Faculty Profiles - NAKA Shuuhei

Papers - NAKA Shuuhei

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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

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

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.

DOI： 10.1016/j.archoralbio.2013.06.008

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

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

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.

DOI： 10.1016/j.archoralbio.2013.02.007

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

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

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.

DOI： 10.1111/odi.12016

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

Language：English Publisher：The Japanese Society of Pediatric Dentistry

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

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

Language：English Publisher：The Japanese Society of Pediatric Dentistry

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

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

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

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

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

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

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

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

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

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

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

Language：English Publisher：The Japanese Society of Pediatric Dentistry

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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