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Biomedical subjects

L Skoza

Publications and source records attributed to L Skoza.

15 recordsLinked to original sources
PubMed1984

Protective effect of interferon inducers against hyperoxic pulmonary damage.

Interferon inducers, poly I:poly C, endotoxin, hepatic RNA, and Tilorone, were administered to rats at different time points in relation to the onset of hyperoxic exposure (O2 greater than 97%). All interferon inducers tested significantly reduced the mortality of rats when compared with the control groups. In hyperoxia alone, malondialdehyde, a product of lipid peroxidation, was significantly increased and the microsomal enzyme NADPH cytochrome c reductase decreased as measured in the whole lung. With the administration of either endotoxin or poly I:poly C these two parameters remained within the range of control values. These data suggest that the administration of interferon inducers protects against hyperoxic microsomal damage. After the administration of these interferon inducers with or without hyperoxia the increased activity of heme oxygenase and marked reduction of the heme content of microsomes were demonstrated. Since cytochrome P-450 and b5 are the major hemoproteins of microsomes and the known source of oxygen-free radical generation, the results obtained in this study appear to indicate that the depression of the hemoprotein of microsomes by the administration of interferon inducers may be largely responsible for the protective effects of these agents against hyperoxia.

Animals↗
PubMed1980

Lysosomal enzymes in experimental diabetic cardiomyopathy.

The present study examines the role of cardiac lysosomal enzymes in the pathogenesis of the cardiomyopathy that develops in genetically diabetic C57BL/KsJ db+/db+ mice. Db+/db+ mice and littermate controls were sacrificed as age-matched pairs between 5-26 weeks of age. C57BL/6J ob/ob mice and littermates served as other controls. The hearts were excised, homogenized, and the following enzymatic activities measured: N-Acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucosaminidase, aryl sulphatase, alpha-mannosidase, alpha-glucosidase, beta-galactosidase, beta glucosidase, total p-nitrophenyl phosphatase, acid phosphatase and 5'-phosphodiesterase type IV. There is a progressive decrease in cardiac lysosomal enzyme activities of db+/db+ mice for the period 5-21 weeks of age. All enzyme activity is depressed significantly during the 9-21 week interval with beta-glucuronidase, aryl sulphatase and beta-glucosidase decreased about 40-50%. The decrease in lysosomal enzyme activity can explain the accumulation of large residual bodies and interstitial material in the myocardium of the db+/db+ animals

Acetylglucosaminidase↗
PubMed1979

Demonstration of a protease inhibitor in the cornea.

Sequential extraction of bovine corneal homogenates with aqueous 0.154M NaCl, 0.5M NaCl and 3M guanidine HCl revealed the presence, in the two sodium chloride extracts, of trypsin inhibitory factors. Upon gel-filtration chromatography of the o.5M NaCl soluble corneal material on Sephadex G-75, two peaks with trypsin inhibitory activity were resolved. One peak was eluted in the void volume, whereas a second peak had mobility corresponding to a molecular weight fraction much lower than, and therefore distinct from, alpha 1-antitrypsin inhibitor. The possible implication of this inhibitory factor in the pathogenesis of corneal ulceration is briefly discussed.

Amidohydrolases↗
PubMed1976

Stable thiobarbituric acid chromophore with dimethyl sulphoxide. Application to sialic acid assay in analytical de-O-acetylation.

With dimethyl sulphoxide instead of butanol in the thiobarbituric acid assay for sialic acid, a non-fading chromophore with lambdamax. = 549 nm was produced in a homogeneous solution, allowing dilution of the test mixture in case of high colour yield. This test adapted well to studies on alkaline de-O-acetylation. Bovine and rat submaxillary mucins, and rabbit Tamm-Horsfall urinary sialoproteins contain O-acetyl isomers of neuramine acid that are resistant to the thiobarbituric acid assay. Alkaline de-O-acetylation converted resistant O-acetylneuraminic acid into thiobarbituric acid-reactive sialic acid, and such conversion paralleled de-O-acetylation as measured by the ferric hydroxamate method. The colour increment was similar when the alkaline treatment of bovine submaxillary mucin either preceded or followed the acid hydrolysis. Only alkaline preptreatment was effective with rat submaxillary mucin. By selecting optimal conditions for alkaline de-O-acetylation, O-acetyl isomers can be accurately assessed by the thiobarbituric acid assay.

Acetylation↗
PubMed1969

Glomerular sialoprotein.

The high content of sialic acid in the glomerulus is associated with the cell membrane of epithelial cells lining the basement membrane. Whereas enzyme studies indicate that sialic acid is a determinant of the nephritogenic antigen, the physicochemical properties of this nephritogenic glycoprotein suggest that sialic acid may have an important role in the filtration mechanism.

Animals↗
PubMed1969

Partial purification and properties of a plasminogen activator from human erythrocytes.

The lysis time of euglobulin clots made with whole blood (plasma and red cells) was very much shorter than that of clots made with plasma alone, indicating a fibrinolytic component in red cells. A plasminogen activator was found in the stroma-free hemolysate, and proteolytic activity was found in the stromal fraction. The plasminogen activator, purified by using diethylaminoethyl-cellulose (DEAE-cellulose) in a batch procedure followed by column chromatography, was called erythrokinase (EK). On preliminary characterization, EK appears to activate human and bovine plasminogen in a manner similar to urokinase (UK), as determined by fibrinolytic and caseinolytic assays. The two enzymes can be separated by DEAE chromatography and acrylamide-gel electrophoresis, however, and they hydrolyze acetyl-L-lysine methyl ester and benzoyl arginine methyl ester at different rates.

Electrophoresis↗