1. Department of Analytical Biochemistry, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
2. Department of Otorhinolaryngology, Head and Neck Surgery, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
3. Department of Pediatrics, University Medical Center Groningen (UMCG), University of Groningen, 9713 GZ Groningen, The Netherlands