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Kundrát P, Pachnerová Brabcová K, Jelínek Michaelidesová A, Zahradníček O, Danilová I, Štěpán V, Jamborová Z, Davídková M. BORON-ENHANCED BIOLOGICAL EFFECTIVENESS OF PROTON IRRADIATION: STRATEGY TO ASSESS THE UNDERPINNING MECHANISM. RADIATION PROTECTION DOSIMETRY 2022; 198:527-531. [PMID: 36005957 DOI: 10.1093/rpd/ncac093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 05/22/2022] [Indexed: 06/15/2023]
Abstract
Proton radiotherapy for the treatment of cancer offers an excellent dose distribution. Cellular experiments have shown that in terms of biological effects, the sharp dose distribution is further amplified, by as much as 75%, in the presence of boron. It is a matter of debate whether the underlying physical processes involve the nuclear reaction of 11B with protons or 10B with secondary neutrons, both producing densely ionizing short-ranged particles. Likewise, potential roles of intercellular communication or boron acting as a radiosensitizer are not clear. We present an ongoing research project based on a multiscale approach to elucidate the mechanism by which boron enhances the effectiveness of proton irradiation in the Bragg peak. It combines experimental with simulation tools to study the physics of proton-boron interactions, and to analyze intra- and inter-cellular boron biology upon proton irradiation.
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Affiliation(s)
- Pavel Kundrát
- Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Na Truhlářce 39/64, 180 00 Praha 8, Czech Republic
| | - Kateřina Pachnerová Brabcová
- Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Na Truhlářce 39/64, 180 00 Praha 8, Czech Republic
| | - Anna Jelínek Michaelidesová
- Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Na Truhlářce 39/64, 180 00 Praha 8, Czech Republic
- Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, 110 00 Praha 1, Czech Republic
| | - Oldřich Zahradníček
- Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Na Truhlářce 39/64, 180 00 Praha 8, Czech Republic
| | - Irina Danilová
- Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Na Truhlářce 39/64, 180 00 Praha 8, Czech Republic
- Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, 110 00 Praha 1, Czech Republic
| | - Václav Štěpán
- Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Na Truhlářce 39/64, 180 00 Praha 8, Czech Republic
- Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, 110 00 Praha 1, Czech Republic
| | - Zuzana Jamborová
- Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Na Truhlářce 39/64, 180 00 Praha 8, Czech Republic
- Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, 110 00 Praha 1, Czech Republic
| | - Marie Davídková
- Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Na Truhlářce 39/64, 180 00 Praha 8, Czech Republic
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Kundrát P, Friedland W, Becker J, Eidemüller M, Ottolenghi A, Baiocco G. Analytical formulas representing track-structure simulations on DNA damage induced by protons and light ions at radiotherapy-relevant energies. Sci Rep 2020; 10:15775. [PMID: 32978459 PMCID: PMC7519066 DOI: 10.1038/s41598-020-72857-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/17/2020] [Indexed: 01/04/2023] Open
Abstract
Track structure based simulations valuably complement experimental research on biological effects of ionizing radiation. They provide information at the highest level of detail on initial DNA damage induced by diverse types of radiation. Simulations with the biophysical Monte Carlo code PARTRAC have been used for testing working hypotheses on radiation action mechanisms, for benchmarking other damage codes and as input for modelling subsequent biological processes. To facilitate such applications and in particular to enable extending the simulations to mixed radiation field conditions, we present analytical formulas that capture PARTRAC simulation results on DNA single- and double-strand breaks and their clusters induced in cells irradiated by ions ranging from hydrogen to neon at energies from 0.5 GeV/u down to their stopping. These functions offer a means by which radiation transport codes at the macroscopic scale could easily be extended to predict biological effects, exploiting a large database of results from micro-/nanoscale simulations, without having to deal with the coupling of spatial scales and running full track-structure calculations.
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Affiliation(s)
- Pavel Kundrát
- Institute of Radiation Medicine, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany.,Department of Radiation Dosimetry, Nuclear Physics Institute CAS, Prague, Czech Republic
| | - Werner Friedland
- Institute of Radiation Medicine, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Janine Becker
- Institute of Radiation Medicine, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Markus Eidemüller
- Institute of Radiation Medicine, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Andrea Ottolenghi
- Radiation Biophysics and Radiobiology Group, Physics Department, University of Pavia, Pavia, Italy
| | - Giorgio Baiocco
- Radiation Biophysics and Radiobiology Group, Physics Department, University of Pavia, Pavia, Italy.
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Mizuno T, Kinoshita S, Ito T, Maedera S, Kusuhara H. Development of Orthogonal Linear Separation Analysis (OLSA) to Decompose Drug Effects into Basic Components. Sci Rep 2019; 9:1824. [PMID: 30755704 PMCID: PMC6372619 DOI: 10.1038/s41598-019-38528-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 12/27/2018] [Indexed: 01/06/2023] Open
Abstract
Drugs have multiple, not single, effects. Decomposition of drug effects into basic components helps us to understand the pharmacological properties of a drug and contributes to drug discovery. We have extended factor analysis and developed a novel profile data analysis method: orthogonal linear separation analysis (OLSA). OLSA contracted 11,911 genes to 118 factors from transcriptome data of MCF7 cells treated with 318 compounds in a Connectivity Map. Ontology of the main genes constituting the factors detected significant enrichment of the ontology in 65 of 118 factors and similar results were obtained in two other data sets. In further analysis of the Connectivity Map data set, one factor discriminated two Hsp90 inhibitors, geldanamycin and radicicol, while clustering analysis could not. Doxorubicin and other topoisomerase inhibitors were estimated to inhibit Na+/K+ ATPase, one of the suggested mechanisms of doxorubicin-induced cardiotoxicity. Based on the factor including PI3K/AKT/mTORC1 inhibition activity, 5 compounds were predicted to be novel inducers of autophagy, and other analyses including western blotting revealed that 4 of the 5 actually induced autophagy. These findings indicate the potential of OLSA to decompose the effects of a drug and identify its basic components.
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Affiliation(s)
- Tadahaya Mizuno
- Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Setsuo Kinoshita
- Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- ProMedico Co., Ltd., Ota-ku, Tokyo, 143-0023, Japan
| | - Takuya Ito
- Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shotaro Maedera
- Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hiroyuki Kusuhara
- Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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Sergeeva VA, Ershova ES, Veiko NN, Malinovskaya EM, Kalyanov AA, Kameneva LV, Stukalov SV, Dolgikh OA, Konkova MS, Ermakov AV, Veiko VP, Izhevskaya VL, Kutsev SI, Kostyuk SV. Low-Dose Ionizing Radiation Affects Mesenchymal Stem Cells via Extracellular Oxidized Cell-Free DNA: A Possible Mediator of Bystander Effect and Adaptive Response. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:9515809. [PMID: 28904740 PMCID: PMC5585687 DOI: 10.1155/2017/9515809] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/17/2017] [Accepted: 05/18/2017] [Indexed: 12/26/2022]
Abstract
We have hypothesized that the adaptive response to low doses of ionizing radiation (IR) is mediated by oxidized cell-free DNA (cfDNA) fragments. Here, we summarize our experimental evidence for this model. Studies involving measurements of ROS, expression of the NOX (superoxide radical production), induction of apoptosis and DNA double-strand breaks, antiapoptotic gene expression and cell cycle inhibition confirm this hypothesis. We have demonstrated that treatment of mesenchymal stem cells (MSCs) with low doses of IR (10 cGy) leads to cell death of part of cell population and release of oxidized cfDNA. cfDNA has the ability to penetrate into the cytoplasm of other cells. Oxidized cfDNA, like low doses of IR, induces oxidative stress, ROS production, ROS-induced oxidative modifications of nuclear DNA, DNA breaks, arrest of the cell cycle, activation of DNA reparation and antioxidant response, and inhibition of apoptosis. The MSCs pretreated with low dose of irradiation or oxidized cfDNA were equally effective in induction of adaptive response to challenge further dose of radiation. Our studies suggest that oxidized cfDNA is a signaling molecule in the stress signaling that mediates radiation-induced bystander effects and that it is an important component of the development of radioadaptive responses to low doses of IR.
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Affiliation(s)
- V. A. Sergeeva
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - E. S. Ershova
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
- V. A. Negovsky Research Institute of General Reanimatology, Moscow 107031, Russia
| | - N. N. Veiko
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
- V. A. Negovsky Research Institute of General Reanimatology, Moscow 107031, Russia
| | | | - A. A. Kalyanov
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - L. V. Kameneva
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - S. V. Stukalov
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - O. A. Dolgikh
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - M. S. Konkova
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - A. V. Ermakov
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - V. P. Veiko
- Bach Institute of Biochemistry and Russian Academy of Sciences, 33 Leninskii Ave., Moscow 119071, Russia
| | - V. L. Izhevskaya
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - S. I. Kutsev
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
- N. I. Pirogov Russian National Research Medical University, Moscow 117997, Russia
| | - S. V. Kostyuk
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
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Kundrát P, Friedland W. Enhanced release of primary signals may render intercellular signalling ineffective due to spatial aspects. Sci Rep 2016; 6:33214. [PMID: 27645799 PMCID: PMC5028836 DOI: 10.1038/srep33214] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 08/03/2016] [Indexed: 11/30/2022] Open
Abstract
Detailed mechanistic modelling has been performed of the intercellular signalling cascade between precancerous cells and their normal neighbours that leads to a selective removal of the precancerous cells by apoptosis. Two interconnected signalling pathways that were identified experimentally have been modelled, explicitly accounting for temporal and spatial effects. The model predicts highly non-linear behaviour of the signalling. Importantly, under certain conditions, enhanced release of primary signals by precancerous cells renders the signalling ineffective. This counter-intuitive behaviour arises due to spatial aspects of the underlying signalling scheme: Increased primary signalling by precancerous cells does, upon reaction with factors derived from normal cells, produce higher yields of apoptosis-triggering molecules. However, the apoptosis-triggering signals are formed farther from the precancerous cells, so that these are attacked less efficiently. Spatial effects thus may represent a novel analogue of negative feedback mechanisms.
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Affiliation(s)
- Pavel Kundrát
- Institute of Radiation Protection, Department of Radiation Sciences, Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Werner Friedland
- Institute of Radiation Protection, Department of Radiation Sciences, Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Neuherberg, Germany
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Kundrát P, Friedland W. Mechanistic modelling of radiation-induced bystander effects. RADIATION PROTECTION DOSIMETRY 2015; 166:148-151. [PMID: 25877530 DOI: 10.1093/rpd/ncv170] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A model of radiation-induced bystander effects is presented that explicitly takes into account the transient nature of bystander signal emission post-irradiation, signal lifetime and the non-linear cellular response to the signals. Data are analysed on mutagenesis induced in human lymphoblasts in medium transfer experiments, in which the signal build-up time, medium dilution and the duration of reporter cells' exposure to the medium were varied. The model implies that the cellular release of bystander signals decreases rather slowly, with a characteristic time of about a day, whereas the signal itself decays with a lifetime of about an hour.
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Affiliation(s)
- P Kundrát
- Institute of Radiation Protection, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - W Friedland
- Institute of Radiation Protection, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
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Sato T, Hamada N. Model assembly for estimating cell surviving fraction for both targeted and nontargeted effects based on microdosimetric probability densities. PLoS One 2014; 9:e114056. [PMID: 25426641 PMCID: PMC4245256 DOI: 10.1371/journal.pone.0114056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 11/03/2014] [Indexed: 11/23/2022] Open
Abstract
We here propose a new model assembly for estimating the surviving fraction of cells irradiated with various types of ionizing radiation, considering both targeted and nontargeted effects in the same framework. The probability densities of specific energies in two scales, which are the cell nucleus and its substructure called a domain, were employed as the physical index for characterizing the radiation fields. In the model assembly, our previously established double stochastic microdosimetric kinetic (DSMK) model was used to express the targeted effect, whereas a newly developed model was used to express the nontargeted effect. The radioresistance caused by overexpression of anti-apoptotic protein Bcl-2 known to frequently occur in human cancer was also considered by introducing the concept of the adaptive response in the DSMK model. The accuracy of the model assembly was examined by comparing the computationally and experimentally determined surviving fraction of Bcl-2 cells (Bcl-2 overexpressing HeLa cells) and Neo cells (neomycin resistant gene-expressing HeLa cells) irradiated with microbeam or broadbeam of energetic heavy ions, as well as the WI-38 normal human fibroblasts irradiated with X-ray microbeam. The model assembly reproduced very well the experimentally determined surviving fraction over a wide range of dose and linear energy transfer (LET) values. Our newly established model assembly will be worth being incorporated into treatment planning systems for heavy-ion therapy, brachytherapy, and boron neutron capture therapy, given critical roles of the frequent Bcl-2 overexpression and the nontargeted effect in estimating therapeutic outcomes and harmful effects of such advanced therapeutic modalities.
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Affiliation(s)
- Tatsuhiko Sato
- Research Group for Radiation Protection, Nuclear Science and Engineering Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki, Japan
- * E-mail:
| | - Nobuyuki Hamada
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Komae, Tokyo, Japan
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Manda K, Kavanagh JN, Buttler D, Prise KM, Hildebrandt G. Low dose effects of ionizing radiation on normal tissue stem cells. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 761:6-14. [PMID: 24566131 DOI: 10.1016/j.mrrev.2014.02.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 02/03/2014] [Accepted: 02/13/2014] [Indexed: 12/18/2022]
Abstract
In recent years, there has been growing evidence for the involvement of stem cells in cancer initiation. As a result of their long life span, stem cells may have an increased propensity to accumulate genetic damage relative to differentiated cells. Therefore, stem cells of normal tissues may be important targets for radiation-induced carcinogenesis. Knowledge of the effects of ionizing radiation (IR) on normal stem cells and on the processes involved in carcinogenesis is very limited. The influence of high doses of IR (>5Gy) on proliferation, cell cycle and induction of senescence has been demonstrated in stem cells. There have been limited studies of the effects of moderate (0.5-5Gy) and low doses (<0.5Gy) of IR on stem cells however, the effect of low dose IR (LD-IR) on normal stem cells as possible targets for radiation-induced carcinogenesis has not been studied in any depth. There may also be important parallels between stem cell responses and those of cancer stem cells, which may highlight potential key common mechanisms of their response and radiosensitivity. This review will provide an overview of the current knowledge of radiation-induced effects on normal stem cells, with particular focus on low and moderate doses of IR.
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Affiliation(s)
- Katrin Manda
- Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock, Germany.
| | - Joy N Kavanagh
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom.
| | - Dajana Buttler
- Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock, Germany.
| | - Kevin M Prise
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom.
| | - Guido Hildebrandt
- Department of Radiotherapy and Radiation Oncology, University of Rostock, Suedring 75, 18059 Rostock, Germany.
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Campa A, Balduzzi M, Dini V, Esposito G, Tabocchini MA. The complex interactions between radiation induced non-targeted effects and cancer. Cancer Lett 2013; 356:126-36. [PMID: 24139968 DOI: 10.1016/j.canlet.2013.09.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 09/11/2013] [Accepted: 09/26/2013] [Indexed: 01/19/2023]
Abstract
Radiation induced non-targeted effects have been widely investigated in the last two decades for their potential impact on low dose radiation risk. In this paper we will give an overview of the most relevant aspects related to these effects, starting from the definition of the low dose scenarios. We will underline the role of radiation quality, both in terms of mechanisms of interaction with the biological matter and for the importance of charged particles as powerful tools for low dose effects investigation. We will focus on cell communication, representing a common feature of non-targeted effects, giving also an overview of cancer models that have explicitly considered such effects.
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Affiliation(s)
- Alessandro Campa
- Istituto Superiore di Sanità (ISS), Rome, Italy; Istituto Nazionale di Fisica Nucleare (INFN), Sezione Roma1, Gruppo Collegato Sanità, Rome, Italy
| | - Maria Balduzzi
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione Roma1, Gruppo Collegato Sanità, Rome, Italy; Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), Rome, Italy
| | - Valentina Dini
- Istituto Superiore di Sanità (ISS), Rome, Italy; Istituto Nazionale di Fisica Nucleare (INFN), Sezione Roma1, Gruppo Collegato Sanità, Rome, Italy
| | - Giuseppe Esposito
- Istituto Superiore di Sanità (ISS), Rome, Italy; Istituto Nazionale di Fisica Nucleare (INFN), Sezione Roma1, Gruppo Collegato Sanità, Rome, Italy
| | - Maria Antonella Tabocchini
- Istituto Superiore di Sanità (ISS), Rome, Italy; Istituto Nazionale di Fisica Nucleare (INFN), Sezione Roma1, Gruppo Collegato Sanità, Rome, Italy.
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Panagopoulos DJ, Johansson O, Carlo GL. Evaluation of specific absorption rate as a dosimetric quantity for electromagnetic fields bioeffects. PLoS One 2013; 8:e62663. [PMID: 23750202 PMCID: PMC3672148 DOI: 10.1371/journal.pone.0062663] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 03/22/2013] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. METHODS We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect. RESULTS WE FIND THAT: a) The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b) All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c) The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured. CONCLUSIONS SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc) which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar uncertainty to predict the biological effect due to non-linearity.
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