PubMed Health⌕ Search

Biomedical subjects

S Ebisu

Publications and source records attributed to S Ebisu.

At least 73 records · Page 4Linked to original sources
PubMed1995

Effects of fluoride on the calcium phosphate precipitation method for dentinal tubule occlusion.

Use of the calcium phosphate precipitation (CPP) method makes possible the occlusion of dentinal tubules to approximately 10 to 15 microns from the dentinal surface, and thus shows good potential for the treatment of dentin hypersensitivity. The precipitate formed in the dentinal tubules by the CPP method is, however, not apatite [HAP; Ca10(PO4)6(OH)2], a component of tooth and bone, but dicalcium phosphate dihydrate (DCPD; CaHPO4.2H2O). Since fluoride enhances the conversion of DCPD to HAP, we evaluated the effects of fluoride on the texture of the precipitate formed by the CPP method and on its capacity to occlude dentinal tubules in this in vitro study. CPP solution (1.0 mol/L CaHPO4.2H2O dissolved in 2.0 mol/L H3PO4) was applied to a dentin disk and was subsequently neutralized with a post-treatment solution (1 mol/L NaOH, from 0 to 0.1 mol/L NaF). Scanning electron microscopy revealed that the precipitate occluded dentinal tubules to a depth of approximately 10 to 15 microns from the dentinal surface, regardless of the NaF concentration (from 0 to 0.1 mol/L) in the post-treatment solution. Also, dentin permeability was reduced to 15% by the CPP treatment regardless of the NaF concentration. The Ca/P molar ratio of the precipitate, measured by x-ray micro-analysis, was higher (1.25 +/- 0.04) in the presence of NaF than in its absence (1.03 +/- 0.01). For further identification of the precipitate formed in the dentinal tubules, the same procedure was used in glass tubes (diameter, 1 mm), so that a larger amount of precipitate would be obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium Phosphates↗
PubMed1995

Tensile bond strength and SEM evaluation of caries-affected dentin using dentin adhesives.

Tensile bond strength measurements are commonly used for the evaluation of dentin adhesive systems. Most tests are performed using extracted non-carious human or bovine dentin. However, the adhesion of resins to caries-affected dentin is still unclear. The objectives of this study were to test the hypothesis that bonding to caries-affected dentin is inferior to bonding to normal dentin, and that the quality of the hybrid layer plays a major role in creating good adhesion. We used a micro-tensile bond strength test to compare test bond strengths made to either caries-affected dentin or normal dentin, using three commercial adhesive systems (All Bond 2, Scotchbond Multi-Purpose, and Clearfil Liner Bond II). For scanning electron microscopy, the polished interfaces between the adhesive bond and dentin were subjected to brief exposure to 10% phosphoric acid solution and 5% sodium hypochlorite, so that the quality of the hybrid layers could be observed. Bonding to normal dentin with either All Bond 2 (26.9 +/- 8.8 MPa) or Clearfil Liner Bond II (29.5 +/- 10.9 MPa) showed tensile bond strengths higher than those to caries-affected dentin (13.0 +/- 3.6 MPa and 14.0 +/- 4.3 MPa, respectively). The tensile bond strengths obtained with Scotchbond Multi-Purpose were similar in normal and caries-affected dentin (20.3 +/- 5.5 MPa and 18.5 +/- 4.0 MPa, respectively). The hybrid layers created by All Bond 2 in normal dentin and by Clearfil Liner Bond II in normal or caries-affected dentin showed phosphoric acid and sodium hypochlorite resistance, whereas the hybrid layers created by All Bond 2 in caries-affected dentin and those created by Scotchbond Multi-Purpose to normal and caries-affected dentin showed partial susceptibility to the acid and sodium hypochlorite treatment. The results indicate that the strength of adhesion to dentin depends upon both the adhesive system used and the type of dentin. Moreover, the quality of the hybrid layer may not always contribute significantly to tensile bond strength.

Analysis of Variance↗
PubMed1995

Duration of dentinal tubule occlusion formed by calcium phosphate precipitation method: in vitro evaluation using synthetic saliva.

The use of a calcium phosphate precipitation method occluded dentin tubules with apatitic mineral and, thus, showed good potential for the treatment of dentin hypersensitivity. The aim of this study was to elucidate the occluding behavior of the precipitate in the oral environment. Dentin disks treated by the calcium phosphate precipitation method, and disks treated with potassium oxalate, NaF, and SrCl2 solutions, were immersed in synthetic saliva, which was regularly replenished so that ionic concentration would be maintained. Treatment of dentin disks by the calcium phosphate precipitation method immediately reduced dentin permeability to 6 +/- 8%. When the disk was immersed in synthetic saliva, dentin permeability remained low, even seven days after immersion. Scanning electron microscopic observation showed no distinct boundary line between the precipitate and intertubular dentin; this indicated further mineralization on the precipitate. Potassium oxalate treatment also reduced the dentin permeability to 8 +/- 3%. However, the dentin permeability gradually but steadily increased with immersion time, reaching 39 +/- 14% at seven days. To elucidate the mechanism underlying dentin permeability changes in synthetic saliva, we immersed the precipitates, i.e., apatitic mineral and calcium oxalate, in a fixed volume of synthetic saliva. When calcium oxalate was immersed in synthetic saliva, there was a large concentration of oxalate ions, indicating dissolution of the calcium oxalate; this phenomenon was ascribed to the increase in dentin permeability. In contrast, calcium and phosphate ions decreased when apatitic powder, the precipitate formed by the calcium phosphate precipitation method, was immersed in synthetic salvia. The decrease in the calcium and phosphate ions in synthetic saliva indicated further precipitation of calcium phosphate on the apatitc precipitate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

A redox factor protein, ref1, is involved in negative gene regulation by extracellular calcium.

A rise in extracellular calcium (Ca2+e) suppresses not only secretion of parathyroid hormone (PTH) but also expression of the PTH gene to ensure constant plasma Ca2+ level. A nuclear protein(s) in a wide variety of cells bound to the specific DNA elements (negative Ca2+ responsive elements, nCaREs) in the human PTH gene in sequence-specific and Ca2+e concentration-dependent manners. Our Southwestern cloning revealed that a redox factor protein (ref1), which was known to activate several transcription factors via alterations of their redox state, belonged to an nCaRE binding protein. The level of ref1 mRNA as well as of its protein was elevated by an increase in Ca2+e concentration. In gel shift assay, anti-ref1 antibody eliminated formation of the nCaRE-protein complex. We also found that there was another protein(s) interacting with nCaREs and ref1. Further, experiments with an antisense-ref cDNA expression vector introduced into cultured cells suggested that DNA (nCaRE)-ref1 interaction led to Ca2+e-mediated transcriptional suppression. Thus, it is concluded that ref1 possesses transcription repressor activity in addition to its function as a transcriptional auxiliary protein.

Animals↗
PubMed1994

Mitogenic stimulation of murine B lymphocytes by the N-acetyl-D-galactosamine specific bacterial lectin-like substance from Eikenella corrodens.

A N-acetyl-D-galactosamine (GalNAc) specific bacterial lectin-like substance from Eikenella corrodens 1073 (EcLS) was found to have potent mitogenic activity when cultured with splenocytes from BALB/c mice. The results indicated that B lymphocytes are the major cell type responding to EcLS. The mitogenic activity of EcLS was dose-dependent, and the optimal concentration was around 5 micrograms/ml. The mitogenic activity did not appear to be due to a bacterial endotoxin, as GalNAc inhibited the mitogenic activity of EcLS, but did not inhibit the activity of lipopolysaccharide isolated from E. corrodens. EcLS stimulated murine B lymphocytes not only to proliferate, but also to differentiate into antibody-secreting cells, as demonstrated by the production of immunoglobulin by B lymphocytes stimulated with EcLS. These findings suggest that EcLS is a novel lectin that not only induces B lymphocyte proliferation, but also differentiation.

Acetylgalactosamine↗
PubMed1994

Interleukin-1 alpha and interleukin-1 beta periapical exudates of infected root canals: correlations with the clinical findings of the involved teeth.

This study quantified the concentrations of interleukin-1 alpha (IL-1 alpha) and interleukin-1 beta (IL-1 beta) 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 factors during root canal treatment were also investigated. The average levels of IL-1 beta (6.57 ng/ml) in periapical exudates were twice that of IL-1 alpha (3.25 ng/ml). The exudates containing pus showed significantly higher IL-1 alpha levels than those from the canals without pus (p < 0.01). The exudates from the canals with small radiolucent areas contained significantly higher IL-1 alpha levels than those from the canals with large radiolucent areas (p < 0.05). The tendency for there to be an increase in the levels of IL-1 alpha and a decrease in the levels of IL-1 beta was observed following root canal treatment. These observations suggest that IL-1 alpha and IL-1 beta are involved in the immunopathogenesis of periapical lesions and that IL-1 alpha and IL-1 beta may play different roles in the healing process of periapical lesions during root canal treatment.

Dental Pulp Diseases↗
PubMed1994

A quantitative comparison of selected bacteria in human carious dentine by microscopic counts.

The levels of selected cariogenic and obligately anaerobic bacteria have been compared in carious dentine taken from fissures, smooth surfaces, and root surfaces. The numbers of infected dentinal tubules were determined by immunohistological staining using species-specific antisera against selected bacteria. Selective localization was observed; mutans streptococci were the predominant bacteria in dentine from fissures and smooth surface coronal caries, but not from root surface caries. The proportion of mutans streptococci was higher in the shallow and middle layers of dentine from fissures and smooth surface coronal carious lesions than from the deep layers. In root surface caries, Actinomyces spp. were the predominant bacteria, and were present at higher levels in the deep layer of root lesions than in the shallow and middle layers. The proportion of Lactobacillus spp. was relatively low despite its high detection frequency in all layers of the three types of carious lesion. Immunohistological staining with species-specific antisera was able to reveal the distribution and the localization of various bacteria in carious dentine.

Actinomyces viscosus↗
PubMed1994

Occlusion of dentinal tubules with calcium phosphate using acidic calcium phosphate solution followed by neutralization.

The occlusion of dentinal tubules with calcium phosphate, by a calcium phosphate precipitation method (CPP method), was investigated in vitro for evaluation of the potential value of this method for the treatment of dentin hypersensitivity. The method consists of treating the dentinal surface with a CPP solution, i.e., an acidic solution that contains both calcium and phosphate, followed by neutralization with basic post-treatment solution. The CPP solutions used in this study ([Ca] = 0.2 - 1.0 mol/L, [PO4] = 0.2 - 4.0 mol/L) were prepared by dissolving Ca(OH)2 or CaHPO4 x 2H2O in H3PO4 or HCl, and 1 mol/L NaOH solution was used for the post-treatment solution. Sections of human dentin disks treated by the CPP method were observed by scanning electron microscopy, and the precipitate in the dentinal tubules was subjected to x-ray micro-analysis. After treatment by the CPP method, dentinal tubules were occluded to a distance of approximately 15 microns from the surface, and the precipitate showed a Ca/P molar ratio of 1.03 +/- 0.01 To obtain a larger amount of precipitated mineral for further analysis, we used the same procedure with glass tubes (inside diameter, 1 mm). Powder x-ray diffraction analysis and FT-IR measurement revealed that the precipitate was dicalcium phosphate dihydrate (CaHPO4 x 2H2O). The instant precipitation of calcium phosphate mineral in the dentinal tubules demonstrated the potential value of the CPP method for the occlusion of dentinal tubules, this occlusion may be useful for the treatment of dentin hypersensitivity.

Calcium Phosphates↗
PubMed1993

Production of a fungal protein, Taka-amylase A, by protein-producing Bacillus brevis HPD31.

An expression-secretion vector, pMK300, was constructed to express the Aspergillus oryzae Taka-amylase A (Taa) cDNA. The promoter and signal peptide regions of the HWP (a major cell wall protein of Bacillus brevis HPD31) gene on pMK300 were efficiently utilized in B. brevis HPD31 and a large amount of Taa (22 mg/l) was secreted into the medium. The HWP signal peptide utilized for secretion of Taa was correctly processed during the protein transport across the membrane. The enzymatic properties of Taa produced by B. brevis HPD31 were the same as those of the Aspergillus oryzae Taa in several respects; specific activity, thermal and pH stabilities, and temperature and pH optima. These results, in combination with previous results, indicate that B. brevis HPD31 could be used to produce extracellularly foreign proteins of diverse origins as functional proteins.

Amino Acid Sequence↗
PubMed1993

Production and characterization of monoclonal antibodies against bacterial lectin of Eikenella corrodens.

A lectin-like substance (EcLS) was purified from the Eikenella corrodens 1073 cell and monoclonal antibodies were produced against it to confirm the role of EcLS in adhesive properties of E. corrodens such as hemagglutination and coaggregation with oral bacteria. Four hybridoma clones were selected. Two of the antibodies were of the IgG1 isotype and the others were of the IgG2b isotype. These monoclonal antibodies inhibited both the hemagglutination of E. corrodens and the coaggregation with Actinomyces viscosus or Streptococcus sanguis. The reactivity of the monoclonal antibody to E. corrodens 1073 was significantly higher than that to E. corrodens 1080 of which adhesive activity was weaker than that of E. corrodens 1073. These findings suggest the difference in adhesive properties is due to the difference in the amount of EcLS expressed on the cell surface. The immunoelectron microscopic study revealed that EcLS of E. corrodens 1073 was localized in the outer space of outer membrane, not in cell surface appendages such as fimbriae where bacteria possessed adhesin. These results suggest that coaggregation of E. corrodens with A. viscosus or S. sanguis was mediated by EcLS.

Antibodies, Monoclonal↗
PubMed1992

Quantitative analysis of immunocompetent cells in human periapical lesions: correlations with clinical findings of the involved teeth.

Human periapical lesions develop as a result of a pathological immune response to continuous stimuli from infected root canals. This study identified the immunocompetent cells in such lesions immunohistochemically and quantified them to examine their interrelationships and correlations with clinical findings. The number of IgG-containing cells in CD4+ cell (Th/i)-rich lesions (> or = 55 CD4+ cells/2 x 10(4) microns 2) was significantly larger than in CD4+ cell-poor lesions (< 55 CD4+ cells/2 x 10(4) microns 2). This indicated that the CD4+ cells and the IgG-containing cells acted together against antigenic stimuli. The proportion of T cells in the mononuclear infiltrates varied with the size of the periapical lesions. The proportion of CD11+ cells (monocytes/macrophages) was significantly larger in lesions which showed a positive reaction to percussion or were tender on palpation than in the lesions without these symptoms. These observations suggest that T cells may play an important role in the development of periapical lesions and that CD11+ cells may be involved in the development of symptoms.

Antigens, CD↗
PubMed1992

The mechanisms of Eikenella corrodens aggregation by salivary glycoprotein and the effect of the glycoprotein on oral bacterial aggregation.

The mechanism of aggregation of Eikenella corrodens 1073 with E. corrodens aggregating factor (EcAF) which was purified from submandibular-sublingual (SM-SL) saliva was investigated. Heating (100 degrees C, 10 minutes) or protease treatment of E. corrodens cells abolished the aggregating activity. The aggregation was inhibited by adding N-acetyl-D-galactosamine (GalNAc) and saccharides which contain a galactose residue at the non-reducing end. The aggregating activity was sensitive to EDTA and was restored by Ca2+ but not by Mn2+ or Mg2+. Neuraminidase treatment of EcAF increased their ability to aggregate. E. corrodens, suggesting that the sialic acids on EcAF interfere with aggregation. These data suggest that the aggregation of E. corrodens 1073 with EcAF is mediated by specific interactions between a bacterial cell surface lectin-like substance and a complementary GalNAc-like receptor. EcAF also aggregated 16 strains of oral bacteria including periodontopathic bacteria such as Porphyromonas (Bacteroides) gingivalis 381 and Actinobacillus actinomycetemcomitans ATCC29522; however, those aggregations were not inhibited by GalNAc. Therefore, EcAF appears to have more than two types of bacterial binding site and plays important roles in accumulation of dental plaque by forming a complex network of plaque bacteria including periodontopathic strains.

Acetylgalactosamine↗
PubMed1992

Morphological characterization of hypersensitive human radicular dentin and the effect of a light-curing resin liner on tubular occlusion.

A dentin biopsy technique was employed to compare the morphological features of hypersensitive and non-sensitive human radicular dentin. Specimens sampled from different areas in the same root surface displaying hypersensitivity or non-sensitivity were prepared for examination in the scanning electron microscope (SEM). Before analysis some specimens were exposed to surface demineralization and digestion of collagen to allow observation of subsurface portions of the dentinal tubules. In another set of observations the potential of a light-curing resin liner to penetrate root dentin in vitro and to maintain tubular occlusion over time following treatment of hypersensitive radicular dentin were examined. Orifices of many dentinal tubules were open in hypersensitive regions while non-sensitive areas generally displayed tubules occluded with mineralized material. SEM-images of HCl-collagenase treated specimens demonstrated the frequent presence of membrane-like structures in tubules of hypersensitive dentin. In non-sensitive dentin these structures were sparse. Topical application of a light-curing resin liner to wedge shaped defects prepared in radicular dentin of extracted human teeth resulted in a surface coating with a resin thickness of 20-50 microns. Resin penetrated dentinal tubules to a depth of more than 5 microns. Dentin biopsies examined 6 months after treatment with the liner showed presence of resin-like material in a majority of the tubules in dentin where hypersensitivity was no longer perceived. In none of the specimens did the liner remain as a surface coating. In areas of recurrent hypersensitivity more than half of the tubules presented with open orifices.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Etching, Dental↗
PubMed1990

Effect of infection with Eikenella corrodens on the progression of ligature-induced periodontitis in rats.

The periodontopathic ability of Eikenella corrodens 1073-R (EcR) on ligature-induced periodontal defects in immunosuppressed and non-immunosuppressed rats was studied bacteriologically and histologically. Silk ligatures were placed around the maxillary second molars of rats, and the rats were divided into eight groups. Four groups received cyclophosphamide (CY), an immunosuppressive agent, the day after ligature placement. On days 3 and 4, the oral cavities of the rats in all four groups were inoculated with 8 x 10(8) cells of live EcR. Rats were sacrificed on d 1, 3, 5, 8, 11 and 18. Alveolar bone resorption of ligated rats was enhanced by the implantation of EcR, although the number of total cultivable bacterial cells from ligated sites was not changed by the implantation of EcR. CY suppressed the number of white blood cells, inflammatory cellular infiltrates in gingival tissue, and repair of periodontal tissue, and enhanced bone destruction. The implantation of EcR in the ligature- and CY-treated rats also enhanced osteoclastic bone resorption. Without ligatures, high doses of CY or EcR inoculum did not result in periodontal destruction. These results indicate that it is possible to establish EcR in conventional rat flora with a ligature and that EcR causes osteoclastic bone resorption in this model.

Alveolar Bone Loss↗
PubMed1990

Local ofloxacin delivery using a controlled-release insert (PT-01) in the human periodontal pocket.

PT-01, a controlled-release insert, was developed for topical chemotherapy in periodontal disease. It is a soluble insert that consists of fast-release and sustained-release parts containing ofloxacin (OFLX) as an antibacterial agent. In this study, the release profile of OFLX from PT-01 was investigated in vitro. Twelve adult volunteers were administered OFLX as PT-01 or as an aqueous solution into their periodontal pockets, OFLX concentrations in gingival crevicular fluid (GCF) were evaluated from the viewpoint of pharmacokinetics. The in vitro release profile of OFLX from PT-01 showed a biphasic pattern. The release rate of OFLX was relatively rapid in the early phase and slow thereafter. When OFLX aqueous solution was administered into periodontal pockets, the OFLX level in GCF rapidly decreased to be about 1/100 after 30 minutes. When PT-01 was inserted into the pockets, the OFLX level in GCF immediately reached a peak (about 12 mg/ml), and gradually decreased until the 3rd day, and maintained a constant level above 2 micrograms/ml, the effective minimum antibacterial concentration for periodontopathic microorganisms, from the 3rd to 7th day after insertion. No side-effects were observed in the volunteers who received the PT-01 insert. The above results suggest that PT-01 is a suitable pharmaceutical preparation for periodontal chemotherapy.

Adult↗
PubMed1990

Conserved structures of cell wall protein genes among protein-producing Bacillus brevis strains.

Bacillus brevis HPD31 contains a surface (S)-layer protein, termed the HWP, which forms a hexagonal array in the cell wall. The 5' region of the HWP gene was isolated from a DNA library constructed in bacteriophage vector EMBL3 from a partial BamHI digest of the chromosomal DNA. The 3' region contained in a 2.7-kilobase BglII fragment of the DNA was cloned into Escherichia coli, using pUC118 as a vector. On the basis of the chemically determined N-terminal amino acid sequence, the HWP gene was found to encode a polypeptide consisting of 1,087 amino acid residues with a signal peptide of 53 or 23 amino acid residues. The deduced amino acid composition was similar to the chemical amino acid compositions of other S-layer proteins in the predominance of acidic relative to basic amino acids and in the very low content of sulfur-containing amino acids. The deduced amino acid sequence showed high homology (78%) with that of the middle wall protein of B. brevis 47. Furthermore, the multiple 5' ends of the HWP gene transcripts detected on S1 nuclease analysis closely resembled those of the middle wall protein gene transcripts. This complex structure was also conserved (greater than 85%) in the regulatory regions of two other cell wall protein genes isolated from B. brevis HPD52 and HP033, suggesting that the synthesis of the cell wall proteins is intricately regulated through a similar mechanism in protein-producing B. brevis.

Amino Acid Sequence↗