Biomedical subjects

O M Pozdniakov

Publications and source records attributed to O M Pozdniakov.

At least 55 records · Page 3Linked to original sources

PubMed1981

[Neurohistochemical and ultrastructural study of the adrenergic innervation of the wall of the rat posterior vena cava during chronic venous hypertension caused by experimental oleothorax].

Chronic venous hypertension in rats was provoked by injection of polymethyloxane into the pleural cavity. Hypertrophy of muscular tissue was accompanied by reconstitution of adrenergic nervous structures. In the early stages (up to 40 days), the changes in the latter are reactive in nature: first there occurs a weakening of luminescence, rare-fraction of the network and then "hyperneuria". Pulmonary heart formation was followed by marked hypertrophy of SMC, increased density of adrenergic fibers, convergence of SMC and nerve terminals (synapse formation).

Adrenergic Fibers↗

PubMed1981

[Structural changes in the microcirculatory bed and perivascular connective tissue in the myocardium during experimental hypercholesterolemia].

Light and electron microscopy were used in rabbits to study the effect of hypercholesterolemia (HC) on the microcirculatory bed (MCB), perivascular connective tissue and specialized cells of the myocardium. Within the first hours (1, 3, 6, 15, 24, 48 h) after cholesterol single administration to the animals, there were structural changes in the MCB, aggregation and superficial changes in red blood cells (echinocytes), stases, the presence of unusual ultrastructures in elastic membranes (EM) of the arterioles, in the amorphous substance of perivascular connective tissue, specifically near the venules, and focal dystrophy in cardiomyocytes. The ultrastructures detected in the EM of the arterioles and perivascular tissue seem likely to be the complexes of atherogenous lipoproteins and glycosaminoglycans. The transfer of the animals on the atherogenous diet entailed the reconstruction of small arteries of the myocardium and formation in them of so-called "Conti's pillows" as well as lipid deposition. A complex of structural changes revealed in the myocardium in the early stages of HC indicates the increased permeability of the microvessels, alterations in the blood rheological properties and circulatory disorders. A relationship was found between the intensity of the changes cited and blood cholesterol level. Injury to the MCB of an organ is likely to play an initial part in the mechanisms of atherogenesis.

Animals↗

PubMed1980

[Ultrastructural and functional changes in the synaptosomes of the rat brain on in vitro electrostimulation].

Electrostimulation of suspension of the rat brain synaptosomes causes Ca(2)+-dependent endogenous norepinephrine release and at the same time Ca(2)-dependent increase of the mediator content in the synaptosomes. The activity of cAMP declines under the same conditions. Electrostimulation does not alter the ultrastructure of the synaptosomes but raises the content of high electron density synaptosomes.

Animals↗

PubMed1980

[Ultrastructural changes in the wall of the inferior vena cava following acute obstruction of venous drainage].

Ultrastructure of the abdominal part of rat vena cava posterior was studied over a period of 2 to 20 hours after acute failure of blood outflow. This disturbance was induced by vein coarctation with a silk ligature. During the first two hours and afterwards, alteration and desquamation of the endothelium were observed. 16--20 hours after vein coarctation there occurred degeneration of some smooth muscle cells and transitory migration of blood monocytes to the vein wall. Platelet aggregations could be seen rarely. Intimal fibromuscular thickenings reported in previous papers were located at the most severely affected sites of the endothelium. The data obtained confirm the hypothesis of the presence of endothelial muscle interactions.

Animals↗

PubMed1980

[Structural organization of the wall of the inferior vena cava in rats].

Structural organization of the wall in the posterior vena cava has been studied with light optic (neurohistological and neurohictochemical techniques including) and electron microscopical methods in mature and 1-month-old rats. According to its structure, the vascular wall in question can be divided into 3 parts. Two of them are situated in the thoracic cavity, the first occupying a half of the thoracic part of the vein, is surrounded with cardiomyocytes, and in the second part the wall consists of endotheliocytes, fibroblasts, collagenous and elastic fibres. The third part of the vein is situated in the abdominal cavity; together with endotheliocytes, internal elastic membranes and collagenous fibres there is a great number of adrenergic neural fibres, a well developed middle membrane is presented by smooth muscle tissue; there is also a layer of "veil-like" fibroblasts. All the elements of the wall are connected with each other and function as a single whole. Endothelial-muscular, muscular-muscular and neuro-muscular connections seem to be of a special functional importance. Structural differences in the venous parts mentioned above appear to be connected with their functional pecularities. Structural differentiation in the young rat venous wall and myocytes coinsides with the differentiation of adrenergic nerve structures.

Animals↗

PubMed1976

[The vesicular system of the endothelium in the blood-carrying capillaries of the diaphragm with different functional states].

Micropinocytotic vesicles were counted in the endothelial cells of blood capillaries in the muscle of the diaphragm in its indirect rhythmic stimulation at a frequency of 50 imp/s after section of the phrenic nerve, and also in natural contraction and relaxation of the muscle during respiration. A change in the total count of the vesicles and even more pronounced changes in the ratio of the vesicles bound with plasmic membranes and freely located in the cytoplasm of the cells were revealed; this pointed to the change in the transendothelial transfer of substances. It appeared that the state of the process of vesicle formation could influence the method of fixation applied.

Animals↗

PubMed1976

[Neuro-muscular synapse ultrastructure in the Lambert-Eaton myasthenic syndrome].

A study was made of the ultrastructure of the neuro-muscular synapses in the patients with the myasthenic Lambert-Eaton syndrome. Most of the synapses displayed an increased content of synaptic vesicles in the axon terminals, and the anastomosing synaptic folds were increased in number and depth. Local destructive changes were found in the terminals of some synapses. The data obtained confirmed the fact that this syndrome was underlied by disorder of the transmitter release from the presynaptic structures.

Bronchial Neoplasms↗

PubMed1974