Learn More
A surface plasmon resonance (SPR) apparatus was used to investigate blood plasma coagulation in real time as a function of thromboplastin and heparin concentrations. The response curves were analyzed by curve fitting to a sigmoid curve equation, followed by extraction of the time constant. Clotting activation by thromboplastin resulted in increased time(More)
An automated procedure for determination of clotting time in whole blood was validated by direct comparison with the reference method, visual clotting time determination. The procedure was based on a 10 Hz free oscillation rheometer (FOR) of our design, the ReoRox 4. Recalcified citrated blood samples (n = 30), clotting in the range 4 to 20 min, were used(More)
Clinical research studies have indicated the possibility of diagnostic strategies for deep venous thrombosis (DVT), strategies which include a step where the diagnosis is excluded by low or undetectable plasma levels of fibrin degradation product D-dimer. In collaboration with two local hospitals in Sweden, three implementations of such a strategy are(More)
In haemostatic and biomaterial research biological processes at surfaces and in the bulk phase of the surface-contacting medium are important. The present work demonstrates the usefulness of the combination of surface plasmon resonance (SPR), sensitive to changes in refractive index at surfaces, and free oscillation rheometry (FOR), sensitive to rheological(More)
It is previously shown that surface plasmon resonance (SPR) can be used to study blood plasma coagulation. This work explores the use of this technique for the analysis of tissue factor induced coagulation, i.e. prothrombin time (PT) analysis, of whole blood and plasma. The reference method was nephelometry. The prothrombin time analysis by SPR was(More)
A two stage method for determination of plasminogen activator inhibitor (PAI) activity in blood plasma is described. In the first stage, an excess of single-chain tissue plasminogen activator (t-PA) is added to plasma. In the second stage, the residual t-PA activity is determined with a plasminogen/chromogenic plasmin substrate assay utilizing poly-D-lysine(More)
Prothrombin time (PT) is clinically important and is used to monitor oral anticoagulant therapy. To obtain PT results in international normalized ratio (INR), the current standardization procedure is complex and involves reference reagents. The PT of diluted plasma samples can be determined with a combined thromboplastin (the Owren-type procedure), but not(More)
We have studied the effects of different platelet agonists on phosphatidylserine (PS) exposure and clotting times in blood without anticoagulants. Similar reductions in clotting time were obtained for collagen, TRAP-6 or calcium ionophore A23187 (50 micro mol/L), in spite of huge differences in PS expression [6.7 +/- 2.4%, 2.3 +/- 0.5% and 99.9 +/- 0.1%,(More)
INTRODUCTION In vivo, initial platelet activation is likely caused by platelet contacts with collagen in the subendothelium or from the small amounts of thrombin formed by the tissue factor/factor VIIa complex. Our aim was to study the coagulative role of ADP released by the platelets after activation with strong stimuli such as collagen and/or thrombin,(More)
We have studied the contribution of platelets to the coagulation of plasma and the effects of activation or inhibition of platelets on the coagulation process in unanticoagulated fresh whole blood (subsequently termed native blood). For this purpose, we have used a free oscillation rheometer (FOR), the ReoRox4, a new instrument that enables noninvasive(More)