The structural transitions of erythrocyte membranes induced by cyclic AMP.

The generalized structural transitions of erythrocyte membranes induced by cyclic AMP were registered by ESR, fluorescence, freeze-fracture and circular dichroism methods. Two transitions different in nature were revealed. One, which arises at 10-(11)--10-(10) M cyclic AMP, is cooperative and may be considered as a consequence of interaction of cyclic AMP with a receptor. It was calculated that a structural rearrangement in one erythrocyte ghost is induced by three cyclic AMP molecules. As a result of it the membranes are "loosened". The other transition arises at 10-(10)--10-(8) M cyclic AMP and depends on the activity of the protein kinase system. This transition was shown to be non-cooperative and due to phosphorylation of membranous proteins. During this rearrangement the membranes are "stiffened". Both transitions were demonstrated to relate to the membrane integrity.

[Effect of cAMP on the structural and functional properties of the erythrocytes]. / Vliianiie tsAMF na strukturno-funktsional'nye svoistva éritrotsitov.

Cyclic AMP inhibits the anion transport and decreases the osmotic resistance and deformability of erythrocytes with the normal level of ATP. With ATP-depleted erythrocytes cAMP exerted the opposite effects on the corresponding characteristics. In addition, it was observed that the pattern of cAMP effect on the cell form depends on the basal level of ATP. These effects may be associated with the two types of structural rearrangements of erythrocyte membranes established earlier: a cooperative transition not connected with protein kinase system, and a non-cooperative one caused by protein phosphorilation.

[Effect of the critical fragmentation of erythrocyte membranes]. / Effekt kriticheskoi fragmentatsii éritrotsitarnykh membran.

After sonification of erythrocyte membranes, some changes were registered in these including a loss of their ability to structural rearrangements caused by cAMP (ESR-spectroscopy and luminescence data), an increase in cAMP binding and aggregation of intramembrane particles (freeze-fracture data). These findings suggest a non-identity of the structural organization in membranes and in their fragments. The cooperative nature of membrane structural modification at ultrasonic fragmentation is shown.

[Changes in the lipid physical state in human erythrocyte membranes subjected lead exposure in vitro]. / Izmenenie fizicheskogo sostoianiia lipidov v éritrotsitarnykh membranakh cheloveka pri deistvii svintsa in vitro.

The effect of lead acetate on the physical state of membrane lipids in human erythrocytes in vitro was studied using the lipophilic fluorescence probe 1,6-diphenyl-1,3,5-hexatriene and spin probes 16-doxyl-stearate and iminoxyl palmitic acid. It was shown that 2-10 microM lead acetate causes an increase in both intensity and polarization of fluorescence of 1,6-diphenyl-1,3,5-hexatriene, indicating changes in the microviscosity of the lipid bilayer of erythrocyte membranes. Judging from the parameters of EPR spectra of 16-doxyl stearate and iminoxyl palmitic acid incorporated into erythrocyte membranes, 2-10 microM lead acetate increases the heterogeneity of the lipid bilayer in surface and deep hydrophobic layers of the erythrocyte membrane.

[Role of acetylcholinesterase in the transmembrane transfer of anions in erythrocytes]. / Rol' atsetilkholinésterazy v transmembrannom perenose anionov v éritrotsite.

Data are presented in favour of the regulatory role of AChE in passive transmembrane transfer of anions: 1) gradual inhibition of the enzyme with proserin brings about the change of the transport activation energy and irregular shift of temperature in the salient point on Arrhenius curves; 2) complexing of different AChE inhibitors (succinyl cholinechlorine, tetraethyl ammonium, tetramethyl ammonium, d-tubocurarin, proserin) results in the change of transport velocity. A significant increase of membrane binding of highly efficient and specific inhibitor of SITS anion transport forming complexes with membrane transport sites under the effect of acetylcholine AChE substrate is recorded. Proserin acts in the same direction, but to a much lesser degree. The removal of acetylcholine effect which activates SITS binding with the AChE inhibitor points to the initiation of structural disturbances from this enzyme. The scheme of AChE regulatory effect is suggested: modification of the enzyme conformation at the interaction with the inhibitors or substrate--structural rearrangement of the membranes--modulation of anion channels.

[The use of laser irradiation in nephrological practice]. / Primenenie lazernogo oblucheniia v nefrologicheskoi praktike.

The authors studied therapeutic potential and mechanism of action of low-intensity low-energy laser irradiating the skin at the site of the projection of the transplanted kidney poles through the development of chronic rejection or chronic pyelonephritis. The trial included 7 kidney recipients and 9 controls with primary chronic pyelonephritis. The treatment course implied 10 daily session of 20 minutes duration of He-Ne laser irradiation which was preceded by clinical-laboratory evaluation of the blood and urine, cellular and humoral immunity, hemostasis, central hemodynamics, local and mediator hormones, factors of nonspecific resistance, spin probe characteristics. The effect appeared contradictory. It is thought valid to combine quantum and drug therapy thus achieving optimal therapeutic effects and preventing side effects.