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Yadav H, Sharma RS, Singh R. Immunotoxicity of radiofrequency radiation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 309:119793. [PMID: 35863710 DOI: 10.1016/j.envpol.2022.119793] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/27/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Growing evidence recommends that radiofrequency radiations might be a new type of environmental pollutant. The consequences of RFR on the human immune system have gained considerable interest in recent years, not only to examine probable negative effects on health but also to understand if RFR can modulate the immune response positively. Although several studies have been published on the immune effects of RFR but no satisfactory agreement has been reached. Hence this review aims to evaluate the RFR modulating impacts on particular immune cells contributing to various innate or adaptive immune responses. In view of existing pieces of evidence, we have suggested an intracellular signaling cascade responsible for RFR action. The bio-effects of RFR on immune cell morphology, viability, proliferation, genome integrity, and immune functions such as ROS, cytokine secretion, phagocytosis, apoptosis, etc. are discussed. The majority of existing evidence point toward the possible shifts in the activity, number, and/or function of immunocompetent cells, but the outcome of several studies is still contradictory and needs further studies to reach a conclusion. Also, the direct association of experimental studies to human risks might not be helpful as exposure parameters vary in real life. On the basis of recent available literature, we suggest that special experiments should be designed to test each particular signal utilized in communication technologies to rule out the hypothesis that longer exposure to RFR emitting devices would affect the immunity by inducing genotoxic effects in human immune cells.
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Affiliation(s)
- Himanshi Yadav
- Department of Environmental Studies, Satyawati College, University of Delhi, Delhi, 110052, India
| | | | - Rajeev Singh
- Department of Environmental Studies, Satyawati College, University of Delhi, Delhi, 110052, India.
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Gulati S, Kosik P, Durdik M, Skorvaga M, Jakl L, Markova E, Belyaev I. Effects of different mobile phone UMTS signals on DNA, apoptosis and oxidative stress in human lymphocytes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 267:115632. [PMID: 33254645 DOI: 10.1016/j.envpol.2020.115632] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/07/2020] [Accepted: 09/09/2020] [Indexed: 06/12/2023]
Abstract
Different scientific reports suggested link between exposure to radiofrequency radiation (RF) from mobile communications and induction of reactive oxygen species (ROS) and DNA damage while other studies have not found such a link. However, the available studies are not directly comparable because they were performed at different parameters of exposure, including carrier frequency of RF signal, which was shown to be a critical for appearance of the RF effects. For the first time, we comparatively analyzed genotoxic effects of UMTS signals at different frequency channels used by 3G mobile phones (1923, 1947.47, and 1977 MHz). Genotoxicity was examined in human lymphocytes exposed to RF for 1 h and 3 h using complimentary endpoints such as induction of ROS by imaging flow cytometry, DNA damage by alkaline comet assay, mutations in TP53 gene by RSM assay, preleukemic fusion genes (PFG) by RT-qPCR, and apoptosis by flow cytometry. No effects of RF exposure on ROS, apoptosis, PFG, and mutations in TP53 gene were revealed regardless the UMTS frequency while inhibition of a bulk RNA expression was found. On the other hand, we found relatively small but statistically significant induction of DNA damage in dependence on UMTS frequency channel with maximal effect at 1977.0 MHz. Our data support a notion that each specific signal used in mobile communication should be tested in specially designed experiments to rule out that prolonged exposure to RF from mobile communication would induce genotoxic effects and affect the health of human population.
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Affiliation(s)
- Sachin Gulati
- Department of Radiobiology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, 845 05, Slovak Republic
| | - Pavol Kosik
- Department of Radiobiology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, 845 05, Slovak Republic
| | - Matus Durdik
- Department of Radiobiology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, 845 05, Slovak Republic
| | - Milan Skorvaga
- Department of Radiobiology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, 845 05, Slovak Republic
| | - Lukas Jakl
- Department of Radiobiology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, 845 05, Slovak Republic
| | - Eva Markova
- Department of Radiobiology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, 845 05, Slovak Republic
| | - Igor Belyaev
- Department of Radiobiology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, 845 05, Slovak Republic.
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Makinistian L, Muehsam DJ, Bersani F, Belyaev I. Some recommendations for experimental work in magnetobiology, revisited. Bioelectromagnetics 2018; 39:556-564. [DOI: 10.1002/bem.22144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 09/03/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Leonardo Makinistian
- Department of Physics and Instituto de Física Aplicada (INFAP); Universidad Nacional de San Luis-CONICET; San Luis Argentina
- Department of Radiobiology; Cancer Research Institute, Biomedical Research Center; Slovak Academy of Science; Bratislava Slovakia
| | - David J. Muehsam
- National Institute of Biostructures and Biosystems; Bologna Italy
| | - Ferdinando Bersani
- National Institute of Biostructures and Biosystems; Bologna Italy
- DIFA Department of Physics and Astronomy; University of Bologna; Bologna Italy
| | - Igor Belyaev
- Department of Radiobiology; Cancer Research Institute, Biomedical Research Center; Slovak Academy of Science; Bratislava Slovakia
- Laboratory of Radiobiology; Prokhorov General Physics Institute; Russian Academy of Science; Moscow Russia
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Belyaev I, Dean A, Eger H, Hubmann G, Jandrisovits R, Kern M, Kundi M, Moshammer H, Lercher P, Müller K, Oberfeld G, Ohnsorge P, Pelzmann P, Scheingraber C, Thill R. EUROPAEM EMF Guideline 2016 for the prevention, diagnosis and treatment of EMF-related health problems and illnesses. REVIEWS ON ENVIRONMENTAL HEALTH 2016; 31:363-397. [PMID: 27454111 DOI: 10.1515/reveh-2016-0011] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/29/2016] [Indexed: 06/06/2023]
Abstract
Chronic diseases and illnesses associated with non-specific symptoms are on the rise. In addition to chronic stress in social and work environments, physical and chemical exposures at home, at work, and during leisure activities are causal or contributing environmental stressors that deserve attention by the general practitioner as well as by all other members of the health care community. It seems necessary now to take "new exposures" like electromagnetic fields (EMF) into account. Physicians are increasingly confronted with health problems from unidentified causes. Studies, empirical observations, and patient reports clearly indicate interactions between EMF exposure and health problems. Individual susceptibility and environmental factors are frequently neglected. New wireless technologies and applications have been introduced without any certainty about their health effects, raising new challenges for medicine and society. For instance, the issue of so-called non-thermal effects and potential long-term effects of low-dose exposure were scarcely investigated prior to the introduction of these technologies. Common electromagnetic field or EMF sources: Radio-frequency radiation (RF) (3 MHz to 300 GHz) is emitted from radio and TV broadcast antennas, Wi-Fi access points, routers, and clients (e.g. smartphones, tablets), cordless and mobile phones including their base stations, and Bluetooth devices. Extremely low frequency electric (ELF EF) and magnetic fields (ELF MF) (3 Hz to 3 kHz) are emitted from electrical wiring, lamps, and appliances. Very low frequency electric (VLF EF) and magnetic fields (VLF MF) (3 kHz to 3 MHz) are emitted, due to harmonic voltage and current distortions, from electrical wiring, lamps (e.g. compact fluorescent lamps), and electronic devices. On the one hand, there is strong evidence that long-term exposure to certain EMFs is a risk factor for diseases such as certain cancers, Alzheimer's disease, and male infertility. On the other hand, the emerging electromagnetic hypersensitivity (EHS) is more and more recognized by health authorities, disability administrators and case workers, politicians, as well as courts of law. We recommend treating EHS clinically as part of the group of chronic multisystem illnesses (CMI), but still recognizing that the underlying cause remains the environment. In the beginning, EHS symptoms occur only occasionally, but over time they may increase in frequency and severity. Common EHS symptoms include headaches, concentration difficulties, sleep problems, depression, a lack of energy, fatigue, and flu-like symptoms. A comprehensive medical history, which should include all symptoms and their occurrences in spatial and temporal terms and in the context of EMF exposures, is the key to making the diagnosis. The EMF exposure is usually assessed by EMF measurements at home and at work. Certain types of EMF exposure can be assessed by asking about common EMF sources. It is very important to take the individual susceptibility into account. The primary method of treatment should mainly focus on the prevention or reduction of EMF exposure, that is, reducing or eliminating all sources of high EMF exposure at home and at the workplace. The reduction of EMF exposure should also be extended to public spaces such as schools, hospitals, public transport, and libraries to enable persons with EHS an unhindered use (accessibility measure). If a detrimental EMF exposure is reduced sufficiently, the body has a chance to recover and EHS symptoms will be reduced or even disappear. Many examples have shown that such measures can prove effective. To increase the effectiveness of the treatment, the broad range of other environmental factors that contribute to the total body burden should also be addressed. Anything that supports homeostasis will increase a person's resilience against disease and thus against the adverse effects of EMF exposure. There is increasing evidence that EMF exposure has a major impact on the oxidative and nitrosative regulation capacity in affected individuals. This concept also may explain why the level of susceptibility to EMF can change and why the range of symptoms reported in the context of EMF exposures is so large. Based on our current understanding, a treatment approach that minimizes the adverse effects of peroxynitrite - as has been increasingly used in the treatment of multisystem illnesses - works best. This EMF Guideline gives an overview of the current knowledge regarding EMF-related health risks and provides recommendations for the diagnosis, treatment and accessibility measures of EHS to improve and restore individual health outcomes as well as for the development of strategies for prevention.
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Mihoub M, El May A, Aloui A, Chatti A, Landoulsi A. Effects of static magnetic fields on growth and membrane lipid composition of Salmonella typhimurium wild-type and dam mutant strains. Int J Food Microbiol 2012; 157:259-66. [PMID: 22682582 DOI: 10.1016/j.ijfoodmicro.2012.05.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 04/22/2012] [Accepted: 05/18/2012] [Indexed: 01/12/2023]
Abstract
This study was carried out to explore the adaptive mechanisms of S. typhimurium particularly, the implication of the Dam methyltransferase in the remodelling of membrane lipid composition to overcome magnetic field stress. With this aim, we focused our analyses on the increase in viable numbers and membrane lipid modifications of S. typhimurium wild-type and dam mutant cells exposed for 10h to static magnetic fields (SMF; 200 mT). For the wild-type strain, exposure to SMF induced a significant decrease (p<0.05) of CFU at 6h, followed by an increase between 8 and 10h. Growth of the dam mutant was significantly affected (p<0.05) after 6h and no recovery was observed until 10h, highlighting a different behavior of SMF stressed wild-type and dam mutant strains. SMF significantly affected the phospholipid proportions in the two strains. The most affected were those of the acidic phospholipids, cardiolipins (CL). In the dam strain the phospholipid response to SMF followed a globally similar trend as in the wild-type with however lower effects, leading mainly to an unusual accumulation of CL. This would in part explain the different behavior of the wild-type and the dam strain. Results showed a significant increase of membrane cyclic fatty acids Cyc17 and Cyc19 in the wild-type strain but only the Cyc17 in the dam strain and a meaningful increase of the total unsaturated fatty acids (UFAs) to total saturated fatty acids (SFAs) ratios of the exposed cells compared to controls from 3 to 9h (p<0.05) for both strains. The net increase of the total UFAs to total SFAs ratios seemed to result mainly from the increase of (C18:1) proportion (p<0.05) and to a lower extent from that of (C16:1) (p<0.05). These modifications of cyclic and unsaturated fatty acid proportions constitute an adaptive response to SMF stress in S. typhimurium wild-type and dam mutants to maintain an optimum level of membrane fluidity under SMF.
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Affiliation(s)
- Mouadh Mihoub
- Unité de Biochimie des Lipides et Interaction des Macromolécules en Biologie (03/UR/0902), Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Zarzouna, Bizerte, Tunisia.
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Rodríguez-De la Fuente AO, Alcocer-González JM, Heredia-Rojas JA, Rodríguez-Padilla C, Rodríguez-Flores LE, Santoyo-Stephano MA, Castañeda-Garza E, Taméz-Guerra RS. Effect of 60 Hz electromagnetic fields on the activity of hsp70 promoter: an in vivo study. CELL BIOLOGY INTERNATIONAL REPORTS 2012; 19:e00014. [PMID: 23124775 PMCID: PMC3476825 DOI: 10.1042/cbr20110010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 01/10/2012] [Indexed: 11/17/2022]
Abstract
Exposure to EMFs (electromagnetic fields) results in a number of important biological changes, including modification of genetic expression. We have investigated the effect of 60 Hz sinusoidal EMFs at a magnetic flux density of 80 μT on the expression of the luciferase gene contained in a plasmid labelled as pEMF (EMF plasmid). This gene construct contains the specific sequences for the induction of hsp70 (heat-shock protein 70) expression by EMFs, as well as the reporter for the luciferase gene. The pEMF vector was electrotransferred into quadriceps muscles of BALB/c mice that were later exposed to EMFs. Increased luciferase expression was observed in mice exposed to EMFs 2 h daily for 7 days compared with controls (P<0.05). These data along with other reports in the literature suggest that EMFs can have far-reaching effects on the genome.
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Affiliation(s)
- Abraham O. Rodríguez-De la Fuente
- *Universidad Autnoma de Nuevo Len, UANL, Facultad de Ciencias
Biolgicas, Av. Universidad sn Ciudad Universitaria San Nicols de los
Garza Nuevo Len, C.P. 66451, Mexico
| | - Juan M. Alcocer-González
- *Universidad Autnoma de Nuevo Len, UANL, Facultad de Ciencias
Biolgicas, Av. Universidad sn Ciudad Universitaria San Nicols de los
Garza Nuevo Len, C.P. 66451, Mexico
| | - J. Antonio Heredia-Rojas
- *Universidad Autnoma de Nuevo Len, UANL, Facultad de Ciencias
Biolgicas, Av. Universidad sn Ciudad Universitaria San Nicols de los
Garza Nuevo Len, C.P. 66451, Mexico
| | - Cristina Rodríguez-Padilla
- *Universidad Autnoma de Nuevo Len, UANL, Facultad de Ciencias
Biolgicas, Av. Universidad sn Ciudad Universitaria San Nicols de los
Garza Nuevo Len, C.P. 66451, Mexico
| | - Laura E. Rodríguez-Flores
- †Universidad Autnoma de Nuevo Len, UANL, Facultad de
Medicina, Av. Universidad sn Ciudad Universitaria San Nicols de los
Garza Nuevo Len, C.P. 66451, Mexico
| | - Martha A. Santoyo-Stephano
- *Universidad Autnoma de Nuevo Len, UANL, Facultad de Ciencias
Biolgicas, Av. Universidad sn Ciudad Universitaria San Nicols de los
Garza Nuevo Len, C.P. 66451, Mexico
| | - Esperanza Castañeda-Garza
- *Universidad Autnoma de Nuevo Len, UANL, Facultad de Ciencias
Biolgicas, Av. Universidad sn Ciudad Universitaria San Nicols de los
Garza Nuevo Len, C.P. 66451, Mexico
| | - Reyes S. Taméz-Guerra
- *Universidad Autnoma de Nuevo Len, UANL, Facultad de Ciencias
Biolgicas, Av. Universidad sn Ciudad Universitaria San Nicols de los
Garza Nuevo Len, C.P. 66451, Mexico
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Sarimov R, Alipov ED, Belyaev IY. Fifty hertz magnetic fields individually affect chromatin conformation in human lymphocytes: Dependence on amplitude, temperature, and initial chromatin state. Bioelectromagnetics 2011; 32:570-9. [DOI: 10.1002/bem.20674] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 03/19/2011] [Indexed: 11/10/2022]
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Heredia-Rojas JA, Rodríguez de la Fuente AO, Alcocer González JM, Rodríguez-Flores LE, Rodríguez-Padilla C, Santoyo-Stephano MA, Castañeda-Garza E, Taméz-Guerra RS. Effect of 60 Hz magnetic fields on the activation of hsp70 promoter in cultured INER-37 and RMA E7 cells. In Vitro Cell Dev Biol Anim 2010; 46:758-63. [PMID: 20835776 DOI: 10.1007/s11626-010-9342-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 08/19/2010] [Indexed: 11/26/2022]
Abstract
It has been reported that 50-60 Hz magnetic fields (MF) with flux densities ranging from microtesla to millitesla are able to induce heat shock factor or heat shock proteins in various cells. In this study, we investigated the effect of 60 Hz sinusoidal MF at 8 and 80 μT on the expression of the luciferase gene contained in a plasmid labeled as electromagnetic field-plasmid (pEMF). This gene construct contains the specific sequences previously described for the induction of hsp70 expression by MF, as well as the reporter for the luciferase gene. The pEMF vector was transfected into INER-37 and RMA E7 cell lines that were later exposed to either MF or thermal shock (TS). Cells that received the MF or TS treatments and their controls were processed according to the luciferase assay system for evaluate luciferase activity. An increased luciferase gene expression was observed in INER-37 cells exposed to MF and TS compared with controls (p < 0.05), but MF exposure had no effect on the RMA E7 cell line.
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Affiliation(s)
- J Antonio Heredia-Rojas
- Departamento de Ciencias Exactas y Desarrollo Humano, Facultad de Ciencias Biológicas, UANL, Serafín Peña #909 Norte, Monterrey, Nuevo León C.P. 64000, Mexico.
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László J, Kutasi J. Static magnetic field exposure fails to affect the viability of different bacteria strains. Bioelectromagnetics 2010; 31:220-5. [PMID: 19821495 DOI: 10.1002/bem.20551] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The viability of the microbes Saccharomyces cerevisiae, Bacillus circulans, Escherichia coli, Micrococcus luteus, Pseudomonas fluorescens, Salmonella enteritidis, Serratia marcescens, and Staphylococcus aureus was tested under static magnetic field exposure up to 24 h in either a homogeneous (159.2 +/- 13.4 mT) or three types of inhomogeneous static magnetic fields: (i) peak-to-peak magnetic flux density 476.7 +/- 0.1 mT with a lateral magnetic flux density gradient of 47.7 T/m, (ii) 12.0 +/- 0.1 mT with 1.2 T/m, or (iii) 2.8 +/- 0.1 mT with 0.3 T/m. Even the longest period of exposure failed to produce any effect in the growth of bacteriae that could be correlated with static magnetic field exposure.
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Affiliation(s)
- János László
- Section for Mathematics, Hungarian Academy of Sciences, Nádor u. 7, Budapest, Hungary.
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Markovà E, Malmgren LO, Belyaev IY. Microwaves from Mobile Phones Inhibit 53BP1 Focus Formation in Human Stem Cells More Strongly Than in Differentiated Cells: Possible Mechanistic Link to Cancer Risk. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:394-399. [PMID: 20064781 PMCID: PMC2854769 DOI: 10.1289/ehp.0900781] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 10/22/2009] [Indexed: 05/26/2023]
Abstract
BACKGROUND It is widely accepted that DNA double-strand breaks (DSBs) and their misrepair in stem cells are critical events in the multistage origination of various leukemias and tumors, including gliomas. OBJECTIVES We studied whether microwaves from mobile telephones of the Global System for Mobile Communication (GSM) and the Universal Global Telecommunications System (UMTS) induce DSBs or affect DSB repair in stem cells. METHODS We analyzed tumor suppressor TP53 binding protein 1 (53BP1) foci that are typically formed at the sites of DSB location (referred to as DNA repair foci) by laser confocal microscopy. RESULTS 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. CONCLUSIONS 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.
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Affiliation(s)
- Eva Markovà
- Department of Genetics, Microbiology and Toxicology, Stockholm University, Stockholm, Sweden
- Laboratory of Molecular Genetics, Cancer Research Institute, Bratislava, Slovak Republic
| | | | - Igor Y. Belyaev
- Department of Genetics, Microbiology and Toxicology, Stockholm University, Stockholm, Sweden
- Laboratory of Molecular Genetics, Cancer Research Institute, Bratislava, Slovak Republic
- Laboratory of Radiobiology, General Physics Institute, Russian Academy of Science, Moscow, Russia
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Belyaev IY. Radiation-induced DNA repair foci: spatio-temporal aspects of formation, application for assessment of radiosensitivity and biological dosimetry. Mutat Res 2010; 704:132-41. [PMID: 20096808 DOI: 10.1016/j.mrrev.2010.01.011] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 12/26/2009] [Accepted: 01/13/2010] [Indexed: 10/19/2022]
Abstract
Several proteins involved in DNA repair and DNA damage signaling have been shown to produce discrete foci in response to ionizing radiation. These foci are believed to co-localize to DSB and referred to as ionizing radiation-induced foci (IRIF) or DNA repair foci. Recent studies have revealed that some residual IRIF remain in cells for a relatively long time after irradiation, and have indicated a possible correlation between radiosensitivity of cells and residual IRIF. Remarkably, residual foci are significantly larger in size than the initial foci. Increase in the size of IRIF with time upon irradiation has been found in various cell types and has partially been correlated with dynamics and fusion of initial foci. Although it is admitted that the number of IRIF reflect that of DSB, several studies report a lack of correlation between kinetics for IRIF and DSB and a lack of co-localization between DSB repair proteins. These studies suggest that some proportion of residual IRIF that depend on cell type, dose, and post-irradiation time may represent alternations in chromatin structure after DSB have been repaired or misrepaired. While precise functions of residual foci are presently unknown, their possible link to remaining chromatin alternations, nuclear matrix, apoptosis, delayed repair and misrejoining of DSB, activity of several kinases, phosphatases, and checkpoint signaling has been suggested. Another intriguing possibility is that some of DNA repair foci may mark break-points at chromosomal aberrations (CA). While this possibility has not been confirmed substantially, the residual foci seem to be useful for biological dosimetry and estimation of individual radiosensitivity in radiotherapy of cancer.
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Affiliation(s)
- I Y Belyaev
- Laboratory of Molecular Genetics, Cancer Research Institute, Bratislava, Slovak Republic.
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Blackman C. Cell phone radiation: Evidence from ELF and RF studies supporting more inclusive risk identification and assessment. PATHOPHYSIOLOGY 2009; 16:205-16. [PMID: 19264460 DOI: 10.1016/j.pathophys.2009.02.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 02/03/2009] [Accepted: 02/03/2009] [Indexed: 11/25/2022] Open
Abstract
Many national and international exposure standards for maximum radiation exposure from the use of cell phone and other similar portable devices are ultimately based on the production of heat particularly in regions of the head, that is, thermal effects (TE). The recent elevation in some countries of the allowable exposure, that is, averaging the exposure that occurs in a 6min period over 10g of tissue rather than over 1g allows for greater heating in small portions of the 10-g volume compared to the exposure that would be allowed averaged over 1-g volume. There is concern that 'hot' spots, that is, momentary higher intensities, could occur in portions of the 10-g tissue piece, might have adverse consequences, particularly in brain tissue. There is another concern about exposure to cell phone radiation that has been virtually ignored except for the National Council of Radiation Protection and Measurements (NCRP) advice given in a publication in 1986 [National Council for Radiation Protection and Measurements, Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields, National Council for Radiation Protection and Measurements, 1986, 400 pp.]. This NCRP review and guidance explicitly acknowledge the existence of non-thermal effects (NTE), and included provisions for reduced maximum-allowable limits should certain radiation characteristics occur during the exposure. If we are to take most current national and international exposure standards as completely protective of thermal injury for acute exposure only (6min time period) then the recent evidence from epidemiological studies associating increases in brain and head cancers with increased cell phone use per day and per year over 8-12 years, raises concerns about the possible health consequences on NTE first acknowledged in the NCRP 1986 report [National Council for Radiation Protection and Measurements, Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields, National Council for Radiation Protection and Measurements, 1986, 400 pp.]. This paper will review some of the salient evidence that demonstrates the existence of NTE and the exposure complexities that must be considered and understood to provide appropriate, more thorough evaluation and guidance for future studies and for assessment of potential health consequences. Unfortunately, this paper is necessary because most national and international reviews of the research area since the 1986 report [National Council for Radiation Protection and Measurements, Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields, National Council for Radiation Protection and Measurements, 1986, 400 pp.] have not included scientists with expertise in NTE, or given appropriate attention to their requests to include NTE in the establishment of public-health-based radiation exposure standards. Thus, those standards are limited because they are not comprehensive.
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