Updated on 2024/12/27

写真a

 
NAKA Shuuhei
 
Organization
Faculty of Medicine, Dentistry and Pharmaceutical Sciences Associate Professor
Position
Associate Professor
External link

Degree

  • 博士(歯学) ( 2012.3   大阪大学 )

  • ph.D. (Dentistry) ( Osaka University )

Research Interests

  • Non-alcoholic steatohepatitis

  • IgA nephropathy

  • コラーゲン結合タンパク(Cnm)

  • 齲蝕原性細菌

  • Streptococcus mutans

  • 小児における侵襲性歯周炎

Research Areas

  • Life Science / Social dentistry

  • Life Science / Applied microbiology

  • Life Science / Developmental dentistry

Education

  • 大阪大学大学院歯学研究科(小児歯科学分野)    

    2008.4 - 2012.3

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  • Osaka University   大学院歯学研究科   小児歯科

    2008.4 - 2012.3

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    Country: Japan

  • 福岡歯科大学 歯学部 歯学科    

    2000.4 - 2006.3

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  • Fukuoka Dental College   歯学部   歯学科

    2000.4 - 2006.3

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    Country: Japan

  • 私立照曜館高等学校    

    1996.4 - 1999.3

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Research History

  • 岡山大学学術研究院医歯薬学域 准教授

    2024.4

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  • 岡山大学病院小児歯科 講師

    2017.2 - 2024.3

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  • 大阪大学大学院歯学研究科 助教(小児歯科学教室)   助教

    2014.11 - 2017.1

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  • Osaka University   大学院歯学研究科   Assistant Professor

    2014.11 - 2017.1

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    Country:Japan

  • 大阪大学歯学部附属病院 医員(小児歯科)

    2012.4 - 2014.10

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  • 大阪大学歯学部附属病院 医員(研修医)

    2008.4 - 2009.3

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Professional Memberships

  • 岡山歯学会 会員

    2019.10

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  • 日本小児歯科学会 会員

    2014.3 - 2024.3

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  • International Association for Dental Resarch (IADR) 会員

    2010.4

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  • 国際歯科研究学会日本部会 (JADR) 会員

    2010.4

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Committee Memberships

  •   岡山歯学会評議員  

    2024.4   

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  •   鎮静・鎮痛管理委員会委員  

    2023.9   

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  •   歯科用チェアユニット仕様策定委員会委員  

    2023.4   

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  •   歯科経営委員会委員  

    2023.4   

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  •   歯科系外来長連絡協議会委員  

    2023.4   

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  •   日本小児歯科学会中四国地方会幹事  

    2022.4   

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  •   医療材料選定会議委員  

    2022.4   

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  •   歯学部棟改修分野代表者  

    2022.4   

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  •   デジタル歯学教育部会委員  

    2022.4   

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  • 学内・研究科内での委員会   デジタル歯学教育部会委員  

    2022.4   

  • 学内・研究科内での委員会   歯学部棟改修分野代表者(小児歯科)  

    2020.4   

  • 学内・研究科内での委員会   自然生命科学研究支援センター動物資源部門鹿田施設利用協議会議会委員  

    2020.4   

  •   動物資源部門鹿田施設利用協議会委員  

    2019.4   

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  •   化学物質管理担当者  

    2019.4   

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  • 学内・研究科内での委員会   病院紹介ビデオワーキンググループ委員  

    2019.4 - 2020.3   

  • 公益社団法人日本小児歯科学会 英文誌編集委員   英文誌編集委員  

    2018.6   

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    Committee type:Academic society

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  • 日本小児歯科学会   英文誌編集委員会  

    2018.6   

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    Committee type:Academic society

  • 公益社団法人日本小児歯科学会   代議員  

    2018.4   

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  • 学内・研究科内での委員会   化学物質管理担当者  

    2018.4   

  • 日本小児歯科学会   日本小児歯科学会代議員  

    2018.4   

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    Committee type:Academic society

  •   国際担当部会委員  

    2018.4 - 2022.3   

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  • 学内・研究科内での委員会   国際担当部会委員  

    2018.4 - 2022.3   

  • 学内・研究科内での委員会   歯学部動物実験施設代表者  

    2017.4   

  • 学内・研究科内での委員会   岡山大学病院歯科医師卒後臨床研修管理委員会委員  

    2017.4   

  • 学内・研究科内での委員会   公募問題作成部会委員  

    2017.4   

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    部会長(2019年度)

  • 学内・研究科内での委員会   病院(歯科)改修に関する若手ワーキンググループ委員  

    2017.4 - 2019   

  • 学内・研究科内での委員会   歯学部先端領域研究センター運営会委員  

    2017.4 - 2018.3   

  •   公募問題作成部会委員  

    2017.2   

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  •   岡山大学病院歯科医師卒後臨床研修管理委員会委員  

    2017.2   

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  •   歯学部動物実験施設代表者  

    2017.2   

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Papers

  • Relationship Between the Presence of Red Complex Species and the Distribution of Other Oral Bacteria, Including Major Periodontal Pathogens in Older Japanese Individuals

    Mariko Kametani, Yasuyuki Nagasawa, Momoko Usuda, Ami Kaneki, Masashi Ogawa, Kensaku Shojima, Hiromitsu Yamazaki, Kana Tokumoto, Daiki Matsuoka, Kana Suehara, Yuto Suehiro, Tatsuya Akitomo, Chieko Mitsuhata, Taro Misaki, Seigo Ito, Shuhei Naka, Michiyo Matsumoto-Nakano, Kazuhiko Nakano, Hiromitsu Kishimoto, Ken Shinmura, Ryota Nomura

    International Journal of Molecular Sciences   25 ( 22 )   12243 - 12243   2024.11

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    Publishing type:Research paper (scientific journal)   Publisher:MDPI AG  

    Red complex bacteria (Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia) have high virulence in periodontal disease. In the present study, we aimed to elucidate the detailed symbiotic relationships between the red complex and other oral bacteria in older Japanese individuals. Polymerase chain reaction was performed using dental plaque from 116 subjects and specific primers for ten periodontal pathogens. The detection rate of Prevotella intermedia and Capnocytophaga sputigena was significantly higher in P. gingivalis-positive subjects than in P. gingivalis-negative subjects (p < 0.05). The detection rate of Campylobacter rectus, Prevotella nigrescens, Capnocytophaga ochracea, and Eikenella corrodens was significantly higher in T. forsythia-positive subjects than in T. forsythia-negative subjects (p < 0.01). In a comprehensive analysis of oral microbiomes, three red complex species-positive subjects had significantly higher α-diversity than only P. gingivalis-positive subjects (p < 0.05) and had significantly lower β-diversity than only T. forsythia-positive subjects (p < 0.01). In the taxonomy analysis, Porphyromonas was significantly higher in three red complex species-positive subjects than in only P. gingivalis-positive and only T. forsythia-positive subjects (p < 0.01). These results suggest that each red complex species forms a unique oral microbiome and individuals positive for all red complex bacteria may harbor oral bacteria that confer a significant advantage in developing periodontal disease.

    DOI: 10.3390/ijms252212243

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  • Contribution of collagen-binding protein Cnm of Streptococcus mutans to induced IgA nephropathy-like nephritis in rats. International journal

    Shuhei Naka, Daiki Matsuoka, Taro Misaki, Yasuyuki Nagasawa, Seigo Ito, Ryota Nomura, Kazuhiko Nakano, Michiyo Matsumoto-Nakano

    Communications biology   7 ( 1 )   1141 - 1141   2024.9

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    Language:English   Publishing type:Research paper (scientific journal)  

    IgA nephropathy (IgAN), the most common primary glomerulonephritis, is considered an intractable disease with unknown pathogenic factors. In our previous study, Streptococcus mutans, the major causative bacteria of dental caries, which expresses Cnm, was related to the induction of IgAN-like nephritis. In the present study, the Cnm-positive S. mutans parental strain, a Cnm-defective isogenic mutant strain, its complementation strain, and recombinant Cnm (rCnm) protein were administered intravenously to Sprague Dawley rats, and the condition of their kidneys was evaluated focusing on the pathogenicity of Cnm. Rats treated with parental and complement bacterial strains and rCnm protein developed IgAN-like nephritis with mesangial proliferation and IgA and C3 mesangial deposition. Scanning immunoelectron microscopy revealed that rCnm was present in the electron-dense deposition area of the mesangial region in the rCnm protein group. These results demonstrated that the Cnm protein itself is an important factor in the induction of IgAN in rats.

    DOI: 10.1038/s42003-024-06826-x

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  • High-performance silica-containing professional mechanical tooth-cleaning paste that effectively adsorbs pigments

    Tatsuya Akitomo, Satoru Kusaka, Mariko Kametani, Chieko Mitsuhata, Shuhei Naka, Michiyo Matsumoto-Nakano, Kazuhiko Nakano, Ryota Nomura

    Pediatric Dental Journal   34 ( 2 )   62 - 69   2024.8

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    Introduction: Pastes for professional mechanical tooth cleaning (PMTC) that contain abrasive ingredients can damage the surface of a tooth. A PMTC paste containing silica was recently developed as an adsorption material. Materials and methods: We assessed the effectiveness with regard to on stain deposition of a novel PMTC paste containing high-performance silica (HPS) comprising porous ultra-fine particles. We also compared the pigment adsorption capability of HPS with that of ordinary silica. Results: When PMTC solutions were added to hydrated lime stained with coffee or rooibos tea, a PMTC solution containing HPS was more effective with regard to stain removal than other PMTC solutions without HPS. In addition, stain-preventive effect of the PMTC paste containing HPS was also higher than that of the PMTC paste without HPS. When HPS and ordinary silica were immersed in food-coloring additives, HPS was more adasorptive than ordinary silica, especially with regard to high-molecular-weight pigments. Furthermore, HPS was significantly more adsorptive than ordinary silica 5 min after exposure to coffee and 24 h after exposure to rooibos tea (P < 0.05). Conclusion: Our results suggest that PMTC paste containing HPS effectively adsorbs pigments and can remove staining and prevent stain deposition without polishing teeth.

    DOI: 10.1016/j.pdj.2024.03.004

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  • IgA腎症患者と習慣性扁桃炎患者の摘出扁桃における歯周病菌の検出率の比較

    長澤 康行, 野村 良太, 三崎 太郎, 伊藤 誓悟, 山崎 博充, 庄嶋 健作, 松岡 大貴, 仲 周平, 仲野 道代, 新村 健, 仲野 和彦

    日本腎臓学会誌   66 ( 4 )   591 - 591   2024.6

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  • う蝕原性細菌cnm陽性Streptococcus mutansは扁桃を介してIgA腎症を増悪させる

    伊藤 誓悟, 三崎 太郎, 長澤 康行, 松岡 大貴, 仲 周平, 野村 良太, 仲野 道代, 仲野 和彦

    日本腎臓学会誌   66 ( 4 )   637 - 637   2024.6

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  • 非アルコール性脂肪肝炎発症に関連する鉄存在下でのStreptococcus mutansの性状変化の検討

    中野 聡大, 田畑 佳子, 仲 周平, 仲野 道代

    小児歯科学雑誌   62 ( 大会抄録号 )   151 - 151   2024.4

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  • 非アルコール性脂肪肝炎患者由来Streptococcus mutansの各臓器における分布とその特性に関する検討

    田畑 佳子, 仲 周平, 中野 聡大, 仲野 道代

    小児歯科学雑誌   62 ( 大会抄録号 )   121 - 121   2024.4

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  • 日本人小児口腔におけるStreptococcus mutansの陽性率と齲蝕経験歯数との関連の評価

    奥田 真琴, 末廣 雄登, 東條 文和, 又吉 紗綾, 仲 周平, 仲野 道代, 仲野 和彦

    小児歯科学雑誌   62 ( 大会抄録号 )   120 - 120   2024.4

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  • コラーゲン結合タンパクCnmとヒト免疫グロブリンの結合に関する分子生物学的検討

    末原 佳奈, 松岡 大貴, 仲 周平, 野村 良太, 仲野 和彦, 仲野 道代, 三崎 太郎, 長澤 康行, 伊藤 誓悟

    小児歯科学雑誌   62 ( 大会抄録号 )   149 - 149   2024.4

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  • ラットIgA腎症モデルにおける各種臓器での遺伝子発現の網羅的解析

    松岡 大貴, 末原 佳奈, 仲 周平, 野村 良太, 仲野 和彦, 仲野 道代

    小児歯科学雑誌   62 ( 大会抄録号 )   153 - 153   2024.4

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  • 非アルコール性脂肪肝炎患者口腔内から分離したStreptococcus mutansの各臓器における局在の検討

    中野 聡大, 田畑 佳子, 仲 周平, 仲野 道代

    小児歯科学雑誌   62 ( 地方会抄録号 )   63 - 63   2024.2

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  • 廃棄される貝殻から生成したハイドロキシアパタイトのStreptococcus mutansに対する抑制効果メカニズムの検討

    金木 亜美, 小川 将史, 臼田 桃子, 亀谷 茉莉子, 秋友 達哉, 末廣 雄登, 又吉 紗綾, 仲 周平, 大川 玲奈, 光畑 智恵子, 仲野 道代, 仲野 和彦, 野村 良太, 八木 正敏, 谷口 泰造, 溝口 敏郎, 藤川 幸樹

    小児歯科学雑誌   62 ( 地方会抄録号 )   60 - 61   2024.2

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  • Inhibitory Effects of Shikonin Dispersion, an Extract of Lithospermum erythrorhizon Encapsulated in β-1,3-1,6 Glucan, on Streptococcus mutans and Non-Mutans Streptococci. International journal

    Ryota Nomura, Yuto Suehiro, Fumikazu Tojo, Saaya Matayoshi, Rena Okawa, Masakazu Hamada, Shuhei Naka, Michiyo Matsumoto-Nakano, Rika Unesaki, Kazuya Koumoto, Keiko Kawauchi, Takahito Nishikata, Tatsuya Akitomo, Chieko Mitsuhata, Masatoshi Yagi, Toshiro Mizoguchi, Koki Fujikawa, Taizo Taniguchi, Kazuhiko Nakano

    International journal of molecular sciences   25 ( 2 )   2024.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    Shikonin is extracted from the roots of Lithospermum erythrorhizon, and shikonin extracts have been shown to have inhibitory effects on several bacteria. However, shikonin extracts are difficult to formulate because of their poor water solubility. In the present study, we prepared a shikonin dispersion, which was solubilized by the inclusion of β-1,3-1,6 glucan, and analysed the inhibitory effects of this dispersion on Streptococcus mutans and non-mutans streptococci. The shikonin dispersion showed pronounced anti-S. mutans activity, and inhibited growth of and biofilm formation by this bacterium. The shikonin dispersion also showed antimicrobial and antiproliferative effects against non-mutans streptococci. In addition, a clinical trial was conducted in which 20 subjects were asked to brush their teeth for 1 week using either shikonin dispersion-containing or non-containing toothpaste, respectively. The shikonin-containing toothpaste decreased the number of S. mutans in the oral cavity, while no such effect was observed after the use of the shikonin-free toothpaste. These results suggest that shikonin dispersion has an inhibitory effect on S. mutans and non-mutans streptococci, and toothpaste containing shikonin dispersion may be effective in preventing dental caries.

    DOI: 10.3390/ijms25021075

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  • Diagnosis of maxillary lateral incisor dens invaginatus and therapeutic approach

    Setsuyo Morimoto, Kana Goto, Asaumi Haruka, Tabata Keiko, Daiki Matsuoka, Shuhei Naka, Michiyo Matsumoto-Nakano

    Pediatric Dental Journal   33 ( 3 )   216 - 222   2023.12

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.pdj.2023.06.003

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  • 非アルコール性脂肪肝炎患者から分離したStreptococcus mutansの増殖能に鉄イオンが及ぼす影響について

    中野 聡大, 田畑 佳子, 仲 周平, 仲野 道代

    岡山歯学会雑誌   42 ( 2 )   78 - 78   2023.12

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  • Porphyromonas gingivalis infection in the oral cavity is associated with elevated galactose-deficient IgA1 and increased nephritis severity in IgA nephropathy.

    Seigo Ito, Taro Misaki, Yasuyuki Nagasawa, Ryota Nomura, Shuhei Naka, Akiko Fukunaga, Daiki Matsuoka, Saaya Matayoshi, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Clinical and experimental nephrology   2023.10

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    BACKGROUND: The relationship between the major periodontal bacteria, Porphyromonas gingivalis, and the pathogenesis of IgA nephropathy (IgAN)-particularly with respect to galactose-deficient IgA1 (Gd-IgA1)-has not been fully elucidated. METHODS: Saliva samples from 30 IgAN patients and 44 patients with chronic kidney disease (CKD) were subjected to analysis of P. gingivalis status via polymerase chain reaction using a set of P. gingivalis-specific primers. The associations between P. gingivalis presence and clinical parameters, including plasma Gd-IgA1, were analyzed in each group. RESULTS: Compared with the CKD group, the IgAN group demonstrated significantly higher plasma Gd-IgA1 levels (p < 0.05). Compared with the P. gingivalis-negative subgroup, the P. gingivalis-positive subgroup exhibited significantly higher plasma Gd-IgA1 levels in both IgAN and CKD patients (p < 0.05). Additionally, among IgAN patients, the P. gingivalis-positive subgroup displayed significantly higher plasma Gd-IgA1 and urine protein levels, compared with the P. gingivalis-negative subgroup (p < 0.05). With respect to renal biopsy findings, the frequencies of segmental glomerulosclerosis and tubular atrophy/interstitial fibrosis were significantly greater in the P. gingivalis-positive subgroup than in the P. gingivalis-negative subgroup, according to the Oxford classification of IgAN (p < 0.05). CONCLUSION: Our findings suggest an association between the presence of P. gingivalis in the oral cavity and the pathogenesis of IgAN, mediated by increased levels of Gd-IgA1.

    DOI: 10.1007/s10157-023-02411-4

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  • Inhibitory Effect of Adsorption of Streptococcus mutans onto Scallop-Derived Hydroxyapatite. International journal

    Momoko Usuda, Mariko Kametani, Masakazu Hamada, Yuto Suehiro, Saaya Matayoshi, Rena Okawa, Shuhei Naka, Michiyo Matsumoto-Nakano, Tatsuya Akitomo, Chieko Mitsuhata, Kazuya Koumoto, Keiko Kawauchi, Takahito Nishikata, Masatoshi Yagi, Toshiro Mizoguchi, Koki Fujikawa, Taizo Taniguchi, Kazuhiko Nakano, Ryota Nomura

    International journal of molecular sciences   24 ( 14 )   2023.7

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    Hydroxyapatite adsorbs various substances, but little is known about the effects on oral bacteria of adsorption onto hydroxyapatite derived from scallop shells. In the present study, we analyzed the effects of adsorption of Streptococcus mutans onto scallop-derived hydroxyapatite. When scallop-derived hydroxyapatite was mixed with S. mutans, a high proportion of the bacterial cells adsorbed onto the hydroxyapatite in a time-dependent manner. An RNA sequencing analysis of S. mutans adsorbed onto hydroxyapatite showed that the upregulation of genes resulted in abnormalities in pathways involved in glycogen and histidine metabolism and biosynthesis compared with cells in the absence of hydroxyapatite. S. mutans adsorbed onto hydroxyapatite was not killed, but the growth of the bacteria was inhibited. Electron microscopy showed morphological changes in S. mutans cells adsorbed onto hydroxyapatite. Our results suggest that hydroxyapatite derived from scallop shells showed a high adsorption ability for S. mutans. This hydroxyapatite also caused changes in gene expression related to the metabolic and biosynthetic processes, including the glycogen and histidine of S. mutans, which may result in a morphological change in the surface layer and the inhibition of the growth of the bacteria.

    DOI: 10.3390/ijms241411371

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  • Eruption cyst caused by congenital tooth in low birth weight infant

    Eri Yoshida, Kana Goto, Daiki Matsuoka, Yukiko Miyai, Haruka Asaumi, Keiko Tabata, Shuhei Naka, Michiyo Matsumoto-Nakano

    Pediatric Dental Journal   2023.7

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.pdj.2023.06.004

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  • 口腔内のcnm遺伝子陽性S.mutansとIgA腎症患者の糖鎖異常IgA沈着の関連性

    三崎 太郎, 仲 周平, 鈴木 仁, 李 明峰, 青木 良輔, 長澤 康行, 松岡 大貴, 伊藤 誓悟, 野村 良太, 仲野 道代, 鈴木 祐介, 仲野 和彦

    日本腎臓学会誌   65 ( 3 )   271 - 271   2023.5

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  • 口腔内のcnm遺伝子陽性S.mutansとIgA腎症患者の糖鎖異常IgA沈着の関連性

    三崎 太郎, 仲 周平, 鈴木 仁, 李 明峰, 青木 良輔, 長澤 康行, 松岡 大貴, 伊藤 誓悟, 野村 良太, 仲野 道代, 鈴木 祐介, 仲野 和彦

    日本腎臓学会誌   65 ( 3 )   271 - 271   2023.5

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  • 腎炎のあたらしい"モデル動物"の開発 ラットおよびマウスを用いた口腔細菌のIgA腎症発症への影響の検討

    野村 良太, 長澤 康行, 三崎 太郎, 仲 周平, 仲野 道代, 仲野 和彦

    日本腎臓学会誌   65 ( 3 )   210 - 210   2023.5

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  • Cnm陽性Streptococcus mutansの分子生物学的解析(Molecular biological analysis of Cnm positive Streptococcus mutans)

    Matsuoka Daiki, Naka Shuhei, Goto Kana, Nomura Ryota, Nakano Kazuhiko, Matsumoto-Nakano Michiyo

    小児歯科学雑誌   61 ( 大会抄録号 )   274 - 274   2023.4

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  • cnm-positive Streptococcus mutans is associated with galactose-deficient IgA in patients with IgA nephropathy. International journal

    Taro Misaki, Shuhei Naka, Hitoshi Suzuki, Mingfeng Lee, Ryosuke Aoki, Yasuyuki Nagasawa, Daiki Matsuoka, Seigo Ito, Ryota Nomura, Michiyo Matsumoto-Nakano, Yusuke Suzuki, Kazuhiko Nakano

    PloS one   18 ( 3 )   e0282367   2023

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    The presence of Streptococcus mutans expressing Cnm protein encoded by cnm (cnm-positive S. mutans) in the oral cavity is associated with immunoglobulin A (IgA) nephropathy (IgAN). However, the precise mechanism by which cnm-positive S. mutans is involved in the pathogenesis of IgAN remains unclear. The present study evaluated glomerular galactose-deficient IgA1 (Gd-IgA1) to clarify the association between the presence of cnm-positive S. mutans and glomerular Gd-IgA1 in patients with IgAN. The presence of S. mutans and cnm-positive S. mutans was evaluated by polymerase chain reaction in saliva specimens from 74 patients with IgAN or IgA vasculitis. Immunofluorescent staining of IgA and Gd-IgA1 using KM55 antibody in clinical glomerular tissues was then performed. There was no significant association between the glomerular staining intensity of IgA and the positive rate of S. mutans. However, there was a significant association between the glomerular staining intensity of IgA and the positive rate of cnm-positive S. mutans (P < 0.05). There was also a significant association between the glomerular staining intensity of Gd-IgA1 (KM55) and the positive rate of cnm-positive S. mutans (P < 0.05). The glomerular staining intensity of Gd-IgA1 (KM55) was not associated with the positive rate of S. mutans. These results suggest that cnm-positive S. mutans in the oral cavity is associated with the pathogenesis of Gd-IgA1 in patients with IgAN.

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  • Distribution of periodontopathic bacterial species between saliva and tonsils.

    Ryota Nomura, Yasuyuki Nagasawa, Taro Misaki, Seigo Ito, Shuhei Naka, Mieko Okunaka, Maiko Watanabe, Kenzo Tsuzuki, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Odontology   111 ( 3 )   719 - 727   2022.12

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    Periodontopathic bacteria cause an inflammatory disease localized in the periodontal tissue and are associated with various conditions in other body parts. The distribution of periodontopathic bacterial species in the tonsils is unknown, even though the tonsils are located close to the oral cavity, and inflammation of the tonsils causes various systemic diseases. We detected the major periodontopathic bacterial species residing in saliva and tonsil specimens from 25 subjects undergoing tonsillectomy. Nine of the ten major periodontopathic bacterial species were detected by polymerase chain reaction of tonsil specimens, among which Campylobacter rectus was the most common (80.0%), followed by Porphyromonas gingivalis (36.0%). The other seven types of periodontopathic bacterial species were distributed with 0% to 25.0% abundance in the tonsil specimens. C. rectus had a high detection rate in tonsil specimens (> 75.0%), regardless of whether it was detected in the corresponding saliva specimens. However, the detection rate for P. gingivalis in tonsil specimens was significantly higher in subjects with P. gingivalis-positive saliva (77.8%) than in those with P. gingivalis-negative saliva (6.3%; P < 0.001). Furthermore, 75.0% of P. gingivalis in tonsil specimens did not have the known fimA gene that encodes the 41-kDa filamentous appendage protein FimA, which is expressed on the cell surface of the bacteria. Our results suggest that certain periodontopathic bacterial species are detected in the tonsils either independently of or depending on their distribution in the oral cavity and may be involved in tonsil-related diseases.

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  • Cnm of Streptococcus mutans is important for cell surface structure and membrane permeability Reviewed

    Shuhei Naka, Daiki Matsuoka, Kana Goto, Taro Misaki, Yasuyuki Nagasawa, Seigo Ito, Ryota Nomura, Kazuhiko Nakano, Michiyo Matsumoto-Nakano

    Frontiers in Cellular and Infection Microbiology   12   2022.9

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    Streptococcus mutans, a Gram-positive facultative anaerobic bacterium, is a major pathogen of dental caries. The protein Cnm of S. mutans is involved in collagen binding, but its other biological functions are unknown. In this study, a Cnm-deficient isogenic mutant and a complementation strain were generated from a Cnm-positive S. mutans strain to help determine the properties of Cnm. Initially, comparison of the cell surface structure was performed by electron microscopy, which demonstrated that Cnm appears to be localized on the cell surface and associated with a protruding cell surface structure. Deep RNA sequencing of the strains revealed that the defect in Cnm caused upregulated expression of many genes related to ABC transporters and cell-surface proteins, while a few genes were downregulated. The amount of biofilm formed by the Cnm-defective strain increased compared with the parental and complemented strains, but the biofilm structure was thinner because of elevated expression of genes encoding glucan synthesis enzymes, leading to increased production of extracellular polysaccharides. Particular antibiotics, including bacitracin and chloramphenicol, had a lower minimum inhibitory concentration for the Cnm-defective strain than particular antibiotics, including bacitracin and chloramphenicol, compared with the parental and complemented strains. Our results suggest that S. mutans Cnm is located on the cell surface, gives rise to the observed protruding cell surface, and is associated with several biological properties related to membrane permeability.

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  • Simultaneous Presence of Campylobacter rectus and Cnm-Positive Streptococcus mutans in the Oral Cavity Is Associated with Renal Dysfunction in IgA Nephropathy Patients: 5-Year Follow-Up Analysis. International journal

    Taro Misaki, Shuhei Naka, Yasuyuki Nagasawa, Daiki Matsuoka, Seigo Ito, Ryota Nomura, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Nephron   147 ( 3-4 )   1 - 10   2022.8

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    BACKGROUND: The simultaneous presence of Streptococcus mutans expressing the Cnm protein encoded by cnm (i.e., cnm-positive S. mutans) and Campylobacter rectus in the oral cavity has been associated with proteinuria in patients with IgA nephropathy (IgAN). OBJECTIVES: The present study evaluated the relationship between renal function and oral bacteria in patients with IgAN over 5 years of follow-up. METHODS: The presence of C. rectus and cnm-positive S. mutans in saliva samples of 117 patients with IgAN was initially evaluated by polymerase chain reaction. Patients were then divided into four groups according to the results of C. rectus and cnm-positive S. mutans detection: group A: C. rectus (-), cnm-positive S. mutans (-); group B: C. rectus (+), cnm-positive S. mutans (-); group C: C. rectus (-), cnm-positive S. mutans (+); and group D: C. rectus (+), cnm-positive S. mutans (+). Clinical characteristics were prospectively followed for 5 years. RESULTS: Serum creatinine levels were significantly higher in group D than in group A over 5 years of follow-up. Additionally, the proportion of patients with an estimated glomerular filtration rate <45 mL/min increased over time; it was significantly greater in group D than in group A over 5 years of follow-up. CONCLUSION: These results suggest that the simultaneous presence of C. rectus and cnm-positive S. mutans in the oral cavity is associated with renal dysfunction in IgAN patients.

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  • Porphyromonas gingivalis経鼻投与によるIgA腎症モデルマウスの作製

    長澤 康行, 野村 良太, 三崎 太郎, 仲 周平, 伊藤 誓悟, 和唐 薫子, 楠 博, 山崎 博充, 新村 健, 仲野 道代, 仲野 和彦

    日本腎臓学会誌   64 ( 3 )   243 - 243   2022.5

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  • cnm遺伝子陽性S.mutansとC.rectusの口腔内の存在は5年後のIgA腎症患者の腎機能増悪に関連する

    三崎 太郎, 塩崎 友里子, 伊藤 大介, 清水 吉貴, 鈴木 由美子, 仲 周平, 野村 良太, 長澤 康行, 伊藤 誓悟, 仲野 道代, 仲野 和彦

    日本腎臓学会誌   64 ( 3 )   243 - 243   2022.5

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  • Title IgA Nephropathy and Oral Bacterial Species Related to Dental Caries and Periodontitis. Reviewed International journal

    Yasuyuki Nagasawa, Taro Misaki, Seigo Ito, Shuhei Naka, Kaoruko Wato, Ryota Nomura, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    International journal of molecular sciences   23 ( 2 )   2022.1

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    A relationship between IgA nephropathy (IgAN) and bacterial infection has been suspected. As IgAN is a chronic disease, bacteria that could cause chronic infection in oral areas might be pathogenetic bacteria candidates. Oral bacterial species related to dental caries and periodontitis should be candidates because these bacteria are well known to be pathogenic in chronic dental disease. Recently, several reports have indicated that collagen-binding protein (cnm)-(+) Streptococcs mutans is relate to the incidence of IgAN and the progression of IgAN. Among periodontal bacteria, Treponema denticola, Porphyromonas gingivalis and Campylobacte rectus were found to be related to the incidence of IgAN. These bacteria can cause IgAN-like histological findings in animal models. While the connection between oral bacterial infection, such as infection with S. mutans and periodontal bacteria, and the incidence of IgAN remains unclear, these bacterial infections might cause aberrantly glycosylated IgA1 in nasopharynx-associated lymphoid tissue, which has been reported to cause IgA deposition in mesangial areas in glomeruli, probably through the alteration of microRNAs related to the expression of glycosylation enzymes. The roles of other factors related to the incidence and progression of IgA, such as genes and cigarette smoking, can also be explained from the perspective of the relationship between these factors and oral bacteria. This review summarizes the relationship between IgAN and oral bacteria, such as cnm-(+) S. mutans and periodontal bacteria.

    DOI: 10.3390/ijms23020725

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  • Relationship between IgA Nephropathy and Porphyromonas gingivalis; Red Complex of Periodontopathic Bacterial Species. Reviewed International journal

    Yasuyuki Nagasawa, Ryota Nomura, Taro Misaki, Seigo Ito, Shuhei Naka, Kaoruko Wato, Mieko Okunaka, Maiko Watabe, Katsuya Fushimi, Kenzo Tsuzuki, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    International journal of molecular sciences   22 ( 23 )   2021.12

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    IgA nephropathy (IgAN) has been considered to have a relationship with infection in the tonsil, because IgAN patients often manifest macro hematuria just after tonsillitis. In terms of oral-area infection, the red complex of periodontal bacteria (Porphyromonas gingivalis (P. gingivalis), Treponema denticol (T. denticola) and Tannerella forsythia (T. forsythia)) is important, but the relationship between these bacteria and IgAN remains unknown. In this study, the prevalence of the red complex of periodontal bacteria in tonsil was compared between IgAN and tonsillitis patients. The pathogenicity of IgAN induced by P. gingivalis was confirmed by the mice model treated with this bacterium. The prevalence of P. gingivalis and T. forsythia in IgAN patients was significantly higher than that in tonsillitis patients (p < 0.001 and p < 0.05, respectively). A total of 92% of tonsillitis patients were free from red complex bacteria, while only 48% of IgAN patients had any of these bacteria. Nasal administration of P. gingivalis in mice caused mesangial proliferation (p < 0.05 at days 28a nd 42; p < 0.01 at days 14 and 56) and IgA deposition (p < 0.001 at day 42 and 56 after administration). Scanning-electron-microscopic observation revealed that a high-density Electron-Dense Deposit was widely distributed in the mesangial region in the mice kidneys treated with P. gingivalis. These findings suggest that P. gingivalis is involved in the pathogenesis of IgAN.

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  • 扁桃と口腔内の歯周病菌の一致率の検討

    長澤 康行, 野村 良太, 三崎 太郎, 仲 周平, 伊藤 誓悟, 和唐 薫子, 木田 有利, 名波 正義, 倉賀野 隆裕, 仲野 道代, 仲野 和彦

    日本腎臓学会誌   63 ( 4 )   494 - 494   2021.6

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  • Inhibitory effects of flavedo, albedo, fruits, and leaves of Citrus unshiu extracts on Streptococcus mutans. Reviewed International journal

    Ryota Nomura, Jumpei Ohata, Masatoshi Otsugu, Rena Okawa, Shuhei Naka, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Archives of oral biology   124   105056 - 105056   2021.4

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    OBJECTVES: Citrus unshiu has been shown to exhibit antimicrobial effects against citrus diseases. In the present study, C. unshiu was divided into flavedo, albedo, fruits, and leaves; the inhibitory effects of these extracts on Streptococcus mutans, a major pathogen of dental caries, were investigated. DESIGN: C. unshiu specimens were separated into flavedo, albedo, fruits, and leaves. First, pH values and polyphenol amounts in Citrus extracts were measured. In addition, Citrus extract was added to the bacterial suspensions of S. mutans MT8148, and inhibitory effects of C. unshiu extracts on MT8148 for antimicrobial activity, bacterial growth, and biofilm formation were analyzed. These assays were also performed using C. sinensis extracts. RESULTS: Among these extracts, albedo exhibited a pH value closest to neutral, while the fruits exhibited the most acidic pH value; the pH values significantly differed between these extracts (P < 0.05). In addition, the amounts of polyphenols were significantly higher in albedo than in other extracts (P < 0.001). All extracts showed inhibitory effects on MT8148 for antimicrobial activity, bacterial growth and biofilm formation. These inhibitory effects were significantly stronger in flavedo, albedo, and fruits, compared with leaves (P < 0.05). Furthermore, extracts of Citrus sinensis also showed inhibitory effects on S. mutans, although these effects were weaker than the effects of C. unshiu. CONCLUSION: These results suggest that extracts from C. unshiu fruits exhibit inhibitory effects on S. mutans, among which albedo may be especially useful for dental caries prevention due to its neutral pH and abundant polyphenols, in addition to its inhibitory effects.

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  • Streptococcus mutans induces IgA nephropathy-like glomerulonephritis in rats with severe dental caries. Reviewed International journal

    Shuhei Naka, Kaoruko Wato, Taro Misaki, Seigo Ito, Daiki Matsuoka, Yasuyuki Nagasawa, Ryota Nomura, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Scientific reports   11 ( 1 )   5784 - 5784   2021.3

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    The mechanisms underlying immunoglobulin A nephropathy (IgAN), the most common chronic form of primary glomerulonephritis, remain poorly understood. Streptococcus mutans, a Gram-positive facultatively anaerobic oral bacterium, is a common cause of dental caries. In previous studies, S. mutans isolates that express Cnm protein on their cell surface were frequently detected in IgAN patients. In the present study, inoculation of Cnm-positive S. mutans in the oral cavities of 2-week-old specific-pathogen free Sprague-Dawley rats fed a high-sucrose diet for 32 weeks produced severe dental caries in all rats. Immunohistochemical analyses of the kidneys using IgA- and complement C3-specific antibodies revealed positive staining in the mesangial region. Scanning electron microscopy revealed a wide distribution of electron dense deposits in the mesangial region and periodic acid-Schiff staining demonstrated prominent proliferation of mesangial cells and mesangial matrix. These results suggest that IgAN-like glomerulonephritis was induced in rats with severe dental caries by Cnm-positive S. mutans.

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  • Non-alcoholic steatohepatitis caused by oral bacteria Invited Reviewed

    Shuhei Naka, Michiyo Matsumoto-Nakano

    Pediatric Dental Journal   31   11 - 16   2021.2

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  • Intravenous administration of Streptococcus mutans induces IgA nephropathy-like lesions. Reviewed

    Shuhei Naka, Kaoruko Wato, Taro Misaki, Seigo Ito, Yasuyuki Nagasawa, Ryota Nomura, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Clinical and experimental nephrology   24 ( 12 )   1122 - 1131   2020.12

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    BACKGROUND: IgA nephropathy (IgAN) is one of the most frequently occurring types of chronic glomerulonephritis. Previous analyses have revealed that a major pathogen of dental caries, Streptococcus mutans [which expresses collagen-binding protein (Cnm) on its surface], is involved in the pathogenesis of IgAN. METHODS: Cnm-positive S. mutans isolated from a patient with IgAN was intravenously administered to specific pathogen-free Sprague-Dawley rats to evaluate their kidney conditions. RESULTS: The urinary protein level of the S. mutans group reached a plateau at 30 days, with increased numbers of mesangial cells and an increased mesangial matrix. The numbers of rats with IgA-positive and/or C3-positive glomeruli were significantly greater in the S. mutans group than in the control group at 45 days (P < 0.05). Electron microscopy analyses revealed electron-dense depositions in the mesangial area among rats in the S. mutans group. There were significantly more CD68-positive cells (macrophages) in the glomeruli of the S. mutans group than in the glomeruli of the control group during the late phase (P < 0.05), similar to the findings in patients with IgAN. CONCLUSION: Our results suggested that intravenous administration of Cnm-positive S. mutans caused transient induction of IgAN-like lesions in rats.

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  • Potential involvement of Streptococcus mutans possessing collagen binding protein Cnm in infective endocarditis. Reviewed International journal

    Ryota Nomura, Masatoshi Otsugu, Masakazu Hamada, Saaya Matayoshi, Noboru Teramoto, Naoki Iwashita, Shuhei Naka, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Scientific reports   10 ( 1 )   19118 - 19118   2020.11

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    Streptococcus mutans, a significant contributor to dental caries, is occasionally isolated from the blood of patients with infective endocarditis. We previously showed that S. mutans strains expressing collagen-binding protein (Cnm) are present in the oral cavity of approximately 10-20% of humans and that they can effectively invade human umbilical vein endothelial cells (HUVECs). Here, we investigated the potential molecular mechanisms of HUVEC invasion by Cnm-positive S. mutans. The ability of Cnm-positive S. mutans to invade HUVECs was significantly increased by the presence of serum, purified type IV collagen, and fibrinogen (p < 0.001). Microarray analyses of HUVECs infected by Cnm-positive or -negative S. mutans strains identified several transcripts that were differentially upregulated during invasion, including those encoding the small G protein regulatory proteins ARHGEF38 and ARHGAP9. Upregulation of these proteins occurred during invasion only in the presence of serum. Knockdown of ARHGEF38 strongly reduced HUVEC invasion by Cnm-positive S. mutans. In a rat model of infective endocarditis, cardiac endothelial cell damage was more prominent following infection with a Cnm-positive strain compared with a Cnm-negative strain. These results suggest that the type IV collagen-Cnm-ARHGEF38 pathway may play a crucial role in the pathogenesis of infective endocarditis.

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  • Identification and functional analysis of glutamine transporter in Streptococcus mutans. Reviewed International journal

    Yuko Morikawa, Setsuyo Morimoto, Eri Yoshida, Shuhei Naka, Hiroaki Inaba, Michiyo Matsumoto-Nakano

    Journal of oral microbiology   12 ( 1 )   1797320 - 1797320   2020.8

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    Background: Streptococcus mutans, a biofilm-forming bacterium, possesses several transporters that function as import/export molecules. Among them, the PII protein family is composed of members that regulate glutamine synthesis in bacterial species. Objective: In this study, we characterized the function of the glutamine transporter in S. mutans MT8148. Methods: The SMU.732 gene, corresponding to glnP in S. mutans, is homologous to the glutamine transporter gene in Bacillus subtilis. We constructed a glnP-inactivated mutant strain (GEMR) and a complement strain (comp-GEMR) and evaluated their biological functions. Results: Growth of GEMR was similar in the presence and absence of glutamine, whereas the growth rates of MT8148 and comp-GEMR were significantly lower in the presence of glutamine as compared to its absence. Furthermore, biofilms formed by MT8148 and comp-GEMR were significantly thicker than that formed by GEMR, while the GEMR strain showed a significantly lower survival rate in an acidic environment than the other strains. Addition of n-phenyl-2-naphthylamine, used to label of the membrane, led to increased fluorescence intensity of MT8148 and GEMR, albeit that was significantly lower in the latter. Conclusions: These results suggest that glnP is associated with glutamine transport in S. mutans, especially the import of glutamine involved in biofilm formation.

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  • Specific strains of Streptococcus mutans, a pathogen of dental caries, in the tonsils, are associated with IgA nephropathy. Reviewed International journal

    Seigo Ito, Taro Misaki, Shuhei Naka, Kaoruko Wato, Yasuyuki Nagasawa, Ryota Nomura, Masatoshi Otsugu, Michiyo Matsumoto-Nakano, Kazuhiko Nakano, Hiroo Kumagai, Naoki Oshima

    Scientific reports   9 ( 1 )   20130 - 20130   2019.12

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    Streptococcus mutans is known to be a major causative agent of dental caries, and strains expressing the cell surface collagen-binding Cnm protein contribute to the development of several systemic diseases. A relationship between tonsillar immunity and glomerulonephritis has been recognized in IgA nephropathy (IgAN), and specific pathogens may have effects on tonsillar immunity (mucosal immunity). Here, we present findings showing a relationship between the presence of Cnm-positive S. mutans strains in the tonsils of IgAN patients and IgAN condition/pathogenesis. Analyses of tonsillar specimens obtained from patients with IgAN (n = 61) and chronic tonsillitis (controls; n = 40) showed that the Cnm protein-positive rate was significantly higher in IgAN patients. Among IgAN patients, the tonsillar Cnm-positive group (n = 15) had a significantly higher proportion of patients with high urinary protein (>1.5 g/gCr) and lower serum albumin level than the Cnm-negative group (n = 46). Additionally, Cnm protein and CD68, a common human macrophage marker, were shown to be merged in the tonsils of IgAN patients. These findings suggest that Cnm-positive S. mutans strains in the tonsils may be associated with severe IgAN.

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  • Case of autoimmune neutropenia with severe marginal periodontitis Reviewed

    Setsuyo Morimoto, Keiko Hirano, Keiko Tabata, Haruka Asaumi, Yuko Morikawa, Yuki Matsumi, Shuhei Naka, Michiyo Matsumoto-Nakano

    PEDIATRIC DENTAL JOURNAL   29 ( 3 )   138 - 145   2019.12

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    Early onset periodontitis is rarely seen in infants, though often leads to an acute and serious clinical course when encountered in such patients. Autoimmune neutropenia presents systemic and dental symptoms, as depressed resistance to bacterial infection is caused by a disorder that reduces the number of neutrophils. This disease can result in not only gingival inflammation but also destruction of periodontal tissues, such as attachment loss, alveolar bone absorption, and early tooth loss in primary as well as mixed dentition. Here, we report treatment of a child with marginal periodontitis from the age of 3 years-7 years 9 months. No systemic manifestations were noted until 3 years of age, thus the patient had never received a detailed examination or medication related to the disease. Following examinations at our department, we referred the patient to a pediatrician at our university hospital for possible systemic disease, who made a diagnosis of autoimmune neutropenia. Although administration of antibiotics and professional dental care were continued, neutrophil count was not increased and progressive periodontal destruction was observed. Extraction of teeth with poor prognosis was performed and a prosthetic strategy for the missing teeth developed. It is important to recognize that periodontitis along with autoimmune neutropenia can appear in infants, even though the incidence is quite low. Early detection and early treatment of this disease is necessary for delaying progression of periodontitis and optimal occlusal induction of permanent teeth. (C) 2019 Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.pdj.2019.06.002

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  • Birooted primary canines identified in 8-year-old Japanese girl – Case report Reviewed

    Kazuma Kokomoto, Rena Okawa, Shuhei Naka, Ryota Nomura, Kazuhiko Nakano

    Pediatric Dental Journal   29 ( 1 )   48 - 51   2019.4

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  • Relationship between Streptococcus mutans expressing Cnm in the oral cavity and non-alcoholic steatohepatitis: a pilot study. Reviewed International journal

    Shuichi Tonomura, Shuhei Naka, Keiko Tabata, Tasuku Hara, Kojiro Mori, Saiyu Tanaka, Yoshio Sumida, Kazuyuki Kanemasa, Ryota Nomura, Michiyo Matsumoto-Nakano, Masafumi Ihara, Nobuyuki Takahashi, Kazuhiko Nakano

    BMJ open gastroenterology   6 ( 1 )   e000329   2019

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    Background: Non-alcoholic steatohepatitis (NASH) is a severe state of non-alcoholic fatty liver disease (NAFLD), which is pathologically characterised by steatosis, hepatocyte ballooning, and lobular inflammation. Host-microbial interaction has gained attention as one of the risk factors for NASH. Recently, cnm-gene positive Streptococcus mutans expressing cell surface collagen-binding protein, Cnm (cnm-positive S. mutans), was shown to aggravate NASH in model mice. Here, we assessed the detection rate of cnm-positive S. mutans in oral samples from patients with NASH among NAFLD. Methods: This single hospital cohort study included 41 patients with NAFLD. NASH was diagnosed histologically or by clinical score. The prevalence of cnm-positive S. mutans, oral hygiene and blood tests, including liver enzymes, adipocytokines and inflammatory and fibrosis markers, were assessed in biopsy-proven or clinically suspected NASH among NAFLD. Results: Prevalence of cnm-positive S. mutans was significantly higher in patients with NASH than patients without NASH (OR 3.8; 95% CI 1.02 to 15.5). The cnm-positive S. mutans was related to decreased numbers of naturally remaining teeth and increased type IV collagen 7S level (median (IQR) 10.0 (5.0-17.5) vs 20.0 (5.0-25.0), p=0.06; 5.1 (4.0-7.9) vs 4.4 (3.7-5.3), p=0.13, respectively). Conclusions: Prevalence of cnm-positive S. mutans in the oral cavity could be related to fibrosis of NASH among NAFLD.

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  • Dental management of unilateral multiple impacted primary teeth

    Yuki Matsumi, Yuko Morikawa, Eri Yoshida, Setsuyo Morimoto, Sho Yoshida, Tatsushi Matsumura, Seiji Iida, Yukiko Takashima, Shuhei Naka, Michiyo Matsumoto-Nakano

    PEDIATRIC DENTAL JOURNAL   28 ( 3 )   119 - 124   2018.12

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    Impacted primary teeth can be caused by odontogenic tumors such as odontomas, cystic diseases such as dentigerous and eruption cysts, and fibrous hyperplasia of the gingiva, while elimination of those causes reportedly results in normal eruption of primary teeth. We describe the course of a child from the age of 1 year until 4 years 10 months who had primary tooth eruption failure and was treated with dental methods. Although primary teeth expected to spontaneously erupt were followed, there were several on the left side that remained unerupted. We performed a left maxillary and mandibular gingivectomy to closely examine the cause of eruption delay and tooth germ dislocation, as well as attempt to induce eruption of the primary teeth. Based on histopathological results, the diagnosis was fibroma. Surgical procedures did not result in clear improvement of eruption failure. In order to improve masticatory function and aesthetics, the child was fixed with an artificial denture for all primary teeth not expected to erupt. (C) 2018 Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.pdj.2018.09.002

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  • A Potential New Risk Factor for Stroke: Streptococcus Mutans With Collagen-Binding Protein. Reviewed International journal

    Chikanori Inenaga, Kazuya Hokamura, Kazuhiko Nakano, Ryota Nomura, Shuhei Naka, Toshihiko Ohashi, Takashi Ooshima, Nagato Kuriyama, Toshimitsu Hamasaki, Koichiro Wada, Kazuo Umemura, Tokutaro Tanaka

    World neurosurgery   113   e77-e81   2018.5

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    BACKGROUND: Among human oral bacteria, particular kinds of Streptococcus mutans (SM) known as dental caries pathogens contain a collagen-binding protein, Cnm, and show platelet aggregation inhibition and matrix metalloproteinase-9 activation. We have previously reported that these strains may be a risk factor for intracerebral hemorrhage. As a major sample-providing hospital, we report the clinical details, including intracranial aneurysms and ischemic stroke. METHODS: After the study received approval from the Ethical Committee, 429 samples of whole saliva were obtained from patients who were admitted to or visited our hospital between February 16, 2010, and February 28, 2011. The study cohort comprised 48 patients with cardioembolic stroke (CES), 151 with non-CES infarct, 54 with intracerebral hemorrhage (ICH), 43 with ruptured intracranial aneurysm (RIA), and 97 with unruptured intracranial aneurysm (UIA). Cultured SM was identified as Cnm-positive when the corresponding gene was positive. The results were compared with those from 79 healthy volunteers. Relationships between Cnm-positive SM and known risk factors, including hypertension, diabetes, hyperlipidemia, smoking, and alcohol consumption, were analyzed. RESULTS: A statistically significant high Cnm-positive rate was observed in patients with CES, non-CES infarct, ICH, and RIA (P = 0.002, 0.039, 0.013, and 0.009, respectively). There were no relationships between Cnm-positive SM and known risk factors. CONCLUSIONS: Specific types of oral SM can be a risk factor for cardioembolic infarct, intracerebral hemorrhage, and intracranial aneurysm rupture. Further study is needed.

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  • Displacement of maxillary right second premolar caused by gutta percha filling in corresponding primary molar Reviewed

    Shuhei Naka, Kazuma Kokomoto, Jumpei Ohata, Rena Okawa, Ryota Nomura, Kazuhiko Nakano

    Pediatric Dental Journal   28 ( 1 )   13 - 18   2018.4

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    DOI: 10.1016/j.pdj.2017.10.002

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  • Odontoma associated with unerupted primary tooth in primary dentition - Three cases

    Yukiko Takashima, Yuko Morikawa, Atsushi Takagi, Yuki Matsumi, Tatsushi Matsumura, Seiji Iida, Shuhei Naka, Michiyo Matsumoto-Nakano

    PEDIATRIC DENTAL JOURNAL   28 ( 1 )   19 - 24   2018.4

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    Odontomas are generally encountered in permanent dentition and rarely seen in primary dentition. These lesions are regarded as essentially benign, though they often cause disturbances in eruption of the associated tooth. We present clinical findings and management of 3 cases of odontomas that occurred in primary dentition, including a 3-year-old girl referred for examination of an unerupted left upper primary canine, a 6-year-old boy with an unerupted left lower second primary molar, and a 5-year-old girl who was presented with an unerupted right upper second primary molar. In all cases, periapical and panoramic radiography revealed a radio-opaque mass surrounded by a narrow radiolucent space located above the crown of the unerupted tooth. Each was diagnosed as a compound odontoma interfering with eruption of a primary tooth and surgical removal was performed under general anesthesia for all patients, with the final diagnosis based on histological findings. Following surgery, the primary canine in Case 1 spontaneously erupted, while a space maintenance appliance was applied in Case 2 and 3. It is important to recognize that an odontoma can appear in primary dentition, though the incidence is quite low. Early detection and removal of an odontoma associated with an impacted primary tooth is necessary for optimal dentition. (C) 2017 Published by Elsevier Ltd on behalf of Japanese Society of Pediatric Dentistry.

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  • Campylobacter rectus in the Oral Cavity Correlates with Proteinuria in Immunoglobulin A Nephropathy Patients. Reviewed International journal

    Taro Misaki, Shuhei Naka, Kaoruko Wato, Rina Hatakeyama, Yasuyuki Nagasawa, Seigo Ito, Hiroaki Inaba, Ryota Nomura, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Nephron   139 ( 2 )   143 - 149   2018

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    BACKGROUND: Periodontitis-related pathogens, such as Campylobacter or Treponema species, have recently been shown to be associated with immunoglobulin A nephropathy (IgAN). Some strains of Streptococcus mutans, a major pathogen of dental caries, harbour the cnm gene that encodes a collagen-binding protein (Cnm). This has also been demonstrated to be associated with urinary protein levels in IgAN patients. OBJECTIVES: The purpose of the present study was to analyse the association of IgAN with C. rectus, Treponema denticola and cnm-positive S. mutans in the oral cavity of humans. METHODS: The presence of C. rectus, T. denticola and cnm-positive S. mutans strains in saliva samples of 117 IgAN patients and 56 healthy controls was evaluated by PCR, and the subjects' clinical parameters were analysed. RESULTS: C. rectus was significantly more prevalent in the IgAN group than in the control group (p < 0.05). The C. rectus-positive group was significantly associated with proteinuria in the IgAN group (p < 0.05). In addition, the C. rectus-positive and cnm-positive S. mutans group was shown to be more closely associated with urinary protein levels than the other groups (p < 0.0083). CONCLUSION: Our results suggest that harbouring C. rectus in the oral cavity could be associated with proteinuria in IgAN patients.

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  • Longitudinal comparison of Streptococcus mutans-induced aggravation of non-alcoholic steatohepatitis in mice. Reviewed International journal

    Shuhei Naka, Kaoruko Wato, Rina Hatakeyama, Rena Okawa, Ryota Nomura, Kazuhiko Nakano

    Journal of oral microbiology   10 ( 1 )   1428005 - 1428005   2018

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    Background: We previously reported that intravenous administration of Streptococcus mutans strain TW871 caused typical non-alcoholic steatohepatitis (NASH)-like findings in a high-fat diet (HFD) mouse model at 16 weeks after initiating the experiment. Objective: The purpose of the present study was to analyse mice administered S. mutans TW871 fed a HFD for various periods of time. Methods: First, 6-week-old C57BL/6J mice were fed an HFD for 4 weeks, then TW871 (1 × 107 CFU) or phosphate-buffered saline (PBS) were intravenously administered. Mice were euthanized 12, 16, 20, and 48 weeks after starting the experiment, and conventional clinical and histopathological evaluations were performed. Results: Typical NASH-like findings were not identified in the mice at 12 weeks, while they were observed in the TW871 group at 16 weeks, and the severity of NASH symptoms were increased at 20 weeks. Furthermore, signs of severe NASH were also observed at 48 weeks. In contrast, in the PBS-administered group, the NASH findings were identified only at 48 weeks and no typical NASH features were observed at 12, 16, or 20 weeks. Conclusion: These results suggest that intravenous administration of a specific S. mutans strain aggravates NASH in a time-dependent manner in the mice in contrast to mice without S. mutans exposure.

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  • The in vivo Inhibition of Oral Biofilm Accumulation and Streptococcus mutans by Ceramic Water. Reviewed International journal

    Ryota Nomura, Risa Yoneyama, Shuhei Naka, Masatoshi Otsugu, Yuko Ogaya, Rina Hatakeyama, Yumiko Morita, Jumpei Maruo, Michiyo Matsumoto-Nakano, Osamu Yamada, Kazuhiko Nakano

    Caries research   51 ( 1 )   58 - 67   2017

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    Combustion-synthesized titanium carbide ceramics uniformly disperse silver, producing silver ions and hydroxyl radicals in water. This generates antimicrobial activity against various bacteria. One such bacterium is Streptococcus mutans, a gram-positive anaerobic bacterium known as a major pathogen of dental caries. In this study, we analyzed the inhibition of oral biofilms and S. mutans by ceramic water in in vitro and human studies. S. mutans strains showed significantly lower antimicrobial and sucrose-dependent adhesion activity in the presence of ceramic powder compared with untreated culture medium. Confocal microscopy revealed that S. mutans biofilm structures with ceramic powder were thin and coarse. Twenty-seven volunteers (13 males, 14 females; 18-37 years old, mean 25.2 years) were enrolled for subsequent studies. After each meal, one group was asked to rinse with ceramic water while the other rinsed with untreated water for 1 week. After 1 week, the rinsing contents were switched between the groups and the same protocol was followed for an additional week. After rinsing with ceramic water, the average plaque score was 43.0 ± 3.7, which was significantly lower than the baseline value (74.1 ± 5.7, p < 0.001). However, no significant difference was observed when rinsing with untreated water. In addition, the total number of S. mutans in saliva was significantly reduced after rinsing with ceramic water compared with untreated water (p < 0.05). These results suggest that ceramic water possesses antimicrobial activity against S. mutans and inhibits biofilm formation. Rinsing with ceramic water can also inhibit dental plaque formation and S. mutans colonization in humans.

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  • Oral Cnm-positive Streptococcus Mutans Expressing Collagen Binding Activity is a Risk Factor for Cerebral Microbleeds and Cognitive Impairment. Reviewed International journal

    Isao Watanabe, Nagato Kuriyama, Fumitaro Miyatani, Ryota Nomura, Shuhei Naka, Kazuhiko Nakano, Masafumi Ihara, Komei Iwai, Daisuke Matsui, Etsuko Ozaki, Teruhide Koyama, Masaru Nishigaki, Toshiro Yamamoto, Aiko Tamura, Toshiki Mizuno, Kentaro Akazawa, Akihiro Takada, Kazuo Takeda, Kei Yamada, Masanori Nakagawa, Tokutaro Tanaka, Narisato Kanamura, Robert P Friedland, Yoshiyuki Watanabe

    Scientific reports   6   38561 - 38561   2016.12

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    Cerebral microbleeds (CMBs) are an important risk factor for stroke and dementia. We have shown that the collagen binding surface Cnm protein expressed on cnm-positive Streptococcus mutans is involved in the development of CMBs. However, whether the collagen binding activity of cnm-positive S. mutans is related to the nature of the CMBs or to cognitive impairment is unclear. Two-hundred seventy nine community residents (70.0 years) were examined for the presence or absence of cnm-positive S. mutans in the saliva by PCR and collagen binding activity, CMBs, and cognitive function were evaluated. Cnm-positive S. mutans was detected more often among subjects with CMBs (p < 0.01) than those without. The risk of CMBs was significantly higher (odds ratio = 14.3) in the group with S. mutans expressing collagen binding activity, as compared to the group without that finding. Deep CMBs were more frequent (67%) and cognitive function was lower among subjects with cnm-positive S. mutans expressing collagen binding activity. This work supports the role of oral health in stroke and dementia and proposes a molecular mechanism for the interaction.

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  • Contributions of Streptococcus mutans Cnm and PA antigens to aggravation of non-alcoholic steatohepatitis in mice. Reviewed International journal

    Shuhei Naka, Rina Hatakeyama, Yukiko Takashima, Michiyo Matsumoto-Nakano, Ryota Nomura, Kazuhiko Nakano

    Scientific reports   6   36886 - 36886   2016.11

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    Streptococcus mutans, a major pathogen of dental caries, can cause infective endocarditis after invading the bloodstream. Recently, intravenous administration of specific S. mutans strains was shown to aggravate non-alcoholic steatohepatitis (NASH) in a mouse model fed a high-fat diet. Here, we investigated the mechanism of this aggravation in a NASH mouse model by focusing on the S. mutans cell surface collagen-binding protein (Cnm) and the 190-kDa protein antigen (PA). Mice that were intravenously administered a S. mutans strain with a defect in Cnm (TW871CND) or PA (TW871PD) did not show clinical or histopathological signs of NASH aggravation, in contrast to those administered the parent strain TW871. The immunochemical analyses demonstrated higher levels of interferon-γ and metallothionein expression in the TW871 group than in the TW871CND and TW871PD groups. Analysis of bacterial affinity to cultured hepatic cells in the presence of unsaturated fatty acids revealed that the incorporation rate of TW871 was significantly higher than those of TW871CND and TW871PD. Together, our results suggest that Cnm and PA are important cell surface proteins for the NASH aggravation caused by S. mutans adhesion and affinity for hepatic cells.

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  • Presence of Streptococcus mutans strains harbouring the cnm gene correlates with dental caries status and IgA nephropathy conditions. International journal

    Taro Misaki, Shuhei Naka, Rina Hatakeyama, Akiko Fukunaga, Ryota Nomura, Taisuke Isozaki, Kazuhiko Nakano

    Scientific reports   6   36455 - 36455   2016.11

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    Streptococcus mutans is a major pathogen of human dental caries. Strains harbouring the cnm gene, which encodes Cnm, a collagen-binding protein, contribute to the development of several systemic diseases. In this study, we analysed S. mutans strains isolated from the oral cavity of immunoglobulin (Ig)A nephropathy (IgAN) patients to determine potential relationships between cnm and caries status as well as IgAN conditions. Saliva specimens were collected from 109 IgAN patients and the cnm status of isolated S. mutans strains was determined using PCR. In addition, the dental caries status (decayed, missing or filled teeth [DMFT] index) in patients who agreed to dental consultation (n = 49) was evaluated. The DMFT index and urinary protein levels in the cnm-positive group were significantly higher than those in the cnm-negative group (p < 0.05). Moreover, the urinary protein levels in the high DMFT (≥15) group were significantly higher than those in the low DMFT (<15) group (p < 0.05). Our results show that isolation of cnm-positive S. mutans strains from the oral cavity may be associated with urinary protein levels in IgAN patients, especially those with a high dental caries status.

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  • Lowe syndrome oral findings: Case report Reviewed

    Rena Okawa, Shuhei Naka, Kanae Saga, Kazuhiko Nakano

    Pediatric Dental Journal   26 ( 1 )   34 - 37   2016.4

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    DOI: 10.1016/j.pdj.2015.10.001

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  • Distribution of Streptococcus mutans strains with collagen-binding proteins in the oral cavity of IgA nephropathy patients.

    Taro Misaki, Shuhei Naka, Keiko Kuroda, Ryota Nomura, Tempei Shiooka, Yoshitaka Naito, Yumiko Suzuki, Hideo Yasuda, Taisuke Isozaki, Kazuhiko Nakano

    Clinical and experimental nephrology   19 ( 5 )   844 - 50   2015.10

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    BACKGROUND: IgA nephropathy (IgAN) is the most common primary chronic glomerulonephritis; however, its precise initiating pathogenesis remains unclear. Streptococcus mutans is a major pathogen of human dental caries. S. mutans strains with the cnm gene encoding Cnm, a collagen-binding protein, have been reported to contribute to the development of systemic diseases. However, the contribution of S. mutans with Cnm in the development of IgAN has not been reported. The aim of this study was to investigate the prevalence of cnm-positive S. mutans in IgAN patients and clarify the effects of cnm-positive S. mutans on the histological pathology of IgAN. METHODS: We identified the cnm gene in S. mutans isolated in saliva specimens, which were collected from IgAN patients (n = 53) and control subjects (n = 50). We evaluated the collagen-binding properties of S. mutans in IgAN patients and controls. The clinical parameters and histological scores were also assessed in IgAN patients. RESULTS: The rates of S. mutans isolation in IgAN and control groups were 84.0 and 84.9 %, respectively, not significantly dfferent. cnm-positive strains were significantly more prevalent in the IgAN group than in controls (32.1 vs. 14.0 %, p < 0.05). With regard to collagen-binding assays, the binding rates of cnm-positive strains were significantly higher in the IgAN group than in controls (96.6 vs. 30.0, p < 0.05). In addition, the segmental glomerulosclerosis scores were significantly higher in cnm-positive patients with IgAN than in cnm-negative patients with IgAN (0.94 vs. 0.57, p < 0.05). CONCLUSION: cnm-positive S. mutans strains are potentially associated with the pathogenesis of IgAN.

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  • Epulis appeared after exfoliation of natal tooth in infant Japanese boy Reviewed

    Rena Okawa, Kazuyo Fujita, Shuhei Naka, Ryota Nomura, Kazuhiko Nakano

    Pediatric Dental Journal   24 ( 3 )   189 - 191   2014.12

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  • Contribution of the interaction of Streptococcus mutans serotype k strains with fibrinogen to the pathogenicity of infective endocarditis. Reviewed International journal

    Ryota Nomura, Masatoshi Otsugu, Shuhei Naka, Noboru Teramoto, Ayuchi Kojima, Yoshinori Muranaka, Michiyo Matsumoto-Nakano, Takashi Ooshima, Kazuhiko Nakano

    Infection and immunity   82 ( 12 )   5223 - 34   2014.12

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    Streptococcus mutans, a pathogen responsible for dental caries, is occasionally isolated from the blood of patients with bacteremia and infective endocarditis (IE). Our previous study demonstrated that serotype k-specific bacterial DNA is frequently detected in S. mutans-positive heart valve specimens extirpated from IE patients. However, the reason for this frequent detection remains unknown. In the present study, we analyzed the virulence of IE from S. mutans strains, focusing on the characterization of serotype k strains, most of which are positive for the 120-kDa cell surface collagen-binding protein Cbm and negative for the 190-kDa protein antigen (PA) known as SpaP, P1, antigen I/II, and other designations. Fibrinogen-binding assays were performed with 85 clinical strains classified by Cbm and PA expression levels. The Cbm(+)/PA(-) group strains had significantly higher fibrinogen-binding rates than the other groups. Analysis of platelet aggregation revealed that SA31, a Cbm(+)/PA(-) strain, induced an increased level of aggregation in the presence of fibrinogen, while negligible aggregation was induced by the Cbm-defective isogenic mutant SA31CBD. A rat IE model with an artificial impairment of the aortic valve created using a catheter showed that extirpated heart valves in the SA31 group displayed a prominent vegetation mass not seen in those in the SA31CBD group. These findings could explain why Cbm(+)/PA(-) strains are highly virulent and are related to the development of IE, and the findings could also explain the frequent detection of serotype k DNA in S. mutans-positive heart valve clinical specimens.

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  • A specific Streptococcus mutans strain aggravates non-alcoholic fatty liver disease. Reviewed International journal

    S Naka, R Nomura, Y Takashima, R Okawa, T Ooshima, K Nakano

    Oral diseases   20 ( 7 )   700 - 6   2014.10

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    OBJECTIVE: Streptococcus mutans, a major dental caries pathogen, has shown to be associated with the aggravation of cerebral hemorrhage and inflammatory bowel diseases. In this study, we evaluated the effects ofS. mutans on the development of non-alcoholic steatohepatitis (NASH) in a mouse model. MATERIALS AND METHODS: Streptococcus mutans oral strain MT8148 (serotype c) and a blood isolate TW871 (k) were used. C57BL/6J mice (6 weeks old)were fed a high-fat diet for 4 weeks; the test strains or phosphate-buffered saline was then intravenously administered. Mice were euthanized after 8 or 12 weeks. Whole body, extirpated liver, and visceral fat weights were determined, and histopathological evaluations of the liver specimens were performed. RESULTS: Mice infected with TW871 showed significantly greater body and liver weights than those administered MT8148 or phosphate-buffered saline. Histopathological analyses revealed prominent infiltration of inflammatory cells and adipocellular deposition in livers extirpated 8 weeks after an infection with TW871; fibrosis was also observed in livers extirpated after 12 weeks. CONCLUSION: These results suggest that a specific strain of S. mutans could induce NASH.

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  • Delayed eruption of mandibular primary central incisors in a child with severe lingual inclination and their spontaneous movement to appropriate positions Reviewed

    Rena Okawa, Shuhei Naka, Miharu Higashino, Ryota Nomura, Kazuhiko Nakano

    Pediatric Dental Journal   24 ( 2 )   120 - 123   2014.8

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  • Hypoplasia in crown of primary mandibular left lateral incisor identified in infant Japanese girl Reviewed

    Rena Okawa, Shuhei Naka, Kanae Saga, Ryota Nomura, Kazuhiko Nakano

    Pediatric Dental Journal   24 ( 2 )   129 - 131   2014.8

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  • Aggravation of inflammatory bowel diseases by oral streptococci. Reviewed International journal

    A Kojima, R Nomura, S Naka, R Okawa, T Ooshima, K Nakano

    Oral diseases   20 ( 4 )   359 - 66   2014.5

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    OBJECTIVES: Streptococcus mutans can aggravate colitis in mice. We evaluated the virulence of colitis using type strains as well as blood isolates of several oral streptococcal species. MATERIALS AND METHODS: We investigated the susceptibility of blood isolates of several oral streptococci to phagocytosis, adhesion to and invasion of hepatic cells and interferon-γ secretion. A mouse model of dextran sodium sulphate-induced colitis was used to evaluate bacterial aggravation of colitis. In addition, interferon-γ antibody was administered to mice with prominent aggravation of colitis. RESULTS: In vitro analyses showed that Streptococcus sanguinis ATCC 10556 was a possible virulent strain among type strains of several oral streptococci, and that analysis of blood isolates of S. sanguinis TW289 revealed a potential virulent strain. Intravenous administration of ATCC 10556 and TW289 caused prominent aggravation of dextran sodium sulphate-induced colitis, and histopathological examinations showed that interferon-γ secretion due to infection of hepatic cells caused colitis aggravation. Administration of interferon-γ antibody suppressed TW289-induced colitis. CONCLUSION: These results suggest that some virulent oral streptococcal strains are associated with the aggravation of colitis induced by enhanced secretion of interferon-γ when they invade the bloodstream.

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  • Potential high virulence for infective endocarditis in Streptococcus mutans strains with collagen-binding proteins but lacking PA expression. Reviewed International journal

    R Nomura, S Naka, H Nemoto, M Otsugu, S Nakamura, T Ooshima, K Nakano

    Archives of oral biology   58 ( 11 )   1627 - 34   2013.11

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    OBJECTIVE: Streptococcus mutans, an aetiologic agent of dental caries, is a pathogen for infective endocarditis (IE). We investigated strains that express collagen-binding proteins (CBPs) with further classification based on expression of the 190-kDa protein antigen (PA). METHOD: Zeta-potential values of strains TW871 (CBP+/PA+) and MT8148 (CBP-/PA+), and their respective PA-defective mutant strains TW871PD (CBP+/PA-) and MT8148PD (CBP-/PA-), were analysed, as were their adhesion to and invasion of human umbilical vein endothelial cells (HUVECs). The distribution of strains from the oral cavities of 200 healthy individuals was analysed for CBP and/or PA expression and the strains were characterised for their adhesion and invasion properties. RESULTS: TW871PD and MT8148PD showed significantly lower zeta-potential values than TW871 and MT8148, respectively. Collagen-binding rates were significantly higher for TW871PD than for TW871 but nearly negligible for MT8148 and MT8148PD. The adhesion and invasion rates of HUVECs were significantly higher for TW871PD than for TW871 and significantly higher for TW871 than for MT8148 and MT8148PD. The prevalence of CBP+ strains was ~10% and ~3% in the case of CBP+/PA- strains. Analyses of 200 clinical strains showed the CBP+/PA- group to have higher adhesion and invasion rates than other groups. CONCLUSIONS: CBP+/PA- S. mutans strains, despite their low distribution frequency, may be highly virulent for infective endocarditis.

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  • Multilocus sequence typing of Streptococcus mutans strains with the cbm gene encoding a novel collagen-binding protein. Reviewed International journal

    Jinthana Lapirattanakul, Ryota Nomura, Hirotoshi Nemoto, Shuhei Naka, Takashi Ooshima, Kazuhiko Nakano

    Archives of oral biology   58 ( 8 )   989 - 96   2013.8

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    OBJECTIVE: Streptococcus mutans, an oral pathogen associated with infective endocarditis (IE), possesses two genes encoding collagen-binding proteins, namely cnm and cbm. In this study, we used multilocus sequence typing (MLST) of S. mutans with the cbm gene. DESIGN: Forty-five S. mutans strains including 15 strains with the cnm gene, 15 strains with the cbm gene, and 15 strains without these two genes were analysed by MLST. In addition, the collagen-binding properties as well as the abilities to adhere to and invade human umbilical vein endothelial cells (HUVEC) were also evaluated for all strains. RESULTS: In the groups of cnm-positive and cbm-positive strains, all properties, including collagen binding, adhesion, and invasion were significantly greater than those of the cnm-cbm-negative group. Moreover, MLST revealed three clonal complexes of S. mutans possessing the cbm gene. These three clones showed no close relatedness with clones of strains containing the cnm gene. Among three clones harbouring the cbm gene, two clones belong to serotype k, and appeared to be associated with the pathogenesis of IE due to their strong collagen binding and relatively enhanced abilities to adhere to and invade endothelial cells. However, such properties were relatively weak in the other non-serotype k clone possessing the cbm gene. CONCLUSIONS: MLST indicated a difference in evolution between S. mutans strains with the cbm gene and those with the cnm gene. In addition, this technique also suggested the importance of cbm-positive S. mutans clones relative to the pathogenesis of IE.

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  • Potential involvement of collagen-binding proteins of Streptococcus mutans in infective endocarditis. Reviewed International journal

    R Nomura, S Naka, H Nemoto, S Inagaki, K Taniguchi, T Ooshima, K Nakano

    Oral diseases   19 ( 4 )   387 - 93   2013.5

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    OBJECTIVE: Streptococcus mutans, a major pathogen of dental caries, is considered to be one of the causative agents of infective endocarditis (IE). Two types of cell surface collagen-binding proteins, Cnm and Cbm, have been identified in the organism. The aim of the present study was to analyze these proteins as possible etiologic factors for IE. MATERIALS AND METHODS: The binding activities of S. mutans strains to collagen types I, III, and IV were analyzed relative to the presence of Cnm and Cbm, as were their adhesion and invasion properties with human umbilical vein endothelial cells (HUVEC). In addition, distributions of the genes encoding Cnm and Cbm in S. mutans-positive heart valve specimens extirpated from IE and non-IE patients were analyzed by PCR. RESULTS: Most of the Cbm-positive strains showed higher levels of binding to type I collagen as well as higher rates of adhesion and invasion with HUVEC as compared to the Cnm-positive strains. Furthermore, the gene encoding Cbm was detected significantly more frequently in heart valve specimens from IE patients than from non-IE patients. CONCLUSIONS: These results suggest that the collagen-binding protein Cbm of S. mutans may be one of the potential important factor associated with the pathogenesis of IE.

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  • Horizontal impaction of primary mandibular bilateral central incisors identified in 2-year-8-month-old girl Reviewed

    Rena Okawa, Shuhei Naka, Kazuyo Fujita, Suguru Sakashita, Ryota Nomura, Kazuhiko Nakano

    Pediatric Dental Journal   23 ( 1 )   66 - 69   2013.4

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  • Long-term follow-up of delayed development of maxillary right second premolar with inversely positioned corresponding primary molar Reviewed

    Rena Okawa, Shuhei Naka, Ayuchi Kojima, Hidekazu Sasaki, Ryota Nomura, Kazuhiko Nakano

    Pediatric Dental Journal   23 ( 1 )   62 - 65   2013.4

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    DOI: 10.1016/j.pdj.2013.03.009

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  • Distribution and molecular characterization of Porphyromonas gulae carrying a new fimA genotype. Reviewed International journal

    Yoshie Yamasaki, Ryota Nomura, Kazuhiko Nakano, Hiroaki Inaba, Masae Kuboniwa, Norihiko Hirai, Mitsuyuki Shirai, Yukio Kato, Masaru Murakami, Shuhei Naka, Soichi Iwai, Michiyo Matsumoto-Nakano, Takashi Ooshima, Atsuo Amano, Fumitoshi Asai

    Veterinary microbiology   161 ( 1-2 )   196 - 205   2012.12

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    Porphyromonas gulae is a gram-negative black-pigmented anaerobe which is known to be a pathogen for periodontitis in dogs. Approximately 41kDa filamentous appendages on the cell surface (FimA) encoded by the fimA gene are regarded as important factors associated with periodontitis. The fimA genotype was classified into two major types and strains in type B were shown to be more virulent than those in type A. In the present study, we characterized a strain with a novel fimA genotype and designated it as type C. The putative amino acid sequence was shown to be similar to the genotype IV fimA of Porphyromonas gingivalis, a major pathogen of human periodontitis. Analyses using an oral squamous cell carcinoma cell line derived from tongue primary lesions revealed that the type C strain inhibited proliferation and scratch closure more than genotype A and B strains. In addition, experiments using a mouse abscess model demonstrated that the type C strain could induce much higher systemic inflammation when compared with strains of the other genotypes. Furthermore, molecular analyses of oral swab specimens collected from dogs demonstrated that the detection frequencies of P. gulae and the genotype C in the periodontitis group were significantly higher than those in the periodontally healthy group. These results suggest that FimA of P. gulae is diverse with the virulence of genotype C strains the highest and that molecular identification of genotype C P. gulae could be a possible useful marker for identifying dogs at high risk of developing periodontitis.

    DOI: 10.1016/j.vetmic.2012.07.026

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  • Distribution of periodontopathic bacterial species in dogs and their owners Reviewed

    Y. Yamasaki, R. Nomura, K. Nakano, S. Naka, M. Matsumoto-Nakano, F. Asai, T. Ooshima

    Archives of Oral Biology   57 ( 9 )   1183 - 1188   2012.9

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    Objective: Presently, a large number of individuals consider their companion animals as family members and have close contact with them in daily life. The purpose of the present study was to analyze the distribution of periodontopathic bacterial species in oral specimens taken from dogs and their owners. Design: Dental plaque specimens were collected from 66 dogs and 81 members of 64 families who came to an animal clinic or dog training school in Okayama, Japan, in 2011. Bacterial DNA was extracted from each specimen and PCR analyses using primers specific for 11 periodontopathic species, Porphyromonas gingivalis, Porphyromonas gulae, Treponema denticola, Tannerella forsythia, Capnocytophaga ochracea, Capnocytophaga sputigena, Prevotella intermedia, Prevotella nigrescens, Aggregatibacter actinomycetemcomitans, Campylobacter rectus, and Eikenella corrodens were performed. Results: P. gulae (71.2%), T. forsythia (77.3%), and C. rectus (66.7%) were frequently found in the dogs, whereas the detection rates of those species in humans were less frequent at 16.0%, 30.9%, and 21.0%, respectively. P. gulae was identified in 13 human subjects and each of their dogs was also positive for the species. Furthermore, E. corrodens and T. denticola in specimens obtained from dogs were correlated with their presence in specimens from owners who had close contact with them. Conclusions: These results suggest that several periodontopathic species could be transmitted between humans and their companion dogs, though the distribution of periodontopathic species in both is generally different. © 2012 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.archoralbio.2012.02.015

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  • Identification and characterization of a collagen-binding protein, Cbm, in Streptococcus mutans. Reviewed International journal

    R Nomura, K Nakano, S Naka, H Nemoto, K Masuda, J Lapirattanakul, S Alaluusua, M Matsumoto, S Kawabata, T Ooshima

    Molecular oral microbiology   27 ( 4 )   308 - 23   2012.8

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    Streptococcus mutans, a major pathogen of dental caries, is occasionally isolated from the blood of patients with infective endocarditis. Bacterial attachment of exposed collagen tissue in the impaired endothelium is an important step in the onset of infective endocarditis. In our previous studies, some S. mutans strains were shown to possess collagen-binding activities and most of them had an approximately 120-kDa cell-surface collagen-binding protein called Cnm. However, several strains without Cnm proteins show collagen-binding properties. In the present study, another collagen-binding protein, Cbm, was characterized and its coding gene cbm was sequenced in these strains. The amino acid alignment in the putative collagen-binding domain of Cbm was shown to have approximately 80% identity and 90% similarity to the comparable region of Cnm. Cbm-deficient isogenic mutant strains constructed by insertional inactivation of the cbm gene, lacked collagen-binding properties, which were recovered in the complemented mutant. Analyses of a large number of clinical isolates from Japan, Thailand and Finland revealed that cbm-positive strains were present in all of these countries and that cnm-positive and cbm-positive strains were detected in the oral cavity of approximately 10 and 2% of systemically healthy subjects, respectively. In addition, cnm-positive strains were predominantly identified in the serotype f group, whereas cbm-positive strains were frequently detected in serotype k. These results suggest that Cbm as well as Cnm are major cell surface proteins of S. mutans associated with binding to type I collagen and predominantly identified in serotype k strains.

    DOI: 10.1111/j.2041-1014.2012.00649.x

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  • Diversity of fimbrillin among Porphyromonas gulae clinical isolates from Japanese dogs. Reviewed

    Ryota Nomura, Mitsuyuki Shirai, Yukio Kato, Masaru Murakami, Kazuhiko Nakano, Norihiko Hirai, Tetsuya Mizusawa, Shuhei Naka, Yoshie Yamasaki, Michiyo Matsumoto-Nakano, Takashi Ooshima, Fumitoshi Asai

    The Journal of veterinary medical science   74 ( 7 )   885 - 91   2012.7

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    Porphyromonas gulae, a gram-negative black-pigmented anaerobe, is a pathogen for periodontitis in dogs. An approximately 41-kDa fimbrial subunit protein (FimA) encoded by fimA is regarded as associated with periodontitis. In the present study, the fimA genes of 17 P. gulae strains were sequenced, and classified into two major types. The generation of phylogenetic trees based on the deduced amino acid sequence of FimA of P. gulae strains along with sequences from several strains of Porphyromonas gingivalis, a major cause of human periodontitis, revealed that the two types of FimA (types A and B) of P. gulae were similar to type I FimA and types II and III FimA of P. gingivalis, respectively. A PCR system for classification was established based on differences in the nucleotide sequences of the fimA genes. Analysis of 115 P. gulae-positive oral swab specimens from dogs revealed that 42.6%, 22.6%, and 26.1% of them contained type A, type B, and both type A and B fimA genes, respectively. Experiments with a mouse abscess model demonstrated that the strains with type B fimA caused significantly greater systemic inflammation than those with type A. These results suggest that the FimA proteins of P. gulae are diverse with two major types and that strains with type B fimA could be more virulent.

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  • Amoxicillin-resistant oral streptococci identified in dental plaque specimens from healthy Japanese adults. Reviewed International journal

    Katsuhiko Masuda, Hirotoshi Nemoto, Kazuhiko Nakano, Shuhei Naka, Ryota Nomura, Takashi Ooshima

    Journal of cardiology   59 ( 3 )   285 - 90   2012.5

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    BACKGROUND: Infective endocarditis (IE) is known to be a life-threatening disease and invasive dental procedures are considered to be important factors. Oral amoxicillin (AMPC) is widely used for prophylaxis in patients with heart disorders who are at risk for IE. However, there is only limited information regarding the inhibition of oral bacteria by AMPC. METHODS AND RESULTS: Dental plaque specimens were obtained from 120 healthy Japanese adult subjects, then diluted and streaked onto selective medium for oral streptococci. The minimum inhibitory concentration (MIC) of AMPC was evaluated using a macro-dilution method by Clinical Laboratory Standard Institute (2006). Seven strains with an MIC of AMPC of 16μg/mL or more were isolated from 5 subjects. The bacterial species were confirmed by sequence analysis of 16S rRNA from each strain, which demonstrated that most were Streptococcus sanguinis, followed by Streptococcus oralis. Dental plaque specimens collected from these 5 subjects again after an interval of 2-3 months possessed no strains with an MIC of AMPC of 16μg/mL or more. CONCLUSIONS: These findings suggest that strains with a high MIC of AMPC are present in the oral cavities of Japanese adults, though they may be transient rather than inhabitants.

    DOI: 10.1016/j.jjcc.2011.12.004

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  • Involvement of a periodontal pathogen, Porphyromonas gingivalis on the pathogenesis of non-alcoholic fatty liver disease. Reviewed International journal

    Masato Yoneda, Shuhei Naka, Kazuhiko Nakano, Koichiro Wada, Hiroki Endo, Hironori Mawatari, Kento Imajo, Ryota Nomura, Kazuya Hokamura, Masafumi Ono, Shogo Murata, Iwai Tohnai, Yoshio Sumida, Toshihide Shima, Masae Kuboniwa, Kazuo Umemura, Yoshinori Kamisaki, Atsuo Amano, Takeshi Okanoue, Takashi Ooshima, Atsushi Nakajima

    BMC gastroenterology   12   16 - 16   2012.2

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    BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome that is closely associated with multiple factors such as obesity, hyperlipidemia and type 2 diabetes mellitus. However, other risk factors for the development of NAFLD are unclear. With the association between periodontal disease and the development of systemic diseases receiving increasing attention recently, we conducted this study to investigate the relationship between NAFLD and infection with Porphyromonas gingivalis (P. gingivalis), a major causative agent of periodontitis. METHODS: The detection frequencies of periodontal bacteria in oral samples collected from 150 biopsy-proven NAFLD patients (102 with non-alcoholic steatohepatitis (NASH) and 48 with non-alcoholic fatty liver (NAFL) patients) and 60 non-NAFLD control subjects were determined. Detection of P. gingivalis and other periodontopathic bacteria were detected by PCR assay. In addition, effect of P. gingivalis-infection on mouse NAFLD model was investigated. To clarify the exact contribution of P. gingivalis-induced periodontitis, non-surgical periodontal treatments were also undertaken for 3 months in 10 NAFLD patients with periodontitis. RESULTS: The detection frequency of P. gingivalis in NAFLD patients was significantly higher than that in the non-NAFLD control subjects (46.7% vs. 21.7%, odds ratio: 3.16). In addition, the detection frequency of P. gingivalis in NASH patients was markedly higher than that in the non-NAFLD subjects (52.0%, odds ratio: 3.91). Most of the P. gingivalis fimbria detected in the NAFLD patients was of invasive genotypes, especially type II (50.0%). Infection of type II P. gingivalis on NAFLD model of mice accelerated the NAFLD progression. The non-surgical periodontal treatments on NAFLD patients carried out for 3 months ameliorated the liver function parameters, such as the serum levels of AST and ALT. CONCLUSIONS: Infection with high-virulence P. gingivalis might be an additional risk factor for the development/progression of NAFLD/NASH.

    DOI: 10.1186/1471-230X-12-16

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  • The collagen-binding protein of Streptococcus mutans is involved in haemorrhagic stroke. Reviewed International journal

    Kazuhiko Nakano, Kazuya Hokamura, Naho Taniguchi, Koichiro Wada, Chiho Kudo, Ryota Nomura, Ayuchi Kojima, Shuhei Naka, Yoshinori Muranaka, Min Thura, Atsushi Nakajima, Katsuhiko Masuda, Ichiro Nakagawa, Pietro Speziale, Nobumitsu Shimada, Atsuo Amano, Yoshinori Kamisaki, Tokutaro Tanaka, Kazuo Umemura, Takashi Ooshima

    Nature communications   2   485 - 485   2011.9

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    Although several risk factors for stroke have been identified, one-third remain unexplained. Here we show that infection with Streptococcus mutans expressing collagen-binding protein (CBP) is a potential risk factor for haemorrhagic stroke. Infection with serotype k S. mutans, but not a standard strain, aggravates cerebral haemorrhage in mice. Serotype k S. mutans accumulates in the damaged, but not the contralateral hemisphere, indicating an interaction of bacteria with injured blood vessels. The most important factor for high-virulence is expression of CBP, which is a common property of most serotype k strains. The detection frequency of CBP-expressing S. mutans in haemorrhagic stroke patients is significantly higher than in control subjects. Strains isolated from haemorrhagic stroke patients aggravate haemorrhage in a mouse model, indicating that they are haemorrhagic stroke-associated. Administration of recombinant CBP causes aggravation of haemorrhage. Our data suggest that CBP of S. mutans is directly involved in haemorrhagic stroke.

    DOI: 10.1038/ncomms1491

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  • Characterization of aortic aneurysms in cardiovascular disease patients harboring Porphyromonas gingivalis Reviewed

    K Nakano, K Wada, R Nomura, H Nemoto, H Inaba, A Kojima, S Naka, K Hokamura, T Mukai, A Nakajima, K Umemura, Y Kamisaki, H Yoshioka, K Taniguchi, A Amano, T Ooshima

    Oral Diseases   17 ( 4 )   370 - 378   2011.5

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    DOI: 10.1111/j.1601-0825.2010.01759.x

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  • Successful application of atelocollagen for treatment of perforated teeth. Reviewed International journal

    Katsuhiko Masuda, Kazuhiko Nakano, Rena Okawa, Shuhei Naka, Michiyo Matsumoto, Takashi Ooshima

    The Journal of clinical pediatric dentistry   36 ( 1 )   1 - 4   2011

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    OBJECTIVE: Cervical or furcal root perforation is a serious clinical problem and one of its treatment modalities is perforation repair with composite resin. However, many cases still progress in inevitable extraction. When primary teeth are affected, early tooth loss can cause problems related to the eruption space for the permanent successors. The aim of the present study was to evaluate a novel clinical treatment method for perforated teeth. STUDY DESIGN: Atelocollagen was applied to perforated furcal and cervical areas of 13 primary teeth in 13 children aged 4-9 years and 8 permanent teeth in 8 adults aged 35-69 years after debridement with an electric knife. Thereafter the final restorations were performed after confirming good tooth conditions. Clinical evaluations were performed at follow-up examinations at approximately 3-month intervals. RESULTS: None of the treated primary teeth showed any clinical problems throughout the observation period, with eruption of the permanent successors noted in 7 cases. In the permanent teeth, no clinical problems were identified in any of the cases during follow-up periods of 10-60 months. CONCLUSION: This novel method may enable preservation of perforated primary teeth for a longer duration.

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  • Successful application of molecular biological technique for evaluation of changes in periodontopathic bacteria in Japanese children with developmental disabilities Reviewed

    Ardin Arifah Chieko, Nakano Kazuhiko, Yamana Aki, Okawa Rena, Naka Shuhei, Matsumoto Michiyo, Ooshima Takashi

    Ped Dent J   21 ( 1 )   56 - 62   2011

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    Developments in molecular biological techniques enables rapid and easy identification of periodontopathic bacterial species in clinical specimens. However, there are few reports regarding their application for community dentistry. The aim of this study was to show successful application of a molecular biological technique for evaluation of changes in periodontal bacterial species in children at daycare centers. We studied 187 children who received oral examinations in 2009 and 186 who received examinations in 2010, among whom 102 were examined in both years. Clinical parameters regarding periodontal conditions were evaluated and the distribution of 10 periodontopathic species in dental plaque specimens were determined by polymerase chain reaction. Periodontal pocket depth values in the 2010 group were significantly smaller than those in 2009. When the subjects were divided into those with (positive group) and without (negative group) Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, or Campylobacter rectus in 2009, the positive group had significantly smaller periodontal pocket values than the negative group. In addition, the rate of subjects with P.gingivalis, T.denticola, T.forsythia, or C.rectus in the positive group in 2010 was significantly reduced. Our findings demonstrate that molecular biological methods provide more information as compared to a standard clinical examination when evaluating changes of periodontal conditions in the field of community dentistry.

    DOI: 10.11411/pdj.21.56

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  • A case of incidental identification of mesiodens in 1-year-old boy followed for 6 years Reviewed

    Nakano Kazuhiko, Naka Shuhei, Kojima Ayuchi, Nemoto Hirotoshi, Inagaki Satoko, Ooshima Takashi

    Pediatric Dental Journal   21 ( 1 )   73 - 77   2011

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    We present a case of mesiodens identified in a 1-year 9-month-old boy. The patient visited our clinic after receiving a traumatic injury, which caused intrusion of the maxillary right and left primary central incisors. A periapical radiograph revealed no root fractures, though a mesiodens was incidentally found. The intruded teeth naturally moved into their original positions and periodical examinations were scheduled. At 4Y2M, uncommon mesial inclination of the maxillary right primary central incisor was noted. A radiographic examination showed the enlarged dental follicle of the mesiodens, which appeared to cause the inclination, and we planned fenestration when enlargement of the lesion was identified. At 5Y1M, he received another traumatic injury and the maxillary right primary central incisor was exfoliated. At 5Y5M, the mesiodens spontaneously emerged into the oral cavity and a radiographic examination showed prominent rotation of the maxillary right central incisor. Two-thirds of the crown of the mesiodens could be seen at 6Y4M. At 6Y11M, the patient again received a traumatic injury, and intrusion of the maxillary left primary central incisor was observed. At 7Y0M, the mesiodens and maxillary left primary central incisor were extracted under infiltration anesthesia, after which inclination of the axis of the adjacent maxillary right central incisor gradually improved.

    DOI: 10.11411/pdj.21.73

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  • Detection of oral streptococci with collagen-binding properties in saliva specimens from mothers and their children. Reviewed International journal

    Ryota Nomura, Shuhei Naka, Kazuhiko Nakano, Naho Taniguchi, Michiyo Matsumoto, Takashi Ooshima

    International journal of paediatric dentistry   20 ( 4 )   254 - 60   2010.7

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    BACKGROUND: Approximately 10-20% of Streptococcus mutans strains have been reported to possess collagen-binding properties, whereas other species in the oral cavity with those properties remain to be elucidated. Aim. To identify strains with collagen-binding properties and analyse their characteristics in comparison with S. mutans. DESIGN: A total of 110 expectorated saliva specimens were collected from 55 pairs of mothers and their children. Bacterial strains with collagen-binding properties were isolated and the species specified. In addition, strains with collagen-binding properties isolated from mother-child pairs were analysed using molecular biological approaches. RESULTS: The detection frequency of strains with collagen-binding properties was shown to be 40.9%, among which S. salivarius was the most frequently detected, followed by S. mutans. The collagen-binding activity of the S. mutans group was the highest, followed by S. salivarius. In addition, S. mutans and S. salivarius strains from 3 and 1 mother-child pairs, respectively, were shown to be the same clones. CONCLUSIONS: Our results indicate that S. mutans and S. salivarius are major species with collagen-binding properties in the oral cavity, and that strains with such properties may be related to mother-child transmission.

    DOI: 10.1111/j.1365-263X.2010.01047.x

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  • Defect of glucosyltransferases reduces platelet aggregation activity of Streptococcus mutans: analysis of clinical strains isolated from oral cavities. Reviewed International journal

    N Taniguchi, K Nakano, R Nomura, S Naka, A Kojima, M Matsumoto, T Ooshima

    Archives of oral biology   55 ( 6 )   410 - 6   2010.6

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    OBJECTIVE: Streptococcus mutans is a major pathogen of dental caries and occasionally isolated from the blood of patients with infective endocarditis, though the association of its cell-surface glucosyltransferases (GTFB, GTFC, and GTFD) with pathogenicity for infective endocarditis remains to be elucidated. In this study, we investigated the contribution of S. mutans GTFs to platelet aggregation and analysed GTF expression profiles in a large number of clinical oral isolates. DESIGN: The platelet aggregation properties of GTF-defective isogenic mutant strains constructed from S. mutans reference strain MT8148 were evaluated using whole blood and platelet-rich plasma (PRP) taken from mice, as well as human PRP. In addition, GTF expression profiles for 396 S. mutans strains isolated from the oral cavities of 396 subjects were analysed by western blotting using antisera specific for each GTF. RESULTS: The platelet aggregation activities of the GTF-defective isogenic mutants were significantly lower than that of MT8148 when added to a large number of cells. Western blotting revealed no strains without GTF expression, though six strains had alterations of GTFB and GTFC as compared to MT8148. PCR analyses indicated that the gtfB-gtfC region length was approximately 4.5 kb shorter in those strains as compared to MT8148. These were designated as "GTFBC-fusion" strains and they demonstrated lower levels of platelet aggregation. CONCLUSIONS: Our findings indicate that GTFs are associated with platelet aggregation. Although the clinical detection frequency of S. mutans strains with altered expressions is extremely low, GTFBC-fusion strains have activities similar to GTF-defective mutant strains.

    DOI: 10.1016/j.archoralbio.2010.03.017

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  • Molecular characterization of Streptococcus mutans strains containing the cnm gene encoding a collagen-binding adhesin. Reviewed International journal

    K Nakano, R Nomura, N Taniguchi, J Lapirattanakul, A Kojima, S Naka, P Senawongse, R Srisatjaluk, L Grönroos, S Alaluusua, M Matsumoto, T Ooshima

    Archives of oral biology   55 ( 1 )   34 - 9   2010.1

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    OBJECTIVE: Streptococcus mutans, known to be a major pathogen of dental caries, is also considered to cause infective endocarditis. Its 120-kDa Cnm protein binds to type I collagen, which may be a potential virulence factor. In this study, we characterized S. mutans clinical strains focusing on the cnm gene encoding Cnm. DESIGN: A total of 528 S. mutans strains isolated from Japanese, Finnish, and Thai subjects were investigated. Using molecular techniques, the distribution frequency of cnm-positive strains and location of the inserted cnm were analyzed. Furthermore, isogenic mutant strains were constructed by inactivation of the cnm gene, then their biological properties of collagen-binding and glucan-binding were evaluated. Southern hybridization of the genes encoding glucan-binding proteins was also performed. RESULTS: The distribution frequency of cnm-positive strains from Thai subjects was 12%, similar to that previously reported for Japanese and Finnish subjects. Furthermore, the location of insertion of cnm was the same in all cnm-positive clinical isolates. As for the cnm-inactivated mutant strains constructed from 28 clinical isolates, their collagen-binding activity was negligible. In addition, glucan-binding activity in the cnm-positive clinical isolates was significantly reduced and corresponded to a lack of gbpA encoding glucan-binding protein A. CONCLUSIONS: Our results indicate that strains with cnm genes, the most crucial factor for the collagen-binding property of S. mutans, are detectable at similar frequencies over several different geographic locations. In addition, the common properties of these strains are a high level of collagen-binding activity and tendency for a low level of glucan-binding activity.

    DOI: 10.1016/j.archoralbio.2009.11.008

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  • Suspected cerebral gigantism diagnosed by dental examination Reviewed

    OKAWA Rena, MASUDA Katsuhiko, NAKANO Kazuhiko, NAKA Shuhei, MATSUMOTO Michiyo, OOSHIMA Takashi

    Pediatric Dental Journal   19 ( 2 )   247 - 251   2009.9

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    Cerebral gigantism is an overgrowth disorder that occurs from the prenatal stage through childhood and features such clinical symptoms as advanced bone age, macrocephaly, characteristic facial appearance, and learning difficulties. A 4-year 3-month-old girl was referred to our clinic for consultation regarding anterior crossbite and occlusal pain in the molar region. An intraoral examination showed that the mandible was considerably larger than the maxilla. The dental age of the entire dentition estimated from orthopantomogram images was approximately 1 year ahead of chronological age. Cephalometrics analysis demonstrated maxillary protrusion, prominent mandibular protrusion, and vertically severe short face. The size of maxilla was slightly small, whereas that of mandible was above the average. Since height and body weight were above the 97 percentile, the patient was referred to a pediatrician for a general examination prior to dental treatment and diagnosed with suspected cerebral gigantism. As for occlusal pain in the molar region, we considered that it was caused by excessive occlusal pressure. Following application of splinting and several adjustments, the pain gradually disappeared.

    DOI: 10.11411/pdj.19.247

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  • Distribution of periodontopathic bacterial species in Japanese children with developmental disabilities. Reviewed International journal

    Shuhei Naka, Aki Yamana, Kazuhiko Nakano, Rena Okawa, Kazuyo Fujita, Ayuchi Kojima, Hirotoshi Nemoto, Ryota Nomura, Michiyo Matsumoto, Takashi Ooshima

    BMC oral health   9   24 - 24   2009.9

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    BACKGROUND: Recent developments in molecular biological techniques have enabled rapid detection of periodontopathic bacterial species in clinical specimens. Accumulated evidence suggests that detection of specific bacterial species enables identification of subjects at high risk for the onset of periodontitis. We investigated the distribution of 10 selected periodontopathic bacterial species in dental plaque specimens obtained from children with disabilities who were attending daycare centers. METHODS: A total of 187 children (136 boys, 51 girls) aged 1-6 years old and diagnosed with such disabilities as mental retardation, cerebral palsy, and autism, participated in the study. Subgingival dental plaque specimens were collected from the buccal side of the maxillary left second primary molar after a clinical examination. Bacterial DNA was extracted from the specimens and PCR analyses were carried out to detect 10 selected periodontopathic species using specific primers for each. In addition, statistical analyses were performed to analyze the correlations among clinical parameters and the detected species. RESULTS: The most frequently detected species was Capnocytophaga sputigena (28.3%), followed by Aggregatibacter actinomycetemcomitans (20.9%) and Campylobacter rectus (18.2%). Eikenella corrodens, Capnocytophaga ochracea, and Prevotella nigrescence were detected in approximately 10% of the specimens, whereas Treponema denticola, Tannerella forsythia, and Prevotella intermedia were rarely found, and Porphyromonas gingivalis was not detected in any of the subjects. The total numbers of detected species were positively correlated with the age of the subjects. There were 10 subjects with positive reactions for T. denticola and/or T. forsythia, in whom the total number of bacterial species was significantly higher as compared to the other subjects. Furthermore, subjects possessing C. rectus showed significantly greater values for periodontal pocket depth, gingival index, and total number of species. CONCLUSION: We found that approximately one-fourth of the present subjects with disabilities who possessed at least one of T. denticola, T. forsythia, and C. rectus were at possible risk for periodontitis. Follow-up examinations as well as preventive approaches should be utilized for such individuals.

    DOI: 10.1186/1472-6831-9-24

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  • 歯科衛生士とともに学ぶ GPのための小児歯科ケーススタディ

    仲野 和彦, 権 暁成( Role: Joint author ,  乳歯用既製金属冠修復)

    デンタルダイヤモンド社  2024.4 

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  • 子どものお口の発育段階別で答える小児歯科のQ&A27

    浜野, 美幸, 岡, 暁子, 大川, 玲奈( Role: Joint author)

    デンタルダイヤモンド社  2023.7  ( ISBN:9784885105708

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    Total pages:149p   Language:Japanese

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  • 臨床医のための小児歯科 BASIC & CASEBOOK

    田中晃伸,仲野和彦,権暁成( Role: Contributor ,  う蝕抑制のための薬剤・充填材料)

    デンタルダイヤモンド社  2022.6 

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    Total pages:273   Responsible for pages:32〜33   Language:Japanese Book type:Textbook, survey, introduction

  • 臨床医のための小児歯科Basic&casebook

    田中, 晃伸, 仲野, 和彦, 権, 暁成( Role: Joint author)

    デンタルダイヤモンド社  2022.6  ( ISBN:9784885105364

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    Total pages:273p   Language:Japanese

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  • 子どもの健やかなお口をつくる

    木本茂成,福本敏( Role: Contributor ,  歯の形態異常(歯冠部、歯髄・歯根部))

    松風歯科クラブ  2021.1 

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    Total pages:179   Responsible for pages:48〜53   Language:Japanese Book type:Scholarly book

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  • 歯科衛生士のための小児歯科のきほん

    仲野和彦, 権 暁成, 田中晃伸( Role: Contributor ,  歯周疾患)

    デンタルダイヤモンド社  2020.12 

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    Total pages:126   Responsible for pages:44〜47   Language:Japanese Book type:Scholarly book

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  • 小児歯科はじめましょう

    田中晃伸, 仲野和彦, 権 暁成( Role: Contributor ,  過剰埋伏歯診断,過剰埋伏歯の抜歯,歯髄保護)

    デンタルダイヤモンド社  2020.6 

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    Total pages:209   Responsible for pages:40〜41, 110〜111, 128〜129   Language:Japanese Book type:Textbook, survey, introduction

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MISC

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Presentations

  • むし歯の謎を知る

    仲 周平

    高校生のための大学講座  2022.8.10 

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    Event date: 2022.8.9 - 2022.8.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:教育連携協議会教育連携事業   Country:Japan  

  • Streptococcus mutans の菌体表層に発現するコラーゲン結合タンパクの IgA 腎症様腎炎発症への関連性

    仲 周平

    第45回 IgA 腎症研究会  2022.1.29  日本 IgA 腎症研究会

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    Event date: 2022.1.29

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東京   Country:Japan  

  • ラット齲蝕モデルにおけるIgA腎症様腎炎発症に関する検討

    仲 周平

    第43回 IgA 腎症研究会  2020.2  日本 IgA 腎症研究会

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    Event date: 2020.2

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:東京   Country:Japan  

  • 意外と知らない小児の口腔疾患 Invited

    仲 周平

    第38回日本小児歯科学会近畿地方会大会  2019.10  日本小児歯科学会近畿地方会

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    Event date: 2019.10

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:大阪  

  • 意外と知らない小児の口腔疾患

    仲 周平

    第38回日本小児歯科学会近畿地方会大会  2019.10 

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    Event date: 2019.10

    Presentation type:Oral presentation (invited, special)  

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  • Streptococcus mutans が引き起こす非アルコール性脂肪肝炎悪化メカニズムの追究 Invited

    仲 周平

    第57回日本小児学会大会  2019.6  日本小児歯科学会

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    Event date: 2019.6

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:札幌市   Country:Japan  

  • Streptococcus mutans が引き起こす非アルコール性脂肪肝炎増悪化メカニズムの追究

    仲 周平

    第57回日本小児歯科学会大会  2019.6 

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    Event date: 2019.6

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  • 口腔細菌が非アルコール性脂肪肝炎発症に関連する可能性 Invited

    仲 周平

    第36回小児医療センター合同カンファレンス  2019.3  岡山大学病院小児医療センター

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    Event date: 2019.3

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:岡山大学   Country:Japan  

  • ミュータンスレンサ球菌がIgA腎症発症へ及ぼす可能性について Invited

    仲 周平

    岡山大学歯学部小児歯科学講座同門会講演会  2019.1  岡山大学歯学部小児歯科学講座同門会

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    Event date: 2019.1

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:岡山県   Country:Japan  

  • 原因不明の乳歯早期脱落症例 Invited

    仲 周平

    第1回侵襲性歯周炎センタークリニカルカンファレンス  2018.12  岡山大学歯学部歯周病学分野

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    Event date: 2018.12

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:岡山大学   Country:Japan  

  • 口腔細菌とからだのの健康(むし歯の原因と予防) Invited

    仲 周平

    吉備創生カレッジ医療福祉講座  2018.5  吉備創生カレッジ医療福祉

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    Event date: 2018.5

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:岡山県   Country:Japan  

  • 非アルコール性脂肪肝炎における口腔細菌の役割

    仲 周平

    第52回日本小児歯科学会大会  2014.5 

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    Event date: 2014.5

    Presentation type:Oral presentation (invited, special)  

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  • 炎症性腸疾患と口腔内および口唇肉芽腫性病変との関連

    仲 周平

    第55回小児医療センター合同カンファレンス  2023.1 

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    Presentation type:Public lecture, seminar, tutorial, course, or other speech  

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  • むし歯の謎を知る

    仲 周平

    高校生のための大学講座  2022.8 

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    Presentation type:Public lecture, seminar, tutorial, course, or other speech  

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  • 注意すべき乳歯の早期脱落

    仲 周平

    小児医療センター合同カンファレンス  2020.1 

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  • 口腔細菌が非アルコール性脂肪肝炎発症に関連する可能性

    仲 周平

    第36回小児医療センター合同カンファレンス  2019.3 

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  • ミュータンスレンサ球菌がIgA腎症発症へ及ぼす可能性について

    仲 周平

    岡山大学歯学部小児歯科学講座同門会講演会  2019.1 

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    Presentation type:Public lecture, seminar, tutorial, course, or other speech  

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  • 原因不明の乳歯早期脱落症例

    仲 周平

    第1回侵襲性歯周炎センタークリニカルカンファレンス  2018.12 

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  • 口腔細菌とからだの健康(むし歯の原因と予防)

    仲 周平

    吉備創生カレッジ医療福祉講座  2018.5 

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    Presentation type:Public lecture, seminar, tutorial, course, or other speech  

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  • 小児の侵襲性歯周炎が全身に及ぼす影響について

    仲 周平

    第29回小児医療センター合同カンファレンス  2018.1 

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  • 口腔細菌が誘発する NASH 悪化メカニズムの解明

    仲 周平

    第22回ARCOCSセミナー 

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Awards

  • 第33回台湾小児歯科学会大会 最優秀発表賞

    2024.6  

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  • 第46回IgA腎症研究会学術集会 優秀演題賞

    2023.1  

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  • 日本小児歯科学会学術賞(Lion Awrad)

    2019.6   日本小児歯科学会  

    仲 周平

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    Award type:Award from Japanese society, conference, symposium, etc. 

  • 日本小児歯科学会 学術賞(Lion Award)

    2019.6  

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  • 日本小児歯科学会優秀発表賞

    2018.5   日本小児歯科学会  

    仲 周平

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

  • 日本小児歯科学会 優秀発表賞

    2018.5  

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  • JADR 学術大会学術奨励賞

    2017.11   JADR  

    仲 周平

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    Award type:Award from international society, conference, symposium, etc.  Country:Japan

  • JADR学術大会 学術奨励賞

    2017.11  

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  • 大阪大学歯学部附属病院長表彰

    2016.3   大阪大学歯学部附属病院  

    仲 周平

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    Country:Japan

  • 大阪大学歯学部附属病院長表彰

    2016.3  

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  • 日本小児歯科学会奨励賞

    2014.5   日本小児歯科学会  

    仲 周平

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

  • 日本小児歯科学会 奨励賞

    2014.5  

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  • 日本小児歯科学会近畿地方会大会優秀発表賞

    2011.10   日本小児歯科学会近畿地方会  

    仲 周平

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

  • 日本小児歯科学会近畿地方会大会 優秀発表賞

    2011.10  

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  • 日本小児歯科学会デンツプライ賞

    2010.5   日本小児歯科学会  

    仲 周平

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

  • 日本小児歯科学会 デンツプライ賞

    2010.5  

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  • 日本小児歯科学会近畿地方会大会優秀発表賞

    2009.10   日本小児歯科学会近畿地方会  

    仲 周平

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

  • 日本小児歯科学会近畿地方会大会 優秀発表賞

    2009.10  

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Research Projects

  • S. mutans コラーゲン結合タンパクに着目した IgA 腎症発症機構の解明

    Grant number:23K09435  2023.04 - 2026.03

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    仲 周平, 仲野 和彦, 仲野 道代

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    Grant amount:\4550000 ( Direct expense: \3500000 、 Indirect expense:\1050000 )

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  • 口腔バイオフィルム感染症制御法確立のための新規ターゲットタンパクの解析

    Grant number:23H03115  2023.04 - 2026.03

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    仲野 道代, 仲 周平, 稲葉 裕明

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    Grant amount:\18460000 ( Direct expense: \14200000 、 Indirect expense:\4260000 )

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  • う蝕原性細菌のコラーゲン結合能に着目した低中所得国の全身疾患低減に向けた新戦略

    Grant number:21KK0160  2021.10 - 2025.03

    日本学術振興会  科学研究費助成事業  国際共同研究加速基金(国際共同研究強化(B))

    仲野 和彦, 野村 良太, 大川 玲奈, 又吉 紗綾, 仲野 道代, 仲 周平, 吉田 翔, 後藤 花奈

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    Grant amount:\18980000 ( Direct expense: \14600000 、 Indirect expense:\4380000 )

    う蝕原性細菌 Streptococcus mutansは、感染性心内膜炎の起炎菌としても知られている。近年、S. mutansには菌体表層にコラーゲン結合タンパクであるCnmを発現している株が存在し、感染性心内膜炎だけでなく脳血管疾患、腎疾患、非アルコール性脂肪肝炎などの全身疾患にも関与することが明らかになってきている。そこで、Cnm陽性S. mutansの保菌者の分布を詳細に分析することが、ある種の全身疾患の低減に役立つ可能性があるのではないかと考えた。本研究では、日本の各地域において口腔サンプルを採取してCnm陽性S. mutansの分布に関する調査を行うことにした。
    研究を行うに当たり、歯学部が存在する全国の国立大学に共同研究への参画を依頼したところ、10大学においてご協力いただけることになった。これらのうち、北海道大学、大阪大学、岡山大学、広島大学の4つの歯学部附属病院において患者の同意のもとで口腔サンプルの採取を開始し、現在までに143名の患者の口腔サンプルからS. mutansを分離した。これらの患者について、1名につき5株のS. mutansをピックアップしてゲノムDNAを抽出し、PCR法によりCnmをコードする遺伝子の検出を行った。その結果、Cnm陽性S. mutansの保菌者は143名のうち16名(11.2%)であり、各施設におけるCnm陽性S. mutansの検出率は北海道大学で25.0%(12名中3名)、大阪大学で9.1%(33名中3名)岡山大学で12.5%(32名中4名)広島大学で9.1%(66名中6名)であることが示された。

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  • 口腔細菌叢のメタゲノム解析による非アルコール性脂肪肝炎発症機序解明と新規予防戦略

    Grant number:21K19604  2021.07 - 2024.03

    日本学術振興会  科学研究費助成事業  挑戦的研究(萌芽)

    仲野 道代, 仲 周平, 高木 章乃夫

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    Grant amount:\6500000 ( Direct expense: \5000000 、 Indirect expense:\1500000 )

    脂肪肝を呈する小児患者の口腔内細菌叢をメタゲノム解析によって分析し、高頻度に存在する歯周病原細菌および口腔レンサ球菌について網羅的に解析を行い、原因となる菌のスクリーニングを行う。本研究は、非アルコール性脂肪肝炎発症と口腔細菌との関連を明らかとし新たな予防法を確立することを目的とする。
    非アルコール性脂肪肝炎 (NASH)モデルマウスを用いた検討を行い、重度な NASH 患者からの口腔内から分離したS. mutans 株を頸静脈より投与し、菌投与後 16 週後に、体重の測定とマウス心臓から血液を採取、屠殺後、肝臓を摘出した。肝臓は,菌投与群では、菌非投与群のものと比較して明らかに肥大しており,菌投与群の肝重量は菌非投与群と比較して有意に高い値を示した。また、血液検査所見では、菌投与群では菌非投与群と比較して、総コレステロール、遊離コレステロール、LDL、HDL、コリンエステラーゼなどの値の上昇が認められ、脂質代謝異常が生じていることが明らかとなった。また、AST、ALT、ALP、LAP、鉄などの値の上昇も認められ、肝機能の障害が疑われた。さらに肝臓組織のヘマトキシリンエオジン染色像では,菌非投与群と比較して大滴性の脂肪沈着と局所の炎症性細胞の浸潤が顕著であった.一方で,菌非投与群では脂肪沈着はあったものの,小滴性の脂肪沈着であった.また,マッソントリクローム染色像では,菌投与群の肝実質の局所において青く染色された線維化像が観察されたが,菌非投与群では観察されなかった.
    以上の結果より、高脂肪食を与えインスリン抵抗性が生じているNASHモデルマウスに,NASH患者から分離されたS. mutans株を頸静脈より投与すると,NASHを発症することが明らかとなった.今後はこれらの発症メカニズムについて、S. mutansの保有する表層タンパクについて検討する予定である。

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  • 膜タンパクをターゲットとした新たな口腔バイオフィルム制御法の確立

    Grant number:20H03897  2020.04 - 2023.03

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    仲野 道代, 仲 周平, 稲葉 裕明

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    Grant amount:\17290000 ( Direct expense: \13300000 、 Indirect expense:\3990000 )

    バイオフィルム形成は、細胞―細胞間情報伝達機構であるクオラムセンシングにより制御されており、必要な栄養素を取り込み不要な物質を排出する役割を持つ膜タンパクが関与しているがその詳細は不明である。本研究では、分子生物学的手法を駆使して齲蝕および歯周病の主要な起炎菌における膜タンパクの役割を明らかにすることを目的としている。
    S. mutans UA159 株のデータベースから、バイオフィルム形成に関連すると推定されるABC 膜輸送体をコードするSMU _1519 遺伝子を抽出した。SMU _1519の上流および下流領域、およびスペクチノマイシン耐性カセット断片をPCRにて増幅した。オーバーラップPCRで3つのDNA断片を連結させ、精製した。PCR産物をMT8148 株に形質転換することによりSMU _1519欠失変異株(Δ1519株)を作製し、実験に供試した。これらの菌株を対数増殖期まで培養し,RNA抽出を行い,RNA シーケンシングを行った。親株と比較して,遺伝子欠失変異株で2倍以上の変化を認めた遺伝子の解析を行った。その結果、MT8148株と比較し,SMU_1519 遺伝子欠失株において2倍以上発現が抑制した遺伝子は,ガラクトースやラクトースの代謝に関与するlac遺伝子を含む46種類であった。2倍以上発現が上昇した遺伝子は,アンモニアのトランスポーターであるnrgAを含む56種類であった。また,CSP添加によってSMU_1519 遺伝子の発現に変化は認めなかった。以上の結果から、SMU_1519 遺伝子欠失によって糖代謝に重要な役割を果たすlacオペロンの発現が抑制されることから,SMU_1519 遺伝子は増殖能やバイオフィルム形成に関与するシグナル伝達系によって制御されていることが示唆された。

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  • 歯科領域からの革新的治療法の開発を目指した口腔細菌に起因するIgA腎症の病態解明

    Grant number:20K10225  2020.04 - 2023.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    仲 周平, 仲野 和彦, 仲野 道代

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    Grant amount:\4290000 ( Direct expense: \3300000 、 Indirect expense:\990000 )

    これまで、IgA腎症患者の唾液中にはコラーゲン結合能を有する Streptococcus mutans が高頻度で存在しており、これら菌株を保有する患者では、齲蝕経験歯数やタンパク尿の値が有意に高いことが報告されている。本研究の目的は、S. mutans の関連するIgA腎症発症のメカニズムを明らかにすることである。まず、IgA腎症患者より分離したコラーゲン結合能を有する S. mutans をラット頸静脈より投与し、15、30、45および60日後に尿を採取し、成分分析を行った。その結果、タンパク尿は菌投与後30日に非投与群と比較して有意に高い値を認めた。PAS染色像では、投与後30および45日の菌投与群では非投与群と比較してメサンギウム細胞および基質の増殖が認められた。一方で、投与後60日ではこれらの所見は認められなかった。さらに蛍光免疫染色像から、投与後30および45日の菌投与群のメサンギウム領域において、IgAおよびC3の有意な沈着が認められ、メサンギウム領域に高電子密度物質の沈着も確認された。ラット齲蝕モデルを用いた検討では、同 S. mutans 菌株をラット口腔内に定着させ齲蝕を誘発させた結果、菌投与群のプラークスコアと齲蝕スコアは非投与群と比較して有意に高い値を示した。菌投与群では、血尿陽性率は高く、PAS染色像では、メサンギウム細胞および基質の増殖が認められた。さらに蛍光免疫染色像では、メサンギウム領域において、IgAおよびC3の有意な沈着が確認された。
    これらの結果から、ラットモデルにおいてIgA腎症患者より分離した S. mutans を頸静脈より投与した場合は、一過性に IgA腎症様腎炎の発症を認め、ラット口腔内に同菌株を定着させ重度齲蝕を誘発した場合には、長期間ラット体内に持続的に菌が侵入することでIgA腎症用様腎炎が発症することが明らかとなった。

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  • Mechanism of aggravation of IgA nephropathy by mutans streptococci

    Grant number:17K11959  2017.04 - 2020.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    Naka Shuhei

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    Grant amount:\4680000 ( Direct expense: \3600000 、 Indirect expense:\1080000 )

    IgA nephropathy is the most common type of chronic glomerulonephritis and affected patients with a poor prognosis can progress to terminal-stage renal failure. However, the details of the causes and associated mechanisms remain unclear. Streptococcus mutans strains with a collagen-binding property are frequently detected in the oral cavity of IgAN patients. We investigated IgA nephropathy caused by such strains using a rat caries model. Rats were inoculated once daily for 5 consecutive days with a cell suspension containing an S. mutans strain with collagen binding property isolated from the oral cavity of an IgA nephropathy patient. At 32 weeks after inoculation, severe dental caries were observed and histopathological examinations of renal glomeruli revealed characteristic findings of IgA nephropathy-like nephritis. These results suggest that severe caries induced by S. mutans with collagen binding may be associated with induction of IgA nephropathy-like nephritis.

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  • Construction of global standard molecular epidemiological method for identification of the children at risk for severe dental caries

    Grant number:15H05300  2015.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    Nakano Kazuhiko, LAPIRATTANAKUL Jinthana

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    Grant amount:\15730000 ( Direct expense: \12100000 、 Indirect expense:\3630000 )

    Saliva specimens were taken from 3- and 4-year-old Thai children attending a kindergarten and nursery school in Bangkok, Thailand, from which Streptococcus mutans and Lactobacillus species were isolated using selective medium for each. Findings obtained from the S. mutans isolates provided new data to be added to a previously constructed multilocus sequence typing (MLST) scheme, which revealed the possibility of the correlation of a specific group of strains with clinical findings related to dental caries. As for the Lactobacillus species, Lactobacillus fermentus was shown to be associated with severe dental caries, thus several strains were classified using an MLST scheme, with novel sequence types revealed.

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  • Basic and clinical approaches for dental problems associated with skeletal diseases

    Grant number:15K11364  2015.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    OKAWA RENA, NAKANO Kazuhiko, OZONO Keiichi, KITAOKA Taichi, NAKANO Michiyo

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    Grant amount:\4680000 ( Direct expense: \3600000 、 Indirect expense:\1080000 )

    The purpose of this study was to investigate dental problems related to skeletal diseases with basic and clinical approaches. A nationwide dental survey revealed that dentinogenesis imperfecta is a major dental problem occurring in 60% of patients affected by osteogenesis imperfecta. In those patients, a permanent successor often emerges into the oral cavity without resorption of the root of the corresponding primary tooth due to dislocation by that successor. However, the present survey found that bisphosphonate treatment does not need to be interrupted in such cases when the primary tooth is extracted. Early exfoliation was recognized in not only primary but also permanent teeth in a patient with hypophosphatasia. In another hypophosphatasia patient who received enzyme replacement therapy 1 day after birth, cementum formation was detected. Furthermore, gene therapy was demonstrated to improve dental manifestations in model mice with hypophosphatasia.

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  • Specification of route of Helicobacter pylori infection and construction of preventive approaches for gastric diseases in pediatric dentistry field

    Grant number:15H05049  2015.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    Nakano Kazuhiko, WATANABE Yoshiyuki

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    Grant amount:\17420000 ( Direct expense: \13400000 、 Indirect expense:\4020000 )

    Helicobacter pylori, a Gram-negative microaerophilic bacteria, is known to be a major pathogen related to gastric diseases. The oral cavity is considered to be the source of H. pylori infection, which is mainly acquired in early childhood. In the present study, a novel PCR system for H. pylori detection was constructed using primer sets designed from the complete genome information of 48 H. pylori strains. The bacteria were identified in 38.9% of 131 inflamed pulp specimens obtained from children using the PCR system. In addition, H. pylori strains showed adhesion to human dental fibroblast cells.

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  • Interdisciplinary research for elucidating mechanisms of infective endocarditis onset and development with focus on oral bacteria and host defense interactions

    Grant number:15K11363  2015.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    Nomura Ryota

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    Grant amount:\4810000 ( Direct expense: \3700000 、 Indirect expense:\1110000 )

    To analyze the pathogenesis of IE induced by Streptococcus mutans strains with different patterns of expression of a 120-kDa collagen-binding protein (CBP) and 190-kDa protein antigen (PA), we focused on adhesion of the bacterium to human pulp cells and its interaction with liquid components in blood. CBP-positive S. mutans strains had a high level of adhesion to human pulp cells, while CBP+/PA- strains showed aggregation in the presence of serum, which may contribute to the pathogenicity of IE.

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  • Possible involvement of mutans streptococci in development of pediatric kidney disease

    Grant number:15K15754  2015.04 - 2017.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research  Grant-in-Aid for Challenging Exploratory Research

    Kazuhiko Nakano

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    Grant amount:\3640000 ( Direct expense: \2800000 、 Indirect expense:\840000 )

    We recently reported frequent identification of Streptococcus mutans strains with a collagen-binding protein (Cnm protein) on their cell surface in examinations of specimens obtained from the oral cavity of IgA nephritis (IgAN) patients. In the present study, analyses of detailed clinical findings of patients with IgAN revealed significantly increased dental caries scores and rates of proteinuria detection. In addition, histopathological analyses of kidneys extirpated from rats following inoculation with Cnm-positive S. mutans strains into the oral cavity, which induced severe dental caries, demonstrated IgAN-like findings. Taken together, our results indicate that Cnm-positive S. mutans strains are possibly associated with the pathogenesis of IgAN.

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  • Elucidation of mechanism of non-alcoholic steatohepatitis aggravation caused by mutans streptococci

    Grant number:15K20586  2015.04 - 2017.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)  Grant-in-Aid for Young Scientists (B)

    Naka Shuhei, NAKANO Kazuhiko, NOMURA Ryota

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    Grant amount:\3900000 ( Direct expense: \3000000 、 Indirect expense:\900000 )

    The mechanism of aggravation of non-alcoholic steatohepatitis caused by Streptococcus mutans, a major pathogen of dental caries, was investigated focusing on the cell surface 120-kDa collagen-binding protein (Cnm protein) and 190-kDa Protein Antigen (PA). In hepatic cells with accumulated oleic acid, a type of unsaturated fatty acids, S. mutans demonstrated an ability to attach the hepatic cells via Cnm protein. In addition, bacterial adhesion to unsaturated fatty acids occurred via PA antigen, causing a prominent increase in bacterial adhesion to hepatic cells, thus leading to aggravation of non-alcoholic steatohepatitis.

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  • Establishment of early screening method for gastric diseases caused by Helicobacter pylori

    Grant number:25670872  2013.04 - 2015.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research  Grant-in-Aid for Challenging Exploratory Research

    NAKANO Kazuhiko, OKAWA Rena, NAKA Shuhei

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    Grant amount:\3770000 ( Direct expense: \2900000 、 Indirect expense:\870000 )

    Helicobacter pylori infection is believed to be acquired in early childhood, mainly via the oral cavity. However, the route of infection has yet to be elucidated. In the present study, we constructed a novel PCR system for the identification of H. pylori DNA based on complete genome information of 48 H. pylori strains registered in a database. Analysis of infected root canal specimens using this system revealed a detection rate of 15%, indicating the root canal as a possible reservoir for H. pylori.

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  • Analysis of pathogenic mechanisms related to child obesity associated with oral bacteria

    Grant number:25862010  2013.04 - 2015.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)  Grant-in-Aid for Young Scientists (B)

    NAKA Shuhei

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    Grant amount:\4160000 ( Direct expense: \3200000 、 Indirect expense:\960000 )

    Non-alcoholic steatohepatitis (NASH) occurring in individuals who do not drink alcohol but consume excess calories has recently received attention. In the present study, several oral bacterial strains known to cause periodontitis or dental caries were administered via the jugular vein in NASH model mice in which slight obesity was induced by a high-fat diet. NASH conditions generally develop after 48 weeks in this model. However, elevated levels of cytokines associated with oxidative stress and inflammatory induction were identified within approximately 8 weeks after administration of specific oral bacterial strains. Thus, we speculated that NASH is aggravated following invasion of bloodstream by specific oral strains.

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  • Investigation of mechanism of systemic diseases caused by oral bacteria and development of preventive procedures

    Grant number:23390472  2011.04 - 2014.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    OOSHIMA Takashi, NAKANO Kazuhiko, NOMURA Ryota, NEMOTO Hirotoshi, UMEMURA Kazuo, TANAKA Tokutaro, HOKAMURA Kazuya, NAKA Shuhei, URATA Ayuchi

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    Grant amount:\19240000 ( Direct expense: \14800000 、 Indirect expense:\4440000 )

    Recently, the association of periodontitis with several systemic diseases has received attention. In the present study, the contribution of Streptococcus mutans, a major pathogen of dental caries, to the pathogenesis of infective endocarditis, cerebral hemorrhage, inflammatory bowel disease, and non-alcoholic steatohepatitis was investigated by focusing on cell surface collagen-binding proteins. Our results showed that S. mutans with collagen-binding proteins is possibly virulent for these diseases following invsion of the bloodstream.

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Class subject in charge

  • Development in children and dental disease (2024academic year) 1st semester  - 木1

  • Research Projects: Pediatric Dentistry (2024academic year) special  - その他

  • Lecture and Research Projects: Pediatric Dentistry I (2024academic year) special  - その他

  • Prevention and restoration of dental disease (2024academic year) 1st semester  - 木2

  • Practice with Phantom use in Pediatric Dentistry (2024academic year) Second semester  - 木4~8

  • Practica A for Clinical Specialties in Dentistry(Clinical Pediatric Dentistry) (2024academic year) special  - その他

  • Development in children and dental disease (2023academic year) 1st semester  - 木1

  • Prevention and restoration of dental disease (2023academic year) 1st semester  - 木2

  • Practice with Phantom use in Pediatric Dentistry (2023academic year) Second semester  - 木4~8

  • Dental Health (2023academic year) 1st and 2nd semester  - 金7~8

  • 小児と障害児の歯科治療 (2022academic year) 第4学期

  • Development in children and dental disease (2022academic year) 1st semester  - 木1

  • Prevention and restoration of dental disease (2022academic year) 1st semester  - 木2

  • Practice with Phantom use in Pediatric Dentistry (2022academic year) Second semester  - 木4~8

  • 歯・顎口腔領域の発育異常 (2022academic year) 第4学期

  • Odontology (2022academic year) 1st semester  - 金7・8

  • New development of gene engineering (2022academic year) Third semester  - 木3〜4

  • Development in children and dental disease (2021academic year) 1st semester  - 木1

  • Prevention and restoration of dental disease (2021academic year) 1st semester  - 木2

  • Practice with Phantom use in Pediatric Dentistry (2021academic year) Second semester  - 木4~8

  • Development in children and dental disease (2020academic year) 1st semester  - 木1

  • Prevention and restoration of dental disease (2020academic year) 1st semester  - 木2

  • Practice with Phantom use in Pediatric Dentistry (2020academic year) Second semester  - 木4~8

  • Development in children and dental disease (2019academic year) 1st semester  - 木1

  • Prevention and restoration of dental disease (2019academic year) 1st semester  - 木2

  • Practice with Phantom use in Pediatric Dentistry (2019academic year) Second semester  - 木4~8

  • Development in children and dental disease (2018academic year) 1st semester  - 木1

  • Prevention and restoration of dental disease (2018academic year) 1st semester  - 木2

  • Practice with Phantom use in Pediatric Dentistry (2018academic year) Second semester  - 木4~8

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  • 既製乳歯冠が使えると臨床がラクになる Internet

    1D 株式会社  2024.12

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  • Pathogenic role of dental caries-causing bacteria in IgA nephropathy Internet

    EurekAlert!  2024.11

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  • むし歯菌の表面タンパクが指定難病・IgA腎症発症に関与する可能性が明らかに!〜医科歯科連携で根本治療法の確立を目指す〜 Internet

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  • 意外とムズい、乳歯抜歯

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