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Biomedical subjects

S Nikolov

Publications and source records attributed to S Nikolov.

At least 55 records · Page 3Linked to original sources
PubMed1984

[Tubular structural pattern of filaments of elastic fibers].

Substructural organization and morphogenesis of elastic fiber filaments (EFF) from different organs (blood vessels, auricular cartilage, skin) are described. EFF reveal a tubular pattern of organization. In cross section, the filament's "wall" is build up of 4 dense particles (subunits), which surround an electron-lucent interior; in longitudinal section, subunits seems to be arranged in a chain-like manner. The EFF's tubular organization is somehow similar to that of intermediate filaments and cytoplasmic microtubules. An universal structural pattern for both, intra- and extracellular filamentous structures, with skeletal function is suggested.

Animals↗
PubMed1981

[Matrix vesicles in various "elastic" organs].

Matrix vesicles (MV) have been found during normal development in the rabbit and rat aorta and pulmonary trunk as well as in the elastic cartilage of the rat external ear. In spite of the morphological variability of MV, two basic types can be ruled out: MV with dense osmiophilic content, and light or electron-translucent MV. MV of the first type are considered to be extracellular lysosomes. MV in the vessel wall are predominantly localized in the subendothelium, and the border-zones between media and endothelium or media and adventitia; in elastic cartilage they are localized near the perichondrium. Especially often they can be seen at the place of contact between elastic and other fibers of the intercellular space. They can even penetrate the elastic membranes and plates. The parts of the organs mentioned encounter higher functional demands and are more active during development and growth. The MV appear almost exclusively a short time before birth, and predominantly during the first 20-60 days of postnatal life. Their origin may be due to exocytosis and the detachment of parts (Mikroapokrinie) of endothelial cells, smooth muscle cells, fibrocytes and chondrocytes. The MV are considered to be a substrate for subsidiary extracellular mechanisms of adaptation during the normal ontogenesis of the elastic tissue of these organs.

Animals↗
PubMed1980

[Drug cardiopathies].

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Antidepressive Agents, Tricyclic↗
PubMed1980

[Ultrastructural aspects of the transendothelial passage of macromolecules in the pulmonary trunk of the rat].

The authors examined the transendothelial passage of tracer macromolecules (feritin) in the endothelial cells of the lung stem of white rats (Wistar) by means of an electron microscope. They found that the feritin granules were detained by the pilous surface of the luminal cytolema at the initial phase of the process. This was enhanced also by luminal buds and invaginations respectively paraluminal canals, functioning as stagnating devices. The uptake and transcellular passage of the macromolecules was realized by micropinocytose vesicules, part of which were intracellularly and formed vacuole depots. Vesicules were formed from them secondarily, carrying the tracer mainly basaly. The authors observed also a bead roll pattern of transport vesicyles, which, passing tracer molecules one to another, formed functional trancellular canals for quick transport. There were certain dependences between the established forms of trancellular passage and the circulation time of feritin.

Animals↗
PubMed1979

[Heart rupture as an outcome of myocardial infarct].

The authors studied the incidence and character of cardiac rupture in 109 deceased of myocardial infarction. Rupture was encountered in 21.1 per cent. Out of the 23 ruptures -- 21 were external and 2 -- internal at the intraventricular septum. Cardiac rupture is an occurence mainly in subjects over 60. Extensive transmural infarction was diagnosed in all cases of external rupture. The diagnosis was made while still alive in a little more than a half of the cases. In seven of the cases, the external rupture was with a protracted progress with the following clinical manifestations -- preceeding strong, refractory, continuous pain and anxiety, protracted shock state, prolonged pericardial friction. Characteristic ECG changes are described in case of protracted ruptures enabling the admittance of the rupture while still living. The authors express the opinion that in cases with protracted rupture, surgical life-saving intervention is possible.

Adult↗
PubMed1978

[Pulmonary changes in myocardial infarct].

The authors examined 90 patients with myocardial infarction with a view to the lung changes developed and especially to the manifestations of pulmonary stasis. Series of face roentgenographies of the lungs were made of the patients in lying down position. In 76,7 per cent of the patients X-ray findings of pulmonary stasis were found. The dilated veins in the upper lung lobes are the earliest and most frequent manifestations, suggesting congestion. They are found in 23,3 per cent of the cases. Most important, among the X-ray findings, according to the authors, are those of perivascular edema--hilus images with widened and indistinct lines (24,4%). The X-ray findings of lung congestion and interstitial edema are early symptoms of pulmonary edema, in case the physical data from the lung examinations are negative. The therapeutic measures, at that stage, could prevent the development of a severe and very often fatal edema of the lungs.

Adult↗
PubMed1977

Fine morphological aspects of the secretory process in arterial smooth muscle cells. II. Role of microtubules.

Preliminary results are presented regarding the role of the microtubular system in the secretory process in the rabbit aorta and pulmonary trunk smooth muscle cells. The results are based on electron microscopic findings of the effect of colchicine in vivo. On colchicine treatment an accumulation of secretory granules versus a vacuolar type of dilatation of the rough endoplasmic reticulum cisternae distinguishes two groups of smooth muscle cells. It is suggested that two secretory pathways operate in these cells, and that the cell microtubular status plays a key role in triggering one or the other pathway.

Animals↗
PubMed1976

Quantitative determination of ruscogenin in Ruscus species by densitometric thin-layer chromatography.

A densitometric t.l.c. method of quantitative determination of ruscogenin was elaborated. After separation with the aid of t.l.c., the colourless ruscogenin spots were located with the aid of a p-dimethyl-aminobenzaldehyde solution and were submitted to densitometry. It was found that under the selected conditions a linear dependence exists between the betaI% value and lgC within the range of 0.5--10 mug ruscogenin. The determination of ruscogenin is done in the presence of the remaining components of the sample. The method is free of any systematic error. The method was applied in the determination of the ruscogenin content of the above-ground and underground part of Ruscus aculeatus and R. hypoglossum, extracts of the same plants, and capsules with further to the R. aculeatus extract also contained bioflavonoids. It was found that the content of ruscogenin in the underground and the above-ground parts of R. hypoglossum is 0.14 and 0.10%, respectively, while for R. aculeatus the respective values are 0.12 and 0.08%. The extract contains 1.6% ruscogenin, and the capsules 0.09 mg each.

Capsules↗