Search PubMed⌕ Search

Biomedical subjects

F Tsuda

Publications and source records attributed to F Tsuda.

At least 55 records · Page 3Linked to original sources
PubMed1996

Reduced precore transcription and enhanced core-pregenome transcription of hepatitis B virus DNA after replacement of the precore-core promoter with sequences associated with e antigen-seronegative persistent infections.

Hepatitis B virus variants harboring nucleotide alterations in the preC-C promoter have been detected in fulminant hepatitis B as well as in HBeAg-seronegative persistent infection. However, it has not been demonstrated that variants with nucleotide alterations in the preC-C promoter cause various disease states. We replaced the preC-C promoter region of a wild-type genome with the most frequent naturally occurring mutated form and introduced it into HepG2 cells. The mutant with coexisting A1762T and G1764A substitutions produced less than one-fifth of the wild-type level of HBeAg. Conversely, the mutant generated 2.4 times more core particle antigen and showed a high-replicator phenotype. RNase protection and quantitative 5' RACE showed a 16- to 32-fold reduction of preC transcripts and a 4-fold induction of C transcripts of the mutant compared to wild-type. The preC transcript of the mutant had a more heterogeneous 5' end than that of the wildtype. However, the mutations did not alter the initiation sites of C transcription. When the promoter region was cloned into CAT plasmids, the mutations had dual effects on preC and C promoter activities, decreasing and increasing them, respectively. These results suggest that these mutations are responsible for the reduced HBeAg production as well as the enhanced replication and core production. Analysis of revertants with either single point mutation showed that T at 1762 is critical for the mutant phenotype.

Amino Acid Sequence↗
PubMed1996

Infection with hepatitis GB virus C in patients on maintenance hemodialysis.

BACKGROUND: A recently discovered non-A-E hepatitis virus has been designated hepatitis GB virus C (HGBV-C), but little is known about its mode of transmission and its clinical manifestations. We studied 519 patients on maintenance hemodialysis to determine whether they were infected with HGBV-C. METHODS: HGBV-C RNA was identified in serum by a reverse-transcription-polymerase-chain-reaction assay with nested primers deduced from a non-structural region. A nucleotide sequence of 100 bp in the nonstructural region was determined on HGBV-C clones. RESULTS: HGBV-C RNA was detected on 3.1 percent of the patients on hemodialysis (16 of 519), as compared with 0.9 percent of healthy blood donors (4 of 448, P<0.03). None of the 16 patients had evidence of active liver disease, although 7 were also infected with hepatitis C virus. Eight patients with HGBV-C infection were followed for 7 to 16 years. In two patients the virus was present at the start of hemodialysis. One had a history of transfusion, and HGBV-C persisted over a period of 16 years; the other became free of HGBV-C after 10 years. In five patients, HGBV-C RNA was first detected 3 to 20 weeks after blood transfusion and persisted for up to 13 years. One patient with no history of transfusion was infected with an HGBV-C variant with the same sequence as in two of the patients with post-transfusion HGBV-C infections. CONCLUSIONS: Patients on maintenance hemodialysis are at increased risk for HGBV-C infection. This virus produces persistent infections, which may be transmitted by transfusions but may also be transmitted by other means.

Adult↗
PubMed1996

Infection with GB virus C in leprous patients in Japan.

The detection of hepatitis C virus (HCV) in blood donors and patients with acute and chronic hepatitis has brought to the fore another virus or viruses which can be transmitted parenterally and induce liver disease. The RNA of a candidate virus designated GB virus C (GBV-C) was determined by the polymerase chain reaction with primers deduced from a helicase-like region in 229 leprous patients in Japan. GBV-C RNA was detected in 12 (5.2%) patients, and HCV RNA in 41 (18%). Three patients were coinfected with GBV-C and HCV. The nine patients infected with GBV-C alone had aminotransferase levels lower than the three patients with the mixed infection or the 38 patients infected with HCV only (P < 0.001). Sequence comparison within 100 base pairs in the helicase-like region suggested that two, three and three patients, respectively, would have been infected with three distinct strains of GBV-C. These results indicate that patients with leprosy are at increased risk for infection not only with HCV, but also with GBV-C, and that the infection with GBV-C alone would not induce hepatic injuries as severe as HCV infection.

Adult↗
PubMed1996

Infection with GB virus C (GBV-C) in patients with chronic liver disease or on maintenance hemodialysis in Indonesia.

RNA of a non-A to E hepatitis virus identified recently and designated provisionally GB virus C(GBV-C), was sought in patients in Indonesia by reverse-transcription polymerase chain reaction with nested primers deduced from a helicase-like region. GBV-C RNA was detected in 32 (55%) of 58 patients on maintenance hemodialysis at a frequency significantly higher (P < 0.001) than that in seven (5%) of 149 patients with chronic liver disease. Co-infection with hepatitis C virus was observed in 26 (81%) of the 32 patients on hemodialysis and in five (71%) of the seven patients with liver disease who were infected with GBV-C. Complete identity was observed in a sequence of 100 base pairs in the helicase-like region for GBV-C cDNA clones from some patients on maintenance hemodialysis. These results indicate that the patients on hemodialysis would be at high risk for GBV-C infection, which would be transmitted by transfusion and patient-to-patient routes.

Antigens, Viral↗
PubMed1996

HLA DRB1 and DQB1 alleles and haplotypes influencing the progression of hepatitis C.

Some HLA class II alleles and haplotypes were examined by restriction fragment length polymorphism of corresponding DNA fragments amplified by the polymerase chain reaction in 117 patients with chronic hepatitis C in Japan. The prevalence rates were compared between patients and 1216 controls and in 67 patients with liver cirrhosis, of whom 20 had hepatocellular carcinoma and 50 patients with chronic hepatitis who did not have cirrhosis or hepatocellular carcinoma. Notably, DRB1*0405 (49% [95% confidence range 38-60%] vs. 26% [16-40%]; P < 0.05, relative risk [rr] = 2.8) and DQB1*0401 (43% [33-54%] vs. 22% [13-34%]; P < 0.05, rr = 2.1) were detected more frequently in patients with cirrhosis than in those without cirrhosis. By contrast, DRB1*0901 (11% [6-19%] vs. 28% [18-40%]; P < 0.05; rr = 0.3) and DQB1*0303 (11% [6-19%] vs. 36% [25-49%]; P < 0.01; rr = 0.2) were detected less frequently in patients with cirrhosis than those without cirrhosis. Accordingly, the DRB1*0405-DQB1*0401 haplotype was more common (43% [33-54%] vs. 22% [13-34%]; P < 0.05; rr = 2.7), while the DRB1*0901-DQB1*0303 haplotype was less common (9% [4-17%] vs. 28% [18-40%]; P < 0.05; rr = 0.3) in patients with cirrhosis than in those without cirrhosis. These results suggest that there would be HLA class II alleles and haplotypes which may be associated with an accelerated or slower progression of chronic hepatitis C towards cirrhosis and eventually to hepatocellular carcinoma.

Alleles↗
PubMed1996

Prevalence of hepatitis C virus and distribution of its genotypes in Northern Eurasia.

We tested hepatitis C virus (HCV) antibody in 4216 sera collected from healthy people living in European part of Russia (including Northern, North-Western, Central, Central-Blacksoil, Volga-Vyatka, Volga, and North-Caucasian regions), non-European part of Russia (the Urals, East-Siberia, and the Far-East regions) and Mongolia. Prevalence of HCV antibody varied significantly by regions, ranging from 0.7% in Central region of European part of Russia to 10.7% in Mongolia. Genotyping of HCV (into 1a, 1b, 2a, 2b, and 3a) was performed on 469 sera from blood donors and patients (in Russia, Moldova, Turkmenistan, and Mongolia) who were positive for both HCV antibody and RNA. Genotype 1b was the most dominant genotype irrespective of regions (68.9%), with the highest rate in Moldova (96%). HCV unclassifiable into genotypes 1a-to-3a was found in 28 (6.0%) samples: particularly 4 of 10 samples from Lipetzk were untypable. Overall, HCV genotypes in European part of Russia were more similar to those in European countries, while those in Eastern part of Russia more similar to China or Japan. Genotype distribution was not associated with the clinical expression of HCV disease: acute hepatitis, chronic hepatitis or liver cirrhosis.

Adult↗
PubMed1996

Hepatitis C virus antibody, viral RNA and genotypes in leprous patients in Japan.

BACKGROUND/METHODS: Markers of hepatitis C virus infection were tested for in 229 patients with leprosy (male 154, female 75) in Japan. RESULTS: Antibody to hepatitis C virus by a second-generation enzyme immunoassay was detected in 68 patients (30%), and RNA of hepatitis C virus in 41 (18%), in prevalence rates much higher (p < 0.001) than those in matched controls (11/923 or 1.2% and 9/923 or 1.0%, respectively). Hepatitis C virus genotypes were II/1b in 37 (90%), III/2a in three (7%) and IV/2b in one (2%), in which II/1b was more frequently (p < 0.003) represented than in hepatitis C virus carriers without leprosy in Japan (520/767 or 68%). The 41 patients with hepatitis C virus viremia had serum transaminase levels significantly higher than those in the other 188 patients without viremia (p < 0.01). CONCLUSIONS: These results indicate that leprous patients confined in institutions are at high risk of hepatitis C virus infection, and that patients infected with hepatitis C virus should be monitored for liver function and placed on interferon therapy whenever required.

Biomarkers↗
PubMed1996

Infection with GB virus C (GBV-C) in patients with fulminant hepatitis.

BACKGROUND/METHODS: There appear to be hepatitis viruses other than hepatitis A, B, C, D and E. One of these has been proposed with a designation of GB virus C. Sera from 44 patients with fulminant hepatitis were tested for RNA of GB virus C by reverse-transcription polymerase chain reaction with nested primers deduced from the putative non-structural 3 (helicase) region. RESULTS: RNA of GB virus C was detected in three (20%) of 15 patients with hepatitis B virus infection and three (12%) of 25 patients without markers of hepatitis A-E virus infection. Overall, GB virus C RNA was detected in six (14%) of the 44 patients with fulminant hepatitis, at a frequency significantly higher (p < 0.001) than that in three (0.9%) of 326 blood donors matched for age with the patients. CONCLUSIONS: These results indicate a role of GB virus C in inducing fulminant hepatitis either by itself or in concert with the other hepatitis viruses.

Acute Disease↗
PubMed1996

Hepatitis C virus infection in patients with urticaria.

BACKGROUND: Hepatitis C virus (HCV) infection induces variable skin manifestations. OBJECTIVE: Our purpose was to determine whether there is an association between HCV infection and urticaria. METHODS: Antibody to HCV (anti-HCV) and HCV genotypes were determined in patients with urticaria and in a control population. RESULTS: Anti-HCV was detected in 19 (24%) of 79 patients with urticaria, and HCV RNA was detected in 17 (22%). Genotypes of HCV were II/1b in 12 (71%), III/2a in 4 (24%), and IV/2b in 1 (6%). The 17 patients with HCV RNA were older (53 +/- 14 vs 41 +/- 14 years, p < 0.01), and their eruption lasted longer (35% vs 6%, p < 0.05) and left pigmentation more frequently (53% vs 3%, p < 0.001). They had higher levels of alanine aminotransferase (67 +/- 34 vs 25 +/- 17 U/L, p < 0.001), aspartate aminotransferase (51 +/- 23 vs 21 +/- 8 U/L, p < 0.001), zinc turbidity test (12.8 +/- 3.1 vs 9.3 +/- 3.7 Kunkel units, p < 0.001), and IgG (1919 +/- 320 vs 1622 +/- 349 mg/100 ml, p < 0.01) than the patients without HCV RNA. CONCLUSION: HCV could be a significant cause of urticaria. Chronic urticaria associated with HCV infection has peculiar clinical, serologic, and biochemical characteristics that could make it a distinct clinical entity with an indication for interferon therapy.

Adolescent↗
PubMed1996

Hepatitis C virus variants from Jakarta, Indonesia classifiable into novel genotypes in the second (2e and 2f), tenth (10a) and eleventh (11a) genetic groups.

Hepatitis C virus (HCV) isolates from 126 hepatitis patients in Jakarta, Indonesia were genotyped by PCR with genotype-specific primers deduced from the HCV core gene. Fifty-five isolates (44%) were classified as genotype II/1b, 15 (12%) as 1c, 33 (26%) as III/2a, and 1 (1%) as V/3a, while the remaining 22 (17%) were not classifiable into any of the five common genotypes (I/1a, II/1b, III/2a, IV/2b and V/3a) or 1c. Sequences of a part of the NS5b region [1093 bp (nucleotides 8279-9371)] of the 22 isolates of unclassifiable genotype were subjected to pair-wise comparison and phylogenetic analysis along with those of 62 isolates of 25 genotypes in nine genetic groups. Seven of the isolates were classified into 2e and two into 2f, representing novel genotypes in genetic group 2, while ten and three were classified into two new genetic groups, 10 and 11, respectively, and their genotypes were provisionally designated 10a and 11a. The isolates of genotype 10a (JK049) and 11a (JK046) were sequenced in full. Comparison of 24 HCV genomes including those of JK049 and JK046, over the entire genome and subgenomic regions, supported the classification of HCV into 11 genetic groups.

Amino Acid Sequence↗
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

Genotypes and multiple infections with hepatitis C virus in patients with haemophilia A in Japan.

Hepatitis C virus (HCV) RNA was tested for, and HCV genotypes determined, in 96 patients with haemophilia A in Japan. Of 88 patients aged > or = 10 years, 74 (84%) were positive for HCV RNA at a frequency higher than that in patients aged less than 10 years (one of eight, 13%, P < 0.001). Genotype I/1a was detected in 30(40%), II/1b in 12 (16%), III/2a in eight (11%), IV/2b in five (7%) and V/3a in 12 (16%); mixed infection with HCV of two different genotypes was identified in the remaining nine (12%). This distribution was markedly different from that in 767 Japanese HCV carriers without haemophilia, in whom II/1b accounted for the majority (68.7%), I/1a was rare (0.5%), V/3a was absent, and mixed infection was observed rarely (1.3%). Mixed infection was transient in all of the seven haemophilic patients who were followed for 1 to 7 years. One of them was infected with genotype II/1b and an unclassifiable genotype, which showed nucleotide sequence similarity to genotype 4c from Zaire (82% homology in the E1 gene) and to 4a from Egypt (91% homology in a part of the NS5b region). In this patient, HCV of genotype II/1b disappeared while that of group 4 survived during a 4-year observation period. These results indicate different epidemiology of HCV genotypes in Japanese haemophiliacs, attributable to HCV contaminating factor VIII imported in the past, and an increased opportunity in haemophiliacs for mixed infection with HCV of different genotypes.

Adolescent↗
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↗
PubMed1996

[High prevalence of hcv infection in a town where high mortality from liver disease is observed].

It was recognized that the mortality rate from chronic liver diseases in town T was greater than 2 times the average for other areas of Miyazaki Prefecture. A seroepidemiological survey of the hepatitis viral markers, such as, HBs antigen (RPHA method) and CP antibody (EIA method) an HCV core antibody, was conducted among 7,178 residents both in town T and in its neighboring town Y. There was no difference in the rates of HBs antigen positives between town T (1.1%) and town Y (0.9%). However, the rates of CP antibody positives were 23.7% and 2.7% in town T and town Y, respectively. The former was significantly higher than the latter (p < 0.001, Chisquare test). CP antibody positives are more likely to have abnormal liver function than negatives. These results clearly suggest that the rate of the residents with abnormal levels of liver function in town T was significantly higher than in town Y. Of 33 people who had a history of acute hepatitis in 1972, 30 tested positive for CP antibody. An epidemic of acute hepatitis in 1972 is speculated to have been caused by HCV infection, which in turn may account for the higher incidence of liver disease mortality in town T.

Adolescent↗
PubMed1996

Core promoter mutations of hepatitis B virus for the response to interferon in e antigen-positive chronic hepatitis B.

OBJECTIVES: Mutations in the precore region are not always detected in hepatitis B virus (HBV) from patients with chronic hepatitis B who respond to interferon and lose hepatitis B e antigen (HBeAg) from serum. The other mutations may also be responsible for the loss of HBeAg and response. METHODS: Forty six consecutive patients with HBeAg-positive chronic hepatitis B received recombinant-alpha 2 a interferon (total dose: 702 MU). The mutation for stop codon 28 in the precore region was determined by restriction fragment length polymorphism, and mutations in the core promoter were searched for in five HBV DNA clones propagated from each patient. RESULTS: HBeAg was cleared at 6 months after interferon in 11 (61%) of 18 patients with the precore mutation and in 12 (43%) of 28 without it. Of these 28 patients, 19 with mutations in the core promoter in all five HBV DNA clones lost HBeAg more frequently than the remaining nine who had at least one clone among the five that lacked such mutations (58 vs 11%, p < 0.05). CONCLUSIONS: HBeAg-positive patients infected with HBV variants having mutations for an HBeAg-negative phenotype would respond better to interferon by clearing HBeAg from serum. Such mutations may not necessarily be in the precore region but also in the core promoter, which would interfere with the synthesis and secretion of HBeAg either at the translation or transcription level.

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↗