1. At time of writing: General Hospital Trbovlje, Rudarska cesta 9, 1420 Trbovlje, Slovenia
2. At time of publication: Division of Surgery, Department of Abdominal Surgery, University Medical Centre Ljubljana, Zaloška c. 2, 1000 Ljubljana, Slovenia
3. Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
4. Animal Science Department, Biotechnical Faculty, University of Ljubljana, 1230 Domžale, Slovenia