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Biomedical subjects

S Seno

Publications and source records attributed to S Seno.

At least 55 records · Page 3Linked to original sources
PubMed1984

Experimental autoimmune glomerulonephritis with pulmonary hemorrhage in rats. The dose-effect relationship of the nephritogenic antigen from bovine glomerular basement membrane.

Experimental autoimmune glomerulonephritis with pulmonary hemorrhage was induced in rats by a single injection of soluble antigen obtained from bovine glomerular basement membrane. Groups of rats were injected with various amounts of the nephritogenic antigen with Freund's complete adjuvant and killed 10 weeks later. Glomerulonephritis with linear deposition of IgG along the glomerular basement membrane developed in 7 of 10 rats injected with 10 micrograms of the antigen and all 20 rats of other 2 groups with 100 or 1,000 micrograms of the antigen. Pulmonary hemorrhage was observed in 21 of 27 rats with nephritis, and it was particularly severe in those injected with 1,000 micrograms. Glomerulonephritis with pulmonary hemorrhage and the linear deposition of IgG along with the glomerular basement membrane suggests that this model resembles human anti-glomerular basement membrane antibody-induced glomerulonephritis including Goodpasture's syndrome. The nephritic rats showed symptoms of nephrotic syndrome such as hypoalbuminemia, hypercholesterolemia and hypertriglyceremia, and the severities of these symptoms clearly depended on the degree of proteinuria.

Animals↗
PubMed1983

Cationic cacodylate iron colloid for the detection of anionic sites on cell surface and the histochemical stain of acid mucopolysaccharides.

Stable cationic iron colloid solution was prepared by mixing the Hale's iron colloid (Hale 1946; Mowry 1963) with sodium cacodylate buffer solution. The colloid particles obtained were 30-50 A in size and kept their positive charges in a wide range of pH 1.8-7.6. Observations made on rat kidney tissues proved that this iron colloid solution is promising for the detection of anionic sites of cell surface in fixed tissues as well as in living cells in place of cationic ferritin.

Animals↗
PubMed1983

Macromolecular charge and cellular surface charge in adhesion, ingestion, and blood vessel leakage.

To get reliable information about the role of charged groups of tissue components on the integrity of blood circulation, the staining and perfusion experiments of rat organs with cationic (cacodylate iron colloid) and anionic iron colloid (chondroitin iron colloid) particles were carried out. These cationic and anionic iron colloid particles are stable in a wide range of pH's. Dissociation curves of several tissue components at varied pH levels were observed for the analysis of the results obtained by histochemical observations and perfusion experiments. The results indicated that all the intra- and extracellular spaces of living tissues are surrounded by the ionized anionic groups. No ionized cationic groups were found except on the macrophage surface. The cationic iron colloid particles perfused into organs through vessels adhered to the endothelial cell surface inducing the swelling of the cells. The cationic particles invaded into surrounding tissues passing through the damaged endothelial layer, but plasma protein leakage did not occur being prevented by the newly formed fibrin-fibrinogen lining. The anionic iron colloid particles introduced into vessels did not adhere to blood vessel walls but were taken by reticuloendothelial cells or macrophages. The importance of the ionized anionic groups of proteins on the endothelial cell surface and surrounding tissues for the integrity of blood vessel function was stressed.

Animals↗
PubMed1983

Regulation of hexitol catabolism in Streptococcus mutans.

Regulation of hexitol catabolism was investigated in Streptococcus mutans, a cariogenic human dental plaque bacterium. Induction of hexitol catabolic enzymes and phosphoenolpyruvate:hexitol phosphotransferase and hexitol phosphate dehydrogenase activities was regulated by an inducer exclusion mechanism initiated by D-glucose and 2-deoxy-D-glucose. Kinetic analysis of the inhibitory effect of 2-deoxy-D-glucose on initial hexitol uptake illustrated that this was a noncompetitive type of inhibition. In mutant strains of S. mutans lacking phosphoenolpyruvate:glucose phosphotransferase activity, 2-deoxy-D-glucose was unable to inhibit hexitol uptake. These observations provide evidence for possible molecular mechanisms for the exclusion process.

Biological Transport↗
PubMed1983

A morphological study of ferritin synthesis in macrophages with ingested ferric hydroxide-potassium polyvinyl sulfate complexes.

A ferric hydroxide-polyvinyl sulfate colloidal solution (Fe-PVS), prepared by mixing potassium polyvinyl sulfate (PVSK) and ferric hydroxide colloidal solution was used to study ferritin synthesis in rat peritoneal macrophages. The colloidal particles had spherical electron opaque ferric hydroxide cores with diameters of about 250 nm surrounded by radially arranged fibrous PVS molecules. They also had strong negative electric charges. Fe-PVS particles injected into the peritoneal cavity were taken up by the macrophages then disintegrated rapidly. In the phagolysosomes the electron opaque ferric hydroxide cores of Fe-PVS were denuded of their PVS frames then decomposed into small 5-6 nm granules 24 to 48 h after injection. These small granules were released from the lysosomes into the hyaloplasm and the myelin figures were found in the lysosomal vacuoles. No reaccumulation of granules in lysosomes was found even 3 months later. The intracellular distribution of ferritin in macrophages demonstrated by the immunocytochemical method showed a pattern similar to that of the small granules formed by the disintegration of Fe-PVS. This means that in rat peritoneal macrophages that contain ingested Fe-PVS particles ferritin first is synthesized in phagolysosomes by the ferric hydroxide cores that conjugate with apoferritin or protein subunits then they are dispersed into the cytoplasm. Two possible pathways for the biosynthesis of ferritin are discussed.

Animals↗
PubMed1983

The anionic barrier of blood vessel walls and the possible pathologic changes due to the deionization of the barrier and plasma proteins.

For the purpose to observe the possible vessel wall damage by deionization of the related anionic groups the perfusion test of rat kidney and aorta with cationic iron colloid particles and the injection experiments with albumin-poly-L-lysine complex were carried out. By staining the fixed tissue sections with the cationic iron colloid at pH 7.3 the ionized anionic sites on vessel walls have been demonstrated histochemically. The perfusion test of living tissue with the cationic iron colloid induced the desquamation of the endothelial cells. The perfused colloid particles were adsorbed to the whole endothelial cell surfaces facing to luminal and subluminal sides. Albumin-poly-L-lysine complex injected into vein deposited in the subendothelial spaces of glomerular capillaries through the endothelial cell layer having the well-kept anionic barriers. Discussion was made on possible damage of vessels due to the deionization of anionic groups of endothelial cells and serum proteins by general cationic molecules.

Adsorption↗
PubMed1982

"Pseudo-cap" formation in Ehrlich ascites tumor cells induced by cytochalasin B.

Cytochalasin B (CB) treatment induces or accelerates the capping phenomenon in some cells. In Ehrlich ascites tumor cells (EATC) CB treatment apparently induced the capping of Con A binding sites as observed under a fluorescent microscope. However, electron microscopic examinations revealed that the CB treatment did not induce a rearrangement of Con A binding sites, but rather it only induced a change in cell shape. On the contrary, CB treatment inhibited the capping phenomenon induced by treatment with Con A. Electron microscopic observations may give exact information on the distribution of lectin binding sites.

Animals↗
PubMed1979

Induction of diabetes in animals by parenteral administration of ferric nitrilotriacetate. A model of experimental hemochromatosis.

Rats and rabbits parenterally treated with a large daily dose of ferric nitrilotriacetate manifested diabetic symptoms such as hypergycemia, glycosuria, ketonemia, and ketonuria after approximately 60 days fo treatment. The blood insulin response to oral glucose loading was poor. Heavy iron deposits were found in liver parenchymal cells and in pancreatic exocrine cells, although some iron was deposited in the macrophages and reticuloendothelial cells of the organs. Faint iron staining was found in some pancreatic islet cells, with a reduction in beta granules and weak zinc staining. Cirrhotic liver changes and skin pigment deposition were not observed. Repeated blood withdrawals from ferric-nitrilotriacetate-treated animals resulted in disappearance of hypergycmia, glycosuria, ketonemia, and ketonuria; disappearance of iron from the liver and pancreas; and restoration of islet beta granules to the control level.

Acetates↗
PubMed1979

[Intracranial hemorrhage in autopsy cases with occlusion of the circle of Willis (author's transl)].

Seventeen autopsy cases with occlusion of the circle of Willis were examined clinicopathologically. These patients ranged in age from 8 years to 64 years and consisted of 6 males and 11 females. The following results were obtained. 1. Fresh and massive intracerebral hemorrhage was confirmed in 13 of 17 patients and cerebral infarct in 4 of 17 patients. 2. Among these 13 patients, massive hemorrhage was found in basal ganglia, thalamus and hypothalamus of 9 patients, and in thalamus, cerebral peduncle and midbrain of 4 patients. 3. Rupture of the dilated muscular-type arteries was noted in the thalamus and basal ganglia in 2 of 13 patients. Ruptured arteries with organization of the lumen were found in the old hemorrhagic foci in one of them. 4. Overgrown and dilated arteries, branching off from the circle of Willis, were confirmed in 11 patients. These arteries consisted of "perforating" arteries well developed as collateral circulation. 5. No ruture in these arteries of the subarachnoidal spaces was found in 11 patients. In one of them, a small saccular aneurysm was found. These findings strongly suggest that in patients with occlusion of the circle of Willis intracerebral rupture of overgrown "perforating" arteries as collateral circulation may be the main cause of intracranial hemorrhage and intracerebral hemorrhage due to rupture of the arteries may be repeated.

Adolescent↗
PubMed1978

Malignant pituitary chromophobe adenoma in an infant accompanying diabetes insipidus.

This report deals with a 1.5-year-old male infant terminating in viral pneumonia and "diabetes insipidus". The autopsy revealed malignant pituitary chromophobe adenoma, invading the wall of the third ventricle, extending to the periventricular-, dorsomedial- and ventromedial area, skipping to the lateral area adjacent to the optic nerve, and permeating into the subarachnoid space of the cerebrum. At the onset of disease polydypsia and polyuria were marked followed by interstitial pneumonia with high fever, and later generalized tonic convulsion terminated in death. This case is peculiar in at least two respects. Firstly, this is the youngest reported case of malignant chromophobe adenoma. Secondly, the manifestation of diabetes insipidus is rare in chromophobe adenoma. The malignant adenoma probably occurred from the primitive gland rest of chromophobe cells in the posterior lobe becoming malignant during the course of growth development and destroyed the cells of the posterior lobe, resulting in diabetes insipidus.

Adenoma, Chromophobe↗
PubMed1977

Changes in structural organization of surface membrane during erythrocyte maturation.

The effect of concanavalin A and its succinylated derivative on cell agglutination and potassium compartmentation of mature and immature erythrocytes was observed. The binding of tetravalent concanavalin A to the surface glycoproteins of rabbit erythrocytes leads to a change in the properties of the surface membrane, which results in an induction of cell agglutination and concomitant release of potassium from the cells. Both of the phenomena induced by concanavalin A are temperature dependent, and observed at above 15 degrees C. Divalent succinylated concanavalin A, lacking the inducing activity of surface glycoprotein cross-linking into patches and caps, caused neither cell agglutination nor change in the potassium compartmentation of erythrocytes and reticulocytes. In the case of immature reticulocytes, however, remarkable agglutination of the cells was induced without a change in the potassium compartmentation after treatment with tetravalent concanavalin A. It is suggested that changes in the molecular organization of the surface membrane occur in which potassium compartmentation of the reticulocytes becomes more susceptible to surface glycoprotein cross-linking during cellular maturation.

Animals↗
PubMed1976

Hemopoietic recovery in bone marrow of lethally irradiated rats following parabiosis. I. Granulopoiesis.

Aplasia was induced in rats by total body irradiation. Three days later, the animal was conjugated by aortic anastomoses with a healthy untreated litter-mate. 6 h after parabiosis, the bone marrow of irradiated animals contained some granulocytes showing RNA synthesis. At 18 h, many myelocytes and promyelocytes were present but no myeloblast was encountered. These myeloid precursor cells showed active DNA synthesis but no mitoses, and no erythroblasts were observed at this time period. At 24 h, mitoses of myeloblasts were found. At 42--60 h, erythropoiesis was evident. Chromosome analysis and investigations of cells of irradiated parabionts conjugated with partners having labeled cells, revealed that these newly formed myeloid and erythroid cells originated from the untreated parabiont. The mechanism of triggering myelopoiesis in the aplastic bone marrow by parabiosis is discussed.

Animals↗