[Activation of bovine retinal rod outer segment cGMP-specific phosphodiesterase by the transducin-GTP complex in a physiologically significant range of free calcium ion concentrations].

The kinetic behavior of cGMP-specific phosphodiesterase in a totally bleached bovine retinal rod outer segment suspension was studied by the pH-metric method at high and low concentrations of free calcium ions (≈ 100 μM and 10 nM, respectively). The phosphodiesterase was activated by low GTP concentrations (about 1-2 μM) that were comparable with the concentration of G-protein transducin, its GTP-binding alpha-subunit was the intrinsic activator of photoreceptor phosphodiesterase. The results allow the suggestion that besides the earlier described system of RGS proteins, participating in the acceleration of GTP hydrolysis, rod outer segments also contain an additional Ca(2+)-dependent mechanism to inactivate so called "free transducin", i.

[The phosphorylation state of transducin beta-subunits].

The supposition that nucleoside diphosphate kinase is the enzyme that phosphorylates transducin beta-subunits on one of the histidine residues (His-266) has been analyzed. It stands the reason that 1) this enzyme is multifunctional and plays in particular the role of protein histidine kinase; and 2) the phosphorylated beta-subunit of transducin may activate transducin via the mechanism of transphosphorylation. Nevertheless, in our experiments, in which different forms of transducin preparations were incubated with α- and β-isoforms of recombinant rat NDP kinase in the presence of [γ32P]ATP or [γ32P]GTP (specific activity of about 1 Ci/mmol) followed by separation of proteins by electrophoresis and-gel radio-autography, the phosphorylation of the transducin beta-subunit wasn't succeeded to be found.

Solid-phase extraction on alkyl-bonded silica gels in inorganic analysis.

Solid-phase extraction (SPE) is an effective tool for the preconcentration of trace elements and their separation from various sample constituents. Octadecyl and other alkyl-bonded silica gels are most widely used for these purposes. The fundamentals of the SPE of inorganic ions are reviewed and compared with those of related techniques (liquid-liquid extraction and reversed-phase liquid chromatography).

Quantitative structure-mobility relationship modelling of electrokinetic chromatography of metal complexes: approaches and limitations.

A charged surfactant or an ionic polymer added to the capillary electrolyte introduces micellar solubilization and ion-exchange interactions, respectively, as a supplementary separation principle for metal complexes among a great many other analytes. Acting as a pseudostationary phase, such electrolyte additives make the separation mechanism fairly different from that based only on differences in electrophoretic mobility. A range of quantitative structure-mobility relationships were developed to explain the migration behavior of metal complexes in micellar and ion-exchange electrokinetic chromatographic systems as a function of their primary structural parameters.

Migration behavior of metal complexes in capillary zone electrophoresis. Interpretation in terms of quantitative structure-mobility relationships.

Significant advances in metal ion analysis by capillary zone electrophoresis (CZE) have occurred as a consequence of using metal complexes with various organic and inorganic ligands. Metal-ligand complexes that contribute to metal speciation in solution have also gained the attention of researchers. An understanding of the molecular properties that control the separation and further insight into the migration mechanism call for a systematic analysis of relationships between migration parameters and charge and size characteristics of metal complexes.

[The role of polyene fatty acids in the development of acute inflammation in rats].

The effect of n6 and n3 polyunsaturated fatty acids (PUFA) on development of acute inflammation in rats has been studied. During 4 weeks male Wistar rats (initial weight 140-150 g) were on feed containing as lipid component 6% butter and 3% fish oil obtained from Sardinops sagax melanosticta (n3 PUFA-diet). The development of paw oedema induced by subplantar injection of dextran or carrageenan inhibited when the animals were on diet where prevailed n3 PUFA.

High-performance liquid chromatography of metal chelates: Environmental and industrial trace metal control.

The methodological aspects of the use of HPLC in determination of metals in the form of their chelates are discussed. Rational schemes for the analysis of complex environmental and industrial samples are presented, including choice of chelating reagent, chelate preparation, metal concentration, separation method and detection method. Examples of the application of HPLC of metal chelates to environmental, production and quality control are presented.

Ion-selective electrodes for gold and silver determination.

Some new ion-selective electrodes for silver and gold are described. They are based on the ion-associate species formed by the cyanide, chloride or thiourea complexes of the metals, with hydrophobic anions or cations, as appropriate. The electrodes have been applied to the determination of gold and silver in various technological process solutions in industry.

[Radiotherapy and combined chemo- and radiotherapy of patients with squamous cell lung cancer (randomized study)].

A randomized study on the results of treatment of 76 cases of squamous cell carcinoma of the lung was conducted at the Center in 1976-1981. Radiation and chemoradiation procedures were studied in two groups of patients. The immediate results of chemoradiation therapy were somewhat better as compared with radiation treatment alone.