Okayama University Medical School Acta Medica Okayama 0386-300X 79 6 2025 Effects of Thoron Inhalation and Cyclosporin A Treatment on Dextran Sulfate Sodium-Induced Oxidative Damage in Mice 421 429 EN Ayumi Tanaka Graduate School of Health Sciences, Okayama University Shota Naoe Graduate School of Health Sciences, Okayama University Reiju Takenaka Graduate School of Health Sciences, Okayama University Norie Kanzaki Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Akihiro Sakoda Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Kiyonori Yamaoka Faculty of Health Sciences, Okayama University Takahiro Kataoka Faculty of Health Sciences, Okayama University Original Article 10.18926/AMO/69844 Radon (222Rn; Rn) and thoron (220Rn; Tn) inhalation have been reported to enhance antioxidant activity in various organs. However, the effects of Tn on the colon have not been investigated. This study aimed to clarify the effects of Tn inhalation, alone and in combination with cyclosporin A (CsA), on dextran sulfate sodium (DSS)-induced colitis, and the accompanying oxidative stress, in mice. Male BALB/c mice were subjected to continuous 8-day Tn inhalation (c-Tn, 533±128 Bq/m3) or alternate-day Tn inhalation over the same period (f-Tn, 577±63Bq/m3), followed by treatment with 3% DSS and either CsA or vehicle for 7 days. Although the disease activity index (DAI) decreased significantly by day 2 in the c-Tn group, scores remained significantly higher than those in the f-Tn group. In the c-Tn group, superoxide dismutase and catalase activity in the colon were significantly elevated compared with those in sham controls. Thus, DSS-induced damage was effectively inhibited in the earlier stages by the c-Tn mode of inhalation than by the f-Tn mode. These findings suggest that continuous Tn inhalation more effectively attenuated early colitis symptoms than alternate-day inhalation, potentially through upregulation of antioxidant defenses. Tn and CsA showed no combined effects. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 78 5 2024 Effect of Radon Inhalation on Murine Brain Proteins: Investigation Using Proteomic and Multivariate Analyses 387 399 EN Shota Naoe Graduate School of Health Sciences, Okayama University Ayumi Tanaka Graduate School of Health Sciences, Okayama University Norie Kanzaki Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Reiju Takenaka Graduate School of Health Sciences, Okayama University Akihiro Sakoda Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Takaaki Miyaji Advanced Science Research Center, Okayama University Kiyonori Yamaoka Faculty of Health Sciences, Okayama University Takahiro Kataoka Faculty of Health Sciences, Okayama University Original Article 10.18926/AMO/67663 Radon is a known risk factor for lung cancer; however, it can be used beneficially, such as in radon therapy. We have previously reported the enhancement of antioxidant effects associated with trace amounts of oxidative stress as one of the positive biological effects of radon inhalation. However, the biological effects of radon inhalation are incompletely understood, and more detailed and comprehensive studies are required. Although several studies have used proteomics to investigate the effects of radon inhalation on body proteins, none has focused on brain proteins. In this study, we evaluated the expression status of proteins in murine brains using proteomic and multivariate analyses to identify those whose expressions changed following two days of radon inhalation at a concentration of 1,500 Bq/m3. We found associations of radon inhalation with the expressions of seven proteins related to neurotransmission and heat shock. These proteins may be proposed as biomarkers indicative of radon inhalation. Although further studies are required to obtain the detailed biological significance of these protein alterations, this study contributes to the elucidation of the biological effects of radon inhalation as a low-dose radiation. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 77 4 2023 Association between Radon Hot Spring Bathing and Health Conditions: A Cross-Sectional Study in Misasa, Japan 387 394 EN Takahiro Kataoka Department of Radiological Technology, Okayama University Graduate School of Health Sciences Hiroshi Habu Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ayumi Tanaka Department of Radiological Technology, Okayama University Graduate School of Health Sciences Shota Naoe Department of Radiological Technology, Okayama University Graduate School of Health Sciences Kaito Murakami Department of Radiological Technology, Okayama University Graduate School of Health Sciences Yuki Fujimoto Department of Radiological Technology, Okayama University Graduate School of Health Sciences Ryohei Yukimine Department of Radiological Technology, Okayama University Graduate School of Health Sciences Soshi Takao Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Fumihiro Mitsunobu Department of Longevity and Social Medicine (Geriatrics), Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takashi Yorifuji Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kiyonori Yamaoka Department of Radiological Technology, Okayama University Graduate School of Health Sciences Original Article 10.18926/AMO/65749 No epidemiological studies have examined the health effects of daily bathing in radon hot springs. In this cross-sectional study, we investigated the associations between radon hot spring bathing and health conditions. The target population was 5,250 adults ≥ 20 years old in the town of Misasa, Japan. We collected information about the participants’ bathing habits and alleviation of a variety of disease symptoms, and their self-rated health (SRH). Unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CI) were calculated. In both the adjusted and unadjusted models of hypertension, significant associations between the > 1×/week hot spring bathing and the alleviation of hypertension symptoms were observed compared to the group whose hot spring bathing was <1×/week: adjusted model, OR 5.40 (95%CI: 1.98-14.74); unadjusted model, 3.67 (1.50-8.99) and for gastroenteritis: adjusted model, 9.18 (1.15-72.96); unadjusted model, 7.62 (1.59-36.49). Compared to the no-bathing group, higher SRH was significantly associated with both bathing < 1×/week: unadjusted model, 2.27 (1.53-3.37) and > 1×/week: adjusted model, 1.91 (1.15-3.19). These findings suggest that bathing in radon hot springs is associated with higher SRH and the alleviation of hypertension and gastroenteritis. No potential conflict of interest relevant to this article was reported.

Oxford University Press Acta Medica Okayama 0449-3060 64 4 2023 Effects of low-dose/high-dose-rate X-irradiation on oxidative stress in organs following forced swim test and its combined effects on alcohol-induced liver damage in mice 635 643 EN Shota Naoe Graduate School of Health Sciences, Okayama University Yuki Fujimoto Graduate School of Health Sciences, Okayama University Kaito Murakami Graduate School of Health Sciences, Okayama University Ryohei Yukimine Graduate School of Health Sciences, Okayama University Ayumi Tanaka Graduate School of Health Sciences, Okayama University Kiyonori Yamaoka Faculty of Health Sciences, Okayama University Takahiro Kataoka Faculty of Health Sciences, Okayama University The liver's susceptibility to oxidative stress after a combination of forced swim test (FST) and low-dose-rate gamma-irradiation has been observed. Therefore, this study aims to clarify the effects of low-dose (0.1 and 0.5 Gy)/high-dose-rate (1.2 Gy/min) irradiation on combined oxidative stressors-liver damage associated with FST and alcohol administration. In addition, the effects of similar irradiation on FST-induced immobility, which induces psychomotor retardation, and antioxidative effects on the brain, lungs, liver and kidneys were investigated, and the results were compared with those of a similar previous study that utilized low-dose-rate irradiation. Low-dose/high-dose-rate (especially 0.5 Gy) irradiation temporarily worsened liver antioxidant function and hepatic function with FST- and alcohol administration-related oxidative damage; however, the damages improved soon after. In addition, the increase in total glutathione content in the liver contributed to the early improvement of hepatic functions. However, pre-irradiation did not suppress immobility during the FST. The results also suggested that the effects of low-dose/high-dose-rate irradiation on the antioxidant functions of each organ after the FST were different from those of low-dose/low-dose-rate irradiation. Overall, this study provides further insights into the effects of low-dose irradiation on exposure to a combination of different oxidative stressors. It will also contribute to the elucidation of dose rate effects on oxidative stress in the low-dose irradiation range. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1660-4601 19 17 2022 Immunomodulatory Effects of Radon Inhalation on Lipopolysaccharide-Induced Inflammation in Mice 10632 EN Takahiro Kataoka Faculty of Health Sciences, Okayama University Shota Naoe Graduate School of Health Sciences, Okayama University Kaito Murakami Graduate School of Health Sciences, Okayama University Yuki Fujimoto Graduate School of Health Sciences, Okayama University Ryohei Yukimine Graduate School of Health Sciences, Okayama University Ayumi Tanaka Graduate School of Health Sciences, Okayama University Kiyonori Yamaoka Faculty of Health Sciences, Okayama University Typical indications for radon therapy include autoimmune diseases such as rheumatoid arthritis (RA). We had previously reported that radon inhalation inhibits Th17 immune responses in RA mice by activating Th1 and Th2 immune responses. However, there are no reports on how radon inhalation affects the activated Th1 and Th17 immune responses, and these findings may be useful for identifying new indications for radon therapy. Therefore, in this study, we investigated the effect of radon inhalation on the lipopolysaccharide (LPS)-induced inflammatory response, focusing on the expression of related cytokines and antioxidant function. Male BALB/c mice were exposed to 2000 Bq/m(3) radon for one day. Immediately after radon inhalation, LPS was administered intraperitoneally at 1.0 mg/kg body weight for 4 h. LPS administration increased the levels of Th1- and Th17-prone cytokines, such as interleukin-2, tumor necrosis factor-alpha, and granulocyte-macrophage colony-stimulating factor, compared to no treatment control (sham). However, these effects were suppressed by radon inhalation. IL-10 levels were significantly increased by LPS administration, with or without radon inhalation, compared to sham. However, radon inhalation did not inhibit oxidative stress induced by LPS administration. These findings suggest that radon inhalation has immunomodulatory but not antioxidative functions in LPS-induced injury. No potential conflict of interest relevant to this article was reported.

Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology. Acta Medica Okayama 0449-3060 2022 Potential inhibitory effects of low-dose thoron inhalation and ascorbic acid administration on alcohol-induced hepatopathy in mice EN Takahiro Kataoka Graduate School of Health Sciences, Okayama University Tsuyoshi Ishida Graduate School of Health Sciences, Okayama University Shota Naoe Graduate School of Health Sciences, Okayama University Norie Kanzaki Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Akihiro Sakoda Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Hiroshi Tanaka Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Fumihiro Mitsunobu Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama University Kiyonori Yamaoka Graduate School of Health Sciences, Okayama University Although thoron inhalation exerts antioxidative effects in several organs, there are no reports on whether it inhibits oxidative stress-induced damage. In this study, we examined the combined effects of thoron inhalation and ascorbic acid (AA) administration on alcohol-induced liver damage. Mice were subjected to thoron inhalation at 500 or 2000 Bq/m(3) and were administered 50% ethanol (alcohol) and 300 mg/kg AA. Results showed that although alcohol administration increased the levels of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) in the serum, the combination of thoron inhalation (500 Bq/m(3)) and AA administration 24 h after alcohol administration effectively inhibited alcohol-induced liver damage. The combination of thoron inhalation (500 Bq/m(3)) and AA administration 24 h after alcohol administration increased catalase (CAT) activity. Alcohol administration significantly decreased glutathione (GSH) levels in the liver. The GSH content in the liver after 2000 Bq/m(3) thoron inhalation was lower than that after 500 Bq/m(3) thoron inhalation. These findings suggest that the combination of thoron inhalation at 500 Bq/m(3) and AA administration has positive effects on the recovery from alcohol-induced liver damage. The results also suggested that thoron inhalation at 500 Bq/m(3) was more effective than that at 2000 Bq/m(3), possibly because of the decrease in GSH content in the liver. In conclusion, the combination of thoron inhalation at 500 Bq/m(3) and AA administration promoted an early recovery from alcohol-induced liver damage. No potential conflict of interest relevant to this article was reported.

The Society for Free Radical Research Japan Acta Medica Okayama 0912-0009 70 2 2022 Confirmation of efficacy, elucidation of mechanism, and new search for indications of radon therapy 87 92 EN Kiyonori Yamaoka Health Sciences, Institute of Academic and Research, Okayama University Takahiro Kataoka Health Sciences, Institute of Academic and Research, Okayama University Indications of radon therapy include various diseases related to respiratory, painful, digestive, chronic degenerative, senile, etc. derived from reactive oxygen species, but most are based on empirical prescriptions. For this reason, we have evaluated the relation between the biological response caused by radon and the tissue/organ absorbed dose more quantitatively, and have promoted the elucidation of mechanisms related to the indication and searching newly. As a result, as a mechanism, a series of moderate physiological stimulative effects accompanying a small amount of oxidative stress by radon inhalation are being elucidated. That is, hyperfunction of anti-oxidation/immune regulation/damage repair, promotion of anti-inflammation/circulating metabolism/hormone secretion, induction of apoptosis/heat shock protein, etc. Also, new indications include inflammatory/neuropathic pain, hepatic/renal injury, colitis, type 1 diabetes, complication kidney injury, hyperuricemia, transient cerebral ischemia, and inflammatory edema. Furthermore, we examined the combined antioxidant effect of radon inhalation and antioxidants or therapeutic agents. As a result, it was clear that any combination treatment could enhance the suppression effect of disease. It can be expected that radon therapy can be used effectively by applying it in addition to usual treatment, since reduction in its dosage can also be expected by concomitant use for drugs with strong side effects. No potential conflict of interest relevant to this article was reported.

The Society for Free Radical Research Japan Acta Medica Okayama 0912-0009 70 2 2022 Mechanisms of action of radon therapy on cytokine levels in normal mice and rheumatoid arthritis mouse model 154 159 EN Takahiro Kataoka Graduate School of Health Sciences, Okayama University Shota Naoe Graduate School of Health Sciences, Okayama University Kaito Murakami Graduate School of Health Sciences, Okayama University Ryohei Yukimine Graduate School of Health Sciences, Okayama University Yuki Fujimoto Graduate School of Health Sciences, Okayama University Norie Kanzaki Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Akihiro Sakoda Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Fumihiro Mitsunobu Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama University Kiyonori Yamaoka Graduate School of Health Sciences, Okayama University The typical indication of radon therapy is rheumatoid arthritis. Although there are several reports that radon therapy has regulation effects on Th17 cells, there has been no study reporting that radon inhalation affects the immune balance among Th1, Th2, and Th17. The purpose of this study is to examine the cytokine changes after radon inhalation. BALB/c mice inhaled radon at 2,000 Bq/m3 for 2 or 4 weeks. SKG/Jcl mice inhaled radon at 2,000 Bq/m3 for 4 weeks after zymosan administration. The results showed that radon inhalation for 4 weeks activated the immune response of Th1, Th2, and Th17. Moreover, the balance among them was not lost by radon inhalation. Radon inhalation for 4 weeks decreased superoxide dismutase activity and increased catalase activity in spleen. These findings suggest that an imbalance of oxidative stress may contribute to activate the immune response. Although zymosan administration activated Th17 immune response and decreased Th1 and Th2 immune response in SKG/Jcl mice, most cytokines related to Th1, Th2, and Th17 approached the normal level by radon inhalation. These findings suggested that radon inhalation has a different action between SKG/Jcl mice and normal BABL/c mice. This may indicate that radon inhalation has an immunomodulation function. No potential conflict of interest relevant to this article was reported.

Oxford University Press Acta Medica Okayama 0449-3060 62 5 2021 Radon inhalation decreases DNA damage induced by oxidative stress in mouse organs via the activation of antioxidative functions 861 867 EN Takahiro Kataoka Graduate School of Health Sciences, Okayama University Hina Shuto Graduate School of Health Sciences, Okayama University Shota Naoe Graduate School of Health Sciences, Okayama University Junki Yano Graduate School of Health Sciences, Okayama University Norie Kanzaki Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Akihiro Sakoda Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Hiroshi Tanaka Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Katsumi Hanamoto Graduate School of Health Sciences, Okayama University Fumihiro Mitsunobu Graduate School ofMedicine Dentistry and Pharmaceutical Sciences, Okayama University Hiroaki Terato Advanced Science Research Center Okayama University Kiyonori Yamaoka Graduate School of Health Sciences, Okayama University Radon inhalation decreases the level of lipid peroxide (LPO); this is attributed to the activation of antioxidative functions. This activation contributes to the beneficial effects of radon therapy, but there are no studies on the risks of radon therapy, such as DNA damage. We evaluated the effect of radon inhalation on DNA damage caused by oxidative stress and explored the underlying mechanisms. Mice were exposed to radon inhalation at concentrations of 2 or 20 kBq/m(3) (for one, three, or 10 days). The 8-hydroxy-2 '-deoxyguanosine (8-OHdG) levels decreased in the brains of mice that inhaled 20 kBq/m(3) radon for three days and in the kidneys of mice that inhaled 2 or 20 kBq/m(3) radon for one, three or 10 days. The 8-OHdG levels in the small intestine decreased by approximately 20-40% (2 kBq/m(3) for three days or 20 kBq/m(3) for one, three or 10 days), but there were no significant differences in the 8-OHdG levels between mice that inhaled a sham treatment and those that inhaled radon. There was no significant change in the levels of 8-oxoguanine DNA glycosylase, which plays an important role in DNA repair. However, the level of Mn-superoxide dismutase (SOD) increased by 15-60% and 15-45% in the small intestine and kidney, respectively, following radon inhalation. These results suggest that Mn-SOD probably plays an important role in the inhibition of oxidative DNA damage. No potential conflict of interest relevant to this article was reported.

Oxford Univ Press Acta Medica Okayama 0449-3060 62 3 2021 Evaluation of the redox state in mouse organs following radon inhalation 390 400 EN Takahiro Kataoka Graduate School of Health Sciences, Okayama University Norie Kanzaki Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Akihiro Sakoda Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Hina Shuto Graduate School of Health Sciences, Okayama University Junki Yano Graduate School of Health Sciences, Okayama University Shota Naoe Graduate School of Health Sciences, Okayama University Hiroshi Tanaka Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Katsumi Hanamoto Graduate School of Health Sciences, Okayama University Hiroaki Terato Advanced Science Research Center, Okayama University Fumihiro Mitsunobu Graduate School ofMedicine Dentistry and Pharmaceutical Sciences, Okayama University Kiyonori Yamaoka Graduate School of Health Sciences, Okayama University Radon inhalation activates antioxidative functions in mouse organs, thereby contributing to inhibition of oxidative stress-induced damage. However, the specific redox state of each organ after radon inhalation has not been reported. Therefore, in this study, we evaluated the redox state of various organs in mice following radon inhalation at concentrations of 2 or 20 kBq/m(3) for 1, 3 or 10 days. Scatter plots were used to evaluate the relationship between antioxidative function and oxidative stress by principal component analysis (PCA) of data from control mice subjected to sham inhalation. The results of principal component (PC) 1 showed that the liver and kidney had high antioxidant capacity; the results of PC2 showed that the brain, pancreas and stomach had low antioxidant capacities and low lipid peroxide (LPO) content, whereas the lungs, heart, small intestine and large intestine had high LPO content but low antioxidant capacities. Furthermore, using the PCA of each obtained cluster, we observed altered correlation coefficients related to glutathione, hydrogen peroxide and LPO for all groups following radon inhalation. Correlation coefficients related to superoxide dismutase in organs with a low antioxidant capacity were also changed. These findings suggested that radon inhalation could alter the redox state in organs; however, its characteristics were dependent on the total antioxidant capacity of the organs as well as the radon concentration and inhalation time. The insights obtained from this study could be useful for developing therapeutic strategies targeting individual organs. No potential conflict of interest relevant to this article was reported.

OXFORD UNIV PRESS Acta Medica Okayama 0449-3060 61 4 2020 X-Irradiation at 0.5 Gy after the forced swim test reduces forced swimming-induced immobility in mice 517 523 EN Takahiro Kataoka Graduate School of Health Sciences, Okayama University Hina Shuto Graduate School of Health Sciences, Okayama University Junki Yano Graduate School of Health Sciences, Okayama University Shota Naoe Graduate School of Health Sciences, Okayama University Tsuyoshi Ishida Graduate School of Health Sciences, Okayama University Tetsuya Nakada Graduate School of Health Sciences, Okayama University Keiko Yamato Laboratory of Neurology and Neurosurgery, National Cerebral and Cardiovascular Center Katsumi Hanamoto Graduate School of Health Sciences, Okayama University Takaharu Nomura Central Research Institute of Electric Power Industry Kiyonori Yamaoka Graduate School of Health Sciences, Okayama University The forced swim test (FST) is a screening model for antidepressant activity; it causes immobility and induces oxidative stress. We previously reported that radon inhalation has antidepressant-like effects in mice potentially through the activation of antioxidative functions upon radon inhalation. This study aimed to investigate the effect of prior and post low-dose X-irradiation (0.1, 0.5, 1.0 and 2.0 Gy) on FST-induced immobility and oxidative stress in the mouse brain, and the differences, if any, between the two. Mice received X-irradiation before or after the FST repeatedly for 5 days. In the post-FST-irradiated group, an additional FST was conducted 4h after the last irradiation. Consequently, animals receiving prior X-irradiation (0.1 Gy) had better mobility outcomes than sham-irradiated mice; however, their levels of lipid peroxide (LPO), an oxidative stress marker, remained unchanged. However, animals that received post-FST X-irradiation (0.5 Gy) had better mobility outcomes and their LPO levels were significantly lower than those of the sham-irradiated mice. The present results indicate that 0.5 Gy X-irradiation after FST inhibits FST-induced immobility and oxidative stress in mice. No potential conflict of interest relevant to this article was reported.

Springer Acta Medica Okayama 0301634X 59 3 2020 Comparison of antioxidative effects between radon and thoron inhalation in mouse organs EN Yusuke Kobashi Graduate School of Health Sciences, Okayama University Takahiro Kataoka Graduate School of Health Sciences, Okayama University Norie Kanzaki Graduate School of Health Sciences, Okayama University Tsuyoshi Ishida Graduate School of Health Sciences, Okayama University Akihiro Sakoda Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Hiroshi Tanaka Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency Yuu Ishimori Prototype Fast Breeder Reactor Monju, Japan Atomic Energy Agency Fumihiro Mitsunobu Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama University Kiyonori Yamaoka Graduate School of Health Sciences, Okayama University Radon therapy has been traditionally performed globally for oxidative stress-related diseases. Many researchers have studied the beneficial effects of radon exposure in living organisms. However, the effects of thoron, a radioisotope of radon, have not been fully examined. In this study, we aimed to compare the biological effects of radon and thoron inhalation on mouse organs with a focus on oxidative stress. Male BALB/c mice were randomly divided into 15 groups: sham inhalation, radon inhalation at a dose of 500 Bq/m3 or 2000 Bq/m3, and thoron inhalation at a dose of 500 Bq/m3 or 2000 Bq/m3 were carried out. Immediately after inhalation, mouse tissues were excised for biochemical assays. The results showed a significant increase in superoxide dismutase and total glutathione, and a significant decrease in lipid peroxide following thoron inhalation under several conditions. Additionally, similar effects were observed for different doses and inhalation times between radon and thoron. Our results suggest that thoron inhalation also exerts antioxidative effects against oxidative stress in organs. However, the inhalation conditions should be carefully analyzed because of the differences in physical characteristics between radon and thoron. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 0962-9351 2012 2012 Inhibitory Effects of Pretreatment with Radon on Acute Alcohol-Induced Hepatopathy in Mice EN Teruaki Toyota Takahiro Kataoka Yuichi Nishiyama Takehito Taguchi Kiyonori Yamaoka We previously reported that radon inhalation activates antioxidative functions in the liver and inhibits carbon tetrachloride-induced hepatopathy in mice. In addition, it has been reported that reactive oxygen species contribute to alcohol-induced hepatopathy. In this study, we examined the inhibitory effects of radon inhalation on acute alcohol- induced hepatopathy in mice. C57BL/6J mice were subjected to intraperitoneal injection of 50% alcohol (5 g/kg bodyweight) after inhaling approximately 4000 Bq/m(3) radon for 24 h. Alcohol administration significantly increased the activities of glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) in serum, and the levels of triglyceride and lipid peroxide in the liver, suggesting acute alcohol- induced hepatopathy. Radon inhalation activated antioxidative functions in the liver. Furthermore, pretreatment with radon inhibited the depression of hepatic functions and antioxidative functions. These findings suggested that radon inhalation activated antioxidative functions in the liver and inhibited acute alcohol- induced hepatopathy in mice. No potential conflict of interest relevant to this article was reported.

Japan Radiation Research Society and Japanese Society for Therapeutic Radiology and Oncology Acta Medica Okayama 0449-3060 53 6 2012 Comparative study on the inhibitory effects of antioxidant vitamins and radon on carbon tetrachloride-induced hepatopathy 830 839 EN Takahiro Kataoka Yuichi Nishiyama Keiko Yamato Junichi Teraoka Yuji Morii Akihiro Sakoda Yuu Ishimori Takehito Taguchi Kiyonori Yamaoka We have previously reported that radon inhalation activates anti-oxidative functions and inhibits carbon tetrachloride (CCl(4))-induced hepatopathy. It has also been reported that antioxidant vitamins can inhibit CCl(4)-induced hepatopathy. In the current study, we examined the comparative efficacy of treatment with radon, ascorbic acid and α-tocopherol on CCl(4)-induced hepatopathy. Mice were subjected to intraperitoneal injection of CCl(4) after inhaling approximately 1000 or 2000 Bq/m(3) radon for 24 h, or immediately after intraperitoneal injection of ascorbic acid (100, 300, or 500 mg/kg bodyweight) or α-tocopherol (100, 300, or 500 mg/kg bodyweight). We estimated the inhibitory effects on CCl(4)-induced hepatopathy based on hepatic function-associated parameters, oxidative damage-associated parameters and histological changes. The results revealed that the therapeutic effects of radon inhalation were almost equivalent to treatment with ascorbic acid at a dose of 500 mg/kg or α-tocopherol at a dose of 300 mg/kg. The activities of superoxide dismutase, catalase, and glutathione peroxidase in the liver were significantly higher in mice exposed to radon than in mice treated with CCl(4) alone. These findings suggest that radon inhalation has an anti-oxidative effect against CCl(4)-induced hepatopathy similar to the anti-oxidative effects of ascorbic acid or α-tocopherol due to the induction of anti-oxidative functions. No potential conflict of interest relevant to this article was reported.

Informa Healthcare Acta Medica Okayama 1525-6049 34 9 2012 Comparative Study on the Inhibitory Effects of α-Tocopherol and Radon on Carbon Tetrachloride-Induced Renal Damage 1181 1187 EN Takahiro Kataoka Keiko Yamato Yuichi Nishiyama Yuji Morii Reo Etani Yuji Takata Katsumi Hanamoto Atsuishi Kawabe Akihiro Sakoda Yuu Ishimori Takehito Taguchi Kiyonori Yamaoka Since the 2011 nuclear accident in Fukushima, the effects of low-dose irradiation, especially internal exposure, are at the forefront of everyone’s attention. However, low-dose radiation induced various stimulating effects such as activation of antioxidative and immune functions. In this study, we attempted to evaluate the quantitative effects of the activation of antioxidative activities in kidney induced by radon inhalation on carbon tetrachloride (CCl₄)-induced renal damage. Mice were subjected to intraperitoneal (i.p.) injection of CCl₄ after inhaling approximately 1000 or 2000 Bq/m³ radon for 24 h, or immediately after i.p. injection of α-tocopherol (100, 300, or 500 mg/kg bodyweight). In case of renal function, radon inhalation at a concentration of 2000 Bq/m³ has the inhibitory effects similar to α-tocopherol treatment at a dose of 300–500 mg/kg bodyweight. The activities of superoxide dismutase and catalase in kidneys were significantly higher in mice exposed to radon as compared to mice treated with CCl₄ alone. These findings suggest that radon inhalation has an antioxidative effect against CCl₄-induced renal damage similar to the antioxidative effects of α-tocopherol due to induction of antioxidative functions. No potential conflict of interest relevant to this article was reported.

Japan Radioisotope Association Acta Medica Okayama 0033-8303 61 1 2012 ラドン吸入がペットの健康改善に及ぼす効果に関する基礎的検討 1 8 EN Takahiro Kataoka Rikizo Tokunaga Akihiro Sakoda Atsushi Kawabe Katsumi Hanamoto Kiyonori Yamaoka 著者らは今までに，共同開発したラドン吸入装置を用いマウスにラドン吸入をさせた場合，諸臓器中の抗酸化機能が亢進する可能性などを明らかにしてきた。本研究では，ラドン吸入の獣医療への応用の可能性について新たに検討するため，健常なイヌ5頭(オス：2(1，9才)，メス：3(1〜5才))及び慢性腎不全症のネコ8頭(オス：3(2〜6才)，メス：5(5〜7才))を対象に基礎的な検討をした。すなわち，約5500Bq/m³のラドンを1回30分で隔日に30日間(計15回)それぞれ吸入させた。その結果，イヌにおいて，中性脂肪が減少する可能性が示された。また，その効果は吸入開始20〜30日後に現れることも示唆できた。他方，ネコにおいて，飲水量が改善し血清中クレアチニンが基準値内に減少する症例がみられるなど，慢性腎不全症に対し一定の効果が期待できる可能性が示唆された。 No potential conflict of interest relevant to this article was reported.

Japan Radioisotope Association Acta Medica Okayama 0033-8303 57 4 2008 ラドン吸入試作装置によるマウス諸臓器中の抗酸化機能の亢進に関する研究 241 251 EN Shinya Nakagawa Takahiro Kataoka Akihiro Sakoda Yuu Ishimori Katsumi Hanamoto Kiyonori Yamaoka ラドン療法の適応症には活性酸素に由来する生活習慣病が多く，その機構の更なる解明が期待されている。また，汎用性があり医学的効果が再現できるラドン吸入装置の構築は意義が大きい。このため，著者らは共同で開発したラドン吸入試作装置を用い，マウス諸臓器中の抗酸化機能の変化特性を検討した。ラドン吸入試作装置は，特殊加工したラドン線源を収納したユニットの数量，それへの送風量及び湿度などを調節することによりラドン濃度を自在に調整可能にするものである。この装置によりマウスに400Bq/m³あるいは4000Bq/m³のラドンを吸入させた。その結果，脳・肺・肝臓・腎臓において，抗酸化系酵素であるSODとカタラーゼの両活性が増加し，過酸化脂質量が減少した。この抗酸化機能の亢進により，本実験条件でのラドン吸入は活性酸素障害の抑制，すなわち，生活習慣病の予防や症状緩和に効果のある可能性が改めて示唆できた。 No potential conflict of interest relevant to this article was reported.

Japan Radioisotope Association Acta Medica Okayama 0033-8303 61 5 2012 Inhibitory Effects of Pre and Post Radon Inhalation on Carbon Tetrachloride-induced Oxidative Damage in Mouse Organs 231 241 EN Yuichi Nishiyama Takahiro Kataoka Junichi Teraoka Akihiro Sakoda Yuu Ishimori Kiyonori Yamaoka Radon inhalation activates antioxidative functions in some organs of mice. We examined the prevention effects of pre radon inhalation and the alleviation effects of post radon inhalation on carbon tetrachloride (CCl₄)-induced oxidative damage in the brain, heart, lung, liver, and kidney of mice. In addition, we compared the effect of pre and post radon inhalation on oxidative damage. Mice inhaled radon at a concentration of 18000Bq/m³ for 6hrs before or after CCl₄ administration. As a result, the total glutathione(t-GSH) contents and catalase(CAT) activities in the brain, heart, lung, liver, and kidney and superoxide dismutase(SOD) activities in the heart and lung were significantly higher in pre and post radon-inhaled mice than in mice treated with only CCl₄. Pre radon inhalation inhibited and post radon inhalation reduced lipid peroxidation induced by CCl₄. In addition, there were no significant differences in lipid peroxide(LPO) levels in the brain, heart, lung, liver, and kidney between pre and post radon-inhaled mice. These findings suggested that post radon inhalation has the same effects as pre radon inhalation against CCl₄-induced oxidative damage in the brain, heart, lung, liver, and kidney. No potential conflict of interest relevant to this article was reported.

Oxford University Press Acta Medica Okayama 0144-8420 146 1-3 2011 Studies on possibility for alleviation of lifestyle diseases by low-dose irradiation or radon inhalation 360 363 EN Takahiro Kataoka Akihiro Sakoda Masaaki Yoshimoto Shinya Nakagawa Teruaki Toyota Yuichi Nishiyama Keiko Yamato Yuu Ishimori Atsushi Kawabe Katsumi Hanamoto Takehito Taguchi Kiyonori Yamaoka Our previous studies showed the possibility that activation of the antioxidative function alleviates various oxidative damages, which are related to lifestyle diseases. Results showed that, low-dose X-ray irradiation activated superoxide dismutase and inhibits oedema following ischaemia-reperfusion. To alleviate ischaemia-reperfusion injury with transplantation, the changes of the antioxidative function in liver graft using low-dose X-ray irradiation immediately after exenteration were examined. Results showed that liver grafts activate the antioxidative function as a result of irradiation. In addition, radon inhalation enhances the antioxidative function in some organs, and alleviates alcohol-induced oxidative damage of mouse liver. Moreover, in order to determine the most effective condition of radon inhalation, mice inhaled radon before or after carbon tetrachloride (CCl₄) administration. Results showed that radon inhalation alleviates CCl₄-induced hepatopathy, especially prior inhalation. It is highly possible that adequate activation of antioxidative functions induced by low-dose irradiation can contribute to preventing or reducing oxidative damages, which are related to lifestyle diseases. No potential conflict of interest relevant to this article was reported.

The Editorial Secretariat of JCBN Acta Medica Okayama 0912-0009 45 2 2009 Basic Study on Active Changes in Biological Function of Mouse Liver Graft in Cold Storage after Low-Dose X-Irradiation 219 226 EN Takahiro Kataoka Masaaki Yoshimoto Shinya Nakagawa Yuko Mizuguchi Takehito Taguchi Kiyonori Yamaoka We previously reported that low-dose X-irradiation alleviates ischemia-reperfusion injury such as mouse paw edema. In this study, we examined active changes in the biological function of mouse liver grafts in cold storage after low-dose X-irradiation. Mouse livers were sham-irradiated or were irradiated with 0.25, 0.5, 1.0, or 5.0 Gy of X-ray and stored for 4, 8, 24, or 48 h in preservation or saline solution. The results show that storage for 24 h in saline solution after 0.5 Gy irradiation significantly increased the activity of superoxide dismutase (SOD) and catalase. Following storage for 4, 8, or 48 h in preservation solution, lipid peroxide levels of the 0.5 Gy irradiated group were significantly lower than those of the sham irradiated group. Following storage for 24 h in preservation solution, the activity of SOD and catalase of the 1.0 Gy irradiated group were significantly higher than those of the sham irradiated group. Hepatocytes stored in saline solution were vacuolated. However, no vacuole formation was observed in hepatocytes stored in preservation solution. These findings suggest that low-dose irradiation significantly activates antioxidative functions of liver grafts. Moreover, the dose at which enhancement of antioxidative function occurs in livers stored in preservation solution, which contains glutathione, is significantly higher than that in saline solution. No potential conflict of interest relevant to this article was reported.

The Editorial Secretariat of JCBN Acta Medica Okayama 0912-0009 43 1 2008 No Different Sensitivity in Terms of Whole-Body Irradiation between Normal and Acatalasemic Mice 41 49 EN Shinya Nakagawa Takahiro Kataoka Yuko Mizuguchi Masaaki Yoshimoto Akihiro Sakoda Takaharu Nomura Da-Hong Wang Atsushi Kawabe Takehito Taguchi Kiyonori Yamaoka To elucidate the radiosensitivity of an acatalasemic mouse, we examined the time and dose-dependency in the survival rates, the lymphocytes and the intestinal epithelial cells, and the antioxidant function after 3.0 to 12.0 Gy whole body irradiation. Results showed that no significant differences between acatalasemic mice and normal mice were observed in the survival rates and the histological changes in spleens and small intestine after each irradiation. The catalase activities in livers and spleens of acatalasemic mice were significantly lower than those of normal mice and the glutathione peroxidase activity in livers of acatalasemic mice was significantly higher than that of normal mice. At 10 days after 6.0 Gy irradiation, the catalase activities in livers of acatalasemic and normal mice and that in spleens of normal mice significantly decreased compared with no-irradiation control, and there were no differences between those catalase activities. The total glutathione content in acatalasemic mice was significantly higher than that in normal mice at 10 days after 6.0 Gy irradiation. These findings suggested that the radiosensitivity of acatalasemic mice in terms of whole body irradiation doesn’t significantly differ from that of normal mice, probably due to compensated sufficient contents of glutathione peroxidase and total glutathione in acatalasemic mice. No potential conflict of interest relevant to this article was reported.

Hindawi Publishing Corporation Acta Medica Okayama 2012 2012 Activation of Biodefense System by Low-Dose Irradiation or Radon Inhalation and Its Applicable Possibility for Treatment of Diabetes and Hepatopathy 11 11 EN Takahiro Kataoka Kiyonori Yamaoka Adequate oxygen stress induced by low-dose irradiation activates biodefense system, such as induction of the synthesis of superoxide dismutase (SOD) and glutathione peroxidase. We studied the possibility for alleviation of oxidative damage, such as diabetes and nonalcoholic liver disease. Results show that low-dose γ-irradiation increases SOD activity and protects against alloxan diabetes. Prior or post-low-dose X- or γ-irradiation increases antioxidative functions in livers and inhibits ferric nitrilotriacetate and carbon tetrachloride-induced (CCl₄) hepatopathy. Moreover, radon inhalation also inhibits CCl₄-induced hepatopathy. It is highly possible that low-dose irradiation including radon inhalation activates the biodefence systems and, therefore, contributes to preventing or reducing reactive oxygen species-related diabetes and nonalcoholic liver disease, which are thought to involve peroxidation. No potential conflict of interest relevant to this article was reported.

Journal of Radiation Research Editorial Committee Acta Medica Okayama 0449-3060 48 6 2007 Inhibitory Effects of Prior Low-dose X-irradiation on Ischemia-reperfusion Injury in Mouse Paw 505 513 EN Takahiro Kataoka Yuko Mizuguchi Masaaki Yoshimoto Takehito Taguchi Kiyonori Yamaoka We have reported that low-dose, unlike high-dose, irradiation enhanced antioxidation function and reduced oxidative damage. On the other hand, ischemia-reperfusion injury is induced by reactive oxygen species. In this study, we examined the inhibitory effects of prior low-dose X-irradiation on ischemia-reperfusion injury in mouse paw. BALB/c mice were irradiated by sham or 0.5 Gy of X-ray. At 4 hrs after irradiation, the left hind leg was bound 10 times with a rubber ring for 0.5, 1, or 2 hrs and the paw thickness was measured. Results show that the paw swelling thickness by ischemia for 0.5 hr was lower than that for 2 hrs. At 1 hr after reperfusion from ischemia for 1 hr, superoxide dismutase activity in serum was increased in those mice which received 0.5 Gy irradiation and in the case of the ischemia for 0.5 or 1 hr, the paw swelling thicknesses were inhibited by 0.5 Gy irradiation. In addition, interstitial edema in those mice which received 0.5 Gy irradiation was less than that in the mice which underwent by sham irradiation. These findings suggest that the ischemia-reperfusion injury is inhibited by the enhancement of antioxidation function by 0.5 Gy irradiation. No potential conflict of interest relevant to this article was reported.

Journal of Radiation Research Editorial Committee Acta Medica Okayama 0449-3060 46 1 2005 The Elevation of p53 Protein Level and SOD Activity in the Resident Blood of the Misasa Radon Hot Spring District 21 24 EN Kiyonori Yamaoka Fumihiro Mitsunobu Shuji Kojima Misako Shibakura Takahiro Kataoka Katsumi Hanamoto Yoshiro Tanizaki To clarify the mechanism by which radon hot springs prevent cancer or not, in this study, blood was collected from residents in the Misasa hot spring district and in a control district. The level of a representative cancer-suppressive gene, p53, and the activity of a representative antioxidant enzyme, superoxide dismutase (SOD), were analyzed as indices. The level of serum p53 protein in the males in the Misasa hot spring district was found to be 2-fold higher than that in the control district, which is a significant difference. In the females in the Misasa hot spring district, SOD activity was approximately 15% higher than that in the control district, which is also statistically significant, and exceeded the reference range of SOD activity despite advanced age. These results suggested that routine exposure of the residents in the Misasa hot spring district to radon at a concentration about 3 times higher than the national mean induces trace active oxygen in vivo, potentiating products of cancer-suppressive gene and antioxidant function. As the p53 protein level was high in the residents in the Misasa hot spring district, apoptosis of cancer cells may readily occur. No potential conflict of interest relevant to this article was reported.

Journal of Radiation Research Editorial Committee Acta Medica Okayama 0449-3060 45 1 2004 Inhibitory Effects of Prior Low-dose X-ray Irradiation on Carbon Tetrachloride-induced Hepatopathy in Acatalasemic Mice 89 95 EN Kiyonori Yamaoka Takahiro Kataoka Takaharu Nomura Takehito Taguchi Da-Hong Wang Shuji Mori Katsumi Hanamoto Shohei Kira The catalase activities in blood and organs of the acatalasemic (C3H/AnLCs^bCs^b) mouse of C3H strain are lower than those of the normal (C3H/AnLCs^aCs^a) mouse. We examined the effects of prior low-dose (0.5 Gy) X-ray irradiation, which reduced the oxidative damage under carbon tetrachloride-induced hepatopathy in the acatalasemic or normal mice. The acatalasemic mice showed a significantly lower catalase activity and a significantly higher glutathione peroxidase activity compared with those in the normal mice. Moreover, low-dose irradiation increased the catalase activity in the acatalasemic mouse liver to a level similar to that of the normal mouse liver. Pathological examinations and analyses of blood glutamic oxaloacetic and glutamic pyruvic transaminase activity and lipid peroxide levels showed that carbon tetrachloride induced hepatopathy was inhibited by low-dose irradiation. These findings may indicate that the free radical reaction induced by the lack of catalase and the administration of carbon tetrachloride is more properly neutralized by high glutathione peroxidase activity and low-dose irradiation in the acatalasemic mouse liver. No potential conflict of interest relevant to this article was reported.

Journal of Radiation Research Editorial Committee Acta Medica Okayama 0449-3060 52 6 2011 Study of the Response of Superoxide Dismutase in Mouse Organs to Radon Using a New Large-scale Facility for Exposing Small Animals to Radon 775 781 EN Takahiro Kataoka Akihiro Sakoda Yuu Ishimori Teruaki Toyota Yuichi Nishiyama Hiroshi Tanaka Fumihiro Mitsunobu Kiyonori Yamaoka We examined dose–dependent or dose rate–dependent changes of superoxide dismutase (SOD) activity using a new large-scale facility for exposing small animals to radon. Mice were exposed to radon at a concentration of 250, 500, 1000, 2000, or 4000 Bq/m³ for 0.5, 1, 2, 4, or 8 days. When mice were exposed to radon at 2000 day•Bq/m³, activation of SOD activities in plasma, liver, pancreas, heart, thymus, and kidney showed dose–rate effects. Our results also suggested that continuous exposure to radon increased SOD activity, but SOD activity transiently returned to normal levels at around 2 days. Moreover, we classified the organs into four groups (1. plasma, brain, lung; 2. heart, liver, pancreas, small intestine; 3. kidney, thymus; 4. stomach) based on changes in SOD activity. Thymus had the highest responsiveness and stomach had lowest. These data provide useful baseline measurements for future studies on radon effects. No potential conflict of interest relevant to this article was reported.

Springer Science+Business Media, LLC Acta Medica Okayama 0360-3997 35 2 2012 Protective Effects of Radon Inhalation on Carrageenan-Induced Inflammatory Paw Edema in Mice 713 722 EN Takahiro Kataoka Junichi Teraoka Akihiro Sakoda Yuichi Nishiyama Keiko Yamato Mayuko Monden Yuu Ishimori Takaharu Nomura Takehito Taguchi Kiyonori Yamaoka We assessed whether radon inhalation inhibited carrageenan-induced inflammation in mice. Carrageenan (1% v/v) was injected subcutaneously into paws of mice that had or had not inhaled approximately 2,000 Bq/m³ of radon for 24 h. Radon inhalation significantly increased superoxide dismutase (SOD) and catalase activities and significantly decreased lipid peroxide levels in mouse paws, indicating that radon inhalation activates antioxidative functions. Carrageenan administration induced paw edema and significantly increased tumor necrosis factor-alpha (TNF-α) and nitric oxide in serum. However, radon inhalation significantly reduced carrageenan-induced paw edema. Serum TNF-α levels were lower in the radon-treated mice than in sham-treated mice. In addition, SOD and catalase activities in paws were significantly higher in the radon-treated mice than in the sham-treated mice. These findings indicated that radon inhalation had anti-inflammatory effects and inhibited carrageenan-induced inflammatory paw edema. No potential conflict of interest relevant to this article was reported.

Springer Science+Business Media, LLC Acta Medica Okayama 0360-3997 34 6 2011 Radon Inhalation Protects Mice from Carbon-Tetrachloride-Induced Hepatic and Renal Damage 559 567 EN Takahiro Kataoka Yuichi Nishiyama Teruaki Toyota Masaaki Yoshimoto Akihiro Sakoda Yuu Ishimori Yutaka Aoyama Takehito Taguchi Kiyonori Yamaoka No potential conflict of interest relevant to this article was reported.

Springer Science+Business Media, LLC Acta Medica Okayama 0360-3997 35 1 2012 Inhibitory Effects of Prior Low-dose X-irradiation on Cold-induced Brain Injury in Mouse 89 97 EN Masaaki Yoshimoto Takahiro Kataoka Teruaki Toyota Takehito Taguchi Kiyonori Yamaoka We examined the inhibitory effects of low-dose X-irradiation on mouse brain tissue with cold-induced injury by comparing tissue samples from three groups of mice: control, sham-irradiated cold-exposed, and X-ray-irradiated (0.5 Gy) cold-exposed mice. The water content in brain increased significantly in the sham-irradiated group following the cold-induced injury relative to the control group. However, water content in brain tissue from the X-ray-irradiated group was significantly lower than that from the sham-irradiated group. Levels of antioxidants, such as superoxide dismutase and glutathione, in brain tissue from the X-ray-irradiated group were higher than those from the sham-irradiated group. Moreover, the cold injury-induced cell death, particularly apoptosis, while low-dose irradiation inhibited cell death, especially among glial cells, but not numeral cells. These findings suggest that prior low-dose X-irradiation activated antioxidant function and inhibited cold-induced brain injury. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 65 2 2011 An Assessment of Radioactivity Levels of 210Pb and 40K in Tobacco and Radiation Exposure from Smoking 91 95 EN Tomohiro Nagamatsu Akihiro Sakoda Takahiro Kataoka Toshiro Ono Kiyonori Yamaoka Original Article 10.18926/AMO/45267 No research has been conducted on the radiation influence of tobacco on the alimentary system, although there have been some previous works on the respiratory system. In this study, the radioactive concentrations of 210Pb and 40K in a cigarette sample were first measured. The transfer factors of the nuclides from tobacco into smoke and solution (saliva and/or alcohol) were then examined. Moreover, the radiation doses from smoke inhalation were also evaluated. The radioactive concentrations of 210Pb and 40K in the cigarette tobacco were 0.01 and 0.3 Bq/cigarette. Since this 210Pb activity and the 210Po activity previously reported for the same sample were comparable, it can be concluded that there was a radioactive equilibrium between the 2 nuclides. The observed transfer factor of 210Pb (12%) into smoke was almost the same as that of 40K (15%), whereas the reported value for 210Po (60%) was significantly higher. The radiation doses due to inhalation of cigarette smoke varied from organ to organ, depending on the organotropic properties of the nuclide. For example, the kidneys, respiratory tract, and spleen showed relatively high doses from 210Pb and 210Po. The leaching rates indicated an inconsistent tendency related to solution types. This result could suggest that alcohol drinking, which is common in smokers, does not especially enhance the leaching characteristics. No potential conflict of interest relevant to this article was reported.

Elsevier Ltd. Acta Medica Okayama 0969-8043 66 5 2008 Radioactivity and radon emanation fraction of the granites sampled at Misasa and Badgastein 648 652 EN Akihiro Sakoda Katsumi Hanamoto Yu Ishimori Tomohiro Nagamatsu Kiyonori Yamaoka The chemical composition was analyzed and the radioactivity, radon exhalation rate and emanation fraction were measured to investigate the characteristics of the granites sampled at Misasa and Badgastein, world famous for radon therapy. The Misasa granite was probably composed of quartz, albite and microcline. The Badgastein granite was probably composed of quartz and muscovite. The radon exhalation rates and emanation fractions of the Misasa granite were much higher than those of the Badgastein granite, regardless of the Ra-226 activity concentrations. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 43 1 2008 Effects of some physical conditions on leaching rate of radon from radioactive minerals originating from some hot springs 106 110 EN Akihiro Sakoda Katsumi Hanamoto Yuu Ishimori Tomohiro Nagamatsu Kiyonori Yamaoka <p>In order to determine the best physical conditions for leaching more radon from minerals into water, we measured the leaching rate of radon from radioactive minerals under the conditions of some different grain sizes and water temperatures. Water temperature affected the leaching rate of radon although the grain size did not significantly affect it. Furthermore, we proposed ultrasonic irradiation to the mixture of a mineral and water as the method of leaching more radon. Ultrasonic irradiation was efficient to leach more radon from the mineral soaked in water because of ultrasonic cavitation.</p> No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 12 1 2001 看護の視点からのアメニティ創出への試み ―ラッピング技法を用いてのアプローチから― 27 36 EN Kiyomi Ono Yuko Hayashi Nobuko Ohi Hiroyuki Okuda Kiyonori Yamaoka 10.18926/15240 病院におけるアメニティの重要性は十数年前から言われているが,それは建物の建築の時だけでなく,その後療養の場所をどのように維持し,快適環境を患者にいつまでも提供していくかである｡これまで日常の看護業務において掲示物やパンフレットの置き方,床頭台のあり方などは整理整頓の一環で病棟管理の中にあった｡だが,もう一つの流れがある｡ウイリアム・モリスは生活の中における芸術化を考え,生活用品そのものに美しきと手作りの良さがあることを提唱した｡こうした生活デザインの流れの中で,本研究では本学科棟内において床頭台のディスプレイや掲示の仕方,パンフレットの置き方など,ラッピング技法を使用し,入院生活上のアメニティの創出を試みた｡その後,ラッピング技法を用いたアメニティ創出の試みは患者の心を癒す可能性のあることを明らかにした｡また,ラッピング技法使用上の留意点についても指摘した｡ No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 12 1 2001 欧州におけるラドン療法の医学的研究に関する最近の動向 7 13 EN Kiyonori Yamaoka Takashi Mifune 10.18926/15237 本総説は,本邦で実施している三朝ラドン温泉の適応症に関する機構解明に資するために調査した欧州におけるラドン療法の医学的研究に関する最近の動向の概要についてまとめたものである｡すなわち,ラドンを用いた温泉や坑道での療法の適応症には,脊椎の非細菌性炎症(べヒテレフ病),慢性多発性関節炎,気管支喘息などが含まれる｡臨床医学的研究として,以前,客観的方法で検討されたものはほとんどなかったが,最近,無作為化二重盲検臨床試験などにより,ラドン療法がベヒテレフ病,慢性多発性関節炎などの患者の痛みを緩和させる効能があることが実証されつつある｡また,基礎医学的研究として,抗酸化機能や免疫機能などの指標に着目した動物実験により,ラドン療法の機構を解明する上で合理的根拠が得られつつあることもわかった｡さらに,これらの知見と本邦での研究動向を踏まえ,今後,期待されるラドン療法の機構解明を行うための研究課題を提案した｡ No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 13 1 2002 低線量放射線の適応応答に関する最近の研究動向とその意義 7 15 EN Toshimasa Kusuhara Katsumi Hanamoto Kiyonori Yamaoka 10.18926/15221 本総説は,低線量放射線に対する生体の適応応答(以下,適応応答)に関してその効果を含む最近の研究動向,さらに放射線防護との関係についてまとめたものである｡特にこの分野で最も検討が進んでいる｢低線量放射線照射の生物学的影響｣に関する国際研究組織(BELLE)での動向を中心に報告するものである｡即ち,ヒトと自然放射線との共存などヒトの生活環境と適応応答について,適応応答の短期的･長期的効果など適応応答の効果とその生物学的意義について言及した｡次に,適応応答の医療などへの応用の可能性について,また,適応応答と放射線防護との関係についても言及した｡ここで,低線量放射線にはヒトへの有益な効果があるとの多くの報告例がある半面,放射線防護の面では微量放射線でも危険とする考え方がその根拠にあることがわかった｡このため,今後は更なる低線量放射線の生体影響研究を進めるとともに,両者の間の隙間をなくす現実的･合理的な対応が求められている｡ No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 14 1 2003 化学発がんの非遺伝毒性的メカニズムの解明に関する最近の動向 1 14 EN Kiyonori Yamaoka Katsumi Hanamoto Yasuhiro Ina Takahiro Kataoka Atsusi Kawabe Masanobu Sano Ayako Ujifuku 10.18926/15202 本総説は,筆者らが進めている｢低線量放射線の健康への影響と医療への応用｣に関する研究に資するために調査した,化学発がんの非遺伝毒性的メカニズムの解明に関する最近の動向の概要についてまとめたものである｡即ち,非遺伝毒性的発がんにおける細胞増殖,シトクロムP450誘導,酸化的ストレス,および遺伝子発現のそれぞれの役割,並びに量的な応答性について言及した｡また,後成的発がんにおけるアポトーシス,およびギャップ結合による情報伝達のそれぞれの役割についても触れた｡その結果,非遺伝毒性的な発がん物質の作用の様式とメカニズムやこれによる後成的な影響などについては解明さ れつつあり,特に,これらの発がん物質がゲノムDNAに対し直接的な相互作用,突然変異,修飾などを行う発がん物質とは機能的に異なった作用をすることが明らかになった｡また,これらは放射線発がんなど低線量放射線の健康への影響などについて研究する上で,重要な知見となっていることもわかった。 No potential conflict of interest relevant to this article was reported.

岡山大学医学部附属病院三朝医療センター Acta Medica Okayama 1348-1258 75 2004 呼吸器疾患に対する温泉療法 ―その臨床効果と作用機序― 61 73 EN Fumihiro Mitsunobu Yasuhiro Hosaki Kozo Ashida Masanori Hamada Kiyonori Yamaoka Yoshiro Tanizaki 10.18926/14757 呼吸器疾患に対する温泉療法は,最近の22年間にわたり行われてきた結果,その有用性は十分明かとなっている｡この22年の間に,温泉療法を受ける対象もかなり変わってきており,例えば気管支喘息では,ステロイド依存性重症難治性喘息の全症例に対する割合は明 らかに低くなってきている｡また,COPDでは最近全症例に対する肺気腫の割合も,また症例数も著明に増加しつつある｡一方,温泉療法を求めて来院される症例数は年ごとに増加する傾向にあり,初期の5年間と比べ,最近の5年間では,気管支喘息では8.2倍,また肺気腫では 34.8倍の増加が観察されている｡呼吸器疾患に対する温泉療法の作用機序としては,直接作用として,自･他覚症状の改善,換気機能の改善,気道過敏性の改善,気道抵抗の低下,肺の過膨脹の改善,過分泌の抑制などが観察される｡一方,間接作用としては,副腎皮質機能の改善,精神的リラックス,抗酸化酵素であるSOD活性の克進などが観察され,これらの間接作用も気管支喘息の病態改善に重要な役割を果しているものと考えられる｡ No potential conflict of interest relevant to this article was reported.

岡山大学保健環境センター環境安全部門 Acta Medica Okayama 0917-1533 27 2005 埋蔵文化財発掘調査および建設工事が環境放射線に及ぼす影響に関する基礎的検討 11 16 EN Tomohiro Nagamatsu Katsumi Hanamoto Toshiro Ono Kiyonori Yamaoka In this paper, we investigated how the excavation of ruins and the construction work affected the environmental radiation in the Shikata campus of Okayama University (S-campus). The environmental radiation was steady in the S-campus until 1997, but began to change since 1998, while the ruin's survey and the construction work started frequently after 1998 in the S-campus. In general, the soil and the concrete include the natural radioisotope (uranium series and thorium series, etc). When ruins are surveyed, it is necessary to move a large amount of the soil. In addition, a large amount of the concrete is used for the construction work. To measure the environmental radiation, the monitor posts were set up on the east and west sides of the building of the Radioisotope Center (RIC). We sampled the soil in the container in each place. We used the high-purity germanium detector to analyze them. The monitor posts showed the difference in the in-air dose rate in each place in the S-campus. The in-air dose rate at the east side of the RIC was higher than that at the west side. The result of analysis showed that the soil includes the (40)K at the east side. While the specific activity of the 40K was 0.849Bq/g at the east side, the (40)K was hardly detected in the soil at the west side. The each soil included the 214-lead and 214-bismus ((214)Pb, (214)Bi), however, there was no significant difference in the specific activity of the each soil. The concrete included (40)K, whose specific activity was 0.492Bq/g. It was suggested that the change of the environmental radiation was attributed to radon and its daughter nuclides in the soil rather than the radiation from the concrete in the buildings. No potential conflict of interest relevant to this article was reported.

岡山大学環境管理センター Acta Medica Okayama 0917-1533 30 2008 岡山大学における核燃料物質の安全管理のための劣化ウランと天然ウランの鑑別について 33 37 EN Tomohiro Nagamatsu Tadashi Hanafusa Ikuo Kinno Akihiro Sakoda Katsumi Hanamoto Kiyonori Yamaoka Toshiro Ono In Japan, the Law for the Regulation of Nuclear Source Materials, Nuclear Fuel Materials and Reactors (Regulation Law) controls the nuclear fuel materials such as thorium (Th), uranium (U) and plutonium (Pu). Under the Regulation Law, all related materials and reactors are needed to register to the Government. In Okayama University, many nuclear fuel materials, mainly uranium compounds, are registered and stored in 11 departments, separately. Discrimination between depleted uranium and natural uranium is important for the observance of the Regulation Law and the safety management of the nuclear fuel materials in the Okayama University. However, the discrimination of the two kind of uranium has poorly analyzed. In this study, we analyzed several uranium compounds by using γ-ray spectrometry to determine whether the depleted uranium or not. No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 10 1 1999 放射線管理区域における作業環境測定の合理化の検討 ―表面汚染と空気汚染の関係に着目して― 1 13 EN Kiyonori Yamaoka Koichi Shibuya Tomohiro Nagamatsu Shoji Kawasaki 10.18926/11728 放射線管理区域において業務従事者の放射線防護が正確に実施されていることを確認するために放射性同位元素の環境測定が行われている。しかし，実際の測定においては，濃度が低いなど実測困難な場合が多いこと，多くの人手と経費を要していることから，より合理的な測定の実施ができないかということについての検討が期待されている。このため本総説では，まず大学などの放射線管理区域における作業環境測定方法の現状についてまとめた。次に，放射線管理区域の床，作業台などにおける放射性同位元素の表面汚染と空気汚染に着目し，汚染粒子の移行など表面汚染と空気汚染の関係機構について，また，スミア法や直接測定法などの各種表面汚染測定法の汚染採取効率などを指標とした特性とこれら測定法の改良の試みについてまとめた。さらに，実際の作業場所において，作業内容，換気，表面材料などが表面汚染と空気汚染の関係に及ぼす影響について，その検討例を紹介した。得られた知見をまとめるとともに，測定箇所・測定頻度の適性化やそれぞれの測定箇所に適した測定法の選定など作業環境測定の一層の合理化に向けて，今後どのような検討が必要なのかについて提案した。 No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 11 1 2000 放射性ヨウ素（(125)I）の空気中濃度測定の簡便化に向けての基礎的検討 35 39 EN Koichi Shibuya Kiyonori Yamaoka Tomohiro Nagamatsu Shoji Kawasaki Yoshio Hiraki 10.18926/11711 放射性ヨウ素（(123)I，(125)I，(131)I）は飛散しやすいなどの特性があり，他の放射性核種に比べ慎重な取扱いが求められている。また，この核種の空気中濃度限度は非常に低く，濃度測定には大量の空気を吸引しなければならず，そのための装置も大掛かりとなる。このため，本研究では，活性炭ろ紙をホルダにセットし，これを注射器に取り付けた簡易な装置を考案・試作し，空気中の放射性ヨウ素濃度を簡便に測る方法について実験・検討した。その結果，まず放射性ヨウ素にNa(125)Iを用いた場合の捕集効率は44.5％であることが分かった。次に，50mℓ注射器を用いて1ℓの空気を吸引・ろ過し，Nal（Tl）ウェルタイプシンチレーションカウンタで30分間放射能を測定した場合，本装置では空気中濃度限度の2.12倍の濃度の(125)Iが測定可能であり，気体状ヨウ素の漏れを防いで捕集効率を94.3％以上に上げることができれば，空気中濃度限度まで測定可能であることが示された。このため，本法は簡便かつ安価に異常を検知する測定方法として利用できるのではないかと考えられた。 No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 11 1 2000 Induction of endogenous antioxidant system by low dose radiation and its applicable possibility for treatment of active oxygen species related diseases 1 15 EN Kiyonori Yamaoka 10.18926/11694 We clarified that adequate oxygen stress induced by low dose radiation activates not only chemical biological protective function, such as induction of the synthesis of SOD, GPX and HSP70, but also the biomembrane function, such as enhanced membrane fluidity and ATPase activity. It is possible that activation of these mechanisms alleviates in vivo oxidation injuries resulting in alleviation of pathologic condition, such as symptoms of hepatopathy and diabetes mellitus. Namely, adequate activation of the functions of the living body by low dose radiation can contribute to suppressing aging and to preventing or reducing active oxygen species related diseases which are thought to involve peroxidation and have been regarded as the diseases for which radon spring water is an effective treatment. Clarification in detail of the mechanisms of these phenomena is required to understand the effects of low dose radiation on the functions of the living body, including adaptive response. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 1994 Study　on　Effects　of　Low　Dose　Radiation　on　Biological　Function　　第1編　Increased　SOD　Activities　and　Decreased　Lipid　Peroxide　Levels　Induced　by　Low　Dose　X　Irradiation　in　Rat　Organs　　第2編　Effects　of　Low　Dose　X-ray　Irradiation　on　Biomembrane　in　Brain　Cortex　of　Aged　Rats　　第3編　Effects　of　Radon　Inhalation　on　Biological　Function-Lipid　Peroxide　Level　Superoxide　Dismutase　Activity　and　Membrane　Fluidity EN No potential conflict of interest relevant to this article was reported.