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Biomedical subjects

T Matsukubo

Publications and source records attributed to T Matsukubo.

At least 19 recordsLinked to original sources
PubMed2006

Statherin and histatin 1 reduce parotid saliva-promoted Streptococcus mutans strain MT8148 adhesion to hydroxyapatite surfaces.

Small salivary phosphoproteins--statherin (ST) and histatin 1 (HT1) - are found in the acquired enamel pellicle which modulates Streptococcus mutans adhesion onto dental enamel. However, their roles in S. mutans adhesion onto enamel surfaces are still undefined. The aim of this study was to investigate whether and how ST and HT1 affect (i) S. mutans adhesion and (ii) the adsorption of S. mutans adhesion-promoting salivary proteins onto hydroxyapatite (HA) in vitro. We fractionated human parotid saliva by adsorption to HA and further by gel filtration chromatography. Adhesion of [3H]-labeled S. mutans strain MT8148 onto sintered HA plates was promoted significantly (>10-fold) by high-molecular weight glycoprotein fraction (HMWGP), but not by purified ST or HT1. More interestingly, promotion of S. mutans adhesion onto HA by HMWGP was significantly reduced by adding purified ST or HT1 to HMWGP. [3H]-labeled S. mutans adhesion on HA was positively correlated to the [14C]-labeled HMWGP adsorption onto HA, which was also reduced by the addition of purified ST and HT1. Synthetic peptides corresponding to ST and HT1 reduced the parotid saliva-promoted S. mutans adhesion. However, removal of the negative charges in the N-terminal domains of ST and HT1 diminished their inhibitory effects on S. mutans adhesion promoted by parotid saliva. We conclude that ST and HT1 competitively inhibit the adsorption of salivary HMWGP, and thereby reduce S. mutans adhesion onto HA surfaces.

Adsorption↗
PubMed2004

Salivary flow and its relationship to oral signs and symptoms in patients with dry eyes.

OBJECTIVES: The aim of this study was to investigate oral symptoms and clinical parameters in dry eye patients. Subjective reports of the sensation of a dry mouth, salivary flow rates, and clinical parameters of oral disease related to three different types of dry eye patients were examined. SUBJECTS AND METHODS: There were 224 individuals, including dry eye patients and control subjects. The dry eye patients were classified into three types: patients with Sjögren's syndrome (SS-DE), patients without SS-DE (non-SS-DE), and patients with Stevens-Johnson syndrome (SJS-DE). Salivary flow rates were measured using two kinds of sialometry. Subjective and objective oral symptoms and signs were also examined. RESULTS AND CONCLUSION: Over half of the dry eye patients complained of a dry mouth. The flow rates of their stimulated whole saliva and parotid saliva were significantly lower than those of the control groups (P < 0.05, P < 0.01). The sensation of a dry mouth and changes in oral soft tissues, dental caries, and oral Candida frequently occurred in dry eye patients.

Adult↗
PubMed2001

Comparison of the activity of four chitosan derivatives in reducing initial adherence of oral bacteria onto tooth surfaces.

We examined the effects of four kinds of chitosan derivatives on initial adherence of oral bacteria onto human anterior teeth surfaces. The buccal surfaces of anterior teeth were used as the experimental surfaces. They were divided into five rectangle areas with outer dimensions of about 2 mm x 4 mm. After applying two ml of a sample solution onto the tooth surfaces, an examiner wiped each rectangle area with a sterilized plastic swab one, three and six hours later. Then we measured bacterial counts in sterilized swabs with mitis salivarius agar. We found that the order of magnitude of the inhibitory effect on the adherence of oral bacteria was low molecular chitosan > phosphorylated chitosan > amorphous chitosan > carboxymethyl chitosan. The solution containing 0.5% low molecular chitosan depressed the bacterial adherence to the same extent as a 50 ppm chlorhexidine digluconate solution for three hours, and 0.1% phosphorylated chitosan also exhibited an inhibitory effect in bacterial adherence for one hour. Amorphous chitosan had a moderate inhibitory effect, but no clear inhibitory activity was found with 0.1% carboxymethyl chitosan. These results suggest that low molecular chitosan and phosphorylated chitosan have the potential to effectively inhibit the initial adherence of oral bacteria onto human tooth surfaces.

Adult↗
PubMed2001

Effect of rinsing with phosphorylated chitosan on four-day plaque regrowth.

This clinical investigation examined the effect of phosphorylated chitosan rinsing on plaque development and on the buffering capacity of plaque suspension. Three male adult subjects participated in the trial that was designed as a single blind study. Participants refrained from mechanical oral hygiene procedures during a four-day study and rinsed three times a day with 20 ml of test solutions. A wash-out period of three days was instituted between the placebo and phosphorylated chitosan rinsing period. Clinical evaluation and plaque sampling were performed at the end of each test period. We disclosed plaque accumulations on the buccal upper front teeth with a two-tone disclosing agent to distinguish between newly formed plaque and old plaque. After taking color slides, we then used a computerized image analysis. Tooth areas covered by plaque on the color slides were digitized and expressed as percentages of the tooth area. The buffering capacity of the collected plaque fluid was determined by using a beta-titrator. A mouth rinse containing 0.5% phosphorylated chitosan significantly reduced both newly formed plaque areas (red disclosed; p < 0.001) and old plaque areas (blue disclosed; p < 0.01) compared to a placebo rinsing. However there was no significant difference in the plaque buffering capacity (p > 0.05) between the mouth rinse containing 0.5% phosphorylated chitosan and placebo. These findings might suggest that mouth rinse containing phosphorylated chitosan would be effective in reducing plaque formation and have a slight ability to enhance plaque buffering capacity.

Adult↗
PubMed1997

Caries-inducing activity of the hydrogenated derivative of an isomaltooligosaccharide mixture in rats.

The caries-inducing activity of the hydrogenated derivative of an isomaltooligosaccharide mixture (IMO-H) was evaluated in vitro for its acidogenicity and in vivo an experimental caries system with specific-pathogen-free (SPF) rats. Streptococcus sobrinus 6715 (serotype g) did not produce a significant amount of acid from IMO-H, whereas Streptococcus mutans MT8148 (serotype c) gradually produced a small amount of acid, although the degree was less than that of sucrose. In vivo experiments were conducted on rats which were provided with the test sugars at two different times: at the time of organism inoculation, and after the organisms had become completely established. IMO-H did not induce significant dental caries in rats infected with the S. sobrinus 6715 or S. mutans MT8148R strain.

Acids↗
PubMed1997

Effects of a hydrogenated isomaltooligosaccharide mixture on glucan synthesis and on caries development in rats.

The caries inhibitory effect of the hydrogenated derivative of an isomaltooligosaccharides mixture (IMO-H) was examined in vitro and in vivo experiments. IMO-H could not be used as a substrate for the crude glucosyltransferases (GTases) of Streptococcus sobrinus 6715 to synthesize water-insoluble glucan. Moreover, it not only significantly inhibited the synthesis of water-insoluble glucan from sucrose, but also the sucrose-dependent adherence of these growing cells the glass surfaces. In the in vivo experiment, the addition of IMO-H to a sucrose-containing diet resulted in significant reduction of caries development in specific-pathogen-free (SPF) rats infected with S. sobrinus 6715.

Animals↗
PubMed1995

Evaluation of acidogenicity of commercial isomaltooligosaccharides mixture and its hydrogenated derivative by measurement of pH response under human dental plaque.

The acidogenicity of commercially available isomaltooligosaccharides mixture (IMO) and its hydrogenated derivative (IMO-H) were evaluated by the in vivo pH response under dental plaque of six subjects (aged 25-28) using intraoral apparatus. The apparatus, an indwelling pH sensor of a hydrogen ion-sensitive field effect transducer (ISFET), was placed on the buccal site of the mandibular first molar, and the plaque was accumulated for four days. The test sugars were applied with three methods-dropping the solution directly on the plaque, rinsing the oral cavity with the solution, and sucking a candy made of the test sugar (weight 3-4 g). IMO could not be evaluated as a type of sugar with low acidogenicity, especially by the candy method, but IMO-H could be evaluated as a type of sugar with very low acidogenicity in a similar manner as maltitol or sorbitol in all type of applications. The acidogenic response of dental plaque should be assumed to be closely related to salivary parameters such as the secretion rate or to mutans streptococci level of subjects and types of application.

Adult↗
PubMed1994

The influences of the buffer capacity of various substances on pH changes in dental plaque.

This study clarified the suitable pKa value for buffering substances against plaque pH fall in vitro and simultaneously estimated the effect of low molecular chitosan (LMCS) on plaque pH lowered by metabolized acids in vitro and in vivo. Five buffering substances with different pKa, aspartame (pKa: 7.8), phosphate buffer (7.1), LMCS (6.4), maleate buffer (6.2), and monofluorophosphate (4.8), were tested in this study. In the method using S. mutans cells, phosphate inhibited the pH fall from an initial pH of over 7.0, but phosphate exhibited no effect when the initial pH was 6.0. By the addition with lactic acid, LMCS and maleate exhibited more effective inhibition of the pH-fall than the others. These observations imply that pKa value is an important indicator of the ability of a buffering substance to reduce pH fall in dental plaque and that the optimum pKa value may be around pH 6.3. In the plaque pH measurement using ISFET electrode, LMCS showed an additional effect in inhibiting plaque pH fall following direct application of the glucose solution. The findings indicate that LMCS may be useful as a food additive to decrease the cariogenicity of foods.

Adult↗
PubMed1994

Effects of low molecular chitosan on pH changes in human dental plaque.

Effects of six kinds of low molecular chitosan (LMCS) on pH changes in dental plaque were compared in vitro and in vivo in order to clarify the relationship between their characteristics and effectiveness. Six LMCS with different molecular weights (MW) (500-3,000) and degrees of deacetylation (DAC) (50-95%) were prepared for this study. Evaluations using S. mutans cell suspensions in vitro showed that all samples had almost equal abilities to reduce pH fall in dental plaque. They were found to have no influence on the glycolytic activity of S. mutans. However, clinical evaluations of pH fall in dental plaque using an ion-sensitive field-effect transistor (ISFET) electrode showed unexpected results as follows; The most reduction in pH fall was obtained with the LMCS with a MW of 3,000 and a DAC of 50%, which had been presumed to be the most ineffective sample. The second ranked LMCS in this experiment had a MW of 500 and a DAC of 95%; it had been expected to be the most effective one. The findings indicated that LMCS has a high ability to inhibit pH fall in dental plaque and suggested that such properties as molecular weight and degree of deacetylation can have great influences upon its activity in clinical application.

Acetylation↗
PubMed1994

pH response of human dental plaque to chewing gum supplemented with low molecular chitosan.

The effects of low molecular chitosan (LMCS) on pH responses of human dental plaque following exposure to fermentable carbohydrates were investigated by an ion-sensitive field-effect transistor electrode system. After the plaque pH values were minimized by direct application of 5% glucose solution or consumption of sugared caramel, the subjects started chewing the test gums containing 0 (control), 1 or 3% (w/w) LMCS for three minutes. The pH response was monitored until it recovered to over pH5.5. In the case of the glucose solution, chewing 3% LMCS gum caused significantly more rapid pH recovery toward the resting level than did the control gum. Initial pH rising rate during gum chewing was faster with either of the two LMCS gums than with the control gum. In the case of caramel, additional effects of LMCS were observed numerically as LMCS content increased. The findings indicated that LMCS had a potential to promote recovery of plaque pH after acidogenic challenge and to maintain the plaque pH around neutrality.

Adult↗
PubMed1992

Decline in caries prevalence in 6-14-year-old schoolchildren during 1975-85 in Shizuoka, Japan.

The purpose of this study was to examine changes in caries prevalence during 1975-85 in Japanese schoolchildren who did not have an apparent change in fluoride exposure. A total of 2872 schoolchildren aged 6-14 yr in two primary schools and one junior high school in Shizuoka city, Japan, were examined in 1985. The caries prevalence in 1985 was then compared with data which had been collected in a longitudinal survey on schoolchildren in the same primary and junior high schools by Katayama in 1970-75. The results indicated that DMFT and DMFS indices in 1985 were significantly lower than those in 1970-75 in all the examined ages (P < 0.01). The DMFT indices at age 12 were 3.60 in 1985 and 5.47 in 1970-75. Remarkable decreases in DMFT at age 12 were observed in maxillary incisors (50%), followed by maxillary molars (24%) and mandibular molars (22%). The decline in caries prevalence in the examined area may be mainly attributed to several factors other than use of fluoride, such as changes in dietary pattern, an increasing dental awareness and promotion of dental health care. But the percentage decrease per annum of DMFT index at age of 12 in the examined population was relatively low (-4.1%) in comparison with other industrial countries. Comparing the results with data from national dental surveys, it can be considered that rural areas in Japan do not exhibit a similar decline of caries prevalence as in Shizuoka city, but there will be a lot of districts exhibiting significant reduction in caries prevalence in the near future.

Adolescent↗
PubMed1991

Inhibition of adsorption of oral streptococci to saliva treated hydroxyapatite by chitin derivatives.

This study estimated the effects of five chitin derivatives low molecular chitosan (LMCS), ethyleneglycol chitin (PEGT), carboxymethyl chitin (PCMT), sulphated chitosan (PSSS), and phosphorylated chitin (PPPT) on the adsorption of three oral streptococci to saliva-treated hydroxyapatite (S-HA). The adsorption was evaluated by measuring the optical density of the bacterial cell suspensions released from saliva-treated hydroxyapatite by 0.5 N HCl. The adsorption of test strains to S-HA progressively decreased in proportion to each additional volume of PEGT, PPPT, or PSSS. PPPT and PSSS quite effectively inhibited the adsorption of S. mutans onto S-HA, but were less effective against S. sanguis and S. mitis. PPPT, PSSS, and PCMT all markedly promoted the desorption of S. mutans cells pre-adsorbed onto S-HA. Pretreatment of S-HA with PPPT, PSSS, or PCMT significantly decreased the subsequent adsorption of S. mutans and S. mitis. Pretreatment of these cells with PEGT also decreased their adsorption to S-HA. These findings suggest that these chitin derivatives may change the ionic natures of the S-HA and the bacterial cell surface, resulting in a less favorable interaction.

Adult↗
PubMed1990

Epidemiological analysis for the influences of plaque and calculus deposition on prevalence of pocket formation.

The influence of plaque and calculus deposition on the prevalence of pocket formation was studied using cross-sectional data from 615 Japanese manual workers aged 18-49. A periodontal pocket with a depth of 4 mm or more from gingival margin to bottom of the pocket was coded as presence of pockets. The oral hygiene status at the specified site was classified into four hygiene patterns as no deposition, deposition of plaque only, deposition of calculus only and deposition of both plaque and calculus. The percentages of six specified tooth types with pocket formation were analyzed according to the local hygiene condition. The results indicate that local oral hygiene produces significant differences in the proportion of teeth with pocket formation in the examined tooth types. The frequency of site-specific hygiene condition were no deposition, deposition of plaque only and deposition of both plaque and calculus, except for the lower central incisors. The teeth without plaque and calculus show no pocket formation in most of the examined tooth types in the subjects aged 18-39, while teeth with plaque and/or calculus indicate high prevalence of pocket formation. It is also revealed that the teeth with both plaque and calculus tend to show higher percentages of pocket formation than those with plaque only. These findings suggest that promotion of a plaque free state would reduce risk for pocket formation to negligible level, and that calculus deposition increase the risk for pocket formation around the teeth with plaque.

Adult↗
PubMed1989

[Dental health status of junior high school students in the suburbs of Chiba city].

The Population of 12-15 years is a key age group for oral health because the permanent dentition and periodontal tissues are almost complete at this stage. The purpose of this study was to evaluate oral health status and to develop an effective school dental health program for junior high schools students. The survey was performed on 527 persons aged 12-13 at 2 junior high schools in the suburbs of Chiba city. Periodontal disease was evaluated on the basis of the CPITN, and analyzed for severity and region of periodontal disease. Gingivitis was examined with PMA index, using color photo slides taken of anterior dentition at the time of inspection. At the same time, caries experience and oral hygiene index were also estimated. The results were as follows: (1) The mean DMFT was 3.89. Caries prevalence in females was higher than males. Ratio of treated teeth rate was 77.03%; that of untreated teeth rate was 22.65%. Females revealed less treatment for caries than males. Oral hygiene index showed significant difference between males and females. Labial and buccal parts of the maxillary and molar region on the mandibular showed remarkable plaque deposition. Calculus accumulation in this population was greatest on the lower incisor. (2) The mean PMA index was 7.36. Gingivitis was highly prevalent in both sexes, although it was more severe in males. There was correlations between PMA index and OHI. (3) From the results of CPITN, 10.6% of the subjects showed no signs of periodontal disease (Code 0), and 5.7% exhibited gingival bleeding (Code 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Distribution of dental plaque and time analysis of toothbrushing without instruction in school children and students].

The purpose of this study is to evaluate oral hygiene before and after individual method toothbrushing without instruction and to analyze toothbrushing times for school children from 6 to 13 years of age. Subjects were 150 pupils from primary to junior high school affiliated with the faculty of education of an university located in Setagaya, Tokyo: 38 first-grade pupils aged 6, 36 fourth-grade pupils aged 9, 37 sixth-grade pupils aged 11, and 39 second-year junior high school pupils aged 13. Assessments of dental plaque were made by two dentists using the PHP plaque score (Podshadely and Haley, 1968) for primary school pupils and OHI-S (only DI-S; Greene and Vermillion, 1964) for junior high school pupils. Plaque distribution disclosed by an Erythrosine solution was examined before and after toothbrushing, and the performance of toothbrushing by subjects was recorded on video-tape through a one-way mirror so that the children were unaware. Toothbrushing time was measured by 2 or 3 examiners using a time counter of video-monitor. Average scores for dental plaque before and after toothbrushing were almost the same for first and fourth-grade primary school pupils; but scores decreased with a statistically significant difference (p less than 0.01) for sixth-grade pupils. Distribution patterns of plaque scores for fourth-grade pupils showed characteristically narrow ranges (2-5 before brushing and 1-4 after brushing). The majority of subjects (69.4%) had scores of 2-3 after brushing, Whereas only 8.3% showed a range of 2-3 before brushing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗