Low Frequency Electromagnetic Field Exposure Research Articles

No effects of power line frequency extremely low frequency electromagnetic field exposure on selected neurobehavior tests of workers inspecting transformers and distribution line stations versus controls

We aimed to evaluate the interference of 50 Hz extremely low frequency electromagnetic field (ELF-EMF) occupational exposure on the neurobehavior tests of workers performing tour-inspection close to transformers and distribution power lines. Occupational short-term "spot" measurements were carried out. 310 inspection workers and 300 logistics staff were selected as exposure and control. The neurobehavior tests were performed through computer-based neurobehavior evaluation system, including mental arithmetic, curve coincide, simple visual reaction time, visual retention, auditory digit span and pursuit aiming. In 500 kV areas electric field intensity at 71.98% of total measured 590 spots were above 5 kV/m (national occupational standard), while in 220 kV areas electric field intensity at 15.69% of total 701 spots were above 5 kV/m. Magnetic field flux density at all the spots was below 1,000 μT (ICNIRP occupational standard). The neurobehavior score changes showed no statistical significance. Results of neurobehavior tests among different age, seniority groups showed no significant changes. Neurobehavior changes caused by daily repeated ELF-EMF exposure were not observed in the current study.

Gene expression and reproductive abilities of male Drosophila melanogaster subjected to ELF–EMF exposure

Extremely low frequency electromagnetic field (ELF–EMF) exposure is attracting increased attention as a possible disease-inducing factor. The in vivo effects of short-term and long-term ELF–EMF exposure on male Drosophila melanogaster were studied using transcriptomic analysis for preliminary screening and QRT-PCR for further verification.Transcriptomic analysis indicated that 439 genes were up-regulated and 874 genes were down-regulated following short-term exposures and that 514 genes were up-regulated and 1206 genes were down-regulated following long-term exposures (expression >2- or <0.5-fold, respectively). In addition, there are 238 up-regulated genes and 598 down-regulated genes in the intersection of short-term and long-term exposure (expression >2- or <0.5-fold). The DEGs (differentially expressed genes) in D. melanogaster following short-term exposures were involved in metabolic processes, cytoskeletal organization, mitotic spindle organization, cell death, protein modification and proteolysis. Long-term exposure let to changes in expression of genes involved in metabolic processes, response to stress, mitotic spindle organization, aging, cell death and cellular respiration. In the intersection of short-term and long-term exposure, a series of DEGs were related to apoptosis, aging, immunological stress and reproduction.To check the ELF–EMF effects on reproduction, some experiments on male reproduction ability were performed. Their results indicated that short-term ELF–EMF exposure may decrease the reproductive ability of males, but long-term exposures had no effect on reproductive ability. Down-regulation of ark gene in the exposed males suggests that the decrease in reproductive capacity may be induced by the effects of ELF–EMF exposure on spermatogenesis through the caspase pathway. QRT-PCR analysis confirmed that jra, ark and decay genes were down regulated in males exposed for 1 Generation (1G) and 72h, which suggests that apoptosis may be inhibited in vivo. ELF–EMF exposure may have accelerated cell senescence, as suggested by the down-regulation of both cat and jra genes and the up-regulation of hsp22 gene. Up-regulation of totA and hsp22 genes during exposure suggests that exposed flies might induce an in vivo immune response to counter the adverse effects encountered during ELF–EMF exposure. Down-regulation of cat genes suggests that the partial oxidative protection system might be restrained, especially during short-term exposures. This study demonstrates the bioeffects of ELF–EMF exposure and provides evidence for understanding the in vivo mechanisms of ELF–EMF exposure on male D. melanogaster.

RF and ELF electromagnetic field exposure of children in the french ELFE birth cohort

Background : Knowledge on Radiofrequency (RF) and Extremely Low Frequency (ELF) electromagnetic fields (EMF) exposure of children remains scarce, despite their growing use and their potential health effects. There is a need for studies taking into account every source of children exposure, including emerging ones, with longitudinal design to capture changes while growing, from in-utero to the adolescence. Aims: to characterize and follow RF and ELF exposure in children of the French ELFE birth cohort. Methods: 18918 children born in 2011 have been included. RF and ELF exposure will be assessed by questionnaires. Jobs and company activity will be coded with international classifications, and a job-exposure matrix will be applied to assess maternal occupational exposure during pregnancy. Domestic uses (Wi-Fi, cordless phone, mobile phone, electrical appliances, transportation means…) will be collected on questionnaires. Residential exposure will be assessed by using geocoded residential addresses and mapping of EMF sources. An exposure study will be performed in a subgroup of 400 children (when 3 yrs old). Housing and household characteristics and a time-activity diary will be completed, and numerous RF bands and ELF 50Hz will be measured at different places in each room and during 24 h in the living room. Results : questionnaires at birth, 2 months and 1 year of life have been already administered, and follow-up at 2 years is scheduled in 2013. Perspectives: Interactions between EMF and other radiations or chemical exposures will be studied, in relation with health outcomes collected at each follow-up. Other factors influencing children’s health and development (social, psychological, medical and familial factors), also collected will allow an accurate assessment of the etiology of health events. Future collaboration with other international birth cohorts to better understand the etiology of rare diseases such as pediatric cancers will be considered.

Exposure to extremely low frequency electromagnetic fields during pregnancy and the risk of spontaneous abortion: a case-control study.

Exposure to extremely low frequency electromagnetic fields is increasingly common, but the potential influence on pregnant women has not been thoroughly investigated. In this case-control study, 58 women who had an unexplained spontaneous abortion at < 14 weeks gestation and 58 matched pregnant women >14 weeks gestation were enrolled in 2012. The women completed the questionnaire, which was used to collect data about socioeconomic and obstetric characteristics, medical and reproductive histories. Then, to evaluate the extremely low frequency electromagnetic fields , we determined the magnitude of electromagnetic fields in the participants' houses by an exposure level tester (3D EMF tester/ Model: ELF-828; Taiwan).The instrument covers a limited frequency range (30 HZ to 3 KHZ). The magnitude of extremely low frequency electromagnetic fields in the participants' houses was significantly different between the two groups (P<0.001). Extremely low frequency electromagnetic fields exposure is probably related to early spontaneous abortions.

The preventive effect of lotus seedpod procyanidins on cognitive impairment and oxidative damage induced by extremely low frequency electromagnetic field exposure

The present study investigated the effects of lotus seedpod procyanidins (LSPCs) administered by oral gavage on the cognitive deficits and oxidative damage of mice at extremely low frequency electromagnetic field (ELF-EMF) exposure (50 Hz, 8 mT, 28 days). The results showed that 90 mg kg⁻¹ LSPCs treatment significantly increased body weight compared with the ELF-EMF group at ELF-EMF exposure and effectively maintained liver index, thymus index, kidney index and spleen index close to normal. A water maze test indicated that learning and memory abilities of the ELF-EMF group deteriorated significantly with ELF-EMF exposure when compared with the control group, but the ELF-EMF + LSPCs90 group had remarkably improved learning and memory abilities compared with the ELF-EMF group. Malondialdehyde (MDA), reactive oxygen species (ROS), nitric oxide (NO) and nitric oxide synthase (NOS) mostly exhibited significant increases, while the activities of glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) decreased significantly under ELF-EMF exposure in the ELF-EMF group. LSPCs (especially 60, 90 mg kg⁻¹) administration decreased MDA, ROS, NO content and lowered NOS activity in LSPCs treatment groups. Furthermore, LSPCs (60, 90 mg kg⁻¹) treatment significantly augmented GPx, CAT, SOD activity in the hippocampus and serum. Pathological observation showed that number of pyramidal cells of the CA1 and CA3 regions of the hippocampus of the LSPCs treatment groups was significantly greater than the ELF-EMF group. All the data suggested that the LSPCs can effectively prevent learning and memory damage and oxidative damage caused by the ELF-EMF, most likely through the ability of LSPCs to scavenge oxygen free radicals and to stimulate antioxidant enzyme activity.

Effect of extremely low frequency electromagnetic field exposure on sleep quality in high voltage substations

This study aims to investigate the effect of extremely low frequency electromagnetic fields exposure on sleep quality in high voltage substations (132, 230 and 400 KV) in Kerman city and the suburbs. For this purpose, the electric field intensity and magnetic flux density were measured in different parts of substations, and then the occupational exposure was estimated by averaging electric field intensity and magnetic flux density in a shift work. The cases comprised 67 workers who had been exposed to electromagnetic fields in age range of 24–57 and the controls were 110 persons the age ranged 24–50 years. Sleep quality of both groups was evaluated by the Pittsburgh Sleep Quality Index questionnaire (PSQI). Finally, these data were subjected to statistical analysis. The results indicated that 90.5% of cases and 85.3% of controls had the poor quality sleep according to PSQI (P-value=0.615). Total sleep quality score mean for the case and control groups were 10.22 ± 3.4 and 9.74 ± 3.62 (P-value=0.415) ,respectively. Meantime to fall asleep for cases(35.68 ± 26.25 min) was significantly higher than for controls (28.89 ± 20.18 min) (P-value=0.002). Cases had average sleep duration of 5.49 ± 1.31 hours, which was lower ascompared with control subjects (5.90 ± 1.67hours). Although there was a higher percentage for the case group with poor sleep quality than the control group, but no statistically significant difference was observed.

Effect of Acute Extremely Low Frequency Electromagnetic Field Exposure on the Antioxidant Status and Lipid Levels in Rat Brain

It is generally accepted that electromagnetic fields (EMF) can exert biological effects; however, the mechanisms by which EMF elicits responses are still unknown. The present study was designed to assess the immediate effects of acute EMF exposure, movement restriction, and the combination of both on the antioxidant systems and lipid content in the whole brain of rat. Thirty two male Wistar rats were arranged in four groups: control, EMF exposed, movement restrained (MR), and EMF + MR for 2 h. Rats were then sacrificed and their brains analyzed for superoxide dismutase and catalase activities, reduced glutathione, nitric oxide, total cholesterol, and triacylglycerol levels, as well as plasma corticosterone concentrations. Acute exposure to EMF induces reduction in catalase and superoxide dismutase activities, whereas the combination of EMF + MR also decreases both reduced glutathione and nitric oxide levels. Our results show that the acute exposure to EMF does not induce elevation of stress-hormone corticosterone but impairs the antioxidant status in rat brain. Plasma corticosterone concentration and antioxidant data indicate that the acute exposure to EMF appears to be a mild stressor that leads to some adaptive responses due to the activation of systems controlling the brain oxidative balance.

Measurement and Analysis of Extremely Low Frequency Electromagnetic Field Exposure in Oman

Concern about the possible health effects from exposure to extremely low frequency (ELF) electromagnetic fields is increasing worldwide. This paper presents analyses of measurements of low frequency magnetic and electric fields caused by conductors carrying current in the Oman electric power system. Measurements were taken during the summer period at around 3 PM to capture peak loads. Field measurements were from several high voltage environments which including different types of electricity infrastructure including overhead lines, underground cables and substations. The measured values were compared to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) standards for both general public and occupational exposure. All the Oman values of electric and magnetic fields are lower than the recommended values provided by ICNIRP.

Effects of Power Frequency Magnetic Fields Acute Exposure on Growth and Apoptosis of PC12 Cells

PC12 cells were cultured in vitro,then exposed to 50 Hz and 100 μT extremely low frequency electromagnetic fields for 24 h.The proliferation activity,cell cycle and apoptosis was detected respectively by methyl thiazolyl tetrazolium colorimetry,flow cytometry and acridine orange/ethidium bromide,double label immunofluorescence.It was found that: 1) After exposure,proliferation activity was decreased at 0 h(P0.01),but increased at 8 h(P0.05) and 12 h(P0.01),and there were no significant changes at 4 h.2) After exposure,G0/G1 cells were increased(P0.01) and S cells were decreased(P0.05) at 0 h,G2/M cells were increased(P0.05) at 6 h,G0/G1 cells were decreased(P0.01) and S cells were increased(P0.05) at 12 h,there were no significant changes at 24 h.3) The apoptotic rates were increased significantly at 12 h(P0.05),18 h(P0.01) and 24 h(P0.01) during exposure,and 6 h,12 h,18 h and 24 h after exposure(P0.01).The results indicated that 50 Hz and 100 μT extremely low frequency electromagnetic fields exposure for 24 h can change the proliferation activity and cell cycle of PC12 cells and increase cell apoptosis.

Signal processing and wavelet analysis of simultaneously registered blood pressure and laser Doppler flow signals during extremely low frequency electromagnetic field exposure in humans in vivo

Regulation of microcirculation and other physiological processes have strong non-linear character and involves complex of different processes, every process with own hierarchy in time and different frequencies. Traditional Fourier analysis does not provide sufficient power and resolution to elucidate characteristic of low vasomotor frequencies. Therefore, we apply a Time–frequency (wavelet) analysis on the signal obtained by Laser Doppler flow meter (LDF) at 25 healthy volunteers, exposed at the same time to low frequency electromagnetic fields, used for physiotherapy. Signal processing include Matlab based algorithms for digital signal processing (DSP) and Matlab Spectral analysis toolbox of simultaneous registered variations in Blood Pressure (BP), Laser Doppler Flow (LDF), and Intravital microscopy (IVM). It provides useful information about regulatory mechanisms and vegetative nervous system regulation of peripheral blood flow. Continuous changes in blood pressure variations and perfusion of extremities were measured prior and after 10, 20, and 30 min ELF-EMF (10, 16, 20, and 30 mT), exposure. After wavelet analysis of the blood flow signals and vasomotion changes signals, several frequency bands were distinguished: 0.0095–0.02 Hz; (α), 0.02–0.06 Hz; (β), 0.06–0.15 Hz; (γ), 0.15–0.4 Hz; (δ), and 0.4–1 Hz; (θ) for LDF data and 0.0095–0.4 Hz; (α), 0.4–0.75 Hz; (β), 0.75–0.9 Hz; (γ), 0.9–1.2 Hz; (δ), and 1.2–2 Hz; (θ) for IVM data. In this study, overlapping of some frequency bands between IVM and LDF data were found. Overlapping of the frequency bands has two ways of interpretation, one related with similarity of the structures and tissues and other related with output of ELF-EMF stimulation. We used also correlation and cross-correlation analysis to compare non-invasive (BP measurements and LDF) data, with invasive intravital microscopy (IVM) data (obtained on animals in vivo), during ELF-EMF stimulation. IVM data were used as a reference value, for certain information of possible mechanisms of biological response at the tissue and blood vessel level after ELF-EMF exposure with frequency in the range from 10 to 50 Hz and magnetic flux density of 20 mT. Comparative analysis of IVM and LDF, frequency bands show that they have statistical significant changes after ELF-EMF stimulation. Five subintervals were confirmed (α-, β-, γ-, δ-, and θ). The findings indicate that local ELF-EMF exposure at the constant temperature of the media increases skin blood flow at the upper extremities which have a contribution to the α-frequency band at IVM.

Extremely low frequency electromagnetic field exposure does not modulate toll-like receptor signaling in human peripheral blood mononuclear cells

The effects of extremely low frequency electromagnetic fields (ELF-EMF) on human health remain unclear. It has been reported that ELF-EMF may modulate the innate immune response to microorganisms in animal models and mammalian cell-lines. With the recently gained insight in innate immune signaling and the discovery of pattern recognition, we aim to study whether ELF-EMF modulates innate inflammatory signaling pathways. We used human peripheral blood mononuclear cells (PBMCs), isolated from blood from healthy volunteers, which we stimulated with specific TLR2 and TLR4 ligands, and with several microorganisms. The cells were subsequently exposed in Bdc=3μT to a highly controlled and standardized ELF-EMF signal (20–5000Hz, Bac=5μT, 30min) and cytokine production was measured at different time points after stimulation. No significant difference in immune response, as reflected by IL-1β, IL-6, TNFα, IL-8 and IL-10 production, could be detected after stimulation with LPS (TLR4 ligand), Pam3Cys (TLR2 ligand) or a panel of heat killed microorganisms: Mycobacterium tuberculosis, Salmonella typhimurium, Candida albicans, Aspergillus fumigatus and Staphylococcus aureus (multiple TLR ligands). We therefore conclude that under our experimental conditions, ELF-EMF does not modulate the innate immune response of human primary cells after TLR stimulation in vitro.

Extremely low frequency electromagnetic field exposure affects fertilization outcome in swine animal model

Modern society continuously exposes the population to electromagnetic radiation, the effects of which on human health, in particular reproduction, are still unknown. The aim of this research was to assess the effect of acute (1h) exposure of boar spermatozoa to a 50Hz extremely low frequency electromagnetic field (ELF-EMF) on early fertility outcome. The effect of intensities ranging from 0 to 2mT on morpho-functional integrity of capacitated spermatozoa was examined in vitro. The oviducts containing or without spermatozoa were then exposed to the minimum in vivo, TD50, and maximum intensities determined in vitro, 4h before ovulation. The effects of ELF-EMF on spermatozoa in terms of early embryo development were evaluated after 12h and 6 days. It was found that in vitro ELF-EMF >0.5mT induced a progressive acrosome damage, thus compromising the ability of spermatozoa to undergo acrosomal reaction after zona pellucida stimulation and reducing the in vitro fertilization outcome. These effects became evident at 0.75mT and reached the plateau at 1mT. Under in vivo conditions, the ELF-EMF intensity of 1mT was able to compromise sperm function, significantly reducing the fertilization rate. In addition, the exposure of oviducts to fields ≥ 0.75mT in the absence of spermatozoa was able to negatively affect early embryo development. In fact, it was found to cause a slowdown in the embryo cleavage. In conclusion, it was demonstrated how and at which intensities ELF-EMF negatively affect early fertility outcome in a highly predictive animal model.

Increased protein synthesis by cells exposed to a 1,800-MHz radio-frequency mobile phone electromagnetic field, detected by proteome profiling

PurposeTo investigate whether or not low intensity radio frequency electromagnetic field exposure (RF-EME) associated with mobile phone use can affect human cells, we used a sensitive proteome analysis method to study changes in protein synthesis in cultured human cells.MethodsFour different cell kinds were exposed to 2 W/kg specific absorption rate in medium containing 35S-methionine/cysteine, and autoradiography of 2D gel spots was used to measure the increased synthesis of individual proteins.ResultsWhile short-term RF-EME did not significantly alter the proteome, an 8-h exposure caused a significant increase in protein synthesis in Jurkat T-cells and human fibroblasts, and to a lesser extent in activated primary human mononuclear cells. Quiescent (metabolically inactive) mononuclear cells, did not detectably respond to RF-EME. Since RF exposure induced a temperature increase of less than 0.15°C, we suggest that the observed cellular response is a so called “athermal” effect of RF-EME.ConclusionOur finding of an association between metabolic activity and the observed cellular reaction to low intensity RF-EME may reconcile conflicting results of previous studies. We further postulate that the observed increased protein synthesis reflects an increased rate of protein turnover stemming from protein folding problems caused by the interference of radio-frequency electromagnetic fields with hydrogen bonds. Our observations do not directly imply a health risk. However, vis-a-vis a synopsis of reports on cells stress and DNA breaks, after short and longer exposure, on active and inactive cells, our findings may contribute to the re-evaluation of previous reports.Electronic supplementary materialThe online version of this article (doi:10.1007/s00420-010-0513-7) contains supplementary material, which is available to authorized users.

Extremely low-frequency electromagnetic fields exposure and female breast cancer risk: a meta-analysis based on 24,338 cases and 60,628 controls

Exposure to extremely low-frequency electromagnetic fields (ELF-EMF) has been suggested to increase female breast cancer risk; however, the data have been inconclusive. In order to derive a more precise estimation of the relationship, a meta-analysis was performed. Medline, PubMed, Embase, the Cochrane Library and Web of Science were searched. Crude ORs with 95% CIs were used to assess the strength of association between ELF-EMF exposure and female breast cancer risk. A total of 15 studies published over the period 2000 to 2009 including 24,338 cases and 60,628 controls were involved in this meta-analysis. The results showed no significant association between ELF-EMF exposure and female breast cancer risk in total analysis (OR = 0.988, 95% CI = 0.898-1.088) and in all the subgroup analyses by exposure modes, menopausal status, and estrogen receptor status. This result is in accordance with the previous meta-analysis carried out by Erren in 2000. In conclusion, this meta-analysis suggests that ELF-EMF exposure has no association with the susceptibility of female breast cancer.

Effects of Acute and Chronic Low Frequency Electromagnetic Field Exposure on PC12 Cells during Neuronal Differentiation

Background/Aims. The purpose of this study was to provide information about the in vitro neuritogenesis during cell exposure to extremely low frequency electromagnetic fields (ELF-EMFs) of different intensities and durations using pheochromocytoma-derived cell line (PC12 cells) as neuronal model. Methods. Proliferative rates and neuritogenesis were tested by colorimetric assay and morphological analysis, respectively; reactive oxygen species (ROS) levels and intracellular Ca²⁺ variations monitored using single cell videomicroscopy. Results. The long-lasting ELF-EMF exposure (0.1-1.0 mT) did not appear to significantly affect the biological response (proliferation and neuritogenesis). However, during the acute ELF-EMF exposure (30 min), in undifferentiated PC12 cells, there were increased ROS levels and decreased catalase activity, that, conversely, resulted increased after chronic exposure (7 days) at 1.0 mT. Acute exposure (0.1-1.0 mT) affected the spontaneous intracellular Ca²⁺ variations in undifferentiated cells, in which basal intracellular Ca²⁺ resulted increased after chronic exposure. In addition acute exposure affected cell response to a depolarizing agent, while basal membrane potential was not changed. Conclusion. Even if further studies remain necessary to identify the ROS/intracellular Ca²⁺cross-talking pathway activated by ELF-EMF exposure, we support the hypothesis that ROS and Ca²⁺ could be the cellular “primum movens” of the ELF-EMF induced effects on biological systems.

DNA fragmentation in human fibroblasts under extremely low frequency electromagnetic field exposure

Extremely low frequency electromagnetic fields (ELF-EMFs) were reported to affect DNA integrity in human cells with evidence based on the Comet assay. These findings were heavily debated for two main reasons; the lack of reproducibility, and the absence of a plausible scientific rationale for how EMFs could damage DNA. Starting out from a replication of the relevant experiments, we performed this study to clarify the existence and explore origin and nature of ELF-EMF induced DNA effects. Our data confirm that intermittent (but not continuous) exposure of human primary fibroblasts to a 50 Hz EMF at a flux density of 1 mT induces a slight but significant increase of DNA fragmentation in the Comet assay, and we provide first evidence for this to be caused by the magnetic rather than the electric field. Moreover, we show that EMF-induced responses in the Comet assay are dependent on cell proliferation, suggesting that processes of DNA replication rather than the DNA itself may be affected. Consistently, the Comet effects correlated with a reduction of actively replicating cells and a concomitant increase of apoptotic cells in exposed cultures, whereas a combined Fpg-Comet test failed to produce evidence for a notable contribution of oxidative DNA base damage. Hence, ELF-EMF induced effects in the Comet assay are reproducible under specific conditions and can be explained by minor disturbances in S-phase processes and occasional triggering of apoptosis rather than by the generation of DNA damage.

Low-frequency pulsed electromagnetic field exposure can alter neuroprocessing in humans

Extremely low-frequency magnetic fields (from DC to 300 Hz) have been shown to affect pain sensitivity in snails, rodents and humans. Here, a functional magnetic resonance imaging study demonstrates how the neuromodulation effect of these magnetic fields influences the processing of acute thermal pain in normal volunteers. Significant interactions were found between pre- and post-exposure activation between the sham and exposed groups for the ipsilateral (right) insula, anterior cingulate and bilateral hippocampus/caudate areas. These results show, for the first time, that the neuromodulation induced by exposure to low-intensity low-frequency magnetic fields can be observed in humans using functional brain imaging and that the detection mechanism for these effects may be different from those used by animals for orientation and navigation. Magnetoreception may be more common than presently thought.

Effects of prolonged iron overload and low frequency electromagnetic exposure on spatial learning and memory in the young rat

Low-frequency electromagnetic fields (EMF) have been suggested to affect the brain via alterations of blood–brain barrier permeability to iron. Because of an immature blood–brain barrier, the young brain may be particularly vulnerable to EMF exposure. It is therefore possible that behavioral and neurotoxic effects resulting from EMF-induced iron excess in the brain would be greater in young adults. The objective of the present study was to investigate the interaction between low-frequency EMF and iron overload in young rats. In Experiment 1, we tested the effects of iron overload on spatial learning and memory. Iron treatment did not affect performance in a reference (Morris water maze) and a working memory task (8-arm radial maze). In contrast, detection of a spatial change in an object exploration task was impaired. These effects correlated with modifications of the serotoninergic metabolism. In Experiment 2, the combination of EMF exposure and iron overload was tested. As in Experiment 1, rats were not impaired in reference and working memory tasks but were mildly impaired in the detection of the spatial change. Overall, the results showed an effect of iron overload on spontaneous spatial memory processes. However, low-frequency EMF exposure did not potentiate the effects of iron overload in young rats.

Extremely low-frequency electromagnetic field exposure during chronic morphine treatment strengthens downregulation of dopamine D2 receptors in rat dorsal hippocampus after morphine withdrawal

The aim of this study was to investigate the effect of extremely low-frequency electromagnetic field (ELF-EMF) exposure during morphine treatment on dopamine D2 receptor (D2R) density in the rat dorsal hippocampus following withdrawal. Rats were exposed to ELF-EMF (20 Hz, 14 mT) or sham exposed for 1h per day before injection of morphine (10mg/kg, i.p.) once daily for 12 days. The saline control group was sham exposed for the same period. Immunohistochemistry was used to detect the density of D2Rs on the 1st, 3rd and 5th morphine withdrawal days. The results showed that the density of D2Rs in sham-exposed morphine-treated rats on the 1st and 3rd days of morphine withdrawal was significantly lower than that of the saline control group. The ELF-EMF-exposed morphine group also exhibited a significantly lower density of D2Rs on the 1st and 3rd withdrawal days relative to the sham-exposed morphine group. However, the D2R density in both groups tended to recover as morphine withdrawal days increased. The results suggest that dorsal hippocampal D2Rs are sensitive to morphine withdrawal and that this is potentiated by ELF-EMF pre-exposure during morphine treatment.

Compute extremely low-frequency electromagnetic field exposure by 3-D impendance method

A 3-D impedance method has been introduced to compute the electric currents induced in a human body exposed to extremely low-frequency electromagnetic field. The 3-D impedance method has been deduced from Maxwell equations and is put into the computation and simulation effectively to the visible human body model, which has 196×114×626 cells and more than 40 types of tissues. As the result, two representative cases are investigated. One is exposure of the human body to 100 μT (1 000 mG), the limit recommended by the International Commission on Non-Ionizing Radiation Protection for the public and the other one is the exposure of human body to 0.4 μT (4 mG), the level at which a statistical link appears with a doubled risk of development of childhood leukaemia. The distribution of induced current density can be obtained and the maximum of induced current are found to be 16 mA/m 2 and 0.07 mA/m 2.