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Featured researches published by Tsunao Imamura.


Pancreatology | 2002

A case of autoimmune pancreatitis responding to steroid therapy

Takeshi Saito; Shigeki Tanaka; Hitoshi Yoshida; Tsunao Imamura; Junichi Ukegawa; Tetsuya Seki; Akitoshi Ikegami; Fuyuhiko Yamamura; Tetsuya Mikami; Yuji Aoyagi; Junichi Niikawa; Keiji Mitamura

We report a case of autoimmune pancreatitis without obvious evidence of autoimmunological participation, which responded well to steroid treatment and provided histologic and radiographic evidence for this improvement. A 68-year-old woman presented abdominal fullness, diffuse pancreatic swelling on abdominal computed tomography and ultrasonography, and diffuse narrowing of the main pancreatic duct on endoscopic retrograde pancreatography. Transgastric aspiration needle biopsy of the body of the pancreas performed under endoscopic ultrasonography showed severe atrophy of acinar cells, infiltration of T lymphocytes. She was diagnosed as having autoimmune pancreatitis without obvious evidence of autoimmunological participation. Administration of 30 mg/day of predonisolone was started. Computed tomography showed marked improvement of the diffuse swelling of the pancreas, and endoscopic retrograde pancreatograpy showed amelioration of the narrowing of the main pancreatic duct after the start of treatment. Pancreatic tissue obtained by needle biopsy after the start of treatment with predonisolone revealed marked histologic improvement, including amelioration of the fibrosis, and infiltration of inflammatory lymphocytes, and a substantial increase in the number of pancreatic acinar cells. The present report is the first to demonstrate histologic recovery of autoimmune pancreatitis after steroid therapy.


Journal of Gastroenterology | 2002

Significance of measurement of high-sensitivity C-reactive protein in acute pancreatitis

Tsunao Imamura; Shigeki Tanaka; Hitoshi Yoshida; Katsuya Kitamura; Akitoshi Ikegami; Akira Takahashi; Junichi Niikawa; Keiji Mitamura

Background: Determination of the severity of acute pancreatitis is difficult in the early phase after onset, and we often encounter difficulties in making decisions to initiate intensive care during the early phase. Therefore, there is real need for a simple and inexpensive method that can precisely evaluate the severity of acute pancreatitis. Methods: In the present study, we measured serum C-reactive protein (CRP) levels in 20 patients with acute pancreatitis, using a high-sensitivity CRP (hs-CRP) assay method. Results: CRP levels were as low as 1.0, 0.4, and 0.3 mg/dl in cases 2, 3, and 9, respectively, with severe acute pancreatitis. These three patients were hospitalized within 24 h after the onset of pancreatitis. Cases 2, 3, and 9 showed high hs-CRP levels, of 209 000, 68 600, and 154 000 ng/ml, respectively, and their interleukin (IL)-6 levels were above 500 pg/ml. The mean hs-CRP level was 222 760 ± 32 197 ng/ml in patients with severe acute pancreatitis and 22 798 ± 8216 ng/ml in patients with mild to moderate pancreatitis, with a significantly higher level in the severe cases. Cases 14, 16, and 20, with mild to moderate pancreatitis, had hs-CRP levels of 83 400, 1800, and 55 400 ng/ml, respectively. Conclusions: Measurement of hs-CRP levels is a simple and inexpensive method. The hs-CRP levels were found to significantly increase in the early phase of severe acute pancreatitis, suggesting that hs-CRP could possibly serve as an early indicator of the progression of acute pancreatitis into a serious state.


Pancreas | 2008

Ultrasonographic imaging of bile duct lesions in autoimmune pancreatitis.

Rikako Koyama; Tsunao Imamura; Chikao Okuda; Natsuko Sakamoto; Hajime Honjo; Kazuo Takeuchi

Objectives: Patients with autoimmune pancreatitis (AIP) commonly have lesions in the bile duct itself and show stenosis of the bile duct system; however, no detailed study has evaluated the ultrasonographic findings of bile duct lesions in AIP. In this study, we monitored the clinical course and imaging findings, mainly ultrasonographic, of bile duct lesions in AIP. Methods: We retrospectively analyzed the incidence of bile duct lesions, imaging findings, and clinical course in 37 patients with AIP. Results: Characteristic bile duct and gallbladder wall thickening was recognized on ultrasound in 37.8% (14/37) of AIP patients. We divided the patients into 2 types according to the ultrasonographic findings of bile duct wall thickening: (1) 3-layer type (64.3%) and (2) parenchymal-echo type (35.7%). All 14 cases were treated with prednisolone, with immediate resolution of the bile duct lesions. Conclusion: Sclerosing cholangitis is one of the extrapancreatic lesions that are commonly detected in AIP patients; it is detected on ultrasonographic imaging as characteristic wall thickening. Our ultrasonographic findings reflect the fact that bile duct wall thickening in AIP is an inflammatory process that responds to prednisolone therapy. Ultrasonography is a useful tool in detecting biliary tract lesions in AIP.


Journal of Gastroenterology | 2003

Pancreatic regeneration after ethionine-induced acute pancreatitis in rats lacking pancreatic CCK-A receptor gene expression

Takaya Sato; Junichi Niikawa; Ichiro Usui; Tsunao Imamura; Hitoshi Yoshida; Shigeki Tanaka; Keiji Mitamura

Background. We examined the effects of cholecystokinin (CCK) on the development of ethionine-induced pancreatitis and pancreatic recovery. We used Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model lacking pancreatic CCK-A receptor gene expression. Methods. Ethionine-induced pancreatitis was induced in the 7-week-old male OLETF rats and in a control group that does not lack the pancreatic CCK-A receptor, Long-Evans Tokushima Otsuka (LETO) rats. The two groups were maintained on a low-protein diet for 11 days. During the last 4 days of the low-protein diet, dl-ethionine 20 mg/100 g body weight was administered intraperitoneally once daily. Histologic and biochemical examinations of the pancreas were performed, and plasma CCK concentrations were measured on days 1, 4, and 7 after the last ethionine administration. Results. Pancreatic histologic scores for inflammation, hemorrhage, and necrosis in the LETO and OLETF rats were highest on days 1 and 4, respectively. Pancreatic weight, DNA content, and protein level per DNA content in both groups decreased during the low-protein diet, and recovery signs were delayed in the OLETF rats. The highest plasma CCK concentrations in the LETO and OLETF rats were reached on days 1 and 4, respectively. Conclusions. Ethionine-induced pancreatitis developed in the OLETF rats, and their pancreatic regeneration was delayed in comparison to that in the LETO rats. Our results suggested that CCK plays an important role in the development of pancreatitis as well as in the pancreatic repair process.


World Journal of Gastroenterology | 2016

Multicenter study of endoscopic preoperative biliary drainage for malignant distal biliary obstruction.

Naoki Sasahira; Tsuyoshi Hamada; Osamu Togawa; Ryuichi Yamamoto; Tomohisa Iwai; Kiichi Tamada; Yoshiaki Kawaguchi; Kenji Shimura; Takero Koike; Yu Yoshida; Kazuya Sugimori; Shomei Ryozawa; Toshiharu Kakimoto; Ko Nishikawa; Katsuya Kitamura; Tsunao Imamura; Masafumi Mizuide; Nobuo Toda; Iruru Maetani; Yuji Sakai; Takao Itoi; Masatsugu Nagahama; Yousuke Nakai; Hiroyuki Isayama

AIM To determine the optimal method of endoscopic preoperative biliary drainage for malignant distal biliary obstruction. METHODS Multicenter retrospective study was conducted in patients who underwent plastic stent (PS) or nasobiliary catheter (NBC) placement for resectable malignant distal biliary obstruction followed by surgery between January 2010 and March 2012. Procedure-related adverse events, stent/catheter dysfunction (occlusion or migration of PS/NBC, development of cholangitis, or other conditions that required repeat endoscopic biliary intervention), and jaundice resolution (bilirubin level < 3.0 mg/dL) were evaluated. Cumulative incidence of jaundice resolution and dysfunction of PS/NBC were estimated using competing risk analysis. Patient characteristics and preoperative biliary drainage were also evaluated for association with the time to jaundice resolution and PS/NBC dysfunction using competing risk regression analysis. RESULTS In total, 419 patients were included in the study (PS, 253 and NBC, 166). Primary cancers included pancreatic cancer in 194 patients (46%), bile duct cancer in 172 (41%), gallbladder cancer in three (1%), and ampullary cancer in 50 (12%). The median serum total bilirubin was 7.8 mg/dL and 324 patients (77%) had ≥ 3.0 mg/dL. During the median time to surgery of 29 d [interquartile range (IQR), 30-39 d]. PS/NBC dysfunction rate was 35% for PS and 18% for NBC [Subdistribution hazard ratio (SHR) = 4.76; 95%CI: 2.44-10.0, P < 0.001]; the pig-tailed tip was a risk factor for PS dysfunction. Jaundice resolution was achieved in 85% of patients and did not depend on the drainage method (PS or NBC). CONCLUSION PS has insufficient patency for preoperative biliary drainage. Given the drawbacks of external drainage via NBC, an alternative method of internal drainage should be explored.


Journal of Gastroenterology | 2003

Effect of IS-741 on ethionine-induced acute pancreatitis in rats: relation to pancreatic acinar cell regeneration

Tsunao Imamura; Junichi Niikawa; Katsuya Kitamura; Akira Takahashi; Akitoshi Ikegami; Hitoshi Yoshida; Shigeki Tanaka; Keiji Mitamura

Background: Tissue destruction arising from neutrophil infiltration of the pancreas and other organs in acute pancreatitis is supposed to be suppressed by IS-741. We studied the effect of IS-741 on acute pancreatitis induced by DL-ethionine in rats. Methods: Rats fed with a low protein diet for 11 days received daily intraperitoneal administration of DL-ethionine (20 mg/100 g) for the last 4 days of the diet. To evaluate the therapeutic effect on ethionine-induced pancreatitis, IS-741 (10 mg/kg s.c.) was administered every 8 h beginning after the second ethionine injection (IS group). An equal volume of saline was used for control rats as alternative to IS-741 (control group). The rats were killed 1, 3, 5, and 7 days after the last injection of ethionine. Blood was collected to measure concentrations of the inflammatory cytokine, interleukin-8. Histologic and biochemical examinations of the pancreas were performed. The pancreatic weight, DNA content, and protein levels were determined. The pancreas was histologically examined. Results: Pancreatic tissue in the control group showed marked infiltration of inflammatory cells, and acinar cell necrosis was widespread 1 day after the last injection of ethionine (day 1). The severity of acute pancreatitis was alleviated in rats treated with IS-741 (IS group). Pancreatic wet weight and DNA content in the IS group were higher than those in the control group on day 1. Pancreatic protein level per DNA in the IS group was higher than that in the control group on day 7. The plasma interleukin-8 level in the control group was higher than that in the IS group on day 5. Conclusions: Therapeutic administration of IS-741 ameliorated ethionine-induced acute pancreatitis in rats, and IS-741 could be a useful drug to treat patients with severe acute pancreatitis.


Internal Medicine | 2015

Adrenal Metastasis and Hemorrhage Secondary to Hepatocellular Carcinoma.

Shintaro Akiyama; Tsunao Imamura; Rikako Koyama; Tetsuo Tamura; Yuko Koizumi; Kazuo Takeuchi

A 66-year-old man was admitted to undergo treatment for the sudden onset of hypogastric pain radiating to the left flank. Based on the clinical presentation and radiological findings, left adrenal hemorrhage secondary to hepatocellular carcinoma was diagnosed. Although the patient was hemodynamically stable, anemia progressed over the first four days after admission and a blood transfusion was subsequently initiated, which was effective. According to the results of interval imaging with computed tomography, elective transcatheter embolization (TAE) was performed nine days after admission to treat the bleeding from the adrenal tumor. After TAE, the patients abdominal pain resolved, with no further progression of anemia.


Digestive Endoscopy | 2006

EFFECTIVENESS OF CYTODIAGNOSIS WITH PANCREATIC DUCT LAVAGE FLUID FOR PANCREATIC DUCTAL CARCINOMA: NEW SAMPLING TECHNIQUE

Tsunao Imamura; Rie Takeshita; Rikako Koyama; Chikao Okuda; Kazuo Takeuchi; Masamichi Matsuda; Masashi Hashimoto; Goro Watanabe; Hitoshi Yoshida; Michio Imawari

Background:  Pancreatic carcinoma is one of the most lethal cancers. Because pancreatic carcinoma is still very difficult to diagnose in its early stage, many of these patients will be considered unsuitable for surgery. If a cytological diagnosis is obtained at initial endoscopic retrograde cholangiopancreatography (ERCP), suitable treatment will be initiated without delay.


Medicine | 2014

A case report of the histologic transformation of primary follicular lymphoma of the duodenum.

Shintaro Akiyama; Koji Izutsu; Yasunori Ota; Tsunao Imamura; Osamu Ogawa; Atsushi Wake; Kazuo Takeuchi

AbstractA 46-year-old woman underwent upper endoscopy for evaluation of anemia, which revealed whitish granules at the duodenal papilla, diagnosed as duodenal follicular lymphoma (DFL) by biopsy. Computed tomography and abdominal ultrasonography revealed that follicular lymphoma was confined to the duodenum. Seven years after the diagnosis, fluorine-18 fluorodeoxyglucose positron emission tomography scanning revealed multiple lesions including in bone marrow and lymph nodes. Bone marrow biopsy of the right iliac bone revealed diffuse large B-cell lymphoma, indicating systemic dissemination and histologic transformation of the DFL. The patient responded to chemotherapy and has been progression-free for 2.5 years. Although DFL is usually indolent even without any treatment, systemic dissemination with histologic transformation can occur. This case suggests that the life-time follow-up that is usually done for patients with nodal follicular lymphoma should be provided to patients with DFL.


Journal of Gastroenterology and Hepatology | 2018

Multicenter study of endoscopic preoperative biliary drainage for malignant hilar biliary obstruction: E-POD hilar study: Preoperative hilar biliary drainage

Yousuke Nakai; Ryuichi Yamamoto; Masato Matsuyama; Yuji Sakai; Yukiko Takayama; Jun Ushio; Yukiko Ito; Katsuya Kitamura; Shomei Ryozawa; Tsunao Imamura; Kouhei Tsuchida; Jo Hayama; Takao Itoi; Yoshiaki Kawaguchi; Yu Yoshida; Kazuya Sugimori; Kenji Shimura; Masafumi Mizuide; Tomohisa Iwai; Ko Nishikawa; Hiroshi Yagioka; Masatsugu Nagahama; Nobuo Toda; Tomotaka Saito; Ichiro Yasuda; Kenji Hirano; Osamu Togawa; Kenji Nakamura; Iruru Maetani; Naoki Sasahira

Endoscopic nasobiliary drainage (ENBD) is often recommended in preoperative biliary drainage (PBD) for hilar malignant biliary obstruction (MBO), but endoscopic biliary stent (EBS) is also used in the clinical practice. We conducted this large‐scale multicenter study to compare ENBD and EBS in this setting.

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