[Ultrastructural and X-ray spectral analysis of cells U-937 during apoptosis process induced by hypertony].

The results of this work concerning ultrastructural changes of U-937 cells in a state of apoptosis are largely in consistent with the same information available in the literature. However, we have got the original data on the ultrastructural changes of cell organelles and immune localization and distribution of proteasomes. It has been demonstrated that Golgi apparatus is located close to the plasma membrane in the case of apoptosis induced by incubating the cells in a hypertonic suchrose solution (200-400 mM).

[Integration of monovalent ion fluxes across plasma membrane under the balanced state: ion gradients and water balance in animal cells].

Interrelationships between monovalent ion transport, the membrane potential, and intracellular ion and water content of an animal cell are analyzed by computation of the balance of ion fluxes across the plasma membrane when the sodium pump and electroconductive channels operate in parallel with NKCC or Na-Cl (NC) symport. The behavior of the system is described in terms of the integral permeability of Cl- channels, the activities of NKCC or NC symport and two dimensionless parameters characterizing the activity of the Na/K pump relative to that of electroconductive channels. The latter two parameters are shown to largely determine the plasma membrane potential and intracellular concentration of K+ and Na+ whereas NC and NKCC symports and the permeability of Cl- channels regulate cell water balance and only slightly influence the intracellular K+/Na+ ratio and membrane potential.

[Li/Na exchange and Li active transport in human lymphoid cells U937 cultured in lithium media].

Lithium transport across the cell membrane is interesting in the light of general cell physiology and becau- se of its alteration during numerous human diseases. The mechanism of Li4 transfer has been studied mainly in erythrocytes with a slow kinetics of ion exchange and therefore under the unbalanced ion distribution. Prolife- rating cultured cells with a rapid ion exchange have not been used practically in study of Li4 transport.

[Regulatory volume increase (RVI) and apoptotic volume decrease (AVD) in U937 cells placed into hyperosmotic medium].

Time course of changes in intracellular water, K+ and Na+ of U937 cells incubated in hyperosmolar medium with addition of 200 mM sucrose was studied. Ouabain-sensitive and ouabain-resistant Rb+ (K+) influxes were measured during regulatory cell volume increase (RVI) and apoptotic volume decrease (AVD). Microscopy of cells stained by Acrydine orange, Ethydium bromide, APOPercenrage Dye and polycaspase marker FLICA was performed.

[Computation of the K+, Na+ and Cl- fluxes through plasma membrane of animal cell with Na+/K+ pump, NKCC, NC cotransporters, and ionic channels with and without non-Goldman rectification in K+ channels. Norma and apoptosis].

The balance of K+, Na+ and Cl- fluxes through cell membrane with the Na+/K+ pump, ion channels and NKCC and NC cotransporters is considered. It is shown that all unidirectional K+, Na+ and Cl- fluxes through cell membrane, permeability coefficients of ion channels and membrane potential can be computed for balanced ion distribution between cell and the medium if K+, Na+ and Cl- concentration in cell water and three fluxes are known: total Cl- flux, total K+ influx and ouabain-inhibitable "pump" component of the K+ influx. Changes in the mortovalent ion balance in lymphoid cells U937 induced to apoptosis by 1 microM staurosporine are analyzed as an example.