Biomedical subjects

M Tatsuta

Publications and source records attributed to M Tatsuta.

At least 163 records · Page 9Linked to original sources

PubMed1992

Early depressed adenocarcinomas of the large intestine.

From January 1987 to December 1990, five cases of early depressed cancer of the large intestine were seen. Endoscopically, almost all of these tumors were located in the proximal colon and looked like a reddish depression (similar to the sucker of an octopus). Histologically, all of these cancers were well differentiated and tended to reach deeper layers at an early stage. Four (80%) of these cancers were not associated with adenoma and were thought to have arisen de novo.

Adenocarcinoma↗

PubMed1992

Enhancement by thyroxine of experimental carcinogenesis induced in rat colon by azoxymethane.

The effect of thyroxine (T4) on the incidence, number and histology of colon tumors induced by azoxymethane (AOM), and on the labeling index of colon mucosa were investigated in Wistar rats. Rats were given AOM by injection once a week for 10 weeks, together with T4 in depot form until the end of the experiment. Administration of T4 resulted in a significant increase in the incidence of colon tumors in week 35. However, it did not influence the histological appearance of the colon tumors or the histological types and depths of involvement of colon adenocarcinomas. Furthermore, it caused a significant increase in the labeling index of the colon during, but not after, AOM treatment. Our findings indicate that T4 enhances the development of colon tumors, which may be related to its effect in increasing proliferation of epithelial cells in the colon mucosa during administration of the carcinogen.

Adenocarcinoma↗

PubMed1992

Enhancement by bombesin of colon carcinogenesis and metastasis induced by azoxymethane in Wistar rats.

The effects of bombesin on the incidence, number and histology of colon tumors induced by azoxymethane (AOM), and on their metastases to the peritoneum and/or lymph nodes, were investigated in Wistar rats. Rats received weekly s.c. injections of AOM for 10 weeks, and s.c. injections of bombesin in depot form every other day until the end of the experiment in week 30. Administration of bombesin significantly increased the incidence of colon tumors in week 30. It had no influence on the histological features or depths of involvement of colon adenocarcinomas, but significantly increased the incidence of cancer metastasis to the peritoneum and/or lymph nodes. It also caused a significant increase in the labeling index of the colon epithelial cells. Our findings indicate that bombesin enhances the development and metastasis of colon tumors, and that this effect may be related to its effect in increasing proliferation of epithelial cells of the colon.

Adenocarcinoma↗

PubMed1992

Enhancement by vaso-active intestinal peptide of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats.

The effects of vaso-active intestinal peptide (VIP) on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were investigated in Wistar rats given VIP every other day for 27 weeks after oral administration of MNNG for 25 weeks. In week 52, administration of VIP caused a significant increase in the incidence of gastric cancers, but did not influence their histological appearance. VIP significantly increased the labeling indices of the antral mucosa. Our findings indicate that VIP enhances gastric carcinogenesis, and that this effect may be related to its effect in increasing cell proliferation of the antral epithelial cells.

Animals↗

PubMed1992

A prospective trial of early detection of pancreatic cancer by ultrasonographic examination combined with measurement of serum elastase 1.

The accuracy of ultrasonographic examination combined with measurement of elastase 1 levels for early detection of pancreatic cancer was evaluated prospectively. Abdominal ultrasonographic examination and measurement of serum elastase 1 levels were done within 2 weeks after the initial visit to the clinic in a total of 2098 patients older than 35 years of age with symptoms suggesting pancreatic disease. Those in which one or both of these examinations had abnormal results underwent additional tests such as endoscopic retrograde cholangiopancreatography and computed tomography. Of those with pancreatosonograms with abnormal results with or without abnormally high serum elastase 1 levels, 19 patients eventually were found to have pancreatic cancer. No patients with pancreatic cancer, a normal level of serum elastase 1, and a pancreatosonogram with normal results were found, but follow-up studies revealed one pancreatic cancer in 189 patients after technically unsatisfactory ultrasonographic examination. In 9 (45%) of the 20 cases detected in this study, the pancreatic cancers were resectable, and two (10%) were less than 2.0 cm in longest diameter. These findings indicate that this combined examination is useful for early detection of pancreatic cancer. However, no pancreatic cancer was found in patients with abnormally high serum elastase 1 levels without a pancreatosonogram with abnormal results. Moreover, a combination of ultrasonographic examination and measurement of the elastase 1 level did not raise the diagnostic accuracy over that of ultrasonographic examination alone. These findings indicate that ultrasonographic examination alone is useful in screening for early pancreatic cancer.

Adult↗

PubMed1992

Inhibition of azoxymethane-induced experimental colon carcinogenesis in Wistar rats by 6-hydroxydopamine.

The effects of 6-hydroxydopamine (6-OHDA) on the incidence, number and histology of colon tumors induced by azoxymethane (AOM), and on norepinephrine (NE) concentration in the colon wall and the labelling index of the colon mucosa were investigated in Wistar rats. Rats received sub-cutaneous (s.c.) injections of AOM once a week for 10 weeks, and throughout 35 weeks were also given intraperitoneal (i.p.) injections of 6-OHDA. Prolonged administration of 6-OHDA was found to cause a significant reduction in the incidence and number of colon tumors. However, it had no influence on the histological features or depths of involvement of colon tumors and/or adenocarcinomas. Its administration also caused significant decreases in the NE concentration in the colon wall and in the labelling index of the colon mucosa. Our findings indicate that 6-OHDA has a protective effect against colon carcinogenesis, and that the activity of the sympathetic nervous system may have an important influence on colon carcinogenesis.

Adenocarcinoma↗

PubMed1992

Attenuating effect of ornithine decarboxylase inhibitor (1,3-diaminopropane) on bombesin enhancement of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine.

The effects of combined administration of bombesin and the ornithine decarboxylase (ODC) inhibitor 1,3-diaminopropane (DAP) on the incidence and number of gastric tumors induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), the ODC activity of the gastric wall and the labelling index of the gastric mucosa were investigated in inbred Wistar rats. Rats were given drinking water containing MNNG (50 micrograms/ml) for 25 weeks and then drinking water containing DAP (2.5 g/l) and/or injections of 40 micrograms/kg body weight of bombesin in depot form every other day. Administration of bombesin alone resulted in significant increases in the incidence of gastric cancers, the ODC activity of the antral portion of the gastric wall and the labelling index of the antral mucosa. Administration of DAP with bombesin significantly reduced enhancement by the latter of gastric carcinogenesis, ODC activity of the antral portion of the gastric wall and the labelling index of the antral mucosa. Our results suggest that ODC inhibition attenuated the enhancement of gastric carcinogenesis by bombesin, and that this enhancement by bombesin was mediated by polyamine biosynthesis.

Adenocarcinoma↗

PubMed1992

Enhanced induction of colon carcinogenesis by azoxymethane in Wistar rats fed a low-protein diet.

The effects of ad libitum feeding of synthetic, low-protein diets on the incidence, number and histology of colon tumors induced by azoxymethane (AOM), on the norepinephrine concentration in the colon wall tissue and on the labelling index of colon mucosa were investigated in Wistar rats. Rats received 10 weekly injections of 7.4 mg/kg body weight of AOM and were given synthetic diets of equal calorie content containing 25% casein (normal-protein diet), 10% casein (low-protein diet) or 5% casein (very-low-protein diet). Administration of the low- and very-low-protein diets resulted in significant increases in the incidence and number of colon tumors at week 30. However, it did not affect the histology of the colon tumors. The low- and very-low-protein diets also resulted in significant increases in norepinephrine concentration in the proximal and distal portions of the colon wall and in the labelling indices of both parts of the colon mucosa. Our findings indicate that low- and very-low-protein diets enhance colon carcinogenesis and that this may be related to their effects in increasing the norepinephrine level in the colon wall and in stimulating proliferation of colon epithelial cells.

Adenocarcinoma↗

PubMed1992

Promoting effect of ovariectomy on hepatocellular tumorigenesis induced in mice by 3'-methyl-4-dimethylaminoazobenzene.

The treatment of female C57BL/6 x DS-F1 mice with 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) at 10, 12, 14, 16 and 18 days of age resulted in the development of hepatocellular adenomatous nodules after 10 months of age. Ovariectomy in these mice at 1 month of age hastened the development of adenomatous nodules, which then first appeared at 8 months of age. The incidence of adenomatous nodules in females ovariectomized at the age of 1 month was much higher than that in intact females of the same age. These results showed that the ovaries exerted a suppressive effect on the development of adenomatous nodules. To determine the time from which the ovaries exert this suppressive effect, females were ovariectomized at 4, 6, 8, and 10 months of age, and the incidences of adenomatous nodules were compared at 10 and 12 months of age. Delayed ovariectomy after 8 months of age did decrease the incidence of adenomatous nodules at 10 and 12 months of age, but ovariectomy after 4 and 6 months of age did not. When the incidence of adenomatous nodules in females ovariectomized at 10 months of age was examined over the subsequent 6 months, it became significantly higher after 14 months of age compared with that in intact females. The results show that the ovariectomy has the promoting effect on the development of adenomatous nodules in the liver induced by 3'-Me-DAB after 6 months of age.

Aging↗

PubMed1992

Enhancement of dopaminergic agonist bromocriptine of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effects of the dopamine agonist 2-bromo-alpha-ergocryptine methanesulfonate (bromocriptine) on the incidence, number and histology of gastric cancer induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were investigated in Wistar rats. Rats were given 1 or 2 mg kg-1 body weight of bromocriptine subcutaneously every other day in depot form after 25 weeks of oral treatment with MNNG. Prolonged administration of bromocriptine at both dosages every other day resulted in a significant increase in the incidence and number of gastric cancers of the glandular stomach by week 52. Bromocriptine treatment did not influence the histological type of gastric cancer, but caused a significant increase in the labelling index of epithelial cells of the antrum. These findings indicate that the dopamine agonist bromocriptine promotes gastric carcinogenesis, and that this effect may be related to its effect in increasing proliferation of epithelial cells in the antral mucosa.

Adenocarcinoma↗

PubMed1992

Effect of treatment with cisapride alone or in combination with domperidone on gastric emptying and gastrointestinal symptoms in dyspeptic patients.

The effects on gastric emptying and gastrointestinal symptoms of treatment with cisapride alone and in combination with domperidone were investigated in 25 patients with chronic idiopathic dyspepsia. In a double-blind study, 9 patients were randomly assigned to receive cisapride 2.5 mg three times daily, and 8 patients to receive placebo. After 7 days of treatment, gastric emptying was significantly accelerated and the score of gastrointestinal symptoms was significantly reduced in patients treated with cisapride. Placebo treatment had no significant effect. A randomized, double-blind crossover study of 8 patients compared the effects of combined treatment with cisapride 2.5 mg plus domperidone 10 mg three times daily for 7 days against the effects of cisapride plus placebo. Administration of cisapride plus domperidone gave significantly higher gastric emptying and lower gastrointestinal symptoms than cisapride plus placebo.

Chronic Disease↗

PubMed1992

Effect of gamma-butyrolactone on baclofen inhibition of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effect of gamma-butyrolactone (GBL) on inhibition by baclofen of gastric carcinogenesis was investigated in Wistar rats. In week 52, baclofen significantly decreased the incidence of gastric cancers. Concomitant treatment with GBL significantly increased gastric acid secretion but had no influence on the inhibition by baclofen of gastric carcinogenesis. This finding suggest that GBL significantly increased the sensitivity of gamma-aminobutyric acid (GABA) receptor to GABA mimetics in gastric acid secretion but not in the inhibitory effect of gastric carcinogenesis.

4-Butyrolactone↗

PubMed1992

Attenuation by the GABA receptor agonist baclofen of experimental carcinogenesis in rat colon by azoxymethane.

The effects of the gamma-amino-n-butyric acid (GABA)A receptor agonist muscimol, and the GABAB receptor agonist baclofen, on colon carcinogenesis induced by azoxymethane in Wistar rats were tested. Administration of either muscimol or baclofen had no influence on the incidence of colon tumors at week 30. However, almost all the colon tumors that developed in rats treated with baclofen were adenomas, whereas in the control group the tumors were mainly adenocarcinomas. In contrast, administration of muscimol did not affect the histological types of the colon tumors. These findings indicate that baclofen inhibits the growth of colon tumors via the GABAB receptor.

Adenocarcinoma↗

PubMed1992

Enhancement by methionine- and leucine-enkephalin of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effects of the opioid receptor agonists methionine-enkephalin (Met-ENK) and leucine-enkephalin (Leu-ENK) on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine were investigated in Wistar rats. After 25 weeks of oral treatment with the carcinogen, the rats received subcutaneous injections of Met-ENK (20 micrograms/kg) or Leu-ENK (20 micrograms/kg) once every 2 days. The prolonged administrations of Met-ENK and Leu-ENK significantly increased the incidence of gastric cancers in week 52. Treatments with these opioid receptor agonists significantly increased the labeling index of the antral mucosa. These findings indicate that opioids enhance gastric carcinogenesis and suggest that their effects may be related to their influence on increasing proliferation of the antral epithelial cells.

Animals↗

PubMed1992

[Evaluation of chromo-endoscopy for diagnosis of histological repair of gastric ulcer].

The chromoendoscopic features of healed gastric ulcers were investigated by the methylene blue test. Histological repair of healed ulcers was graded as either Ul3 (incompletely healed) or Ul4 (completely healed). Endoscopically, the Ul4 scar was observed as a flat granular area without any depression, and sometimes associated with redness, the Ul3 scar was observed as a distinct depression in the surrounding normal mucosal surface, and usually associated with homogenous redness. Follow-up studies of patients with Ul4 and Ul3 lesions showed that recurrence was significantly rare in patients with the Ul4 lesion than in patients with the Ul3 lesions. These findings indicate that healing of gastric ulcers should be defined endoscopically as crater disappearance. At 8 weeks after treatment with omepral, most of the ulcers were healed, but judged a as Ul3 scar.

Adenosine Triphosphatases↗

PubMed1991

Inhibition by the dopamine antagonist haloperidol of experimental carcinogenesis induced by azoxymethane in rat colon.

The effects of the dopamine agonist bromocriptine and antagonist haloperidol on the incidence and histology of colon tumors induced by azoxymethane and on the labeling index of colon mucosa were investigated in Wistar rats. Rats received weekly s.c. injections of 7.4 mg/kg of body weight azoxymethane for 10 weeks and s.c. injections of 2 mg/kg of body weight bromocriptine or 2 mg/kg of body weight haloperidol, in depot form, every other day until the end of the experiment in week 30. Administration of haloperidol resulted in a significant decrease in the incidence of colon tumors. It also caused a significant decrease in the incidence of adenocarcinomas, with 75% of the tumors being adenomas, and in the labeling index of the colon epithelial cells. In contrast, bromocriptine had no influence on the incidence or histology of colon tumors or the labeling index of the colon mucosa. These findings indicate that the dopamine antagonist haloperidol inhibits colon carcinogenesis and that this effect may be related to its effect in decreasing the proliferation of colon epithelial cells.

Adenocarcinoma↗

PubMed1991

Inhibition by retinoic acid of hepatocarcinogenesis induced by N-nitrosomorpholine and of expression of myc oncogene protein in Sprague-Dawley rats.

The effects of all-trans-retinoic acid (RA) on hepato-carcinogenesis induced by N-nitrosomorpholine (NNM) and on the expression of myc p110 proteins were investigated in male Sprague-Dawley rats. Rats received i.m. injections of RA twice a week and, from the beginning of the experiment, were given drinking water containing NNM for 8 weeks. Pre-neoplastic and neoplastic lesions staining positively for gamma-glutamyl transpeptidase (GGT), glutathione-S-transferase placental type (GST-P) or myc p110 protein were examined histochemically. At week 18, quantitative histological analysis showed that prolonged administration of RA resulted in a significant reduction in the number, size and volume of GGT-positive and GST-P-positive hepatic lesions. Administration of RA also caused a significant increase in the proportion of myc p110-negative lesions to the total pre-neoplastic lesions observed. Myc p110-negative lesions had a significantly lower mitotic index than myc p110-positive lesions. These findings indicate that RA inhibits hepatocarcinogenesis and suggest that this effect may be related to its influence in reducing the expression of myc gene proteins and its subsequent inhibition of cell proliferation in pre-neoplastic lesions.

Animals↗

PubMed1991

Roles of ovaries and testes in hepatocellular tumorigenesis induced in mice by 3'-methyl-4-dimethylaminoazobenzene.

The roles of gonads in tumorigenesis induced in mouse liver by 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) were investigated. C57BL/6 x DS-F1 mice which were 10, 12, 14, 16 and 18 days old were treated i.p. with 3'-Me-DAB. Nodular lesions induced in the liver were classified into adenomatous nodules and hepatocellular carcinomas. Adenomatous nodules were composed of a mixture of eosinophilic, basophilic, vacuolated and foamy hepatocytes in various proportions and compressed the adjacent parenchyma. These adenomatous nodules were of monoclonal origin. Carcinomas had a trabecular structure. The incidence, numbers per mouse and areas of adenomatous nodules and carcinomas in male and female mice aged 16-64 weeks were compared. Adenomatous nodules were first detected in males and females aged 24 and 52 weeks, respectively, and their incidences were much higher in males than in females of the same age. The number of adenomatous nodules per mouse and their size were also higher in males. The first carcinoma was found in a 52-week-old male, but no carcinomas were found in females even at 64 weeks of age. The effects of castration 23 days after birth on the appearance of nodular lesions in the livers of 32- to 64-week-old mice were examined. Castration of males did not affect the incidence of adenomatous nodules, but reduced the incidence of carcinomas. It also decreased the number of adenomatous nodules per mouse. Castration of females reduced the time before appearance of adenomatous nodules and increased their incidence, number per mouse, and area. A carcinoma appeared in a 64-week-old castrated female, but no similar lesion was found in intact females of the same age. These results indicate that tumorigenesis induced in mouse liver by 3'-Me-DAB is enhanced by the testes and suppressed by the ovaries.

Adenoma↗