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M Dohmoto

Publications and source records attributed to M Dohmoto.

At least 19 recordsLinked to original sources
PubMed1999

Structural analysis of the TNIT4 genes encoding nitrilase-like protein from tobacco.

Nitrilase (nitrile aminohydrolase, EC 3.5.5.1) catalyzes the hydrolysis of indole-3-acetonitrile (IAN) to indole-3-acetic acid (IAA). The Arabidopsis thaliana genome has four nitrilase genes (NIT1 to NIT4), while tobacco (Nicotiana tabacum) has only NIT4 homologs (TNIT4A and TNIT4B) and no NIT1 to NIT3 homologs. We have cloned the promoter region of TNIT4B and determined the transcriptional start sites which are the same sites in both TNIT4A and TNIT4B. The TNIT4 genes are expressed in various organs at low levels. The positions of the exon-intron splicing junctions in Arabidopsis NIT1 to NIT3 are completely conserved in TNIT4A.

Aminohydrolases↗
PubMed1998

The author replies

Explore the source record for details and available documents.

Journal Article↗
PubMed1998

Endosonography-guided biopsy of mediastinal and pancreatic tumors.

BACKGROUND: Although endoscopic ultrasound (EUS) allows sensitive imaging of the upper gastrointestinal (GI) tract, it remains difficult to differentiate between benign and malignant lesions on the basis of ultrasound morphology. The purpose of this study was to determine the value of EUS-guided biopsy for the diagnosis of submucosal and extraluminal tumors. METHODS: EUS-guided biopsy was carried out in 50 patients with upper GI-tract lesions. All patients were examined using a flexible echoendoscope with a 5/7.5 MHz curved array transducer. A specially designed biopsy device (type Vilmann) with a fine needle (diameter 0.8 mm) was used for EUS-guided biopsy. RESULTS: EUS-guided biopsy was performed for evaluation of mediastinal lesions (n = 15), pancreatic tumors (n = 26) and submucosal (n = 5) or stenotic tumors of the esophagus (n = 4). Fine-needle aspiration yielded diagnostic tissue samples in 44 of 50 patients (88%). Histology demonstrated benign lesions in 20 of 44 patients and malignant tumors in the other 24 patients. EUS-guided biopsy failed in only six patients (12%): in four patients it was impossible to advance the needle into very hard pancreatic tumors; non-representative biopsy material was obtained in two further cases. The results of EUS-guided biopsy were validated by surgery (n = 21), autopsy (n = 3) or clinical follow-up (n = 20). After a mean follow-up of 16 months there is no evidence of malignancy in any of the patients with benign histology. The sensitivity and specificity of EUS-guided biopsy in the diagnosis of malignancy were 88% and 100%, respectively. None of the patients experienced complications related to endosonographic biopsy. CONCLUSIONS: EUS-guided biopsy with the Vilmann needle device is a safe and accurate method for tissue sampling of extraluminal lesions. This technique considerably improves the diagnostic value of endosonography.

Adenocarcinoma↗
PubMed1997

Application of rectal stents for palliation of obstructing rectosigmoid cancer.

BACKGROUND: The rationale of palliative endoscopic treatment is to avoid a colostomy in patients with advanced disease and limited life expectancy. This study was conducted to evaluate the role of endoscopic stent implantation for palliation of obstructing rectal cancer. METHODS: Overall, 19 patients (aged 47-87 years) with nonresectable or metastatic rectal cancer were treated by stent insertion after laser recanalization or dilation. Three types of stents, i.e., plastic tubes (n = 8), self-expanding mesh stents (n = 6), and endocoil stents (n = 5), were used to maintain luminal patency. RESULTS: Endoscopic stent implantation was successfully performed in all 19 patients. Long-term luminal patency and satisfactory bowel function were achieved in 16 of 19 patients (84%). After a median follow-up of 6 months, eight of the patients have died and eight are still alive without evidence of recurrent obstruction. Dislocation of the endoprosthesis occurred in two of eight plastic tubes and one of five mesh stents. Recurrent obstruction due to tumor ingrowth was only observed in patients treated with self-expanding mesh stents (n = 2). In spite of reinsertion and laser therapy a colostomy was required in three of 19 patients. There was no evidence of treatment failure in five patients who received endocoil stents. None of the patients experienced serious complications related to the endoscopic procedure. CONCLUSIONS: Endoscopic stent implantation seems to be a safe and efficient palliative approach to selected patients with obstructing rectal cancer. Currently, self-expanding coil stents are superior to other devices because of lower risk of dislocation and tumor ingrowth.

Aged↗
PubMed1996

Evaluation and biopsy of recurrent rectal cancer using three-dimensional endosonography.

PURPOSE: The value of endorectal ultrasonography for postoperative follow-up of rectal cancer is limited by the inability to distinguish recurrent malignancy from benign lesions, e.g., fibrotic tissue. This study was conducted to investigate the role of three-dimensional (3D) endosonography for evaluation and biopsy of recurrent rectal cancer. METHODS: Endorectal ultrasonography was performed in routine follow-up program after resection of rectal cancer. 3D volume scans were recorded using a bifocal multiplane 3D transducer (7.5/10 MHz) with a 100 degrees longitudinal and a 360 degrees transversal scan angle. For transrectal ultrasound-guided biopsy of pararectal lesions, a specially designed targeting device was attached to the endoprobe. RESULTS: Overall pararectal lesions were detected in 28 of 163 patients (17 percent) who were undergoing endorectal ultrasonography for follow-up after resection of rectal cancer. 3D image analysis facilitated assessment of suspicious pararectal lesions by contemporary display of three perpendicular scan planes or volume reconstructions of the scanned area. Ultrasound-guided biopsy was performed in all 28 patients with pararectal lesions identified by endorectal ultrasonography. Biopsy revealed recurrent disease or lymph node metastases in seven and two patients, respectively. Benign lesions explained the endosonographic findings in 17 patients. All patients with benign histology still have no evidence of recurrent disease after a median follow-up of seven months. Nonrepresentative material was obtained in only 2 of 28 patients (accuracy, 93 percent). Histology changed the endosonographic diagnosis in 28 percent of cases. CONCLUSIONS: 3D endosonography with ultrasound-guided biopsy improves the diagnosis of extramural recurrence after curative resection of rectal cancer. 3D image display allows precise control of the position of the biopsy needle within the target.

Biopsy↗
PubMed1996

Endoscopic treatment of a choledochocele in a 2-year-old child.

Choledochocele is an extremely rare congenital lesion of the biliary tree causing abdominal pain, pancreatitis, and obstructive cholestasis. Traditionally the therapy for this malformation has been surgery. Recently endoscopic therapy has been utilized alternatively for the treatment of choledochocele in adults. We report the case of a 2-year-old girl with a choledochocele who was treated by endoscopic sphincterotomy and placement of a biliary stent. The prosthesis was removed after 4 months. After a follow-up of 20 months the patient remains free of symptoms. Our experience suggests that endoscopic treatment of congenital biliary disease can be performed accurately. Further studies will be necessary to confirm the value of stent implantation in congenital bile duct stenosis.

Child, Preschool↗
PubMed1996

Endosonography and endosonography-guided biopsy of upper-GI-tract tumors using a curved-array echoendoscope.

BACKGROUND: The purpose of the present study was to evaluate the accuracy of endoscopic ultrasonography (EUS) with a curved-array transducer and to determine the value of endosonography-guided biopsy. METHODS: EUS was performed in 162 consecutive patients for preoperative staging of gastric or esophageal cancer (n = 122) or for EUS-guided biopsy (n = 40). All patients were examined using a flexible echoendoscope (Pentax FG32-UA) equipped with a 7.5-MHz curved-array transducer. A specially designed fine needle was used for EUS-guided biopsy of submucosal or extrinsic lesions. RESULTS: Surgery was performed in 19 of 48 patients with esophageal cancer and 60 of 74 patients with gastric cancer. The accuracy in the assessment of the infiltration depth of esophageal cancer and in the determination of lymph node involvement was 84% and 88%, respectively. In gastric cancer the tumor infiltration depth was assessed correctly in only 65% of the patients. The identification of early gastric cancer proved to be a major problem. The accuracy in the detection of lymph node involvement was 73%. Obstructing tumors were examined in 17 patients with carcinoma of the esophagus or the gastric cardia. The accuracy of EUS in determining the T-stage and the N-stage of stenotic tumors was 88% and 86%, respectively. Endosonography-guided needle biopsy was successfully performed in all 40 patients. Histologic analysis revealed malignancy in 50% of the patients. Only two biopsy specimens contained nonrepresentative material (accuracy: 95%). No complications were observed related to the procedure. CONCLUSIONS: EUS with a curved-array transducer provides high accuracy rates in staging of esophageal carcinoma. Evaluation of gastric cancer with this technique appears to be more difficult than with radial transducers. A major advantage of the linear transducer is the ability to perform EUS-guided biopsies of submucosal or extamural lesions.

Adenocarcinoma↗
PubMed1996

Palliative endoscopic therapy of rectal carcinoma.

Curative surgery is not feasible in a considerable proportion of patients with rectal cancer because of extensive local spread or metastatic disease. However, most of these patients require palliative treatment to improve the symptoms of the disease, e.g. obstruction, pain and haemorrhage. Palliative surgery may be associated with a morbidity of 20-40% and a mortality of more than 10%. Endoscopic procedures can provide effective palliation with less complications. Before the development of lasers, endoscopic electrocoagulation and cryosurgery were used with some success. Currently, endoscopic Nd:YAG photocoagulation must be considered the treatment of choice in non-resectable rectal cancer. Laser therapy allows effective palliation in 85-95% of the patients, and generally, treatment-related complications occur in less than 10% of the patients and mortality is negligible. Transanal endoscopic resection may be effective in selected patients. New approaches to endoscopic palliation include photodynamic therapy (PDT) and implantation of self-expanding metal stents.

Cryosurgery↗
PubMed1995

[Endoscopic drainage of pancreatic pseudocysts].

AIM OF STUDY: To compare retrospectively the endoscopic treatment of pancreatic pseudocysts by retrograde pancreatic drainage (ERPD), cystogastrostomy (ECG) or cystoduodenostomy (ECD). PATIENTS AND METHODS: Between 1987 and 1995 pancreatic pseudocysts were successfully treated endoscopically in 30 patients (13 women, 17 men; mean age 49 [18-89] years): ERPD was accomplished through papillary insertion of 5-7 F prostheses into the cysts or pancreatic duct in 9 patients; ECG achieved drainage of cysts in the body or tail of the pancreas in 15 patients, and ECD for cysts in the head of the pancreas in three. Combined ERPD and ECG was necessary in three patients. RESULTS: Significant pain relief was achieved in all patients, accompanied by increased appetite and weight. Occlusion or dislocation of the prosthesis required renewed endoscopic drainage in three patients. The prostheses were removed, 2-12 months after implantation, when pain relief had occurred and clinical as well as radiological findings had become normal. Recurrence 10-22 months after removal of the drain was observed in four patients, of whom two had a successful second drainage procedure. Surgical intervention became necessary in three patients because of inadequate drainage or (one case) bleeding. CONCLUSION: These data indicate that endoscopic drainage of pancreatic pseudocysts gives good results with a low complication rate and no deaths. The procedure is thus an alternative to the at present prevailing operative treatment.

Adolescent↗
PubMed1995

Cancer of the rectum--palliative endoscopic treatment.

Three methods of palliative endoscopic treatment of malignant strictures of the rectum are presented: laser therapy and its combination with the implantation of either plastic prostheses, or self-expanding metal stents. The aim of all procedures is to avoid a colostomy at least in older patients with shorter life expectancy and incurable tumours. The additional application of a stent maintains the luminal patency and prevents the repetition of laser therapy. Since 1988 we have treated 60 patients with these techniques. First, two to six sessions of laser therapy were necessary for recanalization of the stenosis. In the time following this the patients returned two to eight times for regular laser therapy before they died from the carcinoma. In spite of laser therapy one patient developed an obstruction and another suffered from an iatrogenic perforation of the rectal cancer. In both cases a stoma was fashioned. To avoid repetitive laser sessions we successfully inserted a plastic endoprosthesis in seven cases. In another two cases the implantation failed because of perforation and the patients had to undergo surgery. For the next 10 cases we have used flexible self-expanding metal stents. Serious complications or signs of re-obstruction were not observed until the patients' death. The survival time ranged from 2 to 25 months.

Aged↗
PubMed1990

Management of chronic pancreatitis with pancreas cyst by endoscopic pancreatic prosthesis.

Cases of chronic pancreatitis accompanied by stenosis or dilation of the pancreatic duct were treated by endoscopic placement of an endoprosthesis and drainage. The purpose of the treatment was the alleviation of pain, restoration of extrapancreatic secretion and retardation of the progression of inflammation. The procedure was performed successfully in 9 of 13 patients, using an endoscopically placed pigtail prosthesis in the pancreatic duct. The successfully treated patients consisted of 9 cases of chronic pancreatitis, 2 cases being pancreas divisum. After disappearance of the symptoms and abnormal endoscopic findings, the drainage tubes were removed after a period of 5-12 months. No serious complications were encountered. Following the procedure, an improvement in appetite and increase of 2-13 kg in body weight was recognized. This method yielded satisfactory results in the treatment of chronic pancreatitis.

Adult↗
PubMed1985

[Endoscopic injection treatment].

Nowadays injection treatment is not only used for sclerosing esophageal varices but also for stopping hemorrhage from mucosal lesions. This method is equally effective for treatment of hemorrhages after polypectomies and papillotomies. New indications for this method are benign and malignant stenoses of the esophagus. Good results in sclerosing of varices and of stopping hemorrhage have been confirmed very often; however further experience is needed in the treatment of stenoses.

Ampulla of Vater↗
PubMed1982

[Palliative treatment of inoperable tumors of the efferent bile ducts].

Our method of percutaneous transhepatic cholangiodrainage (PTCD) and radiotherapy shows better results and prognosis in patients with inoperable tumors of the liver, biliary system and pancreas. PTCD was performed in patients with progressive obstructive jaundice due to inoperable tumors to decompress the hepatobiliary system and to reduce jaundice. This was combined with radiotherapy which was performed pre- and postoperatively and without operation. Aim of radiotherapy was to reduce the tumor and also to explore the possibility of radical operation. Radiotherapy was carried out in most patients with Linear accelerator (Linac), and in some with Betatron or Telecobalt 60. In a few cases was chosen: 1) two phase radiotherapy 2) and/or a combination of ray therapies. Inoperable tumors, which can not be excised, should be treated intraoperatively with radiation therapy. Only after a radiation with 3000-4000 rad linac, tumors showed shrinkage in size and at the same microscopic degenerative changes in tumor cells were observed.

Adenocarcinoma↗