[1] Inst J Paoli I Calmettes, Oncol Unit 1, F-13273 Marseille 9, France
[2] Inst J Paoli I Calmettes, Endoscop Unit, F-13273 Marseille, France
[3] Calif Pacific Med Ctr, Intervent Endoscopy Serv, San Francisco, CA USA
[4] Univ Frankfurt, Zentrum Inneren Med, Med Klin 2, D-6000 Frankfurt, Germany