18 (2012) Scientific papers, Series A
https://hdl.handle.net/10195/75369
2024-03-28T21:43:32ZDetermination 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)
https://hdl.handle.net/10195/75384
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)
Bajerová, Petra; Týčová, Kateřina; Eisner, Aleš; Adam, Martin; Sedlák, Miloš; Ventura, Karel
New 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.
2012-01-01T00:00:00ZAn assay of 4-hydroxy-trans-2-nonenal in human seminal plasma using a high-performance liquid chromatography with fluorescence detection
https://hdl.handle.net/10195/75383
An assay of 4-hydroxy-trans-2-nonenal in human seminal plasma using a high-performance liquid chromatography with fluorescence detection
Drábková, Petra; Martínková, Jiřina; Míková, Veronika; Štramová, Xenie; Kanďár, Roman
A 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 %.
2012-01-01T00:00:00ZInhibitory effect of N–ethylmaleimide in two types of glutathione reductases
https://hdl.handle.net/10195/75382
Inhibitory effect of N–ethylmaleimide in two types of glutathione reductases
Nýdlová, Erika; Roušar, Tomáš
Glutathione 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.
2012-01-01T00:00:00ZBiofilm production by Staphylococcus aureus strains isolated from cystic fibrosin patients
https://hdl.handle.net/10195/75381
Biofilm production by Staphylococcus aureus strains isolated from cystic fibrosin patients
Kukla, Rudolf; Paterová, Pavla; Mazurová, Jaroslava
Cystic 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.
2012-01-01T00:00:00Z