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Dive into the research topics where Itaru Ozeki is active.

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Featured researches published by Itaru Ozeki.


Oncogene | 2000

Frequent hypermethylation of CpG islands and loss of expression of the 14-3-3 σ gene in human hepatocellular carcinoma

Norikazu Iwata; Hiroyuki Yamamoto; Shigeru Sasaki; Fumio Itoh; Hiromu Suzuki; Takefumi Kikuchi; Hiroyuki Kaneto; Shouhei Iku; Itaru Ozeki; Yoshiyasu Karino; Toshihiro Satoh; Joji Toyota; Masaaki Satoh; Takao Endo; Kohzoh Imai

The 14-3-3 σ gene has been implicated in G2/M cell cycle arrest by p53. Frequent inactivation of the 14-3-3 σ gene by hypermethylation of CpG islands has recently been reported in human breast carcinoma. The aim of this study was to examine the methylation status of CpG islands of the 14-3-3 σ gene in hepatocellular carcinoma (HCC). The methylation status of the 14-3-3 σ gene was evaluated in four normal liver tissues and 19 paired specimens of carcinoma and adjacent non-tumorous liver tissues using bisulfite-single strand conformation polymorphism (bisulfite-SSCP), a combination of sodium bisulfite modification and fluorescence-based polymerase chain reaction (PCR)-SSCP. The 14-3-3 σ protein expression was examined by immunohistochemical staining. Hypermethylation of CpG islands of the 14-3-3 σ gene was detected in 89% (17/19) of the HCC tissues but not in any of the four normal liver tissues. All of the 14 methylation-positive HCC samples analysed by immunohistochemistry showed loss of 14-3-3 σ expression, while both of the methylation-negative HCC samples retained the expression, and a significant correlation was found between methylation and loss of expression. Lower levels of methylation were detected in adjacent non-tumorous liver tissues (6/16 in cirrhotic tissues and 1/3 in chronic hepatitis tissues), but the 14-3-3 σ expression was retained in all of these tissues. In a methylation-positive HCC cell line, HLE, 5-aza-2′-deoxycytidine (5-aza-dC)-induced demethylation of CpG islands led to reactivation of gene expression, indicating that hypermethylation plays a causal role in inactivation of the 14-3-3 σ gene in HCC. Hypermethylation and the resulting loss of expression of the 14-3-3 σ gene corresponds to one of the most common abnormalities reported to date in HCC, suggesting their crucial role in the development and/or progression of HCC.


Gut | 2001

Detection of hypermethylation of the p16 INK4A gene promoter in chronic hepatitis and cirrhosis associated with hepatitis B or C virus

Hiroyuki Kaneto; Shigeru Sasaki; Hiroyuki Yamamoto; Fumio Itoh; Minoru Toyota; Hiromu Suzuki; Itaru Ozeki; N Iwata; T Ohmura; T Satoh; Y Karino; Joji Toyota; Masaaki Satoh; Takao Endo; M Omata; Kohzoh Imai

BACKGROUND/AIM Inactivation of the p16 INK4A(p16) tumour suppressor gene by promoter region hypermethylation has been demonstrated not only in many types of tumours, including hepatocellular carcinoma (HCC), but also in early preneoplastic lesions in the lung, colon, oesophagus, and pancreas. The aim of this study was to examine the methylation status of thep16 promoter in pre- and/or non-neoplastic liver diseases. PATIENTS/SUBJECTS/METHODS The methylation status of p16 was evaluated in 22 HCC, 17 cirrhosis, 17 chronic hepatitis, nine primary biliary cirrhosis (PBC), eight autoimmune hepatitis, seven drug induced liver disease, six fatty liver, and three normal liver tissues using methylation specific polymerase chain reaction (MSP). p16 protein expression was also examined by immunohistochemical staining. RESULTS Methylation of the p16 promoter was detected in HCC (72.7%, 16/22) and also in cirrhosis (29.4%, 5/17) and chronic hepatitis (23.5%, 4/17), all of which were positive for hepatitis B or C virus infections. Methylation was not detected in any of the other samples. All methylation positive HCC, cirrhosis, and chronic hepatitis samples showed loss of p16 expression, and a significant correlation was found between methylation and loss of expression. Analysis of serial samples from individual patients with methylation positive HCC revealed that loss of p16 expression with promoter methylation occurred in 18 of 20 patients at the stage of chronic hepatitis without clinically detectable carcinoma. CONCLUSIONS Our results suggest that methylation of the p16promoter and the resulting loss of p16 protein expression are early events in a subset of hepatocarcinogenesis and that their detection is useful in the follow up of patients with a high risk of developing HCC, such as those with hepatitis B or C viral infections.


Journal of Viral Hepatitis | 2014

Telaprevir impairs renal function and increases blood ribavirin concentration during telaprevir/pegylated interferon/ribavirin therapy for chronic hepatitis C

Yoshiyasu Karino; Itaru Ozeki; Shuhei Hige; M. Kimura; T. Arakawa; T. Nakajima; Y. Kuwata; T. Sato; T. Ohmura; Joji Toyota

We aimed to examine the relationship between renal dysfunction and anaemia that may develop during combination therapy involving pegylated interferon, ribavirin and telaprevir (PEG‐IFN/RBV/TVR) for the treatment of chronic hepatitis C. Sixty‐eight patients with genotype 1b high viral loads were treated with PEG‐IFN/RBV/TVR. Peg‐IFN and RBV doses were administered according to body weight. TVR was prescribed at 2250 mg/day for 44 patients and at 1500 mg/day for 24 patients who had low haemoglobin level (<12 g/dL). When anaemia had developed, the RBV dose was decreased. The serum TVR concentration at day 8 was measured, and the serum RBV concentration was measured serially. The estimated glomerular filtration rate (eGFR) was estimated to assess renal function. At week 1, serum TVR concentration was not correlated with a decrease in eGFR; however, the TVR dose, on a weight basis (mg/kg), and eGFR were correlated (r = 0.2691; P = 0.0265). Moreover, there was a negative correlation between eGFR and RBV serum concentration (r = −0.3694; P = 0.0025), and the serum RBV concentration and decrease in the haemoglobin were significantly correlated from week 1 to week 8. In triple therapy, the TVR dose per weight is correlated with a decline in renal function. Thus, the serum concentration of RBV increases, with a concomitant decrease in haemoglobin. It is important to adjust the doses of TVR and RBV to avoid excessive serum RBV levels and the development of severe anaemia, to achieve a good clinical effect.


Journal of Gastroenterology | 2000

Macrocystic serous cystadenoma of the pancreas : importance of co-existent tiny cysts depicted by EUS

Hiroyuki Kaneto; Takao Endo; Itaru Ozeki; Hideto Itoh; Shigeru Sasaki; Mitsuhiro Mukaiya; Ken Ikeda; Kazumitsu Koito; Kohzoh Imai

Abstract: The case of a 38-year-old man with an unusual type of serous cystadenoma of the pancreas is reported. A multilocular cystic tumor in the head of the pancreas was detected on abdominal ultrasonography and computed tomography. On endoscopic ultrasonography, the major cysts ranged from 2.0 to 4.5 cm in size. In addition to these large cysts, a few small cysts were detected. Based on these findings, this tumor was diagnosed as a macrocystic type serous cystadenoma. Because endoscopic retrograde pancreatogram showed a compression of the main pancreatic duct around the tumor, and because the size of the tumor had been increasing over a 3-year period, surgical intervention was performed. The resected tumor consisted of macrocysts, with a few small cysts, and was histologically diagnosed as serous cystadenoma. Endoscopic ultrasonography appears to provide an excellent inside image of this unusual tumor, and because of its ability to detect small cystic lesions clearly, it could be useful in the diagnosis of macrocystic serous cystadenoma.


Journal of Viral Hepatitis | 2013

Virological response and safety of 24-week telaprevir alone in Japanese patients infected with hepatitis C virus subtype 1b.

Joji Toyota; Itaru Ozeki; Yoshiyasu Karino; Yasuhiro Asahina; Namiki Izumi; Shigeo Takahashi; Yoshiiku Kawakami; Kazuaki Chayama; Naohiro Kamiya; K. Aoki; Ichimaro Yamada; Yasuaki Suzuki; Fumitaka Suzuki

Summary.  Hepatitis C virus (HCV) subtype 1b, which infects approximately 70% of Japanese carriers, is likely to be more eradicable by a telaprevir regimen than subtype 1a because of the higher genetic barrier of Val36 and Arg155 substitutions. The aims of this exploratory study were to evaluate the virological response and safety of 24‐week oral administration of telaprevir alone in chronic HCV subtype 1b infection. Fifteen treatment‐naïve patients were treated with telaprevir 750 mg every 8 h for 24 weeks. All patients were Japanese whose median age was 58.0 years (range: 45–68), and six patients (40%) were men. Median baseline HCV RNA level was 6.80 log10 IU/mL (range: 3.55–7.10). The HCV RNA levels decreased to undetectable in five patients (33%) within 8 weeks. Three patients (20%) with negative HCV RNA by Week 4 achieved end of treatment response. One patient (7%) who achieved sustained virological response had a low baseline viraemia of 3.55 log10 IU/mL. Most of the adverse events including anaemia and skin disorders were mild to moderate. Developed variants were T54A and A156V/T/F/Y with or without secondary substitutions rather than V36M ± R155K. Telaprevir alone for 24 weeks in Japanese patients with HCV subtype 1b resulted in an sustained viral response rate of 7% (1/15) and was well tolerated for 24 weeks. These results will support the implementation of further studies on oral combination of telaprevir with other direct‐acting antiviral agents in patients infected with HCV subtype 1b.


Journal of Gastroenterology | 1996

Subcapsular hematoma of the liver and pylethrombosis in the setting of cholestatic liver injury

Hirofumi Sakamoto; Mitsuo Suga; Itaru Ozeki; Toshihisa Kobayashi; Toshiaki Sugaya; Yasushi Sasaki; Naoki Azuma; Fumio Itoh; Shin-ichi Sakamoto; Akira Yachi; Kohzoh Imai

We describe a subcapsular hematoma of the liver and pylethrombosis in a patient who developed cholestasis 4 days after severe burn injury. On the 44th hospital day, severe anemia suddenly appeared with no determinable cause. This was the initial manifestation of hepatic hematoma. Cholestatic liver injury of unknown cause lasted throughout the clinical course. The patient subsequently died of hepatic failure 27 months after the burn injury. An autopsy confirmed pylephlebitis and pylethrombosis, which were considered to have contributed to the hepatic failure. This was a rare case of hepatic hematoma and pylephlebitis and pylethrombosis that developed after burn injury.


Hepatology Research | 2016

Successful achievement of sustained virological response to triple combination therapy containing simeprevir in two patients with chronic hepatitis C who had failed asunaprevir-daclatasvir combination therapy.

Itaru Ozeki; Tomoaki Nakajima; Masakatsu Yamaguchi; Mutsuumi Kimura; Tomohiro Arakawa; Yasuaki Kuwata; Takumi Ohmura; Takahiro Sato; Shuhei Hige; Yoshiyasu Karino; Joji Toyota

Patients 1 and 2 were treatment‐naive women who had genotype 1b chronic hepatitis C. Both had IL‐28B genotype TT, and amino acid substitutions of core 70 and 91 were both wild type. Search for the presence of resistance‐associated variants (RAV) in non‐structural (NS)3 and NS5A regions confirmed wild‐type D168 and L31, along with Y93H, in both patients. These patients participated in a Japanese phase III clinical study of asunaprevir and daclatasvir at the age of 52 and 67 years, respectively, and were treated with the combination regimen for 24 weeks. However, both experienced post‐treatment relapse, and then treated with triple combination therapy with simeprevir, pegylated interferon (IFN) and ribavirin at the age of 53 and 68 years, respectively, and achieved sustained virological response. A search for RAV prior to simeprevir treatment identified multiple resistance including D168E, Y93H and L31V in both patients. It has been demonstrated that, in many cases, a treatment failure with a combination of asunaprevir and daclatasvir results in acquisition of RAV in NS3 and NS5A regions and that drug‐resistant mutants, particularly those in the NS5A region, survive for a long time. In these cases, direct‐acting antivirals targeted towards the NS5A region may have a limited efficacy. The present case report is based on an idea that a regimen containing IFN with simeprevir could be a therapeutic option particularly for those who are likely to be highly sensitive and tolerable to IFN.


Hepatology Research | 2018

Analysis of HBsAg using high-sensitivity HBsAg assays in hepatitis B virus carriers in whom HBsAg seroclearance was confirmed by conventional assays.

Itaru Ozeki; Tomoaki Nakajima; Hirokazu Suii; Ryoji Tatsumi; Masakatsu Yamaguchi; Mutsuumi Kimura; Tomohiro Arakawa; Yasuaki Kuwata; Takumi Ohmura; Shuhei Hige; Yoshiyasu Karino; Joji Toyota

We investigated the utility of high‐sensitivity hepatitis B surface antigen (HBsAg) assays compared with conventional HBsAg assays.


Case Reports in Hepatology | 2017

Safety of Sofosbuvir and Ribavirin Combination Therapy in a Patient Who Developed Anemia due to Ribavirin

Hirokazu Suii; Itaru Ozeki; Ryoji Tatsumi; Masakatsu Yamaguchi; Mutsuumi Kimura; Tomohiro Arakawa; Tomoaki Nakajima; Yasuaki Kuwata; Takumi Ohmura; Shuhei Hige; Yoshiyasu Karino; Joji Toyota

Interferon (IFN) and ribavirin (RBV) combination therapy was previously the standard of care for treatment of hepatitis C virus (HCV) genotype 2 infection. But, it often induced hemolytic anemia. In 2014, sofosbuvir (SOF) was approved for the treatment of chronic HCV genotype 2 in Japan. SOF/RBV therapy is more effective against genotype 2 than IFN/RBV therapy. We report a case of a 74-year-old woman with chronic HCV genotype 2b infection. She received five treatments including RBV and IFN therapy before SOF was approved and all of them were ineffective. Therapies that included RBV induced severe anemia and led to discontinuation of treatment. With pegylated IFN/RBV therapy, the maximum change in hemoglobin (Hb) from baseline was −3.7 g/dL. However, SOF/RBV therapy was effective and she achieved sustained virologic response (SVR) with a maximum change in Hb from baseline of only −1.2 g/dL. We also found reticulocyte count was very low during treatment in this case and speculate it was one of the reasons that she developed hemolytic anemia with RBV. In conclusion, SOF/RBV therapy is effective and allowed the patient to achieve SVR. An SOF/RBV regimen is safe and effective for patients who have or are at risk of anemia induced by RBV.


Oncology Reports | 2003

Differential roles of alterations of p53, p16, and SMAD4 expression in the progression of intraductal papillary-mucinous tumors of the pancreas

Shigeru Sasaki; Hiroyuki Yamamoto; Hiroyuki Kaneto; Itaru Ozeki; Yasuyo Adachi; Hideyasu Takagi; Takeshi Matsumoto; Hideto Itoh; Tatsuya Nagakawa; Hiroyuki Miyakawa; Shunji Muraoka; Akira Fujinaga; Toshihiro Suga; Masaaki Satoh; Fumio Itoh; Takao Endo; Kohzoh Imai

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Fumio Itoh

St. Marianna University School of Medicine

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Hiroyuki Kaneto

Sapporo Medical University

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Hiroyuki Yamamoto

Sapporo Medical University

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Shigeru Sasaki

Sapporo Medical University

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Takao Endo

Sapporo Medical University

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Tomoaki Nakajima

Kyoto Prefectural University of Medicine

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