Introduction: Coronary Flow Reserve (CFR) is a clinically useful, non-invasive diagnostic method for assessing the functional ability of coronary arteries and it is important for their long-term follow-up in patients. However, CFR has not always been sufficiently investigated in previous studies. Objective: To examine the prognostic significance of CFR in the risk stratification of patients with chronic total occlusion of the right coronary artery (RCA) and the intermediary stenosis of the left coronary artery (LAD). Material and Methods: Number of 71 patients, mean age 64 ± 7 years, (84%) patients male, having LAD stenosis, diameter 50-70%, and CTO of RCA, were referred for noninvasive estimation of functional significance of LAD stenosis. Transthoracic Doppler echocardiography was used to obtain coronary flow velocities in the distal segment of LAD. Patients were followed for the mean period of 18.3 ± 7.1 months for the occurrence of composite end point including cardiovascular death, myocardial infarction, bypass surgery and PCI. Results: During the follow-up period, there were a total of 23 adverse events (4 deaths, 2 myocardial infarction, 7 bypass surgeries and 10 PCI). Patients with CFR < 2 had significantly more adverse events (n = 9; 56.3% vs. n = 14; 25.5%; p = 0.021), they were significantly older (68 ± 9 vs. 62 ± 6; p = 0.011), with a higher incidence of a positive family history (14; 87.5% vs. 26; 47.3%; p = 0.039), as well as a significantly higher frequency of three-dose coronary disease (14; 87.5% vs. 30; 54.5%; p = 0.017). Using Kaplan-Meier estimator, we obtained that patients with CFR < 2 have a significantly shorter average period without unwanted event (15.4 ± 2.8 months vs 23.5 ± 1.1 months, Log Rank 7.407; p = 0.008). Conclusion: CFR plays an important role in stratifying the risk of patients with CTO of RCA and the intermediary stenosis of LAD.

SažetakUvod: Metionin je sumporsta esencijalna aminokiselina koja, prema brojnim studijama, ima ulogu da smanji zapaljenje izazvano promenama u debelom crevu i inhibira važne puteve u razvoju brojnih gastrointestinalnih poremećaja. Suphronično opterećenje ovom aminokiselinom, međutim, dovodi do oksidativnog stresa koji je potencijalni uzročnik oboljenja brojnih organa, između ostalog i digestivnog trakta. N-acetil-Lcistein je prirodni antioksidans koji utiče na neke od važnih signalnih puteva, a poseduje i potencijalnu terapijsku ulogu u lečenju promena na kolonu. Cilj: Ispitati uticaj N-acetil-L-cisteina na histološke parametre kolona pacova nakon suphroničnog opterećenja metioninom. Materijal i metode: Eksperimenti su izvedeni na pacovima Vistar albino (Wistar albino) muškog pola, telesne mase 160 g i starosti 15-20 dana. U eksperimentu su korišćene 24 ži-votinje podeljene u 3 grupe, sa po osam životinja u svakoj grupi. Prvoj, kontrolnoj grupi (K) aplikovan je i.p. natrijumhlorid (NaCl), drugoj metionin (M grupa), a trećoj metionin + N-acetil-L-cistein (N grupa). Pacovi su nakon 21. dana lečenja žrtvovani i dobijeni su uzorci tkiva kolona. U sve tri navedene grupe analizirane su histološke promene u kolonu. Rezultati: Opterećenje metioninom dovodi do statistički veoma (p < 0,01) značajnog uvećanja dubine kripti u kolonu pacova, debljine lamine muskularis mukoze, debljine tunike mukoze, kao i gustine ćelija lamine proprije tunike mukoze u poređenju sa kontrolnom grupom, dok primena N-acetil-Lcisteina pokazuje veoma (p < 0,01) značajno smanjenje ovih histoloških parametara u odnosu na M grupu. Zaključak: N-acetil-L-cistein ima značajno protektivno dejstvo na promene u kolonu pacova izazvane opterećenjem metioninom. Ključne reči: N-acetil-L-cistein, metionin, kolon, pacov Abstract Introduction: Methionine is an essential sulfuric amino acid, which, according to numerous studies, has a role in the reduction of inflammation, caused by changes in colon, and inhibits important pathways in the development of numerous gastrointestinal disorders. However, subchronic methionine loading leads to oxidative stress, which is a potential cause of disease of numerous organs, digestive tract being one of them. N-acetyl-L-cysteine is a natural antioxidant, which affects some of the important signaling pathways and has a potential therapeutic role in treatment of colon disorders. Aim: To examine the influence of N-acetyl-L-cysteine on histological parameters of rat colon, after subchronic methionine load. Material and methods: Experiments were conducted on 15-20 days old male (Wistar albino) rats, weighing 160 g. There were used 24 animals in the experiment, divided into 3 groups, with eight animals per group. First, control group (K), received NaCl, second group received methionine (M group), while third group received methionine + N-acetyl-L-cysteine (N group). The rats were sacrificed after 21 day and tissue samples of colon were obtained. In all of the three groups, changes of histological parameters of rat colon were analyze...