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Biomedical subjects

E M Kogan

Publications and source records attributed to E M Kogan.

At least 37 records · Page 2Linked to original sources
PubMed1982

[Modification of the poly G-poly C complex by incorporation of adenosine in the purine chain].

Antiviral and interferonogenic activity of the complexes of poly(G,A) . poly(C) and poly(G) . poly(C) was studied in mice and cell cultures. Three out of 4 complexes of poly(G,A) . poly(C) had insignificant antiviral and interferonogenic activity in chick embryo cells. One of the complexes induced low levels of interferon production in mice and decreased the rate of their death from experimental forest-spring encephalitis. The activity of poly(G) . poly(C) in the above cell systems was much more pronounced. Unlike this complex, some complexes of poly(G,A) . poly(C) showed a noticeable activity in the cells of Primates. The effect of the noncomplementary base in the purine thread of poly(G) . poly(C) on its biological activity and nucleotide composition is discussed.

Adenosine↗
PubMed1982

[Sorption decholesterolization of the blood].

Results of haemosorption with the use of activated carbon IGI in patients with different diseases of the liver are given. It is shown that along with the toxic metabolites the method serves to remove a considerable quantity of cholesterol. It is surmised that haemosorption can become an effective method of control of hypercholesterolemia in atherosclerosis and its complications. The results of stand tests of sorbents specific for cholesterol are presented. A sorbent, synthesized from a metal-containing polymer was used for haemosorption in experiments on rabbits with alimentary hypercholesterolemia. Single haemosorption lasting 30 min led to a two-fold decrease of the cholesterol level in the blood and to a two-fold decrease of the damaged area in the aorta 4 weeks after operation.

Animals↗
PubMed1981

Membrane fluorescent probes for the demonstration of lymphocyte population heterogeneity. I T. and B lymphocytes of mice and rats.

Non-fixed lymphocytes of rats and mice were stained with the membrane fluorescent probe, 3-methoxybenzanthrone. The probe is capable of binding preferentially with lymphocyte membranes and fluoresces in the green spectral region. Microfluorometry of single cells showed that lymphocytes differ in all lymphoid organs and these may be a 3-10-fold variation in fluorescence intensity. Lymphocytes can be divided into two groups according to fluorescence intensity: "bright" and "dim". The proportions of "bright" and "dim" cells were determined in rats and mice for various lymphoid organs in the normal state, after thymectomy and cyclophosphamide treatment, and also after lymphocyte separation on a nylon wool column. In all cases the proportion of bright lymphocytes corresponded to the B-cell content, and the proportion of dim lymphocytes corresponded to the content of T-cells.

Animals↗
PubMed1981

[Mechanisms of disorders of the bioenergetic functions of mitochondrial membranes in hypoxia].

Evidence is provided that the following events take place in the cell in hypoxia and reoxygenation: expenditure of residual oxygen; a fall in the level of macroergic compounds; entry of calcium ions into the hyaloplasm both from the outside and from the mitochondria; activation of mitochondrial A2 phospholipase (possibly along with the other phospholipases); increase of membrane ion permeability (first phase of separation). This stage corresponds to the "irreversibility point" in cell damage because if the supply of oxygen to the cell is restored after it, the cell will not "recover" but, instead, will be damaged still more. This occurs as the result of active swelling of the mitochondria, inhibition of respiration and bioenergetic functions (the second stage of separation and loss of Ca-accumulating property by the mitochondria), irreparable damage to the cell with autolysis.

Calcium↗
PubMed1980

[Differences between lymphocytes revealed by membrane fluorescent probes].

Interaction of fluorescent probes of 3-methoxybenzanthrone (MBA), 4-dimethylaminochalcone (DMC), and of 1-anilinonaphthalene-8-sulfonate (ANS) with suspensions of rat thymocytes and Peyer's patches lymphocytes has been investigated. By means of the MBA, shown earlier to be a maker of B- and T-lymphocytes, it was established that thymus lymphocytes populations consisted mainly of T-cells (95 +/- 3%), and those of Peyer's patch lymphocytes of B-cells (68 +/- 9%). Definition of parameters of binding and fluorescence of ANS and DMC has shown different physical structure of the thymus and Peyer's patch lymphocyte membranes, resp. This is suggested by differences in binding constant of ANS, and in anisotropy of fluorescence of DMC. The difference in the number of binding sites gives evidence in favour of the fact that Peyer's lymphocytes have a greater membrane mass than thymocytes. T- and B-lymphocyte cells are likely to vary in their own structure and in the number of their membranes.

Anilino Naphthalenesulfonates↗
PubMed1980

[Action of histamine on the aortic endothelium].

Changes of the shape and surface of aortal endotheliocytes under the effect of histamine were studied by scanning electron microscopy. Incubation of fragments of the aorta in a histamine solution for 1 min results in changes of the nucleus-containing zone of some portion of the endotheliocytes into a spindle shape. The surface of the peripheral zone was characterized by the presence of spherical swellings. In some parts of the marginal zones of the cells there were numerous stomata of various sizes. Incubation of aorta for 5 min resulted in considerable alterations in the endotheliocyte stereoultrastructure. The nucleus- containing zones strongly protruded into the lumen. The cells became spherical. The peripheral zone was perforated by numerous stomata. The cell edges separated markedly at contact sites. The results suggest that the mechanism of the observed changes in the shape and surface of the cells may be associated with activation of the cytoskeletic complex (microtubules, microfilaments) under the effect of histamine.

Animals↗
PubMed1979

[Fluorescent probe-indicator of differences between T- and B-lymphocytes in the blood].

A new physico-chemical marker for the human peripheral blood lymphocytes was worked out. The lymphocytes were vitally stained with the fluorescent probe 3-methoxybenzanthrone and measured by microfluorometry. The blood lymphocytes population was found to be heterogeneous; this population consists of the two main groups of cells differing by the intensity of their fluorescence. By means of immunological lymphocyte fractionation it was shown that one of these cell groups was represented by T-lymphocytes, and the other one--by B-lymphocytes.

Adult↗
PubMed1978

Pulsed pattern of proliferation in liver parenchyma of young mice. Natural synchronization of DNA-synthesizing hepatocytes.

The present investigation is concerned with natural synchronization of DNA-synthesizing hepatocytes in the growing liver of young mice. It has been found that in individual specimens, 30--40% of all the parenchymal liver cells pass through the S phase within about 22 h. These cells are grouped into two large synchronous fractions, so-called "S-pulses". The time interval between the formation of these "S-pulses" is assigned by the duration of the S phase. It is shown that the maximum separate "S-pulse" involves 20% of the total hepatocyte population.

Animals↗
PubMed1978

[Antiviral activity of the complexes obtained at different ratios of complementary homopolyribonucleotides].

Antiviral activity of the complexes of synthetic polyribonucleotides, i.e. poly (I).poly (C) and poly (G).poly (C) obtained at non-equimolar ratios of homopolymers was studied. The system of chick embryon fibroblasts and horse Venezuellan eguine encephalitis virus served as the model. It was shown that the active and stable complexes poly (I).poly (C) and poly (G).poly (C) were formed at some excess of poly (C), i.e. at the ratio of poly G) or poly (I) to poly (C) equal to 40/60 to 20/80 molar per cent. The role of the excessive poly (C) in formation of the stable secondary structure of the nucleotide complexes and its significance as one of the means for affecting the fine structure of double-stranded RNA were discussed.

Animals↗
PubMed1976

[Morphofunctional express-diagnosis of liver conditons].

Methods of simultaneous detection of the vitally-essential indices of the hepatic tissue status by injecting neutral red vital dye into the portal vein are described. The liver tissue morphological status, the hepatic cell absorbing capacity, the blood microcirculatory efficacy and the pH shift were assessed on a histological preparation from the liver slice. The dye was extracted from the other portion of the same liver slice and the total amount of the dye absorbed was estimated.

Animals↗
PubMed1976

[Mast cells as regulators of tissue homeostasis and their place in the series of biological regulators].

The most essential features of the mast cell are continuous production (and partially also absorption from the environment), deposition, and secretion of the two groups of biologically active substances of the regulatory type: heparin and other acid clycosaminoglycanes, and also histamine and, probably, other biogenic amines. These substances are antagonists and have an influence on the homeostasis of the microregion (capillary-connective tissue-parenchyma) -- the main area of action of the mast cells. The mast-cell population is characterized, as compared with other cellular populations of the microregion, by a smaller size, greater morphological and functional diversity, functional duality (capability of producing both a positive and negative effect), and therefore possesses a number of essential properties the biological regulator should meet. The system of mast cells differs from the regulators of a higher order (the nervous and endocrine system) by a smaller radius of action and a greater simplicity of the structure, the latter manifests itself in equality of all its components. The conclusion is drawn that mast cells may be considered as the regulators of tissue homeostasis and a last link in the general reaction of adaptation at the cellular level.

Anaphylaxis↗