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Biomedical subjects

L A Litvinenko

Publications and source records attributed to L A Litvinenko.

10 recordsLinked to original sources
PubMedDate not supplied

[Changes in the system of antioxidant blood defence in newborns with different pathology].

Blood antioxidant enzymes (superoxide dismutase, catalase, ceruloplasmin) were investigated in gestational ages and diseases. Low activity of blood superoxide dismutase and catalase were observed in premature babies and in newborns after acute and chronic hypoxia. In hemolytic disease the activity of antioxidant enzymes of newborns was significantly higher than in healthy infants. This work demonstrates advantages of haemosorbtion compared to exchange blood transfusion. So the antioxidant activity in blood, decreased after blood transfusion, remained at a high level after haemosorbtion. Any deficiency of antioxidant enzymes in newborns may lead to toxyc oxygen effects. Antioxidants are potential therapeutic agents in the above mentioned conditions.

Adolescent↗
PubMedDate not supplied

[Effect of heavy water on the growth, glucose assimilation and stability of Escherichia coli to freezing-thawing].

Growth and resistance to freezing--thawing of Escherichia coli B-1640 were investigated during cultivation in synthetic media prepared with H2O and D2O. It is found that during cultivation in D2O the maximum specific growth rate decreases and the duration of the exponential growth phase increases. During the growth in D2O the glucose consumption rate drops in the exponential growth phase, the lactate content in the culture liquid is lower by two orders than that in H2O; the resistance to freezing--thawing is lower than that in H2O. After leaving the exponential phase the culture in D2O restores specific growth rate, glucose consumption rate and resistance to freezing--thawing up to the values obtained during the growth in H2O. The translation ability of ribosomes isolated from cells grown in D2O and H2O is the same. We conclude that the culture adapts to D2O during the exponential growth phase. It is suggested that during the adaptation the second carbon source is used which compensates the consequences of the disturbances of glucose metabolism and transport caused by deuteration of the cell content in the adaptation to D2O.

Adaptation, Physiological↗
PubMedDate not supplied

[Effect of hyperglycemia on the status of antioxidant protection of erythrocytes in children with diabetes mellitus and in vitro].

A study was made of changes in the activity of erythrocyte antioxidant enzymes (superoxide dismutase and catalase) with regard to the blood level of glucose in children with insulin dependent diabetes mellitus and in vitro. A total of 83 children aged 3 to 14 with insulin dependent diabetes mellitus and 10 healthy adults were investigated. Catalase activity did not change whereas superoxide dismutase activity in decompensation of disease was significantly lower than that in its compensation. Experiments in vitro revealed that glucose, added to erythrocytes of donors in the concentration of 20 mumol/l, caused a double decrease in the activity of both enzymes at 37 degrees C for 2 h as compared to control test values. Thus glucose was shown to be able to act as a modifier of enzymes, and the state of antioxidant protection of erythrocytes depended on its blood level.

Adolescent↗
PubMedDate not supplied

[Ultrastructure of Candida utilis during pulsed carbon feeding and in the presence of different initial concentrations of nitrogen].

The yeast Candida utilis IBPM-Y-405 was cultivated in a chemically defined medium in the conditions of pulse addition of a carbon source. The ultrastructure of the yeast cells was studied at different initial concentrations of a nitrogen source (0.152, 0.088 and 0.044 g of NH4+ per litre of the medium). Morphologically different mitochondria (dense and transparent) were found in one and the same cell at an initial concentration of NH4+ equal to 0.088 g per litre of the medium. When this concentration was equal to 0.044 g per litre of the medium, the number of transparent mitochondria increased, the mitochondria shrank, giant vacuoles comprising regions of the cytoplasm appeared in the cells, as well as large lipid inclusions, the cytoplasm became less thick and contained crystal-like inclusions. All of the aforementioned ultrastructural changes are quite reversible if the initial concentration of the nitrogen source is increased.

Candida↗
PubMedDate not supplied

[Ultrastructure of Candida utilis in continuous culture with various concentrations of the carbon source introduced by different technics].

The object of the work was to study changes in the ultrastructure of Candida utilis cells induced by increasing concentrations of glucose during chemostat cultivation and continuous cultivation with glucose pulse feeding. The results indicate that the cell structure and metabolism change vectorially with an increase of glucose concentration regardless of how glucose was added. An increase of the input glucose concentration is followed by an increase in the periplasmic space, the content of glycogen, the length and diameter of mitochondria, and the size of the nucleus. However, in the case of glucose pulse feeding, the above changes in the cell structure occur at a considerably lower input concentration as compared to the chemostat culture. Under these conditions, microtubuli are assembled in the cytoplasm in response to the glucose stimulus.

Candida↗
PubMedDate not supplied

[Effect of input nitrogen concentrations on Candida utilis growth in continuous culture with pulsed carbon feed].

The yeast Candida utilis IBPMY-405 was cultivated in a synthetic medium at a dilution rate of 0.05 h-1 in the regime of pulse glucose feed. The periodicity of glucose additions was determined by the current signal of an optical density sensor. Changes of the signal in the course of time were of a periodical character with the constant frequency and amplitude of fluctuations as long as the experimental conditions remained the same. Three concentrations of ammonium nitrogen were used (0.152, 0.064 and 0.043 g/l) to assay the number of cells in a unit volume of the culture, the percentage of budding cells, the quantity of nitrogen assimilated per cell, the consumption of oxygen, the increment of optical density in response to the addition of glucose (delta x) and the time taken by optical density to increase (tx). The parameters of phase I in the cycle of changes in optical density (tx and delta x) were found to depend on how the culture was supplied with nitrogen. As this supply decreased, tx increased and delta x decreased. The respiration rate and the percentage of budding cells underwent cyclic fluctuations while the overall quantity of cells per unit volume of the culture remained constant. An attempt has been made to substantiate the applicability of the parameters tx and delta x for testing the culture and rapidly identifying nitrogen limitation during continuous cultivation of Candida utilis in the regime of plus feed with source of carbon.

Candida↗