1. Institute of Physiology, University Würzburg, 97070 Würzburg, Germany
2. Institute of Experimental Biomedicine, University Hospital Würzburg, 97080 Würzburg, Germany
3. Institute of Pathology, University Hospital Essen, 45147 Essen, Germany
4. Institute of Physiology, University of Regensburg, 93053 Regensburg, Germany