The Publisher regrets that this article is an accidental duplication of an article that has already been published, DOI of original article: http://dx.doi.org/10.1053/j.gastro.2011.03.019.The duplicate article has therefore been withdrawn.
The Publisher regrets that this article is an accidental duplication of an article that has already been published, DOI of original article: http://dx.doi.org/10.1053/j.gastro.2009.03.025.The duplicate article has therefore been withdrawn.