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Biomedical subjects

A K Gulevskiĭ

Publications and source records attributed to A K Gulevskiĭ.

At least 19 recordsLinked to original sources
PubMed2006

[Low-molecular peptides from tissues of hibernating and cold-adapted animals influence cell proliferation in the Ehrlich ascitic carcinoma].

Polypeptides with cytostatic activity are known to be present in animal tissues during winter dormancy. A 1-10 kDa polypeptide fraction with cytostatic activity was obtained from brain tissue of hibernating ground squirrels and cold-adapted Yakut horses. The pattern of cytostatic activity of this fraction towards tumor cells is of great interest. We present results testifying to cytostatic activity of this fraction towards the Ehrlich ascitic carcinoma cells. The cytostatic effect is realized in tumor cells at the genetic level.

Adaptation, Physiological↗
PubMed1992

[Effects of the fraction (1-10 kDa) of the brain of a Yakut horse on kinetic parameters of Ca2+ transport system in sarcolemma vesicles of cardiomyocytes].

The effect of the fraction (1-10 kDa) obtained from the brain of cold-adapted animal (Yakut horse) on Ca2+ transport in sarcolemma vesicles of cardiomyocytes was investigated. It was shown that during insertion of Yakut horse brain fraction into incubation medium at the concentration from 10(-9) M to 3.10(-5) M at Ca2+ transport substrate concentration from 0.1 mM to 1.0 mM, the rate of Ca2+ passive penetration into vesicles slightly increased and at Ca2+ transport substrate concentration 3 mM, which is physiologic, a decrease of rate values was established for all concentrations of the fraction (1-10 kDa) of Yakut horse. While studying the kinetics of an active Ca2+ transport for all investigated concentrations of the fraction (1-10 kDa) of Yakut horse brain from 10(-9) M to 3.10(-5) M at Ca2+ concentration in incubation medium from 10(-7) to 3.10(-6) M, calcium accumulation rates by vesicles exceeded control values. So we can suppose that application of brain fraction (1-10 kDa) of genotypically cold-adapted animal, results in a decrease of intracellular Ca2+ concentration.

Adaptation, Physiological↗
PubMed1991

[Total protein and RNA biosynthesis in the liver cells of the long-tailed suslik Citellus undulatus in different functional states].

The synthesis of proteins and RNA have been studied by means of labeled precursors of 14C-amino acids and 14C-orotic acid in liver cells of hibernating, arousing and active ground squirrels (Citellus undulatus). The investigations conducted testify to the possibility of CHI-inhibited synthesis of proteins in liver cells of hibernating ground squirrels, which occurs, apparently, on preexisting polyribosomes. The low level of protein biosynthesis in this state is stipulated not only by the Arrhenius dependence, but by the dissociation of polyribosomes into monosomes as well. In the course of arousal, an intensive assembling of polyribosomes was detected even under the inhibition of RNA synthesis by actinomycin D, testifying to the presence of a pool of mRNA [correction of iRNA] in liver cells, which are necessary for the observed activation of translation. The intensity of protein synthesis on arousal is also stimulated by the activation of transcription.

Animals↗
PubMed1990

[Structural reorganizations of the lipids and proteins of erythrocyte membranes under the action of low temperatures].

The reversible structural rearrangement of lipids and protein oligomerization has been shown to occur during cooling in membranes of model systems (liposome, erythrocyte shadows) and native erythrocytes. Analysing the dependence of Azz in membrane probes (5- or 15-doxylstearic acids) in the Arrhenius plots a conclusion on the structural changes at 13-19 degrees C and within the range of interior water freezing from -17 up to -19 degrees C has been drawn, the last transition is smoothed out in the presence of glycerin. Using diamide joining spectrin and electrophoresis in polyacrylamide gel it has been determined that the low temperatures cause the spatial approach of proteins of spectrin-actinic complex and formation connections between the erythrocyte membrane proteins which aren't destroyed by dodecylsulfate.

Cold Temperature↗
PubMed1986

[Structural changes in erythrocyte membranes during cooling studied by a spin probe method].

Peculiarities of structural changes in erythrocyte membranes during freezing (from -20 degrees to -50 degrees) were studied by electron paramagnetic resonance method using spin-labelled derivative of stearic acid-5-doxylstearate. It was established that membranes underwent a number of structural reconstructions due to the temperature decrease and water freezing-out. Differences were found in temperature dependences that characterize lipid ordering during probe insertion into membranes of native erythrocytes, white ghosts, and liposomes from total lipids of erythrocyte membranes. The data obtained indicate the impairment in the structure of lipid components and lipid-protein interactions in erythrocyte membranes during cooling.

Cold Temperature↗
PubMed1983

[Biochemical indices of erythrocytes cryopreserved with protection by 1,2-propanediol and glycerin].

Based on the data concerning the content of ATP, 2,3-DFG, K+, and Na+ in depreserved red cells stored at 4 degrees C in resuspending media TsNIIGPK 8b and 8v it has been established that blood preserved under protection of 1,2-propanediol is comparable with that preserved under glycerin protection as regards its quality and is even better from the standpoint of some other indicators. Medium TsNIIGPK 8v may be used as resuspending medium for blood exposed to low temperature preservation under protection of 1,2-propanediol.

Adenosine Triphosphate↗
PubMed1981

[Effect of low temperature exposure on the membrane permeability of erythrocytes reconstructed in media of different ionic strength].

A study was made of the egress of hemoglobin, 14C-saccharose, Na+ and K+ from red blood cells reconstituted in media of varying ionic composition and exposed to rapid freezing and thawing. The reconstitution of red blood cells in a medium containing Na+ (150 mM) and Mg2+ (4 mM) favours their resistance to rapid freezing and thawing that is confirmed by the data on their permeability by hemoglobin, 14C-saccharose and cations. Red blood cells reconstituted in KCl (150 mM) combined with Mg2+ (4 mM) or Ca3+ (50 mcM) are cryolabile. The increased cryoresistance of the reconstituted red blood cells in the presence of Na+ is of nonspecific nature and mostly related to the effect on the inner surface of the plasmatic membrane. Impairment of the permeability of the reconstituted red blood cells correlates with the diminished cellular volume after freezing and thawing.

Blood Preservation↗
PubMed1981

[Role of lysosome permeability disorders in the mechanism of the low-temperature inhibition of protein biosynthesis in the rat liver].

The effect of the supernatants of lysosomes subjected to a rapid or slow freezing and thawing on the protein-synthesizing activity of the rat liver postmitochondrial supernatant (S15) has been studied. It has been found that the addition of supernatants obtained after a slow freezing or thawing to a cell-free system results in a significant inhibition of 14C-leucine incorporation that is in a good agreement with their RNase activity. However, the RNase activity of lysosomal supernatants or Triton-lysate appears to be higher that the inhibitory effect on protein biosynthesis. The damaging effect of supernatants obtained after 2-hour storage at 2-4 degrees C of the frozen-thawed lysosomes has not virtually changed.

Animals↗
PubMedDate not supplied

[Antioxidant system in the darkling beetle (Tenebrio molitor) in ontogenesis].

The level of antioxidant protection and lipid peroxidation (LP) intensity in the darkling beetle Tenebrio molitor on different developmental stages were assessed. Each stage was shown to be characterized by its own peculiarities of prooxidant-antioxidant balance. Thus, maximal intensity of oxidative processes estimated by LP intermediate product (diene conjugates and ketodiens) accumulation is attributable to pupae, and minimal intensity--to the 3rd-5th instar larvae. Superoxide dismutase activity increases gradually during the life cycle. A decline in catalase (CAT) and glutathione reductase (GR) activities occurred on the stage of pupae. CAT activity in imago was equal to the larva values, and GR activity in imago even exceeded the larva values. At the same time GR activity in T. molitor was detected only at 37 degrees C under our experimental conditions. No statistically significant changes in glutathione reduced content were observed in the insects during the life cycle.

Animals↗
PubMedDate not supplied

[The characteristics of the structural-functional state of the erythrocytes from homoiothermic and heterothermic animals during hypothermic storage].

Haemoglobin leakage and permeability for 86Rb and K ions during storage at normal and hypothermic conditions have been investigated in the erythrocytes of the ground squirrel Citellus undulatus in hibernating, arousing and awake animals, as well as in rats. During hibernation, stabilization of the barrier properties and a decrease in passive ionic permeability of erythrocyte membrane were observed. Preservation of ionic homeostasis of the erythrocytes in hibernating animals is favoured by activation of Na(+)-pump. By means of radioautography of electrophoregrams of the blood serum proteins, appearance of a rapidly labeling low-molecular protein was noted at the beginning of the baut and its disappearance before arousal. The data obtained are discussed in relation to the role of the blood plasma components in modification of erythrocyte membranes in hibernating animals.

Animals↗
PubMedDate not supplied

[Protein synthesis in the organs of the long-tailed suslik (Citellus undulatus) in various functional states].

Protein synthesis has been observed in brain and liver of susliks during hibernation using specific radioactivity assay and cycloheximide inhibitor analysis. The data on cycloheximide sensitivity and radioactivity of total protein fractions after differential centrifugation suggest that protein synthesis during hibernation is mostly carried out on microsomes. Experiments on protein synthesis in cell-free extracts from liver of suslik at various functional states indicated that the pool of polyribosomes during hibernation is similar to that during wakening period and waking state. This may ensure high intensity of protein biosynthesis at increase in body temperature during wakening.

Amino Acids↗
PubMedDate not supplied

[The effect of diphylic compounds on the transport of metabolites and cations in eukaryotic cells].

The effect of DMSO, glycerol, PEG, PVP on passive and active transport of metabolites and cations to the cells of Ehrlich ascites carcinoma and erythrocytes has been investigated. The data indicating the stimulation or reversible inhibition of amino acid, nucleosides transport dependent on concentration of diphylic compounds have been shown. The inhibitory mechanisms of processes of metabolite and cation transport have been discussed.

Animals↗
PubMedDate not supplied

[Effect of moderately low temperatures (-30 C to -70 C) on the permeability of erythrocyte membranes].

The barrier properties of reconstituted and native erythrocyte membranes frozen to -30, -40 or -70 degrees C and stored for a month were studied. The release of markers, namely haemoglobin molecules, [14C] sucrose and K+ ions from cells and membrane structures was measured. The main changes in the barrier function of ghosts and cells have been found to be due to freeze-thawing rather than to storage conditions. Glycerol, a cryoprotectant, appeared to stabilize the barrier properties of erythrocyte membranes for haemoglobin molecules, [14C] sucrose and to a lesser extent for K+ ions. The cryoprotective effect of glycerol has been shown to be considerably greater towards erythrocytes ghosts than to native erythrocytes.

Blood Preservation↗
PubMedDate not supplied

[Effectiveness of the cryoprotective effect of glycerol and polyethylene glycol on plasma membranes].

The barrier properties of erythrocyte membranes were studied under freezing-thawing in cryopreservatives based on glycerol or polyethylene glycol Mm 1500 Da (PEG-1500) (at cryoprotectant concentrations from 0.5 to 30%). The state of the membrane barrier function in reconstituted and native erythrocytes subjected to rapid (200-400 degrees C per min) freezing has been registered by spectrophotometry, flame photometry, and radiolabel analysis as judged by labeled compound release (hemoglobin, K+, [14C]sucrose, 86Rb+). It is demonstrated that the effective cryoprotection of erythrocyte membranes in reconstituted erythrocytes is attained at cryoprotectant concentrations in the medium of 0.5-1% or in erythrocytes of 8-30%.

Blood Preservation↗