Biomedical subjects
S Tashiro
Publications and source records attributed to S Tashiro.
Acetyl-coenzyme-A carboxylase in cultured hepatocytes. Effects of exogenous fatty acids on the content, synthesis and degradation of the enzyme.
Studies were made on the content, synthesis and degradation of acetyl-coenzyme-A carboxylase in JTC-25 - P3 cells, hepatocytes which can be maintained in a protein-free and lipid-free chemically defined medium. The addition of corn oil or fatty acid to the medium resulted in a decrease in the activity level of the enzyme without impairing the viability of cells. All the fatty acids tested exhibited this effect, although linoleic acid and oleic acid were more effective than palmitic acid, stearic acid and arachidonic acid. Immunochemical titration and Ouchterlony double-diffusion analysis indicated that the decrease in the activity level of the enzyme observed in cells incubated in medium supplemented with fatty acid can be ascribed to a reduction of the quantity of the enzyme. Isotopic leucine incorporation studies with the use of immunochemical techniques demonstrated that this reduction of the enzyme content is due to a decrease in the rate of synthesis of the enzyme. The rate of degradation of the enzyme was essentially unaffected, the half-life being 25 and 28 h, respectively, in cells incubated in the presence and absence of fatty acid. It was shown that most of the isotopic fatty acid added to the medium was incorporated into cellular phospholipids, while a very small portion of it was recovered in triglyceride and nonesterified fatty acid.
[Pneumatosis cystoides intestinalis: a case report].
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L-leucine: a neuroactive substance in insects.
A compound was isolated from the blood of silkworm larvae, Bombyx mori, which had been prostrated with DDT; this compound increased the spontaneous discharge in the isolated abdominal nerve cord of the American cockroach, Periplaneta americana. The compound was identified as L-leucine.
[Three cases of neurinoma of the stomach].
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[Criteria of evaluation of efficacy of antibiotics. 1. Pericoronitis].
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[Clinical report on methyleneoxytetracycline in oral surgery].
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[The liver and steroid hormones. 3. Electron microscopic observations on the liver after anabolic steroid administration].
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[Comparison of spinal and extradural anesthesia].
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[Liver and steroid hormone. 2. Effects of prednisolone on liver transaminase activity in rats].
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On the Nature of the Nerve Impulse.
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Combination of intraoperative radiation with resection of cancer of the pancreas.
The utility of intraoperative radiation therapy (IORT) as an adjuvant to the surgical resection of pancreatic cancer was studied. In 1976, as our first trial with this combined therapy, we applied IORT with 30 Gy of electron beam with 8 MeV to 15 patients to prevent local recurrence around the celiac axis and superior mesenteric artery after standard pancreatectomy. However, the combined therapy did not show an improvement in survival rate as compared to that of 19 patients with standard operation alone. Autopsies of three patients with the combined therapy did not show involved lymph nodes in the radiation field, but did show local recurrence around the aorta outside the radiation field. By comparison, we performed extended operation without IORT on nine patients, with almost complete dissection of the lymph nodes around the aorta, from the diaphragm to the level of the inferior mesenteric artery. This extended surgery did not improve survival time, and autopsy showed local recurrence in spite of the dissection of lymph nodes. Therefore, since 1984, we have performed IORT with a dose of 30 Gy, 9 MeV, and an extended radiation field from the diaphragm above to the inferior mesenteric artery below, following extended operation on 14 patients. The five-year cumulative survival rate of these cases was 33.3%. Four autopsies showed improvement of local control rate. No radiation-related complications were noticed postoperatively in patients who underwent extended IORT following pancreatectomy. We were encouraged to continue this approach for the cure of pancreatic cancer.
Metabolic routes of cis- and trans-chlordane in rats.
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Inhibitory effect of retinoid on esophageal carcinogenesis in rats induced by N-nitroso-N-methylbutylamine in relation to cellular retinoic acid-binding protein.
The inhibitory effect of a synthetic retinoid, ethyl alltrans-9-(4-methoxy-2, 3, 6-trimethyl-phenyl)-3, 7-dimethyl-2, 4, 6, 8-nonatetraenoate (Tigason), on esophageal carcinogenesis in F344 rats induced by N-nitroso-N-methylbutylamine (NMBA) was evaluated. The animals were given NMBA daily in their drinking water for 21 weeks at a concentration of 15 mg per liter ad libitum starting at 8 weeks of age. One week before the beginning of NMBA treatment, the rats were divided randomly into Tigason-fed and -unfed groups. Thirty-five rats were fed a diet supplemented with Tigason at a concentration of 30 mg per kg of diet, and 80 rats were given a basal diet alone. In NMBA-treated rats, multiple papillomas were seen 11 weeks after NMBA treatment and squamous cell carcinoma developed 12 weeks after NMBA; the tumors increased in number thereafter, and the numbers of papillomas and carcinomas were the same at 17 and 21 weeks after NMBA. At 21 weeks after NMBA treatment, the number of papillomas was similar, regardless of the dietary Tigason supplement, however, the number of esophageal squamous cell carcinomas was significantly lower in the Tigason-fed rats than in -unfed animals (p < 0.025). In normal esophageal tissues, a small amount of cellular retinoic acid-binding protein (cRABP) was detected throughout the experimental period, while during carcinogenesis, the levels of cRABP increased continuously until 16 weeks after NMBA; the cRABP level was higher in papillomas than in squamous cell carcinomas. As Tigason specificially blocked the progression of papillomas to carcinomas, it may be a promising candidate chemopreventive agent in esophageal carcinogenesis.
Experimental and clinical studies on liver regeneration following transcatheter portal embolization.
BACKGROUND/AIMS: We studied compensatory hypertrophy following transcatheter portal embolization experimentally in dogs and clinically under the condition of cholestasis. METHODOLOGY: Experimental study: Sixteen dogs were used for this study. Transcatheter portal embolization was performed in the left lobes (70% of the total liver) using Gelfoam powder in dogs with 2-week obstructive jaundice. Liver weight, liver blood flow and the intracellular adenosine triphosphate content of isolated hepatocytes were measured after transcatheter portal embolization. Clinical Study: transcatheter portal embolization of the right portal branch was performed in 13 patients with cancer of the biliary tract and 3 patients with hepatocellular carcinoma before (extended) right lobectomy, using Gelfoam powder and thrombin. Six patients who had a total bilirubin level > 5 mg/dLunderwent a percutaneous transhepatic biliary drainage before transcatheter portal embolization. Liver function tests, a volumetric study with computed tomography and immunohistochemical staining for profilerating cell nuclear antigen and apoptosis in the resected livers were performed. RESULTS: Experimental study: The weight ratio of the non-embolized lobes to the total liver, 2 weeks after transcatheter portal embolization in the dogs with jaundice, was significantly lower than that of the normal dogs with transcatheter portal embolization (40.5 +/- 4.5% vs. 47.6 +/- 3.2%), but significantly larger than that of the dogs without transcatheter portal embolization. The cellular adenosine triphosphate content and tissue blood flow in the embolized lobes were significantly lower than those in the nonembolized lobes in the normal and cholestatic livers. Clinical study: The postoperative course in all patients was uneventful, with no serious complication or liver dysfunction. Extended right lobectomy with caudate lobectomy was equivalent to 65% before transcatheter portal embolization and to 56% after, transcatheter portal embolization owing to compensatory hypertrophy of the left lobe. However, there was no significant difference in liver volume in the patients with or without obstructive jaundice. Apoptosis was observed in the embolized lobe. CONCLUSIONS: Preoperative transcatheter portal embolization with percutaneous transhepatic biliary drainage for the purpose of liver regeneration would be useful for treating extended hepatectomy with obstructive jaundice.
Differential diagnosis of small hepatocellular carcinoma and borderline lesions and therapeutic strategy.
BACKGROUND/AIMS: To investigate imaging characteristics and surgical results of adenomatous hyperplasia and early-stage hepatocellular carcinoma. METHODOLOGY: A retrospective study set in the First Department of Surgery, University of Tokushima, Japan. From 1994 to 1997, 33 patients with 55 small hepatocellular carcinomas (< or = 3 cm) and 10 borderline lesions (3 adenomatous hyperplasia, 5 atypical adenomatous hyperplasia, 2 atypical adenomatous hyperplasia with focal malignancy) were enrolled for this study. The detectability of these lesions on imaging was evaluated. Cumulative survival and disease-free survival rates were also calculated. RESULTS: Twenty-eight patients were incidentally diagnosed on ultrasonography during follow-up study for chronic disease. In the conventional studies, detection rates of ultrasonography, computed tomography and angiography for small hepatocellular carcinomas and borderline lesions were 76% 80%, 33% 10% and 36% 20%, respectively. Magnetic resonance imaging, intraoperative ultrasonography, helical computed tomography and portal angiographic computed tomography showed better results of 67% 20%, 100% 90%, 70% 50% and 74% 56%, respectively. On differential diagnosis, the ratio of echo level in small hepatocellular carcinomas was significantly higher than that in borderline lesions. The 3-year and 5-year survival rates for all patients were 61% and 41%, while disease-free survival rates at the corresponding times were 15% and 7%, respectively. A total of 25 patients (76%) developed intrahepatic recurrence during a mean follow-up of 33.8 months, although there was no recurrent lesion in 4 adenomatous hyperplasia patients treated with microwave coagulation therapy and ethanol injection intraoperatively. CONCLUSIONS: For tumors larger than 1 cm in diameter, the detection rates with various diagnostic modalities were rather high. However, the differential diagnosis of borderline lesions from small hepatocellular carcinomas could be based on pathologic studies only. Early detection of small hepatic lesions and treatment by methods such as resection or ethanol injection are of critical importance in improving long-term survival.
Clarification of risk factors for hepatectomy in patients with hepatocellular carcinoma.
BACKGROUND/AIMS: Hepatic resection is still associated with a higher morbidity than other major abdominal surgery. The aim of this study was to define risk factors for postoperative morbidity, and to evaluate the plasma cytokine pattern to detect early postoperative infection in patients with hepatocellular carcinoma. METHODOLOGY: One hundred and thirty-nine hepatic resections for hepatocellular carcinoma over a 10-year period from 1987 to 1997 were performed. Preoperative and intraoperative predictors of morbid outcomes were analyzed using multiple regression in a stepwise, logistic model. The postoperative concentrations of interleukin-6, interleukin-8, granulocytecolony stimulating factor, endotoxin and hepatocyte growth factor were measured in 32 patients following hepatic resection. RESULTS: Mortality rate within 30 postoperative days was 2.2%, with morbidity occurring in 40.2%. Significant pre- and intraoperative predictors for morbidity were ICGR15 and the presence of liver cirrhosis. Changes of interleukin-6, interleukin-8, granulocytecolony stimulating factor and endotoxin levels were not consistent with the occurrence of postoperative complications. However, the postoperative peak hepatocyte growth factor levels were positively correlated with morbidity. CONCLUSIONS: ICGR15 and presence of liver cirrhosis had a marked effect on the incidence of postoperative complications after hepatectomy for hepatocellular carcinoma. An increase of serum hepatocyte growth factor level could be used to detect complications in the early postoperative period, but the inflammatory cytokine response after hepatectomy did not relate to an increased complication rate.
Gastric function after pylorus-preserving duodenectomy in dogs.
BACKGROUND/AIMS: The purpose of this study was to delineate the alterations in gastric physiology after pylorus-preserving duodenectomy (PPD). METHODOLOGY: The duodenum was transected 2 cm distal to the pyloric ring in five dogs. A patch graft around the papilla of Vater was preserved. Reconstruction was completed using an end-to-end duodenojejunostomy, anastomosis of the patch graft to the jejunum, and cholecystojejunostomy, in that order. Gastric acid analysis, serum gastrin and secretin concentrations, and gastric emptying were investigated before and one and three months after surgery. RESULTS: The postoperative mean basal and maximal acid outputs were not significantly increased. Fasting serum gastrin concentrations remained unchanged. The fasting serum secretin concentrations one month after surgery increased significantly as compared to the controls. There were no significant differences in meal-stimulated gastrin or secretin responses or gastric emptying after surgery. CONCLUSIONS: The acid output and gut hormone release after PPD were maintained at preoperative levels. Preservation of the duodenal bulb is postulated to be responsible for the maintenance of near-normal gastric physiology.