The mode of inhibition of endplate currents by four esters of 1,1-dimethyl-3-oxybutyl phosphonic acid with different lipophilicities and molecule lengths were estimated by mathematical modeling based on previous electrophysiological data supplemented by several experiments with rhythmic stimulation. The aim was to discriminate between their receptor and non-receptor effects. It was shown that all esters have a two-component mechanism of depression: inhibition of the receptor open channel and allosteric modulation of the receptorchannel complex. The ratio of both functional components depends on the length and lipophilicity of the esters. Short and less lipophilic esters mostly act as open channel inhibitors and the rate of inhibition substantially depends on the rate of stimulation, i. e. probability of the receptor-channel opening. As the length of the ester radicals and their lipophilicity increased, these compounds were more active as allosteric receptor inhibitors, probably hindering the function of nAChRs from the lipid annulus., E. Pryazhnikov ... [et al.]., and Obsahuje seznam literatury
The aim of the present study was to investigate the distribution and density of noradrenergic nerve fibres (NNFs), content of catecholamines (CATs) and steroids in the cystic ovaries of gilts receiving DXM from middle luteal phase. Cystic status of ovaries was induced by i.m. DXM injections on days 7-21 of the estrous cycle. During the same time, gilts in the control group received saline. The ovaries were collected on predicted day 11 of the second studied estrous cycle. The cystic ovaries were supplied by more numerous NNFs than the control gonads. Moreover after DXM injections, the content of CATs and progesterone and androstendione (A4) in the cystic wall were elevated, while the levels of A4, testosterone and estradiol-17β in the cystic fluid were lowered. Our results show that in the porcine cystic ovaries, induced by DXM injections from middle phase of estrous cycle, increased the density of NNFs and level of CATs, and that it was accompanied by changes in the content of steroids. Moreover, this study is a further confirmation that the morphological and functional changes of cystic ovaries are partly dependent on phase of the estrous cycle in which the induction of the ovarian cysts was initiated., A. Kozłowska, ... [et al.]., and Obsahuje seznam literatury
a1_In a series of studies in the late 1950s and early 1960s, Jan Bures introduced cortical spreading depression to the field of behavioral neuroscience (eg. Bures 1960). This technique offered a unique way to study the role of cortex in learning and memory, and attracted the attention of many who began their graduate studies at that time, including one of us (LN, cf. Nadel 1966). An NIH postdoctoral fellowship to study with the master himself brought LN to Prague in September 1967. Thus began a relationship that included science, politics, and personal life, and has lasted over 30 years1,2. The first scientific exchange began with Jan pulling a piece of paper from his desk with a long list of possible experiments written on it -- “pick one”, he said. This led to a series of studies on interhemispheric transfer of learning under conditions of monocular input, demonstrating, amongst other things, that such transfer is not a uniform process. Depending on the kind of trials given with both hemispheres intact, and the eye which remained open to input, transfer can either be non-specific, likely involving some kind of procedural knowledge, or highly specific, likely involving knowledge about the trained discrimination itself (Nadel and Buresova, 1970). These studies anticipated LN’s future work on multiple memory systems, a research enterprise pursued in the following decades by many labs (including LN’s: e.g. Nadel and O’Keefe 1974, O’Keefe et al. 1975). In this paper we focus on several scientific issues that Jan has been thinking about for the past 25 years. In particular, we consider spatial learning, the hippocampus, and memory. To this mix we add stress, something well known to anyone living in Prague in 1968., a2_LN left Prague after the 1968 invasion and stayed in London for seven months, during which time arrangements were made for an eventual return to the Medical Research Council Cerebral Functions Research Group in 1970. Thus it was that LN happened to be down the hall when John O’Keefe and Jonathan Dostrovsky discovered place cells (O’Keefe and Dostrovsky 1971) and began the program of research leading to the cognitive map theory of hippocampal function (O’Keefe and Nadel 1978)., L. Nadel, J.D. Payne., and Obsahuje bibliografii
The system of IGF-I and its binding proteins may be involved in the pathogenesis of vascular damage in Type 1 diabetes. The aim of this study was to analyze the relationship between this system and the microvascular reactivity in Type 1 diabetes as measured by laser-Doppler flowmetry. Twenty-two Type 1 diabetic patients (13 women and 9 men) with microangiopathy and fifteen healthy subjects (8 women and 7 men) were examined clinically, underwent laser-Doppler flowmetry and intima-media thickness measurements. Fasting serum levels of IGF-I, free IGF-I, IGFBPs and lipids were examined. The microvascular reactivity was impaired in Type 1 diabetic patients. Maximal perfusion during post-occlusive reactive hyperemia (PORHmax) and during thermal hyperemia (THmax) was significantly decreased in Type 1 diabetes (p<0.01). Percentage perfusion increase in both tests (PORH and TH) was lower in Type 1 diabetes mellitus (p<0.01) and the reaction after heating was slower in diabetic patients (THmax/t) (p<0.01). We did not find any significant dependence of microvascular reactivity on the parameters of IGF-I or its binding proteins. We conclude that the microvascular reactivity is impaired in Type 1 diabetes mellitus, but this impairment is not clearly dependent on the activity of the IGF-I system. It is probably only a complementary pathogenic factor., M. Kršek, M. Prázný, J. Škrha, V. Justová, Z. Lacinová, T. Haas., and Obsahuje bibliografii
Carbon dioxide interacts both with reactive nitrogen species and reactive oxygen species. In the presence of superoxide, NO reacts to form peroxynitrite that reacts with CO2 to give nitrosoperoxycarbonate. This compound rearranges to nitrocarbonate which is prone to further reactions. In an aqueous environment, the most probable reaction is hydrolysis producing carbonate and nitrate. Thus the net effect of CO2 is scavenging of peroxynitrite and prevention of nitration and oxidative damage. However, in a nonpolar environment of membranes, nitrocarbonate undergoes other reactions leading to nitration of proteins and oxidative damage. When NO reacts with oxygen in the absence of superoxide, a nitrating species N2O3 is formed. CO2 interacts with N2O3 to produce a nitrosyl compound that, under physiological pH, is hydrolyzed to nitrous and carbonic acid. In this way, CO2 also prevents nitration reactions. CO2 protects superoxide dismutase against oxidative damage induced by hydrogen peroxide. However, in this reaction carbonate radicals are formed which can propagate the oxidative damage. It was found that hypercapnia in vivo protects against the damaging effects of ischemia or hypoxia. Several mechanisms have been suggested to explain the protective role of CO2 in vivo. The most significant appears to be stabilization of the iron-transferrin complex which prevents the involvement of iron ions in the initiation of free radical reactions., A. Veselá, J. Wilhelm., and Obsahuje bibliografii
Chronic heart failure has become a significant health problem. Cardiac surgery has an important role in the treatment of patients with heart failure. There are traditional surgical techniques in cardiac surgery – coronary revascularization, valve surgery, ventricular reconstructive surgery as well as new surgical techniques – cardiac support device (CorCap), mechanical circulatory support and resynchronization therapy. Cardiac surgery has a definitive role in the treatment algorithm for chronic heart failure., J. Pirk., and Obsahuje seznam literatury
Autophagy is implicated in the maintenance of cardiac homeostasis. Autophagy is activated in heart failure, in which reactive oxygen species (ROS) are increased. Exogenous ROS have been shown to induce cardiomyocyte autophagy alterations. However, little is known about the influences of physiological levels of endogenous ROS on cardiomyocyte autophagy. In the present study, we tested the hypothesis that endogenous ROS in cardiomyocytes play an important role in inducing autophagy. Cultured H9C2 cardiomyocytes or Sprague-Dawley rats were treated with the antioxidant N-acetyl-cysteine (NAC) or the superoxide dismutase mimic tempol under the basal or nutrient deprivation conditions. The autophagic flux was assessed by the lysosomal inhibitor chloroquine. In H9C2 cardiomyocytes, under a basal condition, NAC or tempol increased the ratio of LC3 II/I proteins and reduced LC3 II autophagic flux. Under nutrient deprivation, NAC increased the LC3 II/I ratio and reduced LC3 II autophagic flux. In vivo studies in rats, NAC treatment increased the LC3 II/I ratio and p-Akt protein expression in myocardium. We concluded that the antioxidants reduced autophagic flux in cardiomyocytes under the basal or nutrient deprivation conditions, suggesting that endogenous ROS promote autophagy flux under physiological conditions, and this effect is mediated, at least in part, through Akt inhibition., J.-P. Wang, R.-F. Chi, J. Liu, Y.-Z. Deng, X.-B. Han, F.-Z. Qin, B. Li., and Seznam literatury
In the following paper, authors describe glycans present on cell membranes as they affect the folding, the spatial arrangement, the behavior and the interaction with the substrate of some membrane proteins. Authors describe the synthesis and assembly of a glycan on a protein, the formation of N-glycans, the maturation of an N-glycan in different cellular compartments, the structure of the glycocalyx and how it interacts with any pathogens. The study of the E-cadherin and the potassium channel to demonstrate how glycans affect the spatial arrangement, the stability and activity of the glycoproteins on the membranes. Subsequently, authors analyze the correlation between disorder glycosylation and human health. Authors define glycosylation disorders as a genetic defect that alter the structure or biosynthesis of glycans (sugar chains) in one or more biosynthetic pathways. Human glycosylation disorders reflect the disruption of early steps in the pathways of glycan biosynthesis. More in details, authors analyze the role of glycoprotein in tumor cell adhesion, in particular, in cells MCF-7 and MDA-MB-231 on zeolite scaffold. In the same time, the role of metalloproteinase is described in the mobilization of cancer cells and in metastasis., P. Sprovieri, G. Martino., and Seznam literatury
a1_Sarcopenia is defined as an age-associated loss of skeletal muscle function and muscle mass and is common in older adults. Sarcopenia as a disease is currently of interest not only to orthopedists and surgeons but also to internists, endocrinologists, rheumatologists, cardiologists, diabetologists, gynaecologists, geriatricians and paediatricians. In cooperation with the 5th Internal Medicine Clinic, we, as a unit of clinical research, aimed to describe a sarcopenic specific miRNA expression profile for disease diagnostics and classification of the severity of muscle performance deterioration. This study included a total of 80 patients (age 55-86 years) hospitalized at the V. Internal medicine clinic of LFUK and UNB with different severity of muscle performance deterioration. The study participants were evaluated and classified according to short physical performance battery score (SPPB). In this study, we investigated the role of circulating miRNAs in sarcopenia in the elderly. We hypothesized that sarcopenia effects the expression of muscle tissue-specific miRNAs (MyomiRNAs), which could be potentially reflected in the blood plasma miRNA expression profile. The expression of specific circulating miRNAs in patients with different muscle performances was analyzed. Patients’ blood plasma was evaluated for the expression of myomiRNAs: miRNA-29a, miRNA-29b, miRNA-1, miRNA-133a, miRNA-133b, miRNA-206, miRNA-208b and miRNA-499, and the data were correlated with diagnostic indicators of the disease. We showed a specific sarcopenia miRNA profile that could be considered a possible biomarker for the disease. Patients with low muscle performance showed increased miRNA-1, miRNA-29a and miRNA-29b expression and decreased for the miRNA-206, miRNA-133a, miRNA-133b, miRNA-208b and miRNA-499 expression., a2_ We show that the severity of muscle performance deterioration in sarcopenia correlates with specific miRNA expression. We also propose the profile of miRNAs expression in blood plasma as a specific biomarker for sarcopenia diagnostics. Future clinical studies will be necessary to eventually naturally have to elucidate the underlined molecular mechanism responsible for specific miRNAs expression in sarcopenia pathology and progression of the disease., Simona Valášková, Andrea Gažová, Petra Vrbová, Tomáš Koller, Barbara Šalingova, Adriana Adamičková, Nikola Chomaničová, Nikoleta Hulajová, Juraj Payer, Ján Kyselovič., and Obsahuje bibliografii
Numerous abnormalities of thyroid hormones in end-stage renal disease (ESRD) have been described. Our aim was to analyze the impact of these abnormalities on survival. In 167 hemodialyzed ESRD patients, TSH and thyroid hormone levels (T4, fT4, T3, fT3, rT3) were determined. The patients were then prospectively followed up for up to 5 years and the possible impact of any observed abnormalities on their mortality was studied. Only 16.8 % patients had all six tests within the reference range. The pattern of nonthyroidal illness syndrome was found in 56.3 %. Low T3 was particularly common (44.3 %), and clearly associated with increased 6- and 12-month mortality and decreased overall survival (log rank test, P=0.007). Independent of T3 levels (Spearman correlation, NS), increased rT3 was more frequently observed (9.9 %) than expected from the literature, and was also related to increased mortality and decreased survival (log rank test, P=0.021). Increased rT3 may be more common in ESRD patients than previously described, and together with decreased T3 it may serve as an indicator of poor prognosis in subsequent months., J. Horáček ... [et al.]., and Obsahuje seznam literatury