04/04/2011 - March 2011 - Science Update

The following is a quick summary of another fifteen 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.

Results of key Soviet-era studies dealing with effects on the immune system and teratological consequences in rats exposed to radiofrequency (RF) fields serve, in part, as a basis for setting exposure limits in the USSR and the current RF standards in Russia. The World Health Organization's (WHO) International EMF Project considered these Soviet results important enough that they should be confirmed using more modern methods. Since the Soviet papers did not contain comprehensive details on how the results were obtained, Professor Yuri Grigoriev worked with Dr. Bernard Veyret to agree on the final study protocol and to conduct separate studies in Moscow and Bordeaux under the same protocol. The International Oversight Committee (IOC) provided oversight on the conduct of the studies and was the firewall committee that dealt with the sponsors and researchers. This paper gives the IOC comments and conclusions on the differing results between the two studies. In essence, the Russians and the French both agreed on an experimental protocol and conducted independent experiments. The French team found no effect, the Russian team found statistically significant effects, and this paper discusses possible reasons why this could be the case.

Low-participation rate may create selection bias, and not blinding as to case or control status may give observational bias, especially in a study with such vague definition of cut-off for exposure as Interphone.Especially worrying as to observational bias are bed-side interviews of such a mentally ill patient group with brain tumour. Patients may even have been newly operated before the interview. In fact, patients scored significantly lower than controls in the recall of words (aphasia), and in writing and drawing due to paralysis in the Danish part of Interphone. It is unclear why younger cases were excluded from the final Interphone report, especially since our results indicate highest risk in the youngest age group.5 Thus, Denmark and Sweden included the age group 20-29 years, Norway 19-29 years and UK 18-29 years, and the age groups are unclear for the countries that have not published individual results. We urge Interphone to fill in the gaps in our Tables 1 and 2, so as to make full comparison with our data possible. Currently, we have presented results on the association of use of wireless phones and malignant brain tumours among deceased cases, that were excluded from our study, using deceased controls. These results confirm our previous findings of an increased risk for malignant brain tumour among mobile phone users.

Purpose: We investigated whether one-year, long-term, simultaneous exposure to code division multiple access (CDMA; 849 MHz) and wideband code division multiple access (WCDMA; 1.95 GHz) radiofrequencies (RF) would induce chronic illness in Sprague-Dawley (SD) rats. Materials and methods: Two groups of 40 SD rats (50% males and females in sham and exposed groups) were exposed to CDMA and WCDMA RF simultaneously at 2.0 W/kg for 45 min/day (total 4.0 W/kg), 5 days per week for a total of one year. Body and organ weight measurements, urinalysis, haematological and blood biochemical analysis, and histopathological evaluations were performed. Results: The mortality patterns in male and female rats exposed to RF were compared with those found in gender-matched sham control animals. No significant alteration in body weight was observed with the simultaneous combined RF exposure. Most RF-exposed rats showed no significant alteration, based on urinalysis, haematology, blood biochemistry, or histopathology. However, some altered parameters of the complete blood count and serum chemistry were seen in RF-exposed rats. The total tumour incidence was not different between sham-exposed and RF-exposed animals. Conclusions: Our results suggest that one-year chronic exposure to CDMA (849 MHz) and WCDMA (1.95 GHz) RF simultaneously at 2.0 W/kg for 45-min RF exposure periods (total, 4 W/kg) did not increase chronic illness in rats, although there were some altered parameters in the complete blood count and serum chemistry.

Electromagnetic fields (EMF) have been shown to exert beneficial effects on cartilage tissue. Nowadays, differentiated human mesenchymal stem cells (hMSCs) are discussed as an alternative approach for cartilage repair. Therefore, the aim of this study was to examine the impact of EMF on hMSCs during chondrogenic differentiation. HMSCs at cell passages five and six were differentiated in pellet cultures in vitro under the addition of human fibroblast growth factor 2 (FGF-2) and human transforming growth factor-Beta(3) (TGF-Beta(3)). Cultures were exposed to homogeneous sinusoidal extremely low-frequency magnetic fields (5 mT) produced by a solenoid or were kept in a control system. After 3 weeks of culture, chondrogenesis was assessed by toluidine blue and safranin-O staining, immunohistochemistry, quantitative real-time polymerase chain reaction (PCR) for cartilage-specific proteins, and a DMMB dye-binding assay for glycosaminoglycans. Under EMF, hMSCs showed a significant increase in collagen type II expression at passage 6. Aggrecan and SOX9 expression did not change significantly after EMF exposure. Collagen type X expression decreased under electromagnetic stimulation. Pellet cultures at passage 5 that had been treated with EMF provided a higher glycosaminoglycan (GAG)/DNA content than cultures that had not been exposed to EMF. Chondrogenic differentiation of hMSCs may be improved by EMF regarding collagen type II expression and GAG content of cultures. EMF might be a way to stimulate and maintain chondrogenesis of hMSCs and, therefore, provide a new step in regenerative medicine regarding tissue engineering of cartilage. Another paper demonstrating the healing potential of relatively high ELF EMF exposure (about 4-5 orders of magnitude higher than typical daily human exposure).

This study investigates occupational exposure to electromagnetic fields in front of a multi-band base station antenna for mobile communications at 900, 1800, and 2100 MHz. Finite-difference time-domain method was used to first validate the antenna model against measurement results published in the literature and then investigate the specific absorption rate (SAR) in two heterogeneous, anatomically correct human models (Virtual Family male and female) at distances from 10 to 1000 mm. Special attention was given to simultaneous exposure to fields of three different frequencies, their interaction and the additivity of SAR resulting from each frequency. The results show that the highest frequency-2100 MHz-results in the highest spatial-peak SAR averaged over 10 g of tissue, while the whole-body SAR is similar at all three frequencies. At distances >200 mm from the antenna, the whole-body SAR is a more limiting factor for compliance to exposure guidelines, while at shorter distances the spatial-peak SAR may be more limiting. For the evaluation of combined exposure, a simple summation of spatial-peak SAR maxima at each frequency gives a good estimation for combined exposure, which was also found to depend on the distribution of transmitting power between the different frequency bands.

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. Proliferative rates and neuritogenesis were tested by colorimetric assay and morphological analysis, respectively; reactive oxygen species (ROS) levels and intracellular Ca(2+) variations monitored using single cell videomicroscopy. 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 Ca(2+) variations in undifferentiated cells, in which basal intracellular Ca(2+) resulted increased after chronic exposure. In addition acute exposure affected cell response to a depolarizing agent, while basal membrane potential was not changed. Even if further studies remain necessary to identify the ROS/intracellular Ca(2+)cross-talking pathway activated by ELF-EMF exposure, we support the hypothesis that ROS and Ca(2+) could be the cellular "primum movens" of the ELF-EMF induced effects on biological systems.

A differential survival time based on SES is a particular problem for this study because of its relationship to cellphone uptake and use. Specifically, cellphone plans are more likely to be taken out by those who can afford them: minutes cost money, and those with more social resources are also more likely to be employed and to use their phones for work. The problem with this is that it introduces bias into the sample in a way that is not considered in the study, and that would bias them that is explicated in Morgan's response paper. Specifically, we would expect that those who use their cellphones more and for longer periods of time would be protected from brain tumours and mortality, a result that is evident from the results presented: those using phones regularly (5-114.9 and 115-359.9 h) are significantly less likely to have meningioma [odds ratio (OR) 0.67-0.74] or to have glioma (OR 0.71-0.82). However, perhaps more frustrating for their results, those in the extreme use groups seem to have significantly higher odds of both cancers, a result that will have been suppressed by SES. Thus, while the study was clearly well designed and the authors completed an interesting and thorough study, I am concerned that these results may be tempered, by the dual relationship of SES to cellphone use and to glioma and meningioma in a way that may detract from, or even reverse, the authors' claims.

The Interphone Study on brain cancer rests upon a case-control design with recall of past exposures recorded with substantial inaccuracy and low participation rates. This commentary questions the wisdom in choosing this design and argues that funding could and should have been used better by setting up a large-scale cohort study that could address other potential endpoints besides cancer.

Exposures to electric and magnetic fields are among the most ubiquitous exposures that the Canadian population experiences. Sources of electric and magnetic field exposures may be occupational or residential and include proximity to certain types of electrical equipment, transmission and distribution power lines as well as appliance use. The early studies of children tended toward a consistent association between risks for leukemia and brain cancer and residential proximity to power lines having high wire configuration. More recent studies-and studies which have attempted to improve upon the measurement of exposure by using calculated fields, point-in-time or personal monitoring-have been inconsistent, with some suggesting increased risk and others not. Occupational exposures have suggested an increase in risk for leukemia, and to a lesser extent brain cancer and Non-Hodgkin lymphoma. However, studies of residential exposures and cancer in adults generally have suggested no effect. Laboratory work has been unable to demonstrate a biological mechanism which might explain the epidemiological findings. In spite of extensive efforts over the past 20 years and many expert reviews, it has been difficult to reach consensus regarding the carcinogenic effects of electric and magnetic fields. Exposure assessment has proven to be complex, and agreement on the relevant exposure metric has not yet been obtained. There is justification to question whether point-in-time measures in homes are appropriate indices of the relevant etiological exposure, as they fail to account for changes over time, peak exposures or time-varying fields. Nevertheless, it is probably desirable to err on the side of caution in not placing too much weight on the inconsistencies. The IARC has classified EMF as a "possible carcinogen" which refers to the circumstances where there is limited evidence of carcinogenicity in humans and inadequate evidence in experimental animals. The IARC review indicated limited evidence for the carcinogenicity of extremely low-frequency magnetic fields in relation to childhood leukemia at high level exposure in the residential environment (average residential magnetic field strength > 0.4 µT). Even higher levels of exposure in the occupational environment may increase the risk of leukemia in adults.

Basic restrictions for protecting against localized tissue heating induced from exposure to radiofrequency (RF) fields are typically specified as the specific energy absorption rate (SAR), which is mass averaged in recognition of the thermal diffusion properties of tissues. This article seeks to determine the most appropriate averaging mass (1, 3, 5, 7, or 10 g) and averaging shape (cube or sphere). We also consider an alternative metric, volumetric energy absorption rate (VAR), which uses volume averaging (over 1, 3, 5, 7, and 10 cm(3); cube and sphere). The SAR and VAR averaging approaches were compared by considering which was a better predictor of tissue temperature rise (deltaT) induced by near- and far-field RF exposures (0.5-6 GHz), calculated in a detailed human body model. For the exposure scenarios that we examined, VAR is better correlated with deltaT than SAR, though not at a statistically significant level for most of the metric types we studied. However, as VAR offers substantive advantages in ease of assessment we recommend this metric over SAR. Averaging over a cube or a sphere provides equivalent levels of correlation with deltaT, and so we recommend choosing the averaging shape on the basis of which is easier to assess. The optimal averaging volume is 10 cm(3) for VAR, and the optimal mass is 10 g for SAR. The correlation between VAR or SAR and deltaT diminishes substantially at 6 GHz, where incident power flux density may be a better exposure metric.

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 B(dc)=3µT to a highly controlled and standardized ELF-EMF signal (20-5000Hz, B(ac)=5µT, 30min) and cytokine production was measured at different time points after stimulation. No significant difference in immune response, as reflected by IL-1Beta, IL-6, TNFAlpha, 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.

The present study investigates the effect of free radical formation due to mobile phone exposure and effect on fertility pattern in 70-day-old male Wistar rats (sham exposed and exposed). Exposure took place in Plexiglas cages for 2 h a day for 35 days to mobile phone frequency. The specific absorption rate was estimated to be 0.9 W/kg. An analysis of antioxidant enzymes glutathione peroxidase (P < 0.001) and superoxide dismutase (P < 0.007) showed a decrease, while an increase in catalase (P < 0.005) was observed. Malondialdehyde (P < 0.003) showed an increase and histone kinase (P = 0.006) showed a significant decrease in the exposed group. Micronuclei also show a significant decrease (P < 0.002) in the exposed group. A significant change in sperm cell cycle of G(0)-G(1) (P = 0.042) and G(2)/M (P = 0.022) were recorded. Generation of free radicals was recorded to be significantly increased (P = 0.035). Our findings on antioxidant, malondialdehyde, histone kinase, micronuclei, and sperm cell cycle are clear indications of an infertility pattern, initiated due to an overproduction of reactive oxygen species. It is concluded that radiofrequency electromagnetic wave from commercially available cell phones might affect the fertilizing potential of spermatozoa.

The accumulating effects of exposure to electromagnetic radiation emitted by a conventional mobile phone (standby position) on the testicular function and structure are not yet fully investigated. To study these effects longitudinally, a total of 24 adult male rabbits were randomly and equally divided into three groups. Rabbits in the first (phone) group were exposed, in specially designed cages, to radio frequency emitted from the mobile phone (800 MHz) in a standby position opposite to that of testes for 8 h daily for 12 weeks. The second group consisted of the stress controls which were kept in the same kind of cages to appreciate any cage-induced anxiety. The third group included the ordinary controls which were kept in the conventional roomy cages. Semen analysis and sperm function tests (viability, hypo-osmotic swelling and acridine orange) were conducted weekly. Histological testicular sections and serum total testosterone were also evaluated. A drop in the sperm concentration appeared in the phone group at week 6. This became statistically significant at week 8, compared with the two control (stress and ordinary) groups (133, 339 and 356 x 106/mL, respectively) and to the initial sperm count (341 x 106/mL) of this group. Motile sperm population showed similarity amongst the three study groups until week 10 when it declined significantly, and thereafter in the phone and stress control groups, with more significant decline in the phone animals (50, 61 and 72.4%, respectively). Histological examination showed also a significant decrease in the diameter of seminiferous tubules in the phone group vs. the stress and ordinary controls (191 microm vs. 206 and 226 microm, respectively). The other study points did not show any difference. In conclusion, low intensity pulsed radio frequency emitted by a conventional mobile phone kept in the standby position could affect the testicular function and structure in the adult rabbit. Although yet another paper on fertility highlighting a positive effect, it appears that many areas of this research are questionable. 800 MHz is not the frequency of GSM signals (including in Japan, where the research was carried out), and having the phones in standby mode will not give anywhere near the amount of exposure claimed in the study. Furthermore, the results, showing absolutely no effect for 8 weeks then a very drastic change for the last 4 seem particularly implausible.

Effects of a 50 Hz extra-low frequency electromagnetic field (ELF EMF) on in vitro rabbit spermatozoa motility were analyzed, as well as the effect on fertilization rates after insemination. Pooled semen samples and a control were exposed to 50 Hz ELF EMF. The difference of the samples of the test groups G1 and G2 with the control group CG (75.56%) for spermatozoa motility were found to be significant (P < 0.01). Differences were significant (P < 0.01) for curvilinear velocity (VCL) between the test group G3 (122.38 microm/s) and the control group CG (112.02 microm/s). Hormonally stimulated adult (9-12 months) females (n = 140) were inseminated with semen samples from G1, G2, G3 and CG (0.88 x 109 spermatozoa/0.5 mL average insemination portion) immediately after ELF EMF exposure and fertilization (kindling) rates were calculated. For the G2 it was 54.28% data indicate 50 Hz ELF EMF induced alterations of spermatozoa motility and kindling rate in rabbits, therefore influencing fertility.

A double blind study on BALB/c mice was conducted to examine the effects of extremely low-frequency electromagnetic fields on fertility. The mice were continuously exposed or sham-exposed from conception for two generations to magnetic fields varying between 0.5 and 77 muT. Biological parameters related to fertility were evaluated. Serum testosterone levels and mass of testes and adrenals were determined. No significant difference was found between the sham-exposed and exposed groups for all the biological endpoints, except for sperm motility. A significant difference between the two groups was found prior to the swim-up test with quantitative analysis of sperm motility as well as after the swim-up test for quantitative and qualitative analysis of sperm motility. ELF-EMFs significantly decreased the number of living sperm and the quality of movement of sperm, although these adversities did not impact on the outcome of the other parameters investigated.