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Biomedical subjects

S Hige

Publications and source records attributed to S Hige.

At least 19 recordsLinked to original sources
PubMed1998

Prevalence of mutations in core promoter/precore region in Japanese patients with chronic hepatitis B virus infection.

We examined the frequency and significance of mutations in the core promoter and precore region in 103 Japanese patients with chronic hepatitis B virus (HBV) infection. HBV DNAs from the patients' sera were amplified by polymerase chain reaction and were directly sequenced. A double mutation (T1762 A1764) in the core promoter was frequently observed in the patients regardless of HBeAg status except for asymptomatic carriers with HBeAg. Furthermore, a mutation at nucleotide 1753 from T to C or G was frequently found in anti-HBe positive patients and was often accompanied by the double mutation. The A1896 mutation was found in only about one fourth of the patients with anti-HBe. These data suggest that the patients with chronic liver diseases frequently had a double mutation regardless of HBeAg status and a mutation at nucleotide 1753 might be associated with HBeAg-negative chronic hepatitis B virus infection.

Amino Acid Sequence↗
PubMed1998

Ten minute 13C-urea breath test for the diagnosis of Helicobacter pylori infection.

We investigated the utility of a 10-min 13C-urea breath test (13C-UBT) using 100mg of 13C-urea; this is a simple and rapid method for the detection of Helicobacter pylori infection. One hundred and fifty-one patients in whom the identification of H. pylori was established by rapid urease test, culture, and histology of six biopsy specimens underwent 254 13C-UBT examinations before and/or after eradication treatment. In the 133 patients who did not receive eradication treatment, the calculated sensitivity of the 10-min 13C-UBT was 99.4% and specificity 100% when the cut-off point was set at 3.5/1000, using a mass spectrometer. In the 121 patients who received eradication treatment, this cut-off point gave a sensitivity of 86.7%, a specificity of 99.1%, and a positive predictive value of 92.9%, with a negative predictive value of 98.1%. There were no significant differences between the diagnosis of H. pylori infection at 1 month and more than 3 months after the endpoint of eradication treatment. The 10-min 13C-UBT is suitable for the diagnosis of H. pylori infection before and after eradication treatment.

Breath Tests↗
PubMed1997

Differential flotation centrifugation study of hepatitis C virus and response to interferon therapy.

Hepatitis C virus (HCV) appears to circulate in various forms such as native virion, immune complexes, and nucleocapsids during chronic infections. To determine the association of the physicochemical properties of HCV and its response to interferon therapy in patients with chronic hepatitis C, we examined pretreatment serum samples from 43 patients with HCV RNA who had received interferon therapy, using differential flotation centrifugation in a NaCl solution with a density of 1.063 g/ml. After centrifugation, the ratio of HCV RNA in the top and bottom fractions was determined by the polymerase chain reaction and expressed as T/B. Patients with a sustained response to IFN therapy were found to have higher T/B ratios than transient responders who relapsed after treatment (P < 0.01) and nonresponders (P < 0.01). With regards to HCV genotypes, patients with genotype 1b had higher T/B ratios in the sustained response group than in the nonsustained response groups (P = 0.001), but patients with genotype 2 had a similar distribution of T/B among the 3 response groups (not significant). These findings indicate that the physicochemical properties of HCV affect the effectiveness of interferon therapy, particularly in patients with genotype 1b.

Adult↗
PubMed1996

Nucleotide sequences of the hepatitis C virus core region in patients without anti-core antibody.

Second-generation assays for detection of hepatitis C virus (HCV) infection that include reactivity of antibodies to core, NS3, NS4 are used because of their high sensitivity. Among these antibodies, anti-core antibody seems to be the most sensitive. However, there are some patients without anti-core antibodies, although HCV RNA is detectable by reverse transcription-polymerase chain reaction and branched DNA assay. The mechanism for the absence of anti-core antibody on its own is unclear. We therefore determined the nucleotide and deduced amino acid sequences of the core region obtained from two anti-core antibody-negative patients with HCV RNA (genotype 1b) and compared them with those of four anti-core antibody-positive patients and a previously reported sequence. Amino acids spanning 1-47, which seemed to exist in major B cell epitopes, were found to be completely conserved among these patients. Furthermore, the predictive binding motif to HLA DR4 (a.a 81-90) was completely conserved in both of the anti-core antibody-negative patients. There were various mutations in the residual amino acids spanning 49-108, but specific mutations could not be found in anti-core antibody-negative patients. These data indicate that the absence of anti-core antibody in two patients is not due to the presence of some formerly unknown viral variants, but due to a possible defect in the host's immune system.

Amino Acid Sequence↗
PubMed1996

Changes in hepatitis C virus quasispecies and density populations in patients before and after interferon therapy.

Some chronic hepatitis C patients show sustained response to interferon (IFN) therapy despite viremia. This condition seems to be related to the density populations of hepatitis C virus (HCV) [Kanto et al. (1995): J Med Virol 46:230-237]. To investigate further the relationship between alanine aminotransferase (ALT) levels after IFN therapy and the HCV density populations, we undertook differential flotation centrifugation of HCV and single strand conformation polymorphism targeted the hypervariable region (HVR) of E2 glycoprotein, which seems to be related to the density populations. Sera were obtained serially from 12 patients who had undergone IFN therapy (six sustained responders with viremia, six nonresponders). During the follow-up after interferon therapy, the HVR heterogeneities changed in 9 of the 12 patients. The remaining three patients whose heterogeneities did not changed persistently showed normal ALT. The changes in HVR heterogeneities were less pronounced in the sustained responders with viremia than in nonresponders; however, their density populations were prominently high in both responders. In two cases, changes in HVR heterogeneities and increase in low-density virion were observed before the hepatitis flare-up. These data indicate that HVR quasispecies show more relation to ALT levels after IFN therapy than HCV density populations and that the changes in the HVR sequences and HCV density populations may be associated with ALT elevation in some patients.

Adult↗
PubMed1994

[Classification of hepatitis C virus into two major groups in serologic activity: correlation with response to interferon].

Genotypes of HCV have been reported to be one of the predictors of response to IFN therapy in patients with chronic hepatitis C. HCV genotypes were determined enzyme-linked immunoblot assay based on group I and II specific recombinant peptides of the NS-4 region (amino acid No. 1676-1670). We examined the correlation between HCV groups and response to IFN in patients with chronic hepatitis C. Among the 84 patients with chronic hepatitis C who underwent IFN treatment, 16 of 51 (31.4%) patients with group I and 12 of 23 (52.2%) patients with group II showed complete sustained response. These results suggest that HCV group assay may improve the ability to predict IFN treatment outcomes.

Chronic Disease↗
PubMed1994

[Interstitial pneumonia induced by interferon therapy in type C hepatitis].

Interstitial pneumonia is known as one of the serious side effect of drugs. Recently, many investigators have reported that interstitial pneumonia (IP) which occurred during interferon (IFN) therapy for type C chronic hepatitis, and its appearance rate is considered to be more than 0.2% of patients who receive IFN. Though the mechanisms of IP during IFN therapy remains to be elucidated, one of the possible explanations is that excessive focal immune response in the lung derived from IFN might leads to the inflammation. For safe treatment, we must recognize that IFN induces IP during IFN therapy and give attention to its occurrence.

Adult↗
PubMed1994

[Clinical studies on the detection of hepatitis C virus genome in the serum and the liver].

Hepatitis C virus (HCV) is the major cause of non-A, non-B hepatitis worldwide. Since the HCV viral genome was molecularly cloned and antibody detection systems were established, a considerable amount of information on HCV has been accumulated. In the present study, I have examined the sera and liver tissues of the patients of type C chronic liver disease using molecular biological methods and tried to correlate the data obtained with the clinical, pathological and therapeutic outcomes. A reverse transcription-polymerase chain reaction (RT-PCR) method using radiolabeled nucleotides provided constant results in genome amplification, and could be shown to be a reliable method for quantifying the levels of HCV genome. The amount of HCV RNA in the serum tended to increase as a function of the duration of the disease and the progression of histopathologic changes of the liver. In addition, the serum HCV RNA titers correlated well with those of liver tissues, which showed that the amount of circulating HCV genome reflected the intrahepatic amount of HCV. HCV, a positive-stranded RNA virus, is likely to make a negative strand during viral replication. In studies to detect the positive and negative strands of HCV RNA separately using strand specific primers, the existence of both strands in the liver was demonstrated, confirming viral replication in the liver. The ratio of negative to positive strands ranged from 0.03% to 30%, being 3.7% in chronic persistent hepatitis, 4.8-6.0% in chronic aggressive hepatitis and 6.7% in liver cirrhosis. The viral factors influencing the interferon (IFN) response were also examined. Individuals who had low titers of HCV genome tended to respond well to IFN. Moreover, IFN was more effective for patients with HCV type III than for those with HCV type II. Thus, IFN response was shown to depend both on virus titers and genotypes. However, mean levels of HCV RNA were almost the same between the patients with HCV type II and those with HCV type III before the treatment, there were significant differences in the disappearance of HCV and the effects of IFN therapy. It is suggested that the susceptibility to IFN is different for each genotype. Hokkaido J Med Sci 69 (6), 1382-1398, 1994.

Adult↗
PubMed1994

Significance of 2',5'-oligoadenylate synthetase activity and HCV genotype in IFN therapy for type C chronic hepatitis.

Although the mechanisms of elimination of HCV by IFN have not been fully elucidated, the 2-5A system was reported to be one of the mechanisms of the anti-viral effect of IFN. Therefore, the relationship between HCV genotype, induction of 2-5AS and clinical effect was investigated. As for the anti-viral effect during IFN therapy, in type III or IV, most patients lost HCV-RNA regardless of serum 2-5AS induction even in high HCV-RNA concentration cases. In contrast, in type II, the negativity rate of HCV-RNA became high along with an increase of serum 2-5AS activity, but in patients with high HCV-RNA concentration, HCV-RNA was persistently positive. As for the long term clinical effect of IFN therapy judged 6 months after completion of IFN therapy, HCV genotypes were closely related to the effect; that is, the patients with type III or type IV HCV genotype showed a higher complete response rate compared with the patients with type II HCV genotype. However, the relationship between the long term clinical effects and induction of serum 2-5AS during IFN therapy was obscure. These results suggest that induction of 2-5AS is closely related to the anti-viral effect during IFN administration, but the viral factors appeared to be related to long term clinical effects after cessation of IFN therapy.

2',5'-Oligoadenylate Synthetase↗
PubMed1993

[Hepatitis C].

Hepatitis C virus (HCV) is a major cause of post transfusion non-A, non-B hepatitis. The virus contains a positive-strand RNA genome comprised of approximately 9,400 nucleotides. HCV E2/NS1 is probably an envelope glycoprotein (E2). The E2 hypervariable domain appears to contain isolate-specific antibody-binding linear epitopes. Recently, comparative sequence analysis of all the complete and partial HCV sequences published to date indicates that known genotypes of HCV can be classified into six basic groups. We report here that the prevalence of HCV-I, HCV-II, and a mixed form are 77.2%, 11.4%, and 11.4%, respectively. Patients with anti-HCV and HCV-RNA positive chronic active hepatitis received 6MU of interferon-alpha or beta everyday for two weeks followed by 6MU thrice a week for 14 weeks. Complete response to interferon treatment was defined as an ALT level normalized within six months after the end of treatment and maintained within the normal limit for an additional six months. Complete response was found in 42.9% of patients treated for 16 weeks. In a six month follow-up of the complete responders, clearance of viremia was observed in 90.3% at the end of interferon treatment and in 71.0% six months after the end of interferon treatment.

Chronic Disease↗