Dissociation of clot retraction from platelet granule fusion and degranulation: an ultrastructural study of Reptilase-human platelet-rich plasma clots.

British Journal of Haematology
F De ClerckJ Vermylen

Abstract

Human platelet-rich plasma clots, formed with Reptilase, do not retract. Electron microscopy of such a clot reveals platelets of normal shape and ultrastructural features surrounded by fibrin. When ADP is added before Reptilase, the clot strongly retracts. A sequential ultrastructural study of this process shows that, before visible fibrin formation, the platelets form small clusters and show shape change, granule centralization and pseudopod formation. Upon immobilization of the platelets by fibrin, the pseudopods develop into large cytoplasmatic protrusions, which allow cell contact. During the retraction process, the platelet granules remain intact; some granule fusion only becomes apparent in fully retracted clots. When Thrombofax is added to platelet-rich plasma before Reptilase, the clots formed also retract. With this aggregation inducer, granule fusion occurs earlier and in more platelets. Platelet pseudopod enlargement and fibrin concentration around the platelet mass are similar to that in ADP-treated samples. Inhibitors of granule fusion and secretion (suprofen, indomethacin) do not modify ADP-Reptilase nor Thrombofax-Reptilase clot retraction but reduce the incidence of granule fusion in Thrombofax-Reptilase clots. ...Continue Reading

References

Apr 14, 1972·Biochemical and Biophysical Research Communications·D E Bradley
Jan 1, 1974·Scandinavian Journal of Haematology·F de ClerckG de Gaetano

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Citations

Jun 1, 1982·The Journal of Cell Biology·I CohenJ G White
Mar 1, 1997·The American Journal of the Medical Sciences·M E CarrL Mohanty
Sep 15, 1981·Thrombosis Research·F De ClerckV Van de Velde
Oct 1, 1976·European Journal of Cancer : Official Journal for European Organization for Research and Treatment of Cancer (EORTC) [and] European Association for Cancer Research (EACR)·E Dolfini Morasca
Aug 1, 1976·Thrombosis Research·P Kubisz, S Cronberg
Jan 9, 2008·Vox Sanguinis·L MazzuccoP Borzini

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