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Featured researches published by Masahiko Miyachi.


Annals of Surgery | 2000

Management of Hilar Cholangiocarcinoma: Comparison of an American and a Japanese Experience

Jane I. Tsao; Yuji Nimura; Junichi Kamiya; Naokazu Hayakawa; Satoshi Kondo; Masato Nagino; Masahiko Miyachi; Michio Kanai; Katsuhiko Uesaka; Koji Oda; Ricardo L. Rossi; John W. Braasch; John M. Dugan

ObjectiveTo compare the experience and outcome in the management of hilar cholangiocarcinoma at one American and one Japanese medical center. Summary Background DataControversies surround the issues of extent of resection for hilar cholangiocarcinoma and whether the histopathology of such cancers are similar between patients treated in America and in Japan. MethodsRecords were reviewed of 100 patients treated between 1980 and 1995 at the Lahey Clinic in the United States, and of 155 patients treated between 1977 and 1995 at Nagoya University Hospital in Japan. Selected pathologic slides of resected cancers were exchanged between the two institutions and reviewed for diagnostic concordance. ResultsIn the Lahey cohort, there were 25 resections, 53 cases of surgical exploration with biliary bypass or intubation, and 22 cases of percutaneous transhepatic biliary drainage or endoscopic biliary drainage without surgery. In the Nagoya cohort, the respective figures were 122, 10, and 23. The overall 5-year survival rate of all patients treated (surgical and nonsurgical) during the study periods was 7% in the Lahey cohort and 16% in the Nagoya cohort. The overall 10-year survival rates were 0% and 12%, respectively. In patients who underwent resection with negative margins, the 5- and 10-year survival rates were 43% and 0% for the Lahey cohort and 25% and 18% for the Nagoya cohort. The surgical death rate for patients undergoing resection was 4% for Lahey patients and 8% for Nagoya patients. Of the patients who underwent resection, en bloc caudate lobectomy was performed in 8% of the Lahey patients and 89% of the Nagoya patients. Histopathologic examination of resected cancers showed that the Nagoya patients had a higher stage of disease than the Lahey patients. ConclusionsIn both Lahey and Nagoya patients, survival was most favorable when resection of hilar cholangiocarcinoma was accomplished with margin-negative resections. Combined bile duct and liver resection with caudate lobectomy contributed to a higher margin-negative resection rate in the Nagoya cohort.


Annals of Surgery | 1998

The pattern of infiltration at the proximal border of hilar bile duct carcinoma. A histologic analysis of 62 resected cases

Eiji Sakamoto; Yuji Nimura; Naokazu Hayakawa; Junichi Kamiya; Satoshi Kondo; Masato Nagino; Michio Kanai; Masahiko Miyachi; Katsuhiko Uesaka

OBJECTIVE To clarify the importance of different patterns of infiltration at the proximal border of hilar bile duct carcinomas. SUMMARY BACKGROUND DATA There are few detailed pathologic studies on the proximal resection margins in patients with hilar bile duct carcinoma. METHODS Serial sections of 62 specimens of resected hilar bile duct carcinoma were examined histologically to determine the involved layers and routes of invasion at the proximal border. The degree of cancer extension was determined, and the relation between the length of the tumor-free resection margin and postoperative anastomotic recurrences was analyzed. RESULTS Mucosal extension was predominant in papillary and nodular tumors, but submucosal extension was predominant in diffusely infiltrating and nodular-infiltrating tumors. Submucosal extension usually consisted of direct or lymphatic invasion. The mean length of submucosal extension was 6.0 mm. Superficial spread of cancer, defined as mucosal extension of more than 20 mm from the main lesion, was seen in 8 specimens. No patient had an anastomotic recurrence when the tumor-free resection margin was greater than 5 mm. CONCLUSIONS The pattern of infiltration at the proximal border of resected hilar bile duct carcinomas is closely related to the gross tumor type. The length of submucosal extension is usually less than 10 mm. Superficial spread of cancer is seen in more than 10% of cases. A tumor-free proximal resection margin of 5 mm appears to be adequate in hilar bile duct carcinoma.


Surgery | 1996

Preoperative intrahepatic segmental cholangitis in patients with advanced carcinoma involving the hepatic hilus.

Michio Kanai; Yuji Nimura; Junichi Kamiya; Satoshi Kondo; Masato Nagino; Masahiko Miyachi; Yasutomo Goto

BACKGROUND Major hepatic resection for biliary tract carcinoma continues to be a risky operation. In this study we examined the influence of preoperative intrahepatic segmental cholangitis on posthepatectomy mortality. METHODS We analyzed retrospectively the clinical features of 118 patients who underwent liver resection including more than two segments for biliary tract carcinoma involving the hepatic hilus. RESULTS Intrahepatic segmental cholangitis was encountered before operation in 22 cases. The morbidity and mortality rates for these patients were significantly higher than those of patients without preoperative cholangitis. Selective percutaneous transhepatic biliary drainage was performed before operation in 11 patients for segmental cholangitis. The morbidity rate of patients after hepatectomy was significantly lower than that of patients treated without percutaneous transhepatic biliary drainage. CONCLUSIONS The presence of preoperative intrahepatic segmental cholangitis is a major prognostic factor in the outcome of major hepatic resection for biliary carcinoma. Selective percutaneous transhepatic biliary drainage for preoperative intrahepatic segmental cholangitis plays an important role in reducing complications after major hepatic resection.


International Journal of Gastrointestinal Cancer | 1997

Distal Pancreatectomy with En Bloc Resection of the Celiac Artery for Carcinoma of the Body and Tail of the Pancreas

Toshihiko Mayumi; Yuji Nimura; Junichi Kamiya; Satoshi Kondo; Masato Nagino; Michio Kanai; Masahiko Miyachi; Katsura Hamaguchi; Naokazu Hayakawa

SummaryConclusionCombined resection of the celiac artery with a distal pancreatectomy (DP) increases the resectability and improves the overal prognosis of patients with locally advanced ductal cancer of the body and tail of the pancreas.BackgroundCarcinoma of the body and tail of the pancreas is often unresectable because of invasion to adjacent organs. We evaluated a DP including anen bloc resection of the celiac artery (“extended”), for pancreatic cancer that had invaded the common hepatic and/or celiac arteries.MethodsSix cases of an “extended” DP were compared with 19 cases of a “standard” DP for pancreatic ductal carcinoma in terms of clinical and pathologic findings, perioperative course, and long-term outcome. We also compared the survival rate of these two groups with a third group consisting of 22 patients with unresectable pancreatic ductal carcinoma.ResultsThe mean operative time, postoperative serum aspartate aminotransferase concentration, and length of hospital stay did not significantly differ between the “extended” and “standard” DP groups. The cumulative 1- and 3-yr accumulated survival rates for the “extended,” “standard,” and unresectable groups were 40.0, 33.3, and 5.4, and 20.0, 16.6, and 0%, respectively. Statistically significant differences (p<0.01) existed between the “extended” and unresected groups.


Journal of Cellular Biochemistry | 1997

In vitro and in vivo expression of inducible nitric oxide synthase during experimental endotoxemia: Involvement of other cytokines

Keiya Aono; Ken-ichi Isobe; Kazutoshi Kiuchi; Zou-Heng Fan; Masafumi Ito; Akihide Takeuchi; Masahiko Miyachi; Izumi Nakashima; Yuji Nimura

In this study, we investigated the expression of genes for inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF‐α), interleukin 1β (IL‐1β), interleukin 6 (IL‐6) of Kupffer cells in the presence of lipopolysaccharide (LPS), and the tissue expression of iNOS in a rat liver after LPS injection at various time intervals. The effects of L‐NG‐nitroarginine‐methyl‐esther HCI (L‐NAMF), a NO inhibitor, also were examined. The mRNA transcripts of TNF‐α IL‐1β and IL‐6 were rapidly detected no more than at 1 h after LPS stimulation, whereas the iNOS transcript was detectable from 3 h after LPS stimulation and maximally increased at 12 h. This fact suggested that these early induced cytokines were related to expression of iNOS. Using an anti‐iNOS antiserum raised against recombinant iNOS protein, immunohistochemical analysis was made to reveal kinetics of NO producing cells. The cells immunoreactive for iNOS appeared at 6 h post‐LPS injection in the sinusoids of the liver. By structural and immunohistochemical studies, almost all iNOS positive cells were identified as Kupffer cells and endothelial cells. The number of cells immunoreactive for iNOS increased until 12 h post‐LPS injection. At 24 h after LPS injection, iNOS positive cells were restricted to the foci of spotty necrosis. Hepatic injury measured by released enzymes was increased by pretreatment of L‐NAME before LPS injection. J. Cell. Biochem. 65:349–358.


Journal of Hepato-biliary-pancreatic Surgery | 1995

Preoperative management of hilar cholangiocarcinoma

Masato Nagino; Yuji Nimura; Junichi Kamiya; Satoshi Kondo; Michio Kanai; Masahiko Miyachi; Hideo Yamamoto; Naokazu Hayakawa

From both the therapeutic and diagnostic viewpoints, percutaneous transhepatic biliary drainage (PTBD) is crucial for the preoperative management of hilar cholangiocarcinoma. The direct anterior approach under fluoroscopic guidance is the most advantageous form of PTBD. Despite some advantages, endoscopic retrograde biliary drainage is contraindicated for preoperative biliary decompression. Pertinent multiple catheterizations using PTBD result in an accurate diagnosis of cancer extent, and produce effective relief of jaundice, as well as preventing the development of cholangitis. This, in turn, permits a rational surgical strategy and improved postoperative recovery. Preoperative staging of hilar cholangiocarcinoma is achieved by tube cholangiography through the PTBD catheter and by percutaneous transhepatic cholangioscopy. Angiography and percutaneous transhepatic portography are also recommended to diagneous extramural invasion of cancer. Prevention of posthepatectomy liver failure is the greatest challenge in the treatment of this disease. A multifactorial approach that combines several elements may provide sufficient data for determing the safe limits of surgery and for predicting posthepatectomy liver failure. Preoperative percutaneous transhepatic portal vein embolization (PTPE) is an effective method for preventing this intractable complication.


World Journal of Surgery | 1999

Treatment Strategy for Mucin-producing Intrahepatic Cholangiocarcinoma: Value of Percutaneous Transhepatic Biliary Drainage and Cholangioscopy

Eiji Sakamoto; Naokazu Hayakawa; Junichi Kamiya; Satoshi Kondo; Masato Nagino; Michio Kanai; Masahiko Miyachi; K. Uesaka; Yuji Nimura

Abstract. Intrahepatic cholangiocarcinomas that secrete macroscopically excessive mucin into the biliary system are rare, and few of the previously reported cases have achieved a curative resection. We defined these tumors as “mucin-producing intrahepatic cholangiocarcinomas” and clarify the optimal preoperative and surgical management for them. Eleven patients with mucin-producing intrahepatic cholangiocarcinomas underwent surgical resection in our department. The clinical, radiologic, surgical, and pathologic findings were studied. The clinical presentation of the 11 patients included repeated abdominal pain, jaundice, and fever. Conventional cholangiographies, such as percutaneous transhepatic cholangiography or endoscopic retrograde cholangiography, could not offer precise information about tumor location and extension because of abundant mucin in the biliary system. Using percutaneous transhepatic biliary drainage (PTBD) and percutaneous transhepatic cholangioscopy (PTCS), we were able to drain the mucin and determine precisely the cancer extension into intrahepatic segmental bile ducts. Based on these findings, various types of liver resection with or without extrahepatic bile duct resection were planned, and 10 patients obtained curative resection. The cumulative 5-year survival rate after curative resection was 78%. In patients with mucin-producing intrahepatic cholangiocarcinoma, PTBD and PTCS are important for evaluating the cancer extension. Rational surgery based on accurate preoperative diagnosis improved the prognosis of patients with this disease.


Journal of Hepato-biliary-pancreatic Surgery | 1997

Clinicopathological studies of mucin-producing cholangiocarcinoma

Eiji Sakamoto; Yuji Nimura; Naokazu Hayakawa; Junichi Kamiya; Satoshi Kondo; Masato Nagino; Michio Kanai; Masahiko Miyachi

Cholangiocarcinomas that produced clinically recognizable mucin (mucin-producing cholangiocarcinomas) were studied in ten patients. These ten represented 5.8% of all cholangiocarcinomas resected at our department. All tumors arose from the intrahepatic bile ducts. Macroscopically, the ten tumors were classified as: “ductectatic type” (n=3), in which papillary tumors developed in diffusely dilated intrahepatic bile ducts; “cystic type” (n=5), in which a large cystic tumor was present in the liver; and “intermediate type” (n=2), characterized by a large cystic lesion and a solid mass that infiltrated the liver parenchyma. Histologically, four tumors remained localized to the mucosal layer and six invaded the fibrous layer and the liver parenchyma. The invasion pattern of the six invasive cancers resembled that of the most common type of cholangiocarcinoma. Superficial spread of the cancer contiguous to the primary tumor was observed in four of the ten patients.


World Journal of Surgery | 1998

Manometric Findings of the Upper Esophageal Sphincter in Esophageal Achalasia

Fumihiko Yoneyama; Masahiko Miyachi; Yuji Nimura

Abstract. Pharyngeal and upper esophageal sphincter (UES) manometry was performed in 15 patients with esophageal achalasia and compared with that in 10 healthy controls. Neither the pharyngeal contraction pressure nor the UES resting pressure were significantly different between the two groups, although the UES residual pressure in patients with achalasia was significantly increased compared with that in controls. Pneumatic dilatation of the lower esophageal sphincter (LES) was performed in these patients. After successful LES dilatation, the increased UES residual pressure in patients with esophageal achalasia decreased significantly. Our results suggest that UES relaxation in patients with esophageal achalasia is incomplete compared with that in healthy adults. This UES abnormality is not a primary defect but a secondary phenomenon.


Surgery | 1995

Disseminated intravascular coagulation after liver resection: Retrospective study in patients with biliary tract carcinoma

Masato Nagino; Yuji Nimura; Naokazu Hayakawa; Junichi Kamiya; Satoshi Kondo; Masahiko Miyachi; Michio Kanal

BACKGROUND Disseminated intravascular coagulation (DIC) after hepatectomy is not well understood. The objective of this retrospective study was to evaluate hemostatic changes after extensive liver resection and to elucidate the frequency of posthepatectomy DIC. METHODS In 100 patients without cirrhosis who underwent resection of two or more segments of the liver for biliary tract carcinoma, various hemostatic parameters were measured before and after resection, and the liver function of each patient was assessed. RESULTS In patients with posthepatectomy liver failure, platelet count, fibrinogen concentrations, and prothrombin time were significantly lower than in those without such failure. Serum levels of fibrin degradation product did not differ significantly between the two groups. The minimum platelet count was significantly negatively correlated with serum total bilirubin level. Posthepatectomy DIC occurred in 2.0% of the patients. CONCLUSIONS After extensive liver resection patients exhibited a decreased platelet count with hepatic dysfunction. However, this condition rarely resulted in DIC, at least in patients without cirrhosis and serious postoperative complications.

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Yuji Nimura

Nagoya City University

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