[Fluorescence polarization immunoassay of ractopamine].

A technique was developed for fluorescence polarization immunoassay (FPIA) of ractopamine, a toxic low molecular weight nonsteroidal growth regulator belonging to the most controlled contaminants of food products of animal origin. The assay is based on the competition between a sample containing ractopamine and ractopamine–fluorophore conjugate for binding to antibodies. The competition is monitored via changes in the degree of fluorescence polarization for plane-polarized excitation light, which differs for the free and antibody-bound forms of the conjugate.

[COMPARATIVE STUDY OF MECHANICAL STRESS EFFECT ON HUMAN AND ANIMAL ERYTHROCYTES].

Sensitivity of human and animal (bovine, rat, rabbit, equine) erythrocytes to the effect of mechanical stress has been studied. Mechanical stress effect was demonstrated to result in a time-dependent (5-60 min) release of potassium cations out of mammalian erythrocytes and a partial hemolytic cell damage. Herewith the release levels of potassium ions and hemolysis did not coincide for erythrocytes of all the mammals except rabbit ones.

[Effect of C60 fullerene on viscoelastic properties of human erythrocytes membrane].

The effect of C60 fullerene aqueous colloid solution (C60FAS) on viscoelastic properties of human erythrocytes membrane has been studied. It was established that the effect of C60FAS on erythrocytes depends on the medium osmolality and concentration of C60 fullerene in it. In particular, in isotonic solution (0,15 mol/l NaCl) adding C60 fullerene in concentrations from 0,7 to 28 μmol/l did not cause the hemolytic damage of cells.

[Effect of cationic and anionic amphiphilic compounds on hypertonic cryohemolysis of mammalian red blood cells].

We studied the effect of derivatives of anionic (sodium decyl- and dodecyl- sulphate) and cationic (trifluoperazine, chlorpromazine) amphiphilic compounds on morphological peculiarities and hypertonic cryohemolysis of human, rabbit, bovine, equine red blood cells. The mentioned substances cause changes in red blood cell shape for all the studied mammals: anionic amphiphils on the discocyte-echinocyte type and cationic ones on discocyte-stomatocyte type. It was revealed a significant antihemolytic activity of the studied substances under hypertonic cryohemolysis of mammalian red blood cells with manifested species differences in the efficiency.

[Mechanism of protective effect of amphiphilic compounds during hypertonic hemolysis of erythrocytes].

Antihemolytic effect of various amphiphilic compounds under conditions of red blood cell hypertonic hemolysis at different temperatures (0 and 37 degrees C) and cell exposure to diamide was investigated. The level of maximum antihemolytic activity and values of efficient concentrations for all studied substances were lower at 0 degrees C if compared with 37 degrees C. Exposure of erythrocytes to diamide (5 and 10 mmol/l) did not change cell sensibility to hypertonic medium.

Effect of alkyl-beta,d-glucopyranosides on hypertonic haemolysis of erythrocytes.

The effect of temperature (5-20 degrees C) and treatment with phenylhydrazine on the hypertonic lysis of erythrocytes in the presence of alkyl-beta,d-glucopyranosides was studied. The results highlight an important role for the cytoskeleton-membrane complex, which allows the cells to both withstand hypertonic stress within the temperature range studied and facilitate the protective effect of alkylglucopyranosides at low temperatures (5 degrees C).

[Protecting effect of trifluoroperazine during hyperosmotic erythrocyte shock].

It has been shown that antihemolytic effect of trifluoroperazine is realized directly at the stage of hyperosmotic stress during cell transfer to 4.0 M NaCl and is not the result of preliminary cell treatment by this amphypathic compound. The value of protecting effect of trifluoroperazine is determined by preliminary RBS dehydration condition.

[Antihemolytic effect of chlorpromazine on erythrocytes in hyperosmotic and cold shock].

The combined effect of preliminary dehydration of erythrocytes and the cationic amphiphilic compound, chlorpromazine, on the stability of cells to subsequent hyperosmotic effect, has been studied. A protective effect of chlorpromazine depending on the degree of initial cell dehydration and temperature was found. The results obtained by an addition of the cationic amphiphile at preliminary stages of the experiment and directly in the process of development of hyperosmotic lysis have been compared.

[Sensitivity of chlorpromazine-modified eryhtrocytes to cold stress].

Development peculiarities of hypertonic cold shock of erythrocytes modified with chlorpromazine were studied, maximum protection effect under cooling of cells is registered when using chlorpromazine in the concentration 7 x 10(-5) M. Spectrin denaturation does not change general pattern of the effect of different concentrations of amphipat on sensitivity of erythrocytes to the cold shock but it sensitizes cells modified by chlorpromazine (7 x 10(-5) M) to the further cooling. Differences between native cells and erythrocytes with denatured spectrin are levelled at higher concentrations of amphypat, certain protective effect being observed at certain values of the medium tonicity.

[The effect of chlorpromazine on the temperature and osmotic sensitivity of erythrocytes].

The effect of chlorpromazine on the development of cold shock in erythrocytes exposed to sodium chloride was shown to depend on the tonicity of the medium in which the cells were cooled from 37 degrees C down to 0 degrees C as well as on the amphipate concentration. After cooling of erythrocytes in a NaCl (0.75-1.

[Mechanism of erythrocyte cryohemolysis, induced by cationic amphipaths: synergism of induction of the "discocyte-stomatocyte III" transition due to chlorpromazine and medium tonicity].

It is determined that chlorpromazine, a cationic amphipath usually protecting erythrocytes under conditions of hypertonic cryohemolysis is an efficient inductor of the cell lysis in case of cooling in media with tonicity close to the physiological (the isotonic cryohemolysis). Both chlorpromazine and tonicity of the medium influence the alterations in the state of cells, which is confirmed by synergy of the "discocyte-stomatocyte III" transition induction. The above process may be considered as a critical stage of structural modification of erythrocytes.

[Modifying effect of concanavalin A and diamide on erythrocyte sensitivity to cold shock].

The temperature (0 degrees C and 37 degrees C) and the medium tonicity (0.15-1.20 M NaCl) were shown to affect erythrocyte agglutination by concanavalin A.