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22642. The Effects of Cardiopulmonary Bypass with Hollow Fiber Membrane Oxygenator on Blood Clotting Measured by Thromboelastography
- Creator:
- Michal Horáček and Karel Cvachovec
- Format:
- print, bez média, and svazek
- Type:
- article, studie, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Blood clot, Thromboelastography, Cardiopulmonary bypass, Bleeding, Oxygenator, 14, and 612
- Language:
- English
- Description:
- In cardiac surgical patients we investigated the effects of cardiopulmonary bypass (CPB) with a hollow fiber membrane oxygenator on blood clotting measured by thromboelastography (TEG). We found only a minimal change in the strength of blood clot described either by the TEG parameter MA (maximum amplitude) or by the shear modulus G calculated from MA. After CPB there was also a significant tendency towards hypercoagulation as defined by shortened parameters R, K and increased ?-angle. After comparison with published data obtained in cardiac surgical patients using a bubble oxygenator we conclude that currently used extracorporeal technology exerts a less negative influence on blood clotting than had been conceived previously., M. Horáček, K. Cvachovec., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
22643. The effects of head cooling on endurance and neuroendocrine responses to exercise in warm conditions
- Creator:
- Ansley, L., Marvin, G., Sharma, A., Kendall, M. J., Jones, D. A., and Bridge, M. W.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, hypertermie, tělesná cvičení, únava, physiology, hyperthermia, exercises, fatigue, prolactin, head cooling, 14, and 612
- Language:
- English
- Description:
- The present study investigated the effects of head cooling during endurance cycling on performance and the serotonergic neuroendocrine response to exercise in the heat. Subjects exercised at 75 % VO2max to volitional fatigue on a cycle ergometer at an ambient temperature of 29±1.0 °C, with a relative humidity of approximately 50 %. Head cooling resulted in a 51 % (p<0.01) improvement in exercise time to fatigue and Borg Scale ratings of perceived exertion were significantly lower throughout the exercise period with cooling (p<0.01). There were no indications of peripheral mechanisms of fatigue either with, or without, head cooling, indicating the importance of central mechanisms. Exercise in the heat caused the release of prolactin in response to the rise in rectal temperature. Head cooling largely abolished the prolactin response while having no effect on rectal temperature. Tympanic temperature and sinus skin temperature were reduced by head cooling and remained low throughout the exercise. It is suggested that there is a co-ordinated response to exercise involving thermoregulation, neuroendocrine secretion and behavioural adaptations that may originate in the hypothalamus or associated areas of the brain. Our results are consistent with the effects of head cooling being mediated by both direct cooling of the brain and modified cerebral artery blood flow, but an action of peripheral thermoreceptors cannot be excluded., L. Ansley, G. Marvin, A. Sharma, M. J. Kendall, D. A. Jones, M. W. Bridge., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
22644. The effects of hyperoxia, hypoxia, and ischemia/reperfusion on the activity of cytochrome oxidase from the rat retina
- Creator:
- Šišková, A. and Jiří Wilhelm
- Format:
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, sítnice, hypoxie, hyperoxie, ischemie, retina, hypoxia, hyperoxia, ischemia, cytochrome oxidase, lipid peroxidation, 14, and 612
- Language:
- English
- Description:
- Cytochrome oxidase activity from the retina can be enhanced or depressed by free radical-mediated reactions both in positive and negative aspect. The greatest effect was exerted by ischemia/reperfusion, which significantly increased the fluorescent products of lipid peroxidation (358 %, P<0.01) and inhibited the enzyme activity (14 %, P<0.001). After hyperoxia the fluorescent products slightly increased (192 %, P< 0.05) as well as the enzyme activity (133 %, P<0.05). Hypoxia had no effect on any of these parameters. Specific changes in the composition of fluorophores after ischemia/reperfusion were revealed in the fluorescence spectra. The fact that increased lipid peroxidation after hyperoxia and after ischemia/reperfusion does not produce the same effect upon cytochrome oxidase activity might be explained by changes in the kinetic behavior of cytochrome oxidase. In the control enzyme preparation, two binding sites for cytochrome c were observed. One was of the low-affinity (Km=60 mM) and the other of the high-affinity (Km=1.12 mM). After in vitro-initiated lipid peroxidation, the low-affinity binding site was lost and the activity measured under "optimum" conditions at a single cytochrome concentration was higher than in the controls. This implies that oxidative damage to cytochrome oxidase in vivo can be site-specific and its extent should be estimated by performing detailed kinetic analysis as otherwise the results might be misleading., A. Šišková, J. Wilhelm., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
22645. The effects of lead on photosynthetic performance of waxberry seedlings (Myrica rubra)
- Creator:
- He, B., Gu, M., Wang, X., and He, X.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, chlorophyll fluorescence, lead stress, 2, and 581
- Language:
- Multiple languages
- Description:
- The photosynthesis was investigated 30 d after Pb treatment in Myrica rubra seedlings. The Pb treatment resulted in significantly increased Pb concentrations in shoots. Low Pb concentration exposure (≤2 mM) reduced the net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance (gs) without affecting the intercellular CO2 concentration (Ci), chlorophyll (Chl) content, and Chl fluorescence parameters. At 10 d after severe Pb treatment (≥4 mM), PN was inhibited and accompanied by Chl damage, while at 30 d, the inhibition of PN was followed by an increase of Ci and a decrease of gs, E, Chl content, and Chl fluorescence parameters. M. rubra showed a promising prospect for use in the soil phytoremediation, when Pb concentration is low, but the remediation efficiency of M. rubra is limited if Pb exceeds 2 mM., B. He, M. Gu, X. Wang, X. He., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
22646. The effects of lidocaine on bupivacaine-induced cardiotoxicity in the isolated rat heart
- Creator:
- Ivo Křikava, Jiří Jarkovský, Pavel Štourač, Marie Nováková, and Pavel Ševčík
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, bupivacaine, lidocaine, isolated rat heart, cardiotoxicity, QRS duration, 14, and 612
- Language:
- English
- Description:
- Bupivacaine is a widely used long-acting local anaesthetic. In clinical practice, a mixture of bupivacaine and lidocaine is often used in order to combine the faster onset of sensory blockade of lidocaine with more profound and longer duration of blockade by bupivacaine. The aim of this study was to compare the cardiotoxicity of large doses of bupivacaine and mixture of bupivacaine with lidocaine in the isolated rat heart and to estimate whether or not the addition of lidocaine in clinically relevant concentration increases bupivacaine-induced toxicity. Experiments were performed on 21 adult male rats divided into three groups: B (6 μg/ml bupivacaine), BL (6 μg/ml bupivacaine and 12 μg/ml lidocaine) and L (12 μg/ml lidocaine). The experiment consisted of three 30 min periods: stabilisation, perfusion and washout. The isolated hearts were perfused according to Langendorff with Krebs-Henseleit solution at constant pressure (80 mmHg) and 37 °C (CaCl2 1.25 mM) and the heart rate (based on RR interval assessment), PQ and QRS intervals were measured. The present study shows that the mixture of tested anaesthetics - bupivacaine and lidocaine - impairs the intraventricular conduction parameters (QRS interval prolongation) to a lesser extent than bupivacaine itself, and that this effect is marked mainly at the beginning of perfusion., I. Křikava ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
22647. The effects of para-hydroxybenzoic acid treatment on photosynthetic parameters of Populus × euramericana "Neva"
- Creator:
- Liang, G. T., Zhang, S. Y., Guo, J., Yang, R., Li, H., Fang, X. C., and Zhang, G. C.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- topol, poplar, chlorofylová fluorescence, výměna plynu, alelopatie rostlin, chlorophyll fluorescence, cropping obstacle, gas exchange, plant allelopathy, para-hydroxybenzoic acid, 2, and 581
- Language:
- Multiple languages
- Description:
- As a common tree species in northern China, Populus × euramericana "Neva" has an important practical value for the study of continuous cropping obstacles in poplar cultivation. Plant allelopathy is the main reason for continuous cropping obstacles, which are caused by allelochemicals, such as para-hydroxybenzoic acid (p-HB). The objective of this study was to investigate the effects of p-HB on the photosynthesis of poplar. Photosynthetic parameters of Populus × euramericana "Neva" poplar were determined in a pot culture experiment where five p-HB concentrations were used (0, 1, 2, 4, and 6 mmol L−1). Each seedling was treated with 4 L of p-HB solution every seven days, ten times in total. p-HB inhibited the photosynthesis of poplar significantly, as shown by a clear decline in the net photosynthetic rate. Our results indicated nonstomatal limitation responsible for the photosynthesis reduction., G. T. Liang, S. Y. Zhang, J. Guo, R. Yang, H. Li, X. C. Fang, G. C. Zhang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
22648. The effects of pertussis toxin-treatment on integrated vasoactive response of vascular system in spontaneously hypertensive rats
- Creator:
- Soňa Čačányiová, Kristek, F., Jaroslav Kuneš, and Josef Zicha
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, krevní tlak, acetylcholin, physiology, blood pressure, acetylcholine, spontaneously hypertensive rats (SHR), pertussis toxin, noradrenaline, bradykinin, vasoactive responses, 14, and 612
- Language:
- English
- Description:
- We investigated the effect of pertussis toxin (PTX) on hypotensive response induced by acetylcholine (ACh) and bradykinin (BK) and on noradrenaline (NA)-induced pressor response in spontaneously hypertensive rats (SHR). Fifteen-week-old Wistar rats and age-matched SHR were used. Half of SHR received PTX (10 μg/kg/i.v.) and the experiments were performed 48 h later. After the anesthesia the right carotid artery was cannulated in order to record blood pressure (BP). The hypotensive response to ACh was enhanced in SHR compared to Wistar rats. After pretreatment of SHR with PTX the hypotensive response to ACh was reduced compared to untreated SHR and it was also diminished in comparison to Wistar rats. Similarly, the hypotensive response to BK was also decreased after PTX pretreatment. The pressor response to NA was increased in SHR compared to Wistar rats. NA-induced pressor response was considerably decreased after PTX pretreatment compared to untreated SHR. In conclusion, the enhancement of hypotensive and pressor responses in SHR was abolished after PTX pretreatment. Our results suggested that the activation of PTX-sensitive inhibitory Gi proteins is involved in the regulation of integrated vasoactive responses in SHR and PTX pretreatment could be effectively used for modification of BP regulation in this type of experimental hypertension., S. Čačányiová, F. Kristek, J. Kuneš, J. Zicha., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
22649. The effects of phenolic acids on the photosynthetic characteristics and growth of Populus x euramericana cv. 'Neva' seedlings
- Creator:
- Xie, D. F., Zhang, G. C., Xia, X. X., Lang, Y., and Zhang, S. Y.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, allelochemical, chlorophyll fluorescence, CO2 assimilative capacity, light response, light-use efficiency, reactive oxygen species, 2, and 581
- Language:
- Multiple languages
- Description:
- Populus x euramericana cv. ‘Neva’ is an important tree species in northern China. In the study, we used its potted oneyear- old seedlings as experimental material and established three treatments (CK, 0.5X, and 1.0X) according to the concentrations of phenolic acids in order to examine the effects of different concentrations on the photosynthetic characteristics and growth of poplar. With increasing concentrations of phenolic acids, the net photosynthetic rate, stomatal limitation, transpiration rate, apparent quantum yield, photochemical quenching coefficient, electron transport rate, chlorophyll content, and total biomass decreased significantly. The intercellular CO2 concentration, light-compensation point, nonphotochemical quenching, malondialdehyde content, and root/shoot ratio increased significantly. Peroxidase and superoxide dismutase activities initially decreased and then increased. We concluded that phenolic acids significantly inhibited poplar’s photosynthesis and the higher phenolic acid concentration, the greater inhibition of photosynthesis occurred. This inhibition effect was mainly caused by nonstomatal factors. Phenolic acids induced noticeable photoinhibition, resulted in the irreversible damage of membrane structure, and then changed intracellular metabolic processes. To cope with phenolic acid stress, poplar seedlings increased dissipation of excess light energy and distributed relatively more biomass to underground parts within carbon allocation., D. F. Xie, G. C. Zhang, X. X. Xia, Y. Lang, S. Y. Zhang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
22650. The effects of short-term norepinephrine up-titration on hemodynamics in cardiogenic shock
- Creator:
- Richard Rokyta, Jitka Tesařová, Vratislav Pechman, Petr Gajdoš, and Aleš Kroužecký
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, šok (lékařství), hemodynamika, tlak, shock (medicine), hemodynamics, pressure, norepinephrine, cardiac function, 14, and 612
- Language:
- English
- Description:
- A higher mean arterial pressure (MAP) achieved by norepinephrine up-titration may improve organ blood flow in critically ill, whereas norepinephrine-induced afterload rise might worsen myocardial function. Our aim was to assess the effects of norepinephrine dose titration on global hemodynamics in cardiogenic shock. We prospectively evaluated 12 mechanically ventilated euvolemic patients (aged 67±12 years) in cardiogenic shock (10 patients acute myocardial infarction, 1 patient dilated cardiomyopathy, 1 patient decompensated aortic stenosis). Hemodynamic monitoring included arterial and Swan-Ganz catheters. The first data were obtained at MAP of 65 mm Hg, then the norepinephrine dose was increased over 40 min to achieve MAP of 85 mm Hg. Finally, the norepinephrine-dose was tapered over 40 min to achieve MAP of 65 mm Hg. Norepinephrine up-titration increased MAP to the predefined values in all patients with concomitant mild increase in filling pressures and heart rate. Systemic vascular resistance increased, whereas cardiac output remained unchanged. During norepinephrine down-titration, all hemodynamic parameters returned to baseline values. We observed no changes in lactate levels and mixed venous oxygen saturation. Our data suggest that short-term norepinephrine dose up-titration in cardiogenic shock patients treated or pretreated with inotropes was tolerated well by the diseased heart., R. Rokyta, Jr ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public