Spatiotemporal dynamics of event-related potentials (ERP) evoked by non-target stimuli in a visual oddball experiment and the presence of coherent oscillations in beta 2 frequency band of decomposed EEG records from peristimulus period were investigated by means of intracranial electrodes in humans. Twenty-one patients with medically intractable epilepsy participated in the study. The EEG signal was recorded using platinum electrodes implanted in several cortical and subcortical sites. Averaged 2 s EEG records were analyzed. Task-specific EEG changes were found in each patient, ERPs were derived from 92 electrodes used (96 % of possible cases). In the majority of analysed cases, ERPs were composed of several distinct components, and their duration was mostly longer than 1 s. The mean onset of the first ERP component was 158±132 ms after the stimulus (median 112 ms, minimum value 42 ms, maximum value 755 ms), and large variability of these onset times was found in all the investigated structures. Possible coherence between neural activities of remote brain sites was investigated by calculating running correlations between pairs of decomposed EEG records (alpha, beta 1, beta 2 frequency bands were used, total number of correlated pairs was 662 in each frequency band). The record pairs exhibiting highly correlated time segments represented 23 % of all the investigated pairs in alpha band, 7 % in beta 1 band, and 59 % in beta 2 band. In investigated 2 s record windows, such segments were distributed evenly, i.e. they were also found before the stimulus onset. In conclusion, the results have implicated the idea that a lot of recorded ERPs was more or less by-products of chance in spreading a signal within the neuronal network, and that their functional relevance was somewhat linked with the phenomenon of activity synchronization., M. Kukleta ... [et al.]., and Obsahuje seznam literatury
The objective of our study was to compare Doppler echocardiography imaging with pu lmonary artery thermodilution measurement during mechanical ventilation. Total 78 piglets (6 weeks old, average weight 24 kg, under general anesthesia) were divided into 4 groups under different cardiac loading conditions (at rest, with increased left ventricular afterload, with increased right ventricular preload, and with increased afterload of both heart ventricles). At 60 and 120 min the animals were examined by echocardiography and simultaneously pulmonary artery thermodilution was used to measure cardiac output. Tei-indexes data were compared with invasively monitored hemodynamic data and cardiac output values together with calculated vascular resistance indices. A total of 224 parallel measurements were obtained. Correlation was found between values of right Tei-index of my ocardial performa nce and changes in right ventricular preload (p<0.05) and afterload (p<0.01). Significant correlation was also found between left index values and changes of left ventricular preload (p<0.001), afterload (p<0.001), stroke volume (p<0.01), and cardiac output (p<0.01). In conclusion, echocardiographic examination and determination of the global performance selectively for the right and left ventricle can be recommended as a suitable non-invasive supplement to the whole set of methods used for monitoring of circulation and cardiac performance., J. Kobr ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
We developed a new method for the quantitative determination of myosin heavy chain (MyHC) isoforms taking advantage of immunochemical differences and based on the ELISA principle. In the present paper we compare anal ysis of MyHC isoforms using the SDS-PAGE and the ELISA methods in the same samples of adult female inbred Lewis strain euthyroid, hyperthyroid and hypothyroid rats. In all thyroid states, the same composition and corresponding changes of MyHC isoforms were determined using both methodological approaches in the slow soleus and the fast extensor digitorum longus muscles. Our results showed that ELISA can be used for a “semi-quantitative” or “comparative” measurement of MyHC isoforms in multiple muscle samples, but that it is neither more exact no r faster compared to SDS-PAGE., Jan Říčný., and Obsahuje bibliografii a bibliografické odkazy
The purpose of the present study was to examine whether the level of oxygen uptake (V.o2) at the onset of decrement-load exercise (DLE) is lower than that at the onset of constant-load exercise (CLE), since power output, which is the target of V.o2 response, is decreased in DLE. CLE and DLE were performed under the conditions of moderate and heavy exercise intensities. Before and after these main exercises, previous exercise and post exercise were performed at 20 watts. DEL was started at the same power output as that for CLE and power output was decreased at a rate of 15 watts per min. V.o2 in moderate CLE increased at a fast rate and showed a steady state, while V.o2 in moderate DLE increased and decreased linearly. V.o2 at the increasing phase in DLE was at the same level as that in moderate CLE. V.o2 immediately after moderate DLE was higher than that in the previous exercise by 98±77.5 ml/min. V.o2 in heavy CLE increased rapidly at first and then slowly increased, while V.o2 in heavy DLE increased rapidly, showing a temporal convexity change, and decreased linearly. V.o2 at the increasing phase of heavy DLE was the same level as that in heavy CLE. V.o2 immediately after heavy DLE was significantly higher than that in the previous exercise by 156±131.8 ml/min. Thus, despite the different modes of exercise, V.o2 at the increasing phase in DLE was at the same level as that in CLE due to the effect of the oxygen debt expressed by the higher level of V.o2 at the end of DLE than that in the previous exercise., T. Yano, H. Ogata, R. Matsuura, T. Arimitsu, T. Yunoki., and Obsahuje bibliografii a bibliografické odkazy
This study investigated whether each part of the heart is evenly innervated by the left or right vagus and observed the mechanism of compensatory recovery after unilateral cervical vagotomy. HR, BP, LVSP and ±dp/dt max all decreased one week after left vagotomy, whereas only BP and -dp/dt max decreased one week after right vagotomy. We stern blot analyses revealed that the expression of M2 receptors in the left atrium and left ventricle was upregulated after subacute (1 week) left/right vagotomy. However, significantly more cholinesterase-positive nerves in LV and RV were seen one week after unilateral vagotomy compared to the sham-operated group. In addition, baroreflex sensitivity was increased after subacute right vagotomy. The decreasing effects of ACh (0.5 μ g/kg) on LVSP and ±dp/dt max (but not on HR and BP) were facilitated by subacute unilateral vagotomy. Our present experiments indicate that 1) the working myocardium is innervated bilaterally by the vagus, 2) ventricular contractility is influenced more by denervation of the left than the right vagus and 3) up-regulation of M2 muscarinic receptors in the left heart, increase of cholinergic nerves, and high baroreflex sensitivity could be involved in the mechanism of compensatory hemodynamic recovery via contralateral vagus overactivity, thereby amplifying contralateral vagal activity and decreasing cardiac contractility., L. N. Chen, W. J. Zang, X. J. Yu, J. Liu, D. L. Li, S. S. Kong, J. Lu, X. L. Xu., and Obsahuje bibliografii a bibliografické odkazy
E. Filová, M. Rampichová, M. Handl, A. Lytvynets, R. Halouzka, D. Usvald, J. Hlučilová, R. Procházka, M. Dezortová, E. Rolencová, E. Košťáková, T. Trč, E. Šťastný, L. Koláčná, M. Hájek, J. Motlík, E. Amler. 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
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
The aim of this study was to investigate the concentrations of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), leptin, tumor necrosis factor-α, interleukin (IL)-1β and IL-6, in cycles with a premature rise of serum progesterone. 25 intracytoplasmic sperm injection (ICSI) cycles with (Group 1) and 25 ICSI cycles without a premature progesterone elevation (Group 2) were included. The cut-off value of serum progesterone on the day of human chorionic gonadotropin (hCG) administration was 0.9 ng/ml. The indication for ICSI was male factor infertility exclusively. On the day of hCG injection, serum IL-6, VEGF and bFGF were significantly higher in Group 1 (7.7±24.5 pg/ml, 290.2±161.4 pg/ml and 15.7±8.2 ng/ml respectively) than in Group 2 (1.7±0.7 pg/ml, 175.2±92.1 pg/ml, and 9±1.6 ng/ml respectively). On the day of follicular puncture, serum cytokine concentrations were similar in the two groups. IL-6 intrafollicular concentrations were higher in Group 1 (14.7±20.7 pg/ml) than in Group 2 (9±9.3 pg/ml, p=0.031). There were no differences regarding the ICSI outcome. Patients with serum progesterone above 0.9 ng/ml, have elevated serum concentrations of IL-6, VEGF, and bFGF, as well as elevated intrafollicular concentrations of IL-6. The outcome of ICSI cycles is not associated with premature elevation of progesterone when the cut-off value is set at 0.9 ng/ml., N. Nikolettos, B. Asimakopoulos, F. Köster, B. Schöpper, Ch. Schulz, G. S. Caglar, A. Efthimiadou, O. Pagonopoulou, K. Diedrich, S. Al-Hasani., and Obsahuje bibliografii a bibliografické odkazy
This study was designed to measure nitrite/nitrate and cytokine levels of serum obtained from septic shock patients and to describe potential depressant effects of human septic serum on rat cardiomyocytes. Serum was prepared from 10 non-septic patients and 10 patients with documented septic shock. Adult rat ventricular myocytes were exposed to 20 % serum in the medium. Cardiomyocyte contractility was assessed by measuring shortening fraction and shortening velocity. Serum levels of nitrite/nitrate, a marker of nitric oxide final metabolites, and cytokines (tumor necrosis factor (TNF)-α, interleukin (IL) 1β , 6, 10, 8 and 12p70) were measured. Compared with serum from non-septic patients, serum of septic shock patients induced rapid reduction of the extent and velocity of shortening in isolated cardiomyocytes. Nitrite/nitrate, TNF-α , IL-1β and IL-12p70 concentrations of tested serum for cardiomyocyte studies were not increased in septic serum compared with controls . In contrast, septic serum that induced a depression of in vitro contractility, had increased levels of IL-6, IL-8 and IL-10. We can conclude that the depression of in vitro contractility induced by septic serum is not directly dependent on elevated levels of nitric oxide metabolites, TNF-α or IL-1β. Our results support the view that other cytokines, including IL-6, IL-8 and IL-10, are potent circulating mediators of myocardial depression in cardiomyocytes., O. Joulin, P. Petillot, M. Labalette, S. Lancel, R. Neviere., and Obsahuje bibliografii a bibliografické odkazy