Search PubMed⌕ Search

Biomedical subjects

T Takehara

Publications and source records attributed to T Takehara.

At least 145 records · Page 8Linked to original sources
PubMed1989

Periodontal disease prevalence in different age groups in Japan as assessed according to the CPITN.

A CPITN survey was conducted involving 12,832 Japanese subjects from 7 to 64 years of age. Subjects under 18 were schoolchildren, and 18-year-old and older subjects represented various social backgrounds, having been randomly selected from both urban and rural Japan. Fifty percent of the 7-yr-old children had signs of periodontal disease, and this percentage increased with increasing age. In those under 14, this increase in periodontal disease was mainly due to an increase in the proportion of children developing dental calculus. Subjects with 6 mm or deeper pockets were observed starting from the 20-29-yr-old age group. In subjects over this age, the prevalence of periodontal disease was higher in men than in women. The percentages of subjects having pathologic pockets had increased remarkably in the 30-44-yr-olds. In the 45-64-yr-old group, almost all subjects had some sign of periodontal disease, and the percentage of those with 4 or 5 mm pockets and 6 mm or deeper pockets were 37% and 21%, respectively.

Adolescent↗
PubMed1989

Purification of a fourth glucosyltransferase from Streptococcus sobrinus.

Recently, we found a novel primer-independent, water-soluble glucan synthase as a fourth glucosyltransferase (GTF) in a culture supernatant of strain AHT-k of Streptococcus sobrinus (Y. Yamashita, N. Hanada, and T. Takehara, Biochem. Biophys. Res. Commun. 150:687-693, 1988). In the present study, four kinds of purified GTFs, including the novel GTF, were prepared. They were composed of two primer-dependent GTFs and two primer-independent GTFs. Of the primer-dependent GTFs, one was a water-insoluble glucan synthase and the other was a water-soluble glucan synthase; both of the primer-independent GTFs were water-soluble glucan synthases (GTF-Sis). Using antisera against four purified GTFs, we concluded that the immunological properties of each were completely different from those of the others. Additionally, it was shown that the novel GTF-Si, which was previously shown to have a molecular weight of 137,000, was proteolytically degraded and could be isolated at a molecular weight of 152,000 and that Streptococcus cricetus secreted an enzyme that immunologically cross-reacted with GTF-Si. While the product of the novel GTF-Si was not an effective primer for both of the primer-dependent enzymes (water-soluble and -insoluble glucan synthases), the product of the enzyme affected the molecular size of the products of the other GTF-Sis.

Chromatography, Affinity↗
PubMed1989

Effect of magnesium ions on secretion of glucosyltransferase from Streptococcus sobrinus.

Magnesium ions, which are known to inhibit the leader peptidase (signal peptidase) activity of Escherichia coli, stimulated the activities of glucosyltransferases (GTFs) in culture medium of Streptococcus sobrinus at concentrations of 1 or 5 mM. At a concentration of 50 mM, the activity of water-soluble glucan synthase was not affected and that of water-insoluble glucan synthase was slightly suppressed. The activities of both GTFs in the crude enzyme extract were totally unaffected by addition of magnesium ions. These findings indicate that magnesium ions have some effects on secretion of the GTFs from S. sobrinus, but that the mechanism of transportation of the enzymes across the plasma membrane in S. sobrinus differs completely from that of proteins secreted into the periplasmic space or assembled in the outer membrane in E. coli.

Culture Media↗
PubMed1989

[Expression of Pre-S2 antigen and antibody in patients with hepatitis B virus infection].

We investigated the expression of Pre-S2 antigen (Ag) and antibody (Ab) in sera quantitatively using ELISA. Four patients with acute hepatitis B and 87 chronic HBV carriers were included in this study. We also investigated the expression of Pre-S2Ag in the liver tissues obtained from 26 chronic HBV carriers by direct fluorescent antibody method. There was a significant correlation between Pre-S2Ag titers and HBsAg titers in sera. Pre-S2Ag titers were higher in sera positive for HBeAg, HBV-related DNA polymerase or HBV-DNA than in sera negative for those markers. The ratio of Pre-S2Ag titers to HBsAg titers, however, was constant irrespective of virus replicative markers. Pre-S2Ag in the liver had almost same intracellular localization with HBsAg in the liver. It was suggested that Pre-S2Ag was expressed with an intimate relation to the expression of HBsAg and was not useful as a virus replicative marker. Pre-S2Ag titers/HBsAg titers tended to be high in patients with chronic active hepatitis and high serum GPT levels compared to patients with chronic inactive hepatitis. This may be explained by the release of Pre-S2Ag in the liver. In addition, all patients positive for Pre-S2Ag on the membrane of hepatocytes had chronic active hepatitis. The overproduction of Pre-S2-containing surface proteins in the liver may have some implication related to cell injury via the immune response to Pre-S2Ag etc. Pre-S2Ab was detected only in few cases of chronic HBV infected patients. The lack of immune response to Pre-S2 region may play a role in the persistence of HBV infection.

Enzyme-Linked Immunosorbent Assay↗
PubMed1989

[Evaluation of changes in portal collaterals by single photon emission CT: effects of endoscopic injection sclerotherapy].

The changes in portal collaterals before and after Endoscopic Injection Sclerotherapy (EIS) for esophageal varices were studied by Single Photon Emission CT (SPECT). SPECT was performed for the intra-abdominal blood pool with 99mTc autologous red blood cells (RBC) in 17 patients with liver cirrhosis before and after EIS. Twenty mCi of 99mTc-RBC labeled by in vivo technique were administered intra-venously and tomographic imaging of the intra-abdominal vascular blood pool was performed as follows. For each subjects, 64 views were obtained over 360 degrees of elliptic rotation at 30 seconds per view. In 15 of 17 patients, blood pool images over coronary vein and/or short gastric vein area were clearly demonstrated on coronary images. In 9 of 15 patients, the pool of coronary vein or short gastric vein was disappeared or decreased after EIS. It is considered that intra-abdominal blood pool SPECT study is clinically useful for following up of hemodynamics of portal collaterals before and after EIS.

Adult↗
PubMed1989

[Expression of pre-S1 antigen and pre-S1 antibody in sera obtained from HBV infected patients].

We investigated the expression of Pre-S1 antigen and Pre-S1 antibody using a synthetic peptide and the monoclonal antibody against it. Four patients with acute hepatitis B and 87 chronic HBsAg carriers were included in this study. There was a significant correlation between Pre-S1 antigen titers and HBsAg titers. Pre-S1 antigen showed higher titers in patients with active viral replication, positive for HBeAg, HBV-DNA or HBV-related DNA polymerase. The ratio of Pre-S1 antigen titers to HBsAg titers, however, had no significant relationship with those replicative markers. It was suggested that Pre-S1 antigen was expressed with an intimate relation to the expression of HBsAg and was not so useful as a new replicative marker. Pre-S1Ag titers/HBsAg titers tended to be high in patients with chronic active hepatitis and high serum GPT levels. This may be due to the release of overproduced intracellular Pre-S1 antigen. Pre-S1 antibody was detected only in few cases of chronic HBsAg carriers. This result shows that the immune tolerance to Pre-S1 region may play a role in the persistence of HBV infection.

Carrier State↗
PubMed1988

A novel glucosyltransferase from Streptococcus mutans produces oligo-isomaltosaccharides.

Streptococcus mutans secretes a sucrose-independent branalphang enzyme that utilizes isomaltosaccharides as donors for branalphang formation on dextran. Although the branching enzyme is necessary for the formation of extracellular polysaccharide complexes, the source of the donor for the enzyme is unknown. In this study, we purified a novel glucosyltransferase from S. mutans and characterized its properties. The glucosyltransferase was primer independent 1,6-alpha-D-glucan synthase, which produced oligo-isomaltosaccharides. The enzyme was thought to be a source of donor for the branching enzyme in S. mutans.

Disaccharides↗
PubMed1988

Immunological properties of the primer-independent glucosyltransferase of Streptococcus mutans serotypes d and g.

Streptococcus mutans serotype g secretes at least three kinds of glucosyltransferase with different enzymological and immunological properties. One of them is a primer-independent enzyme and seems to be the source of primer for the others, both of which are primer-dependent enzymes. Recently, we purified the primer-independent enzyme, the third glucosyltransferase in this group from S. mutans strain AHT-k serotype g. In the present study, we examined the specificity of the antiserum against the primer-independent glucosyltransferase using extracellular culture-conditioned fluids of many strains of the various serotypes of S. mutans. The antiserum cross-reacted with the extracellular culture fluids from strains of serotypes d and a, in addition to serotype g, but not with those of other serotypes, indicating that the primer-independent glucosyltransferase is secreted by the S. sobrinus and S. cricetus, but not by S. mutans and S. rattus. The antiserum did not completely inhibit the activity of the enzyme, even at more than twofold antibody excess, determined by indirect precipitation with immobilized staphylococcal protein A.

Animals↗
PubMed1988

Portosystemic shunting in portal hypertension: evaluation with portal scintigraphy with transrectally administered I-123 IMP.

Portosystemic shunting was evaluated with rectal administration of iodine-123 iodoamphetamine (IMP) in seven patients without liver disease and 53 patients with liver cirrhosis. IMP (2-3 mCi [74-111 MBq]) was administered to the rectum through a catheter. Images of the chest and abdomen were obtained for up to 60 minutes with a scintillation camera interfaced with a computer. In all patients, images of the liver and/or lungs were observed within 5-10 minutes and became clear with time. In patients without liver disease, only liver images could be obtained, whereas the lung was visualized with or without the liver in all patients with liver cirrhosis. The portosystemic shunt index was calculated by dividing counts of lungs by counts of liver and lung. These values were significantly higher in liver cirrhosis, especially in the decompensated stage. Transrectal portal scintigraphy with IMP appears to be a useful method for noninvasive and quantitative evaluation of portosystemic shunting in portal hypertension.

Administration, Rectal↗
PubMed1988

Prevalence and treatment needs of periodontal disease in employees of supermarkets in Japan.

In 1987, a survey was carried out to determine the prevalence and treatment needs of periodontal diseases in 2,684 (997 males and 1,687 females) employees of 57 supermarkets in Japan. The aim of this survey was to obtain fundamental data for planning preventive programs for periodontal diseases in the Japanese population. Most of the subjects showed some signs of periodontal disease. The percentages of persons having pathologic pockets 4 mm or deeper increased with age, and reached about 50% in the 45- to 64-year-olds. The percentage of persons affected was similar between the males and females, but the percentage of persons having pathologic pockets tended to be higher in the males than in the females. These findings indicate that the prevalence of periodontal diseases is extremely high among the Japanese population, and that primary prevention of periodontal disease during school days is required in order to maintain the adults' periodontal health.

Adolescent↗
PubMed1987

Purification and characterization of a third glucosyltransferase from Streptococcus mutans serotype g.

Streptococcus mutans strain AHT (serotype g) secretes at least two glucosyltransferases with different pI values. A novel glucosyltransferase with a pI of 5.8 was purified 244-fold from the ammonium sulphate fraction by DEAE-cellulose chromatography, FPLC (Mono Q column, Pharmacia) and hydrophobic chromatography. The enzyme preparation gave a single protein band on analysis by both PAGE and SDS-PAGE, and did not form multiple protein bands detectable by IEF. The Mr was estimated to be about 130,000 by SDS-PAGE and about 135,000 by ultracentrifugal analysis. The apparent Km value and pH optimum of the enzyme were 3.9 +/- 0.2 mM (mean +/- SD) and about 4.7, respectively. The enzyme synthesized water-soluble glucan from sucrose, and the glucan consisted of over 90 mol% 1,6-alpha-D-glucosidic linkages. The enzyme activity was not stimulated by primer dextran. Anti-enzyme serum produced a single precipitin band with the purified enzyme preparation, whereas it did not react with either of the other two known glucosyltransferases.

Chromatography, DEAE-Cellulose↗
PubMed1985

pH change in artificial dental plaque formed by glucosyltransferase and some oral bacteria during batch and continuous culture.

Streptococcus mutans alone or cell-free glucosyltransferase (G-Tase)-together with either Streptococcus sanguis, Streptococcus salivarius, Actinomyces viscosus, or Lactobacillus casei cells-formed artificial dental plaque that firmly adhered to glass electrodes in a continuous culture system containing sucrose. The pH in these artificial plaque samples decreased more than did that of the surrounding medium. In the absence of GTase, the bacteria other than S. mutans did not form firmly-adhering plaque on glass electrodes. The pH of the plaque formed with GTase alone did not show the pH decrease seen when the plaque contained bacteria, but, because it catalyzed the synthesis of glucan, it is suggested that the glucan acts as a diffusion barrier to retard acid loss from plaque containing acid-producing bacteria.

Actinomyces↗