Thromb Haemost 1987; 58(02): 682-685
DOI: 10.1055/s-0038-1645955
Original Article
Schattauer GmbH Stuttgart

Free Platelet Count and Size Distribution During C1q Inhibition of Collagen-Induced Platelet Aggregation

Gyorgy Csako
1   The Clinical Pathology Department, Clinical Center, National Institutes of Health, Bethesda, Md., USA
,
Eva A Suba
2   The Naval Medical Research Institute, Bethesda, Md., USA
› Author Affiliations
Further Information

Publication History

Received 29 September 1986

Accepted after revision 17 March 1987

Publication Date:
27 June 2018 (online)

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Summary

Electronic free platelet counting was more sensitive than turbidimetry to detect collagen-induced platelet activation in human platelet-rich plasma. Purified human Clq exhibited a greater inhibitory effect on collagen-induced platelet aggregation in turbidimetry than free platelet counting. Because the change from small to large platelet aggregates is responsible for the continuing increase in light transmission, Clq was likely more capable of blocking the formation of large platelet aggregates than the formation of small aggregates from single platelets. The iattr uf change by cullagcn in light tiansmissiun and fiec platelet count was reduced in the presence of Clq but the timing of the peak response remained the same. Electronic platelet sizing revealed that the volume of single platelets transiently increased during the turbidimetric “lag phase”. The mean, mode and median volume of the remaining free platelets then decreased, suggesting a selective loss of large, functionally more active platelets and/or platelet degranulation. Clq had no effect on the volume increment during the “lag phase”, but reduced the subsequent fall in the volume of free platelets.