategies for health protection are proposed.

Electromagnetic Fields↗
PubMed2006

[Electromagnetic hazards from electrosurgery--assessment of occupational exposure to electromagnetic field and currents induceed in the body].

The investigation of the occupational exposure to electromagnetic fields from electrosurgery devices were done (according to the requirements of Polish Standard PN-T-06580:2002). The exposure was evaluated following the criteria established by occupational safety and health regulations. The measurements and evaluation of the currents flowing through the exposed workers body were also conducted following the method and criteria published by IEEE standard and European Directive 2004/40/EC. It was found that in the vicinity of electrosurgical devices, the area of electromagnetic fields to which only workers operating the source of field should be exposed can exist up to the distance of 70 cm from the active electrode and supplying cables. In the case when the cables are placed directly on the surgeon body or long duration of the daily exposure the overexposure of workers can appear (referring to Polish regulations). The current flowing through the arm of surgeon keeping the electrode with electric field of the maximum strength (app. 1000 V/m or higher) can exceed permissible value of 40 mA established by the Directive 2004/40/EC for contact current. The reduction of the surgeon exposure can be reached by the proper positioning of the cables supplying monopolar electrode or by the use of bipolar electrode.

Electric Conductivity↗
PubMed2002

Electromagnetic fields for the treatment of osteoarthritis.

BACKGROUND: As the focus for osteoarthritis (OA) treatment shifts away from drug therapy, we consider the effectiveness of pulsed electric stimulation which is proven to stimulate cartilage growth on the cellular level. OBJECTIVES: 1)To assess the effectiveness of pulsed electric stimulation for the treatment of osteoarthritis (OA). 2) To assess the most effective and efficient method of applying an electromagnetic field, through pulsed electromagnetic fields (PEMF) or electric stimulation, as well as the consideration of length of treatment, dosage, and the frequency of the applications. SEARCH STRATEGY: We searched PREMEDLINE, MEDLINE, HealthSTAR, CINAHL, PEDro, and the Cochrane Controlled Trials Register (CCTR) up to and including 2001. This included searches through the coordinating offices of the trials registries of the Cochrane Field of Physical and Related Therapies and the Cochrane Musculoskeletal Group for further published and unpublished articles. The electronic search was complemented by hand searches and experts in the area. SELECTION CRITERIA: Randomized controlled trials and controlled clinical trials that compared PEMF or direct electric stimulation against placebo in patients with OA. DATA COLLECTION AND ANALYSIS: Two reviewers determined the studies to be included in the review based on inclusion and exclusion criteria (JH,VR) and extracted the data using pre-developed extraction forms for the Cochrane Musculoskeletal Group. The methodological quality of the trials was assessed by the same reviewers using a validated scale (Jadad 1996). Osteoarthritis outcome measures were extracted from the publications according to OMERACT guidelines (Bellamy 1997) and additional secondary outcomes considered. MAIN RESULTS: Only three studies with a total of 259 OA patients were included in the review. Electrical stimulation therapy had a small to moderate effect on outcomes for knee OA, all statistically significant with clinical benefit ranging from 13-23% greater with active treatment than with placebo. Only 2 outcomes for cervical OA were significantly different with PEMF treatment and no clinical benefit can be reported with changes of 12% or less. REVIEWER'S CONCLUSIONS: Current evidence suggests that electrical stimulation therapy may provide significant improvements for knee OA, but further studies are required to confirm whether the statistically significant results shown in these trials confer to important benefits.

Clinical Trials as Topic↗
PubMed2005

Coherent-mode representation of a statistically homogeneous and isotropic electromagnetic field in spherical volume.

It is known that statistically stationary, homogeneous, and isotropic source distributions generate, in an unbounded low-loss medium, an electromagnetic field whose electric cross-spectral density tensor is proportional to the imaginary part of the infinite-space Green tensor. Using the recently established electromagnetic theory of coherent modes, we construct, in a finite spherical volume, the coherent-mode representation of the random electromagnetic field having this property. The analysis covers the fundamental case of blackbody radiation but is valid more generally; since a thermal equilibrium condition is not invoked, the electromagnetic field may have any spectral distribution. Within the scalar theory of coherent modes, which has been available for more than two decades, the analogous formulation results in the first explicit three-dimensional coherent-mode representation.

Journal Article↗
PubMed2002

[In the consumers' interest: precautionary principles for protection against electromagnetic fields].

The considerable increase in using mobile communication which will increase when new technologies, such as UMTS, are introduced has resulted in further public interest concerning the possible health risks from electromagnetic fields of cellular phone networks. In view of evaluating the scientific state-of-the art, it has been shown that based on the available scientific results, the individual risk in view of proved health consequences is considered low. There are, however, indications of biological effects of high-frequency electromagnetic fields, even at intensities below the currently applied limit values or recommendations for limit values. Although the health relevance of these effects is still unclear, they give reason to precautionary measures with the object to minimise possible health risks which might affect a large number of persons. The precautionary measures recommended by the Federal Office for Radiation Protection include three principles: 1. Exposure of the general public to electromagnetic fields should be as low as possible. This applies for both the fixed parts of cellular phone networks and for mobile phones. 2. The population should be informed of risks in an objective and comprehensive way and be involved in the decisions on the construction and operation of cellular phone networks. 3. Scientific uncertainties should be reduced by means of well-directed research programmes. These precautionary measures and the significance of limit values are explained below.

Cell Phone↗
PubMed1993

A double-blind trial of the clinical effects of pulsed electromagnetic fields in osteoarthritis.

OBJECTIVE: Further evaluation of pulsed electromagnetic fields (PEMF), which have been observed to produce numerous biological effects, and have been used to treat delayed union fractures for over a decade. METHODS: In a pilot, double-blind randomized trial, 27 patients with osteoarthritis (OA), primarily of the knee, were treated with PEMF. Treatment consisted of 18 half-hour periods of exposure over about 1 month in a specially designed noncontact, air-coil device. Observations were made on 6 clinical variables at baseline, midpoint of therapy, end of treatment and one month later; 25 patients completed treatment. RESULTS: An average improvement of 23-61% occurred in the clinical variables observed with active treatment, while 2 to 18% improvement was observed in these variables in placebo treated control patients. No toxicity was observed. CONCLUSION: The decreased pain and improved functional performance of treated patients suggests that this configuration of PEMF has potential as an effective method of improving symptoms in patients with OA. This method warrants further clinical investigation.

Double-Blind Method↗
PubMed1985

Effects of pulsed electromagnetic field on growth and differentiation of embryonal carcinoma cells.

A murine embryonal carcinoma cell line (F9) was used to examine the effect of a pulsed electromagnetic field on the growth and differentiation of malignant cells. The cells can be induced to differentiate into parietal endodermal cells by treatment with retinoic acid. The pulsed electromagnetic field (1 Gauss and 10 Gauss) promoted the growth of embryonal carcinoma cells in both the presence and absence of retinoic acid. The pulsed electromagnetic field was also found to inhibit retinoic acid-induced differentiation, when the degree of differentiation was based on morphological criteria or on the production of plasminogen activator.

Animals↗
PubMed1989

The remedial electromagnetic field.

This paper reviews the history and development of electric and electromagnetic fields used in the treatment of a variety of medical conditions. An account is given of their clinical use and some suggestions are advanced for an explanation of a possible physiological mechanism.

Bone Diseases↗
PubMed1991

Occupational exposure to electromagnetic fields and breast cancer in men.

Data from a population-based case-control study of breast cancer in men were used to examine the hypothesis that occupational exposure to electromagnetic fields increases the risk of breast cancer. Incident cases (n = 227) diagnosed between 1983 and 1987 were obtained from 10 population-based cancer registries of the Surveillance, Epidemiology, and End Results program of the National Cancer Institute. Controls (n = 300) were selected by random digit dialing and from Medicare eligibility lists. Exposure status, defined as ever having been employed in a job which has been classified as involving potential exposure to electromagnetic fields, was assigned without knowledge of case/control status. An elevated risk was found for any job with exposure (odds ratio (OR) = 1.8, 95 percent confidence interval (CI) 1.0-3.7), and risk was highest among electricians, telephone linemen, and electric power workers (OR = 6.0, 95 percent CI 1.7-21) and radio and communications workers (OR = 2.9, 95 percent CI 0.8-10). Risk did not vary with duration of exposed employment. The risk was highest among subjects who were first employed in jobs with exposure before the age of 30 years and who were initially exposed at least 30 years prior to diagnosis. These results lend support to the theory that electromagnetic fields may be related to breast cancer in men. The hypothesis warrants evaluation in women.

Adult↗
PubMed1986

Mitogen dose-dependent effect of weak pulsed electromagnetic field on lymphocyte blastogenesis.

The effects of pulsed extremely low frequency electromagnetic fields on human peripheral blood lymphocyte mitogenesis induced by phytohaemoagglutinin, concanavalin A or calcium ionophore A23187 were studied. The dependence of the field effect on mitogen concentrations was investigated. Field exposure produced strong inhibition of DNA synthesis when optimal doses of mitogens were used, confirming our previous findings. Opposite effects were observed at suboptimal concentration of mitogens. Experiments performed by exposing cell cultures to the field for short periods indicated that a field application of at least 6 h is needed to influence irreversibly lymphocyte blastogenesis.

Calcimycin↗
PubMed1990

Bone density changes in osteoporosis-prone women exposed to pulsed electromagnetic fields (PEMFs).

To determine the effect of a 72 Hz pulsating electromagnetic field (PEMF) on bone density of the radii of osteoporosis-prone women, the nondominant forearms of 20 subjects were exposed to PEMF 10 h daily for a period of 12 weeks. Bone density before, during, and after the exposure period was determined by use of a Norland-Cameron bone mineral analyzer. Bone mineral densities of the treated radii measured by single-photon densitometry increased significantly in the immediate area of the field during the exposure period and decreased during the following 36 weeks. A similar but weaker response occurred in the opposite arm, suggesting a "cross-talk" effect on the nontreated radii, from either possible arm proximity during sleep or very weak general field effects. The data suggest that properly applied PEMFs, if scaled for whole-body use, may have clinical application in the prevention and treatment of osteoporosis.

Aged↗
PubMed1995

Effects of electromagnetic fields on molecules and cells.

Evidence suggests that cell processes can be influenced by weak electromagnetic fields (EMFs). EMFs appear to represent a global interference or stress to which a cell can adapt without catastrophic consequences. There may be exceptions to this observation, however, such as the putative role of EMFs as promoters in the presence of a primary tumor initiator. The nature of the response suggests that the cell is viewing EMFs as it would another subtle environmental change. The age and state of the cell can profoundly affect the EMF bioresponse. There is no evidence that direct posttranscription effects occur as a result of EMF exposure. Although transcription alterations occur, no apparent disruption in routine physiological processes such as growth and division is immediately evident. What is usually observed is a transient perturbation followed by an adjustment by the normal homeostatic machinery of the cells. DNA does not appear to be significantly altered by EMF. If EMF exposure is associated with an increased risk of cancer, the paucity of genotoxic effects would support the suggestion that the fields act in tumor promotion rather than initiation. The site(s) and mechanisms of interaction remain to be elaborated. Although there are numerous studies and hypotheses that suggest the membrane represents the primary site of interaction, there are also several different studies showing that in vitro systems, including cell-free systems, are responsive to EMFs. The debate about potential hazards or therapeutic value of weak electromagnetic fields will continue until the mechanism of interaction has been clarified.

Animals↗
PubMed1990

Paternal occupational exposure to electromagnetic fields and neuroblastoma in offspring.

Investigators in Texas have reported an association between paternal employment in jobs linked with exposure to electromagnetic fields and risk of neuroblastoma in offspring. In an attempt to replicate this finding, the authors conducted a case-control study in Ohio. A total of 101 incident cases of neuroblastoma were identified through the Columbus (Ohio) Children's Hospital Tumor Registry. All cases were born sometime during the period 1942-1967. From a statewide roster of birth certificates, four controls were selected for each case, with individual matching on the case's year of birth, race, and sex, and the mother's county of residence at the time of the (index) child's birth. Multiple definitions were employed to infer the potential for paternal occupational exposure to electromagnetic fields from the industry/occupation statements on the birth certificates. Case-control comparisons revealed adjusted odds ratios ranging in magnitude from 0.5 to 1.9. For two of the exposure definitions employed--both of which are similar to one used by the Texas investigators--the corresponding odds ratios were modestly elevated (odds ratios = 1.6 and 1.9). Notably, the magnitude of these odds ratios is not inconsistent with the Texas findings, where the exposure definition referred to yielded an odds ratio of 2.1. Because the point estimates in this study are imprecise, and because the biologic plausibility of the association is uncertain, the results reported here must be interpreted cautiously. However, the apparent consistency between two independent studies suggests that future evaluation of the association is warranted.

Adolescent↗