title: Correspondence.
authors.affiliation: Department of Human and Animal Physiology, Wageningen Agricultural University, The Netherlands; Department of Surgery, Utrecht University Hospital, P.O. Box 85500, 3508 GA Utrecht, The Netherlands.
authors.forename: M J
authors.initials: MJ
authors.lastname: Verbeek
authors.forename: A
authors.initials: A
authors.lastname: van der Heijden
authors.forename: V V
authors.initials: VV
authors.lastname: Schreurs
authors.forename: L M
authors.initials: LM
authors.lastname: Akkermans
authors.forename: A
authors.initials: A
authors.lastname: Vos