| The organic nitrates have been used for more than a century in the management of angina pectoris and it has always been one of the most efficient and important drugs. But for a long time people only knew the vascular relaxing function of it. In recent 10 years, with the development research of endothelium - derived relaxing factor (EDRF) , the antiplatelet function of organic nitrates has been test and verified. P - selectin is a membrane protein stored both in the a- granules of platelets and in the Weibel - Palade bodies of endotheli-al cells, and is rapidly involved in mediating rolling when platelet is activated. On the other hand, the selectins belong to an indentified family of cell surface glycoproteins that have important roles as adhesion moleculers that influence the properties of leukocytes at the initiation of the inflammatory process. This study will observe the effects by isosobide dinitrate (ISDN ) on the expression of P - selectin and plasma level of TXB2 and 6 - keto - PGF1a using flow cytometry technique and ELISA. We also want to observe wether they have the dose- effect dependent relationship.Materials1. Sample ;(1)Study group: 61 patients(41 men and 20 women, aged from 44 to 76 years old, mean [64 ±12] years) with unstable angina who were admitted to the first affiliated hospital of china medical university between February 2001 and September 2001, were the subjects of this study. There was no history of aspirin therapy in the 10 days before the study. None of the patients was taking any nitrate in 48 hour before the study. None had hepatic disease, diabetes and bronchial asthma.(2) Control group; 20 healthy persons(13 men and 7 women, aged from 42 to 55 years old, mean [50 ± 6 ] yeas) were taken as control.2. Reagents and apparatuses;Isosorbide dinitrate, TXB2 kits, 6 - keto - PGFla kits, FITC - P - selectin antibodies, Elx 800 EIA photometer, 05 PR - 22 Refrigerated Centrifuge, FACSCAN Flow cytometer.Methods1. In vivo study;The first 45 patients with angina pectors were random single -blinded to receive infusion of ISDN at the rate of 2mg . h-1, 4mg . h-1 and 8mg . h-1. Blood sample (4ml) was performed 10 minutes before and 2,8 hour after the infusion was begun.2. In vitro study;16 unstable angina patients were randomly selected. A sample of whole venous blood (10 ml) was drawn at early morning before breakfast to obtain platelet rich plasma. Eight 200ul aliquots prewarmed to 37℃ were divided into 2 equal groups. The plasma in 3 cuvettes of group A was incubated for 5 minutes at 37℃ with 1. 25 ug .ml-1,12. 5ug . ml-1 and 125ug . ml-1 of ISDN respectively and the remaining cuvette was incubated with the vehicle alone (PBS) as a control. Gu-vettes in group B similarly treated, except that incubation time was 2 hour.3. In healthy control:The anteubital vein was drawn at early morning before breakfast.4. Determination of P - selectin expression:Blood samples were drawn in plastic syringes that contained sodium citrate 3.8% was centrifuged at 800r for 5 minutes to obtain PRP. After the activation with ADP (FC, 2umol.l-1) , the samples were incubation with the FITC - conjugated specific antibodies of P - selectin for 20 minutes in the dark at 22^. After fixation with cellfix, the samples were measured in a flow cytometer within 6 hour. For each sample, 10000 platelets were collected. Data were analyzed with Cell - Quest software.5. Determination of TXB2 and 6 - keto - PGF1a:200ul aliquot of PRP was incubated with ADP (FC, 2umol. l-1) for 5 minutes in 22℃ , and centrifuged at 3000r for 10 minutes. The supernate was then stored frozen at - 70℃ until assay with ELISA.6. Statistical analysis:Quantitative date were expressed in mean ± SEM, paired T test was used and A value of P < 0. 05 was considered to be statisticallysignificant.Results1. The expression of platelet P - selectin and plasma level of TXB2 in unstable angina patients were significantly higher than those in healthy cont...
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