[1] FREE UNIV BERLIN,KLINIKUM BENJAMIN FRANKLIN,GASTROENTEROL ABT,D-12200 BERLIN,GERMANY
[2] FREE UNIV BERLIN,KLINIKUM BENJAMIN FRANKLIN,DEPT NUCL MED,D-12200 BERLIN,GERMANY
[3] FREE UNIV BERLIN,KLINIKUM BENJAMIN FRANKLIN,DEPT PATHOL,D-12200 BERLIN,GERMANY
[4] UNIV COPENHAGEN,RIGSHOSP,DEPT CLIN BIOCHEM,DK-2100 COPENHAGEN,DENMARK