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Biomedical subjects

E M Kogan

Publications and source records attributed to E M Kogan.

At least 55 records · Page 3Linked to original sources
PubMed1975

[Dynamics of Ca2+ transport in rat liver mitochondria in anoxia].

Tetracycline was used as a fluorescent test-antibiotic for Ca2+ ions in rat liver mitochondria. Incubation of the isolated mitochondria under anaerobic conditions at 20 degrees C resulted in a rapid (in 30-min) loss by the mitochondria of the property to accumulate Ca2+. Disturbances of the mitochondrial Ca2+-accumulating property during the survival of the liver developed much more slowly (it took over 2 hours) and were not monotonous; the maximal values were recorded during the 5th-10th and the 60th minutes of survival.

Animals↗
PubMed1975

Double-stranded complex of polyguanylic and polycytidylic acids and its antiviral activity in tissue culture.

The antiviral activity and conditions of formation of the most active double-stranded complexes of synthetic homopolynucleotides, polyriboguanylic and polyribocytidylic acids, were studied on the model of primary trypsinized chick embryo cells and RNA-containing viruses. The (poly G).(poly C) complex was very active against the viruses tested; their replication in cell cultures was inhibited completely. The antiviral activity of the (poly G).(poly C) complex increased markedly in the presence of diethylaminoethyl- (DEAE-) dextran. After treatment with 1 mug/ml of (poly G). (poly C) for 1 hour in the presence of 100 mug/ml DEAE-dextran, the cell sheet remained protected for 5-7 days. Preparations of (poly G).(poly C) obtained under optimal conditions were as active as (poly I).(poly C) complexes and exceeded them markedly in the level of the therapeutic index which under the present experimental conditions was 5-10 times 10(3) for (poly G).(poly C). Highly purified homopolymers with sufficiently high molecular weight must be used for production of active and stable (poly G).(poly C) complexes.

Animals↗
PubMedDate not supplied

[The use of computer morphodensitometry in modern molecular diagnostic methods].

Technologies based on the use of polymerase chain reaction, in particular IS PCR are widely used now. However, wide introduction in clinico-laboratory practice of these methods requires: increase of reliability of the accepted decisions, improvement of the image for revealing more fine distinctions of objects, increase of quality of the obtained information, automated registration of results of the analysis. The application of original digital image analysis, adapted to specificity of biomedical objects--morphodensitometry--allows to solve successfully the following tasks: to optimisze conditions of IS PCR realisation on the basis of use of quantitative opticogeometrical parameters, quantitatively and subpopulistically to characterize a degree of infected cells with viral infection, and also nucleuses of cells, that is especially actual for introduction of molecular-genetic methods in clinico diagnostic practice and, automatically to register results of the analysis. Thus, employment of morphodensitometry can be very important in genediagnostic and also gene therapy.

Animals↗
PubMedDate not supplied

[The use of the DiaMorf (Russia) computer-programmed unit for evaluating the effect of steroids and cytostatic agents on cultured cells].

The effect of some steroid hormones and their synthetic analogs--dexamethasone, estradiol, progesterone, testosterone, and cytostatics--on the fibroblast nuclei in a monolayer culture was studied. Their proliferation was studied at the same time by the radioindicator method. The method of computerized morphodensitometry with the use of the apparatus-programmer complex DiaMorf (Russia) showed that the compounds under study induce reorganization of interphase chromatin of fibroblast nuclei over the molecules, the amount of which may be recorded by means of the computer system of analysis of cell and tissue images.

Algorithms↗
PubMedDate not supplied

[Hydrolysis and the inactivation of double-stranded polyribonucleotides by monkey blood serum].

The effect of Macaca rhesus monkey blood serum on double-stranded polyribonucleotide complexes poly (I).poly (C), poly (G).poly (C), and poly (G,I).poly (C) was studied. The poly (I).poly (C) complex was found to be the most sensitive to hydrolysis as indicated by a decrease of the molecular weight, accumulation of acid-soluble products and a sharp decline of the antiviral and interferon-inducing activities in tissue culture after incubation of the complex in the presence of the serum at 37 degrees C for 1 hour. The poly (G).poly (C) complex was the most stable, and retained its original activity in tissue culture and a high molecular weight after 3-hour incubation with the serum. The interferon-inducing activity of all the complexes under study assayed by intravenous injection in a dose of 2 mg to M. rhesus monkeys was similarly low irrespective of their sensitivity to the serum. Conjectural species features of the interferon induction system in monkeys are discussed.

Animals↗
PubMedDate not supplied

[Use of automatic cytophotometric analysis for assessing the hepatotropic action of ethanol].

It has been shown in experimental chronic intoxication that there is a close correlation between the dose of ethanol, microscopic appearance of the liver, the content of DNA, RNA, protein, glycogen in hepatocytes and structural parameters of nuclear chromatin of these cells. It is concluded that automatic cytophotometric analysis of the structure of hepatocyte nuclei holds promise for an accurate quantitative evaluation of the hepatotropic action of chemical substances and drugs.

Alcoholism↗
PubMedDate not supplied

[Dependence of the antiviral activity of the poly(G).poly(C) complex on the size of the continuous poly(C)segments].

Modification of poly(C) by various frequency treatment with adenosine non-complementary to guanosine has produced poly(G) X poly (C.A) complexes with continuous double-stranded areas the length of which is determined by C/A ratio. Studies of the antiviral activity of poly(G).poly(C,A) complexes with C/A from 10:1 to 90:1 and poly(G).poly(C) in vesicular stomatitis virus-infected chick embryo cell cultures and in experimental tick-borne encephalitis of mice demonstrated that the maximum activity is achieved at an average lengths of double-stranded areas of 90 nucleotide pairs. At the same time, a low but statistically significant antiviral activity is observed at a length of double-stranded areas of 10-30 nucleotide pairs.

Animals↗
PubMedDate not supplied

[Evaluation of the size of the continuous poly(G) site necessary for the biological activity of the poly(G).poly(C) complex].

On the basis of synthesis of a series of poly(G, A).poly(C) copolymers with changing G:A ratio from 15:1 to 90:1 and trials of their biological activity in comparison with poly(G).poly(C), the size of poly(G) in it was evaluated within the range of a continuous double-stranded area necessary for the activity. The antiviral activity close to that of poly(G).poly(C) in experimental tick-borne encephalitis of mice and vesicular stomatitis virus infection of chick embryo cells was found only in poly(G,A).poly(C) complexes with a G:A ratio equal to or higher than 90:1. Consequently, the high activity of poly(G).poly(C) is present at an average length of poly(G) equal to 90-100 nucleotides within the limits of the continuous double-stranded area.

Animals↗