Biomedical subjects

M Mizokami

Publications and source records attributed to M Mizokami.

At least 163 records · Page 9Linked to original sources

PubMed1994

[Significance of serological genotyping of hepatitis C virus in Japanese patients with chronic liver disease due to hepatitis C].

Recently, T-Kohara et al. reported that most hepatitis C virus (HCV) in Japan can be classified into two groups, group 1 (G-1) and group 2 (G-2), on the basis of the NS4 region nucleotide sequence. Using a genetic engineering method, they developed a new assay in which antibodies against group specific recombinant proteins of the NS4 region were measured by ELISA (Serological Genotype, Serotype). In the present study, we examined 100 patients with chronic liver disease due to hepatitis C. The sensitivity of this assay was 98.0% (98/100). The HCV serotype distribution was 74/100 (74.0%) for serotype G-1, 22/100 (22.0%) for serotype G-2, 2/100 (2.0%) for both being positive and 2/100 (2.0%) for indeterminate. The distribution of G-1 was significantly higher than that of G-2 (p < 0.05), however, we found no difference between the distribution of G-1 and that of G-2 in age, sex, history of blood transfusion or type of liver disease. In the same serum samples, we performed HCV genotyping by reverse transcription polymerase chain reaction (RT-PCR) using type specific primers derived from the NS5 region of HCV to verify the specificity of such serotyping. The sensitivity of genotyping by RT-PCR was 88.0% (88/100). The HCV genotypes determined by both methods were consistent in 86.0% (86/100) of cases, and were not contradictory in any sample. These data indicated that serological genotyping was more sensitive and was consistent with genotyping by RT-PCR. Therefore, we consider the method useful for epidemiologic studies of HCV in Japan.

Adult↗

PubMed1994

[Relation between HCV genotype and serum HCV RNA level as predictors of response to interferon-alfa 2b therapy in chronic hepatitis C].

It has been reported that pre-treatment serum HCV RNA levels was important predicting factors to subsequent interferon therapy (Orito et al.). In this report, HCV genotype and serum HCV RNA level were determined using PCR and bDNA assay in patients who received interferon-alfa 2b. Patients with genotype III HCV responded more favorably in complete and sustained response than genotype II HCV. A higher proportion of patients who had low pre-treatment serum HCV RNA level responded in complete and sustained fashion. When patients with high or low level viremia were compared, significantly higher proportion of the patients with low level HCV RNA showed sustained response irrespective of HCV genotype.

Adult↗

PubMed1993

Discrepancy between biochemical and virological responses to interferon-alpha in chronic hepatitis C.

Serial serum samples and pretreatment and post-treatment liver tissue from patients with chronic hepatitis C virus (HCV) infection were tested for HCV RNA by reverse-transcription polymerase chain reaction and branched DNA signal amplification assays. At the end of treatment with interferon-alpha (IFN alpha), 4 of 5 patients showing no biochemical response (in alanine aminotransferase activity), 4 of 5 with transient responses, and 1 of 5 showing complete and sustained responses had HCV RNA detectable in serum. The corresponding numbers for liver tissue were 5, 5, and 0 (of 4). However, all 5 complete responders had virological relapses within 6 months. Biochemical response may not reflect virological profile during IFN alpha treatment of HCV.

Adult↗

PubMed1993

Significance of serum hepatitis C virus RNA levels in chronic hepatitis C.

Hepatitis C virus (HCV) is the main cause of parenteral non-A, non-B hepatitis and serum can be tested for the virus itself by reverse-transcription polymerase chain amplification. What of the level of this viraemia? To find out if quantitative study of HCV RNA might be useful clinically we took advantage of participation in trials of interferon-alpha in patients with chronic HCV infection and applied a new assay, branched DNA (bDNA) signal amplification. Paired serum and liver biopsy specimens from 47 patients with confirmed chronic HCV infection and evidence of HCV RNA in their serum were studied. The quantitative bDNA assay (detection limit 350,000 equivalents/mL [eq/mL]) was positive in 34 sera (sensitivity 72%). Patients who acquired HCV infection by blood transfusion had a higher viraemia (median 2,701,000 eq/mL, n = 29) than health workers and intravenous drug users (635,000 eq/mL, n = 13; p < 0.01). Patients with a sustained complete response to interferon-alpha therapy had lower pre-treatment viraemia levels (median at bDNA cut-off, n = 11) than complete responders who relapsed after the drug was stopped (1,613,000 eq/mL, n = 15; p < 0.01) and non-responders (3,066,000 eq/mL, n = 20; p < 0.01). High viraemia levels were not related to the histological diagnosis but were associated with lobular inflammation, lymphoid aggregates, and bile-duct lesions. These findings indicate that mode of acquisition is an important determinant of HCV viraemia and that patients with low HCV viraemia levels are more likely to respond to interferon in a sustained fashion.

Adult↗

PubMed1993

Antigenicities of Group I and II hepatitis C virus polypeptides--molecular basis of diagnosis.

Comparative nucleotide sequence studies on the putative NS3 and NS4 regions of the genomes of hepatitis C viruses (HCV) have revealed that there are at least two groups of HCV, group I and group II. The cDNA clone E, corresponding to a boundary between the NS3 and NS4 (NS3-4) region of the group II HCV genome, encodes antigens that react to antibodies specific to group II HCV (Tsukiyama-Kohara et al. (1991) Virus Genes 5, 243-254). To understand the molecular basis of the group-specific antigenicity of HCV peptides, the predicted amino acid sequences around the NS3-4 region of our group II HCV cDNAs were compared with those of other HCV isolates. The analysis revealed the presence of group-specific amino acids in this peptide region. Evolutionary analysis of nucleotide sequences within this region of these HCV isolates also led to the same classification. A similar result was obtained by sequence analysis of cloned cDNAs corresponding to the core region. A cDNA of the group II HCV core region was prepared by polymerase chain reaction from the cDNA synthesized with group II-specific primer complementary to the NS3-4 region. The products directed by the cDNA of the core region did not have group-specific antigenicity. The NS3 peptide region also appeared not to carry group-specific antigens. Our results indicate that most HCV isolates can be classified into either group I or II, and that the existence of two groups of HCV does not disturb HCV diagnosis as long as core and/or NS3 peptides are used to detect HCV antibodies.

Amino Acid Sequence↗

PubMed1993

Dynamics of genome change in the E2/NS1 region of hepatitis C virus in vivo.

To substantiate and extend the quasispecies model of hepatitis C virus (HCV), we made a pairwise comparison in the nucleotide and deduced amino acid sequences for multiple recombinant clones of the E2/NS1 region, which derived from each blood sample taken from five patients of subtype II or subtype III infection at different stages. Sequence heterogeneity among the clones was generally high. The heterogeneity, however, changed temporally and appeared to be significantly lowered after interferon therapy. The temporal fluctuation involved selection of particular amino acids at particular positions, which had represented only a minor fraction or had been absent in the previous clones. Evolution of defective viruses was featured by most of the cases, the proportion of which also fluctuated temporally and was extremely high at a certain stage in one of the patients. A comparison was also made among the clones from different stages of each patient and revealed highly divergent clones. An extreme case of subtype III infection showed sequence differences well beyond those among chronologically and geographically different isolates of subtype I or subtype II, which were defined by the same calculation of available sequence data. These features of HCV genome suggest that the virus could circulate as an extremely heterogeneous population including defective viruses and that this heterogeneity lends itself to selection pressures including interferon therapy and host immune response. Our results also indicate an absolute need of population based approach in HCV genetics.

Aged↗

PubMed1993

Molecular classification of hepatitis C virus.

Many sequences of hepatitis C virus (HCV) have been reported, but there has been no report about the evolutionary classification of HCV. The aim of this study is to classify the nucleotide sequences of HCV into appropriate genetical groups by molecular evolutionary methods. A number of nucleotide sequences of HCV were collected from all over the world. First, all HCV nucleotide sequences for each region were aligned to optimize homologies. Phylogenetic trees were then constructed for each region of HCV according to the number of the nucleotide substitutions. HCVs can be classified into two or three major groups in the trees of each regions. However, minor groups can be classified into two in that of 5' non-coding, four in that of Core, Env., E2/NS1, NS3 and NS4 region and six in that of NS5 region. However, the full sequences such as HCV-1, HCVH and HCV-J4, were always located in the same major and minor groups in that trees of all regions. These data indicated that HCVs can be classified into two or three major and six minor groups.

Base Sequence↗

PubMed1993

Significance of antibody to the host cellular gene derived epitope GOR in chronic hepatitis C virus infection.

The humoral response to the host cellular gene-derived epitope GOR (anti-GOR) was reported to be associated with chronic hepatitis C virus (HCV) infection. To determine the prevalence and clinical significance of anti-GOR, sera from 31 patients (M/F, 19/12, age 30-72) with chronic HCV infection (anti-HCV+ in 30, HCV-RNA+ by PCR in 31) were tested for anti-GOR by enzyme immunoassay. Results were correlated with clinical, biochemical and histological features, and the subsequent response to interferon-alpha therapy (a complete response was defined as normalization of serum ALT at the completion of therapy; a sustained response was defined as having normal serum liver biochemistry during the entire follow-up period). Anti-GOR was detected in 21 patients [67.7%, median optical density (OD) reading 2.634, range 0.865-3.000, cut-off value 0.300]. There was no correlation between the presence or the OD reading of anti-GOR and the clinical features (sex, age, mode of acquisition), biochemical tests (serum ALT, AST, alkaline phosphatase and albumin levels), autoimmune markers [serum globulin levels, anti-nuclear antibody (+ at < 1:80 in 6/31 patients)], and their subsequent response to interferon-alpha therapy (complete response in anti-GOR+ patients: 13/21, anti-GOR-: 5/10, p = NS; sustained response in anti-GOR+ patients: 5/21, anti-GOR-: 2/10, p = NS). There was also no correlation between anti-GOR and the histological features including Knodell score and its components including periportal inflammation, portal inflammation and fibrosis, the presence of lymphoid aggregates, macrovesicular and microvesicular fat, multinucleated hepatocytes, dysplasia, sinusoidal activity or bile duct lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[Molecular genotypes of hepatitis C virus and their divergence times].

We collected the nucleotide sequences of hepatitis C virus (HCV) from the international DNA data base DDBJ/EMBL/GenBank to carry out molecular evolutionary analysis of HCVs. Using these sequences, we constructed the phylogenetic trees for the 5' non-coding, Core, Env., E2/NS1, NS3, NS4 and NS5 regions of HCV. The number of nucleotide substitutions per site at all positions between all pairs of HCVs, for each region, were estimated by the 6-parameter method. Using these numbers, we constructed phylogenetic trees for each region of HCV by the neighbor-joining method. In these trees for the coding regions (Core, Env, E2/NS1, NS3, NS4 and NS5 regions), HCVs can be classified into two major and four minor genotypes, but into three major and six minor genotypes on the tree of the NS5 region. It appears that HCVs exist as at least two or three major and six minor types. The evolutionary rates of HCV was estimated to be about 10(-3) per site per year close to that of human immunodeficiency virus. The new genotypes of HCV may be therefore isolated elsewhere in the near future. Then, applying the distance between H77 and H90 strains to the phylogenetic trees, we estimated the divergence times of HCVs. The major genotypes diverged about 300-400 years ago from the ancestor virus and after then, each minor genotypes diversed about 200 years ago from their major genotypes. These data suggested that HCVs spread out all over the world during these hundred years.

Base Sequence↗

PubMed1993

[Molecular evolutionary analysis of hepatitis B virus (HBV) and genetic classification].

HBsAg of Hepatitis B virus (HBV) has been classified into four major subtypes (adw, adr, ayw, ayr) by the serological methods. Using molecular evolutionary analysis technique, we constructed the phylogenetic tree for the partial S gene (HBsAg gene) of HBV. The tree shows that 51 strains of HBV can be classified into following four genetic subgroups: (1) strains of subtypes ayw and adyw, (2) those of adw and adr, (3) another of adw, and (4) other subgroup of adr, adw, ayr, ar and ad. We propose that these subgroups be designated gyw, gdw-1, gdw-2, and gdr, respectively, with "g" standing for genetic classification. It is important that the genetic classification of HBVs is not always compatible with conventional serological subtypes. It is possible that the conventional subtypes do not represent a classification according to the degree of genetic difference among strains of HBVs. Thus, our genetic classification is more suitable for studies of epidemiological and virological features of HBVs.

Amino Acid Sequence↗

PubMed1993

[Defective short variants of S region in chronic HBV carriers].

We analyzed the pre-S and S region of hepatitis B virus by polymerase chain reaction in 60 chronic carriers. In 10 hepatitis B e antigen-positive chronic carriers, a single DNA band was detected at the expected size, whereas additional shorter DNA bands were observed in some cases with chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The smaller-sized DNA bands from chronic hepatitis patients had the deletion of 183 bp in the pre-S gene, and the deletion of 492 bp in S gene. The reasons of the appearance of these mutants are unknown, but it may be interesting to study in relationship to the mechanism of host immune response.

Adult↗

PubMed1992

Polymerase chain reaction assay for hepatitis C virus RNA using a single tube for reverse transcription and serial rounds of amplification with nested primer pairs.

A procedure is described for the detection of hepatitis C virus (HCV) RNA in blood by means of the polymerase chain reaction (PCR) in which the reverse transcription step and two rounds of amplification are carried out in a single tube. This results in fewer manipulations, reduced risk of contamination, and economy of time. The procedures are generally applicable to other assays based on the PCR. We describe the preparation (from 100 microL serum) of test samples that remain stable for at least 6 days under specified conditions and an assay that employs nested primer pairs homologous to conserved sequences in the 5' noncoding region. The method was tested on 107 sera from the United States and Japan. Correlation with first-generation anti-HCV was 77%. Two sets of nested primer pairs homologous to sequences in the 5' noncoding region and one set based on structural region sequences showed differences in their reactivities with serum HCV RNA. The recommended single tube procedure specified a primer for reverse transcription that was conserved in all reported HCV genomes but absent from pestivirus genomic sequences. The effects of preanalytical factors on the detection of HCV RNA were studied. Qualitatively, there was no change in the HCV RNA-positivity of sera that were exposed to room temperature for 24 hours. Quantitative studies showed a decrease in titer in some specimens. Three cycles of freeze-thawing had no detectable effects on the titers of HCV RNA.

Base Sequence↗

PubMed1992

Incidence of anti-HTLV-1 antibody in liver disease.

Positivity for serum anti-HTLV-1 antibody (anti-HTLV-1) in 171 patients with various chronic liver diseases and 22 asymptomatic hepatitis B virus (HBV) carriers was compared with that of 200 healthy controls in the Chikugo district of Japan. The rate of anti-HTLV-1 positivity in patients with liver disease was 8.1% (14/171) and was higher than that (3.5%: 7/200) in healthy controls, but the difference was not significant. However, in patients with liver disease with a history of blood transfusion, the positive rate was 18.4% (7/38) which was significantly higher than that for healthy subject (P less than 0.001). On the other hand, in 133 liver disease patients without blood transfusion, anti-HTLV-1 positivity was significantly higher (P less than 0.05) in patients with hepatitis B surface antigen (11.3%: 6/53) than in those without it (1.3%: 1/80). These data suggest that the high incidence of anti-HTLV-1 in our patients with liver disease was due to the transmission of HTLV-1 by the same routes (maternal transmission and blood transfusion) and probably at the same time as the hepatitis viruses (HBV and hepatitis C virus).

Adult↗

PubMed1992

[A case of HBsAg positive liver cirrhosis who died after withdrawal of steroid].

A 42-year-old male was admitted with subarachnoidal hemorrhage. Dexamethasone 224 mg was used to reduce brain edema. His operation was successful without blood transfusion. No remarkable signs and symptoms were found except HBsAg positive and mild GPT elevation during his admission. He was discharged on the 33rd day. But 2 weeks later, he felt general fatigue and became worse day by day. He was re-admitted on the 75th day. Several therapies were given but he died of hepatic failure on the 85th day. The autopsy showed liver cirrhosis with massive necrosis. We believed that the steroid-withdrawal-phenomenon caused excessive immunological response and this process caused his hepatic failure leading to death.

Adult↗

PubMed1992

Adipostatins A and B, new inhibitors of glycerol-3-phosphate dehydrogenase.

As a result of screening for inhibitors of glycerol-3-phosphate dehydrogenase, which may be effective to prevent corpulence, we isolated two inhibitors named adipostatin A and adipostatin B from the culture broth of Streptomyces cyaneus 2299-SV1. Their structures have been established to be 5-n-pentadecylresorcinol and 5-isopentadecylresorcinol, respectively. Adipostatin A and adipostatin B inhibited glycerol-3-phosphate dehydrogenase at the IC50 values of 4.1 microM and 4.5 microM, respectively. These compounds prevented triglyceride accumulation in 3T3-L1 cells at a concentration of the microM level.

3T3 Cells↗

PubMed1992

[The positive rate of hepatitis C virus antibody detected by the second generation method in pregnant women and influence of pregnancy and delivery on HCV infection].

The C100-3 antibodies to HCV can be examined with a Chiron kit but only the antibody to non-structure-4 can be. The antibodies in sera of pregnant women were examined by a passive hemagglutination method (PHA), which is one of the second generation kits used in detecting antibodies to the hepatitis C virus. We studied the percentage of pregnant women in our hospital with antibodies to HCV, and tried to compare the C100-3 antibodies with PHA results in pregnant women. The results are as follows. 1) In the sera of 235 pregnant women both the PHA antibody and the C100-3 antibody were examined. Two women (0.85%) had the C100-3 antibody and 4 (1.7%) had the PHA antibody. 2) Two women positive for both PHA and C100-3 antibodies were positive for PCR during pregnancy. But 2 women positive for PHA only were negative for PCR during pregnancy and positive after delivery. So 4 women positive for PHA had HCV RNA. 3) Next, the sera of 1,198 pregnant women were examined by the PHA method, and nine women were positive. Only four of the 9 were positive for C100-3. 4) It is speculated that the positive rate for anti-HCV antibodies in the sera of pregnant women in Nagoya city is 0.75%. 5) There were 3 cases that were negative for PCR during pregnancy and positive after delivery. So it is speculated that HCV can be activated after delivery.

Adult↗

PubMed1991

Treatment with human gamma interferon of chronic hepatitis B: comparative study with alpha interferon.

A pilot study was designed to determine the tolerance and effectiveness of natural or recombinant gamma interferon in patients with chronic hepatitis B. Sixteen patients received 0.5 to 3.0 million units (MU) per day of gamma interferon (IFN-gamma) for 7 days. Nineteen chronic hepatitis B patients who were treated with 5-6 MU leukocyte-derived alpha interferon (IFN-alpha) daily served as controls. All completed the treatment schedule. IFN-gamma exerted mild, but significant inhibitory effects (P less than .05) on serum DNA polymerase levels. However, the changes were significantly less (P less than .001) than those seen with IFN-alpha therapy when compared with percent change from basal values. In contrast, serum 2', 5'-oligoadenylate synthetase (2-5 AS) activities were markedly enhanced to a similar extent during therapy with both IFNs. Serum beta 2-microglobulin values were significantly increased by administration with both IFNs, although higher values were seen with IFN-gamma. Five patients received 1 MU IFN-gamma for 28 consecutive days and their HBeAg levels similarly decreased as those seen in patients treated with IFN-alpha. Side effects seemed to be greater during IFN-gamma therapy than IFN-alpha despite the lower doses used. The antiviral effect on serum HBV levels appeared less with IFN-gamma than with IFN-alpha. Alternatively immunomodulatory functions may have been enhanced with IFN-gamma in patients with chronic HBV infection.

Adolescent↗

PubMed1991

[Risk of hepatitis C virus infection by needlestick among medical employees].

We have experienced 99 medical employees who had stuck themselves by the needles used by patients in the past 5 years. Sixteen of the 99 cases (16.2%) were of the patients who had hepatitis C Virus (HCV) antibodies. We followed up these 16 medical employees during 24.8 +/- 12.0 months. We could not find any case among them who had seroconverted HCV antibody positive in their serums. We concluded that the risk of HCV infection by the needlestick accident is not so high.

Adult↗