1. Institute of Clinical and Preventive Medicine, University of Latvia, LV-1079 Riga, Latvia
2. Mass Spectrometry Group, Latvian Institute of Organic Synthesis, LV-1006 Riga, Latvia
3. Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, LV-1006 Riga, Latvia
4. Riga East University Hospital, LV-1038 Riga, Latvia
5. Faculty of Medicine, University of Latvia, LV-1004 Riga, Latvia
6. Digestive Diseases Centre GASTRO, LV-1586 Riga, Latvia