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

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

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

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

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

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

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

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

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

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

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

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

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 13 2 2003 MRIにおける画像の再構成 77 82 EN Hirokazu Kato Katsumi Hanamoto Masahiro Kuroda Koichi Shibuya Shoji Kawasaki 10.18926/15215 磁気共鳴は医学におけるイメージングにおいて重要なモダリティーであり,高度な数学的手法が画像の再構成に取り入れられている｡画像再構成の数学的手法および画像再構成にいたるまでの数学的な過程を理解するこは,MRIを学ぶものにとって非常に重要であるが,成書において明確な説明はなされていない｡ここでは,MR画像の再構成法を,複素関数と複素フ-リェ係数を用いて導いたので報告する｡ No potential conflict of interest relevant to this article was reported.

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

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 14 2 2004 MRIにおけるサンプリング時間の測定と画像の再構成 121 128 EN Hirokazu Kato Katsumi Hanamoto Shoji Kawasaki Koichi Shibuya Masahiro Kuroda Tadashi Koyama 10.18926/15198 MRIにおいてk-spaceを構築するためにはエコー信号をサンプリング時間に従って採取する必要がある.このサンプリング時間を測定するために,FOV(field of view)の左半分にファントムを置くことにより階段関数となるスピン分布を生成した｡得られたエコー信号を,階段関数をフ-リェ変換したときに得られるフ-リェ係数と比較することによりサンプリング時間を求めた｡得られたサンプリング時間を用いて,MRI MULTI-TEST PHANTOMをMRI装置でスキャンすることにより得られたエコー信号をサンプリングしk-spaceを構築した。このk-spaceをフ-リェ逆変換することによりMRI MULTI-TEST PHANTOMの画像を再構成することができた。 No potential conflict of interest relevant to this article was reported.

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

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