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Biomedical subjects

V I Iakovleva

Publications and source records attributed to V I Iakovleva.

At least 19 recordsLinked to original sources
PubMed1990

[Experience in the surgical treatment of chronic suppurative lung disease in children].

UNLABELLED: Operations were performed on 750 children with cystic hypoplasia and dysontogenetic and acquired bronchiectases. The operation volume: pulmonectomy, lobectomy, combined resections, resection of pulmonary tissue with extirpation of bronchi, extirpation of bronchi. COMPLICATIONS: atelectasis, pneumonia, intrapleural hemorrhage were encountered in 87 (11.6%) children. Six (0.8%) children died. Recurrent or residual bronchiectases were found in 27 children, 18 underwent a second operation. Recurrences were encountered mainly in children with dysontogenetic bronchiectases.

Bronchi↗
PubMed1989

[The effect of composition and ionic strength of external solution on the aspartate-ammonia lyase and fumarate hydratase activity in Escherichia coli cells].

It was found that the nonspecific effect of ionic strength of the external solution on the enzymatic activity of E. coli cells consists in rapid changes in the permeability of cell membranes interacting with the substrate. This effect depends on the initial substrate concentration, i.e., ionic strength of the external solution, and is maintained for some time as the substrate concentration decreases. Chloramphenicol, a protein synthesis inhibitor, and sodium azide, a respiration inhibitor (300 micrograms/ml and 200 microM, respectively) do not change the enzymatic activity of E. coli cells during the synthesis of L-aspartic and L-malic acids from fumaric acid. The kinetic equations of L-aspartate and L-malate synthesis are described by equations of zero and intermediate (between zero and first) order, respectively.

Ammonia-Lyases↗
PubMed1981

[Kinetics of fumarate hydratase reaction catalyzed by free cells of Escherichia coli].

The kinetics of the fumarate hydratase (fumarase) reaction catalyzed by the cells of E. coli strain 85 at high concentrations of the substrate (potassium fumarate) were studied. An automatic procedure for determination of the reaction product--malonic acid--including the use of commercial malate dehydrogenase from porcine heart was developed. The fumarate activity of bacterial cells was studied at different concentrations of the substrate and at different pH values with intact and disrupted cells of E. coli 85 used as the enzyme source. The rate of the fumarase reaction in the E. coli cells was shown to depend on the diffusion and transport processes of the reagent transfer across the cell wall and the cytoplasmic membrane of bacterial cells. The pH optimum of the reaction in free E. coli cells (8-9) and the rate of malonic acid synthesis from potassium fumarate under optimal conditions, which varies within the concentration range of (6--13) x 10(-5) mkmole per mg of protein depending on the quality of cell, were determined.

Escherichia coli↗
PubMed1980

[Kinetics mechanism of L-aspartate synthesis from ammonium fumarate catalyzed by free and immobilized cells of E. coli].

A detailed study of kinetic peculiarities of the L-aspartate-ammonium-lyase reaction catalyzed by free and immobilized E. coli 85 cells incorporated into polyacrylamide gel, has been carried out. The effects of different types of bacterial cell "activation", substrate concentration and temperature on the reaction rate have been investigated. It was shown that the rate of the reaction is limited by the rate of the substrate transfer through the cell and cytoplasmic membranes and at sufficiently high values of the substrate can be described in terms of zero-order kinetics with respect to substrate and reaction products concentrations A kinetic model based on the diffuse and transfer processes of translocation of the aspartate-ammonium-lyase reaction participants through the cell and cytoplasmic membranes is proposed.

Aspartic Acid↗
PubMed1980

[Isolation, purification and some properties of tyrosine-phenol-lyase from Citrobacter freundii cells].

A new procedure for isolation of tyrosine-phenol-lyase from the cells of C. freundii strain 62 allowing to obtain a highly purified enzyme with a high yield at a reduced time expenditure has been developed. The procedure described differs from the well-known method for isolation of the enzyme from the cells of Escherichia intermedia and Erwinia herbicola. Some properties of the enzyme from C. freundii 62, e.g. stability, dependence of the enzyme activity on some mono- and bivalent cations and pH- and temperature dependences of the enzyme have been studied. It was shown that the enzyme is activated by NH4+, K+, Na+ and is inhibited by Ca2+, Cu2+ and Mg2+. The enzyme loses up to 50% of its activity upon storage in glycerol with 2-mercaptoethanol during 1,5 months at -18 degrees.

Cations, Divalent↗
PubMed1979

[Dependence of the rate of aspartate ammonia-lyase reaction catalyzed by free and immobilized cells of E. coli on temperature and preliminary thermal treatment].

The effects of temperature (45--55 degrees) and duration of thermal treatment on the L-aspartase activity of free and immobilized on polyacrylamide gel cells of E. coli, strain 85 were studied. It was found that preliminary thermal treatment of the cells at 50 degrees for 40--60 min is optimal for a high aspartase activity. Within the temperature interval of 20--55 degrees the temperature dependence of effective rate constants of L-aspartate synthesis obeys the Arrhenius equation, whereas the effective energy of activation is decreased from 12,6 to 3,6 kcal/mole, when the "activation" of the cells shows an increase.

Ammonia-Lyases↗
PubMed1979

[Kinetics of the aspartate-aminotransferase reaction catalyzed by free and immobilized cells of E. coli].

The kinetics of the aspartate-aminotransferase reaction were studied, using free and immobilized cells of E. coli, strain 85 as an enzyme source. It was shown that the reaction is limited by mass transport of the reagents through the bacterial cell membrane even at high concentrations of the substrates in the surrounding solution. The polyacrylamide gel-incorporated cells of E. coli, strain 85 catalyze the aspartate-aminotransferase reaction more effectively as compared to free or destroyed cells. In the latter case the reaction is characterized by the following kinetic parameters: the effective values of the stationary rate of the product accumulation and its stationary efflux from the cell are equal to (15,37 +/- 0.4) . 10(-6) mole/s/mg of protein and (3,01 +/- 0,8) . 10(-20) mole/s per 1 cell. respectively. The steady-state constant for glutamate synthesis from aspartic acid is equal to 0,22--0,23.

Aspartate Aminotransferases↗
PubMed1977

[Dynamics of lipid concentration changes in the livers of rats on biosatellites "Cosmos-605" and "Cosmos-782"].

Histological and histochemical investigation was carried out with rat liver specimens taken 9-11 h (from 6 rats), 24 (from 7 rats), 48 h (from 8 rats), and 25 (from 5 rats) and 27 days (from 7 rats) after the completion of 19.5- and 22.5-day of space bioflights in "Cosmos-605" and "Cosmos-782". The same number of specimens was investigated from corresponding models of the experiments carried out in the laboratory and from the control rats. The investigations demonstrated that in the rats sacrificed during the first two days, and in 25 and 27 days after the completion of the flight, no morphological changes developed in comparison with the control and with the animals from the laboratory experiments. Only some fluctuations in lipid content could be noticed in connection with the time of samples taking after the completion of the experiments. The greatest amount of lipids in the liver was observed in the rats sacrified 9-11 h after the completion of the flight, in 24 h the lipid level was still rather high, and in 48 h there was a tendency to their decrease. In 25 and 27 days the livers of the animals from the experimental group did not differ in their lipid content from those of the control animals. The changes in the lipid content observed in the liver during 8-48 h after the flight completion and during the period of afteraction indicate the reversibility of the adipose infiltration process, connected with lipid mobilization, dependent on stress-reaction.

Animals↗