The influence of N-[imino(1-piperidinyl)methyl]guanidine and N-[imino(4-morpholinyl)methyl]guanidine on citrate content,activities of aconitase and citrate synthase in rats exposed to cerebral ischemia-reperfusion

The effect of guanidine derivatives on citrate content and activity of aconitate hydratase and citrate synthase have been investigated in rats with cerebral ischemia-reperfusion. Administration of N-[imino(1-piperidinyl)methyl]guanidine and N-[imino(4-morpholinyl)methyl]guanidine resulted in changes of specific activities of aconitase and citrate synthase towards control values. Under these conditions the citrate level considerably decreased versus rats with untreated ishemia-reperfusion. Administration of these biguanidines compounds also decreased the degree of DNA fragmentation, which was markedly increased in rats with ischemia-reperfusion. The dose-dependent effects of guanidine derivatives suggest that they exhibit not only antioxidant but also prooxidant effects.     

Antihypoxic effects of quinones connected with restoration of electro-transport and function of the respiratory chain of the isolated rat heart

The effect of hypoxia of middle severity (H50) has been investigated on the contractile activity, oxidative metabolism and bioenergetic function of the myocardium in the isolated rat heart. It has been shown that differences in the functional-metabolic parameters sensitivity in the resistant and non-resistant to hypoxia animals are defined by the primary utilization of different pathways of substrates oxidation--the succinate-oxidative pathway of oxidation or the NADH-oxidative pathway, correspondingly. It is possible to correct the early hypoxic injuries of the electron-transfer function of the myocardium respiratory chain at the NADH-CoQ region (the first enzyme complex) with the help of quinones (vitamin K3, hydroquinone). The mechanism of this correction depends on the donor-acceptor properties of these compounds and it is the same both in the myocardium of the isolated heart and in the isolated mitochondria. Vitamin K3 is recommended to be utilized on the early stages of hypoxic injuries in myocardium as an antihypoxant of the energized type.     

Purification and some properties of skeletal muscle sarcolemma Ca2+-ATPase]

Ca2+-ATPase of skeletal muscle sarcolemma has been isolated and purified. It is prepared from salt extract of sarcolemma by ammonium sulfate fractionation and further purified by gel chromatography on Sepharose 4B. The purity of preparations was evaluated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. It has been shown that Ca2+-ATPase possesses the same mobility as skeletal muscle myosin under gel chromatography on Sepharose 4B and the same mobility as myosin heavy chains in sodium dodecyl sulfate--polyacrylamide gel electrophoresis. Membrane protein binds to rabbit skeletal muscle actin, and this complex dissociates by ATP. Interaction with actin does not change Ca2+- or Mg2+-stimulated ATPase activity. Enzyme has only one pH optimum at 7,0-7,6. Membrane protein is highly specified to calcium--ATPase activity in the presence of Mn2+ is 10% and in the presence of Sr2+, Mg2+ or Co2+ are 3-5% of the activity in the presence of Ca2+. Other nucleoside triphosphate (UTP and ITP) are hydrolyzed at lower rates than is ATP.     

Role of the lymphatic system in the transport of biologically active substances in shock of various etiologies

The content of histamine, serotonin, adrenaline and noradrenaline in the thoracic and lymphatic duct lymph and blood as well as absolute quantity of lymph transported biogenic amines and mediators into the general circulation were studied on 68 dogs during anaphylactic and endotoxin shock (ASh and ESh, respectively). Both ASh and ESh were accompanied by considerable changes in the hemodynamics, lymph circulation, content of biologically active substances in lymph and blood and in their lymph transport to the blood stream. The most profound and early changes in the content of biologically active substances during ASh and ESh were found in the lymph, which shows an important role of the lymphatic system in their resorption and transport from organs and tissues into the general circulation.     

The effect of biguanide derivatives on antioxidant status during the development of oxidative stress

The intensity of free radical processes, activity of antioxidant enzymes (superoxide dismutase, catalase), and the content of low molecular weight antioxidants (reduced glutathione, citrate) in skeletal muscle and liver from rats with experimental rheumatoid arthritis administered with biguanide synthetic derivatives (2,4-dicarbomethoxyphenyl-biguanide and 4-methyl-phenyl biguanide) selected by Prediction of Activity Spectra for Substances (PASS), a computer program for the prediction of biological activity, were studied. The observed changes in the studied parameters toward the reference values under the effect of tested compounds can be explained by their antioxidant and protective properties during pathology, which are accompanied by oxidative stress. The results can be used for the development of new methods for the prevention and treatment of rheumatoid arthritis.     

Effect of culture medium components on the biosynthesis of acid ribonuclease by Penicillium brevicompactum cultures]

The effect of different ingredients of the nutrient medium on the synthesis of acid ribonuclease by the culture Penicillium brevi-compactum was studied. The synthesis of RNase reached maximum on the medium containing glucose, pepton, soya bean flour, ammonium sulphate. An excessive content of phosphate in the medium decreased the RNase synthesis. An optimal medium for the synthesis of the enzymes was developed and recommended.     

Cathepsin D activity in splenocytes in relation to Shigella virulence in an experiment

The overtime study of changes in the activity of cathepsin D, a lysosomal enzyme, in the splenocytes of CBA mice after their infection with virulent and avirulent Shigella strains of the same origin and with the same antigenic structure has been made. As the result of two months of observations, changes in the activity of this enzyme in the cytoplasmic and lysosomal cell fractions have been found to occur in phases. The activity of cathepsin D has been shown to depend on the virulence of Shigella strains used for inoculation. Virulent Shigella strains induce the pronounced and prolonged activation of the enzyme in the lysosomes, as well as in the cytoplasm. The latter phenomenon is probably indicative of the pathological labilization of the lysosomal membranes, induced by the virulent culture. Avirulent Shigella strains induce only the transient activity of the enzyme in the lysosomes without any essential changes in the permeability of their membranes. These data point to the possibility of differentiating virulent and avirulent Shigella strains by the determination of the enzymatic activity of splenocytes in infected animals.