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Biomedical subjects

V P Shevchenko

Publications and source records attributed to V P Shevchenko.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Blood thymus hormone content in different types of neoplastic process and its changes as a result of chemotherapy and surgical removal of tumors].

Levels of thymic hormones in blood serum were found to decrease during the development of Guerin's carcinoma, methylcholanthrene- and DMBA-induced carcinogenesis, soft tissue sarcomas, mammary cancer, in children with tumors of the urinary-genital tract, that evidences for the suppression of the thymic endocrine function in neoplastic processes. A decrease in the level of substances, active in the test under study is not revealed in patients with different forms of leukemias. The tumour elimination normalizes the thymic endocrine function, while multiagent chemotherapy increases the insufficiency. The data obtained suggest the immunotherapy for malignant neoplasms with thymic hormones.

Adult↗
PubMed1989

[Preparation and properties of prostaglandin D2 labelled with tritium with high molar radioactivity].

Kinetic parameters of enzymatic and non-enzymatic transformations of [3H]prostaglandin H2 (PGH2) were determined; the maximum yield of [3H]PGD2 being obtained at the keobs/koobs ratio equal to 10. The two-stage enzymatic synthesis of [3H]PGD2 with high molar radioactivity (3.15 TBq/mmol) from [3H]arachidonic acid carried out. Its identity in properties to the natural PGD2 was shown in experiments on the inhibition of ADP-induced aggregation of thrombocytes and on enzymatic oxidation with 15-hydroxyprostaglandin dehydrogenase.

Adenosine Diphosphate↗
PubMed1988

[Directed biosynthesis of prostaglandin F2 alpha multiple labeled with tritium].

By selecting specific activators of PGF reductase and determining their optimal ratio, we have performed the directed biosynthesis of PGF2 alpha with a 45-50% yield. With the use of [5,6,8,9,11,12,14,15-3H8]arachidonic acid, multiple-labelled PGF2 alpha with molar radioactivity 6.1 TBe/mmol has been synthesised.

15-Oxoprostaglandin 13-Reductase↗
PubMed1988

[Synthesis of tritium-labelled prostaglandin E1 and its binding to human platelets].

A method has been developed that makes it possible to obtain [5,6-3H2]PGE1 with a yield of 35% and a molar radioactivity of 1.7-1.8 TBq/mmol. The binding of [5,6-3H2]PGE1 to native platelets proved to be specific, saturating and reversible. It is characterized by low values (approximately 10(-9) M) of dissociation constants for high-affinity sites, correlates with the inhibition of ADP-induced aggregation of platelets and can be considered as receptor binding. Specific binding of 10 +/- 2 molecules of PGE1 with one platelet was found to cause 50% inhibition of the ADP-induced aggregation.

Adenosine Diphosphate↗
PubMed1988

[Chemical synthesis of tritium-labeled prostaglandins A, B and F].

Formation of prostaglandins A, B and F from prostaglandin E has been studied. Synthesis of tritium-labelled prostaglandins A1, A2, B1, B2, F1 alpha, F2 alpha, F1 beta, F2 beta of high molar radioactivity from highly labelled PGE1 and PGE2 is described.

Chemical Phenomena↗
PubMed1986

[Induction of substances with thymosin-like activity and the potentiation of interferonogenesis in the mechanism of prodigiozan inhibition of 3-methylcholanthrene-induced blastomogenesis].

It is shown that prodigiosan is an inductor of synthesis of the substances with the thymosin-like activity. The suggestion about inhibition of 3-methylcholanthrene-induced blastomogenesis by prodigiosan which is mediated by the substances with the thymosin-like activity and interferon is discussed. We present the hypothetical diagram of the development of the above mentioned mechanism. The significance of the obtained findings for elaboration of the immunotherapy is discussed.

Animals↗
PubMed1985

[Synthesis of tritium-labeled N,N-dimethyl-2-phenylaziridinium and its reaction with acetylcholinesterase].

The synthesis of tritium-labeled N,N-demethyl-2-phenylaziridinium has been described. The specific radioactivity of the product obtained was 1,06 TBq/mmole. Kinetics of incorporation of this radioactive label into acetylcholinesterase of cobra venom (Naja naja oxiana) has been studied at 1,05 mM ligand concentration (25 degrees C, pH 7,50. 0,15 M phosphate buffer). Under these conditions two molecules of the radioactive label have been found to react with the enzyme. One molecule incorporates fast with half-life of 4,8 min, not affecting the enzymatic activity. Incorporation of the second label is a slow reaction with half-life of 6 hr and leads to complete inactivation of acetylcholinesterase. Molecular mass of the modified enzyme is 63 +/- 4 kDa and coincides with that of native one.

Acetylcholinesterase↗
PubMed1983

[Labeling of steroids with tritium].

Conditions have been elaborated for the tritium labeling of some steroids to a molar activity of the order of 1 TBk/mol by heterogeneous catalytic isotopic exchange. For steroids without a keto group, isotopic exchange with gaseous tritium is most effective in neutral solvents, whereas for steroids with a keto group an alkaline medium is preferable. At certain pH values it was possible to void hydrogenation of the double bonds in the compounds.

Chemical Phenomena↗
PubMed1982

Role of gangliosides in reception of influenza virus.

The ganglioside composition of Ehrlich ascites carcinoma (EAC) cells and the role of the individual gangliosides in binding and penetration into the cell of influenza virus were determined. EAC gangliosides identical with or close to GM3, GM2, GM1, GT1a and GT1b were characterized by thin-layer chromarography, compositional analyses, methylation analysis and mass-spectrometry. The ganglioside uptake capacity of native and neuraminidase-treated EAC cells was studied with tritium-labeled gangliosides of definite structure and the binding of influenza virus to cells was determinated by using [3H]uridine-labeled virus and by hemagglutination studies. Treatment of the cells with Vibrio cholerae neuraminidase largely decreased binding of the virus. Exogenous gangliosides with a terminal galactose unit or a penultimate galactose masked by neuraminic acid were able to restore the virus-binding capacity of neuraminidase-treated cells, however, the main ganglioside of EAC cells, GM2, which carbohydrate chain is terminated by N-acetylgalactosamine, was completely ineffective. The common carbohydrate sequence of the gangliosides showing binding activity (formula; see text) is proposed to be the main recognition structure of the influenza virus receptor on the surface of EAC cells. Penetration of labeled influenza virus into the nuclei of EAC cells was evaluated by measuring the radioactivity of the nuclei of neuraminidase-treated ganglioside-loaded cells after exposition to the labeled virus. Of all gangliosides tested only trisialogangliosides of the GT1b type were able to induce increased entry of the virus into the cells and accumulation of its radioactive component into the nuclei. It is suggested that GT1b gangliosides react specifically with the virus protein responsible for membrane fusion (apparently the hemagglutinin HA2 subunit) and thus are involved in virus penetration and delivery of the virus genome to the nuclei.

Animals↗
PubMed1979

[Sutureless ultrasonic hermetic sealing of the bronchial stump after experimental and clinical lung resection].

The authors have shown the possibility of the hermetization of the bronchial stump after resection of the lung through the use of osteocyanacrlic mass treated with ultrasound. A small number of clinical reservations, however does not allow to recommend the method for a broad use in the clinical practice. Nevertheless the authors believe the idea of ultrasound sutureless closure of the bronchial stump to be a promising one and needing further studies.

Animals↗