Biomedical subjects

T Takehara

Publications and source records attributed to T Takehara.

At least 91 records · Page 5Linked to original sources

PubMed1994

Relationship between dental caries experience of a group of Japanese kindergarten children and the results of two caries activity tests conducted on their saliva and dental plaque.

To establish a dental caries preventive programme in 4- and 5-year-old children, caries activity tests were used to assess salivary levels of mutans streptococci (using the Mucount test, Showa Yakuhin, Japan) and the acidogenic ability of dental plaque bacteria (using the Cariostat test, Sankin, Japan) in 260 kindergarten children. The relationships between the results of these two tests and the dental caries experience (dfs) of the children was evaluated. There was a significant positive correlation between the results of the Mucount and Cariostat tests in the total group of subjects. However, 91 subjects (35%) gave conflicting results with the two tests. These subjects were divided into two groups: one group (group B) included Mucount-negative and Cariostat-positive subjects, and the other group (group C) included Mucount-positive and Cariostat-negative subjects. Group B had a significantly higher mean dfs score than a group that was negative on both tests (group A). On the other hand, no significant difference in mean dfs score was observed between group C and group A. These findings suggested that mutans streptococci levels alone are an insufficient indicator for assessing dental caries activity of children at these ages and that the role of lactobacilli and other aciduric bacteria should be considered. It was concluded that assessment of caries activity using both Mucount and Cariostat tests is useful for a dental caries preventive programme for children of these ages.

Child, Preschool↗

PubMed1994

Effective method for discriminating between oral bacterial and human alkaline phosphatase activity.

Alkaline phosphatase (ALPase) activity was quantitatively compared in various kinds of oral bacteria. High ALPase activity was detected in 3 species of periodontal bacteria, Porphyromonas gingivalis, Prevotella intermedia and Capnocytophaga sputigena. The ALPase activity detected in these bacteria was almost completely inhibited in the presence of 1% sodium dodecyl sulfate (SDS). By contrast, the activity of mammalian ALPase isoenzymes was not inhibited at all even in the presence of 1% SDS. These results indicate that the ALPase assay in combination with 1% SDS can identify the origin of ALPase detected in gingival crevicular fluid as being from bacteria or from a host response. Clinical examination with adult periodontitis revealed that ALPase activity in gingival crevicular fluid from the patients consisted of a combination of SDS-sensitive and SDS-resistant activities. These findings indicate that ALPase activity detected in gingival crevicular fluid originates not only from bacteria but also from a host response.

Adult↗

PubMed1994

Effects of hepatitis B virus antigens on interferon-gamma production of peripheral blood mononuclear cells from hepatitis B virus carriers and healthy individuals.

BACKGROUND: Although the precise mechanisms of persistent infection by hepatitis B virus are not yet known, several lines of studies suggest that hepatitis B e antigen in sera might modulate the immune response of the host. The aim of this study was to clarify the effects of hepatitis B virus antigen on cytokine production of lymphocytes. METHODS: We studied the effects of recombinant hepatitis B core antigen and surface antigen on interferon-gamma production of phytohemagglutinin-stimulated peripheral blood mononuclear cells from hepatitis B virus carriers and healthy individuals. Hepatitis B core antigen used in this study shared the antigenic site responsible for hepatitis B core and e antigen. RESULTS: Although pre-incubation of peripheral blood mononuclear cells with hepatitis B core/e antigen followed by stimulation with phytohemagglutinin significantly reduced the production of interferon-gamma, pre-incubation with hepatitis B surface antigen did not affect them. CONCLUSIONS: These results indicate that hepatitis B core/e antigen has the ability to inhibit interferon-gamma production of lectin-stimulated peripheral blood mononuclear cells in vitro, suggesting that secretion of hepatitis B e antigen into sera might be how hepatitis B virus escapes the immuno-surveillance system of the host.

Adult↗

PubMed1994

[Factors related to postoperative hydronephrosis following ureteroneocystostomy in neurogenic bladders].

A total of 68 ureteroneocystostomies performed between 1980 and 1992 in 63 patients with vesicoureteral reflux (UVR) secondary to neurogenic bladder were reviewed to elucidate factors of postoperative hydronephrosis. Urogram, cystogram, and urodynamics were analyzed, and the cases were classified into two types (areflexia, hyperreflexia) of detrusor muscle response. Occurrence or progression of hydronephrosis was demonstrated in 26 operations (complicated group). Compared with the rest (uncomplicated group), significant difference was not observed concerning proportions of vesical deformity, VUR grades, preoperative hydronephrosis, cystometric types and operative factors. In cases of hyperreflexia maximum vesical volume, maximum vesical pressure or maximum urethral pressure was not different between both groups. However, in those of areflexia maximum vesical volume of the complicated group was significantly smaller than that of the uncomplicated group (290 +/- 35 ml vs. 370 +/- 35 ml, P = 0.03), and the proportion of bladders with compliance less than 10 ml/cmH2O was significantly higher in the complicated group than in the uncomplicated group (P = 0.05) though maximum vesical pressure or maximum urethral pressure was not different. In areflex bladder deformity was observed more in the complicated group than in the uncomplicated group (P = 0.06). Relative inactiveness of detrusor muscle in areflex bladder might render such preoperative findings as vesical deformity, contracted bladder and low compliance more prognosticative of postoperative hydronephrosis than in hyperreflex bladder. During the follow up (6 to 132, mean 42 months) no case showed progression of hydronephrosis or renal deterioration, nor did any case require revisional surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Serum hepatitis C virus RNA levels and liver injury in volunteer blood donors.

OBJECTIVES: Liver histology in volunteer blood donors positive for serum hepatitis C virus RNA was investigated in relation to hepatitis C virus viremia levels. METHODS: Twenty-one volunteer blood donors positive for serum hepatitis C virus RNA by polymerase chain reaction were monitored for at least 1 yr by monthly routine liver function tests and underwent liver biopsy. Liver histology findings were correlated with hepatitis C virus viremia levels assessed by a quantitative branched DNA assay. RESULTS: Liver histology showed the features of chronic hepatitis in 20 (95%) patients. Only one of the seven patients with persistently normal aminotransferase levels during follow-up had normal liver histology, and the others had chronic hepatitis. Sera obtained the same day of the liver biopsy were shown to contain hepatitis C virus RNA of 10(5.7)-10(7.6) equivalent/ml (median 10(6.7)). The total histological activity index score (median 2, range 0-15) and the scores of portal inflammation (median 1, range 0-3), lobular inflammation (median 1, range 0-4) and piecemeal necrosis (median 0, range 0-5) correlated with viremia levels (r = 0.64, p < 0.01; r = 0.60, p < 0.01; r = 0.48, p < 0.05; and r = 0.49, p < 0.05, respectively). CONCLUSIONS: These findings suggest that chronic hepatitis is frequently caused by hepatitis C virus infection irrespective of the serum aminotransferase levels, and high level hepatitis C virus replication is a contributory cause for liver injury in volunteer blood donor populations.

Alanine Transaminase↗

PubMed1994

Buoyant density of hepatitis C virus recovered from infected hosts: two different features in sucrose equilibrium density-gradient centrifugation related to degree of liver inflammation.

Hepatitis C virus is reported to have a low buoyant density in sucrose. To determine the density of hepatitis C virus in the circulation of infected hosts and its association with the degree of liver inflammation, we examined serum samples from 10 patients who were positive for both hepatitis C virus antibody (C100 antigen) antibody and serum hepatitis C virus RNA. After the serum was ultracentrifuged in sucrose density gradient (10% to 60%), the hepatitis C virus RNA titer in each collected fraction was quantified by means of competitive reverse transcription-polymerase chain reaction. In samples from five blood donors, the hepatitis C virus RNA titer had a single peak at fractions with densities of 1.08 to 1.11 gm/ml. In samples from five patients with ALT abnormalities, the titer had two peaks at fractions with 1.09 to 1.10 gm/ml and 1.22 to 1.25 gm/ml. After the selected samples were treated with detergents and ultracentrifuged, the titer in the 1.08 to 1.11 gm/ml fractions decreased and that in the 1.22 to 1.25 gm fractions increased. This result implied that the hepatitis C virus density changed with removal of the viral envelope by lipid solvents. Thus the buoyant density of hepatitis C virus in sucrose was 1.08 to 1.11 gm/ml for an intact virion and 1.22 to 1.25 gm/ml for what was presumed to be a nucleocapsid. These results demonstrated that HCV virion is a dominant form in the circulation of blood donors without ALT abnormalities. In patients with liver inflammation HCV particles with higher densities of 1.22 to 1.25 gm/ml coexist with virion in the circulation, which might be presumed nucleocapsids.

Adolescent↗

PubMed1993

Prevalence of hepatitis C virus in family members of patients with hepatitis C.

To investigate the prevalence of hepatitis C virus in the family members of patients with hepatitis C, we examined antibody to hepatitis C virus with a second-generation enzyme-linked immunosorbent assay and viral RNA with a combined assay of reverse transcription and polymerase chain reaction in sera. Among 219 (75 spouses, 110 children, and 34 others), 26 (12%) were antibody positive. The positive rate of antibody to hepatitis C virus was significantly higher than that of the control group (2.0%) and of volunteer blood donors in our district (1.5%), and it increased with age. In particular, the positive rate of antibody to hepatitis C virus among spouses was high (24%). Among family members with elevated ALT, 59% were antibody positive, which was significantly higher than that of the control group (11%). Of the 26 who were antibody positive, 21 (81%) had viral RNA, whereas of the 70 who were antibody negative, only one (1.4%) had viral RNA. These data suggest that hepatitis C virus was transmitted by the infrafamilial route during long duration of contact with patients or sexual transmission. In family members, hepatitis C viral infection is the main cause of liver disorder, and many who were antibody-positive with a second-generation enzyme-linked immunosorbent assay had viremia in the sera.

Adolescent↗

PubMed1993

Effects of cytokines on HLA class I antigen expression on Huh6 and HB611 cells.

This study investigated the expression of HLA class I antigens on Huh6 and HB611 cells induced by interferon (IFN)-alpha, IFN-gamma, tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta. All of these cytokines induced the antigens on both cells in a dose-dependent manner, with IFNs inducing much more expression than TNF-alpha or IL-1 beta. We have already reported that protein kinase C (PKC) is involved in the antigen expression induced by IFN-gamma on Huh6 cells. The antigen expression induced by IFN-alpha was also blocked by a PKC inhibitor, H-7. However, the antigen expression by TNF-alpha or IL-1 beta was not inhibited by H-7, by a protein kinase A inhibitor, HA1004, nor by a calmodulin antagonist, W-7. These results suggested that PKC, Ca(2+)-calmodulin, and cAMP are not involved in the induction of HLA class I antigens on both cells by TNF-alpha and IL-1 beta. We concluded that TNF-alpha and IL-1 beta induced much less expression of HLA class I antigens on both cells than IFNs and that this might be because the signaling pathway by TNF-alpha and IL-1 beta differed from that by IFNs.

Carcinoma, Hepatocellular↗

PubMed1993

Alpha-interferon enhances gamma-interferon production of peripheral blood mononuclear cells pre-activated with phytohemagglutinin.

The question of whether the state of T cell activation is responsible for gamma-interferon production in response to alpha-interferon was determined. When peripheral blood mononuclear cells were pre-incubated with phytohemagglutinin for 3 days, their gamma-interferon production was found to be augmented by alpha-interferon, accompanied by an increased proportion of DR-positive T cells. This did not occur with fresh cells. The effect was dose-dependent and inhibited by anti-alpha-interferon antibody. Therefore, alpha-interferon was considered to enhance the production of gamma-interferon of pre-activated peripheral blood mononuclear cells but not of resting ones. In conclusion, alpha-interferon augmented the production of gamma-interferon of peripheral blood mononuclear cells only when they had already been activated, suggesting a role of alpha-interferon as a modulator of the cellular immune response.

Flow Cytometry↗

PubMed1993

Dental arch and palate in Taiwan aboriginals--Ami, Bunun, Paiwan and Rukai tribes.

Differences in the dental arch and palate among Taiwan Aboriginals were investigated and compared with Taiwanese and Japanese. Plaster models were taken from 315 Taiwan Aboriginal adults, 185 Taiwanese and 426 Japanese between 1979 and 1989, and various dimensions were measured. There were no clear differences in the characteristics of the dental arch and palate between Taiwan Aboriginal tribes. However, they were found to differ from those of Taiwanese and Japanese. In a dendrogram constructed from a cluster analysis, two major clusters were found. Among males, the first cluster contained Paiwan and Rukai, the second contained Japanese, Taiwanese, Ami and Bunun. Among females, the first contained Japanese, Taiwanese, Rukai and Paiwan, the second contained Ami and Bunun. The Ami were close to Bunun and the Paiwan were close to Rukai among both males and females. These results indicate that Ami and Bunun, and Paiwan and Rukai, respectively, have close affinities.

Adult↗

PubMed1993

Quantitative analysis of hepatitis C virus RNA in serum during interferon alfa therapy.

BACKGROUND: Interferon alfa is effective for controlling disease activity in chronic hepatitis C. However, many responders suffer relapse after cessation of therapy. In the present study, the serum concentration of hepatitis C virus RNA was correlated with a sustained response to interferon therapy. METHODS: Fifty-three patients with chronic hepatitis C received a 26-week course of interferon alfa. Hepatitis C virus RNA was quantitated in serum at the beginning and end of treatment using a competitive assay that combined reverse transcription and polymerase chain reaction. RESULTS: In long-term responders, whose alanine aminotransferase levels remained within the normal range during the 24 weeks after therapy, the titer of viral RNA (logarithmic transformed copy numbers per milliliter of serum) before therapy (7.1 +/- 1.2) was significantly lower (P < 0.001) than that of short-term responders (8.3 +/- 0.5) who had a relapse within the 24 weeks after therapy and nonresponders (8.1 +/- 0.4). Multivariate multiple logistic regression showed that the titer of viral RNA before therapy was the strongest independent predictor of a sustained response to interferon-alfa therapy (P = 0.002). CONCLUSIONS: The titer of hepatitis C virus RNA is the most important factor influencing the sustained response to interferon treatment.

2',5'-Oligoadenylate Synthetase↗

PubMed1993

Detection of hepatitis C virus RNA in liver tissues by an in situ hybridization technique.

Hepatitis C virus (HCV) infection of cells in liver tissues was determined by detecting HCV RNA by an in situ hybridization technique using synthetic oligonucleotide probes derived from the 5'-non-coding and core regions of HCV genome. Aggregated silver grains indicating hybridization with HCV RNA were observed over the nuclei as well as the cytoplasm of hepatocytes with none on non-parenchymal cells. The specificity of the hybridization was confirmed by absence of autoradiographic signals after ribonuclease predigestion, addition of an excess of non-labeled probes, or application of an M 13 probe. The hepatocytes with HCV RNA-positive signals were scattered in the periportal and mediolobular zones of liver lobules rather than in the pericentral zones. Fifteen out of 33 biopsy specimens from patients with chronic HCV infection studied had the HCV RNA-positive hepatocytes. These cells were more frequently detected in specimens with advanced periportal, bridging and intralobular necrosis but showed no correlation with the extent of inflammatory cell infiltration. These findings suggest a close correlation between the detection of HCV RNA in hepatocytes and advanced necrosis of the specimens.

Adult↗

PubMed1993

Serodiagnosis of chronic hepatitis C in Japan by second-generation recombinant immunoblot assay.

The seroprevalence of antibodies to hepatitis C virus (HCV) by a second-generation recombinant immunoblot assay (RIBA-2) was tested using 4 recombinant antigens. The results were correlated with those of C100-3 enzyme-linked immunosorbent assay (ELISA) and with the detection of HCV-RNA sequences by the polymerase chain reaction. Sera were obtained from 27 C100-3 ELISA-positive Japanese patients with chronic non-A, non-B liver disease and from 29 C100-3 ELISA-negative patients. All C100-3 ELISA-positive patients and 19 (66%) out of 29 C100-3 ELISA-negative patients reacted to two or more RIBA-2 antigens (reactive by RIBA-2). Of the remaining 10 C100-3 ELISA-negative patients, one patient reacted to just one antigen (indeterminate by RIBA-2), while 9 reacted to none of the 4 antigens (non-reactive by RIBA-2). Forty-three (93%) of the 46 RIBA-2-reactive patients and the single RIBA-2-indeterminate patient tested positive for HCV-RNA sequences, whereas only one (11%) of the 9 RIBA-2-non-reactive patients tested positive. These findings indicate that HCV infection is more prevalent than expected from the results of C100-3 ELISA, and that RIBA-2 is a more sensitive assay for estimating the presence of HCV infection in chronic liver disease.

Aged↗

PubMed1993

Prevalence of malocclusion in high school students in Japan according to the Dental Aesthetic Index.

The Dental Aesthetic Index (DAI) was used to evaluate malocclusion in Japanese high school students (n = 409, ages 15-18 yr). The purpose of this study was to obtain basic data concerning malocclusion in Japanese high school students. This study used a sample of students from randomly selected urban and rural high schools in Japan's Kyushu district. The DAI scores for urban and rural high school students, as well as the total DAI scores from these two areas were significantly higher than that of American high school students. These results showed that the number of students with an acceptable dental appearance among Japanese high school students is significantly lower than among American high school students. This indicates a higher need for orthodontic treatment among Japanese high school students.

Adolescent↗

PubMed1993

Molecular characterization of a STreptococcus mutans mutant altered in environmental stress responses.

A mutant defective in aciduricity, GS5Tn1, was constructed following mutagenesis of Streptococcus mutans GS5 with the conjugative transposon Tn916. The mutant grew poorly at acidic pH levels and was sensitive to high osmolarity and elevated temperatures. These properties resulted from a single insertion of Tn916 into the GS5 chromosome, and the DNA fragment harboring the transposon was isolated into the cosmid vector, charomid 9-20. Spontaneous excision of Tn916 from the cosmid revealed that Tn916 inserted into a 8.6-kb EcoRI fragment. On the basis of the restriction analyses of insert fragments, it was found that Tn916 inserted into a 0.9-kb EcoRI-XbaI fragment. Nucleotide sequence analysis of this fragment indicated the presence of two open reading frames, ORF1 and ORF2. By using a marker rescue strategy, a 6.0-kb HindIII fragment including the target site for Tn916 insertion and the 5' end of ORF1 was isolated and sequenced. The deduced amino acid sequences of ORF1 and ORF2 showed significant homology with the diacylglycerol kinase and Era proteins, respectively, from Escherichia coli. Nucleotide sequence analysis of the Tn916 insertion junction region in the GS5Tn1 chromosome revealed that the transposon inserted near the 3' terminus of ORF1. Restoration of ORF1 to its original sequence in mutant GS5Tn1 was carried out following transformation with integration vector pVA891 containing an intact ORF1. The resultant transformant showed wild-type levels of aciduricity as well as resistance to elevated temperatures and high osmolarity. These results suggest that the S. mutans homolog of diacylglycerol kinase is important for adaptation of the organism to several environmental stress signals.

Amino Acid Sequence↗

PubMed1993

Changes in antibodies to specific hepatitis C virus antigens with interferon-alpha therapy: analysis by recombinant immunoblot assay.

Antibodies to hepatitis C virus NS3 (C33C), NS4 (5-1-1 and C100-3), and core (C22-3) proteins were tested for by a second-generation recombinant immunoblot assay of serum samples from 42 chronic hepatitis C patients treated with interferon-alpha. Antibodies to 5-1-1 and C100-3 were found in 83% (35/42) before therapy, and those to C22-3 and C33C in all patients. At 6 months after therapy withdrawal in patients with sustained virus clearance, only antibodies to 5-1-1 and C100-3 showed significant decreases (p < 0.05) (5/5 and 7/7, respectively). Antibodies to C22-3 and C33C decreased less frequently in only 11% (1/9) (p < 0.01) and 44% (4/9) (p < 0.05), respectively. Thus, antibodies to 5-1-1 and C100-3 are prone to decrease following a decline in viremia. The antibody to the C22-3 (core) protein was least likely to decrease and may serve as a reliable marker of exposure to the virus.

Adult↗

PubMed1993

Quantitative analysis of antibodies to hepatitis C virus during interferon-alpha therapy.

We quantified IgG antibodies to structural (core) and nonstructural (C100-3) hepatitis C virus proteins in 42 patients with chronic hepatitis C treated with a 6-mo course of interferon-alpha. Sera were drawn before and at the end of therapy and also 6 mo after therapy withdrawal; they were stored for later analysis of antibodies and serum hepatitis C virus RNA. Sustained virus clearance was observed at the end of therapy and 6 mo after therapy withdrawal in nine cases; it was accompanied with sustained reductions of antibody to hepatitis C virus core protein and antibody to C100-3 protein. A sustained reduction of antibody to hepatitis C virus core protein was specific to sustained virus clearance, although that of antibody to C100-3 protein was not. None of the patients who did not show reductions of levels of both antibodies at the end of therapy displayed sustained virus clearance. Five patients showed hepatitis C virus RNA negativity and normal aminotransferase levels at the end of therapy without reduction of antibody to hepatitis C virus core protein levels. Of these five patients, relapse of hepatitis occurred in four, and viremia was present 6 mo after therapy withdrawal in all cases. These results demonstrate that testing for antibody titers may add information for evaluating virus clearance after interferon therapy.

Adult↗

PubMed1993

Four different types of glucans synthesised by glucosyltransferases from Streptococcus sobrinus.

Four different kinds of glucosyltransferases (GTFs) were purified from the cariogenic bacterium Streptococcus sobrinus AHT. One of them (GTFP3) produced water-insoluble glucan with the alpha-1,3 linkage, exclusively. The others (GTFP1, P2 and P4) produced water-soluble glucans. GTFP2 produced oligosaccharides with linear 1,6-alpha-D-glucan structure. Since GTFP1 and P4 produce similar molecular weight glucans, the structural differences between these glucans remain unclear. To clarify the difference between GTFP1 and P4 products, the glucan structures were investigated by methylation analysis with gas liquid chromatography and gas liquid chromatography-mass spectrometry. The glucan synthesised by GTFP1 was 1,6-alpha-D-glucan with a high percentage (25.9 mol%) of 1,3-alpha-D-linked units. The other glucan synthesised by GTFP4 contained 1,6-alpha-D-glucan with 1,3,6-alpha-D-glucose (18.5 mol%).

Glucans↗