Search

Intraocular liquid, in contrast to blood, has no cellular components; therefore, proteins (human serum albumin [HSA], and [alpha, beta, gamma] globulins) are the major components that determine patients' response to the intraocular lens (IOL) surface. In addition to the amount of adsorbed proteins, the possibility of its conformational changes, including conformational changes of globulins C1 and C3 that respond for the activation of the complements system by the classical and alternative pathways, cannot be excluded. The interaction between IOLs and protein components of intraocular liquid directly influences the ocular exudative reaction in the early postoperational period, the intensity of cellular and pigmental scurf on the surface of the IOLs, and the state of endothelial cells of the cornea in the distant postoperational period. Our goal was to compare the interaction of commercial IOLs made from polymethylmethacrylate, silicone, poly-2-hydroxyethyl methacrylate (p-HEMA), and copolymer p-HEMA with collagen with HSA and the complement system. The total internal reflection fluorescence (TIRF) method and hemolytic assay were used for this task, respectively. It has been demonstrated that the probability of biocompatibility of commercially produced IOLs on the stage of protein adsorption can be evaluated using the kinetic of HSA-fluorescein isothiocyanate adsorption onto the IOL surface by the TIRF METHOD: In the case of IOLs from p-HEMA, a negative correlation was shown between the degree of irreversible adsorption of HSA and the minimum relative rate constant of the surface-induced complement activation. We did not find any correlation between hydrophilicity/hydrophobicity of lenses and their adsorptional properties including complement activation. From suggested adsorptional criteria in vitro for biocompatible surfaces, the hydrogel lens from p-HEMA has a lower probability of biocompatibility in comparison with other IOLs.

The capacity of water-soluble polymers (polyethylenimine, polyvinylpyrrolidone with copolymers) to induce posterior detachment of the vitreous by its rapid condensation (vitreosynerysis) was studied in experiments on 14 rabbits. Histological studies showed that water-soluble polymers specifically react forming complexes with components of the vitreous. The vitreous shrinks under the effect of polyelectrolytes (vitreosynerysis), which leads to its posterior detachment 1.5 h after injection of the polymer into the vitreous cavity: complete detachment was attained in 2 animals and partial in 8. The degree of vitreosynerysis depends on the complex-forming activity of polyelectrolytes towards the vitreous components. Polymers used in our study exerted no toxic or traction effects on the adjacent structures of the eye.

The paper shows it possible to use the method of total internal reflection-fluorescence for study of the kinetics of protein adsorption onto the surface of intraocular lenses (IOL) made from optically transparent hydrophobic polymers and hydrogels. The nature of the materials (polymethylmethacrylate, silicone, p-HEMA, p-HEMA-collagen copolymer) used for IOL on the adsorption and desorption of human serum albumin was studied.

Reactions of heparin, covalently immobilized in hydrogel, with fibrinolysin, blood serum albumin, thrombin and fibrinogen were studied. All the proteins studied were shown to penetrate into the hydrogel pores and to interact with the immobilized heparin. Stability of the complexes was decreased in the following sequence: fibrinogen = thrombin much greater than fibrinolysin much greater than blood serum albumin. Complexes of the immobilized heparin with fibrinogen, thrombin and fibrinolysin hydrolyzed the unstabilized fibrin.

Sorbents for removal of proteases from biological fluids were synthesized via immobilization of a specific protease inhibitor-ovomucoid from whites of duck eggs--in the bulk of polymeric hydrogel. The sorbents were shown to exhibit high capacity and selectivity in the removal of proteases from the model protein-containing solutions, blood plasma and blood. The sorbents did not affect the blood cells as well as the blood-clotting system. The sorbents were demonstrated to be effective in the removal of proteases from canine blood in acute pancreatitis.

Covalent immobilization of the pancreatic trypsin inhibitor onto a polymeric carrier was accomplished by introducing a double C = C bond in the inhibitor with a subsequent copolymerization of the activized inhibitor with acrylamide and N,N'-methylenebisacrylamide. To prevent a loss of the antitryptic activity under acylation of lysine residues of the reactive centre, the inhibitor was preliminary bound to a complex with trypsin, which was destructed by acidifying the solution before copolymerization. The antitryptic activity of the immobilized inhibitor was shown to be equal to the activity of the inhibitor in the native state.