The long QT syndrome (LQTS) is a monogenic disorder characterized by prolongation of the QT interval on electrocardiogram and syncope or sudden death caused by polymorphic ventricular tachycardia (torsades de pointes). In general, mutations in cardiac ion channel genes (KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2) have been identified as a cause for LQTS. About 50-60 % of LQTS patients have an identifiable LQTS causing mutation in one of mentioned genes. In a group of 12 LQTS patients with no identified mutations in these genes we have tested a hypothesis that other candidate genes could be involved in LQTS pathophysiology. SCN1B and KCND3 genes encode ion channel proteins, ANK2 gene encodes cytoskeletal protein interacting with ion channels. To screen coding regions of genes SCN1B, KCND3, and 10 exons of ANK2 following methods were used: PCR, SSCP, and DNA sequencing. Five polymorphisms were found in screened candid ate genes, 2 polymorphisms in KCND3 and 3 in SCN1B. None of found polymorphisms has coding effect nor is located close to splice sites or has any similarity to known splicing enhancer motifs. Polymorphism G246T in SCN1B is a novel one. No mutation directly causing LQTS was found. Molecular mechanism of LQTS genesis in these patients remains unclear., M. Raudenská, A. Bittnerová, T. Novotný, A. Floriánová, K. Chroust, R. Gaillyová, B. Semrád, J. Kadlecová, M. Šišáková, O. Toman, J. Špinar., and Obsahuje bibliografii a bibliografické odkazy
Normal increase in hemodynamic load during early postnatal life is associated with heart growth and maturation of membrane structures that is accompanied by remodeling of membrane protein and lipid components. This review describes remodeling of phospholipids (PL) in rat myocardium during normal postnatal development and during accelerated cardiac growth induced by additional workload (aorta constriction, chronic hypoxia and hyperthyroidism) imposed on the heart early after birth. Normal physiological load after birth stimulates the development of membrane structures and synthesis of PL. While hyperthyroidism accelerates these processes, pressure overload has an inhibitory effect. These changes primarily influence the maturation of mitochondrial membranes as cardiolipin is one of the most affected PL species. The most sensitive part of PL structure in their remodeling process are PL acyl chains, particularly polyunsaturated fatty acids that are the key components determining the basic physicochemical properties of the membrane bilayer and thus the function of membrane-bound proteins and membrane-derived signaling lipid molecules. It is evident that PL remodeling may significantly influence both normal and pathological postnatal development of myocardium., F. Novák ... [et al.]., and Obsahuje seznam literatury
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
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
Although there are abundant data on ischemic postconditioning (IPoC) in the adult myocardium, this phenomenon has not yet been investigated in neonatal hearts. To examine possible protective effects of IPoC, rat hearts isolated on days 1, 4, 7 and 10 of po stnatal life were perfused according to Langendorff. Developed force (DF) of contraction was measured by an isometric force transducer. Hearts were exposed to 40 or 60 min of global ischemia followed by reperfusion up to the maximum recovery of DF. IPoC wa s induced by three cycles of 10, 30 or 60 s periods of global ischemia/reperfusion. To further determine the extent of ischemic injury, lactate dehydrogenase (LDH) release was measured in the coronary effluent. Tolerance to ischemia did not change from day 1 to day 4 but decreased to days 7 and 10. None of the postconditioning protocols tested led to significant protection on the day 10. Prolonging the period of sustained ischemia to 60 min on day 10 did not lead to better protection. The 3x30 s protocol wa s then evaluated on days 1, 4 and 7 without any significant effects. There were no significant differences in LDH release between postconditioned and control groups. It can be concluded that neonatal hearts cannot be protected by ischemic postconditioning during first 10 days of postnatal life. and J. Doul, Z. Charvátová, I. Ošťádalová, M. Kohutiar, H. Maxová, B. Ošťádal.
The present study investigated the effects of nesfatin-1 on gastric distension (GD)-responsive neurons via an interaction with corticotropin-releasing factor (CRF) receptor signaling in the ventromedial hypothalamic nucleus (VMH), and the potential regulation of these effects by hippocampal projections to VMH. Extracellular single-unit discharges were recorded in VHM following administration of nesfatin-1. The projection of nerve fibers and expression of nesfatin-1 were assessed by retrograde tracing and fluoro-immunohistochemical staining, respectively. Results showed that there were GD-responsive neurons in VMH; Nesfatin-1 administration and electrical stimulation of hippocampal CA1 sub-region altered the firing rate of these neurons. These changes could be partially blocked by pretreatment with the non-selective CRF antagonist astressin-B or an antibody to NUCB2/nesfatin-1. Electrolytic lesion of CA1 hippocampus reduced the effects of nesfatin-1 on VMH GD-responsive neuronal activity. These studies suggest that nesfatin-1 plays an important role in GD-responsive neuronal activity through interactions with CRF signaling pathways in VMH. The hippocampus may participate in the modulation of nesfatin-1-mediated effects in VMH., H. Feng, Q. Wang, F. Guo, X. Han, M. Pang, X. Sun, Y. Gong, L. Xu., and Obsahuje bibliografii
The maintenance of plasma sodium concentration within a narrow limit is crucial to life. When it differs from normal physiological patterns, several mechanisms are activated in order to restore body fluid homeostasis. Such mechanisms may be vegetative and/or behavioral, and several regions of the central nervous system (CNS) are involved in their triggering. Some of these are responsible for sensory pathways that per ceive a disturbance of the body fluid homeostasis and transmit information to other regions. These regions, in turn, initiate adequate adjustments in order to restore homeostasis. The main cardiovascular and autonomic responses to a change in plasma sodium concentration are: i) changes in arterial blood pressure and heart rate; ii) changes in sympathetic activity to the renal system in order to ensure adequate renal sodium excretion/absorption, and iii) the secretion of compounds involved in sodium ion home ostasis (ANP, Ang-II, and ADH, for example). Due to their cardiovascular effects, hypertonic saline solutions have been used to promote resuscitation in hemorrhagic patients, thereby increasing survival rates following trauma. In the present review, we exp ose and discuss the role of several CNS regions involved in body fluid homeostasis and the effects of acute and chronic hyperosmotic challenges., M. C. Dos Santos Moreira, L. M. Naves, S. M. Marques, E. F. Silva, A. C. S. Rebelo, E. Colombari, G. R. Pedrino., and Obsahuje bibliografii
Ionotropic glutamate receptors function can be affected by neurosteroids, both positively and negatively. N-methyl-D-aspartate (NMDA) receptor responses to exogenously applied glutamate are potentiated or inhibited (depending on the receptor subunit composition) by pregnenolone sulphate (PS) and inhibited by pregnenolone sulphate (3α5βS). While PS effect is most pronounced when its application precedes that of glutamate, 3α5βS only binds to receptors already activated. Synaptically activated NMDA receptors are inhibited by 3α5βS, though to a lesser extent than those tonically activated by exogenous glutamate. PS, on the other hand, shows virtually no effect on any of the models of synaptically activated NMDA receptors. The site of neurosteroid action at the receptor molecule has not yet been identified, however, the experiments indicate that there are at least two distinct extracellularly located binding sites for PS mediating its potentiating and inhibitory effects respectively. Experiments with chimeric receptors revealed the importance of the extracellular loop connecting the third and the fourth transmembrane domain of the receptor NR2 subunit for the neurosteroid action, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainate receptors are inhibited by both PS and 3α5βS. These neurosteroids also affect AMPA receptors-mediated synaptic transmission, however, in a rather indirect way, through presynaptically located targets of action., M. Sedláček, M. Kořínek, M. Petrovič, O. Cais, E. Adamusová, H. Chodounská, L. Vyklický Jr., and Obsahuje bibliografii a bibliografické odkazy
The availability of the human genome sequence and the recently completed draft sequences of two major mammalian model species, the mouse (Mus musculus) and the rat (Rattus norvegicus), allow researchers to apply novel approaches for gene identification and characterization, using methods of comparative and functional genomics. Recently, a new gene coding for apolipoprotein A-V was identified in the vicinity of APOA-I/C-III/A-IV cluster on human chromosome 11q23 by comparative sequencing method. In a relatively short time, compelling evidence accumulated for the substantial role of APOA-V in lipid metabolism. Studies in knock-out and transgenic mice revealed that its expression pattern correlates negatively with triglyceride levels. This observation was verified in human population studies in variety of ethnic and age groups. Several single nucleotide polymorphisms were described and particular SNP alleles and haplotypes in the APO A-V gene region were shown to be associated with dyslipidemia. The discovery and characterization of the APO A-V demonstrates current possibilities of the integrative approaches in biology, boosted by the available bioinformatic tools., O. Šeda, L. Šedová., and Obsahuje bibliografii