The aim of this study was to find the principal parameters of surface tension of the blood and verify its possible correlation with some of the commonly assessed laboratory indicators that are affected by diseases with the expected possible changes in the surface tension of the blood. The surface tension of the blood was assessed in 150 patients. At the same time, the basic biochemical and hematological parameters were determined in these patients. The results have shown a close correlation between the surface blood tension and the activity of plasma gamma-glutamyltransferase. We assume that this relationship is based on the changes in concentration of bile acids in the blood during liver or bile duct afflictions., A. Kratochvíl, E. Hrnčíř., and Obsahuje bibliografii
Plasma carnitine levels were measured in two alternative nutrition groups - strict vegetarians (vegans) and lactoovovegetarians (vegetarians consuming limited amounts of animal products such as milk products and eggs). The results were compared to an average sample of probands on mixed nutrition (omnivores). Carnitine levels were correlated with the intake of essential amino acids, methionine and lysine (as substrates of its endogenous synthesis), since the intake of carnitine in food is negligible in the alternative nutrition groups (the highest carnitine content is in meat, lower is in milk products, while fruit, cereals and vegetables contain low or no carnitine at all). An average carnitine level in vegans was significantly reduced with hypocarnitinemia present in 52.9 % of probands. Similarly, the intake of methionine and lysine was significantly lower in this group due to the exclusive consumption of plant proteins with reduced content of these amino acids. Carnitine level in lactoovovegetarians was also significantly reduced, but the incidence of values below 30 m mol/l was lower than in vegans representing 17.8 % vs. 3.3 % in omnivores. Intake of methionine and lysine was also significantly reduced in this group, but still higher compared to vegans (73 % of protein intake covered by plant proteins). Significant positive correlation of carnitine levels with methionine and lysine intake in alternative nutrition groups indicates that a significant portion of carnitine requirement is covered by endogenous synthesis. Approximately two thirds of carnitine requirement in omnivores comes from exogenous sources. The results demonstrate the risks of alternative nutrition with respect to the intake of essential amino acids, methionine and lysine, and with respect to the intake and biosynthesis of carnitine., M. Krajčovičová-Kudláčková, R. Šimončič, A. Béderová, K. Babinská, I. Béder., and Obsahuje bibliografii
Insulin resistance associated with dyslipidemia enhances cardiovascular risk. Several atherogenic indexes have been suggested to give more precise information about the risk. The aim of our study was to estimate, which atherogenic index correlates better with parameters of insulin resistance. Furthermore, we compared the parameters of lipid metabolism and insulin resistance between smokers and non-smokers. In our cross-sectional study we enrolled 729 patients with dyslipidemia which were divided into two groups - non-smokers (586) and smokers (143). We measured lipid profile, parameters of insulin resistance (fasting glycemia, insulin, HOMA-IR, C-peptide, proinsulin) and calculated atherogenic indexes - atherogenic index of plasma (log (TAG/HDL-C), AIP), ApoB/ApoA1 index and nonHDL-C. AIP was found out to show stronger correlations with parameters of insulin resistance (p<0.001, correlation coefficients ranging between 0.457 and 0.243) than other indexes (ApoB/ApoA1 or nonHDL cholesterol). AIP correlated with parameters of insulin resistance both in smokers and nonsmokers, but after adjustment (for age, body mass index, waist circumference) persisting only in non-smokers. Smokers had a wider waist circumference and a proatherogenic lipid profile. Smoking increases the risk of developing metabolic syndrome. AIP can be used in daily praxis for predicting insulin resistance in patients with dyslipidemia, predominantly in non-smokers., L'. Cibičková, D. Karásek, K. Langová, H. Vaverková, J. Orság, J. Lukeš, D. Novotný., and Obsahuje bibliografii
The aim of this study was to evaluate myofibrillar creatine kinase (EC 2.7.3.2) activity on the background of the effect of substrate channeling by myosin ATPase and to compare it with creatine kinase (CK) activity of whole skinned fibers. In order to assess CK activity, skinned fibers were prepared from the rat psoas major muscles defined by light microscopy. The activity in permeabilized fibers after treatment with saponin, Triton X-100 and Ca2+-free medium reached 2.80, 6.97 and 3.32 m mol ATP min-1 mg-1 protein, respectively, when a coupled enzyme assay system with external hexokinase and glucose-6-phosphate dehydrogenase was used. Transmission electron microscopy (TEM) revealed a possible interference among activities of sarcolemmal, sarcoplasmic, myofibrillar and mitochondrial CK from persisting structures. For evaluation of the myofibrillar CK itself, a pure myofibrillar fraction was prepared. Fraction purity was confirmed by TEM and by enzymatic assays for marker enzymes. Two procedures, i.e. the coupled enzyme assay and the evaluation of phosphocreatine (Pcr) concentration before and after the CK reaction, were used for measurement of CK activity in this fraction. The procedures resulted in 3.2 nmol ATP min-1 mg-1 protein and 7.6 nmol PCr min-1 mg-1 protein, respectively. These alternative approaches revealed a discrepancy between the reacting portions of Pcr by more than 50 % , which provides information about the size of the effect, generally described as substrate channeling., M. Gregor, J. Mejsnar, A. Janovská, J. Žurmanová, O. Benada, B. Mejsnarová., and Obsahuje bibliografii
In this work, we evaluated the effect of adaptation to heat on the fall of blood pressure (BP) induced by heat shock (HS) and the interrelation between nitric oxide (NO) and heat shock protein, HSP70. Experiments were carried out on Wistar rats. It was shown that HS resulted in a generalized and transient increase in NO production (the electron paramagnetic resonance method) and a fall of BP from 113± 3 to 88± 1 mm Hg (?<0.05). Adaptation to heat itself did not affect BP, but completely prevented the NO overproduction and hypotension induced by HS. The adaptation simultaneously increased the brain NO-synthase content and induced HSP70 synthesis (the Western blot analysis) in various organs. Both the antihypotensive effects of adaptation and HSP70 accumulation were completely prevented by L-NNA, an inhibitor of NO synthesis, or quercetin, an inhibitor of HSP70 synthesis. The data suggest that adaptation to heat stimulates NO synthesis and NO activates synthesis of HSP70. HSP70, which hampers NO overproduction, thus restricts the BP fall induced by heat shock., I. Yu. Malyshev, L.A. Bayda, A.I. Trifonov, N.P. Larionov, L.D. Kubrina, V.D. Mikoyan, A.F. Vanin, E.B. Manukhina., and Obsahuje bibliografii
The aim of this study was to determine the effect of chronic crowding on the cardiovascular system of Wistar-Kyoto (WKY) rats. Rats were randomly divided into the control (480 cm2 per rat) or crowded (200 cm2 per rat) group for eight weeks. Body weight, blood pressure (BP), heart rate and plasma nitrate/nitrite levels of the crowded rats were not different from controls at the end of the experiment. Plasma corticosterone exhibited an increasing trend (5.7±1.8 vs. 12.6±3.7 ng/ml, p=0.08) while blood glucose was significantly reduced in the crowded rats in comparison with the controls. Nitric oxide (NO) synthase activity and nitrate/nitrite levels of the crowded rats were significantly elevated in the aorta by ∼80 % and ∼20 %, respectively, but unchanged in the left ventricle. Moreover, acetylcholine-induced relaxation was significantly increased in the crowded rats in both the femoral artery (61±5 % vs. 76±5 %, p<0.001) and mesenteric artery (51±6 % vs. 72±7 %, p<0.001). In conclusion, results suggest that chronic crowding may increase vasorelaxation and vascular NO production in normotensive rats. This may be considered as an adapting mechanism preventing the development of the stress-related elevation of BP. Additionally, results also suggest caution in the housing of rats because an inappropriate crowding may affect results of the experiment significantly., I. Bernátová, A. Púzserová, J. Navarová, Z. Csizmadiová, M. Zeman., and Obsahuje bibliografii a bibliografické odkazy
Each artery conduces blood (conduit function, CF) and smoothes out the pulsatility (buffering function, BF), while keeping its wall protected against the high oscillations of the pulse waves (damping function, ξ). These functions depend on each segment viscoelasticity and capability to store and dissipate energy. When a graft/prosthesis is implanted, the physiological gradual transition in the viscoelasticity and functionality of adjacent arterial segments is disrupted. It remains to be elucidated if the cryografts would allow keeping the physiological biomechanical transition. The aim of this study was to evaluate the cryografts capability to reproduce the functional, energetic and reflection properties of patients’ arteries and fresh homografts. Common carotid’s pressure, diameter and wall-thickness were recorded in vivo (15 patients) and in vitro (15 cryografts and 15 fresh homografts from donors). Calculus: elastic (Epd) and viscous (Vpd) indexes, CF, BF, dissipated (WD) and stored (WPS) energy and ξ. The graft-patient’s artery matching was evaluated using the reflection coefficient (Γ) and reflected power (WΓ). Cryografts did not show differences in Epd, Vpd, BF, CF, WD, WPS, and ξ, in respect to fresh homografts and patients’ arteries, ensuring a reduced Γ and WΓ. Cryografts could be considered as alternatives in arterial reconstructions since they ensure the gradual transition of patients’ arteries biomechanical and functional behavior., D. Bia, J. G. Barra, R. L. Armentano, Y. Zócalo, H. Pérez, M. Saldíaz, I. Álvarez, E. I. Cabrera Fischer., and Obsahuje bibliografii a bibliografické odkazy
In our previous experiments we demonstrated that osmotic opening of the blood brain barrier (BBB) in rats by administration of mannitol into the internal carotid artery leads to cerebral edema. The aim of this study was to confirm objectively the development of brain edema and determine whether it affects spontaneous locomotor activity in rats (SLA). Brain edema was verified by computer tomography (CT) examination of the brain and SLA was observed during open field test. Twenty four adult male rats were divided into four groups of six: (1) control animals (C), (2) controls with anesthesia (CA), (3) controls with sham surgery (CS), (4) experimental - osmotic opening of the BBB (MA). Osmotic BBB disruption manifested by reducing the density of brain tissue (hypodensity), suggesting a higher water content in the brain tissue. SLA was compared between C, CA, CS and MA groups and between MA and CA groups. Significant difference was found only between the control group and MA group. In the first 30 min of the examination, rats after the mannitol administration revealed a marked limitation of spontaneous locomotor activity. Experimental results demonstrated reduction of spontaneous locomotor activity in rats with induced brain edema., P. Kozler, V. Riljak, K. Jandová, J. Pokorný., and Obsahuje bibliografii
At frog neuromuscular junction, noradrenaline (NA) shortens the release period for evoked quantal release acting on a b 1 receptor. To test the hypothesis that this action of NA is mediated by cAMP, we measured the latencies of focally recorded uni-quantal endplate currents (EPCs) after application of dibutyryl-cAMP (db-cAMP) and adenylyl cyclase activator, forskolin. The interval between the time when responses with minimal delay appeared and the point at which 90 % of all latencies had occurred (P90 parameter) was shortened in the presence of both 1x10-6 mol/l db-cAMP and 1x10-6 mol/l forskolin by about 30 %. The cAMP-induced shortening is equal to that found after application of NA and effects of both drugs are not additive., E. Bukcharaeva, D. Samigullin, E. E. Nikolsky, F. Vyskočil., and Obsahuje bibliografii
Within the framework of our studies on hypertension in various rat strains, we have examined the effect of cyclosporin A (CsA) on intracellular calcium signaling under conditions of oxidative stress. For these preliminary experiments, we have chosen isolated hepatocytes of normotensive rats as a model system for the study of the role of intracellular calcium. We used tert-butyl hydroperoxide (t-BHP, 1 mmol.l-1) as an prooxidant agent. When compared to the controls, we found increased levels of cytosolic free calcium concentration (Ca2+i) during 120 min incubation. The preincubation of hepatocytes with CsA in the concentration of 0.5 m mol.l-1 did not change the physiological level of cytosolic calcium. However, a dual action of CsA on elevated Ca2+i was observed during oxidative injury of hepatocytes: while in the first period of incubation CsA increased Ca2+i, CsA reduced the effect of t-BHP on Ca2+i during the next period of incubation. This indicates the ability of CsA to modify oxidative stress, but further studies are necessary to explain these findings., E. Kmoníčková, L. Kameníková, S. Hynie, H. Farghali., and Obsahuje bibliografii