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Biomedical subjects

K Kozai

Publications and source records attributed to K Kozai.

18 recordsLinked to original sources
PubMed1999

Intrafamilial distribution of mutans streptococci in Japanese families and possibility of father-to-child transmission.

The purpose of this study was to investigate the intrafamilial distribution of mutans streptococci in Japanese families using chromosomal DNA fingerprinting with three endonucleases; EcoRI, HindIII and HaeIII. The analysis of 1,908 isolates cultured from the dental plaque of 76 subjects from 20 families (20 married couples and 36 of their children) resulted in the identification of 144 genotypes containing 114 strains of Streptococcus mutans (serotype c, 66.7%; e, 12.5%) and 30 strains of S. sobrinus (d, 13.2%; g, 7.6%). A mean of 1.89 genotypes (from one to four) was harbored in individual subjects, and a mean of 4.10 genotypes from two to seven was harbored in individual families. Among the 70 genotypes found in the children, 36 (51.4%) were in agreement with their mothers and 22 (31.4%) were in agreement with their fathers. The other genotypes (18.6%) did not correspond with the parents. Homologous strains between parents were found in only two couples. This result showed that fathers or others as well as mothers can be sources of transmission. Further, the serotype d, e and g strains showed significantly higher probabilities of transmission than serotype c.

Adult↗
PubMed1999

Effect of oleanolic acid-cyclodextrin inclusion compounds on dental caries by in vitro experiment and rat-caries model.

Earlier work in vitro showed that oleanolic acid (OA) was a potential inhibitor of insoluble glucan (ISG) synthesis from mutans streptococci (MS). In this study, two oleanolic acid-cyclodextrin inclusion compounds (OA-CDs), oleanolic acid-G1-beta-cyclodextrin (OA-G1-beta CD) and oleanolic acid-beta-cyclodextrin (OA-beta CD), were assayed for their effects on ISG synthesis from Streptococcus mutans MT8148R, and on the growth of oral bacteria. OA-beta CD inhibited ISG synthesis by 55.3 and 37.4% at 62.5 and 15.6 micrograms/ml of OA, respectively. Both OA-CDs inhibited the growth of MS, S. sanguis, and S. salivarius at 4 to 8 micrograms/ml of OA. The anticariogenic effect of the OA-beta CD was examined in a rat-caries model. Rats in the infected control groups showed the highest caries score. The infected treatment group B (0.5% OA in diet) showed lower scores than the control group. These results suggest that OA-beta CD is a potential anti-caries agent.

Animals↗
PubMed1997

Effects of various types of Triton X on the susceptibilities of methicillin-resistant staphylococci to oxacillin.

We examined the effect of six types of the nonionic detergent Triton X on the susceptibilities of methicillin-resistant staphylococci to oxacillin. We used five methicillin-resistant Staphylococcus aureus isolates and 17 methicillin-resistant coagulase-negative staphylococci isolates. All strains of S. aureus, S. epidermidis and S. sciuri had enhanced susceptibility to oxacillin following exposure to the types of Triton X having 7-13 polymerized ethylene oxides. These strains were altered from homogeneously resistant to heterogeneously resistant by Triton X-100. Those types of Triton X that affected the resistance level also promoted the release of lipoteichoic acid. These results and those of previous studies suggest that Triton X might act on factors other than the mecA or femA products.

Detergents↗
PubMed1997

A long-term survey of methicillin-resistant Staphylococcus aureus in the oral cavity of children.

Methicillin-resistant Staphylococcus aureus (MRSA), an indigenous bacteria in healthy people, often causes nosocomial infections. If the host human becomes compromised, MRSA can cause a serious infection. The long-term colonization of MRSA increases this risk. The purpose of this study was to demonstrate the incidence of S. aureus and MRSA colonization in the oral cavities of healthy children, and to examine the stability of identical strains of MRSA over a long-term period. Fourteen children were examined in two stages (first stage: 1987-88, second stage: 1992-93). Five of the 14 children were negative for S. aureus in both stages, seven children were positive in both stages and two children were positive in only the second stage. The children who were colonized with S. aureus in the first stage always harbored the bacteria in the second stage. Of the seven children that were positive for S. aureus in both stages, three persisted in carrying MRSA. We compared two MRSA strains isolated from the same children in both stages by coagulase typing, antibiogram typing and DNA fingerprinting. In two children, the strains showed the same coagulase types, similar antibiograms and similar DNA fragment profiles. These data strongly suggest that identical strains of MRSA persisted in the oral cavities for more than five years, and that the oral cavity can serve as a reservoir for MRSA with the potential to cause nosocomial infections.

Carrier State↗
PubMed1991

Changes in strains of mutans streptococci induced by treatment with chlorhexidine varnish.

Isolates of mutans streptococci were obtained from the dental plaque of ten subjects before and after the subjects had been free of detectable mutans streptococci for a mean period of 14.6 weeks (range, from two to 36 weeks). The mutans streptococci had been rendered undetectable by chlorhexidine varnish treatment. Examination of the restriction endonuclease analysis (REA) patterns of the isolates revealed that all ten subjects had one strain (REA type) after re-appearance of the mutans streptococci that was identical to one that had been present before the varnish treatment. In six of the ten subjects, only one strain was detected both before and after treatment. Each of the other four subjects appeared to gain a new strain after treatment; one of the four appeared to lose one strain, and another, four strains. The ability of strains to persist after the period of undetectability seemed unrelated to their resistance to chlorhexidine or to their ability to exhibit insoluble glucan-mediated adhesion. In the subjects harboring multiple REA types, one-seventh of the tooth surfaces sampled harbored two strains simultaneously, suggesting an inability of either strain to exclude the other aggressively. Overall, the study indicated that every subject receiving chlorhexidine varnish therapy had a primary strain of mutans streptococcus that re-emerged after treatment. In contrast, secondary strains were highly susceptible to being lost or gained.

Adolescent↗
PubMed1990

Proton nuclear magnetic resonance studies of the structure of the Fc fragment of human immunoglobulin G1: comparisons of native and recombinant proteins.

The structure of the Fc fragment of human IgG1 immunoglobulin is compared for the native and recombinant proteins. A recombinant human Fc fragment was expressed by an E. coli system [Kitai K., Kudo T., Nakamura S., Masegi T., Ichikawa Y. and Horikoshi K. (1988) Appl. Microbiol. Biotechnol. 28, 52-56]. The recombinant protein, which presumably lacks oligosaccharides, was used along with the native human Fc fragment obtained by proteolytic digestion of a myeloma IgG1 protein. 1H NMR has been employed along with circular dichroism and fluorescence spectroscopy to discuss the structure of these two types of proteins. It has been concluded that (1) the overall structure of the recombinant protein is quite similar to that of the native protein, which possesses asparagine-linked oligosaccharides, but (2) a significant difference in structure exists in the neighborhood of the glycosylation site. The difference in the effector functions for the two kinds of the Fc proteins has been briefly discussed in terms of the structural change detected by 1H NMR.

Amino Acid Sequence↗
PubMed1988

Production of granulocyte colony-stimulating factor by acute myelomonocytic leukemia cells.

Two patients with acute myelomonocytic leukemia (AMMoL) were tested to determine whether or not their cells produced granulocyte colony-stimulating factor (G-CSF). Using the NFS-60 bioassay method, relatively high levels of G-CSF were demonstrated in the serum pre-treated with acid-dialysis and in the media conditioned by leukemia cells. Northern blot analysis for G-CSF using cDNA as a probe revealed that G-CSF production was increased at the mRNA level in the cells. No rearrangement at the DNA level, however, was observed by genomic Southern analysis. Our data indicate that the leukemic cells in AMMoL probably have the capacity to synthesize and secrete G-CSF.

Aged↗
PubMedDate not supplied

In vitro study of antibacterial and antiadhesive activities of fluoride-containing light-cured fissure sealants and a glass ionomer liner/base against oral bacteria.

The aim of this study was to estimate the antibacterial and anti-adhesive properties of light-cured pit-and-fissure sealants containing fluoride (Teethmate F-1, TF; UltraSea-1 XT, US) or not containing fluoride (Teethmate A, TA)- and glass ionomer liner/base containing fluoride (Vitrebond, VB) against oral bacteria in vivo. VB inhibited the growth of S. mutans, S. oralis and L. casei aerobically and anaerobically, and TA and US inhibited the growth of only S. mutans aerobically. The numbers of adherent cells mediated by insoluble glucan for all materials were lower than that for the control tooth. The numbers of adhesional cells not mediated by insoluble glucan were larger than that for the control tooth. VB showed the highest concentration of fluoride released throughout the four-week observation period, and had the highest pH value. In this study, VB showed superior antibacterial action and fluoride-release compared with the other three materials.

Aerobiosis↗
PubMedDate not supplied

Residual contamination of toothbrushes by microorganisms.

Procedures for maintaining the cleanliness of oral cleaning instruments have been discussed infrequently. S. mutans and pathogenic microorganisms can be transferred readily when a toothbrush is used, increasing the risk of dental caries and infectious diseases. It is suggested that sterilization equipment or specific detergents be used.

Bacteria↗
PubMedDate not supplied

In vitro susceptibility of Staphylococcus aureus including MRSA to four disinfectants.

The spread of nosocomial infections caused by pathogenic organisms such as methicillin-resistant S. aureus (MRSA) has prompted the dental community to focus more attention on certain control strategies. In the present study, we tested the abilities of the four skin disinfectants (povidone iodine, benzalkonium chloride, chlorhexidine gluconate, and ethanol) to prevent horizontal transmission of MRSA in the dental office. The bactericidal activities of the disinfectants were evaluated by the decrement over time of viable cell numbers of four clinical isolated strains of S. aureus: two MRSA strains and two methicillin-sensitive S. aureus (MSSA) strains. The most effective disinfectant was 70 percent ethanol, which eradicated both MRSA and MSSA in less than three minutes. The 0.1 percent chlorhexidine gluconate proved the least effective of four disinfectants. More than 10(2) bacteria survived despite exposure to it for thirty minutes.

Anti-Infective Agents, Local↗
PubMedDate not supplied

New tongue protector to prevent decubital lingual ulcers caused by tongue thrust with myoclonus.

We treated tongue ulcers in a twenty-two-month-old male child with Gaucher disease and several neuronopathic symptoms, including frequent convulsions. Because the patient was always thrusting his tongue and biting with his upper and lower primary incisors during the myoclonus and convulsions, traumatic decubital ulcers on the dorsum and ventral surface of the tongue were formed. During the convulsions, bleeding and pus discharges were observed. For the protection of the tongue from the teeth, a tongue protector was fabricated from a soft silicone relining material used for dentures. The protector covered the mandibular primary central incisors, the alveolar ridge, and the ventral surface, apex and dorsum of the tongue. The ulcer symptoms completely disappeared after two months of using the protector.

Dental Care for Chronically Ill↗