Cardiomyocytes of the left ventricle of the heart in experimental infarct and pharmacostimulation (histochemical study)

Contents and activity of lactate dehydrogenase and succinic dehydrogenase of cardiomyocytes have been studied histochemically and cytophotometrically in the left ventricle of the rabbit heart under conditions of myocardial infarction experimentally induced by alpha-tocoferol and sodium nucleinate. The substances mentioned produce a protective effect on the energic metabolism of cardiomyocytes.     

Characteristics of L-carnitine import into heart cells

L-carnitine is an essential cofactor for the transport of fatty acids across the mitochondrial membranes. L-carnitine can be provided by food products or biosynthesized in the liver. After intestinal absorption or hepatic biosynthesis, L-carnitine is transferred to organs whose metabolism is dependent upon fatty acid oxidation, such as the skeletal muscle and the heart. The intracellular transport of L-carnitine into the cell requires specific transporters and today, several of these have been characterized. Most of them belong to the solute carrier family. Heart is one of the major target for carnitine transport and use, however basic properties of carnitine uptake by heart cells have never been studied. In this paper, the transport of L-carnitine by rat heart explants has been examined and the kinetic properties of this transport determined and compared to data obtained in skeletal muscle explants. As in muscle, L-carnitine uptake by heart cells was shown to be dependent on sodium and was inhibited by L-carnitine analogues. Molecules known to interact with the skeletal muscle L-carnitine transport were studied in the heart. While trimethyl hydrazinium propionate (THP) was shown to fully inhibit the L-carnitine uptake by muscle cells, it remained inefficient in inhibiting the L-carnitine uptake by heart cells. On the other hand, compounds such as verapamil and AZT were both able to inhibit both the skeletal muscle and the cardiac uptake of L-carnitine. These data suggested that the muscle and heart systems for L-carnitine uptake exhibited different systems of regulation and these results have to be taken in consideration while administrating those compounds that can alter l-carnitine uptake in the muscle and the heart and can lead to damage to these tissues.     

New data on the tachyphylactic properties of sodium nucleinate]

Sodium nucleinate, when injected into mice in combination with killed E. coli or prodigiozan, caused a decrease in side effects produced by the vaccine or polysaccharide. The combined injection of sodium nucleinate and prodigiozan in doses, ineffective if introduced separately, was accompanied by the potentiation of their tachyphylactic action. The use of sodium nucleinate in combination with polyvinylprrolidone (hemodez) prolonged the tachyphylactic action of sodium nucleinate and increased its effectiveness. The proposed principle is supposed to be suitable for decreasing the reactogenicity of bacterial vaccines and polysaccharides.     

Sodium nucleinate increase of nonspecific macroorganism resistance to conditionally pathogenic and pathogenic microorganisms

Sodium nucleinate significantly increased the non-specific resistance of mice to E. coli O26, Ps. vulgaris, Ser. marcesens, Ps. aeruginosa, Kl. ozaenae and their associations and total resistance also accompanied by a significant decrease in the number of the bacteria in the spleen and blood, the total number of the cells in the peritoneal exudate and the number of the cells adhering to the glass (macrophages). The preparation is a low molecular RNA consisting mainly of fraction 3S and a small amount of fraction 4S. It contains 1.5 per cent of protein and 2 per cent of DNA and does not contain any polysaccharides. Repeated purification of sodium nucleinate lowering the levels of the admixtures 5 times did not change its efficacy. The low molecular RNA of the rat liver (4S) had a pronounced stimulating activity. On infection of the host stimulated with sodium nucleinate, formation of the post-infection immunity was not decreased.     

The effect of sodium nucleinate on allergic and immunological reactions

Experiments on immunized rabbits and guinea pigs indicated that sodium nucleinate (SN) was capable of weakening or entirely eliminating anaphylactic and skin reactions of delayed type hypersensitivity to repeated administration of staphyloanatoxin, APDT vaccine. The findings on patients with the infectious form of bronchial asthma and chronic rheumatism showed that sodium nucleinate attenuated reactions to the subcutaneous administration of staphylococcal and streptococcal allergens. The treatment of patients suffering from infectious-allergic bronchial asthma and rheumatism with SN resulted in the recovery of deficient T cells, T-suppressors, normalization of immunoglobulin concentrations. In children with acute glomerulonephritis sodium nucleinate normalized decreased T-suppressor cells and increased IgG and circulating immune complexes (CIC), resulting in a pronounced remission of disease. The mechanism of desensitization and elimination of CIC by SN has not been explored, however, the parameters of SN-induced immunomodulation are known rather completely. It is suggested that SN brings about accumulation in the cell of cyclic AMP which diminished membrane permeability, activates monoaminooxidase resulting in the degradation of histamine and other biogenic amines, enhances the synthesis of endogenous corticosteroids with their desensitizing properties. All these effects contribute to the elimination of delayed type hypersensitivity. The role of SN in the inhibition of delayed type hypersensitivity remains obscure.     

Potential roles of myoglobin autoxidation in myocardial ischemia-reperfusion injury.

The source(s) of reactive partially reduced oxygen species associated with myocardial ischemia/reperfusion injury remain unclear and controversial. Myoglobin has not been viewed as a participant but is present in relatively high concentrations in heart muscle and, even under normal conditions, undergoes reactions that generate met (Fe3+) species and also superoxide, hydrogen peroxide, and other oxidants, albeit slowly. The degree to which the decrease in pH and the freeing of copper ions, as well as the variations in pO2 associated with ischemia and reperfusion increase the rates of such myoglobin reactions has been investigated. Solutions of extensively purified myoglobin from bovine heart in 50 mM sodium phosphate buffer were examined at 37 degrees C. Sufficiently marked rate increases were observed to indicate that reactions of myoglobin can indeed contribute substantially to the oxidant stress associated with ischemia/reperfusion injury in myocardial tissues. These findings provide additional targets for therapeutic interventions.     

Increasing the non-specific resistance of animals to pathogenic E. coli with preparations of RNA]

Yeast RNA and sodium nucleinate considerably increased the nonsusceptibility of mice to pathogenic escherichia and typhoid salmonellae. Ineffective single nucleonate doses created an intense resistance in repeated use; prolonged application was not accompanied by the appearance of tolerance to the preparation. The principal mechanism of the induced phenomenon consisted in the intensification of the bacterial elimination and the endotoxin detoxification chiefly realized by the activity of the mobile phagocytes.     

Comparative effectiveness of immunomodulators in the therapy of rheumatic heart defects

A total of 166 patients with rheumatic heart diseases were examined. It was shown that the patients had secondary immune deficiency mainly with respect to the T-cells, which could not be eliminated with the routine therapeutic agents. The use of hemodes, decaris or sodium nucleinate in the combined therapy of such patients promoted correction of the immune deficiency and increased the treatment efficacy. Sodium nucleinate proved to be the most active.     

Alteration of lipid methylation by oleic acid in rat heart sarcolemma

Incubation of rat heart sarcolemma with the methyl donor S-adenosyl-L-[methyl-3H] methionine resulted in N-methylation of phosphatidylethanolamine and methylation of a heterogenous fraction of nonpolar lipids in the membrane. Oleic acid reduced the synthesis of N-methylated phospholipids and stimulated the methyl group incorporation into nonpolar lipids in a concentration-dependent manner. Both methylation reactions were not affected when oleic acid was substituted by methyl ester of oleic acid or by the detergents sodium deoxycholate or Triton X-100. This study suggests that the enzymatic biosynthesis of the N-methylated phospholipids may be altered by free fatty acids.     

Use of sodium nucleinate and its combinations with bacterial polysaccharides for preventing the nephrotoxic action of aminoglycoside antibiotics

Possible prevention of the nephrotoxic effect of different doses of aminoglycoside antibiotics, such as monomycin, kanamycin and gentamicin was studied experimentally on chinchilla rabbits. Substances increasing the cell resistance (sodium nucleinate, prodigiosan and pyrogenal alone and sodium nucleinate combinations with the bacterial polysaccharides) were used. It was shown that sodium nucleinate prevented nephrotoxicity of the aminoglycosides in the doses 2.5 times higher than the therapeutic ones. The combined use of sodium nucleinate with pyrogenal or prodigiosan was most effective. It prevented the nephrotoxic effect of the antibiotics in the doses 5 times higher than the therapeutic ones.     

Regulation of RNA synthesis in the rat heart in L-thyroxine toxicosis and hypothyroidism; the role of RNA-polymerases and the template activity of chromatin

It is shown that L-thyroxin applied to rats has induced in them development of pronounced cardiac hypertrophy accompanied by an increase in the total amount of nucleic acids in the myocardium (per organ) and enhancement of the RNA synthesis rate. It is confirmed by a considerable rise of the intensity of the labelled uridine incorporation into RNA without alteration of the specific radioactivity in a pool of free nucleotides and by the growth of the RNA-polymerase I activity. When L-thyroxin toxicosis lasts for four weeks and heart weight has not already increased the content of nucleic acids remains high, the rate of the label incorporation into RNA lowering down to the normal level. The activity of RNA-polymerase I is almost twice as low as that under thyrotoxicosis lasting for a week. In this case the matrix activity of chromatin tested by exogenous RNA-polymerase III of the rat gets lower. Under mercasolyl-induced hypothyrosis the heart weight decreases as well as the amount of nucleic acids, RNA synthesis intensity (by 40%) and RNA-polymerase I activity in it. The data obtained testify to the versatile effect of the thyroid hormones on RNA biosynthesis in the cardiac muscle and on the activity of both the RNA-polymerases and chromatin matrix.     

Further research on an experimental justification for the emergency prophylaxis of typhoid]

Experiments were conducted on mice. A possibility was demonstrated of express prophylaxis of typhoid fever by subcutanoues injection of the vaccine and by oral administration of sodium nucleinate, of lowering the dose by half and replacement of revaccination by sodium nucleinate alone. An increase in the titre of typhoid agglutinins and of preventive activity of the blood serum was revealed on volunteers.     

Mechanisms of attenuation of ischemic heart injury by means of a modified reperfusion

Mechanisms of attenuation of membrane injury and metabolic impairments in postischemic cardiomyocytes have been studied on a model of ischemic and reperfusion stress of rat heart using a modified early reperfusion. Optimization of the reperfusion infusate composition augmented recovery of cardiac pump and contractile function. This was accompanied by reduced release of lactate dehydrogenase activity and systems generating short-living reactive oxygen species into myocardial effluent and was associated with more efficient oxidative metabolism recovery and decreased losses of intracellular total creatine and amino acids pools. The results indicate perspectives of postischemic functional and metabolic myocardial injury correction by means of the controlled reperfusion.     

Intensification of antibacterial and antiviral nonsusceptibility and of the immune response with an officinal RNA preparation]

Sodium nucleinate increased essentially the insusceptibility of mice to pathogenic escherichia, strain O26, Pr. vulgaris, Ps. aeruginosa, Ser. marcescens, and produced a total stimulating effect on the nonspecific bacterial resistance; analogous stimulating activity was found in the homologous low polymeric RNA from the liver. Sodium nucleinate intensified the insusceptibility of the animals to the tick-born encephalitis and encephalomyelitis viruses, and increased the antibody-forming cells count. The side-effect of heat-inactivated vaccine from pathogenic escherichia was reduced in animals inoculated with sodium nucleinate preliminarily.     

Histochemical studies of some myocardial oxido-reductive enzymes after experimental beta-adrenergic blockade with propranolol

Summary Histochemical studies of some myocardial oxido-reductive enzymes after a beta-adrenergic blockade with propranolol have been carried out. Succinate, isocitrate and glucose-6-phosphate dehydrogenases did not indicate any changes in activity, whereas the changes in reaction intensities concerning NADH and NADPH tetrazole reductases and glutamate dehydrogenase have rather a transitory and reversible character. Only lactate dehydrogenase showed an increase in the enzymatic activity which speaks for an increase in the glycolysis process in the heart muscle. In the light of our own presented research results we assume that the experimental beta-adrenergic blockade of the heart muscle in rats does not evoke more important enzymatic changes which are noticeable in histochemical microscope examination.     

Effects of potassium deficiency on potassium,polyamines and amino acids in mouse tissues

Sexual dimorphism in potassium content was found in plasma, kidney, heart and skeletal muscle of CD1 mice. We observed that feeding mice with a K(+)-deficient diet had an uneven and gender-dependent effect on organ weight and tissue potassium concentrations. Treatment produced a marked decrease in plasma, pancreas and skeletal muscle K(+) levels in both sexes, and a reduction in kidney, liver and heart potassium concentrations in females. Moreover, K(+) deficiency produced a 2-3-fold increase in the concentrations of cationic amino acids, such as arginine and lysine in both heart and skeletal muscle of the two sexes, a slight increase ( approximately 37%) in renal arginine in the male mice. The concentrations of these amino acids in plasma and other tissues in both sexes remained unaltered. Polyamine levels in heart, liver, skeletal muscle and pancreas from male and female mice were not affected by K(+) deficiency. However, in the male kidney potassium deficiency was accompanied by an increase of putrescine and spermidine concentration, and a reduction of putrescine excretion into the urine, even though renal K(+) concentration was not significantly affected and ornithine decarboxylase activity was dramatically decreased. The general lack of correlation between tissue potassium decrease and the increase in organic cations suggests that it is unlikely that the changes observed could be related with an attempt of the tissues to compensate for the reduction in cellular positive charge produced by the fall in K(+) content. The mechanisms by which these changes are produced are discussed, but their physiological implications remain to be determined.     

Histochemical studies of some myocardial oxido-reductive enzymes after experimental beta-adrenergic blockade with propranolol.

Histochemical studies of some myocardial oxido--reductive enzymes after a beta--adrenergic blockade with propranolol have been carried out. Succinate, isocitrate and glucose-6-phosphate dehydrogenases did not indicate any changes in activity, whereas the changes in reaction intensities concerning NADH and NADPH tetrazole reductases and glutamate dehydrogenase have rather a transitory and reversible character. Only lactate dehydrogenase showed an increase in the enzymatic activity which speaks for an increase in the glycolysis process in the heart muscle. In the light of our own presented research results we assume that the experimental beta--adrenergic blockade of the heart muscle in rats does not evoke more important enzymatic changes which are noticeable in histochemical microscope examination.     

Removal of the N-terminal extension of cardiac troponin I as a functional compensation for impaired myocardial beta-adrenergic signaling

Although beta-adrenergic stimuli are essential for myocardial contractility, beta-blockers have a proven beneficial effect on the treatment of heart failure, but the mechanism is not fully understood. The stimulatory G protein alpha-subunit (Gsalpha) couples the beta-adrenoreceptor to adenylyl cyclase and the intracellular cAMP response. In a mouse model of conditional Gsalpha deficiency in the cardiac muscle (Gsalpha-DF), we demonstrated heart failure phenotypes accompanied by increases in the level of a truncated cardiac troponin I (cTnI-ND) from restricted removal of the cTnI-specific N-terminal extension. To investigate the functional significance of the increase of cTnI-ND in Gsalpha-DF cardiac muscle, we generated double transgenic mice to overexpress cTnI-ND in Gsalpha-DF hearts. The overexpression of cTnI-ND in Gsalpha-DF failing hearts increased relaxation velocity and left ventricular end diastolic volume to produce higher left ventricle maximum pressure and stroke volume. Supporting the hypothesis that up-regulation of cTnI-ND is a compensatory rather than a destructive myocardial response to impaired beta-adrenergic signaling, the aberrant expression of beta-myosin heavy chain in adult Gsalpha-DF but not control mouse hearts was reversed by cTnI overexpression. These data indicate that the up-regulation of cTnI-ND may partially compensate for the cardiac inefficiency in impaired beta-adrenergic signaling.     

Comparative effectiveness of immunomodulators in the therapy of bronchopulmonary diseases

One hundred and fifty-one patients with bronchopulmonary diseases were examined and it was shown that they had secondary immune deficiency mainly in the T-cells which could not be recovered with the routine therapeutic agents. The use of hemodez, levamisole or sodium nucleinate in the combined therapy promoted correction of the immune deficiency and increased the treatment efficacy. Sodium nucleinate proved to be the most efficient.     

RNA-induced intensification of antibacterial resistance and aggravation of infection

The injection of yeast total RNA, transfer RNA or sodium nucleinate into the organism of experimental animals induced the development of non-specific resistance to pathogenic salmonellae, staphylococci and escherichiae 4-6 hours after the administration of the preparations; this resistance persisted during several days. The content of serum lysozyme rose and interferon was induced in the stimulated animals, but the state of resistance was not transferred with serum. It was due to mobile phagocytes the number of which increased considerably and so did their digestive activity. Simultaneous administration of RNA and pathogenic salmonellae and staphylococci was accompanied by aggravation of infection and acceleration of the lethal outcome. The mechanism of this phenomenon consists in the acceleration of proliferation of the microorganisms and in the selection of their virulent clones under the effect of RNA which was demonstrated in experiments in vivo and in vitro. It is believed that endogenous nucleic acids participate in the development of the natural infectious process, in bacterial complications of viral infections and in autoinfection during radiation sickness.