Yuko Kinashi

Kyoto University, Kioto, Kyōto, Japan

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Publications (128)252.13 Total impact

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    ABSTRACT: Conventional therapies for diseases that are associated with protein aggregation typically prevent rather than clear protein aggregates. We have proposed neutron dynamic therapy (NDT) as a physical clearance therapy for protein aggregates. Advanced glycation end-products (AGEs), which are aggregated proteins, have been implicated in diabetes, Alzheimer's, and heart disease. Herein, we report the use of the boron tracedrug UTX-51, under thermal neutron irradiation, as an NDT for the targeted clearance of glycated bovine serum albumin (Gly-BSA), a model of AGEs.
    Anticancer research 08/2014; 34(8):4503-7. · 1.71 Impact Factor
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    ABSTRACT: It is important to measure the microdistribution of 10B in a cell to predict the cell-killing effect of new boron compounds in the field of boron neutron capture therapy. Alpha autoradiography has generally been used to detect the microdistribution of 10B in a cell. Although it has been performed using a reactor-based neutron source, the realization of an accelerator-based thermal neutron irradiation field is anticipated because of its easy installation at any location and stable operation. Therefore, we propose a method using a cyclotron-based epithermal neutron source in combination with a water phantom to produce a thermal neutron irradiation field for alpha autoradiography. This system can supply a uniform thermal neutron field with an intensity of 1.7×109 (cm−2 s−1) and an area of 40 mm in diameter. In this presentation, we give an overview of our proposed system and describe a demonstration test using a mouse liver sample injected with 500 mg/kg of boronophenyl-alanine.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 01/2014; · 1.09 Impact Factor
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    ABSTRACT: Radiation doses during boron neutron capture therapy for body-trunk tumors were estimated for various internal organs, using data from patients treated at Kyoto University Research Reactor Institute. Dose-volume histograms were constructed for tissues of the lung, liver, kidney, pancreas, and bowel. For pleural mesothelioma, the target total dose to the normal lung tissues on the diseased side is 5 Gy-Eq in average for the whole lung. It was confirmed that the dose to the liver should be carefully considered in cases of right lung disease.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 01/2014; · 1.09 Impact Factor
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    ABSTRACT: It is generally said that low LET radiation produce high dose-rate effect, on the other hand, no significant dose rate effect is observed in high LET radiation. Although high LET radiations are produced in BNCT, little is known about dose-rate effect of BNCT. T98G cells, which were tumor cells, were irradiated by neutron mixed beam with BPA. As normal tissue derived cells, Chinese hamster ovary (CHO-K1) cells and DNA double strand breaks (DNA-DSBs) repair deficient cells, xrs5 cells were irradiated by the neutrons (not including BPA). To DNA-DSBs analysis, T98G cells were stained immunochemically with 53BP1 antibody. The number of DNA-DSBs was determined by counting 53BP1 foci. There was no dose-rate effect in xrs5 cells. D0 difference between 4cGy/min and 20cGy/min irradiation were 0.5 and 5.9 at the neutron and gamma-ray irradiation for CHO-K1, and 0.3 at the neutron for T98G cells. D0 difference between 20cGy/min and 80cGy/min irradiation for T98G cells were 1.2 and 0.6 at neutron irradiation plus BPA and gamma-ray. The differences between neutron irradiations at the dose rate in T98G cells were supported by not only the cell viability but also 53BP1 foci assay at 24h following irradiation to monitor DNA-DSBs. Dose-rate effect of BNCT when T98G cells include 20ppm BPA was greater than that of gamma-ray irradiation. Moreover, Dose-rate effect of the neutron beam when CHO-K1 cells did not include BPA was less than that of gamma-ray irradiation These present results may suggest the importance of dose-rate effect for more efficient BNCT and the side effect reduction.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 12/2013; · 1.09 Impact Factor
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    ABSTRACT: We retrospectively review outcomes of applying boron neutron capture therapy (BNCT) to unresectable advanced or recurrent head and neck cancers. Patients who were treated with BNCT for either local recurrent or newly diagnosed unresectable head or neck cancers between December 2001 and September 2007 were included. Clinicopathological characteristics and clinical outcomes were retrieved from hospital records. Either a combination of borocaptate sodium and boronophenylalanine (BPA) or BPA alone were used as boron compounds. In all the treatment cases, the dose constraint was set to deliver a dose <10-12 Gy-eq to the skin or oral mucosa. There was a patient cohort of 62, with a median follow-up of 18.7 months (range, 0.7-40.8). A total of 87 BNCT procedures were performed. The overall response rate was 58% within 6 months after BNCT. The median survival time was 10.1 months from the time of BNCT. The 1- and 2-year overall survival (OS) rates were 43.1% and 24.2%, respectively. The major acute Grade 3 or 4 toxicities were hyperamylasemia (38.6%), fatigue (6.5%), mucositis/stomatitis (9.7%) and pain (9.7%), all of which were manageable. Three patients died of treatment-related toxicity. Three patients experienced carotid artery hemorrhage, two of whom had coexistent infection of the carotid artery. This study confirmed the feasibility of our dose-estimation method and that controlled trials are warranted.
    Journal of Radiation Research 08/2013; · 1.45 Impact Factor
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    ABSTRACT: Since 1990, Boron Neutron Capture Therapy (BNCT) has been used for over 400 cancer patients at the Kyoto University Research Reactor Institute (KURRI). After BNCT, the patients are radioactive and their (24)Na and (38)Cl levels can be detected via a Na-I scintillation counter. This activity is predominantly due to (24)Na, which has a half-life of 14.96 h and thus remains in the body for extended time periods. Radioactive (24)Na is mainly generated from (23)Na in the target tissue that is exposed to the neutron beam in BNCT. The purpose of this study is to evaluate the relationship between the radioactivity of blood (24)Na following BNCT and the absorbed gamma ray dose in the irradiated field. To assess blood (24)Na, 1 ml of peripheral blood was collected from 30 patients immediately after the exposure, and the radioactivity of blood (24)Na was determined using a germanium counter. The activity of (24)Na in the blood correlated with the absorbed gamma ray doses in the irradiated field. For the same absorbed gamma ray dose in the irradiated field, the activity of blood (24)Na was higher in patients with neck or lung tumors than in patients with brain or skin tumors. The reasons for these findings are not readily apparent, but the difference in the blood volume and the ratio of bone to soft tissue in the irradiated field, as well as the dose that leaked through the clinical collimator, may be responsible.
    Journal of Radiation Research 02/2013; · 1.45 Impact Factor
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    ABSTRACT: Understanding the biological effects of neutron mixed-beam irradiation used for boron neutron capture therapy (BNCT) is important in order to improve the efficacy of the therapy and to reduce side effects. In the present study, cell viability and DNA double-strand breaks (DNA-DSBs) were examined in Chinese hamster ovary cells (CHO-K1) and their radiosensitive mutant cells (xrs5, Ku80-deficient), following neutron mixed-beam irradiation for BNCT. Cell viability was significantly impaired in the neutron irradiation groups compared to the reference gamma-ray irradiation group. The relative biological effectiveness for 10% cell survival was 3.3 and 1.2 for CHO-K1 and xrs5 cells, respectively. There were a similar number of 53BP1 foci, indicators of DNA-DSBs, in the neutron mixed-beam and the gamma-ray groups. In addition, the size of the foci did not differ between groups. However, neutron mixed-beam irradiation resulted in foci with different spatial distributions. The foci were more proximal to each other in the neutron mixed-beam groups than the gamma-ray irradiation groups. These findings suggest that neutron beams may induce another type of DNA damage, such as clustered DNA-DSBs, as has been indicated for other high-LET irradiation.
    Journal of Radiation Research 09/2012; · 1.45 Impact Factor
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    ABSTRACT: To evaluate the effects of employing a (10)B-carrier and manipulating intratumour hypoxia on local tumour response and lung metastatic potential in boron neutron capture therapy (BNCT) by measuring the response of intratumour quiescent (Q) cells. B16-BL6 melanoma tumour-bearing C57BL/6 mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells. The tumours received reactor thermal neutron beam irradiation following the administration of a (10)B-carrier [L-para-boronophenylalanine-(10)B (BPA) or sodium mercaptoundecahydrododecaborate-(10)B (BSH)] in combination with an acute hypoxia-releasing agent (nicotinamide) or mild temperature hyperthermia (MTH). Immediately after the irradiation, cells from some tumours were isolated and incubated with a cytokinesis blocker. The responses of the Q and total (P+Q) cell populations were assessed based on the frequency of micronuclei using immunofluorescence staining for BrdU. In other tumour-bearing mice, macroscopic lung metastases were enumerated 17 days after irradiation. BPA-BNCT increased the sensitivity of the total tumour cell population more than BSH-BNCT. However, the sensitivity of Q cells treated with BPA was lower than that of BSH-treated Q cells. With or without a (10)B-carrier, MTH enhanced the sensitivity of the Q cell population. Without irradiation, nicotinamide treatment decreased the number of lung metastases. With irradiation, BPA-BNCT, especially in combination with nicotinamide treatment, showed the potential to reduce the number of metastases more than BSH-BNCT. BSH-BNCT in combination with MTH improves local tumour control, while BPA-BNCT in combination with nicotinamide may reduce the number of lung metastases.
    The British journal of radiology 03/2012; 85(1011):249-58. · 2.11 Impact Factor
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    ABSTRACT: At Kyoto University Research Reactor Institute, clinical studies of around 400 of Boron Neutron Capture Therapy (BNCT) have been performed using research reactor. On the other hand, we have developed cyclotron based epithermal neutron source. To improve the quality of treatment, it is necessary to perform the detection of two dimensional thermal neutron distribution before and during treatment as quality control. Generally, the method of activation using gold foiVwire and germanium semiconductor detector is applied to detection of thermal neutron flux at several positions. However, the activation method using semiconductor detector takes some time to decide the thermal neutron flux. Therefore, we propose the method using multi-wire proportional counter for detection of two dimensional thermal neutron distribution. We constructed the system consisting of multi-wire detection head, multi-channel preamplifier, multi-channel discriminator, centroid calculation circuit, and data acquisition system. Detection efficiency for BNCT irradiation field was evaluated using Am-Be neutron source with moderator for producing thermal neutrons. Furthermore, two dimensional thermal neutron distribution was demonstrably obtained.
    Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2012 IEEE; 01/2012
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    ABSTRACT: Boron neutron capture reaction (BNCR) is based on irradiation of tumors after accumulation of boron compound. 10B captures neutrons and produces an alpha (4He) particle and a recoiled lithium nucleus (7Li). These particles have the characteristics of high linear energy transfer (LET) radiation and have marked biological effects. The purpose of this study is to verify that BNCR will increase cell killing and slow disappearance of repair protein-related foci to a greater extent in DNA repair-deficient cells than in wild-type cells. Chinese hamster ovary (CHO-K1) cells and a DNA double-strand break (DSB) repair deficient mutant derivative, xrs-5 (Ku80 deficient CHO mutant cells), were irradiated by thermal neutrons. The quantity of DNA-DSBs following BNCR was evaluated by measuring the phosphorylation of histone protein H2AX (gamma-H2AX) and 53BP1 foci using immunofluorescence intensity. Two hours after neutron irradiation, the number of gamma-H2AX and 53BP1 foci in the CHO-K1 cells was decreased to 36.5-42.8% of the levels seen 30 min after irradiation. In contrast, two hours after irradiation, foci levels in the xrs-5 cells were 58.4-69.5% of those observed 30 min after irradiation. The number of gamma-H2AX foci in xrs-5 cells at 60-120 min after BNCT correlated with the cell killing effect of BNCR. However, in CHO-K1 cells, the RBE (relative biological effectiveness) estimated by the number of foci following BNCR was increased depending on the repair time and was not always correlated with the RBE of cytotoxicity. Mutant xrs-5 cells show extreme sensitivity to ionizing radiation, because xrs-5 cells lack functional Ku-protein. Our results suggest that the DNA-DSBs induced by BNCR were not well repaired in the Ku80 deficient cells. The RBE following BNCR of radio-sensitive mutant cells was not increased but was lower than that of radio-resistant cells. These results suggest that gamma-ray resistant cells have an advantage over gamma-ray sensitive cells in BNCR.
    Radiation Oncology 09/2011; 6:106. · 2.11 Impact Factor
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    ABSTRACT: A cyclotron-based epithermal neutron source has been developed for boron neutron capture therapy. This system consists of a cyclotron accelerator producing 1.1-mA proton beams with an energy of 30 MeV, a beam transport system coupled with a beryllium neutron production target, and a beam-shaping assembly (BSA) with a neutron collimator. In our previous work, the BSA was optimized to obtain sufficient epithermal neutron fluxes of ~10(9) cm(-2) s(-1) using a Monte Carlo simulation code. In order to validate the simulation results, irradiation tests using multi-foil activation at the surface of a gamma-ray shield located behind the collimator and water phantom experiments using a collimated epithermal neutron beam were performed. It was confirmed experimentally that the intensity of the epithermal neutrons was 1.2×10(9) cm(-2) s(-1).
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 03/2011; 69(12):1642-5. · 1.09 Impact Factor
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    ABSTRACT: Nimustine (ACNU) and temozolomide (TMZ) are DNA alkylating agents which are commonly used in chemotherapy for glioblastomas. ACNU is a DNA cross-linking agent and TMZ is a methylating agent. The therapeutic efficacy of these agents is limited by the development of resistance. In this work, the role of the Fanconi anemia (FA) repair pathway for DNA damage induced by ACNU or TMZ was examined. Cultured mouse embryonic fibroblasts were used: FANCA(-/-), FANCC(-/-), FANCA(-/-)C(-/-), FANCD2(-/-) cells and their parental cells, and Chinese hamster ovary and lung fibroblast cells were used: FANCD1/BRCA2mt, FANCG(-/-) and their parental cells. Cell survival was examined after a 3 h ACNU or TMZ treatment by using colony formation assays. All FA repair pathways were involved in ACNU-induced DNA damage. However, FANCG and FANCD1/BRCA2 played notably important roles in the repair of TMZ-induced DNA damage. The most effective molecular target correlating with cellular sensitivity to both ACNU and TMZ was FANCD1/BRCA2. In addition, it was found that FANCD1/BRCA2 small interference RNA efficiently enhanced cellular sensitivity toward ACNU and TMZ in human glioblastoma A172 cells. These findings suggest that the down-regulation of FANCD1/BRCA2 might be an effective strategy to increase cellular chemo-sensitization towards ACNU and TMZ.
    PLoS ONE 01/2011; 6(5):e19659. · 3.73 Impact Factor
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    ABSTRACT: At Kyoto University Research Reactor Institute, over three hundred clinical trials of Boron Neutron Capture Therapy (BNCT) have been performed using research reactor. On the other hand, we have developed cyclotron based epithermal neutron source. To improve the quality of treatment, it is necessary to perform the detection of two dimensional thermal neutron distribution before treatment as quality control. Generally, the method of activation using gold foil/wire and germanium semiconductor detector is applied to detection of thermal neutron flux at several positions. However, the activation method using semiconductor detector takes some time to decide the thermal neutron flux. Therefore, we propose the method using small scintillator arrays coupled with quartz fibers for easy detection of two dimensional thermal neutron distribution with low radiation damage. To reduce the number of electric circuit and scintillators, we proposed the scanning method using one dimensional scintillation array. To evaluate this method, the irradiation test was performed using Kyoto University Research Reactor(KUR). Two dimensional thermal neutron distribution was easily obtained with the spatial resolution of 5mm.
    01/2011;
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    ABSTRACT: [This corrects the article on p. e19659 in vol. 6.].
    PLoS ONE 01/2011; 6(6). · 3.73 Impact Factor
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    ABSTRACT: Labeling of all proliferating cells in C57BL/6J mice bearing EL4 tumors was achieved by continuous administration of 5-bromo-2'-deoxyuridine (BrdU). Tumors were irradiated with γ rays at a high dose rate or a reduced dose rate at 1 h after the administration of pimonidazole. Assessment of the responses of quiescent and total ( =  proliferating + quiescent) cell populations were based on the frequencies of micronucleation and apoptosis using immunofluorescence staining for BrdU. The response of the pimonidazole-unlabeled tumor cell fractions was assessed by means of apoptosis frequency using immunofluorescence staining for pimonidazole. The total cell fraction that was not labeled with pimonidazole showed significantly enhanced radiosensitivity. However, a significantly greater decrease in radiosensitivity, evaluated using a delayed assay or a decrease in radiation dose rate, was observed in the quiescent cell compared with the total cell population. Overall, the quiescent cell population showed significantly greater radioresistance and capacity to recover from radiation-induced damage than the total tumor cell population. Thus we believe that the subfraction of the quiescent tumor cell population that was not labeled with pimonidazole and that was probably oxygenated is a critical target in the control of solid tumors.
    Radiation Research 10/2010; 174(4):459-66. · 2.70 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the influence of manipulating intratumour oxygenation status and radiation dose rate on local tumour response and lung metastases following radiotherapy, referring to the response of quiescent cell populations within irradiated tumours. B16-BL6 melanoma tumour-bearing C57BL/6 mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells. They received gamma-ray irradiation at high dose rate (HDR) or reduced dose rate (RDR) following treatment with the acute hypoxia-releasing agent nicotinamide or local hyperthermia at mild temperatures (MTH). Immediately after the irradiation, cells from some tumours were isolated and incubated with a cytokinesis blocker. The responses of the quiescent (Q) and total (proliferating + Q) cell populations were assessed based on the frequency of micronuclei using immunofluorescence staining for BrdU. In other tumour-bearing mice, 17 days after irradiation, macroscopic lung metastases were enumerated. Following HDR irradiation, nicotinamide and MTH enhanced the sensitivity of the total and Q-cell populations, respectively. The decrease in sensitivity at RDR irradiation compared with HDR irradiation was slightly inhibited by MTH, especially in Q cells. Without gamma-ray irradiation, nicotinamide treatment tended to reduce the number of lung metastases. With gamma-rays, in combination with nicotinamide or MTH, especially the former, HDR irradiation decreased the number of metastases more remarkably than RDR irradiation. Manipulating both tumour hypoxia and irradiation dose rate have the potential to influence lung metastasis. The combination with the acute hypoxia-releasing agent nicotinamide may be more promising in HDR than RDR irradiation in terms of reducing the number of lung metastases.
    The British journal of radiology 09/2010; 83(993):776-84. · 2.11 Impact Factor
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    ABSTRACT: The aim of this study was to clarify the effect of manipulating intratumor hypoxia on radiosensitivity under reduced dose-rate (RDR) irradiation. Tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells. They received gamma-rays or accelerated carbon-ion beams at high dose-rate (HDR) or RDR with or without tumor clamping to induce hypoxia. Some mice without clamping received nicotinamide, an acute hypoxia-releasing agent or misonidazole, a hypoxic cell radio-sensitizer before irradiation. The responses of quiescent (Q) and total (= P + Q) cells were assessed by the micronucleus frequency using immunofluorescence staining for BrdU. The clearer decrease in radiosensitivity in Q than total cells after RDR gamma-ray irradiation was suppressed with carbon-ion beams, especially with a higher linear energy transfer value. Repressing the decrease in the radiosensitivity under RDR irradiation through keeping tumors hypoxic during irradiation and enhancing the decrease in the radiosensitivity by nicotinamide were clearer with gamma-rays and in total cells than with carbon-ion beams and in Q cells, respectively. Inhibiting the decrease in the radiosensitivity by misonidazole was clearer with gamma-rays and in Q cells than with carbon-ion beams and in total cells, respectively. Manipulating hypoxia during RDR as well as HDR irradiation influences tumor radiosensitivity, especially with gamma-rays.
    Japanese journal of radiology 02/2010; 28(2):132-42. · 0.73 Impact Factor
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    ABSTRACT: This study aimed to assess the effect on solid tumors of mild temperature hyperthermia (MTH) combined with hexamethylenetetramine (HMTA) or tirapazamine (TPZ). Squamous cell carcinoma (SCC VII) tumor-bearing mice were continuously administered 5-bromo-2'-deoxyuridine (BrdU) to label intratumor proliferating (P) cells. Mice received HMTA or TPZ through intraperitoneal single or subcutaneous continuous administration, with or without MTH (40°C, 60 min), followed or not by γ-ray irradiation or cisplatin treatment. After HMTA or TPZ administration without γ-ray irradiation or cisplatin treatment, immediately after γ-ray irradiation, or 1 h after cisplatin treatment, the response of quiescent (Q) cells was assessed in terms of micronucleus frequency using immunofluorescence staining for BrdU. The response of the total (P + Q) tumor cells was determined based on a comparison with non-BrdU-treated tumors. Without MTH, HMTA and TPZ had a nearly equal radiosensitizing and cisplatin sensitivity-enhancing effect on both total and Q cells. With MTH, radio- and cisplatin-sensitizing effects by HMTA were reduced, particularly in the Q cells. In contrast, the enhancing effects of TPZ were increased, particularly in the Q cells. Continuous administration of HMTA and TPZ resulted in higher radio- and cisplatin-sensitizing effects than intraperitoneal single administration. In terms of tumor cytotoxicity as a whole, including Q cells, the administration of γ-ray irradiation or cisplatin treatment combined with continuous HMTA administration is promising, taking into account the clinical use of HMTA. However, MTH should not be combined with HMTA administration.
    Experimental and therapeutic medicine 01/2010; 1(1):169-174. · 0.34 Impact Factor
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    ABSTRACT: At Kyoto University Research Reactor Institute(KURRI), we installed a Cyclotron-Based Epithermal Neutron Source(C-BENS) for Boron Neutron Capture Therapy(BNCT). C-BENS consists of a cyclotron accelerator that can provide a ∼ 1000 μA, 30 MeV proton beam, a neutron production beryllium target and the moderator that can reduce the energy of fast neutrons to an effective energy range. C-BENS can provide epithermal neutron flux of 1.2 × 10 9 (cm−2 s−1) larger than that of conventional reactor-based neutron sources which have been using for clinical trials of BNCT. During irradiation of BNCT, it is important to detect neutron flux up to 109 (cm−2 s−1). Now we have been developing the real-time neutron flux monitor with the characteristics such as the resistance of radiation damage and low attenuation rate in optical fiber. To evaluate detection system, the thermal neutron irradiation field using C-BENS in water phantom with the thermal neutron flux from 108 to 109 was used. The good linearity between the detector counts and thermal neutron flux was obtained.
    IEEE Nuclear Science Symposium conference record. Nuclear Science Symposium 01/2010;
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    ABSTRACT: The radioprotective effects of dimethyl sulfoxide (DMSO) have been known for many years, and the suppression of hydroxyl (OH) radicals induced by ionizing radiation has been thought to be the main cause of this effect. However, the DMSO concentration used was very high, and might be toxic, in earlier studies. In the present study, we administered a lower, non-toxic concentration (0.5%, i.e., 64 mM) of DMSO before irradiation and examined its radioprotective effects. Colony formation assay and micronucleus assay showed significant radioprotective effects in CHO, but not in xrs5, which is defective in the repair function of DNA double-strand breaks. The levels of phosphorylated H2AX and the formation of 53BP1 foci 15 minutes after irradiation, which might reflect initial DNA double-strand breaks, in DMSO-treated CHO cells were similar to those in non-treated cells, suggesting that the radioprotective effects were not attributable to the suppression of general indirect action in the lower concentration of DMSO. On the other hand, 2 hours after irradiation, the average number of 53BP1 foci, which might reflect residual DNA double-strand breaks, was significantly decreased in DMSO-treated CHO cells compared to non-treated cells. The results indicated that low concentration of DMSO exerts radioprotective effects through the facilitation of DNA double-strand break repair rather than through the suppression of indirect action.
    Journal of Radiation Research 01/2010; 51(6):733-40. · 1.45 Impact Factor