Interaction with coagulation

III. Decoding the Regulating Structural Feature of MSPs in Interactions with Coagulation (co)-factors 201... 

III. DECODING THE REGULATING STRUCTURAL FEATURE OF MSPS IN INTERACTIONS WITH COAGULATION (CO)-FACTORS... 

The nature of chemical coagulants are such that the macrofloc may possess certain charges for example lime (CaO), alum (A1203) and flocculating polyvalent cations cany positive charges, which interact with proteins. The interactions are simply illustrated in Figure 7.6. 

HK it can interact with surface-bound factor XII on an adjacent particle thereby disseminating the reaction [25, 28]. As a result the effective kallikrein/factor XII ratio is increased in the presence of HK [25], Finally, in plasma, HK can displace other adhesive glycoproteins such as fibrinogen from binding to the surface [29]. In this sense, HK, like factor XII and prekallikrein, is also a coagulation cofactor because it is required for the generation of kalUkrein (a factor XII activator) as well as the activation of factor XI. 

Given that thrombin is the central mediator of coagulation and amplifies its own production, it is a natural target for pharmacologic intervention. Direct thrombin inhibitors (DTIs) bind thrombin and prevent interactions with its substrates (Fig. 7-7). Several injectable DTIs are approved for use in the United States including lepirudin, bivalirudin, arga-troban, and desirudin. Several oral DTIs are currently in... 

Interaction with Other Cascade Systems. Interactions between the complement system, the kinin, and the coagulation and fibrinolytic systems have repeatedly been reported (S37, PI9). Activation of one system induces activation of the other systems. The reciprocal activation of the various cascade systems may have an important role in the pathogenesis of ARDS and MODS as complications of sepsis. Nevertheless, until now no convincing prophylactic or therapeutic effects of intervention in the complement cascade system on the severity of septic complications have been reported. 

As shown in Fig. 7.7d polymers can destabilize colloids even if they are of equal charge as the colloids. In polymer adsorption (cf. Fig. 4.16) chemical adsorption interaction may outweigh electrostatic repulsion. Coagulation is then achieved by bridging of the polymers attached to the particles. LaMer and coworkers have developed a chemical bridging theory which proposes that the extended segments attached to one of the particles can interact with vacant sites on another colloidal particle. 

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