|
Year |
2001 |
|---|---|
|
Question Number |
41. |
|
Category |
Select |
Question
The beneficial effects of aspirin in preventing thromboembolic disease are the result of
1. Reversible inhibition of cyclooxygenase
2. Activation of the fibrinolytic system
3. Binding of Antithrombin
4. Inhibition of Thromboxane A-2 synthesis
5. Replacement of normal clotting factors with decarboxylated factors
Figures
Answer (click for answer)
Answer: 4
Explanation: This question is merely the first sentence of the textbook written in the form of a question. Aspirin has a direct effect on Thromboxane A-2 formation by irreversibly inhibiting COX in platelets and megakaryocytes. Thromboxane A-2 is a powerful inducer of platelet aggregation.
Heparin is responsible for the binding of Antithrombin-III and activating the proteases of thrombin and factor Xa by a 1,000 fold.
Warfarin’s mechanism of action is the replacement of normal clotting factors with decarboxylated factors.
NSAIDs to varying degrees will have reversible inhibition of COX enzymes.
Reference: Buckwalter JA, Einhorn TA, Simon SR (eds): Orthopaedic Basic Science: Biology and Biomechanics of the Musculoskeletal System, ed 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000, pp 218-237.