Biomedical subjects

Nobuhiro Hanada

Publications and source records attributed to Nobuhiro Hanada.

At least 19 recordsLinked to original sources

PubMed2006

Relationship of cariogenic bacteria levels with periodontal status and root surface caries in elderly Japanese.

OBJECTIVE: The relationship of the levels of cariogenic bacterial species with periodontal status and decayed root surfaces was investigated in elderly Japanese subjects. METHODS: Three hundred and sixty-eight individuals (each 75 years old) were examined for periodontal status (pocket depth, attachment loss), root surface caries and salivary levels of mutans streptococci (MS) and lactobacilli (LB). RESULTS: Values >4 mm of attachment loss (rAL4) and for average attachment loss (aAL) of sites measured were significantly higher in subjects with LB than those without. Multiple regression analysis also showed a correlation between aAL and rAL4 values with the presence of LB (aAL p = 0.003; rAL4 p = 0.002). Further, multiple regression analysis of interacting factors regarding decayed root surfaces showed that LB carriers had a greater incidence of decayed root surface caries (p = 0.003), while MS and LB levels were correlated to the number of decayed root surfaces (LB p = 0.010; MS p = 0.026). CONCLUSION: Our results indicate that considerable attachment loss elevates the possibility of having LB, thus increasing the risk of root surface caries. It was also found that LB and MS measurements may be useful indicators of decayed root surfaces in elderly individuals with attachment loss.

Aged↗

PubMed2006

Assessment of genes associated with Streptococcus mutans biofilm morphology.

Streptococcus mutans, the major pathogen responsible for dental caries in humans, is a biofilm-forming bacterium. In the present study, 17 different pulsed-field gel electrophoresis patterns of genomic DNA were identified in S. mutans organisms isolated clinically from whole saliva. The S. mutans isolates showed different abilities to form biofilms on polystyrene surfaces in semidefined minimal medium cultures. Following cultivation in a flow cell system in tryptic soy broth with 0.25% sucrose and staining using a BacLight LIVE/DEAD system, two strains, designated FSC-3 and FSC-4, showed the greatest and least, respectively, levels of biofilm formation when examined with confocal laser scanning microscopy. Further, image analyses of spatial distribution and architecture were performed to quantify the merged green (live cells) and red (dead cells) light. The light intensity of the FSC-3 biofilm was greater than that of the FSC-4 biofilm in the bottom area but not in the top area. S. mutans whole-genome array results showed that approximately 3.8% of the genes were differentially expressed in the two strains, of which approximately 2.2%, including bacitracin transport ATP-binding protein gene glrA and a BLpL-like putative immunity protein gene, were activated in FSC-3. In addition, about 1.6% of the genes, including those associated with phosphotransferase system genes, were repressed. Analyses of the glrA-deficient strains and reverse transcription-PCR confirmed the role of the gene in biofilm formation. Differential assessment of biofilm-associated genes in clinical strains may provide useful information for understanding the morphological development of streptococcal biofilm, as well as for colonization of S. mutans.

Adult↗

PubMed2006

Influence of a fluoride mouthrinse on mutans streptococci in schoolchildren.

This study aimed to determine whether the long-term use of a fluoride mouthrinse affects the salivary levels of mutans streptococci. Two hundred and fifteen schoolchildren (aged 9-10 years) participated. One hundred and forty-nine of these children had used a fluoride mouthrinse since 5 years of age at nursery school, and the remaining 66 children had not. DFT (decayed and filled teeth) was recorded, and the salivary levels of Streptococcus mutans and Streptococcus sobrinus were measured using mitis salivarius bacitracin agar. The group that had used a fluoride mouthrinse had a significantly lower prevalence of both S. mutans and S. sobrinus (p = 0.038) and a significantly lower DFT score (p < 0.001) than the other group. Using logistic regression analysis including caries experience at baseline as a dependent variable, the odds ratio of carrying S. mutans alone was 8.0 (p = 0.066) and that of carrying both S. mutans and S. sobrinus was 16.5 (p = 0.022) in the group that had not used the fluoride mouthrinse. Children carrying both S. mutans and S. sobrinus had a higher caries incidence in 1 year than the others, with odds ratios of 5.73 (p = 0.067) in the group with a fluoride mouthrinse and 3.47 (p = 0.035) in the group without it. These results show that the long-term use of a fluoride mouthrinse is associated with reduced salivary levels of mutans streptococci and this bacterial reduction may partly contribute to the suppression of dental caries in children using a long-term fluoride mouthrinse.

Cariostatic Agents↗

PubMed2006

Production of Fab fragment corresponding to surface protein antigen of Streptococcus mutans serotype c-derived peptide by Escherichia coli and cultured tobacco cells.

The cDNA of a mouse Fab fragment was cloned from a hybridoma cell line that produces a mouse monoclonal antibody, KH5, that reacts with the peptide fragment of the surface protein antigen of Streptococcus mutans serotype c (PAc). After transfection with cDNA, recombinant Fab fragments were produced by Escherichia coli (T15 Fab) and cultured tobacco cells (X253 and X262 Fabs). The antipeptide activities of T15 and X253 were similar to that of KH5. X253 was secreted into the culture media, which had a specific affinity for the PAc peptide.

Amino Acid Sequence↗

PubMed2006

Oral health status and health-related quality of life: a systematic review.

This study was conducted in order to identify the literature on oral health status and health-related QOL, review the findings systematically, and assess the association between them. We performed a literature search of reports published between January 1973 and June 2004, using five databases including MEDLINE. Only studies that used validated generic health-related QOL instruments were selected. The reviewers evaluated selected articles independently and resolved disagreements by consensus. A total of 1,726 articles were retrieved and seven were selected for the review; five observational studies and two intervention studies. Four studies showed significant associations between oral health status and health-related QOL. Temporomandibular disorders were highly associated with reduced health-related QOL. Poor oral status linked to both craniomandibular and cervical spinal pain was associated with increased impairment of health-related QOL. Dissatisfaction with the teeth and mouth, and a sensation of dry mouth contributed to reduce health-related QOL. Providing edentulous patients with implant-supported full dentures contributed to improve health-related QOL. Assessment of health-related QOL in relation to oral health with validated instruments remains insufficient. The present findings suggest that oral health status could affect health-related QOL in some settings; however, further evidence is needed to support this interpretation.

Craniomandibular Disorders↗

PubMed2006

Study of the clinical usefulness of a dental drug system for selective reduction of mutans streptococci using a case series.

The aim of this study was to evaluate the clinical efficacy and safety of a dental drug delivery system (3DS) for the selective reduction of mutans streptococci. Twenty patients with high levels of mutans streptococci in saliva participated. The efficacy of 0.2% chlorhexidine (CHX) delivered by 3DS in reducing the salivary levels of mutans streptococci compared with total streptococci and lactobacilli was investigated. Each subject was treated by professional mechanical tooth cleaning (PMTC) and subsequently individual trays with CHX for 5 min. Salivary bacterial samples were taken at the baseline and weeks 1-12. A significant reduction in the colony count of mutans streptococci was observed during the first 4 weeks compared with the baseline count, while no significant decrease in the count of total streptococci or lactobacilli was found during 12 weeks. In particular, the proportion of mutans streptococci in total streptococci remained low after 12 weeks. Our results indicate that the new 3DS used in combination with PMTC appears to be a promising intraoral drug delivery system which, when used with a low CHX concentration selectively, effectively reduces mutans streptococci in the oral cavity with no adverse effects.

Adult↗

PubMed2006

Screening of periodontitis with salivary enzyme tests.

The purpose of this study was to determine the usefulness of salivary biochemical markers for the screening of periodontal disease and examine the agreement between the results of saliva enzyme tests and those of probing depth. The present study included a total of 187 subjects who underwent annual medical check-ups at the Comprehensive Health Care Center, Honjo, Saitama Prefecture, Japan. Periodontal pocket probing was performed with a WHO probe, and various enzymes and biochemical parameters in saliva were measured. For lactate dehydrogenase (LDH), the proportions of the five isoenzymes were calculated. To decide the cut-off point for each enzymatic activity, receiver operating characteristic curves (ROC curves) were constructed and the points of minimum difference between sensitivity and specificity were decided. Among the biochemical markers tested, salivary LDH level had the highest sensitivity and specificity (sensitivity 0.66, specificity 0.67), while salivary levels of aspartate aminotransferase (AST) and blood urea nitrogen (BUN) also had sensitivity and specificity above 0.60. Among the LDH isoenzymes, LDH4 and LDH5 dominated in whole saliva samples. Salivary LDH may be a feasible and useful parameter for the screening of periodontal disease, while salivary AST and BUN also appear to be potentially useful for this purpose.

Adult↗

PubMed2006

Correlation of cariogenic bacteria and dental caries in adults.

Many studies suggest that mutans streptococci (MS), Lactobacillus (LB), and salivary buffering capacity are important risk factors for dental caries. However, target populations for most studies were children. In adult patients, the same risk factors affect the number of fillings or prostheses or secondary caries. It is therefore important to investigate these risk factors as predictors of caries in adults. In the present study, we evaluated the oral conditions of adult subjects at private dental offices using bite-wing radiographs. Detection of salivary LB level using Dentocult LB had a statistically significant correlation with the number of flat surface caries and approximal caries (P < 0.001). Detection of salivary MS level using Dentocult MS and salivary buffering capacity did not predict dental caries. Thus, detection of salivary LB level using Dentocult LB may be a useful tool for detecting approximal and secondary caries.

Adult↗

PubMed2005

An ingenious design for peptide vaccines.

For humoral immunization, it may be possible to make effective and safe peptide vaccines for various diseases by selection of proper B-cell epitopes. However, a lack of T-cell epitopes on short peptides, such as those associated with major histocompatibility complex (MHC)-restriction, is a major problem for peptide vaccine development. We propose a solution for the design of peptide vaccines that involves induction of broadly reactive T-cell epitopes via agretopes. The strategy involves positioning multi-agretope type peptides on the N-terminal side of a di-lysine linker and B-cell epitopes on the C-terminal side. The addition of the arginine-glysine-aspartate (RGD)-motif to the N terminus of the peptide enhances its immunogenicity, and enables nasal immunization without adjuvants.

Amino Acid Sequence↗

PubMed2005

The relationship between dietary intake and the number of teeth in elderly Japanese subjects.

OBJECTIVE: This study used a precise weighing method to assess whether tooth loss was related to nutrient intake in elderly Japanese subjects. MATERIAL AND METHODS: Fifty-seven subjects aged 74 years were randomly selected from a longitudinal interdisciplinary study of ageing. Complete 3-day food intake data were obtained by a precise weighing method. The dietary intakes of energy and nutrients were calculated based on the Standard Tables of Food Composition in Japan (5th ed.). A clinical evaluation of the number of teeth present was carried out. Multiple regression standardised coefficients for each nutrient was estimated based on a continuous scale adjusted for gender, smoking habits, and educational level. After dividing the subjects into two groups according to the number of teeth present (0-19, 20+), the difference in the intake of nutrients and the amount of food consumed per day was evaluated. RESULTS: The number of teeth present had a significant relationship with the intake of several nutrients. In particular, total protein, animal protein, sodium, vitamin D, vitamin B1, vitamin B6, niacin, and pantothenic acid were significantly associated with the number of teeth present and with the two groups (0-19, 20+). The intake of vegetables and fish, shellfish, and their products was significantly lower among subjects with fewer teeth. CONCLUSION: This study suggests that there was a significant relationship between nutrient intake, such as minerals and vitamins from food, and tooth loss.

Aged↗

PubMed2005

Correlation between patient satisfaction and dental clinic credibility in regular dental check-ups in Japan.

The aim of this study was to investigate the relationship between dental clinic credibility and patient satisfaction with regular dental check-ups, to compare the level of satisfaction of patients who had regular check-ups with those who did not, and to identify factors associated with regular dental checkups. Thirty-nine private dental clinics in 17 prefectures throughout Japan participated in this study. A total of 9024 questionnaires were distributed to the patients at these clinics, and patients returned the questionnaires using a pre-paid envelope (response rate 56.8%). The questionnaires consisted of items related to patient demographics and 11 items concerning the level of patient satisfaction with the dental clinic. Using multiple logistic regression analysis, the strongest correlation was found between dental clinic credibility in regular checkups and the technical competence of the dentist. The responses to those items concerning making an appointment, and the cleanliness and neatness of the waiting room were different between patients who had regular check-ups and those who did not. To investigate the factors that encourage regular dental check-ups, correlation of factors with regular check up experience were analyzed. Multivariate-adjusted odds ratios indicated a strong association between regular dental check ups and both the technical competence of the dental hygienist and the cost of treatment.

Adult↗

PubMed2004

E2f1 mutation induces early onset of diabetes and Sjögren's syndrome in nonobese diabetic mice.

E2f1 is an important regulator of T cell proliferation, differentiation, and apoptosis that controls the transcription of a group of genes that are normally regulated at the G1 to S phase transition in the cell cycle. Insulin-dependent diabetes mellitus (IDDM) and Sjogren's syndrome (SS) are highly regulated autoimmune diseases that develop spontaneously in NOD mice. The aim of the present in vivo study was to explore the functional importance of the E2f1 molecule in IDDM and SS, in the context of whole animal physiology and pathophysiology, using E2f1-deficient NOD mice. For the experiment, we produced NOD mice homozygous for a nonfunctional E2f1 allele onto a NOD background. E2f1-deficient NOD mice developed an early and increased onset of diabetes as compared with their littermates. These mice also exhibited a defect in T lymphocyte development, leading to excessive numbers of mature T cells (CD4+ and CD8+), due to a maturation stage-specific defect in the apoptosis of thymocytes and peripheral T cells. We also found that they also exhibited a more rapid and increased entry into the S phase following antigenic stimulation of spleen cells and thymocytes in vitro. Furthermore, E2f1-deficient mice showed a profound decrease of immunoregulatory CD4+CD25+ T cells, while the spleen cells of NOD mice lacking E2f1 showed a significant increase of the proinflammatory cytokine IFN-gamma following antigenic stimulation in vitro. Consistent with these observations, E2f1 homozygous mutant NOD mice were highly predisposed to the development of IDDM and SS.

Animals↗

PubMed2004

Oral streptococci exhibit diverse susceptibility to human beta-defensin-2: antimicrobial effects of hBD-2 on oral streptococci.

We examined the antimicrobial effects of human beta-defensin-2 (hBD-2) on 17 species of oral streptococci to investigate the involvement of antimicrobial peptide activity in oral microflora development and the clinical use of the antimicrobial peptide for oral microflora control. Oral streptococci exhibit diverse levels of susceptibility to human beta-defensin-2 (hBD-2). Two major cariogenic bacterial species, Streptococcus mutans ( S. mutans) and S. sobrinus, were found to be susceptible to the peptide, indicating that it is a potential therapeutic agent for preventing dental caries. S. mitis exhibited the lowest susceptibility to the peptide. S. mitis is a major indigenous bacterium in the oral microflora, and our results suggest that it might possess a certain resistance mechanism against hBD-2.

Anti-Infective Agents↗

PubMed2004

Sexual differences in oral health behaviour and factors associated with oral health behaviour in Japanese young adults.

The aim of this study is to compare the state of oral health behaviour between genders and to analyse factors associated with oral health behaviour by gender in young adults. Anonymous questionnaire data were collected from 527 adults (245 men and 282 women) aged 20-29 years who consulted dentists in Chiba City. The Chi-square test, Mann-Whitney analysis, and logistic regression analysis were used to examine the differences in oral health behaviour and determinants of oral health behaviour between young men and young women. The rate of good behaviour among women were significantly higher than those among men in each oral health behaviour item (toothbrushing frequency p < 0.001; using dental floss p = 0.042; dental check-ups p < 0.001). In women, factors associated with each oral health behaviour were as follows: toothbrushing frequency (family composition p = 0.030); using dental floss (dental health knowledge p = 0.025, employment status p = 0.031), and dental check-ups (age group p = 0.024). In men, a significant relationship was seen only between using dental floss and age group p = 0.025). This study indicated that young women had better oral health behaviour and that more factors were associated with their oral health behaviour in comparison with young men.

Adult↗

PubMed2004

Relationship between oral motor dysfunction and oral bacteria in bedridden elderly.

OBJECTIVE: The purpose of this study was to analyze the relationship between oral bacterial colonization and oral motor dysfunction. STUDY DESIGN: Oral motor dysfunction (swallowing and speech disorders) and detection of oral bacterial species from dental plaque in 55 elderly persons who had remained hospitalized for more than 3 months were investigated and statistically analyzed. RESULTS: The detection rates of methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Streptococcus agalactiae, and Stenotrophomonas maltophilia were significantly higher in subjects with than in those without a swallowing disorder. A similar result was found with regard to the presence of a speech disorder. About half of subjects who had oral motor dysfunction and hypoalbuminemia had colonization by MRSA and/or Pseudomonas aeruginosa. CONCLUSION: These results suggest that the combination of oral motor dysfunction and hypoalbminemia elevated the risk of opportunistic microorganisms colonization in the oral cavity of elderly patients hospitalized over the long term.

Aged↗

PubMed2004

A longitudinal study of the relationship between periodontal disease and bone mineral density in community-dwelling older adults.

OBJECTIVE: Bone loss is a common feature of periodontitis and osteoporosis. Both diseases may share common etiologic agents which may either affect or modulate the process of both diseases. The purpose of this study was to evaluate the relationship between systemic bone mineral density (BMD) and periodontal disease among older people. MATERIALS AND METHODS: Among all 4,542 inhabitants aged 70 years according to a registry of residents in Niigata city in Japan, 600 people were selected randomly. One hundred and eighty-four subjects who did not have diabetes mellitus, whose blood sugar was <140 mg/dl, who had more than 20 teeth, who were non-smokers, and who did not take medication for osteoporosis, were included in the study. Four dentists performed clinical evaluations on probing attachment level (PAL). We also utilized the data on BMD of the heel, which we measured using an ultrasound bone densitometer. Follow-up clinical surveys were done by measuring PAL after 3 years. Finally, 179 subjects who could participate in both the baseline and the follow-up examinations were included in the analysis. After dividing the subjects into an osteopenia group (OG) and non-osteopenia group (NOG), we evaluated the relationship between BMD and the number of progressive sites which had > or =3 mm additional attachment loss during 3 years after controlling the known confounding factors. RESULTS: The mean number of progressive sites for the OG and the NOG, respectively, were 4.65+/-5.51 and 3.26+/-3.01 in females and 6.88+/-9.41 and 3.41+/-2.79 in males. Two-way analysis of variance was performed to discriminate among effects of gender, BMD, and gender-BMD interaction. A significant effect of BMD (OG or NOG, p=0.043) with a significant interaction (p=0.038) was observed. Furthermore, BMD was associated with the number of progressive sites which had > or =3 mm additional attachment loss during the 3 years (p=0.001) by multiple linear regression analysis. CONCLUSIONS: This study suggested that there was a significant relationship between periodontal disease and general BMD.

Age Factors↗

PubMed2004

Growth-inhibitory effect of antibacterial self-etching primer on mutans streptococci obtained from arrested carious lesions.

BACKGROUND: An antibacterial self-etching primer has been developed to inhibit bacterial attachment and plaque accumulation on the tooth surfaces. The purpose of this study was to evaluate the growth-inhibitory effect of an antibacterial self-etching primer on mutans streptococci obtained from arrested carious lesions. MATERIALS AND METHODS: Softened dentin specimens were obtained from arrested carious lesions with an excavator or a round steel bur. The effect of a commercial antibacterial self-etching primer and a commercial self-etching primer on the total streptococci on Mitis-Salivarius (MS) agar plates and on Streptococcus mutans on MS agar plates containing 0.02 M bacitracin (MSB) was evaluated. Specimens with no primer were used as controls. The number of colonies of both total streptococci and S. mutans were compared statistically with two-way analysis of variance and Fisher's Protected Least Squares Differences (PLSD) test (p < .05). RESULTS: The number of colonies of total streptococci (CFU/mL) for the two methods (excavator and round steel bur) were as follows: for the control, 5.0 x 10(6) and 5.0 x 10(6); for the self-etching primer, 1.0 x 10(5) and 1.0 x 10(5); and for the antibacterial self-etching primer, 0 and 0. The number of colonies of S. mutans for the two methods (excavator and round steel bur) were as follows: for the control, 5.0 x 10(6) and 1.8 x 10(5); for the self-etching primer, 3.5 x 10(4) and 5.0 x 10(3); and for the antibacterial self-etching primer, 0 and 0. Regardless of the method of softened dentin removal, the antibacterial effect was significantly higher for the group that had antibacterial self-etching primer compared with that of the control group and the group that had commercial self-etching primer (p < .05). CLINICAL SIGNIFICANCE: The antibacterial self-etching primer showed a high level of antibacterial activity against mutans streptococci obtained from the arrested carious lesions.

Adult↗

PubMed2004

Relationship between volatile sulphide compounds concentration and oral bacteria species detection in the elderly.

AIM: To evaluate the relationship between oral bacteria species detection and volatile sulphide compounds (VSC) concentration in the elderly. DESIGN: Cross-sectional microbiological and clinical VSC examination of elderly. PARTICIPANTS: Sixty-seven elderly people aged 75, who were functionally independent and dentate. METHODS: VSC (H2S and CH3SH) concentrations in the mouth air of subjects were measured using portable gas chromatography. Oral bacteria samples were taken from dental plaque and identification of bacteria species was accomplished using standard methods. RESULTS: Fewer than 20% of subjects showed more than 10 ng/10 ml of H2S (severe odour level). The detection rate of P. melaninogenica was significantly higher in elderly people with more than 10 ng/10 ml (p=0.043) levels. Fusobacterium had a tendency to be found in those with more than 10 ng/10 ml, but a significant relation was not found. CONCLUSIONS: The results suggest that Fusobacterium and P. melaninogenica may be involved in the production of H2S in the oral cavity of elderly people.

Aged↗