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Biomedical subjects

P Svec

Publications and source records attributed to P Svec.

At least 55 records · Page 3Linked to original sources

[Antiexsudative activity of (methylsalicylate)copper-water compounds].

Using rat paw dextran edema, the antiexudative activity of the complexes of the composition Cu(RCOO)2.nH2O--R represents 2-hydroxy-Y-phenyl: Y = 3 (n = 1,5), Y = 4 (4), Y = 5 (2) or 2-hydroxy-3,6-dimethylphenyl (n = 4)--and of the corresponding uncomplexed acids was assayed. Salicylic and acetylsalicylic acids and their Cu(II) salts were used as standards of comparison. The compounds were administered i.p. in a single dose of 10 mg/kg body weight. In general, the acids were more effective than their copper(II) salts except for the pair m-cresotic acid--Cu(II) complex. Only p-cresotic acid (mean edema reduction 56%) and copper(II) m-cresotate tetrahydrate (43%) exhibited a biological activity comparable to those of salicylic acid (62%) and copper(II) salicylate tetrahydrate (70%). The observed activities of complexes are discussed in relation to their proposed structures.

Animals↗

[Pharmacologic control of reperfusion dysrhythmias].

The present study aims to investigate the effects of the lipophilic antioxidant Trolox C (a vitamin E analogue) and stobadine, a scavenger of free oxygen radicals, on reperfusion dysrhythmias. Experiments were performed on isolated perfused rat hearts subjected to global stop-flow ischaemia followed by reperfusion. Trolox C (10(-4 mol.l-1) and stobadine (10(-5) mol.l-1) were infused immediately prior to ischaemia. Trolox C (10(-4) mol.l-1) and stobadine (10(-5) mol.l-1) decreased the incidence and duration of reperfusion-induced dysrhythmias (quantified by the dysrhythmia score) in comparison to the ischaemic-reperfusion damaged hearts. There was an improvement in the recovery of contraction force and left ventricular diastolic pressure in Trolox or stobadine pretreated hearts. No significant changes in coronary flow resistance were observed. The results suggest that both substances protect the myocardium during ischaemic-reperfusion injury probably by affecting the generation and activity of reactive oxygen species.

Animals↗

[Free oxygen radicals in the pathogenesis of ischemic-reperfusion heart damage and possibilities of its pharmacologic control].

Due to their molecular configuration, most free radicals are highly reactive and can cause cell injury. The present review deals with the role of oxygen-free radicals (OFR) in the pathogenesis of the heart disease and reperfusion injury. Cellular protection against deleterious effects of OFR is organized at multiple levels. Regulation of the antioxidant capacity includes not only the maintenance of adequate levels of antioxidants but the localisation of antioxidant compounds and enzymes as well. Synthetic antioxidants may mimic biological defence mechanisms.

Animals↗

Carbamate analogues of tocainide.

A series of the new aminoalkyl esters of chlor-, methyl- and alkoxy carbanilates was synthesized. All the compounds prepared were found to exhibit antiarrhythmic activities comparable with those of mexiletine.

Aconitine↗

Partially phosphorylated phosphorylase in the rat heart after beta-receptor stimulation in vivo.

The formation of the phosphorylase ab hybrid and its further transformation into phosphorylase a has been demonstrated in the rat heart after different periods of i.v. isoproterenol administration. Phosphorylase ab hybrid was determined in the presence of AMP and/or caffeine. Only the partially phosphorylated phosphorylase was found in the control rat hearts and its activity was 30% of the total phosphorylase. The phosphorylase ab hybrid was disclosed particularly after small isoproterenol doses (0.031-0.062 microgram.kg-1) and at short time interval (15 s) after its administration. Higher isoproterenol doses (0.25-0.5 microgram.kg-1) changed the partially phosphorylated phosphorylase to phosphorylase a (58%) after a longer time interval (40 s). The phosphorylase ab hybrid was revealed even at the maximal rate of stimulation. The formation of the phosphorylase ab hybrid in the rat heart in vivo appears to be of physiological significance. Our results confirmed the earlier suggestion that the -AMP/+AMP activity ratio reflects the percentage proportion of the phosphorylated subunits of phosphorylase but not of the activated phosphorylase molecules.

Adenosine Monophosphate↗

[Radioprotective effects of basic copper carboxylate complexes].

The radioprotective activity of eight selected copper (II) carboxylates--Cu (RCOO)2.nL (R = alkyl, aryl, 2-furyl and 2-thienyl; L usually represents water)--was assayed in a model of lethally gamma-irradiated (9 Gy, 0.97 Gy/min) mice. The compounds tested were applied (as solutions in saline) s.c. in three single doses of 20 mumol/kg 48.24 and 6 h before irradiation. The highest radioprotective effects were measured by survival of mice achieved after premedication of animals with copper (II) 2-thenoate monohydrate (77%), copper (II) acetylsalicylate (64%), copper (II) 2-methoxybenzoate monohydrate (62%) and copper (II) acetate monohydrate (54%). On the other hand, survival of vehicle-pretreated mice was only 10%. The observed biological properties of complexes are discussed in relation to their structures.

Animals↗

[The effect of butylhydroxyanisole, an antioxidant, on oxidative phosphorylation of myocardial mitochondria in experimental ischemia].

The present paper evaluated the effect of the antioxidatively acting agent butylhydroxyanisole (BHA) on the oxidative and energetic processes in the mitochondria of the myocardium, both normal and damaged with isoprenaline. BHA was administered for 20 days in a daily dose of 10 mg.kg-1. Experimental necrosis of the myocardium was induced by a single-dose administration of a dose of 25 mg.kg-1 s.c. The results shown in Graphs 1-7 indicate that BHA in the above-mentioned concentration did not act protectively on the metabolic processes taking place in the mitochondria during experimentally induced necroses of the myocardium.

Animals↗

[Development of a withdrawal syndrome in a neonate after long-term therapy of the mother with metipranolol during pregnancy].

The authors describe the withdrawal syndrome of a beta-adrenolytic in neonates manifested above all 10-16 hours after delivery by alternating bradycardia and marked tachycardia independently on the infant's activity. The withdrawal syndromes correlate with the increased heart rate of the mother after delivery. The authors draw attention to the fact that the withdrawal syndrome in the neonate may develop after delivery if the mother used during pregnancy not only addictive drugs affecting the central nervous system but also drugs affecting the cardiovascular system such as the beta-adrenolytic metipranolol.

Adult↗

[Anti-ulcer effectiveness of mono- and dibasic carbamates with local anesthetic effects].

An evaluation of anti-ulcer effects of mono- and dibasic carbamate local anaesthetics was performed using two experimental models of gastric ulcers, i.e. those induced by stress, or by ligation of the pylorus. These models have been found not to be identical. In the case of stress-induced ulcers, no experimental animal died as compared to the second experimental group with a 30% mortality rate due to the more frequent occurrence of ulcer perforations. Result similarities of both models could only be found with respect to the range of damage of the mucous membrane of the stomach. A premedication with a majority of basic carbamates decreased the incidence and range of ulcer lesion. The anti-ulcer activity of monobasic carbamates was more significant when compared with dibasic compounds.

Anesthetics, Local↗

Biochemical, structural and ultrastructural changes in the Prague hereditary hypercholesterolemic (PHHC) rats heart after the long treatment with calcium channel blockers.

Elevated plasma cholesterol concentration may be important in the initiation of heart ischemia and progression of atherogenesis. It has been shown that drugs affecting calcium entry into cells can attenuate the development of this cholesterol induced changes. The aim of this work was to study the influence of five calcium channel blockers 6 weeks treatment on some parameters of lipid metabolism, morphological and ultrastructural changes in the Prague hereditary hypercholesterolemic (PHHC) rats myocardium. The calcium antagonists were administered twice daily perorally in the following doses: nifedipine and nitrendipine 0.2 mg.kg-1, nimodipine 2.5 mg.kg-1, verapamil and diltiazem 1.0 mg.kg-1 body weight. Cholesterol diet decreased the level of free fatty acids significantly (from 5.59 +/- 0.216 to 3.83 +/- 0.371 mumol.g-1), increased the level of total cholesterol (from 28.0 +/- 1.92 to 34.0 +/- 2.90 mumol.g-1) and caused micronecrosis. Examination of myocardial ultrastructure showed a frequent occurrence of lysosomes as well as large numerous autophagic vacuoles and contracture bands of myofibrils. These effects were partly suppressed by calcium channel blockers verapamil and diltiazem, but dihydropyridines were not effective. Observed biochemical changes were in accordance with structural and ultrastructural investigations.

Animals↗

Synthesis and local anesthetic activity of some derivatives of N,N-diethyl-2-(2-alkoxyphenylcarbamoyloxy)bornan-3-ylmethyl-ammonium chlorides.

A series of 8 new esters of 2-alkoxyphenyl-carbamoic acid were synthesized and assayed for local anesthetic activity. All compounds were isolated as hydrochlorides and their structure was proved by 1H-NMR 13C-NMR and IR spectroscopy. The index of anesthetic activity in infiltration and surface anesthesia proved that all prepared compounds are significantly more active than the standard reference compounds, procaine and cocaine, respectively; it is tightly correlated with the length of the alkoxy group. It was found that there is a parabolic relationship between log activity and molecular lipophilicity (as measured by RM). Toxicity of all compounds is within acceptable limits.

Anesthetics, Local↗

[Local anesthetics. CX. Preparation, activity and partition coefficients of pyrrolidinoethylesters of 2-, 3- and 4-alkoxy-substituted phenylcarbamic acids].

By pyrrolidinoethylalcohol addition on 2-, 3- and 4-alkoxy-substituted phenylisocyanate in non-aqueous toluene medium a series of 30 compounds of the type Pyrrolidinoethylesters of 2-, 3- and 4-alkoxy substituted phenylcarmabim acids were prepared. Pharmacological evaluation results shown after comparing with cocaine and procaine standards that these compounds have a higher index of effectiveness in both types of local anaesthesia. The maximum effectiveness of surface anaesthesia shows Pyrrolidinoethylester of 2-octyloxy phenylcarbamic acid which is 204-times more effective as cocaine. The maximum effectiveness of infiltration anaesthesis shows Pyrrolidinoethylester of 2-heptyloxy phenylcarbamic acid which is 66-times more effective as procaine. Prepared compounds are more effective in the case of surface anaesthesia as in the case of infiltration anaesthesia and they have comparatively high values of partition coefficients P' and P' cal. Comparison of prepared compounds effectiveness and analogic piperidinoethylesters shows that in more cases they are either equal or nearer effective. The values of their P' and P' cal correlate with these results.

Anesthetics, Local↗

[The effect of calcium channel blockers in experimental myocardial infarct in rats].

The effect of the blockers of calcium channels on the development of myocardial ischaemia in rats with an occlusion of the coronary artery was examined. An occlusion of the coronary artery was carried out in rats anaesthetized with pentobarbital by tightening the ends of the ligature freely placed under the left coronary artery - ramus interventricularis seven days prior to ligation. The ischaemia-induced changes in the R-wave and ST-segment were recorded using ECG. The occlusion of the coronary artery produced arrhythmias, a significant elevation of the ST-segment and a slight increase in the heart rate. The blockers of calcium channels with different pharmacological properties - verapamil, nifedipine and diltiazem influenced the ischaemia-induced changes with different intensity. Nifedipine (0.02 mg.kg-1, i.v., 30 min prior to occlusion), verapamil (0.2 mg.kg-1, i.v., 10 mins prior to ischaemia), and diltiazem (0.3 mg.kg-1, i.v., 10 mins prior to ischemia) significantly reduced the increased elevation of the ST-segment. The highest effect on the above-mentioned model was shown by verapamil.

Animals↗

[Anti-inflammatory activity of aqua-(aryloxyacetate) copper complexes].

The anti-inflammatory activity of selected mononuclear Aqua(aryloxyacetato)copper(II) complexes with the composition [Cu(R-O-CH2COO)2(H2O)n].mH2O (R = phenyl, n = 3; m = 0), 4-chlorophenyl (2; 0), 4-chloro-2-methylphenyl (2; 0) and naphthyl (2; 2) was examined using rat paw dextrano edema. The antiphlogistic effects of the tested complexes were compared to those for corresponding aryloxyacetic acids and salicylic acid and its Cu(II) salt. The compounds were administered i.p. in a single effective dose of 10 mg/kg. The complexes with R = phenyl, 4-chlorophenyl and 4-chloro-2-methylphenyl exhibited a biological activity comparable to that of copper(II) salicylate tetrahydrate.

Animals↗

[Anti-pyretic activity of aqua-(diacetoxybenoate)-copper complexes].

The antipyretic activity of binuclear (diacetoxybenzoato)-copper(II) aquacomplexes [Cu2(2,Y-DAB)4(H2O)2] (Y = 4 and 5) as well as cupric acetylsalicylate [Cu2(AcSal)4] was assayed in a rabbit model of endotoxin-induced fever. The complexes and uncomplexed carboxylic acids (administered i.p. in a dose of 20 mg/kg) exhibited even a subnormothermic course in lowering of febrile animals' body temperature in the order: 2,5-diacetoxybenzoic acid (-0.09 degree C) < 2,4-diacetoxybenzoic acid (-0.35 degree C) < Cu(AcSal)2(-0.39 degree C) approximately equal to acetylsalicylic acid (-0.40 degree C) < Cu(2,4-DAB)2.H2O (-0.61 degree C) < Cu(2.5-DAB)2.H2O (-0.97 degree C). On the other hand, the mean value of untreated fevered animals was +0.67 degree C.

Animals↗