[The effect of exogenous antioxidants on the antioxidant status of erythrocytes and hepcidin content in blood of patients with disorders of iron metabolism regulation].

In many diseases associated with impairments in iron metabolism, erythrocytes exhibit an increased sensitivity to oxidative stress induced in vitro. In this study, we have examined the antioxidant status of erythrocytes from healthy donors and from 12 patients with disorders of iron homeostasis by measuring the extent of t-BHP-induced hemolysis in vitro. The extent of hemolysis observed with patient erythrocytes was significantly higher than that observed in experiment with normal cells.

[Effect of perftoran on morphology and rheologic properties of erythrocytes in patients with severe trauma and blood loss].

Erythrocyte morphology and function, plasma viscosity, central hemodynamics and oxygen status were studied in patients with severe injury and blood loss. The percentage of morphologically changed erythrocytes (mainly stomatocytes) increased, their filterability changed negligibly. Changes in these parameters were studied during intravenous infusion of perfluorane.

[Analysis of geometric parameters and mechanical properties of erythrocytes by filtration through nuclear membrane filters. II. Experimental verification of a mathematical model].

In the accompanying paper the process of erythrocyte passage through pores of membrane nuclear filters has been modelled. In order to test the model we have studied how the filtration rate of human erythrocyte suspension depends on osmoticity of the resuspending medium at various experimental conditions. We have tested and verified the model conclusion that the zero filtration rate is reached at the critical osmoticity value which depends only on geometrical parameters of the pore and the cell and not on other properties of the erythrocyte.

[Analysis of geometric parameters and mechanical properties of erythrocytes by filtration through nuclear membrane filters. I. A mathematical model].

A mathematical model is constructed, which quantitatively describes the rate of erythrocyte passage through pores of nuclear membrane filters during filtration of a diluted erythrocyte suspension upon action of a constant hydrostatic pressure. The following main factors have been taken into account: geometrical constraints linking the surface area of the erythrocyte membrane, the erythrocyte volume and the geometrical parameters of the filter pores; mechanical characteristics of the erythrocyte membrane; viscosity of the intracellular content. Analysis of the model allows us to conclude that it is possible to extract information about all above erythrocyte characteristics from the experimental curves describing, dependency of the filtration rate of the erythrocyte suspension from the osmoticity of the outer medium.

[A filtration study of erythrocyte deformability].

The study of two flow methods (constant flow method and initial flow rate method) has been conducted to specify and compare methodological approaches to quantitation of red cell deformability. Washed red cells were resuspended in saline medium with glucose and albumin and examined for deformability by the above methods under different conditions. The parameters are presented to characterize flow curves obtained with the constant flow method.

[Changes in the microviscosity of the plasma membrane and sensitivity to PGE1 of platelets stored at 22 and 4 degrees C].

Effect of platelet storage within 1-3 days on the cell membranes microviscosity, studied by means of a spin probe, and their sensitivity to PGEI, inhibitor of ADP aggregation, were studied. The highest values of fluidity and PGEI sensitivity exhibited plasmatic membranes of platelets stored at 22 degrees; lower values were found in the membranes stored at 4 degrees as compared with native fresh platelets. The data obtained suggest the dissimilar character of alterations in structure and functions of platelet plasmatic membrane during storage at 22 degrees and 4 degrees.

[Reversible inhibition of thrombocyte physiology by tetracycline derivatives].

Tetracycline and its derivatives (hydroxytetracycline and chlortetracycline) exert an inhibitory action, within a concentration range of 50-1000 microM on the basic functions of human platelets: aggregation, adhesion, retraction, hypotonic shock response, and release reaction. After resuspending and transfer of the inhibited platelets into plasma not containing tetracycline derivatives the functional activity of platelets partially or completely recovered. The evidence obtained suggests that the reversible inhibitory action of tetracycline results from its ability to easily penetrate the cell membranes and to bind intracellular calcium without substantial damage to the cells.

[Action of KCN on intact and refractory thrombocytes].

The effect of low KCN concentrations (5-10(4) M) on the ADP-induced aggregation of intact and refractory rabbit platelets was studied. KCN did not change the aggregation of the intact platelets, but stimulated that of the refractory platelets. The effect of the inhibitor stimulating the aggregation was not connected with the release of additional amounts of ADP.

[The existence of a thrombocyte refractory state].

The degree of ADP-induced platelet aggregation was considerably decreased during incubation of platelet-rich plasma with ADP. The data obtained showed that neither inhibitory action of the excess of adenosine, nor ADP breakdown in the plasma could account for this phenomenon. The results seem to indicate the significance of refractory state of platelets for the regulation of their aggregability.

[ATP concentration in thrombocytes at different stages of ontogenesis].

Intraplatelet ATP levels were measured in rabbits of different ages by the firefly technique. Adult and 7-8 day rabbits platelets proved to contain 8.9 +/- 0.

[A comparative study of the functional characteristics of thrombocytes at different stages of individual development].

A comparative study of ADP-induced aggregation was made in adult rabbits' intact and refractory platelets and in 7-day rabbits' platelets in vitro. Platelets of the young animals resembled refractory those of adults. The effect of ADP on platelets in vivo did not depend on the age of animals.