1. Institute of Clinical and Preventive Medicine, University of Latvia, LV-1586 Riga, Latvia
2. Faculty of Medicine, Riga Stradins University, LV-1007 Riga, Latvia
3. Riga East University Hospital, LV-1038 Riga, Latvia
4. Health Centre 4, LV-1012 Riga, Latvia
5. Department of Modelling and Simulation, Riga Technical University, LV-1048 Riga, Latvia
6. Liepaja Regional Hospital, LV-3414 Liepaja, Latvia
7. Department of Doctoral Studies, Riga Stradins University, LV-1007 Riga, Latvia
8. Digestive Diseases Centre GASTRO, LV-1079 Riga, Latvia
9. Faculty of Medicine, University of Latvia, LV-1586 Riga, Latvia
10. Institute for Breath Research, University of Innsbruck, 6020 Innsbruck, Austria
11. Institute of Chemistry, Jan Kochanowski University of Kielce, 25-369 Kielce, Poland