Margarita Kessler

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Natural phosphatidylcholines, phosphatidylethanolamines and sphingomyelins have been investigated by field desorption and fast atom bombardment mass spectrometry. It is demonstrated that using these soft mass spectrometric ionization techniques, accurate, fast, and sensitive fatty acid profiling of phospholipids can be performed. With respect to the(More)
The absorption and fluorescence spectra of 3-aminobenzo-1,2,4-triazine di-N-oxide (tirapazamine) have been recorded and exhibit a dependence on solvent that correlates with the Dimroth ET30 parameter. Time-dependent density functional theory calculations reveal that the transition of tirapazamine in the visible region is pi-->pi* in nature. The fluorescence(More)
Cytotoxicity and genotoxicity of nitrogen dioxide (NO(2)) as part of urban exhaust pollution are widely discussed as potential hazards to human health. This study focuses on toxic effects of NO(2) in realistic environmental concentrations with respect to the current limit values in a human target tissue of volatile xenobiotics, the epithelium of the upper(More)
Current pollution limits indicating potential harm to human health caused by nitrogen dioxide have prompted a variety of studies on the cytotoxicity and genotoxicity of nitrogen dioxide (NO₂) in vitro. The present study focuses on toxic effects of NO₂ at the WHO defined 1-h limit value of 200 μg NO₂/m(3) air, equivalent to 0.1 ppm NO₂. Nasal epithelial(More)
The main classes of human plasma lipids, free fatty acids, cholesterol, cholesterol esters, triglycerides and phosphatidylcholines were identified and quantified from samples of human plasma by field desorption mass spectrometry. A crude lipid extract was prepared from 50 microliters of human plasma and a 1-5% aliquot thereof was subjected directly to field(More)
Stable, non-agglomerated TiO2 nanoparticle (NP) dispersions are a crucial requirement for an accurate NP dosing in in vitro and in vivo experiments. In this study self-synthesised TiO2 NPs were stabilised in three different cell culture media (DMEM, RPMI, BEGM) with the help of stabilising agents. Cell culture tested stabilisers (bovine serum albumin, fetal(More)
Levels of free and total cholesterol were quantified in control sera and human urine using [2H7]cholesterol or [13C2]cholesterol as internal standard and field desorption mass spectrometry for the quantification. These analyses are performed using a crude chloroform extract without chromatographic separation of the constituents. Due to the extremely soft(More)
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