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602. Microalbuminuria versus brain natriuretic peptide in cardiac hypertrophy of hypertensive rats
- Creator:
- Saliba, Y., Chouery, E., Mégarbané, A., Jabbour, H., and Farès, N.
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, hypertenze, hypertension, microalbuminuria, brain natriuretic peptide, cardiac hypertrophy, 14, and 612
- Language:
- English
- Description:
- The objective of this study was to assess a possible link between microalbuminuria (MA), a major ri sk factor of the cardiorenal syndrome and the brain natriuretic peptide (BNP), a marker of cardiac hypertrophy. Two kidney-one clip (2K-1C) renovascular hypertension was induced in 24 male Wistar rats (weighing 220-250 g). Rats were randomized into four groups for 8 weeks: Sham, not treated; Bos, treated with bosentan; Cap, treated with captopril; Bos/Cap, treated with both drugs. Blood pressure, plasma BNP and transforming growth factor β1 (TGF-β1) concentrations, microalbuminuria and creatininemia as well as cardiac mass, BNP, α- and β-myosin heavy chain (MHC) gene expression and kidney histology were determined. Following stenosis, Sham rats developed hypertension (p<0.001), an increase in BNP (p<0.05) and TGF-β1 (p<0.005) concentrations, creatinine levels (p<0.001), and urinary albumin (p<0.001). Under drug treatment, decreases in blood pressure (p<0.001), creatinine levels (p<0.05), plasma TGF-β1 (p<0.005) and BNP (p<0.05) concentrations, were co ncomitant with the absence of MA which was significantly correlated with reductions in cardiac mass (p<0.05) and hypertrophy markers (BNP and β-MHC gene expression) (p<0.005) as well as in renal fibrosis. These findings suggest a potential link between microalbuminuria evolution and BNP as well as a possible effect of microalbuminuria-lowering therapy on halting the progression, or even inducing the regression of cardiac hypertrophy., Y. Saliba, E. Chouery, A. Mégarbané, H. Jabbour, N. Farès., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
603. Microcirculation in pregnancy
- Creator:
- Abdo, I., George, R. B., Farrag, M., and Černý, V.
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, těhotenství, preeklampsie, diabetes mellitus, pregnancy, preeclampsia, microcirculation, gestational, 14, and 612
- Language:
- English
- Description:
- The microcirculation, like all physiological systems undergoes modifications during the course of pregnancy. These changes aid the adaption to the new anatomical and physiological environment of pregnancy and ensure adequate oxygen supply to the fetus. Even though the microcirculation is believed to be involved in major pregnancy related pathologies, it remains poorly understood. The availability of safe and non-interventional technologies enabling scientists to study the intact microcirculation of the pregnant patient will hopefully expand our understanding. In this article we review the physiological changes occurring in the microcirculation during pregnancy and the role of the microcirculation in gestational related pathologies. We will also describe the available techniques for the measurement and evaluation of the microcirculation. Lastly we will highlight the possible fields in which these techniques could be utilized to help provide a clearer view of the microcirculation in the pregnant woman., I. Abdo, R. B. George, M. Farrag, V. Cerny, C. Lehmann., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
604. Microinjection of salusin-β into the nucleus tractus solitarii inhibits cardiovascular function by suppressing presympathetic neurons in rostral ventrolateral medulla in rats
- Creator:
- Lu, Y., Wu, Y. S., Chen, D. S., Wang, M. M., Wang, W. Z., and Yuan, W. J.
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, neurony, physiology, neurons, salusin, medulla, baroreflex, presympathetic neuron, rat, 14, and 612
- Language:
- English
- Description:
- Salusin-β is newly identified bioactive peptide of 20 amino acids, which is widely distributed in hematopoietic system, endocrine system, and the central nervous system (CNS). Although salusin- β extensively expressed in the CNS, the central cardiovascular functions of salusin-β are unclear. Our main objective was to determine the cardiovascular effect of microinjection of salusin-β into the nucleus tractus solitarii (NTS) in anesthetized rats. Bilateral or unilateral microinjection of salusin-β (0.94-94 μg/rat) into the NTS dose-dependently decreased blood pressure and heart rate. Bilateral NTS microinjection of salusin-β (9.4 μg/rat) did not alter baroreflex sensitivity. Prior application of the glutamate receptor antagonist kynurenic acid (0.19 μg/rat, n=9) into the NTS did not alter the salusin-β (9.4 μg/rat) induced hypotension and bradycardia. However, pretreatment with the GABA receptor agonist muscimol (0.5 ng/rat) within the rostral ventrolateral medulla (RVLM) completely abolished the hypotension (-14±5 vs. -3±5 mm Hg, P <0.05) and bradycardia (-22±6 vs. -6±5 bpm, P <0.05) evoked by intra-NTS salusin-β (9.4 μg/rat). In addition, we found that vagotomy didn’t influence the actions of salusin-β (9.4 μg/rat) in the NTS. In conclusion, our present study shows that microinjection of salusin-β into the NTS significantly produces hypotension and bradycardia, presumably by suppressing the activities of presympathetic neurons in the RVLM., Y. Lu, Y. S. Wu, D. S. Chen, M. M. Wang, W. Z. Wang, W. J. Yuan., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
605. Microvascular endothelial cells from human omentum lack an inward rectifier K+ current
- Creator:
- Himmel, H. M., Rauen, U., and Ravens, U.
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- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, whole-cell voltage clamp, ion substitution, non-excitable cells, Na+ background current, chloride conductance, CA 2+ - activated K+ current, 14, and 612
- Language:
- English
- Description:
- In most macrovascular endothelial cell (EC) preparations, resting membrane potential is determined by the inwardly rectifying K+ current (IK1), whereas in microvascular EC the presence of IK1 varies markedly. Cultured microvascular EC from small vessels of human omentum were examined by means of the voltage-clamp technique to elucidate the putative role of IK1 in maintaining resting membrane potential. Macrovascular EC from human iliac artery and bovine aorta served as reference. Human omentum EC showed an outwardly rectifying current-voltage relation. Inward current was hardly sensitive to variations of extracellular [K+] and Ba2+ block suggesting lack of IK1. However, substitution of extracellular [Na+] and/or [Cl-] affected the current-voltage relation indicating that Na+ and Cl- contribute to basal current. Furthermore, outward current was reduced by tetraethylammonium (10 mM), and cell-attached recordings suggested the presence of a Ca2+-activated K+ current. In contrast to human omentum EC, EC from human iliac artery and bovine aorta possessed inwardly rectifying currents which were sensitive to variations of extracellular [K+] and blocked by Ba2+. Thus, the lack of IK1 in human omentum EC suggests that resting membrane potential is determined by Na+ and Cl- currents in addition to K+ outward currents., H. M. Himmel, U. Rauen, U. Ravens., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
606. Microvascular reactivity in patients with hypercholesterolemia: the effect of lipid lowering treatment
- Creator:
- Tomáš Štulc, Zdislava Kasalová, Martin Prázný, Michal Vrablík, Jan Škrha, and Richard Češka
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, hypercholesterolémie, endoteliální dysfunkce, hypercholesterolemia, endothelial dysfunction, microcirculation, cholesterol lowering, laser-doppler, 14, and 612
- Language:
- English
- Description:
- Impaired NO-dependent vasodilation of resistance vessels is an early marker of an increased risk of atherosclerosis; utility of the examination of microcirculation, however, is far less established. We have therefore tested the hypothesis that hypercholesterolemia is associated with an impaired microvascular reactivity and that this defect is at least partially reversible by lipid-lowering treatment. Twenty-seven otherwise healthy patients with severe hypercholesterolemia (HLP) were examined at rest and then after 10 weeks of atorvastatin treatment (20 mg/day). Skin microvascular reactivity (MVR) was examined by laser-Doppler flowmetry. Baseline MVR values of the studied group were compared to healthy control subjects, HLP patients with coronary artery disease (CAD) and diabetic patients with and without diabetic retinopathy. MVR was normal in HLP subjects without CAD. On the contrary, MVR was impaired in HLP patients with CAD. There was no effect of atorvastatin on MVR, despite the profound reduction of serum lipids. MVR values did not correlate with cholesterol levels. In diabetic subjects, the MVR was substantially impaired only in patients with retinopathy. In the subjects without retinopathy, MVR was either normal (type I diabetes) or moderately impaired (type II diabetes). MVR was thus normal in HLP patients without manifest vascular disease and was not influenced by lipid lowering therapy. Impairment in the MVR was only evident in subjects with HLP and severe CAD. These results suggest that microcirculation is not involved in the early vascular dysfunction induced by HLP and that MVR rather reflects changes which appear later in the course of the atherosclerotic disease., T. Štulc, Z. Kasalová, M. Prázný, M. Vrablík, J. Škrha, R. Češka., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
607. Mild hypothermia attenuates changes in respiratory system mechanics and modifies cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation
- Creator:
- Dostál, P., Marian Šenkeřík, Radana Pařízková, Bareš, D., Pavel Živný, Helena Živná, and Černý, V.
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- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, záněty, cytokiny, podchlazení organismu, inflammations, cytokines, hypothermia, rats, mechanical ventilation, 14, and 612
- Language:
- English
- Description:
- Hypothermia was shown to attenuate ventilator-induced lung injury due to large tidal volumes. It is unclear if the protective effect of hypothermia is maintained under less injurious mechanical ventilation in animals without previous lung injury. Tracheostomized rats were randomly allocated to non-ventilated group (group C) or ventilated grou ps of normothermia (group N) and mild hypothermia (group H). After two hours of mechanical ventilation with inspiratory fraction of oxygen 1.0, respiratory rate 60 min-1 , tidal volume 10 ml·kg-1 , positive end-expiratory pressure (PEEP) 2 cm H 2 O or immediately after tracheostomy in non-ventilated animals inspiratory pressures were recorded, rats were sacrificed, pressure-volume (PV) curve of respiratory system constructed, bronchoalveolar lavage (BAL) fluid and aortic blood samples obtained. Group N animals exhibited a higher rise in peak inspiratory pressures in comparison to group H animals. Shift of the PV curve to right, higher total protein and interleukin- 6 levels in BAL fluid were observed in normothermia animals in comparison with hypothermia animals and non-ventilated controls. Tumor necrosis factor- α was lower in the hypothermia group in comparison with normothermia and non-ventilated groups. Mild hypothermia attenuated changes in respiratory system mechanics and modified cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation in animals without previous lung injury., P. Dostál, M. Šenkeřík, R. Pařízková, D. Bareš, P. Živný, H. Živná, V. Černý., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
608. Mismatch of Local Blood Flow and Oxidative Metabolism in Stunned Myocardium
- Creator:
- Schwanke, U., Heusch, G., and Schipke, J. D.
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- article, studie, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Myocardial stunning, Local blood flow, Local oxidative metabolism, Perfusion-metabolism mismatch, Heterogeneity, 14, and 612
- Language:
- English
- Description:
- Myocardial blood flow is spatially heterogeneous, reflecting non-uniform oxygen supply. Also, myocardial oxida-tive metabolism is spatially heterogeneous. The effects of acute ischemia and reperfusion on the rela-tionship between local myocardial blood flow (LMF) and oxi-dative metabolism are still unknown. LMF was measured in isolated, blood-perfused rabbit hearts using colored microspheres and oxidation water labeled with 18O2 (H218O). Three protocols were performed: 18O2-perfusion during normoxia (N; n=7), during early reperfusion (ER; 10 min, n=6), and late reperfusion (LR; 40 min, n=6) following 20 min no-flow ischemia. LMF and local H218O residues were determined within defined myocardial samples (105 ± 15 mg). For interindividual comparison, values were normalized to the mean of the individual experiment and expressed as percentages. LMF ranged from 18 to 193 % (N), 12 to 250 % (ER), and 11 to 180 % (LR). The H218O tissue residue ranged from 63 to 132 % (N), 73 to 142 % (ER) and 32 to 148 % (LR). The correlation between LMF and local oxidative metabolism during N (r=0.77; n=56) was lost in the postischemic heart during ER and LR. LMF during N and ER were only weakly correlated (r=0.24; n=48), whereas LMF during N and LR correlated well (r=0.87; n=48). It is concluded that the heterogeneous LMF pattern at baseline is maintained in the stunned myocardium whereas that of local oxidative metabolism is not. Apart from the established mechanisms underlying myocardial stunning, a mismatch between local flow and oxidative metabolism might also con-tribute., U. Schwanke, G. Heusch, J. D. Schipke., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
609. Mitochondrial adaptations in aged skeletal muscle: effect of exercise training
- Creator:
- Ziaaldini, M. M., Hosseini, S. R. A., and Fathi, M.
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- Subject:
- Fyziologie člověka a srovnávací fyziologie, stárnutí, tělesná cvičení, aging, exercises, mitochondrial dysfunction, 14, and 612
- Language:
- English
- Description:
- The aging process is associated with a decline in mitochondrial functions. Mitochondria dysfunction is involved in initiation and progression of many health problems including neuromuscular, metabolic and cardiovascular diseases. It is well known that endurance exercise improves mitochondrial function, especially in the elderly. However, recent studies have demonstrated that resistan ce training lead also to substantial increases in mitochondrial function in skeletal muscle. A comprehensive understanding of the cellular mechanisms involved in the skeletal muscle mitochondrial adaptations to exercise training in healthy elderly subjects, can help practitioners to design and prescribe more effective exercise trainings., M. M. Ziaaldini, S. R. A. Hosseini, M. Fathi., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
610. Mitochondrial Membrane Potential in Cardiac Myocytes
- Creator:
- Libor Škárka and Bohuslav Ošťádal
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- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Heart mitochondria, Membrane potential, Hypoxia, 14, and 612
- Language:
- English
- Description:
- Mitochondria are involved in cellular functions that transcend the traditional role of these organelles as the energy factory of the cell. Their relative inaccessibility and the difficulties involved in attempts to study them in their natural environment - the cytosol - has delayed much of this understanding and they still have many secrets to yield. One of the relatively new fields in this respect is undoubtedly the analysis of mitochondrial membrane potential. The realization that its alteration may have important pathophysiological consequences has led to an increased interest in measuring this variable in a variety of biological settings, including cardiovascular diseases. Measurements of mitochondrial membrane potential tell us much about the role of mitochondria in normal cell function and in processes leading to cell death. However, we must be aware of the limitations of using isolated mitochondria, single cells and different fluorescent indicators., L. Škárka, B. Ošťádal., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public