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Track Structure-Based Simulations on DNA Damage Induced by Diverse Isotopes. Int J Mol Sci 2022; 23:ijms232213693. [PMID: 36430172 PMCID: PMC9690858 DOI: 10.3390/ijms232213693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/01/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
Diverse isotopes such as 2H, 3He, 10Be, 11C and 14C occur in nuclear reactions in ion beam radiotherapy, in cosmic ray shielding, or are intentionally accelerated in dating techniques. However, only a few studies have specifically addressed the biological effects of diverse isotopes and were limited to energies of several MeV/u. A database of simulations with the PARTRAC biophysical tool is presented for H, He, Li, Be, B and C isotopes at energies from 0.5 GeV/u down to stopping. The doses deposited to a cell nucleus and also the yields per unit dose of single- and double-strand breaks and their clusters induced in cellular DNA are predicted to vary among diverse isotopes of the same element at energies < 1 MeV/u, especially for isotopes of H and He. The results may affect the risk estimates for astronauts in deep space missions or the models of biological effectiveness of ion beams and indicate that radiation protection in 14C or 10Be dating techniques may be based on knowledge gathered with 12C or 9Be.
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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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Friedland W, Schmitt E, Kundrát P, Baiocco G, Ottolenghi A. Track-structure simulations of energy deposition patterns to mitochondria and damage to their DNA. Int J Radiat Biol 2018; 95:3-11. [PMID: 29584515 DOI: 10.1080/09553002.2018.1450532] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE Mitochondria have been implicated in initiating and/or amplifying the biological effects of ionizing radiation not mediated via damage to nuclear DNA. To help elucidate the underlying mechanisms, energy deposition patterns to mitochondria and radiation damage to their DNA have been modelled. METHODS Track-structure simulations have been performed with PARTRAC biophysical tool for 60Co γ-rays and 5 MeV α-particles. Energy deposition to the cell's mitochondria has been analyzed. A model of mitochondrial DNA reflecting experimental information on its structure has been developed and used to assess its radiation-induced damage. RESULTS Energy deposition to mitochondria is highly inhomogeneous, especially at low doses. Although a dose-dependent fraction of mitochondria sees no energy deposition at all, the hit ones receive rather high amounts of energy. Nevertheless, only little damage to mitochondrial DNA occurs, even at large doses. CONCLUSION Mitochondrial DNA does not represent a critical target for radiation effects. Likely, the key role of mitochondria in radiation-induced biological effects arises from the communication between mitochondria and/or with the nucleus. Through this signaling, initial modifications in a few heavily hit mitochondria seem to be amplified to a massive long-term effect manifested in the whole cell or even tissue.
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Affiliation(s)
- Werner Friedland
- a Institute of Radiation Protection, Helmholtz Zentrum München - German Research Center for Environmental Health , Neuherberg , Germany
| | - Elke Schmitt
- a Institute of Radiation Protection, Helmholtz Zentrum München - German Research Center for Environmental Health , Neuherberg , Germany
| | - Pavel Kundrát
- a Institute of Radiation Protection, Helmholtz Zentrum München - German Research Center for Environmental Health , Neuherberg , Germany
| | - Giorgio Baiocco
- b Department of Physics , University of Pavia , Pavia , Italy
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Matsuya Y, Sasaki K, Yoshii Y, Okuyama G, Date H. Integrated Modelling of Cell Responses after Irradiation for DNA-Targeted Effects and Non-Targeted Effects. Sci Rep 2018; 8:4849. [PMID: 29555939 PMCID: PMC5859303 DOI: 10.1038/s41598-018-23202-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/07/2018] [Indexed: 01/10/2023] Open
Abstract
Intercellular communication after ionizing radiation exposure, so-called non-targeted effects (NTEs), reduces cell survival. Here we describe an integrated cell-killing model considering NTEs and DNA damage along radiation particle tracks, known as DNA-targeted effects (TEs) based on repair kinetics of DNA damage. The proposed model was applied to a series of experimental data, i.e., signal concentration, DNA damage kinetics, cell survival curve and medium transfer bystander effects (MTBEs). To reproduce the experimental data, the model considers the following assumptions: (i) the linear-quadratic (LQ) function as absorbed dose to express the hit probability to emit cell-killing signals, (ii) the potentially repair of DNA lesions induced by NTEs, and (iii) lower efficiency of repair for the damage in NTEs than that in TEs. By comparing the model results with experimental data, we found that signal-induced DNA damage and lower repair efficiency in non-hit cells are responsible for NTE-related repair kinetics of DNA damage, cell survival curve with low-dose hyper-radiosensitivity (HRS) and MTBEs. From the standpoint of modelling, the integrated cell-killing model with the LQ relation and a different repair function for NTEs provide a reasonable signal-emission probability and a new estimation of low-dose HRS linked to DNA repair efficiency.
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Affiliation(s)
- Yusuke Matsuya
- Graduate School of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, 060-0812, Japan
| | - Kohei Sasaki
- Faculty of Health Sciences, Hokkaido University of Science, Maeda 7-15, Teine-ku, Sapporo, 006-8585, Japan
| | - Yuji Yoshii
- Biological Research, Education and Instrumentation Center, Sapporo Medical University, Minami-1, Nichi-17, Chuo-ku, Sapporo, 060-8556, Japan
| | - Go Okuyama
- Faculty of Health Sciences, Hokkaido University of Science, Maeda 7-15, Teine-ku, Sapporo, 006-8585, Japan
| | - Hiroyuki Date
- Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, 060-0812, Japan.
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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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Cunha M, Testa E, Komova OV, Nasonova EA, Mel'nikova LA, Shmakova NL, Beuve M. Modeling cell response to low doses of photon irradiation: Part 2--application to radiation-induced chromosomal aberrations in human carcinoma cells. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2016; 55:31-40. [PMID: 26708100 DOI: 10.1007/s00411-015-0622-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/11/2015] [Indexed: 06/05/2023]
Abstract
The biological phenomena observed at low doses of ionizing radiation (adaptive response, bystander effects, genomic instability, etc.) are still not well understood. While at high irradiation doses, cellular death may be directly linked to DNA damage, at low doses, other cellular structures may be involved in what are known as non-(DNA)-targeted effects. Mitochondria, in particular, may play a crucial role through their participation in a signaling network involving oxygen/nitrogen radical species. According to the size of the implicated organelles, the fluctuations in the energy deposited into these target structures may impact considerably the response of cells to low doses of ionizing irradiation. Based on a recent simulation of these fluctuations, a theoretical framework was established to have further insight into cell responses to low doses of photon irradiation, namely the triggering of radioresistance mechanisms by energy deposition into specific targets. Three versions of a model are considered depending on the target size and on the number of targets that need to be activated by energy deposition to trigger radioresistance mechanisms. These model versions are applied to the fraction of radiation-induced chromosomal aberrations measured at low doses in human carcinoma cells (CAL51). For this cell line, it was found in the present study that the mechanisms of radioresistance could not be triggered by the activation of a single small target (nanometric size, 100 nm), but could instead be triggered by the activation of a large target (micrometric, 10 μm) or by the activation of a great number of small targets. The mitochondria network, viewed either as a large target or as a set of small units, might be concerned by these low-dose effects.
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Affiliation(s)
- Micaela Cunha
- Université de Lyon, 69622, Lyon, France
- Université de Lyon 1, Villeurbanne, France
- CNRS/IN2P3, Institut de Physique Nucléaire de Lyon, Villeurbanne, France
| | - Etienne Testa
- Université de Lyon, 69622, Lyon, France
- Université de Lyon 1, Villeurbanne, France
- CNRS/IN2P3, Institut de Physique Nucléaire de Lyon, Villeurbanne, France
| | - Olga V Komova
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow Region, Russia
| | - Elena A Nasonova
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow Region, Russia
| | - Larisa A Mel'nikova
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow Region, Russia
| | - Nina L Shmakova
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Dubna, Moscow Region, Russia
| | - Michaël Beuve
- Université de Lyon, 69622, Lyon, France.
- Université de Lyon 1, Villeurbanne, France.
- CNRS/IN2P3, Institut de Physique Nucléaire de Lyon, Villeurbanne, France.
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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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Byrne HL, Domanova W, McNamara AL, Incerti S, Kuncic Z. The cytoplasm as a radiation target: an in silico study of microbeam cell irradiation. Phys Med Biol 2015; 60:2325-37. [PMID: 25715947 DOI: 10.1088/0031-9155/60/6/2325] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We performed in silico microbeam cell irradiation modelling to quantitatively investigate ionisations resulting from soft x-ray and alpha particle microbeams targeting the cytoplasm of a realistic cell model. Our results on the spatial distribution of ionisations show that as x-rays are susceptible to scatter within a cell that can lead to ionisations in the nucleus, soft x-ray microbeams may not be suitable for investigating the DNA damage response to radiation targeting the cytoplasm alone. In contrast, ionisations from an ideal alpha microbeam are tightly confined to the cytoplasm, but a realistic alpha microbeam degrades upon interaction with components upstream of the cellular target. Thus it is difficult to completely rule out a contribution from alpha particle hits to the nucleus when investigating DNA damage response to cytoplasmic irradiation. We find that although the cytoplasm targeting efficiency of an alpha microbeam is better than that of a soft x-ray microbeam (the probability of stray alphas hitting the nucleus is 0.2% compared to 3.6% for x-rays), stray alphas produce more ionisations in the nucleus and thus have greater potential for initiating damage responses therein. Our results suggest that observed biological responses to cytoplasmic irradiation include a small component that can be attributed to stray ionisations in the nucleus resulting from the stochastic nature of particle interactions that cause out-of-beam scatter. This contribution is difficult to isolate experimentally, thus demonstrating the value of the in silico approach.
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Affiliation(s)
- H L Byrne
- Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006, Australia
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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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Alloni D, Campa A, Friedland W, Mariotti L, Ottolenghi A. Integration of Monte Carlo simulations with PFGE experimental data yields constant RBE of 2.3 for DNA double-strand break induction by nitrogen ions between 125 and 225 keV/μm LET. Radiat Res 2013; 179:690-7. [PMID: 23647004 DOI: 10.1667/r3043.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The number of small radiation-induced DNA fragments can be heavily underestimated when determined from measurements of DNA mass fractions by gel electrophoresis, leading to a consequent underestimation of the initial DNA damage induction. In this study we reanalyzed the experimental results for DNA fragmentation and DNA double-strand break (DSB) yields in human fibroblasts irradiated with γ rays and nitrogen ion beams with linear energy transfer (LET) equal to 80, 125, 175 and 225 keV/μm, originally measured by Höglund et al. (Radiat Res 155, 818-825, 2001 and Int J Radiat Biol 76, 539-547, 2000). In that study the authors converted the measured distributions of fragment masses into DNA fragment distributions using mid-range values of the measured fragment length intervals, in particular they assumed fragments with lengths in the interval of 0-48 kbp had the mid-range value of 24 kbp. However, our recent detailed simulations with the Monte Carlo code PARTRAC, while reasonably in agreement with the mass distributions, indicate significantly increased yields of very short fragments by high-LET radiation, so that the actual average fragment lengths, in the interval 0-48 kbp, 2.4 kbp for 225 keV/μm nitrogen ions were much shorter than the assumed mid-range value of 24 kbp. When the measured distributions of fragment masses are converted into fragment distributions using the average fragment lengths calculated by PARTRAC, significantly higher yields of DSB related to short fragments were obtained and resulted in a constant relative biological effectiveness (RBE) for DSB induction yield of 2.3 for nitrogen ions at 125-225 keV/μm LET. The previously reported downward trend of the RBE values over this LET range for DSB induction appears to be an artifact of an inadequate average fragment length in the smallest interval.
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Affiliation(s)
- D Alloni
- Laboratory of Applied Nuclear Energy, Università degli studi di Pavia, Italy
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Mothersill C, Smith RW, Fazzari J, McNeill F, Prestwich W, Seymour CB. Evidence for a physical component to the radiation-induced bystander effect? Int J Radiat Biol 2012; 88:583-91. [DOI: 10.3109/09553002.2012.698366] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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Kundrát P, Friedland W. Non-linear response of cells to signals leads to revised characteristics of bystander effects inferred from their modelling. Int J Radiat Biol 2012; 88:743-50. [DOI: 10.3109/09553002.2012.698029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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