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22 results on '"Rund, Katharina M."'

13. Charakterisierung von oxidativem Stress, Lipidperoxidation und DNA‐Schädigung ausgelöst durch Häm‐Eisen in humanen Darmzellen

Author

Wittmann, Simon, primary, Wolf, Ann‐Cathrin, additional, Lukas, Sarah, additional, Seiwert, Nina, additional, Zinnert, Lilli, additional, Rund, Katharina M., additional, Frisch, Janina, additional, Prates‐Roma, Leticia, additional, Schebb, Nils H., additional, Hirayama, Tasuku, additional, and Fahrer, Jörg, additional

Published
2023
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16. Formation, Signaling and Occurrence of Specialized Pro-Resolving Lipid Mediators—What is the Evidence so far?

Author

Schebb, Nils Helge, primary, Kühn, Hartmut, additional, Kahnt, Astrid S., additional, Rund, Katharina M., additional, O’Donnell, Valerie B., additional, Flamand, Nicolas, additional, Peters-Golden, Marc, additional, Jakobsson, Per-Johan, additional, Weylandt, Karsten H., additional, Rohwer, Nadine, additional, Murphy, Robert C., additional, Geisslinger, Gerd, additional, FitzGerald, Garret A., additional, Hanson, Julien, additional, Dahlgren, Claes, additional, Alnouri, Mohamad Wessam, additional, Offermanns, Stefan, additional, and Steinhilber, Dieter, additional

Published
2022
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17. GC–MS analysis of oxysterols and their formation in cultivated liver cells (HepG2).

Author

Koch, Elisabeth, Bagci, Mustafa, Kuhn, Michael, Hartung, Nicole M., Mainka, Malwina, Rund, Katharina M., and Schebb, Nils Helge

Abstract

Oxysterols play a key role in many (patho)physiological processes and they are potential biomarkers for oxidative stress in several diseases. Here we developed a rapid gas chromatographic‐mass spectrometry‐based method for the separation and quantification of 11 biologically relevant oxysterols bearing hydroxy, epoxy, and dihydroxy groups. Efficient chromatographic separation (resolution ≥ 1.9) was achieved using a medium polarity 35%‐diphenyl/65%‐dimethyl polysiloxane stationary phase material (30 m × 0.25 mm inner diameter and 0.25 μm film thickness). Based on thorough analysis of the fragmentation during electron ionization we developed a strategy to deduce structural information of the oxysterols. Optimized sample preparation includes (i) extraction with a mixture of n‐hexane/iso‐propanol, (ii) removal of cholesterol by solid phase extraction with unmodified silica, and (iii) trimethylsilylation. The method was successfully applied on the analysis of brain samples, showing consistent results with previous studies and a good intra‐ and interday precision of ≤20%. Finally, we used the method for the investigation of oxysterol formation during oxidative stress in HepG2 cells. Incubation with tert‐butyl hydroperoxide led to a massive increase in free radical formed oxysterols (7‐keto‐chol > 7β‐OH‐chol >> 7α‐OH‐chol), while 24 h incubation with the glutathione peroxidase 4 inhibitor RSL3 showed no increase in oxidative stress based on the oxysterol pattern. Overall, the new method described here enables the robust analysis of a biologically meaningful pattern of oxysterols with high sensitivity and precision allowing us to gain new insights in the biological formation and role of oxysterols. [ABSTRACT FROM AUTHOR]

Published
2023
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18. Development of Analytical Methods to Investigate the Formation of Oxylipins during Oxidative Stress and Inflammation

Author

Rund, Katharina M. and Schebb, Nils Helge

Subjects
ddc:5:54:540, 500 Naturwissenschaften und Mathematik » 540 Chemie » 540 Chemie und zugeordnete Wissenschaften, Fakultät für Mathematik und Naturwissenschaften » Chemie » Dissertationen
Abstract

In the human body a vast number of oxidized polyunsaturated fatty acids (PUFA) is enzymatically and autoxidatively formed by conversion of n3- and n6-PUFA. Several of these oxylipins act as potent lipid mediators in the regulation of multiple physiological processes such as inflammation, endothelial and kidney function. However, the role of the overall oxylipin pattern is still only poorly understood. Thus, investigating the modulation of the oxylipin pattern in (patho)physiology, e.g. under oxidative stress or inflammation, or in response to dietary modulation, contributes to a better understanding of the functional role of oxylipins being both marker and mediator of the physiological status. In the first part of this thesis a comprehensive targeted LC-ESI(-)-MS/MS method is described for the sensitive and reliable quantification of a broad set of non-enzymatically and enzymatically formed oxylipins from all major formation branches derived from all biologically relevant PUFA precursors. In addition to the optimization of instrumental parameters, the influence of pre-analytical blood storage and transport conditions typically occurring in the clinical routine on the oxylipin pattern is characterized. In the second part of this thesis the established analytical method is applied to study the formation of oxylipins in the context of oxidative stress and inflammation. Focusing on the autoxidative formation of trans-epoxy-PUFA, the potential use of the trans/cis-epoxy-PUFA ratio as alternative oxidative stress marker is investigated. Therefore, this ratio is correlated with the formation of isoprostanes – common markers of oxidative stress – using (i) tert-butyl hydroperoxide as inducer of oxidative stress in three human carcinoma cell lines as well as in (ii) the in vivo model organism C. elegans and (iii) renal ischemia reperfusion injury in mice. Finally, the anti-inflammatory properties of n3-PUFA are investigated using a murine model of renal ischemia reperfusion injury causing both oxidative stress and inflammation. The modulation of the PUFA and oxylipin pattern is analyzed in combination with clinical and histological markers of kidney damage and inflammation.

Published
2020

20. Erythrocyte membrane polyunsaturated fatty acid profiles are associated with systemic inflammation and fish consumption in systemic lupus erythematosus: a cross-sectional study

Author

Vordenbäumen, Stefan, primary, Sokolowski, Alexander, additional, Kutzner, Laura, additional, Rund, Katharina M, additional, Düsing, Christina, additional, Chehab, Gamal, additional, Richter, Jutta G, additional, Brinks, Ralph, additional, Schneider, Matthias, additional, and Schebb, Nils H, additional

Published
2020
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