18 (2012) Scientific papers, Series A
Permanentní URI k tomuto záznamuhttps://hdl.handle.net/10195/75369
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Článek Otevřený přístup peer-reviewedpublished Determination of amphotericin B in rat blood plasma. Comparison of antifungal activity and pharmacokinetics profile of conventional amphotericin B and its conjugate with poly(ethylene glycol)(University of Pardubice, 2012) Bajerová, Petra; Týčová, Kateřina; Eisner, Aleš; Adam, Martin; Sedlák, Miloš; Ventura, KarelNew intravenous non-covalent conjugate of amphotericin B (AMB)-poly(ethylene glycol)(PEG) (M = 10 000 g mol–1) is described. This well water soluble conjugate contains 4 % (w/w) free AMB. A simple and sensitive HPLC-UV method was developed and validated for the quantification of free amphotericin B in rat plasma. A simple mobile phase consisting of 10 mM ammonium acetate (pH 3.60) and acetonitrile (56:44, v/v) was pumped at a flow rate of 0.3 ml min–1 through a reverse phase column maintained at 30 °C. Rifampicin was used as an internal standard (IS). Rapid sample preparation involved the addition of 500 µl acetonitrile-methanol mixture and 10 µl IS to 200 µl plasma to precipitate plasma proteins. Supernatant was evaporated to dryness under the stream of nitrogen and dissolved in 125 µl of the mobile phase and injected onto column. The procedures were validated within the linear concentration range from 0.06 to 2.5 µg ml–1 with good reproducibility and linear response (r2 = 0.9988). The method described is cost-effective and has necessary accuracy and precision for the rapid quantitative determination of AMB in rat plasma. A two-compartment model described the plasma drug concentration-time profiles.Článek Otevřený přístup peer-reviewedpublished An assay of 4-hydroxy-trans-2-nonenal in human seminal plasma using a high-performance liquid chromatography with fluorescence detection(University of Pardubice, 2012) Drábková, Petra; Martínková, Jiřina; Míková, Veronika; Štramová, Xenie; Kanďár, RomanA method is described for the determination of 4-hydroxy-trans-2-nonenal in human seminal plasma. Semen samples were obtained from male partners of couples presenting for a fertility evaluation. After liquefaction, the samples were centrifuged and the seminal plasma was stored at –80 °C. 4-Hydroxy-trans-2- nonenal was derivatized with 1,3-cyclohexanedione to generate the fluorescent alkyl acridine derivative. After derivatization, seminal plasma proteins were precipitated with cold perchloric acid, and the supernatant was injected into the HPLC system. The separation was realized on an analytical reversed-phase column with fluorescence detection. The mixture of ethanol and deionized water was used as the mobile phase. The intra-assay coefficients of variation were below 10 %. Quantitative recoveries from spiked seminal plasma were between 62.0 and 81.0 %.Článek Otevřený přístup peer-reviewedpublished Inhibitory effect of N–ethylmaleimide in two types of glutathione reductases(University of Pardubice, 2012) Nýdlová, Erika; Roušar, TomášGlutathione reductase (GR) is a key enzyme of glutathione metabolism. This enzyme catalyzes the NADPH-dependent reduction of glutathione disulfide to a reduced form. The aim of the described study was to estimate an enzyme inhibition in two types of glutathione reductases (human and yeast) through Nethylmaleimide (NEM). The glutathione reductase activity was determined by the spectrophotometric method based on the measurement of an absorbance decline (λ = 340 nm) due to oxidation of NADPH. Interestingly, it was found that the presence of 100 :M NEM had no effect in the two glutathione reductases. The inhibitory effect was proved in higher concentrations of N-ethylmaleimide; however, neither 2 mM NEM was able to diminish GR activity. The enzyme activity was reduced in both GRs; the human GR was inhibited by 15 % and 37 % in the presence of 1 mM and 2 mM NEM, respectively; the yeast GR was inhibited at the same concentrations of N-ethylmaleimide by 16 % and 35 %, respectively. We assessed NEM-induced inhibition of the enzyme activity in the presence of 1 mM GSSG (glutathione disulfide) where both GRs were inhibited to a larger extent than in 9 mM GSSG. On the other hand, if glutathione reductase was incubated with NADPH, followed by addition of NEM, the enzyme activity disappeared to a much higher extent. After 2 minutes of incubation with NADPH, the activity of yeast glutathione reductase was inhibited by 70 % and 100 % in the presence of 0.1 mM and 1 mM NEM, respectively.Článek Otevřený přístup peer-reviewedpublished Biofilm production by Staphylococcus aureus strains isolated from cystic fibrosin patients(University of Pardubice, 2012) Kukla, Rudolf; Paterová, Pavla; Mazurová, JaroslavaCystic fibrosis is a serious genetic disorder affecting respiratory, gastrointestinal and genital tracts. The most common causes of health status deterioration of patients with cystic fibrosis are still considered to be bacterial infections. Staphylococcus aureus is one of the most common pathogens isolated from the air passages of these patients. The purpose of our study was to determine the ability and intensity of the biofilm production by 59 of Staphylococcus aureus strains isolated from the air passages of patients with cystic fibrosis in the Cystic fibrosis center at the University Hospital Hradec Kralové. We also evaluated biofilm production and its intensity in 59 Staphylococcus aureus strains isolated from the air passages of control group patients. The control group was formed by patients with nosocomial pneumonia hospitalized in the University Hospital. For assessing the biofilm production, we used modified microtiter-plate test by Christensen. We divided the intensity of biofilm production into four categories according to the measured optical density — negative, weak, medium and strong. Out of total 59 Staphylococcus aureus strains isolated from the air passages of cystic fibrosis patients 45 (77.2 %) strains produced biofilm in various degrees: 21 (35.6 %) weakly, 6 (10.2 %) medium and 18 (30.5 %) strongly. Similar results were determined for strains isolated from control group: 22 (37.3 %) weak, 13 (22.0 %) medium and 9 (15.3 %) strong biofilm producing strains. We found no statistically significant difference in the biofilm formation between both groups of Staphylococcus aureus strains.Článek Otevřený přístup peer-reviewedpublished Interpretation of Tool–Narayanaswamy–Moynihan relaxation parameters(University of Pardubice, 2012) Svoboda, Roman; Málek, JiříDifferential scanning calorimetry (DSC) measurements were used to study enthalpic structural relaxation in selenide glasses. The examined compositions were, apart from pure Se, the following Se(100–y)Tey (for y = 0.1, 0.2 and 0.3), GeySe(100–y) (for y = 0.02, 0.04, 0.06, 0.08, 0.10 and 0.15) and AsySe(100–y)Tey (for y = 0.02, 0.04, 0.06, 0.08 and 0.10). Based on the results of fitting and non-fitting methods, relaxation behavior of these glasses was described in terms of the Tool–Narayanaswamy–Moynihan (TNM) model. The TNM model parameters as well as their change with respect to both increasing content of dopant in Se matrix within each chalcogenide system and different structural units employed in the respective systems were discussed. A unique conception was suggested, introducing a connection between the values of TNM parameters and respective molecular structures and their changes during structural relaxation. By such qualitative interpretation, the main disadvantage of phenomenological models may be, at least partially, overcome.Článek Otevřený přístup peer-reviewedpublished Deconvolution of complex crystallization processes: Amorphous selenium(University of Pardubice, 2012) Svoboda, Roman; Málek, JiříCrystallization behavior of the selenium glass was studied by means of the differential scanning calorimetry under non-isothermal conditions. Two new approaches to the evaluation of crystallization kinetics — advanced interpretation of characteristic kinetic functions and modified Fraser–Suzuki deconvolution — were applied. The determination of kinetic parameters in the dependence on particle size can provide an extensive amount of information about the nature of the involved surface and bulk crystallization mechanisms. Based on these information, the deconvolution in terms of the Johnson–Mehl–Avrami process was performed, separating the two mechanisms. The results not only both, qualitatively and quantitatively, describe the crystallization process in glassy selenium but also explain various data from literature on this topic. Introduced deconvolution may represent a new approach to gaining information about complex crystallization processes for numerous material science applications.Článek Otevřený přístup peer-reviewedpublished Mg/Al mixed oxides: Preparation, properties and catalytic activity in transesterification of rapeseed oil(University of Pardubice, 2012) Kutálek, Petr; Kocík, Jaroslav; Hájek, Martin; Smoláková, Lucie; Čapek, LiborThis paper reviews the preparation, physicochemical properties and application of Mg/Al mixed oxides. Attention is focused on the activity of Mg/Al mixed oxides in transesterification of rapeseed oil. The mixed oxides were prepared from hydrotalcites by calcination and were characterized by XRD, FTIR and AAS. The aim of work was to study the effect of Mg/Al mixed oxides properties such as Mg/Al mass ratio (2-4), the temperature of calcination (450-1000 °C), time of calcination (4-17 h) and post-treatment rehydration of mixed oxides on the activity of Mg/Al catalysts in the transesterification reaction. The results show that the highest catalytic activity was observed for Mg/Al catalysts with Mg/Al mass ratio of 3, calcination temperature of 450 °C, time of calcination of 8 hours and rehydration by water. The leaching of magnesium to liquid phase was also determined and was always less than 0.1 wt. % — the catalyst was stable.Článek Otevřený přístup peer-reviewedpublished Colour possibilities of rare earth orthoferrite pigments(University of Pardubice, 2012) Dohnalová, Žaneta; Vontorčíková, Markéta; Šulcová, PetraThe paper deals with the preparation of the inorganic pigments of general formula RE0.98Ca0.02FeO3, where RE = La, Gd, Lu, Tm, Yb and Ho. The pigments were prepared by the conventional ceramic method, i.e. solid state reaction. As initial components were used Ln2O3, CaCO3 and two sources of Fe components, either Fe2O3 or FeOOH. The reaction mixtures were heated at the temperatures of 800, 900 and 1000 °C. The prepared pigments were applied to an organic binding system and their colour properties evaluated by measuring reflectance in the visible region of light. The most interesting colour properties were obtained by the preparation of the sample Lu0.98Ca0.02FeO3. This pigment was prepared by the calcination of the reaction mixture containing FeOOH and mineralizer LiF at the temperature of 900 °C. Generally, the mineralizer LiF affects the colour properties of all the pigments most significantly.Článek Otevřený přístup peer-reviewedpublished Preparation of functional PET fabric/polypyrrole composite(University of Pardubice, 2012) Šafářová, Veronika; Grégr, Jan; Martínek, MichalConducting and electromagnetic shielding poly(ethylene terephthalate) (PET)/ polypyrrole (PPy) composites were synthesized by in-situ chemical polymerization of pyrrole in the presence of PET fabrics. The effects of preparation conditions on the characteristics of the composite, such as surface morphology, electrical conductivity and electromagnetic shielding efficiency were studied. The synthesized polymer composites were characterized by surface and volume resistivity, EMI shielding and SEM techniques. The most suitable medium, from the point of view of the lowest electrical volume and surface resistivity, the highest electromagnetic shielding efficiency and resultant the highest PPy content of composite fabric, was observed to be aqueous ferric chloride solution with PTSA, non-oxidizing transient tosylates and the pyrrole concentrations of 0.2 vol. %.Článek Otevřený přístup peer-reviewedpublished Influence of shelf-life stability on antimicrobial efficiency of aqueous acrylic dispersion containig nano oxides and organic biocide(University of Pardubice, 2012) Jašková, Veronika; Hochmannová, Libuše; Vytřasová, Jarmila; Kalendová, AndréaAntimicrobial paints were formulated based on various nano particles of zinc oxide and organic biocide. The aqueous acrylic dispersion was used as a binder for this system. A control paint without nanoparticles was formulated. The antimicrobial ability, shelf-life stability and photoactivity were assumed in these paints based on nano zinc oxide with organic biocide. It is possible to observe the photoactivity thanks to a change in organic dyes due to oxidative-reductive reaction. The agar dilution method was used for a test of the antimicrobial ability. The Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were chosen as test bacteria. A great antibacterial inhibition of Escherichia coli and Staphylococcus aureus sis exhibited both coatings, and they are antimicrobially active after 12 months of shelf stability.