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PubMed1996

[Exposure to low electromagnetic fields and the carcinogenesis process].

In the literature as well as in public media increasing attention is paid to possible health effects of exposure to low-frequency electric and magnetic fields, Experimental studies at the cellular level and mammalian studies in vivo have demonstrated various biological effects that are possibly associated with human exposure to low-frequency radiation. Although the exact mechanism of this relationship is not entirely clear, it has been indicated that low-frequency radiation might promote the process of carcinogenesis, although it does not seem likely to initiate it. A possible link between human low-frequency exposure and occurrence of carcinoma at child and adult age has been examined in some fifty epidemiological studies. A few studies have demonstrated a possible connection between carcinoma at child age and distance from electrical installations. Although the results point to an association between exposure to low-frequency electric and magnetic fields and cancer, further research is called for. In the meantime "cautious avoidance" of extended exposure to low-frequency electromagnetic fields is recommended.

Animals↗

PubMed2000

Exposure to low-frequency electromagnetic fields does not alter HSP70 expression or HSF-HSE binding in HL60 cells.

Environmental exposure to extremely low-frequency electromagnetic fields (ELF EMFs) has been identified as a possible contributor to increased cancer incidence and other diseases. In vitro studies designed to probe for biological mechanisms that might explain such relationships have included several studies of gene expression. While gene expression studies have focused on MYC, effects of ELF EMFs on the expression of beta-actin, histone H2B, beta-tubulin, SRC, FOS and JUN have also been reported. In addition, some investigators have reported both an induction of HSP70 expression and an increase in HSF-HSE binding in HL60 (human promyelocytic leukemia) cells after exposure to a 60 Hz magnetic field. In this study, HL60 cells were exposed to a weak 60 Hz magnetic field (6.3 or 8.0 microT) or to a positive control heat shock (42 or 44 degrees C). While heat shock led to reproducible induction of HSP70 expression and HSF-HSE binding, no significant effect of exposure to ELF EMFs on either of these end points was observed.

Blotting, Northern↗

PubMedDate not supplied

[Influence of low frequency electromagnetic fields on the nervous system].

The methods present a short review of the literature dealing with non-thermal bioeffect of electromagnetic fields (EMF), mainly of low and extremely low frequency. The main attention is paid to the information about disorders of the nervous system and about epidemiologic studies of brain tumors in the population exposed to EMF. All quoted authors have stressed great difficulties in the right assessment of adverse effects due to EMF's because of their non-specific influence on the biological structures.

Brain Neoplasms↗

PubMedDate not supplied

[The effect of electromagnetic field on the biosynthesis and various properties of extracellular proteinase and lectin from Bacillus subtilis 316 M].

The promoting effect of electromagnetic field (EMF) on biosynthesis and activity of extracellular proteinase and lectin in B. subtilis 316 M was observed. It caused 1.5- and 4-fold increase of the metabolites yield respectively. The EMF stimulated a 2-fold activation of lectin, rise of the enzyme activity and a shift of it pI from 11.4-11.5 to 9.2-9.3.

Bacillus subtilis↗

PubMed1997

Exposure to extremely-low-frequency electromagnetic fields and radiofrequency radiation: cardiovascular effects in humans.

Cardiovascular changes in humans exposed to nonionizing radiation [including extremely-low-frequency electromagnetic fields (ELF EMFs) and radiofrequency radiation (RFR)] are reviewed. Both acute and long-term effects have been investigated. In general, if heating does not occur during exposure, current flow appears to be necessary for major cardiovascular effects to ensue, such as those due to electric shock. Whereas most studies have revealed no acute effect of static or time-varying ELF EMFs on the blood pressure, heart rate, or electrocardiogram waveform, others have reported subtle effects on the heart rate. The possible health consequences of these results are unknown. Regarding long-term effects of ELF EMFs, reports from the former Soviet Union in the early 1960s indicated arrhythmias and tachycardia in high-voltage-switchyard workers. Subsequent studies in Western countries, however, did not confirm these findings. These studies are limited by uncertainties regarding exposure durations and appropriate control groups. Investigations of acute cardiovascular changes in humans purposely exposed to RFR have been limited to studies of magnetic resonance imaging (which, in addition to RFR, involves static and time-varying magnetic fields). It has been concluded that such exposures, as presently performed, are not likely to cause adverse cardiovascular effects. Reports of hypertension in workers potentially exposed to high levels of RFR during accidents are considered to be incidental (due to anxiety and posttraumatic stress). Soviet investigators have also indicated that long-term RFR exposure may result in hypotension and bradycardia or tachycardia. Other researchers, however, have been incapable of replicating these results, and some scientists have attributed the effects to chance variations and mishandling of data. In summary, studies have not yielded any obvious cardiovascular-related hazards of acute or long-term exposures to ELF EMFs or RFR at levels below current exposure standards.

Animals↗

PubMed2004

Effects of electromagnetic field emitted by cellular phones on the EEG during an auditory memory task: a double blind replication study.

The effects of electromagnetic fields (EMF) emitted by cellular phones on the event related desynchronization/synchronization (ERD/ERS) of the 4-6, 6-8, 8-10, and 10-12 Hz electroencephalogram (EEG) frequency bands were studied in 24 normal subjects performing an auditory memory task. This study was a systematic replication of our previous work. In the present double blind study, all subjects performed the memory task both with and without exposure to a digital 902 MHz field in a counterbalanced order. We were not able to replicate the findings from our earlier study. All eight of the significant changes in our earlier study were not significant in the present double blind replication. Also, the effect of EMF on the number of incorrect answers in the memory task was inconsistent. We previously reported no significant effect of EMF exposure on the number of incorrect answers in the memory task, but a significant increase in errors was observed in the present study. We conclude that EMF effects on the EEG and on the performance on memory tasks may be variable and not easily replicable for unknown reasons.

Adult↗

PubMed1993

Occupational exposure to electromagnetic fields in relation to leukemia and brain tumors: a case-control study in Sweden.

Occupational exposure to low-frequency electromagnetic fields (EMF) was studied in 250 leukemia patients and 261 brain-tumor cases, diagnosed in 1983-87 and compared with a control group of 1,121 randomly selected men, from the mid-region of Sweden, 1983-87. We based the exposure assessment on measurements from 1,015 different workplaces. On the basis of the job held longest during the 10-year period before diagnosis, we found an association between the average, daily, mean level of EMF and chronic lymphocytic leukemia (CLL). The risk increased with increasing level of exposure. The odds ratios (OR) and the 95 percent confidence interval (CI) for three consecutive levels of exposure were: 1.1 (CI = 0.5-2.3); 2.2 (CI = 1.1-4.3); 3.0 (CI = 1.6-5.8), respectively. No association was observed for acute myeloid leukemia (OR = 1.0, CI = 0.5-1.8; OR = 0.8, CI = 0.4-1.6; OR = 1.0, CI = 0.6-1.9). For brain tumors, the corresponding risk estimates were 1.0 (CI = 0.7-1.6); 1.5 (CI = 1.0-2.2); 1.4 (CI = 0.9-2.1). Different EMF indices were tested. Tasks with frequent or large variations between high and low field-densities (high standard deviation) were more common among CLL subjects. For brain tumors, a prolonged high level (high median values) showed the strongest association. Confounding by place of residence, smoking, benzene, ionizing radiation, pesticides, and solvents was evaluated, and these factors did not seem to have a decisive influence on the associations. We also analyzed other potential sources of bias. For CLL, there were indications of an excess number of low-exposure subjects among non-responders, which, to some extent, may have enhanced but not caused the risk estimates obtained. Our conclusion is that the study supports the hypothesis that occupational EMF exposure is a hazard in the development of certain cancers.

Acute Disease↗

PubMed1994

Association between exposure to pulsed electromagnetic fields and cancer in electric utility workers in Quebec, Canada, and France.

The authors report the association between exposure to pulsed electromagnetic fields (PEMFs) and cancer in a nested case-control study of electric utility workers in Quebec, Canada (follow-up, 1970-1988), and France (follow-up, 1978-1989), among whom 2,679 cases of cancer were identified. Exposures were assessed through a job-exposure matrix based on about 1,000 person-weeks of measurements from exposure meters worn by workers. Exposures were considerably higher in Quebec than in France. No association was found between PEMFs and cancers previously suspected of association with magnetic fields (leukemia, other hematopoietic cancers, brain cancer, or melanoma). However, there was a clear association between cumulative exposure to PEMFs and lung cancer, with odds ratios rising to 3.11 (95% confidence interval (CI) 1.60-6.04) in the highest exposure group (84 cases). This association with largely confined to Quebec, where there was a monotonic exposure-response relation with an odds ratio of 6.67 (95% CI 2.68-16.57) in the highest exposure group (32 cases). The association is substantial and was not explained by smoking or other occupational exposures. However, several factors limit the strength of the evidence for a causal relation: lack of precision in what the meters measured; little previous evidence for this association; and no elevated risk for lung cancer in the utility workers overall in comparison with the general population.

Case-Control Studies↗

PubMed2004

[Effect of 900MHz electromagnetic fields on energy metabolism of cerebral cortical neurons in postnatal rat].

OBJECTIVE: To investigate the effects of low intensity microwave (900MHz) electromagnetic fields (EMF) on energy metabolism of cerebral cortical neurons in postnatal rat. METHODS: Neurons were exposed to low intensity 900MHz continuous microwave EMF (9mW/cm2, SAR = 3.22mW/g) for 2 hours per day in 4 or 5 consecutive days and for 12 hours at a time. The authors chose cytochrome oxidase (CCO) as the biological end. RESULTS: The results of cytochemistry showed that compared to the sham-exposed, a significant decrease of cytochrome oxidase activity in neurons exposed for 2 hours per day and the neurons exposed for 12 hours to be immediately experimented (P < 0.001). CONCLUSION: Down-regulation of CCO should be classified as 'non-thermal effects'. Cumulated power effect were observed in neuronal response to the microwave. The influence on the CCO of the chosen microwave EMF could be recovered to some extent. The effects had no close relation between the first exposure and the cultured age of neurons.

Animals↗

PubMed1990

Incidence of leukemia in occupations with potential electromagnetic field exposure in United States Navy personnel.

Leukemia is the fourth most commonly occurring cancer in the United States population between the ages of 17 and 34 years, an age group heavily represented in the US Navy. Historical computerized military career records maintained at the Naval Health Research Center, San Diego, California, were used to determine person-years at risk (total, 4,072,502 person-years) by demographic characteristics and occupation for active-duty naval personnel during 1974-1984. Computerized inpatient medical records were searched for first hospitalizations for leukemia. Cases of leukemia (n = 102) were verified by using pathology reports or Navy Medical Board or Physical Evaluation Board findings. For comparisons, age-adjusted incidence rates and standardized incidence ratios were calculated by using rates for the US population provided by the Surveillance, Epidemiology, and End Results program of the National Cancer Institute. The overall age-adjusted incidence rate of leukemia in active-duty naval personnel was found to be very close to that of the Surveillance, Epidemiology, and End Results program population (6.0 vs. 6.5 per 100,000 person-years). Only one occupation, electrician's mate, emerged with a borderline statistically significant excess risk of leukemia (standardized incidence ratio compared with the Surveillance, Epidemiology, and End Results program population = 2.4, 95% confidence interval 1.0-5.0). This finding is intriguing in the light of several studies showing an excess risk of leukemia associated with exposure to electromagnetic fields.

Adolescent↗

PubMedDate not supplied

[Changes in the functional state of rat liver and kidney mitochondria under the effect of electromagnetic fields].

Oxidative phosphorylation and optical density of the rat liver and kidney mitochondria were studied under the effect of UHF and SHF electromagnetic fields of different power and duration of the action. It is established that a single action of these fields induces changes in the functional state of the mitochondria. The action by the UHF and SHF fields of 30W for 10 min increases the activity of respiration and phosphorylation in the liver and kidney mitochondria. The actions of the SHF electric field of 50 and 50W and UHF fields of 80W induce the splitting of oxidation phosphoryation, in the mitochondria. In this case there arise a considerable swelling of the mitochondria, which is evidenced by a decrease in their optic density.

Animals↗

PubMed2002

Effects of pulsed electromagnetic field (PEMF) stimulation on bone tissue like formation are dependent on the maturation stages of the osteoblasts.

The effects of pulsed electromagnetic field (PEMF, 15 Hz pulse burst, 7 mT peak) stimulation on bone tissue-like formation on osteoblasts (MC3T3-E1 cell line) in different stages of maturation were assessed to determine whether the PEMF stimulatory effect on bone tissue-like formation was associated with the increase in the number of cells and/or with the enhancement of the cellular differentiation. The cellular proliferation (DNA content), differentiation (alkaline phosphatase activity), and bone tissue-like formation (area of mineralized matrix) were determined at different time points. PEMF treatment of osteoblasts in the active proliferation stage accelerated cellular proliferation, enhanced cellular differentiation, and increased bone tissue-like formation. PEMF treatment of osteoblasts in the differentiation stage enhanced cellular differentiation and increased bone tissue-like formation. PEMF treatment of osteoblasts in the mineralization stage decreased bone tissue-like formation. In conclusion, PEMF had a stimulatory effect on the osteoblasts in the early stages of culture, which increased bone tissue-like formation. This stimulatory effect was most likely associated with enhancement of the cellular differentiation, but not with the increase in the number of cells.

3T3 Cells↗

PubMed2000

Behavior of free-ranging and captive American kestrels under electromagnetic fields.

Wild birds, particularly raptors, commonly use electrical transmission structures for nesting, perching, hunting, and roosting. Consequently, birds are exposed to electromagnetic fields (EMFs). The amount of time that wild reproducing American kestrels (Falco sparverius) were exposed to EMFs was determined, and the effects of EMFs on the behavior of captive reproducing kestrels were examined. Wild kestrels were exposed to EMFs for 25% to 75% of the observed time. On a 24-h basis, estimated EMF exposure of wild kestrels ranged from 71% during courtship, to 90% during incubation, similar to that experienced by captive kestrels (88% of a 24-h period). Additionally, captive kestrels were exposed to EMF levels experienced by wild kestrels nesting under 735-kV power lines. Captive EMF females were more active, more alert, and perched on the pen roof more frequently than control females during courtship. EMF females preened and rested less often during brood rearing. EMF male kestrels were more active than control males during courtship, and more alert during incubation. Increased activity of kestrels during courtship may be linked to changes in corticosterone, but likely not melatonin. Observed behavioral changes were unlikely to directly result in the better growth of nestlings and fledging success, or poorer hatching success, of the EMF group, as previously reported. Behavioral changes of captive EMF kestrels may be observed in wild kestrels.

Animals↗

PubMed2006

Effect of extremely low frequency electromagnetic fields (ELF-EMF) on Kaposi's sarcoma-associated herpes virus in BCBL-1 cells.

Association between extremely low frequency electromagnetic fields (ELF-EMF) and human cancers is controversial, and few studies have been conducted on their influence on oncogenic viruses. We studied the effects of 1 mT, 50 Hz sine waves, applied for 24-72 h, on Kaposi's sarcoma (KS)-associated herpesvirus (KSHV or HHV-8) in BCBL-1, a latently infected primary effusion lymphoma (PEL) cell line. ELF-EMF exposure did not affect the growth and viability of BCBL-1 cells, either stimulated or not with TPA. The total amount of KSHV DNA detected in ELF-EMF exposed cultures not stimulated with TPA did not differ from that of the unexposed controls (P = ns). However, in the presence of TPA stimulation, total KSHV DNA content was found higher in ELF-EMF exposed than in control BCBL-1 cultures (P = .024) at 72 h exposure, but not earlier. Viral DNA increase significantly correlated with increased mean fluorescence intensity/cell for the lytic antigen gp K8.1A/B (P < .01), but not with percentage of gp K8.1A/B-positive cells or of cells containing virions. Viral progeny produced under ELF-EMF exposure consisted mainly of defective viral particles.

Cell Line, Tumor↗

PubMed1991

Long-term pulsed electromagnetic field (PEMF) results in congenital pseudarthrosis.

Ninety-one patients with congenital pseudarthrosis of the tibia have been treated with pulsed electromagnetic fields (PEMFs) since 1973 and all except 4 followed to puberty. Lesions were stratified by roentgenographic appearance. Type I and type II had gaps less than 5 mm in width. Type III were atrophic, spindled, and had gaps in excess of 5 mm. Overall success in type I and II lesions was 43 of 60 (72%). Of those 28 patients seen before operative repair had been attempted, 7 of 8 type I lesions healed (88%), whereas 16 of 20 type II lesions healed (80%) on PEMFs and immobilization alone. Only 19% (6 of 31) type III lesions united, only one of which did not require surgery. Sixteen of 91 limbs (18%) were ultimately amputed, most before treatment principles were fully defined in 1980. Fourteen of these 16 patients (88%) had type III lesions. Refracture occurred in 22 patients, most as the result of significant trauma, in the absence of external brace support. Twelve of the 19 refractures, retreated with PEMFs and casts, healed on this regime. Episodic use of PEMFs proved effective in controlling stress fractures in several patients until they reached puberty. PEMFs, which are associated with no known risk, appear to be an effective, conservative adjunct in the management of this therapeutically challenging, congenital lesions.

Adolescent↗

PubMed2000

Evaluation of the effects of extremely low frequency electromagnetic fields on mammalian follicle development.

The aim of this study was to evaluate the effects of pulsed, extremely low-frequency electromagnetic fields (ELF-EMF) on in-vitro mouse pre-antral follicle development. Pre-antral follicles were cultured for 5 days and exposed to ELF-EMF at the frequencies of 33 or 50 Hz. ELF-EMF application did not affect follicular growth over a 3 day culture period, but on day 5 the growth of 33 Hz-exposed follicles was significantly reduced when compared with controls, while the 50 Hz-exposed follicles were not significantly affected. However, ELF-EMF severely impaired antrum formation at both frequencies, as 79 +/- 3% of control follicles developed antral cavities compared with 30 +/- 6% and 51.6 +/- 4% of 33 or 50 Hz-exposed follicles respectively. The follicles with failed antrum formation showed lower oestradiol release and granulosa cell DNA synthesis, but these effects were not related to granulosa cell apoptosis. Furthermore, a high percentage of the in-vitro grown oocytes obtained from exposed follicles had a reduced ability to resume meiotic maturation when compared with controls. These results suggest that ELF-EMF exposure might impair mammalian female reproductive potentiality by reducing the capacity of the follicles to reach a developmental stage that is an essential pre-requisite for reproductive success.

Animals↗

PubMed2003

Study of extremely low frequency electromagnetic fields in infant incubators.

OBJECTIVES: The aim of the work was to present the results of measurements of extremely low frequency electromagnetic fields (ELF EMF), namely the magnetic flux density, inside infant incubators, and to compare these results with the data published by other authors who point out to a possible association between leukemia or other diseases observed in newborns kept in incubators after the birth and the ELF EMF exposure in the incubator. The measured magnetic flux densities were compared with the reference values for this frequency range indicated in the European Union (EU) recommendations. MATERIALS AND METHODS: The repeated measurements in incubators were made with a calibrated magnetometer EFA 300 in the frequency range of 5-30 kHz. Effective values of magnetic flux densities of ELF EMF were determined taking account of the reference values. RESULTS: The results of many repeated measurements showing the values of magnetic flux density in modern incubators with plastic supporting frame, were compared with those obtained in old type incubators with iron skeleton. A power frequency of 50 Hz was detected in the incubator and the ELF EMF values were by over two orders lower than the EU reference values. CONCLUSIONS: The paper emphasizes the need to take a special care of newborns kept in incubators even if only the sub-reference values are detected. The EU reference values are intended for the adult human population. A baby in an incubator has much smaller dimensions, higher electric conductivity and maybe trigger another mechanism of response to ELF EMF than that indicated in this paper.

Electromagnetic Fields↗

PubMed2001

Electromagnetic field effects: changes in protein phosphorylation in the Jurkat E6.1 cell line.

This study is aimed at expanding the role of electromagnetic field (EMF) therapy for treatment of inflammatory diseases and obtaining new information on the biophysical mechanism of action of weak EMFs. The mechanism of action of EMFs on biological systems is a question that has yet to be answered. Several models have been proposed to explain the coupling of low frequency fields to biological systems, although no consensus has been reached as to which most adequately portrays the true mechanism. Protein phosphorylation is a major cellular metabolic regulator. As such, it has the potential to be a valuable indicator of the impact of EMFs on cellular metabolism. Using a well-controlled EMF exposure system, we examined the regulatory role of EMFs on low molecular weight protein phosphorylation in Jurkat E6.1 cells, a transformed human leukemic T cell line. Jurkat cells were grown to mid-log phase, preloaded with 32P and exposed to EMF (0.1 mT, 60 Hz) or sham for 30 minutes. Cell proteins were separated by SDS-polyacrylamide gel electrophoresis and incorporated radioactivity of low molecular weight proteins (18-23 kDa) was quantified by AMBIS data analysis. Three of five experiments showed no difference in protein phosphorylation in EMF exposed samples compared to controls, while two experiments revealed an EMF effect. We identified stathmin, an important T cell signaling phosphoprotein, as one of the low molecular weight proteins present in our Jurkat cell system. Stathmin expression as well as its phosphorylation was decreased in samples that were exposed to EMFs compared to controls. These data indicate that phosphorylation of individual proteins might be masked by the presence of numerous other proteins in whole cell lysate experiments. Further studies testing other low molecular weight T cell signaling molecules may validate this hypothesis.

Cells, Cultured↗