The effect of strophanthin following administration of homocardiac antigen to animals with experimental myocardial infarct]

A study was made of strophanthin sensitivity and hemodynamic effect of glycosidein immunization of rabbits with a homocardiac antigen on the 1st, 3rd and 5th days after the reproduction of myocardial infarction. The titre of anticardiac autoantibodies proved to decrease on the 10th day after the ligation of the coronary artery, and also there was a sharp reduction of strophanthin sensitivity by the values of the minimal lethal dose and the toxic one (causing cardiac arrhthmia). Changes in strophanthin tolerance under conditions of administration of the antigen from the myocardium with infarction are associated with the intensive immunopathological shifts in the heart.     

Effect of lidocaine and pyromecaine on the size of an experimental myocardial infarct

The experiments on rats with a 3-day myocardial infarction caused by the left coronary artery ligation have shown that multiple lidocaine and pyromecaine injections according to a given scheme decrease the size of the necrosis area. Drug effects were not related to their action on the blood supply of the ischemic area.     

Effect of an opioid peptide on the healing of experimental myocardial infarct

The effect of an opioid hormone (Leu-enkephalin analog Tyr-Dala-Gly-Phe-Leu-Arg) on the healing of myocardial infarction caused by the ligation of the descending branch of the rabbit left coronary artery has been investigated. The peptide was injected intraperitoneally at a dose of 10 micrograms/kg daily. Using light and electron microscopy, the peptide has been shown to exert a pronounced stimulating effect on the healing of the necrotic zone on days 3 and 7 of the experiment. Opioid peptides are suggested to take part in the healing of various disorders.     

Effect of Eleutherococcus on the subcellular structures of the heart in experimental myocardial infarct

The effect of Eleutherococcus on subcellular heart organization in rats with or without myocardial infarction was investigated. It was found that Eleutherococcus decreases ultrastructural lesions in the ischemic area, intensifies regeneration of subcellular structures and accelerates the recovery after myocardial infarction. The accumulation of glycogen, lipids and lysosomes is observed in lipocytes. It is suggested that positive effect of Eleutherococcus during myocardial infarction is related to lipid transformation into glycogen.     

Effect of cordarone on the ultrastructure of cardiac muscle cells in experimental myocardial infarct

The effect of cordarone on the ultrastructure of cardiomyocytes of the periinfarction zone was studied in experiments on 30 cats. Cordarone was injected intramuscularly daily for 3.7 and 15 days in a dose of 10 mg/kg. Experimental myocardial infarction was induced by ligation of the left coronary artery at the border of its medium and inferior thirds. As compared with control, cordarone produced a more demonstrable reduction in the intracellular edema, more rapid recovery of the structure of myofibrils and greater accumulation of glycogen granules by the cytoplasm of cardiomyocytes. At the same time the structure of the mitochondria returned to normal more slowly as compared with control, with persistent widening of the cisternae of the sarcoplasmic reticulum being observed in addition. The changes described indicate that cordarone exerts different actions on the ultrastructure of cardiomyocytes, which is probably based on the drug influence on adrenergic processes and calcium turnover in the myocardium.     

Effect of polypeptides isolated from the heart on the course of experimental myocardial infarct

Polypeptides excreted from the heart have been shown to exert a positive influence on myocardial infarction caused by izadrin injection in experimental rats.     

Effect of adaptation to short-term stress exposure on the fibrillation threshold and ectopic activity of the heart in experimental myocardial infarct

Preliminary adaptation to short-term stress was shown to prevent the decrease in the heart fibrillation threshold and an increase in ectopic activity which is usually observed in experimental myocardial infarction. This protective effect involves an enhanced activity of the antioxidant system. Therefore, a synthetic antioxidant ionol was applied to prevent disturbances of the heart electrical stability in infarction. It was established that ionol completely prevents the decrease in the electrical threshold and the increase in ectopic activity of the heart in experimental infarction. Thus, it can be concluded that ionol possesses an antiarrhythmic effect.     

Ultrastructure of the sinus and atrioventricular nodes in experimental myocardial infarct

The ultrastructure of sinus and atrioventricular nodes was studied in white rats with experimental myocardial infarction. 24 hours after the induction of the disease mitochondrial enlargement characterized by the increase in their area, decrease in the number of cristae and the decline in the rate of mitochondrial energy effectiveness was detected. Different degrees of nuclear chromatin aggregation and membrane permeability for colloidal lanthanum were observed. Characteristic types of conduction cellular lesions were revealed in experimental myocardial infarction.     

The effect of hyperglycemia on the development of experimental myocardial infarct

Experiment on 72 dogs has shown that myocardial infarction (M1) against a background of hyperglycemia proceeds as shifts healing hyperactive MI. Shifts in carbohydrate metabolism results in disturbances of dynamics of the necrotic infarction zone processes that induces complications of healing changes in the content of myoglobin, creatine kinase, aspartateaminotransferase with MI against a background of hyperglycemia greatly differ from those typical of noncomplicated and complicated hyperactive MI.     

Protein-synthesizing function of the liver of rabbits in experimental myocardial infarct

The content of serum albumin in rabbit blood was found to be lowered within the first day after reproduction of experimental myocardial infarction. The rate and the level of translation of endogenous mRNA were studied in cell-free systems from normal rabbit liver and 6-12-24 h after experimental myocardial infarction. The decrease of the total protein synthesis in the crude cell-free system from the liver of experimental animals was shown to depend on the lack of energy supply rather than on the reduced activity of the protein-synthesizing apparatus. The relative drop of protein synthesis in the cell-free system with saturating concentration of ATP, GTP and creatine phosphate is likely to be connected with a decrease in the proportion of membrane-bound polysomes.     

Effect of strophanthin and digoxin on the activity of an experimental epileptogenic focus in the frog hippocampus

It has been shown on frogs with epileptogenic focus induced by the injection of penicillin (1000 U in 0.4 ml) into the hippocamp that preinjection (or injection on the background of the functioning epileptogenic focus) of strophanthin (1.8 and 0.18 microgram/g) or digoxin (1.2 micrograms/g) into spinal lymphaticus sac led to a sharp increase in interparoxysmal epileptiform discharges and electrographic correlates of fits on the ECG. The influence of cardiac glycosides upon the epileptized cerebral neurons is thought to be associated with the capacity of these drugs to inhibit Na+, K+-ATPase of neurons and their axons resulting in the disturbance of cerebral mediator activity.     

Functioning of the monooxygenase system of the liver in experimental myocardial infarct

The experiments on rats have shown that coronary artery ligation reduces the content of microsomal cytochromes P-450 and b5 and causes amidopyrine-N-demethylation and aniline-p-hydroxylation disturbances that persist throughout a 3-week period of myocardial infarction. The investigation of spontaneous lipid peroxidation of microsomal membranes in myocardial infarction has shown that concentration of malonic dialdehyde in microsomal fraction significantly increased by the 7th day after coronary artery ligation, as compared to sham-operated rats.