Biomedical subjects

A K Kranchev

Publications and source records attributed to A K Kranchev.

14 recordsLinked to original sources

PubMed1988

[Some problems of the morphogenesis of bullous emphysema of the lungs].

The analysis of 93 cases of bullous pulmonary emphysema provided evidence for the significance of valvular mechanism of bulla formation operable at two levels: in small bronchi and bronchioles on the one hand and in the area of subpleural fibrosis on the other hand, the latter arising in the result of subpleural atelectasis or subpleural carnificating pneumonia. Relevant pathology is characterized by peripheral acinus situated tangentially to the pleural surface. Electron-microscopic examination revealed pneumocytes of the second type on the internal bulla surface.

Adult↗

PubMed1988

[Changes in the intraorganic vessels of the liver in acute experimental peritonitis].

Structural pathology and hemodynamics in the livers of 110 white rats were studied histologically, electron microscopically and histoautoradiographically during 5 days since the onset of acute experimental peritonitis. This was accompanied with distinct structural and functional derangement of histohematic barrier along with hepatic hemodynamic disturbances dependent in severity on both fecal suspension quantity and AEP course and stage. Pathologic and compensatory-adaptive reactions profile was established for the animals intrahepatic circulation. Polymorphism of the vascular affections underlies the emergence of the two morphogenetic mechanisms responsible for impairment of hepatic parenchyma: 1) a direct action of toxic substances on hepatocytic cellular membranes, 2) disordered circulatory-hypoxic effect based on pronounced DIC-syndrome and thrombosis. The former mechanism gives rise to disseminated necrosis of hepatocytes, while the latter entails the onset of intralobular necrotic foci, typical for the reactive and toxic stages of acute peritonitis, respectively.

Acute Disease↗

PubMed1987

[Changes in the lung parenchyma in the early phases of bacterial toxemia and acute diffuse peritonitis in an experiment].

A comparative study of changes in the pulmonary parenchyma of guinea pigs with toxemia caused by intraperitoneal injection of staphylococcal toxin or Pseudomonas aeruginosa endotoxin and in those with peritonitis induced by i. p. injection of a suspension of human or guinea-pig feces has shown the changes to be rather similar in these conditions. In particular, as soon as 10 min after the onset of disease, signs of damage were detected in lung cells and capillary endotheliocytes of the blood-air barrier; later on, microthrombi were detected in pulmonary capillaries. In guinea pigs with feces-induced peritonitis, microfoci of pneumonia were seen. Following the injection of human fecal suspension, early signs of the sludge syndrome were present. The observed changes resembled those described for the adult respiratory distress syndrome (shock lung).

Animals↗

PubMed1983

[Functional and structural changes in the small intestine during experimental hypercholesteremia].

Functional and structural changes that occurred in the small intestine and liver of rabbits with alimentary hypercholesterolemia have been studied. Maximal rise of peripheral blood cholesterol after a single exposure to cholesterol was coupled with an increased penetration of chylomicrons and low and very low density lipoproteins from the intestine to the circulation. The decrease of cholesterol excretion along the whole length of the small intestine was accompanied by activation of the release of high density lipoproteins into the blood outflowing from the intestine. The decay of chylomicrons in the liver was restricted during the first days of hypercholesterolemia. Cholesterol concentration in the bile was decreased. The microvessels of the small intestine demonstrated the dilatation of the postcapillary-venular component erythrocyte aggregates and capillarostases.

Animals↗

PubMed1982

[Reaction of rat peritoneal mesothelial cells in aseptic and bacterial peritonitis].

Transmission and scanning electron microscopy were used to examine mesothelial cells of the rat peritoneum in aseptic peritonitis caused by intraperitoneal starch injections and in bacterial peritonitis induced by injury to the large intestine. Active contraction of the mesotheliocytes was recorded in early stages of both the types of peritonitis. In aseptic peritonitis, that contraction was replaced by relaxation of the cells, whereas in bacterial peritonitis, by dystrophy and desquamation.

Animals↗

PubMed1982

[Morphology of the parietal peritoneum and peritoneal exudate in peritonitis].

Biopsies of the peritoneum and cells of peritoneal exudate were examined in 36 patients with various phases and extension of acute purulent peritonitis. In 34 of them biopsy was taken before and after therapeutic treatment with low-frequency ultrasound. In all the cases the material was examined by light microscope, in 9 by means of transmission electron microscopy, in 2 by means of scanning electron microscopy. The peritoneum of 3 patients undergoing planned operation was studied as the control. It was shown that on the first day of peritonitis development there occurred active contraction of endotheliocytes of peritoneal microvessels with divergence of intercellular contacts resulting in sharp extravasation of the liquid, condensation of the blood formed elements, and formation of stases and microthrombi. The latter prevented marginal stay and emigration of leukocytes. Ultrasonic treatment facilitated the destruction of microthrombi and was accompanied by intensive leukocyte migration.

Adolescent↗

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↗

PubMed1978

[Routes of E. coli 055 bacterial penetration through the intestinal wall in gnotobiotic and ordinary animals].

Peculiarities of permeability of intestinal barrier in germfree animals for enteropathogenic E. coli 055 were studied. Both germfree and conventional guinea pigs and rats were used. An increase of bacteriemia was revealed in gnotobiotes during the first day of oral E. coli 055 monocontamination; bacteriemia was transient in conventional animals. Under electron microscopy alterations of intercellular contacts and formation of spaces between enterocytes containing numerous microorganisms were found in the intestinal mucous membrane in gnotobiotes. Also more pronounced changes of microvessels of the intestinal mucous membrane were discovered in gnotobiotes. The processes of ingestionan and digestion of Escherichia coli by enterocytes and leukocytes were noted in conventional animals. The revealed derangements of the intestinal barrier in gnotobiotes explain the cause of higher bacteriemia in germfree animals. An important role of the microbial factor in the formation of intestinal barrier is indicated by the data obtained.

Animals↗

PubMed1974