Date of Award

Spring 1958

Document Type



Life & Environmental Sciences

First Advisor

Donald Waldhalm


Rate and extent of clot retraction are determining factors in either causing or preventing damage in vivo and are in vitro useful in diagnosis of various diseases. In clinical medicine the importance of clot retraction has been largely ignored. The therapy applied in cases of venous thrombosis is at present administration of an anticoagulant. This serves to prevent intravascular coagulation of the blood. This therapy is of course quite effective, but in certain cases it presents complications. When a large clot has been formed in such a position that it severely impairs or prevents circulation and cannot be removed by dissolvement it must be eliminated in surgery. In cases of people prone to thrombosis this is not easily done. The administration of anticoagulants must be stopped so that the blood will regain its normal clotting power so as to prevent excessive blood loss during surgery. This may give rise to other thrombosis. However the retraction of a preformed clot, not the coagulation of blood itself, causes venous thrombosis. Thus if it were possible to prevent retraction and yet permit formation of the clot the problem could be eliminated.

The information and observations in this thesis serve to demonstrate that clot retraction can be controlled.

Another phase of clot retraction whose importance is not as yet fully appreciated is its use in diagnosis of hemorrhagic diseases. In order that retraction will take place platelets must be present in sufficient quantity and functioning properly. The coagulation mechanism, both in vivo and in vitro, is not yet fully understood. However it is possible to demonstrate several phases in the process. Platelets are important in all phases. They can be substituted for by certain other compounds in all but the final phase. That is clot retraction. Without platelets there is no retraction.