Rogier M. Bertina

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Activated protein C (APC) is a serine protease with potent anticoagulant properties, which is formed in blood on the endothelium from an inactive precursor. During normal haemostasis, APC limits clot formation by proteolytic inactivation of factors Va and VIIIa (ref. 2). To do this efficiently the enzyme needs a nonenzymatic cofactor, protein S (ref. 3).(More)
We investigated whether the occurrence of venous thrombosis in young women who use oral contraceptives might be explained by the factor V Leiden mutation, which leads to resistance to activated protein C and enhances susceptibility to thrombosis. We compared 155 consecutive premenopausal women, aged 15 to 49, who had developed deep venous thrombosis in the(More)
Thrombin activatable fibrinolysis inhibitor (TAFI, or procarboxypeptidase B) is the precursor of a recently described carboxypeptidase that potently attenuates fibrinolysis. Therefore, we hypothesized that elevated plasma TAFI levels induce a hypofibrinolytic state associated with an increased risk for venous thrombosis. To evaluate this hypothesis, we(More)
We undertook a population-based case-control study to test the clinical importance of a hereditary abnormality in the coagulation system, characterised by poor anticoagulant response to activated protein C (APC), which is associated with familial thrombophilia. The abnormality was detected in 64 (21%) of 301 unselected consecutive patients younger than 70(More)
BACKGROUND Microparticles (MPs) are small vesicles released from cells of different origin, bearing surface antigens from parental cells. Elevated numbers of blood MPs have been reported in (cardio)vascular disorders and cancer. Most of these MPs are derived from platelets. OBJECTIVES To investigate whether atomic force microscopy (AFM) can be used to(More)
BACKGROUND Altered maternal inflammatory responses play a role in the development of preeclampsia and the hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome. We examined whether allelic variants of the innate immune receptors Toll-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain 2 (NOD2), that impair the inflammatory(More)
The relevance of heterozygosity for hereditary protein C deficiency as a risk factor for venous thrombosis has been disputed because heterozygotes without symptoms have been identified among blood donors and relatives of homozygotes. As a result, clinicians do not know whether to offer prophylaxis or not. We have compared thrombosis-free survival in 161(More)
OBJECTIVE It is generally assumed that C-reactive protein (CRP) induces synthesis of tissue factor (TF) in monocytic cells, thereby potentially initiating intravascular blood coagulation. We aimed to elucidate the mechanism of CRP-induced TF expression in monocytes and monocyte-derived macrophages (MDMs) in vitro. METHODS AND RESULTS Monocytes were(More)
INTRODUCTION Extracellular vesicles (EV) are phospholipid bilayer-enclosed vesicles recognized as new mediators in intercellular communication and potential biomarkers of disease. They are found in many body fluids and mainly studied in fractions isolated from blood plasma in view of their potential in medicine. Due to the limitations of available(More)