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Dive into the research topics where Tomoyuki Minami is active.

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Featured researches published by Tomoyuki Minami.


International Journal of Oncology | 2011

Statins induce apoptosis and inhibit proliferation in cholangiocarcinoma cells

Michihiro Kamigaki; Tamito Sasaki; Masahiro Serikawa; Motoki Inoue; Kenso Kobayashi; Hiroshi Itsuki; Tomoyuki Minami; Masanobu Yukutake; Akihito Okazaki; Takashi Ishigaki; Yasutaka Ishii; Keiichi Kosaka; Kazuaki Chayama

Given the poor prognosis for cholangiocarcinoma, new and effective treatments are urgently needed. HMG-CoA reductase inhibitors (statins) reportedly exert anticancer effects in a variety of diseases, but there have been no reports of these effects in cholangiocarcinoma. In this study, we investigated the utility of statins for cholangiocarcinoma treatment. Proliferation suppression by pitavastatin and atorvastatin was investigated in the human cholangiocarcinoma cell lines HuCCT1 and YSCCC while changes in the cell cycle and intracellular signals were examined by FACS and Western blotting, respectively. Additive proliferation suppression by statins and pre-existing anticancer drugs was also investigated. HuCCT1 and YSCCC cell proliferation was dramatically suppressed by incubation with statins for 72 h or longer. Cell cycle analysis revealed a reduction in the G2M fraction and an increase in the sub-G1 fraction in statin-treated cells, while Western blotting showed increased levels of cleaved caspase-3 and a reduction in p-ERK. Furthermore, statins in combination with gemcitabine, cisplatin and 5-FU showed additive proliferation suppression. In this study, treatment of human cholangiocarcinoma cells with statins induced apoptosis via suppression of the classical MAPK pathway. Together, these results suggest that statins may be a new cholangiocarcinoma treatment option that could potentially enhance the anticancer effect of pre-existing anticancer drugs.


International Journal of Oncology | 2013

Elevated expression of cyclooxygenase-2 and microsomal prostaglandin E synthase-1 in primary sclerosing cholangitis : Implications for cholangiocarcinogenesis

Yasutaka Ishii; Tamito Sasaki; Masahiro Serikawa; Tomoyuki Minami; Akihito Okazaki; Masanobu Yukutake; Takashi Ishigaki; Keiichi Kosaka; Teruo Mouri; Satoshi Yoshimi; Akinori Shimizu; Tomofumi Tsuboi; Kazuaki Chayama

Cholangiocarcinoma (CCA) occurs frequently in primary sclerosing cholangitis (PSC). Cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) induced by inflammation are believed to mediate prostaglandin E2 (PGE2) production thereby promoting carcinogenesis. Their expression in PSC-associated CCA tissues and non-neoplastic bile duct epithelial cells (BDECs) in PSC was investigated. COX-2 and mPGES-1 levels in 15 PSC patients (7 with CCA) were scored using immunohistochemical staining. The results were compared with those obtained in CCA tissues and non-neoplastic BDECs (controls) of 15 sporadic CCA patients. Non-neoplastic BDECs from large and small bile ducts were investigated separately. The mRNA expression levels of COX-2 and mPGES-1 in CCA tissues were analyzed by quantitative polymerase chain reaction. Ki-67 immunostaining was performed to evaluate cell proliferation. COX-2 was strongly expressed in PSC-associated CCA tissues and non-neoplastic BDECs in PSC. This expression was significantly upregulated in both compared with sporadic CCA tissues and non-neoplastic BDECs in sporadic CCA (both P<0.01). mPGES-1 was expressed at moderate to strong levels in PSC. Compared with controls, the expression was significantly higher in non-neoplastic small BDECs (P<0.01). COX-2 mRNA levels were significantly higher in PSC-associated tissues than in sporadic CCA tissues (P<0.01). Conversely, no differences were observed in mPGES-1 mRNA levels. Ki-67 labeling indices were higher in PSC-associated CCA tissues and non-neoplastic BDECs in PSC than in controls. In conclusion, COX-2 and mPGES-1 were highly expressed in PSC-associated CCA tissues and non-neoplastic BDECs in PSC, suggesting the involvement of COX-2 and mPGES-1 in cholangiocarcinogenesis.


Journal of Gastroenterology and Hepatology | 2014

A comparative study of 4 Fr versus 6 Fr nasobiliary drainage catheters: a randomized, controlled trial

Takashi Ishigaki; Tamito Sasaki; Masahiro Serikawa; Tomoyuki Minami; Akihito Okazaki; Masanobu Yukutake; Yasutaka Ishii; Keiichi Kosaka; Teruo Mouri; Satoshi Yoshimi; Kazuaki Chayama

Despite the benefits of endoscopic nasobiliary drainage (NBD) in endoscopic retrograde cholangiopancreatography (ERCP), post‐ERCP pancreatitis (PEP) and nose/throat discomfort can result. We aimed to determine whether the use of a smaller catheter alleviates these complications.


Journal of Hepato-biliary-pancreatic Sciences | 2014

Antibiotic prophylaxis for endoscopic retrograde chlangiopancreatography increases the detection rate of drug‐resistant bacteria in bile

Tomoyuki Minami; Tamito Sasaki; Masahiro Serikawa; Takashi Ishigaki; Yoshiaki Murakami; Kazuaki Chayama

No consensus has yet been reached regarding the utility of antibiotic prophylaxis for endoscopic retrograde cholangiopancreatography (ERCP). However, there has been little discussion of potential adverse effects of antibiotic use. This study investigated the impact of antibiotic prophylaxis on overall levels of bacterial infiltration of the biliary tract and the prevalence of drug‐resistance among that population.


Gastroenterology Research and Practice | 2014

Occupational Radiation Exposure during Endoscopic Retrograde Cholangiopancreatography and Usefulness of Radiation Protective Curtains

Tomoyuki Minami; Tamito Sasaki; Masahiro Serikawa; Michihiro Kamigaki; Masanobu Yukutake; Takashi Ishigaki; Yasutaka Ishii; Teruo Mouri; Satoshi Yoshimi; Akinori Shimizu; Tomofumi Tsuboi; Keisuke Kurihara; Yumiko Tatsukawa; Eisuke Miyaki; Kazuaki Chayama

Objective. To evaluate the effectiveness of radiation protective curtains in reducing the occupational radiation exposure of medical personnel. Methods. We studied medical staff members who had assisted in 80 consecutive therapeutic endoscopic retrograde cholangiopancreatography (ERCP) procedures. Use of radiation protective curtains mounted to the X-ray tube was determined randomly for each procedure, and radiation doses were measured with electronic pocket dosimeters placed outside the protective apron. Results. When protective curtains were not used, the mean radiation doses to endoscopists, first assistants, second assistants, and nurses were 340.9, 27.5, 45.3, and 33.1 µSv, respectively; doses decreased to 42.6, 4.2, 13.1, and 10.6 µSv, respectively, when protective curtains were used (P < 0.01). When the patient had to be restrained during ERCP (n = 8), the radiation dose to second assistants without protective curtains increased by a factor of 9.95 (P < 0.01) relative to cases in which restraint was not required. Conclusions. During ERCP, not only endoscopists, but also assistants and nurses were exposed to high doses of radiation. Radiation exposure to staff members during ERCP was reduced with the use of protective curtains.


Scandinavian Journal of Gastroenterology | 2014

Timing of radiological improvement after steroid therapy in patients with autoimmune pancreatitis.

Masanobu Yukutake; Tamito Sasaki; Masahiro Serikawa; Tomoyuki Minami; Akihito Okazaki; Takashi Ishigaki; Yasutaka Ishii; Keiichi Kosaka; Teruo Mouri; Satoshi Yoshimi; Akinori Shimizu; Tomofumi Tsuboi; Keizo Tanitame; Kazuaki Chayama

Abstract Objective. We retrospectively studied the timing of radiological improvement after steroid therapy in patients with autoimmune pancreatitis (AIP). Material and methods. Patients with AIP (n = 31) received steroids followed by diagnostic imaging within 1 month. Pancreatic swelling, pancreatic and bile duct features, and apparent diffusion coefficient (ADC) were compared before and after treatment. The period from treatment initiation to evaluation was divided into five phases: early phase (days 3–5), week 1 (days 6 and 7), week 2 (days 8–14), week 3 (days 15–21), and week 4 (days 22–28). Five gastroenterologists evaluated pancreatic swelling and duct features (good/intermediate/no response), and the “good response” rate (response rate) was calculated for each phase. In addition, pancreatic volumes were measured with a 3D workstation before and after treatment, and the percentage change in volume was calculated. ADC values were calculated in 14 patients. Results. The median ratio of pancreatic volume after relative to before treatment was 0.89, 0.79, 0.67, 0.59, and 0.47 for early phase, week 1, week 2, week 3, and week 4, respectively. The response rate of the pancreatic swelling was 37.5%, 57.1%, 83.3%, 100%, and 100%; response rate of the pancreatic duct was 0%, 20%, 75%, 75% and 100%; and response rate of the bile duct was 0%, 66.7%, 83.3%, 100%, and 80%. The ADC increased after treatment in all 14 patients, including the 7 patients evaluated in the early phase. Conclusions. Evaluation of pancreatic swelling and duct features is recommended in week 2 and thereafter. The ADC increased soon after treatment initiation, suggesting its usefulness for evaluating early treatment responses.


Archive | 2018

Role of Ultrasonography for the Diagnosis of Pancreaticobiliary Maljunction and Congenital Biliary Dilatation

Keiji Hanada; Akinori Shimizu; Tomoyuki Minami

PBM is one of the anomalous conditions in which the bile duct and the pancreatic duct merge outside the duodenal wall, which causes continuous pancreaticobiliary reflux (PR). PBM is classified into two groups as follows: PBM with biliary dilatation (congenital biliary dilatation, CBD) and PBM without dilatation. US must be the best method for the diagnosis of PBM associated with CBD, revealing extrahepatic or intrahepatic bile duct dilatation. In adults, the maximum inner diameter of extrahepatic bile duct (MDEBD) was recently reported. MDEBD positively correlated with age. In cases of PBM without bile duct dilatation, thickening of the gallbladder wall as a characteristic sonographic feature has been reported. Hyperplastic changes with increased cell proliferation in gallbladder mucosa induced by PR could reflect as thickening of the gallbladder. A high confluence of pancreaticobiliary ducts (HCPBD) has been defined as a disease state. In HCPBD cases, PR and hyperplastic changes in gallbladder were observed. US is an important image modality to give clues to the diagnosis in cases with PBM, CBD, and HCPBD, because it can reveal sonographic characteristics such as gallbladder wall thickening and/or mild dilatation of the extrahepatic bile duct.


Clinical Journal of Gastroenterology | 2018

A case of mixed adenoneuroendocrine carcinoma of the pancreas mimicking intraductal papillary mucinous carcinoma

Hideki Mori; Keiji Hanada; Tomoyuki Minami; Shigeki Yano; Motomitsu Fukuhara; Hirotsugu Maruyama; Akinori Shimizu; Naomichi Hirano; Fumiaki Hino; Hironobu Amano; Shuji Yonehara

A previously healthy 52-year-old man was referred to our hospital for further evaluation of main pancreatic duct dilatation. The preoperative work-up was consistent with intraductal papillary mucinous carcinoma (IPMC) derived from a mixed type intraductal papillary mucinous neoplasm (IPMN), because multilocular cysts with enhancing thickened pancreatic head walls and dilated pancreatic ducts lined with dysplastic mucinous epithelium, with papillary proliferation from the pancreatic body to the tail, were observed; in addition, the pancreatic juice cytology was class V, which is suggestive of adenocarcinoma. Total pancreatectomy was performed because a definite mass was not found before surgical resection and the tumors could have spread to the tail. The pathological diagnosis was mixed adenoneuroendocrine carcinoma of the pancreatic head. IPMN with high- or low-grade dysplasia was not observed anywhere in the pancreatic duct. The pancreatic ductal adenocarcinoma consisted of large caliber malignant glands with intraluminal flat or papillary structures; therefore, we were unable to recognize a definite pancreatic mass before surgical resection, and suspected an IPMC derived from a mixed type IPMN.


International Journal of Surgery Case Reports | 2017

Mixed adenoneuroendocrine carcinoma derived from the cystic duct: A case report

Yuki Takemoto; Tomoyuki Abe; Hironobu Amano; Keiji Hanada; Akihito Okazaki; Tomoyuki Minami; Tsuyoshi Kobayashi; Masahiro Nakahara; Shuji Yonehara; Hideki Ohdan; Toshio Noriyuki

Highlights • We report here an extremely rare case of mixed adenoneuroendocrine carcinomas (MANECs) derived from cystic duct. Histologically, the tumor had components of both well-differentiated tubular adenocarcinoma and neuroendocrine carcinoma with massive venous invasion.• R0 resection was established, but the risk of recurrence in liver was estimated to be significantly high, due to the detected venous invasion of the neuroendocrine carcinoma in the resection margin of the hepatic duct. Eight months after surgery, multiple liver metastases were discovered, and treatment with adjuvant chemotherapy was initiated.• Though standards of diagnosis and treatment for MANECs of the bile duct have not been established, multidisciplinary therapy is necessary to improve outcomes.


Journal of Biological Chemistry | 2001

Deoxycytidyl Transferase Activity of the Human REV1 Protein Is Closely Associated with the Conserved Polymerase Domain

Yuji Masuda; Mamoru Takahashi; Noriko Tsunekuni; Tomoyuki Minami; Masaharu Sumii; Kiyoshi Miyagawa; Kenji Kamiya

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