1. Clinic for Cardiovascular Disease, Clinical Center Nis, Nis, Serbia;
2. Institute for Cardiovascular Prevention and Rehabilitation Niska Banja, Nis, Serbia;
3. Clinic for Cardiovascular Surgery, Clinical Center Nis, Nis, Serbia;
4. Clinic for Endocrine Surgery and Breast Surgery, Clinical Center Nis, Nis, Serbia;
5. Clinic for Anesthesiology and Intensive Care, Clinical Center Nis, Nis, Serbia;
6. Departmant of Chemistry, Faculty of Medicine, University of Nis, Nis, Serbia