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Biomedical subjects

T Muto

Publications and source records attributed to T Muto.

At least 271 records · Page 15Linked to original sources
PubMed1996

Flat adenoma as a precursor of colorectal carcinoma in hereditary nonpolyposis colorectal carcinoma.

BACKGROUND: Because flat adenoma shows a higher malignancy rate compared with other types of polyps, it is considered to play an important role in the carcinogenesis of colorectal carcinoma. In the present study, we examined flat adenomas in hereditary nonpolyposis colorectal carcinoma (HNPCC) patients. METHODS: Nine HNPCC patients who presented with flat adenomas were examined. All patients underwent either surgery or endoscopic polypectomy for colorectal carcinoma and/or adenoma. In all patients, annual colonoscopy had been performed once a year throughout the follow-up period after the initial treatment. When colorectal polyps were detected during follow-up colonoscopy, all lesions were endoscopically excised. Clinicopathologic features and microsatellite instability of both malignant lesions and adenomas were examined. RESULTS: Thirteen malignant lesions were detected: seven advanced carcinomas and six early carcinomas. Among 4 early carcinomas with submucosal invasion, 3 lesions (75%) were categorized as superficial type, with a configuration similar to flat adenoma. The frequency of flat adenoma was strikingly high in HNPCC patients in the present study. Among 73 polyps detected, 37 (50.7%) were flat adenomas. Both malignant lesions and flat adenomas had proximal predominance, 61.5% and 59.5%, respectively. Eleven of 15 lesions (73.3%) showed replication error. CONCLUSIONS: These results suggest the importance of flat adenoma as a precursor of colorectal carcinoma in some groups of HNPCC patients. Further study is essential to elucidate the natural history of flat adenomas in HNPCC patients.

Adenoma↗
PubMed1996

Identification of genes differentially expressed in B16 murine melanoma sublines with different metastatic potentials.

B16-F10 and B16-BL6 are B16 mouse melanoma sublines that preferentially metastasize to the lung following i.v. and s.c. injections, respectively. To study molecular mechanisms underlying the different metastatic behaviors exhibited by the B16 melanoma sublines, we performed differential hybridization of the genes transcribed in these cells and compared their expression levels. We isolated four genes that were highly expressed in B16-F10 cells but not in B16-BL6 cells: TI-225 (polyubiquitin), TI-229 (pyruvate kinase), TI-241 (LRF-1 homologue), and TI-227 (novel gene). Triosephosphate isomerase, 10-formyltetrahydrofolate dehydrogenase, tyrosinase-related protein 2, cytochrome c oxidase, ATP synthetase alpha subunit, RNA helicase, and ribosomal protein (L37, J1, acidic phosphoprotein), however, showed higher expression in B16-BL6 cells than in B16-F10 cells. Among these clones, transfection of TI-241 into the low metastatic clone F1 converted the parental cells from low- into high-metastatic cells. TI-241 may regulate the expression of various genes as a transcription factor in the complex process of metastasis.

Amino Acid Sequence↗
PubMed1996

Exocrine function of caerulein-induced acute pancreatitis in anesthetized rats.

Exocrine function was studied in anesthetized rats that had received two specific doses of caerulein (maximal stimulation and supramaximal stimulation). Male Wistar rats (body weight, 200-250 g) were divided into three groups: the control group (4-h saline infusion), the maximal stimulation group (0.25 microgram/kg per h caerulein for 4 h), and the caerulein pancreatitis group (10 micrograms/kg per h for 4h). Histologically, interstitial edema and cytoplasmic vacuolization were observed only in the caerulein pancreatitis group, with no abnormal findings in the other groups. The volume of pancreatic juice was significantly increased in both the maximal stimulation group and the caerulein pancreatitis group. The protein output and the amylase output in the 1st h of caerulein infusion were also significantly increased, to 459% and 338% in the maximal stimulation group, and to 925% and 1430% respectively, in the caerulein pancreatitis compared to the baseline values. We also found that the pancreatic juice of the caerulein pancreatitis group contained precipitated protein, and high trypsin activity, and protein degradation was confirmed by electrophoresis. These findings were not observed in the other groups. These results strongly suggest that hypersecretion and the appearance of trypsin activity in pancreatic juice plays an important role in the induction of histological changes in this pancreatitis model in anesthetized rats.

Acute Disease↗
PubMed1996

Interleukin-6 and stress hormone responses after uncomplicated gasless laparoscopic-assisted and open sigmoid colectomy.

PURPOSE: Laparoscopic colectomy has increasingly been advocated as an option for treatment of colonic disease. The purpose of this study was to compare effects of laparoscopic-assisted sigmoid colectomy (LAS) and conventional open colectomy (OPEN) on postoperative cytokine and stress hormone responses. METHODS: Fourteen patients with sigmoid colon cancer, apparently free of preoperative complications, were analyzed. Patients in both groups underwent sigmoid colectomy with lymphadenectomy. LAS was performed by the gasless abdominal wall-lifting method. A 5 cm incision was placed at the beginning of the operation. Blood samples were taken preoperatively and postoperatively for measurement of interleukin-6, glucagon and C-reactive protein. Urinary catecholamine excretions were also determined postoperatively. RESULTS: The two groups of patients were similar with respect to age (61 +/- 7 for LAS vs. 64 +/- 9 for OPEN) and sex. Intraoperative blood loss did not differ significantly between groups (112 +/- 97 ml for LAS vs. 366 +/- 380 ml for OPEN). Operative times for LAS tended to be longer than those for OPEN (231 +/- 67 vs. 169 +/- 45 minutes; P = 0.08). Similar time courses of postoperative interleukin-6, C-reactive protein, and stress hormone responses were observed in both groups. No significant differences were observed in the magnitude of changes except that the serum interleukin-6 level on day of surgery (postoperative day 0) was significantly higher in LAS patients than in those receiving OPEN. In addition, interleukin-6 levels showed a significant positive correlation with operative duration (r = 0.582; P < 0.05). CONCLUSIONS: Data suggest that stress responses after sigmoid colectomy, in patients undergoing LAS, are comparable with those of patients receiving OPEN and that the early interleukin-6 response after surgery appears to be associated with operative time.

Aged↗
PubMed1996

Overexpression of p53 protein and histologic grades of dysplasia in colorectal adenomas.

PURPOSE: To clarify the relation between tumor-suppressor gene p53 expression and histologic grades of dysplasia in colorectal adenomas, we performed immunohistochemical analysis in a series of 59 colorectal polyps and 40 advanced carcinomas. METHODS: Adenomatous polyps were stained by hematoxylin and eosin and classified into mild, moderate, and severe dysplasia (intramucosal carcinoma), according to the World Health Organization's classification. RESULTS: p53 was positive in 7.1 percent (2/28) of mild, 29.4 percent (5/17) of moderate, and 62.5 percent (5/8) of severe dysplasia. In submucosal and advanced carcinomas, positivity rates were 75 percent (3/4) and 47.5 percent (19/40), respectively. Different staining patterns were found, according to grades of dysplasia. In the adenomas with mild or moderate dysplasia, a few focal crypts showed localized p53-positive staining. Adenomas with severe dysplasia had two different staining types. One was a focal staining type as shown in mild or moderate dysplasia; the other was a diffuse staining type, in which glands with mild or moderate dysplasia, surrounding severe dysplasia area, were also stained. Submucosal and advanced carcinomas showed a strong positive staining in cancer cells only. CONCLUSIONS: Overexpression of p53 protein in adenomas with mild or moderate dysplasia and existence of two types of expression in adenomas with severe dysplasia were observed. These facts suggested the possible existence of different pathways in the adenoma to carcinoma progression.

Adenoma↗
PubMed1996

Effects of three inhibitors of nitric oxide synthase on host resistance to bacterial infection.

OBJECTIVE: To examine the effects of three nitric oxide synthase inhibitors on survival in a murine sepsis model. DESIGN: Prospective randomized experimental trials. SETTING: Laboratory. SUBJECTS: Female Balb/c mice. INTERVENTIONS: Escherichia coli (10(8) colony-forming-units/body) were injected into the peritoneal cavities of Balb/c mice. NG-nitro-L-arginine-methyl-ester, NG-monomethyl-L-arginine, or N-iminoethyl-L-ornithine was given at various concentrations, intraperitoneally, one hour before bacterial challenge. MEASUREMENTS: One hundred and fifteen animals were observed for survival. RESULTS: These inhibitors provided the mice no protection from the bacterial challenge. Notably, pretreatment with NG-nitro-L-arginine-methyl-ester (100 mg/kg i.p.) actually reduced survival time after E. coli challenge. CONCLUSIONS: Inhibition of nitric oxide production improved neither the survival time nor rate in this murine sepsis model.

Animals↗
PubMed1996

Mucin-producing adenoma associated with pancreas divisum and hepatic hilar carcinoma: an autopsy case.

We present the autopsy case of an 82-year-old Japanese woman with a mucin-producing adenoma accompanied by pancreas divisum and a hepatic hilar carcinoma. She had suffered from a cholangiocellular carcinoma at the hepatic hilus for 2 months, which was treated with radiation and chemotherapy. She did not complain of any abdominal pain. Obstructive jaundice deteriorated despite percutaneous transhepatic bile duct drainage, and she died of hepatic insufficiency. At autopsy, a hepatic tumor was confirmed to have caused severe obstructive jaundice. Histological examinations showed moderately to poorly differentiated cholangiocellular adenocarcinoma with squamous metaplasia, probably due to radiation. A yellowish mucinous tumor was found in the head of the pancreas near the minor papilla. It consisted of multiple rice-sized cystic lesions with thin septa. Although it had no capsule, its margin was clear. Neither a wide opening of the major or minor papilla nor mucous drainage was observed. Gross examinations revealed unfused pancreatic ducts. The slightly dilatated dorsal duct and a branch of the mildly dilatated ventral duct showed tumor involvement. Histological examinations showed mild atypia of the epithelia, and this pancreatic tumor was diagnosed as branch duct-type mucin-producing adenoma with postradiation dysplasia. The combination of a mucin-producing tumor and pancreas divisum is rare, and this is only the third reported case.

Adenoma↗
PubMed1996

Ulcerative colitis with overexpression of p53 preceding overt histological abnormalities of the epithelium.

A 53-year-old man with a 22-year history of ulcerative colitis(UC) (pancolitis), had an ulcerating rectal tumor. Resection of the rectum and sigmoid colon was performed. Pathology showed an expansive ulcerating adenocarcinoma tumor (type 2) invading the adventitia against a background of UC in a resolving phase. Dysplasia was also found in granular and flat mucosa adjacent to the invading carcinoma. Immunostaining for p53 showed diffuse positivity in both the carcinoma and dysplasia, and also in the mucosa with indefinite dysplasia or no dysplasia neighboring the dysplasia and carcinoma. Mapping of neoplasms and the area with p53 protein overexpression showed that the grade of dysplasia increased as the lesion approached the invasive carcinoma and that the mucosa with dysplasia was surrounded by mucosa without dysplasia or indefinite for dysplasia, but with p53 protein overexpression. In some areas without dysplasia showing p53 overexpression, there was significant morphometric enlargement of the area and diameter of the nucleus p53 Immunostaining is a good marker for assessing the genetic alterations that precede histological abnormalities and for diagnosing carcinoma in UC. Objective findings such as p53-protein overexpression and morphometric values should be used to evaluate cytological abnormalities in UC, as well as in common colorectal cancer.

Adenocarcinoma↗
PubMed1996

Pancreatic exocrine function during acute exacerbation in WBN/Kob rats with spontaneous chronic pancreatitis.

CONCLUSION: Pancreatic exocrine hypofunction is markedly deteriorated during acute exacerbation in a rat model with chronic pancreatitis. BACKGROUND: Little is known about pancreatic exocrine function during acute exacerbation in patients with chronic pancreatitis. We investigated changes in pancreatic exocrine function after inducing acute pancreatitis in an animal model of spontaneous chronic pancreatitis. METHODS: WBN/Kob rats with chronic pancreatitis sequentially underwent pancreatic exocrine function test 1-6 d after surgical preparation with external pancreatic fistula. We induced acute pancreatitis in another WBN/Kob rats by i.v. administration of cerulein at a rate of 10 micrograms/kg/h for 4 h 4 d after surgical preparation. Pancreatic exocrine function test was undertaken in a conscious state 1 d before and after cerulein administration. RESULTS: In WBN/Kob rats not given cerulein, pancreatic exocrine function remained almost constant at 3-6 d after surgery. Marked hyperamylasemia developed immediately after cerulein administration. After its administration, the pancreas microscopically showed prominent interstitial edema and intracellular vacuolization of acinar cells in addition to the finding of pre-existing chronic pancreatitis. Basal and cholecystokinin-stimulated flow rate, bicarbonate output, and protein output, which were substantially impaired 1 d before cerulein administration, were further reduced 1 d after its administration.

Acute Disease↗
PubMed1996

Effects of pancreatic duct ligation and aging on acute taurocholate-induced pancreatitis. Experiments in the perfused pancreas in rats.

CONCLUSION: When taurocholate was injected into the common bile duct, high ductal pressure due to ligation of the pancreatic duct did not produce more damage in the pancreas of both old rats and young adult rats, and levels of pancreatic enzymes in portal venous effluent were lower in old rats than in younger rats. BACKGROUND: The effects of ligation of the pancreatic duct and aging on acute pancreatitis caused by taurocholate are still unclear. METHODS: Young adult and old male Wistar rats were used. Six hours after ligation of the common bile duct in both the duodenum and liver hilus, rats were killed and the pancreata were perfused. Taurocholate or normal saline was injected retrogradely into the common bile duct. The levels of amylase and lipase in the portal venous effluent were determined as markers of damage to the pancreas. The pancreas was also histologically examined after the perfusion experiments using an Image Analysis System. RESULTS: (1) A nonsignificant elevation of pancreatic enzymes was found in portal venous effluent by the retrograde injection of saline into the common bile duct. Injection of taurocholate caused a marked elevation of enzymes in the effluent for the first 30 min after injection, which then gradually decreased. (2) Basal levels of pancreatic enzymes were significantly higher in the ligation group than in the nonligation group. Injection of saline into the common bile duct had no apparent effect on enzymes in the effluent. In contrast, taurocholate injection into the common bile duct produced a marked increase in enzymes in the portal venous effluent. However, no significant difference was found between the ligation group and the nonligation group. (3) Similar findings were obtained when old rats were used. (4) Although basal levels of enzymes were almost the same in nonligated old and young adults rats, taurocholate injection into the pancreatic duct in old rats resulted in a significant depression of enzymes compared to that in young adult rats. In the ligation group, pancreatic enzymes in the portal venous effluent following taurocholate injection tended to be lower in old rats than in young adult rats. The results were histologically supported in that various degrees of fibrosis were found in the pancreata of old rats.

Acute Disease↗
PubMed1996

Intramural metastases from thoracic esophageal cancer: local indicators of advanced disease.

The patterns of tumor spread and long-term survival of patients with (n = 54) and without (n = 270) intramural metastasis from esophageal cancer were investigated after either extended radical (n = 155) or less radical (n = 169) esophagectomy. The purpose was to evaluate whether extended radical esophagectomy has an impact on the long-term survival of patients with intramural metastases from the disease. The patients with intramural metastasis had significantly larger primary tumors (p < 0.01) and more frequent T4 tumors (p < 0.001), stage IV disease (p < 0.05), lymphatic invasion (p < 0.05), and lymph node metastasis (p < 0.01) than did those without intramural metastasis. The survival rates of patients with intramural metastases were significantly worse than those of patients without intramural metastases after resection (p < 0.001). No patient with intramural metastases survived more than 4 years after either extended or less radical esophagectomy, and there was no significant difference between the two survival curves. Therefore intramural metastases should be considered local indicators of advanced esophageal cancer, and radical esophagectomy may not be indicated for patients with intramural metastasis from the disease.

Aged↗
PubMed1996

Spontaneous perforation of a non-aneurysmal atherosclerotic abdominal aorta or femoral artery.

The spontaneous perforation of a non-aneurysmal atherosclerotic abdominal aorta or femoral artery is reported. Over the past 14 years, four perforations have been found in the abdominal aorta and one in the femoral artery; the incidence of each was 1.1% and 5.9%, respectively. Computed tomography scanning was useful for diagnosing pseudoaneurysms in all cases, since it revealed haematoma outside the arterial wall. One of these cases presented with an aortoduodenal fistula. The arteries were severely atherosclerotic with calcification. All of the patients underwent a graft replacement. Operative findings confirmed pseudoaneurysm. One patient died from pneumonia 4 months after the operation, and the other four have remained well during the follow-up period ranging from 2-9 years.

Aged↗
PubMed1996

The mode of lymphatic spread in carcinoma of the bile duct.

BACKGROUND: Knowing the prevalence of lymph node involvement associated with the location of the primary tumor is a prerequisite for operating with curative intent in carcinoma of the bile duct. METHODS: We evaluated 80 patients with carcinoma of the bile duct or cystic duct to investigate the frequency of lymph node involvement, the mode of lymphatic spread, and prognosis, according to the location of the primary tumor. RESULTS: The frequency of lymphatic spread of carcinomas in the proximal, middle, and distal bile ducts, excluding seven T1 tumors, was 48%, 67%, and 56%, respectively. With regard to the mode of lymphatic spread: (1) a metastatic pathway along the common hepatic artery predominated over that to the retropancreatic area in the proximal duct carcinoma group; (2) in the middle duct carcinoma group, metastatic lymph nodes were distributed widely, involving nodes around the superior mesenteric artery or at the para-aortic area; and (3) in the distal duct carcinoma group, metastatic nodes generally were localized around the head of the pancreas. CONCLUSIONS: Understanding the mode of the lymphatic spread according to the primary tumor may be helpful for choosing the appropriate surgical approach with curative intent in bile duct carcinoma.

Adult↗
PubMed1996

Early detection of specific IgE antibody against house dust mite in children at risk of allergic disease.

OBJECTIVES: House dust mite (HDM) is a representative inhalant allergen that triggers allergic disease in childhood. The aim of this study is early detection of HDM-specific IgE antibody and prediction of the risk of a positive reaction to this antibody by in vitro parameters in infants with allergic manifestations. STUDY DESIGN: Levels of HDM IgE in a range below the standard cutoff point of 0.35 U/ml, serum concentrations of IgE, and specific IgE antibodies against egg white, cow milk, and soybeans were determined in 108 infants with allergic manifestations at 6 months of age, and these infants were monitored for conversion of HDM IgE to positive levels greater than 0.35 U/ml up to 5 years of age. The presence of active allergic disease at 5 years of age in relation to HDM-specific IgE was also examined. RESULTS: We were able to determine reliably the HDM IgE values between 0.23 and 0.35 U/ml, using a fluorescent enzyme immunoassay that measured the intensity of fluorescence. The HDM IgE levels increased, resulting in positive values, in 54 of 108 subjects during the first 5 years of life. In multiple regression analysis, an HDM IgE value between 0.23 and 0.35 U/ml, a high serum IgE level, and a positive reaction to specific IgE antibody against egg white in infants at 6 months of age proved to be significant predictors of the future positive reaction to HDM IgE (p = 0.0006, 0.0043, and 0.0001). In particular, the sensitivity and specificity of specific IgE antibody against egg white for the conversion of HDM IgE to positive values were the best among these indicators. Moreover, active allergic diseases were observed significantly more often in children with positive HDM IgE values than in children with negative HDM IgE values at 5 years of age (p < 0.001 for each). CONCLUSIONS: A determination of these predictors in infants at 6 months of age can be used for early detection of HDM IgE and would be valuable in a screening test for later allergic disease among infants with allergic manifestations.

Allergens↗
PubMed1996

Outcome of radical surgery for carcinoma of the gallbladder according to the TNM stage.

BACKGROUND: The role of surgery in the treatment of gallbladder carcinoma (GBC) is controversial. The outcome after prospective radical surgery for GBC is discussed on the basis of the TNM stage of the tumor. METHODS: One hundred six patients who had undergone radical surgery were selected. The standard radical procedure consisted of a cholecystectomy accompanied by lymph node dissection, wedge resection of the liver, and resection of the extrahepatic bile ducts. The stage was determined by pathologic examination of resected specimens. RESULTS: Lymph node metastases were identified in no patients with T1 tumors (n = 15), 48% of patients with T2 tumors (n = 46), 72% of patients with T3 tumors (n = 25), and 80% of patients with T4 tumors (n = 20). One patient died within 30 days after radical surgery (mortality rate, 0.9%). There were 35 5-year survivors including 11 patients with nodal involvement, 10 with stage I tumors, 13 with stage II tumors, 10 with stage III tumors, and 2 with stage IV tumors. The cumulative 5-year survival rate in patients with stage I tumors was 91% (n = 15), 85% in patients with stage II tumors (n = 24), 40% in patients with stage III tumors (n = 28), and 19% in patients with stage IV tumors (n = 39). In patients with stage III and IV tumors the 5-year survival rate was 52% after curative resection (n = 35). This was significantly better than the 5% 5-year survival rate after a noncurative resection (n = 32). CONCLUSIONS: The presence of lymph node metastases is strongly influenced by the depth of invasion of the primary tumor. Accurate determination of the TNM stage is essential in comparing surgical results, predicting patient outcome, and planning additional treatment. Standard radical surgery contributes to patient survival and is recommended in patients with advanced GBC.

Adult↗