1.   Furthermore, rectal biopsy specimens were obtained from each twin in whom sigmoidoscopy could be carried out.

2.   We did not look at the histological correlate of the inflammatory mediators as for ethical reasons we did not perform sigmoidoscopy and rectal biopsy.

3.   Initial rectal biopsy and subsequent ileal and colonic biopsies at colonoscopy before treatment all showed similar features.

4.   Rectal biopsy specimens were divided into tiny explants and orientated mucosal surface uppermost on a metal grid within an organ culture dish.