Characterization of cardiac function in hypertensive rats of the NISAG strain (an ECG study)

Analysis of ECGs recorded in 3 standard leads, 3 augmented limb leads, and 3 chest leads revealed typical signs of left ventricular hypertrophy with a relative deterioration of coronary blood supply in NISAG rats, a new strain with hereditary arterial hypertension. These signs are considered to be characteristic of an established arterial hypertension and may be taken as evidence that the NISAG strain can serve as an adequate animal model of human hypertensive disease. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 7 pp. 17–18, July, 1994 Presented by V. A. Trufakin, Member of the Russian Academy of Medical Sciences     

Alterations in cardiac function in response to epinephrine in rats with hereditary hypertension (An ECG study)

A comparative electrocardiographic evaluation of changes in cardiac function in rats with hereditary arterial hypertension (NISAG strain) and normotensive (Wistar) rats in response to a single epinephrine injection revealed much more pronounced changes in NISAG rats, including an unfavorable time course of electrocardiographic waves (left ventricle overload) and impaired conduction (blockade) and excitability (extrasystoles). The results indicate that the myocardium of NISAG rats is much more responsive to the acute stimulation of adrenergic receptors by epinephrine than is the myocardium of normotensive rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 10, pp. 372–375, October, 1995 Presented by V. A. Trufakin, Member of the Russian Academy of Medical Sciences     

Effects of arginine vasopressin on different cardiac arrhythmias

It was shown that arginine vasopressin positively affects the course of cardiac arrhythmias caused by aconitine, atropine, glypine, amphetamine, and ketamine, but not by calcium chloride. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 3, pp. 272–274, March, 1999     

Effect of exogenous ATP on cardiac activity in rats

In vivo effects of exogenous ATP on cardiac activity were studied on adult rats. Intravenous administration of ATP produced a positive chronotropic effect, but did not affect the stroke volume. This was due to activation of type II purine receptors, rather than due to the influence of ATP hydrolysis products, since P1 receptor agonist adenosine was inefective. The blockade of β-adrenoceptors and muscarinic receptors did not modify the positive chronotropic effect of ATP, which indicated that this action was not realized via sympathetic or parasympathetic nerves. ATP applied against the background of atropine blocade produced a 4-fold increase in the variability of heart rate typical of activation of the parasympathetic myocardial regulation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 4, pp. 377–380, April, 2000     

Effect of atp and cocarboxylase on activity of malate dehydrogenase and its isozymes in blood serum and myocardium

Changes in the activity of malate dehydrogenase (MD) and its isozymes in the blood serum and heart muscle of rats were investigated during hypoxia and under the influence of ATP and cocarboxylase. An additional cathodic isozyme (MD₄) appeared in the blood serum during hypoxia. Under the influence of ATP and cocarboxylase the metabolic changes in the blood and myocardium induced by hypoxia did not correlate fully.Presented by Academician of the Academy of Medical Sciences of the USSR A. A. Vishnevskii.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 80, No. 8, pp. 48–50, August, 1975.     

Effect of hyperbaric oxygenation on some functional and morphological properties of the heart and on catecholamine metabolism in compensatory hypertrophy of the myocardium

Less-marked hypertrophy and signs of myocardial degeneration developed in rabbits exposed for one month to hyperbaric oxygenation (HBO) after the formation of stenosis of the ascending aorta, and the contractile power of the left ventricle was increased more than in animals with stenosis of the aorta kept under ordinary conditions. In rabbits with hypertrophy of the heart developing under conditions of HBO increased powers of adaptation of the myocardium to physical exertion were accompanied by an increase in the functional reserve of the sympathetic control apparatus. HBO evidently favors the development of optimal adaptation of the heart to an increased pressure load.Department of Hyperbaric Oxygenation, All-Union Scientific-Research Institute of Clinical and Experimental Surgery, Moscow. (Presented by Academician B. V. Petrovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 7, pp. 19–22, July, 1977.     

Effect of chronic stimulation of negative and positive emotiogenic hypothalamic centers on production of cardiac arrhythmias

Changes in cardiac activity arising during prolonged (up to 1 or 2 weeks) electrical stimulation of the ventromedial hypothalamic nuclei were investigated in chronic experiments on 46 rabbits. Disturbances of the cardiac rhythm, in the form of tachycardia, atrial flutter and fibrillation, ventricular extrasystoles, and paroxysmal ventricular techysystole developed mainly during the first days of stimulation and were stopped by administration of Inderal. In animals subjected to stimulation of the ventromedial nuclei for 1–2 weeks, functional weakness of the cardiac pacemakers was found, as shown by an increase in poststimulation depression of automatic activity of the pacemakers and the appearance of Luciani's periods. Disturbances of the cardiac rhythm arising in response to stimulation of the ventromedial nuclei are abolished by stimulation of the lateral hypothalamic area.Laboratory of Experimental Cardiology, P. K. Anokhin Institute of Normal Physiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 11, pp. 1288–1291, November, 1976.     

Effects of ultrasound,the polyene antibiotic amphotericin B,and their combination on biomembranes of yeastlikeCandida fungi

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 10, pp. 391–393, October, 1993     

Polyploidy in the myocardium and compensatory reserve of the heart

The mammalian heart is a polyploid organ. Cardiac myocytes undergo polyploidization in the early postnatal ontogeny, and the degree of their polyploid depends on the conditions of heart growth. The myocardium of healthy persons is characterized by considerable individual variability of polyploidy. The principal mechanism by which normal and compensatory growth of the heart occurs in adult mammals is through increases of cytoplasmic mass in postmitotic myocytes. In the normal myocardium, the protein mass of myocytes does not correspond to the gene dosage, while their protein mass in a hypertrophic myocardium becomes a multiple of their ploidy. The capacity of polyploid myocytes to grow so as to double their mass constitutes the reserve of cardiac growth. This reserve, which is laid down in the early ontogeny, materializes in response to functional overloading of the heart in adult life. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 5, pp. 454–459, May, 1995 Presented by D. S. Sarkisov, Member of the Russian Academy of Medical Sciences     

Assessing the safety of focused ultrasound for noninvasive exposure of the heart

Measurements of temperature and macroscopic and microscopic studies show a relatively normal status of the presenting tissue at the site of focused ultrasonic beam during noninvasive exposure of the heart through the thoracic wall in dogs: the temperature in the subcutaneous fat of the thoracic wall partially submerged in water is no higher than 38°C and 40.5°C in the periosteum. Warming of the periosteum during treatment by noninvasive methods may be the limiting factor at sites where the bones are located close to the surface, for example, the ribs. Skin burns may be prevented by focused ultrasonic exposure through aqueous medium. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 3, pp. 332–335, March, 1997     

Effect of native venom of red cobra (Naja pallida) on morphological and rheological properties of erythrocytes

The effect of native venom of red (spitting) cobra (Naja pallida) on human erythrocytes is studied using the methods of electron microscopy and filtration through Millipore filters. Morphological analysis reveals marked transformation of discoid erythrocytes to echinocytes. More prolonged contact of the blood with the venom impairs the deformability of erythrocytes and induces hemolysis and the sludge syndrome. The results indicate a potent cytotoxic effect of native venom of red cobra. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 10, pp. 425–427, October, 1995 Presented by V. S. Savel'ev, Member of the Russian Academy of Medical Sciences     

Interstitial microfibrils in the myocardium of patients with rheumatic and congenital cardiac defects

Electron-microscopic investigation of biopsy specimens of heart tissue from patients with rheumatic and congenital cardiac defects revealed aperiodic microfibrils, the number of which was proportional to the fibrosis of the myocardium, on the basal membranes of the capillaries and muscle fibers and also in the lumen of the T-tubules and their vacuolar expansions. If signs of rheumatic carditis are present the myofibrils are less regular and their number somewhat greater. Microfibrils are rutheniophilic and argyrophilic and consist of elementary fibrils of reticular fibers. Their hyperplasia is the ultrastructural equivalent of the reticular skeleton of the hypertrophied myocardium in patients with cardiac defects.Institute of Rheumatism, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. I. Strukov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 1011–1014, August, 1976.     

Adaptation to hypoxia,unlike adaptation to stress,fails to protect the isolated heart from reperfusion after total ischemia (An NMR study)

Effects of adaptation to hypoxia on the contractility of isolated rat hearts and on their levels of ATP and inorganic phosphate after total ischemia were evaluated. This adaptation failed to render the cardiac energy-supplying system more resistant to postischemic reperfusion and thus did not accelerate the restoration of cardiac contractility after ischemia. The results of adaptation to hypoxia were then compared with those of adaptation to stress, which had been shown to bring about a marked increase in cardiac resistance to postischemic reperfusion. It is concluded that the profound differences noted between the cardioprotective effects of these two forms of adaptation are due to a much greater accumulation of stabilizing proteins from the HSP70 family during adaptation to stress. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 11, pp. 481–484, November, 1995 Presented by N. R. Paleev, Member of the Russian Academy of Medical Sciences     

Resistance of the myocardium to adrenalin in rats adapted to hypoxia

The intensity of the changes produced by adrenalin in the myocardium of rats adapted to hypoxia was studied after its administration to the intact animal and perfusion of the isolated heart. The changes were revealed by histochemical reactions for succinate dehydrogenase activity and staining for lipids. After intramuscular injection of a cardiotoxic dose of adrenalin (2.0 mg/kg) into adapted rats no damage to the myocardium was found, whereas perfusion of the isolated heart with adrenalin (20 g/ml) caused the formation of micronecroses of the cardiocytes. However, their volume was statistically significantly smaller than in the isolated heart of intact rats under similar conditions. Differences in the sensitivity of the myocardium in vivo and in vitro indicate that the phenomenon of protection of the myocardium against the harmful effects of adrenalin in rats adapted to hypoxia is manifested at the level of the intact organism. The increase in the resistance of the myocardium itself is probably due to an increase in the power of the metabolic systems during adaptation.Department of Pathological Physiology, Patrice Lumumba Peoples' Friendship University. Department of Geographic Pathology, Research Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 9, pp. 265–268, September, 1977.     

Effect of biotechnological cytochromec on the early postocclusion and reperfusion arrhythmias

Biotechnological cytochromec showed a lower antiarrhythmic activity in cats with acute occlusion and reperfusion arrhythmias than trimecaine, verapamil, and quaternidine but a higher activity than anapriline. Under experimental conditions, cytochromec potentiated the antiarrhythmic effect of trimecaine and quaternidine. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 1, pp. 89–91, January, 1999     

Functional and morphological interventricular relationships during chronic overload of the primarily intact left heart in a model of experimental vasorenal hypertension

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol.116, N ^o 11, pp. 462–464, November, 1993     

Effect of digoxin on acid hydrolase activity in the myocardium

Dose-dependent effect of digoxin on cardiac lysosomal enzymes is demonstrated. In doses of 2.5 and 5 mg/kg digoxin suppresses and in a dose of 10 mg/kg increases the activity of myocardial acid hydrolases. By sensitivity to digoxin, the enzymes rank as follows: β-glucosidase>β-galactosidase>acid phosphatase. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 1, pp. 51–55, January, 1998