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Dive into the research topics where Yoshimasa Hashimoto is active.

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Featured researches published by Yoshimasa Hashimoto.


Journal of Medical Virology | 2010

Clinical and virological effects of long-term (over 5 years) lamivudine therapy

Yoshimasa Hashimoto; Fumitaka Suzuki; Miharu Hirakawa; Yusuke Kawamura; Hiromi Yatsuji; Hitomi Sezaki; Tetuya Hosaka; Norio Akuta; Masahiro Kobayashi; Satoshi Saito; Yoshiyuki Suzuki; Mariko Kobayashi; Yasuji Arase; Kenji Ikeda

Ideally, long‐term lamivudine therapy should not induce tyrosine–methionine–aspartate–aspartate (YMDD) mutants (reverse transcription [rt]; rt M204I/V) in patients with chronic hepatitis B. There is little or no information on the clinical features of patients who do not develop such mutants. We analyzed 368 patients who received lamivudine therapy for more than 6 months between 1995 and 2003. Among them, 98 patients were negative for YMDD mutants during 5‐year lamivudine therapy. Multivariate analysis identified hepatitis B e antigen (HBeAg) negativity, lack of cirrhosis, and high gamma glutamyltranspeptidase (GGTP) level as independent factors associated with lack of emergence of YMDD mutants during 5‐year treatment. In these 98 patients, 21 patients developed YMDD mutants in the 5‐year posttreatment follow‐up. Old age was identified as the only factor associated with the emergence of YMDD mutants during that period. For all patients, 53 showed no elevation of alanine aminotransferase (ALT) or viral load after emergence of YMDD mutants during 5 years. Short latency to emergence of YMDD mutants, mixed (tyrosine–isoleucine–aspartate–aspartate (YIDD) [rtM204I] + tyrosine–valine–aspartate–aspartate (YVDD) [rtM204V]) type, and low ALT level were identified as independent factors associated with elevation ALT or viral load. HBeAg negativity, lack of cirrhosis, and high GGTP level were associated with lack of emergence of YMDD mutants during 5‐year period. Young age protected against emergence of YMDD mutants over the 5‐year period. Moreover, after the emergence of YMDD mutants, short latency to the emergence of YMDD mutant, mixed type mutants, and low baseline ALT level were associated with elevation of ALT or viral load. J. Med. Virol. 82:684–691, 2010.


Hepatology Research | 2010

Zoledronic acid delays disease progression of bone metastases from hepatocellular carcinoma

Yoshio Katamura; Yoshimasa Hashimoto; Yuki Kimura; Tomokazu Kawaoka; Shintaro Takaki; Koji Waki; Akira Hiramatsu; Yoshiiku Kawakami; Shoichi Takahashi; Masahiro Kenjo; Kazuaki Chayama

Aim:  We conducted a retrospective cohort study to investigate the efficacy of combination therapy with radiotherapy (RT) and zoledronic acid for bone metastases from hepatocellular carcinoma (HCC). Additionally, we investigated the efficacy of zoledronic acid for non‐irradiated bone metastases.


Journal of Medical Virology | 2011

Prediction of response to peginterferon‐alfa‐2b plus ribavirin therapy in Japanese patients infected with hepatitis C virus genotype 1b

Yoshimasa Hashimoto; Hidenori Ochi; Hiromi Abe; Yasufumi Hayashida; Masataka Tsuge; Fukiko Mitsui; Nobuhiko Hiraga; Michio Imamura; Shoichi Takahashi; C. Nelson Hayes; Waka Ohishi; Michaki Kubo; Tatsuhiko Tsunoda; Naoyuki Kamatani; Yusuke Nakamura; Kazuaki Chayama

Variation at the IL‐28B locus was recently reported to be a significant predictive factor of viral response to pegylated‐interferon plus ribavirin combination therapy against chronic hepatitis C. Predictive factors for the effect of therapy, including IL‐28B polymorphism rs8099917 and viral and clinical factors were investigated. A total of 288 patients were enrolled who were chronically infected with hepatitis C virus (HCV) genotype 1b and treated with combination therapy. Among them, 87 patients completed 48 weeks of therapy without dose reduction or discontinuation. In multivariate regression analysis, the rs8099917 TT genotype was the only independent factor significantly associated with sustained viral response (P = 0.016, OR 61.5), whereas substitutions at amino acid 70 (aa 70) of the HCV core protein (P = 0.038, OR 5.9) and non‐TT genotypes (P = 0.002, OR 17.2) were associated with nonvirological response. Both factors were also associated with viral dynamics during the initial stage of the therapy. Correlation analysis revealed that rs8099917 genotype was correlated with γ‐glutamyl transpeptidase, hyaluronic acid, and HCV core aa 70. In conclusion, host (IL‐28B polymorphism) and viral (aa 70) factors independently affect response to combination therapy. J. Med. Virol. 83:981–988, 2011.


Scandinavian Journal of Gastroenterology | 2010

Prolongation of interferon therapy for recurrent hepatitis C after living donor liver transplantation: analysis of predictive factors of sustained virological response, including amino acid sequence of the core and NS5A regions of hepatitis C virus.

Tomokazu Kawaoka; Nobuhiko Hiraga; Shoichi Takahashi; Shintaro Takaki; Fukiko Mitsui; Masataka Tsuge; Yuko Nagaoki; Yuki Kimura; Yoshimasa Hashimoto; Yoshio Katamura; Akira Hiramatsu; Koji Waki; Michio Imamura; Yoshiiku Kawakami; Hirotaka Tashiro; Hideki Ohdan; Kazuaki Chayama

Abstract Objective. The aim of the present retrospective study was to evaluate the therapeutic efficacy and predictive factors of prolongation of treatment with peginterferon (PEGIFN) combined with ribavirin (RBV) for recurrent hepatitis C after living donor liver transplantation (LDLT). Methods. Fifty-three patients underwent LDLT due to HCV-related end-stage liver disease. Sixteen patients were removed from the study as a result of early death (n = 14), no recurrence of HCV (n = 1) and refusal of antiviral therapy (n = 1). Therapy is ongoing in another 10 patients. The remaining 27 patients were available to establish the efficacy of IFN therapy. HCV genotype was 1b in 24 patients. All patients with genotype 1b were treated with IFN therapy for at least 48 weeks after HCV RNA levels had become undetectable. Amino acid substitutions in the HCV core region and NS5A region were analyzed by direct sequencing before LDLT. Results. The rate of sustained virological response (SVR) was 37.0% (10/27). SVR rate in patients with genotype 1 was 29.2% (7/24) and 100% (3/3) in patients with genotype 2. Most patients with genotype 1b whose HCV RNA reached undetectable levels achieved SVR (87.5%; 7/8). However, mutation of the HCV core region and number of ISDR mutations were not associated with SVR rate in LDLT in our study. Conclusions. Prolonged IFN therapy for more than 48 weeks after HCV RNA reached undetectable levels might prevent virological relapse of HCV.


Hepatology Research | 2010

Transcatheter chemoembolization for unresectable hepatocellular carcinoma and comparison of five staging systems

Tomokazu Kawaoka; Shintaro Takaki; Yoshimasa Hashimoto; Yoshio Katamura; Akira Hiramatsu; Koji Waki; Shoichi Takahashi; Koji Kamada; Mikiya Kitamoto; Toshio Nakanishi; Masaki Ishikawa; Masashi Hieda; Hideaki Kakizawa; Junko Tanaka; Kazuaki Chayama

Aim:  We compared the ability of five staging system to predict survival in patients with hepatocellular carcinoma (HCC) treated with chemoembolization.


Hepatology Research | 2013

Percutaneous transhepatic sclerotherapy for recurrent bleeding ileal varices diagnosed by capsule endoscopy and computed tomography during percutaneous transhepatic venography

Yoshimasa Hashimoto; Hajime Amano; Akira Fukumoto; Mio Amano; Shintaro Sagami; Kentaro Yamao; Tomohiro Iiboshi; Seiji Onogawa; Naomichi Hirano; Keiji Hanada; Fumiaki Hino

We report a case of acute uncontrolled gastrointestinal bleeding in a patient with liver cirrhosis. A 64‐year‐old man was admitted to our hospital for further investigation of blood in stools. Preliminary examination by computed tomography (CT) as well as upper and lower endoscopy could not detect the bleeding source. Exploratory laparotomy was considered difficult due to potential easy bleeding and adhesions caused by past abdominal surgery. The hemoglobin level was normalized by blood transfusion. Capsule endoscopy (CE) identified ileal varices. The top of these ileal varices was red, prompting their identification as the source of bleeding. Percutaneous transhepatic venography (PTV) confirmed the presence of many varices in the branch of the superior mesenteric vein, although the bleeding source could not be identified. CT during PTV identified varices protruding into the ileal lumen, which were managed subsequently by percutaneous transhepatic sclerotherapy (PTS). The procedure stopped the bleeding completely. CE proved less invasive and effective in detecting obscure gastrointestinal bleeding. CT during PTV followed by PTS is suitable for diagnosis and treatment of bleeding varices in patients with portal hypertension.


Hepatology Research | 2011

Clinical outcome of esophageal varices after hepatic arterial infusion chemotherapy for advanced hepatocellular carcinoma with major portal vein tumor thrombus

Hideaki Kodama; Eisuke Murakami; Daisuke Miyaki; Yuko Nagaoki; Yoshimasa Hashimoto; Takahiro Azakami; Yoshio Katamura; Tomokazu Kawaoka; Shintaro Takaki; Akira Hiramatsu; Koji Waki; Michio Imamura; Yoshiiku Kawakami; Shoichi Takahashi; Masaki Ishikawa; Hideaki Kakizawa; Kazuo Awai; Masahiro Kenjo; Yasushi Nagata; Kazuaki Chayama

Aim:  To analyze the clinical outcome of esophageal varices (EV) after hepatic arterial infusion chemotherapy (HAIC) in patients with advanced hepatocellular carcinoma (HCC) and major portal vein tumor thrombus (Vp3/4).


Intervirology | 2012

Achievement of Sustained Viral Response after Switching Treatment from Pegylated Interferon α-2b to α-2a and Ribavirin in Patients with Recurrence of Hepatitis C Virus Genotype 1 Infection after Liver Transplantation: A Case Report

Tomokazu Kawaoka; Nobuhiko Hiraga; Shoichi Takahashi; Shintaro Takaki; Masataka Tsuge; Yuko Nagaoki; Yoshimasa Hashimoto; Yoshio Katamura; Daiki Miki; Akira Hiramatsu; Koji Waki; Michio Imamura; Yoshiiku Kawakami; Hidenori Ochi; Hirotaka Tashiro; Hideki Ohdan; Kazuaki Chayama

We report a case in which sustained viral response was achieved after switching treatment from pegylated interferon (PEG-IFN) α-2b to α-2a and ribavirin (RBV) in patients with recurrence of hepatitis C virus (HCV) infection after living donor liver transplantation. The patient was a 62-year-old man with liver cirrhosis due to HCV genotype 1b infection. The patient had 8 amino acid (aa) substitutions in the interferon sensitivity-determining region, and had substitutions for mutant and wild-type at aa70 and aa91, respectively, in the core region. The patient had minor genotype (GG) IL28B single nucleotide polymorphisms (rs8099917). He had initially received interferon α-2b and RBV for 2 years, and later developed hepatocellular carcinoma (HCC). After surgical resection of HCC, he subsequently received PEG-IFN α-2b and RBV for 1.5 years, without undetectable viremia during the treatment course. Due to recurrence of HCC, the patient received a living donor liver transplantation. Later on, hepatitis C relapsed. For the management of relapse, he received another course of PEG-IFN α-2b and RBV. However, breakthrough viremia occurred. PEG-IFN was thus switched from α-2b to α-2a and RBV for another 17 months. The patient eventually achieved a sustained viral response.


Hepatology Research | 2011

Eradication of hepatitis C virus genotype 1 after liver transplantation by interferon therapy before surgery: Report of three patients with analysis of interleukin‐28 polymorphism, hepatitis C virus core region and interferon‐sensitivity determining region

Tomokazu Kawaoka; Daisuke Miyaki; Eisuke Murakami; Takahiro Azakami; Shintaro Takaki; Yuko Nagaoki; Yoshimasa Hashimoto; Yoshio Katamura; Akira Hiramatsu; Koji Waki; Nobuhiko Hiraga; Daiki Miki; Masataka Tsuge; Michio Imamura; Yoshiiku Kawakami; Shoichi Takahashi; Hidenori Ochi; Hirotaka Tashiro; Hideki Ohdan; Kazuaki Chayama

The achievement of sustained viral response (SVR) with interferon (IFN) therapy before liver transplantation (LT) is difficult due to liver dysfunction, pancytopenia and frequent side‐effects. Here, we report eradication of hepatitis C virus (HCV) genotype 1 after LT in three patients by IFN therapy before surgery. All three patients achieved virological response (VR), namely, fall in serum HCV RNA titer below the detection limit of real‐time polymerase chain reaction (PCR) during IFN administration. However, HCV RNA rebound after cessation of treatment in all three patients; namely, they could not achieve SVR despite treatment with pegylated (PEG) IFN plus ribavirin. All three patients had wild‐type amino acids (a.a.) at either aa70 or aa91 in the core region. Genotyping of IL‐28 single nucleotide polymorphisms (rs8099917) showed TT genotype in two patients and TG genotype in one. All three patients developed multiple hepatocellular carcinomas during the clinical course, and requested living donor LT using liver grafts from their relatives. The patients were treated with IFN to immediately before LT, at which time they remained negative for HCV RNA in serum by real‐time PCR. The three patients were followed‐up for 14–15 months after LT, during which they remained negative for HCV RNA despite no further IFN therapy. In conclusion, it is possible to eradicate HCV after LT by inducing VR with continuous IFN therapy to before LT in spite of viral and host evidences reflecting low susceptibility to IFN treatment.


Journal of Gastroenterology | 2011

Clinical features and prognosis in patients with hepatocellular carcinoma that developed after hepatitis C virus eradication with interferon therapy

Yuko Nagaoki; Daisuke Miyaki; Eisuke Murakami; Yoshimasa Hashimoto; Yoshio Katamura; Takahiro Azakami; Tomokazu Kawaoka; Shintaro Takaki; Akira Hiramatsu; Koji Waki; Michio Imamura; Yoshiiku Kawakami; Shoichi Takahashi; Kazuaki Chayama

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