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PubMed2006

[Electromagnetic fields measurements to assess workers' exposure and environmental protection: interlaboratory comparisons].

Interlaboratory comparisons (ILC) are an important element of quality systems of certified testing laboratories. It is the policy of the majority of certifying institutions to participate in ILC programs concerning research laboratories. ILC programs are technical initiatives. An analysis of the ILC results allows for taking decisive actions-proficiency testing. There are many types of ILC. However, in EMF measurements, the result comparison programs are usually applied. All program participants measure the same EMF source, usually the one that is normally exploited. The authors present the results and analysis of interlaboratory comparisons performed by certified laboratories. Comparisons presented in the paper were performed in the vicinity of the GSM base station.

Clinical Laboratory Techniques↗
PubMed2003

Age-related effects on induction of DNA strand breaks by intermittent exposure to electromagnetic fields.

Several studies indicating a decline of DNA repair efficiency with age raise the question, if senescence per se leads to a higher susceptibility to DNA damage upon environmental exposures. Cultured fibroblasts of six healthy donors of different age exposed to intermittent ELF-EMF (50 Hz sinus, 1 mT) for 1-24 h exhibited different basal DNA strand break levels correlating with age. The cells revealed a maximum response at 15-19 h of exposure. This response was clearly more pronounced in cells from older donors, which could point to an age-related decrease of DNA repair efficiency of ELF-EMF induced DNA strand breaks.

Adolescent↗
PubMedDate not supplied

[The contingency of the parameters of the human brain electroencephalograms and electromagnetic fields of the Schuman resonator based on monitoring studies].

The contingency of the variations in the amplitude frequency parameters of the main modes of extremely-low-frequency resonances ionosphere waveguide (Shuman resonances) and changes in the parameters of human electroencephalograms in the range of the frequency "window" (6-16 Hz) was studied. The results of studies in the regimes of synchronized monitoring suggest that the contingency of the parameters of electroencephalograms and extremely-low-frequency resonances, expressed in the parameters of the cross-correlation function, is statistically significant and varies from 0.12 to 0.65 at alpha = 0.95. It was found that the magnitude of contingency is largely the function of the current value of the solar and geomagnetic activity.

Adult↗
PubMed2003

Mouse early embryos obtained by natural breeding or in vitro fertilization display a differential sensitivity to extremely low-frequency electromagnetic fields.

We have investigated the sensitivity of pre-implantation embryos obtained by natural breeding (NB) or in vitro fertilization (IVF) to extremely low-frequency magnetic fields (ELF-MF). Fertilized eggs obtained by NB were removed from mothers 12h after mating and cultured in vitro for 5 days under continuous ELF-MF exposure (constant strength of 50Hz and various intensities, i.e. 60, 120 and 220 microT). Alternatively, zygotes obtained by IVF were subjected to ELF-MF exposure (50Hz, 60 microT), starting 12h after IVF for 5 days. We found that ELF-MF exposure causes a small yet significant (P<0.05) decrease in the survival rate of NB-derived embryos at the latest stages of pre-implantation development, i.e. the eight cell-to-blastocyst transition. In embryos exposed to the highest field intensity (220 microT), the effect became apparent somewhat earlier. When IVF-derived embryos were exposed to ELF-MF, the reduction in the rate of embryo survival was more pronounced and the difference from controls was more significant (P<0.01). Moreover, the decreased survival rate in IVF embryos became apparent as early as the first cleavage and persisted throughout pre-implantation. These results suggest that IVF-derived embryos are more sensitive than NB-generated embryos to ELF-MF, and that this sensitivity occurs earlier in development.

Animals↗
PubMed1999

Absence of synergistic effects on micronucleus formation after exposure to electromagnetic fields and asbestos fibers in vitro.

Exposure of human amniotic fluid (AFC) cells to horizontally applied magnetic fields (hMF) of 50 Hz and 1 mT generated in a Helmholtz-coil system leads to a significant increase in micronucleus frequency (MN), without affecting cell proliferation. To investigate whether hMF-exposure has an additive or synergistic effect on the genotoxic capacity of asbestos fibers, MN induction was investigated in hMF pre-exposed cells, treated before or after with asbestos (1 microg/cm2). Neither synergistic nor additive effects on MN induction were observed. The results indicate, that under our experimental conditions, exposure to hMF and treatment with asbestos fibers possess genotoxic capability, but no interactive effects, in AFC cells.

Amniotic Fluid↗
PubMed2006

Decibel attenuation of pulsed electromagnetic field (PEMF) in blood and cortical bone determined experimentally and from the theory of ohmic losses.

We studied the PEMF power attenuation in tissues representative of clinical applications (blood and cortical bone) to determine the amount of power available for PEMF purported biological effects. The experimental system consisted of a pair of nearly circular, parallel and coaxial coils separated by a distance of one coil diameter. The power attenuation was measured using a small search coil connected to a digital oscilloscope. The coils were powered by a voltage switch operating at two different frequencies (3.8 and 63 kHz) producing bursts of pulses (numbering 21 and 1619) and triggered at two different frequencies (1.5 and 15 Hz, respectively). The tissue samples were placed inside the coils so as to expose them to either transverse electric field (at the center of coils) or the transverse magnetic field (at the coil wire). The cylindrical coil geometry yielded closed-form expressions for power attenuation based on magnetic diffusion equation and ohmic losses due to bulk tissue magnetic permeability and electrical conductivity. The measured power attenuation at these PEMF frequencies of not more than one decibel (1 dB) was well explained by the theory for the 3.8 kHz but less so for the 63 kHz frequency PEMF. The results provide important insights regarding physical mechanism of weak PEMF power dissipation in tissues.

Animals↗
PubMedDate not supplied

[Influence of (460 MHz) electromagnetic fields on the induced lipid peroxidation in the structures of visual analyzer and hypothalamus in experimental animals].

Changes in the intensity of ascorbate- and NADPN2-dependent induced lipid peroxidation (LPO) were studied in exposure of the visual analyzer and hypothalamus of 3- and 12-month-old rats to radiation with microwaves of high and low intensity. The exposure to microwaves of high intensity stimulated basal LPO but suppressed activity of LPO-inducing systems. This suggests disturbances in the activity of different sources of active oxygen forms. Microwaves of low intensity activated systems of induced LPO. This is accompanied with synchronous activity of the antioxidant defense system maintaining a normal oxidation-reduction balance of the cell. The conclusion is that, depending on their intensity, microwaves can be either beneficial to health or be a factor of oxidative stress.

Animals↗
PubMed1990

[Effect of pulsating electromagnetic field therapy on cell volume and phagocytosis activity in multiple sclerosis and migraine].

PEMF treatment was studied in 10 patients with multiple sclerosis and 10 patients with migraine. In both patients' groups a single treatment induced a significant rise of yeast particle uptake by blood granulocytes. The percentage of phagocytizing cells was increased in migraine patients only. In both patients' groups 20 PEMF treatments caused a reduction of particle uptake, whereas the percentage of phagocytizing cells remained unchanged. In migraine patients the opsonic capacity of serum and the mean cell volume of erythrocytes, lymphocytes and granulocytes were initially reduced, but increased during the course of 20 PEMF treatments. The biphasic changes of cell volume and phagocytic activity are interpreted as a result of counter-regulation of the organism in response to the primary PEMF effect.

Electromagnetic Fields↗
PubMedDate not supplied

[The effect of weak electromagnetic fields and ionizing radiation on the regeneration of the murine sciatic nerve].

The influence of X-ray impulses (dose 0.003 cGy, longitudity 10 ns) and EM impulses (induction 0.003 mT) on sciatic nerve regeneration in mice after crush lesion was studied. Limb jerk amplitude at electric stimulation of nerve and postural reflex in thin rod in X + EM and EM groups were restored within 13th days after lesion, in control group within 15 days (p < 0.05). The beginning of repairing of postural reflex was early in X + EM group than on EM group, rehabilitation of limb jerk amplitude--in EM group. Histological examination demonstrated that myelin degenerated in EM group more rapidly as compared with X + EM and control groups. This data suppose different effects of EM and X + EM impulses on nerve-regenerating processes.

Animals↗
PubMed1998

Luciferase activity and synthesis of Hsp70 and Hsp90 are insensitive to 50Hz electromagnetic fields.

The activity of luciferase expressed in transfected 34i cells has been monitored under 50Hz EMF and heat shock. While heat shock decreased the luciferase activity, short exposure to EMFs did not, the luciferase expressed in cells exposed to EMFs at 300-3000 microT showing the same activity as that of control cells. To further analyse whether EMF and thermal stress display similar effects, the relative rate of Hsp90 and Hsp70 synthesis was investigated. Hsp90 and Hsp70 synthesis, while induced by a short thermal stress, was not increased by EMF exposure. These results, contrary to previously proposed similarities between thermal stress and EMF effects at a cellular level, indicate that protein denaturation and misfolding caused by thermal stress and responsible both for a loss of luciferase activity and for an induction of Hsp, are not necessarily induced by exposure to EMFs.

Animals↗
PubMed2004

Determinants of exposure to electromagnetic fields from mobile phones.

In actual conditions of use, the power radiated from cellular phones changes during conversation depending on several factors. Upon request from the radio base station (RBS), the phone in fact, reduces, its power to a level that is deemed optimum for the quality of conversation. In this study, special phones, which had been modified to allow the continuous logging of power emitted during the calls have been used. Off-line processing of recorded data allowed the analysis of the behaviour of mobile phones under real-use conditions. Further data recorded by operators at selected base stations were used for the purposes of comparison and checking of the effectiveness of the experimental method. The results indicate a high proportion of use of the highest power levels, under any circumstance. Such behaviour is mainly due to frequent handovers requested by the control software to optimise the communication traffic.

Body Burden↗
PubMed2003

Health risks of electromagnetic fields. Part I: Evaluation and assessment of electric and magnetic fields.

Exposure to electric and magnetic fields (EMF) emanating from the generation, distribution, and utilization of electricity is widespread. The major debate in recent years has focused on the possibility that exposure to EMF may result in adverse health consequences, including the development of cancer. This article provides a review and evaluation of potential health risks associated with residential and occupational exposure to EMF. In addition to reviewing data from laboratory, epidemiology, and clinical studies, we examine exposure data from field measurement surveys and exposure guidelines that have been established for EMF. Currently, the evidence in support of an association between EMF and childhood cancer is limited, although this issue warrants further investigation. Evidence of an association between EMF exposure and adult cancers, derived largely from occupational settings, is inconsistent, precluding clear conclusions. There is little evidence of an association between EMF and noncancer health effects. Epidemiological studies of EMF and population health are limited by exposure measurement error and the lack of a clear dose/response relationship in studies suggesting possible health risks. Further research is needed to clarify the ambiguous findings from present studies and to determine if EMF exposure poses a health risk.

Animals↗
PubMed1998

Mammary tumours in Sprague-Dawley rats after initiation with DMBA followed by exposure to 50 Hz electromagnetic fields in a promotional scheme.

In order to test whether a transient-producing intermittent magnetic field (MF) acts as a promoter in rat mammary tumour development, a study of a 50 Hz sinusoidal MF with flux densities of 0.25 and 0.5 mT was performed on female Sprague-Dawley rats. A single administration of 7 mg of 7,12-dimethyl-benz[a]anthracene (DMBA) was given by gavage to 52-day-old animals. After 1 week, exposure to an intermittent (15 s on/15 s off) transient-associated magnetic field was started. MF exposure was performed for 19 or 21 h per day up to 25 weeks, when the study was terminated. Twice a week a careful examination with palpation for tumours was done. Tumour incidence, the number of tumours per animal, tumour volume and tumour weight were recorded. A total of 70% of MF-exposed animals developed tumours. For animals exposed to DMBA alone the correspondent figure was 71.7%. No statistical differences were seen either for tumour-bearing animals or for the total number of tumours. A slightly larger total tumour weight and tumour volume was seen for animals exposed to 0.25 mT MF. These differences were not statistically significant.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1994

The question of health effects from exposure to electromagnetic fields.

Possible health effects of exposure to low-intensity electric and magnetic fields (EMFs) are receiving increased attention in the scientific literature and, especially, in the public media. Laboratory research at the cellular and whole animal level has demonstrated various biological effects that may be related in some manner to the effect of EMF exposure on people. However, the exact mechanisms of this relationship are far from clear. The studies suggest that EMFs might be cancer promoters but are unlikely to be cancer initiators. At the level of human epidemiology, approximately 50 studies have examined the possible correlation of EMF exposures with adult and childhood cancers. Although the possibility of a correlation is weak, it cannot be discounted, and further research is needed. In the meantime, a practice of "prudent avoidance" of prolonged exposure to EMFs is warranted.

Adult↗
PubMed1999

Electromagnetic field pattern in the environment of GSM base stations.

Three mobile phone systems are used in Poland: analog, operated at the 450 MHz frequency range, and two digital systems operated at 900 MHz and 1800 MHz. The GSM--Global System for Mobile Communication meets all relevant requirements, and it is most widely used throughout the world. According to the mobile phone concept, the whole communication area is divided into sub-areas (cells) where base stations are located. The base stations are provided with the transmitter units mounted on free-standing masts, high chimneys and building roofs, including those of the residential buildings. The transmitter antennas of the base stations constitute a source of 935-960 EMF radiation. This work analyses the essential characteristics of the base station antennas from the point of view of radiation intensity. The analysis is based on the results of EMF measurements performed by experts of two relevant research institutes. For inaccessible antennas, the measurements were performed at the accredited laboratory.

Electromagnetic Fields↗
PubMed1993

Chromosome aberrations in lymphocytes of high-voltage laboratory cable splicers exposed to electromagnetic fields.

Thirteen high-voltage laboratory employees and 20 referents participated in a cross-sectional, matched-pairs study of cytogenetic damage. During cable testing the workers were exposed to static, alternating, or pulsed electric and magnetic fields. The alternating magnetic field levels of 50 Hz were 5-10 microT, occasionally much higher. Chromosome aberrations, sister chromatid exchanges, and aneuploidy were studied in peripheral blood lymphocytes. In addition, chromosome aberrations were investigated in lymphocyte cultures treated with hydroxyurea and caffeine, to inhibit deoxyribonucleic acid synthesis and repair. Among seven smoking laboratory employees the mean number of chromosome breaks/200 cells was 2.3, as compared with 0.7 for the job-matched referents. The comparable figures for inhibited cultures were 12.0 versus 6.0. No increase was detected in nonsmokers with either method. The other genetic parameters showed no differences between the exposed workers and the referents. The results support, to some extent, the hypothesis of an increased risk of genotoxic effects among high-voltage laboratory workers.

Adult↗
PubMed1992

Incidence of cancer in Norwegian workers potentially exposed to electromagnetic fields.

The risk of cancer was investigated in a cohort of 37,945 male Norwegian electrical workers for whom information on job description was collected from 1960 census data and linked to the 1970 census data. The standardized incidence ratio was calculated for all cancer sites in the overall cohort by comparison with national incidence rates for economically active men at the 1960 census. The standardized incidence ratios for cancers of the breast, pleura (mesothelioma), larynx, and bladder and for soft tissue sarcoma were elevated, while those for non-Hodgkins and Hodgkins lymphoma were lower. The standardized incidence ratio for leukemia for electrical workers with 10 or more economically active years was 1.41. The standardized incidence ratio for brain tumors in this subgroup of electrical workers was 1.14. These results from a large, national, population-based study at the Cancer Registry of Norway give support to previous findings of a possible association between electrical work and the risk of leukemia.

Adult↗
PubMed2003

Health risks of electromagnetic fields. Part II: Evaluation and assessment of radio frequency radiation.

The increasing use of different radio frequency (RF)-emitting devices in residential and occupational settings has raised concerns about possible health effects of RF energy emitted by such devices. The debate about the potential risks associated with RF fields will persist with the prevalent network-connected wireless products and services targeting the marketplace for all kinds of consumer use. The aim of this article is to provide biomedical researchers with a review and critical evaluation of the current literature on acute and long-term health risks associated with RF radiation (RFR). Issues examined include safety standards for RFR; dosimetry and measurement surveys; and toxicological, epidemiological, and clinical studies of health outcomes that may be associated with RFR. Overall, the existing evidence for a causal relationship between RFR and adverse health effects is limited. Additional research is needed to clarify possible associations between RFR and biological effects noted in some studies. Particular attention should be directed toward long-term, low-level exposure to RFR.

Animals↗