13 results on '"Yasuhiro Itsui"'
Search Results
2. Oral health status and its association with nutritional support in malnourished patients hospitalised in acute care
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Yuji Sato, Yukue Shimizu, Kanako Yoshimi, Kazuharu Nakagawa, Yasuhiro Itsui, Shunsuke Minakuchi, Keiko Saito, Rena Hidaka, Junichi Furuya, Ayako Nakane, Ayano Akatsuka, Hiroyuki Suzuki, and Haruka Tohara
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Pediatrics ,medicine.medical_specialty ,Psychological intervention ,Nutritional Status ,Oral Health ,Oral health ,Oral hygiene ,Enteral Nutrition ,Acute care ,medicine ,Humans ,General Dentistry ,Aged ,Aged, 80 and over ,Nutritional Support ,business.industry ,Malnutrition ,medicine.disease ,Dysphagia ,Active participation ,Cross-Sectional Studies ,Nutrition Assessment ,Female ,Geriatrics and Gerontology ,medicine.symptom ,business ,Body mass index - Abstract
Objectives This cross-sectional study aimed to examine the oral health of malnourished acute-care hospital inpatients, who were the subjects of a nutritional support team (NST). We also aimed to elucidate the systemic and nutritional factors associated with the oral health of those patients. Background Interventions by NST are essential for inpatient nutrition management and require the active participation of dental professionals. However, information is limited regarding the state of oral health among acute-stage malnourished inpatients. Materials and methods We enrolled 255 hospitalised patients (101 women, mean age: 69.7 ± 14.4 years) who were referred to an NST for nutrition management between April 2016 and July 2019. The main outcome was the Oral Health Assessment Tool (OHAT) scores. Moreover, we assessed participants' demographic characteristics, nutritional status, number of natural and functional teeth, posterior occlusal support, denture use, Dysphagia Severity Scale, whether oral health management was needed, and the methods of nutrition intake. Results Several participants presented with a deteriorated oral health. Consequently, oral health management was often regarded necessary in these patients. Approximately half were fed by parenteral or tube feeding. Multiple regression analysis revealed the OHAT score has a positive association with age (P = .008), and a negative association with body mass index (P = .009) and the method of nutrition intake (P = .028). Conclusion Malnourished inpatients at an acute care hospital who were subject to an NST had a deteriorated oral health status. Additionally, poor oral health was associated with poor nutritional status and nutrition intake methods.
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- 2021
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3. Time course alterations of virus sequences and immunoglobulin titers in a chronic hepatitis E patient
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Fukiko Kawai-Kitahata, Yasuhiro Itsui, Mina Nakagawa, Sayuri Nitta, Kazuaki Takahashi, Yasuhiro Asahina, Masato Miyoshi, Seishin Azuma, Jun Tsuchiya, Mamoru Watanabe, Miyako Murakawa, Sei Kakinuma, and Ayako Sato
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viruses ,medicine.disease_cause ,Immunoglobulin G ,Virus ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Hepatitis E virus ,medicine ,Hepatology ,biology ,business.industry ,Ribavirin ,virus diseases ,Hepatitis E ,medicine.disease ,Virology ,digestive system diseases ,Chronic infection ,Infectious Diseases ,chemistry ,Immunoglobulin M ,030220 oncology & carcinogenesis ,biology.protein ,030211 gastroenterology & hepatology ,Antibody ,business - Abstract
Aim Hepatitis E virus (HEV) can cause chronic infection in immunocompromised hosts. However, the dynamics of HEV during persistent infection is not well understood. To elucidate time course alterations in virus sequences and anti-HEV antibodies during persistent infection, we analyzed the HEV sequences and titers of anti-HEV antibodies from a chronic hepatitis E patient. Methods Serum samples were obtained from a chronic hepatitis E patient under corticosteroid therapy for neurological disease. The titers of anti-HEV antibodies (immunoglobulin A, immunoglobulin M, and immunoglobulin G) in serum samples were detected by enzyme immunoassay. The full or near-full nucleotide sequences of HEV isolated from consecutive serum samples were identified and compared. Phylogenetic analysis was also performed. Results Alterations of anti-HEV antibodies from a chronic hepatitis E patient were different from those previously reported in acute hepatitis E patients. The virus sequence was unchanged in the period without treatment, but nucleotide mutations were observed after ribavirin treatment was started. In addition, the sequence of this strain had extremely high identity to that isolated from swine liver in Japan. Conclusions Virus mutations in HEV emerged after ribavirin treatment was started. Sequence analysis may useful for deciding the treatment strategy for chronic hepatitis E patients who did not eliminate the virus with 3 months of RBV treatment and inferring the origin of the infection. This report provides insights into the chronicity of hepatitis E, and the impact of persistent infection and ribavirin treatment on the emergence of virus mutations.
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- 2020
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4. ITPA gene variation and ribavirin-induced anemia in patients with genotype 2 chronic hepatitis C treated with sofosbuvir plus ribavirin
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Mina Nakagawa, Toshihiko Nouchi, Shun Kaneko, Hiroko Nagata, Mamoru Watanabe, Sei Kakinuma, Sayuri Nitta, Fukiko Kawai-Kitahata, Miyako Murakawa, Yoshimichi Chuganji, Tooru Asano, Yu Asano, Masato Miyoshi, Satoshi Otani, Yasuhiro Itsui, Ayako Sato, Tomoyuki Tsunoda, Seishin Azuma, Yohei Furumoto, Shuji Tohda, and Yasuhiro Asahina
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0301 basic medicine ,Hemolytic anemia ,medicine.medical_specialty ,Sofosbuvir ,Combination therapy ,Anemia ,Hepatitis C virus ,medicine.disease_cause ,Gastroenterology ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Internal medicine ,medicine ,Hepatology ,business.industry ,Ribavirin ,medicine.disease ,030104 developmental biology ,Infectious Diseases ,chemistry ,Immunology ,030211 gastroenterology & hepatology ,ITPA ,business ,Pharmacogenetics ,medicine.drug - Abstract
Aim Sofosbuvir (SOF) and ribavirin (RBV) combination therapy produces a sustained response in many patients with genotype 2 chronic hepatitis C. However, RBV-induced anemia is a troublesome side effect that may limit this treatment. Genetic variation leading to inosine triphosphatase (ITPA) deficiency is known to protect against RBV-induced hemolytic anemia. This study aimed to evaluate the relationships between the efficacy and safety of SOF/RBV treatment and ITPA gene variants. Methods Ninety patients with genotype 2 chronic hepatitis C treated with SOF/RBV were studied. The relationships among genetic polymorphisms of ITPA and the decline in hemoglobin (Hb) levels from baseline, RBV dose reduction, and sustained virological response (SVR) rates were analyzed. Results Overall SVR at 12 weeks was 94.4% (85/90). Patients with the ITPA CA/AA genotypes had a lower degree of anemia throughout the therapy than those with the ITPA CC genotype. The percentage of patients requiring RBV dose reduction was significantly lower for those with the ITPA CA/AA variation, a difference even more apparent when the pretreatment Hb level was
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- 2017
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5. Hepatic IFNL4 expression is associated with non-response to interferon-based therapy through the regulation of basal interferon-stimulated gene expression in chronic hepatitis C patients
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Mina Nakagawa, Hiroko Nagata, Yu Asano, Satoshi Otani, Sei Kakinuma, Sayuri Nitta, Mamoru Watanabe, Shuji Tohda, Seishin Azuma, Yasuhito Tanaka, Sayuki Iijima, Kaoru Tsuchiya, Yasuhiro Asahina, Fukiko Kawai-Kitahata, Shun Kaneko, Yasuhiro Itsui, Miyako Murakawa, Namiki Izumi, Tomoyuki Tsunoda, and Masato Miyoshi
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Adult ,Male ,Myxovirus Resistance Proteins ,0301 basic medicine ,Genotype ,Hepatitis C virus ,Hepacivirus ,medicine.disease_cause ,Polymorphism, Single Nucleotide ,03 medical and health sciences ,chemistry.chemical_compound ,Suppressor of Cytokine Signaling 1 Protein ,0302 clinical medicine ,Interferon ,Virology ,Drug Resistance, Viral ,Ribavirin ,Gene expression ,Humans ,Medicine ,RNA, Messenger ,SOCS3 ,Ubiquitins ,Gene ,Aged ,business.industry ,Interleukins ,Interferon-stimulated gene ,Interferon-alpha ,virus diseases ,Hepatitis C, Chronic ,Middle Aged ,ISG15 ,030104 developmental biology ,Infectious Diseases ,Gene Expression Regulation ,Liver ,chemistry ,Immunology ,Cytokines ,Female ,030211 gastroenterology & hepatology ,Interferons ,business ,medicine.drug - Abstract
Single nucleotide polymorphisms (SNPs) within or near interferon lambda 4 (IFNL4) gene located upstream of IFNL3 are associated with response to anti-HCV therapy both in interferon (IFN)-based and IFN-free regimens. IFNL4 encodes IFNλ4, a newly discovered type III IFN, and its expression is controlled by rs368234815-TT/ΔG, which is in strong linkage disequilibrium (LD) with other tag SNPs within or near IFNL4 such as rs12979860 and rs8099917. Intrahepatic expression levels of IFN-stimulated genes (ISGs) affect the responsiveness to IFNα and are also associated with IFNL4 genotype. However, IFNL4 expressions and its role in intrinsic antiviral innate immunity remain unclear. This study evaluated the effect of IFNL4 on intrahepatic ISG expression and investigated its relationship with treatment outcomes in liver samples obtained from 49 chronic hepatitis C patients treated with pegylated (PEG)-IFN/ribavirin therapy. IFNL4 mRNA was detected in 11 of 22 patients with IFNL4-unfavorable SNPs but not in patients with favorable genotypes. IFNL4 expression was associated with non-response to PEG-IFN/ribavirin therapy. Intrahepatic expression of antiviral ISGs (ISG15 and MX1) was significantly higher in IFNL4-unfavorable patients with detectable IFNL4 mRNA than in patients with undetectable IFNL4 mRNA, whereas the expression of suppressive ISGs (RNF125, SOCS1, SOCS3, and RNF11) was lower in patients with detectable IFNL4 mRNA. In summary, intrahepatic expression of IFNL4 was associated with increased antiviral ISG expression and decreased suppressive ISG expression at baseline, resulting in poor responsiveness to IFNα-based therapy in HCV infection.
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- 2017
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6. Bone morphogenetic protein-4 modulates proliferation and terminal differentiation of fetal hepatic stem/progenitor cells
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Shun Kaneko, Ayako Sato, Mamoru Watanabe, Yasuhiro Asahina, Yasuhiro Itsui, Sei Kakinuma, Hiroko Nagata, Fumio Goto, Sayuri Nitta, Yu Asano, Satoshi Otani, Tomoyuki Tsunoda, Seishin Azuma, Masato Miyoshi, Mina Nakagawa, Fukiko Kawai-Kitahata, and Miyako Murakawa
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0301 basic medicine ,MAPK/ERK pathway ,Hepatology ,p38 mitogen-activated protein kinases ,Biology ,Cell biology ,WNT5A ,03 medical and health sciences ,030104 developmental biology ,Infectious Diseases ,Downregulation and upregulation ,Bone morphogenetic protein 4 ,embryonic structures ,Progenitor cell ,Stem cell ,Protein kinase B - Abstract
Aim Fetal hepatic stem/progenitor cells, called hepatoblasts, play central roles in liver organogenesis; however, molecular mechanisms regulating proliferation and terminal differentiation of such cells have not been completely elucidated. Bone morphogenetic protein-4 (BMP-4) is essential for the development of stem cells in various tissues, but its function in regulating the phenotype of hepatoblasts after mid-gestational fetal stage remains unclear. The aim of this study is to clarify a functional role for BMP-4 in proliferation and terminal differentiation of murine hepatoblasts in mid-gestational fetal livers. Methods A functional role for BMP-4 in proliferation and terminal differentiation of murine hepatoblasts was validated by assay of colony formation, biliary luminal formation, and hepatic maturation using primary hepatoblasts in vitro. Molecular mechanisms regulating such effects of BMP-4 on primary hepatoblasts were also analyzed. Results BMP-4 stimulation upregulated phosphorylation of Smad1/5 in hepatoblasts. BMP-4 significantly suppressed colony formation of primary hepatoblasts in a dose-dependent manner. BMP-4 significantly suppressed cholangiocytic luminal formation of hepatoblasts, and promoted hepatic maturation of primary hepatoblasts. BMP-4 stimulation regulated the activation of several mitogen-activated protein kinases (MAPK), such as extracellular signal-regulated kinase, Akt, p38 MAPK, and calcium/calmodulin-dependent protein kinase IIα in primary hepatoblasts. Moreover, Wnt5a, a molecule regulating cholangiocytic luminal formation, and BMP-4 coordinately suppressed proliferation and cholangiocytic luminal formation of hepatoblasts. Conclusion This study demonstrates that BMP-4–mediated signaling controls proliferation and terminal differentiation of fetal hepatic stem/progenitor cells. This article is protected by copyright. All rights reserved.
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- 2016
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7. Efficacy of additional radiofrequency ablation after transcatheter arterial chemoembolization for intermediate hepatocellular carcinoma
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Megumi Tasaka-Fujita, Yasuhiro Itsui, Yasuhiro Asahina, Takako Watanabe, Miyako Murakawa, Sei Kakinuma, Mina Nakagawa, Fumio Goto, Fukiko Kawai-Kitahata, Shun Kaneko, Mamoru Watanabe, Miki Taniguchi, Hiroko Nagata, Satoshi Ootani, Yuki Nishimura-Sakurai, and Seishin Azuma
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medicine.medical_specialty ,Hepatology ,business.industry ,Bilirubin ,Radiofrequency ablation ,Retrospective cohort study ,Small sample ,Cumulative survival ,medicine.disease ,Gastroenterology ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Infectious Diseases ,chemistry ,law ,030220 oncology & carcinogenesis ,Internal medicine ,Hepatocellular carcinoma ,Overall survival ,Medicine ,030211 gastroenterology & hepatology ,business ,Transcatheter arterial chemoembolization - Abstract
Aim For intermediate hepatocellular carcinoma (HCC), transcatheter arterial chemoembolization (TACE) therapy is recommended in the guidelines as a monotherapy, although TACE is a non-curative therapy. The aims of the present study were to evaluate the efficacy of adding radiofrequency ablation (RFA) to TACE in patients with intermediate HCC, and to identify the factors that were associated with favorable survival in these patients. Methods Fifty-nine patients with intermediate HCC were enrolled in this retrospective study. Thirty-nine patients were treated with TACE alone and 20 patients were treated with additional RFA after TACE. Results The recurrence-free survival rates at 0.5, 1 and 2 years for the additional RFA group were 32%, 19% and 13%, respectively, and these were significantly higher than those of the TACE group (8%, 3% and 0%, respectively; log–rank test, P = 0.001). The cumulative survival rates of the additional RFA group were significantly higher than those of the TACE group (log–rank test, P = 0.002), although this significant difference was not found in the subgroup of treatment naive patients because of small sample size. Multivariate analysis indicated male sex, lower total bilirubin, lower α-fetoprotein, lower des-γ-carboxyprothrombin, newly recurrent HCC nodules within the last 12 months and additional RFA as independent factors that were significantly associated with favorable overall survival. Conclusion Additional RFA of nodules insufficiently treated by TACE is effective therapy for obtaining favorable disease-free survival in patients with intermediate HCC, and leads to better overall survival particularly in recurrent patients.
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- 2015
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8. Impaired induction of interleukin 28B and expression of interferon λ 4 associated with nonresponse to interferon-based therapy in chronic hepatitis C
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Takako Watanabe, Mina Nakagawa, Satoshi Otani, Mamoru Watanabe, Fumio Goto, Miki Taniguchi, Fukiko Kawai-Kitahata, Sayuri Nitta, Naoya Sakamoto, Yuki Nishimura-Sakurai, Sei Kakinuma, Yasuhiro Asahina, Akiko Kusano-Kitazume, Miyako Murakawa, Yasuhiro Itsui, and Seishin Azuma
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NS3 ,Hepatology ,business.industry ,Hepatitis C virus ,Gastroenterology ,medicine.disease_cause ,Peripheral blood mononuclear cell ,Basal (phylogenetics) ,Interleukin 28B ,Interferon ,Pegylated interferon ,Genotype ,Immunology ,Medicine ,business ,medicine.drug - Abstract
Background and Aim Interferon (IFN) λ plays an important role in innate immunity to protect against hepatitis C viral (HCV) infection. Single nucleotide polymorphisms (SNPs) near IL28B (IFNλ3) are strongly associated with treatment response to IFNα therapy in chronic hepatitis C (CHC) patients. Recently, IFNλ4 related to IL28B-unfavorable allele was discovered. However, the impact of IFNλs on CHC is unknown. We aimed to investigate the mechanism underlying responsiveness to IFN-based therapy in CHC associated with SNPs near IL28B. Methods We evaluated the basal mRNA levels and ex-vivo induction of IFNλ expression including IFNλ4 in peripheral blood mononuclear cells (PBMCs) from 50 CHC patients treated with pegylated-IFNα/RBV. Furthermore, we investigated the effect of IFNλ4 on induction of IL28B in vitro. Results When PBMCs were stimulated with IFNα and polyinosinic–polycytidylic acid, IL28B induction was significantly lower in patients with IL28B-unfavorable genotype (rs12979860 CT/TT) than those with IL28B-favorable genotype (rs12979860 CC; P = 0.049). IL28B induction was lower in nonresponders than in relapsers (P = 0.04), and it was also lower in nonsustained virological responder patients for triple therapy including NS3 protease inhibitors. IFNλ4 mRNA was detected in 12 of 26 patients with IL28B-unfavorable SNP, and IFNλ4 expression was associated with lower IL28B induction in patients with IL28B-unfavorable genotype (P = 0.04) and nonresponse to IFNα therapy (P = 0.003). Overexpression of IFNλ4 suppressed IL28B induction and promoter activation. Conclusions Impaired induction of IL28B, related to IFNλ4 expression in PBMCs of IL28B-unfavorable patients, is associated with nonresponse to IFNα-based therapy for hepatitis C viral infection.
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- 2015
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9. Association of IL28B variants with response to pegylated-interferon alpha plus ribavirin combination therapy reveals intersubgenotypic differences between genotypes 2a and 2b
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Mamoru Watanabe, Mayumi Ueyama, Masashi Mizokami, Eiji Tanaka, Yasuhito Tanaka, Katsushi Tokunaga, Akihiro Tamori, Masayuki Kurosaki, Mina Nakagawa, Nao Nishida, Yoichi Hiasa, Yasuhiro Itsui, Seishin Azuma, Yuko Sekine-Osajima, Shuhei Hige, Sei Kakinuma, Naoya Sakamoto, Nishimura-Sakurai Yuki, Namiki Izumi, and Yoshito Itoh
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Adult ,Male ,Genotype ,Combination therapy ,Alpha interferon ,Interferon alpha-2 ,Biology ,Antiviral Agents ,Polyethylene Glycols ,Leukocyte Count ,chemistry.chemical_compound ,Gene Frequency ,Pegylated interferon ,Virology ,Ribavirin ,medicine ,Humans ,Allele frequency ,Aged ,Polymorphism, Genetic ,Interleukins ,Interferon-alpha ,Hepatitis C ,Hepatitis C, Chronic ,Middle Aged ,medicine.disease ,Recombinant Proteins ,Treatment Outcome ,Infectious Diseases ,Interleukin 28B ,chemistry ,Immunology ,Female ,Interferons ,medicine.drug - Abstract
Genetic polymorphisms of the interleukin 28B (IL28B) locus are associated closely with outcomes of pegylated-interferon (PEG-IFN) plus ribavirin (RBV) combination therapy. The aim of this study was to investigate the relationship between IL28B polymorphism and responses to therapy in patients infected with genotype 2. One hundred twenty-nine chronic hepatitis C patients infected with genotype 2, 77 patients with genotype 2a and 52 patients with genotype 2b, were analyzed. Clinical and laboratory parameters, including genetic variation near the IL28B gene (rs8099917), were assessed. Drug adherence was monitored in each patient. Univariate and multivariate statistical analyses of these parameters and clinical responses were carried out. Univariate analyses showed that a sustained virological response was correlated significantly with IL28B polymorphism, as well as age, white blood cell and neutrophil counts, adherence to RBV, and rapid virological response. Subgroup analysis revealed that patients infected with genotype 2b achieved significantly lower rapid virological response rates than those with genotype 2a. Patients with the IL28B-major allele showed higher virus clearance rates at each time point than those with the IL28B-minor allele, and the differences were more profound in patients infected with genotype 2b than those with genotype 2a. Furthermore, both rapid and sustained virological responses were associated significantly with IL28B alleles in patients with genotype 2b. IL28B polymorphism was predictive of PEG-IFN plus RBV combination treatment outcomes in patients infected with genotype 2 and, especially, with genotype 2b. In conclusion, IL-28B polymorphism affects responses to PEG-IFN-based treatment in difficult-to-treat HCV patients.
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- 2011
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10. Studies on virus kinetics using infectious fluorescence-tagged hepatitis C virus cell culture
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Takanobu Kato, Yasuhiro Itsui, Sei Kakinuma, Mamoru Watanabe, Yuki Nishimura-Sakurai, Mina Nakagawa, Seishin Azuma, Tetsuya Nakamura, Takaji Wakita, Naoya Sakamoto, Machi Yamamoto, and Kiichiro Tsuchiya
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Hepatology ,Hepatitis C virus ,Viral transformation ,Biology ,medicine.disease_cause ,Virology ,Molecular biology ,Virus ,NS2-3 protease ,Infectious Diseases ,Interferon ,Cell culture ,medicine ,Protease inhibitor (pharmacology) ,NS5A ,medicine.drug - Abstract
Aim: Studies of the complete hepatitis C virus (HCV) life cycle have become possible with the development of a HCV-JFH1 cell culture system. Methods: In this study, we constructed two fluorescence protein-tagged recombinant JFH1 virus clones, JFH1-EYFP and JFH1-AsRed, as well as two corresponding clones with adaptive mutations, JFH1-EYFP mutant and JFH1-AsRed mutant, that and were as effective as JFH1 in producing infectious virus particles, and investigated their viral infection life cycles. Results: After infection of the fluorescence-tagged mutant viruses, infected cells increased exponentially. In cells, EYFP or AsRed and NS5A were expressed as a fusion protein and co-localized in core proteins. The rate of the cell–cell spread was dependent on the cell densities with a maximum of 102.5/day. Treatment of cells with interferon or a protease inhibitor suppressed expansion of virus-positive cells. Conclusion: Taken together, these results indicate that fluorescence-tagged HCV is a useful tool to study virus infection life cycles and to assist in the search for novel antiviral compounds.
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- 2011
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11. Two flavonoids extracts fromGlycyrrhizae radixinhibitin vitrohepatitis C virus replication
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Nobuyuki Enomoto, Mina Nakagawa, Yuki Nishimura-Sakurai, Yuko Sekine-Osajima, Yasuhiro Itsui, Machi Yamamoto, Kiichiro Tsuchiya, Megumi Tasaka, Takanori Kanai, Mamoru Watanabe, Shinya Maekawa, Goki Suda, Kako Mishima, Cheng Hsin Chen, Yuko Onuki, and Naoya Sakamoto
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Hepatology ,Cell growth ,Biology ,Pharmacology ,In vitro ,chemistry.chemical_compound ,Infectious Diseases ,Viral replication ,chemistry ,In vivo ,Luciferase ,Replicon ,Medicinal plants ,Isoliquiritigenin - Abstract
Aim: Traditional herbal medicines have been used for several thousand years in China and other Asian countries. In this study we screened herbal drugs and their purified compounds, using the Feo replicon system, to determine their effects on in vitro HCV replication. Methods: We screened herbal drugs and their purified extracts for the activities to suppress hepatitis C virus (HCV) replication using an HCV replicon system that expressed chimeric firefly luciferase reporter and neomycin phosphotransferase (Feo) genes. We tested extracts and 13 purified compounds from the following herbs: Glycyrrhizae radix; Rehmanniae radix; Paeoniae radix; Artemisiae capillari spica; and Rhei rhizoma. Results: The HCV replication was significantly and dose-dependently suppressed by two purified compounds, isoliquiritigenin and glycycoumarin, which were from Glycyrrhizae radix. Dose-effect analyses showed that 50% effective concentrations were 6.2 ± 1.0 µg/mL and 15.5 ± 0.8 µg/mL for isoliquiritigenin and glycycoumarin, respectively. The MTS assay did not show any effect on cell growth and viability at these effective concentrations, indicating that the effects of the two compounds were specific to HCV replication. These two compounds did not affect the HCV IRES-dependent translation nor did they show synergistic action with interferon-alpha. Conclusion: Two purified herbal extracts, isoliquiritigenin and glycycoumarin, specifically suppressed in vitro HCV replication. Further elucidation of their mechanisms of action and evaluation of in vivo effects and safety might constitute a new anti-HCV therapeutics.
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- 2009
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12. Expressional screening of interferon-stimulated genes for antiviral activity against hepatitis C virus replication
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Nobuyuki Enomoto, Shinya Maekawa, Mamoru Watanabe, Masayuki Kurosaki, Yoshie Takeda, Yasuhiro Itsui, Naoya Sakamoto, Sei Kakinuma, Yuko Sekine, Yoko Tanabe, Tomoyuki Koyama, Nobuhiko Kanazawa, and Mina Nakagawa
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viruses ,Hepatitis C virus ,Down-Regulation ,Hepacivirus ,Biology ,Response Elements ,Virus Replication ,medicine.disease_cause ,Cell Line ,Mitochondrial Proteins ,Small hairpin RNA ,GTP-Binding Proteins ,Interferon ,Cell Line, Tumor ,Virology ,medicine ,Humans ,Replicon ,Gene ,Gene Library ,Hepatology ,Gene Expression Profiling ,Interferon-stimulated gene ,Interferon-alpha ,Proteins ,virus diseases ,biochemical phenomena, metabolism, and nutrition ,Protein kinase R ,Molecular biology ,digestive system diseases ,Infectious Diseases ,Gene Expression Regulation ,Liver ,Viral replication ,Interferon Regulatory Factors ,Signal Transduction ,medicine.drug - Abstract
Type-I interferons (IFNs) and the interferon-stimulated genes (ISGs) play a major role in antivirus responses against hepatitis C virus (HCV) infection. In this study, we studied expression profiles of ISGs in cells supporting subgenomic HCV replication (Huh7/Rep), and screened their activities to suppress HCV replication. Real-time PCR analyses showed that the expression levels of 23 ISGs were significantly lower in Huh7/Rep than naive Huh7 cells due to transcriptional suppression of the interferon-stimulated response element (ISRE). Furthermore, the expression level of ISGs was also decreased in the cured Huh7 cells in which replicon had been eliminated (cHuh7), indicating adaptation of the cells to support HCV replication by downregulating ISGs. On the other hand, expression of HCV replicon was significantly suppressed by overexpression of several ISGs including PKR, MxA, IRF-9, GBP-1, IFI-6-16, IFI-27, 25OAS and IRF-1. Knock down of GBP-1, IFI-6-16 and IFI-27 by short hairpin RNA resulted in increase of HCV replication. Thus, we conclude that downregulation of ISG expression is required in the host cells supporting HCV replication and that several ISGs directly suppress HCV replication. The search for ISGs that regulate HCV replication may help to elucidate the cellular antiviral defence mechanisms against HCV infection.
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- 2006
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13. Site-specific mutation of the interferon sensitivity-determining region (ISDR) modulates hepatitis C virus replication
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T. Kohashi, Hideki Watanabe, Naoya Sakamoto, Mina Nakagawa, Mamoru Watanabe, Nobuhiko Kanazawa, Masayuki Kurosaki, Sei Kakinuma, Nobuyuki Enomoto, Shinya Maekawa, Tsuyoshi Yamashiro, Yasuhiro Itsui, Tomoyuki Koyama, Cheng-Hsin Chen, and Yoko Tanabe
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viruses ,Hepatitis C virus ,Hepacivirus ,DNA Mutational Analysis ,Molecular Sequence Data ,Viral Nonstructural Proteins ,Virus Replication ,medicine.disease_cause ,Interferon ,Cell Line, Tumor ,Virology ,medicine ,Humans ,Amino Acid Sequence ,Replicon ,NS5A ,Gene ,Genetics ,Hepatology ,biology ,biology.organism_classification ,Protein Structure, Tertiary ,Infectious Diseases ,Amino Acid Substitution ,Viral replication ,Mutation ,Mutagenesis, Site-Directed ,Interferons ,Viral load ,medicine.drug - Abstract
The number of amino acid substitutions in the interferon sensitivity-determining region (ISDR) in the nonstructural 5A (NS5A) gene of hepatitis C virus (HCV) is closely associated with the interferon (IFN) response and viral load. Several HCV replicon-based studies have reported that ISDR sequences had an influence on viral replication in vitro. However, it is unclear as to how different ISDR sequences affect HCV replication. Various clinically observed ISDR sequences were introduced into HCV replicons and their contribution to viral replication was investigated using a colony formation assay and/or a transient replication assay. A mapping study of the ISDR was performed to identify the amino acid positions that critically affect replication. While no colonies were formed in the colony formation assay using HCV replicons with few mutations (0, 1 and 3) in the ISDR, numerous colonies (>200) appeared when using constructs with six mutations. Introduction of various distinct ISDR sequences with multiple mutations resulted in replication enhancement in transient assays. A mapping study identified several specific sites in the ISDR that critically affected replication, including codon 2209 which, in patients, was closely associated with a strong response to IFN. ISDR sequences associated with a clinical IFN response and viral load modulated the replication of HCV replicons, suggesting the importance of the ISDR sequence in HCV infection.
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- 2006
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