Although cycle length (CL) constitutes a fundamental descriptor of any arrhythmia, there is not larger study describing mean CL in electrophysiologically confirmed cavo-tricuspid isthmus (CTI)- dependent atrial flutter (AFL). We analyzed retrospectively digital recordings of 121 patients (98 men; age 64±11 years) referred for radiofrequency ablation of persistent CTI-dependent AFL. Median of mean AFL CL was 240 ms (interquartile range (IQR) of 222-258 ms, overall range of 178-399 ms). The distribution of CL was not normal (Shapiro Wilk test, p<0.001). Both counterclockwise and clockwise (14.9 % of all cases) AFLs were comparable in their CL; 240 (IQR 222-258) ms vs. 234 (217-253) ms, respectively. AFL CL<200 ms and AFL CL<190 ms was noticed in 5 (4.1 %) and 3 cases (2.5 %), respectively. In multivariate regression analysis, age (increase by 6±3 ms per decade of age, p=0.036), treatment with specific antiarrhythmic drugs (increase by 11±6 ms, p=0.052) and the history of cardiac surgery (increase by 26±9 ms, p=0.004) were independently associated with AFL CL. In conclusions, the distribution of AFL CL is not normal. The prevalence of AFL with short CL is low. Short CL<200 ms does not rule out the CTI-dependent AFL, especially in young and otherwise healthy patients., Š. Havránek ... [et al.]., and Obsahuje seznam literatury
Nearly all epileptic seizures in patients are characterized by deranged consciousness. We started to study changes in motivated behavior (drinking in thirsty rats) as a possible analogue of compromised consciousness during and after epileptic seizures. Epileptic afterdischarges (ADs) were elicited by stimulation of the dorsal hippocampus and/or thalamus. Rats with implanted electrodes (deprived of water for 24 hours) were trained to lick water from a narrow tube. After pretraining ADs were elicited eight times in each animal and access to water was allowed during different phases of the AD. Stimulation did not affect licking if no AD was induced. If stimulation was successful, licking was stopped in nearly 70 % of stimulations and modified (biting the tube) in 30 %. Hippocampal ADs (characterized by serrated waves in the EEG and by an arrest of behavior with subsequent automatisms) completely blocked licking, signs of recovery appeared during the interval between the AD and recurrent AD and it progressed during recurrent ADs. Thalamic ADs abolished licking in 82% of cases and immediately after ADs normal licking reappeared in 49 % of these observations. Our results suggest that changes in motivated behavior might serve as an analogue of compromised human consciousness., P. Mareš, L. Chocholová., and Obsahuje bibliografii
Extremely low-frequency magnetic field (ELF-MF) has been suggested to influence the cognitive capability but this should be dynamically evaluated in a longitudinal study. Previous training can affect performance, but the influence under magnetic field is unclear. This study aims to evaluate the effects of previous training and ELF-MF exposure on learning and memory using the Morris water maze (MWM). Sprague-Dawley rats were subjected to MWM training, ELF-MF exposure (50 Hz, 100 μT), or ELF-MF exposure combined with MWM training for 90 days. Normal rats were used as controls. The MWM was used to test. The data show that the rats exposed to training and ELF-MF with training performed better on spatial acquisition when re-tested. However, during the probe trial the rats showed no change between the training phase and the test phase. Compared with the control group, the ELF-MF group showed no significant differences. These results confirm that previous training can improve the learning and memory capabilities regarding spatial acquisition in the MWM and this effect can last for at least 90 days. However, this improvement in learning and memory capabilities was not observed during the probe trial. Furthermore, ELF-MF exposure did not interfere with the improvement in learning and memory capabilities., Y. Li, C. Zhang, T. Song., and Obsahuje bibliografii
Cellular response to ionizing radiation-induced damage depends on the cell type and the ability to repair DNA damage. Some types of cells undergo apoptosis, whereas others induce a permanent cell cycle arrest and do not proliferate. Our study demonstrates two types of response of embryonic diploid fibroblasts WI-38 to ionizing radiation. In the WI-38 cells p53 is activated, protein p21 increases, but the cells are arrested in G2 phase of cell cycle. Some of the cells die by apoptosis, but in remaining viable cells p16 increases, senescence associated DNA- damage foci occur, and senescence-associated beta-galactosidase activity increases, which indicate stress-induced premature senescence., J. Cmielová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
DNA repair is an active cellular process to respond to constant DNA damage caused by metabolic processes and environmental factors. Since the outcome of DNA damage is generally adverse and long term effects may contribute to oncogenesis, cells have developed a variety of DNA repair mechanisms, which operate depending on the type of DNA damage inflicted. At least 15 Fanconi anemia (FA) proteins interact in a common pathway involved in homologous recombination. Inherited homozygous mutations in any of these FA genes cause a rare disease, Fanconi anemia, characterized by congenit al abnormalities, progressive bone-marrow failure and cancer susceptibility. Heterozygous germline FA mutations predispose to various types of cancer. In addition, somatic FA mutations ha ve been identified in diverse cancer types. Evidence exists that cells deficient in the FA pathway become dependent on alternative pathways for survival. Additional inhibition of such alternative pathways is thus expected to result in cell death, creating a relationship of synthetic lethality. Identifying these relationships can reveal yet unknown mechanisms of DNA repair and new targets for therapy., T. Hucl, E. Gallmeier., and Obsahuje bibliografii a bibliografické odkazy
Drug abuse of pregnant women is a growing problem. The effect of prenatal drug exposure may have devastating effect on development of the offsprings that may be long-term or even permanent. One of the most common drug abused by pregnant women is methamphetamine (MA), which is also the most frequently abused illicit drug in the Czech Republic. Our previous studies demonstrated that prenatal MA exposure alters behavior, cognition, pain and seizures in adult rats in sex-specific manner. Our most recent studies demonstrate that prenatal MA exposure makes adult rats more sensitive to acute injection of the same or related drugs than their controls. The aim of the present study was to examine the effect of prenatal MA exposure on drugseeking behavior of adult male rats tested in the Conditioned place preference (CPP). Adult male rats were divided to: prenatally MA-exposed (5 mg/kg daily for the entire prenatal period), prenatally saline-exposed (1 ml/kg of physiological saline) and controls (without maternal injections). The following drugs were used in the CPP test in adulthood: MA (5 mg/kg), amphetamine (5 mg/kg), cocaine (5 and 10 mg/kg), morphine (5 mg/kg), MDMA (5 mg/kg) and THC (2 mg/kg). Our data demonstrated that prenatally MA-exposed rats displayed higher amphetamine-seeking behavior than both controls. MA as well as morphine induced drug-seeking behavior of adult male rats, however this effect did not differ based on the prenatal MA exposure. In contrast, prenatal MA exposure induced rather tolerance to cocaine than sensitization after the conditioning in the CPP. MDMA and THC did not induce significant effects. Even though the present data did not fully confirmed our hypotheses, future studies are planned to test the drug-seeking behavior also in self-administration test., R. Šlamberová, ... [et al.]., and Obsahuje seznam literatury
The aim of this study was to ascertain the persistence of heart rate and blood pressure oscillations at the onset of voluntary apnea in humans and to assess the dependence of the fluctuations` parameters on the chemoreceptor activity. In 24 young subjects (10 males, 14 females, mean age 20.4 years) heart rate (represented by its reciprocal value - RR-intervals), systolic blood pressure (SBP) and diastolic blood pressure (DBP) during controlled breathing (CB) of atmospheric air and oxygen followed by apnea were recorded continuously. The cosine functions were then fitted by nonlinear regression analysis to the heart rate, SBP and DBP oscillations during CB and at the onset of apnea. The parameters of oscillations were different during atmospheric air breathing compared to oxygen breathing. During oxygen breathing there was an increase of the RR-interval oscillations - relative bradycardia and enhanced magnitude of respiratory sinus arythmia. During apnea, the base level of the blood pressure oscillations was higher after breathing of atmospheric air compared o oxygen breathing. At least one cosine-like wave oscillation was present at the onset of apnea in the heart rate, SBP and DBP and the second wave was present in all assessed parameters in at least 70 % of recordings. The oscillations in RR-intervals are, to some extent, independent of blood pressure oscillations. No significant gender differences were found either in the duration of breath holding or in the RR and SBP oscillations parameters., M. Javorka, I. Žila, K. Javorka, A. Čalkovská., and Obsahuje bibliografii
The effect of blocking the first and rate-limiting step in renin-angiotensin cascade on the renal function in ischemia reperfusion injury has not been previously in vestigated. We investigated the effect of aliskiren, the first approved direct oral renin inhibitor, on the alterations in renal functional parameters in this condition. Wistar rats underwent left renal ischemia for 40 min. Group-1 received normal saline whereas Group-2 received aliskiren (30 mg/kg/day) by gavage for 6 days commencing one day before IRI. The hemodynamic an d tubular functions and gene expression of neutrophil gelatinase-associated lipocalin (NGAL) and plasminogen activating inhibitor (PAI-1) in the right and left kidneys were measured five days following the IRI. Comparing Group-1 and Group-2, the left renal blood flow was significantly higher in Group-2 (1.28±0.36 vs. 0.39±0.05, P=0.007). Left kidney glomerular filtration rate was also higher in Group-2 but did not reach statistical signif icance (0.18±0.05 vs. 0.10±0.02, P=0.07). The left renal FE Na was significantly lower in Group-2 (29.9±6.4 vs. 49.7±7.8, P=0.03). Aliskiren also caused a significant decrease in the gene expression of both NGAL and PAI-1 in the left ischemic kidney. In conclusions, the administration of aliskiren before and after IRI appears to have ameliorated the IRI effect on the total renal artery blood flow, and fractional excretion of sodium and gene expression of both NGAL and PAI-1 indicating a renoprotective effects in IRI., F. T. Hammad, S. Al-Salam, L. Lubbad., and Obsahuje bibliografii a bibliografické odkazy
Melatonin has been shown to play a role in antioxidative defence. We therefore studied its effect on oxidative damage to the rat cerebral cortex evoked by painful stimulation and immobilization-induced stress. Moreover, the effect of melatonin on chronic pain perception was examined. Rats were injected with either a high dose of melatonin (100 mg/kg i.p.) or a vehicle for five days and were subjected to painful stimulation or immobilization stress 30 min after the treatment. To determine the degree of oxidative stress, the levels of free radicals, thiobarbituric acid reactive substances (TBARS) as indicators of lipid peroxidation and glutathione peroxidase (GSHPx) were estimated in somatosensory cortex. Pain perception was measured by the tail-flick and plantar test. Melatonin reduced the level of TBARS previously increased by painful stimulation. Melatonin also exhibited a slight analgesic effect in those animals exposed to painful stimulation but its role in free radical scavenging did not contribute to this effect., I. Pekárková, S. Parara, V. Holeček, P. Stopka, L. Trefil, J. Racek, R. Rokyta., and Obsahuje bibliografii