1. Faculty of Medicine, Riga Stradins University, 16 Dzirciema Street, LV-1007 Riga, Latvia
2. Centre of Cardiac Surgery, Pauls Stradins Clinical University Hospital, 13 Pilsonu Street, LV-1002 Riga, Latvia
3. Joint Laboratory of Electron Microscopy, Riga Stradins University, 9 Kronvalda Boulevard, LV-1010 Riga, Latvia
4. Laboratory of Biomechanics, Riga Stradins University, 5a Ratsupites Street, LV-1067 Riga, Latvia
5. Institute of Microbiology and Virology, Riga Stradins University, 5 Ratsupites Street, LV-1067 Riga, Latvia