STUDIES ON BLOOD COAGULATION

Abstract

Presented in this paper are the results of some fundamental investigations on the technical aspects of the thromboplastin generation test, firstly described by Biggs and Douglas in 1953, and on the nature of the coagulation factors involved in the formation of an active prothrombin converting principle or blood-thromboplastin by employing thisva luable technique.For the present study, some modifications in the thromboplastin generation test as originally described are used: the use of BaSO4 instead of Al (OH)3-gel for the absorption of prothrombin, numerical standardization of the platelet suspension.1) Five factors, platelets, anti-hemophilic globulin, plasma thromboplastin component, and factor V and VII in the presence of CaCl2, seemed to be necessary for blood-thromboplastin formation.2) Experiments with brain extract have suggested that brain extract is not itself thromboplastic but can be converted to thromboplastin after interaction with factor V and serum fraction.3) The amount of blood-thromboplastin generated is quantitatively related to the number of platelet, concentration of anti-hemophilic globulin. The greatest effect on the speed of blood-thromboplastin formation, on the other hand, is related to the concentration of anti-hemophilic globulin.4) Platelet suspension may be kept for about a week without any significant loss of activity, when stored in refrigerator at-1°C. This makes it possible to run the thromboplastin generation test as a routine screening test.5) The adsorbed plasma and the serum should be diluted at least half an hour before the test are performed, though the explanation of this phenomenon has not yet been made.6) Relative lack of factor V in the reacting mixture has little influence on the thromboplastin generation test in the presence of fresh platelets. This may be due to platelet factor 1.7) The activity of blood-thromboplastin formed in reacting mixture disappears rapidly. If a buffer is introduced in the reactives, a much more stable activity can be obtained. Anti-hemophilic globulin and factor V are consumed in the course of blood-thromboplastin formation.8) Concentration of thrombin formed in the reacting mixture of the thromboplastin generation test is very low and is too small in amount to clot substrate plasma. Small amount of thrombin accelerates the speed of blood-thromboplastin formation in the original test, but no such effect has been observed in the presence of brain extract. It may be inferred, therefore, that the accelerating action of thrombin takes place at an initial stage of blood-thromboplastin formation.