1. Institute for Analytical Sciences (ISAS), Dortmund;
2. Department of Analytical Chemistry, Ruhr-University-Bochum, Bochum;
3. Institute for Clinical Biochemistry and Pathobiochemistry and Central Laboratory, University Würzburg, Würzburg; and
4. Medizinisches Proteom-Center (MPC), Ruhr-University-Bochum, Bochum, Germany