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Biomedical subjects

I A Ostapenko

Publications and source records attributed to I A Ostapenko.

26 records · Page 2Linked to original sources
PubMedDate not supplied

[Protein inhibitor of cyclic nucleotide phosphodiesterase in the retina in hereditary degeneration].

Thermostable protein fraction from retina of rats with hereditary retinal dystrophy (Hunter and Campbell strains) did not inhibit cyclic nucleotide phosphodiesterase. At the same time an inhibitory component, found in retina of Wistar rat, rabbit, frog and lamprey, was similar to the component from bovine retina. Quantity of the inhibitory component in normal rat retina decreased considerably within postnatal period (12 days--3 months). Thermostable proteins, isolated from Campbell rat retina, differed from that of Hunters' one by electrophoretic properties while both preparations were dissimilar to the protein of normal rat. Protein bands, containing inhibitory component from dystrophic rat retina, appear to be less distinct as compared to those of normal rat. These proteins, eluated from the bands of Campbell rats, activated phosphodiesterase but the preparations from Hunter rats did not influence on it.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMedDate not supplied

[Changes in the properties of photostimulated cyclic nucleotide phosphodiesterase from the retina of rats with hereditary retinal degeneration].

A degree of extractability and activation of cGMP-phosphodiesterase (PDE) (EC. 3.1.4.17) from the rod outer segment membranes was studied in Campbell rats with inherited retinal degeneration and control Wistar rats as compared to the control, the PDE extractability in the diseased rats was found to be considerably lower, which manifested as early as the 15th day of the postnatal life. Changes in the GTP-stimulated and basal PDE activity were observed in Campbell rats. Beginning from the 25th day of the postnatal life the GTP-stimulated PDE of degenerative retina decreased and by the 60th day it reached the basal activity level in these animals. In the diseased rats the first 57 days of postnatal life the basal activity of PDE was sufficiently higher, followed by a sharp decrease reaching the basal activity level of the control rats. The obtained data on the changed PDE activity are likely to be a result of the disturbance in the protein-lipid interaction and a change in the external layer of the photoreceptor membranes in rats with inherited retinal degeneration.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMedDate not supplied

[Changes in the activity of cyclic nucleotide phosphodiesterase and content of rhodopsin in retina during long illumination].

The phosphodiesterase activity in rat retina is found to decrease after a relatively short (1 h) and long (24 and 48 h) light exposition at 1200-1700 lx. illumination. The degree of decrease in the enzymic activity correlates with the exposure time. The rhodopsin capacity for regeneration is a criterion of the activity changes in the retina under the light effect. An hour illumination after the dark adaptation restores practically the initial level of the rhodopsin content and phosphodiesterase activity. A one- and two-day stay in the light causes a partial disturbance in the regeneration of rhodopsin and essential disturbances of the phosphodiesterase activity recovery in the retina.

3',5'-Cyclic-AMP Phosphodiesterases↗