Proteins coagulation

Measurements of the coagulation proteins are generally the responsibility of the hematology laboratory and are usually confined to prothrombin time and activated partial thromboplastin time measurements, or some alternative measures of the performance of the intrinsic and extrinsic coagulation cascade pathways (Theus and Zbinden 1984). The coagulation proteins synthesized by the liver also can be used as markers of hepatotoxicity (Pritchard et al. 1987). 

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Factor VIII Coagulation proteins hemophilia A treatment 300 3 X 10- ... 

Vitamin K is an essential factor in the production of coagulation proteins within the liver. Elevated clotting times from decreased protein synthesis are indistinguishable from those produced by low vitamin K levels caused by malnutrition or poor intestinal absorption. Vitamin K (phytonadione) 10 mg subcutaneously daily for 3 days can help to establish whether the prolonged bleeding time results from loss of synthetic function in the liver or vitamin K deficiency. 

Hemophilia A and B are coagulation disorders that result from defects in the genes encoding for plasma coagulation proteins. Hemophilia A (classic hemophilia) is caused by the deficiency of factor VIII, and hemophilia B (Christmas disease) is caused by the deficiency of factor IX. The incidences of hemophilia A and B are estimated at 1 in 5000 and 1 in 30,000 male births, respectively. Both types of hemophilia are evenly distributed across all ethnic and racial groups.1... 

By far the most widely measured marker of hemostatic activation is D-dimer, which is a product formed by the action of plasmin on cross-linked fibrin (95). D-dimer levels in plasma are generally elevated in DIC. The consumption of platelets and coagulation proteins as a result of thrombin generation leads to the deposition of fibrin thrombi at multiple organ sites. This triggers fibrinolysis with an increase in the formation of fibrin degradation products, which can cause bleeding at multiple sites. Because DIC can have a variety of causes and may coexist with systemic fibrinolysis, such as in pulmonary embolism or deep vein thrombosis, the d-Dimer test is not specific for DIC (95). 

Citrated blood is diluted 1 10 with enzyme buffer solution, and preservative is added (H19). The buffer is prepared by dissolving 0.2 g of Clarase (Fisher Scientific Co., New York) in 100 ml citrate buffer (5 g potassium citrate monohydrate and 1 g citric acid monohydrate in 1000 ml distilled water, pH 5.6). The solution is incubated for 3 days at 37°. After incubation, it is autoclaved 15 minutes to stop enzymatic action and coagulate proteins. It is filtered, and 1.0, 1.5, and 2.0 ml of the supernatant is added to individual flasks and assayed. Control flasks are included to estimate pantothenic acid contamination of the enzyme. 

Liver or brain tissue is homogenized and lyophilized. The dried tissue is suspended in water (1 mg/ml), incubated 3 days at 37°, and autoclaved 10 minutes to coagulate protein. After removing die coagulum, the supernatant is assayed at 1, 1.5, and 2.0 ml, which represents 0.4, 0.6, and 0.8 mg/ml of basal medium (weight/volume) of dried tissue. 

They also suggested the lipids were released and became extractable primarily through enzymatic reactions after maceration of the leaves for extraction. Thus, they postulated that the time interval between maceration of the plant tissue and the application of heat to coagulate proteins was critical. They recommended heat inactivation of enzymes and precipitation of proteins as quickly as possible after maceration to minimize this interference. 

The appearance of anionic phospholipids, particularly phosphatidylserine, on the cell siuface activates prothrombinase complex culminating in the formation of thrombin (Bevers et al., 1982 Connor et al., 1989). The assay can be performed with pure coagulation proteins and specific chromogenic substtates to produce a very sensitive test to detect the appearance of phosphatidylserine on ceU siufaces. Nevertheless, it has been shown that changes in the disposition of phosphatidylethanolamine and sphingomyelin may interfere with the ability of phosphatidylserine-containing membranes to activate prothrombinase (Smeets et al., 1996). 

The blood plasma is an aqueous solution of electrolytes, nutrients, metabolites, proteins, vitamins, trace elements, and signaling substances. The fluid phase of coagulated blood is known as blood serum. It differs from the plasma in that it lacks fibrin and other coagulation proteins (see p. 290). 

This enzyme catalyzes the vitamin K-dependent post-translational carboxylation of specific glutamic acid residues in prothrombin and other blood coagulation proteins to form 4-glutamylcarboxylate side chains. 

Like coumarin derivatives, phenindione, a compound of the indandione class, acts by altering biosynthesis of coagulant proteins in the liver. It is used for preventing and treating thrombosis, thrombophlebitis, and thromboembolism. However, because of a number of side effects such as poly urea, polydipsia, tachycardia, and others, it is rarely used in practical medicine. Synonyms of this drug are pindone, bindan, gevuUn, indan, phenyhne, and rectadione. 

For some foods, incomplete extraction of color is obtained, probably due to the high binding affinity of dyes to the bulk of the food matrix, especially to proteins, lipids, and carbohydrates (156,161,162). This problem can be overcome by the use of selected solvents or enzymes to digest the food prior to extraction. Petroleum ether can be used to extract lipids (163). Acetone can be used to remove lipids and coagulate protein (164). Enzymes, such as amyloglucosidase (165,166), papain (167), lipase, pectinase, cellulase, and phospholipase, added to the sample and incubated under optimum pH and temperature conditions release synthetic colors bound to or associated with the food matrix. Furthermore, enzyme digestion can solubilize some foods, enabling analysis to be continued (156). 

Bentley, G., Gutsmann, V., Pasi, J. and Agnew, A. (2002) Characterisation of a schistosome anti-coagulant protein, SAP. Molecular and Cellular Biology of Helminth Parasites Conference, September 2002, Hydra, Greece. 

Antibodies directed against (32 -GPI further enrich the protein on the cell surface but these promote a p38 Map-kinase signalling cascade which results in increased expression of tissue factor (TF) and reduced expression of thrombomodulin on the surface of cells. TF is a major initiator of coagulation and increased levels of TF expression have been measured on endothelial cells treated with anti-phospholipid antibodies and on monocytes both ex vivo and in vivo (Yasuda et al., 2005 Lopez-lira et al., 2005, Lopez-Pedrera et al., 2006). Thrombomodulin is a potent anti-coagulant protein which limits activation of thrombin, so the net result of circulating anti-phospholipid antibodies is to usurp the anti-coagulative, protective mechanism and initiate a pro-coagulation cascade. 

Plasma contains protease inhibitors that rapidly inactivate the coagulation proteins as they escape from the site of vessel injury. The most important proteins of this system are -anti protease, 2-macroglobulin, -antiplasmin, and antithrombin. If this system is overwhelmed, generalized intravascular clotting may occur. This process is called disseminated intravascular coagulation (DIC) and may follow massive tissue injury, cell lysis in malignant neoplastic disease, obstetric emergencies such as abruptio placentae, or bacterial sepsis. 

Gelder, W.M.J. and van Vonk, C.R. (1980) Amino acid composition of coagulable protein from tubers of 34 potato varieties and its relationship with protein content. Potato Research 23,427-434. 

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