Platelet activation and aggregation

Administration of clopidogrel is recommended for all patients with STE ACS (Table 5—2).3 Clopidogrel blocks adenosine diphosphate receptors on platelets, preventing the expression of glycoprotein Ilb/IIIa receptors and thus platelet activation and aggregation. 

Human platelets Platelet activation and aggregation by inducing Ca2+ influx [112]... 

Fig. 9.1. A dysfunctional or injured endothelium is at the basis for initiation of and progression to atherosclerosis. Several mechanisms, such as adhesion molecules or liberation of von Willebrand factor (vWf, upper panel), determine a series of phenomena, including platelet activation and aggregation. This participation of platelets involves the implication of molecules like glycoprotein Ilb/IIIa, fibrinogen, and von Willebrand factor. The endothelium also acts as a source of signals that regulate local functions, including VSMCs (lower panel). A list of the most relevant messengers produced by a functional and a dysfunctonal endothelium is presented in the lower panel...

Detwiler and co-workers were the first to demonstrate a role for csPDI in platelet physiology (Chen et al, 1995 Essex et al, 1995). Essex and co-workers (1999, 2001) and Hogg and co-workers (Burgess et al., 2000) showed that the inactivation of csPDI with anti-PDI antibodies and thiol alkylating agents inhibited platelet activation and aggregation. Recent studies have identified two distinct activities for csPDI. 

Role of platelet activation and aggregation in cardiovascular diseases. (See p. 140.)... 

Clot formation requires platelet activation and aggregation, followed by formation of thrombin. This serum protease catalyzes the production of fibrin which, when cross-linked, stabilizes the clot. 

Chemical mediators influencing platelet activation and aggregation (relative size of platelets and endothelial cells are not to scale). 

PAPKOFF J, Chen R-H, BLENIS J, FORSMAN J. p42 mitogen-activated protein kinase and p90 ribosomal S6 kinase are sriecdvely phosphorylated and activated during thrombin-induced platelet activation and aggregation. Mol Cdl Biol 14 463-472,1994. 

Increased platelet activation and aggregation (e.g., gene polymorphisms of platelet glycoproteins Ilb/IIIa, la/IIa, and Ib/IX)... 

Injury Bleeding Stroma exposed to blood - VWF - Platelet activation and aggregation (TXA2, Ca2 and gla domain proteins)... 

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