Leaf senescence can be induced by numerous factors. In order to explore the relationship between root respiration and leaf senescence, we utilized different types of phloem girdling to control the root respiration of Alhagi sparsifolia and its physiological response. Our results showed that both girdling and inhibition of root respiration led to a decline of stomatal conductance, photosynthesis, transpiration rate, chlorophyll (Chl) a, Chl b, carotenoid (Car) content, Chl a/b, Chl/Car, water potential, and Chl a fluorescence, as well as to an increase of abscisic acid (ABA), proline, and malondialdehyde content in leaves and to upregulation of senescence-associated gene expression. Our present work implied that both inhibition of root respiration and girdling can induce leaf senescence. In comparison with phloem girdling, the leaf senescence caused by inhibition of root respiration was less significant. The reason for girdling-induced senescence was ABA and carbohydrate accumulation. Senescence induced by inhibition of root respiration occurred due to leaf water stress resulting from inhibition of water absorption., G.-L. Tang, X.-Y. Li, L.-S. Lin, Y. Hu, F.-J. Zeng., and Obsahuje seznam literatury
The detailed mechanisms determining the course of congestive heart failure (CHF) and associated renal dysfunction remain unclear. In a volume overload model of CHF induced by creation of aorto- caval fistula (ACF) in Hannover Sprague -Dawley (HanSD) rats we explored the putative pathogenetic contribution of epoxyeicosatrienoic acids (EETs), active products of CYP -450 dependent epoxygenase pathway of arachidonic acid metabolism, and compared it with the role of the renin-angiotensin system (RAS). Chronic treatment with cis -4-[4-(3-adamantan -1-yl- ureido) cyclohexyloxy]benzoic acid (c-AUCB, 3 mg /l in drinking water), an inhibitor of soluble epoxide hydrolase (sEH) which normally degrades EETs, increased intrarenal and m yocardial EETs to levels observed in sham -operated HanSD rats, but did not improve the survival or renal function impairment. In contrast, chronic angiotensin -converting enzyme inhibition (ACEi, trandolapril, 6 mg /l in drinking water) increased renal blood flow, fractional sodium excretion and markedly improved survival, without affecting left ventricular structure and performance. Hence, renal dysfunction rather than cardiac remodeling determines long-term mortality in advanced stage of CHF due to volume o verload. Strong protective actions of ACEi were associated with suppression of the vasoconstrictor/sodium retaining axis and activation of vasodilatory/natriuretic axis of the renin -angiotensin system in the circulating blood and kidney tissue., L. Červenka, V. Melenovský, Z. Husková, A. Sporková, M. Bürgelová, P. Škaroupková, S. H. Hwang, B. D. Hammock, J. D. Imig, J. Sadowski., and Obsahuje bibliografii
In the horse, the inflammation response to various pathologies (intestinal strangulations, laminitis, etc.) involves an excessive stimulation of the polymorphonuclear neutrophils releasing reactive oxygen species (ROS) and myeloperoxidase (MPO). The aim of the present work was to study the effect of natural polyphenols, curcumin oids and tetrahydrocurcuminoids (THC) on isolated stimulated equine neutrophils and on the activity of purified MPO. The ROS production and the release of MPO by activated neutrophils were measured by chemiluminescence and ELISA techniques, respectively. The activity of purified MPO was measured by studying its nitration, chlorination or oxidation capacity and by using an original method called SIEFED allowing the study of drug interaction with the enzyme without interferences of the medium. Curcuminoids and THC had dose-dependent inhibitory effects on ROS production and MPO release by activated neutrophils and on purified MPO activity. We suggest that the higher efficacy of curcuminoids versus THC could be explained, at least partially, by its chemical structure: the conjugated double bounds and the plane structure of curcuminoids made easier the neutralization of the radical species generated by activated neutrophils and the interaction of the drug with the active site of MPO. These inhibitory effects of curcuminoids on the oxidant activity of equine neutrophils and on MPO activity open therapeutic perspectives in equine pathologies with excessive inflammatory reactions., T. Franck, S. Kohnen, S. Grulke, P. Neven, Y. Goutman, F. Peters, B. Pirotte, G. Deby-Dupont, D. Serteyn., and Obsahuje bibliografii a bibliografické odkazy
We analyzed the effect of FK 506 on the production of nitric oxide by macrophages. Isolated rat peritoneal macrophages were cultured for 24 h with or without lipopolysaccharide (LPS) (5 µg/ml) and in the absence or presence of FK 506 (0.1 and 1 µg/ml). The concentration of NO2- in culture supernatants was taken as a measure of nitric oxide production. FK 506 (0.1 and 1 µg/ml) reduced the LPS-induced increase of NO2- levels by 68 % and 81 %, respectively. The impact of cyclosporin A (CsA) was studied in order to compare their effects. CsA (0.1 and 1 µg/ml) decreased the levels of nitrites by 39 % and 69 %, respectively. The results obtained suggest that both immunosuppressive drugs exhibit a dose-dependent inhibitory effect on nitric oxide production and that FK 506 is a more potent agent than CsA in this respect., P. Střeštíková, B. Otová, M. Filipec, H. Farghali., and Obsahuje bibliografii
Metformin is widely used in the treatment of Type 2 diabetes, however, mechanisms of its antihyperglycemic effect were not yet fully elucidated. Complex I of mitochondrial respiration chain is considered as one of the possible targets of metformin action. In this paper, we present data indicating that the inhibitory effect of metformin can be tested also in liver homogenate. Contrary to previous findings on hepatocytes or mitochondria under our experimental conditions, lower metformin concentrations and shorter time of preincubation give significant inhibitory effects. These conditions enable to study the mechanism of the inhibitory effect of metformin in small samples of biological material (50-100 mg wet weight) and compare more experimental groups of animals because isolation of mitochonria is unnecessary., E. Páleníčková ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Using high-resolution oxygraphy, we tested the changes of various parameters characterizing the mitochondrial energy provision system that were induced by peroxidative damage. In the presence of succinate as respiratory substrate, 3 mM t-butyl hydroperoxide increased respiration in the absence of ADP, which indicated partial uncoupling of oxidative phosphorylation. Low activity of coupled respiration was still maintained as indicated by the ADP-activated and oligomycin-inhibited respiration. However, during the incubation the phosphorylative capacity decreased as indicated by the continuous decrease of the mitochondrial membrane potential. Under these experimental conditions the maximum capacity of the succinate oxidase system was inhibited by 50 % in comparison with values obtained in the absence of t-butyl hydroperoxide. Our data thus indicate that the oxygraphic evaluation of mitochondrial function represents a useful tool for evaluation of changes participating in peroxidative damage of cell energy metabolism., P. Křiváková, A. Lábajová, Z. Červinková, Z. Drahota., and Obsahuje bibliografii a bibliografické odkazy
In contrast to the well-established anti-apoptotic effect of Bcl-2 protein, we have recently demonstrated that Bcl-2 overexpression by vaccinia virus causes apoptosis in BSC-40 cells, while it prevents apoptosis in HeLa G cells. Given the key role of mitochondria in the process of apoptosis, we focused on effects of Bcl-2 expression on mitochondrial energetics of these two cell lines. In this study we present data indicating that BSC-40 cells derive their ATP mainly from oxidative phosphorylation whereas HeLa G cells from glycolysis. More importantly, we show that in both cell lines, Bcl-2 inhibits mitochondrial respiration and causes a decrease of the ATP/ADP ratio. However, it appears that BSC-40 cells cannot sustain this decrease and die, while HeLa G cells survive, being adapted to the low ratio of ATP/ADP maintained by glycolysis. Based on this observation, we propose that the outcome of Bcl-2 expression is determined by the type of cellular ATP synthesis, namely that Bcl-2 causes apoptosis in cells relying on oxidative phosphorylation., M. Vrbacký, J. Krijt, Z. Drahota, Z. Mělková., and Obsahuje bibliografii
Úvod: Inhibitory protonové pumpy (PPI) jsou léky často užívané pro široké spektrum onemocnění horního trávicího traktu. U mnoha pacientů je léčba potřebná chronicky. Ačkoli je dlouhodobé podávání považováno za bezpečné, je v posledních letech věnována široká pozornost možnému zvýšenému výskytu fraktur u uživatelů inhibitorů protonové pumpy, což se promítá i do informací poskytovaných v příbalové dokumentaci léčiv. Cílem práce je poskytnutí přehledu o aktuálních poznatcích v této oblasti a analýza podkladů, na jejichž základě je informace o zvýšeném riziku založena. Výsledky: Základní informace o zvýšeném riziku fraktur u osob užívajících inhibitory protonové pumpy pochází z retrospektivních epidemiologických studií. Dalším zdrojem jsou studie, u nichž byl jako vedlejší cíl sledován vliv inhibitorů protonové pumpy na efekt léčby osteoporózy pomocí bisfosfonátů. Přímá pozorování efektu inhibitorů protonové pumpy na vstřebávání vápníku a vlivu na kosti při hodnocení denzitometrií jsou ojedinělá. Závěr: Jednoznačné určení rizika ovlivnění kostí dle dosavadních pozorování není možné, zvláště při významné polymorbiditě a polypragmazii řady uživatelů inhibitorů protonové pumpy. Žádná práce dosud nehodnotila výskyt rizikových událostí v závislosti na indikaci pro dlouhodobou léčbu. Rutinní sledování kostních parametrů při léčbě PPI není doporučeno. Základem bezpečnosti je správná indikace a omezení nadbytečné preskripce léků., Introduction: The proton pump inhibitors are commonly used drugs for the treatment of the digestive disorders. Many patients require long-term maintenance therapy. The prolonged acid inhibition is considered to be safe, but recently, the attention has been paid to the possible effects on the bone metabolism and the higher incidence of the fractures in patients using the PPIs. The aim of this work is to give a complex overview on the topic and analyse the source of information about the increased risk of the fractures. Results: Several epidemiological studies describe the incidence of the fractures in the patients with PPIs. Further articles, mainly describing the effect of the bisphosphonate therapy for the osteoporosis, also track the PPI effects. The studies dealing with the articles on densitometry targeting on the effect of the PPIs on the bone metabolism are rare. Conclusion: It is not possible to unequivocally determinate the risks of the long term PPI therapy on bone based on the existing studies due to the heterogenous populations, multimorbidity of the patients and the concurrent medication. Untill now, no study has evaluated the incidence of the risk events based on the indication of the long-term therapy. Routine monitoring of the bone parameters during the PPI therapy is not recommended. The safety of the long-term PPI therapy should be based on the clear indication of the prescription., and Markéta Ječmenová, Radek Kroupa
We consider the class H0 of sense-preserving harmonic functions f = h + \bar g defined in the unit disk |z| < 1 and normalized so that h(0) = 0 = h′(0) − 1 and g(0) = 0 = g′(0), where h and g are analytic in the unit disk. In the first part of the article we present two classes PH0(α) and GH0(β) of functions from H0 and show that if f \in PH0(α) and F \in GH0(β), then the harmonic convolution is a univalent and close-to-convex harmonic function in the unit disk provided certain conditions for parameters α and β are satisfied. In the second part we study the harmonic sections (partial sums) {s_{n,n}}\left( f \right)\left( z \right) = {s_n}\left( h \right)\left( z \right) + \overline {{s_n}\left( g \right)\left( z \right)} , where f = h + \bar g \in H0, sn(h) and sn(g) denote the n-th partial sums of h and g, respectively. We prove, among others, that if f = h + \bar g \in H0 is a univalent harmonic convex mapping, then sn,n(f) is univalent and close-to-convex in the disk |z| < 1/4 for n ≥ 2, and sn,n(f) is also convex in the disk |z| < 1/4 for n ≥ 2 and n ≠ 3. Moreover, we show that the section s3,3(f) of f \in CH0 is not convex in the disk |z| < 1/4 but it is convex in a smaller disk., Liulan Li, Saminathan Ponnusamy., and Obsahuje seznam literatury