[Features of the biochemical action of paraquat on oxidative deamination of biogenic amines and other nitrogen compounds].

Intoxication of rats with the herbicide paraquat (1,1-dimethyl-4,4-bipyridilium dichloride) was accompanied by accumulation in lungs, brain, heart, liver or kidney of malonic dialdehyde (MDA) (the compounds reacting with 2-thiobarbituric acid), indicating that the intoxication stimulated lipid peroxidation (LPO) in biomembranes. Treatment of the intoxicated rats with the antioxidant diludin (2,6-dimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridine) or with the nucleophilic reagents sodium ascorbate or thiosulphate normalized the content of MDA in lungs, brain, heart, liver or kidney demonstrating the reversibility of the LPO stimulation caused by paraquat. On incubation of mitochondrial fractions of homogenates of lungs, brain, heart, liver or kidney of the intoxicated rats (as compared with the corresponding fractions from the intact animals) a decrease was noted in deamination of the substrates of monoamine oxidases serotonin, tryptamine, benzylamine, tyramine; at the same time, deamination of glucosamine and gamma-aminobutyric acid was increased and deamination of putrescine and L-lysine appeared.

[Activation of lipid peroxidation processes in chronic ischemic heart disease].

The content of lipid peroxidation products--hydroperoxides with conjugated double bonds and fluorescent compounds, which are formed on interaction of primary lipid peroxidation products and proteins, considerably increases in blood plasma of patients suffering from coronary heart disease. Treatment with combined vitamins E and C enables the blood plasma lipid peroxidation products to be decreased to a far greater extent as compared with conventional therapy.

[Thyroid dysfunction and disorders in deamination of nitrogenous compounds in experimental atherosclerosis].

A decrease in monoamine deamination with simultaneous appearance of cadaverine deaminating activity in the mitochondrial fractions of the rabbit liver, brain and heart was more noticeable under conditions of hypothyroidism combined with hypercholesterolemia developing in the presence of normal function of the thyroid. A decrease in monoamine deamination, the appearance of cadaverine deaminating activity and a significant increase in AMP deamination were observed in the mitochondrial fraction of the rabbit heart muscle under conditions of hyperthyroidism.

[Disorders of the deamination of nitrogenous compounds in the heart muscle in experimental atherosclerosis].

The development of alimentary hypercholesterolemia in rabbits (confirmed by morphometric, electrophysiological and biochemical data) was accompanied by a decrease of the serotonin, benzylamine and tyramine deamination rates in heart muscle mitochondria. At the same time a qualitatively new reaction of cadaverine deamination could be seen in the mitochondria. The data obtained suggest that impairment of deamination of the nitrogenous compounds in atherosclerosis may be due to reversible qualitative modification (transformation) of mitochondrial monoamine oxidase activity.

[Normalization of impairments in deamination of nitrogen compounds in experimental hypercholesterolemia].

Appearance of cadaverine deaminating activity in mitochondrial fractions of liver and kidney of rabbits with experimental alimentary hypercholesterolaemia was prevented by an antioxant diludin (2,6-dimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridine) which also decreased the abnormally elevated AMP-deaminating activity and elevated the decreased monoamine oxidase activity (substrates: serotonin, benzylamine, tyramine). In heart and brain tissues as compared with liver and kidney the impairments caused by hypercholesterolaemia and the normalizing effect of diludin were less distinct. The effects of diludin could be reproduced by nucleophylic reagents sodium thiosulphate or ascorbate.

[Mechanism of disturbances in the deamination of nitrogenous compounds in experimental hypercholesterolemia and atherosclerosis].

Experimental alimentary hypercholesterolaemia in rabbits caused not only a decrease in deamination of monoamines (serotonin, benzylamine, tyramine) in liver, brain, kidney and heart mitochondrial fractions but also an appearance in these fractions of a qualitatively new reactions, namely that of cadaverine deamination, which was occasionally accompanied by stimulation of AMP deamination. In mitochondrial fractions from liver tissue obtained by autopsy in cases of ischemic heart disease accompanied by atherosclerosis, as compared with the corresponding fractions from the liver of persons who died in accidents and in whom no distinct morphological manifestations of atherosclerosis could be noted, there was observed a decrease in deamination of serotonin or tyramine (by 52% and 63%), appearance of cadaverine deamination (Vmax constitutes 35% of the Vmax value for serotonin deamination in the same fraction (and stimulation) 2-fold) of AMP deamination. The impairments in deamination of the nitrogenous compounds in experimental hypercholesterolaemia and in atherosclerosis are apparently due to qualitative alteration (transformation) in catalytic properties of mitochondrial monoamine oxidases.