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AGGREGATION AND ACTIVATION OF HUMAN BLOOD PLATELETS
Author(s) -
Fantl P,
Sweet B
Publication year - 1966
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1966.14
Subject(s) - platelet , chemistry , optical density , coagulation , thrombin , clotting factor , clotting time , adenosine diphosphate , platelet rich plasma , biophysics , medicine , biochemistry , platelet aggregation , biology , ophthalmology
Summary Venous blood was taken with the least trauma and contact before addition of citrate. Optical density was a measure of platelet changes in plasma after the addition of varying amounts of adenosine‐diphosphate (ADP) and during the initial stages of the clotting process. Reduction of optical density of platelet‐containing plasma is due to aggregation. This is reversible at low concentrations of ADP. Activation is defined as irreversible reduction of optical density and of shortening of plasma clotting time. Before aggregation a slight increase in optical density occurred in platelet‐containing plasma obtained from blood citrated after up to 10 min. following venesection; this is followed by a reduction of optical density and finally activation of the clotting process. Normal blood collected in glass can be stored approximately 6 min. and storage in siliconised tubes can be extended to 20 min. before reduction in optical density is noticed. Platelet‐containing plasma from a patient with von Willebrand's disease behaved normally, and platelet‐containing plasma from a patient with congenital factor XII deficiency (Hageman trait) behaved as normal blood stored in siliconised containers. Aggregation and activation occur in close, association with the clotting process. Platelets ruptured by freezing of platelet‐containing plasma and also thrombin deflbrinated plasma release only a small fraction of aggregating material. Response of platelets to ADP and also in the clotting process vary greatly despite precautions taken to obtain undamaged platelets.