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Hepner M.,Laboratorio Of Hemostasia Y Trombosis | Karlaftis V.,Murdoch Childrens Research Institute
Methods in Molecular Biology | Year: 2013

Protein C (PC) is a 62-kDa vitamin K-dependent plasma zymogen which, after activation to serine protease, plays an important role in the physiologic regulation of blood coagulation. Given that PC is one of the major naturally occurring inhibitors of coagulation, acquired or hereditary deficiencies of this protein result in excessive thrombin generation. As a vast array of mutations are responsible for hereditary PC deficiencies, screening for their presence by DNA testing would require sequencing each entire gene involving numerous exons. Moreover, the knowledge of the gene mutation does not offer any benefit in the treatment of thrombophilic families, so the routine molecular characterization is not indicative. These defects are detected by functional or immunological assays. Measurement of PC activity is essential to identify subjects with both type I and type II PC defects. There is no need to routinely perform PC immunological assays. However, they are useful in order to distinguish type I from type II PC hereditary deficiency. © 2013 Springer Science+Business Media New York.


Hepner M.,Laboratorio Of Hemostasia Y Trombosis | Karlaftis V.,Murdoch Childrens Research Institute
Methods in Molecular Biology | Year: 2013

Protein C (PS) is a vitamin K-dependent plasma glycoprotein. Around 60-70% of PS in plasma is noncovalently bound to C4-binding protein (C4BP). Free PS functions as a cofactor that enhances the activity of activated protein C (APC) in the proteolytic degradation of activated factors V and VIII. PS also has a more recently described APC-independent ability to directly inhibit prothrombinase and tenase by direct binding of activated factors V, VIII, and X. Given that PS is one of the major naturally occurring inhibitors of coagulation, acquired or hereditary deficiencies of this protein result in excessive thrombin generation. As a vast array of mutations are responsible for hereditary PS deficiencies, screening for their presence by DNA testing would require sequencing each entire gene involving numerous exons. Moreover, the knowledge of the gene mutation does not offer any benefit in the treatment of thrombophilic families, so the routine molecular characterization is not indicative. These defects are detected by functional or immunological assays for free and total PS forms. Given that functional PS assays may detect some forms of PS deficiency that free PS immunoassays may miss, it is recommended to include them for initial testing along with immunoassays for free PS, although they should be used with caution. Functional PS assays are subject to multiple interference. For example in the presence of lupus anticoagulant (LA), only free PS immunoassays are recommended for initial testing. PS antigen assays are more popular with most laboratories. © 2013 Springer Science+Business Media New York.


Hepner M.,Laboratorio Of Hemostasia Y Trombosis | Karlaftis V.,Murdoch Childrens Research Institute
Methods in Molecular Biology | Year: 2013

Antithrombin (AT) is a heparin cofactor and a member of the serine protease inhibitor family (serpin). The mature AT molecule is composed of 432 amino acids and it is produced mainly in the liver. Initially, several different AT activities in plasma were reported, leading to the classification of antithrombin in a range from I to IV. It was subsequently shown that these various antithrombin activities were the function of one molecule, antithrombin III, whose name was reduced to antithrombin at the meeting of the International Society in Thrombosis and Haemostasis in 1993. AT is an important protease inhibitor of thrombin and factor Xa. However, AT is also able to inhibit factors IXa, XIa, XIIab, kallikrein, and plasmin. Given that AT is one of the major naturally occurring inhibitors of coagulation, acquired or hereditary deficiencies of this protein result in excessive thrombin generation. As a vast array of mutations are responsible for hereditary AT deficiencies, screening for their presence by DNA testing would require sequencing each entire gene involving numerous exons. Moreover, the knowledge of the gene mutation does not offer any benefit in the treatment of affected families, so the routine molecular characterization is not indicative. These defects are detected by functional or immunological assays. AT amidolytic assays are recommended for initial testing for AT deficiency. There is no need to routinely perform AT immunological assays. However, they are useful in order to distinguish type I from type II hereditary AT deficiency. © 2013 Springer Science+Business Media New York.


Frontroth J.P.,Laboratorio Of Hemostasia Y Trombosis
Methods in Molecular Biology | Year: 2013

Laboratory testing of platelet function is essential for the diagnosis of several congenital and acquired platelet disorders. Moreover, it is increasingly being utilized to monitor the efficacy of antiplatelet therapy. Light transmission platelet aggregation is the most useful in vitro test of platelet function currently available, and it is still the gold standard to detect platelet disorders and to initiate a more precise characterization. © 2013 Springer Science+Business Media New York.


Camicia G.,Laboratorio Of Hemostasia Y Trombosis | Pozner R.,CONICET | De Larranaga G.,Laboratorio Of Hemostasia Y Trombosis
Shock | Year: 2014

Sepsis is the leading cause of death in critically ill patients in intensive care units. Early recognition of sepsis and proper therapy are essential to reduce patient mortality. Moreover, treatment options for this deleterious inflammatory response to infection are limited. Neutrophils play an essential role in the innate immune response, providing the first line of host defense. It has recently been shown that these cells can trap and kill microorganisms by releasing neutrophil extracellular traps (NETs) composed of chromatin and antimicrobial proteins. Although the beneficial role of NETs during infections has been demonstrated, there is increasing evidence that NETs and their components contribute to the pathogenesis of several diseases, including sepsis. The aim of this review was to summarize the current evidence implicating NETs, as well as their components, in the development of sepsis and to discuss their potential use as novel therapeutic targets and as prognostic markers in septic patients. Copyright © 2014 by the Shock Society.

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