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Biomedical subjects

M Ichii

Publications and source records attributed to M Ichii.

At least 37 records · Page 2Linked to original sources
PubMed1991

Protective effect by potassium chloride against gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in spontaneously hypertensive rats.

The effects of oral potassium supplementation on the enhanced induction of gastric carcinogenesis by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in spontaneously hypertensive rats (SHR), and the norepinephrine concentration in their gastric wall were investigated. The SHR and normotensive Wistar Kyoto rats (WKY) as controls were given a solution of the carcinogen for 25 weeks and then 1% KCl solution or tap water to drink. In Week 52, the incidence of gastric cancers and their number per rat and the norepinephrine concentration in the gastric wall were significantly greater in SHR than in WKY. Prolonged oral treatment of SHR with potassium significantly reduced the incidence of gastric cancers and their number per rat, as well as the blood pressure and the norepinephrine concentration in the antral portion of the gastric wall. These findings indicate that prolonged treatment with KCl attenuated the enhancement of gastric carcinogenesis by MNNG in SHR.

Animals↗
PubMed1990

Attenuating effect of bromocriptine on cysteamine anticarcinogenesis of stomach cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine.

The effect of bromocriptine on inhibition by cysteamine of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine was investigated in inbred Wistar rats. After 25 weeks of p.o. treatment with N-methyl-N'-nitro-N-nitrosoguanidine, rats were given injections every other day: cysteamine (50 mg/kg body weight); cysteamine (50 mg/kg body weight) plus bromocriptine (0.5 or 0.25 mg/kg body weight); or bromocriptine (0.5 or 0.25 mg/kg body weight). In week 52, the group treated with cysteamine showed a significantly decreased incidence of gastric cancers. Concomitant treatment with bromocriptine at 0.5 but not at 0.25 mg/kg body weight significantly attenuated the inhibitory effect of cysteamine on gastric carcinogenesis. Administration of bromocriptine alone at either dosage had no influence on gastric carcinogenesis. The labeling index of the antral mucosa was significantly reduced in rats treated with cysteamine and significantly higher in those treated concomitantly with bromocriptine at 0.5 mg/kg body weight than in those treated with cysteamine alone. These findings indicate that cysteamine suppressed gastric carcinogenesis and that bromocriptine at high dosage attenuated this inhibition. These findings also suggest that dopamine is involved in the mechanism of inhibition of gastric carcinogenesis by cysteamine.

Animals↗
PubMed1990

Inhibition by gamma-amino-n-butyric acid and baclofen of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effect of gamma-amino-n-butyric acid (GABA), the GABA(A) receptor agonist muscimol (5-aminomethyl-3-hydroxyisoxazole), and the GABA(B) receptor agonist baclofen [4-amino-3-(4-chlorophenyl)butanoic acid] on the incidence and number of gastric cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine was investigated in Wistar rats. Rats received alternate-day i.p. injections of 500 or 1000 mg/kg of body weight GABA, 0.25 or 0.5 mg/kg of body weight muscimol, or 4 or 8 mg/kg of body weight baclofen after 25 wk of p.o. treatment with the carcinogen. Prolonged administration of GABA at 1000 mg/kg of body weight, but not at 500 mg/kg of body weight, and of baclofen at 4 and 8 mg/kg of body weight significantly decreased the incidence and number of gastric cancers of the glandular stomach in Wk 52, but long-term muscimol administration had no influence. Histologically, GABA at the high dosage and baclofen at both dosages significantly decreased the labeling index of the antral mucosa and significantly increased the serum gastrin level. Furthermore, baclofen at both dosages significantly decreased antral pH and significantly increased gastric acid secretion. These findings indicate that GABA inhibits gastric carcinogenesis via the GABAB receptor and that this effect may be related to its effect in decreasing the proliferation of antral mucosa.

Animals↗
PubMed1989

Promotion by bombesin of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effects of bombesin on the incidence, number, histological type, and depth of involvement of gastric cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were investigated in male Wistar rats. Rats received alternate-day s.c. administration of 20 or 40 micrograms/kg body weight of bombesin in depot form after p.o. treatment with the carcinogen for 25 weeks. Prolonged administration of bombesin at 40 micrograms/kg led to a significant increase in the incidence and number per rat of gastric cancers of the glandular stomach at Week 52. In rats that had received alternate-day injections of 20 micrograms/kg of bombesin, the number of gastric cancers per rat, but not the incidence of cancer, was significantly more than in untreated rats. However, bombesin at both dosages did not affect the histological appearance of the lesions or their depth of involvement. At Weeks 30 and 52, norepinephrine concentrations in the fundic and antral portion of the gastric walls and labeling indices in the antral and fundic mucosae were significantly higher in rats treated with bombesin at both dosages than in untreated rats. These findings indicate that bombesin enhances gastric carcinogenesis after administration of N-methyl-N'-nitro-N-nitrosoguanidine is stopped and that this effect may be related to its effects in increasing tissue norepinephrine concentrations in the stomach wall and increasing cell proliferation in the gastric mucosa.

Animals↗
PubMed1989

Diagnosis of gastric cancers with fluorescein-labeled monoclonal antibodies to carcinoembryonic antigen.

Forty gastric adenocarcinomas in 30 resected stomachs were examined by an endoscopic immunofluorescent technique using fluorescein isothiocyanate (FITC)-labeled antibodies to carcinoembryonic antigen (CEA). Fluorescence images of the tumors were obtained with a newly developed endoscopic television system for detecting faint fluorescence. Computer-assisted processing was used to enhance the detection and localization of the tumors visualized by the immunofluorescent technique. Twenty seven (90%) of 30 tumors showed positive fluorescence after treatment with FITC-labeled antibodies for 60 minutes, whereas only two (40%) of five cancers could be detected by the immunofluorescent technique after treatment with antibodies for less than 60 minutes. There was no significant relationship between positive fluorescence and the gross and histological types or the stages of the tumors. In contrast, no positive fluorescence could be demonstrated in cases of benign gastric lesions or after pretreatment with FITC-labeled alpha-fetoprotein. This study therefore suggests that the immunofluorescent technique using FITC-labeled anti-CEA antibodies can be useful in detecting the early stages of gastric cancer.

Adenocarcinoma↗
PubMed1988

[Indications for and limitations of HpD photodynamic therapy for esophageal cancer and gastric cancer].

HpD photodynamic therapy (PDT) was performed on 4 patients with superficial esophageal cancer, 20 patients with 22 early gastric cancer lesions and one patient with advanced gastric cancer. About 50 h before irradiation, 3 mg/kg of HpD or 1.3-2.5 mg/kg of Photofrin II was injected intravenously. The entire lesion including a 5-mm border of normal surrounding mucosa, was irradiated with an argon dye laser at 630nm wavelength with an output of 100-400mW at the tip of the fiber. Complete response (CR) to HpD-PDT was obtained in 2 of 2 mucosal esophageal cancers, and one of 2 submucosal lesions, totalling 3 of 4, and in 13 of 13 mucosal gastric cancers and 7 of 9 submucosal lesions totalling 20 of 22. The depths of cancer involvement were determined endoscopically. In Borrmann 1 lesion with muscularis externa involvement, in spite of two trials with HpD-PDT, only partial response (PR) was obtained. Tumor laser dose had to be more than 90 J/cm2, and in several cases combined hot biopsy with electrodiathermy and/or repeated HpD-PDT was needed to obtain CR. HpD-PDT is indicated for superficial esophageal cancer and depressed and/or assembled protuberant-type of early gastric cancer with poor risk.

Aged↗
PubMed1986

Values of carcinoembryonic antigen, elastase 1, and carbohydrate antigen determinant in aspirated pancreatic cystic fluid in the diagnosis of cysts of the pancreas.

The levels of carcinoembryonic antigen (CEA), elastase 1, and carbohydrate antigen determinant (CA 19-9) in the pancreatic cystic fluid and the serum from five patients with cystadenocarcinoma of the pancreas, one patient with retention cyst due to pancreatic carcinoma, three patients with cystadenoma, and eight patients with benign pseudocyst accompanying or following pancreatitis, were determined by immunoassay technique. Fluid from pancreatic cysts was obtained by ultrasonically-guided percutaneous fine-needle aspiration biopsy. The specimens were centrifuged and the supernatant was used for the measurement of CEA, elastase 1, and CA 19-9, while the cell pellet was examined cytologically. The levels of CEA in the aspirated fluid were significantly higher in patients with malignant cysts of the pancreas than in those with benign cystadenomas and pseudocysts. In contrast, the levels of elastase 1 were significantly lower in patients with malignant cysts than in those with benign pancreatic cysts. Although the levels of CA 19-9 were significantly higher in patients with malignant cysts than in those with pseudocysts, the overlap between the values of patients with malignant and benign pancreatic cysts is too great. The serum CA 19-9 was most useful, however, to distinguish an individual patient with malignant cysts of the pancreas from those with benign pancreatic cyst, since there were no significant differences between the levels of serum CEA and elastase 1 in patients with malignant and benign pancreatic cysts. Correct diagnoses were made cytologically in 4 (66.7%) of 6 patients with malignant cysts. In two patients with malignant cyst, in whom no cancer cells were detectable in the aspirated materials, levels of CEA were abnormally high, but high levels of elastase 1 did not occur. Therefore, the combined measurement of CEA and elastase 1 in the aspirated cystic fluid of the pancreas could be used as an aid in diagnosis of malignant cysts of the pancreas.

Antigens, Neoplasm↗
PubMed1986

Inhibitory effects of tetragastrin and histamine on carcinogenesis in the small intestines of W rats by N-methyl-N'-nitro-N-nitrosoguanidine.

The effects of tetragastrin and histamine on the incidence and histology of tumors induced in the small intestine by N-methyl-N'-nitro-N-nitrosoguanidine [(MNNG) CAS: 70-25-7] were investigated in male W rats. Animals were given MNNG at 150 micrograms/ml in their drinking water for 25 weeks and then 300 micrograms tetragastrin or 4 mg histamine dihydrochloride sc per day in depot form. Administration of tetragastrin or histamine after MNNG treatment resulted in a significant increase in gastric acid secretion and a significant reduction in the incidence of tumors in the duodenum; however, only histamine decreased the incidence of tumors in the jejunum. Histologically, the tumors induced in the small intestine were mostly adenocarcinomas, and their histologic type was not affected by either tetragastrin or histamine.

Adenocarcinoma↗
PubMed1986

Effect of tetragastrin on the colonic mucosa of rats during intrarectal administration of N-methyl-N'-nitro-N-nitrosoguanidine.

The effects of the C-terminal tetrapeptide of gastrin, tetragastrin, on the colonic mucosa on Days 15 and 25 during intrarectal administration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and its effects on the incidences of colonic tumors in experimental Wk 20 and 35 were investigated in Wistar rats. Administration of tetragastrin in depot form during instillation of MNNG resulted in significant decreases in the incidences of mucosal erosions, ulcerations, and atypical regenerative glandular hyperplasias in the colonic mucosa, most of these lesions being greater in the distal half of the colon. Administration of tetragastrin also significantly decreased the incidences and/or numbers of colonic tumors in Wk 20 and 35. The distribution of colonic tumors induced in Wk 20 and 35 corresponded well to those of erosions, ulcerations, and atypical regenerative glandular hyperplasias induced during the administration of MNNG. These findings suggest that the effect of tetragastrin in decreasing the incidences of erosions, ulcerations, and atypical regenerative glandular hyperplasias in the colonic mucosa during instillation of MNNG is related to its effect in reducing the development of colonic tumors.

Animals↗
PubMed1985

Values of CA 19-9 in the serum, pure pancreatic juice, and aspirated pancreatic material in the diagnosis of malignant pancreatic tumor.

The diagnostic accuracy of the measurement of CA 19-9 in the serum, pure pancreatic juice, and aspirated pancreatic fluid in the diagnosis of pancreatic tumors was assessed in 32 patients with malignant pancreatic tumors and 19 patients with pancreatitis. Pure pancreatic juice was collected from the pancreatic duct by endoscopic cannulation with a duodenofiberscope after intravenous administration of secretin. Pancreatic material was obtained by percutaneous fine-needle aspiration biopsy under ultrasonic guidance. Abnormally high CA 19-9 levels in the serum were significantly more frequent in patients with malignant pancreatic tumors than in those with pancreatitis: they were elevated in 71.9% of the patients with pancreatic tumors. High CA 19-9 levels were found primarily in patients with a tumor of the head of the pancreas, in those with a tumor greater than 3 cm in its greatest diameter, and in those with an unresectable cancer. Only 57.1% of seven patients with a tumor of less than 3 cm in its greatest diameter showed an increase in CA 19-9 level. The CA 19-9 levels in pure pancreatic juice were significantly higher in patients with pancreatic tumors than in patients with pancreatitis without pancreatic stone. However, it was not useful for differentiating pancreatic tumors from pancreatitis with pancreatolithiasis. The CA 19-9 level in pancreatic materials obtained by aspiration biopsy was significantly higher in patients with malignant pancreatic tumors than in those with pancreatitis. Eight patients (80%) with pancreatic tumors had values above 1000 U/ml, whereas all five patients with pancreatitis had values of less than 30 U/ml. Although CA 19-9 levels in pancreatic materials was useful only when cytologic examination did not provide any evidence of malignancy, the combination of the CA 19-9 assay and the cytologic study of specimens obtained by percutaneous fine-needle aspiration biopsy of the pancreas increased the diagnostic rate to 100%.

Adult↗
PubMed1985

Gastrin has no promoting effect on chemically induced colonic tumors in Wistar rats.

The effects of prolonged administration of tetragastrin from the beginning of intrarectal instillation of 1 ml of 0.25% N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and after MNNG-treatment on the incidence and histology of colonic tumors were compared in inbred Wistar rats. In week 35 prolonged administration of testragastrin in depot form from the beginning of MNNG-treatment resulted in a significant reduction in the incidence of colonic tumors and a significant increase in the incidence of mucinous adenocarcinoma, unlike the well-differentiated adenocarcinoma produced in controls without gastrin. In contrast, prolonged administration of tetragastrin after MNNG-treatment had little or no influence on the incidence, size or histology of colonic tumors. Thus tetragastrin had no promoting effect on colonic tumors.

Adenocarcinoma↗
PubMed1985

Chromoendoscopic observations on extension and development of fundal gastritis and intestinal metaplasia.

The development and extension of fundal gastritis and intestinal metaplasia were investigated by the endoscopic Congo red-methylene blue test in 44 healthy subjects, 106 patients with gastric ulcer, and 26 patients with gastric polyp. Follow-up chromoendoscopic examinations were made an average of 3.4 yr (range 1-10 yr) after the initial endoscopic assessment. Fundal gastritis and intestinal metaplasia developed or became more extensive with time in only 3 (6.8%) and 2 (4.5%) healthy subjects, respectively. In patients with gastric ulcer and in those with gastric polyp, fundal gastritis and intestinal metaplasia developed or extended significantly more frequently and more rapidly than in healthy subjects. Fundal gastritis and intestinal metaplasia developed or became more extensive, respectively, in 26 (24.5%) and 23 (21.7%) patients with gastric ulcer and in 10 (38.5%) and 10 (38.5%) patients with gastric polyp. Fundal gastritis and intestinal metaplasia extended with time mainly in an upward direction.

Adult↗
PubMed1985

Effect of a chemically defined diet in liquid form on colon carcinogenesis in rats.

The effects of ad libitum feeding of a chemically defined diet in liquid form on the incidence and histology of colon cancer induced by 10 weekly sc injections of 7.4 mg/kg of azoxymethane [(AOM) CAS: 25843-45-2] were investigated in W-rats. The chemically defined diet was adjusted once every 24 hours from 4 weeks before injection of the carcinogen to the end of the experiment at week 40. Oral administration of the defined diet resulted in significant increase in the incidence of colon cancer at week 40. Histologic examination showed that unlike adenocarcinomas with high mucin-producing activity, which were common in rats on pellet diet, most of the adenocarcinomas that developed in rats fed on defined diet were highly or well differentiated, with a typical glandular pattern. Administration of the chemically defined diet also resulted in marked colon mucosal hypoplasia and reduced gastrin levels in the serum at weeks 4 and 40.

Adenocarcinoma↗
PubMed1985

Promotion by vagotomy of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effects of truncal vagotomy after administration of N-methyl-N'-nitro-N-nitrosoguanidine on the incidence and number of gastric carcinomas and gastric acid secretion, gastrin secretion, antral pH, and duodenal reflux were investigated in inbred Wistar rats. Rats were subjected to truncal vagotomy after N-methyl-N'-nitro-N-nitrosoguanidine treatment. Vagotomy significantly increased the incidence and number of adenocarcinomas of the glandular stomach. It also resulted in significantly more atypical glandular hyperplasias, which are precursors of gastric cancer. Furthermore, it caused a decrease in gastric secretion and an increase in mucosal pH in the antrum but did not increase duodenal reflux. These findings indicate that vagotomy has a promoting effect on the development of gastric cancers. The reduced gastric acid secretion, but not duodenal reflux, may be related to this increased incidence of gastric cancer.

Animals↗
PubMed1984

Destruction of implanted gastric tumors in rats by acridine orange photoactivation with an argon laser.

The phototoxicity of acridine orange and argon laser irradiation on Walker carcinosarcoma 256 stomach tumors was studied. Wistar strain rats bearing stomach tumors 4-6 mm in diameter 5-10 days after their implantation were injected intraperitoneally with 40 mg/kg of acridine orange 2 hr before irradiation. Then the forestomach was opened and the tumors were exposed to the argon laser at 488 nm at an intensity of 15 mW/cm2 for 20 min. Tumors in rats treated with acridine orange were brightly fluorescent during irradiation. No marked temperature rise was detected during irradiation. Argon irradiation significantly prolonged the survival of rats treated with acridine orange. Histologically, complete or partial tumor necrosis was observed, with sparing of surrounding mucosa, in rats treated by the combination therapy. Phase-contrast and electron microscopy showed that cytotoxicity was mediated by changes in the cell, nuclear and lysosomal membranes. Neither the dye nor laser alone had any effect.

Acridine Orange↗
PubMed1984

Values of serum carcinoembryonic antigen and elastase 1 in diagnosis of pancreatic carcinoma.

Carcinoembryonic antigen (CEA) and elastase 1 in the serum were determined by enzyme immunoassay and radioimmunoassay, respectively, in 224 healthy subjects, 49 patients with pancreatitis, 53 patients with pancreatic carcinoma and 129 patients with cancer in other organs. The CEA concentrations in the serum were significantly higher in patients with pancreatic carcinoma than in those with pancreatitis, but this concentration was not a satisfactory indicator of pancreatic carcinoma localised to allow irradication by resection as it was raised in only 47% of the patients. High CEA concentrations were also slightly, but not significantly, more frequent in patients with cancer of the pancreatic body or tail, and unresectable cancer or cancer of more than 6.0 cm in longest diameter than in those with cancer of the pancreatic head, resectable cancer or cancer of less than 6.0 cm diameter. Serum elastase 1 was raised in only 42% of the patients with pancreatic carcinoma and could not be used to distinguish patients with pancreatic carcinoma from those with pancreatitis. In contrast with CEA, however, its concentration was abnormally high significantly more frequently in patients with cancer of less than 6.0 cm in longest diameter than in those with larger tumours. It was also raised slightly, but not significantly, more frequently in those with cancer of the pancreatic head and in patients with resectable cancer than in those with unresectable cancer. A combination of these two tests raised the diagnostic rate of pancreatic carcinoma to 77% without a remarkable decrease in the specificity for pancreatic carcinoma. In particular, it raised the diagnostic rates of cases of cancer of the pancreatic head, resectable cancer and cancers of less than 3.0 cm and 3.0-6.0 cm in longest diameter. Therefore, a combination of measurements of CEA and elastase 1 in the serum is very useful for early detection of pancreatic carcinoma.

Adult↗
PubMed1984

Carcinoembryonic antigens in the pericardial fluid of patients with malignant pericarditis.

The diagnostic accuracy of measurement of carcinoembryonic antigen (CEA) and of analysis of the cytological characteristics of pericardial fluid was assessed in 10 patients with benign pericarditis and 7 patients with malignant pericarditis. The mean CEA levels of pericardial fluid specimens from patients with malignant pericarditis were significantly higher than those from patients with benign pericarditis. However, a high CEA level was not seen in a specimen of pericardial fluid which contained nonepithelial tumor cells. Positive cytological findings were obtained in specimens of pericardial fluid from 85.7% of the patients with malignant pericarditis. Correct diagnosis of malignancy was made by CEA assay alone or by cytological examination alone in 85.7% of the patients examined, while a combination of these methods raised the diagnostic rate to 100%.

Carcinoembryonic Antigen↗