Copyright: Elsevier

The role of platelets in blood coagulation

Platelet phosphatidylserine exposure and procoagulant activity in clotting whole blood : different effects of collagen,TRAP and calcium ionophore A23187

We have studied the effects of different platelet agonists onphosphatidylserine (PS) exposure and clotting times in bloodwithout anticoagulants. Similar reductions in clotting time wereobtained for collagen, TRAP-6 or calcium ionophore A23187(50 µmol/L), in spite of huge differences in PS expression[6.7 ± 2.4%, 2.3 ± 0.5% and 99.9 ± 0.1%, respectively (mean ±SD, n = 5)]. Furthermore, the clotting times were much longerfor samples with A23187 exposing the same amounts of PS assamples with collagen or TRAP-6. Annexin V reversed theclotting time reduction, but could not prevent coagulation.Addition of phospholipid vesicles containing 20% PS neitheraffected the clotting times nor induced clotting in recalcified,platelet-free plasma.We conclude that platelet PS exposure is necessary, but notsufficient, for the coagulation amplification observed whenplatelets are stimulated via physiological receptors in a wholeblood environment

Асимптотичне інтегрування системи диференціальних рівнянь з малим параметром і точкою звороту

(UA) Отримано асимптотичний метод інтегрування лінійної системи диференціальних рівнянь з малим параметром.(EN) The obtained asymptotic method of integration linear system of differential equations with small parameter with a turning point

Nietzsche and Heidegger On the Question of Being Human

Heidegger claims in Being and Time that philosophy has continually refused to take up the task of working out a 'natural' conception of the world. (One. where, for example, certain sceptical worries do not arise). My thesis argues that this task is one which emerges clearly from Kant's response to British empiricism - so that Kant's critical philosophy marks the emergence of a new kind of 'naturalism' in which the question of what is distinctively human about human animality is brought to the fore. What is still lacking in Kant, however, is the idea of our t~ching or being responsive to entities themselves which is registered, in Heidegger, by the idea of our 'attunedness'. But, the question of Dasein's precise relation to being human - or, the question of precisely who Dasein is - is problematised, for example, by cases of human children, the physically. disabled and non-human animals. I suggest that Ni~tzsche'sconception of the world as will-ta-power - whose basic unit is the 'drive' - is one which (already) provides the 'natural' conception of the world that (the early) Heidegger is loo~g for. I argue, with . constant reference to Camus' Meursault and Shakespeare's Juliet, that seeing the world as will to power means being able to affirm what the Doctrine of the Eternal Recurrence asks us to affirm.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Platelet phosphatidylserine exposure and procoagulant activity in clotting whole blood : different effects of collagen,TRAP and calcium ionophore A23187

We have studied the effects of different platelet agonists onphosphatidylserine (PS) exposure and clotting times in bloodwithout anticoagulants. Similar reductions in clotting time wereobtained for collagen, TRAP-6 or calcium ionophore A23187(50 µmol/L), in spite of huge differences in PS expression[6.7 ± 2.4%, 2.3 ± 0.5% and 99.9 ± 0.1%, respectively (mean ±SD, n = 5)]. Furthermore, the clotting times were much longerfor samples with A23187 exposing the same amounts of PS assamples with collagen or TRAP-6. Annexin V reversed theclotting time reduction, but could not prevent coagulation.Addition of phospholipid vesicles containing 20% PS neitheraffected the clotting times nor induced clotting in recalcified,platelet-free plasma.We conclude that platelet PS exposure is necessary, but notsufficient, for the coagulation amplification observed whenplatelets are stimulated via physiological receptors in a wholeblood environment

A novel prothrombin time method to measure all non-vitamin K-dependent oral anticoagulants (NOACs)

Background: There is a clinical need for point-of-care (POC) methods for non-vitamin K-dependent oral anticoagulants (NOACs). We modified a routine POC procedure: Zafena’s Simple Simon™ PT-INR, a room-temperature, wet-chemistry prothrombin time method of the Owren-type. Methods: To either increase or decrease NOAC interference, two assay variants were devised by replacing the standard 10 µL end-to-end capillary used to add the citrated plasma sample to 200 µL of prothrombin time (PT) reagent by either a 20 µL or a 5 µL capillary. All assay variants were calibrated to show correct PT results in plasma samples from healthy and warfarin-treated persons. Results: For plasmas spiked with dabigatran, apixaban, or rivaroxaban, the 20 µL variant showed markedly higher PT results than the 5 µL. The effects were even more pronounced at room temperature than at +37 °C. In plasmas from patients treated with NOACs (n = 30 for each) there was a strong correlation between the PT results and the concentration of NOACs as determined by the central hospital laboratory. For the 20 µL variant the PT response of linear correlation coefficient averaged 0.90. The PT range was INR 1.1–2.1 for dabigatran and apixaban, and INR 1.1–5.0 for rivaroxaban. Using an INR ratio between the 20 µL and 5 µL variants (PTr20/5) made the NOAC assay more robust and independent of the patient sample INR value in the absence of NOAC. Detection limits were 80 µg/L for apixaban, 60 µg/L for dabigatran, and 20 µg/L for rivaroxaban. Conclusions: A wet-chemistry POC PT procedure was modified to measure the concentrations of three NOACs using a single reagent.Funding agencies: county of Ostergotland research funds [LIO-609911]</p