29/09/2010 - September 2010 - 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.

We aimed to investigate the effects of weak extremely low frequency electromagnetic fields (ELF-EMFs) on the nucleus size, the silver staining nucleolar organizer regions (AgNORs), the frequency of micro nucleated peripheral blood lymphocytes (MPBLs) and the micro nucleated polychromatic erythrocytes (MPCEs). One hundred and twenty Swiss albino mice were equally divided into 6 groups. The study groups were exposed to 1, 2, 3, 4 and 5 microT 50 Hz-EMFs for 40 days. Micronucleus number (MN) per PBL was determined. ELF-EMF exposure caused a nonlinear decline of nucleus area. A sharp drop occurred in AgNOR area of 1 microT group, and following it gained an insignificantly higher level than that of the control group. The field did not change mean AgNOR numbers per nucleus of the groups. Relative AgNOR area had the highest level in 1 microT-exposure group, and the level was quite similar to that of the 5 microT-exposure group. The remaining groups had significantly lower values quite similar to that of the control level. The field exposure at any intensity did not affect significantly the frequency of either MPBLs or MPCEs. The number of MN per PBL in the 4 and 5 microT-exposure groups were significantly higher than those of the lower intensity exposure groups. The males in 4 microT-exposure group displayed the highest MN number per PBL, whereas values changed in a nonlinear manner. The results of the present study suggest that </=5 microT intensities of 50 Hz EMFs did not cause genotoxic effect on the mouse.

The rapid increase in mobile telephone use has generated concern about possible health risks related to radiofrequency electromagnetic fields from this technology. An interview-based case-control study with 2708 glioma and 2409 meningioma cases and matched controls was conducted in 13 countries using a common protocol. A reduced odds ratio (OR) related to ever having been a regular mobile phone user was seen for glioma [OR 0.81; 95% confidence interval (CI) 0.70-0.94] and meningioma (OR 0.79; 95% CI 0.68-0.91), possibly reflecting participation bias or other methodological limitations. No elevated OR was observed > or =10 years after first phone use (glioma: OR 0.98; 95% CI 0.76-1.26; meningioma: OR 0.83; 95% CI 0.61-1.14). ORs were < 1.0 for all deciles of lifetime number of phone calls and nine deciles of cumulative call time. In the 10th decile of recalled cumulative call time, > or =1640 h, the OR was 1.40 (95% CI 1.03-1.89) for glioma, and 1.15 (95% CI 0.81-1.62) for meningioma; but there are implausible values of reported use in this group. ORs for glioma tended to be greater in the temporal lobe than in other lobes of the brain, but the CIs around the lobe-specific estimates were wide. ORs for glioma tended to be greater in subjects who reported usual phone use on the same side of the head as their tumour than on the opposite side. Overall, no increase in risk of glioma or meningioma was observed with use of mobile phones. There were suggestions of an increased risk of glioma at the highest exposure levels, but biases and error prevent a causal interpretation. The possible effects of long-term heavy use of mobile phones require further investigation. The latest state of play regarding the data from the international INTERPHONE project summarises in a way that many of the papers have - short term use doesn't seem to have an effect on brain tumours, but there is still a big question mark over long term usage. We covered this paper and its ramifications in greater detail in our two INTERPHONE stories in May 2010, one published on the 14th and the other published on the 18th.

Not surprisingly, we end by calling for more research, given the increasingly ubiquitous use of mobile phones, rising use by children and the indication from some studies, including the INTERPHONE study, that mobile phone use may increase risk for brain tumours.

The development of new wireless communication technologies that emit radio frequency electromagnetic fields (RF-EMF) is ongoing, but little is known about the RF-EMF exposure distribution in the general population. Previous attempts to measure personal exposure to RF-EMF have used different measurement protocols and analysis methods making comparisons between exposure situations across different study populations very difficult. As a result, observed differences in exposure levels between study populations may not reflect real exposure differences but may be in part, or wholly due to methodological differences. The aim of this paper is to develop a study protocol for future personal RF-EMF exposure studies based on experience drawn from previous research. Using the current knowledge base, we propose procedures for the measurement of personal exposure to RF-EMF, data collection, data management and analysis, and methods for the selection and instruction of study participants. We have identified two basic types of personal RF-EMF measurement studies: population surveys and microenvironmental measurements. In the case of a population survey, the unit of observation is the individual and a randomly selected representative sample of the population is needed to obtain reliable results. For microenvironmental measurements, study participants are selected in order to represent typical behaviours in different microenvironments. These two study types require different methods and procedures. Applying our proposed common core procedures in future personal measurement studies will allow direct comparisons of personal RF-EMF exposures in different populations and study areas.

Animals from a wide range of taxa have been shown to possess magnetic sense and use magnetic compasses to orient; however, there is no information in the literature on whether lizards have either of these abilities. In this study, we investigated the behavioral responses of a diurnal agamid lizard (Pogona vitticeps) to a sinusoidal extremely low-frequency electromagnetic field (ELF-EMF; 6 and 8 Hz, peak magnetic field 2.6 microT, peak electric field 10 V m(-1)). Fourteen adult lizards were divided randomly into two groups (the EMF and control groups; each group had three males and four females). The EMF group received whole-body exposure to ELF-EMF and the control group did not. Lizards in the EMF group were exposed to ELF-EMF for 12 h per day (during the light period). The number of tail lifts was monitored beginning 3 days before exposure and ending after 5 days of exposure. For each individual, the average number of tail lifts per day was calculated. The average number of tail lifts per individual per day was greater in the EMF group than in the control group (20.7+/-6.3 and 9.1+/-4.5 tail lifts, respectively, N=7 each, P=0.02). We confirmed the reproducibility of this response by a cross-over trial. These results suggest that at least some lizards are able to perceive ELF-EMFs. Furthermore, when the parietal eye of the lizards was covered with a small round aluminum 'cap' which could block light, the tail-lifting response to ELF-EMF disappeared. Our experiments suggest that (1) lizards perceive EMFs and (2) the parietal eye may be involved in light-dependent magnetoreceptive responses. Although appearing to be rather out of left field, this is another paper that demonstrates the evolutionary adaption of certain animals to be sensitive to electromagnetic fields via mechanisms that are simply not understood.

It is by now accepted that extremely low frequency electromagnetic fields ELF-EMF (0-300 Hz) affect biological systems although the mechanism has not been elucidated yet. In this study the effect of ELFEMF on the number of apoptotic cells of K562 human leukemia cell line induced or not with oxidative stress and the correlation with heat-shock protein 70 (hsp70) levels was investigated. One sample was treated with water while the other was left untreated. ELF-EMF (1 mT, 50 Hz) was applied for 3 hours. ELF-EMF alone caused a decrease in the number of apoptotic cells and a slight increase in viability. However, it increased the number of apoptotic cells. In cells treated with water, hsp70 and reactive oxygen species (ROS) levels were increased by ELF-EMF. These results show that the effect of ELF-EMF on biological systems depends on the status of the cell: while in cells not exposed to oxidative stress it is able to decrease the number of apoptotic cells by inducing an increase in hsp levels, it increases the number of apoptotic cells in oxidative stress-induced cells.

Background: Electric and magnetic fields (EMF) might be involved in human disease and numerous research and scientific reviews have been conducted to address this question. In particular thyroid structural and functional alterations caused by various forms of non-ionizing radiation have been described. Aim: The aim of this study was to analyzed the possible effects of EMFs on thyroid, in particular we analyzed the effects caused by a GSM signal (900 MHz) on cultured thyroid cells (FRTL-5). Material and methods: The experimental setup was designed in order to expose samples to radiofrequency wave in well controlled conditions. We used the FRTL-5 cell line, an epithelial monoclonal continuous cell line derived from Fisher rat thyroid tissue growing as monolayer, expressing the TSH receptor and the sodium-iodide symporter (NIS). FRTL-5 were subsequently irradiate for 24, 48 and 96 hours with EMF (800-900 MHz, power-frequency of mobile communication systems) and iodide uptake and cAMP production were measured. Results: The irradiation of cells with EMF at 900Mhz for 24, 48 and 96 hours did not influence the level of cAMP production and was not able to modify iodide accumulation in FRTL5 cells with respect to basal conditions. Conclusions: In conclusion, EMFs do not seem to be able to interfere with the biochemical properties of FRTL-5 cells in vitro. With the wording of some parts of the abstract, we would be keen to get hold of a copy of this paper and see if the signal was actually a GSM exposure or a CW 900 MHz exposure. Nevertheless, this comment shouldn't be viewed as a disagreement with the findings of the paper itself.

The mammalian blood-brain barrier (BBB) consists of endothelial cells, linked by tight junctions, and the adjoining pericytes and extracellular matrix. It helps maintain a highly stable extracellular environment necessary for accurate synaptic transmission and protects nervous tissue from injury. An increase in its normally low permeability for hydrophilic and charged molecules could potentially be detrimental. Methods to assess the permeability of the BBB include histological staining for marker molecules in brain sections and measurement of the concentration of marker molecules in blood and brain tissue. Their advantages and disadvantages are discussed. Exposure to levels of radiofrequency electromagnetic fields (EMF) that increase brain temperature by more than 1°C can reversibly increase the permeability of the BBB for macromolecules. The balance of experimental evidence does not support an effect of 'non-thermal' radiofrequency fields with microwave and mobile phone frequencies on BBB permeability. Evidence for an effect of the EMF generated by magnetic resonance imaging on permeability is conflicting and conclusions are hampered by potential confounders and simultaneous exposure to different types and frequencies of EMF. The literature on effects of low frequency EMF, which do not cause tissue heating, is sparse and does not yet permit any conclusions on permeability changes. Studies on the potential effect of EMF exposure on permeability of the BBB in humans are virtually absent. Future permeability studies should focus on low frequency effects and effects in humans. Care should be taken to avoid the methodological limitations of earlier studies and to determine the pathophysiological relevance of any changes found. This is a useful paper investigating some of the conflicts and issues surrounding the research into blood brain barrier effects. It is good to see a concrete recommendation that BBB research should be directly undertaken on real life expected exposures in humans.

Exponential interindividual handling in wireless communication system has raised possible doubts in the biological aspects of radiofrequency (RF) exposure on human brain owing to its close proximity to the mobile phone. In the nervous system, calcium (Ca(2+)) plays a critical role in releasing neurotransmitters, generating action potential and membrane integrity. Alterations in intracellular Ca(2+) concentration trigger aberrant synaptic action or cause neuronal apoptosis, which may exert an influence on the cellular pathology for learning and memory in the hippocampus. Calcium binding proteins like calbindin D28-K (CB) is responsible for the maintaining and controlling Ca(2+) homeostasis. Therefore, in the present study, we investigated the effect of RF exposure on rat hippocampus at 835 MHz with low energy (specific absorption rate: SAR=1.6 W/kg) for 3 months by using both CB and glial fibrillary acidic protein (GFAP) specific antibodies by immunohistochemical method. Decrease in CB immunoreactivity (IR) was noted in exposed (E1.6) group with loss of interneurons and pyramidal cells in CA1 area and loss of granule cells. Also, an overall increase in GFAP IR was observed in the hippocampus of E1.6. By TUNEL assay, apoptotic cells were detected in the CA1, CA3 areas and dentate gyrus of hippocampus, which reflects that chronic RF exposure may affect the cell viability. In addition, the increase of GFAP IR due to RF exposure could be well suited with the feature of reactive astrocytosis, which is an abnormal increase in the number of astrocytes due to the loss of nearby neurons. Chronic RF exposure to the rat brain suggested that the decrease of CB IR accompanying apoptosis and increase of GFAP IR might be morphological parameters in the hippocampus damages.

The World Health Organisation proposed an investigation concerning the exposure of animals to radiofrequency fields because of the possible risk factor for health. At power frequencies there is evidence to associate both childhood leukaemia and brain tumours with magnetic field exposures. There is also evidence of the effect of mobile phone exposure on both cognitive functions and the cerebellum. Purkinje cells of the cerebellum are also sensitive to high dose microwave exposure in rats. The present study investigated the effect of exposure to mobile phone on the number of Purkinje and granule neurons in the developing cerebellum. Male and female Swiss albino mice were housed as control and mobile phone-exposed groups. Pregnant animals in the experimental group were exposed to Global System for Mobile Communication (GSM) mobile phone radiation at 890-915 MHz at 0.95 W/Kg specific absorption rate (SAR). The cerebella were processed by frozen microtome. The sections obtained were stained with Haematoxylin-eosin and cresyl violet. For cell counting by the optical fractionator method, a pilot study was firstly performed. Cerebellar areas were analysed by using Axiovision software running on a personal computer. The optical dissectors were systematically spaced at random, and focused to the widest profile of the neuron cell nucleus. A significant decrease in the number of Purkinje cells and a tendency for granule cells to increase in cerebellum was found. Further studies in this area are needed due to the popular use of mobile telephones and relatively high exposure on developing brain. This is a potentially concerning in utero exposure and brain development of the foetus. It is not likely to be possible to replicate this work on humans directly, and as always it is hard to be sure of validity of extrapolating a rat model onto humans, but the possibility of brain development issues in children where the mother had a high phone usage may be very hard to detect in society despite a high potential impact.

To investigate the risk of early childhood cancers associated with the mother's exposure to radiofrequency from and proximity to macrocell mobile phone base stations (masts) during pregnancy, we carried out a case-control study using the cancer registry and national birth register data in Great Britain. We collected 1397 cases of cancer in children aged 0-4 from national cancer registry 1999-2001 and 5588 birth controls from national birth register, individually matched by sex and date of birth (four controls per case). Incidence of cancers of the brain and central nervous system, leukaemia, and non-Hodgkin's lymphomas, and all cancers combined, adjusted for small area measures of education level, socioeconomic deprivation, population density, and population mixing. Mean distance of registered address at birth from a macrocell base station, based on a national database of 76,890 base station antennas in 1996-2001, was similar for cases and controls (1107 (SD 1131) m v 1073 (SD 1130) m, P=0.31), as was total power output of base stations within 700 m of the address (2.89 (SD 5.9) kW v 3.00 (SD 6.0) kW, P=0.54) and modelled power density (-30.3 (SD 21.7) dBm v -29.7 (SD 21.5) dBm, P=0.41). For modelled power density at the address at birth, compared with the lowest exposure category the adjusted odds ratios were 1.01 (95% confidence interval 0.87 to 1.18) in the intermediate and 1.02 (0.88 to 1.20) in the highest exposure category for all cancers (P=0.79 for trend), 0.97 (0.69 to 1.37) and 0.76 (0.51 to 1.12), respectively, for brain and central nervous system cancers (P=0.33 for trend), and 1.16 (0.90 to 1.48) and 1.03 (0.79 to 1.34) for leukaemia and non-Hodgkin's lymphoma (P=0.51 for trend). There is no association between risk of early childhood cancers and estimates of the mother's exposure to mobile phone base stations during pregnancy. This has been one of the most bizarre papers we have seen in recent months. A paper, attempting to assess the childhood cancer risk from in utero exposure from base stations, that has ignored every other relevant exposure that the mother and unborn child might have been exposed to. This includes, but is not limited to, exposures away from home, mobile phone use, mass transport, office exposure, DECT cordless phone use, WiFi, and in fact any other form of RF exposure from any source at any time, and isn't even modelled on actually exposure from the base stations included in the study. It is puzzling how this work even got funded.

This article presents the measurement results of human exposure to CDMA800 and CDMA1800 signals at locations in Korea where the general public has expressed concern. Measurements were performed at 50 locations across the country to compare the electromagnetic field levels with the general public exposure compliance limits. At each site, the distances between the nearest single or co-located base station and measurement positions were within a range of approximately 32-422 m. The measured exposure levels were very low compared with the international standard and the Korean human protection notice. The highest field level was 1.5 V/m, which corresponds to 0.15% of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines for human exposure. Another paper (such as those by Mann and Frei in the UK and Switzerland respectively) showing what typical electrical field exposures are in another country.

The question of whether exposure to extremely low frequency magnetic fields (ELF-MF), may contribute to cerebral cancer and neurodegeneration is of current interest. In this study we investigated whether exposure to ELF-MF (50 Hz-1 mT) harms cerebral DNA and induces expression of 70-kDa heat shock protein (hsp70). CD1 mice were exposed to a MF (50 Hz-1 mT) for 1 or 7 days (15 h/day) and sacrificed either at the end of exposure or after 24 h. Unexposed and sham-exposed mice were used as controls. Mouse brains were dissected into cerebral cortex-striatum, hippocampus and cerebellum to evaluate primary DNA damage and hsp70 gene expression. Food intake, weight gain, and motor activity were also evaluated. An increase in primary DNA damage was detected in all cerebral areas of the exposed mice sacrificed at the end of exposure, as compared to controls. DNA damage, as can be evaluated by the comet assay, appeared to be repaired in mice sacrificed 24 h after a 7-day exposure. Neither a short (15 h) nor long (7 days) MF-exposure induced hsp70 expression, metabolic and behavioural changes. These results indicate that in vivo ELF-MF induce reversible brain DNA damage while they do not elicit the stress response.

Evidence from epidemiological and animal studies showed that exposure to extremely low frequency magnetic fields (ELF-MF) could produce deleterious effects on reproduction. In order to investigate the possible mechanism of MF exposure on reproductive effects, first trimester human chorionic villi at 8-10 weeks' gestation were obtained, and trophoblasts were isolated, cultured, and exposed to a 50-Hz MF for different durations. The human chorionic gonadotropin (hCG) and progesterone in the culture medium was measured by electrochemiluminescence immunoassay. The mRNA levels of apoptosis-related genes bcl-2, bax, caspase-3, p53, and fas in trophoblasts were analyzed using real-time RT-PCR. The results showed that exposure of trophoblasts to MF at 0.2 mT for 72 h did not affect secretion of hCG and progesterone from these cells. There was also no significant change in secretion of these hormones when trophoblasts were exposed to a 0.4 mT MF for 48 h. However, MF significantly inhibited hCG and progesterone secretion of trophoblasts after exposure for 72 h at 0.4 mT. Results of apoptosis-related gene expression analysis showed that, within 72 h of exposure at 0.4 mT, there was no significant difference between MF exposure and control on the expression pattern of each gene. Based on results of the present experiment, it is suggested that exposure to MF for a longer duration (72 h) could inhibit secretion of hCG and progesterone by human first trimester villous trophoblasts, however, the effect might not be related to trophoblast apoptosis.

For 30 years, there have been suggestions that extremely low frequency magnetic fields such as those are produced by electric power systems may be associated with elevated risks of childhood leukemia. These suggestions are driven by epidemiological evidence, and it has been common to characterize that evidence as showing a threshold effect, with no increase in risk below a threshold, often 0.3 or 0.4 muT, and a constant risk above it. Such a threshold would, however, be biologically unlikely. We tested alternative dose-response relationships quantitatively. We obtained five exposure data sets, applied several candidate dose-response relationships to each one, and performed a regression analysis to see how well they fit each of the three epidemiological data sets. Threshold dose-response relationships performed only moderately. Linear relationships were generally even poorer. The fit was improved by adding quadratic terms or performing non-linear regression. There are limitations in our analysis, stemming from the available data, but addressing this issue in a data-based, quantitative manner should improve understanding, allow better calculations to be made of attributable numbers, and hence ultimately inform public policy making. This clearly shows that the current models (threshold or linear no-threshold) do not fit the existing data very well. Rather than continuing to fiddle around with existing data, it is time that we properly investigate other metrics like peak-level exposure and maternal exposure during pregnancy. If an association were to be seen with foetal exposure, then that could well explain the rise in childhood leukaemia during the 20th century and also why the existing post-natal epidemiology results never show a consistent picture.

Despite numerous studies, there is no definitive evidence that high-frequency electromagnetic field (EMF) exposure is a risk to human health. To the contrary, this report presents the first evidence that long-term EMF exposure directly associated with cell phone use (918 MHz; 0.25 w/kg) provides cognitive benefits. Both cognitive-protective and cognitive-enhancing effects of EMF exposure were discovered for both normal mice and transgenic mice destined to develop Alzheimer's-like cognitive impairment. The cognitive interference task utilized in this study was designed from, and measure-for-measure analogous to, a human cognitive interference task. In Alzheimer's disease mice, long-term EMF exposure reduced brain amyloid-beta (Abeta) deposition through Abeta anti-aggregation actions and increased brain temperature during exposure periods. Several inter-related mechanisms of EMF action are proposed, including increased Abeta clearance from the brains of Alzheimer's disease mice, increased neuronal activity, and increased cerebral blood flow. Although caution should be taken in extrapolating these mouse studies to humans, we conclude that EMF exposure may represent a non-invasive, non-pharmacologic therapeutic against Alzheimer's disease and an effective memory-enhancing approach in general. This paper was strongly promoted around the world media by two very misleading Press releases that both claimed that "cell-phone use" both protects against and reverses cognitive impairment in Alzheimer's disease. The paper itself does not claim this. It did find that two one-hour exposures to a 918 MHz simulated GSM handset signal at a typical human max SAR value (0.25 W/kg) improved several measures of Alzheimer's Disease in the mice. However, the exposure was to the whole-body from far-field RF and nor near-field brain only exposure that human cellphone users experience. The researchers note that the temperature of the mice increased during the exposure periods by 0.5 to 1 °C and this may have played a crucial role that affected the results. The researchers did not simulate the real ELF magnetic field pulses from the battery current flow in real GSM cellphone handset use. Overall, an interesting result and one that should be followed up but, at present, it does not directly relate to cellphone use.

The negative impact of mobile phones on sperm motility has been previously described. Both fructose and citrate are important components in semen that facilitate sperm motility. To date, no studies have investigated the effect of exposure to electromagnetic radiation emitted from the mobile phone on their levels.. Therefore, a longitudinal study using the adult rabbit as a model was undertaken. A total of 30 adult male rabbits were randomly divided into three groups. The first (phone) group was placed in specially designed cages, and exposed to radio frequency emitted from a mobile phone (900 MHz) kept in standby mode and positioned adjacent to the genitalia for 8 h daily for 12 weeks. The other two groups served as controls; the stress group which was housed in the same kind of cages to evaluate any cage-induced anxiety, and the control group which was housed in the conventional roomy cages. Semen samples were retrieved weekly. Sperm motility and viability, semen fructose and citrate, and serum testosterone were measured. Histological sections from the prostatic complex, ampulla, and vesicular gland were evaluated. A significant drop in both fructose levels (257 +/-11.6 vs. 489 +/- 8.4 mg %, the baseline level) and number of motile sperms (50 vs. 72%) was observedin the phone group at the 10th week. However, no correlation was found between the two values. The stress control animals showed a similar but significantly less decline in motility No significant changes in citrate levels or other study parameters were seen in the three animal groups throughout the study. In conclusion, the pulsed radio frequency emitted by the mobile phone kept in the standby position longitudinally affected sperm motility and fructose but not citrate levels in rabbit semen. In rabbits this time, this is yet another paper finding sperm motility effects (which would directly, and adversely, affect fertility) from mobile phone radiation - the literature for mobile phone / fertility effects continues to grow.

If mobile-phone electromagnetic fields (EMFs) are hazardous, as suggested in the literature, processes or mechanisms must exist that allow the body to detect the fields. We hypothesized that the low-frequency pulses produced by mobile phones (217 Hz) were detected by sensory transduction, as evidenced by the ability of the pulses to trigger evoked potentials (EPs). Electroencephalograms (EEGs) were recorded from six standard locations in 20 volunteers and analyzed to detect brain potentials triggered by a pulse of the type produced by mobile phones. Evoked potentials having the expected latency were found in 90% of the volunteers, as assessed using a nonlinear method of EEG analysis. Evoked potentials were not detected when the EEG was analyzed using time averaging. The possibility of systematic error was excluded by sham-exposure analyses. The results implied that mobile-phones trigger EP at the rate of 217 Hz during ordinary phone use. Chronic production of the changes in brain activity might be pertinent to the reports of health hazards among mobile-phone users. This paper involving Andy Marino (involved for decades on EMF related research with the late Robert Becker) offers some interesting insights into the possible mechanism by which some users may have adverse reactions to mobile phone use.

The interaction of mobile phone radio-frequency electromagnetic radiation (RF-EMR) with the brain is a serious concern of our society. We evaluated the effect of RF-EMR from mobile phones on passive avoidance behaviour and hippocampal morphology in rats. Healthy male albino Wistar rats were exposed to RF-EMR by giving 50 missed calls (within 1 hour) per day for 4 weeks, keeping a GSM (0.9 GHz/1.8 GHz) mobile phone in vibratory mode (no ring tone) in the cage. After the experimental period, passive avoidance behaviour and hippocampal morphology were studied. Passive avoidance behaviour was significantly affected in mobile phone RF-EMR-exposed rats demonstrated as shorter entrance latency to the dark compartment when compared to the control rats. Marked morphological changes were also observed in the CA(3) region of the hippocampus of the mobile phone-exposed rats in comparison to the control rats. Mobile phone RF-EMR exposure significantly altered the passive avoidance behaviour and hippocampal morphology in rats. In this study, GSM exposure significantly reduced the ability of the studied rats to remember conditions that they would choose to avoid. Interesting is that the exposure was created by an actual phone in silent mode.

Microwaves from mobile phones inhibited formation of 53BP1 foci in human primary fibroblasts and mesenchymal stem cells. These data parallel our previous findings for human lymphocytes. Importantly, the same GSM carrier frequency (915 MHz) and UMTS frequency band (1947.4 MHz) were effective for all cell types. Exposure at 905 MHz did not inhibit 53BP1 foci in differentiated cells, either fibroblasts or lymphocytes, whereas some effects were seen in stem cells at 905 MHz. Contrary to fibroblasts, stem cells did not adapt to chronic exposure during 2 weeks. The strongest microwave effects were always observed in stem cells. This result may suggest both significant misbalance in DSB repair and severe stress response. Our findings that stem cells are most sensitive to microwave exposure and react to more frequencies than do differentiated cells may be important for cancer risk assessment and indicate that stem cells are the most relevant cellular model for validating safe mobile communication signals.