Is Episcleritis Associated to Glaucoma?

Objective: The aim of this study was to show possible connection between episcleritis and open-angle glaucoma.

Design: This was a retrospective study.

Materials And Methods: Data on 21 patients who suffered from episcleritis and had no previous attack of episcleritis or glaucoma were collected for a period of 8 years (from 2004 to 2011).

Managed ventricular pacing compared with conventional dual-chamber pacing for elective replacement in chronically paced patients: results of the Prefer for Elective Replacement Managed Ventricular Pacing randomized study.

Background: Several studies have shown that unnecessary right ventricular pacing has detrimental effects.

Objective: To evaluate whether minimization of ventricular pacing as compared with standard dual-chamber pacing (DDD) improves clinical outcomes in patients referred for pacemaker or implantable cardioverter-defibrillator (ICD) replacement.

Methods: In an international single-blind, multicenter, randomized controlled trial, we compared DDD with managed ventricular pacing (MVP), a pacing mode developed to minimize ventricular pacing by promoting intrinsic atrioventricular conduction.

[Quantitative determination and reversible modification of sulfhydryl groups in low and high molecular weight compounds using a biradical spin marker].

A new method for quantitation of sulfhydryl groups of low and high molecular weight compounds is proposed. The method is based on the use of a biradical spin label carrying a disulfide bond, RS-SR, where R is the imidazoline radical. It was found that this biradical is involved in the reaction of thiol-disulfide exchange with thiols; the EPR spectra of the original biradical and monoradical products differ essentially.

[Macromolecular spin pH-probes on the basis of human serum albumin].

Human serum albumin has been chemically modified by two different spin pH-sensitive labels of the imidazoline series containing in their structure alkylating and carboxyl groups, respectively. The ESR spectra of spin-labeled proteins are sensitive to pH of the medium. The pK values of spin-labeled proteins measured by the ESR method are: pKI = 3.

Determination of organic contaminants in residential indoor air using an adsorption-thermal desorption technique.

This field study evaluated the ability of a multi-sorbent sampling tube/thermal desorption technique to identify and to provide quantitative data on volatile organic contaminants in indoor air. Air samples, from 12 Canadian homes, were collected on multilayer sorbent cartridges and analyzed using Adsorption/Thermal Desorption coupled with Gas Chromatography/Mass Spectrometry. The study included the identification and quantitation of 23 target compounds.

[A study of the interaction of substrates with cytochrome P-450 by a method of UV- and 1H-NMR spectroscopy].

Acceleration of substrate longitudinal relaxation (T1) was used to study cytochrome P-450-aminopyrine (1st type substrate) and P-450-4-methoxypyridine (2nd type substrate) complexes. Dissociation constant, T1 and/or residence time of substrate in the complex can be obtained from the dependence of T1 of substrate protons on substrate concentration. Basing on the relaxation times, distances between Fe3+ ion in the active site and protons of the substrate moiety were determined.

[Affinity modification of membrane-bound microsomal cytochrome P-450 with lipophilic analogs of substrates].

The following lipophilic spin-labeled cytochrome P-450 analogs were synthesized: 2-octyl-4-(3-iodine-2-oxopropylidene)-2,3,5,5-tetramethylimidaz olidine-1-oxyl (RIII), 2-nonyl-4-(3-iodine-2-oxopropylidene)-2,3,5,5-tetramethylimidaz olidine-1-oxyl (RIV), 2-hepta-decyl-4-(3-iodine-2-oxopropylidene)-2,3,5,5-tetramethyl imidazolidine-1- oxyl (RV). The distribution coefficients, k, in water--lipid and water--octanol systems as well as the theoretical estimates of k for these and previously synthesized analogs, i.e.

[Penetration of ascorbic acid into bilayer phospholipid membranes].

Using the EPR method, the temperature dependencies of the rates of ascorbic acid-induced reduction of nitroxyl radicals carrying the nitroxyl fragment in different positions of the fatty acid chain [N(4-methylidene++-1-oxyl-2,2,5,5-tetramethyl-3-imidazolidine hydrazine)]myristic acid (I) and 1-oxyl-2,2-dimethyloxazolidine derivatives of 5-ketostearic (II) and 12-ketostearic (III) acids incorporated into egg phosphatidylcholine liposomal membranes were studied. The reduction rates, activation energy and shape of kinetic curves were found to be dependent on the mode of liposome preparation (ultrasonication or reverse phase evaporation), label type and chemical composition of the membrane (with regard to the presence or absence of stearic acid). The coefficients of partition and diffusion of ascorbic acid through the membrane lipid bilayer were calculated from the rates of transbilayer (flip-flop) diffusion of I and ascorbate penetration inside the liposomes containing Fremi salt nitroxyl radical.

[The study of the structure of active center of membrane-bound cytochrome p-450 using 1-naphthoxyalcanthiols].

Homologous 1-naphtoxyalcanthiols of the type 1-C10H7O(CH2)nSH (n = 2-7) are used for structural studies of the microsomal cytochrome P450 active centre. It was found that the strongest complex of thiol with P450 is formed for n = 3. Microsomal oxidation of P450 substrates aminopyrine and benz(a) pyrene is inhibited by the 1-naphtoxyalcanthiols studied.

[Substrate reduction and oxygen activation during microsomal metabolism of quinones].

2-Dimethylamino-3-chloro-1,4-naphthaquinone (DCNQ) was used to study oxygen and substrate activation in microsomal system. DCNQ was shown to be bound to microsomal cytochrome P-450 as a type I substrate; its N-demethylation was catalyzed by cytochrome P-450. Cytochrome P-450 and NADPH-cytochrome P-450 reductase are capable of DCNQ reduction to semi- and hydroquinones.

[Effect of the lipophilic spin-labeled inhibitor of cytochrome P-450 on the activity of the microsomal system].

It was shown that the lipophilic nitroxyl radical--2-hexyl-2,3,5,5-tetramethyl-4-(3-iodo-2-oxopropyliden)-im idazolidine- 1-oxyl, an affinity modified of rat liver microsomal cytochrome P-450, interacts with various forms of cytochrome P-450 as substrate type I, and it inhibits the oxidation of substrates specific for these forms. During its intravenous injection with egg phosphatidylcholine liposomes the radical is partly bound to liver microsomes, which is accompanied by a decrease of the oxygenase activity of microsomal preparations (by 30-50%) as well as by prolongation of the soporific effect of hexabarbital (2-3-fold).

[Inhibition of enzymes of insecticide detoxication in insects by an alkylating analog of a cytochrome P-450 substrate].

It was shown that the alkylating analog of cytochrome P-450 substrate - 4-bromomethyl-2,2,5,5-tetramethyl-3-imidazoline-3-oxide-1-oxyl effectively inhibits in vitro the activities of monooxygenases, glutathione-S-transferases and esterases from the abdomen of the house fly Musca domestica L. The non-alkylating analog (RH) appeared to be a very weak inhibitor of these enzymes. It was demonstrated that the inhibitory action of the alkylating analog consists in its covalent binding to the enzyme protein.

[Use of spin-labelled substrate analogs for a comparative study of microsomal cytochrome P-450 and P-448].

The previously described, iodine-labeled alkylating stable nitroxyl radicals located at different distances between the N-O. group and the iodine atom were used for a comparative study of the structure of microsomal cytochromes P-450 and P-448 active centers. The radicals were shown to change the optical spectra of Fe3+ located in the active site of the enzyme that are similar to those induced by cytochrome P-450 substrates.

[Interactions of microsomal cytochrome P-450 with spin-labeled substrate analogs].

The iodine-containing stable iminoxyl radicals with various distances between the N-O-group and the iodine atom are proposed to be used to study the structure of the active center of the microsomal cytochrome P-450. The radicals used induce changes in the optical spectra of the Fe3+ ion located in the active center of the enzyme, as in the case of type 1 substrates and inhibit essentially the microsomal oxidation of cytochrome P-450 substrates of type 1 and 2. This inhibition is neither due to suppression of the NADPH-cytochrome c reductase activity nor to cytochrome P-450 conversion to cytochrome P-420.

[Interaction of RNA polymerase of Escherichia coli with substrate by affinity labeling and NMR with nuclear 31P].

The affinity labeling of E. coli RNA polymerase by periodate oxidized uridine triphosphate was carried out without and with the template (polydeoxynucleotides poly(dA) and poly(dT) ), and under the conditions of poly(dA) and poly(dT) transcription. The extent of RNA polymerase labeling was nearly the same in the presence of poly(dA) and poly(dT) (0.

[Interaction of the Cu(Lys)2 complex with the NADPH-dependent microsomal electron transport system and microsomal membrane].

The low molecular weight analog of superoxide dismutase, th Cu(Lys)2 complex inhibits the oxidation of type I (piperidinoanthraquinone) and type II(aniline) substrates catalyzed by cytochrome P-450. This fact is not associated with the conversion of cytochrome P-450 into the inactive form--cytochrome P-420. It was shown that the method of determining the activity of NADPH-cytochrome c-reductase by the cytochrome c reduction rate cannot be employed in the presence of the Cu(Lys)2 and Cu(Tyr)2 complexes.

[Anomalous surface conductivity of phospholipid membranes].

Surface conductivity (SC) of the double layer at the phospholipid liposome surface has been examined with quasi-elastic light scattering technique combined with pulse electrophoresis. 23Na NMR was used to study the interaction between sodium ions and liposomes. The migration of bound ions along the surface was shown to produce the main contribution to SC.

[Cytochrome P-450 catalyzed oxidation of 1-piperidinoanthraquinone].

Oxidation of 1-piperidinoantraquinone (1-PA) in microsomal fractions of rat liver was studied. The only product of complete oxidation of 1-PA--(N-antraquinone-1)-delta-aminovaleric acid-was identified using paper and thin-layer chromatography. The participation of cytochrome P-450 in oxidation of 1-PA was demonstrated by sharp inhibition, involving blowing of the microsomes with CO and treatment with sodium deoxycholate.

[Effect of a magnetic field on the rate of H202 breakdown by catalase and by an Fe3+--EDTA complex].

The acceleration of H202 decomposition induced by catalase and the dimer complex [Fe3+(EDTA)]2 has been observed in a constant magnetic field. The effect increases with the field increasing up to 8000 Oe, reaching 20 +/- 5% and 24 +/- 5% for catalase and [Fe3+(EDTA)]2 respectively. The results are discussed within the hypothesis of a one-electron reaction mechanism using the models developed specially to explain the magnetic effects in radical reactions.