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Matsuya Y, Sato T, Nakamura R, Naijo S, Date H. A theoretical cell-killing model to evaluate oxygen enhancement ratios at DNA damage and cell survival endpoints in radiation therapy. Phys Med Biol 2020; 65:095006. [PMID: 32135526 DOI: 10.1088/1361-6560/ab7d14] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Radio-resistance induced under low oxygen pressure plays an important role in malignant progression in fractionated radiotherapy. For the general approach to predict cell killing under hypoxia, cell-killing models (e.g. the Linear-Quadratic model) have to be fitted to in vitro experimental survival data for both normoxia and hypoxia to obtain the oxygen enhancement ratio (OER). In such a case, model parameters for every oxygen condition needs to be considered by model-fitting approaches. This is inefficient for fractionated irradiation planning. Here, we present an efficient model for fractionated radiotherapy the integrated microdosimetric-kinetic model including cell-cycle distribution and the OER at DNA double-strand break endpoint (OERDSB). The cell survival curves described by this model can reproduce the in vitro experimental survival data for both acute and chronic low oxygen concentrations. The OERDSB used for calculating cell survival agrees well with experimental DSB ratio of normoxia to hypoxia. The important parameters of the model are oxygen pressure and cell-cycle distribution, which enables us to predict cell survival probabilities under chronic hypoxia and chronic anoxia. This work provides biological effective dose (BED) under various oxygen conditions including its uncertainty, which can contribute to creating fractionated regimens for multi-fractionated radiotherapy. If the oxygen concentration in a tumor can be quantified by medical imaging, the present model will make it possible to estimate the cell-killing and BED under hypoxia in more realistic intravital situations.
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Affiliation(s)
- Yusuke Matsuya
- Japan Atomic Energy Agency, Nuclear Science and Engineering Center, Research Group for Radiation Transport Analysis, 2-4 Shirakata, Tokai, Ibaraki 319-1195, Japan. Faculty of Health Sciences, Hokkaido University, Kita-12 Nishi-5, Kita-ku, Sapporo, Hokkaiddo 060-0812, Japan
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Cheng YK, Qin QY, Huang XY, Lan P, Wang L, Gao X, Ma TH. Effect of interval between preoperative radiotherapy and surgery on clinical outcome and radiation proctitis in rectal cancer from FOWARC trial. Cancer Med 2019; 9:912-919. [PMID: 31828956 PMCID: PMC6997091 DOI: 10.1002/cam4.2755] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 10/24/2019] [Accepted: 10/28/2019] [Indexed: 12/20/2022] Open
Abstract
Objective The aim of this study was to evaluate the effect of the interval between CRT and surgery on radiation proctitis, the pathologic response, and postoperative morbidity. Methods This was a cohort study from a phase III, randomized controlled trial (FOWARC study, NCT01211210). Data were retrieved from the leading center of the trial. Patients were divided into the short‐interval (≤7 weeks) group and the long‐interval (>7 weeks) group. The rate of radiation proctitis, pathologic complete regression (pCR) and morbidities were calculated for each group. Multivariate analysis was used to verify the impact of interval on radiation proctitis. Results Surgery was performed in 60 patients after an interval of ≤7 weeks and in 97 patients after an interval of >7 weeks. The two groups according to interval were comparable in terms of baseline demographic and clinicotherapeutic characteristics. Radiation proctitis was identified by imaging in 9 (15.0%) patients in short‐interval group and in 31 (32.0%) patients in long‐interval group (P = .018). Multivariate analysis confirmed the correlation between long interval and radiation proctitis (P = .018). The long interval was significantly associated with longer median operation time compared to the short interval (P = .022). The rates of pCR and postoperative complications were not different between two groups. Conclusions A longer interval after CRT may be associated with higher rate of radiation proctitis and longer operation time. Moreover it did not increase the rate of pCR.
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Affiliation(s)
- Yi-Kan Cheng
- Department of Radiation Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Qi-Yuan Qin
- Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China.,Guangdong Institute of Gastroenterology, Guangzhou, People's Republic of China.,Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Xiao-Yan Huang
- Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China.,Guangdong Institute of Gastroenterology, Guangzhou, People's Republic of China.,Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Ping Lan
- Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China.,Guangdong Institute of Gastroenterology, Guangzhou, People's Republic of China.,Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Lei Wang
- Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China.,Guangdong Institute of Gastroenterology, Guangzhou, People's Republic of China.,Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Xiang Gao
- Department of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Teng-Hui Ma
- Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China.,Guangdong Institute of Gastroenterology, Guangzhou, People's Republic of China.,Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China
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Adhikari S, Mukherjee T. Kinetics of Free Radical Reactions of Some Biologically Important Compounds as Studied by Pulse Radiolysis. PROGRESS IN REACTION KINETICS AND MECHANISM 2019. [DOI: 10.3184/007967401103165307] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Soumyakanti Adhikari
- Radiation Chemistry & Chemical Dynamics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Tulsi Mukherjee
- Radiation Chemistry & Chemical Dynamics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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Forster JC, Douglass MJJ, Phillips WM, Bezak E. Monte Carlo Simulation of the Oxygen Effect in DNA Damage Induction by Ionizing Radiation. Radiat Res 2018; 190:248-261. [PMID: 29953346 DOI: 10.1667/rr15050.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
DNA damage induced by ionizing radiation exposure is enhanced in the presence of oxygen (the "oxygen effect"). Despite its practical importance in radiotherapy, the oxygen effect has largely been excluded from models that predict DNA damage from radiation tracks. A Monte Carlo-based algorithm was developed in MATLAB software to predict DNA damage from physical and chemical tracks through a cell nucleus simulated in Geant4-DNA, taking into account the effects of cellular oxygenation (pO2) on DNA radical chemistry processes. An initial spatial distribution of DNA base and sugar radicals was determined by spatially clustering direct events (that deposited at least 10.79 eV) and hydroxyl radical (•OH) interactions. The oxygen effect was modeled by increasing the efficiency with which sugar radicals from direct-type effects were converted to strand breaks from 0.6 to 1, the efficiency with which sugar radicals from the indirect effect were converted to strand breaks from 0.28 to 1 and the efficiency of base-to-sugar radical transfer from •OH-mediated base radicals from 0 to 0.03 with increasing pO2 from 0 to 760 mmHg. The DNA damage induction algorithm was applied to tracks from electrons, protons and alphas with LET values from 0.2 to 150 keV/μm under different pO2 conditions. The oxygen enhancement ratio for double-strand break induction was 3.0 for low-LET radiation up to approximately 15 keV/μm, after which it gradually decreased to a value of 1.3 at 150 keV/μm. These values were consistent with a range of experimental data published in the literature. The DNA damage yields were verified using experimental data in the literature and results from other theoretical models. The spatial clustering approach developed in this work has low memory requirements and may be suitable for particle tracking simulations with a large number of cells.
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Affiliation(s)
- Jake C Forster
- a Department of Physics, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,b Department of Medical Physics, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia
| | - Michael J J Douglass
- a Department of Physics, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,b Department of Medical Physics, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia
| | - Wendy M Phillips
- a Department of Physics, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,b Department of Medical Physics, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia
| | - Eva Bezak
- a Department of Physics, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,c Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia
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Richardson NA, Gu J, Wang S, Xie Y, Schaefer III HF. DNA Nucleosides and Their Radical Anions: Molecular Structures and Electron Affinities. J Am Chem Soc 2004; 126:4404-11. [PMID: 15053630 DOI: 10.1021/ja030487m] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The deoxyribonucleosides have been studied to determine the properties of combinations of 2-deoxyribose with each of the isolated DNA bases for both neutral and anionic species. We have used a carefully calibrated theoretical method [Chem. Rev. 2002, 102, 231], employing the B3LYP hybrid Hartree-Fock/DFT functional with the DZP++ basis set. Predictions are made of the geometric parameters, adiabatic electron affinities, charge distributions based on natural population analysis, and decomposition enthalpy for the neutral and anionic forms of the four 2'-deoxyribonucleosides in DNA: 2'-deoxyriboadenosine (dA), 2'-deoxyribocytidine (dC), 2'-deoxyriboguanosine (dG), and 2'-deoxyribothymidine (dT). Geometric changes in the anions show that the glycosidic bond exhibits little change with excess charge for the guanosine but significant shortening for the adenosine and for the pyrimidines. The zero-point corrected adiabatic electron affinities in eV for each of the 2'-deoxyribonucleosides are as follows: 0.06, dA; 0.09, dG; 0.33, dC; and 0.44, dT. These values are uniformly greater than those of the corresponding isolated bases (-0.28, A; -0.07, G; 0.03, C; 0.20, T) and the isolated 2-deoxyribose (-0.38) at the same level of theory. The vertical detachment energies of dT and dC are substantial, 0.72 and 0.94 eV, and these anions should be observable. A high VDE, 0.91 eV, is also found for dA but its anion is unlikely to be stable due to the small AEA of 0.06 eV. The high VDE reflects the fact that the molecular structures of the anions and the corresponding neutral species are quite different. Valence character is displayed for the SOMOs of dA, dC, and dT, while some component of diffuse character is visible in the SOMO of dG. Further analysis of electronic changes upon electron attachment include an examination of the NPA charges, which show that in the neutral 2'-deoxyribonucleosides the sum of NPA charges for every base is the same, -0.28 with the sum of 2-deoxyribose charges being positive, +0.28. In the anions, the trend in charge division varies based on the nature of the excess electron in the anions. Thermodynamically, the overall enthalpy change for the reaction of water with the neutral nucleosides to give bases and ribose is approximately zero. The analogous decomposition is exothermic by 8 to 11 kcal mol-1 for the anions, indicating possible challenges for anionic gas-phase nucleoside exploration in the presence of water.
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Affiliation(s)
- Nancy A Richardson
- Pensacola Christian College, Department of Basic Sciences and Engineering, Pensacola, Florida, USA
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Bamatraf MMM, O'Neill P, Rao BSM. Redox Dependence of the Rate of Interaction of Hydroxyl Radical Adducts of DNA Nucleobases with Oxidants: Consequences for DNA Strand Breakage. J Am Chem Soc 1998. [DOI: 10.1021/ja9823161] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Melvin T, Botchway SW, Parker AW, O'Neill P. Induction of Strand Breaks in Single-Stranded Polyribonucleotides and DNA by Photoionization: One Electron Oxidized Nucleobase Radicals as Precursors. J Am Chem Soc 1996. [DOI: 10.1021/ja961722m] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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