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Featured researches published by Atsutake Okamoto.


Journal of Hepato-biliary-pancreatic Surgery | 2009

Biliopancreatic reflux-pathophysiology and clinical implications.

Terumi Kamisawa; Masanao Kurata; Goro Honda; Kouji Tsuruta; Atsutake Okamoto

The common bile duct and the main pancreatic duct open into the duodenum, where they frequently form a common channel. The sphincter of Oddi is located at the distal end of the pancreatic and bile ducts; it regulates the outflow of bile and pancreatic juice. In patients with a pancreaticobiliary maljunction, the action of the sphincter does not functionally affect the junction. Therefore, in these patients, two-way regurgitation (pancreatobiliary and biliopancreatic reflux) occurs. This results in various pathological conditions of the biliary tract and the pancreas. Biliopancreatic reflux could be confirmed by: operative or postoperative T-tube cholangiography; CT combined with drip infusion cholangiography; histological detection of gallbladder cancer cells in the main pancreatic duct; and reflux of bile on the cut surface of the pancreas. Biliopancreatic reflux occurs frequently in patients with a long common channel. Although the true prevalence, degree, and pathophysiology of biliopancreatic reflux remain unclear, biliopancreatic reflux is related to the occurrence of acute pancreatitis. Obstruction of a long common channel easily causes bile flow into the pancreas. Even if no obstruction is present, biliopancreatic reflux can still result in acute pancreatitis in some cases.


Pancreatology | 2007

Tumor size significantly correlates with postoperative liver metastases and COX-2 expression in patients with resectable pancreatic cancer.

Gaku Matsumoto; Mariko Muta; Koji Tsuruta; Shinichiro Horiguchi; Katsuyuki Karasawa; Atsutake Okamoto

Background/Aim: Local treatment often fails in patients with resectable pancreatic cancer due to the postoperative development of distant metastases, especially liver metastases. We determined the prognostic factors for postoperative liver metastases in pancreatic cancer patients following surgical resection with combined radiotherapy. Methods: Sixty-four patients with nonmetastatic, resectable pancreatic cancer were entered into this study. All of these patients had pancreatic resection surgery combined with radiotherapy. The development of postoperative liver metastases was carefully followed, and the survival ratio was evaluated using the Kaplan-Meier method. The prognostic importance of clinicopathological factors and molecular characteristics was analyzed by the Cox proportional hazards model. The correlation study was performed using Fisher’s exact test. Results: Tumor size, curability, and histological type of differentiation were statistically significant independent prognostic factors. On multivariate analysis, curability and histological type of differentiation were statistically significant. Only tumor size (≧3 cm) was significantly correlated with postoperative liver metastases, as well as cyclooxygenase-2 expression. Conclusions: There were three significant prognostic factors in patients with resectable pancreatic cancer who had local therapy. Patients who have a large tumor require particularly careful follow-up for postoperative liver metastases.


Case Reports in Gastroenterology | 2009

Metachronous Carcinomas of the Biliary Tract in a Patient Treated Three Times with Curative Surgery

Masanao Kurata; Atsutake Okamoto; Tomoyoshi Suzuki; Gaku Matsumoto; Koji Tsuruta; Goro Honda; Tetsuo Nemoto

We here report on a case of metachronous multicentric carcinomas of the biliary tract treated 3 times with curative surgery over 23 years. A 28-year-old woman underwent cholecystectomy because of papillary carcinoma of the gallbladder. After 17 years, 3 carcinomas developed in the biliary tract: intrahepatic cholangiocarcinoma of the left liver, common bile duct carcinoma, and remnant cystic duct carcinoma. They were successfully removed via left hepatectomy combined with pylorus-preserving pancreatoduodenectomy. Furthermore, another intrahepatic cholangiocarcinoma developed 6 years after the second surgery, which was removed again via partial resection of the posterior segment of the liver. Histological findings of carcinomas represented various grades of cell differentiation. No predisposition toward carcinogenesis was found, since neither pancreaticobiliary maljunction nor primary sclerosing cholangitis was present, and the overexpression of cyclooxygenase-2 was negative in all resected specimens. Close monitoring for recurrence is warranted for early detection of metachronous carcinoma that might be effectively treated with repeated resection.


Surgery Today | 2006

Alveolar echinococcosis of the liver in a tokyo resident with an unknown route of infection : Report of a case

Yoshihisa Shimada; Tatsuro Yamaguchi; Gaku Matsumoto; Koji Tsuruta; Atsutake Okamoto; Takeo Mori; Tsunekazu Hijima

We report the case of a 45-year-old Tokyo man who developed alveolar echinococcosis of the liver, which is an extremely rare disorder in Japan, except for Hokkaido, Japans northernmost island. The findings of multiple clustered cysts on computed tomography were unlike those of any hepatic tumors we had previously encountered. T2-weighted magnetic resonance imaging revealed the characteristic findings of small cysts with a very high signal intensity. The tumors were successfully removed by a hepatic resection. The patient lives in Tokyo, but has visited Hokkaido many times. The exact route of infection in this patient remains unclear. Sliced raw venison, which he reported eating on every visit to Sapporo in Hokkaido, represented the only potential route of infection we could identify. This meat may have somehow become contaminated with embryonated eggs. Nowadays, even city inhabitants are at risk of developing rare diseases due to the rapid development of transportation systems.


Surgery Today | 1972

Littré’s femoral hernia causing intestinal fistula

Kyotaro Kanazawa; Koichi Ishikawa; Rikio Shoji; Atsutake Okamoto

AbstructLittré’s hernia is one of the rarest forms of hernia, characterized to contain the Meckel’s diverticulum as its sole content. The Meckel’s diverticulum in the hernial sac can be involved by those complications which occur in the diverticulum in the free abdominal cavity.A case of Littré’s femoral hernia in a 75 years old man with formation of an intestinal fistula as a result of inflammation of the Meckel’s diverticulum, probably, following mechanical trauma exerted by a phytogenic fibre, was reported, and the previous literatures were reviewed. Consequently, it was confirmed that signs and symptoms of Littré’s hernia with complications are less severe and non-characteristic compared to ordinary types, and hence its preoperative diagnosis is very difficult.


Journal of Hepato-biliary-pancreatic Surgery | 2009

Endocrine cells in ampullary carcinoma.

Terumi Kamisawa; Yuyang Tu; Naoto Egawa; Kouji Tsuruta; Atsutake Okamoto; Nobuaki Funata

BACKGROUND/PURPOSE As ampullary carcinoma originates from four anatomical regions, it may have different behaviors depending on its origin. We documented the presence of endocrine cells found in ampullary carcinoma, and we studied the clinicopathological implications of their presence. METHODS We immunohistochemically examined the presence of an endocrine component in 62 surgically resected specimens of ampullary carcinoma, and we studied the clinicopathological differences between endocrine component-positive cases and endocrine component-negative cases. RESULTS Endocrine cells were detected in 16 cases (26%); 11 cases had many endocrine cells, and five cases had scattered endocrine cells. Serotonin-positive cells were detected in all 16 cases, in which six cases had many positive cells. Several somatostatin-positive cells were detected in three cases. Endocrine cells were detected in ampulloduodenal polypoid lesions (two cases) and ampullopancreaticobiliary ducts (14 cases). The histology of 15 of the 16 endocrine component-positive ampullary carcinomas was the intestinal type. Pancreatic invasion and lymph node involvement were observed less frequently in endocrine component-positive cases (P < 0.01). There were no significant differences with respect to immunoreactivity for carbohydrate antigen (CA) 19.9, carcinembryonic antigen (CEA), and p53 overexpression, and K-ras mutations. CONCLUSIONS Endocrine component-positive ampullary carcinoma seemed to be derived from the ampullopancreaticobiliary common duct or the ampulloduodenum, and to behave less aggressively than endocrine component-negative carcinoma.


Journal of Hepato-biliary-pancreatic Surgery | 2007

Rectal cancer metastasis to the head of the pancreas treated with pancreaticoduodenectomy

Nobuaki Matsubara; Hiroyuki Baba; Atsutake Okamoto; Masanao Kurata; Koji Tsuruta; Nobuaki Funata; Kazuyuki Ashizawa


Hepato-gastroenterology | 2009

Biliary lesions associated with autoimmune pancreatitis.

Terumi Kamisawa; Kensuke Takuma; Hajime Anjiki; Naoto Egawa; Masanao Kurata; Goro Honda; Kouji Tsuruta; Atsutake Okamoto


Journal of Translational Medicine and Research | 2015

The process of diagnosing pancreaticobiliary maljunction

Yuka Endo; Terumi Kamisawa; Sawako Kuruma; Taku Tabata; Kazuro Chiba; Satomi Koizumi; Masanao Kurata; Goro Honda; Atsutake Okamoto


/data/revues/00165107/v63i5/S0016510706015240/ | 2011

Acute Pancreatitis Associated with a Long Common Channel

Terumi Kamisawa; Naoto Egawa; Hitoshi Nakajima; Kouji Tsuruta; Atsutake Okamoto

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Naoto Egawa

Tokyo Metropolitan Matsuzawa Hospital

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Nobuaki Funata

Tokyo Medical and Dental University

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Takeo Mori

Tokyo Medical and Dental University

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