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@#ObjectiveTo investigate the mechanism on endothelial dysfunction of spontaneous hypertensive rats (SHR).MethodsThe animals were divided into two groups: SHRs (n=8) and Wistar-Kyoto (WKY) rats (n=7) all aged 17 months. Blood pressure was measured by the tail-cuff method. NO3- concentration in serum was assayed by activated cadmium reduction method; endothelin (ET) and cGMP levels were assayed by RIA.ResultsCompared with WKY rats, blood NO3- concentration, ET level and vascular cGMP level of SHRs were all reduced significantly (P<0.01); vascular ET level was only uplifted slightly with no significant difference (P>0.05).ConclusionIt indicates that the vascular endothelial dysfunction in SHR is induced possibly by a diminished synthesis or release of NO, not by changes of ET level.
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To investigate the changes of activated platelet marker and its significance in older hypertensive patients, glycoprotein Ⅱb/Ⅲa(PAC 1)and P selectin(CD62P) were used as molecular markers for activated platelets,which were analyzed by flow cytometric 3 color immunofluorescence. The results showed that PAC 1 expression on platelet membrane surface in older hypertensive patients was higher than that in healthy individuals and was not related with mean blood pressure.However, the expression of CD62P on platelets membrane surface did not differ in the two groups.These results suggest that PAC 1 may be regarded as a sensitive and specific molecular marker for activated platelets. Platelet activation occurrs in older hypertensive patients, and is of great importance for the antiplatelet therapy in hypertensive patients.
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Endothelin (ET) is an endothelium-derived vasoconstrictive peptide. We have developed a sensitive and selective radioimmunoassay for porcine/human endothelin (ET-1). 126I-labled ET was perpared by lodogen method and was purified by HPLC. Its specific activity was about 64.75 TBq(1750Ci)/mmol. The assay has a detection limit of 0.17pg/tube and the assay range was 0.25-1000pg/tube. The procedure was developed for extraction of endothelin from human plasma using C18 Sep-pak extraction cartridges. Human plasma samples were extracted, assayed and the plasma ET values of 17 healthly volunteers was found to be 2.81 ?0.60pg/ml. Both patients with uraemia(n = 20) and acute myocardial infarction(n= 11) had significantly higher plasma values than normal subjects.