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Biomedical subjects

G A Davydova

Publications and source records attributed to G A Davydova.

10 recordsLinked to original sources
PubMed2005

Factors affecting survival of reconstructed mouse embryos after nuclear transfer.

Reconstruction of mouse embryos was performed by injection of donor genetic material from differentiated cells of various types (cumulus cells, cardiomyocytes, and epithelial cells) into recipient cells (mature oocytes and zygotes). A medium for microsurgery was selected, which enhanced survival of both embryonic and somatic cells during the reconstructive manipulations. Special preparation of somatic cells to transplantation was carried out, which employed factors synchronizing the cells in a certain phase of the cell cycle in order to enhance their capacity to maintain the development of reconstructed embryos. The processes of nucleus reprogramming in specialized cells under the action of cytoplasmic factors of oocytes and zygotes were examined. During in vitro culturing of reconstructed embryos, the most successful development was observed in embryos implanted with donor material from cumulus cells. Mouse embryos reconstructed with a certain genome and subsequent production and use of stem cells are considered as the model system for developing the basic principles of replacement therapy.

Animals↗
PubMedDate not supplied

[Hyperlipoproteinemias and proteinase inhibitor balance in patients with proliferative diabetic retinopathy with solid exudates in retina].

Studies of lipid metabolism and proteinase inhibitor balance in the blood of patients with proliferative diabetic retinopathy (PDR) revealed hyperlipoproteinemias (HLP) in 61%. Type IIa HLP predominated (32%), type IV HLP were diagnosed in 23%, and type IIb in 7% of cases. Solid exudations in the retina were 7 times more frequent in patients with type IV HLP and 5 times more frequent in those with type IIb HLP than in patients without HLP. The most expressed shifts of proteinase inhibitor balance towards increase of trypsin-like activity, which was not compensated for by the antitryptic potential, were observed in the same two groups. The data indicate that PDR patients with types IIb and IV HLP with increased blood proteolytic activity not compensated for by inhibitors are at a high risk of developing solid exudations in the retina. Therefore individual drug correction of lipid metabolism and proteinase inhibitor balance is recommended for maintaining visual function in diabetics. The treatment should be based on the results of clinical and biochemical studies.

Adult↗
PubMedDate not supplied

[Parameters of blood proteinase inhibitor balance and hyperlipoproteinemia in patients with proliferative diabetic retinopathy with vitreous hemorrhage].

The parameters of proteinase-inhibitor balance and lipid metabolism were studied in the blood of patients with proliferative diabetic retinopathy. Metabolic disorders in patients with proliferative diabetic retinopathy with hemophthalmia are characterized by a notable increase in the activities of trypsin-like enzymes and alpha 2-macroglobulin level and normal activity of alpha 1-antitrypsin and shifted lipid metabolism parameters characteristic of types IIb and IV hyperlipoproteinemia. These data indicate a necessity of monitoring lipid metabolism and proteinase-inhibitor balance in patients with diabetic retinopathy in order to detect subjects at a high risk of hemophthalmia and timely start drug correction for preventing this complication.

Adult↗
PubMedDate not supplied

[A study of the effect of irradiation hardness on the properties of the fluoropolymeric matrix modified by polyanionic biologically active substances].

The properties of a synthetic substrate responsible for the behavior of substrate-dependent cells in the culture were studied. The effect of the composition of a system water-soluble biopolymer (sodium alginate or methyl cellulose)-synthetic latex SKF-26 and the effect of various types of radiations on its biophysical properties were studied. The results obtained indicate that the addition of water-soluble biopolymeric additives to synthetic polymeric films improves the adhesion of cells to the substrate, the adhesion being closely related to the concentration of additives. It was found that the modification methods that determine changes in the charge of the substrate affect the capacity of different cell types for adhesion and proliferation. It was also found that the hardness of irradiation does not affect the vapor permeability and the extent of film swelling.

Alginates↗
PubMedDate not supplied

[Oxidation of p-nitrobenzylamine and p-dimethylaminomethylbenzylamine by amine oxidases from the human placenta and serum].

Oxidation of p-nitro- and p-dimethylaminomethyl derivatives of benzylamine, catalyzed by amine oxidases from human placenta and blood serum, was studied. The amine oxidase activity was estimated by means of a spectrophotometric procedure involving measurement of aldehyde formed during the reaction after extraction with hexane. For extraction of benzaldehyde and p-nitrobenzaldehyde in the samples HCl was added up to the concentration of 0.17 M and for extraction of p-dimethylaminomethyl benzaldehyde--NaHCO3 up to the 0.5 M concentration. The reaction products were extracted with a yield of 94%, 83% and 78% respectively; molar extinction coefficients for aldehydes at the maximal absorption were equal to 13,080 (241 mn), 16,520 (258 nm), and 11,547 (248 nm), respectively. Analysis of the oxidative reactions using inhibitors Lilly 51,641, deprenyl, aminoguanidine and semicarbazide showed that monoamine oxidase of the A type (95%) and benzylamine oxidase (7%) catalyzed oxidation of 0.1 mM p-nitrobenzylamine in mitochondria and microsomes but oxidation of the substrate at 1 mM concentration was catalyzed by monoamine oxidase of the B type (20% in mitochondria and 35% in microsomes). In the soluble fraction oxidation of p-nitrobenzylamine was catalyzed mainly by diamine oxidase (55%); monoamine oxidase of the A type catalyzed oxidation of 30% of the amine, benzylamine oxidase-15%. The molecular activity of the mitochondrial monoamine oxidase of the A type with p-nitrobenzylamine as a substrate was equal to 61 nmol of the product per 1 mole of the enzyme per 1 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Amine Oxidase (Copper-Containing)↗
PubMedDate not supplied

[Effect of new 2-propinylamine derivatives on mitochondrial monoamine oxidase activity].

New derivatives of 2-propinyl amine were studied as possible inhibitors of mitochondrial monoamine oxidases (MAO) from rat liver and brain tissues. Kinetics of inhibition of the MAO activity (A and B types) is described for one of the substances studied -- N-(8-quinolyl methyl)-N-methyl-2-propinyl amine. Interaction of N-(8-quinolylmethyl)-N-methyl-2-propinyl amine with MAO of the A type (serotonin as a substrate) and of the B type (beta-phenylethylamine as a substrate) was studied by the kinetic method, which enabled to determine and quantitatively estimate the steps of enzyme-inhibitor complexes formation. The inhibition of the mitochondrial MAO A and B types by the substance was shown to include the steps of formation of dissociating enzyme-inhibitor intermediates with the subsequent irreversible modification of them. The data on K1 values, estimated in experiments with serotonin and beta-phenylethylamine as substrates, show that the affinity of N-(8-quinolyl methyl)-N-methyl-2-propinyl amine towards MAO of the A type was 10-fold higher than the affinity towards MAO of the B type. The rates of these complexes conversion into irreversibly blocked forms of the MAO A and B types was found to be similar.

Alkynes↗
PubMedDate not supplied

[Results of the use of vasoactive preparation pikamilon in pigmented retinal abiotrophy].

Eighty patients with pigmented retinal abiotrophy (PRA) and 20 controls were examined. The perfusion pressure and arteriovenous coefficient are markedly reduced in patients with stages 1-2 PRA, in comparison with controls. Deterioration of the visual function in patients with stages 3-4 PRA vs. that in stages 1-2 was associated with a more marked reduction of the hemodynamic parameters and the status of ocular vessels. Pikamilon therapy in a dose of 2 ml of 10% solution once a day intramuscularly for 10 days led to improvement of the visual function and ocular hemodynamics in patients with PRA. Treatment efficacy was higher in patients with disease stages 1-2. Pikamilon is recommended for the treatment of patients with PRA.

Adolescent↗