Is the common 844ins68 polymorphism in the cystathionine beta-synthase gene associated with atherosclerosis?
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Adolescent↗
Biomedical subjects
M Stefek
Publications and source records attributed to M Stefek.
2,4-dinitrophenylhydrazine carbonyl assay in metal-catalysed protein glycoxidation.
Using an experimental in vitro glycation model, long-term incubations of bovine serum albumin with glucose (fructose) resulted in a significant increase in protein content of 2,4-dinitrophenylhydrazine (DNPH)-reactive carbonyl groups, which could be strongly inhibited by anaerobiosis and metal chelation. The pattern of yields of the protein-bound DNPH was not in accordance with that of the sugar-derived carbonyls determined as the ketoamine Amadori product. In spite of the fact that the contribution of the final advanced glycation end-products to the total DNPH-reactivity of glycation-altered protein remains unclear, the present results stress the need of oxidative steps in formation of most of the DNPH-reactive carbonyl compounds generated by glycation. The results provide evidence that, in protein glycoxidation, the DNPH assay is selective enough to discriminate between protein-bound carbonyls produced by metal-catalysed oxidations and those formed in the early glycation steps.
Copper↗
Streptozotocin-induced experimental diabetes in male Wistar rats.
The aim of the present work was to test the sensitivity of young male Wistar rats, Dobrá Voda (Dv:WI) to the diabetogenic effect of streptozotocin (STZ) with regard to their health condition and mortality rates. Eight-week-old rats, weighing from 200 to 230 g, were randomised into five groups of eight animals. Streptozotocin was administered by i.v. injection in doses of 40, 50, 60 and 70 mg/kg body weight. The animals were kept on a standard diet with free access to water for 4 months. The highest STZ dose (70 mg/kg) was lethal to the animals, the doses of 50 and 60 mg/kg induced persistent hyperglycaemia with glucose levels above 20 mM. Body weights of STZ treated rats from all experimental groups were significantly lower than those of control animals. Considerable polyuria was observed in all STZ treated rats. About 40% of the STZ treated animals were found to develop overt cataract between days 90 and 100. At the end of the experiment, significant albuminuria was observed in the experimental groups administered 50 and 60 mg/kg STZ doses. We conclude that young male Wistar rats, Breeding Facility Dobrá Voda (Dv:WI), Slovakia, treated by a single i.v. STZ dose of 50 or 60 mg/kg developed a persistent disease state characterised by severe hyperglycaemia with major clinical signs of diabetes mellitus.
Animals↗
Streptozotocin diabetes-induced changes in aorta, peripheral nerves and stomach of Wistar rats.
In rats with diabetes induced by streptozotocin (STZ), we studied the reactivity of the aorta in response to vasoconstrictor and vasorelaxant agents, changes in conduction velocity in the sciatic nerve, and glutathion (GSH) content in the gastric mucosa as well as the occurrence of spontaneous gastric lesions. STZ-induced diabetes was found to be accompanied by endothelial injury, exhibited by diminished endothelium-dependent relaxation and by increased noradrenaline- and H2O2-induced contraction. Conduction velocity in the nerves from STZ-treated animals was significantly lower compared to that in nerves from control animals. Moreover, gastric hyperaemia, occasional gastric lesions, and a significant depletion of GSH in the gastric mucosa were observed in STZ-treated rats. Our experiments confirmed the suitability of Wistar rats for the model of STZ-induced diabetes.
Acetylcholine↗
[Sonographic measurement of intimal thickness of the common carotid artery in diabetics].
Incidence of atherosclerotic cardiovascular diseases in diabetics is known to be 2-4 times higher than in nondiabetic subjects. Intima-media-thickness of common carotid artery (IMT ACC) measured by B-mode sonography positively correlates with the severity of atherosclerotic changes in coronary arteries. This study compares sonographically assessed IMT ACC in patients with type 2 diabetes mellitus (27 patients, mean age 66.57 +/- 6.06 years) vs. 66 nondiabetic subjects (mean age 63.58 +/- 9.09 years). Intima-media thickness in diabetics was significantly higher when compared with the control group (0.826 +/- 0.29 mm vs. 0.647 +/- 0.26 mm). In the whole cohort of investigated subjects IMT ACC positively correlates with age. When adjusted for age, the mean IMT ACC level was significantly higher in men than in women.
Aged↗
Epidemiology tools program and selected medical applications.
In epidemiological research the calculation of appropriate measures of disease frequency is the basis for a comparison of populations and, therefore, the identification of disease determinants. Two frequencies being compared can be combined into a single summary parameter that estimates the association between an exposure and a disease. This can be accomplished by calculating either the ratio of the measures of disease frequency for two populations which indicates how much more likely one population is to develop a disease than another, or the difference between the frequencies which indicates how much greater the frequency of a disease is in one population compared with the other. In epidemiology we often need to compute measures of disease frequency mentioned above. We can do that by means of complex statistical software, but sometimes it is not easy or possible to use this software for an analysis of epidemiological data. At the EuroMISE Center of Charles University and Academy of Sciences in the framework of the research supported from grant COPERNICUS JRP-10053 the E. T. program (Epidemiology Tools) was developed. This program can be used for practical analysis of data from retrospective (case-control) studies or prospective (cohort) studies and for standardization. However, the program can be also a useful teaching tool in the epidemiology courses.
Adolescent↗
Decision support and data analysis tools for risk assessment in primary preventive study of atherosclerosis.
In the paper we show results of two programs applied for data analysis and decision support in primary preventive study of atherosclerosis. First program E.T. (Epidemiology Tools) can be used for analysis of data from retrospective (case-control) studies, prospective (cohort) studies and for standardization. Second program called CORE (COnstitution and REduction) supports the process of selection of features that are relevant for given decision making task. Program CORE is using information theory approach. Both these programs were applied to analysis of data about 1417 middle age men collected in the longitudinal study on atherosclerosis in urban population. Apart from these two new programs we have analyzed data also by the STATISTICA software.
Adult↗
Evaluation of data in cardiology by new software tools.
We describe an analysis of cardiology data using new software tools. First we use data of 1417 men aged 40 to 50 years living in the center of Prague gathered in the twenty years lasting longitudinal study. We show some results of application of the programs E.T. (Epidemiology Tools) and CORE (COnstitution and REduction of data). Second we show the way of application of the program HYPERTENSION, that supports decision making in therapy of arterial hypertension.
Adult↗
The pyridoindole antioxidant stobadine inhibited glycation-induced absorbance and fluorescence changes in albumin.
We studied the effect of the pyridoindole antioxidant stobadine on glycation-induced absorbance and fluorescence changes in bovine serum albumin (BSA), used as a model protein. Incubation of BSA (4 mg/ml) with glucose (100-400 mM) in 0.12 M phosphate buffer, pH 7.4, in the presence of 100 microM Cu2+ at 37 degrees C resulted in a time-dependent increase of absorbance (320 nm) and fluorescence (excitation 350 nm, emission 415 nm). The process was found to be dependent on the presence of oxygen and transition metal ions, but equimolar iron could not fully substitute for the activity of copper. The glucose-induced chromo- and fluorophore formation was reduced significantly by stobadine. For 200 mM glucose, in 7- and 14-day incubations, 51%-60% inhibition was obtained at a stobadine concentration of 0.1 mM, and the effect leveled off at higher concentrations of the drug. No inhibition was observed with N-acetyl stobadine, a derivative with restricted antioxidant activity. Since stobadine did not affect the Amadori product formation determined by the thiobarbituric acid (TBA) method as 5-hydroxymethyl furfural (5-HMF) released in boiling oxalic acid, the inhibitory action of stobadine may be explained by its interference with metal-catalyzed oxidation reactions following after the glycation step. The results obtained suggest that antioxidant therapy could be used to limit the damage from adverse glycation-induced processes in diabetes mellitus.
Animals↗
The pyridoindole antioxidant stobadine prevents alloxan-induced lipid peroxidation by inhibiting its propagation.
Under in vitro conditions, the pyridoindole stobadine inhibited alloxan-induced lipid peroxidation in a model biological membrane with the efficacy comparable with that of the standard Trolox. Intermediary alloxan radicals and hydroxyl radicals were not directly involved in the process of lipid peroxidation, however, the presence of iron chelate was a necessary prerequisite. Since stobadine did not affect the kinetics of alloxan redox-cycling in the presence of GSH, we suggest that the protective action of stobadine against the alloxan-induced lipid peroxidation was mediated predominantly by its ability to quench peroxyl radicals, inhibiting thus the propagation stage of the oxidative damage. The results also indicate that toxic effects of alloxan may well be mediated by mechanism(s) not involving hydroxyl radicals.
Alloxan↗
Inhibition of alloxan-induced hyperglycaemia in mice by the pyridoindole stobadine.
Alloxan-induced hyperglycaemia was used as a model of free radical pathology to test the antioxidant activity of the pyridoindole drug, stobadine, in the intact mouse. Stobadine was injected intraperitoneally in a dose range 7.5-60 mg/kg prior to intravenous injection of alloxan (50 mg/kg), and blood glucose concentration 72 hr after alloxan administration was used as an index of alloxan toxicity. Stobadine efficiently suppressed the alloxan-induced hyperglycaemia in a dose-dependent manner. This protection against the diabetogenic effect of alloxan is consistent with the high efficacy of stobadine to scavenge hydroxyl radicals.
Alloxan↗
In vitro studies on the activity of japanese kampo herbal medicines Oren-Gedoku-To (TJ-15) and Toki-Shakuyaku-San (TJ-23) as scavengers of free radicals.
Oren-Gedoku-To (TJ-15) inhibited enzymatically (NADPH or CumOOH) and non-enzymatically (Fe-ascorbate) induced lipid peroxidation in rat liver microsomes as assessed by TBA-reactive product accumulation. Toki-Shakuyaku-San (TJ-23) had little effect on either system. The protective effect of TJ-15 against lipid peroxidation was not dependent upon the presence of microsomal drug-metabolizing activity and could not be fully accounted for by its action on microsomal electron transfer, as evaluated by studying the kinetics of cytochrome c reduction. Both TJ-15 and TJ-23 reduced the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH), indicating their free radical scavenging ability. The reactivity of TJ-15 was comparable with that of standard ascorbate, while the activity of TJ-23 was approximately 10 times lower. In a free solution TJ-15 and TJ-23 effectively scavenged OH* radicals, as indicated by the inhibition of ethylene production from 2-keto-4-methiolbutyric acid (KMBA), and O2*- anion radicals, as assessed by the inhibitory effect on the rate of nitro blue tetrazolium (NBT) reduction by the O2*- generating system xanthine/xanthine oxidase.
Animals↗
Effect of Kampo medicines on alloxan-induced diabetes in mice.
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Animals↗
In vitro studies on the interaction of the pyridoindole antioxidant stobadine with rat liver microsomal P450.
1. Stobadine, a pyridoindole antioxidant agent, elicited medium affinity, low capacity interaction with type I binding sites of the hepatic microsomal cytochromes P450 derived from control and acetone-pretreated rats. Reverse type I interaction of low affinity and low capacity was observed in microsomes from phenobarbital-treated rats. 2. Stobadine led to an increase of H2O2 production when added to liver microsomes derived from differently pretreated rats in an NADPH-dependent process with concomitantly increased oxygen consumption. 3. Stobadine, at concentrations stimulating H2O2 formation, was found to prevent NADPH-induced microsomal lipid peroxidation, assessed as thiobarbituric acid-reactive product accumulation. 4. Only a weak inhibitory effect of stobadine on either NADPH- or cumene hydroperoxide-dependent aminopyrine N-demethylation and aniline hydroxylation was observed in microsomes from control and phenobarbital-pretreated rats. An approximately 10 times higher inhibitory potency towards aminopyrine N-demethylase activity was observed in acetone-pretreated rats. 5. In spite of the direct interaction of stobadine with microsomal P450, the compound only marginally affected aminopyrine and aniline metabolism both by monooxygenase and peroxidase modes of action of the P450 enzyme system. The potent antioxidant activity of stobadine was not diminished by the ability of the drug to stimulate the oxidase function of P450.
Animals↗
Inhibition of cumene hydroperoxide-induced lipid peroxidation by a novel pyridoindole antioxidant in rat liver microsomes.
The ability of stobadine, a novel pyridoindole antioxidant, to inhibit lipid peroxidation induced by cumene hydroperoxide was investigated in rat liver microsomes. In the micromolar range stobadine effectively inhibited lipid peroxidation as measured by the formation of thiobarbituric acid reactive products. The peroxidation-related degradation of microsomal cytochrome P-450 was prevented by stobadine in the same pattern. Another line of evidence in support of the antioxidant action of stobadine was given by its inhibition of cumene hydroperoxide-induced oxygen consumption in microsomal incubations. Inhibition of lipid peroxidation was not a function of decreased bioactivation of cumene hydroperoxide, as stobadine did not affect the rate of cytochrome P-450 dependent cleavage of cumene hydroperoxide. Neither had stobadine any effect on cytochrome P-450 peroxidase function characterized by the rate of cumene hydroperoxide-dependent oxidation of TMPD, and no direct spectral interaction with microsomal cytochrome P-450 was observed in the micromolar region. We suggest that it is the ability of stobadine to scavenge alkoxyl and peroxyl radicals that is predominantly responsible for the observed antioxidant effect.
Animals↗
Cytochrome P-455 nm complex formation in the metabolism of phenylalkylamines. XIII. Enzyme interactions with a series of beta-alkyl-substituted 2-phenylethanamines and corresponding N-hydroxylamines.
The formation of Metabolic Intermediate (MI) complexes from a series of beta-alkylsubstituted 2-phenylethanamines and corresponding N-hydroxylamines is investigated during NADPH-dependent metabolism in liver microsomes from phenobarbital pretreated rats. The beta-alkyl substituents are methyl, dimethyl, ethyl, di-ethyl, n-propyl, di-n-propyl and i-propyl groups. The amines are synthesized by LiAlH4-reduction of the corresponding nitriles, which are prepared through alkylation of the enolate anion of phenylacetonitrile. The hydroxylamines are prepared either by oxidation of the corresponding benzylimines with m-chloroperbenzoic acid and subsequent hydrolysis of the initially formed 3-phenyloxaziridines, or by H2O2-mediated oxidation of the corresponding amines in the presence of catalytic amounts of sodium tungstate, followed by reduction with cyanoborohydride. The amines are found to be completely devoid of complexing activity, while the hydroxylamines form the MI complex at high rates. Complex formation from these substrates thus parallels the known behaviour of 2-phenylethanamine and its corresponding N-hydroxylamine. Since N-oxygenation is known to be a prerequisite for MI complex formation from amines our results suggest that the beta-alkylated 2-phenylethanamines are metabolized exclusively through other pathways. In accordance with this hypothesis, capillary GC-analysis of the incubation mixture of 2-phenylpropanamine shows no formation of N-hydroxylated metabolites; only 2-phenylpropanol, a metabolite formed through the deamination pathway, is found.
Amines↗
[Antioxidative activity of oren-gedoku-to (TJ-15) and toki- shakuyaku-san (TJ-23) in the liver microsomes of rats].
TJ-15 (Oren-Gedoku-To) inhibited enzymatically (NADPH or CumOOH) and non-enzymatically (Fe-askorbate) induced lipid peroxidation in the rat liver microsomes as assessed by the TBA-reactive product accumulation. TJ-23 (Toki-Shakuyaku-San) had little effect on either system. The protective effect of TJ-15 against lipid peroxidation could not be fully accounted for by its action on microsomal electron transfer, as evaluated by studying the kinetics of reduction of cytochrome C. In a free solution TJ-15 and TJ-23 effectively scavenged OH., radicals, as indicated by the inhibition of ethylene production from KMBA, and O2-. anion radicals, as assessed by the inhibitory effect on the rate of NBT reduction. The present results suggest that TJ-15, yet not TJ-23, is capable to reach hydrophobic intra-membrane sites at concentrations at which it is an effective antioxidant. Thus TJ-15 may be a potentially useful protective agent against free radical-mediated damage.
Animals↗
Pyridoindole stobadine is a potent scavenger of hydroxyl radicals.
Stobadine is a potent scavenger of OH. radicals generated chemically in a free solution with kappa 2 higher than 10(10).M-1.s-1 as determined by two independent methods, namely destruction of deoxyribose and oxidation of 2-keto-4-methiolbutyric acid (KMBA). The high efficacy of stobadine to prevent ethylene production from KMBA was observed also in enzymatic (xanthine-xanthine oxidase-driven Fenton) and membrane-bound (NADPH-dependent microsomal electron transfer) sources of OH. radicals.
Animals↗