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Biomedical subjects

M Kitazawa

Publications and source records attributed to M Kitazawa.

At least 91 records · Page 5Linked to original sources
PubMed1983

Ultrastructural characteristics of duodenal somatostatinomas. II. Granules and vesicles.

Ultrastructural findings of granules and vesicles appearing in tumor cells of somatostatinoma are reported. Except for D granules, one granule and four kinds of vesicles were discerned. Some tumor cells had granules of the exocrine type which were similar to those of the chief cells of the stomach. Very small clear vesicles (YO and KO) had accumulated mainly in the apical region of the somatostatinoma cells. Both vesicles were round, unit-membrane bounded and clear in the center, each measuring about 90 and 30 nm in diameter. The cored vesicles normally seen in the sympathetic system were revealed. Doughnut vesicles characterized by double contour membranes were detected together with the cored vesicles. A mixture of exocrine cells of the chief cell-type in the paraneuroma has not been previously reported. And we have as yet very little information as to the doughnut vesicle.

Adenoma, Islet Cell↗
PubMed1983

Duodenal somatostatinoma. Immunohistopathology and review of literature.

A case of duodenal somatostatinoma is reported. The patient, a 54-year-old male, had complained of an epigastric pain due to gastric ulcer and a duodenal polyp was unexpectedly found at a gastrectomy. The polyp showed basically tubular adenocarcinoma, with negative argyrophil and argentaffin reactions. By an indirect immunofluorescent examination almost all of the tumor cells were revealed as somatostatin-immunoreactive. Big somatostatin was also positive. Radioimmunoassay of the tumor indicated 6400 pg of somatostatin-like immunoreactivity per milligram of wet tissue. This seems to be the second case of duodenal somatostatinoma, following the case reported by us previously.

Adenoma, Islet Cell↗
PubMed1983

An ultrastructural study of the morphogenesis of membranocystic lesions in bone marrow.

A biopsy case of a man aged 30 years, who was admitted to the hospital for the fracture of his right talus, was reported. The X-ray analysis of his extremities revealed multifocal cystic lesions in bilateral tali, and carpal bones. Pathological examination of the cystic lesions of the bilateral tali showed the membranocystic lesion (MCL), which morphologically resembled that of "membranous lipodystrophy" reported by NASU et al. Minute tubulovesicular structure of the MCL observed in this case was proved to arise at the lipid-cytoplasmic-interface of degenerated fat cells and enter into the interstitium to form MCL, concurrently with collapse of the fat cells. Thus, at least one process responsible for the morphogenesis of MCL could be determined by our electron microscopic examination.

Adult↗
PubMed1983

Cardiovascular effects of digitalis on intact dogs and isolated cross-perfused atria.

The chronotropic effects of digoxin and deslanoside were studied in canine atria cross-perfused with heparinized arterial blood from donor dogs. Intravenous injections of either drug (100 micrograms/Kg) into the donor dog produced bradycardia followed by ventricular tachyarrhythmia, with or without hypertension, in the donor dog. A significant increase in the developed tension was observed in the isolated atria, with or without slight sinus acceleration. These effects continued over 150 min after the injection. Digoxin (200 micrograms/Kg, i.v.) caused an immediate bradycardia followed by ventricular tachycardia. In addition, ventricular fibrillation occurred in 3 out of 5 donor dogs within 20 min of the drug administration. In isolated atria, there was a marked increase in the developed tension, usually with a little sinus tachycardia. Deslanoside (200 micrograms/Kg, i.v.) caused almost the same response patterns as digoxin. However, this dose of deslanoside caused ventricular fibrillation in all 6 experiments. Drug concentrations in the donor's arterial blood decreased rapidly for 15-20 min and then decreased slowly in all experiments. It is concluded that digoxin and deslanoside have no significant direct accelerating action on the SA node in doses which produced marked increases in the developed tension; only extremely high doses cause a direct, slight sinus acceleration.

Animals↗
PubMed1983

Ultrastructural characteristics of duodenal somatostatinomas. I. Somatostatinoma cells and Schwann-like cells.

This report describes the general ultrastructural characteristics of somatostatinoma cells and Schwann-like cells in two cases of duodenal somatostatinomas. Duodenal somatostatinoma cells had common findings to endodermal cells, i.e. the granules of exocrine type, intracytoplasmic canaliculi, microvilli, small clear vesicles and others. This may suggest that endocrine cells of the gut are of endodermal origin. On the other hand, a few Schwann-like cells were discovered in the tumor nests. Schwann-like cells surrounding the nest of tumor cells were characterized by multilayered piled up cytoplasm, abundant microfilaments and others. This fact suggests that somatostatinoma has some relationship to the nerve.

Adenoma, Islet Cell↗
PubMed1982

Long term experiment of perfluorochemicals using rabbits.

Morphological changes six months of two years after the administration of Perfluorochemicals (PFC) in rabbits injected with a large amount of PFC (67 mg/kg) have already been reported by Ohnishi and Kitazawa (1979, 1980, and 1981). In this paper, the authors report on the persistence of large numbers of foamy cells in the liver, spleen and lymph nodes and many in the kidneys, lung and bone marrow, up to two years after administration. Quantitative analysis of PFC in various organs showed that it was retained. The liver revealed progressive fibrosis surrounding the foamy cells in or around the Glisson's sheath.

Animals↗
PubMed1981

Mechanism of chlorpromazine-induced arrhythmia -- arrhythmia and mitochondrial dysfunction.

In this study, we investigated the mechanism of the arrhythmogenic action of chlorpromazine (CPZ). Thirty-two anesthetized mongrel dogs were used. In each, the chest was opened and a stimulating electrode was attached to the apex of the left ventricle and the ventricular multiple response threshold (VMRT) was measured. The carotid artery was cannulated to measure aortic pressure. The dogs were divided into four groups, and the time course of VMRT, blood pressure, and heart rate were determined. All groups were placed under observation for 30 min after CPZ infusion. In the control group, only saline (2ml/kg) was infused; CPZ group: CPZ (Img/kg) was infused 10 min after saline (2ml/kg) infusion; CoQ10 group: Coenzyme Q10 (CoQ10) (5mg/kg) was infused 10 min before CPZ (Img/kg) infusion; FAD group: Flavin-adenine-dinucleotide (FAD) (2mg/kg) was infused 10 min before CPZ (Img/kg) infusion. In each group, myocardial mitochondria were prepared 30 min after CPZ infusion. The mitochondrial functions, respiratory control index, AdP/O, State III rate of oxygen consumption, and activities of two segments of the electron-transport chain (NADH leads to CoQ leads to cyt.c and cyt.c leads to cyt.a,a3 leads to O2) were measured separately. Ca++--binding activity of the mitochondria was also determined. CPZ administration decreased VMRT and blood pressure, and caused mitochondrial dysfunction which derived from a disturbance in the first segment of the electron transport chain. Decreased Ca++--binding activity was observed when mitochondrial function was disturbed. CoQ10 prevented significantly the decrease in VMRT and the disturbance of mitochondrial function induced by CPZ, but did not prevent the hypotensive effect of CPZ. FAD prevented not only the decrease in VMRT and the disturbance of mitochondrial function, but also the hypotensive effect of CPZ. These results suggest that the decrease in VMRT is closely related to mitochondrial dysfunction induced by CPZ. Moreover, it is suggested that the arrhythmogenic effect of CPZ is derived from the decreased mitochondrial Ca++--binding activity.

Animals↗
PubMed1980

Application of perfuluorochemicals in human beings-- a morphological report of a human autopsy case with some experimental studies using rabbit.

The first autopsy case of a patient treated with Perfluorochemicals (PFC, fluorocarbon) for hemolytic anemia, occurring after an operation for dissecting aneurysm, is reported. The results of preliminary experiments on the effects of histopathological manifestation of tissue with the administration of Perfluorochemicals in rabbit are also described. Both in human and experimental materials, the reticuloendothelial organs, blood monocytes and macrophages including histiocytes were markedly blocked in their phagocytic activities in every portion of the organs examined, and transformed themselves into ballooning foamy cells upon administration of PFC. Morphologically, the excretion of this chemical from either the lung or the urinary system can not be certified. The particles compatible to Perfluorochemicals are still found in the cytoplasm of cells in various organs, a full four months after the administration of Perfluorochemicals in the experiments. It is evident that further studies are necessary, regarding the use of Perfluorochemical in human beings.

Anemia, Hemolytic↗