[Antioxidant system activities and lipid peroxidation in nodal and non-nodal thyroid tissue of patients operated in connection with euthyroid nodular goiter].

The activities of the antioxidant systems (AOS) and lipid peroxidation (LP) were studied in the thyroid (operation material) of patients with euthyroid nodular goiter (in carcinoma, adenoma, colloid goiter tissues as well as in non-nodular adjacent thyroid tissue). Increased activities of superoxide dismutase (SOD, by 101.0 and 125.9%), catalase (by 76.6 and 71.2%), glutathione peroxidase (by 109.6 and 249.2%), glutathione reductase (by 84.6 and 195.9%) and LP aldehyde products (by 148.5 and 120.4%) were found in the adenoma and carcinoma tissues. The increased antioxidant system activity (SOD by 1.62-fold) and LP level by 1.62-1.65--fold in the non-goiter adjacent tissue from these patients indicate toxicity of malignant and non-malignant tumors for the adjacent normal thyroid tissues. Marked activation of oxidative stress (increased SOD activity (by 38.8-40.7%) reduced glutathione (52.4-90.0%) and TBARS concentrations (37.6-52.7%) in the nodal and non-nodal thyroid tissue in patients with multinodular colloid goiter suggest participation of free radical mechanisms in the disturbance of thyrocytes iodine metabolism and development of thyroid nodular pathology.

[The role of liver antioxidant system in predisposition of rats to hepatotoxic effect of ethanol]. / Rol' antioksidantnoi sistemy pecheni v predraspolozhennosti krys k gepatotoksicheskomu deistviiu étanola.

A new methodological approach capable of revealing factors responsible for the susceptibility of rat liver to ethanol hepatotoxicity has been developed. Using the correlation, dispersion, iteration, multifactor regression, and canonical analyses, a relation was established between the initial state of the liver antioxidant system and the character and degree of the subsequent ethanol-induced damage. In particular, it was found that intact animals with initially low level of reduced glutathione and retinols in the liver, as well as those with enzymopathy of cytosol HDNB-glutathione-8-transferase, are more susceptible to the ethanol liver damage.

[Characteristics of pantothenic acid transport in membrane vesicles of the brush border of small intestine epithelial cells in rats]. / Kharakteristiki transporta pantotenovoi kisloty v membrannykh vezikulakh shchetochnoi kaimy épitelial'nykh kletok tonkoi kishki krys.

A microfiltration method was used to study the mechanism of pantothenic acid transport in the membrane vesicles of the rat small intestine brush margin. The vitamin uptake proceeded to inner space of the vesicles and was enhanced in presence of sodium ions. The findings suggest that the vitamin transport across the membrane of the small intestine brush margin is mediated by a carrier and proceeds via a Na(+)-co-transport mechanism.

Some natural and synthetic antioxidants as stabilizers of beta-carotene conversion into vitamin A.

The effect of antioxidants (vitamins C and E, quercetin, probucol, butylated hydroxytoluene) on the oxidation of beta-carotene and its conversion into retinal under the influence of beta-carotene 15,15'- dioxygenase (CDO) from rat intestinal mucosa was studied. The activity of CDO decreased in the presence of oxidants. Antioxidants protected both the substrate and the enzyme. The extent of the protection depended on the antioxidant type. The combined injection of antioxidants and beta-carotene to animals completely or partially prevented the inhibition of the intestinal CDO which was caused by products of non-enzymatic oxidation of beta-carotene. Vitamins C and E, which protected the enzyme--substrate complex in vivo and in vitro, were found to be the most efficient protectors of beta-carotene conversion into retinal.

[Purification and various properties of pantothenate kinase from the rat liver]. / Ochistka i nekotorye svoistva pantotenatkinazy iz pecheni krys.

Homogeneous (according to disc gel electrophoresis data) ATP: D-pantothenate-4'-phosphotransferase (pantothenate kinase, EC 2.7.1.33) was obtained from rat liver cytosol of heterogeneous stock rats. The enzyme was purified 199-fold with a 9.3% yield. The enzyme was relatively unstable but retained its activity in the presence of 10% glycerol containing 5.10(-4) M ATP over 10 days at 4 degrees C. The pH optimum was 6.5; the apparent Km values were equal to 1.2 X 10(-5) M and 1.4 X 10(-3) M for pantothenate and ATP, respectively, at the ATP/Mg2+ ratio of 1. Pantetheine produced a competitive inhibition of pantothenate kinase. Pantethine or pantetheine disulfide did not inhibit the enzyme.

[Active transport of pantothenic acid in the small intestine of the rat]. / Aktivnyi transport pantotenovoi kisloty v tonkom kishechnike krys.

Pantotheric acid transport non-linear dependence was found in vivo and in vitro tests in the rat small intestine. Kinetic constants of the above process were determined. Dinitrophenol, sodium fluoride, anoxia, 4-phosphopantothenate and pantoilaminocaproic acid inhibited vitamin transfer against concentration gradient. Dependence of pantothenate transport rate upon sodium concentration was revealed.

[Antitoxic properties of pantothenic acid derivatives, precursors of coenzyme A biosynthesis, with regard to kanamycin]. / Antitoksicheskie svoistva proizvodnykh pantotenovoi kisloty, predshestvennikov biosinteza kofermenta A v otnoshenii kanamitsina.

The effect of calcium pantothenate (CPN)B 4'-phospho-CPN (PCP), pantetheine (PT) and calcium S-sulfopantetheine (SPN) on acute toxicity of kanamycin sulfate was studied on albino mice. The above derivatives of pantothenic acid except PT lowered the antibiotic toxicity. The coefficient of the antitoxic effect (LD50/ED50) of SPN and PCP was 1.3-1.4 times higher than that of CPN. The combined use of kanamycin (1/5 of the LD50) with CPN, PCP or PT (30 mg/kg bw was equivalent to CPN) for 15 days prevented the increase in the total content of CoA and in the content of the fraction of free CoA and the precursors of its biosynthesis participating in the reaction of N-acetylation in the liver and brain. The contents of these substances were within the normal during the whole experiment. A certain increase in the activity of pantothenate kinase in the liver cytosol due to the use of kanamycin was eliminated by the simultaneous use of PCP and PT. The vitamin-containing compounds PCP and SPN were recommended for the clinical trials as agents preventing complications of kanamycin therapy.

[Radiometric method of determining ATP: D-pantothenate-4'-phosphotransferase activity]. / Radiometricheskii metod opredeleniia aktivnosti ATP: D-pantotenat-4'-fosfotransferazy.

A radiometric procedure is developed for estimation of pantothenate kinase (EC 2.7.1.33) activity in various preparations of rat liver tissue; sodium 14C-D-pantothenate was used as a substrate and the reaction end product 4'-phosphopantothenic acid was measured. Optimal separation of the substrate and the end product was achieved by means of chromatography on DEAE-Sephadex A-25. 4'-phosphopantothenic acid was eluted from the column by 0.4 N HCl thus avoiding the label dilution and possible quenching of scintillation.