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Biomedical subjects

Y Akahane

Publications and source records attributed to Y Akahane.

At least 37 records · Page 2Linked to original sources
PubMed1998

Hepatitis B virus genomic sequence in the circulation of hepatocellular carcinoma patients: comparative analysis of 40 full-length isolates.

We determined full-length nucleotide sequence of hepatitis B virus (HBV) genome in sera from 40 Japanese patients with HBsAg-positive hepatocellular carcinoma (HCC), in order to obtain information on HCC-specific characteristics, if any, of the HBV genome. Direct sequencing of the long distance PCR products starting from 50 microliters of serum samples revealed that 95% of our isolates were of genotype C, and that mutations and deletions/insertions were very common. With respect to envelope protein genes, deletions and missense mutations were frequent in preS2, and the determinant a domain of HBsAg was rich in "antibody-escape" mutations. Within the precore/core region, the most remarkable mutation was the replacement of proline of wild type by other amino acids at codon 130 of the core gene, which was found in 58% of our isolates, while precore-stop mutation was found in 45%. Most interestingly, however, about 90% of our isolates had mutations at nt positions 1762 (A-to-T) and 1764 (G-to-A) within the core promoter, which had been implicated in "e-suppressive" phenotype of HBV genome. G-to-A at nt 1613 and C-to-T at nt 1653 within enhancer II and T-to-C/A at nt 1753 within core promoter were also evident: 38%, 53%, and 40%, respectively. It was interesting that some of the characteristics observed in our isolates form HCC patients had been previously implicated in fulminant hepatitis and/or acute exacerbation of chronic hepatitis.

Adult↗
PubMed1998

Fecal excretion of a nonenveloped DNA virus (TTV) associated with posttransfusion non-A-G hepatitis.

Five patients with type B or C hepatocellular carcinoma were found to be infected with a nonenveloped DNA virus (TTV) associated with posttransfusion hepatitis of non-A-G etiology. Paired feces and serum samples from these patients were tested for TTV DNA by polymerase chain reaction with seminested primers and their sequences were compared. TTV DNA was detected in sera from all of the patients, while it was detected in feces from three patients, including two with high viral titers in serum. When feces and serum from one patient were subjected to floatation ultracentrifugation in CsCl, TTV in feces banded at a peak density of 1.35 g/cm3 and that in serum at 1.31-1.32 g/cm3. TTV isolates in three pairs of feces and serum had the identical sequence of 222 base pairs. The excretion of TTV into feces indicates that TTV would be transmitted not only parenterally but also nonparenterally by a fecal-oral route.

Base Sequence↗
PubMed1997

GB virus C and hepatitis C virus infections in hemodialysis patients in eight Japanese centers.

RNA of a putative non-A to E hepatitis virus, designated GB virus C (GBV-C), was detected in 40 (6.2%) of 645 hemodialysis patients, at a frequency significantly higher than in 3 (0.9%) of 336 blood donors in Japan (p < 0.001). A history of transfusion was more frequent (88 vs. 58%, p < 0.001), the duration of dialysis was longer (13.2 +/- 7.9 vs. 7.9 +/- 6.5 years, p < 0.001), and the detection of hepatitis C virus RNA was more often (38 vs. 18%, p < 0.01) in the 40 patients with GBV-C RNA than in the 605 patients without it. The prevalence of GBV-C RNA varied widely from 0 to 10% among the 8 dialysis centers. These results indicate that hemodialysis patients would be at increased risk of GBV-C transmitted by transfusions. The detection of GBV-C RNA in the 5 patients without a history of transfusion and a high prevalence restricted to certain dialysis centers would reflect nosocomial infection.

Alanine Transaminase↗
PubMed1997

Response to interferon of GB virus C and hepatitis C virus in patients with chronic hepatitis.

OBJECTIVES: To evaluate the response to interferon and capacity to induce liver disease of a putative non-A to E hepatitis virus designated GB virus C (GBV-C). METHODS: RNA of GBV-C was detected by reverse transcription polymerase chain reaction with nested primers deduced from the 5'-noncoding region. It was titrated, along with RNA of hepatitis C virus (HCV), in 16 co-infected patients (11%) out of 140 patients who received interferon. RESULTS: At the completion of a 6-month course of interferon (total dose: 516-774 million units), GBV-C RNA disappeared from serum in seven (44%) and HCV RNA from serum in 11 (69%) patients. At 6 months after interferon treatment ended, GBV-C RNA remained cleared in three patients (19%), and HCV RNA was persistently undetectable in four (25%). One patient lost both GBV-C and HCV RNAs. The three patients whose serum was cleared of GBV-C RNA had pretreatment titers of the virus (two with 10[1]/ml and one with 10[2]/ml) that were considerably lower than the titers of 13 patients (one with 10[2]/ml, eight with 10[3]/ml, and four with > or = 10[4]/ml) without such clearance. The decrease in alanine aminotransferase levels paralleled the response of HCV RNA but not that of GBV-C RNA to interferon. The response of HCV at 6 months after interferon in the co-infected patients (4/16 or 25%) did not differ significantly from that in patients without GBV-C infection (44/124 or 35%). CONCLUSIONS: The sensitivity of GBV-C to interferon is comparable to but independent of HCV. Co-infection with GBV-C does not influence the response to interferon of patients with chronic hepatitis C.

Antiviral Agents↗
PubMed1996

Mutations in the envelope gene of hepatitis B virus variants co-occurring with antibody to surface antigen in sera from patients with chronic hepatitis B.

Three clones of hepatitis B virus (HBV) DNA were propagated from sera of each of five patients with chronic hepatitis B who possessed hepatitis B surface antigen (HBsAg) and antibody to HBsAg in their serum. The clones were sequenced within the envelope gene (the preS1, preS2 regions and the S gene). Clones from four patients had various missense mutations involving codons 124-147 of the S-gene which encode amino acids in the loop structures that form the conformational, common antigenic determinant of HBsAg. Clones from three patients had Asn-130 (Gly in the wild-type), which generated a potential N-glycosylation site, Asn-Thr-Ser, spanning amino acids 130-132 of the S-gene product. In addition, clones from one patient had Arg-145 (Gly in the wild-type), which has been reported in escape mutants of HBV. One of the three clones from another patient had Ser-126 in place of lle or Thr in wild-type HBV, but the remaining two had no mutations known to affect expression of the common determinant of HBsAg. The remaining patient possessed HBsAg of subtype adr and anti-HBs specific for the w determinant. Clones from this patient did not reveal any mutations which are known to affect the common antigenic determinant of HBsAg.

Amino Acid Sequence↗
PubMed1996

Cold activation of complement for monitoring the response to interferon in patients with chronic hepatitis C.

OBJECTIVES: Because of its specific association with hepatitis C virus (HCV) infection, the cold activation of complement is an easy and inexpensive indicator of HCV viremia. It was evaluated for eligibility as a marker of response to interferon in patients with hepatitis C. METHODS: The cold activation of complement was determined by the loss or decrease of hemolytic activity with the microtitration method in sera that had been stored at 4 degrees C overnight. RESULTS: We observed the loss of hemolytic activity by the cold activation of complement in 236 (72%) and a decrease in 56 (17%) of 327 sera from patients with HCV-associated chronic liver disease, which was much more (p < 0.001) that in 1 (1%) and 13 (14%), respectively, of 49 sera from patients with chronic liver disease associated with hepatitis B virus infection. Interferon-alpha (total dose 516 x 10(6) units) or interferon-alpha 2b (774 x 10(6) units) was given to 67 patients with chronic hepatitis C, of whom 56 had the cold activation of complement. The response to interferon was evaluated by the clearance of serum HCV RNA at 6 months after the completion of therapy. The cold activation of complement disappeared in 18 patients, of whom 15 (86%) responded. It persisted or fluctuated in the remaining 38 patients, only six (16%) of whom responded to interferon (p < 0.001). The cold activation of complement once disappeared at the completion of interferon and then reappeared in patients who relapsed after completing interferon therapy. CONCLUSIONS: These results indicate that the cold activation of complement may be associated with the presence of HCV in blood and a lower rate of durable response after completion of interferon therapy.

Adult↗
PubMed1995

Hepatitis B virus strains with mutations in the core promoter in patients with fulminant hepatitis.

OBJECTIVE: Fulminant hepatitis B can be induced by hepatitis B virus (HBV) strains with mutations in the precore region that cannot encode hepatitis B e antigen (HBeAg). Such mutations are rarely seen in HBV DNA clones from patients with fulminant hepatitis B in the United States and France. Thus, the other mutations in HBV strains causing fulminant hepatitis B need to be identified. DESIGN: Retrospective clinical, serologic, and molecular biological studies of patients with fulminant hepatitis B. SETTING: University and city hospitals in Japan. PATIENTS: 43 patients with fulminant hepatitis B. MEASUREMENTS: The precore region coding for a part of the HBeAg precursor and the core promoter regulating the transcription of precore messenger RNA were sequenced in HBV DNA clones. RESULTS: A point mutation from G to A at nucleotide 1896 in the precore region was detected in 519 (98%) of 529 HBV DNA clones from 38 patients. Two point mutations in the core promoter, from A to T at nucleotide 1762 and from G to A at nucleotide 1764, were detected in all 130 clones from the remaining 5 patients, who did not have mutations in the precore region, and in 20 (63%) of 32 clones from a patient with chronic hepatitis B who had transmitted HBV to 1 of these other 5 patients. Mutations in the core promoter were also detected in clones from 26 (68%) of the 38 patients with the precore mutation at nucleotide 1896. Neither HBeAg nor antibody to HBeAg was detected in 37 (90%) of the 41 patients tested. CONCLUSIONS: In Japan, fulminant hepatitis B is closely associated with HBV strains that do not produce HBeAg because of mutations in the precore region, which affect translation of HBeAg, or because of mutations in the core promoter, which affect transcription of the HBeAg coding region.

Acute Disease↗
PubMed1995

Cold activation of complement as a marker of hepatitis C viremia in sera from blood donors.

Sera from 49,088 blood donors were tested for markers of hepatitis C virus (HCV) infection and decreased hemolytic activity after they had been stored at 4 degrees C for 24 h, a phenomenon known as the cold activation of complement. Antibody to HCV (anti-HCV) was detected in 315 (0.64%) units, of which 181 (57%) were positive for HCV RNA. The cold activation of complement was detected in 170 (0.35%) units, and HCV RNA was detected in 140 (82%) of them. Thus, the cold activation of complement was observed in 140 (77%) of 181 blood units with HCV RNA. The close association of HCV viremia with the cold activation of complement would be useful as a surrogate test in preventing post-transfusion HCV infection in developing areas where anti-HCV assays are not easily performed.

Biomarkers↗
PubMed1995

The precore/core promoter mutant (T1762A1764) of hepatitis B virus: clinical significance and an easy method for detection.

Recently, a new hepatitis B virus (HBV) mutant with HBe antigen-negative phenotype has been characterized, in which one TATA box-like motif of the precore/core promoter had degenerated: most frequently by both A-->T and G-->A mutations at positions 1762 and 1764, respectively. The clinical significance of this mutant is as yet unknown. In our present study, the T1762 A1764 mutant was sought in sera from HBV-infected blood donors and chronic liver disease patients by directly sequencing a PCR-amplified region of HBVDNA. Also, because the A1764 mutation generates a Sau3AI cleavage site (GGTC-->GATC), we digested the PCR products with Sau3AI to see if cleavage would occur at this specific site. Our results mostly corroborated the earlier report but we found a higher-than-predicted frequency of HBe antigen-positive blood donors positive for the mutant (22%). The titres of HBe antigen in these mutant-positive sera were slightly decreased compared to the titres in wild-type HBV infection. In addition, these blood donors had relatively high (though within the normal range) serum alanine aminotransferase (ALT) levels, suggesting that the T1762 A1764 mutation could be used as a sensitive laboratory marker for insidious hepatitis in these otherwise 'asymptomatic' carriers. The Sau3AI assay, which is much more convenient than sequencing, was shown to be useful for the detection of the T1762 A1764 mutant in an extensive number of clinical samples.

Alanine Transaminase↗
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

Adult mesenchymal hamartoma of the liver mimicking bile duct cystadenoma.

We report a rare case of mesenchymal hamartoma in the cirrhotic liver of a 52-year-old Japanese male. The tumor, 3.5 cm in diameter, contained a cystic lesion and was located in the lateral segment. Bile duct cystadenoma was considered most likely preoperatively because of the patient's age and the normal levels of tumor markers. However, since malignancy of the lesion could not be ruled out by preoperative imaging diagnosis, lateral segmentectomy was performed. Histological examination led to a diagnosis of mesenchymal hamartoma, since the lesion consisted of a multilocular abnormal bile duct accompanied by abundant myxomatous or loose collagen.

Bile Duct Neoplasms↗
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

Prompt decrease of circulating hepatitis C virus in patients with chronic hepatitis C after treatment with interferon.

Patients with chronic hepatitis C were treated with interferon (IFN) and followed for hepatitis C virus (HCV) RNA and antibody to HCV (anti-HCV) in serum. The response was correlated with decrease in serum levels of HCV RNA, as well as HCV genotypes and liver histopathology. Response to IFN, estimated by clearance of HCV RNA and normalization of aminotransferase levels at 6 months after the withdrawal of IFN, was observed in 11 (31%) of 35 patients infected with HCV of genotype II/1b, 13 (72%) of 18 with genotype III/2a, and 2 (33%) of 6 with genotype IV/2b; a single patient with genotype I/1a responded while the one doubly infected with HCV of genotypes II/1b and IV/2b did not. Response was seen in 10 (71%) of 14 patients with chronic persistent hepatitis, 14 (39%) of 36 with chronic active hepatitis 2A, and 3 (27%) of 11 with 2B. Response was achieved less often in patients with high than low pretreatment levels of HCV RNA. HCV RNA dropped sharply on a day after the start of IFN, and continued to decrease during the 2 weeks, irrespective of the response to IFN or HCV genotypes. In contrast, anti-HCV decreased more gradually and only in responders to IFN. These results support the rapid development of an IFN-mediated antiviral effect on HCV, and support therapeutic effects of IFN dependent on histopathology of liver as well as HCV RNA titers and genotypes.

Alanine Transaminase↗
PubMed1994

Entire nucleotide sequence and characterization of a hepatitis C virus of genotype V/3a.

The entire nucleotide sequence of a hepatitis C virus (HCV) genome (NZL1) of genotype V/3a was determined from overlapping cDNA clones obtained from a human carrier in New Zealand. It comprised 9425 nucleotides (nt) including a 5'-untranslated region of 339 nt, a single large open reading frame encoding a polyprotein of 3021 amino acids, a 3'-untranslated region of 23 nt, and 3'-terminal poly(U) stretches of variable lengths. The NZL1 genome was compared with 15 HCV isolates of other genotypes for which the full-length sequence has been determined. It differed from them by 31.1 to 34.3% in nucleotide sequence identity and by 24.5 to 29.1% in amino acid sequence identity, confirming the distinction of genotype V/3a from the other isolates.

Amino Acid Sequence↗
PubMed1994

Hepatitis B virus with mutations in the core promoter for an e antigen-negative phenotype in carriers with antibody to e antigen.

Hepatitis B virus (HBV) DNA clones were propagated from 57 carriers with antibody to hepatitis B e antigen (HBeAg) and sequenced within nucleotides (nt) 1685 to 1926 including the core promoter (nt 1742 to 1849) and the pre-C region (nt 1814 to 1900). Mutations in the core promoter or those in the pre-C region, or both, were detected in 328 (97.9%) of 335 clones from them. Five carriers were infected with HBV mutants with mutations in the core promoter alone, while 20 carriers were infected only with those in the pre-C region to abort the translation of HBeAg precursor; the remaining 32 carriers were infected with HBV mutants with mutations in both the core promoter and pre-C region. Some carriers infected with HBV with mutations in the core promoter exclusively had high HBV DNA titers, comparable with those in carriers infected with wild-type HBV, thereby indicating that such mutations would not affect the transcription of the HBV pregenome extensively. Two point mutations in the core promoter, from A to T at nt 1762 and from G to A at nt 1764, were most prevalent. The other mutations included a point mutation at either of the two nucleotides and their deletion. All of these mutations involved the TTAAA sequence (nt 1758 to 1762) at 28 bp upstream of the initiation site for shorter pre-C mRNAs (nt 1790 +/- 1). The ATAAATT sequence (nt 1789 to 1795) at 23 bp upstream of the initiation site for the pregenome RNA (nt 1818), however, remained intact in all 335 HBV DNA clones. HBV mutants with mutations in the core promoter, unaccompanied by pre-C mutations, prevailed and replaced wild-type HBV in two carriers as they seroconverted from HBeAg to the corresponding antibody. These results indicate that HBV mutants with an HBeAg- phenotype would be generated by mutations in the core promoter which might abort the transcription of pre-C mRNA but do not seriously affect that of pregenome RNA.

Adult↗
PubMed1994

Naturally occurring escape mutants of hepatitis B virus with various mutations in the S gene in carriers seropositive for antibody to hepatitis B surface antigen.

Hepatitis B virus (HBV) DNA was extracted from sera of six carriers with hepatitis B e antigen as well as antibody to hepatitis B surface antigen and sequenced within the pre-S regions and the S gene. HBV DNA clones from five of these carriers had point mutations in the S gene, resulting in conversion from Ile-126 or Thr-126 of the wild-type virus to Ser-126 or Asn-126 in three carriers and conversion from Gly-145 to Arg-145 in three of them; clones with Asn-126 or Arg-145 were found in one carrier. All 12 clones from the other carrier had an insertion of 24 bp encoding an additional eight amino acids between Thr-123 and Cys-124. In addition, all or at least some of the HBV DNA clones from these carriers had in-phase deletions in the 5' terminus of the pre-S2 region. These results indicate that HBV escape mutants with mutations in the S gene affecting the expression of group-specific determinants would survive in some carriers after they seroconvert to antibody against surface antigen. Carriers with HBV escape mutants may transmit HBV either by donation of blood units without detectable surface antigen or through community-acquired infection, which would hardly be prevented by current hepatitis B immuneglobulin or vaccines.

Adult↗
PubMed1994

Hypocomplementemia associated with hepatitis C viremia in sera from voluntary blood donors.

OBJECTIVES: Hepatitis C virus (HCV) infection induces extra-hepatic manifestations, most of which are considered to be mediated by circulating immune complexes. For evaluating this association in a wider perspective, complement activity was determined in sera from apparently healthy individuals, and hypocomplementemia was tested for correlation with HCV viremia. METHODS: Sera from 10,532 voluntary blood donors were stored at 4 degrees C overnight, serially diluted 2-fold, and tested for hemolytic activity by a microtitration method and antibody to HCV (anti-HCV) by passive hemagglutination with recombinant HCV antigens of the second generation. HCV RNA was determined in sera with anti-HCV or hypocomplementemia, or both, by polymerase chain reaction with nested primers deduced from the 5'-noncoding region of the HCV genome. RESULTS: Hypocomplementemia was detected in 53 (0.5%) of 10,532 donations and anti-HCV in 94 (0.9%). Anti-HCV was detected in 48 (91%) of the 53 sera with hypocomplementemia, more frequently than in 46 (0.44%) of 10,479 sera without (p < 0.001). Among 94 sera positive for anti-HCV, HCV RNA was detected in 45 (94%) of 48 sera with hypocomplementemia, more often than in 10 (22%) of 46 sera without (p < 0.001). CONCLUSIONS: A close association of hypocomplementemia with HCV viremia among apparently healthy blood donors would reflect circulating immune complexes which may cause extrahepatic diseases, such as cryoglobulinemia and membranoproliferative glomerulonephritis, in some HCV carriers. The storage of sera from HCV carriers at 4 degrees C before the test would have contributed to a decreased hemolytic activity due to the cold activation of complement by cryoglobulins involving HCV.

Adult↗