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Biomedical subjects

T Mitsuhashi

Publications and source records attributed to T Mitsuhashi.

At least 145 records · Page 8Linked to original sources

Intraoperative blood pressure control by ATP in pheochromocytoma.

Three cases of pheochromocytoma which were successfully treated with the use of adenosine triphosphate (ATP) during the operation are reported. The mechanism of the hypotensive effect of ATP has been proved due to the antagonizing action of the agent to the vasoconstriction by noradrenaline and/or sympathetic nerve stimulation. In these 3 cases, ATP has been safely and effectively applied to control blood pressure in pheochromocytoma. ATP could be used as the first-choice drug to keep the circulatory state stable during surgery for pheochromocytoma.

Adenosine Triphosphate↗

A new disk method for the endoscopic determination of gastric ulcer area.

The authors devised a new method using measure plates for the endoscopic measurement of gastric ulcer area. A grid composed of 2.5-mm squares was photographed by the endoscope with lens-object-distance (LOD) being changed every 2.5 mm precisely, and the obtained images of the square pattern were printed on glass plates, which were used as measure plates. The ulcer size was determined by mounting an endoscopic photograph of the ulcer on the corresponding glass plate with the same LOD, projecting them on the screen by a projector and counting the number of squares within the ulcer area. In this way the gastric ulcer size could be determined with an average aberration ratio of 5.6% or less, irrespective of LOD.

Gastroscopy↗

Giant to small emphysematous bullae induced by Sephadex beads and carrageenan.

The effects of disturbances of the pulmonary circulation on the formation of pulmonary emphysematous bullae in rabbits were studied with the use of changes in the parenchyma of lungs insulted by both pulmonary embolization with Sephadex beads and carrageenan-induced pneumonia. Rabbits given one of the larger doses of Sephadex and then carrageenan in solution had giant bullous lesions in the lobe treated with those agents 2 months later. More animals had bullous lesions in the groups given the larger doses of Sephadex than in groups given the smallest dose or none. In animals killed after 2 weeks, bullous lesions were found, whereas there were none in those killed after 1 week. These results suggest that the size and number of bullous lesions forming in the treated lobes are associated with the dose of Sephadex. Giant and small bullous lesions are varieties of the same disorder, and there seems to be a latent period for development.

Animals↗

[Primary malignant melanoma of the esophagus].

A case of primary malignant melanoma of the esophagus is reported. The patient was a 44-year-old man. The tumor occupied Ea approximately C (E less than C) and was a large protruding mass. Partial esophagectomy (Ei approximately Ea) and total gastrectomy with splenectomy (R2), postoperative adjuvant chemotherapy (DTIC.CDDP) and radiation against the metastatic lesion of the right adrenal were performed. The patient died eight months postoperatively with massive multiple metastases to the liver. Histologically, the tumor tissue was diagnosed as primary malignant melanoma of the esophagus with junctional change and esophageal melanocytosis.

Adult↗

Peroxidatic degradation and ether link cleavage of thyroxine in a particulate fraction of human thyroid.

The present study was undertaken to investigate degradation of thyroxine (T4) mediated by thyroid peroxidase in man. A particulate fraction (1,000-100,000 x g) of normal human thyroid tissue was prepared and used as crude enzyme. 125I-T4 and unlabeled T4 were incubated with the particulate fraction in buffer containing glucose and glucose oxidase for generation of H2O2. After incubation, iodoamino acids were extracted with ethanol and the products of T4 degradation were analyzed by thin layer chromatography. In this system, T4 was degraded in time-, temperature- and pH-dependent manners, but not in the absence of the H2O2-generating system. The rate of degradation was related to concentration of the particulate fraction. The reaction was inhibited by methimazole, propylthiouracil and catalase. When [3',5'-125I] T4 was used as a tracer, major labeled products of T4 degradation were inorganic iodide and ethanol-unextracted fraction and no detectable labeled 3,5,3'-triiodothyronine (T3) or 3,3',5'-triiodothyronine (rT3) was generated. From a kinetic study by adding various doses of unlabeled T4, the apparent Km value for T4 was 30 microM and the Vmax value was 230 pmol/mg protein/min. When [3,5-125I] T4 was incubated with enzyme preparation, one third of degraded T4 was recovered as diiodotyrosine (DIT) and half of 125I-DIT was degraded in parallel incubation. No formation of radiolabeled DIT was observed in incubation with Na- 125I done in tandem. These findings suggest that thyroid hormones can be metabolized by peroxidase in human thyroid by pathways that include cleavage of ether linkage.

Autoradiography↗

Experimental pulmonary fibrosis induced by trisodium citrate and acid-citrate-dextrose.

A single intrapulmonary injection of 3.8% trisodium citrate and acid-citrate-dextrose (ACD) into rabbits results in extensive degeneration and necrosis of alveolar pneumocytes, including the type II pneumocyte, and of bronchiolar or bronchial epithelial cells. Subsequently, the alveoli and alveolar ducts collapse, and the septa and ductal walls adhere to each other, accompanied by the proliferation of interstitial fibroblasts. These fibroblasts produce fibrous connective tissue which is followed by pulmonary fibrosis in 1 week. Epithelial regeneration, especially that resulting from the proliferation of immature type II pneumocytes, occurs around the periphery of the fibrous lesions. The synthesis and release of large amounts of surfactant materials by the proliferated type II pneumocytes may induce the surfactant materials to reopen the air spaces of the collapsed and adhesive alveoli. By 4 weeks those fibrous areas in the pathological lungs become smaller and/or appear normal. These results suggest that this is a useful experimental animal model for pulmonary fibrosis, and that epithelial cells, especially type II pneumocytes, are associated with both the induction of and the recovery from the disorder; in the early stage, interference by reepithelization resulting from type II pneumocyte proliferation may elicit the proliferation of fibroblasts, and in later stages, reepithelization and surfactant synthesis by newly proliferated type II pneumocytes may permit the reopening of collapsed and adhesive air spaces.

Animals↗

Effects of phorbol ester on GH, TSH and PRL release by superfused rat adenohypophysis.

The present study was undertaken to examine the effects of 12-0-tetradecanoyl-phorbol-13-acetate (TPA), one of the potent tumor promoting agents, on GH, TSH and PRL release by rat adenohypophyseal dispersed cells and fragments, using a superfusion technique. TPA (10(-6) to 10(-5) M) stimulated GH release from acutely dispersed rat adenohypophyseal cells. Neither TSH nor PRL was affected, but both were increased by TRH in a dose-dependent fashion (10(-9) to 10(-7) M). In fragments, TPA (10(-8) to 10(-6) M) elicited a dose-related release of GH. Exposure of the fragments to 10(-6) M TPA for 5 min promptly caused a 5-fold increase in GH release which continued for at least 40 min after stopping the stimulation. The addition of somatostatin (SRIF) (10(-7) M) decreased basal GH release and abolished GH release induced by 10(-6) M TPA. In contrast to GH, neither TSH nor PRL release was affected by TPA, but both were stimulated by TRH. These results indicate 1) that GH release is more sensitive to stimulation with TPA in normal rat anterior pituitaries in vitro than the release of TSH and PRL, and 2) that SRIF abolishes TPA-induced GH release.

Animals↗

Experimental emphysematous bullae induced by methylcholanthrene and carrageenan.

An animal model for the emphysematous bullae in the rabbit lung induced by methylcholanthrene and carrageenan was reported. In early stages (by 2 months) the cystic lesions associated with extensive pneumonia. In later stages the inflammation subsided and only the cystic lesions remained, resulting in typical, large emphysematous bullae.

Animals↗

[A case of primary lymphoma of the stomach, diffuse lymphoplasmacytic type, with massive hematemesis].

A case of primary lymphoma of the stomach with massive hematemesis and melena who underwent emergency gastrectomy is reported. The patient was a 72-year-old woman. The tumor was 3.5 X 3.0 cm in size and occupied the posterior wall of the upper part of the gastric body. The surface of the tumor was covered with hematoma, and was there was a lack of gastric mucosa. Histological diagnosis of the tumor was primary gastric lymphoma, diffuse lymphoplasmacytic B-cell type, and monoclonal kappa-light chain was demonstrated by the immunohistochemical method. The bleeding source of the tumor tissues was a ruptured artery invading the tumor tissue in the submucosal layer of the stomach.

Aged↗

Effects of intrathyroidal metabolism of thyroxine on thyroid hormone secretion: increased degradation of thyroxine in mouse thyroids stimulated chronically with thyrotrophin.

Mice were infused continuously with graded doses of bovine TSH (bTSH) and changes in plasma concentrations of bTSH and T4 were measured. Then mice infused with 100 mU TSH per day were sacrificed on days 0, 1, 3 and 5 and their thyroids were excised to determine in vitro secretion of T4, T3 and rT3 during 3 h of incubation. At the end of the incubation, thyroidal contents of T4, T3 and rT3 were also determined after pronase digestion. Plasma bTSH levels were increased on day 1 to a level of 110 microU/ml and remained unchanged thereafter. Plasma T4 concentrations increased approximately 2-fold on day 1, but decreased to initial levels on days 3 and 5. Changes in T4 secretion in vitro paralleled those in plasma T4 concentrations; T4 secretion increased 2-fold on day 1, and decreased to the pre-TSH levels on days 3 and 5. In contrast, T3 secretion increased throughout the experimental period. The T3/T4 ratio in thyroidal secretion in vitro was the same as that in thyroidal contents on days 0 and 1 of TSH infusion, but the former was significantly greater than the latter on days 3 and 5. PTU (5.9 X 10(-5) M), a known inhibitor of T4 deiodination, added to the incubation media did not affect T4 secretion on days 0 and 1, but increased T4 secretion on days 3 and 5 to the level of day 1, but did not affect T3 secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗