Juhani Sand1, Isto Nordback2. 1. Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital, FIN-33521 Tampere, Finland. Electronic address: juhani.sand@pshp.fi. 2. Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital, FIN-33521 Tampere, Finland.