We studied the psychophysiology of soluble intercellular adhesion molecule-1 (sICAM-1) in 25 apparently healthy middle-aged men who underwent an acute psychosocial stressor three times with one week apart. Measures of the biological stress response were obtained at week one and three. The magnitude of the sICAM-1 stress response showed no habituation between individual visits. At week one, cognitive stress appraisal independently predicted integrated sICAM-1 area under the curve (AUC) between rest, immediately post-stress, and 45 min and 105 min post-stress (β=0.67, p=0.012, ΔR2=0.41). Diastolic blood pressure AUC (β=-0.45, p=0.048, ΔR2=0.21) and heart rate AUC (β=0.44, p=0.055, ΔR2=0.21) were independent predictors of sICAM-1 AUC at week three. Adjustment for hemoconcentration yielded a decrease in sICAM-1 levels from rest to post-stress (p<0.001). Stress responsiveness of plasma sICAM-1 was predicted by stress perception and hemodynamic reactivity and affected by stress-hemoconcentration but unrelated to cortisol reactivity and not readily adapting to repeated stress., R. von Känel, D. Preckel, B. M. Kudielka, J. E. Fischer., and Obsahuje bibliografii a bibliografické odkazy
Antiorthostatic hindlimb suspension (unloading) decreased the resting membrane potential (RMP) of skeletal muscle fibers in fast extensor digitorum longus (EDL) and slow soleus (SOL) muscle of the rat by about 10 % within 7 days and more. Inactivation of the membrane Na+,K+-pump by ouabain brought about similar depolarization as unloading. The increased sodium permeability of the membrane was excluded as the major cause of this depolarization by experiments in which TRIS was substituted for Na+ in the medium. On the other hand, the decrease in the electrogenic participation of the Na+,K+-pump is apparently one of the causes of RMP decrease during hypogravity, in EDL muscle in particular., O. Tyapkina ... [et al.]., and Obsahuje seznam literatury
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
Resveratrol is a polyphenol found in different plant species and having numerous health-promoting properties in animals and humans. However, its protective action against deleterious effects of ethanol is poo rly elucidated. In the present study, the influence of resveratrol (10 mg/kg/day) on some hormones and metabolic parameters was determined in rats ingesting 10 % ethanol solution for two weeks. Blood levels of insulin, glucagon and adiponectin were affecte d by ethanol, however, resveratrol partially ameliorated these changes. Moreover, in ethanol drinking rats, liver lipid accumulation was increased, whereas resveratrol was capable of reducing liver lipid content, probably due to decrease in fatty acid synt hesis. Resveratrol decreased also blood levels of triglycerides and free fatty acids and reduced γ-glutamyl transferase activity in animals ingesting ethanol. These results show that resveratrol, already at low dose, alleviates hormonal and metabolic changes induced by ethanol in the rat and may be useful in preventing and treating some consequences o f alcohol consumption., K. Szkudelska, M. Deniziak, P. Roś, K. Gwóźdź, T. Szkudelski., and Obsahuje bibliografii
The present review is intended to focus on naturally occurring cytoprotective agents such as resveratrol (trans-3,4’,5- trihydroxystilbene) and other related compounds, probably with similar molecular mechanisms of action and high capacity to find applications in medical fields. Several physiological aspects have been ascribed to resveratrol and similar compounds. Resveratrol, among others, has been recently described as a silent information regulator T1 (SIRT1) activator that increases AMPactivated protein kinase (AMPK) phosphorylation and reduces the oxidative damage biomarkers during aging in laboratory settings. The reports on resveratrol and other SIRT1 activators from various sources are encouraging. The pharmacological strategies for modulation of sirtuins by small molecules through allosteric mechanisms should gain a greater momentum including human research. Resveratrol and resveratrol-like molecules seem to fulfill the requirement of a new horizon in drug research since these molecules cover a growing research means as antioxidants with allosteric mechanism in epigenetic drug targets. However, one should keep in mind the challenges of extrapolation of basic research into clinical results. Overall, the issue of sirtuins in biology and disease provides an insight on therapeutic potentials of sirtuin-based therapeutics and demonstrates the high complexity of drug-targeting these modalities for human applications., H. Farghali, N. Kutinová Canová, N. Lekić., and Obsahuje seznam literatury
The concept of vena contracta space reduction in tricuspid valve position was tested in an animal model. Feasibility of specific artificial obturator body (REMOT) fixed to the right ventricular apex and interacting with tricuspid valve leaflets was evaluated in three different animal studies. Catheter-based technique was used in three series of experiment in 7 sheep. First acute study was designed for evaluation if the screwing mode of guide wire anchoring to the right ventricular apex is feasible for the whole REMOT body fixing. Longer study was aimed to evaluate stability of the REMOT body in desired position when fixing the screwing wire on its both ends (to the right ventricular apex and to the skin in the neck area). X-ray methods and various morphological methods were used. The third acute study was intended to the REMOT body deployment without any fixing wire. In all of 7 sheep the REMOT was successfully inserted into the right heart cavities and then fixed to the ri ght ventricular apex area. When the REMOT was left in situ more than 6 months it was stable, induced adhesion to the tricuspid valve leaflet and was associated with a specific cell invasion. Releasing of the REMOT from the guiding tools was also successfully verified. Deployment of the obturator body in the aim to reduce the tricuspid valve orifice is feasible and well tolerated in the short and longer term animal model. Specific cell colonization including neovascularization of the obturator body was observed., J. Sochman ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The Prague Hereditary Hypercholesterolemic (PHHC) rat is a model of hypercholesterolemia. In previous experiments, it was found to be completely resistant to the development of atherosclerosis. It was assumed that the reverse transport of cholesterol (RCT) might be the reason for this resistance. In this study, RCT was measured in vivo by cholesterol efflux from macrophages to plasma, using previously established methods for RCT in mice (Rader 2003), optimized for measurements in rats. Primary cell culture of macrophages was labeled with 14Ccholesterol and then injected intraperitoneally into rats. Plasma and feces were collected at 24 and 48 h. The plasma 14Ccholesterol levels at both 24 and 48 h were significantly higher in male PHHC rats compared to control Wistar rats. The PHHC rats excreted less 14C-cholesterol in feces in 24 and 48 h compared to Wistar rats. The largest pool of 14C-cholesterol was found in the adipose tissue of PHHC rats and in contrast lower levels of 14Ccholesterol were measured in the liver and muscle tissues of PHHC rats compared with Wistar rats. Increasing release of 14Ccholesterol efflux from macrophages demonstrates accelerated RTC and leads to prevention of atherogenesis in PHHC rats., M. Schmiedtova, M. Heczkova, J. Kovar, I. Kralova Lesna, R. Poledne., and Obsahuje bibliografii
The vessels on the fetal side of the placenta differ from most other vascular beds except the lungs in that they respond to acute hypoxia by vasoconstriction. An essential role of calcium influx in the mechanism of this hypoxic fetoplacental vasoconstriction (HFPV) has been shown previously. That finding does not, however, exclude the possible involvement of other mechanisms of vascular tone regulation. In this study we tested the hypothesis that Rho-kinase-mediated calcium sensitization is involved in HFPV. We used a model of isolated rat placenta dually perfused (from both the maternal and fetal side) with Krebs salt solution saturated with normoxic and hypoxic gas mixture respectively at constant flow rate. Rho-kinase pathway was inhibited by fasudil (10 μM). We found that fasudil reduced basal normoxic fetoplacental vascular resistance and completely prevented HFPV. This suggests that the activity of Rho-kinase signaling pathway is essential for HFPV., P. Kafka, ... [et al.]., and Obsahuje seznam literatury
This study investigated the effects of riboflavin on energy metabolism in hypoxic mice. Kunming mice were fed diets containing riboflavin at doses of 6, 12, 24 and 48 mg/kg, respectively for 2 weeks before exposure to a simulated altitude of 6000 m for 8 h. Changes of riboflavin status and energy metabolism were assessed biochemically. Simultaneously, a 1H nuclear magnetic resonance (NMR) based metabolomic technique was used to track the changes of plasma metabolic profiling. It was found that the content of hepatic riboflavin was decreased and erythrocyte glutathione activation coefficient was elevated significantly under hypoxic condition. Meanwhile, increased plasma pyruvate, lactate, β-hydroxybutyrate and urea, as well as decreased plasma carnitine were observed. Riboflavin supplementation improved riboflavin status remarkably in hypoxic mice and decreased plasma levels of pyruvate, free fatty acids and β-hydroxybutyrate significantly. Plasma carnitine was increased in response to riboflavin supplementation. Results obtained from 1H NMR analysis were basically in line with the data from biochemical assays and remarkable changes in plasma taurine, choline and some other metabolites were also indicated. It was concluded that riboflavin requirement was increased under acute hypoxic condition and riboflavin supplementation was effective in improving energy metabolism in hypoxic mice., Y. P. Wang, J. Y. Wei, J. J. Yang, W. N. Gao, J. Q. Wu, C. J. Guo., and Obsahuje bibliografii
Airway smooth muscle (ASM) me mbrane depolarization through KCl opens L-type voltage dependent Ca 2+ channels (Ca v 1.2); its opening was considered the caus e of KCl contraction. This substance is used to bypass intracellular second messenger pathways. It is now clear that KCl also activates RhoA/Rho kinase (ROCK) pathway. ROCK isoforms are characterized as ROCK1 and ROCK2. Because ROCK1 seems the most abundant isotype in lung, we studied its participation in KCl stimulated bovine ASM. With methyl- β -cyclodextrin (M β CD) we disrupted caveolae, a membrane compartment considered as the RhoA/ROCK assembly site, and found that KCl contraction was reduced to the same extent (~26 %) as Y-27632 (ROCK inhibitor) treated tissues. We confirmed that KCl induces ROCK activation and this effect was annulled by Y-27632 or M β CD. In isolated plasmalemma, ROCK1 was localized in non-caveolar membrane fractions in Western blots from control tissues, but it transferred to caveolae in samples from tissues stimulated with KCl. Ca v 1.2 was found at the non-caveolar membrane fractions in control and M β CD treated tissues. In M β CD treated tissues stimulated with KCl, contraction was abolished by nifedipine; only the response to Ca v 1.2 opening remained as the ROCK component disappeared. Our result s show that, in ASM, the KCl contraction involves the translocation of ROCK1 from non- caveolar to caveolar regions an d that the proper physiological response depends on this translocation., B. Sommer ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy