27/02/2012 - February 2012 - Science Update

The following is a quick summary of another twenty papers that have come out over the last few months related to effects of electromagnetic radiation. Some of the papers are notable papers that have been published very recently, others are papers that were published a few months ago that have not yet made it to one of the Science Updates.

This study examined radiofrequency (RF) emissions from smart electric power meters deployed in two service territories in California for the purpose of evaluating potential human exposure. These meters included transmitters operating in a local area mesh network (RF LAN, ˜250 mW); a cell relay, which uses a wireless wide area network (WWAN, ˜1 W); and a transmitter serving a home area network (HAN, ˜70 mW). In all instances, RF fields were found to comply by a wide margin with the RF exposure limits established by the US Federal Communications Commission. The study included specialised measurement techniques and reported the spatial distribution of the fields near the meters and their duty cycles (typically <1 %) whose value is crucial to assessing time-averaged exposure levels. This study is the first to characterise smart meters as deployed. However, the results are restricted to a single manufacturer's emitters.

Extremely low frequency electromagnetic fields (ELF-EMF) have been found to produce a variety of biological effects. These effects of ELF-EMF depend upon frequency, amplitude, and length of exposure, And are also related to intrinsic susceptibility and responsiveness of different cell types. Although the mechanism of this interaction is still obscure ELF-EMF can influence cell proliferation, differentiation, cell cycle, apoptosis, DNA replication and protein expression. The aim of this study was to estimate various kinetic constants of catalase, cytochrome P450 and inducible nitric oxide synthase in response to ELF-EMF exposure in human HaCaT and THP-1 cell lines. In order to evaluate the effect of ELF-EMF on the modulation of cellular responses to an inflammatory stimulus, both cell lines were treated with lipopolysaccharide. To the best of our knowledge there is no available report on such type of kinetic study of selected enzymes in response to ELF-EMF in these cell lines. Therefore, the current study may reveal novel mechanism of ELF-EMF biological interaction with the enzymological and hormonal systems of living organisms. These new insights may be important for ELF-EMF application particularly for wound healing, tissue regeneration, and Parkinson's and Alzheimer's diseases.

A radiofrequency (RF) electromagnetic radiation safety survey had been carried out at public access points in 46 towns with 76 Global Systems for Mobile communication cell sites in two major cities in Ghana. The objective was to determine the levels of RF field in residential areas, schools and market places, and compare the measured results with the guidelines set by the International Commission of Non-Ionising Radiation (ICNIRP). Measurements were made with log-periodic antenna coupled with spectrum analyzer. The results varied from 0.85 to 1.07 mW m(-2) and 0.78 to 1.19 mW m(-2) for the transmission frequencies of 900 and 1800 MHz, respectively. The result generally shows a compliance with the ICNIRP limit of 0.024 % but was 108 times higher than a similar survey carried out in Ghana 2 y ago.

Case-control studies on adults point to an increased risk of brain tumours (glioma and acoustic neuroma) associated with the long-term use of mobile phones. Recently, the first study on mobile phone use and the risk of brain tumours in children and adolescents, CEFALO, was published. It has been claimed that this relatively small study yielded reassuring results of no increased risk. We do not agree. We consider that the data contain several indications of increased risk, despite low exposure, short latency period, and limitations in the study design, analyses and interpretation. The information certainly cannot be used as reassuring evidence against an association, for reasons that we discuss in this commentary.

Some case-control studies have reported increased risks of glioma associated with mobile phone use. If true, this would ultimately affect the time trends for incidence rates (IRs). Correspondingly, lack of change in IRs would exclude certain magnitudes of risk. We investigated glioma IR trends in the Nordic countries, and compared the observed with expected incidence rates under various risk scenarios. We analyzed annual age-standardized incidence rates in men and women aged 20 to 79 years during 1979-2008 using joinpoint regression (35,250 glioma cases). Probabilities of detecting various levels of relative risk were computed using simulations. For the period 1979 through 2008, the annual percent change in incidence rates was 0.4% (95% confidence interval = 0.1% to 0.6%) among men and 0.3% (0.1% to 0.5%) among women. Incidence rates have decreased in young men (20-39 years) since 1987, remained stable in middle-aged men (40-59 years) throughout the 30-year study period, and increased slightly in older men (60-79 years). In simulations, assumed relative risks for all users of 2.0 for an induction time of up to 15 years, 1.5 for up to 10 years, and 1.2 for up to 5 years were incompatible with observed incidence time trends. For heavy users of mobile phones, risks of 2.0 for up to 5 years' induction were also incompatible. No clear trend change in glioma incidence rates was observed. Several of the risk increases seen in case-control studies appear to be incompatible with the observed lack of incidence rate increase in middle-aged men. This suggests longer induction periods than currently investigated, lower risks than reported from some case-control studies, or the absence of any association.

Funding is needed for further medical and basic science research to identify and characterise the biological influence that amplitude-modulated EMFs have on the body, in its normal state, when recovering from disease or injury, and when initially affected by disease. As a caution, 'information content' EMF signals may not always have beneficial consequences for humans or their environment, so research should examine potential detrimental biological outcomes as well.

The group of three papers demonstrate a new, potentially important modality in the treatment of cancer that could lead to a paradigm shift in disease treatment. I hope that this medical application of AM-EMF will not be allowed languish without funding, as happened with its previous, ill-fated emergence.

The existing cell phone certification process uses a plastic model of the head called the Specific Anthropomorphic Mannequin (SAM), representing the top 10% of U.S. military recruits in 1989 and greatly underestimating the Specific Absorption Rate (SAR) for typical mobile phone users, especially children. A superior computer simulation certification process has been approved by the Federal Communications Commission (FCC) but is not employed to certify cell phones. In the United States, the FCC determines maximum allowed exposures. Many countries, especially European Union members, use the "guidelines" of International Commission on Non-Ionizing Radiation Protection (ICNIRP), a non governmental agency. Radiofrequency (RF) exposure to a head smaller than SAM will absorb a relatively higher SAR. Also, SAM uses a fluid having the average electrical properties of the head that cannot indicate differential absorption of specific brain tissue, nor absorption in children or smaller adults. The SAR for a 10-year old is up to 153% higher than the SAR for the SAM model. When electrical properties are considered, a child's head's absorption can be over two times greater, and absorption of the skull's bone marrow can be ten times greater than adults. Therefore, a new certification process is needed that incorporates different modes of use, head sizes, and tissue properties. Anatomically based models should be employed in revising safety standards for these ubiquitous modern devices and standards should be set by accountable, independent groups.

In situ radiofrequency (RF) exposure of the different RF sources is characterized in Reading, United Kingdom, and an extrapolation method to estimate worst-case long-term evolution (LTE) exposure is proposed. All electric field levels satisfy the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels with a maximal total electric field value of 4.5 V/m. The total values are dominated by frequency modulation (FM). Exposure levels for LTE of 0.2 V/m on average and 0.5 V/m maximally are obtained. Contributions of LTE to the total exposure are limited to 0.4% on average. Exposure ratios from 0.8% (LTE) to 12.5% (FM) are obtained. An extrapolation method is proposed and validated to assess the worst-case LTE exposure. For this method, the reference signal (RS) and secondary synchronization signal (S-SYNC) are measured and extrapolated to the worst-case value using an extrapolation factor. The influence of the traffic load and output power of the base station on in situ RS and S-SYNC signals are lower than 1 dB for all power and traffic load settings, showing that these signals can be used for the extrapolation method. The maximal extrapolated field value for LTE exposure equals 1.9 V/m, which is 32 times below the ICNIRP reference levels for electric fields.

Recently, many studies have been carried out in relation to 900 MHz radiofrequency radiation (RF) emitted from a mobile phone on the brain. However, there is little data concerning possible mechanisms between long-term exposure of RF radiation and biomolecules in brain. Therefore, we aimed to investigate long-term effects of 900 MHz radiofrequency radiation on beta amyloid protein, protein carbonyl, and malondialdehyde in the rat brain. The study was carried out on 17 Wistar Albino adult male rats. The rat heads in a carousel were exposed to 900 MHz radiofrequency radiation emitted from a generator, simulating mobile phones. For the study group (n: 10), rats were exposed to the radiation 2 h per day (7 days a week) for 10 months. For the sham group (n: 7), rats were placed into the carousel and the same procedure was applied except that the generator was turned off. In this study, rats were euthanized after 10 months of exposure and their brains were removed. Beta amyloid protein, protein carbonyl, and malondialdehyde levels were found to be higher in the brain of rats exposed to 900 MHz radiofrequency radiation. However, only the increase of protein carbonyl in the brain of rats exposed to 900 MHz radiofrequency radiation was found to be statistically significant (p < 0.001). In conclusion, 900 MHz radiation emitted from mobile/cellular phones can be an agent to alter some biomolecules such as protein. However, further studies are necessary.

The potential effects of a chronic exposure to magnetic fields on blood chemistry in humans were tested. We examined the nocturnal profiles and levels of the following blood parameters: electrolytes (sodium, potassium, chloride, calcium, magnesium, phosphorus), nonprotein nitrogenous compounds (uric acid urea, creatinine), and glucose, in 15 men (38.0±0.9years) exposed chronically and daily for a period of 1-20years, in the workplace and at home, to a 50-Hz magnetic field in search of any cumulative effect from those chronic conditions of exposure. The weekly geometric mean of individual exposures ranged from 0.1 to 2.6 µT. The results are compared to those obtained in our control group: 15 unexposed men of similar age (39.4±1.2years), with the same synchronization and physical activity that served as controls (individual exposures ranged from 0.004 to 0.092 µT). Blood samples were taken hourly from 20:00h to 08:00h. This work shows that subjects exposed over a long period (up to 20 years) and on a daily basis to magnetic fields experienced significant changes in serum sodium, chloride, phosphorus and glucose where an effect for field-hour interaction was noted for exposures greater than 0.3 µT. Our data suggest that long-term exposure to 50-Hz magnetic fields (exposure >0.3 µT) in healthy men could induce some biological modifications of certain blood parameters, though their clinical relevance needs further investigation.

The reason for hyper magnetosensitivity of young animals compared to older ones remains unclear. It has been suggested that age-induced tissue dehydration (decreased water content) could be a basis for the aging-related decrease in the organism's magnetosensitivity. To test this hypothesis, the effect of a 0.2 T static magnetic field (SMF) exposure on heart muscle hydration in three age groups of rats (young, adult, and older) was studied, with and without ouabain poisoning. The SMF exposure resulted in heart muscle dehydration of young (21%) and adult (6.2%) rats but had no effect on older animals. In young animals without ouabin poisoning, SMF exposure caused dehydration of the heart muscle while in the ouabain-poisoned animals it led to hydration (29.6%). These hydration effects were more pronounced in young animals than in adult and older animals. The increased hydration (5.7%) of heart muscles in older animals was evoked by providing distilled water for seven days, which elevated (by 12%) the SMF-induced heart muscle hydration effect. These results suggest that the hyper magnetosensitivity of the young heart muscle and the lower sensitivity of older animals are due to initial high (83.5%) and low (75.3%) tissue hydration levels, respectively. Therefore, the age-induced decrease in the magnetosensitivity of heart muscle is likely to be a result of Na(+) /K(+) pump dysfunction.

The objective of this study was to investigate the effects of two sources of electromagnetic fields (EMFs) on the proteome of cerebellum, hippocampus, and frontal lobe in Balb/c mice following long-term whole body irradiation. Three equally divided groups of animals (6 animals/group) were used; the first group was exposed to a typical mobile phone, at a SAR level range of 0.17-0.37 W/kg for 3 h daily for 8 months, the second group was exposed to a wireless DECT base (Digital Enhanced Cordless Telecommunications/Telephone) at a SAR level range of 0.012-0.028 W/kg for 8 h/day also for 8 months and the third group comprised the sham-exposed animals. Comparative proteomics analysis revealed that long-term irradiation from both EMF sources altered significantly (p < 0.05) the expression of 143 proteins in total (as low as 0.003 fold downregulation up to 114 fold overexpression). Several neural function related proteins (i.e., Glial Fibrillary Acidic Protein (GFAP), Alpha-synuclein, Glia Maturation Factor beta (GMF), and apolipoprotein E (apoE)), heat shock proteins, and cytoskeletal proteins (i.e., Neurofilaments and tropomodulin) are included in this list as well as proteins of the brain metabolism (i.e., Aspartate aminotransferase, Glutamate dehydrogenase) to nearly all brain regions studied. Western blot analysis on selected proteins confirmed the proteomics data. The observed protein expression changes may be related to brain plasticity alterations, indicative of oxidative stress in the nervous system or involved in apoptosis and might potentially explain human health hazards reported so far, such as headaches, sleep disturbance, fatigue, memory deficits, and brain tumor long-term induction under similar exposure conditions. Dariusz Leszczynski has made a detailed commentary of this study on his blog.

The transduction mechanism for non-thermal electromagnetic field (EMF) bioeffects has not been fully elucidated. This study proposes that an EMF can act as a first messenger in the calmodulin-dependent signaling pathways that orchestrate the release of cytokines and growth factors in normal cellular responses to physical and/or chemical insults. Given knowledge of Ca(2+) binding kinetics to calmodulin (CaM), an EMF signal having pulse duration or carrier period shorter than bound Ca(2+) lifetime may be configured to accelerate binding, and be detectable above thermal noise. New EMF signals were configured to modulate calmodulin-dependent signaling and assessed for efficacy in cellular studies. Configured EMF signals modulated CaM-dependent enzyme kinetics, produced several-fold increases in key second messengers to include nitric oxide and cyclic guanosine monophosphate in chondrocyte and endothelial cultures and cyclic adenosine monophosphate in neuronal cultures. Calmodulin antagonists and downstream blockers annihilated these effects, providing strong support for the proposed mechanism. Knowledge of the kinetics of Ca(2+) binding to CaM, or for any ion binding specific to any signaling cascade, allows the use of an electrochemical model by which the ability of any EMF signal to modulate CaM-dependent signaling can be assessed a priori or a posteriori. Results are consistent with the proposed mechanism, and strongly support the Ca/CaM/NO pathway as a primary EMF transduction pathway. The predictions of the proposed model open a host of significant possibilities for configuration of non-thermal EMF signals for clinical and wellness applications that can reach far beyond fracture repair and wound healing.

Several studies have been using a GSM mobile phone in stand-by mode as the source for exposure, and they claimed that this caused effects on for instance sleep and testicular function. In stand-by mode the phone is only active in periodic location updates, and this occurs with a frequency set by the net operator. Typical updates occur with 2-5 h in between, and between these updates the phone is to be considered as a passive radio receiver with no microwave emission. Thus, the exposure in stand-by mode can be considered negligible.

We examined and monitored a dairy farm in which a large number of calves were born with nuclear cataracts after a mobile phone base station had been erected in the vicinity of the barn. Calves showed a 3.5 times higher risk for heavy cataract if born there compared to Swiss average. All usual causes such as infection or poisoning, common in Switzerland, could be excluded. The real cause of the increased incidence of cataracts remains unknown.

Iron surcharge may induce an oxidative stress-based decline in several neurological functions. In addition, electromagnetic fields (EMF) of frequencies up to about 100 kHz, emitted by electric/electronic devices, have been suggested to enhance free radical production through an iron dependent pathway. The purpose of this study was therefore to determine a possible relationship between iron status, exposure to EMF, and brain oxidative stress in young adult rats. Samples were micro-dissected from prefrontal cortex, hippocampus, striatum, and cerebellum after chronic saline or iron overload (IO) as well as after chronic sham exposure or exposure to a 150 kHz EMF or after combining EMF exposure with IO. The brain samples were used to monitor oxidative stress-induced lipid peroxidation and activity of the antioxidant enzymes superoxide dismutase and catalase. While IO did not induce any oxidative stress in young adult rats, it stimulated antioxidant defenses in the cerebellum and prefrontal cortex in particular. On the contrary, EMF exposure stimulated lipid peroxidation mainly in the cerebellum, without affecting antioxidant defenses. When EMF was coapplied with IO, lipid peroxidation was further increased as compared to EMF alone while the increase in antioxidant defenses triggered by the sole IO was abolished. These data suggest that EMF exposure may be harmful in young adults by impairing the antioxidant defenses directed at preventing iron-induced oxidative stress.

We sought direct evidence that acute exposure to environmental-strength electromagnetic fields (EMFs) could induce somatic reactions (EMF hypersensitivity). The subject, a female physician self-diagnosed with EMF hypersensitivity, was exposed to an average (over the head) 60-Hz electric field of 300 V/m (comparable with typical environmental-strength EMFs) during controlled provocation and behavioral studies. In a double-blinded EMF provocation procedure specifically designed to minimize unintentional sensory cues, the subject developed temporal pain, headache, muscle twitching, and skipped heartbeats within 100 s after initiation of EMF exposure (p < .05). The symptoms were caused primarily by field transitions (off-on, on-off) rather than the presence of the field, as assessed by comparing the frequency and severity of the effects of pulsed and continuous fields in relation to sham exposure. The subject had no conscious perception of the field as judged by her inability to report its presence more often than in the sham control. The subject demonstrated statistically reliable somatic reactions in response to exposure to subliminal EMFs under conditions that reasonably excluded a causative role for psychological processes. EMF hypersensitivity can occur as a bona fide environmentally inducible neurological syndrome.

The increasing use of cellular phones in our society has brought focus on the potential detrimental effects to human health by microwave radiation. The aim of our study was to evaluate the intensity of oxidative stress and the level of neurotransmitters in the brains of fetal rats chronically exposed to cellular phones. The experiment was performed on pregnant rats exposed to different intensities of microwave radiation from cellular phones. Thirty-two pregnant rats were randomly divided into four groups: CG, GL, GM, and GH. CG accepted no microwave radiation, GL group radiated 10 min each time, GM group radiated 30 min, and GH group radiated 60 min. The 3 experimental groups were radiated 3 times a day from the first pregnant day for consecutively 20 days, and on the 21st day, the fetal rats were taken and then the contents of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), noradrenaline (NE), dopamine (DA), and 5-hydroxyindole acetic acid (5-HT) in the brain were assayed. Compared with CG, there were significant differences (P < 0.05) found in the contents of SOD, GSH-Px, and MDA in GM and GH; the contents of SOD and GSH-Px decreased and the content of MDA increased. The significant content differences of NE and DA were found in fetal rat brains in GL and GH groups, with the GL group increased and the GH group decreased. Through this study, we concluded that receiving a certain period of microwave radiation from cellular phones during pregnancy has certain harm on fetal rat brains.

A novel exposure system for double-blind human electromagnetic provocation studies has been developed that satisfies the precision, control of fields and potential artifacts, and provides the flexibility to investigate the response of hypotheses-driven electromagnetic field exposure schemes on brain function, ranging from extremely low frequency (ELF) to radio frequency (RF) fields. The system can provide the same exposure of the lateral cerebral cortex at two different RF frequencies (900 and 2140 MHz) but with different exposure levels at subcortical structures, and also allows uniform ELF magnetic field exposure of the brain. The RF modulation and ELF signal are obtained by a freely programmable arbitrary signal generator allowing a wide range of worst-case exposure scenarios to be simulated, including those caused by wireless devices. The maximum achievable RF exposure is larger than 60 W/kg peak spatial specific absorption rate averaged over 10 g of tissue. The maximum ELF magnetic field exposure of the brain is 800 A/m at 50 Hz with a deviation from uniformity of 8% (SD).

To analyze the short term effects of radiofrequency radiation (RFR) exposure on genomic deoxyribonucleic acid (DNA) of human hair root cells. Hair samples were collected from 8 healthy human subjects immediately before and after using a 900-MHz GSM (Global System for Mobile Communications) mobile phone for 15 and 30 minutes. Single-strand DNA breaks of hair root cells from the samples were determined using the 'comet assay'. The data showed that talking on a mobile phone for 15 or 30 minutes significantly increased (p < .05) single-strand DNA breaks in cells of hair roots close to the phone. Comparing the 15-min and 30-min data using the paired t-test also showed that significantly more damages resulted after 30 minutes than after 15 minutes of phone use. A short-term exposure (15 and 30 minutes) to RFR (900-MHz) from a mobile phone caused a significant increase in DNA single-strand breaks in human hair root cells located around the ear which is used for the phone calls.