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Biomedical subjects

T Ikemi

Publications and source records attributed to T Ikemi.

14 recordsLinked to original sources
PubMed1998

Rapid isolation of chromosomal DNA from oral streptococci and polymerase chain reaction-oriented restriction fragment-length polymorphism analysis for genetic heterogeneity.

We have extensively modified the published method for the lysis of gram-positive bacteria to isolate chromosomal DNA from only 1 ml of oral streptococcal overnight culture. Cells were incubated with lysozyme and R Nase A in the presence of polyethylene glycol. After centrifugation, cells were lysed with sodium dodecyl sulfate and proteinase K. Following ethanol precipitation, sodium dodecyl sulfate solution was added to the residue, and the pellet was completely dispersed by incubating at 65 degrees C. The chromosome was purified by extraction over phenol and chloroform. Two regions corresponding to the ribosomal RNA (rrn) operon and the glucosyltransferase gene were amplified using the chromosome from Streptococcus mutans and Streptococcus sobrinus by polymerase chain reaction (PCR). Genetic heterogeneity was assessed by restriction fragment-length polymorphism (PCR-RFLP). The PCR-RFLP analysis readily allowed us to subtype each strain, suggesting that the strategy presented here will provide a useful tool to verify epidemiological studies at the molecular level.

Base Sequence↗
PubMed1996

Evaluation of three individual glucosyltransferases produced by Streptococcus mutans using monoclonal antibodies.

We previously established murine hybridomas producing a monoclonal antibody monospecific against three glucosyltransferases (I, SI and S) of Streptococcus mutans which contribute to dental caries formation. Here, we developed a new immunochemical technique (cross-dot system) with which individual levels of glucosyltransferases expressed by S. mutans can be evaluated. We also examined glucosyltransferase production and in vitro artificial plaque formation by a reference strain and several clinical isolates of S. mutans. The findings indicate that the levels of glucosyltransferases produced greatly vary with the cells and the culture medium, and that the cells producing high levels of both glucosyltransferase-SI and glucosyltransferase-I enzymes may possess high in vitro artificial plaque forming ability. We suggest that the cross-dot system will be useful for estimating the cariogenic potential of S. mutans isolates.

Antibodies, Monoclonal↗
PubMed1994

Effects of lining materials on the composite resins shrinkage stresses.

Recently, three types of lining materials have been used in dental clinics, conventional powder-liquid glass ionomer cement, light-cured powder-liquid glass ionomer cement and a light-cured single paste type. This study compared the effects of these lining materials on the shrinkage stress of light-cured composite resins during the early setting stage, when polymerization shrinkage occurs. After the second irradiation, the shrinkage stress of composite resins lined with light-cured powder-liquid type cements was approximately 1.0 to 2.2 MPa when the lining application was 1.5 mm and 0.5 mm thick, respectively, demonstrating that a thicker lining application decreased shrinkage stress. The single paste type was only slightly effective in reducing shrinkage stress in composite resins. Although the sample lined with conventional powder-liquid type showed that stresses were less affected by the thickness of the lining, and had the lowest shrinkage stress of all conditions tested, greater exfoliation from the composite resin or the cavity occurred compared to that occurring with other materials.

Acrylic Resins↗
PubMedDate not supplied

A histopathological study of direct pulp capping with adhesive resins.

This study evaluated the histological pulp responses of four different adhesive resin systems placed directly on exposed pulp tissue. Gap formation between the respective resin and cavity walls was observed and correlated to the pulpal response. Occlusal cavity preparations creating mechanical pulp exposures were prepared in molars of wistar rats. Preparations were filled using one of the following resin systems: 1) Superbond C&B system, 2) Clearfil Liner Bond system, 3) Tokuso Light Bond system, and 4) Scotchbond Multi-Purpose One All system. Although there were no significant differences in the pulpal responses after 3 days, significant differences were observed after 7 days. Results showed that the Superbond C&B system induced only a slight initial reaction, while secondary dentin was observed at the 30-day postoperative evaluation period. The Clearfil Liner Bond system showed a slight initial reaction to the materials, but exhibited slight pulpal necrosis and formation of secondary dentin at the 90-day evaluation period. The Tokuso Light Bond and One All systems showed severe pulpal reactions at all evaluation periods with no formation of secondary dentin. Microleakage formation correlated with the histopathological responses. Superbond C&B exhibited no microleakage, and only slight microleakage was observed when the Clearfil Bond system was used. The Tokuso and One All systems exhibited a wide area of microleakage. Further in vivo study evaluating the clinical use of adhesive resins for pulp capping is necessary to determine which resin systems may be used for direct pulp capping without incurring severe damage to pulpal tissue.

Animals↗