Visfatin was originally described as an adipokine with insulin mimetic effects. Recently, it was found that visfatin is identical with the Nampt (nicotinamide phosphoribosyltransferase) gene that codes for an intra- and extracellular NAD biosynthetic enzyme and is predominantly expressed outside the adipose tissue. In the current study, we found strong protein and mRNA expression of visfatin in rat heart, liver, kidney, and muscle, while the expression of visfatin in visceral fat was significantly lower and undetectable in subcutaneous fat. The insulin-mimetic effects of visfatin (extracellular form of Nampt or eNampt) are controversial and even less is known about autocrine effects of visfatin (intracellular form of Nampt or iNampt). Since liver plays a major role in glucose metabolism, we studied visfatin effects on insulin-stimulated cellular glucose uptake in Fao rat hepatocytes using RNA interference (RNAi). RNAi-mediated downregulation of visfatin expression in Fao cells was associated with significantly reduced NAD biosynthesis (0.3±0.01 vs. 0.5±0.01 mmol/h/g, P<0.05) and with significantly decreased incremental glucose uptake after stimulation with insulin when compared to controls with normal expression of visfatin (0.6±0.2 vs. 2.2±0.5 nnmol/g/2 h, P=0.02). These results provide evidence that visfatin exhibits important autocrine effects on sensitivity of liver cells to insulin action possibly through its effects on NAD biosynthesis., V. Škop ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The astrogeodetic method of detailed geoid determination need astronomical observations of longitude and latitude. Together with GPS observations it may be used to vertical deflections determination. In the article the portable system for automatic determination of astrogeodetic vertical deflection components developed at AGH University of Science and Technology is described. The design, main error sources, and preliminary results of the test measurements are presented., Jacek Kudrys., and Obsahuje bibliografii
The known vertical deflection values can be utilised to increase geoid’s accuracy. One of the methods of vertical deflection components (ξ, η) determination is to compare astronomic and geodetic coordinates. Presently it is easy possible to obtain geodetic coordinates with high accuracy from GPS observation. In the article the methods of astronomical CCD observation with aid of two different optical systems are discussed. Project realisation is in preliminary stage and there are no results available yet., Jacek Kudrys., and Obsahuje bibliografické odkazy
Automobily na vodíkový pohon ponúkajú mnoho výhod v porovnaní s automobilom s tradičným spal'ovacím motorom. Ekologicky čistá a tichá prevádzka spojená s vysokou účinnosťou vodíkového palivového článku (VPČ) z nich robí atraktívnych kandidátov na automobily budúcnosti. V tomto článku stručne rozoberám históriu a vývoj VPČ, jeho dizajn ako aj problémy, ktoré je nutné odstranit aby mohla byť táto technológia uvedená v masovom rozsahu do praxe., Fuel cell (FC) cars offer many advantages when compared to cars with combustion engines. Ecologically clean, noise-free and their high fuel efficiency makes fuel cell powered cars attractive candidates for future automobiles. In this paper I briefly discuss the history, development and design of the FC as well as the problems still plaguing this technology and preventing its deployment on the mass scale., Vladimír Komanický., and Obsahuje seznam literatury