The aim of this study was to examine the influence of unilateral dorsal root section at the cervicothoracic level of the spinal cord on the spontaneous neuronal activity of medial thalamic nuclei in the rat. Single unit extracellular recordings from thalamic nuclei, nc. parafascicularis and nc. centralis lateralis, were obtained with glass micropipettes. The abnormal bursting activity of these nuclei following deafferentation was registered, although a correlation between the occurrence of this activity and the degree of autotomy behavior was not found. Such bursts were never observed in the studied thalamic nuclei of control rats., Š. Vaculín, M. Franěk, R. Rokyta., and Obsahuje bibliografii
We have analyzed the influence of altered thyroid hormone levels on changes of MyHC protein isoforms and their mRNA transcripts in the soleus muscle of 2-, 4- and 7-month-old euthyroid (EU), hypothyroid (HY) and hyperthyroid (TH) female inbred Lewis strain rats (methimazole and T3 treatment started 3 to 4 weeks after birth). We have found that the content of the dominant MyHC 1 isoform gradually increased in the EU rats and that this increase was more progressive in the HY rats at all three stages. On the other hand, in the TH rats the content of MyHC 1 isoform was the highest in the 2-month-old rats and it decreased with an increasing length of T3 treatment. The content of the minor 2a MyHC isoform followed the opposite pattern. In contrast to the protein isoforms, the MyHC mRNA transcripts remained at similar levels. Nevertheless, in general, the MyHC 1 mRNA level was decreased and MyHC 2a transcript increased in the TH rats, while the opposite changes occurred in the HY rats. Our results thus suggest that in the rat soleus muscle, both increased and decreased levels of thyroid hormones speed up the formation of an adult slow phenotype which is demonstrated by the precocious appearance of the slow MyHC 1 isoform, but opposite to the hypothyroid status, a longer T3 application promotes the expression of the faster MyHC 2a isoform., A. Vadászová-Soukup, T. Soukup., and Obsahuje bibliografii a bibliografické odkazy
In this study, we describe changes of plasma levels of the hypothalamic neuropeptide orexin A in obese children during the reduction of body weight and its relationship to other biochemical and anthropometrical parameters. We measured orexin A fasting plasma levels by the RIA method in 58 obese children - 33 girls and 25 boys; mean age 13.1±0.38 years (range 7-18.5) before and after 5 weeks of weight-reduction therapy. Leptin, IGF-1, and IGFBP-3 levels were measured in all the subjects and were compared to orexin A levels and anthropometrical data. Average weight in subjects before weight-reduction was 74.2±2.79 kg and after weight-loss 67.4±2.60 kg (p<0.0001). Orexin A levels before the therapy were 33.3±1.97 pg/ml and after the therapy 51.7±3.07 pg/ml (p<0.0001). Levels of orexin A were not significantly different between girls and boys (p=0.7842). We found negative correlation between orexin A and age (r = -0.5395; p<0.0001), body height (r = -0.4751; p=0.0002), body weight (r = -0.4030; p=0.0017) and BMI (r = -0.2607; p=0.0481). No correlation was found between orexin A and IGF-1, IGFBP-3 or leptin. Orexin A plasma levels increased during body weight loss, whereas the reverse was true for leptin levels. These findings support the hypothesis that orexin A may be involved in regulation of nutritional status in children., J. Bronský, J. Nedvídková, H. Zamrazilová, M. Pechová, M. Chada, K. Kotaška, J. Nevoral, R. Průša., and Obsahuje bibliografii a bibliografické odkazy
Anthracycline cardiotoxicity represents a serious risk of anticancer chemotherapy. The aim of the present pilot study was to compare the potential of both the left ventricular (LV) filling pattern evaluation and cardiac troponin T (cTnT) plasma levels determination for the early detection of daunorubicin-induced cardiotoxicity in rabbits. The echocardiographic measurements of transmitral LV inflow as well as cTnT determinations were performed weekly for 10 weeks in daunorubicin (3 mg/kg weekly) and control groups (n=5, each). Surprisingly, no significant changes in LV-filling pattern were observed through the study, most likely due to the xylazine-containing anesthesia, necessary for appropriate resolving of the E and A waves. In contrast to the echographic measurement, the dP/dt min index obtained invasively at the end of the study revealed a significant im pairment in LV relaxation, which was further supported by observed disturbances in myocardial collagen content and calcium homeostasis. However, at the same time cTnT plasma levels were progressively rising in the daunorubicin-treated animals from the 5th week (0.024±0.008 μg/l) until the end of the experiment (0.186±0.055 μg/l). Therefore, in contrast to complicated non-invasive evaluation of diastolic function, cTnT is shown to be an early and sensitive marker of anthracycline-induced cardiotoxicity in the rabbit model., M. Štěrba, T. Šimůnek, O. Popelová, A. Potáčová, M. Adamcová, Y. Mazurová, M. Holečková, V. Geršl., and Obsahuje bibliografii a bibliografické odkazy
Reduced physical activity and abundant energy intake are two most common factors leading to uncontrolled body weight gain. But these factors are not under entire internal consciousness control; they are also partially genetically determined and are affected by for example food marketing practices. In addition to these two widely accepted factors, there are some other factors, whose could also contribute to the recent increase of obesity prevalence. For example, non-exercise activity thermogenesis, sleeping habits, more stable inside room temperatures (using of heating and air conditioning), high prescription of medications with weight gain as side effect, psychosocial factors, unfavourable socioeconomic status and unpleasant urban environment are the background factors which should not be omitted if obesity/BMI determination should be fully understood and kept under control. In conclusion, unhealthy life style is necessary, but not sufficient for obesity development., J. A. Hubáček., and Obsahuje seznam literatury
Enzymes that hydrolyze extracellular ATP, i.e. ecto-ATPase and ecto-ATP diphosphohydrolase (ATPDase), can be differentiated by ability of the latter to hydrolyze ADP and by slightly different kinetic properties of the two enzymes. Synaptic plasma membrane fractions isolated from rat hippocampus and caudate nucleus exhibit ADP-hydrolyzing activity, as revealed by the enzyme assay, and the presence of ecto-ATPase protein, as revealed by immunological identification on Western blot. These findings indicate that both enzymes are co-expressed in the synaptic membrane compartment of hippocampal and caudate nucleus neurons. Kinetic analysis was performed to determine the relative contribution of each enzyme to the total ATP-hydrolyzing activity, while an inhibition study was carried out in order to exclude the interference of other nonspecific ATPase and phosphatase activities. Based on the kinetic properties, sensitivity to inhibitors and VATP/VADP ratio of about 2, we concluded that a substantial portion of ATP-hydrolyzing activity in both synaptic membrane preparations can be ascribed to the catalytic action of ATPDase. On the other hand, the highest catalytic efficacy when ATP is the substrate and the greater abundance of ecto-ATPase protein in caudate nucleus preparation suggest that the relative contribution of ecto-ATPase to the total ATP-hydrolyzing activity in the caudate nucleus is higher than in the hippocampus., N. Nedeljkovic, A. Banjac, A. Horvat, M. Stojiljkovic, G. Nikezic., and Obsahuje bibliografii
The role of brain derived nitric oxide in the physiology and behavior remains disputable. One of the reasons of the controversies might be systemic side effects of nitric oxide synthase inhibitors. Therefore, under nNOS inhibition by 7- nitroindazole (7-NI) we carried out recordings of blood gasses, blood pressure and spontaneous EEG in conscious adult rats. Locomotion and spontaneous behavior were assessed in an open field. In addition skilled walking and limb coordination were evaluated using a ladder rung walking test. The blood gas analysis revealed a significant increase in pCO2 180 min and 240 min after the application of 7-NI. The power and entropy decreased simultaneously with a shift of the mean frequency of the spontaneous EEG toward slow oscillations after 7-NI treatment. The thresholds of evoked potentials underwent a significant drop and a trend towards a slight increase in the I-O curve slope was observed. 7-NI significantly suppressed open field behavior expressed as distance moved, exploratory rearing and grooming. As for the ladder rung walking test the 7-NI treated animals had more errors in foot placement indicating impairment in limb coordination. Therefore our findings suggest that 7-NI increased cortical excitability and altered some physiological and behavioral parameters., C. Boržíčková, A. Mikulecká, J. Otáhal., and Obsahuje bibliografii
Statins are powerful lipid-lowering drugs, widely used in patients with hyperlipidemia and coronary artery disease. It was found, however, that statins appear to have a pleiotropic effect beyond their lipid-lowering ability. They exert anti-inflammatory, antithrombotic and antioxidant effects, increase nitric oxide production and improve endothelial dysfunction. The aim of our study was to examine the effect of chronic and acute treatment with simvastatin on the contractile function of the isolated perfused rat heart after ischemia/reperfusion injury. Contractile function was measured on isolated rat hearts, perfused according to Langendorff under constant pressure. The hearts were subjected to 20 min of global ischemia, followed by 40 min of reperfusion. To investigate the acute effect, simvastatin at a concentration of 10 μmol/l was added to the perfusion solution during reperfusion. In chronic experiments the rats were fed simvastatin at a concentration of 10 mg/kg for two weeks before the measurement of the contractile function. Acute simvastatin administration significantly increased reparation of the peak of pressure development [(+dP/dt)max] (52.9±8.2 %) after global ischemia, as compared with the control group (28.8±5.2 %). Similar differences were also observed in the time course of the recovery of [(+dP/dt)max]. Chronic simvastatin was without any protective effect. Our results reveal that the acute administration of simvastatin during reperfusion, unlike the chronic treatment, significantly reduced contractile dysfunction induced by ischemia/reperfusion injury. This supports the idea of possible cardioprotective effect of statin administration in the first-line therapy of the acute coronary syndrome., O. Szárszoi, J. Malý, P. Ošťádal, I. Netuka, J. Bešík, F. Kolář, B. Ošťádal., and Obsahuje bibliografii a bibliografické odkazy