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Hiroyuki Isayama

Publications and source records attributed to Hiroyuki Isayama.

25 records · Page 2Linked to original sources
PubMed2002

Quantity of mutant K-ras gene in pancreatic secretions for diagnosis of pancreatic carcinoma with different assays: analysis of 100 patients.

BACKGROUND: Two types of quantitative assay kits for K-ras mutations, PCR-preferential homoduplex formation assay (PHFA) and enriched PCR and enzyme-linked mini-sequence assay (ELMA), were recently developed. The K-ras mutations were analyzed using these assays. MATERIALS AND METHODS: DNA was extracted from the pancreatic juice which was obtained by endoscopy from 38 patients with pancreatic neoplasms (23 adenocarcinomas and 15 intraductal papillary neoplasms) and from 62 without it. RESULTS: The results of the two methods were mutually correlative. K-ras mutation was detected at high levels (mutant ras genes occupied >2% of all K-ras genes) in 25 of the 38 cases (66%) with pancreatic neoplasm. It was also detected at high levels in 9 of the 14 cases (64%) with pancreatic cyst. In contrast, the mutant gene was detected at a lower level (<2%) in other cases. CONCLUSIONS: Quantitative analysis of the mutant ras gene provided a useful tool for diagnosing the pancreatic carcinoma when the percentage of the mutant is high, especially when the types of mutation were either GAT or GTT.

Adenocarcinoma↗
PubMed2002

Polyurethane-covered metal stent for management of distal malignant biliary obstruction.

BACKGROUND: The efficacy of polyurethane-covered metal expandable stents for treatment of neoplastic distal biliary obstruction was analyzed. METHODS: Twenty-one patients with unresectable malignant tumors involving the mid to distal bile duct who were seen with obstructive jaundice were consecutively enrolled. Eighteen patients underwent endoscopic implantation of a polyurethane-covered metal stent and 3 patients underwent transhepatic insertion because of duodenal obstruction. The stent patency, complications, and patient survival were analyzed. RESULTS: Effective biliary decompression was achieved in all patients. Adverse events were minor: mild pancreatitis (1) and cholecystitis (2) occurred within 7 days of stent insertion. Mean survival and stent patency were 233 days and 206 days, respectively. Stent occlusion occurred in 3 patients (14%) after a mean of 188 days. Tumor ingrowth through the stent mesh was not observed. However, 2 stents were occluded by tumor overgrowth and 1 by compacted alimentary debris. CONCLUSIONS: A polyurethane membrane may prevent tumor ingrowth and reduce the occlusion rate for expandable metal stents implanted in patients with malignant obstruction of the distal bile duct.

Adult↗
PubMed2002

Quantitative analysis of K-ras gene mutation in pancreatic tissue obtained by endoscopic ultrasonography-guided fine needle aspiration: clinical utility for diagnosis of pancreatic tumor.

OBJECTIVES: Endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) has become established in the diagnosis of pancreatic cancer. The combination of pathological diagnosis and analysis for mutant K-ras gene was investigated to improve the accuracy of diagnosis. METHODS: EUS-FNA was performed in 34 patients with pancreatic masses (26 adenocarcinomas and eight chronic pancreatitis). Mutant ras gene was analyzed semiquantitatively in the specimens obtained by EUS-FNA as well as in pancreatic juice obtained by ERCP. RESULTS: Mutant gene was detected at high amounts (more than 2% of total ras genes) in 20 of 26 (77%) specimens of EUS-FNA and in 12 of 19 (63%) of pancreatic juice in cases with pancreatic carcinoma. Cytological diagnosis of malignancy by EUS-FNA was found in 16 of 26 (62%) patients with pancreatic cancer. Accurate diagnosis of the carcinoma was 21 of 26 (81%) by combined cytology and molecular method of EUS-FNA, and increased to 23 of 26 (88%) by adding molecular analysis of pancreatic juice. In contrast, mutant gene was absent or low level despite suspicious cytology in patients with benign pancreatic lesion. CONCLUSION: Quantitative analysis of mutant ras gene supplemented conventional cytology of EUS-FNA and ERCP. Detection of mutation at high amounts may represent pancreatic cancer, whereas its absence increased the possibility of benign lesion.

Adenocarcinoma↗
PubMedDate not supplied

Histological analysis of the papilla after endoscopic papillary balloon dilation.

BACKGROUND/AIMS: Endoscopic papillary balloon dilation is an effective procedure in the management of bile duct stones and is believed to preserve the papillary function. The papillary architecture is also considered to be preserved. However, little is known about the effects of balloon dilation on papillary structure. The present study was conducted to elucidate these effects. METHODOLOGY: Since May 1994, endoscopic papillary balloon dilation was performed in 467 patients (407 patients for removal of bile duct stone, 57 for insertion of stent and 3 for baby cholangioscope). Of those, histological examinations were undertaken in 10 patients. The indications of endoscopic papillary balloon dilation were bile duct stone removal in 2 patients, stent insertion in 8. The specimens were obtained 2 to 63 weeks after endoscopic papillary balloon dilation during surgical operation in 6 patients and autopsy in 4 patients. Serial sections through the papilla were stained by hematoxylin and eosin and Masson's trichrome. The specimens were also obtained from 4 patients without biliary disease as control. RESULTS: No smooth muscle disruption nor architectural distortion was observed except for one patient who had mild disruption of smooth muscle caused by a biliary drainage tube. However, mild to moderate inflammation and fibrosis were seen in 9 patients and in 8, respectively. CONCLUSIONS: The papillary architecture is not affected by endoscopic papillary balloon dilation. This may imply that endoscopic papillary balloon dilation preserves papillary function.

Aged↗
PubMedDate not supplied

"Duodenal intussusception" due to adenoma of the papilla of Vater.

The case of a 55-year-old woman with a pedunculate adenoma of the papilla of Vater is presented. Diagnostic imaging modalities including ultrasonography, CT scan, magnetic resonance of cholangiopancreatography, simultaneous duodenography and cholangiography, and angiography showed a giant tumor protruding intraluminally and moving forward in the duodenum by peristalsis. It had a duodenal intussusception-like appearance, with remarkable left-lower deviation of the common bile duct and major pancreatic duct in the papilla of Vater as far as the left side of the aorta. Episodes of jaundice or ileus were absent, probably because the tumor was mobile in the duodenum. As biopsy specimens showed no malignancy and intraductal ultrasonography in the common bile duct revealed no intraductal invasion of the tumor in the papilla of Vater, the patient underwent transduodenal papillectomy with papilloplasty with pancreatic ductoplasty. Pathological diagnosis of consecutive specimens was a papillary adenoma with moderate atypia and occasional tubular structure. There seems to be an exceptional subtype of the tumor in the papilla of Vater, like this case, demonstrating the duodenal intussusception-like appearance without prominent clinical symptoms.

Adenoma↗
PubMedDate not supplied

Preserved function of the Oddi sphincter after endoscopic papillary balloon dilation.

BACKGROUND/AIMS: Endoscopic papillary balloon dilation (EPBD) is a safe and effective procedure for the treatment of bile duct stones that appears to be less hazardous to the sphincter of Oddi than endoscopic sphincterotomy. However, little is known about the function of Oddi muscle after EPBD. The aim of the present study is to evaluate Oddi muscle function using quantitative cholescintigraphy. METHODOLOGY: This study was conducted using 12 patients treated for bile duct stones by EPBD, and 8 patients treated by endoscopic sphincterotomy, followed by laparoscopic cholecystectomy thereafter. For the controls, 10 asymptomatic cholecystectomized patients were used. From 1-3 years after the interventional procedures, patients received a quantitative cholescintigraphy examination using 185 MBq of technetium-99m-N-pyridoxyl-5-methyl-tryptophan. The hepatic hilum-duodenum transit time on quantitative cholescintigraphy was measured as the time interval between the initial appearance of isotope activity at the hepatic hilum and that at the duodenum. RESULTS: Mean hilum-duodenum transit time in patients after EPBD (6.3 min, 95%CI 4.5-8.0) was not different from that in control patients (6.5 min, 95%CI 4.3-8.7), whereas mean hilum-duodenum transit time in endoscopic sphincterotomy patients (3.2 min, 95%CI 2.4-4.0) was markedly shorter than both the control and EPBD groups (p = 0.0053). CONCLUSIONS: The function of the sphincter of Oddi may be preserved after endoscopic papillary balloon dilation.

Adult↗