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Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 937 records · Page 52Linked to original sources
PubMed1975

Ultrastructural studies of perivascular cuffing cells in multiple sclerosis brain.

Perivascular cuffs in brains taken at autopsy from 6 patients with multiple sclerosis (MS) were examined by electron microscopy. Light and electron microscopy of brain revealed acute and chronic types of cuffs. The acute type of cuffs, consisting of many lymphocytes and lymphoid cells and a few lipid-laden macrophages, was usually seen in the nondemyelinated white matter or in the margin of the plaques, and infrequently within a plaque. The chronic type consisted mainly of macrophages, plasmacytoid cells, and plasma cells and was always seen within the plaques. In the parenchymal tissue of the white matter, macrophages participated in phagocytosis of myelin and axons, but no peeling or stripping of myelin sheath by inflammatory cells was observed. So-called paramyxovirus-like fuzzy filaments were observed in the nuclei of the mononuclear cells of perivascular cuffs obtained from 5 patients. The filaments were found predominantly in the acute rather than chronic type of cuffs. Specific antigens of measles and 6/94 viruses and intranuclear RNA corresponding to the filaments could not be demonstrated in the perivascular inflammatory cells by the immunofluorescence technique or acridine orange staining.

Autoimmune Diseases↗
PubMed1975

[Effect of carbon tetrachloride on biliary excretion of 3,4-benzpyrene in rats].

14C-labelled 3,4-benzpyrene (14C-BP) in dose of 100 mug/animal was injected into female Sprague-Dawley rats under urethane anesthesia. The rats were cannulated at the duct and the output of metabolites in the bile was determined. Non-treated rats excreted 35.5% of the given dose within one hr. The main metabolites excreted in bile were fractionated chromatographically into three. One of these was a metabolite which was hydrolyzed by beta-glucuronidase, the other two were unknown substances. Unchanged BP was not detected. In rats pretreated with CCl4 (0.5 ml/kg, p.o.) 24 hr before experiment, the biliary excretion of BP-metabolites was found to be reduced, that is only 10% of the given dose was excreted within one hr. It was noted that the output within the first 90 min after injection of BP was significantly reduced. In the CCl4-treated rats, bile flow was found to be lowered. However, the reduced output of BP-metabolites was considered not as the result of lowered bile flow, but as the result of disturbance of BP-metabolism in the liver. Thus it is suggested that impaired hepatic junction as the result of CCl4 intoxication may last for more than two weeks, when the hepatic junction is evaluated in terms of biliary excretion of BP.

Animals↗
PubMed1975

Experimental parainfluenza-type-1-virus-induced encephalopathy in the adult mouse. An ultrastructural study of early lesions.

The adult mouse inoculated intracerebrally with 6/94 strain of parainfluenza type 1 virus developed selective degenerative lesions in cerebral white matter. Ultrastrucrally, the infiltration of mononuclear cells, mostly lymphoid cells, apparently preceded the alterations of white matter parenchyma. The prominent feature of the white matter lesion was a lytic degeneration of both axon and myelin that seemed to be triggered by the mononuclear cell infiltration. Nucleocapsids of paramyxovirus were found only in ependymal cells and the very early stages of the infection. It is suggested that the mechanism of the white matter degeneration might be that of a virus-induced cell-mediated immune response directed at both the axon and myelin.

Animals↗