Sz.I. Varga

A comparative study of some more important experimental animal peroxide metabolism enzymes

1. We have studied and compared the peroxide metabolism enzymes (SOD, P and C) of the main organs of fresh-water mollusc, chicken, mouse, guinea-pig, rabbit, cat and dog. 2. The liver exhibited the highest SOD activity. The enzymatic activities of the organ homogenates of the guinea-pig stand out in comparison with the values for the other homogenates examined. 3. The liver, kidney and total brain homogenates of the chicken and the vertebrates display no, or only a very low P activity. The highest P activities were measured in the haemolysates. 4. The C and SOD values exhibit a certain parallelism. 5. The peroxide metabolism enzyme activities calculated by utilizing the protein measurements permit the establishment of a more realistic enzymatic activity.

Examination of the role of oxygen free radicals in bronchial asthma in childhood

The antioxidant enzyme activities, the lipid peroxidation level, the parameters of glutathione metabolism, and the proportion of haemoglobin oxidation products were determined during the symptom-free period of childhood bronchial asthma. A decreased catalase activity and a significantly reduced glutathione instability were demonstrated as compared to the controls. The results indicate that antioxidant protection of the haemoglobin molecule in asthmatic children is considerably decreased.

In vivo effects of paraquat on some oxidative enzymes of mice

Abstract 1. By means of a comparison with untreated controls, a study was made of the effects of LD50 and LD100 of paraquat in vivo on the peroxide metabolism enzymes (superoxide dismutase, peroxidase and catalase), on the tissue lipid peroxidation, and on the microsomal cytochrome P-450 concentrations of the main organs. 2. The results reveal that the enzymes and the tissue properties compared are influenced by the herbicide in different manners, depending on its concentration. 3. The effect is connected first of all with the redox properties of paraquat, which in mice acts either as an electron donor or as an electron acceptor, depending on its concentration.

Some new data to the toxicological effects of paraquat and the therapy

1. Substances previously tested therapeutically were studied to obtain evidence on the pathomechanism in mice of paraquat, the active ingredient of Gramoxon, connected with the radicals formed from molecular oxygen, and also to extend the therapeutic possibilities. 2. The effects of these substances were assessed on the basis of the 72-hr survival rate and the percentage ratio of the wet lung weight to the overall body weight. 3. Other toxicological parameters too were followed. 4. Our present investigations indicate that, in agreement with our earlier results, besides reduced glutathione and ascorbic acid, vitamin E and C-ase are of the greatest importance from the aspect of the protection against paraquat toxicity. 5. In addition to those listed, other materials too, e.g. antifibrotic substances, naturally possess considerable detoxicating properties too.

Simple method for the measurement of antioxidants

Washed red blood cells from preserved blood were used to elaborate a method suitable for the examination of red blood cell deformability and for the detection of changes in oxidative stress, i.e. for the determination of lipid peroxidation and antioxidant enzyme activity changes. The oxidative stress was induced by treatment of red blood cells with hydrogen peroxide.

The effects of Oradexone and Ambroxol pretreatment on the oxidative sensitivity of the red blood cells in preterm infants

The antioxidant enzyme activities and lipid peroxidation in the red blood cells of cord blood were investigated and compared at different gestation times in preterm and full-term neonates, with and without pretreatment of the pregnant mothers with Oradexone (Dexamethasone) or Ambroxol. Administration of the two drugs not only stimulated the lung surfactant system, but also exerted favourable effects on the antioxidant enzyme activities while the lipid peroxidation was decreased.

Changes induced by Gramoxon® in tissue phospholipids and phospholipid fatty acids in mouse and guinea-pig

Following administration of the LD50 or the LD100 of Gramoxon (PQ), the phospholipids (PL) of the lung, liver and kidney were separated and both the PLs and the fatty acids isolable from them were examined quantitatively. The different doses of PQ caused different changes of the saturated and unsaturated fatty acids in the various organs. The changes in the PL unsaturated fatty acids point to PQ-induced lipid peroxidation enhancement and membrane damage.

Enhancing effect of aminotriazole on paraquat toxicity in vivo

Abstract 1. 1. The lethal joint action of aminotriazole and the LD50 of paraquat was observed in experimental mice. 2. 2. The molecular mechanism of the synergistic effect may be explained on an experimental basis by the extensive changes in the lipid peroxidation and the cytochrome P-450 activities. 3. 3. Both substances act on the other enzyme activities examined, primarily the catalase activity, in accordance with the literature evidence.

Comparison of peroxide metabolism enzymes in organs of congenic mice

1. A study was made of the SOD, P and C activities and the protein contents of the tissue homogenates in the five most important organs of six inbred mouse strains. 2. From the results of comparative examinations it emerges that the above PMEs exhibit substantial differences in the various inbred mouse strains. 3. Accordingly, only pure inbred mice or rats raised under identical conditions can be used for PME comparisons. 4. The examinations also reveal that the PME levels of the inbred strains are genetically determined.

The effect of light on the toxicity of paraquat in the mouse

The role of light is known to be important in the herbicidal action of paraquat, the active ingredient of Gramoxon. Experiments were therefore performed to establish whether illumination influences paraquat toxicity in some way in mice. Besides the 72-hr survival rate, studies were made of the body weight/lung weight ratio, the antioxidant enzyme activity and the lipid peroxidation in mice treated with the LD50 of paraquat and kept in the dark or under illumination. All of the measured parameters indicate that illumination enhances the toxic properties of paraquat in mice.