Posts Tagged ‘disseminated intravascular coagulation’

Impact-R and Disseminated Intravascular Coagulation

Thursday, January 12th, 2012

Impact-R, a cone and plate analyzer can detect defects in platelet adhesion and aggregation. It can be of use in research about DIC.

What is Disseminated Intravascular Coagulation?

DIC is pathological activation of coagulation mechanisms in response to a variety of substances seen in disease states. Activation of coagulation causes blood clots to form in the small blood vessels of most organs in the body. This has two effects: disruption of blood flow to the organs whose blood vessels have small blood clots resulting in malfunction of the organ; and consumption of blood clotting factors and platelets resulting in bleeding elsewhere in the body.

Normally, the human body is maintained in homeostasis, a balance of coagulation and fibrinolysis, with both processes counterchecking each other through feedback mechanisms. In DIC, these mechanisms are dysregulated. A critical component in the triggering mechanism is tissue factor or TF, also known as platelet tissue factor or Factor III. It is found in subendothelial tissue, platelets and leukocytes. TF is released in response to cytokines, tumor necrosis factor, and endotoxin.

DIC can be caused by many conditions. These include malignancies, obstetrics, trauma, infections, toxins and poisons. These conditions trigger the release of tissue factor and subsequently activate the extrinsic pathway of coagulation.

The role of Impact-R in Research

Since tissue factor can be found in platelets, addition of substances that release tissue factor to platelets will result in coagulation. Impact-R can be used to determine which substances can elicit release of tissue factor.

Impact-R as Adjunct Diagnostic Test for Congenital Protein C or S Deficiency

Saturday, January 7th, 2012

Impact-R, a test for platelet function, has potential use as adjunctive diagnostic test to identify protein C or S deficiency.

A blood clot.

What is protein C or S deficiency?

Protein C and S are proteins found in the plasma that participate in the coagulation cascade as regulators of thrombin formation by inhibition of Factor VIIIa and Factor Va. Protein C is activated by thrombin-thrombomodulin complex then combines with free Protein S, its cofactor, to inhibit Factor VIIIa and Factor Va.

Inherited protein C or S deficiency is rare and occurs independently of each other. Protein C or S abnormalities include decreased levels of either protein, inability to bind with each other, protein C/S complex that that cannot degrade factors VIIIa and Va, increased clearance of Protein S.

Deficiencies of either protein C or S results in non-inhibition of factors VIIIa and Va and continuous, unchecked formation of thrombin. This leads to hypercoagulability of patient’s blood, and may result in deep vein thrombosis, venous thromboembolism, purpura fulminans or disseminated intravascular coagulation.

What are the tests for protein C or S deficiency?

Laboratory tests include Functional Protein C, Functional Protein S, Protein C Antigen and Protein S Antigen. These are specific for the Protein deificiency.

Adjunctive tests include Bleeding time, Partial Thromboplastin time, Prothrombin time and Thrombin time.

What is the use of Impact-R in diagnosing protein C or S deficiency?

Impact-R can be of use in the diagnosis of protein C or S by determining the effect of adding free protein S and activated protein C in the platelet adhesion and aggregation of whole blood of patients with the suspected deficiency. This can be an alternative in cases where the Protein C or S assays are not available.

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