Functional magnetic resonance imaging (fMRI) was used to demonstrate the brain activation during transition from unconscious to conscious breathing in seven healthy human subjects. In right-handed volunteers, the activated areas were found in both hemispheres. The medial part of the precentral gyrus (area 4) was constantly activated in the left hemisphere. Additional activated areas were demonstrated in the premotor cortex and in the posterior parietal cortex. The activated cortical sites exhibited analogous distribution in the right hemisphere. In two out of the seven subjects, activated sites were also observed in the cerebellar hemispheres, and in the lentiform and caudate nuclei., V. Šmejkal, R. Druga, J. Tintěra., and Obsahuje bibliografii
This study extends our previous work by examining the effects of alpha2 -adrenoceptors under cold stimulation involving the increase of myogenic vascular oscillations as increases of very-low-frequency and low-frequency of the blood pressure variab ility. Forty-eight adult male Sprague-Dawley rats were randomly divided into four groups: vehicle; yohimbine; hexamethonium+yohimbine; guanethidine+yohimbine. Systolic blood pressure, heart rate, power spectral analysis of spontaneous blood pressure and he art rate variability and spectral coherence at very-low-frequency (0.02 to 0.2 Hz), low-frequency (0.2 to 0.6 Hz), and high-frequency (0.6 to 3.0 Hz) regions were monitored using telemetry. Key findings are as follows: 1) Cooling-induced pressor response was attenuated by yohimbine and further attenuated by hexamethonium+yohimbine and guanethidine+yohimbine, 2) Cooling-induced tachycardia response of yohimbine was attenuated by hexame - thonium+yohimbine and guanethidine+yohimbine, 3) Different patterns of p ower spectrum reaction and coherence value compared hexamethonium+yohimbine and guanethi-dine+yohimbine to yohimbine alone under cold stimulation. The results suggest that sympathetic activation of the postsynaptic alpha2-adrenoceptors causes vasoconstriction and heightening myogenic vascular oscillations, in turn, may increase blood flow to prevent tissue damage under stressful cooling challenge., Y.-H. Lin, Y.-P. Liu, Y.-C. Lin, P.-L. Lee, C.-S. Tung., and Obsahuje bibliografii
The goal of this study is to summarize the current knowledge on the effects of one of the essential metals, copper (Cu) on the reproductive system. The development of past four decades addressing effects of Cu on reproductive organs is reviewed. The most relevant data obtained from in vivo and in vitro experiments performed on humans and other mammals, including effects of copper nanoparticles (CuNPs) on the reproductive functions are presented. Short term Cu admi nistration has been found to exert deleterious effect on intracellular organelles of rat ovarian cells in vivo . In vitro administration in porcine ovarian granulosa cells releases insulin-like growth factor (IGF-I), steroid hormone progesterone (P4), and induces expression of peptides related to proliferation and apoptosis. Adverse effect of Cu on male reproductive functions has been indicated by the decrease in spermatozoa parameters such as concentration, viability and motility. Copper nanoparticles are capable of generating oxidative stress in vitro thereby leading to reproductive toxicity. Toxic effect of CuNPs has been evident more in male mice than in females. Even though further investigations are necessary to arrive at a definitive conclusion, Cu notably influences the reproductive functions by interfering with both male and female reproductive systems and also hampers embryo development in dose-dependent manner., S. Roychoudhury, S. Nath, P. Massanyi, R. Stawarz, M. Kacaniova, A. Kolesarova., and Obsahuje bibliografii
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