Poster Sessions 68 PO19 Vascular endothelium extracellular domain of the human αIIb subunit, is a potent inhibitor of human platelet activation. We investigated the inhibitory effect of YMES- RADR and the synthetic peptide RPPLEED, which corresponds to residues 997-1003 of the intracellular domain of the human αIIb subunit, on rabbit platelet aggregation. Methods: YMESRADR and RPPLEED (as well as its palmitoylated form, Palm-RPPLEED), were synthesized by the Fmoc/tBut strategy. Platelet aggregation, induced by ADP, Arachidonic Acid (AA) and PAF, was studied in rabbit platelet rich plasma (PRP) and washed platelets. Results: YMESRADR significantly inhibits ADP-, AA- and PAF- induced rabbit platelet aggregation, in a dose-dependent manner. Palm- RPPLEED but not the RPPLEED, is capable to enter the platelet as it is shown by fluoresence microscopy and to significantly inhibit platelet aggregation in a dose-dependent manner. This inhibitory effect is greater in washed platelets rather than in PRP, since albumin significantly suspends the peptide’s inhibitory effect. Importantly, the combination of YMESRADR with Palm-RPPLEED exhibits an important synergistic inhibitory effect on platelet aggregation. Discussion: The peptide YMESRADR inhibits rabbit platelet aggrega- tion in a non RGDS-dependent mechanism. Furthermore, in combination with Palm-RPPLEED, it exhibits a potent synergistic inhibitory effect, independently on the platelet agonist. Such a combination of peptides could introduce a new generation of strong anti-platelet agents. PO19-208 THE IMPACT OF SERUM URIC ACID LEVEL ON CORONARY BLOOD FLOW A. Yildiz 1 , R. Yilmaz 1 , R. Demirbag 1 , M. Gur 1 , M. Bas 1 , O. Erel 2 . 1 Department of Cardiology, Harran University School of Medicine, Sanliurfa, Turkey; 2 Department of Clinical Biochemistry, Harran University School of Medicine, Sanliurfa, Turkey Background and aims: Slow coronary flow (SCF) has long been identified and endothelial dysfunction and atherosclerosis of epicardial coronary ar- teries and microvasculature were reported to be associated with SCF. Serum uric acid is an independent biochemical marker of atherosclerosis, oxidative stress and endothelial dysfunction. Consequently, we aimed to investigate the association between coronary blood flow and serum uric acid level and laboratory parameters in patients with SCF compared to control cases. Methods: Sixty-four patients with SCF and 369 control cases were studied after quantifying coronary blood flow according to TIMI frame count (TFC). Serum uric acid level was determined using commercially available assay kits. The association between TFC and serum uric acid level and other clinical and laboratory parameters were evaluated. Results: There were significant differences between SCF and control groups with respect to serum uric acid, urea levels, hemoglobin level, heart rate, cigarette smoking, and gender. The mean TFC was significantly correlated with serum uric acid, urea, creatinine and HDL cholesterol levels, hemoglobin level, platelet count, male gender, cigarette smoking, heart rate and systolic blood pressure. Serum uric acid level (χ2=22.86, ß=0.54, p<0.001), heart rate (χ2=7.42, ß=-0.034, p=0.032) and cigarette smoking (χ2=12.343, ß=0.969, p=0.025) were independent predictors of SCF, whereas serum uric acid level was the only independent predictor of the mean TFC (β=0.298, p<0.001). Conclusions: These findings have shown that serum uric acid level is significantly associated with coronary blood flow and elevated serum uric acid level might be an independent predictor of the presence of SCF. PO19-209 IN VITRO STUDY OF PHOTODYNAMIC EFFECTS ON HUMAN ENDOTHELIAL CELLS E. Andreeva 1 , O. Udartseva 1 , E. Tararak 1 , S. Kuzmin 2 , I. Vozovikov 3 . 1 Cardiocenter, Moscow, Russia; 2 FSUE NIOPIK, Moscow, Russia; 3 FSUE Krasnaya Zvezda, Moscow, Russia Objectives: Chloroaluminum sulfonated phthalocyanine (Photosens (PS) - NIOPIK, Russia) is a photosensitizer that is widely used in photodynamic therapy (PDT) of tumor deseases. Recently it was proposed to use PDT in treatment of cardiovascular pathology like restenosis and atherosclerosis. Endothelial cell (EC) is an important part of cellular community of vascular wall. This study was designed to characterize the effects of PDT on EC viability and to define the cell-death pathway for PS. Methods: Human umbilical vein EC were obtained and cultured as described elsewhere. 24 h before PDT 2-100ug/ml of PS was added to culture medium. Then cells washed carefully and illuminated with 675-nm light (0.5-20 J/cm 2 ). Cellular viability was measured with MTT test. Apoptosis/necrosis was assessed by use of annexin V-PI kit. Intracellular ROS was visualized with DCF-DA. Results: Either PS accumulation alone or laser illumination alone did not affect cells. Illumination of PS loaded cells with 675-nm light (0.5-20 J/cm 2 ) impaired cellular viability in dose-dependent maner. Apop- totic/necrotic cells ratio was also illimination dose-dependent. PDT was associated with interacellular ROS formation. Conclusions: In vitro EC model may be useful tool for screening of PDT effects on vascular wall. Funding: This research was supported in part by ISTC grant 2579 and RFBR grant 07-04-0150a PO19-210 ENDOTHELIAL DYSFUNCTION AND OXYGEN TRANSPORTING FUNCTION OF BLOOD IN PATIENTS WITH CORONARY HEART DISEASE L.V. Yankovskaya . Department of Cardiology, City Hospital No. 3, Grodno, Belarus The influence of nitric oxide on formation of oxygenbinding qualities blood can have a very important significance in pathogenesis of coronary heart disease (CHD). The aim of the study was to assess the endothelial function and to investigate the blood oxygen transport indices in patients with stable CHD. Methods: The study population were divided into three groups: group A – 30 patients with CHD I class, group B – 38 patients with CHD II class, group C – 13 patients with CHD III class. The forearm blood flow (FBF) was measured using strain-gauge plethysmography during reactive hyperemia. Plasma nitrite/nitrate level was determined using Griess method. The blood oxygen indices: blood pO2, pCO2, pH were measured using microgasoanalyzer. The hemoglobin-oxygen affinity (HOA) was determined according to the p50 index. Results: FBF during reactive hyperemia reduced in groups with dis- ease progress (group A – 12,83±1,08%, group C – 2,14±1,74%). The nitrite/nitrate level was minimal in group C (11,03±0,91 mmol/l, p<0,001). Value pO2 were lowed (p<0,001), value pCO2 were increased (p<0,05) in all groups to compare in control. Minimal value of pH (7,299±0,009 unit) was in group C. HOA reduces with the increasing of class CHD (p50 actual in group A – 27,4±0,5 mmHg; group C – 29,7±0,7 mmHg). A moderate positive correlation was found between the FBF and p50, the FBF and pH. Conclusions: Thus, the higher functional class of CHD, the more pro- nounced signs of endothelial dysfunction. This is closely pathogenetically connected with the evidence of hypoxia in organism, metabolic acidosis and decreasing of HOA. PO19-211 ASSOCIATION OF PLASMA HYALURONIDASE ACTIVITY WITH ATHEROSCLEROSIS IN PATIENTS WITH CORONARY ARTERY DISEASE B. Karadag 1 , M. Kucur 2 , F.K. Isman 3 , D. Duman 4 , M. Baskurt 1 , F. Aliyev 1 , B. Vatan 1 , H. Firinciogullari 1 , V.A. Vural 1 . 1 Istanbul University, Department of Cardiology, Cerrahpasa School of Medicine, Istanbul, Turkey; 2 Istanbul University, Fikret Biyal Research Laboratory, Cerrahpasa School of Medicine, Istanbul, Turkey; 3 Taksim Training and Research Hospital, Department of Clinical Biochemistry, Istanbul, Turkey; 4 Haydarpasa Training and Research Hospital, Department of Cardiology, Istanbul, Turkey Background and Objective: Recent information has highlightened the impact of HA metabolism alterations in vascular permeability through its actions on endothelial glycocalyx and the importance of HA-cell interactions in cell behavior of arterial endothelial and smooth muscle cells. Therefore hyaluronan is thought to involve in pathophysiology atherosclerosis. The aim of this study is to investigate the association of plasma hyaluronidase activity with atherosclerosis in non-diabetic patients with stable coronary artery disease. Methods: In the present study we used plasma hyaluronidase measure- ment as an indicator of hyaluronan metabolism and activity. A total of 200 subjects undergoing to coronary angiography were divided into four subgroups according to the number of diseased vessels and their serum hyaluronidase activity were measured. Results: Serum hyaluronidase activities were 3334±462.97 mU/L, 4159±548.63 mU/L, 5619±1329.04 mU/L and 2838±417.67 mU/L for 77th Congress of the European Atherosclerosis Society, April 26–29, 2008, Istanbul, Turkey