Abstract
For many years it has been known that a certain strain of swine demonstrates an abnormality of blood coagulation similar to that found in human hemophiliacs. The genetics of this abnormality and its mechanism have been extensively studied. 1 , 2 , 3
Working with this strain of swine, Muhrer, Eogart and Hogan 4 have developed a method of testing platelet fragility. It is the purpose of the presenit study to determine (1) whether the method is applicable to the determination of platelet fragility in man, and (2) whether human platelets react similarly to those of swine.
The method resembles that used for testing erythrocyte fragility. Platelet-rich plasma is obtained by moderate centrifugation of whole blood, drawn with special precautions to minimize trauma to the formed elements. The blood is drawn through a petrolatum-lined No. 20 MeCrae needle directly into cold parafinned centrifuge tubes containing sodium citrate. This plasma is added to various hypotonic saline solutions, recalcified, and the time of coagulation measured. It is assumed that the mechanism of coagulation is the classical 2-stage process postulated by most workers in the field, and that coagulation time is quantitatively related to the speed of thrombin formation, which is in turn directly dependent upon the amount of thromboplastin released by platelets. One assumes further that if platelet-rich plasma exposed to hypotonic solutions clots faster than normal plasma, this is due to a more complete lysis of platelets. Conversely, if 2 different specimens, after similar exposure to saline solutions of the same tonicity, have different dotting times, there is presumably a difference in platelet fragility.
Critique of Method. (1) To determine Whether the effect of the hypotonic solutions was on some phase of the clotting mechanism other than the platelets, the specimens, after exposure to the various saline solutions, were all brought up to 0.9% NaCl, prior to re-calcification!. Under such circumstances, clotting occurred in a normal saline solution. As is shown in Fig. 1
Get full access to this article
View all access options for this article.