New Data on Hageman Factor and Plasma Thromboplastin Antecedent: The Role of ‘Contact’ in the Initial Phase of Blood Coagulation

WE havc previously shown (Soulicr, Wartcllc and Minachi, 1958, 1959), that Hagcniaiitrait plasma is iiicapablc of activation by glass but is sciisitivc to thc addition of glass-activated normal plasma. Plasiiia deficient in plasnia thromboplastin antcccdctit (PTA), on the other hand, is cayablc of being activatcd by glass but is iiisciisitivc to the addition of glass-activatcd normal plasma. W e havc thcrcforc idciitificd the ‘contact factor’ of iioriiial plasma with thc Hagcnian factor (HF) and havc postulatcd that glass-activated H F and PTA react together to form thc ‘third prothromboplastic factor’ (AHF-C). We have also shown thc apparent activation by glass of antihacmophilic factor B (AHF-B, Christmas factor, Factor IX) to be dcycndcnt 011 thc activation of H F by glass. In this papcr, wc rcport studies with various other activating agcnts which confirm and cxtciid these observations.