Oxidative stress and platelet activation in subjects with moderate hyperhomocysteinaemia due to MTHFR 677 C→T polymorphism.

The methylenetetrahydrofolate reductase (MTHFR) 677 C→T polymorphism may be associated with elevated total homocysteine (tHcy) levels, an independent risk factor for cardiovascular disease. It was the study objective to evaluate in vivo lipid peroxidation and platelet activation in carriers of the MTHFR 677 C→T polymorphism and in non-carriers, in relation to tHcy and folate levels. A cross-sectional comparison of urinary 8-iso-prostaglandin (PG)F(2α) and 11-dehydro-thromboxane (TX)B(2) (markers of in vivo lipid peroxidation and platelet activation, respectively) was performed in 100 carriers and 100 non-carriers of the polymorphism.

Aspirin-insensitive thromboxane biosynthesis in essential thrombocythemia is explained by accelerated renewal of the drug target.

Essential thrombocythemia (ET) is characterized by enhanced platelet generation and thrombotic complications. Once-daily low-dose aspirin incompletely inhibits platelet thromboxane A(2) (TXA(2)) in the majority of ET patients. In the present study, we investigated the determinants of aspirin-insensitive platelet TXA(2) biosynthesis and whether it could be further suppressed by changing the aspirin dose, formulation, or dosing interval.

Deep venous thrombosis and previous myocardial infarction in mild factor XII deficiency: a risk factor for both venous and arterial thrombosis.

Factor XII deficiency is associated with increased risk for both arterial and venous thrombosis. We describe a case of DVT involving superficial femoral and popliteal vein occurred following total hip replacement and despite prophylaxis with low molecular weight heparin in a subject with previous acute myocardial infarction (AMI). Tests of haemostasis documented a slightly prolonged activated partial thromboplastin time (APTT) (45'') due to mild factor XII deficiency (clotting activity 32%).