Fibrin structure

Fibrinolytics. Figure 2 Various fibrin structures for plasmin. Fibrinogen (Fg) is converted to fibrin (F) by thrombin (T), and thrombin can also convert factor XIII (XIII) to activated factor XIII (Xllla). The latter produces crosslinks between fibrins (FxxF) and also may crosslink fibrin with a2-plasmin inhibitor (FxxFxxPI). The efficiency of digestion of these plasmin substrates by plasmin, resulting in the soluble fibrin degradation products (FDP), is different. The amount of FDP formed in time is expressed in arbitrary units. 

Summarizing the fibrinolytic therapy, it should be emphasized that efficient treatment needs urgent application of plasminogen activator (within a few hours) to prevent the formation of crosslinks in the fibrin structure (Fig. 2) and to find the localization of thrombus to emerge plasmin on the surface of fibrin to prevent rapid inactivation of the enzyme by the inhibitor system of fibrinolysis (Fig. 3). 

Freyssinet, J. M., Torbet.J., Hudry-Clergeon, G., and Maret, G. (1983). Fibrinogen and fibrin structure and fibrin formation measured by using magnetic orientation. Proc. Natl. Acad. Sci. USA 80, 1616-1620. 

R. A. S. (2003). Functional analysis of the fibrinogen AaThr312Ala polymorphism Effects on fibrin structure and function. Circulation 107, 2326-2330. 

Ariens RAS, Philippou H, Nagaswami C, etal, The FactorXIII V34L polymorphism accelerates thrombin activation of Factor XIII and affects crosslinked fibrin structure, Blood 2000 96 988-995. 

When the body requires blood to clot, as in the case of a cut or wound, enzymes are involved. Thrombin gathers in the area of the cut or wound and catalyses the soluble protein in the blood to form the insoluble fibrin structure, thus helping clotting and wound repair. The thrombin speeds up the rate of the reactions involved in the formation of insoluble fibrin from soluble protein. This is a simple example,... 

Thin fibrin fibers are more resistant to lysis and can result from a variety of factors and increase the risk of thrombosis. Whether abnormal fibrin structure and an increased thrombotic tendency play a role in patients who develop fenfluramine-associated pulmonary hjrpertension and valvular heart disease is a question that deserves further investigation. 

Carr ME Jr, Carr SL, Martin EJ, Johnson BA. Rapid clot formation and abnormal fibrin structure in a symptomatic patient taking fenfluramine - a case report. Angiology 2001 52(5) 361-6. 

Oenick, M.D.B. 2004. Studies on fibrin polymerization and fibrin structure - a retrospective. Biophys. Chem. 112 187-192. 

Laurens, N., Koolwijk, P., DeMaat, M.P., 2006. Fibrin structure and wound heaUng. J. Thromb. Haemost. 4, 932—939. 

Whereas in gelatin gels the network structure appears to involve associations of specific loci spaced far apart on the rodlike parent molecule and in denatured proteins the associations appear to be nonspecific, occurring anywhere along the polypeptide cluun in the fibrin structure both types of associations seem to be involved. The specific linkages differ from those of gelatin in that they are irreverdble and are probably primary chemical bonds. 

Spraggon, G., et al. Crystal structures of fragment D from human fibrinogen and its crosslinked counterpart from fibrin. Nature 389 455-462, 1997. 

Piechocka IK, Bacabac RG, Potters M et al (2010) Structural hierarchy governs fibrin gel mechanics. Biophys J 98 2281-2289... 

Figure 48-3. Schematic representation of fibronectin. Seven functional domains of fibronectin are represented two different types of domain for heparin, cell-binding, and fibrin are shown. The domains are composed of various combinations of three structural motifs (I, II, and III), not depicted in the figure. Also not shown is the fact that fibronectin is a dimer joined by disulfide bridges near the carboxyl terminals of the monomers. The approximate location of the RGD sequence of fibronectin, which interacts with a variety of fibronectin integrin receptors on cell surfaces, is indicated by the arrow. (Redrawn after Yamada KM Adhesive recognition sequences.

I Fibrinogen Both Forms structural basis of clot after its conversion to fibrin... 

An old hypothesis is based on the observations of Dahlen et al. (D3), who demonstrated that above a certain concentration in plasma, Lp(a) could bind to glycosaminoglycans in the arterial wall (B12). Colocalization of Lp(a) and fibrin on the arterial wall can lead to oxidative changes in the lipid moiety of Lp(a) and induce the formation of oxidatively modified cholesterol esters, which in turn can influence the interaction of Lp(a) and its receptors on macrophages. This process is promoted by the presence of calcium ions. Cushing (C14), Loscalzo (L22), and Rath (R3) reported a colocalization of undegraded Lp(a) and apo-Bl00 in the extracellular space of the arterial wall. In contrast to LDL, Lp(a) is a substrate for tissue transglutaminase and Factor XUIa and can be altered to products that readily interact with cell surface structures (B21). 

Structural Aspects of the Fibrinogen to Fibrin Conversion R. F. Doolittle... 

Blood and lymph These are the liquid tissues. It is, perhaps, surprising that they are classified as connective tissues, but their structure is the same as that of other connective tissues, except that the ground substance is fluid and the fibres are represented by the proteins such as fibrinogen and the strands of fibrin, which form when blood clots. The cells are the red and white cells (erythrocytes and leucocytes). 

Physiologically, the maintenance of blood circulating freely in the vascular system reflects a meticulous balance between coagulation and fibrinolysis. After microvascular injury subendothelial structures are exposed to which platelets adhere. This is followed by their aggregation and activation of the coagulation cascade with the ultimate conversion of fibrinogen to fibrin. 

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