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Biomedical subjects

T Sakata

Publications and source records attributed to T Sakata.

At least 487 records · Page 27Linked to original sources
PubMed1984

Hepatocellular carcinoma of small size.

Clinicopathological features of hepatocellular carcinoma (HCC) of small size, not larger than 5.0 cm in diameter, were studied in 11 patients with underlying cirrhosis. The presence of tumor was detected and confirmed by computed tomography (CT) and ultrasonography (US) during periodic imaging re-examinations of cirrhotic patients. The HCCs grew slowly up to a certain stage and formed satellite tumors that could not be visualized on CT image. Therefore, infusion hepatic angiography and/or transcatheter arterial embolization (TAE) are essential before undertaking a major operation.

Aged↗
PubMed1984

Primary carcinomas of urinary bladder diverticula.

Two cases of carcinoma arising from the urinary bladder diverticulum were found at autopsy. Both patients had hematuria as a chief complaint and were found to have a tumor mass in the bladder on cystoscopic examination. However, owing to various difficulties the tumors could not be diagnosed before death. Autopsy revealed that the tumors in both cases had arisen within diverticula and had grown into the orifice of the diverticula giving the appearance of ordinary bladder tumors. Histological examination showed that in Case 1, two carcinomas, a keratinizing squamous cell carcinoma and a transitional cell carcinoma, had developed separately in a diverticulum. This may be the first case report of two cancers in a bladder diverticulum. There were no metastases in this case. Case 2 had an undifferentiated carcinoma with metastases to many organs including the lung, liver, and lymph nodes.

Aged↗
PubMed1984

Modification of carcinogenesis by antioxidants and other compounds.

Studies were made on the effects of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), sodium L-ascorbate (SA), ethoxyquin (EQ) and acetaminophen (AAF) on the induction of neoplastic lesions in the liver, kidney or urinary bladder of rats initiated by N-ethyl-N-hydroxyethylnitrosamine (EHEN), diethylnitrosamine (DEN) or N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). The number and area of histochemical gamma-glutamyltranspeptidase-positive (gamma-GT+) foci per unit area of liver section in rats given BHA, BHT, EQ or AAP, but not SA, were significantly less than in rats given EHEN or DEN alone. Similarly, the number of hyperplastic nodules (HN) in groups given BHA or AAP and their area in groups given BHA, EQ or AAP were significantly less than in control groups. Induction of hepatocellular carcinoma (HCC) was also clearly inhibited by these three chemicals. In contrast, the incidence and quantitative values of preneoplastic lesions and renal cell adenoma in the group given EHEN were significantly increased in groups given BHA, EQ or AAP administration. For assesing the influence of BHA and BHT on urinary bladder carcinogenesis, rats received BHA or BHT after treatment with BBN. The incidences and the number per unit length of basement membrane of papilloma and carcinomas were significantly increased in rats given BHA. BHT also showed significant increase but values were less than with BHA. These results clearly demonstrated that BHA, BHT, EQ and AAP inhibit the development of gamma-GT+ foci, or HN and HCC, whereas BHA, EQ and AAP enhance the appearance of preneoplastic and neoplastic lesions in the kidney, BHA and BHT also enhancing urinary bladder carcinogenesis.

Acetaminophen↗
PubMed1984

Modulation of feeding by endogenous sugar acids acting as hunger or satiety factors.

Endogenous sugar acids, 3,4-dihydroxybutanoic acid (2-deoxytetronic acid, 2-DTA) and 2,4,5-trihydroxypentanoic acid (3-deoxypentonic acid, 3-DPA), have been identified in the serum of fasted rats. Effects of these sugar acids on rat feeding behavior and neuron activity were investigated. Injections of 2-DTA (2.5 mumol) into the third cerebral ventricle of chronic rats suppressed food intake and single-neuron activity in the lateral hypothalamic area (LHA). Food consumption was reduced for 24 h, even in 72-h food-deprived rats. The same amounts of 3-DPA elicited feeding and increased LHA single-neuron activity with latencies of 6-8 min. Electrophoretically applied 2-DTA significantly and specifically suppressed activity of glucose-sensitive neurons in the LHA, whereas 3-DPA facilitated the activity. Nonglucose-sensitive LHA neurons were not affected by these sugar acids. The high correlation between modulation of feeding behavior and changes in LHA neuron activity after injection of these sugar acids suggested that 2-DTA may act as an endogenous satiety substance and 3-DPA as a hunger substance. The effects may be mediated through glucose-sensitive neurons in the LHA.

Animals↗
PubMed1984

Hypersensitivity pneumonitis induced by Trichosporon cutaneum.

We isolated Trichosporon cutaneum from the houses of patients with hypersensitivity pneumonitis and investigated its possible role as an etiologic agent in 21 cases of the disease. A high titer of anti-T. cutaneum antibody was observed in serum samples from 20 (95.2%) of the 21 patients, but only a low titer was found in less than 9% of the control serum samples. Anti-Cryptococcus neoformans antibody was also observed in the patients' serum samples, but it appeared, in most samples, to be a cross-reaction to T. cutaneum antigen. This was because the anti-C. neoformans antibody was completely absorbed with T. cutaneum, but the anti-T. cutaneum antibody was only partly absorbed with C. neoformans. Besides, no C. neoformans was isolated from the patients' environment. A bronchoprovocation test with T. cutaneum was done on one patient, with a positive result. We also found T. cutaneum in bird droppings containing nutrients for this organism. To our knowledge, this is the first report on hypersensitivity pneumonitis induced by T. cutaneum.

Adult↗
PubMed1984

A long-term follow-up study of valve replacements.

We have studied the long-term results of valve replacement operations in 591 patients, one year or more after surgery, and also analyzed rates of social return in 523 patients (response rate, 86.1 per cent) by questionnaire. Of the 591 patients, 81 patients suffered early death (mortality rate, 13.7 per cent) and 41 patients late death (mortality rate, 6.9 per cent). The causes of the latter were left atrial thrombus (18 cases), heart failure (10 cases), artificial valve failure (five cases), renal failure (two cases) and hepatic insufficiency, infection and accident (one case each). Second replacement was performed in 18 patients (3.0 per cent), 49 months on average from the first operation. The survival rate at the 12th postoperative year was 68.7 per cent. The overall rate of social return after valve replacement was 64.8 per cent, including 74.8 per cent for mitral valve replacement, 54.3 per cent for aortic and 51.5 for multivalvular. The rate of social return has been improved to 76.4 per cent in the last five years.

Aortic Valve↗
PubMed1984

Effects of carbon tetrachloride and azathioprine on diethylnitrosamine and N-2-fluorenylacetamide-induced hyperplastic liver nodule and hepatocellular carcinoma.

Effects of carbon tetrachloride (CCl4) and azathioprine (AZP) on the evolution of hyperplastic liver nodules and foci and hepatocellular carcinoma (HCC) were tested in short- and long-term in vivo experiments. In diethylnitrosamine (DEN)-treated rats, which were fed a N-2-fluorenylacetamide (FAA)-containing diet and additionally treated with repeated CCl4 injections, gamma-glutamyl transpeptidase (gamma-GTP)-positive hyperplastic nodules were markedly developed in the 8th week of the experiment. However, their number and area in liver sections were remarkably small in DEN-treated rats fed a diet containing both FAA and AZP. Increased area of gamma-GTP-positive foci was also observed in the 12th week in DEN-injected rats fed a choline-devoid died alone or treated with repeated doses of CCl4 alone. Hepatocellular carcinoma in DEN-injected rats treated with both FAA and CCl4 was first detected in the 21st week, and the incidence up to the 36th week was very high. However, no hepatocellular carcinoma developed in DEN-injected rats treated with both FAA and AZP. The increased activity of liver aniline hydroxylase observed 12 h after the administration of FAA, AZP or DEN alone was not observed when AZP was administered simultaneously with FAA to DEN-injected rats. The mechanisms of the effects of CCl4 and AZP on hepatocarcinogenesis are discussed with special reference to drug interaction.

2-Acetylaminofluorene↗
PubMed1984

[Changes in meal patterns and endogenous chemical determinants related to food intake following intra-ventricle III infusion of mazindol].

To clarify suppressive effects of mazindol on food intake in rats, changes in body weight, meal patterns as well as 24-hr food intake, and endogenous chemical substances were investigated following the intra-ventricle III infusion of 0.03 mumole mazindol. Experiments were carried out under the condition of a 12: 12 light-dark cycle (light: 0800-2000 hr). Mazindol decreased food intake as well as body weight after a 12 hr starvation. Reduced food consumption was observed during 12 hr following the injection. Weight reduction, however, lasted over all 3-tested days. When food was available ad. lib., mazindol decreased meal size during the 4 hr after injection and prolonged postprandial intermeal interval during the 4 hr period starting 2 hr after the injection. The infusion of mazindol also produced relative hyperglycemia and decreased free fatty acids, which was not accompanied with hyperinsulinemia. These findings, together with other reports, indicates that mazindol, unlike amphetamine and fenfluramine, possesses inhibitory actions on the hypothalamic feeding center.

Animals↗
PubMed1984

Changes in meal pattern and endogenous feeding related substances following mazindol administration.

In order to ascertain direct central anorectic actions of mazindol (MZD), subtle changes in meal patterns and endogenous feeding related chemical substances were examined in rats following intra-third ventricle injection of 0.03 mumole MZD. In ad lib feeding, MZD decreased meal size and prolonged postprandial intermeal interval during a 4 hr period starting 2 hr after injection. The magnitude of anorectic actions of MZD was depressed by hunger. Although the action of MZD is short in duration, long duration anorexia was achieved by chronic infusion for 8 days. Infusion of MZD starting at 5:50 p.m. decreased plasma insulin, leaving glucose and glucagon unaffected, although no change in plasma glucose or insulin was observed following injection at 11:30 a.m. These findings, together with other reports, can be explained by MZD's direct effects on the hypothalamic hunger and satiation centers.

Animals↗
PubMed1984

[Effects of estrogen, progesterone and androgen on autoradiograms of the immature rat uterus].

Endometrial cancer is more frequent in patients at a postmenopausal age, when the ovarian secretion of androgens instead of estrogens seems to be relatively increased. In clinical or experimental medicine, progesterones are widely used for the treatment of endometrial cancer, probably because they have an antiestrogenic action and cause differentiation of cancer cells from the proliferative phase. The effects of testosterone(T), progesterone(P), and/or 17 beta-estradiol(E) on the incorporation of 3H-thymidine in autoradiograms were investigated in immature rats. The autoradiogram revealed many grains due to 3H-thymidine in the endometrial epithelium, stroma, and the myometrium in the immature rat 30 hours after E-injection. T alone markedly induced the DNA synthesis in the stroma and the myometrium, but not in the epithelium. T displayed a synergistic interaction with E in both the stroma and the myometrium with a slight increase in thymidine incorporation into the epithelium. P alone induced DNA synthesis in the stroma and the myometrium. Simultaneous injection of E and P also produced the same result as that when P alone was injected. P markedly inhibited DNA synthesis due to E in the epithelium. Autoradiograms of the immature rat uterus provide basic support for the rationality of P therapy for cancer or adenomatous hyperplasia of the endometrium.

Androgens↗
PubMed1984

Summation and synergism in the promotion of urinary bladder carcinogenesis initiated by N-butyl-N-(4-hydroxybutyl)-nitrosamine in F344 rats.

Summation and synergism in the effects of three tumor promoters on urinary bladder carcinogenesis initiated by a 4-week treatment with 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in male F344 rats were examined. In experiment 1, the sequential administration of sodium saccharin (SS, 5.0%), DL-tryptophan (Tr, 2.0%) and sodium L-ascorbate (SA, 5.0%) in the diet, each for 10 weeks, significantly increased the incidence and the number of bladder tumors over that observed after SS alone or SS followed by Tr. In experiment 2, the simultaneous dietary administration of 2.5% SA, 1.0% butylated hydroxyanisole and 0.01% allopurinol for 32 weeks significantly increased the yield of bladder tumors. Paired combinations of promoters or each of the promoters administered alone were associated with a less pronounced promotive effect than when all three were combined. Thus, it is evident from the results of the present investigation that whatever the mechanisms underlying promotion by the different agents, they are capable of working in an additive fashion, under conditions of summation (consecutive administration) or synergism (simultaneous administration).

Allopurinol↗
PubMed1983

Microdisc-electrophoretic study of deoxyribonucleases in cow snout epidermis.

Acid and neutral deoxyribonucleases (DNases) of the cow snout epidermis were investigated by the microdisc-electrophoresis of polyacrylamide gels containing highly polymerized DNA and by isoelectric focusing techniques. The nucleases were characterized with respect to their pH optimum. An acid DNase at pH 5.0 was detected as a single distinct band after the electrophoretic separation. After isoelectric focussing also, only one acid DNase activity with an isoelectric point (IP) of 6.2 was detectable. Neutral DNases at pH 7.4 were demonstrated as major and minor bands by their different electrophoretic mobilities. In the isoelectric focusing system also, two neutral DNases, a major one (IP, 4.6) and a minor one (IP, 6.4), were found. Characterization with respect to their histologic location showed acid and neutral DNases across the epidermal layers with the highest activities in the upper layers, where DNA concentration had been shown to be lowest. In correlation with their subcellular distribution, the highest activities of both acid and neutral DNase were found in the 105,00 X g supernatant of the subcellular fractions.

Animals↗