The Altitude Inflammatory Bowel Disease Study

hypobaric chamber: ascent within 10 minutes, 3 hour exposure to hypoxic conditions simulating an altitude of 4,000 m.a.s.l., afterwards controlled descent under continuous pulsoximetric control

To retrieve biopsies from the colon during the course of the study 3 sigmoidoscopies were performed. The first sigmoidoscopy was performed 1 day before the stay in the hypobaric chamber. The second sigmoidoscopy was performed directly after the hypobaric chamber and the third sigmoidoscopy was performed 1 week after the hypobaric chamber. During each sigmoidoscopy 6 biopsies were taken with standard size forceps (2.4 mm). One biopsy was analysed by real-time quantitative polymerase chain reaction (PCR), one biopsy was analysed by Western blotting and another biopsy was analysed for gene gene-expression by in situ hybridisation. Two biopsies were analysed by immunohistochemistry (IHC) and one biopsy was stained with hematoxylin and eosin (H\&E).