Myofibrillar creatine kinase (CK) that buffers ATP during fluctuating muscle energy metabolism has been selected for studies of conformational changes underlying the cellular control of enzyme activity. The force field was computed for three energetic states, namely for the substrate-free CK molecule, for the molecule conjugated with the MgATP complex, and for the molecule conjugated with the pair of reactants MgATP-creatine. Without its substrates, the enzyme molecule assumes an inactive "open" form. Upon binding of the MgATP complex, the CK molecule takes up a reactive "closed" conformation. Subsequent binding of creatine yields a nonreactive "intermediary" conformation. Acid-base catalysis is considered to be the basic principle for the reversible transfer of the phosphoryl group between the substrates. The results indicate that the substrate-induced energy minimizing conformational changes do not represent a sufficient condition for CK activity and that some other essential component of physiological control at the cellular level is involved in the transition from the intermediary to the closed structure of the molecule., J. A. Mejsnar, B. Sopko, M. Gergor., and Obsahuje bibliografii
The design of favorable mechanical properties and suitable surface modifications of hydrogels in order to stimulate specific cell response is a great challenge. N-(2-hydroxypropyl) methacryl-amide (HPMA) was utilized to form macroporous cryogel scaffolds for stem cell applications. Furthermore, one group of scaffolds was enhanced by copolymerization of HPMA with methacryoyl-GGGRGDS-OH peptide in an effort to integrate biomimetic adhesion sites. The cryogels were characterized by stiffness and equilibrium swelling measurements as well as by scanning electron microscopy. Cell culture experiments were performed with human adipose-derived stem cells and substrates were found completely non-toxic. Moreover, RGDS-enriched cryogels supported cell attachment, spreading and proliferation, so they can be considered suitable for designed aims., A. Golunova, J. Jaroš, V. Jurtíková, I. Kotelnikov, J. Kotek, H. Hlídková, L. Streit, A. Hampl, F. Rypáček, V. Proks., and Obsahuje bibliografii
Meconium aspiration syndrome (MAS) is meconium-induced respiratory failure of newborns associated with activation of inflammatory and oxidative pathways. For severe MAS, exogenous surfactant treatment is used which improves respiratory functions but does not treat the inflammation. Oxidative process can lead to later surfactant inactivation; hence, surfactant combination with antioxidative agent may enhance the therapeutic effect. Young New Zealand rabbits were instilled by meconium suspension and treated by surfactant alone, Nacetylcysteine (NAC) alone or by their combination and oxygenventilated for 5 h. Blood samples were taken before and 30 min after meconium application and 30 min, 1, 3 and 5 h after the treatment for evaluating of oxidative damage, total leukocyte count, leukocyte differential count and respiratory parameters. Leukocyte differential was assessed also in bronchoalveolar lavage fluid. NAC alone had only mild therapeutic effect on MAS. However, the combination of NAC and surfactant facilitated rapid onset of therapeutic effect in respiratory parameters (oxygenation index, PaO2/FiO2) compared to surfactant alone and was the only treatment which prevented neutrophil migration into the lungs, oxidative damage and lung edema. Moreover, NAC suppressed IL-8 and IL-β formation and thus seems to be favorable agent for improving surfactant therapy in MAS., J. Kopincová, D. Mokrá, P. Mikolka, M. Kolomazník, A. Čalkovská., and Obsahuje bibliografii
Chronic intermittent hypoxia (CIH ) is associated with increased production of reactive oxygen species that contributes to the adaptive mechanism underlying the improved myocardial ischemic tolerance. The aim was to find out whether the antioxidative enzyme manganese superoxide dismutase (MnSOD) can play a role in CIH-induced cardioprotection. Adult male Wistar rats were exposed to intermittent hypobaric hypoxia (7000 m, 8 h/day, 25 exposures) (n=14) or kept at normoxia (n=14). Half of the animals from each group received N-acetylcysteine (NAC, 100 mg/kg) daily before the hypoxic exposure. The activity and expression of MnSOD were increased by 66 % and 23 %, respectively, in the mitochondrial fraction of CIH hearts as compared with th e normoxic group; these effects were suppressed by NAC treatment. The negative correlation between MnSOD activity and myoc ardial infarct size suggests that MnSOD can contribute to the improved ischemic tolerance of CIH hearts., P. Balková ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
An interaction between N-methyl-D-aspartate (NMDA) and MK-801 was examined in mice using a modified elevated plus-maze paradigm that allows assessment of the adaptive form of spatial memory. NMDA administered (s.c.) immediately after the acquisition session protected the animals against the amnesia induced by MK-801 given shortly before the retention session. Behavioral performance, expressed as the transfer latency, and therefore spatial memory potency of NMDA plus MK-801 treated animals was comparable with that of both NMDA-treated animals and the controls., Z. Hliňák, I. Krejčí., and Obsahuje bibliografii
Hypothalamic paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM) play an important role in brain control of blood pressure (BP). One of the important mechanisms involved in the pathogenesis of hypertension is the elevation of reactive oxygen species (ROS) production by nicotine adenine dinucleotide phosphate (NADPH) oxidase. The aim of our present study was to investigate NADPH oxidase -mediated superoxide (O 2 - ) production and to search for the signs of lipid peroxidation in hypothalamus and medulla oblongata as well as in renal medulla and cortex of hypertensive male rats transgenic for the murine Ren -2 renin gene (Ren -2 TGR) and their age -matched normotensive controls ‒ Hannover Sprague Dawley rats (HanSD) . We found no difference in the activity of NADPH oxidase measured as a lucigenin -mediated O 2 - production in the hypothalamus and medulla oblongata. However, we observed significantly elevated NADPH oxidase in both renal cortex and medulla of Ren -2 TGR com pared with HanSD. Losartan (LOS) treatment (10 mg/kg body weight/day) for 2 months (Ren -2 TGR+LOS) did not change NADPH oxidase -dependent O 2 - production in the kidney. We detected significantly elevated indirect m arkers of lipid peroxidation measured as th iobarbituric acid -reactive substance s (TBARS) in Ren -2 TGR, while they were significantly decreased in Ren -2 TGR +LOS. In conclusion, the present study shows increased NADPH oxidase activities in renal cortex and medulla with significantly increased TBARS in renal cortex. No significant changes of NADPH oxidase and markers of lipid peroxidation were detected in the studied brain regions., M. Vokurková, H. Rauchová, L. Řezáčová, I. Vaněčková, J. Zicha., and Obsahuje bibliografii
Anthracyclines, e.g. doxorubicin, pirarubicin, are widely used as cytostatic agents in the polymer nanotherapeutics designed for the highly effective antitumor therapy with reduced side effects. However, their precise dosage scheme needs to be optimized, which requires an accurate method for their quantification of the cellular level in vitro during nanocarrier development and in body fluids and tissues during testing in vivo. Various methods detecting the anthracycline content in biological samples have already been designed. most of them are highly demanding and they differ in exactness and reproducibility. The cellular uptake and localization is predominantly observed and determined by microscopy techniques, the anthracycline content is usually quantified by chromatographic analysis using fluorescence detection. We reviewed and compared published methods concerning the detection of anthracycline nanocarriers., E. Koziolova, O. Janouskova, P. Chytil, M. Studenovsky, L. Kostka, T. Etrych., and Obsahuje bibliografii
The natriuretic peptides - atrial, brain and C-type - were discovered during the last tw enty years. Their effects on cardiovascular, renal, cerebral and other tissues through guanylyl cyclase were uncovered. Over the past decade natriuretic peptides (NPs) became a very useful tool in the management of heart failure patients. Results of many clinical trials have shown that BNP and NT-proBNP are helpful for diagnosis of heart failure. They are also independent markers of prognosis not only in heart failure patients but also in patients with other cardiovascular diseases. Recently published data document the utility of NPs in guiding treatment of heart failure patients. In this article, we focus on basic biochemical and physiological characteristics of NPs as well as on their significance in management of heart failure patients. Some limitations and pitfalls of NPs levels interpretation in diagnosing heart failure are also discussed., J. Krupička ... [et al.]., and Obsahuje seznam literatury
Cardiovascular disease, while rare in women of reproductive age, is the main cause of mortality in menopause. The purpose of our study was to determine the association of natural menopause with cardiovascular risk factors, including their clustering into metabolic syndrome (MS). A random 5 % representative population sample of women aged 45-54 years was examined. In 575 women, we were able to determine their natural reproductive aging status. Multiple regression analysis was used to calculate the association between age, menopausal status, and risk factors under study. After adjustment for age, there was an increase in the odds ratio of developing MS, as defined by NCEP (OR=2.0; 95 % CI [1.1; 3.7]), and an increase in plasma lipid ratios (total cholesterol/HDL-C, LDL-C/HDL-C, apolipoprotein-B/ apolipoprotein-A1; p<0.05 for all) in postmenopausal women. Age, but not menopausal status, was associated with some single components of MS; only waist circumference significantly increased after menopause, independently of age. Clustering of risk factors in MS and lipid ratios (combined factors) was strongly associated with menopause whereas worsening of single components of MS was strongly associated with age. In conclusion, based on our results, the menopause may pose a risk to women through clustering of cardiovascular risk factors beyond simple aging., M. Lejsková ... [et al.]., and Obsahuje seznam literatury
To test the hypothesis that neonatal GLP-1 exposure may program myosin heavy chain (MyHC) composition in adult skeletal muscle, two-day-old rats were transfected intramuscularly with vacant vector plasmid (VP), or recombinant plasmid expressing secretory GLP-1 at the doses of 60 μg (LG) and 120 μg (HG), respectively. Expression of GLP-1 mRNA was detected in muscles of both LG and HG rats 7 days after transfection, with more abundant GLP-1 transcript seen in LG rats. In accordance with the GLP-1 expression, LG rats demonstrated more significant responses to neonatal GLP-1 exposure. Small yet significant growth retardation was observed in LG rats, which is accompanied with significantly reduced serum insulin concentration at 8 weeks of age compared to VP rats. The responses of skeletal muscle were dependent on muscle type. Significant increase of PGC-1α and GLUT4 mRNA expression was detected in soleus of LG rats, whereas a MyHC type switch from ⅡB to Ⅰ was seen in gastrocnemius. These results indicate that neonatal exposure of healthy pups to ectopic GLP-1 causes growth retardation with decreased serum insulin as well as muscle type-dependent modifications in MyHC type composition and metabolic gene expression in adult rats., L. Wang ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy