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Biomedical subjects

O M Pozdniakov

Publications and source records attributed to O M Pozdniakov.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Cardioprotective effect of combined use of coenzyme Q9 and cyclohexyladenosine in ischemia, reperfusion and acute myocardial infarction].

Effects of coenzyme Q9 (25 mg/kg), N6-cyclohexyl adenosine (CHA, 100 micrograms/kg) and their combination were compared in rats with short-term or permanent ligation of the left coronary artery. The following parameters were evaluated in three series of experiments: 1) incidence and duration of ventricular fibrillation and tachycardia during coronary occlusion (10 min) and consecutive reperfusion (5 min); 2) contractility and electrical stability of the heart (ventricular fibrillation threshold) in animals with 2-day myocardial infarction; 3) ischemic myocardial mass after coronary occlusion (5 min) and necrotic tissue mass in 2-day myocardial infarction. The rats were given oral drugs 5 days and 2 hours before the study. All the experiments were performed in open-chest anesthetized (nembutal, 50 mg/kg) rats exposed to ventilation at room air. Both the coenzyme Q9 and CHA significantly reduced the incidence and duration of coronary occlusion and reperfusion arrhythmias, prevented cardiac contractile depression (heart rate.developed pressure) and increased ventricular fibrillation threshold). The effect of coenzyme Q9 was more marked than that of CHA. Coenzyme Q9 substantially reduced necrotic tissue mass while CHA diminished ischemic tissue mass. At the same time the total cardioprotective action of the Q9 + CHA combination was more pronounced than that of them used alone.

Adenosine↗
PubMed1990

[The effect of a 3-hydroxypyridine-class antioxidant on disorders of the microcirculatory system in experimental dyslipoproteinemia and its alimentary correction].

The effect of antioxidant (AO) of the 3-hydroxypyridin class on microcirculatory system (MC) disorders of rabbits with dyslipoproteinemia (DLP) and its alimentary correction (the standard ration--9 months) was studied. Aorta, the intestinal mesentery microcirculatory bed, the microvessels adrenergic innervation, erythrocyte morphology were examined. The various lipoprotein fractions and lipid peroxidation (LP) products were studied in venous blood. After AO including into atherogenic diet (ATD) the lipid homeostasis disorders, the LP activation, MC disturbances, anomalous erythrocyte form appearance and atherosclerosis changes in aorta were less pronounced. Under the AO influence when DLP was corrected the initial level of lipid metabolism and LP restored, the MC disorders and the atherosclerosis changes in aorta regressed in a shorter period of time. The interrelation was observed between the DLP level, the structural and functional MC disorders and the extent of aorta atherosclerosis. Thus, DLP and LP correction at the early stages of pathological process can lead to the disappearance of MC disorders, what seems important for the prevention of atherosclerosis. The role of the LP activation in MC disorders in DLP and mexidol effect on them, especially in complex with DLP correction were evaluated.

Animals↗
PubMed1988

[Morphometry of the vesicular apparatus of the neuromuscular junction with different modes of transmitter release].

Neuromuscular junctions in the diaphragm muscle of rats were studied, using a usual chemical fixation technique and quick prefreezing of the muscle. The number of synaptic vesicles in the vicinity of presynaptic membrane decreased significantly during synaptic function activation. Quantitative investigation of axon terminal vesicle apparatus revealed heterogeneity in the size of synaptic vesicle pool. The pattern of synaptic vesicle size distribution in different functional states of the synapse suggests that size heterogeneity reflects their functional peculiarities.

Animals↗
PubMed1988

[Changes in the ultrastructure of neuromuscular synapses in rats under the effects of space flight factors].

The influence of a 7-day space flight on board the biosputnik "Kosmos-1669" on the neuro-muscular synapses (NMS) of soleus, gastrocnemius and diaphragm muscles distinct in their functions has been studied. The synapse restructuring on the basis of destructive- regenerative process has been discovered. It is manifested to a great extent in the soleus muscle, to a lesser extent in the gastrocnemius muscle and the least of all in the diaphragm muscle. The changes observed in synapses may be caused by the attenuation of their function in weightlessness.

Animals↗
PubMed1988

[Characteristics of post-traumatic differentiation of satellite cells in skeletal muscles].

Muscle trauma during preliminary denervation stimulates generation and differentiation of satellite cells. There are two types of posttraumatic cells with different types of albumin synthesis (intracellular and extracellular) under the sarcolemma of the muscle fibers. It is assumed that either two different types of cells differentiating along myogenic and fibrogenic lines are to be found under muscle sarcolemma, or the original satellite cell is capable of differentiating in several directions.

Albumins↗
PubMed1988

[Neuromuscular junctions of the rat diaphragm in experimental hypoparathyroidism].

The ultrastructure of neuro-muscular junctions in diaphragm muscle underwent certain changes in the course of experimental hypothyrosis (thermal destruction of a part of parathyroid gland). The most pronounced structural changes were observed in maximum hypocalcemia (7 days after the operation). There was a correlation between the pattern of a transmitter release and some parameters of vesicular apparatus (the number and volume distribution of synaptic vesicles). These effects suggest that hypoparathyroidism causes an increase in calcium content in axon terminals.

Animals↗
PubMed1986

[Satellite cells in movement disorders of various etiologies].

The ultrastructural analysis of the muscle biopsy samples from patients with different neuro-muscular diseases revealed; both degeneration and regeneration of the muscle fibres. The number of satellite cells was increased due to their division and myonuclear segregation. Activated satellite cells were converted into myoblasts which probably could replace the injured fragments of the muscle fibres or form the myotubes. The process of muscle fibre regeneration is restricted not only by the damage of the muscle itself, but by the dystrophic process affecting satellite cells.

Cell Differentiation↗
PubMed1985

[Inherent morphofunctional effects of experimental procedures in studying the mechanism of transmitter release].

Muscle detubulation with the aid of glycerin is widely used in studying synaptic transmission in the neuromuscular junction. In view of this fact, it was decided to examine its effects on structural and functional parameters of the neuromuscular junction of rat diaphragmal muscle. It was shown that the structure of the junction was on the whole preserved, although during glycerin treatment and for a certain period after glycerin washing off, some alterations were recorded (an increase in the volume of vesicles, a change in volume distribution of vesicles, and so forth). The interrelationship between axonal terminal and Schwann cells was altered. Addition of glycerin was found to provoke a transitory activation of the transmitter release, but later on no changes were seen.

Animals↗
PubMed1985

[Structural changes in the pulmonary vessels and parenchyma in experimental hypercholesterolemia and atherosclerosis].

Light and electron microscopy were employed to study the microcirculatory bed (MCB), intraorganic vessels and lung tissue in rabbits in the first hours (1, 3, 6, 15, 24 and 48 h) after a single administration of cholesterol (ChS) and in the course of the development of experimental atherosclerosis. The MCB demonstrated changes such as dilatation of the venular part, arteriolar constriction, red cell aggregation in capillaries and venules, and stases. At the early stages of experimental atherosclerosis induced by the diet the permeability of the air-blood barrier and the synthesis of lung surfactant were found to be deranged. Vessel-tissue changes in the lungs progressed with an increase in the length of the diet (1-8 months) and were alike the picture seen in chronic nonspecific lung diseases, particularly in what is called senile emphysema. A relationship was established between the degree of changes in the MCB and HCh gravity. Atherosclerotic lesions in the intraorganic arteries occur and progress parallel with the development of this process in the intramural arteries of the myocardium. The data obtained attest to an important role of lipid metabolism disorders in the development of lung pathology and may have a certain significance in specifying the pathogenesis of chronic nonspecific lung diseases, especially.

Animals↗
PubMed1983

[Ultrastructural study of posttraumatic regeneration of muscle tissue in adult rats].

Regeneration of muscle fibers in pubertal rats (days 8 and 10 after mechanical trauma) can be followed until the occurrence of muscle tubules, resembling tissue formation during embryogenesis. Apart from the cellular type regeneration, the contractile apparatus recovery was also observed inside the preserved basal-sarcolemmal skirts according to the type of intracellular reparative regeneration.

Animals↗
PubMed1981

[Changes in the ratio of quantum-vesicular parameters in the presence of disrupted synaptic transmitter secretion in the neuromuscular junctions of mammals].

To test the vesicular hypothesis of quantum release, some parameters of synaptic vesicles (SV) and miniature end plate potentials (MEPPs) were compared in phrenic neuromuscular junctions of rats poisoned with tetanus toxin (TT). The poisoning with TT that suppresses the transmitter release led to marked changes in the distribution of MEPPs amplitudes and SV diameters as compared to normal, namely to the transformation of unimodal histograms for both parameters to polymodal ones. The transformation was accompanied by a significant increase in variation coefficients of both distributions, thus indicating the disturbances of vesicle-quantum formation. The total number of SV in the poisoned terminal increased by 59% which might reflect both the lifetime situation characteristic for normal and/or real accumulation of the transmitter quanta as a result of the TT-hampered exocytosis through the presynaptic membrane, since during the reactivating action of ouabain, the transmitter release level from the poisoned terminal exceeded that for normal to about the same measure. The results obtained may be regarded as providing evidence in favour of the vesicular hypothesis.

Animals↗
PubMed1981

[Ultrastructure of the wall of the femoral artery in rats with chronic regional arterial hypotension].

In experiments on rats a lowering of the arterial pressure in the vessels of the body posterior was attained by occlusion of the aorta distally to the ostia of renal arteries. Twelve days after the operation there occurred a significant thinning out of the muscle layer and intermuscular septa in the wall of the femoral artery. Also, there was a disappearance of extracellular matrix vesicles usually seen in great numbers in tunica media of the artery. The animals with arterial hypotension of one- and three-month standing manifested a negligible number of extracellular vesicles; the thickness of the muscle layers and intermuscular septa increased but remained far less than normal.

Animals↗
PubMed1981

[Ultrastructural study of the early stages of skeletal muscle regeneration in sexually mature animals].

It has been found that during the crush of musculus gastrocnemius in adult rats, there occur two sources of myoblast formation: satellite cells and nucleo-sarcoplasmatic areas that split off injured muscle fibers. The latter process is preceded by changes in the ultrastructure of the perinuclear cytoplasmic zone where microtubules, ribosomes and polyribosomes, fissural cavities, vesicles, myofilaments, and cisterns of the rough endoplasmic reticulum are formed.

Animals↗