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Biomedical subjects

Y Akahane

Publications and source records attributed to Y Akahane.

At least 55 records · Page 3Linked to original sources
PubMed1993

Detection of hepatitis C virus markers and hepatitis C virus genomic-RNA after needlestick accidents.

BACKGROUND: Needlestick accidents are a problem among health care workers. Using sensitive new assays, we evaluated the prevalence and features of hepatitis C virus (HCV) infection following a needlestick accident. METHOD: The clinical outcome and evolution of serum HCV markers were assessed in 90 hospital employees (recipients) who sustained needlestick injuries (selected from 146 episodes) involving 92 patients with clinical non-A, non-B hepatitis (donors). RESULTS: Of the 92 patient donors, 62 (67%) and 88 (96%) were anti-C100-3 and second-generation anti-HCV positive, respectively, at the time of the needlestick accident. During the follow-up period (> or = 6 months), acute non-A, non-B hepatitis developed in three of 90 recipients about 1 month after the accident. The three respective donors were positive for serum HCV-RNA at the time of the accident. Two of the three recipients became HCV-RNA positive just after the onset of hepatitis, and subsequently, HCV antibodies developed. None of the remaining 87 recipients had any clinical or laboratory evidence of hepatitis during follow-up, or experienced seroconversion for anti-C100-3 or second-generation anti-HCV. We measured additional HCV markers in 20 of the 89 donors; 16 had evidence of HCV infection (HCV-RNA). However, none of the respective recipients of any of these 20 became positive for HCV markers during follow-up. CONCLUSION: Although transmission of HCV infection by needlestick injury may be infrequent, such transmission does occur. Appropriate precautions should be taken to protect health care workers.

Accidents, Occupational↗
PubMed1992

Serodiagnosis of hepatitis C virus infection by ELISA for antibodies against the putative core protein (p20c) expressed in Escherichia coli.

The putative core gene of hepatitis C virus (HCV) was incorporated into a plasmid vector (pCC5-J4), and expressed in Escherichia coli. The product of 180 amino acids (p20c) was purified by gel electrophoresis in the presence of sodium dodecyl sulfate, and used in enzyme-linked immunosorbent assay for antibodies against the putative core protein of HCV (anti-p20c). Anti-p20c was detected in 13 (1.5%) of 873 apparently healthy blood donors. It was detected in 205 (86.5%) of 237 patients with acute or chronic non-A, non-B (NANB) hepatic disease, significantly more frequently (p less than 0.01) than antibodies against the C100-3 protein encoded by nonstructural regions of HCV (anti-C100-3) that was found in 178 (75.1%). Anti-p20c developed in the circulation of a patient with acute NANB hepatitis much earlier than anti-C100-3. HCV RNA was detected by polymerase chain reaction in serum samples from blood donors positive for anti-p20c in high titers, one of which was negative for anti-C100-3. These results indicated that anti-p20c would be useful in complementing anti-C100-3 for the diagnosis of NANB hepatitis and further decreasing the incidence of posttransfusion NANB hepatitis.

Adolescent↗
PubMed1992

Antibodies against synthetic oligopeptides deduced from the putative core gene for the diagnosis of hepatitis virus infection.

Immunoassays were developed to detect antibodies against oligopeptides deduced from the putative core gene of hepatitis C virus, and their performances were compared with that of the commercial immunoassay for antibodies against the product of nonstructural regions of hepatitis C virus (anti-C100-3). A 19-mer oligopeptide (CP10) and a 36-mer oligopeptide (CP9) were chemically synthesized, which represented hydrophilic regions of the product of the hepatitis C virus core gene. They were used to capture corresponding antibodies, anti-CP10 and anti-CP9, by enzyme-linked immunosorbent assay in sera from patients with acute or chronic non-A, non-B liver disease and in blood donations. At the onset of acute non-A, non-B hepatitis, anti-CP10 was detected in 15 of 20 patients (75%), and anti-CP9 was detected in 14 patients (70%). This was more frequent than anti-C100-3, which was found in only 9 patients (45%). In 186 patients with chronic non-A, non-B liver disease, anti-CP9, anti-CP10 or both were detected in 170 patients (91%). This was more frequent than anti-C100-3, which was found in 138 patients (74%). Blood with anti-CP10 as the single serological marker for hepatitis C virus infection transmitted non-A, non-B hepatitis by needlestick exposure. In sera from 558 apparently healthy blood donors, anti-CP10 was detected in 55 donors (9.9%), anti-CP9 was detected in 26 donors (4.7%) and anti-C100-3 was detected in 7 donors (1.3%).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

The degree of variability in the amino terminal region of the E2/NS1 protein of hepatitis C virus correlates with responsiveness to interferon therapy in viremic patients.

We investigated amino acid heterogeneity in the variable regions of the E2/NS1 viral protein in interferon-responsive and interferon-nonresponsive patients with chronic hepatitis C virus infection. The study assessed whether any particular heterogeneity pattern(s) could be useful in predicting responsiveness to interferon treatment. The nucleic acid sequences of the hepatitis C virus genome were analyzed from six patients with chronic hepatitis treated with an interferon-beta, three of whom did not respond to the therapy and another three who showed remarkable improvement in the serum levels of liver enzymes and hepatitis C virus RNA after 6 mo. The complementary DNA clones propagated from each of the nonresponders showed significant diversity of both nucleotide and amino acid sequence, especially at the hypervariable region 1 within the putative E2/NS1 gene of the virus, suggesting that these patients were infected with a large heterogeneous pool of hepatitis C virus variants. In contrast, the responders showed little or no diversity in the sequence of the complementary DNA clones, suggesting that they were infected with one or a small population of viral genotypes containing significantly less variability in the E2/NS1 hypervariable region 1. These results suggested that a large variable population of hepatitis C virus genotypes is implicated in patients who are nonresponders to interferon treatment. In addition, a significant change in the hepatitis C virus genotype population was observed in nonresponders after interferon treatment. This may reflect a differential viral sensitivity to interferon, selective immune pressure by the host or both.

Adult↗
PubMed1992

Two distinct subtypes of hepatitis C virus defined by antibodies directed to the putative core protein.

Four distinct genotypes of hepatitis C virus types I, II, III and IV have been identified by comparison of nucleotide sequences of isolates from different areas of the world. We examined the possibility that hepatitis C virus may have serologically definable subtypes. Enzyme-linked immunosorbent assay systems were prepared by use of two synthetic peptides deduced from the putative core protein of hepatitis C virus. The following are the two peptides that were used: (a) IPKARRPEGRTWAQPGY (subtype-1) conserved in hepatitis C virus isolates with type I and type II genotypes; and (b) IPKDRRSTGKSWGKPGY (subtype-2) conserved in type III and type IV genotypes. With the enzyme-linked immunosorbent assays, the subtype-1 antibodies were detected in 26 (68%) of 38 subjects whose hepatitis C virus RNA had been genotyped as type I or type II, whereas subtype-2 antibodies were not detected. Inversely, the subtype-2 antibodies were detected in 10 (56%) of 18 subjects with hepatitis C virus RNA genotypes III or IV, whereas subtype-1 antibodies were detected in none of them. These results suggest that hepatitis C virus has two serologically distinguishable core antigen subtypes, corresponding to either genotype I/II or genotype III/IV. Subtyping of HCV by serological methods would contribute to tracking transmission routes of the virus, especially in cases where serum samples were not stored under conditions to preserve RNA or in infected hosts who have cleared the virus and therefore have only antibodies remaining to identify the infection.

Amino Acid Sequence↗
PubMed1992

Demonstration of a hepatitis C virus-specific antigen predicted from the putative core gene in the circulation of infected hosts.

An ELISA was used to detect a protein derived from the core gene of the hepatitis C virus (HCV) in human plasma. The solid phase antibody in the assay was a murine monoclonal antibody against a synthetic peptide deduced from the putative core gene of HCV (residues 39 to 74). An enzyme-labelled affinity-purified human antibody directed at another region within the HCV core (residues 5 to 23) was the second antibody tracer. The ELISA had a sensitivity capable of detecting a few ng/ml of the HCV core polypeptide expressed in Escherichia coli. Core antigen activity in plasma of infected hosts was detected after treatment of HCV RNA-rich fractions from buoyant density centrifugation with the detergent Tween 80. There was a direct correlation between core antigen ELISA values of a plasma fraction and intensities of polymerase chain reaction signals for HCV RNA. These observations are consistent with the proposal that the N-terminal sequence of the predicted polyprotein of HCV is a nucleocapsid protein, and that improved core antigen assays may correlate with viraemia.

Amino Acid Sequence↗
PubMed1992

Typing hepatitis C virus by polymerase chain reaction with type-specific primers: application to clinical surveys and tracing infectious sources.

Based on variation in nucleotide sequence within restricted regions in the putative C (core) gene of hepatitis C virus (HCV), four groups of HCV have been postulated in a panel of 44 HCV isolates. They were provisionally designated types I, II, III and IV. A method for typing HCV was developed, depending on the amplification of a C gene sequence by polymerase chain reaction using a universal primer (sense) and a mixture of four type-specific primers (antisense). HCV types were determined by the size of the products specific to each of them. Type II was found in HCV samples from 131 (82%) of 159 blood donors, more often than in those from 48 (60%) of 80 patients with non-A, non-B (NANB) liver disease in Japan (P less than 0.01). In 11 haemophiliacs who had received imported coagulation factor concentrates, type I was found in five, as against type II in four. Double infection with two different HCV types was found in two patients with chronic NANB liver disease (types I and II; II and III) and two haemophiliacs (types I and II; I and III). HCV types were identical in mother and baby in each of two examples of perinatal transmission, and were also identical in donor and recipient in a case of accidental needle exposure.

Base Sequence↗
PubMed1991

Intrafamilial transmission of hepatitis C virus in Japan.

To clarify the intrafamilial transmission of hepatitis C virus (HCV), the prevalence of antibody to HCV (anti-HCV) in 107 index patients with type C chronic liver disease was studied and compared with the prevalence of anti-HCV antibody in their 296 family members. Of the 85 index patients who were positive for anti-HCV, 15 (8%) of 196 of their family members were also HCV antibody positive, whereas of the 22 index patients who were anti-HCV antibody negative, none of the family members of the 100 evaluated was positive for anti-HCV antibody, a statistically significant difference between groups (P less than 0.02). No specific relative (spouse, child, parent, and sibling) was linked to HCV positivity in the index cases making it difficult to identify the route of infection that is believed to occur via the parenteral route in the home or community.

Adolescent↗
PubMed1991

Variceal bleeding after endoscopic injection sclerotherapy: an analysis of 108 subjects undergoing endoscopic injection sclerotherapy.

Among 108 cases of endoscopic injection sclerotherapy (EIS) performed from January 1984 through September 1989, post-EIS variceal bleeding occurred in 38 case (35%). Death was significantly more frequent among the post-EIS bleeders than non-bleeders (55% v. 27%). Background factors were analyzed for failure to prevent bleeding. The curve of the cumulative non-bleeding rate following emergency EIS (21 cases) was significantly lower (P less than 0.01) than that following elective EIS (22 cases), and there was more frequent rebleeding (13/21 v. 7/22) within a shorter mean period of time (4.9 months v. 14.1 months) in the former; association of hepatocellular carcinoma was also more frequent (13/21 v. 3/22). Continuation of drinking showed no difference between post-EIS bleeders (5/38) and non-bleeders (9/70). After complete variceal eradication the curve of the cumulative non-bleeding rate was significantly higher than after incomplete eradication (P less than 0.001). Following prophylactic EIS (65 cases) there was significantly less frequent bleeding (P less than 0.01) than following EIS performed after variceal rupture (43 cases). The risk of variceal bleeding after EIS can be minimized by complete eradication of varices at the initial EIS. Prophylactic EIS was suggested to contribute to reducing the frequency of post-EIS bleeding.

Emergencies↗
PubMed1991

Hepatitis B and C virus infection in Ujung Pandang, Indonesia.

A survey was performed to investigate HBV and HCV infection in Ujung Pandang. The total number of subjects was 406; 196 blood donors, 78 cases of acute hepatitis, 43 of chronic hepatitis, 58 of liver cirrhosis and 31 of hepatocellular carcinoma cases. HBsAg, anti-HBs and anti-HBc as HBV markers and anti-HCV (ELISA, Ortho) as an HCV marker were tested. Positive rates of HBsAg and anti HCV among blood donors were 7.1% and 3.1% respectively, and there was no significant difference among age groups. Donors negative for all viral markers accounted for 21.4%. Of acute hepatitis cases, 18 (23.1%) cases were hepatitis A and 8 (10.3%) cases were hepatitis B, one case of which was considered to be double infection. Acute exacerbation cases of HBV carriers were 16 (20.5%), of which 6 cases were positive for HCV antibody. Those diagnosed non-A, non-B hepatitis were 37 (47.4%), of which 3 cases where positive for HCV antibody. Blood samples from all of acute hepatitis cases were obtained within 1 week after onset of the disease, thus, it was not possible to accurately assess prevalence of hepatitis C. Positive rates on HBsAg among chronic hepatitis, liver cirrhosis and hepatocellular carcinoma were 25.4%, 32.8% and 35.5% respectively, while those for HCV antibody were 16.3%, 43.1% and 35.5% respectively. Positive rates of HBsAg and HCV antibody for overall chronic liver diseases were 31.1% and 32.6%, and 14 (10.6%) were positive for both markers.

Adolescent↗
PubMed1991

Seroepidemiology of HBV and HCV infection in Jakarta, Indonesia.

A total of 545 serum samples were consecutively collected from patients with acute hepatitis, chronic hepatitis, liver cirrhosis, hepatocellular carcinoma, chronic hemodialysis and voluntary blood donors to study the seroepidemiology of HBV and HCV infection in Jakarta. Fourteen out of 243 or 5.8% samples from blood donors were HBsAg-positive, while HCV-antibodies (anti-C100 and/or anti-CP9 and/or anti-CP10) positivity rate was found in 59 out of 243 or 24.3%. Out of 91 donors aged 29 years or younger, 15 (16.5%) donors turned positive for HCV-antibody (-ies), while out of 152 donors aged 30 years or above, 44 (28.9%) donors were anti-HCV-positive, showing a higher HCV-antibody prevalence among higher age group. Among 88 acute hepatitis patients, 33 (37.5%) cases, 10 (11.4%) cases, 15 (17.0%) cases and 30 (34.1%) cases were diagnosed as hepatitis A, hepatitis B, acute exacerbation of HCV carriers, and NANB hepatitis respectively. HCV-antibodies were found in 15 (45.5%) of hepatitis A cases and 6 (40.0%) of acute exacerbation of HBV carrier cases, but found only in 9 (30.0%) of acute NANB hepatitis cases. Positivity rates of HCV-antibodies among 23 chronic hepatitis, 80 liver cirrhosis and 64 hepatocellular carcinoma cases were 78.3%, 75.0% and 65.6% respectively, while 30.4%, 30.0% and 45.3% of the respective groups were positive for HBs antigen. Among 47 hemodialysis cases, 97.9% and 6.4% were positive for HCV antibodies and HBs antigen respectively. It was concluded that: (1) HBV infection rate is high among blood donors and patients with acute and chronic liver diseases. (2) HCV infection rate is high among blood donors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Fulminant hepatitis B: induction by hepatitis B virus mutants defective in the precore region and incapable of encoding e antigen.

Clones of hepatitis B virus were propagated from 10 cases of fulminant hepatitis B after amplification by polymerase chain reaction and their nucleotide sequences of the precore region were determined. All 113 clones from 9 cases had a point mutation from guanine to adenine at nucleotide 83 in the precore region, which converted codon 28 for tryptophan (TGG) to a stop codon (TAG) and prohibited the synthesis and secretion of hepatitis B e antigen. Precore-region defects were not detected in any of 23 clones from the remaining 1 case. By contrast, precore-region defects were not found in any of 180 clones from 8 cases of acute hepatitis B without hepatic failure serving as controls. The source of infection was traceable in 3 cases. The same precore-region defect, along with the sequence identity of 435 nucleotides, was observed in clones from the case of a baby and his grandmother, who carried the virus and was implicated in the transmission, and also in clones from two pediatricians and the carrier patients they attended. These findings support the hypothesis that precore-defective mutants have stronger activity to induce fulminant hepatitis than nondefective viruses.

Adolescent↗
PubMed1991

Induction of protection level of anti-pre-S2 antibodies in humans immunized with a novel hepatitis B vaccine consisting of M (pre-S2 + S) protein particles (a third generation vaccine).

An enzyme-linked immunosorbent assay (ELISA) for anti-pre-S2 antibodies was developed by the use of both recombinant yeast-derived S and M (pre-S2 + S) protein particles as antigens. By this ELISA was determined the amount of both human and chimpanzee anti-pre-S2 antibodies produced by a new type of yeast-derived hepatitis B (HB) vaccine (TGP-943, subtype adr), which consists of modified M protein particles. In seven randomly selected human individuals who were vaccinated intramuscularly with 10 micrograms (as a protein) TGP-943 three times (0, 4th and 24th week), a detectable level of anti-pre-S2 antibodies was found to be rapidly elicited at 4th or 8th week after the first vaccination. The protective level of anti-pre-S2 antibodies in humans was tentatively assessed by comparing the anti-pre-S2 antibody titres in the vaccinated human individuals with that in chimpanzees which produced only anti-pre-S2 antibodies to tolerate well against the challenge by 1000 chimpanzee infectious units of HBV (subtype ayw). From this assessment, it was speculated that all human individuals tested had already acquired the protective level of anti-pre-S2 antibodies at 4th or 8th week after the first vaccination with TGP-943.

Animals↗
PubMed1991

Expression of hepatitis B surface antigen subtypes in liver of patients with hepatocellular carcinoma; comparison of subtypes in serum and liver.

To clarify the discrepancy in hepatitis B surface antigen (HBsAg) subtypes present in the serum and liver, as well as among hepatocytes, liver specimens which were resected from 37 HBsAg-positive patients with hepatocellular carcinoma (HCC) were examined. We evaluated HBsAg and the subtypic determinants of HBsAg and hepatitis B core antigen (HBcAg) using the peroxidase-antiperoxidase (PAP) staining method. Hepatitis B antigens were more frequently detected in small tumors (HBsAg in 67%. HBcAg in 40%) than in large ones (HBsAg in 36%, HBcAg in 14%). The prevalence of each subtypic determinant in the HBsAg positive non-tumorous vs. tumorous areas was 100% vs. 67% in a, 100% vs. 57% in d, 100% vs. not tested in y, 100% vs. 53% in r and 25% vs. 0% in w (a, d, y, r and w represent subtypic determinants). There was virtually no difference in a set of subtypic determinants between the serum and liver. However, there were some variations in a set of subtypic determinants among the hepatocytes. On the other hand, liver tissue of compound subtype adyr in serum contained both cells with a,d,r and with a,y,r as well as a few cells with a,d,y,r. These findings suggest that HBV genomes in hepatocytes of type B chronic liver disease may differ genetically among cells even in the same liver tissue.

Adult↗
PubMed1991

Phosphorylation in the carboxyl-terminal domain of the capsid protein of hepatitis B virus: evaluation with a monoclonal antibody.

The capsid protein of hepatitis B virus (p21c) is made of 183 amino acids coded for by the C gene. By using p21c isolated from Dane particles (hepatitis B virus) as an immunogen, a monoclonal antibody (no. 2212) which recognized an epitope dependent on the phosphorylation of p21c was raised. The binding of no. 2212 antibody to authentic p21c was completely inhibited by a synthetic undecapeptide with a sequence of RRRSQSPRRRR, representing amino acids 165 to 175 of p21c, only when the peptide was phosphorylated. Either or both of Ser-168 and Ser-170 were phosphorylated in p21c in vivo, therefore, and contributed to the manifestation of the epitope. No. 2212 antibody bound to p21c from core particles derived from Dane particles or hepatocellular carcinoma tissues (PLC/342) propagated in nude mice but did not bind to p21c from core particles expressed in Escherichia coli or yeast cells, indicating different states of phosphorylation in them. Nonphosphorylated p21c showed a higher affinity for the viral DNA than did phosphorylated p21c. Since the serum from an asymptomatic carrier, with a high titer for antibody to hepatitis B core antigen, specifically bound to phosphorylated undecapeptide (amino acids 165 to 175), the epitope would stimulate humoral antibody responses in the human host.

Amino Acid Sequence↗
PubMed1990

Non-A, non-B hepatitis specific antibodies directed at host-derived epitope: implication for an autoimmune process.

A cDNA clone (GOR47-1) bearing an epitope with an aminoacid sequence GRRGQKAKSNPNRPL (GOR epitope) was isolated from the plasma of a laboratory chimpanzee infected with human non-A, non-B hepatitis (NANBH) agent. The epitope was not encoded by reported sequences of hepatitis C virus (HCV) but instead was coded for by a host cellular sequence. An enzyme-linked immunosorbent assay (ELISA) was developed for antibodies to the GOR epitope (anti-GOR). A patient with acute NANBH produced both IgM and IgG classes of anti-GOR in the acute phase of the illness, with concentrations of IgG class anti-GOR rising when anti-HCV became detectable. Anti-GOR was detected in serum from 59 (81%) of 73 patients with chronic NANBH, 40 (65%) of 62 with NANB liver cirrhosis, and 25 (63%) of 40 NANB patients with primary hepatocellular carcinoma, but in only less than 10% of patients with chronic liver diseases due to hepatitis B virus, alcohol, or an autoimmune disorder, and in only 2% of voluntary blood donors. Circulating HCV-RNA was detected by polymerase chain reaction (PCR) in most patients seropositive for anti-GOR but negative for anti-HCV. Detection of anti-GOR would therefore help in the diagnosis of NANBH and in reducing the occurrence of post-transfusion hepatitis.

Amino Acid Sequence↗
PubMed1990

Interrelationship of blood transfusion, non-A, non-B hepatitis and hepatocellular carcinoma: analysis by detection of antibody to hepatitis C virus.

To clarify the relationship between hepatitis C virus infection and the development of hepatocellular carcinoma as sequelae of non-A, non-B posttransfusion hepatitis, 231 patients with chronic non-A, non-B hepatitis (96 with chronic hepatitis, 81 with cirrhosis and 54 with hepatocellular carcinoma) were analyzed for antibody to hepatitis C virus and were compared with 125 patients with chronic hepatitis B (50 with chronic hepatitis, 46 with cirrhosis and 29 with hepatocellular carcinoma). Antibody to hepatitis C virus was detected in 89.6%, 86.4% and 94.4% of patients with non-A, non-B hepatitis-related chronic hepatitis, cirrhosis and hepatocellular carcinoma, respectively, compared with 6%, 17.4% and 34.5% with similar diseases related to hepatitis B. A history of transfusion was documented in 52%, 33% and 42% of anti-hepatitis C virus-positive cases of chronic hepatitis, cirrhosis and hepatocellular carcinoma. The mean intervals between the date of transfusion and the date of diagnosis of anti-hepatitis C virus-positive chronic hepatitis, cirrhosis and hepatocellular carcinoma were 10, 21.2 and 29 yr, respectively. In 21 patients with transfusion-associated hepatocellular carcinoma, anti-hepatitis C virus was present in each serial sample available for testing, including samples obtained up to 14 yr before the diagnosis of hepatocellular carcinoma. These data suggest the slow, sequential progression from acute hepatitis C virus-related non-A, non-B hepatitis through chronic hepatitis and cirrhosis to hepatocellular carcinoma and support a causal association between hepatitis C virus and hepatocellular carcinoma.

Aged↗