ELF Noise Fields: A Review

The debate as to whether low-level electromagnetic fields can affect biological systems and in the long term cause health effects has been going on for a long time. Yet the interaction of weak electromagnetic fields (EMF) with living cells, undoubtedly a most important phenomenon, is still not well understood. The exact mechanisms by which the effects are produced have not been identified. Furthermore, it is not possible to clearly define which aspects of an EMF exposure that constitute the “dose.” One of the groups that contributed to solving this problem is the Bioelectromagnetics group at Catholic University of America (CUA), Washington, D.C. Their work has been devoted to investigating the physical parameters that are needed to obtain an effect of EMF exposure on biological systems, and also how to inhibit the effect. This is a review of their work on bioeffects caused by low-level EMF, their dependence on coherence time, constancy, spatial averaging, and also how the effects can be modified by an applied ELF noise magnetic field. The group has been using early chick embryos, and L929 and Daudi cells as their main experimental systems. The review also covers the work of other groups on low-level effects and the inhibition of the effects with an applied noise field. The group at CUA has shown that biological effects can be found after exposure to low-level ELF and RF electromagnetic fields, and when effects are observed, applying an ELF magnetic noise field inhibits the effects. Also, other research groups have tried to replicate the studies from the CUA group, or to apply EMF noise to suppress EMF-induced effects. Replications of the CUA effects have not always been successful. However, in all cases where the noise field has been applied to prevent an observed effect, it has been successful in eliminating the effect.     

Bidirectional frequency-dependent effect of extremely low-frequency electromagnetic field on E. coli K-12

In the present work, the frequency-dependent effects of extremely low-frequency electromagnetic field (ELF EMF) on Escherichia coli K-12 growth have been studied. The frequency-dependent effects of ELF EMF have shown that it can either stimulate or inhibit the growth of microbes. However, the mechanism by which the ELF EMF affects the bacterial cells is not clear yet. It was suggested that the aqua medium can serve as a target through which the biological effect of ELF EMF on microbes may be realized. To check this hypothesis, the frequency-dependent effects (2, 4, 6, 8, 10 Hz, B = 0.4 mT, 30 min) of ELF EMF on the bacterial growth were studied in both cases where the microbes were in the culture media during the exposure and where culture media was preliminarily exposed to the ELF EMF before the addition of bacteria. For investigating the cell proliferation, the radioactive [³H]-thymidine assay was carried out. It has been shown that EMF at 4 Hz exposure has pronounced stimulation while at 8 Hz it has inhibited cell proliferation.     

Microwave electromagnetic field regulates gene expression in T-lymphoblastoid leukemia CCRF-CEM cell line exposed to 900 MHz

Electric, magnetic, and electromagnetic fields are ubiquitous in our society, and concerns have been expressed regarding possible adverse effects of these exposures. Research on Extremely Low-Frequency (ELF) magnetic fields has been performed for more than two decades, and the methodology and quality of studies have improved over time. Studies have consistently shown increased risk for childhood leukemia associated with ELF magnetic fields. There are still inadequate data for other outcomes. More recently, focus has shifted toward Radio Frequencies (RF) exposures from mobile telephony. There are no persuasive data suggesting a health risk, but this research field is still immature with regard to the quantity and quality of available data. This technology is constantly changing and there is a need for continued research on this issue. To investigate whether exposure to high-frequency electromagnetic fields (EMF) could induce adverse health effects, we cultured acute T-lymphoblastoid leukemia cells (CCRF-CEM) in the presence of 900?MHz MW-EMF generated by a transverse electromagnetic (TEM) cell at short and long exposure times. We evaluated the effect of high-frequency EMF on gene expression and we identified functional pathways influenced by 900?MHz MW-EMF exposure.     

Extremely low‐frequency electromagnetic fields accelerates wound healing modulating MMP‐9 and inflammatory cytokines

Objectives

In our previous reports, we have demonstrated that extremely low‐frequency electromagnetic fields (ELF‐EMF) exposure enhances the proliferation of keratinocyte. The present study aimed to clarify effects of ELF‐EMF on wound healing and molecular mechanisms involved, using a scratch in vitro model.

Materials and methods

The wounded monolayer cultures of human immortalized keratinocytes (HaCaT), at different ELF‐EMF and Sham exposure times were monitored under an inverted microscope. The production and expression of IL‐1β, TNF‐α, IL‐18 and IL‐18BP were measured by enzyme‐linked immunosorbent assay and quantitative real‐time PCR. The activity and the expression of matrix metalloproteinases (MMP)‐2/9 was evaluated by zymography and Western blot analysis, respectively. Signal transduction proteins expression (Akt and ERK) was measured by Western blot.

Results

The results of wound healing in vitro assay revealed a significant reduction of cell‐free area time‐dependent in ELF‐EMF‐exposed cells compared to Sham condition. Gene expression and release of cytokines analysed were significantly increased in ELF‐EMF‐exposed cells. Our results further showed that ELF‐EMF exposure induced the activity and expressions of MMP‐9. Molecular data showed that effects of ELF‐EMF might be mediated via Akt and ERK signal pathway, as demonstrated using their specific inhibitors.

Conclusions

Our results highlight ability of ELF‐EMF to modulate inflammation mediators and keratinocyte proliferation/migration, playing an important role in wound repair. The ELF‐EMF accelerates wound healing modulating expression of the MMP‐9 via Akt/ERK pathway.

     

Electromagnetic effects – From cell biology to medicine

In this review we compile and discuss the published plethora of cell biological effects which are ascribed to electric fields (EF), magnetic fields (MF) and electromagnetic fields (EMF). In recent years, a change in paradigm took place concerning the endogenously produced static EF of cells and tissues. Here, modern molecular biology could link the action of ion transporters and ion channels to the “electric” action of cells and tissues. Also, sensing of these mainly EF could be demonstrated in studies of cell migration and wound healing. The triggers exerted by ion concentrations and concomitant electric field gradients have been traced along signaling cascades till gene expression changes in the nucleus.Far more enigmatic is the way of action of static MF which come in most cases from outside (e.g. earth magnetic field).All systems in an organism from the molecular to the organ level are more or less in motion. Thus, in living tissue we mostly find alternating fields as well as combination of EF and MF normally in the range of extremely low-frequency EMF. Because a bewildering array of model systems and clinical devices exits in the EMF field we concentrate on cell biological findings and look for basic principles in the EF, MF and EMF action.As an outlook for future research topics, this review tries to link areas of EF, MF and EMF research to thermodynamics and quantum physics, approaches that will produce novel insights into cell biology.     

Effects of global system for mobile communications 1800 MHz radiofrequency electromagnetic fields on gene and protein expression in MCF-7 cells

Despite many studies over a decade, it still remains ambiguous as to the real biological effects induced by radiofrequency electromagnetic fields (RF EMF) utilized in mobile telephony. Here we investigated global gene and protein responses to RF EMF simulating the Global System for Mobile Communications (GSM) 1800 MHz signal in human breast cancer cell line MCF-7 using genomic and proteomic approaches. GeneChip analysis identified a handful of consistent changed genes after exposure to RF EMF at specific absorption rates (SAR) of up to 3.5 W/kg for 24 h. However, these differentially transcribed genes could not be further confirmed by real-time RT-PCR assay. Meanwhile, systematic proteome analysis of the MCF-7 cells revealed that a few but different proteins were differentially expressed under continuous or intermittent RF EMF exposure at SAR of 3.5 W/kg for 24 h or less, implying that the observed effects might have occurred by chance. Overall, the present study does not provide convincing evidence that RF EMF exposure under current experimental conditions can produce distinct effects on gene and protein expression in the MCF-7 cells.     

The influence of a low- and high-frequency electromagnetic fields on seeds

It was shown that the exposure of seeds in the rest phase to a low-frequency pulse electromagnetic field leads to substantial changes in seed physiology during germination. The changes at the physiological level in sprouting seeds depend not only on the frequency of the external EMF and its power characteristics but also on the kind of seeds. Low- and high-frequency electromagnetic fields are able to produce a biostimulation effect; however, the mechanisms of its appearance are different in their nature. The biochemical studies of seeds after EMF treatment in the modes resulting in expressed biological effects showed an increase in the activity of alpha-amylase, which testifies an increase in the gibberellin output and in the activity of the hydrolytic enzyme sour phosphatase. The response of seeds to EMF treatment demonstrates the possibility of electromagnetic control of growth processes.     

Electromagnetic fields and epidemiology: An overview inspired by the fourth course at the International School of Bioelectromagnetics

The fourth course at the International School of Bioelectromagnetics addressed various aspects of the epidemiology of exposure to electromagnetic fields (EMF). In this overview, inspired by the lectures and the discussions among participants, we summarize current knowledge on exposure to EMF and disease risk, with emphasis on studies of use of mobile phones and brain tumours and exposure to power lines and childhood leukaemia. Sources of bias and error hamper straightforward conclusions in some areas and, in order to move forward, improvements in study design and exposure assessment are necessary. The scientific evidence available to date on possible long‐term effects from exposure to ELF and RF fields is not strong enough to revise current protection limits based on the known acute effects of such exposures. Precautionary measures may be considered to reduce ELF exposure of children or exposure to RF during mobile phone use, keeping in mind that it is unclear whether they involve any preventive benefit. Possible health effects from mobile phone use in adults and in children should be investigated further by prospective epidemiological studies with improved exposure assessment and brain tumour incidence rates should be monitored. Further studies on the relation between childhood leukaemia and ELF magnetic fields would be worthwhile if they focus on heavily exposed groups and attempt to minimize possible selection bias. In conclusion, epidemiological studies conducted with appropriate diligence can play a key role in finding the answers. Bioelectromagnetics 30:511–524, 2009. © 2009 Wiley‐Liss, Inc.     

Exposure to ELF magnetic and ELF-modulated radiofrequency fields: the time course of physiological and cognitive effects observed in recent studies (2001-2005)

In 2002, we published a review of the cognitive and physiological effects of extremely low frequency magnetic fields (ELF MFs) and ELF-modulated radiofrequency fields associated with mobile phones. Since the original preparation of that review, a significant number of studies have been published using techniques such as electroencephalography, event-related potentials and positron emission tomography to investigate electromagnetic field effects upon human physiology and various measures of performance (cognitive, perceptual, behavioral). We review these recent studies, and when effects were observed, we reference the time course of observed effects (immediate or delayed). In our concluding remarks, we discuss a number of variables that are not often considered in human bioelectromagnetics studies, such as personality, individual differences and the specific laterality of ELF MF and mobile phone exposure over the brain. We also consider the sensitivity of various physiological assays and performance measures in the study of biological effects of electromagnetic fields.     

Extremely low frequency electromagnetic fields as effectors of cellular responses in vitro: possible immune cell activation

There is presently an intense discussion if electromagnetic field (EMF) exposure has consequences for human health. This include exposure to structures and appliances that emit in the extremely low frequency (ELF) range of the electromagnetic spectrum, as well as emission coming from communication devices using the radiofrequency part of the spectrum. Biological effects of such exposures have been noted frequently, although the implication for specific health effects is not that clear. The basic interaction mechanism(s) between such fields and living matter is unknown. Numerous hypotheses have been suggested, although none is convincingly supported by experimental data. Various cellular components, processes, and systems can be affected by EMF exposure. Since it is unlikely that EMF can induce DNA damage directly, most studies have examined EMF effects on the cell membrane level, general and specific gene expression, and signal transduction pathways. In addition, a large number of studies have been performed regarding cell proliferation, cell cycle regulation, cell differentiation, metabolism, and various physiological characteristics of cells. Although 50/60 Hz EMF do not directly lead to genotoxic effects, it is possible that certain cellular processes altered by exposure to EMF indirectly affect the structure of DNA causing strand breaks and other chromosomal aberrations. The aim of this article is to present a hypothesis of a possible initial cellular event affected by exposure to ELF EMF, an event which is compatible with the multitude of effects observed after exposure. Based on an extensive literature review, we suggest that ELF EMF exposure is able to perform such activation by means of increasing levels of free radicals. Such a general activation is compatible with the diverse nature of observed effects. Free radicals are intermediates in natural processes like mitochondrial metabolism and are also a key feature of phagocytosis. Free radical release is inducible by ionizing radiation or phorbol ester treatment, both leading to genomic instability. EMF might be a stimulus to induce an "activated state" of the cell such as phagocytosis, which then enhances the release of free radicals, in turn leading to genotoxic events. We envisage that EMF exposure can cause both acute and chronic effects that are mediated by increased free radical levels: (1) Direct activation of, for example macrophages (or other cells) by short-term exposure to EMF leads to phagocytosis (or other cell specific responses) and consequently, free radical production. This pathway may be utilized to positively influence certain aspects of the immune response, and could be useful for specific therapeutic applications. (2) EMF-induced macrophage (cell) activation includes direct stimulation of free radical production. (3) An increase in the lifetime of free radicals by EMF leads to persistently elevated free radical concentrations. In general, reactions in which radicals are involved become more frequent, increasing the possibility of DNA damage. (4) Long-term EMF exposure leads to a chronically increased level of free radicals, subsequently causing an inhibition of the effects of the pineal gland hormone melatonin. Taken together, these EMF induced reactions could lead to a higher incidence of DNA damage and therefore, to an increased risk of tumour development. While the effects on melatonin and the extension of the lifetime of radicals can explain the link between EMF exposure and the incidence of for example leukaemia, the two additional mechanisms described here specifically for mouse macrophages, can explain the possible correlation between immune cell system stimulation and EMF exposure.     

The impact of background radiation,illumination and temperature on EMF-induced changes of aqua medium properties

The effects of extremely low frequency electromagnetic field (ELF EMF) on physicochemical properties of physiological solution at different environmental media were studied. The existence of frequency “windows” at 4 and 8 Hz frequencies of ELF EMF having effects on heat fusion period, hydrogen peroxide (H₂O₂) formation and oxygen (O₂) content of water solution and different dependency on temperature, background radiation and illumination was shown. Obtained data allow us to suggest that EMF-induced effect on water physicochemical properties depends on abovementioned environmental factors. As cell bathing medium is a target for biological effects of ELF EMF, the variability of experimental data on biological effects of EMF, obtained in different laboratories, can be explained by different environmental conditions of experiments, which very often are not considered adequately.     

Effects of extremely low frequency electromagnetic fields on health

This paper gives a brief review of the physical interaction and bio-effects of exposure to extremely low frequency (ELF) electromagnetic fields (EMF) along with guidelines on limits of exposure to 50/60 Hz electric and magnetic fields.     

Exposure classification of MRI workers in epidemiological studies

We estimate that there are about 100,000 workers from different disciplines, such as radiographers, nurses, anesthetists, technicians, engineers, etc., who can be exposed to substantial electromagnetic fields (compared to normal background levels) around magnetic resonance imaging (MRI) scanners. There is a need for well‐designed epidemiological studies of MRI workers but since the exposure from MRI equipment is a very complex mixture of static magnetic fields, switched gradient magnetic fields, and radiofrequency electromagnetic fields (RF EMF), it is necessary to discuss how to assess the exposure in epidemiological studies. As an alternative to the use of job title as a proxy of exposure, we propose an exposure categorization for the different professions working with MRI equipment. Specifically, we propose defining exposure in three categories, depending on whether people are exposed to only the static field, to the static plus switched gradient fields or to the static plus switched gradient plus RF fields, as a basis for exposure assessment in epidemiological studies. Bioelectromagnetics 34:81–84, 2013. © 2012 Wiley Periodicals, Inc.     

Neural stimulation on human bone marrow‐derived mesenchymal stem cells by extremely low frequency electromagnetic fields

Adult stem cells are considered multipotent. Especially, human bone marrow‐derived mesenchymal stem cells (hBM‐MSCs) have the potential to differentiate into nerve type cells. Electromagnetic fields (EMFs) are widely distributed in the environment, and recently there have been many reports on the biological effects of EMFs. hBM‐MSCs are weak and sensitive pluripotent stem cells, therefore extremely low frequency‐electromagnetic fields (ELF‐EMFs) could be affect the changes of biological functions within the cells. In our experiments, ELF‐EMFs inhibited the growth of hBM‐MSCs in 12 days exposure. Their gene level was changed and expression of the neural stem cell marker like nestin was decreased but the neural cell markers like MAP2, NEUROD1, NF‐L, and Tau were induced. In immunofluorescence study, we confirmed the expression of each protein of neural cells. And also both oligodendrocyte and astrocyte related proteins like O4 and GFAP were expressed by ELF‐EMFs. We suggest that EMFs can induce neural differentiation in BM‐MSCs without any chemicals or differentiation factors. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012     

Electromagnetic fields and human endocrine system

Extremely low frequency electromagnetic fields (ELF EMF) are commonly present in daily life all over the world. Moreover, EMF are used in the physiotherapy of many diseases because of their beneficial effects. There is widespread public concern that EMF may have potential consequences for human health. Although experimental animal studies indicate that EMF may influence secretion of some hormones, the data on the effects of EMF on human endocrine system are scarce. Most of the results concentrate on influence of EMF on secretion of melatonin. In this review, the data on the influence of EMF on human endocrine system are briefly presented and discussed.     

Short‐term exposure to 50 Hz ELF‐EMF alters the cisplatin‐induced oxidative response in AT478 murine squamous cell carcinoma cells

The aim of this study was to assess the influence of cisplatin and an extremely low frequency electromagnetic field (ELF‐EMF) on antioxidant enzyme activity and the lipid peroxidation ratio, as well as the level of DNA damage and reactive oxygen species (ROS) production in AT478 carcinoma cells. Cells were cultured for 24 and 72 h in culture medium with cisplatin. Additionally, the cells were irradiated with 50 Hz/1 mT ELF‐EMF for 16 min using a solenoid as a source of the ELF‐EMF. The amount of ROS, superoxide dismutase (SOD) isoenzyme activity, glutathione peroxidase (GSH‐Px) activity, DNA damage, and malondialdehyde (MDA) levels were assessed. Cells that were exposed to cisplatin exhibited a significant increase in ROS and antioxidant enzyme activity. The addition of ELF‐EMF exposure to cisplatin treatment resulted in decreased ROS levels and antioxidant enzyme activity. A significant reduction in MDA concentrations was observed in all of the study groups, with the greatest decrease associated with treatment by both cisplatin and ELF‐EMF. Cisplatin induced the most severe DNA damage; however, when cells were also irradiated with ELF‐EMF, less DNA damage occurred. Exposure to ELF‐EMF alone resulted in an increase in DNA damage compared to control cells. ELF‐EMF lessened the effects of oxidative stress and DNA damage that were induced by cisplatin; however, ELF‐EMF alone was a mild oxidative stressor and DNA damage inducer. We speculate that ELF‐EMF exerts differential effects depending on the exogenous conditions. This information may be of value for appraising the pathophysiologic consequences of exposure to ELF‐EMF. Bioelectromagnetics 33:641–651, 2012. © 2012 Wiley Periodicals, Inc.     

Exposure to power frequency magnetic fields suppresses X-ray-induced apoptosis transiently in Ku80-deficient xrs5 cells

In an attempt to determine whether exposure to extremely low frequency (ELF) electromagnetic fields can affect cells, Ku80-deficient cells (xrs5) and Ku80-proficient cells (CHO-K1) were exposed to ELF electromagnetic fields. Cell survival, and the levels of the apoptosis-related genes p21, p53, phospho-p53 (Ser(15)), caspase-3 and the anti-apoptosis gene bcl-2 were determined in xrs5 and CHO-K1 cells following exposure to ELF electromagnetic fields and X-rays. It was found that exposure of xrs5 and CHO-K1 cells to 60 Hz ELF electromagnetic fields had no effect on cell survival, cell cycle distribution and protein expression. Exposure of xrs5 cells to 60 Hz ELF electromagnetic fields for 5 h after irradiation significantly inhibited G(1) cell cycle arrest induced by X-rays (1 Gy) and resulted in elevated bcl-2 expression. A significant decrease in the induction of p53, phospho-p53, caspase-3 and p21 proteins was observed in xrs5 cells when irradiation by X-rays (8 Gy) was followed by exposure to 5 mT ELF magnetic fields. Exposure of xrs5 cells to the ELF electromagnetic fields for 10 h following irradiation significantly decreased X-ray-induced apoptosis from about 1.7% to 0.7%. However, this effect was not found in CHO-K1 cells within 24 h of irradiation by X-rays alone and by X-rays combined with ELF electromagnetic fields. Exposure of xrs5 cells to 60 Hz ELF electromagnetic fields following irradiation can affect cell cycle distribution and transiently suppress apoptosis by decreasing the levels of caspase-3, p21, p53 and phospho-p53 and by increasing bcl-2 expression.     

Idiopathic environmental intolerance attributed to electromagnetic fields (formerly ‘electromagnetic hypersensitivity’): An updated systematic review of provocation studies

Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI‐EMF; formerly ‘electromagetic hypersensitivity’) is a medically unexplained illness in which subjective symptoms are reported following exposure to electrical devices. In an earlier systematic review, we reported data from 31 blind provocation studies which had exposed IEI‐EMF volunteers to active or sham electromagnetic fields and assessed whether volunteers could detect these fields or whether they reported worse symptoms when exposed to them. In this article, we report an update to that review. An extensive literature search identified 15 new experiments. Including studies reported in our earlier review, 46 blind or double‐blind provocation studies in all, involving 1175 IEI‐EMF volunteers, have tested whether exposure to electromagnetic fields is responsible for triggering symptoms in IEI‐EMF. No robust evidence could be found to support this theory. However, the studies included in the review did support the role of the nocebo effect in triggering acute symptoms in IEI‐EMF sufferers. Despite the conviction of IEI‐EMF sufferers that their symptoms are triggered by exposure to electromagnetic fields, repeated experiments have been unable to replicate this phenomenon under controlled conditions. A narrow focus by clinicians or policy makers on bioelectromagnetic mechanisms is therefore, unlikely to help IEI‐EMF patients in the long‐term. Bioelectromagnetics 31:1–11, 2010. © 2009 Wiley‐Liss, Inc.     

Hypothesis: The risk of childhood leukemia is related to combinations of power-frequency and static magnetic fields

We present a hypothesis that the risk of childhood leukemia is related to exposure to specific combinations of static and extremely-low-frequency (ELF) magnetic fields. Laboratory data from calcium efflux and diatom mobility experiments were used with the gyromagnetic equation to predict combinations of 60 Hz and static magnetic fields hypothesized to enhance leukemia risk. The laboratory data predicted 19 bands of the static field magnitude with a bandwidth of 9.1 μT that, together with 60 Hz magnetic fields, are expected to have biological activity. We then assessed the association between this exposure metric and childhood leukemia using data from a case-control study in Los Angeles County. ELF and static magnetic fields were measured in the bedrooms of 124 cases determined from a tumor registry and 99 controls drawn from friends and random digit dialing. Among these subjects, 26 cases and 20 controls were exposed to static magnetic fields lying in the predicted bands of biological activity centered at 38.0 μT and 50.6 μT. Although no association was found for childhood leukemia in relation to measured ELF or static magnetic fields alone, an increasing trend of leukemia risk with measured ELF fields was found for subjects within these static field bands (P for trend = 0.041). The odds ratio (OR) was 3.3 [95% confidence interval (CI) = 0.4–30.5] for subjects exposed to static fields within the derived bands and to ELF magnetic field above 0.30 μT (compared to subjects exposed to static fields outside the bands and ELF magnetic fields below 0.07 μT). When the 60 Hz magnetic fields were assessed according to the Wertheimer-Leeper code for wiring configurations, leukemia risks were again greater with the hypothesized exposure conditions (OR = 9.2 for very high current configurations within the static field bands: 95% CI = 1.3–64.6). Although the risk estimates are based on limited magnetic field measurements for a small number of subjects, these findings suggest that the risk of childhood leukemia may be related to the combined effects of the static and ELF magnetic fields. Further tests of the hypothesis are proposed. © 1995 Wiley-Liss, Inc.