Blood, 1955, Vol. 10, No. 5, pp. 528-533.
© 1955 American Society of Hematology, Inc.
Electron Microscope Observations of the Platelet-Fibrin
Relationship in Blood Clotting
E. DE ROBERTIS 1
1 Instituto de Investigación de Ciencias Biológicas, Departmento de Ultraest ructura Celular, Montevideo, Uruguay.
The behavior of stretched out human platelets in different stages of blood
clotting has been observed with the electron microscope. In the early stages of
coagulation the morphologically intact platelets apparently act as centers of
orientation and condensation of the fibrin fibrils. This effect is not found in platelets which have previously undergone extensive damage or disintegration. In
more advanced stages of clotting, many platelets remain normal, showing their
attachment to the fibrin, while others have disintegrated and appear as residual
dense bodies.
The probable action of platelets in the retraction and syneresis of the blood
clot is discussed. It is suggested that at the surface of the morphologically intact
platelets, adhesion forces develop which hold and orient the molecular chains of
fibrin increasing the number of interacting junctions and producing syneresis.
On the contrary, the platelets which have suffered an injury which alters these
surface adhesive properties do not interact with the fibrin fibrils and, as a result,
the mechanism of clot retraction is impaired.
Submitted on September 3, 1954
Accepted on October 12, 1954
