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Biomedical subjects

V N Shvalev

Publications and source records attributed to V N Shvalev.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Adrenergic innervation of lymph nodes and the thoracic duct].

By means of incubation of slices in 2% solution of glyoxylic acid distribution of adrenergic fibers in the rabbit lymph nodes and in the thoracic lymphatic duct has been studied. Adrenergic fibers get into parenchyma of the lymph nodes via two ways. The first--the perivascular, when the nervous fibers make a plexus and get into the node along the blood vessels, the second--diffuse nervous fibers get together with trabecules in between the lymphoid nodules. The distribution density of the adrenergic fibers is not the same in different groups of the lymph nodes. In the lumbar nodes it is the highest. In the lymph nodes of the cervical part the density of the sympathetic fibers is, as a rule, lower than in the lumbar, but higher than in the axillary nodes. The lowest density of th adrenergic fibers is in the mesenteric, superficial inguinal lymph nodes and in the lymph nodes, situating near the thoracic part of the aorta. In the lymphatic duct wall small amount of adrenergic fibers are revealed, they form a plexus, predominantly in the cranial part.

Adrenergic Fibers↗
PubMed1989

[Staged quality of the transformation of the autonomic nervous system in ontogenesis].

As a result of neurohistochemical and electron microscopic investigations of the autonomic nervous system (ANS) in ontogenesis of the human being and mammalia the premediatory period of its development can be divided into the stage of the nervous crest cells migration into the place of the ganglia anlage and the stage of contact of preganglionic fibers with neural elements. These two stages occur heterochronically. The mediatory period of the ANS development is conditionally divided into five stages. The first is characterized with appearance of mediators in synapses and nervous plexuses in the internal organs. The second--consists in activation of gliocytogenesis and lasts up to 7 months of the human intrauterine life, when the third stage begins--the perinatal maturation of the ANS. In the nervous plexuses myelin fibers appear, perivascular plexuses and structure of the afferent endings become more complex. The fourth stage--completion of the ANS formation--takes place when the child is more than one year of age and it lasts up to sexual maturation. The nervous fibers myelinization is completed, amount of synapses in neurons increases. Then the fifth stage begins--stabilization of the VNS. The postmediatory period takes place not simultaneously in various ganglia of the VNS and has two stages. At first it becomes evident in the sympathetic part of the VNS. Certain morphofunctional manifestations start the stage of the initial exhausion of mediators. In neurons amount of lipofuscin granules grows large, some disturbances in mitochondria and osmiophilic lamellar bodies appear. This stage of the postmediatory period can start early, for example, in the human heart on the fourth decade of life and lasts in the organ up to 60-65 years, when the terminal stage takes place--involutive degeneration of the VNS plexuses.

Animals↗
PubMed1988

[Synaptogenesis in the neural ganglia of the heart in the human embryo].

Electron microscopy was used to study synapse development in the cardiac ganglia of human fetuses ranging from 8 to 27 weeks of ovulation time. Staining with ethanolic phosphotungstic acid was used for analysis of synaptic active zones. Specialization of interneuronal links begins with the appearance of electron dense material on plasmalemmas of nerve cells in the places of simple contacts. First synapses with single synaptic vesicles and short osmiophilic zones were found in cardiac ganglia in 8-week-old fetuses. Large granular vesicles and mitochondria vesicles are formed from cisternae of agranular endoplasmic reticulum in the preterminal parts of axons and moved by axoplasmic transport to the osmiophilic zones of future synapses. Axodendritic synapses appeared earlier in the cardiac ganglia than axosomatic ones, the latter were observed from the middle of gestation. Transient neuroglial synapse-like contacts were found in the cardiac ganglia. Staining with phosphotungstic acid made it possible to distinguish the degree of synapse maturation according to active synaptic zones. The peculiarities of synaptic development in cardiac ganglia in comparison with that in the central nervous system may be accounted for by different origins of the neural tube and of neural crest and by the level of their phylogenic development.

Fetal Heart↗
PubMed1988

[Ultrastructure of the cells of the neural crest].

Ultrastructure of the neural crest cells (NCC) has been studied in 9-day-old white rat embryos. Mechanisms, determining the amount of the NCC that get out of the neuroepithelium of the nervous tube have been discussed. By means of ruthenium red components of the extracellular matrix are demonstrated in the area where the NCC get out and in the ventromedial pathway of migration. Certain peculiarities of ruthenium red fixation by the cells are presented.

Animals↗
PubMed1988

[Adrenergic innervation of the kidneys in man and various laboratory animals].

By means of the neurohistochemical method for slice incubation in 2% solution of glyoxylic acid, innervation of the kidneys of a 57-year-old man after a sudden cardiac death has been investigated, as well as innervation of the kidneys in white rat, rabbit, guinea pig and cat. A rich adrenergic innervation in the organ's blood vessels has been revealed. In particular, adrenergic nervous fibers have been found along the course of afferent glomerular arterioles. Together with innervation of the proximal and distal convoluted tubules, a high density of the terminal adrenergic nervous plexus is revealed along the course of the nephron loops. Adrenergic nervous plexuses of high density are found in the area of the initial part of the urinary excretory pathways and their connection with nervous plexuses of the kidney itself.

Animals↗
PubMed1988

[Adrenergic innervation of various sections of the heart in laboratory animals and man].

By means of incubating slices in 2% glyoxylic acid solution, distribution of adrenergic fibers in the myocardium of various cardiac parts has been studied in the white rat, rabbit, cat, guinea pig and in the man. Both in the animals and in the man the distribution density of the adrenergic fibers of the myocardial plexuses in the auricle is higher than in the ventricle, and in the left half of the heart it is lower than in the right one. There are certain species differences in distribution of the adrenergic fibers. The density of the adrenergic fibers in the guinea pig myocardium is the highest, and in the white rat is is the lowest.

Adrenergic Fibers↗
PubMed1988

[Ultrastructural bases of the development of the neural apparatus of the heart].

By means of electron microscopy developmental dynamics of the human and mammalian innervation has been studied during prenatal period of ontogenesis. Regularities in formation of the intracardiac nervous ganglia and in differentiation of nervous-muscular connections in the myocardium have been stated. Ultrastructural peculiarities of proneuroblasts and the nervous fiber terminals, growing to differentiating cardiomyocytes have been described during the premediator stage of the vegetative nervous system development. Peculiarities of synaptogenesis have been followed, among them those demonstrated as heterochromic formation of pre- and post-synaptic membrane and as uneven accumulation of synaptic vesicles. Development of the nervous-muscular connections have been studied. At the beginning of the mediator stage of the vegetative nervous system development formation of simple contacts between the nervous terminals and cardiomyocytes is intensified, and glial tunics develop rather poorly. Therefore, at the beginning the terminal parts of axons are not surrounded with processes of gliocytes. Simultaneously, formation of small intensively luminescent cells takes place. Development of afferent nervous terminals occurs not only in the myocardium, but in the intracardiac ganglia.

Animals↗
PubMed1987

[Ultrastructure of the epimyocardium and myocardium in early embryos of white rats].

The atrial walls in 10-13-day-old white rat embryos have been studied electron microscopically. The epimyocardium consists of 1-2 rows of cells and has an epitheliomorphic structure. At first the basal membrane is formed on the endocardial surface of cardiomyocytes; intercellular contacts in the lateral parts of the cells possess endo-epicardial polarity. The epicardial layer is formed on the 11th day of the prenatal development, the basal membrane begins to form at the same time on the epicardial surface of cardiomyocytes. Dynamics of differentiation of some cardiomyocytic organelles in cardiomyocytes is described.

Animals↗
PubMed1987

[Ultrastructure of the sympathetic paravertebral ganglia in rat embryogenesis. I. Cytogenesis and cell differentiation].

The development of sympathetic paravertebral ganglia was studied in rat embryos by electron microscopy. The main attention was paid to the initial stages of ganglion formation. The first aggregations of presumptive ganglionic cells were observed in 12 day-old embryos. Single preganglionic terminals appeared in contact with cell bodies sometime later. The appearance of large granular vesicles in the cytoplasm is the first ultrastructural feature of the beginning of neural differentiation of cells. Small granulated cells observed from the 12th day of gestation and neuroblasts differentiate earlier than glial cells. In the ganglia of late fetuses nerve cells varied in the electron density of the cytoplasm, in the degree of distention of rough endoplasmic reticulum and in vacuolization of mitochondria.

Animals↗
PubMed1987

[Ultrastructure of the sympathetic paravertebral ganglia in rat embryogenesis. II. The development of the neuropil and the interneuronal connections].

Electron microscopy was used to study the process of ingrowth of nerve terminals in the primordia of sympathetic ganglia and the formation of specialized contacts. Nerve terminals appeared first in 12 day old embryos. In the forming ganglia of 13 day old embryos there are many preganglionic nerve terminals and processes of principal neuroblasts. The growth cones of nerve endings are usually distended and with transparent cytoplasm. The plasmalemmas of growth cones are lacking often the trilaminar structure. Synapses were observed first in 16 day old fetuses. They are axo-dendritic and axo-somatic ones. The number of synaptic contacts does not increase much during prenatal period. Presumptive afferent nerve terminals were found in the late fetuses.

Animals↗
PubMed1987

[Ultrastructural study of the myocardial cells of the human sinus node in sudden coronary death].

Light- and electron-microscopic studies were performed on hearts from 23 males (aged 34 to 69 years) who had died suddenly with coronary heart disease. The hearts from 6 males of the same age group who had succumbed to extracardiac causes (including injuries) served as controls. Chronic abnormalities and acute destructive changes in the sinus node were observed in 82.6% and 87% of the cases, respectively. Various types of destructive changes seen in specialized conducting myocytes of the sinus node are described. Lesions in the microcirculatory bed, neural elements, and the connective-tissue component of the nodal myocardium were detected. Contributions of the detected changes to cardiac arrhythmia and sudden coronary death are discussed.

Adult↗
PubMed1986

Changes in neural and humoral mechanisms of the heart in sudden death due to myocardial abnormalities.

Quantitative neurohistochemical study of adrenergic elements of the myocardium and the adrenal medulla in victims of sudden death revealed an unequal and focal depletion of catecholamines attributable to prior pathologic processes in the myocardium. The greatest changes in cardiac innervation were found in cases of acute myocardial infarction and alcoholic cardiomyopathy, and the adrenergic plexuses were better preserved in cases of coronary heart disease without focal myocardial changes. Ultrastructural study of cardiac innervation in patients who died suddenly showed more pronounced changes in the nerve plexuses of the sinus node than in the perinodal nerves of the working myocardium. The changes in coronary artery innervation were usually related to the severity of stenosis due to fibrous plaque; desympathization of the vessels and the adjoining myocardial zone was also found in cases with 50% or greater occlusion of the lumen. The bulk of chromaffinocytes were depleted and weakly luminescent in the adrenal glands of patients with acute myocardial infarction who died suddenly. In contrast, chromaffinocytes with moderate and bright luminescence were prevalent in cases of sudden death with scarring from previous myocardial infarction and with alcoholic cardiomyopathy. Ultrastructural and histochemical examinations demonstrated that changes in the neurons of sympathetic ganglia increased with more severe atherosclerotic lesions of the aorta and with greater changes in the vessels supplying the ganglia. In experiments on rabbits and dogs, both coronary artery ligation and electrostimulation produced cardiac fibrillation followed by a local increase in luminescence intensity of the myocardial nerve plexuses when their density remained high. Chemoreceptors located along the coronary vessels and pulmonary artery in dogs included small cells with bright fluorescence and adrenergic nerve fibers.

Adrenal Glands↗
PubMed1986

[Tissue composition of the sinoauricular area of the human heart (a quantitative electron microscopic analysis)].

An original technique for fixation, treatment and oriented embedding of the sinoauricular area material of the human heart makes it possible to study ultrastructure of the conducting myocardial in the sinus node (SN) and that of the parasinusoid working myocardium in the right atrium (RA), while the spatial interrelations, between the structures of the area examined are fully kept intact. Quantitative analysis of the SN and RA myocardial tissue composition has been performed. Contents of muscular, connective tissue, vascular and nervous components in the SN and RA have been estimated in hearth of 8 men died from causes not connected with any heart disease. Informativity degree of each component studied is discussed for differentiating the SN conducting myocardium from the RA working myocardium in ultrastructural investigations of the human heart in autopsies.

Adult↗