In order to re-evaluate the presence and relative quantity of 2b and 2x/d myosin heavy chain (MyHC) transcripts in rat slow soleus muscle by using real time RT-PCR we have compared the available relevant cDNA sequences and designed a new set of primers having similar melting temperatures, matching separate MyHC exons in the regions of maximal differences in MyHC coding sequences, and containing G or C at the 3́-end. These also yielded PCR products of corresponding length, which is an important requirement for real time RT-PCR quantification. The experiments were performed on 8- month-old inbred female Lewis strain rats used in our current study of regenerating transplanted muscles. The real time RT-PCR measurement confirmed the expression of all four MyHC mRNAs (type 1, 2a, 2x/d and 2b) in both fast extensor digitorum longus and slow soleus muscles, although in the soleus muscle of adult rats, only type 1 and 2a protein isoforms can be usually detected, J. Žurmanová, F. Půta, R. Stopková, T. Soukup., and Obsahuje bibliografii a bibliografické odkazy
We examined the involvement of phosphatidylinositol 3-kinase (PI3K) and its effector protein ki nase B (Akt) in cardioprotective effects of ischemic preconditioning (PC) with particular regards to its role in the protection against ischemia-induced arrhythmias in isolated perfused rat heart. PI3K/Akt inhibitor wortmannin (100 nM) was administered 15 min prior to 30-min regional (left anterior descending coronary artery occlusion) ischemia for the study of ischemic arrhythmias in the hearts perfused at constant coronary flow or prior to 30-min global ischemia followed by 2-h reperfusion for the infarct size (IS) determination (tetrazolium staining) in the hearts perfused at constant pressure. PC procedure (one cycle of isch emia/reperfusion, 5 min each) significantly reduced the total number of ventricular premature complexes (PVC) and severity of arrhythmias (arrhythmia score; AS) over the whole period of left anterior descending coronary artery occlusion in comparison with non-PC controls (PVC 166±40; AS 1.6±0.2 vs . 550±60 and 3.2±0.2; respectively; P<0.05). In a setting of global ischemia/reperfusion, PC decreased IS (in % of the left ventricle, LV) by 73 %. Pretreatment with wortmannin modified neither arrhythmogenesis nor IS in the non-PC hearts. Bracketing of PC with wortmannin did not abolish antiarrhythmic protection (PVC 92±25; AS 1.7±0.2; P<0.05 vs . non-PC hearts). On the other hand, wortmannin increased IS/LV in the PC hearts to 24±1.2 % as compared with 9 ± 0.6 % in the untreated ones (P<0.05). In conclusion, PI3K/Akt inhibition did not affect reduced arrhythmogenesis during ischemia in the PC hearts indicating that in contrast to its positive role in the irreversible myocardial injury, PI3K/Akt activity is not required for protection induced by PC against ischemic arrhythmias in the rat heart., T. Ravingerová, J. Matejíková, D. Pancza, F. Kolář., and Obsahuje bibliografii
Modifikáciou chemicko-fyzikálnych vlastností umelých materiálov určených na výrobu cievnych protéz a na podporu regenerácie cievnej steny je možné cielene regulovať adhéziu buniek, ich rast a správnu diferenciáciu. Použitím biodegradovateľných materiálov s antiadhezívnymi vlastnosťami na báze kopolyméru poly(mliečnej kyseliny) s poly(etylén oxidom) sme sa snažili vyhnúť nekontrolovanej adsorpcii proteínov zo séra, alebo z kultivačného média na umelý materiál a neriadenej adhézii buniek. Súčasne to umožňuje predchádzať možným imunitným reakciám, které môžu nastať pri použití cizorodého séra pri kultivácii buniek. Naviazaním vhodných špecifických ligandov pro integrínové receptory- oligopeptidu GRGDSG- na tieto antiadhezívne povrchy sme dosiahli kontrolovanú adhéziu hladkých svalových buniek, sprostredkovanú integrínovými receptormi. Vhodným výberom ligandov-oligoproteínov, ich koncentráciou a konformačným usporiadaním je možné ďalej regulovať adhéziu, rast a proliferáciu určitých typov buniek (hladké svaly, endoteliálne bunky a pod.) potrebných na vytvorenie funkčnej cievnej steny., Elena Filová, Lucie Bačáková, Věra Lisá, Dana Kubies, Luďka Machová, Vladimír Proks, František Rypáček., and Obsahuje seznam literatury
Using non-cholesterol sterols investigation several authors postulated a hypothesis that in the metabolic syndrome cholesterol endogenous synthesis is increased and its absorption decreased. Our study is the first attempt to evaluate the direct relation of cholesterol metabolism to the principal pathogenetic phenomenon of the metabolic syndrome – namely to insulin resistance. We have measured insulin sensitivity by two methods – Quicki (Quantitative Sensitivity Check Index) and intravenous insulin tolerance test (Kitt) and 3 indirect markers - fasting insulin level, fasting C-peptide level and SHBG (sex hormone binding globulin). The investigation was performed in three groups of subjects with a different prevalence of insulin resistance: 72 non-diabetics with ischemic heart disease, 117 young blood donors and 63 type 2 diabetics on diet therapy only. Analyzing altogether 60 relationships – between four sterols (lathosterol, squalene, sitosterol and campesterol) and five markers of insulin resistance in three groups of subjects – we have found only six significant relations between cholesterol synthesis and absorption and insulin resistance in all groups of patients. Our results indicate that there exists a significant relationship between insulin sensitivity and indices of either increased cholesterol synthesis or decreased cholesterol absorption. Insulin resistance explains only a part of both abnormalities mentioned above., A. Šmahelová, R. Hypšler, T. Haas., and Obsahuje bibliografii a bibliografické odkazy
Previous investigations revealed that most of the fluid regulating hormones showed no consistent relationship to the hypoxic diuretic response (HDR). In this study we examined if adrenomedullin (AM), a hypoxia-mediated diuretic/natriuretic peptide is connected to HDR. Thirty-three persons were examined at low altitude (LA), on the third exposure day at 3440 m (medium altitude, MA) and on the fourteenth day at 5050 m (high altitude, HA). Nocturnal diuresis rose from 460 ml [interquartile range 302 ml] at LA to 560 [660] ml at MA to 1015 [750] ml at HA (p<0.005). Sodium excretion was similar at LA and MA (41.8 [27.0] vs. 41.4 [28.4] mM) and increased to 80.2 [29.1] mM at HA (p<0.005). Urinary AM excretion was 7.9 [3.9] at LA, 7.5 [5.7] pM at MA, and increased to 10.5 [5.1] pM (p<0.05) at HA. Urinary AM excretion was correlated to diuresis (r=0.72, p<0.005) and sodium excretion (r=0.57, p<0.005). Plasma AM concentration rose from 16.4 [3.1] to 18.8 [4.9] pM/l at MA (p<0.005) and to 18.3 [4.3] pM/l at HA (p<0.005). Plasma AM concentration and urinary AM excretion were not correlated, neither were plasma AM concentration and diuresis or natriuresis. Our data suggest the involvement of increased renal AM production in the pathophysiology of high altitude fluid and sodium loss., B. Haditsch, A. Roessler, H. G. Hinghofer-Szalkay., and Obsahuje bibliografii a bibliografické odkazy
We present the current state of complex circulatory dynamics model development based on Guyt on’s famous diagram. The aim is to provide an open-source model that will allow the simulation of a number of pathological conditions on a virtual patient including cardiac, respiratory, and kidney failure. The model will also simulate the therapeutic influence of various drugs, infusions of electrolytes, blood transfusion, etc. As a current result of implementation, we describe a co re model of human physiology targeting the systemic circulation, arterial pressure and body fluid regulation, including short- and long-term regulations. The model can be used for educational purposes and general reflection on physiological regulation in path ogenesis of various diseases., J. Kofránek, J. Rusz., and Obsahuje bibliografii
Neonatal exposure to hyperoxia alters lung development in mice. We tested if retinoic acid (RA) treatment is capable to affect lung development after hyperoxic injury and to maintain structural integrity of lung. The gene of vascular endothelial growth factor A (VEGF-A) is one of the RA-responsive genes. Newborn BALB/c mice were exposed to room air, 40 % or 80 % hyperoxia for 7 days. One half of animals in each group received 500 mg/kg retinoic acid from day 3 to day 7 of the experiment. At the end of experiment we assessed body weight (BW), lung wet weight (LW), the wet-to-dry lung weight ratio (W/D) and the expression of mRNA for VEGF-A and G3PDH genes. On day 7 the hyperoxia-exposed sham-treated mice (group 80) weighed 20 % less than the room air-exposed group, whereas the 80 % hyperoxic group treated with RA weighed only 13 % less than the normoxic group. W/D values in 80 and 80A groups did not differ, although they both differed from the control group and from 40 groups. There was a significant difference between 40 and 40A groups, but the control group was different from 40 group but not from 40A groups. The 80 and 80A groups had mRNA VEGF-A expression lowered to 64 % and 41 % of the control group. RA treatment of normoxic and mild hyperoxic groups increased mRNA VEGF-A expression by about 50 %. We conclude that the retinoic acid treatment of newborn BALB/c mice exposed for 7 days to 80 % hyperoxia reduced the growth retardation in the 80 % hyperoxic group, reduced the W/D ratio in the 40 % but not in the 80 % hyperoxic group. Higher VEGF-A mRNA expression in the 80 % hyperoxic group treated with RA was not significant compared to the 80 % hyperoxic group., M. Zimová-Herknerová, J. Mysliveček, P. Potměšil., and Obsahuje bibliografii a bibliografické odkazy
Central administration of losartan effectively blocked the increase of blood pressure and drinking response induced by angiotensin II (Ang II) or carbachol. However, the relationship between angiotensin AT1 receptors and the natriuresis induced by brain cholinergic stimuli is still not clear. The purpose of the study is to reveal the role of brain angiotensin AT1 receptor in the carbachol-induced natriuresis and expression of neuronal nitric oxide synthase (nNOS) in the locus coeruleus (LC) and proximal co nvoluted tubule (PCT). Our results indicated that 40 min after in tracerebroventricular (ICV) injection of carbachol (0.5 μg), urinary sodium excretion was significantly increased to 0.548±0.049 μmol·min-1·100 g-1. Immunohistochemistry showed that carbachol induced an increase of neuronal nitric oxide synthase immunoreactivity (nNOS-IR) in the LC and renal proximal tubular cells. After pretreatment with losartan (20 μg), carbachol-induced urinary sodium excretion was reduced to 0.249±0.067 μmol·min-1·100 g-1. The same was true for carbachol-induced increase of nNOS-IR in the LC and PCT. The present data suggest that ICV cholinergic stimulation could induce a natriuresis and upregulate the activity of nNOS in the LC and PCT. The blockade of AT1 receptors might downregulate the effects induced by carbachol in the LC and PCT. Consequently, we provide a new evidence that brain angiotensinergic pathway and NO-dependent neural pathway contribute to the natriuresis following brain cholinergic stimulation and thus play an important role in the regulation of fluid homeostasis. Furthermore, the final effect of nitric oxide on proximal tubular sodium reabsorption participated in the natriuresis induced by brain cholinergic stimulation., M. Wang, C. L. Jiang, C. Y. Wang, Q. Y. Yao., and Obsahuje bibliografii a bibliografické odkazy
Ghrelin, an endogenous ligand for growth hormone secretagogue receptor (GHS-R), has been id entified in the rat and human gastrointestinal tract. Ghrelin has been proposed to play a role in gastric acid secretion. Nitric oxide (NO) was shown as a mediator in the mechanism of ghrelin action on gastric acid secretory function. However, there is a little knowledge about this topic. We have investigated the role of ghrelin in gastric acid secretion and the role of NO as a mediator. Wistar albino rats were used in this study. The pyloric sphincter was ligated through a small midline incision. By the time, saline (0.5 ml, iv) was injected to the control group, ghrelin (20 μg/kg, iv) was injected to the first experimental group, ghrelin (20 μg/kg, iv) +L-NAME (70 mg/kg, sc) was injected to the second group and L-NAME (70 mg/kg, sc) was administered to the third group. The rats were killed 3 h after pylorus ligation; gastric acid secretion, mucus content and plasma nitrite levels were measured. Exogenous ghrelin administration increased gastric acid output, mucus content and total plasma nitrite levels, while these effects of ghrelin were inhibited by applying L-NAME. We can conclude that ghrelin participates in the regulation of gastric acid secretion through NO as a mediator., H. M. Bilgin, C. Tumer, H. Diken, M. Kelle, A. Sermet., and Obsahuje bibliografii a bibliografické odkazy
Mammalian P2X receptors contain 10 conserved cysteine residues in their ectodomains, which form five disulfide bonds (SS1-5). Here, we analyzed the relevance of these disulfide pairs in rat P2X4 receptor function by replacing one or both cysteines with alanine or threonine, expressing receptors in HEK293 cells and studying their responsiveness to ATP in the absence and presence of ivermectin, an allostenic modulator of these channels. Response to ATP was not altered when both cysteines forming the SS3 bond (C132-C159) were replaced with threonines. Replacem ent of SS1 (C116-C165), SS2 (C126-C149) and SS4 (C217-C227), but not SS5 (C261-C270), cysteine pairs with threonines resulted in de creased sensitivity to ATP and faster deactivation times. The maximum current amplitude was reduced in SS2, SS4 and SS5 double mutants and could be partially rescued by ivermectin in SS2 and SS5 double mutants. This response pattern was also observed in numerous single residue mutants, but receptor function was not affected when the 217 cysteine was replaced with threonine or arginine or when the 261 cysteine was replaced with alanine. These results suggest that the SS1, SS2 and SS4 bonds contribute substantially to the structure of the ligand binding pocket, while the SS5 bond located towards the transmembrane domain contributes to receptor gating., M. B. Rokic, V. Tvrdoňová, V. Vávra, M. Jindřichová, T. Obšil, S. S. Stojilkovic, H. Zemková., and Obsahuje bibliografii