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Biomedical subjects

T Takehara

Publications and source records attributed to T Takehara.

At least 127 records · Page 7Linked to original sources
PubMed1991

Signal transduction pathways in the induction of HLA class I antigen expression on Huh 6 cells by interferon-gamma.

This study investigated the intracellular signal transduction regulating the appearance of HLA class I antigens on Huh 6 cells induced by interferon-gamma. The expression was blocked by a protein kinase C inhibitor, H-7, but not by a calmodulin antagonist, W-7, nor by a protein kinase A inhibitor, H-8, at low dose. The antigen expression was induced by a direct activator of protein kinase C, phorbol myristate acetate, but not by calcium ionophore A23187 nor an analog of cAMP, dbcAMP. Therefore, we concluded that protein kinase C is involved in the expression of HLA class I antigens on Huh 6 cells induced by interferon-gamma but Ca(2+)-calmodulin and cAMP are not.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1991

Two-dimensional flow cytometric analysis of intrahepatic lymphocyte subsets from patients with chronic hepatitis.

Peripheral and intrahepatic lymphocyte subsets were analyzed in 22 patients with chronic hepatitis by two-dimensional flow cytometry. Activated T cells in the liver significantly increased compared with those in the peripheral blood. Helper T cells increased, but the CD4+ cells decreased due to a marked decrease of suppressor inducer T cells. CD8+ cells increased due to a increase of both cytotoxic T and suppressor T cells. Fc-receptor-positive cells, which increased significantly, were not NK cells but Fc-receptor-bearing T cells. In comparison with immunohistochemical methods, flow cytometric analysis enables more objective quantitation and simpler two-color staining of intrahepatic lymphocytes. Our findings using this method suggest that activated T cells and helper T cells have important roles in hepatitis and that hepatocellular injury may be generated not only by cytotoxic T cells but also by Fc-receptor-bearing T cells.

Adult↗
PubMed1991

Effect of calcium ions on cell surface electrostatics of Bacteroides gingivalis and other oral bacteria.

Surface electrostatics of Bacteroides gingivalis and other oral bacteria were examined. A polarization circuit was employed using platinum electrodes exposed in each bacterial suspension and the number of bacteria adsorbed to the anode and cathode were then estimated. In all bacteria (B. gingivalis, Streptococcus sobrinus, S. mutans, S. salivarius, S. sanguis and Actinomyces viscosus), the number of cells adsorbed to the anode were much greater than the number of cells adsorbed to the cathode. Treating these bacteria with calcium ions tended to decrease the ratio of the number of cells adsorbed to the anode to the number of cells adsorbed to the cathode in all bacteria examined. Moreover, in the case of B. gingivalis, the number of cells adsorbed to the anode and cathode was in an inverse relationship to the number counted before calcium ion treatment. These findings indicate that the cell surfaces of oral bacteria are generally negatively charged but only the cell surface electrostatics of B. gingivalis was dramatically affected by calcium ion treatment. Thus, divalent metal bridges such as calcium bridges contribute to the adherence of the periodontopathic bacterium, B. gingivalis rather than to that of other oral bacteria including cariogenic bacteria.

Actinomyces↗
PubMed1991

Periodontal condition of pregnant women assessed by CPITN.

The periodontal conditions of 2424 pregnant and 1565 non-pregnant women were assessed according to the community periodontal index of treatment needs (CPITN). The aim of this survey was to obtain information which is necessary for the planning of preventive programs of periodontal disease for pregnant women. 95% of the pregnant women and 96% of the non-pregnant women had some signs of periodontal disease. The % of pregnant women having 4 or 5 mm pockets was significantly higher than that of non-pregnant women, increased with the month of pregnancy, reached a maximum of 31% in the 8-month group, but decreased to the control level in the 9-month group. These changes were interpreted to suggest that the increase of pocket depth during pregnancy was caused by gingival enlargement rather than by periodontal destruction. The results show that pregnant women had a healthier periodontal condition when compared with non-pregnant women, i.e., the number of sextants with healthy periodontal tissues was higher, the % of people having deep pockets (6 mm or deeper) was lower, and the need for prophylaxis was lower in pregnant than in non-pregnant women. These findings suggest that a special program of periodontal disease prevention for pregnant women is not necessary.

Adolescent↗
PubMed1991

Cloning of a Streptococcus sobrinus gtf gene that encodes a glucosyltransferase which produces a high-molecular-weight water-soluble glucan.

The gtf gene coding for glucosyltransferase (GTF), which produces a water-soluble glucan, was cloned from Streptococcus sobrinus OMZ176 (serotype d) into plasmid vector pBR322. This gene was expressed in Escherichia coli, and the product was purified to near homogeneity. The antigenicity of recombinant GTF (rGTF) was examined with the antisera raised against purified GTF P1, P2, P3, and P4 obtained from S. sobrinus AHT (serotype g). The rGTF reacted only with anti-GTF P1 serum in a Western blot (immunoblot) analysis. The rGTF closely resembled GTF P1 in its molecular mass, Km value for sucrose, optimal pH, primer dependency, and immunological properties. The high-molecular-weight, water-soluble glucan produced by the rGTF also resembled that of GTF P1, which is the most efficient primer donor for primer-dependent, water-insoluble glucan synthesis. Properties of the rGTF were also compared with those of rGTFS, which was purified from E. coli carrying the gtfS gene isolated from Streptococcus downei (previously S. sobrinus serotype h) MFe28. Both rGTF and rGTFS synthesized water-soluble glucan from sucrose without primer dextran, but their characteristics in Km values for sucrose, optimal pHs, and polymer sizes of the glucan were different. Furthermore, the gtf gene did not hybridize with the gtfS gene in a Southern blot analysis. These results showed that rGTF is similar to S. sobrinus AHT GTF P1 but distinct from rGTFS that has been previously purified from E. coli carrying the gtfS gene.

Amino Acid Sequence↗
PubMed1991

Comparison of biological and immunochemical properties indicates that scatter factor and hepatocyte growth factor are indistinguishable.

Scatter factor, a stimulant of epithelial cell motility, and Hepatocyte Growth Factor (HGF) were compared by cross-biological studies using naturally occurring and recombinant proteins in four bioassays. Both scatter factor and HGF produced similar effects in cell motility and DNA synthesis assays. Antibodies to scatter factor or HGF neutralized the biological activities of each cytokine, and in immunoblotting reacted with species of the same Mr. These results, together with the available sequence data, suggest that scatter factor and HGF are the same protein.

3T3 Cells↗
PubMed1991

[Detection of hepatitis C virus RNA in serum during treatment of chronic hepatitis C with interferon alpha].

We estimated HCV RNA in serum of 20 patients with chronic hepatitis C during interferon therapy using a combination assay of reverse transcription and polymerase chain reaction (RT-PCR). RNA was extracted from 200 microliters of serum. The primers were chosen from the NS3 region of prototype HCV RNA sequence. After 40 cycles of PCR, the products were analyzed by Southern hybridization. HCV RNA was detected in 18 of 20 (90%) patients before therapy. In cases with improvement of serum GPT level, HCV RNA became undetectable at 4 weeks of the therapy. However, HCV RNA reappeared within 4 weeks after the therapy in cases with relapse. In the no response group, HCV RNA did not disappear during the therapy. Interferon therapy is beneficial in improvement of viremia of HCV, and the detection of HCV RNA in serum is useful to evaluate the antiviral effect of interferon.

Adult↗
PubMed1991

Substrate specificity of hydrolase activity of the primer-dependent glucosyltransferases from Streptococcus sobrinus.

Four kinds of glucosyltransferases, P1, P2, P3 and P4, were separately purified from the culture supernatant of Streptococcus sobrinus. Their dependencies on primer were analysed. There were two primer-dependent glucosyltransferases (P3 and P4). In the absence of primer 1,6-alpha-D-glucan, P3 was not able to produce glucan from sucrose. However, P3 showed sucrose hydrolase activity, whereas P4 was still able to produce glucan without primer 1,6-alpha-D-glucan. Consequently, glucosyltransferase activity of P4 was incompletely primer-dependent. Both P3 and P4 showed high substrate specificity for sucrose, failing to use melezitose, raffinose, or stachyose as the substrates.

Chromatography, High Pressure Liquid↗
PubMed1991

CPITN assessments in institutionalised elderly people in Kitakyushu, Japan.

A CPITN survey was conducted on 1958 institutionalised elderly people aged 59 years and older at 29 of the 30 public and private institutions in the city of Kitakyushu, Japan. About 60 per cent of the sample was edentulous, and the prevalence of periodontal conditions was high. The percentages of dentate subjects with healthy gingivae, bleeding on probing, calculus, shallow pockets, and deep pockets were 3, 4, 32, 52, and 9 per cent respectively. Half the sextants in the dentate subjects were scored as excluded (less than two teeth), indicating that many teeth were missing. Only very few sextants were healthy. These findings indicate the importance of preventive programmes for periodontal diseases in the younger generations, because (a) dental care for the elderly population becomes more difficult with increasing age and (b) periodontal care, if it is available at all, is provided too late for most people.

Aged↗
PubMed1990

Characterization of the product of the gtfS gene of Streptococcus downei, a primer-independent enzyme synthesizing oligo-isomaltosaccharides.

The gtfS gene, coding for a glucosyltransferase which synthesizes water-soluble glucan and previously cloned from Streptococcus downei strain MFe28 (mutans serotype h) into a bacteriophage vector, was subcloned into a plasmid vector. The gtfS gene products expressed in Escherichia coli were compared to the primer-independent, oligo-isomaltosaccharide synthase in Streptococcus sobrinus strain AHT (mutans serotype g) and shown to resemble it closely in molecular mass, isoelectric point, immunological properties, optimum pH and Km values. The glucans produced from sucrose by the gtfS gene products are alpha-1,6-linked linear oligo-isomaltosaccharides without any branching sites. A similar gtfS gene was also detected on chromosomal DNA from S. sobrinus strain AHT.

Blotting, Western↗
PubMed1990

Purification and characterization of alkaline phosphatase of Bacteroides gingivalis 381.

Cell-associated alkaline phosphatase (ALPase) of Bacteroides gingivalis 381 was found in the outer part of the periplasmic space by using an ultracytochemical procedure. Cell-associated ALPase was solubilized by extraction with 1% Triton X-100, and the solubilized enzyme was purified 904-fold with 5.6% recovery by using affinity column chromatography for mammalian intestinal-form ALPase. The purified enzyme gave a single protein band that corresponded to the enzyme activity band on polyacrylamide gel electrophoresis preparations. A single protein band at a molecular weight of 61,000 was observed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis preparations. The molecular weight of the native enzyme was estimated to be 130,000 by gel filtration with TSK-gel G3000SW. These findings indicate that B. gingivalis ALPase is a homodimer. The optimal pH of the enzyme was between 9.1 and 9.3 in the absence of divalent metal ions and was between 10.1 and 10.3 in the presence of manganese or zinc ions. The apparent km for p-nitrophenylphosphate was 0.037 +/- 0.003 mM (mean +/- standard deviation) at pH 9.2 in the absence of divalent metal ions and 0.22 +/- 0.02 mM at pH 10.2 in the presence of 1 mM manganese ions. Under both of the conditions described above, the purified enzyme was able to hydrolyze casein and O-phosphoserine, suggesting that B. gingivalis ALPase can act as a phosphoprotein phosphatase. ALPase that immunologically cross-reacted with the purified enzyme was found in the extracellular soluble fraction. This means that ALPase is released from the periplasmic space into the culture supernatant as a soluble form.

Alkaline Phosphatase↗
PubMed1990

Learning efficiency of a toothbrush for mastering scrubbing method.

Toothbrushing with long horizontal strokes often causes traumatization of sound enamel and gingival tissues. Also, dental plaque on cervical and adjacent surfaces of teeth can hardly be removed because toothbrush tips cannot reach these regions adequately. A toothbrushing device which indicates overstroke was tested to determine the efficacy with which it makes subjects master brushing with short horizontal strokes following an initial period of instruction. The degree of learning measured in the testing group was superior to that of the control group immediately after the first instruction. Moreover after one week and 12 weeks, its efficacy persisted. The plaque elimination ratio, however, showed no significant difference between the testing group and the control.

Adult↗
PubMed1989

Comparison of recombinant tissue-type plasminogen activator (rt-PA) expressed in mouse C127 cells and human vascular plasminogen activator (HV-PA).

Tissue-type plasminogen activator produced by recombinant DNA technology (rt-PA) has now been recognized as a promising clot-selective thrombolytic agent. We have compared the properties of rt-PA expressed in mouse C127 cells with those of naturally occurring human vascular plasminogen activator (HV-PA). The molecular weight of HV-PA and rt-PA was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to be approx. 66,000. HV-PA and rt-PA were labile and rapidly lost their activities at pH values below 5.5. The optimum pH of HV-PA and rt-PA for plasminogen activation was around 8.5. HV-PA and rt-PA appeared to be very similar in amidolytic properties, amino-acid composition and carbohydrate composition. Moreover, the N-terminal amino-acid sequence of HV-PA was in good agreement with that of rt-PA. The purified preparations of HV-PA and rt-PA had specific activities of about 250,000 and 600,000 IU/mg, respectively. Both activators bound to fibrin clots to similar degree. In immunodiffusion as well as in the quenching experiments of the fibrinolytic activities, rt-PA appeared to be immunodiffusion as well as in the quenching experiments of the fibrinolytic activities, rt-PA appeared to be immunologically indistinguishable from HV-PA. All these findings indicate that rt-PA expressed in mouse C127 cells is identical with naturally occurring HV-PA in physical and chemical properties.

Amino Acid Sequence↗
PubMed1989

Evidence for the presence of two distinct sites of sucrose hydrolysis and glucosyl transfer activities on 1,3-alpha-D-glucan synthase of Streptococcus mutans.

1,3-alpha-D-Glucan synthase of Streptococcus mutans catalyzes both the hydrolysis of sucrose to glucose and fructose, and the glucosyl transfer to glucosyl polymers to yield water-insoluble glucan. The enzyme catalyzes only sucrose hydrolysis, however, in the absence of 1,6-alpha-D-glucan as an acceptor. In the present study, we found that glucosyl transfer activity was completely inhibited by the antiserum against isolated 1,3-alpha-D-glucan synthase but that the sucrose hydrolysis activity was not. The antiserum did not impair the binding of the enzyme to the acceptor. These findings indicate that sucrose hydrolysis and glucosyl transfer occur at two distinct sites on the enzyme.

Binding Sites↗