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Biomedical subjects

E M Kogan

Publications and source records attributed to E M Kogan.

At least 19 recordsLinked to original sources
PubMed2005

[Statistical characteristics of inhomogeneities of protein and chromation networks].

Natural textures (networks) are observed in many cases: the inter-cellular contact sites, endoplasmic reticulum membranes etc. The vast amount of experimental data was analyzed to produce the distribution histograms for the length of the segments in the protein and chromatin networks of different origin. The networks both from the eukaryotic cells and nucleis, as well as from E. coli and viruses are presented. Statistical analysis demonstrated that all experimentally observed histograms fit to the following formula: F(x) = (5(5)[4]) x x(4)x exp(-5x) where x =l/ , l- length of the network segment, and </> is the average length of the segment. In contrast to the Gaussian distribution, the distribution of the segments' lengths is markedly assymetrical. The shape of the distribution does not dependent on the origin of the analyzed network.

Animals↗
PubMed2000

[The use of in situ polymerase chain reaction for detection the intracellular localization of Mycoplasma hominis in cultured HeLa cells].

Mycoplasma hominis was incubated with HeLa cells up to 72 h. Infection of HeLa cells was estimated by in situ polymerase chain reaction with a subsequent use of computer digital image analysis for result processing. The localization of mycoplasma in the cell nucleus was demonstrated after a 48 h incubation. The quantity of infected HeLa cells was increased with time to make 58 and 75% on days 2 and 3, respectively. No M. hominis was found in the cytoplasma of HeLa cells.

HeLa Cells↗
PubMed1995

[Computed morpho-densitometry and its possibilities in experimental and clinical studies].

The paper deals with the automatic morphodensitometric analysis of various biomedical objects (such as interphase chromatin in the cellular nuclei of chondroblasts and lymphocytes or human peripheral blood, opacities in the lens of chick embryos. A complex algorhythm of computational image processing was created for submolecular restructuring of interphase chromatin cell nuclear examinations. It includes specific methods of staining and unifies different quantitative analytical methods: photometrical, geometrical, gradiental, informational, and statistical. The blood cells of the children who had received low-dose radiation were detected by employing a new method of TV image computational processing of DNA-stained lymphocytes. The approach demonstrated by this study provides a sensitive and meaningful mean for diagnosing human diseases and can be useful in the clinical setting.

Adolescent↗
PubMed1992

[A new method of a morphometric study of the kidney using a computer-assisted morphometric complex "Diamorph"].

The use of a computer--based morphometric complex "DIAMORPH" for automated morphometric analysis of renal glomeruli is described. By combining the principles of morphological and functional approaches to diagnosis with the capabilities of present--day research equipment, a new informative morphometric parameter--the extent of capillary--mesangium contact--has been identified. With this parameter and its derivatives, it has been possible to differentiate, in a statistically significant way (p less than 0.01), healthy subjects (controls) from patients with manifest diabetes mellitus of up to I year in duration who could not be distinguished through light microscopic or conventional morphometric studies.

Adolescent↗
PubMed1991

Biophysical studies of the modification of poly(rG) . poly(rC) by cisplatin. Relations to the biological activity of the complex.

The integrity of the double-stranded complex polyriboguanylic.polyribocytidylic acid [poly(rG).poly(rC)] modified by antitumour cis-diamminedichloroplatinum(II)(cis-DDP) was studied with the aid of differential pulse polarography and terbium fluorescence measurement. The modification was made to level corresponding to rb = 0.05 (rb is defined as the number of platinum atoms covalently bound per one nucleotide residue). Two modes of the modification of the polynucleotide complex were employed: The action of cis-DDP on poly(G) before formation of the complex with poly(C) and on the complex already formed from non-modified polynucleotides. It was shown that in the latter case modification disordered the integrity of the complex only negligibly. while in the former case the modification resulted in a noticeably more extensive disturbance of the double-stranded polynucleotide complex. Moreover, the modification of the complex (after its formation) at rb = 0.02 led to improved interferon-inducing and antiviral activity of poly(rG).poly(rC) tested on mice infected by influenza virus. It was suggested that the combined effects of interferon-inducing and antiviral activities of poly(rG).poly(rC) and antiviral activity of cis-DDP may result in an increased effect over and above what may be expected from the actions of the two modalities separately.

Antiviral Agents↗
PubMed1991

Biophysical studies of the complexes of polyriboguanylic acid with brominated and chlorinated polyribocytidylic acids.

Conformation of double-stranded complexes of polyriboguanylic acid with halogenated polyribocytidylic acid [poly(C)] was studied with the aid of differential pulse polarography, terbium fluorescence and circular dichroism spectrometry. It was shown that halogenation at C(5) of cytosine residues in poly(C) disturbed the ordered structure of the double-helical complex. In addition, this halogenation does not improve antiviral activity of the polynucleotide complex studied in the system of vesicular stomatitis virus and the cell culture of chicken embryos. It was concluded that the regularity of the secondary structure of synthetic RNAs might play an important role in the mechanism of biological activity of these biomacromolecules.

Biophysical Phenomena↗
PubMed1991

Modification of duplex poly(G).poly(C) by platinum (II) compounds.

The modification of the double-stranded poly(G).poly(C) complex by cis-diamminedichloroplatinum(II) was studied by two modes: the action of cis-DDP on poly(G) before formation of the duplex with poly(C) and that on the prepared duplex. It was shown that in the latter case modification disordered the integrity of the duplex only negligibly at rb less than or equal to 0.05 and led to improved interferon-inducing and antiviral activity tested on mice infected by Influenza and Herpes viruses.

Cisplatin↗
PubMed1990

[Morphometric characteristics of hepatocyte mitochondria during internal administration of boron-containing water].

The changes of hepatic mitochondrial cells were studied in white male rats during internal application of boron-containing waters, having 250 mg/l concentration of boron, but different ionic-salt basis. Mitochondrial hepatocytes and hepatic boron content relationships were established. It was shown that during boron accumulation in liver (15 applications) decreasing of mitochondrial size occurred, independently, of the type of boron-containing waters. During stable boron level and particularly during its excretion from organism (24 applications, 6 days aftereffect), increase of size of mitochondria and their ellipticity, change of configuration, that depend on the type of applied waters was shown.

Animals↗
PubMed1989

[Identification of digitonin binding sites on the plasma membrane of the rabbit aorta endotheliocytes].

Specific reagents comprising digitonin bound to latex spheres were used as visual markers for the detection of cholesterol sites on the endothelial cell surface by scanning electron microscopy. The distribution of latex markers in the plasmolemma of the endothelial cells was investigated. These markers have strong bonds with the ligands. This interaction guarantees high specificity of binding between labeled markers and cellular membrane cholesterol.

Animals↗
PubMed1988

[Regional characteristics of the organization of the aortic endothelium (a quantitative analysis)].

By means of SEM-analysis in 110 microphotos (from 14 aortas of white rats) with the aim to estimate heteromorphism of the thoracic part endothelium, quantitative characteristics of endotheliocytes have been studied in the ventral and dorsal surfaces, and also around the ostia of the intercostal arteries. For the quantitative analysis organization of the lines of the interendotheliocyte borders is taken into account. Endotheliocytes around the ostium are more elongated but occupy less area and have less straight contours in comparison with cells in other regions; they have also greater variability. Essential differences in arranging the endothelial cells into the layer on the ventral and dorsal surfaces of the aorta are revealed.

Animals↗
PubMed1987

The possibilities of the automated morphometry in the diagnosis of the hyperlipoproteidemia. Morphometry in the diagnosis of the hyperlipoproteidemias.

Following are the results of using the elaborated algorhythms of the structural analysis for the study of the form elements of the blood. A possibility was demonstrated to carry out a differential diagnosis of the familial hyperlipoproteidemia of the second type according to the quantitative structural parametres of the chromatin of the inter-phase nuclei of the lymphocytes of the peripheral blood. A method was developed of the automated morphometry of erythrocytes making it possible to assess the optical profile of erythrocytes according to 16 parametres. It was also registered a more vivid change of the curve of the membrane of the erythrocytes as compared with the Price-Jones spread on the same erythrocytes. With a help of a system of proposed parametres, which are 4-6-fold more informative and sensitive, than the traditional ones, it is possible to obtain the qualitatively new characteristics of the forms of erythrocytes, and not only their sizes.

Chromatin↗
PubMed1987

[Morphometric analysis of the toxic effect of ethanol on the structure of chromatin in interphase nuclei of rat hepatocytes].

A method of automated morphometric analysis of hepatic cell interphase nuclear chromatin (CHIN) structure was elaborated using scanning microspectrophotometer SMP-05 ("Opton", FRG). Liver sections of rats were used to investigate hepatic cell CHIN structure. The animals were administered ethanol intraperitoneally once per day within a month period in doses 4, 6, 8, 10 g/kg (1/3-4/5 LD50). Morphometric indexes indicating dose-dependent changes in hepatic cell CHIN structure are demonstrated. Statistical analysis of morphometric data has led to the conclusion that hepatic cell CHIN structural modification depends on two factors: ethanol damaging effect and hepatic cell regeneration.

Alcoholic Intoxication↗
PubMed1987

Complexes of polyriboguanylate with modified polyribocytidylate.

It was established minimal length of continuous poly(C) sequence of poly(G).poly(C) complex required for effective interferon induction by investigation poly(G).poly(C,A) with different molar ratios of C:A varying from 10:1 to 90:1. The minimum length of the double-stranded sequence of the macromolecule complex poly(G).poly(C) is equal to at least 90-100 nucleotides. The effect of 5-halogen-polyribocytidilates on the properties of the complexes has been also investigated.

Adenosine Diphosphate↗
PubMed1985

[Cytophotometric analysis of the chromatin structural conformity in interphase nuclei detected in UV light and by gallocyanine staining].

Geometric and optical parameters of chromatin of hepatocyte nuclei have been examined before (UV, lambda = 265 nm) and after gallocyanine staining. Quantitative parameters of the chromatin structure in the same nuclei measured in situ by a scanning microscope-photometer (step size 0.125 micron) before and after staining were equal. Tinctorial properties of chromatin granules (condensed part of the nuclear material) and its diffuse part were different. It is suggested that the difference between granules and the nongranular part of chromatin is not only of optical but also of chemical nature.

Animals↗
PubMed1985

[Quantitative informational estimation of the degree of liver damage on a model of chronic alcoholic intoxication].

In the rat liver at a chronic alcoholic intoxication produced with various doses of ethanol, a double phased picture of informational characteristics has been revealed in the cellular nuclei under a linear increase of the dose. An analysis of corresponding distribution of the hepatocytic nuclei has been performed according to their size and informational characteristics. On this base, the limiting dose of ethanol is estimated for development of the hepatic alcoholic lesion.

Alcoholism↗
PubMed1982

Membrane fluorescent probes for revealing lymphocyte population heterogeneity. II. T-and B-lymphocytes of human peripheral blood.

Lymphocytes of human peripheral blood were stained with a fluorescent probe 3-methoxybenzanthrone (MBA) and their fluorescence intensities measured using a cytofluorimeter. The lymphocytes are shown to be heterogeneous in fluorescence intensity. The fluorescence intensity of B-cells is 2-3 times higher than that of T-cells. Some data suggest that null-cells have an intermediate fluorescence intensity. Thus, with MBA it is possible to distinguish T- and B-lymphocytes in man.

Adult↗