Maria Koter

Damage of erythrocyte by phenoxyacetic herbicides and their metabolites

The molecular background of toxic properties of phenoxy herbicides for humand and animals is insufficiently studied. In this study, damage parameters (hemolysis, hemoglobin oxidation, and lipid peroxidation) were measured in human erythrocytes exposed to several commonly used herbicides from this group (2,4-D, 2,4,5-T, and MCPA) and their phenolic metabolites. For all parameters studied the impact of herbicide metabolites was stronger than that of herbicides themselves. The extent of hemolysis was dose-dependent and also depended on the solvent used. Whereas compounds with methyl groups were more potent in the methemoglobin formation assay, compounds with chlorine substituents caused higher lipid peroxidation.

Damage to the structure of erythrocyte plasma membranes in patients with type-2 hypercholesterolemia

BACKGROUND Hypercholesterolemia may decrease the deformability of red blood cells which impairs their hemorheological behavior and promotes atherosclerosis. The study involved 60 hypercholesterolemic patients and 30 healthy individuals as the control group. METHODS The membrane fluidity of erythrocytes was estimated by a spin-label method (5-doxylstearic acid (5-DSA)). The ratio of weakly to strongly (W/S) immobilized residues of erythrocyte membrane-bond maleimide-tempo spin label was studied in oxidative damage to membrane protein. Damage to erythrocyte proteins was also indicated by means of Na(+) K(+) ATPase activity. RESULTS The membranes of hyperlipidemia (hlp) patients contain larger concentrations of cholesterol 2.16+/-0.24 than do those of the normolipemic individuals 0.31+/-0.24 (P<0.001). The level of Na(+) K(+) ATPase in the erythrocyte membrane from the control group was higher 103.4+/-1.3 (nmolPi/(mgproteinsh)) than in the patient group 93.6+/-3.2 (nmolPi/(mgproteinsh)) (P<0.001). The order parameter S 5-DSA in the control group was 0.745+/-0.009 and in hlp patients was 0.755+/-0.009 (P<0.001). The W/S ratio in the control group amounted to 2.00+/-0.09 and in the hlp patient group was 2.50+/-0.11 (P<0.001). CONCLUSION Type-2 hypercholesterolemia causes changes in the structure and fluidity of erythrocyte plasma membranes since the excess of cholesterol affects the normal rheology of blood through its interaction with erythrocytes. It also impairs the function and structure of plasma membrane proteins.

THE BIOSTIMULATORY EFFECT OF RED LASER IRRADIATION ON PIG BLOOD PLATELET FUNCTION

The molecular mechanisms of laser‐induced changes in the cell structure and function are not well known. The authors examined the effects of low‐power laser irradiation on unnucleated pig blood platelets. The obtained results showed that laser irradiation (1–5J) caused in blood platelets lipid peroxidation (measured as thiobarbituric acid reactive substances) and super‐oxide anion generation, concomitant with the release of adenine nucleotides and proteins from platelets. The maximum platelet response to laser irradiation was observed when doses of 1.8–2J were used. Our results indicate that red laser irradiation induces: (1) platelet secretory process and the release of substances stored in the specific granules (adenine nucleotides, proteins); and (2) lipid peroxidation partly due to stimulation of endogenous arachidonate and production of its metabolites reacting with thiobarbituric acid.

Does Thermotolerance Occur in Human Red Cells

Osmotic fragility and autohemolysis were used as endpoints in the measurement of damage to the plasma membrane in human erythrocytes, after single or double heat treatments. Injury recorded above 46 degrees C, and the induction of thermotolerance in the enucleate cells after a primary heat treatment of 44 degrees C for 15 min, indicates that the plasma membrane plays an important role in heat injury and in thermotolerance.

Changes in erythrocyte membranes after fractioned hyperthermia

The structural changes in erythrocytes membranes were examined before and after the second heat shock of erythrocytes. Electrophoretic separation of protein erythrocyte membranes for cells incubated at 48.5°C was different from control i.e. from erythrocytes incubated at 37°C. No quantitative or qualitative changes were spotted in comparison with protein membranes isolated from the erythrocytes following single or double heat shock.

EFFECTS OF GAMMA- AND X-IRRADIATION ON NUCLEOTIDES OF LYMPH NODES.

SummaryCalf lymph nodes were subjected to gamma- and x-radiation, and the following compounds were estimated by column chromatography: NAD, CMP, AMP, NADP, GMP, UMP, ADP, UDP, ATP, GTP, UTP.Irradiation of lymph nodes with x-rays was carried out using Scandia apparatus, Type TA 310. Energy doses were estimated by x-ray chamber and calculated theoretically. Maximal increase of AMP, ADP, ATP and sum of adenine nucleotides of about 150 per cent (control 100 per cent) was observed at about 1·5 krads.Irradiation with gamma-rays from a 60Co source (Gamma cells-200) was performed in the range of 0·3 to 40 krads. Doses were estimated, using a Fricke dosemeter and also calculated theoretically. For the dose of about 2 krads the maximum increase of all adenine nucleotides of about 150 per cent was observed. Other nucleotides increased simultaneously.It is suggested that the observed effects are due to the release of enzymes from lysosomes, beginning at about 2 krads.