We recently reported that in vitro Cognac polyphenolic compounds (CPC) induce NO-dependent vasorelaxant effects and stimulate cardiac function. In the present study, we aim to investigate the effect of CPC on both nitric oxide (NO) and superoxide anions (O2-) production in cultured human endothelial cells. In addition, its effect on the bradykinin (BK)-induced NO production was also tested. The role and sources of O2- in the concomitant effect of BK plus CPC were pharmacologically determined. NO and O2- signals were measured using electron paramagnetic resonance technique using specific spin trappings. Both, CPC and BK induced an in crease in NO production in human endothelial cells. The combination of both further enhanced NO release. The capacity of CPC plus BK to increase NO signal was blunted by the NO synthase inhibitor, NG-nitro-L-arginine methyl ester, and was enhanced in the presence either of superoxide dismutase or catalase. Moreover, CPC plus BK response was greater after inhibition of either NADPH oxidase by apocynin or xanthine oxidase by allopurinol but it was not affected by rotenone. CPC did not affect O2- level either alone or after its increase upon lipopolysaccharide treatment. Finally, the capacity of BK alone to increase NO was enhanced either by apocynin or allopurinol. Altogether, these data demonstrate that CPC is able to directly increase NO production without affecting O2- and enhances the BK-induced NO production in human endothelial cells. The data highlight the ability of BK to stimulate not only NADPH oxidase- but also xanthine oxidase-inhibitor sensitive mechanisms that reduce its efficiency in increasing NO either alone or in the presence of CPC. These results bring pharmacological evidence for vascular protection by CPC via its potentiating effect of BK response in terms of endothelial NO release., A. Sall Diallo, M. Sarr, H. A. Mostefai, N. Carusio, M. Pricci, R. Andriantsitohaina., and Obsahuje bibliografii a bibliografické odkazy
The purpose of the present study was to examine whether the level of oxygen uptake (V.o2) at the onset of decrement-load exercise (DLE) is lower than that at the onset of constant-load exercise (CLE), since power output, which is the target of V.o2 response, is decreased in DLE. CLE and DLE were performed under the conditions of moderate and heavy exercise intensities. Before and after these main exercises, previous exercise and post exercise were performed at 20 watts. DEL was started at the same power output as that for CLE and power output was decreased at a rate of 15 watts per min. V.o2 in moderate CLE increased at a fast rate and showed a steady state, while V.o2 in moderate DLE increased and decreased linearly. V.o2 at the increasing phase in DLE was at the same level as that in moderate CLE. V.o2 immediately after moderate DLE was higher than that in the previous exercise by 98±77.5 ml/min. V.o2 in heavy CLE increased rapidly at first and then slowly increased, while V.o2 in heavy DLE increased rapidly, showing a temporal convexity change, and decreased linearly. V.o2 at the increasing phase of heavy DLE was the same level as that in heavy CLE. V.o2 immediately after heavy DLE was significantly higher than that in the previous exercise by 156±131.8 ml/min. Thus, despite the different modes of exercise, V.o2 at the increasing phase in DLE was at the same level as that in CLE due to the effect of the oxygen debt expressed by the higher level of V.o2 at the end of DLE than that in the previous exercise., T. Yano, H. Ogata, R. Matsuura, T. Arimitsu, T. Yunoki., and Obsahuje bibliografii a bibliografické odkazy
a_1 In this study, we have determined power output reached at maximal oxygen uptake during incremental cycling exercise (PI,max) performed at low and at high pedaling rates in nineteen untrained men with various myosin heavy chain composition (MyHC) in the vastus lateralis muscle. On separate days, subjects performed two incremental exercise tests until exhaustion at 60 rev . min-1 and at 120 rev . min-1. In the studied group of subjects PI,max reached during cycling at 60 rev . min-1 was significantly higher (p=0.0001) than that at 120 rev . min-1 (287±29 vs. 215±42 W, respectively for 60 and 120 rev . min-1). For further comparisons, two groups of subjects (n=6, each) were selected according to MyHC composition in the vastus lateralis muscle: group H with higher MyHC II content (56.8±2.79 %) and group L with lower MyHC II content in this muscle (28.6±5.8 %). PI,max reached during cycling performed at 60 rev . min-1 in group H was significantly lower than in group L (p=0.03). However, during cycling at 120 rev . min-1, there was no significant difference in PI,max reached by both groups of subjects (p=0.38). Moreover, oxygen uptake (VO2), blood hydrogen ion [H+], plasma lactate [La-] and ammonia [NH3] concentrations determined at the four highest power outputs completed during the incremental cycling performed at 60 as well as 120 rev . min-1, in the group H were significantly higher than in group L. We have concluded that during an incremental exercise performed at low pedaling rates the subjects with lower content of MyHC II in the vastus lateralis muscle possess greater power generating capabilities than the subjects with higher content of MyHC II. Surprisingly, at high pedaling rate, power generating capabilities in the subjects with higher MyHC II content in the vastus lateralis muscle did not differ from those found in the subjects with lower content of MyHC II in this muscle., a_2 We have concluded that during an incremental exercise performed at low pedaling rates the subjects with lower content of MyHC II in the vastus lateralis muscle possess greater power generating capabilities than the subjects with higher content of MyHC II. Surprisingly, at high pedaling rate, power generating capabilities in the subjects with higher MyHC II content in the vastus lateralis muscle did not differ from those found in the subjects with lower content of MyHC II in this muscle, despite higher blood [H+], [La-] and [NH3] concentrations. This indicates that at high pedaling rates the subjects with higher percentage of MyHC II in the vastus lateralis muscle perform relatively better than the subjects with lower percentage of MyHC II in this muscle., J. Majerczak, Z. Szkutnik, K. Duda, M. Komorowska, I. Kolodziejski, J. Karasinski, J. A. Zoladz., and Obsahuje bibliografii a bibliografické odkazy
The purpose of this study was to examine how oxygen uptake (V.o2) in decrement-load exercise (DLE) is affected by changing rate of decrease in power output. DLE was performed at three different rates of decrease in power output (10, 20 and 30 watts ・min-1: DLE10, DLE20 and DLE30, respectively) from power output corresponding to 90 % of peak V.o2. V.o2 exponentially increased and then decreased, and the rate of its decrease was reduced at low power output. The values of V.o2 in the three DLE tests were not different for the first 2 min despite the difference in power output. The relationship between V.o2 and power output below 50 watts was obtained as a slope to estimate excessive V.o2 (ex-V.o2) above 50 watts. The slopes were 10.0±0.9 for DLE10, 9.9±0.7 for DLE20 and 10.2±1.0 ml ・min-1 ・ watt-1 for DLE30. The difference between V.o2 estimated from the slope and measured V.o2 was defined as ex-V.o2. The peak value of ex-V.o2 for DLE10 (189±116 ml ・min-1) was significantly greater than those for DLE20 and for DLE30 (93±97 and 88±34 ml ・min-1). The difference between V.o2 in DLE and that in incremental-load exercise (ILE) below 50 watts (ΔV.o2) was greater in DLE 30 and smallest in DLE10. There were significant differences in ΔV.o2 among the three DLE tests. The values of ΔV.o2 at 30 watts were 283±152 for DLE10, 413±136 for DLE20 and 483±187 ml ・min-1 for DLE30. Thus, a faster rate of decrease in power output resulted in no change of V.o2 at the onset of DLE, smaller ex-V.o2 and greater ΔV.o2. These results suggest that V.o2 is disposed in parallel in each motor unit released from power output or recruited in DLE., T. Yano, T. Yunoki, R. Matsuura, T. Arimitsu, T. Kimura., and Obsahuje bibliografii a bibliografické odkazy
The aim of this study was to determine whether excessive oxygen uptake (V.o2) occurs not only during exercise but also during recovery after heavy exercise. After previous exercise at zero watts for 4 min, the main exercise was performed for 10 min. Then recovery exercise at zero watts was performed for 10 min. The main exercises were moderate and heavy exercises at exercise intensities of 40 % and 70 % of peak V.o2, respectively. V.o2 kinetics above zero watts was obtained by subtracting V.o2 at zero watts of previous exercise (ΔV.o2). ΔV.o2 in moderate exercise was multiplied by the ratio of power output performed in moderate and heavy exercises so as to estimate the ΔV.o2 applicable to heavy exercise. The difference between ΔV.o2 in heavy exercise and ΔV.o2 estimated from the value of moderate exercise was obtained. The obtained V.o2 was defined as excessive V.o2. The time constant of excessive V.o2 during exercise (1.88±0.70 min) was significantly shorter than that during recovery (9.61±6.92 min). Thus, there was excessive V.o2 during recovery from heavy exercise, suggesting that O2/ATP ratio becomes high after a time delay in heavy exercise and the high ratio continues until recovery., T. Zano, T. Yunoki, R. Matsuura, T. Arimitsu, T. Kimura., and Obsahuje bibliografii a bibliografické odkazy
Pb(Zr,Ti)O3 (PZT) is a ferroelectric material interesting for its high dielectric constant and piezoelectric response. PZT thin films can be prepared by various methods, e.g. pulsed laser deposition, chemical vapor deposition, sol-gel and, most frequently, sputtering. Though the magnetron sputtering is used more frequently, PZT thin films can be prepared also by ion-beam sputtering (IBS). In this paper we study the deposition process of PZT thin films in our IBS system with a possibility of ion-beam assisted deposition (IBAD), which has the advantage that more energy can be added to the growing layer. We focus here mainly on the influence of the oxygen flux during the deposition on the quality of the resulting layers. We compare the samples grown on the silicon substrate with and without an intermediate Ti seeding layer. and Olovo-zirkonát-titanát Pb(Zr,Ti)O3 (PZT) je ferroelektrický materiál zajímavý pro svou vysokou dielektrickou konstantu a silnou piezoelektrickou odezvu. Tenké PZT vrstvy mohou být připraveny různými metodami, např. pulzní laserovou depozicí, chemickým nanášením par, metodou sol-gel a nejčastěji naprašováním. I když se magnetronové naprašování používá častěji, mohou být tenké PZT vrstvy připraveny i naprašováním iontovým svazkem (IBS). V tomto článku studujeme depoziční proces tenkých PZT vrstev v našem systému depozice iontovým svazkem s možností asistenčního iontového svazku (IBAD). Soustředíme se zejména na ovlivnění kvality výsledných vrstev množstvím připouštěného kyslíku během depozice. Porovnáváme vzorky pěstované na křemíkovém substrátu s Ti mezivrstvou nebo bez ní.
To test whether macrophages can play any role in hypoxic pulmonary vasoconstriction, we tested the in vitro response of rings from small pulmonary arteries to the activation of macrophages by FMLP, a substance stimulating predominantly membrane-bound NADPH oxidase. A small vessel myograph was used to measure the responses of rings from small pulmonary arteries (300-400 μ m) isolated from rat lungs. Rings from 5 rats were placed into both chambers of the myograph. The vessels were stabilized for 40 min and then normalized by automatic stretching to a wall tension equivalent to the intravascular pressure 30 mm Hg. At the start of each experiment, vessels were exposed to 80 mM K + to obtain maximal contractile response, which was used to normalize subsequent contractile responses. 2x10 6 viable macrophages, obtained by peritoneal lavage, were added into one chamber, then 5 μ M FMLP was administrated to both chambers and the tension measurement was started. The hydrogen peroxide concentration produced by stimulated macrophages was measured luminometrically. The concentrations of H 2 O 2 in specimens from chambers containing activated macrophages rose from 3.5±1.5 nM to 110±28 nM within 25 min of stimulation, while FMLP itself didn’t increase the H 2 O 2 concentration from the baseline value (4.5±3 nM) in samples from control chambers. After FMLP administration, the tension of the vessel rings in the presence of macrophages reached 0.23±0.07 of maximal contractile response, it did not change in controls. The additi on of ROS scavenger 4-hydroxy- TEMPO blocked the contractile response to the activation of macrophages. We conclude that the activation of macrophages stimulates the contraction of small pulmonary arteries and that this contraction is probably mediated by reactive oxygen species., M. Žaloudíková, J. Herget, M. Vízek., and Obsahuje bibliografii a bibliografické odkazy
The changes in thermoluminescence (TL) signals induced by short-term ozone exposure of leaves are characterized by a down-shift of the peak-temperature of the TLB-band and an increase of a TL band at 55°C. We investigated the relationship of these changes to photosystem 2 (PS2) photochemistry. The changes were not only detectable in the presence of ozone, but also after irradiation of dark-adapted leaves and after aging of irradiated detached leaf segments. The opposite effect on TL, an up-shift of the peak-temperature of the B-band and the decrease of the intensity of the band at 55°C were found after infiltration of leaves with nigericin, antimycin A, and diphenyleneiodonium chloride (DPI). Propyl gallate down-shifted the peak-temperature of the B-band. 2,5-dimethyl-1,4-benzoquinone up-shifted the peak-temperature of the B-band and decreased the intensity of the 55°C band. The intensity of the 55°C band did not change significantly in the presence of oxygen in comparison to that in nitrogen atmosphere. It decreased with time of dark adaptation (50% intensity was observed after 3 h of dark adaptation at room temperature), however, it was reactivated to its initial value (at 5 min of dark adaptation) after 1 single-turnover flash. The 55°C band was not significantly changed in the presence of DCMU. Thus the ozone-induced band at 55°C is assigned to charge recombination in PS2. Changes in the electron transport chain at the acceptor side of PS2, probably related to the cyclic electron transport around photosystem 1 and/or chlororespiration, could play an important role in the increase of the 55°C band and the down-shift of the B-band. The changes at the acceptor side indicated by TL can be an ex pression of a physiological regulatory mechanism functional under stress conditions. and J. Skotnica ... [et al.].
V práci je prezentovaná problematika tvorby vol'ných radikálov kyslíka, ich elektrónovej štruktúry, vlastností a metódy detekcie. Pozornosť je venovaná poškodzujúcemu účinku vol'ných radikálov na nukleové kyseliny, proteíny a biologické membrány., The article is dealing with the topic of oxygen-containing free radicals, their electronic structure, properties and methods of detection. Attention is paid to chemical and biochemical aspects of these free radicals, i.e., the sources of their generation, the metal-mediated formation of the reactive species and the damage to lipids, proteins and nucleic acids initiated by them., Klaudia Jomová, Ľubomír Zelenický, Vlasta Brezová, Marián Valko., and Obsahuje bibliografii