Components of the hemostatic system

Primary and even tertiary structures are now known for many of the hemostatic system proteins. Gene structures have been identified for all of the known components of the hemostatic system. Databases listing mutations and their related hemorrhagic or thrombotic risks are growing rapidly. For many reactions, the molecular mechanisms responsible for the properties of the hemostatic... 

Estrogen therapy has been linked to changes in the concentrations of several components of the hemostatic system. However, there are no changes in components of the procoagulant, anticoagulant, or fibrinolytic system that can be clearly linked to an increase in risk of thromboembolic disease sometimes associated with estrogen therapy. 

Although the many components of the hemostatic system inevitably create a high level of complexity, the functional and structural similarities between and among the different molecules permit the simplification described above. Simplification can be obtained by representing many of the molecules as ellipses, the two-dimensional representations of the generally ellipsoid shapes of the molecules in solution (see Figure 36-9 below). However, the common motifs and similar proteinase domain structures can be presented even more simply in the form of bar diagrams, which are usually used in the descriptions of reactions that follow. 

A 30-year-old man with recurrent thrombosis is referred to you for diagnosis. The PT and APTT results determined on his freshly drawn plasma sample are 10.1 s (normal 10-12 s) and 18 s (normal 20-32 s). Which components of the hemostatic system would you initially suspect as being... 

First, it was determined whether or not aerogel samples would induce platelet activation upon contact. To investigate this, washed platelets were incubated with aerogel samples for up to 6 h. The expression of phosphatidylserine (PS) and P-selectin (CD-62P) was measured to determine how platelets responded to aerogel contact. Platelets are a critical component of the hemostatic system and play a salient role in clot formation. 

Documented effects An extract of this herb sharply iuCTeases blood pressure, due to its high noradrenaline content. Hemostatic action for internal hemorrhaging has been documented (Khalmatov 1964). In experiments with mice and rats, an ethanolic extract of the dried aboveground parts showed significant antiinflammatory and analgesic effects after intra-peritoneal and topical, but not oral, administration (Chan et al. 2000). Studies indicated that the consumption of the plant may help to reduce the occurrence of cancer and heart diseases. Catecholamines (noradrenaline and dopamine) contained in the plant are generally considered to be the effective component in the treatment of shock. Studies have also shown that noradrenaline is a modulator of the immune system and may have anti-cancer properties (Chen et al. 2003). 

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