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Featured researches published by Masaki Nara.


Transplantation Proceedings | 2000

Influence of donor condition on postoperative graft survival and function in human liver transplantation.

Eishi Totsuka; John J. Fung; Tomohiro Ishii; Atsushi Urakami; Natalia Moras; Kenichi Hakamada; Shunji Narumi; Nobukazu Watanabe; Masaki Nara; N Hashimoto; Makoto Takiguchi; T. Nozaki; Y Umehara; Mutsuo Sasaki

BODY condition of a brain death patient, such as blood electrolytes and cardiovascular system, is often unstable because of lack of homeostasis, experience of hypoxia, and multiple severe body injuries. Therefore, postoperative hepatic allograft function should be associated with general condition of cadaveric organ donor. For this reason, several retrospective analyses of donor variables have attempted to identify risk factors predictive of both patient and graft survival after liver transplantation. In the present study, we investigated influence of donor condition, including age, need for vasopressor, and serum sodium concentration, on early postoperative graft outcome in human liver transplantation by means of prospective collection of donor and recipient data.


Transplantation Proceedings | 2008

Timing for Orthotopic Liver Transplantation in Children With Biliary Atresia: A Single-Center Experience

Yoshikazu Toyoki; Kenichi Hakamada; S. Narumi; Masaki Nara; Michihiro Sugai; Hirohumi Munakata; Mutsuo Sasaki

INTRODUCTION Biliary atresia is the most common indication for orthotopic liver transplantation (OLT) in childhood. The purpose of this study was to determine predictive prognostic factors for children with biliary atresia related to the timing for OLT within 15 months after hepatoportoenterostomy (HPE). PATIENTS AND METHODS We retrospectively analyzed the medical records of 25 children (7 boys and 18 girls) who underwent HPE because of biliary atresia between January 1990 and December 2005 at our center. Data examined included age and pathologic findings at HPE, Pediatric End-Stage Liver Disease score at first admission, whether phototherapy was given, liver function test results and total bilirubin level before and 30 days after HPE, and number of cholangitis events. RESULTS Twelve children were alive with their native liver, 8 had undergone living donor OLT (all children alive), and 5 had died without OLT. Five- and 10-year survival rates without OLT after HPE were 47.4% and 26.3%, respectively. At univariate analysis, the predictive prognostic factors for children with biliary atresia were total bilirubin level at 30 days after HPE and Pediatric End-Stage Liver Disease score before HPE. At multivariate analysis, the only prognostic factor was total bilirubin level at 30 days after HPE. CONCLUSIONS In this study, the predictive prognostic factor was total bilirubin level at 30 days after HPE. Orthotopic liver transplantation within 15 months after HPE is needed in children with biliary atresia with a high total bilirubin level at 30 days after HPE.


Transplantation | 2001

Efficacy of double filtration plasmapheretic cross-circulation using a high permeability membrane between totally hepatectomized dogs and donor pigs.

Masaki Nara; Kenichi Hakamada; Eishi Totsuka; Tsuyoshi Nozaki; Makoto Takiguchi; Mutsuo Sasaki

BACKGROUND Major obstacles to develop a bioartificial liver are xenogeneic immune reactions and viral infection from donor pigs. To solve these problems, we studied the effect of xenogeneic double filtration plasmapheretic cross-circulation (DFPCC) using a high performance semipermeable membrane on totally hepatectomized dogs. METHODS Mongrel dogs, weighing 12-15 kg, underwent total hepatectomy in one stage (n=18). One hr after total hepatectomy, the femoral vein and the jugular vein were cannulated in both dogs and pigs by using the blood access catheter tubes that were connected to the DFPCC system. In the DFPCC circuit, filtrated dog plasma and pig plasma counterflowed in a hollow fiber cartilage at a rate of 25 ml/min for 6 hr and met through a semipermeable membrane with 100 kd nominal molecular weight cut-off (n=5). In control dogs, the circuit was not connected to the pig (n=13). RESULTS In vitro mass transfer study suggested that very little immunoglobulins crossed the semipermeable membrane. During and after 6 hr of DFPCC, anhepatic dogs had significantly lower blood ammonia and aromatic amino acid levels than did controls. DFPCC-treated dogs demonstrated decreased intracranial pressure and survived significantly longer than control dogs (20.75+/-3.80 hr vs. 14.75+/-1.30 hr, P<0.05). Histology showed no xenogeneic rejection in both dogs and pigs. CONCLUSIONS Our DFPCC systems with a high permeability membrane demonstrated detoxification-function and contributed to intracranial decompression and longer animal survivals without adverse immune reaction and the possibility of zoonosis.


Transplantation Proceedings | 2008

Living donor liver transplantation for a child with recurrent pediatric adult-type hepatocellular carcinoma.

Masaki Nara; Yoshikazu Toyoki; Kenichi Hakamada; S. Narumi; Keinosuke Ishido; Michihiro Sugai; Hirohumi Munakata; Etsuro Ito; Mutsuo Sasaki

INTRODUCTION Pediatric hepatocellular carcinoma (HCC) is an uncommon disease with a poor prognosis. There are few reports about liver transplantation for pediatric adult-type HCC. We experienced a case of living donor liver transplantation (LDLT) for a child with recurrent pediatric adult-type HCC. CASE REPORT A 12-year-old boy was admitted to the Department of Pediatrics in our institution due to HCC in May 2005. He underwent hepatectomy after 3 courses of chemotherapy in July 2005. After the operation, he had 2 more courses of the same chemotherapy. His posttheraputic course was uneventful for 1 year. However, his alpha-fetoprotein level increased and a computed tomography (CT) scan showed recurrent tumor in his remnant liver in October 2006. He underwent another chemotherapy session immediately. However, CT revealed multiple liver tumors after chemotherapy in December 2006. His mother requested to be an LDLT donor, which was performed on January 23, 2007. The donor operation was a right hepatic lobectomy. The postoperative course of the donor was unremarkable and she has now returned to work. The recipients posttransplantation course was uneventful and he was discharged at postoperative day 53 and is currently doing well. CONCLUSION Liver transplantation in conjunction with chemotherapy may have an increasing role in the management of pediatric HCC.


Liver Transplantation | 2008

Biliary hemorrhage after removal of an expandable metallic stent during liver transplantation

Shunji Narumi; Kenichi Hakamda; Yoshikazu Toyoki; Keinosuke Ishido; Masaki Nara; Syuichi Yoshihara; Mutsuo Sasaki

The self‐expandable metallic stent (SEMS) has become a common device for palliative treatment of malignant biliary obstructions or benign strictures. Despite the ease of placement of SEMSs, their removal has been reported to be very difficult. Here, we report a case with primary sclerosing cholangitis who developed massive hemorrhage after intraoperative removal of a SEMS. Possible living donor liver transplantation (LT) was considered for a 49‐year‐old female with primary sclerosing cholangitis. However, her general condition did not meet the criteria for LT; therefore, she was referred back to her primary physician. Two years later, she developed jaundice, and her primary physician placed multiple SEMSs, 1 of which was placed across the papilla of Vater. She was evaluated rapidly, and underwent living donor LT. During the operation, the common bile duct was examined and an incision was made. A stent was found firmly embedded in the bile duct. Each wire of the SEMS was pinched and then successfully pulled out 1 by 1. Finally, all parts of the SEMS were removed. Before creating the Roux‐en‐Y limb, hemorrhage from the remnant bile duct was confirmed by examination of the duodenum and bile duct stump. The bile duct was sewn internally with monofilament stitches and compressed for 10 minutes. Finally, hemostasis was brought about and transplantation was completed successfully. Despite some reports regarding successful endoscopic removal of SEMSs, its removal in patients with portal hypertension coagulopathy is risky. SEMSs should not be placed in patients who are candidates for LT. Liver Transpl 14:1578–1581, 2008.


World Journal of Gastroenterology | 2008

Hemosuccus pancreaticus: Problems and pitfalls in diagnosis and treatment

Yoshikazu Toyoki; Kenichi Hakamada; Shunji Narumi; Masaki Nara; Keinosuke Ishido; Mutsuo Sasaki


World Journal of Gastroenterology | 2008

Des-gamma-carboxy prothrombin as an important prognostic indicator in patients with small hepatocellular carcinoma

Kenichi Hakamada; Norihisa Kimura; Takuya Miura; Hajime Morohashi; Keinosuke Ishido; Masaki Nara; Yoshikazu Toyoki; Shunji Narumi; Mutsuo Sasaki


World Journal of Gastroenterology | 2008

Anaplastic carcinoma associated with a mucinous cystic neoplasm of the pancreas during pregnancy: Report of a case and a review of the literature

Kenichi Hakamada; Takuya Miura; Kimura A; Masaki Nara; Yoshikazu Toyoki; Shunij Narumi; Mutsuo Sasak


World Journal of Gastroenterology | 2008

A case of invasive hemolymphangioma of the pancreas

Yoshikazu Toyoki; Kenichi Hakamada; Shunji Narumi; Masaki Nara; Daisuke Kudoh; Keinosuke Ishido; Mutsuo Sasaki


World Journal of Gastroenterology | 2008

An easier method for performing a pancreaticojejunostomy for the soft pancreas using a fast-absorbable suture.

Kenichi Hakamada; Shunji Narumi; Yoshikazu Toyoki; Masaki Nara; Kenosuke Ishido; Takuya Miura; Norihito Kubo; Mutsuo Sasaki

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H. Ono

Hirosaki University

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