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Biomedical subjects

H Masuda

Publications and source records attributed to H Masuda.

At least 541 records · Page 30Linked to original sources
PubMed1986

Preoperative irradiation for carcinoma of the esophagus.

Preoperative irradiation for carcinoma of the esophagus is tentatively recommended in many, but not all, institutes. For precise appraisal of the effect of preoperative irradiation for carcinoma of the esophagus, the effects of preoperative irradiation, as related to mortality and the long term results, were evaluated in 167 patients who underwent subtotal esophagectomy. Although postoperative pulmonary complications occurred at a higher rate in patients given irradiation preoperatively, the mortality was much the same in irradiation and nonirradiation groups. In 15 (14.4 per cent) of 104 patients given radiation therapy preoperatively, no viable cancer cells were present in the resected tissues and the five year survival rate of these patients was 45.1 per cent. Thus, when the cancer cells are completely damaged, the survival time is extremely enhanced. The findings of our study suggest that the aim of preoperative irradiation should be a complete destruction of the cancer cells.

Aged↗
PubMed1985

Sodium bicarbonate in seminal plasma stimulates the motility of mammalian spermatozoa through direct activation of adenylate cyclase.

Recently, a low molecular weight factor, which specifically stimulates sperm adenylate cyclase, was found in porcine seminal plasma (Okamura, N., and Sugita, Y. (1983) J. Biol. Chem. 258, 13056-13062). The purified factor was analyzed by 1H NMR, 13C NMR, infrared spectroscopy, and elementary analysis and identified as sodium bicarbonate. The effects of sodium bicarbonate both on adenylate cyclase activity in porcine spermatozoa and on sperm motility have been studied. Sperm adenylate cyclase was found to be specifically activated by bicarbonate over the physiological concentration range. In contrast, the adenylate cyclase activity in other tissues was not affected. The same concentration range of bicarbonate which resulted in activation of adenylate cyclase also stimulated sperm motility. The motility and enzyme activity of spermatozoa in all species so far tested (human, bovine, rat, mouse, and dog) were found to be similarly sensitive to bicarbonate concentration. These results show that the bicarbonate-sensitive adenylate cyclase system regulates sperm motility and suggest that this system is common to all mammals.

Adenylyl Cyclases↗
PubMed1985

Primary hypothyroidism associated with pituitary enlargement, slipped capital femoral epiphysis and cystic ovaries.

A case of primary hypothyroidism with pituitary enlargement, slipped capital femoral epiphysis and cystic ovaries is reported. The pituitary abnormality and cystic ovaries disappeared dramatically after thyroid hormone therapy. Hip pinning was performed. The recognition of these associations may eliminate unnecessary surgery and lead to the choice of hormone replacement therapy.

Child↗
PubMed1985

Cytoplasmic microfilaments in endothelial cells of flow loaded canine carotid arteries.

To observe cytoplasmic microfilaments in the endothelial cells of flow-loaded arteries, an arteriovenous shunt was constructed between the common carotid artery and the external jugular vein in 26 dogs. After measuring the flow rates of the arteries, the endothelial layer was examined ultrastructurally with a transmission electron microscope at three different times: 1 week (acute experiments), 2-4 weeks (subacute experiments), and 4-7 months (chronic experiments). Six-to seven-nanometer microfilaments were found forming bundles, which usually ran longitudinally along the long axis of the vessel. In the acute experiments, the bundles increased in the endothelial cells of the flow-loaded arteries. They showed incomplete striation and were mostly located close to the basal cell membrane. In the subacute experiments, they showed an increase with the development of cross-striation. The half-desmosomal structure of the basal cell membrane had developed a close connection to the bundles. In the chronic experiments, the bundles were especially conspicuous around the intercellular junction. Tennanometer microfilaments increased in the endothelial cells of the flow-loaded artery in the subacute and chronic experiments. We consider that the bundles of 6- to 7-nm microfilaments might be structures developed to combat wall shear stress corresponding to actin filament stress fibers.

Actin Cytoskeleton↗
PubMed1985

Serum CEA levels facilitate detection of recurrences of cancer in patients after gastrectomy.

In an attempt to assess the usefulness of carcinoembryonic antigen (CEA) for predicting the progression of gastric cancer, CEA productivity was evaluated according to serum CEA levels, at the time of recurrence or relapse. In cases of a recurrence, abnormal CEA levels were observed in 14 of 17 (82.4 per cent) with differentiated carcinoma and in 9 of 21 (42.9 per cent) with undifferentiated carcinoma. Preoperative abnormal CEA levels were observed in only 6 of 41 patients (14.6 per cent). A median lead time of manifestation of recurrence was 5 months. In those with relapse, 9 of 11 (81.8 per cent) patients with differentiated carcinoma and 13 of 18 (72.2 per cent) with an undifferentiated carcinoma had abnormal CEA levels. Preoperative abnormal CEA levels were observed in 24 of these 89 patients (27.0 per cent). Postoperative monitoring of CEA seems to be useful for early recognition of gastric cancer progression, irrespective of the preoperative CEA levels.

Adenocarcinoma↗
PubMed1985

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↗
PubMed1985

The design of a pentavalent 99mTc-dimercaptosuccinate complex as a tumor imaging agent.

In our search for a technetium-tumor seeking agent, the chemical characteristic of polynuclear Ga-citrate attracted our attention. On this basis, we selected the ligand dimercaptosuccinic acid (DMS) and appropriate labeling conditions in the design of 99mTc(V)-DMS. Chemical characterization was performed by thin layer chromatography, electrophoresis, Sephadex column chromatography and spectrophotometric studies at the chemical concentration (99Tc). Biodistribution in mice bearing Ehrlich ascites tumor and scintigraphic images in VX-2 tumor-bearing rabbit, indicated the great applicability of 99mTc(V)-DMS as a new tumor imaging agent. Its distinctive characteristic, different from the kidney imaging agent (99mTc-DMSA) is demonstrated and the biological implication of hydrolytic polynucleation of pentavalent technetium, through an anionic specie Tc(V)O3-(4), in the tumor cell is discussed.

Animals↗
PubMed1985

A comparison of the tumor-seeking agent Tc-99m(V) dimercaptosuccinic acid and the renal imaging agent Tc-99m dimercaptosuccinic acid in humans.

Being aware of the ideal nuclear properties of Tc-99m, our interest has been focused on the design of the (+5) oxidation state Tc-99m(V) dimercaptosuccinic acid (Tc(V)-DMSA) as a tumor-seeking agent. Tc-99m(V) DMSA holds a TcO4(3-) core and, like PO4(3-), has excellent characteristics for tumor uptake, but has a different distribution than the well-known renal scanning agent, Tc-99m DMSA. The differences in chemical behavior of Tc-99m(V) DMSA and Tc-99m DMSA are discussed. Three cases in which neoplasms were studies with Tc-99m(V) DMSA and Tc-99m DMSA are presented. Tc-99m DMSA and Tc-99m(V) DMSA, having a common ligand and tracer but, with the metal ion core in a different oxidation state, the uptake characteristics are altered markedly.

Adrenal Gland Neoplasms↗
PubMed1985

Endothelial surface of the blood flow loaded canine carotid artery. A scanning and transmission electron microscopical study.

In order to study the ultrastructural changes of the endothelial surface induced by blood flow change, an arterio-venous shunt was constructed between the common carotid artery and the external jugular vein in 10 dogs. Blood flow rate was measured before anastomosis, after anastomosis, and after 1 week. After the final measurement (1 week), the arteries were fixed under normal pressure by 2.5% glutaraldehyde solution in phosphate buffer (pH 7.4) and were examined with scanning and transmission electron microscopes. Protrusion of nucleic parts of the endothelial cells, microvilli-like surface projections, and disturbance of pinocytotic vesicles predominated in the shunted arteries exposed to elevated blood flow. No significant ultrastructural changes could be defined in the intercellular junction of the endothelial cells which supported the increased permeability through the junction. It was suggested that the wall shear stress exerted a reactive change on the endothelial cells as well as a direct mechanical deformative effect in the endothelial plasma membrane.

Animals↗
PubMed1985

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↗
PubMed1985

[A case of immature mediastinal teratoma].

A case of mediastinal immature teratoma was treated with a multimodality approach that included surgery, chemotherapy, and radiotherapy. Serum alpha-fetoprotein at admission was elevated and changed in parallel with the therapy and tumor growth. The patient died of sudden respiratory failure 18 months after admission. Mediastinal immature teratoma with elevated serum levels of alpha-fetoprotein carries a poor prognosis, as does endodermal sinus tumor. We concluded that this condition should most probably be treated with a combination of intensive chemotherapy, surgical resection, and radiotherapy.

Adolescent↗