Blood coagulation factors in total body irradiation.

HERBERT S. SLSE, JACQUES GAUTHIEB, ROBERT BECKER AND JOHN Boz. c n H EMORRHAGE has been an important and ominous sign in victims of irradiation effects. Although its occurrence coincided with a period of intense thrombocytopenia, Allen and Jacobson1 in experimental observations in dogs observed a circulating heparin-like anticoagulant, and Allen2 concluded that it played an important role in this hemorrhagic state. The reports of Cronkite,3 Holden et al.4 and Jackson et al.5 indicated that the presence of a circulating anticoagulant was inconstant and they disclaimed any important role played by it. Their studies showed that with the fall in platelets there was an increase in the whole blood clotting time, slow to absent clot retraction, lysis of whole blood clots in some animals, an increase in the levels of fibrinogen from the eighth day on, and no change in the prothrombin time. Furthermore, studies by Cronkite et al.,6 Woods et al.7 and Hjort, Perman and Cronkite5 clearly show that the hemorrhagic state in the experimental animal is related to thrombocytopenia and not to a circulating anticoagulant. No abnormality of the coagulation factors has as yet been reported. Cronkite, I acobs and Schork,9 however, made the observation that the platelets in the degenerative phase of the thrombocytopenic period were less active in the utilization of prothrombin than the platelets in the regenerative phase. Jacobs, Cronkite and White’#{176} observed that the evolution of SPCA ( active factor VII) was imparied in the irradiated dog but that more than normal amounts were evolved when prothrombin conversion was accelerated by artificial means such as agitation, thrombin or thromboplastin. This effect in light of later developments in the field of coagulation can be interpreted as failure to generate a normal amount of the plasma thromboplastic material due to a lack of the contribution to this complex aggregate by the platelets. Holden et al.4 observed a decrease in the sedimentable thromboplastic material of plasma. The opportunity to study the effects of total body irradiation in man became available when eight men were exposed to radiation as a result of the Y-12 accident at Oak Ridge, Tennessee, June 16, 1958.11 In three cases the calculated exposure was less than 100 r. The results of studies of the coagulation mechanism on the five who received high dose irradiation (cases .A-E) are reported herewith.