[1] Univ Hosp Lozenetz, Dept Anesthesiol & Intens Care, 1 Kozyak Str, Sofia 1407, Bulgaria
[2] Sofia Univ, Med Fac, St Kliment Ohridski, Kozyak 1 Str, Sofia 1407, Bulgaria
[3] Med Univ Sofia, Med Fac, Dept Pharmacol & Toxicol, 1 Georgi Sofiiski Str, Sofia 1431, Bulgaria
[4] Med Univ Plovdiv, Dept Diagnost Imaging, Bul Vasil Aprilov 15A, Plovdiv 4000, Bulgaria
[5] Univ Hosp Lozenetz, Dept Gastroenterol, Sofia 1407, Bulgaria
[6] UMHAT Sv Georgi, Clin Endocrinol & Metab Disorders, Plovdiv 4000, Bulgaria
[7] Natl Specialized Hosp Act Treatment Hematol Dis, Lab Hematopathol & Immunol, Plovdivsko Pole Str, 6, Sofia 1756, Bulgaria
[8] Sofia Univ St Kliment Ohridski, Dept Genet, Fac Biol, 8 Dragan Tzankov Str, Sofia 1164, Bulgaria
[9] New Bulgarian Univ, Dept Informat, Montevideo 21 Str, Sofia 1618, Bulgaria
[10] Univ Hosp NI Pirogov, Pediat Clin, 21 Gen Eduard I Totleben Blvd, Sofia 1606, Bulgaria
[11] Med Univ Sofia, Fac Publ Hlth Prof Tsekomir Vodenicharov, Dept Healthcare, Bialo More 8 Str, Sofia 1527, Bulgaria
[12] Med Univ Plovdiv, Dept Gen & Clin Pathol, Bul Vasil Aprilov 15A, Plovdiv 4000, Bulgaria