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Biomedical subjects

W Leyko

Publications and source records attributed to W Leyko.

At least 55 records · Page 3Linked to original sources
PubMed1980

Aging of the erythrocyte. I. Increase in the microviscosity of cell interior as determined by the spin label method.

By means of the spin labelling technique changes in the microviscosity of the cell interior of density-seperated bovine red blood cells were estimated. An increase in the rotational correlation time of the Tempamine spin label indicated an increase in the microviscosity of the red blood cell interior during in vivo aging. This increase is apparently due to alterations in the electrolyte content and may influence the course of diffusion-limited reactions in the cell.

Animals↗
PubMed1980

Superoxide dismutase and radiation-induced haemolysis: no benefit of its increased content in red cells.

The sensitivity of human erythrocytes with normal and increased activity of superoxide dismutase (SOD) was compared under different types of oxidative stress. Red blood cells with increased SOD activity were more resistant to haemolysis induced by photoactivated riboflavin but no more resistant to radiation-induced haemolysis and acetylphenylhydrazine stress. These results indicate a negligible role of O(2) in mediation of the haemolytic action of ionizing radiation.

Cobalt Radioisotopes↗
PubMed1979

A comparative characterization of cytosolic superoxide dismutase/(SOD) from hog liver and erythrocytes.

1. Conditions of preparation and purification of superoxide dismutase from hog liver and erythrocytes were established. 2. The enzymes from both tissues were compared in respect to electrophoretic mobility, pI value, amino acid composition and spectrophotometric profiles and some differences were observed. 3. Conditions of enzyme dissociation were elaborated and molecular weights of subunits obtained from both kinds of SOD were found to be approx. 16,000. 4. Effect of heat and pH on the enzyme activity were tested. Both enzymes exhibited a relative thermostability.

Amino Acids↗
PubMed1979

A spin-label study of the effect of gamma radiation on erythrocyte membrane. Influence of lipid peroxidation on membrane structure.

Gamma-irradiation of bovine erythrocyte membranes (0.1-4 Mrad) resulted in a decrease in the degree of order of membrane lipids, as measured by spin-labelled fatty acid esters, at the depth of C12 but not at the depth of C5. Dose dependence of this phenomenon corresponded to dose dependence of malondialdehyde formation in the membranes. On this basis a mechanism for the effect of lipid peroxidation on the membrance structure is proposed. Membrane proteins underwent radiation-induced conformational transitions revealed by maleimide spin label which could be also connected with lipid peroxidation.

Animals↗
PubMed1978

Down syndrome - transferrin parallels plasma iron changes.

The transferrin level was studied in patients with simple trisomy 21 and with Robertsonian unbalanced translocations 21/22 and 21/14. In all these groups of patients, known to have significantly lowered plasma iron levels, the transferrin levels were found to be decreased with respect to the control group.

Adolescent↗
PubMed1977

Changes of adenine nucleotides content and release reaction of human blood platelets following gamma irradiation.

The aim of this work was to examine the effect of gamma irradiation on the energy metabolism and physiological functions of blood platelets. Blood platelets were irradiated with a 60Co-source in the range of 0.5--8.0 krad. Before and after irradiation, the free nucleotide content of platelets and the ability of platelets to perform their hemostatic functions (the release reaction with thrombin) were determined. The obtained results demonstrated that: 1. ATP, ADP and AMP content reached minimum values at 1.5--2.0 krad. 2. The ability of platelets to perform the release reaction correlates with the ATP level at doses of 1.5--2.0 krad. At higher doses (6.0--8.0) disturbances of the release reaction, indicating damage to the platelet plasma membranes, were observed.

Adenine Nucleotides↗
PubMed1977

Effect of hyperoxide radicals on bovine-erythrocyte membrane.

1. Bovine erythrocytes exposed to the action of an enzymic source of hyperoxide radicals (hypoxanthine + xanthine oxidase) exhibited hemolysis, which was prevented by the presence of hyperoxide dismutase. 2. Exposing bovine erythrocyte membranes to the source of hyperoxide radicals resulted in a decrease of (Mg2+ + Na+ + K+)ATPase activity which could be partially prevented by addition of hyperoxide dismutase. 3. The damage observed to erythrocyte membranes under the conditions applied is ascribed to toh formed in the Haber and Weiss reaction since a protection by OH scavengers was also observed.

Adenosine Triphosphatases↗