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S Mishiro

Publications and source records attributed to S Mishiro.

At least 19 recordsLinked to original sources
PubMed1995

Detection of the GBV-C hepatitis virus genome in serum from patients with fulminant hepatitis of unknown aetiology.

Hepatitis viruses A, B, C, D, and E have not accounted for all cases of hepatitis, hence "non A-E" agent(s) might be implicated. A set of new viruses (GBV-A, -B, and -C) whose genomes have been sequenced, are being investigated as possible causes of non A-E hepatitis. We investigated six cases of fulminant hepatitis of unknown aetiology for the presence of GBV-C genome in their serum, and three showed positive signals by semi-nested PCR using primers derived from the NS3/helicase region. Nucleotide sequence analyses confirmed these signals to be derived from a GBV-C sequence. The results suggest the importance of GBV-C in the aetiology of fulminant hepatitis.

Adolescent↗
PubMed1995

Influence of the genotypes of hepatitis C virus on the severity of recurrent liver disease after liver transplantation.

BACKGROUND/AIMS: Several genotypes of hepatitis C virus (HCV) have been identified by phylogenetic analysis, but their clinical relevance remains elusive. Liver transplantation for HCV-related cirrhosis offers a unique opportunity for prospective studies of this issue. METHODS: Sixty anti-HCV-positive liver recipients with precise virological and histological assessments were included. HCV genotype was determined with both type-specific capsid primers and a line probe genotyping assay. RESULTS: HCV genotype 1b was the predominant type before transplantation (40 of 60 patients); after liver transplantation, acute and chronic active hepatitis developed more frequently in these patients than in patients infected by other genotypes (31 of 40 and 24 of 40 vs. 8 of 20 and 4 of 20 patients). Actuarial rates of acute hepatitis and chronic active hepatitis were 77% and 59%, respectively, 3 years after transplantation in patients infected by type 1b and 40% (P = 0.008) and 22% (P = 0.004) in those infected by other types. There was no statistical relation between the level of HCV viremia and HCV genotypes both before and after transplantation. In contrast, after transplantation, serum HCV RNA values were significantly increased in patients who developed hepatitis after transplantation. CONCLUSIONS: This study provides direct evidence that HCV 1b is associated with more aggressive recurrent liver disease than other genotypes.

Actuarial Analysis↗
PubMed1995

Transmission of hepatitis C virus from mothers to infants: its frequency and risk factors revisited.

A total of 16,714 pregnant Japanese women were tested for antibodies against hepatitis C virus (HCV), and 163 (0.98%) were positive. None of these were infected with human immunodeficiency virus-1 (HIV-1). We conducted a prospective study to discover the rate of HCV infection in babies born to mothers who were HCV RNA-positive but had no evidence for hepatitis (so called "asymptomatic carriers"), and only 2 (2.3%) of 87 such babies became infected during follow-up. This rate was considerably lower than those from other reports which included mothers with clinically overt chronic hepatitis C. We conducted another study to follow babies born to mothers with chronic hepatitis C, and found two babies infected. All of the four infected babies were born to mothers who had HCV RNA in their circulations around delivery at high titers (greater than 5.0 x 10(6) Eq/ml by branched DNA assay). This confirmed the previous finding that virus load was an important risk factor. In addition, we found three families where mother-to-infant HCV transmission was suspected in a retrospective study by indexing HCV-infected pediatric patients. Throughout the seven families, siblings of infected babies were free from HCV infection, suggesting that maternal infection of HCV owes much to chance. Breast milk feeding was not regarded as a risk factor. We also assessed the prevalence of anti-HCV antibody among 6-year old children, and only 10 of 10,446 (0.1%) were positive, suggesting low frequency of HCV infection during the period from birth to this age.

Carrier State↗
PubMed1994

A redox factor protein, ref1, is involved in negative gene regulation by extracellular calcium.

A rise in extracellular calcium (Ca2+e) suppresses not only secretion of parathyroid hormone (PTH) but also expression of the PTH gene to ensure constant plasma Ca2+ level. A nuclear protein(s) in a wide variety of cells bound to the specific DNA elements (negative Ca2+ responsive elements, nCaREs) in the human PTH gene in sequence-specific and Ca2+e concentration-dependent manners. Our Southwestern cloning revealed that a redox factor protein (ref1), which was known to activate several transcription factors via alterations of their redox state, belonged to an nCaRE binding protein. The level of ref1 mRNA as well as of its protein was elevated by an increase in Ca2+e concentration. In gel shift assay, anti-ref1 antibody eliminated formation of the nCaRE-protein complex. We also found that there was another protein(s) interacting with nCaREs and ref1. Further, experiments with an antisense-ref cDNA expression vector introduced into cultured cells suggested that DNA (nCaRE)-ref1 interaction led to Ca2+e-mediated transcriptional suppression. Thus, it is concluded that ref1 possesses transcription repressor activity in addition to its function as a transcriptional auxiliary protein.

Animals↗
PubMed1994

Hepatitis C virus variants from Vietnam are classifiable into the seventh, eighth, and ninth major genetic groups.

Thirty-four (41%) of 83 hepatitis C virus (HCV) isolates from commercial blood donors in Vietnam were not classifiable into genotype I/1a, II/1b, III/2a, IV/2b, or V/3a; for 15 of them, the sequence was determined for 1.6 kb in the 5'-terminal region and 1.1 kb in the 3'-terminal region. Comparison of the 15 Vietnamese isolates among themselves and with reported full or partial HCV genomic sequences indicated that they were classifiable into four major groups (groups 6-9) divided into six genotypes (6a, 7a, 7b, 8a, 8b, and 9a). Vietnamese HCV isolates of genotypes 7a, 7b, 8a, 8b, and 9a were significantly different from those classified into groups 4, 5, and 6 based on divergence within partial sequences; those of genotype 6a were homologous to a Hong Kong isolate (HK2) of genotype 6a. Phylogenetic trees based on the envelope 1 (E1) gene (576 bp) of 55 isolates and a part of the nonstructural 5 (NS5) region (1093 bp) of 43 isolates revealed at least nine major groups, three of which (groups 7, 8, and 9) were identified only in Vietnamese blood donors. With a prospect that many more HCV isolates with significant sequence divergence will be reported from all over the world, the domain of the HCV genome to be compared and criteria for grouping/typing and genotyping/subtyping will have to be determined, so that they may be correlated with virological, epidemiological, and clinical characteristics.

Base Sequence↗
PubMed1994

Hepatitis C virus infection in spouses of patients with type C chronic liver disease.

OBJECTIVE: Survey for markers of hepatitis C virus (HCV) infection in spouses of patients with HCV-related chronic liver disease. DESIGN: Cross-sectional clinical, serologic, and molecular biological study of spouses of patients with HCV viremia and chronic liver disease. SETTING: University and city hospitals. PARTICIPANTS: Spouses (52 men and 102 women; mean age, 56 +/- 11 years) of 154 patients with HCV viremia (102 men and 52 women; mean age, 58 +/- 10 years), of whom 66 had chronic hepatitis, 49 had liver cirrhosis, and 39 had primary hepatocellular carcinoma. METHODS: Tests for HCV-associated antibodies were done using a second-generation enzyme immunoassay and immunoassays with synthetic oligopeptides deduced from the HCV core gene. Hepatitis C virus RNA was detected by polymerase chain reaction with primers deduced from the 5'-noncoding region and HCV genotypes by reaction with type-specific primers deduced from the HCV core gene. RESULTS: Hepatitis C virus-associated antibodies were detected in 42 (27%) spouses, of whom 25 were also positive for HCV RNA. Of 112 (73%) spouses without detectable antibodies, 2 had chronic liver disease. The development of markers of HCV infection in spouses increased with the duration of marriage, ranging from 1 to 60 years (30 +/- 11 years). CONCLUSIONS: Spouses of patients with HCV viremia and chronic liver disease have an increased risk for acquiring HCV, which is proportional to the duration of marriage. They should be followed routinely for markers of HCV infection and liver disease.

Aged↗
PubMed1994

Safety and efficacy of a recombinant yeast-derived pre-S2 + S-containing hepatitis B vaccine (TGP-943): phase 1, 2 and 3 clinical testing.

A recombinant yeast-derived pre-S2 + S-containing hepatitis B vaccine (TGP-943) was clinically evaluated through three phases of testing in a total of 2137 volunteers. We observed the immunogenic purity of TGP-943 (phase 1), the inter-lot reproducibility of both safety and immunogenicity (phase 2), no significant side-effects, a high capability of inducing both anti-HBs and anti-pre-S2 antibodies (phases 1, 2 and 3), and an ability to induce seroconversion in the majority of vaccines who had been non-responsive to conventional hepatitis B vaccines (phases 2 and 3). In conclusion, TGP-943 is a safe and tolerable vaccine, with special merits: the ability to induce an early anti-pre-S2 response that circumvents the problem of delayed appearance of anti-HBs, and efficacy in non-responders to previous vaccination.

Adolescent↗
PubMed1994

Genetic heterogeneity of hepatitis C virus.

There are four hierarchical strata in the genetic heterogeneity of hepatitis C virus (HCV): group above subgroup above isolates above quasispecies. The entire genome sequence has so far been reported for 16 isolates which are classifiable into 3 groups and 6 subgroups. Provisional classification of HCV is also possible using a partial sequence of the HCV genome. With the E1 region sequence for example, the present collection of HCV isolates can be classified into 9 groups and 23 subgroups. The rationale for these classifications and the epidemiological and clinical implications of genotyping HCV are reviewed.

Amino Acid Sequence↗
PubMed1994

Superinfection of chimpanzees carrying hepatitis C virus of genotype II/1b with that of genotype III/2a or I/1a.

Three chimpanzees persistently infected with hepatitis C virus of genotype II/1b were challenged with hepatitis C virus of genotype III/2a and 6 wk later with hepatitis C virus of genotype I/1a. They were tested for titers of total and genotype-specific hepatitis C virus RNA, as well as for serum transaminase levels, until 52 wk after the first challenge. One chimpanzee (CH489) with intermittent low hepatitis C virus RNA titers of genotype II/1b in serum was superinfected with hepatitis C virus of genotype III/2a between wk 1 and 7 after the challenge; superinfection was accompanied by fluctuating high transaminase levels. Later, the animal was superinfected with hepatitis C virus of genotype I/1a. Superinfection was accompanied by persistently high transaminase levels immediately after the challenge. Hepatitis C virus of genotype I/1a persisted, whereas hepatitis C virus of genotype II/1b was undetectable 22 wk after the challenge and thereafter. In another chimpanzee (CH353) with intermittent low hepatitis C virus RNA titers of genotype II/1b, hepatitis C virus of genotype III/2a induced fluctuating high levels of serum transaminases without revealing itself in serum. Then, HCV of genotype I/1a superinfected her, induced persistently high transaminase levels and took over HCV of genotype II/1b at 22 wk after the challenge and thereafter. The third chimpanzee (CH451) with persistently high HCV RNA titers of genotype II/1b did not reveal HCV RNA of genotype III/2a in serum after the challenge, although transaminases sharply increased. Low-titered HCV RNA of genotype I/1a was detected at 18 wk after the challenge.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Prevalence, genotypes, and an isolate (HC-C2) of hepatitis C virus in Chinese patients with liver disease.

China has not been extensively investigated for the prevalence of hepatitis C virus (HCV) infection among people with or without liver disease. We analyzed serum from 2,177 liver disease patients from 7 cities in different areas of China. Of 435 acute hepatitis patients, only 11% were positive for HCV RNA, while hepatitis B surface antigen (HBsAg) was detected in 33%. Of 1,668 patients with chronic liver disease, 14% and 74% were positive for HCV RNA and HBsAg, respectively. Nearly 80% of non-B chronic liver disease were negative for HCV RNA. The frequency of HCV RNA in chronic liver disease was significantly higher in Hami (32%) and Shenyang (30%) than in other cities (6-12%). The HCV genotype distribution varied by region. Genotype III was detected in 46-70% of HCV infections in Hami, Shenyang, and Lanzhou, while more than 90% of patients from southern cities (Nanjing, Nanning, and Chengdu) had genotype II. No evidence for genotype I or IV infections was found. A full-length HCV genome sequence (HC-C2) derived from a Beijing patient with genotype II was closely related to previous isolates from Japanese and Taiwanese patients. These results suggest that HCV prevalence and genotype distribution vary from region to region in China, and that the HCV now predominant in China may have evolved epidemiologically with infections in Japan and Taiwan. The study identified a high frequency of non-B, non-C chronic liver disease in China, suggesting possibly a new agent or infections with extreme variants of HCV.

Base Sequence↗
PubMed1993

A structurally flexible and antigenically variable N-terminal domain of the hepatitis C virus E2/NS1 protein: implication for an escape from antibody.

Hepatitis C virus persists in most infected hosts, and causes chronic hepatitis, liver cirrhosis, and/or hepatocellular carcinoma in humans. During the infection the RNA genome of hepatitis C virus undergoes frequent missense mutations at one or two "hypervariable" regions within a presumptive envelope gene (Okamoto et al., 1992, Virology 190, 894-899; Ogata et al., 1991, Proc. Natl. Acad. Sci. USA 88, 3392-3396). In the present study, we analyzed three cases of hepatitis C virus infection, two in chimpanzees and one in humans, for the antigenicity of peptides predicted from the hypervariable region of viral RNA obtained during the follow-up. Our results showed a successive appearance of hepatitis C virus mutants with antigenically distinct amino acid sequence within the domain; and the amino acid replacement was associated with an alteration of predicted local secondary structure of the epitope region. Hence, the hypervariable domain of the hepatitis C virus envelope appeared to be structurally flexible and antigenically variable, providing the virus a way to escape from host immunity.

Amino Acid Sequence↗
PubMed1993

Demonstration of sugar moiety on the surface of hepatitis C virions recovered from the circulation of infected humans.

The amino acid sequence for the envelope protein(s) predicted from the nucleotide sequence of the E and E2/NS1 regions of the hepatitis C virus (HCV) genome is enriched with an N-linked glycosylation site motif, Asn-X-Thr/Ser, suggesting oligosaccharide moieties are present on the virion surface. We attempted to characterize the sugar moiety on the surface of HCV virions recovered from sera of infected humans to assess the natural properties of the virus. Six kinds of lectins were used to bind HCV virions in affinity column chromatographies: RCAI, WGA, Con A, AAL, LCA, and PNA. Lectin-bound virions were identified by detecting HCV RNA in eluted chromatography fractions with a polymerase chain reaction (PCR) method. Our results showed that HCV was similar to hepatitis B virus (HBV) in characteristics of binding to lectins: HCV showed a strong binding to RCAI and WGA, weak binding to Con A, and no detectable binding to AAL, LCA, or PNA. Treatment of the HCV virion preparation with an enzyme, glycopeptidase A, or a detergent, NP-40, resulted in a significant decrease in the ability to bind these lectins. Our results suggest that asparagine-linked sugar chains are present on the surface of native virions of HCV, very similar to those for HBV.

Amidohydrolases↗
PubMed1993

Characterization of the genomic sequence of type V (or 3a) hepatitis C virus isolates and PCR primers for specific detection.

We have identified four new hepatitis C virus (HCV) isolates whose genomic RNA could be amplified by PCR using primers from the 5' untranslated region (UTR), but the RNA could not be detected with genotype I to IV (or types 1a, 1b, 2a and 2b respectively)-specific core region-derived primers. We compared the nucleotide sequences of the new isolates from positions 65 to 1850 (3' end of 5' UTR, C, E1 and 5' end of E2/NS1) and 8276 to 9394 (3' end of NS5 and 3' UTR) with those for genotypes I to IV. The four isolates had the following characteristics: (i) the overall nucleotide sequence similarity between the four isolates was 95 to 96%, compared to 73 to 74%, 73%, 70% or 69 to 70% against genotypes I, II, III or IV, respectively; (ii) the sequence similarity to other reported 'type V (3a)' isolates was 88 to 100%; (iii) the hypervariable region 1 [(HVR)-1] was present but HVR-2 was absent within the E2/NS1 region; (iv) only one in-frame termination codon was present for the presumed polyprotein; (v) the 3'UTR preceding a terminal poly(U) stretch was significantly shorter than in genotype I to IV isolates. We classified the four isolates as genotype V (3a), and searched for uniquely conserved nucleotide sequences that could be used for type-specific PCR. A core region-derived primer pair (no. 104V: 5' CGTAAAACTTCT GAACGGTC, sense and no. 339: 5' GCTGAGCCCA GGACCGGTCT, antisense) was identified and successfully used to diagnose genotype V (3a) HCV infection.

Amino Acid Sequence↗