Hypotonic solution alters ion channel activity, but little attention has been paid to voltage-dependent sodium channels. The aim of this study was to investigate the effects of hypotonic solution on transient sodium currents (INaT) and persistent sodium currents (INaP). We also explored whether the intracellular signal transduction systems participated in the hypotonic modifications of sodium currents. INaT and INaP were recorded by means of whole-cell patch-clamp technique in isolated rat ventricular myocytes. Our results revealed that hypotonic solution reduced INaT and simultaneously augmented INaP with the occurrence of interconversion between INaT and INaP. Hypotonic solution shifted steady-state inactivation to a more negative potential, prolonged the time of recovery from inactivation, and enhanced intermediate inactivation (IIM). Ruthenium red (RR, inhibitor of TRPV4), bisindolylmaleimide VI (BIM, inhibitor of PKC), Kn-93 (inhibitor of Ca/CaMKII) and BAPTA (Ca2+-chelator) inhibited the effects of hypotonic solution on INaT and INaP. Therefore we conclude that hypotonic solution inhibits INaT, enhances INaP and IIM with the effects being reversible. TRPV4 and intracellular Ca2+, PKC and Ca/CaMKII participate in the hypotonic modifications of sodium currents., L. Hu ... [et al.]., and Obsahuje seznam literatury
The diffusion of neuroactive substances in the extracellular space (ECS) plays an important role in short- and long-distance communication between nerve cells and is the underlying mechanism of extrasynaptic (volume) transmission. The diffusion properties of the ECS are described by three parameters: 1. ECS volume fraction α (α = ECS volume/ total tissue volume), 2. tortuosity λ (λ2 = free /apparent diffusion coefficient), reflecting the presence of diffusion barriers represented by, e.g., fine neuronal and glial processes or extracellular matrix molecules and 3. nonspecific uptake k’. These diffusion parameters differ in various brain regions, and diffusion in the CNS is therefore inhomogeneous. Moreover, diffusion barriers may channel the migration of molecules in the ECS, so that diffusion is facilitated in a certain direction, i.e. diffusion in certain brain regions is anisotropic. Changes in the diffusion parameters have been found in many physiological and pathological states in which cell swelling, glial remodeling and extracellular matrix changes are key factors influencing diffusion. Changes in ECS volume, tortuosity and anisotropy significantly affect the accumulation and diffusion of neuroactive substances in the CNS and thus extrasynaptic transmission, neuron-glia communication, transmitter „spillover“ and synaptic cross-talk as well as cell migration, drug delivery and treatment., L. Vargová, E. Syková., and Obsahuje bibliografii a bibliiografické odkazy
This paper describes an ongoing project that has the aim to develop a low cost application to replace a computer mouse for people with physical impairment. The application is based on an eye tracking algorithm and assu mes that the camera and the head position are fixed. Color tracking and template matching methods are used for pupil detection. Calibration is provided by neural networks as well as by parametric interpolation methods. Neural networks use back-propagation for learning and bipolar sigmoid function is chosen as the activation function. The user’s eye is scanned with a simple web camera with backlight compensation which is attached to a head fixation device. Neural networks significantly outperform parametric interpolation techniques: 1) the calibration proc edure is faster as they require less calibration marks and 2) cursor control is more precise. The system in its current stage of de velopment is able to distinguish regions at least on the level of desktop icons. The main limitation of the proposed method is the lack of head-pose invariance and its relative sensitivity to illumination (especially to incidental pupil reflections)., E. Demjén, V. Aboši, Z. Tomori., and Obsahuje bibliografii a bibliografické odkazy
Apolipoprotein E (apoE) is a polymorphic protein which occurs in three common isoforms and more than 25 rare variants. Some of the rare apoE variants have been implicated in a dominant mode of inheritance of familial dysbetalipoproteinemia (FD). We have identified three unrelated apoE 2*(Arg136®Cys) carriers with FD. This finding supports the notion that although apoE 2*(Arg136®Cys) mutation is perhaps not sufficient to cause FD itself, the presence of other genetic and/or environmental factors can lead to the phenotypic expression of the disease in the carriers., M. Vrablík, A. Hořínek, R. Češka, T. Štulc, T. Kvasnička., and Obsahuje bibliografii
Familial hypercholesterolemia (FH) is the most common autosomal dominant disorder. It is characterized by a de crease in LDL cholesterol catabolism and an early clinical manifestation of atherosclerotic vessel damage. The aim of the MedPed (Make early diagnosis to Prevent early deaths) project is an early diagnosis of FH patients in order to profit from early treat ment and prevent cardiov ascular events. Till November 30, 2016 The Czech National MedPed Database has registered 7,001 FH patients from 5,223 different families that is 17.4 % of expected patients in the Czech Republic considering 1:250 FH prevalence. The improvement in diagnostic accuracy, patient cooperation and above all familial cascade screening is enabled by FH mutation detection using the modern technology of next-generation sequencing. FH still remain undiagnosed even though the Czech Republic is on e of the most successful countries with respect to FH detection. The opportunities of international collaboration and experience sharing within international programs (e.g. EAS FHSC, ScreenPro FH etc.) will improve the detection of FH patients in the futur e and enable even more accessible and accurate genetic diagnostics., M. Vrablík, M. Vaclová, L. Tichý, V. Soška, V. Bláha, L. Fajkusová, R. Češka, M. Šatný, T. Freiberger., and Obsahuje bibliografii
Familial hypocalciuric hypercalcemia (FHH) type 1, caused by a heterozygous inactivating mutation of the gene encoding the calcium-sensing receptor (CaSR), is characterized by mild to moderate hypercalcemia, hypocalciuria and inappropriately normal or elevated parathyroid hormone (PTH). FHH must be differentiated from primary hyperparathyroidism (PHPT) because parathyroidectomy is ineffective in the former. Herein, we report a 39-year-old male patient with a 13-year history of asymptomatic PTH-dependent hypercalcemia (mean calcium of 2.88 mmol/l; reference range 2.15-2.55 mmol/l) and calcium-tocreatinine clearance ratio (Ca/Cr) ranging from 0.007 to 0.0198, which is consistent with either FHH or PHPT. Although a family history of hypercalcemia was negative, and PET-CT with fluorocholine was suggestive of a parathyroid adenoma, genetic analysis of the CaSR gene identified a heterozygous inactivating mutation NM_000388.4:c.1670G>A p. (Gly557Glu) in exon 6 and a polymorphism NM_000388.4:c.1192G>A p. (Asp398Asn) in exon 4. The G557E mutation has been previously reported in a Japanese family in which all family members with the mutation had Ca/Cr below 0.01 consistent with FHH. The biochemical profile of FHH and PHPT may overlap. Our FHH patient with a G557E CaSR mutation illustrates that the differential diagnosis can be difficult in an index case with no family history, (false) positive parathyroid imaging and higher calciuria than expected for FHH. Calcium intake, vitamin D status and bone resorption might have contributed to the Ca/Cr variations over a 13-year clinical follow up. This case thus emphasizes the irreplaceable role of genetic testing of the CaSR gene when clinical evaluation is inconclusive., Kateřina Zajíčková, Marcela Dvořáková, Jitka Moravcová, Josef Včelák, David Goltzman., and Obsahuje bibliografii
Objective: To examine the impact of family history of diabetes mellitus 2 (DM 2) on insulin sensitivity and secretion in lean women with polycystic ovary syndrome (PCOS). Thirteen healthy women (C), 14 PCOS without family history of DM 2 (FH-) and 8 PCOS with family history of DM 2 (FH+) were examined using euglycemic hyperinsulinemic clamp and an arginine secretion test (insulin and glucagon at fasting glycemia (AIRFG and AGRFG) and at hyperglycemia (AIR14 and AG 14)). FH+ women were more insulin resistant than FH- with lower insulin sensitivity index corrected per lean body mass (p<0.05). They had significantly higher triglycerides (p<0.05) and lower HDL-cholesterol (p<0.05) than C or FH- women. Concerning insulin secretion, AIR FG was increased in FH+ women comparing FH- women (p<0.05). Disposition indices derived from AIRFG or AIR14 and insulin sensitivity index did not differ between FH+ or FH-. Thus, women with PCOS with the concomitant family history of DM 2 have lower insulin sensitivity than healthy control women. Insulin resistance observed in these women with PCOS is compensated by increased insulin secretion., J. Vrbíková, T. Grimmichová, K, Dvořáková, M. Hill, S. Stanická, K. Vondra., and Obsahuje bibliografii a bibliografické odkazy
The aim of the present study wa s to compare the immediate and delayed locomotor response to high-dose nicotine (NIC) administration in rats. The vertic al and horizontal activity of behavior in adult male rats exposed to 1 mg/kg NIC or saline (SAL) were tested in a Laboras apparatus for one hour after drug application. Animals were then returned to their cages and housed for another seven days. After this period all animals were placed in Laboras again and their behavioral pattern was retested for another period of one hour (delayed response). Horizontal activity: immediately af ter nicotine administ ration animal were less mobile (first 2-minutes interval), when compared with controls. The immobilization effect of nicotine disappeared within 4 minutes and during whole first 10-minutes interval time spent by locomotion did not differ from controls. Locomotion activity of animals treated with nicotine increased robustly in following 10 minutes and remained significan tly higher in 2nd, 3rd and 5th 10-minutes interval. Vertical activity: Rearing frequency was significantly lowered by NIC administration in first two minutes of the experiment and the same was found when the duration of rearing was analyzed. Lower rearing intensity of NIC treated animals disappeared in 4 minutes and was finally higher during whole test session as compared with controls. When duration of rearing was analyzed it was significantly longer in NIC treated animals. In majority of observed behavioral aspects there were no differences between NIC treated rats and controls seven days after NIC or SAL treatment. Our results reflect effect of NIC and we conclude that NIC significantly influences behavior of experimental animals., K. Jandová, D. Marešová, J. Pokorný., and Obsahuje bibliografii a bibliografické odkazy
Moderately elevated plasma/serum triglycerides (2 -10 m mol/l) signalize increased risk for cardiovascular disease or presence of non- alcoholic steatohepatitis. Extremely elevated triglycerides (more than 10 mmol/l) signalize increased risk for pancreatitis and lipemia retinalis. The concentration of triglycerides is regulated by many genetic and nongenetic factors. Extremely elevated triglycerides not provoked by nutritional factors, especially inappropriate alcohol intake are more likely to have a monogenic cause. On the contrary, mildly to moderately elevated triglycerides are often caused by polygenic disorders; these could be also associated with central obesity, insulin resistance, and diabetes mellitus. Concentration of triglycerides is also closely interconnected with presence of atherogenic remnant lipop roteins, impaired reverse cholesterol transport and more atherogenic small LDL particles. In general, there is tight association between triglycerides and many other metabolic factors including intermediate products of lipoprotein metabolism which are freq uently atherogenic. Therefore, reliable evaluation of the independent role of triglycerides especially in atherosclerosis and cardiovascular disease is difficult. In individual cases values of HDL cholesterol, non -HDL cholesterol (total minus HDL cholester ol), non -HDL/nonLDL cholesterol (total minus HDL minus LDL cholesterol, especially in nonfasting status), atherogenic index of plasma and/or apolipoprotein B could help in decisions regarding a ggressiv eness of treatment., J. Piťha, J. Kovář, T. Blahová., and Obsahuje bibliografii
The aim of our study was to evaluate rapid insulin pulses and insulin secretion regularity in fasting state in lean women with polycystic ovary syndrome (PCOS) in comparison to lean healthy women. PCOS (n=8) and controls (n=7) underwent every minute blood sampling for 60 min. Insulin pulsatility was assessed by deconvolution and insulin secretion regularity by approximate entropy methodology. PCOS had higher testosterone (p<0.02), prolactin (p<0.05) and lower sex hormone binding globulin (SHBG) (p<0.0006) levels than controls. Approximate entropy, insulin pulse frequency, mass, amplitude and interpulse interval did not differ between PCOS and controls. PCOS had broader insulin peaks determined by a common half-duration (p<0.07). Burst mass correlated positively with testosterone (p<0.05) and negatively with SHBG (p<0.0004) and common half-duration correlated positively with prolactin (p<0.008) and cortisol levels (p<0.03). Approximate entropy positively correlated with BMI (p<0.04) and prolactin (p<0.03). Lean PCOS patients tended to have broader insulin peaks in comparison to healthy controls. Prolactin, androgens and cortisol might participate in alteration of insulin secretion in PCOS-affected women. Body weight and prolactin levels could influence insulin secretion regularity., T. Grimmichová, J. Vrbíková, P. Matucha, K. Vondra, P. P. Veldhuis, M. L. Johnson., and Obsahuje bibliografii a bibliografické odkazy