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Biomedical subjects

A Tsubota

Publications and source records attributed to A Tsubota.

At least 73 records · Page 4Linked to original sources
PubMed1996

A randomized, double-blind, controlled trial of natural interferon-beta therapy for e-antigen-negative chronic hepatitis B patients with abnormal transaminase levels.

Intermittent interferon (IFN) therapy appears to be effective for patients with e-antigen-negative chronic hepatitis B who exhibit abnormal fluctuations of alanine aminotransferase (ALT) levels and histological evidence of disease progression. To determine the optimal dose of IFN in such patients, we studied the effects of natural IFN-beta in a prospective, randomized, double-blind, controlled trial in 36 patients with e-antigen-negative chronic hepatitis B who repeatedly demonstrated abnormal fluctuations in ALT levels. Thirty-six patients were randomly assigned to three groups, receiving doses of: 0.3 MIU IFN (group 1; n = 12), 1 MIU (group 2; n = 12), or 3 MIU (group 3; n = 12), administered twice per week for 24 weeks. Patients were regarded as responders if ALT levels remained within the normal range and HBV-DNA tested negative for 6 months after the initiation of the therapy. According to this criterion, treatment was effective in 16.7% of the patients (2/12) in group 1, 33.3% (4/12) in group 2, and 75% (9/12) in group 3, the efficacy rate in group 3 being significantly higher than that in the other two groups. However, in 12 of the 15 responders, (80%) ALT levels were frequently elevated again within 3 years of the termination of IFN therapy. Although IFN was effective in controlling the manifestations of hepatitis in terms of e-antigen-negative patients who exhibited abnormal fluctuations in ALT, it appears that continuous treatment with intermittent high-dose IFN is necessary to maintain ALT levels within the normal range.

Adult↗
PubMed1996

Hepatitis C virus subtype 3b infection in a hospital in Japan: epidemiological study.

To elucidate the epidemiology of infection with hepatitis C virus (HCV) subtype 3b (a rare subtype thought to have originated in Southeast Asia) in Japan, we examined the genotypic subtype in 1397 patients with HCV-related chronic liver diseases. Of 1330 patients with identified HCV RNA genotypes. 960 had subtype 1b, 243 had subtype 2a, 97 had subtype 2b, 14 (1.1%) had subtype 3b, and 16 had other types of HCV or mixed subtypes. The age, gender, and severity of liver disease in patients with HCV subtype 3b did not differ from these features in patients with other subtypes. Eleven of the 14 patients with the 3b subtype had once worked at Company A in Tokyo, Japan. Multivariate logistic analysis showed that working history at that company was independently associated with the incidence of the subtype; the risk ratio was 207.2 (P < 0.0001). All 11 patients from Company A had received medical services, between 1953 and 1981, at Clinic C, which undertook medical care of the company staff. All 11 patients had received repeated intramuscular or intravenous injections for treatment of various diseases or for preventive vaccination for contagious diseases. The rare HCV subtype 3b, appeared to have been transmitted among the employees of a company through the performance of certain medical practices.

Adult↗
PubMed1996

A pilot study of corticosteroid priming for lymphoblastoid interferon alfa in patients with chronic hepatitis C.

Interferon treatment reduces the serum level of hepatitis C virus (HCV) and improves inflammatory activity, but relapse is frequently observed. In an attempt to develop a new therapeutic strategy that may reduce relapse and cure the disease, we evaluated the effect of corticosteroid priming on lymphoblastoid interferon alfa in an open randomized clinical trial. The level of HCV RNA increased significantly during corticosteroid priming (from 5.60 [median] to 21.0 x 10(5) Eq/mL; P = .0004) but decreased to the pretreatment level 4 weeks after cessation of corticosteroid (7.0 x 10(5) Eq/mL; P = .07). Sustained normalization of alanine transaminase (ALT) level and virus clearance, confirmed by negative results for HCV RNA using reverse-transcription nested polymerase chain reaction (PCR), were observed over a period of 6 months in 8 of 19 (42.1%) corticosteroid-primed patients, compared with 6 of 19 patients (31.6%) treated with interferon only. A "rebound" of ALT after the withdrawal of corticosteroid was observed in only 2 of 19 patients primed with corticosteroid, but both showed sustained responses. Multivariate analysis for factors predictive of the sustained response indicated that HCV titers measured immediately before interferon therapy and HCV genotype were statistically significant (P = .006 and P = .025, respectively). Our results indicated that corticosteroid priming has a marginal benefit over treatment with interferon alone and that large-scale clinical trials are necessary to determine whether interferon with corticosteroid priming is more effective than interferon alone.

Adult↗
PubMed1995

Diagnosis of hepatocellular carcinoma by concanavalin A affinity electrophoresis of serum alpha-fetoprotein.

BACKGROUND: Concanavalin A (Con A) affinity electrophoresis of serum alpha-fetoprotein (AFP) can distinguish hepatocellular carcinoma (HCC) from other malignancies when the serum AFP concentration is elevated. However, Con A has not been able to distinguish HCC from benign chronic liver disease such as cirrhosis or chronic hepatitis. METHODS: The Con A affinity electrophoresis of serum AFP was analyzed in patients with a serum AFP concentration greater than 50 ng/mL by antibody affinity electrophoresis and Western blotting in an attempt to distinguish hepatocellular carcinoma from benign chronic liver disease. Before the assay, the serum AFP concentrations were adjusted between 100 ng/ml and 300 ng/ml by concentrating or diluting the samples. RESULTS: Of 180 patients with HCC, 44 (24%) had a single band and 91 (51%), 35 (19%), and 10 (6%) had 2, 3, and 4 bands, respectively. All 35 patients with chronic hepatitis had a single band. All but 1 of 72 patients with cirrhosis had a single band. Multiple AFP bands on Con A affinity electrophoresis appear to be diagnostic of HCC. This method has a sensitivity of 76%, a specificity of 99%, a positive predictive value of 99%, and a negative predictive value of 71% for detecting HCC. The number of AFP bands correlated with serum AFP concentration and tumor size in patients with HCC. CONCLUSIONS: This assay is useful for distinguishing HCC from benign chronic liver diseases.

Adult↗
PubMed1995

Genotype, slow decrease in virus titer during interferon treatment and high degree of sequence variability of hypervariable region are indicative of poor response to interferon treatment in patients with chronic hepatitis type C.

In a study assessing factors associated with a good or a poor response to interferon treatment in patients with chronic hepatitis type C, we analyzed serum samples taken from 26 interferon-treated patients and found further evidence that infection with genotype II is associated with a poor response. Whereas all seven patients with group III genotype tested showed a good response (normalization of alanine aminotransferase level for more than 6 months), only 10 of 19 (53%) patients infected with group II genotype showed a good response. We also observed that 16 of 17 (94%) patients who exhibited a rapid virus titer decrease during the first 2 weeks of treatment later showed a good response. In contrast, only three of nine (33%) patients with an initially slow viral decrease eventually showed a good response (p<0.04). None of the 26 control patients exhibited a marked virus decrease or normalization of serum alanine aminotransferase level. Interestingly, high degrees of sequence variability were seen in three patients with group II hepatitis C virus who responded poorly to the therapy. All three showed slow decreases in virus titer during the first 2 weeks of treatment. In contrast, patients with genotype II who showed a good response to treatment were seen to have very few mutations. In three patients with genotype III who had responded well to interferon treatment, all showed very little amino acid sequence variability in the hypervariable region compared with patients with genotype II who had responded poorly to interferon treatment. These data suggest that a slow decrease in virus titer during the beginning of interferon treatment and a high degree of sequence variability, both of which are often seen in patients with group II genotype, are associated with poor response to interferon treatment.

Adult↗
PubMed1995

Molecular analysis of intraspousal transmission of hepatitis C virus.

BACKGROUND/AIMS: Although intraspousal transmission of hepatitis C virus (HCV) has been speculated, there is no direct evidence. METHODS: To investigate whether transmission of HCV occurs by this route, 295 spouses of persons diagnosed with HCV were studied. Of these, 25 (8.8%) tested positive for anti-HCV. Next, the HCV genotype was determined by polymerase chain reaction using a mixed primer set, and cDNA was obtained in 17 of the 25 couples for comparison of the genotypes. RESULTS: Of these 17, 14 (82.4%) spouses were shown to be infected with HCV of the same genotype. Analysis of the nucleotide sequences of putative E1 gene of eight couples having the same HCV genotype revealed that five couples had remarkably high nucleotide sequence homologies (> 97%), whereas samples obtained from the remaining three couples showed relatively low homology (91-92%). Nucleotide sequence homologies were significantly higher between spouses than between non-spouse pairs of isolates. Phylogenetic analysis using the neighbor-joining method suggests that infection in these five couples probably occurred after marriage. Furthermore, none of the five couples had shared other possible transmission routes such as intravenous drug use, dental treatment or acupuncture. CONCLUSION: These data strongly suggest the occurrence of intraspousal transmission of HCV.

Adult↗
PubMed1995

A prospective randomized evaluation of a compound of tegafur and uracil as an adjuvant chemotherapy for hepatocellular carcinoma treated with transcatheter arterial chemoembolization.

A prospective randomized trial was conducted to evaluate the efficacy of long-term oral administration of low-dose tegafur combined with uracil as an adjuvant chemotherapy, following transcatheter arterial embolization (TAE) in 40 patients with hepatocellular carcinoma (HCC). Forty eligible patients were randomized into two groups: 20 with TAE plus UFT (a compound of tegafur 200 mg and uracil 448 mg per day) and 20 with TAE alone. A good necrosis rate or decrease in size of more than 70% of the original tumor mass was attained in 10 by TAE plus UFT arm and in 12 by TAE arm alone. As for the "responded" patients, there was no significant difference in the time from tumor response to tumor regrowth between the two groups. The appearance rate of ascites and/or encephalopathy in patients with chemotherapy was slightly higher than that in control patients. The median survival time was 22.7 months for TAE plus UFT arm and 28.2 months for TAE arm alone. There was no significant difference in the cumulative survival curves. In conclusion, these results indicated no substantial benefit for this chemotherapy regimen, as an adjuvant therapy for patients with HCC during repeated TAE.

Adult↗
PubMed1995

Serial hemodynamic measurements in well-differentiated hepatocellular carcinomas.

We performed serial hemodynamics in 15 patients with 21 well-differentiated hepatocellular carcinomas. The total length of the observation period ranged from 129 to 678 days (median, 368). We investigated both arterial and portal blood flow at intervals of at least 4 months. Arterial blood flow was measured with carbon dioxide-enhanced ultrasonography (US), and portal blood flow was measured with computed tomographic arterial portography (CTAP). None of the tumors were hypervascular on the initial study; however, by the final study nine nodules (42.9%) had become homogeneously hypervascular, two (9.5%) had become partially hypervascular, and the others did not change. Of 10 nodules without portal blood supply on any study, 8 became hypervascular by the final study. Of 11 nodules with portal blood supply on the initial study, a follow-up study showed no change in portal flow in 6 and the loss of portal flow in 5. Four of these five became hypervascular, with a documented loss of portal flow before the increase in arterial flow. The doubling time of tumors with a homogeneous increase in arterial blood flow ranged from 89 to 333 days (median, 172), whereas the doubling time of other tumors ranged from 227 to 607 days (median, 392). Thus, growth rate and vascularity in well-differentiated hepatocellular carcinoma are closely correlated. When the well-differentiated hepatocellular carcinoma has portal blood flow and is not hypervascular, it grows slowly. On the other hand, when it loses portal blood flow and becomes hypervascular, it grows rapidly.

Adult↗
PubMed1994

Serum des-gamma-carboxyprothrombin concentration determined by the avidin-biotin complex method in small hepatocellular carcinomas.

BACKGROUND: Des-gamma-carboxyprothrombin (DCP) is a useful tumor marker for hepatocellular carcinoma (HCC). The present method for measurement of DCP concentration, however, does not have adequate sensitivity to detect small HCCs. METHODS: The serum DCP concentration was investigated by the avidin-biotin complex (ABC) method in patients with an HCC smaller than 20 mm in maximum dimension. A serum DCP concentration greater than 4.0 arbitrary units per liter using the ABC method was considered abnormal. RESULTS: Of 115 patients with small HCC, 45 (39.1%) had an abnormal DCP concentration. Ten of 141 patients with chronic hepatitis (7.1%), 18 of 115 (15.7%) with cirrhosis, and 0 of 30 normal control patients had abnormal DCP concentrations. This method yielded a sensitivity of 39.1%, a specificity of 89.1%, a positive predictive value of 61.6%, and a negative predictive value of 76.5% for detection of small HCC. The detectability of HCC increased to 56.5% when alpha-fetoprotein (AFP) was was measured (> 40 ng/ml). Abnormal DCP concentrations were seen in 8 of 34 (23.5%), 24 of 42 (57.1%), and 5 of 7 (71.4%) patients with Edmondson's Grade I, II, and III tumors, respectively. There was a significant relationship between DCP concentrations and histologic grade (P = 0.0017), but there was no association between DCP concentration and other patient characteristics. Elevation of serum AFP concentrations in patients with hepatitis B surface antigen positivity, however, was more frequent than that in patients who were antihepatitis C virus (HCV) positive. Therefore, the measurement of serum DCP concentrations may be more useful than that of serum AFP concentrations in patients with anti-HCV positivity. CONCLUSIONS: The measurement of serum DCP concentrations by the ABC method is a useful diagnostic tool for the monitoring of small HCC.

Adult↗
PubMed1994

Interferon retreatment of nonresponders with HCV-RNA-positive chronic hepatitis C.

Interferon has been shown to be an effective treatment for some patients with chronic hepatitis C. In this study, the value of retreatment of nonresponders to interferon was investigated. Thirty-eight patients with hepatitis C virus (HCV)-RNA-positive chronic hepatitis C who had been treated with beta-interferon but still showed an alanine aminotransferase (ALT) level > 50 KU upon completion of therapy were retreated with alpha-interferon. Eight patients (21.1%) had normalization of ALT levels for at least 6 months after the completion of retreatment. The factors related to normalization of ALT levels after interferon retreatment were studied. Of 16 patients with transient HCV-RNA negativity 1 month after the initial interferon therapy, 7 (43.8%) had a complete response, with normalization of ALT levels and undetectable HCV-RNA, more than 6 months after interferon retreatment. On the other hand, of the 22 patients with HCV-RNA activity 1 month after the initial interferon therapy, only 1 (4.5%) had a complete response. Multivariate analysis, using a multiple logistic model, indicated that a complete response to readministration of interferon was most strongly correlated to transient negative conversion for HCV-RNA after the initial course of treatment.

Alanine Transaminase↗
PubMed1994

Prevalence of HCV genotype among patients with chronic liver diseases in the Tokyo metropolitan area.

We examined 613 Toranomon Hospital patients with HCV RNA-positive chronic liver disease to elucidate the viral genotype in the Tokyo metropolitan area. An epidemiological and clinical study was conducted in the 565 patients whose HCV genotype could be determined. The HCV genotypes found were type II, in 414 patients (67.5%); type III, in 103 (16.8%); type IV, in 37 (6.0%); type V, in 4 (0.7%); mixed genotype II and III, in 5 (0.8%); and mixed genotype II and IV, in 2 (0.3%). The HCV genotype could not be determined in 48 patients. Type II was most prevalent. The HCV genotype I was not found at all. There were no significant differences between genotypes in relation to sex, age, history of blood transfusion, or the progression of the disease. It was uncommon to find a history of blood transfusion in the patients with mixed genotypes; however, a high incidence of hepatic disorders was noted among the family members of these patients. Ninety-two percent of the patients with HCV genotype II tested positive for C100-3, while 70.9% of those with type III, and 43.2% of those with type IV tested positive for this antibody. HCV genotype II was most prevalent, and the positivity rate for anti C100-3 in patients with this HCV genotype was significantly higher (P < 0.00001) than that in patients with the other genotypes.

Adolescent↗
PubMed1994

A detection method for point mutation in the precore region of human hepatitis B virus (HBV)-DNA using mutation-site-specific assay.

In the natural progression of acute active hepatitis and chronic active hepatitis in human hepatitis B virus (HBV)-infected patients, inactive hepatitis develops by seroconversion, which can be explained by the disappearance of HBe antigen. However, it has been found that in some patients with hepatitis, alanine aminotransferase levels undergo fluctuation even though their serum is negative for HBe antigen. In these patients, HBV-DNA has been detected in the serum and the HBV-DNA so detected has been considered a cause of worsening liver function. Most HBV-DNA detected in these cases has a point mutation from G to A at the 83rd base in the precore region. As a result of this point mutation, HBV is unable to produce HBe antigen. We have devised a sensitive polymerase chain reaction (PCR) method, a mutation-site-specific assay, for the detection of point mutations at the 83rd base in the precore region using a specific mutation-trapped oligonucleotide primer for the mutant HBV genome.

Base Sequence↗
PubMed1994

Imaging diagnosis of small hepatocellular carcinoma.

To elucidate the detectability of small hepatocellular carcinoma by various imaging modalities, we performed digital subtraction angiography, computed tomographic arterioportography and carbon dioxide-enhanced ultrasonography. Of 76 patients with a small hepatocellular carcinoma of 2 cm or less in maximum diameter, 61 underwent digital subtraction angiography, computed tomographic arterioportography and enhanced ultrasonography at the same time. Concerning the 61 patients undergoing all the procedures, the characteristics of hepatocellular carcinoma were found in 57.4% (35 of 61) by digital subtraction angiography, 75.4% (46 of 61) by computed tomographic arterioportography and 72.1% (44 of 61) by enhanced ultrasonography. Among them, four hepatocellular carcinomas were detected only by enhanced ultrasonography, three were diagnosed only by computed tomographic arterioportography and two were diagnosed by both of them. Except for six hemangioma nodules that were easily diagnosed only with angiography, four of 55 benign hepatic nodules (7.3%) showed false-positive findings suggestive of hepatocellular carcinoma with either computed tomographic arterioportography or enhanced ultrasonography. In conclusion, computed tomographic arterioportography and enhanced ultrasonography could complementarily detect a small hepatocellular carcinoma more sensitively than digital subtraction angiography.

Adult↗
PubMed1994

Nucleotide sequence of hepatitis C virus (type 3b) isolated from a Japanese patient with chronic hepatitis C.

The genomic sequences of many hepatitis C virus (HCV) isolates have been reported and a variety of virus genotypes have been classified based on homology in the conserved regions. We have previously identified five distinct genotypes (1a, 1b, 2a, 2b and 3b) in Japanese patients with chronic HCV infection by comparing the sequences of the NS5 region. The complete nucleotide sequence for five genotypes (1a, 1b, 1c, 2a and 2b) have already been reported and we report here the complete nucleotide sequence of genotype 3b. The isolate (HCV Tr) was 9439 nucleotides long, excluding the poly(U) tract at its 3' end, and encodes a single long open reading frame of 3023 amino acids. Total nucleotide sequence homologies were 68.4 to 68.7%, 68.3 to 69.0%, 67.2%, 65.8% and 65.6% compared with type 1a, 1b, 1c, 2a and 2b genomes, respectively. The amino acid sequences of these five genotypes were highly homologous in the core, NS3 and NS5B regions, but the E2/NS1 region, which contains hypervariable regions 1 and 2, and the NS5A region were poorly conserved. Although it was possible to detect antibody against the relatively homologous core and NS3 regions by ELISA, the presence of divergent protein structures must be taken into account in the development of a vaccine.

Amino Acid Sequence↗