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González SJ, Cruz GAS. The Photon-Isoeffective Dose in Boron Neutron Capture Therapy. Radiat Res 2012; 178:609-21. [DOI: 10.1667/rr2944.1] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Cao J, Wells RL, Elkind MM. Enhanced Sensitivity to Neoplastic Transformation by137Cs γ-rays of Cells in the G2-/M-phase Age Interval. Int J Radiat Biol 2009; 62:191-9. [PMID: 1355513 DOI: 10.1080/09553009214552011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
C3H mouse 10T1/2 cells, exposed to low doses of fission-spectrum neutrons, have an enhanced frequency of neoplastic transformation if protracted exposures are used (Hill et al. 1982, 1984a, 1985). To explain this anomaly, a biophysical model was proposed (Elkind 1991a,b) having the following essential features: (1) a narrow age interval exists in the growth cycle of 10T1/2 cells in which cells have high sensitivities to transformation; (2) in the latter age interval, cells are also sensitive to killing; (3) with increasing dose, cells at ages earlier in the growth cycle are progressively delayed from entering the sensitive age window; and (4) with increasing dose, the transformation sensitivity of cells in the sensitive window is not expressed due to increased killing. Protracted low doses result in elevated frequencies because of less killing, and reductions in delays in cell progression. Therefore, transformation-sensitive cells can progress into the sensitive interval to replace those that have progressed out of it. The unique shape and radiobiological properties of cells in and around mitosis, led to the proposal that the sensitive window is mitosis and possible cells just preceding or just following M phase (Elkind 1991a,b). Because of the likelihood that the properties of the cells in a sensitive window would not be evident only when fission-spectrum neutrons are used, this study was undertaken using 137Cs gamma-rays. We have found that late G2- to M-phase 10T1/2 cells have a maximal sensitivity to neoplastic transformation as well as to killing by 137Cs gamma-rays.
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Affiliation(s)
- J Cao
- Department of Radiological Health Sciences, Colorado State University, Fort Collins 80523
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Zölzer F, Streffer C. Relative biological effectiveness of 6 MeV neutrons with respect to cell inactivation and disturbances of the G1 phase. Radiat Res 2008; 169:207-13. [PMID: 18220459 DOI: 10.1667/rr0486.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Accepted: 09/07/2007] [Indexed: 11/03/2022]
Abstract
The relative biological effectiveness (RBE) of neutrons and other types of densely ionizing radiation appears to be close to 1.0 for the induction of strand breaks, but considerably higher RBEs have been found for cellular end points such as colony-forming ability. This may be due to differences in the processing of strand breaks or to the involvement of other lesions whose yields are more dependent on radiation quality. Because cell cycle delays may be of great importance in the processing of DNA damage, we determined the RBE for disturbances of the G1 phase in four different cell types (Be11 melanoma, 4197 squamous cell carcinoma, EA14 glioma, GM6419 fibroblasts) and compared them with the RBE for cell inactivation. The method we used to determine the progress from G1 into S was as follows: Cells were serum-deprived for a number of days and then stimulated to grow with culture medium containing normal amounts of serum. Immediately before the change of medium, cells were exposed to graded doses of either 240 kV X rays or 6 MeV neutrons. At different times afterward, cells were labeled with BrdU and the numbers of active S-phase cells were assessed using two-parameter flow cytometry. For all four cell types, cells started to progress from G1 into S after a few hours. Radiation suppressed this process in all cases, but there were some interesting differences. For Be11 and 4197 cells, the most obvious effect was a delay in G1; the labeling index increased a few hours later in irradiated samples than in controls, and there was no significant effect on the maximum labeling index. For EA14 and GM6419 cells, although smaller doses were used because of greater radiosensitivity, a delay of the entry into S phase was again noticeable, but the most significant effect was a reduction in the maximum percentage of active S-phase cells after stimulation, indicating a permanent or long-term arrest in G1. The RBE for the G1 delay was the same for all four cell types, about 2.8, while the RBE for the G1 arrest varied between 3.2 for the most resistant Be11 cells and 1.7 for the most sensitive GM6419 cells. This trend was similar to that observed for the RBE for cell inactivation. If, as described above, the same number of strand breaks per dose is induced by neutrons and by X rays, the signal transduction cascade translates them into a greater G1 delay in the case of higher LET. This appears to be independent of repair capacity, because it is similar in all cell types we investigated. We therefore assume that a higher lesion density or the presence of other types of lesions is important for this relatively early effect. A G1 arrest, however, is more closely related to the later events leading to cell inactivation, where strand break repair does play a major role, influencing X-ray sensitivity more strongly than sensitivity to neutrons because of a lower repairability of lesions induced by higher-LET radiation.
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Affiliation(s)
- F Zölzer
- Institute of Medical Radiobiology, Medical Faculty, University Duisburg-Essen, Germany.
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Palayoor ST, Humm JL, Atcher RW, Hines JJ, Macklis RM. G2M arrest and apoptosis in murine T lymphoma cells following exposure to 212Bi alpha particle irradiation. Nucl Med Biol 1993; 20:795-805. [PMID: 8401380 DOI: 10.1016/0969-8051(93)90166-r] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Asynchronous exponentially growing EL4 murine T lymphoma cells were exposed either to high LET alpha-radiation from 212Bi-DTPA or to gamma-radiation from a 137Cs source. Radiation-induced cell cycle perturbation was studied by flow cytometry. Alpha irradiation, like gamma, transiently arrested cells in the G2M phase in a dose-dependent manner. The maximum percentages of cells accumulated in G2M 18 h after alpha- and gamma-irradiation were comparable, though the dose-response relationships differed. The "RBE" value for G2M block for alpha- versus gamma-radiation was approx. 4. Electron microscopic studies of the cell samples where a large proportion of cells were arrested in G2M showed subcellular changes in nuclear membrane and the presence of morphologically apoptotic cells. Biochemical analysis of DNA from irradiated cells by agarose gel electrophoresis revealed more extensive DNA fragmentation for alpha- vs gamma-irradiation, even at relatively low total doses. We conclude that the high LET radiation is more efficient in inducing G2M block and apoptosis in EL4 lymphoma cells. The overall radiosensitivity of some high and low grade malignant lymphoma cells to radiation may correlate with these processes. The clinical implications of 212Bi-induced G2M delay may be particularly important for biologically targeted high LET radiopharmaceutical therapy.
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Affiliation(s)
- S T Palayoor
- Joint Center for Radiation Therapy, Harvard Medical School, Boston, MA 02115
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Kataoka Y, Basic I, Perrin J, Grdina DJ. Antimutagenic effects of radioprotector WR-2721 against fission-spectrum neurons and 60Co gamma-rays in mice. Int J Radiat Biol 1992; 61:387-92. [PMID: 1347072 DOI: 10.1080/09553009214551081] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The antimutagenic effects of the radiation protective agent, S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721), were studied against fission-spectrum-neutron- and 60Co-gamma-ray-induced mutagenesis in mice. Mutagenesis at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus was measured 56 days following whole-body irradiation with JANUS neutrons (single doses, 50-150 cGy) or 60Co photons (single doses, 250-750 cGy). Splenic T lymphocytes from B6CF1 mice were grown in round-bottomed 96-microwell culture plates with or without the selective agent 6-thioguanine (6-TG). The mutant frequency, as a result of exposure to neutrons or 60Co photons, increased 100-fold with dose. Doses of 150 cGy neutrons and 750 cGy 60Co photons were equally mutagenic. When animals were injected with WR-2721 at a dose of 400 mg/kg body weight, i.p., 30 min before whole-body irradiation with JANUS neutrons or 60Co photons, mutant frequencies were significantly reduced at all radiation doses (i.e. protection factors of 1.4 and 2.4, respectively). Thus, the aminothiols are effective antimutagens. A novel clinical application of these compounds could be in their use to protect against radiation- and/or chemotherapy-induced genotoxic damage to normal cells.
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Affiliation(s)
- Y Kataoka
- Biological and Medical Research Division, Argonne National Laboratory, IL 60439-4833
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Elkind MM. Enhanced neoplastic transformation due to protracted exposures of fission-spectrum neutrons: biophysical model. Int J Radiat Biol 1991; 59:1467-75, 1477-82. [PMID: 1677390 DOI: 10.1080/09553009114551311] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Grdina DJ, Sigdestad CP, Dale PJ, Perrin JM. The effect of 2-[(aminopropyl)amino] ethanethiol on fission-neutron-induced DNA damage and repair. Br J Cancer 1989; 59:17-21. [PMID: 2667608 PMCID: PMC2246967 DOI: 10.1038/bjc.1989.5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The effect(s) of the radioprotector 2-[(aminopropyl)amino] ethanethiol (WR 1065) on fission-neutron-induced DNA damage and repair in V79 Chinese hamster cells was determined by using a neutral filter elution procedure (pH 7.2). When required, WR1065, at a final working concentration of 4 mM, was added to the culture medium, either 30 min before and during irradiation with fission spectrum neutrons (beam energy of 0.85 MeV) from the JANUS research reactor, or for selected intervals of time following exposure. The frequency of neutron-induced DNA strand breaks as measured by neutral elution as a function of dose equalled that observed for 60Co gamma-ray-induced damage (relative biological effectiveness of one). In contrast to the protective effect exhibited by WR1065 in reducing 60Co-induced DNA damage, WR1065 was ineffective in reducing or protecting against induction of DNA strand breaks by JANUS neutrons. The kinetics of DNA double-strand rejoining were measured following neutron irradiation. In the absence of WR1065, considerable DNA degradation by cellular enzymes was observed. This process was inhibited when WR1065 was present. These results indicate that, under the conditions used, the quality (i.e. nature), rather than quantity, of DNA lesions (measured by neutral elution) formed by neutrons was significantly different from that formed by gamma-rays.
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Affiliation(s)
- D J Grdina
- Biological, Environmental and Medical Research Division, Argonne National Laboratory, IL 60439-4833
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van Vliet J, Bootsma AL, van Peperzeel HA, Schipper J, Wensing CJ. Protective effect of hypoxia in the ram testis during single and split-dose X-irradiation. Radiother Oncol 1988; 13:9-16. [PMID: 3187074 DOI: 10.1016/0167-8140(88)90292-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Spermatogonial stem-cell survival in the ram was studied after single (6 Gy) and split-dose (2 x 3 Gy, interval 21-24 h) X-irradiation both under normal and hypoxic conditions. Hypoxia was induced by inflation of an occluder implanted around the testicular artery. The occluders were inflated about 10 min before irradiation and deflated immediately after. Stem-cell survival was measured at 5 or 7 weeks after irradiation by determination of the Repopulation Index (RI) in histological testis sections. The RI-values after fractionated irradiation were only half those after single dose irradiation. Hypoxia had a protective effect on the stem-cell survival. After split-dose irradiation under hypoxic conditions two times more stem cells survived than under normal oxic conditions; the RI-values increased from 34% (oxic) to 68% (hypoxic). This effect of hypoxia was also found after single dose irradiation where the RI-values increased from 68% (oxic) to 84% (hypoxic). The development of the epithelium in repopulated tubules was also studied. Under hypoxia, a significantly higher fraction of tubules with complete epithelium was found after single (38 vs. 4%) as well as after split-dose irradiation (12 vs. 0%).
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Affiliation(s)
- J van Vliet
- Department of Anatomy, School of Veterinary Medicine, State University Utrecht, The Netherlands
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Elkind MM, Ngo FQ, Hill CK, Jones C. Do lethal mutations influence radiation transformation frequencies? INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1988; 53:849-63. [PMID: 3258854 DOI: 10.1080/09553008814551181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- M M Elkind
- Department of Radiology and Radiation Biology, Colorado State University, Fort Collins 80523
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Streffer C, van Beuningen D. The biological basis for tumour therapy by hyperthermia and radiation. Recent Results Cancer Res 1987; 104:24-70. [PMID: 3296050 DOI: 10.1007/978-3-642-82955-0_2] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Cohen L, Ten Haken RK, Mansell J, Yalavarthi SD, Hendrickson FR, Awschalom M. Tolerance of the human spinal cord to high energy p(66)Be(49) neutrons. Int J Radiat Oncol Biol Phys 1985; 11:743-9. [PMID: 3980271 DOI: 10.1016/0360-3016(85)90306-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The risk of post irradiation myelopathy was evaluated in 76 patients followed for 1-5 years after neutron irradiation of the cervical and thoracic regions. No overt myelopathy was observed. Forty-six patients received doses (central cord dose) in excess of 10 Gy, 9 received doses in excess of 12 Gy, and 5 received doses between 13 and 17 Gy, all without any evidence of spinal cord injury. On careful questioning, a subjective transient neuropathy (a tingling sensation in one extremity) was reported by 6 patients, but this was apparently unrelated to dose. A review of available literature revealed a total of 14 patients with myelopathy, 13 of whom received doses in excess of 13 Gy delivered with relatively low energy neutrons generated by the deuteron + beryllium reaction. It is concluded from these studies that the tolerance limit for the human spinal cord irradiated with high energy [p(66)Be(49)] neutrons is close to 15 Gy, above which the risk of cord injury becomes significant. Central cord doses of 13 Gy or less appear to be well tolerated with little, if any, risk of myelopathy. These conclusions are valid for a treatment time of 4 weeks or more with two or more fractions per week (9 or more fractions). The RBE for the human spinal cord irradiated under the above conditions compared with conventionally fractionated photon therapy does not exceed 4.0.
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Blakely EA, Ngo FQ, Curtis SB, Tobias CA. Heavy-Ion Radiobiology: Cellular Studies. ADVANCES IN RADIATION BIOLOGY 1984. [DOI: 10.1016/b978-0-12-035411-5.50013-7] [Citation(s) in RCA: 140] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Lücke-Huhle C, Hieber L, Wegner RD. Caffeine-mediated release of alpha-radiation-induced G2 arrest increases the yield of chromosome aberrations. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1983; 43:123-32. [PMID: 6600726 DOI: 10.1080/09553008314550131] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Severe and partly irreversible G2 arrest caused by americium-241 alpha-particles in Chinese hamster V79 cells acted as a competing process to the yield of detectable aberrant mitoses at metaphase. With increasing dose of alpha-radiation an increasing fraction of cells was irreversibly arrested in G2 with the consequence of interphase death before the first post-irradiation mitosis. This irreversible G2 arrest (demonstrated by flow cytofluorometry and mitotic indices) could be overcome by adding caffeine 8 hours after irradiation, the time point of maximum G2 arrest (80-90 per cent of all cells). Within 3.5 hours the number of aberrant mitoses increased by this treatment from 54 to 96 per cent and from 65 to 99.9 per cent for doses of 1.75 and 4.38 Gy of alpha-particles, respectively. The aberration frequency per mitotic cell, scored as chromatid and isochromatid breaks, rings, interchanges and dicentrics increased by a factor of about 3 after releasing G2 arrested cells. The frequency distribution of aberrations per cell revealed that, after 4.38 Gy, 58 per cent of the formerly G2-arrested cells had more than five aberrations per cell compared to only 8 per cent without the interaction of caffeine.
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Hill CK, Buonaguro FM, Myers CP, Han A, Elkind MM. Fission-spectrum neutrons at reduced dose rates enhance neoplastic transformation. Nature 1982; 298:67-9. [PMID: 7088163 DOI: 10.1038/298067a0] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Higgins PD, DeLuca PM, Pearson DW, Gould MN. Measurement of o.e.r. and r.b.e. for mono-energetic 2.5 and 14.3 MeV neutrons. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1981; 40:313-9. [PMID: 6974716 DOI: 10.1080/09553008114551241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Abstract
Cell-survival data were collected to determine the survival response of asynchronous CHO cells subjects to radiation and hyperthermia. The irradiation was at room temperature 100 minutes before exposure to hyperthermia at 42 degrees C. The survival response to the combination of these two agents is expressed by means of a survival surface, a three-dimensional concept relating cell survival to heat dose and radiation dose. The survival surface could be approximately described by a survival model comprising three components of cell killing: the unperturbed radiation component, the unperturbed hyperthermia component, and the interaction component. The dependence of the radiation component and the interaction component on radiation quality were investigated by irradiating with either 60Co gamma rays, 250 kV X rays or 14.7 MeV neutrons. An analysis suggests that the interaction component and the radiation component exhibit similar dependencies on radiation quality both for the deposition of damage and the repair or accumulation of that damage.
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Ngo FQ, Utsumi H, Han A, Elkind MM. Sublethal damage repair: is it independent of radiation quality? INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1979; 36:521-30. [PMID: 317500 DOI: 10.1080/09553007914551311] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Utsumi H, Elkind MM. Potentially lethal damage: Qualitative differences between ionizing and non-ionizing radiation and implications for 'single-hit' killing. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1979; 35:373-80. [PMID: 312795 DOI: 10.1080/09553007914550451] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Aspects of OER and RBE Relevant to Neutron Therapy. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/b978-0-12-035408-5.50006-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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