研究者詳細 - 片岡　隆浩

論文 - 片岡　隆浩

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トロンの生体作用とラドンとの比較に関する研究査読

山岡聖典, 片岡隆浩

74 87 - 89 2025年2月

ラドン温泉療法の適応症とそのメカニズムに関する最近の研究動向査読

片岡隆浩, 迫田晃弘, 神﨑訓枝, 光延文裕, 山岡聖典

日本温泉気候物理医学会雑誌 88 ( 2 ) 1 - 16 2024年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：日本温泉気候物理医学会

早期公開
三朝（鳥取県）の温泉療法は，バドガスタイン（オーストリア）やモンタナ（アメリカ）の坑道療法とともにラドン療法（特にラドン高濃度熱気浴療法）として世界的に有名である．ラドン療法の適応症には，活性酸素種に起因する呼吸器・疼痛・消化器・慢性変性・老年性などに関わる様々な疾患が含まれるが，その多くは経験的処方に基づいている．このため，筆者らはラドンと子孫核種に関連した被ばくの主要経路の特定や体内挙動の実験的・数理的な検討を行い，吸入などにより生じる生体反応と組織・臓器吸収線量との関係をより定量的に評価し，適応症に関わるメカニズムの解明と新たな探索の基礎研究を進めてきた．その結果，メカニズムとしては，ラドン吸入により生じる少量の酸化ストレスに伴う一連の適度な生理刺激作用に関して解明されつつある．すなわち，抗酸化・免疫調節・損傷修復機能の亢進，抗炎症・ホルモン分泌・循環代謝の促進，アポトーシス・熱ショックタンパク質の誘導などである．また，新たな適応症として，炎症性・神経障害性疼痛，炎症性浮腫，胃粘膜損傷，潰瘍性大腸炎，高尿酸血症，1型糖尿病，肝・腎障害，一過性脳虚血発作，うつ病などの可能性が示唆される．さらに，ラドン吸入と抗酸化剤や治療剤との併用による疾患の抑制効果に関して，いずれもその効果を高めることが示唆される．副作用の強い薬剤に対して減薬効果が期待できるため，通常の治療に対するラドン療法の併用効果の更なる臨床的検証が求められる．

DOI： 10.11390/onki.2363

Effect of Radon Inhalation on Murine Brain Proteins: Investigation Using Proteomic and Multivariate Analyses 査読

Shota Naoe, Ayumi Tanaka, Norie Kanzaki, Reiju Takenaka, Akihiro Sakoda, Takaaki, Miyaji, Kiyonori Yamaoka, Takahiro Kataoka

Acta Medica Okayama 78 ( 5 ) 387 - 399 2024年10月

Association between Radon Hot Spring Bathing and Health Conditions: A Cross-Sectional Study in Misasa, Japan 査読

Takahiro Kataoka, Hiroshi Habu, Ayumi Tanaka, Shota Naoe, Kaito Murakami, Yuki Fujimoto, Ryohei Yukimine, Soshi Takao, Fumihiro Mitsunobu, Takashi Yorifuji, Kiyonori Yamaoka

77 ( 4 ) 387 - 394 2023年8月

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 査読

Shota Naoe, Yuki Fujimoto, Kaito Murakami, Ryohei Yukimine, Ayumi Tanaka, Kiyonori Yamaoka, Takahiro Kataoka

Journal of Radiation Research 64 ( 4 ) 635 - 643 2023年5月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Oxford University Press (OUP)

Abstract

The liver’s susceptibility to oxidative stress after a combination of forced swim test (FST) and low-dose-rate γ-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.

DOI： 10.1093/jrr/rrad030

Changes in Sulfur Metabolism in Mouse Brains Following Radon Inhalation 査読

Norie Kanzaki, Akihiro Sakoda, Takahiro Kataoka, Lue Sun, Hiroshi Tanaka, Iwao Ohtsu, Kiyonori Yamaoka

International Journal of Environmental Research and Public Health 19 ( 17 ) 10750 - 10750 2022年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：MDPI AG

Therapy using hot springs, including the high-level radioactive gas “radon”, is traditionally conducted as an alternative treatment for various diseases. Oxidative-stress-related diseases are inhibited by the enhancement of antioxidative functions following radon inhalation. We have reported that radon inhalation increased the level of anti-oxidants, such as glutathione (G-SH), in the brain and had a protective antioxidative effect against transient global cerebral ischemic injury. However, no studies have yet revealed the changes in G-SH associated substances after radon inhalation. In this study, we comprehensively analyzed several metabolites, focusing on G-SH. Mice were exposed to radon at concentrations of 200, 2000, or 20,000 Bq/m3 for 1, 3, or 10 days. We detected 27 metabolites in the mouse brains. The result showed that the L-methionine levels increased, whereas the levels of urea, glutathione, and sulfite ion decreased under any condition. Although the ratio of G-SH to oxidized glutathione (GS-SG) decreased, glutathione monosulfide (G-S-SH) and cysteine monosulfide (Cys-S-SH) increased after radon inhalation. G-S-SH and Cys-S-SH can produce a biological defense against the imbalance of the redox state at very low-dose irradiation following radon inhalation because they are strong scavengers of reactive oxygen species. Additionally, we performed an overall assessment of high-dimensional data and showed some specific characteristics. We showed the changes in metabolites after radon inhalation using partial least squares-discriminant analysis and self-organizing maps. The results showed the health effects of radon, especially the state of sulfur-related metabolites in mouse brains under the exposure conditions for radon therapy.

DOI： 10.3390/ijerph191710750

Immunomodulatory Effects of Radon Inhalation on Lipopolysaccharide-Induced Inflammation in Mice 査読

Takahiro Kataoka, Shota Naoe, Kaito Murakami, Yuki Fujimoto, Ryohei Yukimine, Ayumi Tanaka, Kiyonori Yamaoka

International Journal of Environmental Research and Public Health 19 ( 17 ) 10632 - 10632 2022年8月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：MDPI AG

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/m3 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-α, 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.

DOI： 10.3390/ijerph191710632

Potential inhibitory effects of low-dose thoron inhalation and ascorbic acid administration on alcohol-induced hepatopathy in mice 査読

Takahiro Kataoka, Tsuyoshi Ishida, Shota Naoe, Norie Kanzaki, Akihiro Sakoda, Hiroshi Tanaka, Fumihiro Mitsunobu, Kiyonori Yamaoka

Journal of Radiation Research 63 ( 5 ) 719 - 729 2022年7月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Oxford University Press (OUP)

Abstract

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/m3 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/m3) and AA administration 24 h after alcohol administration effectively inhibited alcohol-induced liver damage. The combination of thoron inhalation (500 Bq/m3) 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/m3 thoron inhalation was lower than that after 500 Bq/m3 thoron inhalation. These findings suggest that the combination of thoron inhalation at 500 Bq/m3 and AA administration has positive effects on the recovery from alcohol-induced liver damage. The results also suggested that thoron inhalation at 500 Bq/m3 was more effective than that at 2000 Bq/m3, possibly because of the decrease in GSH content in the liver. In conclusion, the combination of thoron inhalation at 500 Bq/m3 and AA administration promoted an early recovery from alcohol-induced liver damage.

DOI： 10.1093/jrr/rrac046

A simple method for estimating the potential of the pyroelectric crystal surface 査読

Katsumi Hanamoto, Takahiro Kataoka, Kiyonori Yamaoka

Applied Radiation and Isotopes 185 110230 - 110230 2022年7月

Radon Solubility and Diffusion in the Skin Surface Layer

Akihiro Sakoda, Tsuyoshi Ishida, Norie Kanzaki, Hiroshi Tanaka, Takahiro Kataoka, Fumihiro Mitsunobu, Kiyonori Yamaoka

International Journal of Environmental Research and Public Health 19 ( 13 ) 7761 - 7761 2022年6月

掲載種別：研究論文（学術雑誌）出版者・発行元：MDPI AG

In specific situations such as bathing in a radon spa, where the radon activity concentration in thermal water is far higher than that in air, it has been revealed that radon uptake via skin can occur and should be considered for more precise dose evaluation. The primary aim of the present study was to numerically demonstrate the distribution as well as the degree of diffusion of radon in the skin, with a focus on its surface layer (i.e., stratum corneum). We developed a biokinetic model that included diffusion theory at the stratum corneum, and measured radon solubility in that tissue layer as a crucial parameter. The implementation of the model suggested that the diffusion coefficient in the stratum corneum was as low as general radon-proof sheets. After a 20-min immersion in water, the simulated depth profile of radon in the skin showed that the radon activity concentration at the top surface skin layer was approximately 103 times higher than that at the viable skin layer. The information on the position of radon as a radiation source would contribute to special dose evaluation where specific target cell layers are assumed for the skin.

DOI： 10.3390/ijerph19137761

Confirmation of efficacy, elucidation of mechanism, and new search for indications of radon therapy

Kiyonori Yamaoka, Takahiro Kataoka

Journal of Clinical Biochemistry and Nutrition 70 ( 2 ) 87 - 92 2022年

Mechanisms of action of radon therapy on cytokine levels in normal mice and rheumatoid arthritis mouse model 査読

Takahiro Kataoka, Shota Naoe, Kaito Murakami, Ryohei Yukimine, Yuki Fujimoto, Norie Kanzaki, Akihiro Sakoda, Fumihiro Mitsunobu, Kiyonori Yamaoka

Journal of Clinical Biochemistry and Nutrition 70 ( 2 ) 154 - 159 2022年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：The Society for Free Radical Research Japan

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.

DOI： 10.3164/jcbn.21-91

Radon inhalation decreases DNA damage induced by oxidative stress in mouse organs via the activation of antioxidative functions 査読

Takahiro Kataoka, Hina Shuto, Shota Naoe, Junki Yano, Norie Kanzaki, Akihiro Sakoda, Hiroshi Tanaka, Katsumi Hanamoto, Fumihiro Mitsunobu, Hiroaki Terato, Kiyonori Yamaoka

Journal of Radiation Research 62 ( 5 ) 861 - 867 2021年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Oxford University Press (OUP)

<title>Abstract</title>
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/m3 (for one, three, or 10 days). The 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels decreased in the brains of mice that inhaled 20 kBq/m3 radon for three days and in the kidneys of mice that inhaled 2 or 20 kBq/m3 radon for one, three or 10 days. The 8-OHdG levels in the small intestine decreased by approximately 20–40% (2 kBq/m3 for three days or 20 kBq/m3 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.

DOI： 10.1093/jrr/rrab069

Dosimetry of radon progeny deposited on skin in air and thermal water

Akihiro Sakoda, Yuu Ishimori, Norie Kanzaki, Hiroshi Tanaka, Takahiro Kataoka, Fumihiro Mitsunobu, Kiyonori Yamaoka

Journal of Radiation Research 62 ( 4 ) 634 - 644 2021年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Oxford University Press (OUP)

<title>Abstract</title>
It is held that the skin dose from radon progeny is not negligibly small and that introducing cancer is a possible consequence under normal circumstances as there are a number of uncertainties in terms of related parameters such as activity concentrations in air and water, target cells in skin, skin covering materials, and deposition velocities. An interesting proposal has emerged in that skin exposure to natural radon-rich thermal water as part of balneotherapy can produce an immune response to induce beneficial health effects. The goal of this study was to obtain generic dose coefficients with a focus on the radon progeny deposited on the skin in air or water in relation to risk or treatment assessments. We thus first estimated the skin deposition velocities of radon progeny in air and thermal water based on data from the latest human studies. Skin dosimetry was then performed under different assumptions regarding alpha-emitting source position and target cell (i.e. basal cells or Langerhans cells). Furthermore, the impact of the radon progeny deposition on effective doses from all exposure pathways relating to ‘radon exposure’ was assessed using various possible scenarios. It was found that in both exposure media, effective doses from radon progeny inhalation are one to four orders of magnitude higher than those from the other pathways. In addition, absorbed doses on the skin can be the highest among all pathways when the radon activity concentrations in water are two or more orders of magnitude higher than those in air.

DOI： 10.1093/jrr/rrab030

The Effects of Low-Dose-Rate γ-irradiation on Forced Swim Test-Induced Immobility and Oxidative Stress in Mice

Tetsuya Nakada, Takahiro Kataoka, Takaharu Nomura, Hina Shuto, Junki Yano, Shota Naoe, Katsumi Hanamoto, Kiyonori Yamaoka

Acta Medica Okayama 75 ( 2 ) 169 - 175 2021年4月

記述言語：英語掲載種別：研究論文（学術雑誌）

The forced swim test (FST) induces immobility in mice. Low-dose (high-dose-rate) X-irradiation inhibits FSTinduced immobility in mice due to its antioxidative function. We evaluated the effects of low-dose γ-irradiation at a low-dose-rate on the FST-induced depletion of antioxidants in mouse organs. Mice received whole-body low-dose-rate (0.6 or 3.0 mGy/h) of low-dose γ-irradiation for 1 week, followed by daily FSTs (5 days). The immobility rate on day 2 compared to day 1 was significantly lower in the 3.0 mGy/h irradiated mice than in sham irradiated mice. The FST significantly decreased the catalase (CAT) activity and total glutathione (t-GSH) content in the brain and kidney, respectively. The superoxide dismutase (SOD) activity and t-GSH content in the liver of the 3.0 mGy/h irradiated mice were significantly lower than those of the non-FST-treated mice. The CAT activity in the lungs of mice exposed to 3.0 mGy/h γ-irradiation was higher than that of non-FST treated mice and mice treated with FST. However, no significant differences were observed in the levels of these antioxidant markers between the sham and irradiated groups except for the CAT activity in lungs. These findings suggest that the effects of low-dose-rate and low-dose γ-irradiation on FST are highly organ-dependent.

DOI： 10.18926/AMO/61896

Evaluation of the redox state in mouse organs following radon inhalation

Takahiro Kataoka, Norie Kanzaki, Akihiro Sakoda, Hina Shuto, Junki Yano, Shota Naoe, Hiroshi Tanaka, Katsumi Hanamoto, Hiroaki Terato, Fumihiro Mitsunobu, Kiyonori Yamaoka

Journal of Radiation Research 62 ( 2 ) 206 - 216 2021年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Oxford University Press (OUP)

<title>Abstract</title>
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/m3 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.

DOI： 10.1093/jrr/rraa129

Comparison of antioxidative effects between radon and thoron inhalation in mouse organs 国際誌

Yusuke Kobashi, Takahiro Kataoka, Norie Kanzaki, Tsuyoshi Ishida, Akihiro Sakoda, Hiroshi Tanaka, Yuu Ishimori, Fumihiro Mitsunobu, Kiyonori Yamaoka

Radiation and Environmental Biophysics 59 ( 3 ) 473 - 482 2020年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

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.

DOI： 10.1007/s00411-020-00843-0

その他リンク： http://link.springer.com/article/10.1007/s00411-020-00843-0/fulltext.html

X-Irradiation at 0.5 Gy after the forced swim test reduces forced swimming-induced immobility in mice

Takahiro Kataoka, Hina Shuto, Junki Yano, Shota Naoe, Tsuyoshi Ishida, Tetsuya Nakada, Keiko Yamato, Katsumi Hanamoto, Takaharu Nomura, Kiyonori Yamaoka

Journal of Radiation Research 61 ( 4 ) 517 - 523 2020年7月

掲載種別：研究論文（学術雑誌）出版者・発行元：Oxford University Press (OUP)

<title>Abstract</title>
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 4 h 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.

DOI： 10.1093/jrr/rraa022

Basic study on enhancement of antioxidant function by Low-dose irradiation in mouse brain and its combined effect with ascorbic acid 査読

Takahiro Kataoka, Yuto Yunoki, Norie Kanzaki, Kaori Sasaoka, Yusuke Kobashi, Tsuyoshi Ishida, Katsumi Hanamoto, Kiyonori Yamaoka

Radioisotopes 69 ( 2 ) 45 - 53 2020年

Reduction of radiation exposure in patients and cardiologists using a noise reduction technique in cardiac catheterization and percutaneous coronary intervention

Masayuki Kumashiro, Takahiro Kataoka, Shinobu Yokota, Shinobu Nakagawa, Fumiaki Kiyokawa, Hideki Mitsui, Shinji Osumi, Kiyonori Yamaoka

Journal of JART 66 45 - 57 2019年

Comparative Effects of Radon Inhalation According to Mouse Strain and Cisplatin Dose in a Cisplatin-induced Renal Damage Model

Sasaoka, Kaori, Kataoka, Takahiro, Kanzaki, Norie, Kobashi, Yusuke, Sakoda, Akihiro, Ishimori, Yuu, Yamaoka, Kiyonori

PAKISTAN JOURNAL OF ZOOLOGY 50 ( 3 ) 1157 - 1170 2018年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ZOOLOGICAL SOC PAKISTAN

Cisplatin (CDDP) is widely used for treating solid cancers; however, it induces nephrotoxicity caused by oxidative stress. Here, we investigated whether radon inhalation has different effects against CDDP-induced renal injury in two mouse strains differing in radiosensitivity, and determined the appropriate dose of CDDP combined with radon inhalation for highly radiosensitive mice. CDDP was administered at 20 mg/kg weight to C57BL/6J and BALB/c mice after radon inhalation at 1000 Bq/m(3) and 2000 Bq/m(3) for 24 h. Radon inhalation had a slight positive effect against CDDP toxicity in C57BL/6J mice with respect to improved hair condition, whereas radon inhalation exacerbated CDDP-induced toxicity in BALB/c mice, such as a decrease in hair condition, higher creatinine levels, and decreased antioxidant contents (catalase and glutathione). When BALB/c mice were treated with a lower dose of CDDP (15 mg/kg) after 1000 Bq/m(3) radon inhalation, the creatinine level was reduced and the superoxide dismutase content was increased, suggesting that this combination might have a protective effect against the CDDP-induced renal damage. The supportive effect of radon inhalation shows its good potential as a candidate treatment to alleviate CDDP-induced renal damage in veterinary medicine.

DOI： 10.17582/journal.pjz/2018.50.3.1157.1170

Pressure dependence of X-rays produced by an LiTaO3 single crystal over a wide range of pressure

Katsumi Hanamoto, Takahiro Kataoka, Kiyonori Yamaoka

Applied Radiation and Isotopes 135 40 - 42 2018年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Elsevier Ltd

The energy spectra of X-rays produced by an LiTaO3 single crystal have been measured at the pressures of 8 × 10−4−4 Pa. The energy spectra showed that the endpoint energy steadily increased with decrease of pressure at 2–4 Pa and gradually decreased with decrease of pressure at 0.1–2 Pa, and became almost constant below 0.1 Pa. The amount of X-rays steadily increased with decrease of pressure at 2–4 Pa and almost saturated below 0.5 Pa. The change of X-rays produced by the LiTaO3 single crystal was compared with the previous works and discussed in relation to the distance between the crystal surface and the target.

DOI： 10.1016/j.apradiso.2018.01.019

ラドン吸入による抗酸化機能の亢進と抗酸化ビタミン摂取との複合効果に関する研究動向査読

片岡隆浩, 山岡聖典

放射線生物研究 53 ( 3 ) 211 - 222 2018年

記述言語：日本語出版者・発行元：放射線生物研究会

ラドン療法には疼痛性・呼吸器・消化器などの疾患に対し症状緩和の効果があることが、臨床試験に結果に基づき報告されている。また、我々は動物実験などにより、これら症状緩和のメカニズムには抗酸化機能などの生体防御機能の亢進が関与していることも明らかにしてきた。本稿では、この内、ラドン吸入による抗酸化機能の亢進と、これと抗酸化ビタミン摂取の複合効果に関して、我々の得た研究成果を中心に概説する。すなわち、マウスにおいて四塩化炭素(CCl4)誘導障害の抑制の程度から、肝臓では1000Bq/m3または2000Bq/m3のラドンを24時間吸入させた場合と500mg/kg体重アスコルビン酸または300mg/kg体重α-トコフェロールの摂取が、腎臓では2000Bq/m3のラドンを24時間吸入と300〜500mg/kg体重α-トコフェロール摂取が、それぞれ等しい効果であった。また、スナネズミにおいて一過性脳虚血に伴う海馬CAl領域の細胞損傷の抑制の程度から、2000Bq/m3のラドンを24時間吸入と500mg/kg体重アスコルビン酸摂取が等しい効果であった。他方、急性アルコール性マウス肝障害に対し、ラドン吸入とアスコルビン酸またはα-トコフェロールの摂取の併用に複合的な抑制があった。また、神経障害性マウス疼痛に対し、ラドン吸入とプレガバリン摂取の併用には相加効果があった。以上の所見などから、ラドン吸入は多くの臓器・組織において抗酸化機能を亢進し、多くの活性酸素由来の疾患の通常治療との併用により効果を高めることが示唆できた。(著者抄録)

Knowledge discovery of suppressive effect of disease and increased anti-oxidative function by low-dose radiation using self-organizing map

Norie Kanzaki, Takahiro Kataoka, Yusuke Kobashi, Yuto Yunoki, Tsuyoshi Ishida, Akihiro Sakoda, Yuu Ishimori, Kiyonori Yamaoka

RADIOISOTOPES 67 ( 2 ) 43 - 57 2018年

Image quality of the coronary angiography with noise reduction technology to decrease the radiation dose

Masayuki Kumashiro, Takahiro Kataoka, Shinobu Yokota, Shinobu Nakagawa, Keisuke Otsuki, Nobuyuki Miyake, Shinji Osumi, Kiyonori Yamaoka

Acta Medica Okayama 72 ( 2 ) 153 - 164 2018年

心臓カテーテル検査およびPCIにおける雑音低減技術を用いた患者と術者の被ばく低減効果

熊代正行, 片岡隆浩, 横田忍, 中川忍, 清川文秋, 光井英樹, 大角真司, 山岡聖典

日本診療放射線技師会誌 65 ( 5 ) 31 - 40 2018年

Radon inhalation induces manganese-superoxide dismutase in mouse brain via nuclear factor-κB activation

Takahiro Kataoka, Reo Etani, Norie Kanzaki, Yusuke Kobashi, Yuto Yunoki, Tsuyoshi Ishida, Akihiro Sakoda, Yuu Ishimori, Kiyonori Yamaoka

Journal of Radiation Research 58 ( 6 ) 887 - 893 2017年11月

Protective effects of hot spring water drinking and radon inhalation on ethanol-induced gastric mucosal injury in mice

Reo Etani, Takahiro Kataoka, Norie Kanzaki, Akihiro Sakoda, Hiroshi Tanaka, Yuu Ishimori, Fumihiro Mitsunobu, Takehito Taguchi, Kiyonori Yamaoka

JOURNAL OF RADIATION RESEARCH 58 ( 5 ) 614 - 625 2017年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

Radon therapy using radon (Rn-222) gas is classified into two types of treatment: inhalation of radon gas and drinking water containing radon. Although short- or long-term intake of spa water is effective in increasing gastric mucosal blood flow, and spa water therapy is useful for treating chronic gastritis and gastric ulcer, the underlying mechanisms for and precise effects of radon protection against mucosal injury are unclear. In the present study, we examined the protective effects of hot spring water drinking and radon inhalation on ethanol-induced gastric mucosal injury in mice. Mice inhaled radon at a concentration of 2000 Bq/m(3) for 24 h or were provided with hot spring water for 2 weeks. The activity density of Rn-222 ranged from 663 Bq/l (start point of supplying) to 100 Bq/l (end point of supplying). Mice were then orally administered ethanol at three concentrations. The ulcer index (UI), an indicator of mucosal injury, increased in response to the administration of ethanol; however, treatment with either radon inhalation or hot spring water inhibited the elevation in the UI due to ethanol. Although no significant differences in antioxidative enzymes were observed between the radon-treated groups and the non-treated control groups, lipid peroxide levels were significantly lower in the stomachs of mice pre-treated with radon or hot spring water. These results suggest that hot spring water drinking and radon inhalation inhibit ethanol-induced gastric mucosal injury.

DOI： 10.1093/jrr/rrx021

Measurements of radon activity concentration in mouse tissues and organs

Yuu Ishimori, Hiroshi Tanaka, Akihiro Sakoda, Takahiro Kataoka, Kiyonori Yamaoka, Fumihiro Mitsunobu

RADIATION AND ENVIRONMENTAL BIOPHYSICS 56 ( 2 ) 161 - 165 2017年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

The purpose of this study is to investigate the biokinetics of inhaled radon, radon activity concentrations in mouse tissues and organs were determined after mice had been exposed to about 1 MBq/m(3) of radon in air. Radon activity concentrations in mouse blood and in other tissues and organs were measured with a liquid scintillation counter and with a well-type HP Ge detector, respectively. Radon activity concentration in mouse blood was 0.410 +/- 0.016 Bq/g when saturated with 1 MBq/m(3) of radon activity concentration in air. In addition, average partition coefficients obtained were 0.74 +/- 0.19 for liver, 0.46 +/- 0.13 for muscle, 9.09 +/- 0.49 for adipose tissue, and 0.22 +/- 0.04 for other organs. With these results, a value of 0.414 for the blood-to-air partition coefficient was calculated by means of our physiologically based pharmacokinetic model. The time variation of radon activity concentration in mouse blood during exposure to radon was also calculated. All results are compared in detail with those found in the literature.

DOI： 10.1007/s00411-017-0682-9

Analysis of liver damage from radon, X-ray, or alcohol treatments in mice using a self-organizing map

Norie Kanzaki, Takahiro Kataoka, Reo Etani, Kaori Sasaoka, Akihiro Kanagawa, Kiyonori Yamaoka

JOURNAL OF RADIATION RESEARCH 58 ( 1 ) 33 - 40 2017年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

In our previous studies, we found that low-dose radiation inhibits oxidative stress-induced diseases due to increased antioxidants. Although these effects of low-dose radiation were demonstrated, further research was needed to clarify the effects. However, the analysis of oxidative stress is challenging, especially that of low levels of oxidative stress, because antioxidative substances are intricately involved. Thus, we proposed an approach for analysing oxidative liver damage via use of a self-organizing map (SOM)-a novel and comprehensive technique for evaluating hepatic and antioxidative function. Mice were treated with radon inhalation, irradiated with X-rays, or subjected to intraperitoneal injection of alcohol. We evaluated the oxidative damage levels in the liver from the SOM results for hepatic function and antioxidative substances. The results showed that the effects of low-dose irradiation (radon inhalation at a concentration of up to 2000 Bq/m(3), or X-irradiation at a dose of up to 2.0 Gy) were comparable with the effect of alcohol administration at 0.5 g/kg bodyweight. Analysis using the SOM to discriminate small changes was made possible by its ability to 'learn' to adapt to unexpected changes. Moreover, when using a spherical SOM, the method comprehensively examined liver damage by radon, X-ray, and alcohol. We found that the types of liver damage caused by radon, X-rays, and alcohol have different characteristics. Therefore, our approaches would be useful as a method for evaluating oxidative liver damage caused by radon, X-rays and alcohol.

DOI： 10.1093/jrr/rrw083

Pressure dependence of X-rays produced by an LiTaO3 single crystal at the pressures of 1-20 Pa

Katsumi Hanamoto, Takahiro Kataoka, Kiyonori Yamaoka

APPLIED RADIATION AND ISOTOPES 116 134 - 137 2016年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The energy spectra of X-rays produced by an LiTaO3 single crystal have been measured at pressures of 1-20 Pa. The energy spectra showed that the endpoint energy and the amount of X-rays gradually increased with the decrease of pressure at 5-8 Pa and abruptly increased around 4 Pa and below. A maximum endpoint energy of 70 keV was obtained using the LiTaO3 single crystal with 5 mm thickness at a pressure of 3 Pa. The change of X-rays produced by the LiTaO(3)single crystal was discussed in relation to the breakdown potential at the pressures. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.apradiso.2016.08.003

Difference in the action mechanism of radon inhalation and radon hot spring water drinking in suppression of hyperuricemia in mice

Reo Etani, Takahiro Kataoka, Norie Kanzaki, Akihiro Sakoda, Hiroshi Tanaka, Yuu Ishimori, Fumihiro Mitsunobu, Kiyonori Yamaoka

JOURNAL OF RADIATION RESEARCH 57 ( 3 ) 250 - 257 2016年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

Although radon therapy is indicated for hyperuricemia, the underlying mechanisms of action have not yet been elucidated in detail. Therefore, we herein examined the inhibitory effects of radon inhalation and hot spring water drinking on potassium oxonate (PO)-induced hyperuricemia in mice. Mice inhaled radon at a concentration of 2000 Bq/m(3) for 24 h or were given hot spring water for 2 weeks. Mice were then administrated PO at a dose of 500 mg/kg. The results obtained showed that serum uric acid levels were significantly increased by the administration of PO. Radon inhalation or hot spring water drinking significantly inhibited elevations in serum uric acid levels through the suppression of xanthine oxidase activity in the liver. Radon inhalation activated anti-oxidative functions in the liver and kidney. These results suggest that radon inhalation inhibits PO-induced hyperuricemia by activating anti-oxidative functions, while hot spring water drinking may suppress PO-induced elevations in serum uric acid levels through the pharmacological effects of the chemical compositions dissolved in it.

DOI： 10.1093/jrr/rrw014

Possible applications of radon therapy in veterinary care for oxidative stress-induced kidney damage

Kaori Sasaoka, Takahiro Kataoka, Norie Kanzaki, Kiyonori Yamaoka

Free Radicals and Health 61 - 74 2016年1月

掲載種別：論文集(書籍)内論文

Oxidative stress in the body is considered an imbalance between the production and removal of reactive oxygen species (ROS). Ischemic acute renal failure, chronic renal failure, uremia, glomerulonephritis, and diabetic nephropathy are ROS-related diseases. In the veterinary field, a few studies of chronic kidney failure related to oxidative stress have been reported. Radon therapy has been used in Japan and Europe, and has been shown to have beneficial effects on ROS-related diseases such as bronchial asthma, arteriosclerosis, osteoarthritis, and pain-related diseases. We have demonstrated that radon inhalation increases antioxidative functions in kidney, and inhibits oxidative stress-induced kidney damage in animals. In addition, radon exposure systems for pets have already been developed. Therefore, we review the possible applications of radon therapy in veterinary care for oxidative stress-induced kidney damage.

Activation of Antioxidative Functions by Radon Inhalation Enhances the Mitigation Effects of Pregabalin on Chronic Constriction Injury-Induced Neuropathic Pain in Mice

Takahiro Kataoka, Shunsuke Horie, Reo Etani, Norie Kanzaki, Kaori Sasaoka, Yusuke Kobashi, Katsumi Hanamoto, Kiyonori Yamaoka

OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016 2016年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：HINDAWI LTD

Radon inhalation brings pain relief for chronic constriction injury- (CCI-) induced neuropathic pain in mice due to the activation of antioxidative functions, which is different from the mechanism of the pregabalin effect. In this study, we assessed whether a combination of radon inhalation and pregabalin administration is more effective against neuropathic pain than radon or pregabalin only. Mice were treated with inhaled radon at a concentration of 1,000 Bq/m(3) for 24 hours and pregabalin administration after CCI surgery. In mice treated with pregabalin at a dose of 3 mg/kg weight, the 50% paw withdrawal threshold of mice treated with pregabalin or radon and pregabalin was significantly increased, suggesting pain relief. The therapeutic effects of radon inhalation or the combined effects of radon and pregabalin (3 mg/kg weight) were almost equivalent to treatment with pregabalin at a dose of 1.4 mg/kg weight or 4.1 mg/kg weight, respectively. Radon inhalation and the combination of radon and pregabalin increased antioxidant associated substances in the paw. The antioxidant substances increased much more in radon inhalation than in pregabalin administration. These findings suggested that the activation of antioxidative functions by radon inhalation enhances the pain relief of pregabalin and that this combined effect is probably an additive effect.

DOI： 10.1155/2016/9853692

Radon inhalation suppresses nephropathy in streptozotocin-induced type-1 diabetic mice

Yuichi Nishiyama, Takahiro Kataoka, Keiko Yamato, Reo Etani, Takehito Taguchi, Kiyonori Yamaoka

JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY 53 ( 6 ) 909 - 915 2016年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

In this study, we investigated the suppressive effects of radon inhalation against nephropathy in C57BL/6J mice with type-1 diabetes induced by intraperitoneal injection of streptozotocin (50 mg/kg weight, given five times). Four weeks after diabetes induction, the diabetic mice were continuously treated with inhaled radon-222 of 2000 Bq/m(3) or air only (sham) for four weeks. The results showed that radon inhalation did not affect type-1 diabetic symptoms such as body weight loss, hyperglycemia, and hypoinsulinemia. However, diabetic mice treated with radon showed lower urinary albumin excretion and fibrotic change in renal glomeruli compared with diabetic mice not treated with radon. Furthermore, renal superoxide dismutase activity and glutathione content were significantly higher in diabetic mice treated with radon than in diabetic mice not treated with radon. These findings suggested that radon inhalation enhanced renal antioxidants activities, resulting in the suppression of diabetic nephropathy. This study may contribute to the development of a novel approach in the treatment of nephropathy for diabetic patients.

DOI： 10.1080/00223131.2015.1078751

Study on Antidepressant-Like Effects of Radon Inhalation on Forced Swim Induced Depression in Mice

Keiko Yamato, Takahiro Kataoka, Yuichi Nishiyama, Yuji Takata, Reo Etani, Kiyonori Yamaoka

RADIOISOTOPES 65 ( 12 ) 493 - 506 2016年

Evaluating the protective effects of radon inhalation or ascorbic acid treatment after transient global cerebral ischemic injury in gerbils

Takahiro Kataoka, Reo Etani, Norie Kanzaki, Kaori Sasaoka, Yusuke Kobashi, Katsumi Hanamoto, Takehito Taguchi, Kiyonori Yamaoka

JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY 53 ( 11 ) 1681 - 1685 2016年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

In this study, we compared the protective effects of radon inhalation and ascorbic acid administration on transient global cerebral ischemic injury in gerbils. Gerbils were treated with radon inhalation (2000 Bq/m(3), 24 hours) or ascorbic acid (100, 300, or 500mg/kg body weight). Then, transient global cerebral ischemia was induced by bilateral occlusion of the common carotid artery. Results showed that the number of damaged neurons was significantly increased in gerbils that underwent ischemia compared with that in control gerbils. However, the number of damaged neurons in gerbils treated with radon or 500mg/kg of ascorbic acid before ischemia was significantly lower than gerbils who were subjected to ischemia without any pretreatment, and the protective effects of radon inhalation were similar to the effects of administering 500mg/kg ascorbic acid. The levels of superoxide dismutase (SOD) and total glutathione (t-GSH) in brain tissue were increased to a similar extent by pretreatment with radon inhalation or 500mg/kg of ascorbic acid. These findings suggested that radon inhalation has a protective antioxidative effect against transient global cerebral ischemic injury similar to 500mg/kg ascorbic acid treatment.

DOI： 10.1080/00223131.2016.1198731

Combined effects of radon inhalation and antioxidant vitamin administration on acute alcohol-induced hepatopathy in mice

Reo Etani, Takahiro Kataoka, Yuichi Nishiyama, Yuji Takata, Kiyonori Yamaoka

JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY 52 ( 12 ) 1512 - 1518 2015年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

It has been reported that radon inhalation activates antioxidative functions in liver and has an antioxidative effect against hepatopathy similar to that of the antioxidative effects of ascorbic acid (VC) or -tocopherol (VE). In this study, we examined the combined effects of radon inhalation and antioxidant vitamin administration on acute alcohol-induced hepatopathy in mice. ICR mice were subjected to intraperitoneal (i.p.) administration of alcohol after pretreating with air only (sham) or radon at a concentration of approximately 2000 Bq/m(3) for 24 hours and i.p. administration of VC (300 mg/kg body weight) or VE (300 mg/kg body weight). In mice injected with alcohol, the combined radon and antioxidant vitamins treatment significantly decreased the activities of glutamic oxaloacetic transaminase in serum compared to not only the alcohol-administered group (sham group), but also the radon inhalation with alcohol administration group or the vitamin and alcohol administration group. In addition, radon inhalation significantly increased the antioxidant level, in such as the catalase activity and the total glutathione content in liver compared to the sham group. These results suggested that the combined radon and antioxidant vitamin treatment could effectively inhibit alcohol-induced hepatopathy in mice without any antagonizing action.

DOI： 10.1080/00223131.2015.1014875

The possible applications of radon inhalation treatment as antioxidant therapy for hepatopathy

Takahiro Kataoka, Akihiro Sakoda, Reo Etani, Yuu Ishimori, Fumihiro Mitsunobu, Kiyonori Yamaoka

Radon: Geology, Environmental Impact and Toxicity Concerns 133 - 148 2015年1月

掲載種別：論文集(書籍)内論文

The possibility of antioxidant therapy has been reported for several diseases such as ischemic stroke. The therapy could also be applied for diseases caused by reactive oxygen species (ROS). It has been reported that ROS or free radicals may cause various types of hepatopathy, including alcoholic liver disease. Low dose (0.5 Gy) X- or γ- irradiation activates the antioxidative functions of the mouse liver and inhibits ROS- or free radical-induced hepatopathy. Radon therapy is performed mainly for pain-related diseases in Japan and Europe. Several clinical studies have been reported, but the possible mechanisms of the beneficial effects remain unknown. Recently, we have reported that the possible mechanism of radon therapy is the activation of antioxidative functions following radon inhalation. For example, radon inhalation inhibits and alleviates chronic constriction injury induced pain or inflammatory pain in mice due to the activation of antioxidative functions. In addition, although hepatopathy is not the main indication for radon therapy, our recent studies suggested that radon inhalation inhibits hepatopathy caused by ROS or free radicals. In this chapter, based on experiments with mice, we reviewed the possible applications of radon inhalation as an antioxidant therapy for hepatopathy from the viewpoints of recent antioxidant therapy, hepatopathy induced by ROS or free radicals, and the beneficial effects of radon inhalation for hepatopathy.

三朝ラドン温泉の健康効果に関する最近の研究動向

片岡隆浩, 迫田晃弘, 恵谷玲央, 石森有, 光延文裕, 山岡聖典

温泉科学 64 ( 4 ) 380 - 387 2015年

記述言語：日本語出版者・発行元：(一社)日本温泉科学会

岡山大学病院三朝医療センターではラドン温泉を活用したラドン療法が実施されており、適応症として例えば変性性関節症に伴う疼痛がある。臨床試験による実証報告例は多くあるものの、なぜ有効であるかのメカニズムの解明に関する研究報告例は少ない。本稿では、放射能効果の観点から近年得られた筆者らのラドン健康効果の研究成果を中心に概説した。すなわち、小動物用ラドン吸入装置を開発し、三朝医療センターに隣接した三朝ラドン効果研究施設内に設置した。これを用い、例えば、マウス諸臓器中の抗酸化酵素活性のラドン濃度・吸入時間の依存性について検討した。その結果、多くの臓器でsuperoxide dismutase(SOD)活性が増加したことから、ラドン吸入は抗酸化機能を亢進させることがわかった。また、streptozotocin(STZ)誘導マウスI型糖尿病の症状緩和について検討した。その結果、ラドン吸入による膵臓中の抗酸化機能の亢進に伴い膵島の酸化ストレスが緩和されることでインスリンの分泌機能の低下が抑制され、I型糖尿病が緩和することもわかった。以上の所見などから、ラドン吸入は抗酸化機能などを亢進させ活性酸素由来の疾患の症状を緩和するメカニズムの一端が明らかにできた。(著者抄録)

その他リンク： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2015&ichushi_jid=J00191&link_issn=&doc_id=20150513080001&doc_link_id=%2Ffd5onsen%2F2015%2F006404%2F003%2F0380-0387%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Ffd5onsen%2F2015%2F006404%2F003%2F0380-0387%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Recent Studies on Anti-inflammatory Effects of Radon Inhalation in Mice

Norie Kanzaki, Takahiro Kataoka, Reo Etani, Kiyonori Yamaoka

Inflammation & Cell Signaling 1 ( 6 ) 1 - 5 2015年

Radon Inhalation Protects Against Transient Global Cerebral Ischemic Injury in Gerbils

Takahiro Kataoka, Reo Etani, Yuji Takata, Yuichi Nishiyama, Atsushi Kawabe, Masayuki Kumashiro, Takehito Taguchi, Kiyonori Yamaoka

INFLAMMATION 37 ( 5 ) 1675 - 1682 2014年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER/PLENUM PUBLISHERS

Although brain disorders are not the main indication for radon therapy, our previous study suggested that radon inhalation therapy might mitigate brain disorders. In this study, we assessed whether radon inhalation protects against transient global cerebral ischemic injury in gerbils. Gerbils were treated with inhaled radon at a concentration of 2,000 Bq/m(3) for 24 h. After radon inhalation, transient global cerebral ischemia was induced by bilateral occlusion of the common carotid artery. Results showed that transient global cerebral ischemia induced neuronal damage in hippocampal CA1, and the number of damaged neurons was significantly increased compared with control. However, radon treatment inhibited ischemic damage. Superoxide dismutase (SOD) activity in the radon-treated gerbil brain was significantly higher than that in sham-operated gerbils. These findings suggested that radon inhalation activates antioxidative function, especially SOD, thereby inhibiting transient global cerebral ischemic injury in gerbils.

DOI： 10.1007/s10753-014-9896-z

Effects of cream containing ultralow volume radionuclides on carrageenan-induced inflammatory paw edema in mice

Takahiro Kataoka, Yuji Takata, Reo Etani, Yuichi Nishiyama, Atsushi Kawabe, Katsumi Hanamoto, Takehito Taguchi, Kiyonori Yamaoka

Biochemistry & Physiology 3 ( 2 ) 1 - 5 2014年

Absorbed doses of lungs from radon retained in airway lumens of mice and rats

Akihiro Sakoda, Yuu Ishimori, Kiyonori Yamaoka, Takahiro Kataoka, Fumihiro Mitsunobu

RADIATION AND ENVIRONMENTAL BIOPHYSICS 52 ( 3 ) 389 - 395 2013年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

This paper provides absorbed doses arising from radon gas in air retained in lung airway lumens. Because radon gas exposure experiments often use small animals, the calculation was performed for mice and rats. For reference, the corresponding computations were also done for humans. Assuming that radon concentration in airway lumens is the same as that in the environment, its progeny's production in and clearance from airways were simulated. Absorbed dose rates were obtained for three lung regions and the whole lung, considering that secretory and basal cells are sensitive to radiation. The results showed that absorbed dose rates for all lung regions and whole lung generally increase from mice to rats to humans. For example, the dose rates for the whole lung were 25.4 in mice, 41.7 in rats, and 59.9 pGy (Bq m(-3))(-1) h(-1) in humans. Furthermore, these values were also compared with lung dose rates from two other types of exposures, that is, due to inhalation of radon or its progeny, which were already reported. It was confirmed that the direct inhalation of radon progeny in the natural environment, which is known as a cause of lung cancer, results in the highest dose rates for all species. Based on the present calculations, absorbed dose rates of the whole lung from radon gas were lower by a factor of about 550 (mice), 200 (rats), or 70 (humans) than those from radon progeny inhalation. The calculated dose rate values are comparatively small. Nevertheless, the present study is considered to contribute to our understanding of doses from inhalation of radon and its progeny.

DOI： 10.1007/s00411-013-0478-5

Preventive and curative effects of radon inhalation on chronic constriction injury-induced neuropathic pain in mice

K. Yamato, T. Kataoka, Y. Nishiyama, T. Taguchi, K. Yamaoka

EUROPEAN JOURNAL OF PAIN 17 ( 4 ) 480 - 492 2013年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

Background Radon therapy is clinically useful for the treatment of pain-related diseases. However, there have been no studies regarding the effects of radon inhalation on neuropathic pain. In this study, we aimed to determine whether radon inhalation actually induced a remission of neuropathic pain and improved the quality of life. Methods First, we investigated the antinociceptive effects of radon inhalation in the chronic constriction injury (CCI) model of neuropathic pain. We evaluated pain behaviour in mice before and after CCI surgery, using von Frey test. Pretreated mice received CCI surgery immediately after 24-h inhalation of radon at background (BG) concentration (c. 19Bq/m3), or at a concentration of 1000 or 2000Bq/m3, and post-treated mice inhaled similar levels of radon 2 days after CCI surgery. Results CCI surgery induced mechanical allodynia and hyperalgesia on a plantar surface of mice, as assessed using von Frey test, and 2000Bq/m3 radon inhalation alleviated hyperalgesic conditions 2237% compared to BG level concentration. Concurrently, CCI surgery increased norepinephrine (NE), tumour necrosis factor-alpha (TNF-) and nitric oxide (NO) concentrations in plasma, and leukocyte migration in paws. Furthermore, CCI-induced neuropathy reduced superoxide dismutase (SOD) activity. Treatment with radon inhalation, specifically at a concentration of 2000Bq/m3, produced antinociceptive effects, i.e., lowered plasma TNF-, NE and NO levels and restored SOD activity, as well as pain-related behaviour. Conclusions This study showed that inhalation of 2000Bq/m3 radon prevented and alleviated CCI-induced neuropathic pain in mice.

DOI： 10.1002/j.1532-2149.2012.00210.x

Antinociceptive Effects of Radon Inhalation on Formalin-Induced Inflammatory Pain in Mice

Keiko Yamato, Takahiro Kataoka, Yuichi Nishiyama, Takehito Taguchi, Kiyonori Yamaoka

INFLAMMATION 36 ( 2 ) 355 - 363 2013年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER/PLENUM PUBLISHERS

Radon therapy is clinically useful for the treatment of inflammatory diseases. The mechanisms of pain relief remain to be fully elucidated. In this study, we investigated the antinociceptive effects of radon inhalation in a mouse model of formalin-induced inflammatory pain. Immediately, after radon inhalation at a concentration of background level (ca. 19 Bq/m(3)), 1,000 or 2,000 Bq/m(3) for 24 h, 1.35 % formalin (0.5 % formaldehyde in saline, 20 mu l) was subcutaneously injected into the hind paw of mice, and we measured licking response time. Radon inhalation inhibited the second phase of response in formalin test. Formalin administration induced nociception and increased tumor necrosis factor alpha (TNF-alpha) and nitric oxide (NO) levels in serum and leukocyte migration in paws. Concurrently, formalin injection decreased antioxidative functions. Radon inhalation produced antinociceptive effects, i.e., lowered serum TNF-alpha and NO levels, and restored antioxidative functions. The results showed that radon inhalation inhibited formalin-induced inflammatory pain.

DOI： 10.1007/s10753-012-9554-2

Suppression of streptozotocin-induced type-1 diabetes in mice by radon inhalation

Y. Nishiyama, T. Kataoka, J. Teraoka, A. Sakoda, H. Tanaka, Y. Ishimori, F. Mitsunobu, T. Taguchi, K. Yamaoka

Physiological Research 62 ( 1 ) 57 - 66 2013年

記述言語：英語掲載種別：研究論文（学術雑誌）

We examined the protective effect of radon inhalation on streptozotocin (STZ)-induced type-1 diabetes in mice. Mice inhaled radon at concentrations of 1000, 2500, and 5500 Bq/m3 for 24 hours before STZ administration. STZ administration induced characteristics of type-1 diabetes such as hyperglycemia and hypoinsulinemia
however, radon inhalation at doses of 1000 and 5500 Bq/m3 significantly suppressed the elevation of blood glucose in diabetic mice. Serum insulin was significantly higher in mice pre-treated with radon at a dose of 1000 Bq/m3 than in mice treated with a sham. In addition, superoxide dismutase activities and total glutathione contents were significantly higher and lipid peroxide was significantly lower in mice pre-treated with radon at doses of 1000 and 5500 Bq/m3 than in mice treated with a sham. These results were consistent with the result that radon inhalation at 1000 and 5500 Bq/m3 suppressed hyperglycemia. These findings suggested that radon inhalation suppressed STZ-induced type-1 diabetes through the enhancement of antioxidative functions in the pancreas. © 2013 Institute of Physiology v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic.

ラドンの健康影響に関する一考察ラドン療法の効果と機構に関する最近の研究動向

西山祐一, 片岡隆浩, 山岡聖典

日本原子力学会和文論文誌 12 ( 4 ) 267 - 276 2013年

ラドン療法に関する最近の研究動向-鎮痛効果に着目して-

大和恵子, 片岡隆浩, 西山祐一, 山岡聖典

放射線生物研究 48 ( 1 ) 66 - 81 2013年

記述言語：日本語出版者・発行元：放射線生物研究会

ラドン療法は、疼痛性疾患・呼吸器疾患・消化器疾患・代謝性疾患などに対し改善効果があるとされている。しかし、これまでにラドン療法による改善効果について科学的に実証したデータは少なく、その機構の詳細な解明も必要とされている。適応症のうち欧州では特に効果度の高いとされる疼痛性疾患に対する治療が盛んに行われ、臨床試験により持続的な疼痛の軽減や鎮痛薬服用量の減少などが明らかにされつつある。筆者らも動物実験により、ラドン吸入による疼痛の軽減やこれを示す関連物質の変化などを明らかにしている。本稿では、このラドン療法に伴う鎮痛効果に関して、欧州における最近の研究動向や筆者らによる神経障害性疼痛・炎症性疼痛・炎症性浮腫などの緩和効果に関する研究について概説する。(著者抄録)

Study of Antioxidative Effects and Anti-inflammatory Effects in Mice due to Low-dose X-irradiation or Radon Inhalation

Journal of Radiation Research 54 ( 4 ) 587 - 596 2013年

Comparative study on the inhibitory effects of antioxidant vitamins and radon on carbon tetrachloride-induced hepatopathy

Takahiro Kataoka, Yuichi Nishiyama, Keiko Yamato, Junichi Teraoka, Yuji Morii, Akihiro Sakoda, Yuu Ishimori, Takehito Taguchi, Kiyonori Yamaoka

JOURNAL OF RADIATION RESEARCH 53 ( 6 ) 830 - 839 2012年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

We have previously reported that radon inhalation activates anti-oxidative functions and inhibits carbon tetrachloride (CCl4)-induced hepatopathy. It has also been reported that antioxidant vitamins can inhibit CCl4-induced hepatopathy. In the current study, we examined the comparative efficacy of treatment with radon, ascorbic acid and alpha-tocopherol on CCl4-induced hepatopathy. Mice were subjected to intraperitoneal injection of CCl4 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 alpha-tocopherol (100, 300, or 500 mg/kg bodyweight). We estimated the inhibitory effects on CCl4-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 alpha-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 CCl4 alone. These findings suggest that radon inhalation has an anti-oxidative effect against CCl4-induced hepatopathy similar to the anti-oxidative effects of ascorbic acid or alpha-tocopherol due to the induction of anti-oxidative functions.

DOI： 10.1093/jrr/rrs057

Lung dosimetry of inhaled radon progeny in mice

Akihiro Sakoda, Yuu Ishimori, Kosuke Fukao, Kiyonori Yamaoka, Takahiro Kataoka, Fumihiro Mitsunobu

RADIATION AND ENVIRONMENTAL BIOPHYSICS 51 ( 4 ) 425 - 442 2012年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Biological response of exposure to radon progeny has long been investigated, but there are only few studies in which absorbed doses in lungs of laboratory animals were estimated. The present study is the first attempt to calculate the doses of inhaled radon progeny for mice. For reference, the doses for rats and humans were also computed with the corresponding models. Lung deposition of particles, their clearance, and energy deposition of alpha particles to sensitive tissues were systematically simulated. Absorbed doses to trachea and bronchi, bronchioles and terminal bronchioles, alveolar-interstitial regions, and whole lung were first provided as a function of monodisperse radon progeny particles with an equilibrium equivalent radon concentration of 1 Bq m(-3) (equilibrium factor, 0.4 and unattached fraction, 0.01). Based on the results, absorbed doses were then calculated for (1) a reference mine condition and (2) a condition previously used for animal experiments. It was found that the whole lung doses for mice, rats, and humans were 34.8, 20.7, and 10.7 nGy (Bq m(-3))(-1) h(-1) for the mine condition, respectively, while they were 16.9, 9.9, and 6.5 nGy (Bq m(-3))(-1) h(-1) for the animal experimental condition. In both cases, the values for mice are about 2 times higher than those for rats, and about 3 times higher than those for humans. Comparison of our data on rats and humans with those published in the literature shows an acceptable agreement, suggesting the validity of the present modeling for mice. In the future, a more sophisticated dosimetric study of inhaled radon progeny in mice would be desirable to demonstrate how anatomical, physiological, and environmental parameters can influence absorbed doses.

DOI： 10.1007/s00411-012-0431-z

Radioactivity of Pb-210 in Japanese cigarettes and radiation dose from smoking inhalation

A. Sakoda, K. Fukao, A. Kawabe, T. Kataoka, K. Hanamoto, K. Yamaoka

RADIATION PROTECTION DOSIMETRY 150 ( 1 ) 109 - 113 2012年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

It is well known that cigarette tobaccos contain naturally occurring radioactive nuclides such as Pb-210 and Po-210. In many countries, the radioactivity of tobaccos has been measured to estimate the effective dose from smoking inhalation. The present study covered 24 cigarette brands including the top 20 of sales in Japan between April 2008 and March 2009. The activity concentrations of Pb-210 were measured by gamma-ray spectrometry, and then those of its progeny (Po-210) were evaluated assuming the radioactive equilibrium between the two nuclides. Their concentrations were in the range of 214 mBq cigarette(1) with an arithmetic mean of 83 mBq cigarette(1). The annual committed effective doses were also calculated, based on the scenario that a smoker consumes 20 cigarettes a day. The average doses from Pb-210 and Po-210 inhalations were 229 and 6827 Sv y(1), respectively.

DOI： 10.1093/rpd/ncr364

Protective Effects of Radon Inhalation on Carrageenan-Induced Inflammatory Paw Edema in Mice

Takahiro Kataoka, Junichi Teraoka, Akihiro Sakoda, Yuichi Nishiyama, Keiko Yamato, Mayuko Monden, Yuu Ishimori, Takaharu Nomura, Takehito Taguchi, Kiyonori Yamaoka

INFLAMMATION 35 ( 2 ) 713 - 722 2012年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER/PLENUM PUBLISHERS

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/m(3) 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-alpha) and nitric oxide in serum. However, radon inhalation significantly reduced carrageenan-induced paw edema. Serum TNF-alpha 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.

DOI： 10.1007/s10753-011-9364-y

Study on effects of thoron and thermal treatment for aging-related diseases in humans

Y. Aoyama, T. Kataoka, Sh. Nakagawa, A. Sakoda, Y. Ishimori, F. Mitsunobu, K. Yamaoka

IRANIAN JOURNAL OF RADIATION RESEARCH 9 ( 4 ) 221 - 229 2012年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IJRR-IRANIAN JOURNAL RADIATION RES

Background: The aim of this study was to analyze the effects of thoron and thermal treatment for aging-related diseases in humans. Materials and Methods: All subjects inhaled thoron with a high concentration (about 4900 Bq/m(3)) for 2 weeks. Blood pressures were measured and blood samples were collected after each treatment 1, 2 and 3 weeks after the first treatment. Results: The alpha-atrial natriuretic peptide level of the rheumatoid arthritis group was increased and the blood pressure was significantly decreased. Superoxide dismutase activity of rheumatoid arthritis group was significantly increased by treatment. In addition, thoron and thermal treatment significantly enhanced the concanavalin A-induced mitogen response and increased the level of CD4-positive cells; it decreased the level of CD8-positive cells. The results suggest that thoron and thermal treatment activates antioxidative function. Furthermore, these findings suggest that thoron and thermal treatment prevents diabetic ketoacidosis and contributes to the prevention of aging-related diseases. Conclusion: Thoron and thermal therapy may be part of the mechanism for the alleviation of diabetes mellitus and rheumatoid arthritis. Iran. J. Radiat. Res., 2012; 9(4): 221-229

Pressure dependence of X-rays produced by an LiTaO3 single crystal at low pressures

Katsumi Hanamoto, Atsushi Kawabe, Akihiro Sakoda, Takahiro Kataoka, Mari Okada, Kiyonori Yamaoka

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 669 ( 21 ) 66 - 69 2012年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

The energy spectra of X-rays produced by an LiTaO3 single crystal have been measured at pressures of 5-50 Pa. The energy spectra showed that the amount of X-rays increased exponentially and the endpoint energy of the spectra increased linearly with the decrease of pressure at pressures of 10-25 Pa. A maximum endpoint energy of about 22 key was obtained using an LiTaO3 single crystal with 0.5 mm thickness at the pressure of 10 Pa. The maximum energy produced by the present experimental setup was estimated assuming that the LiTaO3 single crystal forms a parallel-plate capacitor. The estimated energy reasonably agreed with the energy obtained. The pressure dependence of the endpoint energy was discussed in relation to the breakdown potential at low pressures. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nima.2011.12.028

Inhibitory Effects of Prior Low-dose X-irradiation on Cold-induced Brain Injury in Mouse

Masaaki Yoshimoto, Takahiro Kataoka, Teruaki Toyota, Takehito Taguchi, Kiyonori Yamaoka

INFLAMMATION 35 ( 1 ) 89 - 97 2012年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER/PLENUM PUBLISHERS

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.

DOI： 10.1007/s10753-011-9293-9

Comparative study on the inhibitory effects of α-tocopherol and radon on carbon tetrachloride-induced renal damage

Takahiro Kataoka, Keiko Yamato, Yuichi Nishiyama, Yuji Morii, Reo Etani, Yuji Takata, Katsumi Hanamoto, Atsuishi Kawabe, Akihiro Sakoda, Yuu Ishimori, Takehito Taguchi, Kiyonori Yamaoka

Renal Failure 34 ( 9 ) 1181 - 1187 2012年

Activation of bio-defense system by low-dose irradiation or radon inhalation and its applicable possibility for treatment of diabetes and hepatopathy

Takahiro Kataoka, Kiyonori Yamaoka

ISRN Endocrinology 2012 1 - 11 2012年

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

片岡隆浩, 徳永力三, 迫田晃弘, 川辺睦, 花元克巳, 山岡聖典

RADIOISOTOPES 61 ( 1 ) 1 - 8 2012年

Effects of pre and post radon inhalation on carbon tetrachloride-induced oxidative damage in mouse organs

Yuichi Nishiyama, Takahiro Kataoka, Junichi Teraoka, Akihiro Sakoda, Yuu Ishimori, Kiyonori Yamaoka

RADIOISOTOPES 61 ( 5 ) 231 - 241 2012年

Inhibitory Effects of Pretreatment with Radon on Acute Alcohol-Induced Hepatopathy in Mice

Teruaki Toyota, Takahiro Kataoka, Yuichi Nishiyama, Takehito Taguchi, Kiyonori Yamaoka

MEDIATORS OF INFLAMMATION 2012 ( Article ID 382801 ) 1 - 10 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：HINDAWI PUBLISHING CORPORATION

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.

DOI： 10.1155/2012/382801

Suppression of Dextran Sulfate Sodium-Induced Colitis in Mice by Radon Inhalation

Yuichi Nishiyama, Takahiro Kataoka, Keiko Yamato, Takehito Taguchi, Kiyonori Yamaoka

MEDIATORS OF INFLAMMATION 2012 ( Article ID 239617 ) 1 - 11 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：HINDAWI LTD

The enhanced release of reactive oxygen species from activated neutrophils plays important role in the pathogenesis of inflammatory bowel disease. We previously reported that radon inhalation activates antioxidative functions in various organs of mice. In this study, we examined the protective effects of radon inhalation on dextran sulfate sodium- (DSS) induced colitis in mice which were subjected to DSS for 7 days. Mice were continuously treated with air only (sham) or radon at a concentration of 2000 Bq/m(3) from a day before DSS administration to the end of colitis induction. In the results, radon inhalation suppressed the elevation of the disease activity index score and histological damage score induced by DSS. Based on the changes in tumor necrosis factor-alpha in plasma and myeloperoxidase activity in the colon, it was shown that radon inhalation suppressed DSS-induced colonic inflammation. Moreover, radon inhalation suppressed lipid peroxidation of the colon induced by DSS. The antioxidant level (superoxide dismutase and total glutathione) in the colon after DSS administration was significantly higher in mice treated with radon than with the sham. These results suggested that radon inhalation suppressed DSS-induced colitis through the enhancement of antioxidative functions in the colon.

DOI： 10.1155/2012/239617

Radon Inhalation Protects Mice from Carbon-Tetrachloride-Induced Hepatic and Renal Damage

Takahiro Kataoka, Yuichi Nishiyama, Teruaki Toyota, Masaaki Yoshimoto, Akihiro Sakoda, Yuu Ishimori, Yutaka Aoyama, Takehito Taguchi, Kiyonori Yamaoka

INFLAMMATION 34 ( 6 ) 559 - 567 2011年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER/PLENUM PUBLISHERS

We assessed whether radon inhalation provided protection from carbon tetrachloride (CCl4)-induced hepatic and renal damage in mice. Mice were subjected to intraperitoneal injection of CCl4 after inhaling approximately 18 kBq/m(3) radon for 6 h. Radon inhalation significantly increased total glutathione (t-GSH) content and glutathione peroxidase (GPx) activity in the liver and kidney. Injection of CCl4 was associated with significantly higher levels of glutamic oxaloacetic transaminase (GOT) and alkaline phosphatase (ALP) activity and creatinine level in serum, and pretreatment with radon significantly decreased the GOT and ALP activity and creatinine level associated with CCl4 injection, suggesting that radon inhalation alleviates CCl4-induced hepatic and renal damage. The t-GSH contents and GPx activity in the liver and kidney of animals pretreated with radon were significantly higher than those of the CCl4-only group. These findings suggested that radon inhalation activated antioxidative functions and inhibited CCl4-induced hepatic and renal damage in mice.

DOI： 10.1007/s10753-010-9263-7

Study of the Response of Superoxide Dismutase in Mouse Organs to Radon Using a New Large-scale Facility for Exposing Small Animals to Radon

Takahiro Kataoka, Akihiro Sakoda, Yuu Ishimori, Teruaki Toyota, Yuichi Nishiyama, Hiroshi Tanaka, Fumihiro Mitsunobu, Kiyonori Yamaoka

JOURNAL OF RADIATION RESEARCH 52 ( 6 ) 775 - 781 2011年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JAPAN RADIATION RESEARCH SOC

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/m(3) for 0.5, 1, 2, 4, or 8 days. When mice were exposed to radon at 2000 day.Bq/m(3), 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.

DOI： 10.1269/jrr.10072

PERFORMANCE OF THE FIRST JAPANESE LARGE-SCALE FACILITY FOR RADON INHALATION EXPERIMENTS WITH SMALL ANIMALS

Yuu Ishimori, Fumihiro Mitsunobu, Kiyonori Yamaoka, Hiroshi Tanaka, Takahiro Kataoka, Akihiro Sakoda

RADIATION PROTECTION DOSIMETRY 146 ( 1-3 ) 31 - 33 2011年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

A radon test facility for small animals was developed in order to increase the statistical validity of differences of the biological response in various radon environments. This paper illustrates the performances of that facility, the first large-scale facility of its kind in Japan. The facility has a capability to conduct approximately 150 mouse-scale tests at the same time. The apparatus for exposing small animals to radon has six animal chamber groups with five independent cages each. Different radon concentrations in each animal chamber group are available. Because the first target of this study is to examine the in vivo behaviour of radon and its effects, the major functions to control radon and to eliminate thoron were examined experimentally. Additionally, radon progeny concentrations and their particle size distributions in the cages were also examined experimentally to be considered in future projects.

DOI： 10.1093/rpd/ncr100

STUDIES ON POSSIBILITY FOR ALLEVIATION OF LIFESTYLE DISEASES BY LOW-DOSE IRRADIATION OR RADON INHALATION

Takahiro Kataoka, Akihiro Sakoda, Masaaki Yoshimoto, Shinya Nakagawa, Teruaki Toyota, Yuichi Nishiyama, Keiko Yamato, Yuu Ishimori, Atsushi Kawabe, Katsumi Hanamoto, Takehito Taguchi, Kiyonori Yamaoka

RADIATION PROTECTION DOSIMETRY 146 ( 1-3 ) 360 - 363 2011年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

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 (CCl(4)) administration. Results showed that radon inhalation alleviates CCl(4)-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.

DOI： 10.1093/rpd/ncr189

An Assessment of Radioactivity Levels of Pb-210 and K-40 in Tobacco and Radiation Exposure from Smoking

Tomohiro Nagamatsu, Akihiro Sakoda, Takahiro Kataoka, Toshiro Ono, Kiyonori Yamaoka

ACTA MEDICA OKAYAMA 65 ( 2 ) 91 - 95 2011年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OKAYAMA UNIV MED SCHOOL

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 Pb-210 and K-40 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 Pb-210 and K-40 in the cigarette tobacco were 0.01 and 0.3 Bq/cigarette. Since this Pb-210 activity and the Po-210 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 Pb-210 (12%) into smoke was almost the same as that of K-40 (15%), whereas the reported value for Po-210 (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 Pb-210 and Po-210. 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.

DOI： 10.18926/AMO/45267

A comparative study on effect of continuous radon inhalation on several-time acute alcohol-induced oxidative damages of liver and brain in mouse

Takahiro Kataoka, Akihiro Sakoda, Masaaki Yoshimoto, Teruaki Toyota, Yuki, Yamamoto, Yuu Ishimori, Katsumi Hanamoto, Atsushi Kawabe, Fumihiro Mitsunobu, Kiyonori Yamaoka

Radiation Safety Management 10 ( 1 ) 1 - 7 2011年

Applicability and performance of an imaging plate at subzero temperatures

Akihiro Sakoda, Yuu Ishimori, Katsumi Hanamoto, Atsushi Kawabe, Takahiro Kataoka, Tomohiro Nagamatsu, Kiyonori Yamaoka

APPLIED RADIATION AND ISOTOPES 68 ( 10 ) 2013 - 2015 2010年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The performance of imaging plates (IPs) has not been studied at temperatures lower than 0 degrees C. In the present study, an IP was irradiated with gamma rays emitted from the mineral monazite at temperatures between -80 and 30 degrees C to determine its fundamental properties. The IP response as a function of irradiation time was found to be linear, suggesting that the IP works properly at low temperatures. Fading, an effect which should be considered at temperatures of more than 0 degrees C, was not observed at -30 and 80 degrees C. Furthermore, the fading-corrected PSL value of the IP irradiated at 80 degrees C was lower than at other temperatures (30.5 and -30 degrees C). This can be explained by thermostimulated luminescence (TSL). Since the only intensive TSL peak in the temperature range from -80 to 30 degrees C is present at about -43 degrees C, some of the electrons trapped at F centers recombine with holes through the process of TSL before the stored radiation image is read out at room temperature. This finding suggests that the apparent sensitivity of the IP is lower at -80 degrees C although it is similar to sensitivities between -30 and 30 degrees C. This low sensitivity should be corrected to perform quantitative measurements. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.apradiso.2010.03.020

Physiologically Based Pharmacokinetic Modeling of Inhaled Radon to Calculate Absorbed Doses in Mice, Rats, and Humans

Akihiro Sakoda, Yuu Ishimori, Atsushi Kawabe, Takahiro Kataoka, Katsumi Hanamoto, Kiyonori Yamaoka

JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY 47 ( 8 ) 731 - 738 2010年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

This is the first report to provide radiation doses, arising from inhalation of radon itself, in mice and rats. To quantify absorbed doses to organs and tissues in mice, rats, and humans, we computed the behavior of inhaled radon in their bodies on the basis of a physiologically based pharmacokinetic (PBPK) model. It was assumed that radon dissolved in blood entering the gas exchange compartment is transported to any tissue by the blood circulation to be instantaneously distributed according to a tissue/blood partition coefficient. The calculated concentrations of radon in the adipose tissue and red bone marrow following its inhalation were much higher than those in the others, because of the higher partition coefficients. Compared with a previous experimental data for rats and model calculation for humans, the present calculation was proved to be valid. Absorbed dose rates to organs and tissues were estimated to be within the range of 0.04-1.4 nGy (Bq m(-3))(-1) day(-1) for all the species. Although the dose rates are not so high, it may be better to pay attention to the dose to the red bone marrow from the perspective of radiation protection. For more accurate dose assessment, it is necessary to update tissue/blood partition coefficients of radon that strongly govern the result of the PBPK modeling.

DOI： 10.1080/18811248.2010.9711649

First model of the effect of grain size on radon emanation

Akihiro Sakoda, Katsumi Hanamoto, Yuu Ishimori, Takahiro Kataoka, Atsushi Kawabe, Kiyonori Yamaoka

APPLIED RADIATION AND ISOTOPES 68 ( 6 ) 1169 - 1172 2010年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The present model represents an improvement on previous models of radon emanation from soil by incorporating soil grain size in addition to moisture. Monte Carlo simulation was employed in the calculation since it was difficult to mathematically express the radon emanation fraction for the present soil model. Grain size is one of the most important factors in describing the properties of soil. Grain size was demonstrated to affect the radon emanation fraction, depending on moisture content. Although the emanation fraction is generally considered to be proportional to grain size, the result of the model calculation suggested that the effect of grain size is not so simple. This study should serve as an initial step toward improving the modeling of this radon emanation. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.apradiso.2009.11.070

Differences of natural radioactivity and radon emanation fraction among constituent minerals of rock or soil

Akihiro Sakoda, Yuichi Nishiyama, Katsumi Hanamoto, Yuu Ishimori, Yuki Yamamoto, Takahiro Kataoka, Atsushi Kawabe, Kiyonori Yamaoka

APPLIED RADIATION AND ISOTOPES 68 ( 6 ) 1180 - 1184 2010年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

We examined differences in the radioactive characteristics among the main minerals forming granite materials. Using a non-toxic high-density agent, minerals were separated from rock (granite-gneiss) and soil (weathered granite) samples. The natural radioactivity ((238)U and (226)Ra) and radon emanation fraction of the minerals were then studied by gamma-ray spectrometry. The radon emanation fractions (27-43%) of the minerals from the soil were much higher than those (0.6-4.6%) of the rock minerals. Additionally, the emanation fractions differed greatly among the minerals separated from both the bulk rock and soil. These results were discussed in terms of the differences of surface area and radium distribution in the mineral grains. It was noticeable that a higher emanation fraction than expected for quartz was commonly observed in the rock and soil samples. We then estimated the contribution of each constituent mineral to the total radon exhalation from the bulk samples. The result depended not only on the radon emanation fraction, but also on the (226)Ra activity and the mineral content. Furthermore, using the obtained data, we also discussed the effect of grain size on radon emanation and why this has been reported to vary markedly in previous studies. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.apradiso.2009.12.036

Experimental and modeling studies of grain size and moisture content effects on radon emanation

Akihiro Sakoda, Yuu Ishimori, Katsumi Hanamoto, Takahiro Kataoka, Atsushi Kawabe, Kiyonori Yamaoka

RADIATION MEASUREMENTS 45 ( 2 ) 204 - 210 2010年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Some models have already been developed to explain the effect of moisture content on the radon emanation fraction of soil. For this purpose, "microscopic" soil models, which are easy to deal with mathematically but cannot take grain size into consideration, have been designed. These previous models consist basically of two opposite grain surfaces and pores between the grains. In the present study, in order to study the effect of not only moisture content but also grain size, we present a simple modeling approach based on two "macroscopic" soil models: (1) a single-grain model and (2) a multiple-grain model. The latter model represents a configuration of spherical grains packed in a simple cubic structure. Based on these soil models and general assumptions, the radon emanation fraction was calculated as a function of grain size or moisture content by Monte Carlo simulation. The results for the multiple-grain model show that the radon emanation fraction is markedly increased with grain sizes ranging from 10 to 100 inn and reaches a constant value of 50% when moisture content is 0% and the radium is uniformly distributed on the grain surface. Moreover, a drastic increase is seen at smaller grain sizes with increasing moisture content. From these results, we concluded that the calculation of radon emanation depends greatly on the pore size between a Ra-bearing grain and a neighboring grain. The validity of the model was also evaluated by comparison to experimental data. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.radmeas.2010.01.010

Development of a radon test facility for small animals

Yuu Ishimori, Fumihiro Mitsunobu, Kiyonori Yamaoka, Hiroshi Tanaka, Takahiro Kataoka, Akihiro Sakoda

保健物理 45 ( 1 ) 65 - 71 2010年

小動物病院におけるX線撮影に伴う放射線診療従事者の実効線量評価

川辺睦, 山田一孝, 花元克巳, 迫田晃弘, 片岡隆浩, 山岡聖典

動物臨床医学 19 ( 4 ) 113 - 117 2010年

記述言語：日本語出版者・発行元：動物臨床医学会

獣医療でX線撮影を実施するにあたっては，獣医療診療従事者等（獣医師および動物看護師，以下従事者等とする）による用手保定が必要になることが多い。このため，多くの検査で遠隔操作が可能な人間医療より従事者等の被ばくが高くなる可能性がある。しかしながら，これまでわが国における従事者等の被ばくに関する報告はほとんど見あたらず，正確な実態をつかめないのが現状である。また，体幹部防護衣を着用した従事者等は不均等被ばくの様態を呈し，測定基本部位のみのモニタリングでは実効線量を過小評価するおそれがある。そこで本研究では，一般的なX線撮影を用手保定法により行うときの従事者等の被ばくを，体幹部防護衣着用の前提で実効線量により評価した。その結果，90 kV，4 mAsで体厚20 cm程度の動物を撮影するときの従事者等の実効線量は約2.4 μSvとなり，1週間につき160回程度の撮影で年間の線量限度に達する見込みであることがわかった。

DOI： 10.11252/dobutsurinshoigaku.19.113

Basic Study on Active Changes in Biological Function of Mouse Liver Graft in Cold Storage after Low-Dose X-Irradiation

Takahiro Kataoka, Masaaki Yoshimoto, Shinya Nakagawa, Yuko Mizuguchi, Takehito Taguchi, Kiyonori Yamaoka

JOURNAL OF CLINICAL BIOCHEMISTRY AND NUTRITION 45 ( 2 ) 219 - 226 2009年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JOURNAL CLINICAL BIOCHEMISTRY & NUTRITION

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.

DOI： 10.3164/jcbn.09-06

No different sensitivity in terms of whole-body irradiation between normal and acatalasemic mice

Shinya Nakagawa, Takahiro Kataoka, Yuko Mizuguchi, Masaaki Yoshimoto, Akihiro Sakoda, Takaharu Nomura, Da-Hong Wang, Atsushi Kawabe, Takehito Taguchi, Kiyonori Yamaoka

JOURNAL OF CLINICAL BIOCHEMISTRY AND NUTRITION 43 ( 1 ) 41 - 49 2008年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JOURNAL CLINICAL BIOCHEMISTRY & NUTRITION

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.

DOI： 10.3164/jcbn.2008042

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.

中川慎也, 片岡隆浩, 迫田晃弘, 石森有, 花元克巳, 山岡聖典

RADIOISOTOPES 57 ( 4 ) 241 - 251 2008年

Inhibitory effects of prior low-dose X-irradiation on ischemia-reperfusion injury in mouse paw

Takahiro Kataoka, Yuko Mizuguchi, Masaaki Yoshimoto, Takehito Taguchi, Kiyonori Yamaoka

JOURNAL OF RADIATION RESEARCH 48 ( 6 ) 505 - 513 2007年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

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 I hr after reperfusion from ischemia for I 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 I 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.

DOI： 10.1269/jrr.07060

Basic study on biochemical mechanism of thoron and thermal therapy

Takahiro Kataoka, Yutaka Aoyama, Akihiro Sakoda, Shinya Nakagawa, Kiyonori Yamaoka

Physiological Chemistry and Physics and Medical NMR 38 ( 2 ) 85 - 92 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）

Exposure to water in hot springs containing thoron is thought to exercise beneficial effects on hypertension and diabetes mellitus. To put to a test this hypothesis we examined the time dependent changes in the levels of lipid peroxide, vasoactive- and diabetes associated substances in human blood in order to throw further light on the possible beneficial influence of thoron and thermal therapy on the mechanism of hypertension and diabetes mellitus. Every 2 days, nasal inhalation of vapor containing thoron was performed for 40 min. Blood samples were collected after each treatment at 1,2, and 3 weeks after the first treatment. Results show that the treatment decreased the lipid peroxide levels. The finding suggests that the treatment contributes to the prevention of peroxidation reaction related to hypertension and diabetes mellitus. Moreover, the changes in vasoactive-associated substances indicate an increase in tissue perfusion, suggesting that the treatment plays a role in alleviating hypertension. The treatment decreased the total ketone body levels and the finding suggests that the treatment contributes to the prevention of diabetes mellitus related to the insulin deficiency.

Histological changes in spleens of radio-sensitive and radio-resistant mice exposed to low-dose X-ray irradiation

Takahiro Kataoka, Yuko Mizuguchi, Kenji Notohara, Takehito Taguchi, Kiyonori Yamaoka

Physiological Chemistry and Physics and Medical NMR 38 ( 1 ) 21 - 29 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）

We have previously determined by using immune-assay or bio-assay methods that low-dose irradiation enhances immune and anti-oxidation functions. In this study, we examined histological changes of lymphatic follicles at 4, 24, or 48 hrs after sham, 0.25, 0.5, or 15 Gy irradiation in the spleens of BALB/c mice, which are sensitive to radiation compared with other strains, and C57BL/6J mice, which are resistant to radiation, using hematoxylin-eosin staining for lymphatic follicles or methylgreen pyronin staining for plasma cells. Results show that the lymphatic follicles in the spleens of the two mouse strains decreased at 24 or 48 hrs after 15 Gy irradiation. The number of plasma cells in the spleens of sham irradiated BALB/c mice was greater than that of sham irradiated C57BL/6J mice. At 4 hrs after 0.25 Gy irradiation, plasma cells increased in the spleens of the two mouse strains. These findings suggest, by histology, that low-dose irradiation activates the plasma cells and enhances the immune function. Although those two mouse strains have different sensitivities to radiation, the above changes were similar in both time course and degree of response. Therefore, the phenomena observed may be common in mice.

The elevation of p53 protein level and SOD activity in the resident blood of the Misasa radon hot spring district

K Yamaoka, F Mitsunobu, S Kojima, M Shibakura, T Kataoka, K Hanamoto, Y Tanizaki

JOURNAL OF RADIATION RESEARCH 46 ( 1 ) 21 - 24 2005年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JAPAN RADIATION RESEARCH SOC

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.

DOI： 10.1269/jrr.46.21

Effects of post low-dose X-ray irradiation on carbon tetrachloride-induced acatalasemic mice liver damage

Takahiro Kataoka, Takaharu Nomura, Da-Hong Wang, Takehito Taguchi, Kiyonori Yamaoka

Physiological Chemistry and Physics and Medical NMR 37 ( 2 ) 109 - 126 2005年

記述言語：英語掲載種別：研究論文（学術雑誌）

The catalase activities in the blood and organs of the acatalasemic (C3H/AnLCsb-Csb) mouse of the C3H strain are lower than those of the normal (C3H/AnLCsa-Csa) mouse. We examined the effects of post low-dose (0.5 Gy) X-ray irradiation which reduced the oxidative damage under carbon tetrachloride-induced hepatopathy in acatalasemic or normal mice. As a result, the 0.5 Gy irradiation after carbon tetrachloride administration decreased the glutamic oxaloacetic and glutamic pyruvic transaminase activity in the acatalasemic mouse blood to a level similar to that of the acatalasemic mouse blood not treated with carbon tetrachloride
this is in contrast to a high-dose (15 Gy) irradiation. In the same manner, pathological disorder was improved by 0.5 Gy irradiation. The fat degeneration in normal mice was quickly reduced, in contrast to acatalasemic mice. These findings suggest that low-dose irradiation after carbon tetrachloride administration accelerates the rate of recovery and that catalase plays an important role in the recovery from hepatopathy induced by carbon tetrachloride, in contrast to high-dose irradiation.

人工トロン温泉由来の放射能と負イオン(マイナスイオン)の諸特性

迫田晃弘, 片岡隆浩, 花元克巳, 山岡聖典

RADIOISOTOPES 54 ( 9 ) 375 - 383 2005年

Inhibitory effects of prior low-dose X-ray irradiation on carbon tetrachloride-induced hepatopathy in acatalasemic mice

K Yamaoka, T Kataoka, T Nomura, T Taguchi, DH Wang, S Mori, K Hanamoto, S Kira

JOURNAL OF RADIATION RESEARCH 45 ( 1 ) 89 - 95 2004年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JAPAN RADIATION RESEARCH SOC

The catalase activities in blood and organs of the acatalasemic (C3H/AnLCs(b)Cs(b)) mouse of C3H strain are lower than those of the normal (C3H/AnLCs(a)Cs(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.

DOI： 10.1269/jrr.45.89

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