PubMed Health⌕ Search

Biomedical subjects

Fumio Imazeki

Publications and source records attributed to Fumio Imazeki.

At least 19 recordsLinked to original sources
PubMed2006

Analysis of genes upregulated by the demethylating agent 5-aza-2'-deoxycytidine in gastric cancer cell lines.

In gastric cancer, increasing numbers of genes have been reported to be silenced by aberrant methylation. However, global analysis of epigenetic inactivation in cancer cells has rarely been performed. For screening the genes upregulated by the demethylating agent 5-aza-2'-deoxycytidine (DAC), cDNA microarray analysis (AceGene(R), containing 30,000 genes) was performed using gastric cancer cell lines (AGS, MKN74, MKN1, MKN45 and Kato3) treated with DAC. The candidate upregulated genes were confirmed by real-time PCR, and the methylation status of 5'CpG islands was determined by bisulfite DNA sequencing or methylation-specific PCR. Among the upregulated genes considered to have CpG island in their promoter regions, we selected 5 genes (BCL2L10, DKK1, DNAJD1, GAGED2 and NMU) that exhibited a greater than 3-fold increase in at least 2 cell lines. Of these, we could determine the methylation status of 5'CpG islands of BCL2L10, DKK1 and DNAJD1. 5'CpG of BCL2L10 and DNAJD1 was hypermethylated in 4 of 5 gastric cancer cell lines, whereas 5'CpG of DKK1 was hypermethylated in only 1 cell line. MSP analysis for BCL2L10 revealed that the CpG island was demethylated after DAC treatment. In addition, we observed that overexpression of BCL2L10 could promote apoptosis and growth-inhibitory effect in gastric cancer cell lines. In conclusion, some of the genes upregulated by DAC treatment may be transcriptionally repressed by promoter hypermethylation. These genes might be related to gastric carcinogenesis. In particular, the suppression of BCL2L10, which could induce apoptosis and inhibit proliferation of cancer cells, might be one of the underlying mechanisms for gastric carcinogenesis.

Azacitidine↗
PubMed2006

Nucleotide change of codon 38 in the X gene of hepatitis B virus genotype C is associated with an increased risk of hepatocellular carcinoma.

BACKGROUND/AIMS: The hepatitis B virus (HBV) genotype C is associated with the development of hepatocellular carcinoma (HCC). In addition, the HBV X gene, which encodes the pleiotropic transactivator HBx, has also been associated with the development of HCC. In this study, we investigated whether nucleotide changes in the X gene of genotype C are associated with the development of HCC. METHODS/RESULTS: We sequenced the X gene in age- and sex-matched 39 HBV-infected patients with HCC and 36 HBV-infected patients without HCC. A novel nucleotide change that resulted in a proline to serine substitution at codon 38 in HBx (codon-38 change) was preferentially found in patients with HCC. Then, sera were collected from a new group of age- and sex-matched 52 patients with HCC and 51 patients without HCC. In this cohort also, the codon-38 change was associated with HCC. Multiple logistic regression analysis showed the prevalence of the codon-38 change was significantly associated with HCC in all patients (P=0.001, odds ratio: 4.89). CONCLUSION: The codon-38 change in genotype C is an independent risk factor for the development of HCC and may serve as a useful molecular marker for predicting the clinical outcomes in patients infected with HBV.

Biopsy↗
PubMed2006

Sequential gene expression changes in cancer cell lines after treatment with the demethylation agent 5-Aza-2'-deoxycytidine.

BACKGROUND: 5-Aza-2'-deoxycytidine (5-AzaC) is known well for its demethylation effect and is a promising anticancer agent. However, to the authors' knowledge, serial changes in gene expression over time after 5-AzaC treatment have not been studied to date. To clarify the categories of genes that are up-regulated or down-regulated after 5-AzaC treatment, the authors surveyed the genes that had expression levels changed by 5-AzaC treatment in 6 hepatoma cell lines (Hep3B, HLE, Huh7, HepG2, PLC/PRF/5, and Huh6). METHODS: Cell lines were grown in medium that contained 1 microM of 5-AzaC. Changes in messenger RNA levels were monitored from 24 hours up to 120 hours after 5-AzaC treatment using an in-house microarray that consisted of 4608 combinational DNAs. Using clustering analysis to identify the genes that had gradually changed expression levels and to exclude the substantial experimental noise by microarray analysis, the authors focused on 206 up-regulated genes and 248 down-regulated genes. RESULTS: According to their functional characterization, genes that were involved in the cytoskeleton and the extracellular matrix were enriched significantly in the up-regulated genes. Conversely, genes that were involved in metabolism were enriched significantly in the down-regulated genes. CONCLUSIONS: The current results demonstrated that 5-AzaC can regulate the expression of groups of genes with characteristic functions.

Azacitidine↗
PubMed2006

Serum osteopontin levels in patients with acute liver dysfunction.

OBJECTIVE: Fulminant hepatic failure (FHF) is a clinical syndrome of sudden and severe liver dysfunction accompanied by encephalopathy in a previously healthy person. In FHF, hepatocytes are severely damaged and ordinary liver regeneration is impaired. We demonstrated that the expression of osteopontin (OPN), a multifunctional cytokine, was up-regulated in mouse oval cell (a stem-cell progenitor) induction models. MATERIAL AND METHODS: Based on this finding, serum OPN levels were examined in 43 patients with FHF and in 45 patients with acute self-limited hepatitis (AH). To determine the cellular source of OPN, the expression of OPN was studied in a liver specimen derived from an FHF patient. RESULTS: The mean OPN level of patients with FHF was 2.80+/-0.48 ng/ml (log(10), +/-SD), which was significantly higher than that of the patients with AH (2.42+/-0.39 ng/ml) (p=0.003, unpaired t-test). Patients with elevated serum OPN levels had a significantly poorer prognosis than patients whose serum OPN levels were not elevated. In the FHF patient's liver, OPN protein was expressed not only in inflammatory cells but also in regenerating hepatocytes and bile ductular structures. CONCLUSIONS: Our current study indicates that serum OPN levels increased in patients with FHF and that OPN might play an important role in liver regeneration due to activation of hepatic stem cells.

Acute Disease↗
PubMed2006

Twenty-four weeks of interferon alpha-2b in combination with ribavirin for Japanese hepatitis C patients: sufficient treatment period for patients with genotype 2 but not for patients with genotype 1.

BACKGROUND: Hepatitis C virus (HCV) RNA titer and HCV genotype are two major determinants of the outcome of interferon (IFN) monotherapy. To clarify the usefulness of combination therapy with IFN and ribavirin in Japanese hepatitis C patients, we treated patients with a relatively high dose of IFN in combination with ribavirin for 24 weeks and examined the effects in relation to the viral parameters. METHODS: Two hundred and ninety-five patients were enrolled in the study. The patients received either 6 or 10 million units (MU) of interferon alpha-2b every day for 2 weeks and then three times a week for 22 weeks with a daily dose of either 600 or 800 mg of ribavirin. The treatment response and safety of this treatment were examined. RESULTS: The sustained virologic response (SVR) rates were 26.8% in genotype 1 and 76.5% in genotype 2 (P < 0.001), and 36.1% with the 6 MU group and 45.8% with the 10 MU group (P = 0.09). Multivariate analysis indicated that SVR was associated with genotype 2, HCV RNA <500 kilointernational unit/ml (kIU/ml), and HCV RNA undetectability at week 8 of treatment. CONCLUSION: Our current study showed that a 24-week course of IFN plus ribavirin combination therapy was effective with respect to virologic response in Japanese hepatitis C patients, particularly in patients with HCV genotype 2.

Adolescent↗
PubMed2006

[Hepatitis E virus infection in Japan].

Hepatitis E virus (HEV) is the major etiologic agent of enterically transmitted viral hepatitis in many developing countries. Epidemics are primarily waterborne in areas where water supplies are contaminated with HEV of human origin. There is increasing evidence, however, that HEV is also prevalent in very low numbers in non-endemic countries, including Japan. Although the source of HEV in these sporadic cases is unknown, a recently isolated swine virus is the best candidate for causing a zoonotic form of hepatitis E. The virus is serologically cross-reactive with human HEV and genetically very similar, and the human and swine strains seem to be cross-infective. Very recent evidence has also shown that swine HEV, and possibly a deer strain of HEV, may be related to avian HEV and HEV in other hosts and potential reservoirs. We examined the prevalence of anti-HEV IgM and IgG among patients serologically diagnosed with non-A, non-B, non-C acute hepatitis (n = 126) and compared with a matched control group of 76 individuals. Enzyme-linked immunosorbent assay revealed a significant difference in seroprevalence between the two groups for anti-HEV IgM (5.6% versus 0%), whereas there was no difference for anti-HEV IgG (21.4% versus 26.3%). For confirmed cases of anti-HEV IgM we also detected HEV RNA in sera by means of a sensitive polymerase chain reaction (PCR) assay. This study provides evidence of locally acquired hepatitis E in the Chiba area. Therefore, in cases of unexplained acute hepatitis, the diagnosis of hepatitis E should be considered even in the absence of foreign travel.

Animals↗
PubMed2005

Prolonged acute hepatitis A mimicking autoimmune hepatitis.

AIM: We report a case with a prolonged course of hepatitis A, with alanine aminotransferase (ALT) higher than 500 IU/L for more than 2 mo. METHODS: A middle-aged woman had an elevated IgG level of more than 2,000 mg/dL, positive anti-nuclear antibodies (ANA) and anti-smooth muscle antibodies (ASMA), but no evidence of persistent hepatitis A virus (HAV) infection. Liver biopsy findings were compatible with prolonged acute hepatitis, although acute onset of autoimmune hepatitis could not be ruled out. RESULTS: It was assumed that she developed a course of hepatitis similar to autoimmune hepatitis triggered by HAV infection. Ursodeoxycholic acid (UDCA) treatment was initiated and a favorable outcome was obtained. CONCLUSION: We describe a case of a middle-aged woman who showed a prolonged course of acute hepatitis A mimicking autoimmune hepatitis. Treatment with UDCA proved to be effective.

Acute Disease↗
PubMed2005

Effect of lamivudine in HBeAg-positive chronic hepatitis B: discordant effect on HBeAg and HBV DNA according to pretreatment ALT level.

AIM: To clarify differences in antiviral effect of the drug in patients with different ALT levels, we examined the changes in HBV markers in patients with high or low ALT levels with or without lamivudine treatment. METHODS: Thirty-seven HBeAg-positive patients were studied. Ten patients with ALT levels higher than 200 IU/L (group 1) and 8 patients with ALT below 200 IU/L (group 2) were treated orally with 100 mg/d of lamivudine. As untreated control, 9 patients with ALT above 200 IU/L (group 3) and 10 patients with ALT below 200 IU/L (group 4) were examined. ALT level, HBeAg/HBeAb status, and HBV DNA level were examined monthly for 11.9+/-0.4 mo. RESULTS: The ALT level normalized in all 10 patients of group 1, 7/8 of group 2, 4/9 of group 3, and 1/10 of group 4 within 6 mo (groups 1 vs 2, P = NS; groups 1 vs 3, P = 0.002; groups 1 vs 4, P<0.0001). HBV DNA fell below the detection limit in all 10 patients of group 1, 7/8 of group 2, 0/9 of group 3, and 0/10 of group 4 within 6 mo (groups 1 vs 2, P = NS). HBeAg became seronegative in 7/10 patients of group 1, 1/8 of group 2, 3/9 of group 3, and 0/10 of group 4 within 12 mo (groups 1 vs 2, P = 0.02; groups 1 vs 3, P = NS). CONCLUSION: Our data suggest that HBeAg-positive patients with higher ALT levels can be considered good candidates for lamivudine therapy, probably because lamivudine accelerates the natural seroconversion of HBeAg, accompanied by HBV DNA loss, in these patients.

Adult↗
PubMed2005

Hepatitis C virus core protein and hepatitis activity are associated through transactivation of interleukin-8.

BACKGROUND: We evaluated the association between variations in hepatitis C virus (HCV) core protein and hepatitis severity in patients with chronic HCV infection who achieved remission without viral eradication and had a biochemical response to interferon (IFN) therapy, to evaluate the effect of HCV core sequence in the absence of the influence of host factors. METHODS. Using serum from 10 patients with a biochemical response and 10 patients with no response, we measured serum levels of interleukin (IL)-1 beta , IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IFN- gamma , and tumor necrosis factor- alpha before and after IFN therapy. Expression vectors with the core region were transfected into Huh7 cells, and cytokine induction was evaluated by reporter assay. RESULTS: In biochemical responders, only IL-8 levels decreased after IFN therapy (P=.04). Changes in the C-terminal hydrophobic region were observed more frequently in biochemical responders. Activation of the IL-8 promoter by HCV core protein was significantly decreased in biochemical responders after IFN therapy (P=.04). When 69 C-terminal amino acids from before IFN therapy were replaced with those from after IFN therapy in 3 biochemical responders, their ability to transactivate IL-8 decreased. CONCLUSIONS: Differences in amino acids in the HCV core protein correlates with hepatitis activity through the modulation of IL-8 induction in HCV-infected patients.

Adult↗
PubMed2005

Amantadine inhibits hepatitis A virus internal ribosomal entry site-mediated translation in human hepatoma cells.

The effect of six drugs (amantadine, glycyrrhizin, ribavirin, ursodeoxycholic acid, alcohol, and IFN) on HAV RNA translation from the HAV internal ribosomal entry site (IRES) was investigated using a bicistronic reporter construct containing HAV IRES as intragenic spacer. Huh-7 cells and derivatives were transfected with in vitro transcripts, and the reporter gene activity was determined. IFN suppressed both cap-dependent and HAV IRES-dependent translation, while amantadine specifically inhibited HAV IRES-dependent translation. In contrast to IFN, by reporter assay, amantadine did not activate the interferon-stimulated response element (ISRE) or interferon gamma-activated sequence (GAS)-associated pathways. Immunoblot analysis revealed that amantadine had no effect on PKR and on IFN-regulatory factor-1 (IRF-1) expression. These findings demonstrated a novel antiviral effect of amantadine against HAV with or without HCV infection.

Amantadine↗
PubMed2005

Antiviral therapy for cirrhotic hepatitis C: association with reduced hepatocellular carcinoma development and improved survival.

BACKGROUND: Although cirrhosis is a major risk factor for development of hepatocellular carcinoma, no definitive prospective analyses have assessed the long-term efficacy of antiviral therapy in cirrhotic patients. OBJECTIVE: To elucidate the role of antiviral therapy in the suppression of liver tumors and survival over a long-term follow-up period. DESIGN: Prospective cohort study. SETTING: 25 clinical centers. PATIENTS: 345 patients with chronic hepatitis C and cirrhosis enrolled in previous trials. INTERVENTION: 271 patients received 6 to 9 million U of interferon 3 times weekly for 26 to 88 weeks; 74 received no treatment. MEASUREMENTS: Blood tests and abdominal ultrasonography were done regularly to detect hepatocellular carcinoma. RESULTS: Hepatocellular carcinoma was detected in 119 patients during a 6.8-year follow-up: 84 (31%) in the interferon-treated group and 35 (47%) in the untreated group. Cumulative incidence of hepatocellular carcinoma among interferon-treated patients was significantly lower than in untreated patients (Cox model: age-adjusted hazard ratio, 0.65 [95% CI, 0.43 to 0.97]; P = 0.03), especially sustained virologic responders. A total of 69 patients died during follow-up: 45 (17%) in the treated group and 24 (32%) in the untreated group. Interferon-treated patients had a better chance of survival than the untreated group (Cox model: age-adjusted hazard ratio, 0.54 [CI, 0.33 to 0.89]; P = 0.02). This was especially evident in sustained virologic responders. LIMITATION: This was not a randomized, controlled study. Patients enrolled in the control group had declined to receive interferon treatment even though they were eligible for treatment. CONCLUSION: Interferon therapy for cirrhotic patients with chronic hepatitis C, especially those in whom the infection had been cured, inhibited the development of hepatocellular carcinoma and improved survival.

Antiviral Agents↗
PubMed2005

Identification and investigation of methylated genes in hepatoma.

Gene silencing due to aberrant DNA methylation plays an important role in carcinogenesis. Previous microarray analysis demonstrated that 14 genes, including hepatocyte growth factor activator inhibitor 2/placental bikunin (HAI2/PB) gene, showed particularly high inductions after 5-aza-2'deoxycytidine (5Aza-dC) treatment in multiple hepatoma cell lines. In the present study, we studied all of these genes except for the HAI2/PB gene and examined DNA methylation status and levels of acetylated histones using bisulphite genomic sequencing and the chromatin immunoprecipitation (ChIP) assay, respectively. Aberrant methylation in primary hepatoma tissues was also examined using methylation-specific polymerase chain reaction (MSP). Genes for E-cadherin, collagen type I alpha 2 (COL1A2), insulin-like growth factor binding protein 2 (IGFBP2), connective tissue growth factor (CTGF) and fibronectin 1 exhibited aberrant methylation in several hepatoma cell lines. The ChIP assay showed that DNA methylation and deacetylation of histones generally coexist except for fibronectin 1. In further studies of 24 primary hepatoma tissues, methylation signals for COL1A2, IGFBP2, CTGF and fibronectin 1 were detected in 13, 18, 4 and 10 patients, respectively. In conclusion, aberrant methylation of COL1A2, IGFBP2, CTGF and fibronectin 1 genes were detected in hepatoma cell lines. We also demonstrated that the methylation of 5'CpG islands and histone deacetylation generally coexisted in the regulation of gene expression except for fibronectin 1. The results of MSP in hepatoma tissues suggested that some of these genes might be involved in the development or progression of hepatoma.

Adult↗
PubMed2005

Lamivudine treatment in a patient with hepatitis B virus reactivation after allogenic peripheral bone marrow transplantation.

We report the case of a 52-year-old woman with hepatitis B virus (HBV) reactivation during treatment for chronic graft vs. host disease (GVHD) after peripheral bone marrow transplantation (PBSCT) to treat chronic myelocytic leukemia. She was given cyclosporine and prednisolone orally to treat chronic GVHD after PBSCT. Liver dysfunction first developed 25 months after transplantation with the appearance of hepatitis B s antigen (HBsAg), hepatitis B e antigen (HBeAg), and elevation of HBV-DNA up to 4.5 log copies/ml. Retrospective examination of her serum before PBSCT proved negative for HBsAg and HBeAg, and positive for anti-HBsAg, anti-HBeAg, anti-hepatitis B core antigen, and HBV-DNA (2.7 log copies/ml), showing that she was in a state of occult HBV infection. Nucleotide sequences of the HBV genome obtained from her serum showed no core promoter mutations at nt 1762 and 1764 and no pre-core mutation at nt 1896. Polymerase chain reaction-restriction fragment length polymorphism showed that she was infected with HBV genotype B. The administration of lamivudine, a nucleoside analog, improved her liver function and reduced HBV-DNA replication. We conclude that antiviral agents, such as lamivudine, are effective for treating hepatitis B reactivation during immunosuppressive treatment, such as for GVHD. The administration of a nucleoside analog before transplantation should also be considered in the light of HBV genotypes and mutations, even if HBsAg was negative and the viral load was low before transplantation.

Antigens, Viral↗
PubMed2005

Enhanced sensitivity of human hepatoma cells to 5-fluorouracil by small interfering RNA targeting Bcl-2.

This study was designed to reveal whether the apoptosis induced in human hepatocellular carcinoma (HCC) cell lines by 5-fluorouracil (5-FU) could be enhanced by transfecting Bcl-2 small interfering RNA (siRNA). Bcl-2 siRNA and control siRNA were transfected into cells following treatment with or without 5-FU. Suppression of Bcl-2 expression was confirmed by Western blotting; cell viability was evaluated by MTS assay, and the occurrence of apoptosis in cells was evaluated by apoptosis assay. Expression of Bcl-2 protein after transfection of 20 nM Bcl-2 siRNA was significantly lower than that of control. Incubation of all cell lines with Bcl-2 siRNA reduced cell viability 96 h after 5-FU treatment compared with all other controls: Huh-7 (P < 0.01), Huh-7 with hepatitis C replicon (P < 0.01), HepG2 (P < 0.01), HLE (P < 0.05). Moreover, the proportion of apoptosis in control siRNA, Bcl-2 siRNA, control siRNA prior to 5-FU treatment, and Bcl-2 siRNA prior to 5-FU treatment groups were (4.6 +/- 2.3)%, (7.5 +/- 0.5)%, (6.0 +/- 2.1)%, and (19.5 +/- 0.86)%, respectively. The Bcl-2 siRNA prior to 5-FU treatment group showed the strongest effect of inducing apoptosis. In conclusion, the combination Bcl-2 siRNA and 5-FU might represent a new therapeutic option for HCC.

Antimetabolites, Antineoplastic↗
PubMed2005

Lower incidence of hepatic failure than hepatocellular carcinoma in Japanese patients with chronic hepatitis C.

BACKGROUND: Previous studies have shown that the development of hepatic failure was found more frequently than that of hepatocellular carcinoma (HCC) in patients with chronic hepatitis C in the United States and European countries. We investigated the status in Japan in a retrospective cohort study. METHODS: The incidences of HCC and hepatic failure were accessed in 459 patients with biopsy-proven C-viral chronic liver disease with a mean follow-up period of 8.9+/-3.2 years and the cause of death was also analyzed in the cohort. RESULTS: HCC developed in 63 patients, 46 of 355 interferon (IFN)-treated and 17 of 104 untreated patients. In contrast, the development of hepatic failure was found in 18 patients, 12 of 355 IFN-treated and six of 104 untreated patients. HCC developed in four of 116 with sustained virological response (SVR), and hepatic failure developed in one of them. Thirty-two of 63 patients developing HCC and eight of 18 patients developing hepatic failure died. CONCLUSIONS: Development of hepatic failure was less frequent than that of HCC in Japan. It is important for a favorable prognosis of patients with C viral chronic liver disease to achieve a higher SVR and thus inhibit the development of HCC in Japan.

Antiviral Agents↗