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Biomedical subjects

S Ebisu

Publications and source records attributed to S Ebisu.

At least 55 records · Page 3Linked to original sources
PubMed1998

Participation of cathepsins B and D in apoptosis of PC12 cells following serum deprivation.

Cathepsin D, a lysosomal aspartic proteinase, has been shown to induce apoptosis of HeLa cells when overexpressed. To further understand regulatory mechanisms of cathepsin D-induced cell death, we examined whether lysosomal cysteine and aspartic proteinases are involved in apoptosis of PC12 cells following serum deprivation. In serum deprived culture, PC12 cells overexpressing cathepsin D died more rapidly than wild-type cells. When the active forms of cathepsins B and D were examined during the apoptotic process of wild-type cells, the amount of cathepsin B was drastically reduced 24 hr after the onset of culture, whereas that of cathepsin D considerably increased. The viability of PC12 cells overexpressing cathepsin B was significantly higher in serum-deprived culture than wild-type cells. In this situation, the amount of the cathepsin B protein did not decrease. The results suggest that there exists an apoptotic pathway regulated by lysosomal cathepsins B and D.

Animals↗
PubMed1998

Antibacterial activity of cured dental resin incorporating the antibacterial monomer MDPB and an adhesion-promoting monomer.

In this study, the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) and an adhesion-promoting phosphoric monomer were incorporated into Bis-GMA-based dental resin and its antibacterial activity after curing was investigated. The experimental resin containing MDPB and 10-methacryloyloxydecyl dihydrogen phosphate (MDP) was polymerized and washed with methanol, and the bacteriostatic and bactericidal effects against Streptococcus mutans were determined. Growth of S. mutans was strongly inhibited by contact with the surface of cured MDPB/MDP-containing resin, although the bactericidal effect was small. Cured MDPB/MDP-containing resin also showed an inhibitory effect against in vitro plaque formation on its surface by S. mutans. The bactericide immobilized in Bis-GMA-based resin demonstrated bacteriostatic activity as a contact antimicrobial even when adhesion-promoting phosphoric monomer was incorporated into the materials.

Adhesives↗
PubMed1998

Effect of enamel and dentin surface wetness on shear bond strength of composites.

PURPOSE: This study investigated the effect of the wetness of human enamel and dentin surfaces on the shear bond strength of composites. MATERIAL AND METHODS: Seven dentin bonding systems were used. Three methods of preparing the enamel or dentin surface before applying primer or bonding agent were adopted as test conditions: wet (blot dried), semidry (3-second air blast), and dry (15-second air drying). Shear bond strength was measured with a universal testing machine. Mean bond strengths were analyzed with analysis of variance and Scheffe's F-test. Enamel and dentin surfaces were observed by a dissecting microscope after shear bond testing. RESULTS: Enamel specimens tested by all systems and dentin tested by two systems did not reveal significant differences in shear bond strengths (p > 0.05). Among dentin specimens tested by two systems with water-based primers, the shear bond strength values of the dry technique group were higher than those of the other two groups (p < 0.05). However, among dentin specimens tested by systems having acetone-based primers or bonding agents, bond strength values of the wet or semidry technique groups were higher than those of the dry technique group (p < 0.05). CONCLUSION: It was concluded that some water might be needed by dentin surfaces or for primers to obtain high bond strength on the dentin surface, but that drying methods did not affect bonding strength to enamel surfaces either before priming or after conditioning.

Analysis of Variance↗
PubMed1998

Antibacterial activity of dentine primer containing MDPB after curing.

OBJECTIVES: A monomer methacryloyloxydodecylpyridinium bromide (MDPB) has antibacterial activity before polymerization. Furthermore, the antibacterial agent is immobilized by the polymerization of MDPB and the resin-based material incorporating MDPB is able to show an antibacterial effect even after being cured. The purpose of this study was to investigate the antibacterial effect of a dentine primer containing MDPB after curing. METHODS: The inhibitory effect of a cured MDPB-containing primer on the growth of Streptococcus mutans, Actinomyces viscosus and Lactobacillus casei was determined by the agar-disc method. The bactericidal activity of cured primer during a 1-h contact period was assessed using S. mutans, and the elution of unpolymerized MDPB was measured with high performance liquid chromatography. RESULTS: Cured MDPB-containing primer showed an inhibitory effect on the growth of all species which were in contact with the specimen surface, and displayed a little bactericidal effect on S. mutans without releasing any unpolymerized antibacterial components. CONCLUSION: Incorporation of antibacterial monomer MDPB into dentine primer is beneficial for providing antibacterial activity after curing.

Actinomyces viscosus↗
PubMed1998

Regional bond strengths of self-etching/self-priming adhesive systems.

The purpose of this study was to measure the regional tensile bond strengths (TBS) at various portions of human tooth enamel and dentin, and to observe the resin-dentin interfaces of two commercially available self-etching/self-priming adhesive systems by scanning electron microscopy (SEM). Twelve extracted human cuspid teeth were used to measure TBS and four additional teeth were used for scanning electron microscopy (SEM). Outer enamel and dentin were removed from the labial tooth surfaces to form a long cavity preparation into middle dentin extending from the mid-crown to the apex of the root within the same tooth. Either Clearfil Liner Bond 2 (LB 2, Kuraray) or Fluoro Bond (FB, Shofu) was bonded to the surfaces, and covered with resin-composite. The resin-bonded teeth were serially sliced at right angles to the long axis of the tooth, and the bonded surfaces were trimmed to give a bonded cross-sectional surface area of 1 mm2 for TBS tests. LB 2 and FB showed significantly higher TBS in coronal, cervical and middle root dentin than that in enamel and apical root dentin. SEM showed that the thickness of the hybrid layer of both systems was about 1.0 microm in coronal, cervical and middle root dentin, and less than 0.5 microm in apical root dentin. These results suggested that the self-etching/self-priming systems produce good adhesion in coronal, cervical and middle root dentin by creating thin hybrid and transitional layers, but bonding to enamel and apical root dentin should be improved.

Acid Etching, Dental↗
PubMed1998

Effect of resin monomer composition on toothbrush wear resistance.

The purpose of this study was to compare the toothbrush abrasion resistance of seven different experimental resins which were made by changing the composition of resin monomers. The experimental resins were made by mixing four kinds of dental resin monomers (Bis-GMA, UDMA, TMPT and TEGDMA), camphorquinone (1 wt%), dimethylaminoethyl methacrylate (2 wt%) and 2,6-di-tert-butyl-p-cresol (0.05 wt%). The resin specimens were stored in air for 2 weeks, and then put on a toothbrush abrasion testing machine. After 100000 strokes, the wear loss of each specimen was determined by weight change during the wear test. TMPT-TEGDMA resin showed the most wear resistance, while Bis-GMA- and UDMA-based resins showed increased wear resistance with an increased content of TEGDMA. Also, a inverse relationship between the microhardness number and the amount of wear of the respective resins was confirmed.

Analysis of Variance↗
PubMed1998

Antibacterial activity of proprietary self-etching primers.

PURPOSE: To determine and compare the in vitro antibacterial activity of three self-etching primers. MATERIALS AND METHODS: LB primer (Liner Bond 2), FB primer (Fluoro Bond), and MB conditioner (Tokuso Mac Bond) were evaluated. The antibacterial activity against Streptococcus mutans, Lactobacillus casei, and Actinomyces viscosus was assessed using the agar disc-diffusion method. Twenty microliters of each primer were impregnated into a paper disc and placed on a Brain Heart Infusion agar plate inoculated with a bacterial suspension. The size of inhibition zones produced around the specimens was measured after 48 hours of incubation of the plate. In addition, 20 microliters of each primer was added to a 1 ml suspension of S. mutans adjusted to 1 x 10(6), 1 x 10(5), or 1 x 10(4) CFU/ml in phosphate buffered saline and kept in contact for 30 seconds. The number of viable bacteria after contact with each primer was determined. The results were analyzed by ANOVA and Fisher's PLSD test (P < 0.05). RESULTS: LB primer and FB primer produced inhibition zones against S. mutans and A. viscosus, and MB conditioner produced an inhibition zone only against A. viscosus. No inhibition zones were produced by any of the primers against L. casei. The three primers completely killed 1 x 10(4) CFU of S. mutans within 30 seconds of contact. When 1 x 10(5) or 1 x 10(6) CFU of bacterial cells were kept in contact, significant differences in the number of recovered viable cells were found among the three primers with MB conditioner being the most bactericidal. LB primer had little bactericidal activity and the mean reduction of viable bacteria by FB primer and MB conditioner was approximately 30% and 65%, respectively.

Actinomyces viscosus↗
PubMed1997

An immunohistochemical study on the localization of Porphyromonas gingivalis, Campylobacter rectus and Actinomyces viscosus in human periodontal pockets.

The localization and distribution of Porphyromonas gingivalis, Campylobacter rectus and Actinomyces viscosus were studied in human periodontal pockets. After obtaining voluntary consent from 9 patients, 12 teeth and their surrounding periodontal tissue with advanced adult periodontitis were extracted carefully so as not to change the structure of the periodontal pockets. The specimens were processed into serial sections. One of the sections was stained with Brown & Brenn-modified Gram stain to observe the distribution of bacteria. The others were stained immunohistochemically by the Labelled Streptavidin Biotin method (LSAB method) using specific rabbit antibodies against selected bacteria. Some bacteria could be found within epithelial cells. P. gingivalis was found in 9/12 of the samples examined. Small aggregates of P. gingivalis were scattered in all parts of the periodontal pockets, and some of these aggregates could be seen in close contact with the epithelium. Conversely, C. rectus was observed in 5/12 of the samples examined and was predominantly located in the middle and deep pocket zones. C. rectus tended to form large clumps in both the tooth-attached and epithelium-associated plaque area. A. viscosus was observed in 7/12 of the samples examined and was localized predominantly in the tooth-attached plaque area, especially in the shallow and middle pocket zones. Although unexpected spills of unattached plaque from periodontal pockets was possible, immunohistochemical staining with species-specific antibodies was extremely sensitive and revealed the localization and the distribution of periodontal disease-associated bacteria in human periodontal pockets.

Actinomyces viscosus↗
PubMed1996

Cloning, sequencing and expression of an Eikenella corrodens gene encoding a component protein of the lectin-like adhesin complex.

A lectin-like substance (LS), that was isolated from Eikenella corrodens (Ec) 1073, migrated as proteins of about 300 and 45 kDa upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. In this study, we cloned the gene encoding the 45-kDa protein and predicted its structure and function. Based on the N-terminal 23-amino acid (aa) sequence of this protein, we cloned the region for its N-terminus. We cloned the entire gene by means of gene walking using polymerase chain reaction and Southern hybridization. The nucleotide sequences of cloned fragments revealed an open reading frame encoding a polypeptide of 330 aa (M(r), 35748). This ORF displayed high homology to those of porins of Neisseria species. Using the T7-expression system, the 45-kDa protein was produced in E. coli. Our results suggested that the 45-kDa protein of Ec 1073 is a component of the EcLS complex, and that it is the major outer membrane protein.

Amino Acid Sequence↗
PubMed1996

Molecular analysis of the gene encoding a protein component of the Eikenella corrodens adhesin complex that is close to the carbohydrate recognition domain.

A monoclonal antibody against a lectin-like substance (LS) of Eikenella corrodens (Ec) was used for screening the Ec DNA library. Three positive clones that carried an identical 12-kb segment were obtained. A 25-kDa protein, which specifically binds to the antibody, was overproduced in all of the Escherichia coli clones. Deletion analysis showed that the gene encoding the 25-kDa protein was located within a 1.2-kb segment. The nucleotide (nt) sequence of this segment contained an open reading frame encoding a protein of 24600 Da. We purified the 25-kDa protein from the cloned E. coli strain. The sequence of the first 10 amino acids(aa) from the N-terminus of the purified 25-kDa protein agreed with that deduced from the nt sequence. Since the monoclonal antibody used in this study inhibits the physiological activity of EcLS, we concluded that the 25-kDa protein is a component of the adhesin complex, which is located near the carbohydrate recognition domain of lectin in EcLS.

Adhesins, Bacterial↗
PubMed1996

The efficient production of human epidermal growth factor by Bacillus brevis.

A system has been developed for the efficient production of heterologous proteins using Bacillus brevis as a host that secretes large amounts of cell wall protein into the medium. The promoter region and signal peptide-encoding region of the cell wall protein gene were used to construct an expression-secretion vector. Bacterial proteins such as amylases can be produced in large amounts by this system (1 g/l or more), but mammalian proteins such as human alpha-amylase are produced at a low level (one or two orders of magnitude less than for bacterial proteins). The highly efficient secretion of human epidermal growth factor (h-EGF, more than 1 g/l) was obtained with B. brevis HPD31 as the host and plasmid pHY481, derived from B. brevis 481, as the vector. Recombinant hEGF was purified easily from the culture supernatant by two steps. Purified hEGF had the identical NH2-terminal amino acid sequence and COOH-terminal amino acid sequence with those of the authentic hEGF, and it was fully active in biological assays. This recombinant hEGF has been shown to be successful for biological wool harvesting (CSIRO, Australia). These results, in combination with previous results, indicate that foreign proteins of diverse origins can be produced efficiently as functional proteins in B. brevis.

Amino Acid Sequence↗
PubMed1996

The interaction between Ku antigen and REF1 protein mediates negative gene regulation by extracellular calcium.

Through the specific binding of a negative calcium-responsive element to its binding protein in response to extracellular Ca (Ca2+e), negative calcium-responsive element-bearing genes, such as the human parathyroid hormone gene, are negatively regulated by Ca2+e. The Ku antigen mediated negative gene regulation by Ca2+e by interacting with a redox factor protein, REF1. Although sequence-nonspecific DNA binding activity of the Ku antigen has been well characterized, the mechanism of its sequence-specific DNA binding remained obscure. Here, we report that the specific binding of the Ku antigen to another protein, REF1, leads to DNA-protein complex formation with a novel sequence specificity and thereby regulates gene expression.

Amino Acid Sequence↗
PubMed1996

Effects of hexafluorosilicate on the precipitate composition and dentine tubule occlusion by calcium phosphate.

OBJECTIVES: To improve the calcium phosphate precipitation (CPP) method for the occlusion of dentine tubules with calcium phosphate, the addition of calcium hexafluorosilicate (CaSiF6) to CPP solution was evaluated in vitro with respect to its occluding capacity and the composition of the precipitate. METHODS: The occlusion of dentine tubules was evaluated by SEM observations and by measurements of dentine permeability. The composition of the precipitate was determined by measuring the calcium to phosphorus (Ca/P) ratio of the precipitate in dentine tubules by energy dispersive X-ray spectroscopy (EDS). RESULTS: The addition of CaSiF6 to the CPP solution resulted in an increase of the Ca/P ratio in the precipitate not only on the dentine surface but also inside the dentine tubules; indicating that the precipitate became more apatitic in nature. The addition of CaSiF6 had no effect on occluding capacity in terms of measurements of dentine permeability or SEM observations. Dentine permeability decreased to approximately 4% of pretreatment values and the dentine tubules were occluded for approximately 10-15 microns from the dentine surface. CONCLUSION: It is concluded that the addition of CaSiF6 to CPP solution was desirable, since it provided a more apatitic precipitate in the dentine tubules, not only on the dentine surface but also inside the tubules, and there were no drawbacks with respect to its occluding capacity.

Apatites↗
PubMed1996

A clinical study of direct pulp capping applied to carious-exposed pulps.

Direct pulp capping of carious-exposed pulp was performed on 44 teeth. We evaluated the success rates of these cases, and analyzed the relationships between the success rates and their clinical findings. Furthermore, we examined the length of time necessary for adequate postoperative follow-up. The success rate in this study was 81.8%. Age of the patients, type of teeth, responses to thermal stimuli and percussion, and the diameter of pulpal exposure had no bearing on the success rate. However, the degree of bleeding on pulpal exposure was related to the success rate (p = 0.042). The success rates of cases in which postoperative follow-up periods were 3 to 18 months were similar (80 to 83%), whereas those with follow-up for 21 months (91.7%) and 24 months (100%) showed higher success rates. These results showed that direct pulp capping was applicable to carious-exposed pulp, and the degree of bleeding is indicative of the prognosis of this treatment. The length of time necessary for adequate postoperative follow-up was suggested to be 21 months.

Adult↗
PubMed1996

Regional strengths of bonding agents to cervical sclerotic root dentin.

The regional bond strengths of three current-generation bonding systems (All Bond 2, Scotchbond Multi-Purpose, and Clearfil Liner Bond 2) were measured in natural wedge-shaped defects in the cervical area of extracted human teeth. A microtensile testing method was used to compare the strengths of resin bonds made to occlusal margins with those made to gingival margins. Controls consisted of normal teeth which had artificial wedge-shaped defects, of the same depth and dimension, created with a high-speed bur. The results indicated that there were no regional differences in bond strength, although bonds made to natural lesions were from 20 to 45% lower than those made to normal dentin in artificially created wedge-shaped defects, depending on the bonding agent. Scanning electron microscopy revealed that Clearfil Liner Bond 2 created the thinnest hybrid layers, which were difficult to measure in the natural lesions. The natural lesions contained sclerotic dentin, whereas the artificial lesions were composed of normal dentin. Although the bond strengths to sclerotic dentin were lower than those to normal dentin, the absolute values (ca. 16 to 17 MPa) were high relative to previous-generation bonding agents.

Acid Etching, Dental↗
PubMed1995

Quantitative analysis of immunoglobulins and inflammatory factors in human pulpal blood from exposed pulps.

The levels of immunoglobulins (IgG, IgA, and IgM) and inflammatory factors (elastase, prostaglandin E2, interleukin-1 alpha, interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha) in the blood of human dental pulp were quantified, using enzyme-linked immunosorbent assays. The pulpal blood samples were obtained with nylon fiber pellets from normal and inflamed dental pulp at pulp sites exposed on pulpectomy. Statistically significant differences between normal and inflamed pulp were found in the levels of IgG (p < 0.01), IgA (p < 0.05), IgM (p < 0.01), elastase (p < 0.05), and prostaglandin E2 (p < 0.01). These findings indicate that these factors play an important role in the pathogenesis of pulpal disease, and the sampling methods used in this study are useful for examination of pulpal inflammation.

Biomarkers↗
PubMed1995

Immunoglobulins in periapical exudates of infected root canals: correlations with the clinical findings of the involved teeth.

This study quantified the concentrations of IgG and IgA in the periapical exudates obtained from 69 single-rooted teeth using enzyme-linked immunosorbent assays, and examined their correlation with clinical findings of the involved teeth. Changes in the levels of these immunoglobulins during root canal treatment were also investigated. The average levels of IgG (85.61 mg/ml) was significantly higher than that of IgA (0.65 mg/ml) (P < 0.001). The exudates from the canals with large lesions (> or = 1 cm in diameter on radiographs) showed significantly higher IgG and IgA levels than small lesions (< 1 cm in diameter) (P < 0.01). The tendency for these to be a decrease in the levels of IgG and IgA was observed following the root canal treatment. These observations suggest that IgG and IgA are involved in the immunopathogenesis of periapical lesions.

Bacterial Infections↗