Obtained benzimidazole derivatives, our next synthesized heterocyclic compounds, belong to a new group of chemical bondings with potential anticancer properties (Błaszczak-Świątkiewicz & Mikiciuk-Olasik, 2006, J Liguid Chrom Rel Tech 29: 2367-2385; Błaszczak-Świątkiewicz & Mikiciuk-Olasik, 2008, Wiad Chem 62: 11-12, in Polish; Błaszczak-Świątkiewicz & Mikiciuk-Olasik, 2011, J Liguid Chrom Rel Tech 34: 1901-1912). We used HPLC analysis to determine stability of these compounds in 0.2% DMSO (dimethyl sulfoxide). Optimisation of the chromatographic system and validation of the established analytical method were performed. Reversed phases (RP-18) and a 1:1 mixture of acetate buffer (pH 4.5) and acetonitrile as a mobile phase were used for all the analysed compounds at a flow rate 1.0 mL/min. The eluted compounds were monitored using a UV detector, the wavelength was specific for compounds 6 and 9 and compounds 7 and 10. The retention time was specific for all four compounds. The used method was found to have linearity in the concentration range of (0.1 mg/mL-0.1 μg/mL) with a correlation coefficient not less than r(2)=0.9995. Statistical validation of the method proved it to be a simple, highly precise and accurate way to determine the stability of benzimidazole derivatives in 0.2% DMSO. The recoveries of all four compounds examined were in the range 99.24-100.00%. The developed HPLC analysis revealed that the compounds studied remain homogeneous in 0.2% DMSO for up to 96 h and that the analysed N-oxide benzimidazole derivatives do not disintegrate into their analogues - benzimidazole derivatives. Compounds 8, 6 and 9 exhibit the best cytotoxic properties under normoxic conditions when tested against cells of human malignant melanoma WM 115.
The aim of this study was to describe the mechanical features of homogeneous and layered chitosan (Ch) and fibrin–chitosan (Fb–Ch) membranes as well the kinetics of transforming growth factor beta‐1 (TGF‐β1) release from five types of polymer carriers. Composites in the form of a film containing physiologically clotted fibrin (Fb) and microcrystalline chitosan (MCCh) were prepared and then crosslinked with calcium chloride. The films were characterized by Infrared (IR) spectroscopy, mechanical tests (film thickness, maximal tensile force, breaking strength, and elongation at break), and SEM images. The results reveal that Ch film demonstrates higher efficiency in binding TGF‐β1 and, at the same time, is less effective in its release—1.25% of the total amount between 6 h and 14 days. However, the Fb membrane binds TGF‐β1 not as strongly, which leads to more effective release of the compound—25% after 6 h and 28.98% of the total amount after 14 days. The factor TGF‐β1 is released in vitro from Fb–Ch membranes with different kinetics. The most efficient release of TGF‐β1 was observed in the case of the layered Fb–Ch (M4 L) membrane (after 14 days it reached a maximal value of 14.08% of the total amount). The release was lower with increasing Ch concentrations in the film, suggesting a high affinity of TGF‐β1 with the Fb–Ch component. The Fb–Ch membrane with incorporated TGF‐β1 may prove to be a very useful scaffold in the tissue regeneration process. This study demonstrates that Fb and MCCh gels could be used as carrier matrices for the controlled release of bioactive TGF‐β1. It was found that the degree of TGF‐β1 release from the membrane is influenced by the physiochemical and mechanical characteristics of the films and by its affinity to growth factor TGF‐β1. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Alzheimer disease is a neurodegenerative process of unknown mechanism taking place in a part of the brainhippocampus. Oxidative stress and the role of iron in it is one of the suggested mechanisms of cells death. In this study several methods were used to assess iron and iron binding compounds in human hippocampus tissues. Mössbauer spectroscopy was used for identification of the iron binding compound and determination of total iron concentration in 12 control and one Alzheimer disease sample of hippocampus. Mössbauer parameters obtained for all samples suggest that most of the iron is ferritin-like iron. The average concentration of iron determined by Mössbauer spectroscopy in control hippocampus was 45 ± 10 ng/mg wet tissue. The average concentration of iron in 10 Alzheimer disease samples determined by atomic absorption was 66 ± 13 ng/mg wet tissue. The concentration of H and L chains of ferritin in 20 control and 10 AD hippocampi was assessed with enzyme-linked immuno-absorbent assay. The concentration of H and L ferritin was higher in Alzheimer disease compared to control (19.36 ± 1.51 vs. 5.84 ± 0.55 ng/µg protein for H, and 1.39 ± 0.25 vs. 0.55 ± 0.10 for L). This 3-fold increase of the concentration of ferritin is accompanied by a small increase of the total iron concentration.
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