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Featured researches published by Masahiko Miyata.


Cancer | 1985

Clinicopathologic study of thyroid carcinoma infiltrating the trachea

Takao Tsumori; Kazuyasu Nakao; Masahiko Miyata; Masaaki Izukura; Monden Y; Masami Sakurai; Yasunaru Kawashima; Kazuya Nakahara

Eighteen patients (10 women and 8 men), ranging in age from 37 to 80 years, with thyroid carcinoma infiltrating the trachea comprised this series. Eleven had primary and 7 had recurrent cases. Total laryngectomy was performed in 4 patients, and tracheal resection was carried out followed by end‐to‐end anastomosis in 13 patients. In one patient, reconstruction was done with Navilles artificial trachea after tracheal resection. Eleven patients were alive after 1 year and 8 months to 6 years and 7 months after the operation. This result was significantly better than that of a group of ten patients without resection of the infiltrated trachea (seven patients died within 6 months). Thus, combined resection of the upper airway improved the prognosis of advanced thyroid carcinoma with tracheal infiltration. Histologic examination of surgical specimens demonstrated well‐differentiated carcinoma in seven patients, poorly differentiated carcinoma in seven patients, undifferentiated carcinoma in three patients, and squamous cell carcinoma in one patient. The result showed a higher frequency of poorly differentiated carcinoma than in the control group of 70 patients without tracheal infiltration.


Surgery Today | 2004

Giant Adrenal Myelolipoma: Report of a Case

Hiroki Akamatsu; Masato Koseki; Hiroyuki Nakaba; Shoji Sunada; Akira Ito; Seiichi Teramoto; Masahiko Miyata

Adrenal myelolipomas are rare benign tumors composed of mature adipose tissue and hematopoietic elements that resemble bone marrow. They are usually asymptomatic, and most cases are incidentally found at radiological examination or autopsy. Symptoms such as abdominal pain and increasing girth occur only when the tumor grows large. We report the case of a giant adrenal myelolipoma in a 51-year old man who presented with a huge abdominal mass and abdominal pain. The resected tumor weighed 6 000 g and could represent the largest such tumor ever documented in the literature. We discuss the diagnosis and treatment of this unusual tumor.


World Journal of Surgery | 1995

Function of the sphincter of Oddi in patients with juxtapapillary duodenal diverticula: evaluation by intraoperative biliary manometry under a duodenal pressure load

Satoru Miyazaki; Tsuguo Sakamoto; Masahiko Miyata; Yoshio Yamasaki; Hajime Yamasaki; Keiji Kuwata

The purpose of this study was to elucidate the function of the sphincter of Oddi (SO) in patients with juxtapapillary duodenal diverticula (JDDs). The SO function was evaluated by intraoperative biliary manometry in three groups of patients. Group 1 consisted of nine patients with JDDs and a dilated common bile duct (CBD) (diameter > 10 mm). Group 2 consisted of six patients with JDDs and a normal-sized CBD (diameter < 10 mm). Group 3 consisted of 26 patients without JDDs and with normal-sized CBDs.In the absence of a duodenal pressure load, the patients in group 1 demonstrated a lower baseline SO pressure and lower resistance of the biliary outflow than patients in group 3. They also demonstrated a lower baseline SO pressure and shorter decay time (which represented terminal biliary ductal resistance) than patients in group 2. In the presence of a duodenal pressure load of 300 mm H2O, the patients in group 1 demonstrated a lower incidence of phasic SO contractions, a higher baseline SO pressure, and a higher resistance of the biliary outflow than group 2 and group 3 patients. The decay time in group 1 and group 2 patients was higher than that of group 3 patients. Based on these findings, we conclude that the SO function in patients with JDDs is impaired owing in part to long-standing compression of the terminal biliary ductal system by a distended JDD associated with a rise in intraduodenal pressure in daily life.


Transplantation | 1994

Enzyme release from mitochondria during reoxygenation of rat liver

Shigeomi Shimizu; Wataru Kamiike; Nobutaka Hatanaka; Motonobu Nishimura; Masahiko Miyata; Toru Inoue; Yukuo Yoshida; Kunio Tagawa; Hikaru Matsuda

Reoxygenation-induced release of mitochondrial aspartate aminotransferase (mAST) into the cytosol was studied using perfused rat liver. As the absolute activity of mAST in the perfusate did not indicate the degree of mitochondrial enzyme release, the following 3 methods were applied: measurement of the mAST to total AST ratio in the efferent perfusate, the digitonin infusion method, and measurement of mAST activity in the cytosolic compartment isolated from perfused livers. The results by all 3 methods were consistent and showed that mitochondrial injury occurs on reoxygenation. The mitochondrial Ca2+ content was proportional to the extent of mAST release during reoxygenation, indicating involvement of Ca2+ in the enzyme release. CsA, a potent inhibitor of Ca(2+)-induced increase in permeability of the mitochondrial membrane, completely prevented mAST release on reoxygenation. We conclude that during reoxygenation of hypoxic liver, mAST leaks into the cytosol in a Ca(2+)-dependent, CsA-sensitive manner.


The Annals of Thoracic Surgery | 1990

Acute Symptoms Due to a Huge Duplication Cyst Ruptured Into the Esophagus

Kazuya Nakahara; Yoshitaka Fujii; Shinichiro Miyoshi; Akihiro Yoneda; Masahiko Miyata; Yasunaru Kawashima

A 36-year-old housewife complained of a tight feeling in the pharynx with increasing dysphagia, dyspnea, and mild fever. Chest roentgenogram was interpreted as a cystic mass in the middle mediastinum. Computed tomography showed a cystic mass compressing the carina and the esophagus. Ten days after onset, symptoms were suddenly relieved followed by a tarry stool. The chest mass shadow decreased. Esophagofiberscopy showed two fistulas communicating with a cyst that had two chambers. Thoracotomy performed 40 days after onset showed a true duplication of the esophagus with rupture into the esophagus. This is a rare case in which it was possible to observe the sequence of events of a ruptured intramural duplication cyst by means of chest roentgenography, computed tomography, esophagofiberscopy, and cystogram.


Clinica Chimica Acta | 1989

Different patterns of leakage of cytosolic and mitochondrial enzymes

Wataru Kamiike; Masahiro Fujikawa; Masato Koseki; Junichi Sumimura; Masahiko Miyata; Yasunaru Kawashima; Hiroshi Wada; Kunio Tagawa

The mechanisms of leakage of intracellular enzymes, and especially the cytosolic and mitochondrial isozymes of aspartate aminotransferase (AST), in ischemic rat liver were studied. On recirculation of ischemic liver, cytosolic AST (cAST) promptly appeared in the blood. Release of cytosolic enzymes, including cAST and lactic dehydrogenase, resulted from disruption of blebs that protruded from parenchymal cells into the sinusoidal space. When these blebs were formed in ischemic liver, mitochondria still remained in core regions of the injured cells and were not found in the blebs. Consistent with this fact, mitochondrial AST (mAST) did not leak into the circulation from ischemic liver until most of the cAST had leaked out. This delayed leakage of mitochondrial enzymes was also consistent with the fact that the mitochondrial membranes maintained a diffusion barrier against matrix enzymes even after anoxia for 2 h, when their oxidative phosphorylation capacity had been lost. These results indicate that mitochondrial enzymes are liberated into the blood only after appreciable disintegration of the cells, probably necrosis, and that the cumulative activity of mAST in the blood should reflect the extent of necrosis in ischemic organs better than that of cAST.


Surgery Today | 1995

Concomitant coronary bypass grafting and curative surgery for cancer

Toshiki Takahashi; Susumu Nakano; Yasuhisa Shimazaki; Mitsunori Kaneko; Kazuya Nakahara; Masahiko Miyata; Wataru Kamiike; Hikaru Matsuda

The surgical management of patients with concomitant critical coronary artery disease (CAD) and surgically resectable cancer is controversial. We evaluated 19 patients who underwent concomitant coronary artery bypass grafting (CABG) and curative operation for cancer of the stomach in 9 patients, the colon in 4, the lung in 4, and the breast in 2. Each cancer operation was performed under stable hemodynamics without any serious bleeding tendency, immediately after CABG with an average of 2.5±0.8 grafts. There were no operative deaths and no incidences of perioperative myocardial infarction. Postoperative complications developed in three of the patients with lung cancer: respiratory dysfunction caused by phrenic nerve paralysis in two and mediastinitis in one. During the mean follow-up period of 33±23 months, 5 patients died of recurrent cancer or non-cardiac disease; however, all 19 patients remained free from any postoperative cardiac events and their quality of life apparently improved. This experience suggests that such simultaneous correction would be safe and beneficial in carefully selected patients who have surgically correctable CAD and potentially curable cancer.


Surgery Today | 1991

Rupture of liver metastasis of malignant melanoma —A case of hepatic resection—

Tsutomu Dousei; Masahiko Miyata; Tokio Yamaguchi; Makio Nagaoka; Eiji Takahashi; Yasunaru Kawashima

A case is reported in which resection of the left lateral segment of the liver was performed for rupture of a metastatic malignant melanoma in an attempt to control hemorrhaging. The primary lesion was located in the skin of the head, and there were multiple metastases to the lung, liver and distant nodes. The patient, a 47-year-old woman, had been undergoing systemic chemotherapy for the disseminated disease, but she presented with intraabdominal bleeding from a metastatic nodule in the left lateral segment of the liver. An emergency operation was performed, and the immediate postoperative course was uneventful. She was discharged 10 days after the operation. The patient died, however, of hemorrhagic shock due to renewed intraabdominal bleeding on the 39th postoperative day. It is concluded from the above case that hepatic resection for a bleeding metastasis of malignant melanoma is a viable option even in patients with disseminated disease.


Surgery Today | 1993

Radical resection of primary malignant melanoma of the gallbladder with multiple metastases : report of a case

Nobutaka Hatanaka; Masahiko Miyata; Wataru Kamiike; Kenzo Okumura; Tsukuru Hashimoto; Tokio Yamaguchi; Yoshinobu Kishino; Masami Sakurai; Hikaru Matsuda

We present herein an usual case of primary malignant melanoma of the gallbladder in a 51-year-old man in whom an exploratory laparotomy for melena revealed six malignant melanoma lesions located in the gallbladder, main pancreatic duct, stomach, duodenum, jejunum, and a mesenteric lymph node. Total pancreatectomy was performed and histologically, junctional activity was seen only in the gall-bladder, suggesting that this was the primary site. No melanotic lesions were found on the skin or eyes. The metastases to the main pancreatic duct and gastrointestinal tract appeared likely to have occurred as a consequence of the mucosal dissemination of the tumor cells shed into the bile. The post-operative course was uneventful and combined chemotherapy was administered for 16 months. No new metastatic lesions were found until 21 months postoperatively, when metastases were detected in the brain and thoracic spinal cord. These metastatic tumors were removed surgically, but the patient died from cerebral disturbance 26 months after the initial operation. Thus, we consider that aggressive surgical therapy was effective for extending the survival time and improving the quality of life of this patient.


European Journal of Clinical Investigation | 1977

The influence of phentolamine, an adrenergic blocking agent, on insulin secretion during surgery

Kazuyasu Nakao; Masahiko Miyata

Abstract. A rapid intravenous glucose load (20 g) was given with a phentolamine infusion during and after elective abdominal surgery. Plasma levels of glucose, free fatty acids, and insulin were measured to investigate the influence of surgical stress on insulin secretion.

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