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Dive into the research topics where Toshihisa Tamura is active.

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Featured researches published by Toshihisa Tamura.


Hpb | 2014

Risk factors for a prolonged operative time in a single-incision laparoscopic cholecystectomy

Norihiro Sato; Kei Yabuki; Kazunori Shibao; Yasuhisa Mori; Toshihisa Tamura; Aiichiro Higure; Koji Yamaguchi

BACKGROUND A prolonged operative time is associated with adverse post-operative outcomes in laparoscopic surgery. Although a single-incision laparoscopic cholecystectomy (SILC) requires a longer operative time as compared with a conventional laparoscopic cholecystectomy, risk factors for a prolonged operative time in SILC remain unknown. METHODS A total of 20 clinical variables were retrospectively reviewed to identify factors for a prolonged operative time (longer than 3 h) in a total of 220 consecutive patients undergoing SILC. RESULTS The median operative time was 145 min (range, 55-435) and a prolonged operative time was required in 62 patients (28%). Independent factors that predict a prolonged operative time as identified through multivariate analysis were body mass index (BMI) (P = 0.009), acute cholecystitis (P < 0.001) and operator (resident or staff surgeon) (P < 0.001). Furthermore, a prolonged operative time was significantly associated with an increased amount of intra-operative blood loss (P < 0.001) and a prolonged stay after surgery (P < 0.001). CONCLUSIONS These findings suggest that a higher BMI, acute cholecystitis and a resident as an operator significantly increase the duration of SILC procedures.


Case Reports in Gastroenterology | 2010

Lymphoepithelioma-Like Carcinoma of the Stomach with Epithelioid Granulomas.

Toshihisa Tamura; Tetsuo Hamada; Tatsuhiko Sako; Kosuke Makihara; Kozue Yamada; Kenji Kashima; Shigeo Yokoyama; Keiji Hirata; Yasutaka Hachiya; Tokihiko Fukuyama; Yutaka Hirano

An 83-year-old Japanese man was admitted to our hospital for gastric adenocarcinoma mimicking a submucosal tumor in the gastric body. Considering his general condition, partial resection of the stomach and dissection of regional lymph nodes were performed; a dome-shaped tumor that was largely covered by normal mucosa and having a shallow central stellate ulcer was removed. Histopathologically, the carcinoma cell nests were surrounded by prominent lymphoid stroma. Sarcoid-like epithelioid granulomas were noted both in the tumor stroma and in the regional lymph node with metastasis. Epstein-Barr virus (EBV)-encoded RNA (EBER) in situ hybridization showed an intense and diffuse positive reaction in the carcinoma cells and no reaction in the surrounding gastric and lymphoid tissues. While the presence of lymphoid stroma is a characteristic finding in EBV-associated lymphoepithelioma-like carcinoma, sarcoid-like epithelioid granulomas might be associated with latent EBV infection.


World Journal of Gastroenterology | 2013

Stapled gastro/duodenojejunostomy shortens reconstruction time during pylorus-preserving pancreaticoduodenectomy

Norihiro Sato; Kei Yabuki; Shiro Kohi; Yasuhisa Mori; Noritaka Minagawa; Toshihisa Tamura; Aiichiro Higure; Koji Yamaguchi

AIM To investigate whether a stapled technique is superior to the conventional hand-sewn technique for gastro/duodenojejunostomy during pylorus-preserving pancreaticoduodenectomy (PpPD). METHODS In October 2010, we introduced a mechanical anastomotic technique of gastro- or duodenojejunostomy using staplers during PpPD. We compared clinical outcomes between 19 patients who underwent PpPD with a stapled gastro/duodenojejunostomy (stapled anastomosis group) and 19 patients who underwent PpPD with a conventional hand-sewn duodenojejunostomy (hand-sewn anastomosis group). RESULTS The time required for reconstruction was significantly shorter in the stapled anastomosis group than in the hand-sewn anastomosis group (186.0 ± 29.4 min vs 219.7 ± 50.0 min, P = 0.02). In addition, intraoperative blood loss was significantly less (391.0 ± 212.0 mL vs 647.1 ± 482.1 mL, P = 0.03) and the time to oral intake was significantly shorter (5.4 ± 1.7 d vs 11.3 ± 7.9 d, P = 0.002) in the stapled anastomosis group than in the hand-sewn anastomosis group. There were no differences in the incidences of delayed gastric emptying and other postoperative complications between the groups. CONCLUSION These results suggest that stapled gastro/duodenojejunostomy shortens reconstruction time during PpPD without affecting the incidence of delayed gastric emptying.


Journal of the Pancreas | 2014

Pancreatic Somatostatinoma Diagnosed Preoperatively: Report of a Case

Yasuhisa Mori; Norihiro Sato; Ryuta Taniguchi; Toshihisa Tamura; Noritaka Minagawa; Kazunori Shibao; Aiichiro Higure; Mitsuhiro Nakamoto; Masashi Taguchi; Koji Yamaguchi

CONTEXT Somatostatinoma is a rare neoplasm of the pancreas. Preoperative diagnosis is often difficult. CASE REPORT We report a 72-year-old woman with a pancreatic head tumor measuring 37 mm in diameter, and enlargement of the lymph nodes on the anterior surface of the pancreatic head and the posterior surface of the horizontal part of the duodenum. Laboratory data showed an elevated plasma somatostatin concentration. Examination of a biopsy specimen of the pancreatic head mass obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) showed histopathological features of a neuroendocrine tumor. Immunohistochemical staining showed that the tumor cells were positive for somatostatin, leading to a preoperative diagnosis of pancreatic somatostatinoma. The patient underwent pylorus-preserving pancreaticoduodenectomy. The plasma somatostatin concentration decreased progressively after surgery. CONCLUSIONS A rare case of pancreatic somatostatinoma with lymph node metastases was presented. Immunohistochemical analysis of a biopsy specimen obtained by EUS-FNA was useful for preoperative diagnosis.


Pancreas | 2013

Sarcoidosis in a patient with a circumportal pancreas with a retroportal main pancreatic duct: a case report.

Koji Yamaguchi; Norihiro Sato; Noritaka Minagawa; Masaru Matsumura; Yasuhisa Mori; Toshihisa Tamura; Kazunori Shibao; Aiichiro Higure

juvant chemotherapy with gemcitabine for the patients who underwent distal pancreatectomy for pancreatic body and/or tail cancer is currently the standard treatment. Furthermore, thrombocytopenia induced by gemcitabine is one of the common adverse events. Therefore, thrombocytosis during adjuvant chemotherapy with gemcitabine even after distal pancreatectomy is rare. Moreover, in a large series, 10% of the patients with unresectable advanced pancreatic cancer treated with gemcitabine with erlotinib developed grade 3/4 thrombocytopenia, and erlotinib did not affect platelet count during chemotherapy with gemcitabine. To our knowledge, although many reports showed thrombocytopenia induced by gemcitabine with or without erlotinib, no reports showed thrombocytosis induced by the combination of gemcitabine with erlotinib. In the 2 cases reported herein, the molecular biological mechanism by which administration of erlotinib induces thrombocytosis after splenectomy remains unclear. However, postsplenectomy use of erlotinib could be a risk factor for severe thrombocytopenia during chemotherapy in patients with pancreatic cancer.


Hepatobiliary surgery and nutrition | 2016

Preoperative body mass index-to-prognostic nutritional index ratio predicts pancreatic fistula after pancreaticoduodenectomy

Norihiro Sato; Toshihisa Tamura; Noritaka Minagawa; Keiji Hirata

BACKGROUND Estimating or scoring the risk of post-operative pancreatic fistula (POPF) may help with selection of high-risk patients and individualized patient consent. However, there are no simple and reliable preoperative predictors of POPF used in daily clinical practice. METHODS We investigated the utility of body mass index-to-prognostic nutritional index (BMI/PNI) ratio as a preoperative marker to predict the development of POPF in 87 patients undergoing pancreaticoduodenectomy. RESULTS The overall incidence of clinical (grade B/C) POPF was 17% (15 of 87 patients). Among various pre-, intra-, and post-operative variables analyzed, higher BMI and lower PNI were identified as independent predictors for POPF by multivariate analysis. We therefore investigated BMI/PNI ratio as a preoperative predictor for POPF. BMI/PNI ratio was significantly higher in patients with POPF than in those without POPF (0.54 vs. 0.45, P=0.0007). A receiver operating characteristic (ROC) curve analysis demonstrated a fair capability of BMI/PNI ratio to predict the occurrence of POPF (area under the ROC curve 0.781). With a cut-off value of 0.5, the sensitivity, specificity, and diagnostic accuracy of BMI/PNI ratio to predict POPF was 73%, 74%, and 74%, respectively. In particular, when restricted to a subgroup of elderly (≥75 years old) male patients, the sensitivity, specificity, and diagnostic accuracy of BMI/PNI ratio was 100%, 100%, and 100%, respectively. CONCLUSIONS The BMI/PNI ratio is a simple preoperative marker to predict the occurrence of POPF after pancreaticoduodenectomy.


International Journal of Surgery | 2015

Single-incision laparoscopic cholecystectomy for acute cholecystitis: A retrospective cohort study of 52 consecutive patients

Norihiro Sato; Shiro Kohi; Toshihisa Tamura; Noritaka Minagawa; Kazunori Shibao; Aiichiro Higure

BACKGROUND Single-incision laparoscopic cholecystectomy (SILC) has become increasingly popular but its role in acute cholecystitis remains controversial. METHODS We compared the clinical features and outcomes of SILC procedures between 52 patients with acute cholecystitis (the AC group) and 308 patients without acute cholecystitis (the NAC group). We also analyzed clinical variables to identify factors affecting difficulties associated with SILC for acute cholecystitis. RESULTS The patients in the AC group were significantly older than those in the NAC group (72 vs. 61 years, median, P = 0.0005). The preoperative levels of white blood cell counts were significantly higher in the AC group than in the NAC group (6600 vs. 5500/μL, P = 0.0004). The operative time was significantly longer in the AC group than in the NAC group (188 vs. 135 min, P < 0.0001). The volume of intraoperative blood loss was significantly larger in the AC group than in the NAC group (20 vs. 5 mL, P < 0.001). Furthermore, additional trocar insertion was required in 12% in the NAC group, whereas it was required in 60% in the AC group (P < 0.0001). Regarding the difficulties of SILC for acute cholecystitis, delayed operation (after 72 h from the onset) was significantly associated with a prolonged operative time, while a higher grade of acute cholecystitis (grade II or III) was significantly associated with an increased blood loss during surgery. CONCLUSIONS These findings suggest that when compared to SILC for gallbladder diseases without acute inflammation, SILC for acute cholecystitis was associated with a longer operative time, increased blood loss, higher rate of additional trocar requirement, higher rate of postoperative complications, and longer hospital stay. The difficulties associated with SILC for acute cholecystitis were affected by the timing of surgery and the grade of inflammation.


World Journal of Gastroenterology | 2014

Rare combination of familial adenomatous polyposis and gallbladder polyps

Yasuhisa Mori; Norihiro Sato; Nobutaka Matayoshi; Toshihisa Tamura; Noritaka Minagawa; Kazunori Shibao; Aiichiro Higure; Mitsuhiro Nakamoto; Masashi Taguchi; Koji Yamaguchi

Familial adenomatous polyposis is associated with a high incidence of malignancies in the upper gastrointestinal tract (particularly ampullary adenocarcinomas). However, few reports have described a correlation between familial adenomatous polyposis and gallbladder neoplasms. We present a case of a 60-year-old woman with familial adenomatous polyposis who presented with an elevated mass in the neck of the gallbladder (measuring 16 mm × 8 mm in diameter) and multiple small cholecystic polyps. She had undergone a total colectomy for ascending colon cancer associated with familial adenomatous polyposis 22 years previously. The patient underwent laparoscopic cholecystectomy under a preoperative diagnosis of multifocal gallbladder polyps. Pathologic examination of the resected gallbladder revealed more than 70 adenomatous lesions, a feature consistent with adenoma of the gallbladder. This case suggests a requirement for long-term surveillance of the biliary system in addition to the gastrointestinal tract in patients with familial adenomatous polyposis.


Journal of UOEH | 2017

A Case of Retroperitoneal Paraganglioma

Takao Amaike; Toshihisa Tamura; Atsuhiro Koga; Kazunori Shibao; Aiichiro Higure; Keiji Hirata

We report a surgical case of retroperitoneal paraganglioma. A paraganglioma is a catecholamine-producing tumor originating in the chromaffin cells of the sympathetic ganglion. It is a kind of pheochromocytoma which occurs on the outside of the adrenal gland. The patient was a 72 year old male with a history of hypertension and a pacemaker implantation. A mass in the ventral side of the right iliopsoas muscle was detected during a routine contrasting computed tomography (CT) examination for checking his pacemaker. The mass was considered to be malignant, and a laparotomy and mass enucleation was performed. It was diagnosed as phaeochromocytoma, based on the pathology and immunestology of the excised specimen. The hypertension was cured soon after the surgery. Nine months after surgery, there is no evidence of any abnormality or recurrence. There is a previous report of a recurrence 25 years after surgery, so a careful follow-up of this patient will be necessary in the future.


Journal of UOEH | 2017

A Review of 7 Cases of Laparoscopic Cholecystectomy for Pediatric Cholecystolithiasis

Nobutaka Matayoshi; Norihiro Sato; Takashi Okimoto; Takehide Tajima; Koichi Arase; Nagahiro Sato; Toshihisa Tamura; Kazunori Shibao; Aiichiro Higure; Keiji Hirata

Pediatric cholecystolithiasis is a relatively rare disease, but it is recently increasing in Japan. Laparoscopic cholecystectomy (LC) is a standard procedure for cholecystolithiasis not only in adults but also in children, and we are aggressively introducing single-incision laparoscopic cholecystectomy (SILC) at our hospital. We reviewed the patient characteristics, operation procedures and outcomes of 7 children (15 years old and under) with cholecystolithiasis who underwent LC in our hospital between August 1995 and December 2015. The 7 patients included 5 males and 2 females, with a mean age of 8 years 6 months. Underlying diseases were found in 5 patients (cerebral palsy in 2 patients, pancreaticobiliary maljunction with common bile duct stones in 1, acute lymphocytic leukemia in 1, hereditary stomatocytosis in 1), and none were found in the other 2. LC (3 conventional LC and 2 SILC) was performed in 5 of the patients. Laparoscopic choledocholithotomy was performed in 1 patient and laparoscopic splenectomy (LS) was performed in 1 patient at the same time. The mean operative time in all the cases of LC was 108 (70-140) minutes (conventional LC 113 (70-140) min, SILC 100 (90-100) min). Intraoperative cholangiography was performed in 4 cases and omitted in 3 cases. The only postoperative complication was a wound infection in 1 patient. The umbilical skin incision length in the SILC was 2.0 cm. We conclude that LC can be safely performed for children with cholecsytolithiasis, and that SILC is feasible and advantageous in terms of its improved cosmesis.

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Aiichiro Higure

Primate Research Institute

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Norihiro Sato

Johns Hopkins University

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Keiji Hirata

University of Occupational and Environmental Health Japan

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Kohji Okamoto

University of Occupational and Environmental Health Japan

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Shiro Kohi

University of Occupational and Environmental Health Japan

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Kei Yabuki

University of Occupational and Environmental Health Japan

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