International and national expert group evaluations: biological/health effects of radiofrequency fields

Ion channels as molecular targets of glioblastoma electrotherapy

Therapies with weak, non-ionizing electromagnetic fields comprise FDA-approved treatments such as Tumor Treating Fields (TTFields) that are used for adjuvant therapy of glioblastoma. In vitro data and animal models suggest a variety of biological TTFields effects. In particular, effects ranging from direct tumoricidal, radio- or chemotherapy-sensitizing, metastatic spread-inhibiting, up to immunostimulation have been described. Diverse underlying molecular mechanisms, such as dielectrophoresis of cellular compounds during cytokinesis, disturbing the formation of the spindle apparatus during mitosis, and perforating the plasma membrane have been proposed. Little attention, however, has been paid to molecular structures that are predestinated to percept electromagnetic fields-the voltage sensors of voltage-gated ion channels. The present review article briefly summarizes the mode of action of voltage sensing by ion channels. Moreover, it introduces into the perception of ultra-weak electric fields by specific organs of fishes with voltage-gated ion channels as key functional units therein. Finally, this article provides an overview of the published data on modulation of ion channel function by diverse external electromagnetic field protocols. Combined, these data strongly point to a function of voltage-gated ion channels as transducers between electricity and biology and, hence, to voltage-gated ion channels as primary targets of electrotherapy.

Adverse effects of 900, 1800 and 2100 MHz radiofrequency radiation emitted from mobile phones on bone and skeletal muscle

The goal of this study was to biomechanically and morphologically research both the impact of mobile phone like radiofrequency radiations (RFR) on the tibia and the effects on skeletal muscle through oxidative stress parameters. Fifty-six rats (200-250 g) were put into groups: healthy sham (n = 7), healthy RFR (900, 1800, 2100 MHz) (n = 21), diabetic sham (n = 7) and diabetic RFR (900, 1800, 2100 MHz) (n = 21). Over a month, each group spent two hours/day in a Plexiglas carousel. The rats in the experimental group were exposed to RFR, but the sham groups were not. At the end of the experiment, the right tibia bones and skeletal muscle tissue were removed. The three-point bending test and radiological evaluations were performed on the bones, and CAT, GSH, MDA, and IMA in muscles were measured. There were differences in biomechanics properties and radiological evaluations between the groups (p < .05). In the measurements in the muscle tissues, significant differences were statistically found (p < .05). The average whole-body SAR values for GSM 900, 1800 and 2100 MHz were 0.026, 0.164, and 0.173 W/kg. RFRs emitted from mobile phone may cause adverse effects on tibia and skeletal muscle health, though further studies are needed.

Cellular Telephone Use and the Risk of Brain Tumors: Update of the UK Million Women Study

BACKGROUND

The ongoing debate of whether use of cellular telephones increases the risk of developing a brain tumor was recently fueled by the launch of the fifth generation of wireless technologies. Here, we update follow-up of a large-scale prospective study on the association between cellular telephone use and brain tumors.

METHODS

During 1996-2001, 1.3 million women born in 1935-1950 were recruited into the study. Questions on cellular telephone use were first asked in median year 2001 and again in median year 2011. All study participants were followed via record linkage to National Health Services databases on deaths and cancer registrations (including nonmalignant brain tumors).

RESULTS

During 14 years follow-up of 776 156 women who completed the 2001 questionnaire, a total of 3268 incident brain tumors were registered. Adjusted relative risks for ever vs never cellular telephone use were 0.97 (95% confidence interval = 0.90 to 1.04) for all brain tumors, 0.89 (95% confidence interval = 0.80 to 0.99) for glioma, and not statistically significantly different to 1.0 for meningioma, pituitary tumors, and acoustic neuroma. Compared with never-users, no statistically significant associations were found, overall or by tumor subtype, for daily cellular telephone use or for having used cellular telephones for at least 10 years. Taking use in 2011 as baseline, there were no statistically significant associations with talking for at least 20 minutes per week or with at least 10 years use. For gliomas occurring in the temporal and parietal lobes, the parts of the brain most likely to be exposed to radiofrequency electromagnetic fields from cellular telephones, relative risks were slightly below 1.0.

CONCLUSION

Our findings support the accumulating evidence that cellular telephone use under usual conditions does not increase brain tumor incidence.

Recommendations and quality criteria for micronucleus studies with humans

Micronucleus (MN) analyses in peripheral blood lymphocytes and exfoliated cells from different organs (mouth, nose, bladder and cervix) are at present the most widely used approaches to detect damage of genetic material in humans. MN are extranuclear DNA-containing bodies, which can be identified microscopically. They reflect structural and numerical chromosomal aberrations and are formed as a consequence of exposure to occupational, environmental and lifestyle genotoxins. They are also induced as a consequence of inadequate intake of certain trace elements and vitamins. High MN rates are associated with increased risk of cancer and a range of non-cancer diseases in humans. Furthermore, evidence is accumulating that measurements of MN could be a useful tool for the diagnosis and prognosis of different forms of cancer and other diseases (inflammation, infections, metabolic disorders) and for the assessment of the therapeutic success of medical treatments. Recent reviews of the current state of knowledge suggest that many clinical studies have methodological shortcomings. This could lead to controversial findings and limits their usefulness in defining the impact of exposure concentrations of hazardous chemicals, for the judgment of remediation strategies, for the diagnosis of diseases and for the identification of protective or harmful dietary constituents. This article describes important quality criteria for human MN studies and contains recommendations for acceptable study designs. Important parameters that need more attention include sufficiently large group sizes, adequate duration of intervention studies, the exclusion of confounding factors which may affect the results (sex, age, body mass index, nutrition, etc.), the evaluation of appropriate cell numbers per sample according to established scoring criteria as well as the use of proper stains and adequate statistical analyses.

Methodology of Studying Effects of Mobile Phone Radiation on Organisms: Technical Aspects

The negative influence of non-ionizing electromagnetic radiation on organisms, including humans, has been discussed widely in recent years. This paper deals with the methodology of examining possible harmful effects of mobile phone radiation, focusing on in vivo and in vitro laboratory methods of investigation and evaluation and their main problems and difficulties. Basic experimental parameters are summarized and discussed, and recent large studies are also mentioned. For the laboratory experiments, accurate setting and description of dosimetry are essential; therefore, we give recommendations for the technical parameters of the experiments, especially for a well-defined source of radiation by Software Defined Radio.

Brain Tumor Causes, Symptoms, Diagnosis and Radiotherapy Treatment

The strategy used for the treatment of given brain cancer is critical in determining the post effects and survival. An oncological diagnosis of tumor evaluates a range of parameters such as shape, size, volume, location and neurological complexity that define the symptomatic severity. The evaluation determines a suitable treatment approach chosen from a range of options such as surgery, chemotherapy, hormone therapy, radiation therapy and other targeted therapies. Often, a combination of such therapies is applied to achieve superior results. Radiotherapy serves as a better treatment strategy because of a higher survival rate. It offers the flexibility of synergy with other treatment strategies and fewer side effects on organs at risk. This review presents a radiobiological perspective in the treatment of brain tumor. The cause, symptoms, diagnosis, treatment, post-treatment effects and the framework involved in its elimination are summarized.

Genotoxicity of radiofrequency electromagnetic fields: Protocol for a systematic review of in vitro studies

BACKGROUND

Exposure to radiofrequency electromagnetic fields (RF-EMF, 100 kHz - 300 GHz) emitted by wireless communication technologies is pervasive and ubiquitous. Concern has been raised about possible adverse effects to human health. In 2011 the International Agency for Research on Cancer has classified RF-EMF as possibly carcinogenic to humans, highlighting that the evidence is weak and far from conclusive. Updated systematic reviews of the scientific literature on this topic are lacking, especially for mechanistic studies.

OBJECTIVES

To develop a protocol for a systematic review of experimental studies investigating genotoxic effects induced by RF-EMF in in vitro cellular models. Genotoxicity is one of the key-biological indicators of carcinogenicity, and the most common characteristics of established carcinogens. The predefined procedures for conducting the systematic review are outlined below.

METHODS

We will follow the guidelines developed by the National Toxicology Program-Office of Health Assessment and Translation (NTP-OHAT), adapted to the evaluation of in vitro studies.

ELIGIBILITY CRITERIA

We will include experimental in vitro studies addressing the relationship between controlled exposures to RF-EMF and genotoxicity in mammalian cells only. Eligibility for inclusion will be further restricted to peer reviewed articles reporting findings from primary studies.

INFORMATION SOURCES

We will search the scientific literature databases NCBI PubMed, Web of Science, and EMF-Portal. No filter on publication date will be applied. Only studies published in English will be considered. The reference lists of the included papers and available reviews will be screened for unidentified relevant papers. References will be managed through Endnote X9 software.

DATA EXTRACTION AND SYNTHESIS OF RESULTS

Data from included papers will be extracted according to predefined forms. Heterogeneity within the available evidence will determine the type of evidence synthesis that is appropriate. Findings will be summarized in tables, graphical displays and in a narrative synthesis of the available evidences. A meta-analysis will be carried out if subgroups of studies homogeneous in terms of exposure characteristics, endpoint, and cell types will be identified.

RISK OF BIAS

The internal validity of included studies will be assessed using the NTP-OHAT Risk of Bias Rating Tool for animal studies, adapted to in vitro studies. This stage of the process will be managed through the Health Assessment Workspace Collaborative (HAWC).

EVIDENCE APPRAISAL

To rate confidence in the body of evidence, we will use the OHAT GRADE-based approach for animal studies.

FRAMEWORK AND FUNDING

This protocol concerns one of the evidence streams considered in a larger systematic review of the scientific literature on the potential carcinogenicity of RF-EMF, performed by scientists from several Italian public research agencies. The project is supported by the Italian Workers' Compensation Authority (INAIL) in the framework of the CRA with the Istituto Superiore di Sanità "BRiC 2018/06 - Scientific evidence on the carcinogenicity of radiofrequency electromagnetic fields".

Estimated whole-brain and lobe-specific radiofrequency electromagnetic fields doses and brain volumes in preadolescents

OBJECTIVE

To assess the association between estimated whole-brain and lobe-specific radiofrequency electromagnetic fields (RF-EMF) doses, using an improved integrated RF-EMF exposure model, and brain volumes in preadolescents at 9-12 years old.

METHODS

Cross-sectional analysis in preadolescents aged 9-12 years from the Generation R Study, a population-based birth cohort set up in Rotterdam, The Netherlands (n = 2592). An integrated exposure model was used to estimate whole-brain and lobe-specific RF-EMF doses (mJ/kg/day) from different RF-EMF sources including mobile and Digital Enhanced Cordless Telecommunications (DECT) phone calls, other mobile phone uses than calling, tablet use, laptop use, and far-field sources. Whole-brain and lobe-specific RF-EMF doses were estimated for all RF-EMF sources together (i.e. overall) and for three groups of RF-EMF sources that lead to a different pattern of RF-EMF exposure. Information on brain volumes was extracted from magnetic resonance imaging scans.

RESULTS

Estimated overall whole-brain RF-EMF dose was 84.3 mJ/kg/day. The highest overall lobe-specific dose was estimated in the temporal lobe (307.1 mJ/kg/day). Whole-brain and lobe-specific RF-EMF doses from all RF-EMF sources together, from mobile and DECT phone calls, and from far-field sources were not associated with global, cortical, or subcortical brain volumes. However, a higher whole-brain RF-EMF dose from mobile phone use for internet browsing, e-mailing, and text messaging, tablet use, and laptop use while wirelessly connected to the internet was associated with a smaller caudate volume.

CONCLUSIONS

Our results suggest that estimated whole-brain and lobe-specific RF-EMF doses were not related to brain volumes in preadolescents at 9-12 years old. Screen activities with mobile communication devices while wirelessly connected to the internet lead to low RF-EMF dose to the brain and our observed association may thus rather reflect effects of social or individual factors related to these specific uses of mobile communication devices. However, we cannot discard residual confounding, chance finding, or reverse causality. Further studies on mobile communication devices and their potential negative associations with brain development are warranted, regardless whether associations are due to RF-EMF exposure or to other factors related to their use.

Radiation protection in non-ionizing and ionizing body composition assessment procedures

Body composition assessment (BCA) represents a valid instrument to evaluate nutritional status through the quantification of lean and fat tissue, in healthy subjects and sick patients. According to the clinical indication, body composition (BC) can be assessed by different modalities. To better analyze radiation risks for patients involved, BCA procedures can be divided into two main groups: the first based on the use of ionizing radiation (IR), involving dual energy X-ray absorptiometry (DXA) and computed tomography (CT), and others based on non-ionizing radiation (NIR) [magnetic resonance imaging (MRI)]. Ultrasound (US) techniques using mechanical waves represent a separate group. The purpose of our study was to analyze publications about IR and NIR effects in order to make physicians aware about the risks for patients undergoing medical procedures to assess BCA providing to guide them towards choosing the most suitable method. To this end we reported the biological effects of IR and NIR and their associated risks, with a special regard to the excess risk of death from radio-induced cancer. Furthermore, we reported and compared doses obtained from different IR techniques, giving practical indications on the optimization process. We also summarized current recommendations and limits for techniques employing NIR and US. The authors conclude that IR imaging procedures carry relatively small individual risks that are usually justified by the medical need of patients, especially when the optimization principle is applied. As regards NIR imaging procedures, a few studies have been conducted on interactions between electromagnetic fields involved in MR exam and biological tissue. To date, no clear link exists between MRI or associated magnetic and pulsed radio frequency (RF) fields and subsequent health risks, whereas acute effects such as tissue burns and phosphenes are well-known; as regards the DNA damage and the capability of NIR to break chemical bonds, they are not yet robustly demonstrated. MRI is thus considered to be very safe for BCA as well US procedures.

Wi-Fi (2.4 GHz) affects anti-oxidant capacity, DNA repair genes expression and, apoptosis in pregnant mouse placenta

OBJECTIVES

The placenta provides nutrients and oxygen to embryo and removes waste products from embryo's blood. As far as we know, the effects of exposure to Wi-Fi (2.4 GHz) signals on placenta have not been evaluated. Hence, we examined the effect of prenatal exposure to Wi-Fi signals on anti-oxidant capacity, expressions of CDKNA1, and GADD45a as well as apoptosis in placenta and pregnancy outcome.

MATERIALS AND METHODS

Pregnant mice were exposed to Wi-Fi signal (2.4 GHz) for 2 and 4 hr. Placenta tissues were examined to measure the MDA and SOD levels. To measure SOD, CDKNA1, GADD45a, Bax, and Bcl-2 expressions were compared by real-time PCR analysis. TUNEL assay was used to assess apoptosis in placenta tissues. The results were analyzed by one-way analysis of variance (ANOVA) using Prism version 6.0 software.

RESULTS

MDA and SOD levels had significantly increased in exposed Wi-Fi signal groups (P-value< 0.05). Also, quantitative PCR experiment showed that SOD mRNA expression significantly increased in Wi-Fi signal groups. The data showed that CDKN1A and GADD45a genes were increased in Wi-Fi groups (P-value<0.05). The quantitative PCR and the TUNEL assay showed that apoptosis increased in Wi-Fi groups (P-value<0.05).

CONCLUSION

Our results provide evidence that Wi-Fi signals increase lipid peroxidation, SOD activity (oxidative stres), apoptosis and CDKN1A and GADD45a overexpression in mice placenta tissue. However, further experimental studies are warranted to investigate other genes and aspects of pregnancy to determine the role of Wi-Fi radiation on fertility and pregnancy.

Appraisal of immediate and late effects of mobile phone radiations at 2100 MHz on mitotic activity and DNA integrity in root meristems of Allium cepa

The present study evaluated the potential of 2100 MHz radiofrequency radiations to act as cytotoxic and genotoxic agent. Fresh onion (Allium cepa L.) roots were exposed to electromagnetic field radiations (EMF-r) for different durations (1 h and 4 h) and evaluated for mitotic index (MI), phase index, chromosomal aberrations, and DNA damage. DNA damage was investigated with the help of the comet assay by assessing various parameters like % head DNA (HDNA), % tail DNA (TDNA), tail moment (TM), and olive tail moment (OTM). Effects of EMF-r exposure were also compared with that of methyl methanesulfonate (MMS; 90 μM), which acted as a positive control. The post-exposure effects of EMF-r after providing the test plants with an acclimatization period of 24 h were also evaluated. Compared to the control, a significant increase in the MI and aberration percentage was recorded upon 4 h of exposure. However, no specific trend of phase index in response to exposure was detected. EMF-r exposure incited DNA damage with a significant decrease in HDNA accompanied by an increase in TDNA upon exposure of 4 h. However, TM and OTM did not change significantly upon exposure as compared to that of control. Analysis of the post-exposure effects of EMF-r did not show any significant change/recovery. Our data, thus, suggest the potential cytotoxic and genotoxic nature of 2100 MHz EMF-r. Our study bears great significance in view of the swiftly emergent EMF-r in the surrounding environment and their potential for inciting aberrations at the chromosomal level, thus posing a genetic hazard.

Comprehensive Review of Quality of Publications and Meta-analysis of Genetic Damage in Mammalian Cells Exposed to Non-Ionizing Radiofrequency Fields

There have been numerous published studies reporting on the extent of genetic damage observed in animal and human cells exposed in vitro and in vivo to non-ionizing radiofrequency fields (RF, electromagnetic waves that carry energy as they propagate in air and dense media). Overall, the data are inconsistent; while some studies have suggested significantly increased damage in cells exposed to RF energy compared to unexposed and/or sham-exposed control cells, others have not. Several variables in exposure conditions used in the experiments might have contributed to the controversy. In this comprehensive review, four specific quality control measures were used to determine the quality of 225 published studies in animal and human cells exposed in vitro and in vivo to RF energy, and the results from 2,160 tests with different sample sizes were analyzed. The four specific quality control measures were as follows: 1. "Blind" collection/analysis of the data to eliminate individual/observer "bias"; 2. Adequate description of "dosimetry" for independent replication/confirmation; 3. Inclusion of "positive controls" to confirm the outcomes; and 4. Inclusion of "sham-exposed controls" which are more appropriate to compare the data with those in RF exposure conditions. In addition, meta-analysis of the genetic damage in cells exposed to RF energy and control cells, thus far available in the RF literature database, was performed to obtain the "d" values, i.e., standardized mean difference between these two types of cells or the effect size. The relationship between d values and the above-mentioned quality control measures was ascertained. In addition, the correlation between the quality control measures and the conclusions reported in the publications (no significant difference between the cells exposed to RF energy and control cells; increased damage in former cells compared to the latter; increased, no significant difference and decreased damage in cells exposed to RF energy in the same experiment; or decreased damage in cells exposed to RF energy) was examined. The overall conclusions were as follows: 1. When all four quality control measures were mentioned in the publication, the d values were smaller compared to those when one or more quality control measures were not mentioned in the investigation; 2. Based on the inclusion of quality control measures, the weighted outcome in cells exposed to RF energy (d values) indicated a very small effect, if any; 3. The number of published studies reporting no significant difference in genetic damage of cells exposed to RF energy, compared to that of control cells, increased with increased number of quality control measures employed in investigations; 4. The number of published studies reporting increased genetic damage in cells exposed to RF energy decreased with increased number of quality control measures; and 5. There was a "bias" towards the publications reporting increased genetic damage in cells exposed to RF energy even with very small sample size. Overall, the results from this study underscore the importance of including quality control measures in investigations so that the resulting data are useful, nationally and internationally, in evaluating "potential" health risks from exposure to RF energy.

Mobile phone specific electromagnetic fields induce transient DNA damage and nucleotide excision repair in serum-deprived human glioblastoma cells

Some epidemiological studies indicate that the use of mobile phones causes cancer in humans (in particular glioblastomas). It is known that DNA damage plays a key role in malignant transformation; therefore, we investigated the impact of the UMTS signal which is widely used in mobile telecommunications, on DNA stability in ten different human cell lines (six brain derived cell lines, lymphocytes, fibroblasts, liver and buccal tissue derived cells) under conditions relevant for users (SAR 0.25 to 1.00 W/kg). We found no evidence for induction of damage in single cell gel electrophoresis assays when the cells were cultivated with serum. However, clear positive effects were seen in a p53 proficient glioblastoma line (U87) when the cells were grown under serum free conditions, while no effects were found in p53 deficient glioblastoma cells (U251). Further experiments showed that the damage disappears rapidly in U87 and that exposure induced nucleotide excision repair (NER) and does not cause double strand breaks (DSBs). The observation of NER induction is supported by results of a proteome analysis indicating that several proteins involved in NER are up-regulated after exposure to UMTS; additionally, we found limited evidence for the activation of the γ-interferon pathway. The present findings show that the signal causes transient genetic instability in glioma derived cells and activates cellular defense systems.

Radiofrequency Exposure Amongst Employees of Mobile Network Operators and Broadcasters

Little is known about personal exposure to radiofrequency (RF) fields amongst employees in the telecommunications industry responsible for installing and maintaining transmitters. IARC classified RF exposure as a possible carcinogen, although evidence from occupational studies was judged to be inadequate. Hence, there is a need for improved evidence of any potentially adverse health effects amongst the workforce occupationally exposed to RF radiation. In this study, results are presented from an exposure survey using data from personal monitors used by employees in the broadcasting and telecommunication industries of the UK. These data were supplemented by spot measurements using broadband survey metres and information on daily work activities provided by employee questionnaires. The sets of real-time personal data were categorised by four types of site determined by the highest powered antenna present (high, medium or low power and ground-level sites). For measurements gathered at each type of site, the root mean square and a series of box plots were produced. Results from the daily activities diaries suggested that riggers working for radio and television broadcasters were exposed to much longer periods as compared to colleagues working for mobile operators. Combining the results from the measurements and daily activity diaries clearly demonstrate that exposures were highest for riggers working for broadcasting sites. This study demonstrates that it is feasible to carry out exposure surveys within these populations that will provide reliable estimates of exposure that can be used for epidemiological studies of occupational groups exposed to RF fields.

A short-term extremely low frequency electromagnetic field exposure increases circulating leukocyte numbers and affects HPA-axis signaling in mice

There is still uncertainty whether extremely low frequency electromagnetic fields (ELF‐EMF) can induce health effects like immunomodulation. Despite evidence obtained in vitro, an unambiguous association has not yet been established in vivo. Here, mice were exposed to ELF‐EMF for 1, 4, and 24 h/day in a short‐term (1 week) and long‐term (15 weeks) set‐up to investigate whole body effects on the level of stress regulation and immune response. ELF‐EMF signal contained multiple frequencies (20–5000 Hz) and a magnetic flux density of 10 μT. After exposure, blood was analyzed for leukocyte numbers (short‐term and long‐term) and adrenocorticotropic hormone concentration (short‐term only). Furthermore, in the short‐term experiment, stress‐related parameters, corticotropin‐releasing hormone, proopiomelanocortin (POMC) and CYP11A1 gene‐expression, respectively, were determined in the hypothalamic paraventricular nucleus, pituitary, and adrenal glands. In the short‐term but not long‐term experiment, leukocyte counts were significantly higher in the 24 h‐exposed group compared with controls, mainly represented by increased neutrophils and CD4 ± lymphocytes. POMC expression and plasma adrenocorticotropic hormone were significantly lower compared with unexposed control mice. In conclusion, short‐term ELF‐EMF exposure may affect hypothalamic‐pituitary‐adrenal axis activation in mice. Changes in stress hormone release may explain changes in circulating leukocyte numbers and composition. Bioelectromagnetics. 37:433–443, 2016. © 2016 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.

Quality Matters: Systematic Analysis of Endpoints Related to "Cellular Life" in Vitro Data of Radiofrequency Electromagnetic Field Exposure

Possible hazardous effects of radiofrequency electromagnetic fields (RF-EMF) at low exposure levels are controversially discussed due to inconsistent study findings. Therefore, the main focus of the present study is to detect if any statistical association exists between RF-EMF and cellular responses, considering cell proliferation and apoptosis endpoints separately and with both combined as a group of “cellular life” to increase the statistical power of the analysis. We searched for publications regarding RF-EMF in vitro studies in the PubMed database for the period 1995–2014 and extracted the data to the relevant parameters, such as cell culture type, frequency, exposure duration, SAR, and five exposure-related quality criteria. These parameters were used for an association study with the experimental outcome in terms of the defined endpoints. We identified 104 published articles, from which 483 different experiments were extracted and analyzed. Cellular responses after exposure to RF-EMF were significantly associated to cell lines rather than to primary cells. No other experimental parameter was significantly associated with cellular responses. A highly significant negative association with exposure condition-quality and cellular responses was detected, showing that the more the quality criteria requirements were satisfied, the smaller the number of detected cellular responses. According to our knowledge, this is the first systematic analysis of specific RF-EMF bio-effects in association to exposure quality, highlighting the need for more stringent quality procedures for the exposure conditions.

Adaptive response in mouse bone-marrow stromal cells exposed to 900-MHz radiofrequency fields: Gamma-radiation-induced DNA strand breaks and repair

The aim of this study was to examine whether radiofrequency field (RF) preexposure induced adaptive responses (AR) in mouse bone-marrow stromal cells (BMSC) and the mechanisms underlying the observed findings. Cells were preexposed to 900-MHz radiofrequency fields (RF) at 120 μW/cm(2) power intensity for 4 h/d for 5 d. Some cells were subjected to 1.5 Gy γ-radiation (GR) 4 h following the last RF exposure. The intensity of strand breaks in the DNA was assessed immediately at 4 h. Subsequently, some BMSC were examined at 30, 60, 90, or 120 min utilizing the alkaline comet assay and γ-H2AX foci technique. Data showed no significant differences in number and intensity of strand breaks in DNA between RF-exposed and control cells. A significant increase in number and intensity of DNA strand breaks was noted in cells exposed to GR exposure alone. RF followed by GR exposure significantly decreased number of strand breaks and resulted in faster kinetics of repair of DNA strand breaks compared to GR alone. Thus, data suggest that RF preexposure protected cells from damage induced by GR. Evidence indicates that in RF-mediated AR more rapid repair kinetics occurs under conditions of GR-induced damage, which may be attributed to diminished DNA strand breakage.

Outdoor characterization of radio frequency electromagnetic fields in a Spanish birth cohort

There is considerable public concern in many countries about the possible adverse effects of exposure to non-ionizing radiation electromagnetic fields, especially in vulnerable populations such as children. The aim of this study was to characterize environmental exposure profiles within the frequency range 100kHz-6GHz in the immediate surrounds of the dwellings of 123 families from the INMA-Granada birth cohort in Southern Spain, using spot measurements. The arithmetic mean root mean-square electric field (ERMS) and power density (SRMS) values were, respectively, 195.79mV/m (42.3% of data were above this mean) and 799.01µW/m(2) (30% of values were above this mean); median values were 148.80mV/m and 285.94µW/m(2), respectively. Exposure levels below the quantification limit were assigned a value of 0.01V/m. Incident field strength levels varied widely among different areas or towns/villages, demonstrating spatial variability in the distribution of exposure values related to the surface area population size and also among seasons. Although recorded values were well below International Commission for Non-Ionizing Radiation Protection reference levels, there is a particular need to characterize incident field strength levels in vulnerable populations (e.g., children) because of their chronic and ever-increasing exposure. The effects of incident field strength have not been fully elucidated; however, it may be appropriate to apply the precautionary principle in order to reduce exposure in susceptible groups.

Magnetic resonance imaging (MRI): A review of genetic damage investigations

Magnetic resonance imaging (MRI) is a powerful, non-invasive diagnostic medical imaging technique widely used to acquire detailed information about anatomy and function of different organs in the body, in both health and disease. It utilizes electromagnetic fields of three different frequency bands: static magnetic field (SMF), time-varying gradient magnetic fields (GMF) in the kHz range and pulsed radiofrequency fields (RF) in the MHz range. There have been some investigations examining the extent of genetic damage following exposure of bacterial and human cells to all three frequency bands of electromagnetic fields, as used during MRI: the rationale for these studies is the well documented evidence of positive correlation between significantly increased genetic damage and carcinogenesis. Overall, the published data were not sufficiently informative and useful because of the small sample size, inappropriate comparison of experimental groups, etc. Besides, when an increased damage was observed in MRI-exposed cells, the fate of such lesions was not further explored from multiple 'down-stream' events. This review provides: (i) information on the basic principles used in MRI technology, (ii) detailed experimental protocols, results and critical comments on the genetic damage investigations thus far conducted using MRI equipment and, (iii) a discussion on several gaps in knowledge in the current scientific literature on MRI. Comprehensive, international, multi-centered collaborative studies, using a common and widely used MRI exposure protocol (cardiac or brain scan) incorporating several genetic/epigenetic damage end-points as well as epidemiological investigations, in large number of individuals/patients are warranted to reduce and perhaps, eliminate uncertainties raised in genetic damage investigations in cells exposed in vitro and in vivo to MRI.