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Featured researches published by Shungo Hiroyasu.


Gastrointestinal Endoscopy | 1999

Successful management of ruptured duodenal varices by means of endoscopic variceal ligation: report of a case.

Masayuki Shiraishi; Shungo Hiroyasu; Takao Higa; Satoko Oshiro; Yoshihiro Muto

Less-invasive therapies such as endoscopic injection sclerotherapy and endoscopic variceal ligation are being used increasingly in the management of gastroesophageal varices caused by portal hypertension.1 Balloon-occluded retrograde transvenous obliteration recently has been developed mainly for management of gastric fundal varices.2 However, no definitive conservative therapy for duodenal varices has been established, and surgical intervention still is used in emergency situations because of the lack of alternatives.3,4 Unsuccessful management of ruptured duodenal varices may result in death.5 We herein report the first known case of a ruptured duodenal varix successfully managed with endoscopic variceal ligation.


Digestive Surgery | 1999

Radiation-Associated Rectal Cancer: Report of Four Cases

Osamu Tamai; Eiji Nozato; Hiroshi Miyazato; Tsutomu Isa; Shungo Hiroyasu; Masayuki Shiraishi; Toshiomi Kusano; Yoshihiro Muto; Masahiro Higashi

Background/Aims: Radiation-associated rectal cancer is a remarkable clinical entity. We demonstrate 4 patients (mean age 68 years, range 63–74) who had undergone pelvic radiotherapy for cervical cancer. We indicate some characteristics of radiation-associated rectal cancer. Results: Two patients had received intracavitary and external pelvic radiotherapy, while the remaining 2 had external pelvic radiotherapy following hysterectomy. The mean total radiation dose was 63 Gy, though radiation dose information was not available for 1 patient. Colorectal cancer developed at a mean time of 20.7 years (range 11–30) after radiation therapy. All patients presented with chronic radiation colitis, and 3 demonstrated abnormal tumor markers. Colonoscopy revealed an ulcerative, localized well-differentiated adenocarcinoma of the rectosigmoid colon in 1 patient, and diffusely infiltrating cancers of the lower rectum, one signet-ring cell carcinoma and two mucinous carcinomas in the remaining 3. One case was stage I, 2 were stage IIIa, and the remaining case was stage IV. Three patients underwent abdominoperineal resection. The remaining patient was felt to be inoperable. The colorectal wall demonstrated the changes of chronic radiation injury. Two patients died within a short time because of their advanced cancers. Conclusion: Radiation-associated rectal cancer has a tendency to be diagnosed in the advanced stage and to have a poor prognosis. A literature review and our case report suggest that since there are no reliable clinical or laboratory indicators of the presence of a curable colorectal cancer in the setting of chronic radiation proctocolitis, surveillance with a colonoscope should be done 10 years after irradiation in patients with previous pelvic radiotherapy.


World Journal of Surgery | 1998

Radiation Enterocolitis: Overview of the Past 15 Years

Masayuki Shiraishi; Shungo Hiroyasu; Tomonari Ishimine; Masamori Shimabuku; Toshiomi Kusano; Masahiro Higashi; Yoshihiro Muto

AbstractFrom April 1980 to April 1995 a total of 54 patients (53 women, 1 man) were hospitalized in our department for the surgical treatment of radiation enterocolitis. Two surgical protocols were applied for these patients: intestinal decompression procedures alone (intestinal bypass, colostomy, or both; n= 18) or an intestinal resection in addition to decompression (n= 36). The clinical factors contributing to survival after irradiation were retrospectively reviewed by a multiple variate proportional hazards model. As a result, patients treated with decompression procedures alone had an 11 times higher risk for death than those treated with the addition of intestinal resection. In the former group, 5 of 18 patients died of bleeding from the remaining intestine after operation. We concluded that surgical resection of the diseased intestine is a useful procedure for treating radiation enterocolitis to reduce intestinal bleeding from the irradiated intestine.


World Journal of Surgery | 1999

Characteristics of Hepatocellular Carcinoma in Patients with Negative Virus Markers: Clinicopathologic Study of Resected Tumors

Masayuki Shiraishi; Shungo Hiroyasu; Masayoshi Nagahama; Syuji Tomita; Takumi Miyahira; Toshiomi Kusano; Masato Furukawa; Yoshihiro Muto

n= 11), hepatitis C virus antibody positive (HC, n= 21), and non-BC (both HbsAg and HCVAb negative, n= 12). Seven patients were excluded from the study because of operative death (n= 3), a history of alcohol abuse (n= 3), or the presence of dual positive HB and HC virus markers (n= 1). The data were analyzed by either an analysis of variance (ANOVA) or a contingency table. The age of the non-BC patients was higher (63.0 ± 4.1, ± SE) than that of HB patients (54.0 ± 3.2, p < 0.05) but was identical to that of the HC group (62.0 ± 1.8). Among the preoperative laboratory data, the serum glutamic oxaloacetate and glutamate pyruvate transaminoses (GOT, GPT) levels were statistically lower in the non-BC patients (32.8 ± 4.8 and 28.0 ± 4.4 IU/L, respectively) than in the HB and HC patients. The pathologic features of the resected specimens in the non-BC patients showed more invasive growth than in specimens from the HB or HC patients. The clinical stages (defined based on the criteria of the Japanese Association of Hepatocellular Carcinoma) were also more advanced in the non-BC patients than in the other groups. Postoperative survival time showed no significant difference among the groups. In conclusion, the non-BC patients had comparatively greater invasive growth and more advanced clinical stages than the HB and HC patients, despite the absence of liver cirrhosis, and so demonstrated the same poor survival data as observed in the HB and HC patients.


World Journal of Surgery | 1998

Perforation Due to Metastatic Tumors of the Ileocecal Region

Masayuki Shiraishi; Shungo Hiroyasu; Eiji Nosato; Hideaki Shimoji; Toshiomi Kusano; Yoshihiro Muto

Abstract. We reviewed our department’s medical records between April 1986 and April 1994 to identify patients who showed acute abdominal symptoms requiring surgical treatment due to metastatic tumors of the small intestine. In group A, seven patients (30%) were treated for acute peritonitis, and all were found to have an intestinal perforation due to hematogenous metastases (group A). In group B, 16 patients (70%) were treated for an intestinal obstruction, and all were found to have disseminated tumors of the small intestine (group B). In group A all tumors were isolated and located exclusively in the ileocecal region, whereas all tumors in group B showed peritoneal dissemination, with no predominant anatomic localization. In general, the intestinal tumors in group A originated from cancers of the upper aerodigestive tract, whereas those in group B originated from advanced cancers in the abdominal cavity. The tumors were significantly smaller and the period between the onset of symptoms from the original malignancy and the onset of abdominal symptoms (perforation or obstruction) was significantly shorter in group A. In conclusion, intestinal metastases located in the ileocecal region have unique clinicopathologic features and so should be recognized as a distinct disease entity. Therefore when patients with a known upper aerodigestive malignancy exhibit acute abdominal symptoms, intestinal metastasis to the ileocecal region, necrotic changes, and perforation should be considered in the differential diagnosis.


European Surgical Research | 2001

Role of the Fas System in Liver Regeneration after a Partial Hepatectomy in Rats

Kaoru Taira; Shungo Hiroyasu; Masayuki Shiraishi; Yoshihiro Muto; Takehiko Koji

Apoptosis is involved in the homeostatic control of organs. The aim of this study was to define the in vivo role of apoptosis-related proteins including the Fas system and Bcl-2 in liver regeneration following a partial hepatectomy (PH). We used 70% hepatectomized rats which were serially sacrificed from 12 h to 28 days. The expressions of Fas, Fas ligand, and Bcl-2 were examined by semiquantitative RT-PCR and immunohistochemistry. Liver regeneration, as examined by PCNA staining, peaked from 24 h to day 3, and declined from day 5. On the other hand, hepatocyte apoptosis, as examined by TUNEL staining, was seldom observed until 24 h, but increased from 1 week after PH. In the RT-PCR study, Fas showed an early decline by 24 h, followed by a later peak from days 3 to 5, and then a constant expression thereafter. Meanwhile, the Fas ligand was also low until day 3, but showed a remarkable increase from days 5 to 7, followed by a gradual decrease. On the other hand, Bcl-2 showed an early peak until 24 h, followed by a decline from day 5. In an immunohistochemical study, the time courses of these protein expressions were almost synchronous with their mRNAs in the RT-PCR study. We thus conclude that the coordinated interplay between these apoptosis-related proteins and hepatocyte apoptosis suggests the possible involvement of these proteins in the course of liver regeneration.


Surgery Today | 1996

Adenovirus-Mediated Gene Transfer Using Ex Vivo Perfusion of the Heart Graft

Masayuki Shiraishi; Toshiomi Kusano; Junji Hara; Shungo Hiroyasu; Ma Shao-ping; Yoshihiro Makino; Yoshihiro Muto

A replication-deficient adenovirus was used for ex vivo gene transfer into rat heart grafts under conditions simulating clinical transplantation. The adenoviral vector, AdHCMVsp1LacZ, containing an expression cassette of Escherichiae coli lacZ, was used to perfuse heart grafts during cold ischemia before transplantation. Heart grafts were perfused with University of Wisconsin (UW) solution containing either 0 pfu, 5×1010 pfu, or 1×1011 pfu of viral vector, and were preserved for either 2 or 4 h and then transplanted into syngeneic recipients. The animals were killed at 1, 7, and 14 days after transplantation. The infection rate was assessed by histochemical staining for β-galactosidase. Using polymerase chain reaction (PCR), viral DNA presence was confirmed in every graft perfused with viral vectors. The protein production from the transfected gene was confirmed by a functional protein assay. An efficient gene transfer was achieved with an infection rate of 1%–1.5% for all cardiac myocytes, as assessed by 5-bromo-4-chloro-indolyl-β-d-galactopyranoside (X-gal) staining. All studies were negative in the control grafts. Gene expression persisted for at least 10 days after transplantation. We thus conclude that an efficient adenovirus-mediated gene transfection and expression of gene products can be achieved in ex vivo perfusion of the heart graft during cold preservation.


Transplantation | 1999

Analysis Of Fas System In Pulmonary Injury Of Graft-versus-host Disease After Rat Intestinal Transplantation

Shungo Hiroyasu; Masayuki Shiraishi; Takehiko Koji; Toure Mamadi; Hideki Sugawa; Hirofumi Tomori; Yoshihiro Muto

The lung is one of the primary targets of acute graft-versus-host disease (GVHD), which is the principal complication that occurs after allogeneic intestinal transplantation. The purpose of this study is to investigate the involvement of Fas/Fas ligand system in pulmonary injury after rat semi-allogeneic intestinal transplantation. The lungs were serially harvested from LEW x BN F1(LBNF1) recipients of either LEW heterotopic intestinal allografts or LBNF1 isografts, on days 1, 3, 5, 9, and 13 posttransplant. In light microscopy, pulmonary injury became apparent on day 13 in the allogeneic combination, showing a thickening of the alveolar septa. The incidence of apoptosis, examined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) biotin nick end-labeling, was observed to increase steadily in the alveolar cells accompanied by a progression of GVHD. In an immunohistochemical study, Fas was constitutively expressed in the lung, although Fas ligand was expressed most extensively on day 9. The immunoreactivity of both Fas and Fas ligand were observed in alveolar cells, in addition to leukocytes. An analysis by reverse transcription polymerase chain reaction also revealed that the expression of Fas mRNA was constitutive without any significant change, although that of Fas ligand mRNA increased substantially and peaked on day 9, which was significant compared to the isogeneic combination. In conclusion, transcriptionally up-regulated Fas ligand and increased number of apoptosis suggests that the Fas system may play a role in the pathophysiology of GVHD-induced pulmonary injury.


Surgical Laparoscopy Endoscopy & Percutaneous Techniques | 2000

Combined endoscopic and surgical treatment for multiple polyps of the small intestine in Peutz-Jeghers syndrome: a case report.

Kaoru Taira; Hirotaka Matsubara; Tsutomu Isa; Hiroshi Miyazato; Shungo Hiroyasu; Masayuki Shiraishi; Yoshihiro Muto; Fukunori Kinjo

Combined endoscopic and surgical treatment in a 14-year-old girl with Peutz-Jeghers syndrome is reported herein. The patient was diagnosed with Peutz-Jeghers syndrome because of mucocutaneous pigmentation and hamartomas of the small intestine at 10 years of age, when she underwent an emergency laparotomy for an intussusception of the small intestine. Since this diagnosis, she has undergone follow-up, and barium radiologic and endoscopic studies have shown multiple polyps of various sizes from the stomach throughout the small intestine and to the colon. This time, with the use of combined endoscopic and surgical treatment for polyps of the small intestine, 26 polyps were removed endoscopically by performing only one enterotomy. This combined technique may allow for a longer interval between laparotomies, therefore reducing the complications associated with multiple laparotomies and resections.


Journal of Gastroenterology | 1999

Common bile duct blood clot: an unusual cause of ductal filling defects for calculi.

Hideaki Shimoji; Masayuki Shiraishi; Shungo Hiroyasu; Tsutomu Isa; Toshiomi Kusano; Yoshihiro Muto

Abstract: We report a case of obstructive jaundice caused by a blood clot in the common bile duct in a 75-year-old man with cirrhosis. Five years prior to his admission, he had undergone a left hepatectomy for hepatocellular carcinoma. At the present admission, he appeared icteric, and endoscopic retrograde cholangiography revealed filling defects in the common bile duct. Choledochotomy was therefore performed for possible common duct stones, and exploration of the duct showed blood clot casts filling the duct. The casts were easily removed, and the patients postoperative course was uneventful. However, he developed ascites and jaundice 1 month later and died of liver failure approximately 3 months after undergoing the choledochotomy. Autopsy revealed hemorrhagic necrosis in the proximal intrahepatic duct of the posterior segment, which was considered to be the cause of the observed hemobilia, as well as the blood clot in the common bile duct at surgery. We report this rare case and discuss the cause of hemobilia.

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Yoshihiro Muto

University of the Ryukyus

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Toshiomi Kusano

University of the Ryukyus

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Hirofumi Tomori

University of the Ryukyus

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Kaoru Taira

University of the Ryukyus

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Takao Higa

University of the Ryukyus

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Tsutomu Isa

University of the Ryukyus

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Hideaki Shimoji

University of the Ryukyus

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