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H Shio

Publications and source records attributed to H Shio.

At least 91 records · Page 5Linked to original sources
PubMed1981

Relationship between peroxisomes and endoplasmic reticulum investigated by combined catalase and glucose-6-phosphatase cytochemistry.

The theoretical advantages of electron microscopic cytochemistry were utilized to look for evidence of possible connections between peroxisomes and the endoplasmic reticulum in rat liver. Established cytochemical procedures for catalase (peroxisomes) and glucose-6-phosphatase (endoplasmic reticulum) were carried out, and evidence was sought of diffusion of reaction products between the organelles. No such diffusion was observed: lead phosphate was found in the endoplasmic reticulum and in the nuclear envelope but not in peroxisomes; oxidized diaminobenzidine (DAB) was seen only in peroxisomes. In addition, both types of cytochemistry were carried out on the same tissue. The two kinds of reaction product could be distinguished by virtue of their different electron opacities. No mixing of the two reaction products was observed. These results do not support the hypothesis that peroxisomes and endoplasmic reticulum may be connected; rather, they support the idea that the two organelles exist as separate cellular compartments.

3,3'-Diaminobenzidine↗
PubMed1979

Characterization of lipid-laden aortic cells from cholesterol-fed rabbits. III. Intracellular localization of cholesterol and cholesteryl ester.

The subcellular sites of accumulation of cholesterol and cholesteryl esters in rabbit atheromatous cells, were investigated by morphologic and biochemical techniques. Electron microscopy of lipid-filled cells in situ in atheromatous aortas of cholesterol-fed rabbits revealed lipid accumulation in the cytoplasm as lipid droplets and within lysosomes in the form of lipid globules, membranous whorls, and crystals. When such cells were isolated from the rabbit aortas by enzymic digestion, and then treated with Flickinger's aldehyde fixative containing 0.2 per cent digitonin, characteristic digitonide-lipid complexes ("spicules") were observed in discrete sites of the cytoplasm distinct from the cytoplasmic droplets. If these cells were first stained cytochemically for acid phosphatase and then treated with digitonin-aldehyde fixative, enzyme reaction product was found associated with the spicules indicating that the lysosomes of the atheromatous cells possess digitonin-reactive lipid. Subcellular fractionation of isolated rabbit aortic foam cells by sucrose density gradient centrifugation demonstrated the coequilibration of most of the intracellular unesterified cholesterol with low density lysosomes. Some cholesteryl ester was also associated with low density lysosomes, although most was found in a lipid droplet fraction of very low density. Together the results indicate that in rabbit atheromatous cells, lysosomes are the site of accumulation of intracellular cholesterol in excess of that structurally associated with membranes and that both cytoplasmic droplets and lysosomes are depot sites for cholesteryl esters.

Acid Phosphatase↗
PubMed1977

Subcellular fractionation and morphology of calf aortic smooth muscle cells. Studies on whole aorta, aortic explants, and subcultures grown under different conditions.

A comparative biochemical and morphological study was made of calf aortic smooth muscle cells found in situ and grown in vitro under various conditions. Striking alterations in enzyme contents, physical properties, and morphological appearances of lysosomes, endoplasmic reticulum, plasma membranes and, to a lesser extent, mitochondria were observed upon culturing of calf aortic smooth muscle cells. These changes first appeared in cells growing out of tissue explants. They developed further upon subculturing of the cells and depended greatly on the culture conditions used. The alterations included increases in specific activities of some 5- to 25-fold of four acid hydrolases, an average ninefold increase in 5' -nucleotidase, sevenfold increase in cytochrome oxidase, and fourfold increase in neutral alpha-glucosidase in subcultured smooth muscle cells compared to aortic cells in situ. Cell fractionation studies showed significant shifts in the equilibrium densities of plasma membranes, microsomes, and lysosomes, but not of mitochondria, in smooth muscle cells growing out from explants and in subcultured cells, compared to cells isolated from intact aortas. Although the cells grown in vitro exhibited typical phenotypic features of smooth muscle cells such as abundant myofilaments and surface vesicles, alterations in the morphological appearance of the endoplasmic reticulum, Golgi apparatus, and, especially, lysosomes were observed. These results demonstrate significant differences in specific cellular characteristics and functions of aortic smooth muscle cells grown in vitro compared to aortic cells in situ.

Aorta↗
PubMed1977

Characterization of lipid-laden aortic cells from cholesterol-fed rabbits. I. Resolution of aortic cell populations by metrizamide density gradient centrifugation.

Enzymatically isolated aortic cells from control and cholesterol-fed rabbits were subjected to isopycnic density gradient centrifugation in Metrizamide. Control cells formed a single band equilibrating at a median density of 1.13 to 1.14, while cells isolated from atheromatous aortas formed two distinct bands, one equilibrating in the density range of 1.12 to 1.14 and the other occurring at a lower density of 1.03 to 1.07. Morphologically, the low density cells exhibited typical features of aortic foam cells. They were found to be greatly enriched in free and esterified cholesterol and in four lysosomal hydrolases. Further studies showed these cells to contain lipid-laden lysosomes. The high density cells from cholesterol-fed rabbits were also enriched in cholesterol and lysosomal enzymes compared to control aortic cells but not to the extent showen by the low density foam cells. While exhibiting the ultrastructural characteristics of smooth muscle cells, the cells in this fraction showed a considerable degree of morphologic and biochemical heterogeneity, suggesting the occurrence of many transition forms between normal smooth muscle cells and fully transformed foam cells.

Animals↗
PubMed1976

Analytical subcellular fractionation studies on rat liver and on isolated jejunal enterocytes with special reference to the separation of lysosomes, peroxisomes and mitochondria.

1. Enterocytes were isolated from rat jejunum and characterized morphologically. 2. Attempts to separate the enterocyte subcellular organelles, characterized by their marker enzymes, with isopycnic centrifugation were unsuccessful but good separation of peroxisomes, lysosomes and mitochondria was achieved by sedimentation through a shallow sucrose density gradient with a super-imposed inverse gradient of low-molecular-weight dextran. 3. The properties and enzyme activities of the principal subcellular organelles in rat liver cells and enterocytes were compared.

Animals↗
PubMed1974

Lysosomes of the arterial wall. IV. Cytochemical localization of acid phosphatase and catalase in smooth muscle cells and foam cells from rabbit atheromatous aorta.

Cytochemical methods for acid phosphatase and catalase were applied to atheromatous aortas from cholesterol-fed rabbits. Whole tissue, partially digested aortic slices and isolated cells were used for the study. Present in the atheromatous lesions were smooth muscle cells in all stages of foamy transformation, from virtually normal appearing smooth muscle cells to severely altered cells with pronounced lipid accumulation. The results with the acid phosphatase method show that lysosomes increase both in size and in number as the smooth muscle cells become foam cells. In normal appearing smooth muscle cells, acid phosphatase reaction product was found in stacked cisternae of the Golgi apparatus and in small vesicles located in the Golgi region and distributed throughout the cytoplasm. In foam cells, reaction product was found in membrane-limited vacuoles of varying size which typically contained membranous debris or myelin-like figures together with massive lipid deposits. No reaction was seen in "free" cytoplasmic lipid droplets lacking a surrounding membrane. These results confirm and extend previous biochemical findings indicating that, in the cholesterol-fed rabbit, the change from normal smooth muscle cell to foam cell is accompanied by marked physical and chemical changes of the lysosomes, including their progressive overloading with cholesteryl ester. Small diaminobenzidine-positive particles were present in normal smooth muscle cells and in those at all stages of foamy transformation. These particles were more frequent in foam cells, in agreement with the marked increase in catalase activity detected biochemically in these cells.

Acid Phosphatase↗