Platelet aggregation: newly quantified using non-empirical parameters
Nichols, A.R.; Bosmann, H.B.
Thrombosis and Haemostasis 42(2): 679-693
1979
ISSN/ISBN: 0340-6245 PMID: 116385 Document Number: 146856
New methodology for a quantitative description of ADP-induced human blood platelet aggregation in vitro was presented. The method used electronic particle size analysis to determine relative amounts of and distribution of sizes among platelets and aggregates after rapid termination of the events of ADP-induced aggregation by glutaraldehyde. Glutaraldehyde preserved the state of platelets and aggregates in suspension unchanged for up to 48 h. Descriptions of platelet aggregate sizes and amounts at many points during reversible and irreversible aggregation at 37.degree. C as they occurred in the Platelet Aggregometer were discussed. A new model of reversible platelet aggregation emerged revealing previously unrecognized details of both the aggregation and disaggregation phases of the phenomenon, and establishing that disaggregation was not simply the mirror image of aggregation. Reactive proportions of the platelet population under conditions of ADP-induced reversible and irreversible aggregation were very similar, strongly suggesting that other factors were responsible for the large differences in aggregation rates and resulting aggregate sizes. Correlations between Platelet Aggregometer parameters and aggregate size distributions were considered, and the 1st report of a correlation between average platelet composition of particles in the aggregated suspensions and absorbance change as recorded by the Aggregometer was made. The relationship between particle concentration of a suspension of platelets and aggregates and the suspension absorbance was non-linear. Heretofore unrecognized limitations of the Platelet Aggregometer were revealed. Absorbance as measured by the Aggregometer does not uniquely represent the magnitude of formed aggregates.