The effect of the angiotensin converting enzyme (ACE) inhibitor, captopril, on proteosynthesis in the aorta, acetylcholine-stimulated aortic relaxation and endothelaemia (circulating endothelial cells) was investigated in rabbits with aortic insufficiency. The animals were studied 28 days after experimental intervention. Cardiac volume overload stimulated proteosynthesis in the aorta as reflected by increased ribonucleic acid (RNA) concentration and [14C] leucine incorporation into proteins of the aorta. Moreover, the number of endothelial cells in the blood was increased. The administration of captopril starting from the second day of the haemodynamic overload, partially prevented the increase both in aortic proteosynthesis and in endothelaemia. Despite these alterations, the relaxing ability of the aorta to acetylcholine was not changed either by the haemodynamic overload or by captopril. We conclude that the increase of proteosynthesis in the aorta and of endothelaemia in the early period of chronic cardiac volume overload in rabbits were partially prevented by chronic captopril treatment. Neither aortic insufficiency nor captopril changed the acetylcholine-induced relaxation of the aorta.
Hereditary hypertriglyceridemic (hHTG) rats are characterized by increased blood pressure and impaired endotheliumdependent relaxation of conduit arteries. The aim of this study was to investigate the effect of long-term (4 weeks) treatment of hHTG rats with three drugs which, according to their mechanism of action, may be able to modify the endothelial function: simvastatin (an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase), spironolactone (an antagonist of aldosterone receptors) and L-arginine (a precursor of nitric oxide formation). At the end of 4th week the systolic blood pressure in the control hHTG group was 148±2 mm Hg and in control normotensive Wistar group 117±3 mm Hg. L-arginine failed to reduce blood pressure, but simvastatin (118±1 mm Hg) and spironolactone (124±4 mm Hg) treatment significantly decreased the systolic blood pressure. In isolated phenylephrine-precontracted aortic rings from hHTG rats endothelium-dependent relaxation was diminished as compared to control Wistar rats. Of the three drugs used, only simvastatin improved acetylcholine-induced relaxation of the aorta. We conclude that both simvastatin and spironolactone reduced blood pressure but only simvastatin significantly improved endothelial dysfunction of aorta. Prominent increase in the expression of eNOS in large conduit arteries may be the pathophysiological mechanism underlying the protective effect of simvastatin in hHTG rats., J. Török, I. L'upták, J. Matúšková, O. Pecháňová, J. Zicha, J. Kuneš, F. Šimko., and Obsahuje bibliografii
The aim of this study was to investigate whether the inhibition of one of the endothelial receptor sites in the rat pulmonary artery (muscarinic, histaminergic, purinergic, a 2-adrenergic) affects the NO-mediated relaxation induced by the activation of the other type of receptors. Acetylcholine (ACh)-, histamine (Hist)-, adenosine (Ade)- , and clonidine (Clon)-induced endothelium-dependent relaxations were reduced by the administration of specific antagonists of muscarinic, H1-histaminergic, purinergic or a 2-adrenergic receptors, respectively. The inhibition of H1-histaminergic receptors by chlorphenyramine did not prevent ACh-induced relaxation. Similarly, the inhibition of muscarinic receptors by atropine did not prevent the relaxations to histamine, adenosine and clonidine. On the other hand, the relaxations induced by acetylcholine, histamine, adenosine or clonidine were regularly reduced by NO-synthase inhibitor NG-nitro-L-arginine methyl ester (10-4 mol/l). These results suggest that the inhibition of NO-synthase abolished arterial relaxations induced by all agonists. After inhibition of one type of the endothelial receptors, the NO-dependent relaxation could still be evoked by activation of one of the others., S. Kyselá, J. Török., and Obsahuje bibliografii
Floating je doposud poměrně málo známou relaxační technikou. Ačkoli byla vynalezena již v 2. polovině 20. století, ještě se nestačila dostat do širšího povědomí jak veřejnosti, tak odborníků. Principem této techniky je pobyt v ničím nerušeném prostředí vodní nádrže ve tvaru vajíčka, naplněné hustým solným roztokem, umožňujícím se jako by vznášet. Odtud také název samotné techniky. Podmínky této techniky, omezující vnější rušivé stimuly, umožňují zažít hlubší pocit relaxace než u běžně dostupných relaxačních metod. Tento příspěvek se zaměřuje na připomenutí techniky floating a zmapování dosavadních poznatků o jejím relaxačním účinku. V textu je věnován prostor dostatečnému popisu této techniky, způsobu jejího využití jakožto relaxačního nástroje, dále je část textu věnována i historickému kontextu vývoje floatingu. V závěru se potom můžeme dočíst o pravidlech využívání této techniky a případných rizicích s ní spojených. and Floating is still a relatively little known relaxation technique. Although it was already invented in the second half of the 20th century, it still does not reach wider awareness of both the public and professionals. The principle of this technique is to stay in an undisturbed environment of a water tank in the shape of an egg, filled with a dense saline solution allowing „floating“. Hence the name of the technique itself. The conditions of this technique, restricting intrusive external stimuli, allow the experience of deeper relaxation than commercially available relaxation methods. This paper focuses on reminding and mapping existing knowledge of the relaxing effect of floating. In the text, sufficient space is dedicated to the description of this technique, to the method of its use as a relaxation tool and also to the historical context of the development of floating. A final part treats the rules for the use of this technique and potential risks associated with it.
The purpose of this study was to determine the relaxant effects of acetylcholine after inhibition of vascular histaminergic receptors. In isolated rings of the rat pulmonary artery precontracted by phenylephrine (10~5 mol/1) both histamine (10-7 to 10-4 mol/1) and acetylcholine (10-8 to 3xl0-5 mol/1) produced concentration-dependent relaxations. The arterial relaxations induced by either histamine or acetylcholine were markedly reduced or abolished by administration of NO synthase inhibitor NG-nitro-L-arginine methyl ester (10“5 mol/1). Relaxant responses to histamine were not influenced by cimetidine, histamine H2-receptor antagonist, but were significantly decreased or abolished by treatment with chlorphenyramine or diphenhydramine, histamine Hi-receptor antagonists. On the other hand, chlorphenyramine and diphenhydramine did not prevent the appearance of endothelium-dependent relaxation to acetylcholine. The results suggest that relaxation to histamine in the rat pulmonary artery is mediated by Hi-histaminergic receptors and their inactivation docs not interfere with the endothelial capability to produce and/or release nitric oxide by the activation of other types of receptors.
Let f be a rotationally invariant (with respect to the proper orthogonal group) function defined on the set M2×2 of all 2 by 2 matrices. Based on conditions for the rank 1 convexity of f in terms of signed invariants of A (to be defined below), an iterative procedure is given for calculating the rank 1 convex hull of a rotationally invariant function. A special case in which the procedure terminates after the second step is determined and examples of the actual calculations are given.
Optimization problems with stochastic dominance constraints are helpful to many real-life applications. We can recall e. g., problems of portfolio selection or problems connected with energy production. The above mentioned constraints are very suitable because they guarantee a solution fulfilling partial order between utility functions in a given subsystem U of the utility functions. Especially, considering U:=U1 (where U1 is a system of non decreasing concave nonnegative utility functions) we obtain second order stochastic dominance constraints. Unfortunately it is also well known that these problems are rather complicated from the theoretical and the numerical point of view. Moreover, these problems goes to semi-infinite optimization problems for which Slater's condition is not necessary fulfilled. Consequently it is suitable to modify the constraints. A question arises how to do it. The aim of the paper is to suggest one of the possibilities how to modify the original problem with an "estimation" of a gap between the original and a modified problem. To this end the stability results obtained on the base of the Wasserstein metric corresponding to L1 norm are employed. Moreover, we mention a scenario generation and an investigation of empirical estimates. At the end attention will be paid to heavy tailed distributions.