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Biomedical subjects

T Takehara

Publications and source records attributed to T Takehara.

At least 73 records · Page 4Linked to original sources
PubMed1996

Low expression of erythrocyte complement receptor type 1 in chronic hepatitis C patients.

Primate erythrocyte complement receptor type 1 (CR1) plays an essential role in complement-associated immune complex clearance by transporting complexes to macrophages in the liver and/or spleen. Antibody-bound hepatitis C virus, which consists of immune complexes, is observed in patients with chronic hepatitis C. The aim of this study was to clarify the pathophysiological roles of erythrocyte CR1 in hepatitis C virus-infected individuals. We quantified the expression of erythrocyte CR1 with a fluorescence-activated cell sorter system in 57 chronic hepatitis C and 37 chronic hepatitis B cases and 20 normal volunteers. Complement-bound immune complexes were quantified by means of an enzyme-linked immunosorbent assay using anti-C1q and anti-C3d antibodies. Hepatitis C virus-infected patients showed lower erythrocyte CR1 and higher C3d immune complex levels than volunteers (P < 0.01 and P < 0.05, respectively). An inverse correlation was observed between the erythrocyte CR1 and C3d immune complex levels in hepatitis C virus infection (r = -0.300, P = 0.032). The erythrocyte CR1 levels in hepatitis C virus infection were lower in patients with severe liver inflammation, cirrhosis, or hepatocellular carcinoma than in those with mild inflammation, whereas the levels did not differ regardless of the disease stage in hepatitis B virus infection. These findings demonstrate that the expression of erythrocyte CR1 is related to immune complex quantity and the severity of liver disease in hepatitis C virus infection.

Adult↗
PubMed1996

Transblot identification of avidin-interacting proteins in rat salivary glands.

Blotting of rat parotid gland proteins separated by SDS-PAGE and transferred to Immobilon transfer membranes revealed that avidin-peroxidase conjugate interacted with bands having estimated molecular weights of 72, 74, and 120 kDa. Even at the lowest concentration of avidin-peroxidase used in the general ABC method (1:2000 dilution), three bands were clearly discernible. The staining reaction of parotid gland proteins was eliminated on preincubating the proteins with native avidin. The staining reaction was markedly reduced with the proteins obtained from submandibular/sublingual glands.

Animals↗
PubMed1996

Immunogenicity of Actinobacillus actinomycetemcomitans serotype b-specific polysaccharide-protein conjugate.

To enhance the immunogenicity of capsular-like serotype b-specific polysaccharide antigen (SPA) of Actinobacillus actinomycetemcomitans, the purified antigen was coupled with bovine serum albumin via an adipic acid hydrazide functional group. The conjugate (SPA-bovine serum albumin) or the native SPA was administered subcutaneously or intranasally to BALB/c mice. Neither subcutaneous immunization with SPA emulsified in Freund adjuvant nor intranasal immunization with SPA and cholera toxin B subunit elicited any antibody responses to the polysaccharide antigen. High serum immunoglobulin M (IgM) and IgG responses to SPA were induced by subcutaneous immunization with SPA-bovine serum albumin in Freund adjuvant. Serum and salivary IgA responses to SPA in addition to IgM and IgG responses were induced by intranasal immunization with the conjugate and cholera toxin B subunit. To investigate the functional activity of SPA-specific antibodies, the opsonic activity of sera from BALB/c mice immunized with the conjugate was assessed by chemiluminescence assay using human polymorphonuclear leukocytes. Murine antisera efficiently opsonized A. actinomycetemcomitans serotype b in the assay, suggesting that antibodies to SPA of the organism might serve as a protective role.

Aggregatibacter actinomycetemcomitans↗
PubMed1995

Serial density analysis of hepatitis C virus particle populations in chronic hepatitis C patients treated with interferon-alpha.

In interferon treatment of chronic hepatitis C patients, the biochemical and virological responses mostly parallel each other. However, some patients who show persistent ALT normalization display continued viremia after cessation of therapy. High-density hepatitis C virus (HCV) particles, which are immune complex forms, are reported to be less infectious both in vitro and in vivo. To assess whether high-density HCV contributes to the response discrepancies and to clarify the association with patient outcome, sera were examined from chronic hepatitis C patients who were treated with interferon-alpha. This study included 10 sustained responders with viremia (SR + ve), 5 SR without viremia, 3 transient responders (TR), and 3 nonresponders (NR). The SR + ve patients were defined as those with continued ALT normalization and serum HCV-RNA positivity at 24 weeks after therapy completion. Serum samples obtained before and 24 weeks after therapy were ultracentrifuged on 35% sucrose. The ratio between high-density and low-density HCV was determined by quantification of HCV-RNA titers in the bottom and top fractions by competitive reverse transcription and by the polymerase chain reaction, and expressed as the bottom/top (B/T) ratio. The B/T ratios before therapy were 1:1 in all groups of patients, and 1:1 after therapy in TR and NR groups. Five out of 6 SR + ve patients who showed 1:1 ratio after therapy relapsed within 1 year. In contrast, all SR + ve patients whose ratios were 10-100:1 continued to show ALT normalization. These findings demonstrate that patients who have high-density HCV dominance after therapy show persistent ALT normalization despite viremia, which can be explained by predominance of the neutralized immune complex.

Adult↗
PubMed1995

Tumor necrosis factor-alpha and interferon-gamma inhibit synergistically viral replication in hepatitis B virus-replicating cells.

The effects of tumor necrosis factor-alpha and/or interferon-gamma on the replication of hepatitis B virus were examined using HB611 cells. These cells were derived from human hepatoblastoma cells, Huh6, by integrating hepatitis B virus DNA, and produce hepatitis B virus continuously. Each of the cytokines inhibited hepatitis B virus replication in the cells assessed as the amount of episomal hepatitis B virus DNA, without a decrease in cell viability. When the two cytokines were administered together, the inhibitory effect became greater. Incubation of the cells with 1,000 U/ml tumor necrosis factor-alpha decreased HBV DNA replicative intermediates by 55%, and that with 1,000 U/ml interferon-gamma decreased these by 51%. Furthermore, incubation with 1,000 U/ml tumor necrosis factor-alpha and 1,000 U/ml interferon-gamma in combination decreased HBV DNA replicative intermediates by 71%. In contrast, the amount of hepatitis B virus RNA and secretion of hepatitis B e antigen were not apparently reduced by the cytokines, and 2',5'-oligoadenylate synthetase activity was not detected in the supernatant. These results suggest that tumor necrosis factor-alpha and interferon-gamma inhibit hepatitis B virus replication by blocking some step in reverse transcription and that the 2',5'-oligoadenylate synthetase is not involved in the mechanism underlying the inhibition by these two cytokines.

2',5'-Oligoadenylate Synthetase↗
PubMed1995

Density analysis of hepatitis C virus particle population in the circulation of infected hosts: implications for virus neutralization or persistence.

Hepatitis C virus has a low buoyant density in sucrose, but high-density particles are often observed in hepatitis C virus infection. To investigate the characteristics of circulating hepatitis C virus particles and their association with liver disease progression, we examined sera from two histologically normal hepatitis C virus carriers, 20 chronic hepatitis patients and five acute hepatitis C patients. The supernatants obtained after immunoprecipitation with anti-immunoglobulins antibody were subjected to sucrose equilibrium centrifugation. HCV-RNA positive fractions separated after the treatments were further examined for immunoprecipitation with anti-core hepatitis C virus antibody. We separated hepatitis C virus particle populations according to the density difference on 35% sucrose with centrifugation. The proportions of high and low density particles in hepatitis C virus populations were determined by means of competitive reverse transcription and polymerase chain reaction. Circulating hepatitis C virus particles in chronically infected patients could be separated into two populations: those immunoglobulin-bound with high densities and -unbound with low densities. Patients with severe liver inflammation had high-density hepatitis C virus that did not precipitate with anti-immunoglobulins but with anti-core hepatitis C virus antibodies. Thus, hepatitis C virus particle populations consist of low-density virions and high-density immune complexes and/or nucleocapsids. Among the chronic hepatitis patients, the dominant population shifted from low-density to high-density particles with the progression of liver disease. In acute hepatitis patients, this density shift was observed with alanine aminotransferase normalizations. Therefore, the major hepatitis C virus populations change from virion to immune complex and/or nucleocapsid with the progression of liver disease or inflammation.

Acute Disease↗
PubMed1995

Pretreatment viral load and response to prolonged interferon-alpha course for chronic hepatitis C.

BACKGROUND/AIMS: We investigated the clinical benefit of long-term interferon therapy in chronic hepatitis C in relation to the pretreatment viral load and genotypes. METHODS: Chronic hepatitis C patients were randomly assigned to receive 28-week (n = 45) or 52-week (n = 43) courses of interferon-alpha. The responses were correlated with pretreatment viremic levels assessed by a branched DNA assay and genotypes. RESULTS: After the 28-week interferon-alpha course, sustained aminotransferase normalization showed correlation with a lower initial viral load. The normalization was achieved by 78% (7/9) of the low viremic (branched DNA-negative) patients, but only 22% (8/36) of the highly viremic (branched DNA-positive) patients (p < 0.01). Treatment with the 52-week interferon-alpha course increased the incidence of a sustained response in highly viremic patients and led to a decrease in relapse after therapy withdrawal (p < 0.05). Thus, 75% (6/8) of the low viremic patients and 49% (17/35) of the highly viremic patients showed a sustained response. The data further showed that frequent sustained responses in patients with genotypes III and IV were associated with a low initial viral load. CONCLUSIONS: These findings suggest that although the pretreatment viral load is an important virological factor for predicting responses to interferon in chronic hepatitis C, relapse in highly viremic patients may be prevented by long-term therapy.

Adult↗
PubMed1995

Improvement of liver fibrosis in chronic hepatitis C patients treated with natural interferon alpha.

To investigate the histological change (change of liver fibrosis) produced by the anti-viral effect of interferon on hepatitis C virus, 40 patients with chronic hepatitis C treated with natural interferon alpha were divided according to the existence of viremia at the end of treatment and 6 months after the end of treatment. The condition of liver fibrosis was scored numerically with a new "hepatic fibrosis score" which is sensitive to more subtle changes than Knodell's fibrosis score. Each portal zone was evaluated separately. End-of-treatment biopsy for the HCV RNA-negative group (negative for HCV RNA at the end of treatment) showed a significant improvement of the "hepatic fibrosis score" as well as the alleviation of necrosis and inflammation. At the end of treatment and 6 months after that, serum procollagen type III peptide levels and serum type IV collagen-7s levels had also decreased significantly in the HCV RNA-negative group. The present study showed that treatment with interferon alpha could alleviate fibrosis in addition to necrosis and inflammation.

Adult↗
PubMed1995

A murC gene in Porphyromonas gingivalis 381.

The gene encoding a 51 kDa polypeptide of Porphyromonas gingivalis 381 was isolated by immunoblotting using an antiserum raised against P. gingivalis alkaline phosphatase. DNA sequence analysis of a 2.5 kb DNA fragment containing a gene encoding the 51 kDa protein revealed one complete and two incomplete ORFs. Database searches using the FASTA program revealed significant homology between the P. gingivalis 51 kDa protein and the MurC protein of Escherichia coli, which functions in peptidoglycan synthesis. The cloned 51 kDa protein encoded a functional product that complemented an E. coli murC mutant. Moreover, the ORF just upstream of murC coded for a protein that was 31% homologous with the E. coli MurG protein. The ORF just downstream of murC coded for a protein that was 17% homologous with the Streptococcus pneumoniae penicillin-binding protein 2B (PBP2B), which functions in peptidoglycan synthesis and is responsible for antibiotic resistance. These results suggest that P. gingivalis contains a homologue of the E. coli peptidoglycan synthesis gene murC and indicate the possibility of a cluster of genes responsible for cell division and cell growth, as in the E. coli mra region.

Alkaline Phosphatase↗
PubMed1995

Correlation between volatile sulphur compounds and certain oral health measurements in the general population.

Oral malodor was measured using a portable sulphide monitor in 2,672 individuals aged 18 to 64 years. In addition, dental (DMFT) and periodontal conditions (CPITN and attachment loss), dental plaque, and tongue coating status were assessed. Before clinical examination, subjects were interviewed about their oral health habits, smoking habits, and medical history. Data on volatile sulphur compounds (VSC) were analyzed by gender, age group, and time of measurement. There were no significant differences observed in the VSC between males and females in any age group. In each age group, the measured values of oral malodor were highest in the late morning group (58.6 ppb in average), followed by the late afternoon group (52.1 ppb), while lowest values were shown in the early afternoon group (39.4 ppb). Significant correlation was observed only between the VSC value and periodontal conditions and tongue coating status. The results also suggest that oral malodor might be caused mainly by tongue coating in the younger generation and by periodontal diseases together with tongue coating in older cohorts in the general population. Age was not a risk factor for increasing VSC.

Adolescent↗
PubMed1995

In vivo transfection of hepatitis C virus complementary DNA into rodent liver by asialoglycoprotein receptor mediated gene delivery.

An in vivo model of hepatitis C virus (HCV) infection is needed to enable investigation of the mechanism of the liver injury that it causes. In this study, we used asialoglycoprotein receptor mediated gene delivery to obtain expression of the complementary DNA (cDNA) coding the core and part of the envelope 1 protein of HCV because selective delivery to the hepatocytes has been reported to be attained with this method. The optimum carrier-DNA ratio was examined using in vitro transfection and found to be important for the efficiency of this method. In transfection in vivo, microautoradiographical examination showed that the transfected plasmids were delivered selectively to the liver parenchymal cells. To obtain an immunohistochemically detectable level of protein expression in rodent liver, some modifications for increasing the in vivo transfection efficiency were performed; a lysosomal enzyme inhibitor, chloroquine, was used and the administration route of the carrier-DNA complex was changed from the tail vein to the portal vein. On the bases of these results, in vivo transfection with expression vector of HCV core/E1 region was performed. In rat liver transfected by intraportal injection with chloroquine, the transcript RNA and the core protein were detected. These results indicated that the HCV core/E1 expression vector was not merely delivered but also successfully expressed in the liver using asialoglycoprotein receptor mediated gene delivery. The number of the HCV core expressing cells in the transfected liver was similar to that in patients with hepatitis C. These in vivo transfected animals should be useful for investigating the role of this region in the liver injury caused by HCV.

Animals↗
PubMed1995

Protein phosphatase inhibitors, okadaic acid and calyculin A, induce alkaline phosphatase activity in osteoblastic cells derived from newborn mouse calvaria.

To determine whether protein phosphatases can affect bone regulation, we examined the effects of okadaic acid (OA) and calyculin A (CA), specific inhibitors of protein phosphatases type 1 and type 2A, on alkaline phosphatase activity of mouse osteoblastic cells. Clone MC3T3-E1 cells were cultured with varying concentrations of OA and CA. OA and CA stimulated alkaline phosphatase (ALP) activity in the cells in dose-dependent fashion with a maximal effect at concentrations of 5 nM and 2 nM, respectively. The properties of OA-induced and native ALP in the cells were the same and they were liver-bone-kidney type. These results show that protein phosphatase inhibitors stimulate bone formation in vitro and that phosphorylation and dephosphorylation of specific proteins in the cells may be involved in bone regulation in vivo as well.

Alkaline Phosphatase↗
PubMed1995

Expression of the hepatitis C virus genome in rat liver after cationic liposome-mediated in vivo gene transfer.

The lack of a small animal model of hepatitis C virus (HCV) infection has impeded elucidation of the pathogenesis of HCV. The aim of this study was to develop an HCV-expressing animal model by means of cationic liposome-mediated in vivo gene transfer. To examine the feasibility of this strategy, pActLacZ, an expression vector composed of the LacZ gene driven by the beta-actin promoter, complexed with lipofectin, was injected retrogradely into the common bile ducts of adult rats. X-Gal histochemical staining clearly showed that the LacZ gene was expressed in hepatocytes, but not in biliary epithelial cells. Maximal expression was observed at a DNA to lipofectin ratio of 1:4. Based on this observation, pAGS3M091, an expression vector containing the full length of HCV complementary DNA (cDNA) preceded by the beta-actin promoter, was evaluated. Two days after in vivo intrabiliary administration of pAGS3M091 complexed with lipofectin, polymerase chain reaction (PCR) amplification of reverse-transcribed liver RNA demonstrated the 5' and 3' portions of HCV transcripts derived from pAGS3M091. Immunohistochemical analysis showed the HCV core protein in a small number of hepatocytes scattered in the hepatic lobules. We conclude that the full-length HCV genome was successfully expressed in adult rat liver by means of cationic liposome-mediated in vivo gene transfer. This model will be useful for determining the immunopathological role of HCV in vivo.

Animals↗
PubMed1995

Periodontal conditions in older age cohorts aged 65 years and older in Japan, measured by CPITN and loss of attachment.

Periodontal conditions were assessed by CPITN and loss of attachment in 601 elderly people randomly selected in Kitakyushu, Japan. The percentage of edentulous persons was 21 per cent, 38 per cent and 65 per cent in the 65-74 year, 75-84 year and 85 years and older groups, respectively. In dentate persons, over 60 per cent had pocket probing depths of 4mm or more; in the majority loss of attachment did not exceed 5mm. The mean numbers of sextants with pocket probing depths of 4-5mm (CPITN 3) and probing depths of 6mm and more (CPITN 4) were similar in each age group. The mean numbers of sextants with both pockets and loss of attachment showed no clear difference among groups. Only the mean number of excluded (no, or only one tooth) sextants increased with increasing age from 1.9 to 3.1. It could therefore be suggested that in the population examined the progress of periodontal destruction with increasing age might not be shown by an increase in pocket probing depth, loss of attachment or gingival recession, but only by an increase in tooth loss. The results for the remaining teeth show that a) severe loss of periodontal attachment (6mm or more) was not frequently encountered, b) recession (attachment loss without pocketing) was present at only very low levels, c) the main periodontal problem seemed to be pocketing, which could be treated. It is therefore tempting to suggest that some of the teeth already lost, could have been saved if proper self- and professional care had been applied.

Aged↗
PubMed1995

In vivo transfection of rat liver with hepatitis C virus cDNA using cationic liposome-mediated gene delivery.

The lack of a small animal model for hepatitis C virus (HCV) infection has impeded elucidation of the pathogenesis of this virus. The aim of this study was to develop an HCV-expressing animal model using cationic liposome-mediated in vivo gene transfer. To examine the feasibility of this strategy, an expression vector composed of the LacZ gene driven by the beta-actin promoter, pActLacZ, was injected retrogradely into the common bile ducts of adult rats. X-Gal histochemical staining clearly showed that the LacZ gene was expressed in hepatocytes. Maximal expression was observed at a DNA:lipofectin ratio of 1:4. Based on this observation, an expression vector containing the full-length of HCV cDNA, pAGS3M091, was evaluated in adult rats. Two days after intrabiliary administration of pAGS3M091, PCR amplification of reverse-transcribed liver RNA demonstrated the 5' and 3' portions of HCV transcripts derived from pAGS3M091. Immunohistochemical analysis revealed the HCV core protein in a small number of hepatocytes scattered in the lobules. Thus, the full-length of the HCV genome was successfully expressed in adult rat liver using liposome-mediated in vivo gene transfer.

Animals↗
PubMed1994

Role of Fas ligand in apoptosis induced by hepatitis C virus infection.

To investigate the role that Fas ligand plays in the apoptosis of hepatocytes induced by hepatitis C virus infection, we isolated a cDNA clone for human Fas ligand and examined the expression of Fas ligand in liver-infiltrating mononuclear cells obtained from patients with chronic hepatitis C. The amino acid sequence of human Fas ligand showed 76% and 77% identity with those of rat and mouse Fas ligand, respectively. When the expression of Fas ligand transcripts was tested by reverse transcription-polymerase chain reaction, the amplified signal was detected in liver-infiltrating mononuclear cells and peripheral blood mononuclear cells, whereas only a weak signal or none at all was detected in liver tissues. These findings suggest that the Fas ligand-Fas antigen system may play an important role in liver cell injury by hepatitis C virus infection.

Amino Acid Sequence↗
PubMed1994

Selective intrathecal phenol block to improve activities of daily living in patients with spastic quadriplegia. A preliminary report.

To eliminate severe leg spasms of 15 quadriplegics, 0.3 ml 10% phenol-glycerin was injected into the subarachnoid space at the T12/L1 interspace. The effectiveness for leg spasm was evaluated by the Penn spasticity and Ashworth rigidity scales. Three patients remained completely flaccid; however three had slight, six had moderate and three had complete recurrence of spasms in a follow up period of observation for 1 to 22 (average 13) months. The result of selective intrathecal phenol block was significantly valuable, improving the activities of daily living (ADL) of quadriplegic patients. There were no systemic side effects nor disturbance of bladder, bowel or sexual functions.

Activities of Daily Living↗