[The centennial of blood coagulation doctrine]

For centuries, the mystery surrounding blood coagulation stimulated the curiosity of researchers. The knowledge about this function has increased notably in the last century and has permitted to understand numerous physiopatho logical phenomena in several hemorrhagic and thrombotic diseases, and has made it possible to develop diverse drugs of proved efficacy for prevention and therapy. All this was initiated in 1905, when Paul Morawitz published an extensive monograph on the four factors of blood coagulation known until then (fibrinogen, thrombin, thrombokinase, and calcium). In that work, he proposed a blood coagulation model in two stages: thrombin generation and fibrinogen coagulation. In the 1940s a true golden age in coagulation was started with the results of Quick's prothrombin time test, described in 1936, and since then the most employed coagulation test. Besides numerous factors involved in this function were discovered and classified. The discovery and introduction of heparin and coumarin in the anticoagulant therapeutics opened a measureless panorama for the arrival of new antithrombotic drugs. By the middle of the XX century, the mechanism of coagulation had been practically deciphered and diverse models based on sequential enzymatic function were proposed, called first chain reactions and in cascade reactions later. In the second half of the XX century, numerous regulatory mechanisms of coagulation were identified and diverse laboratory tests appeared that have allowed highly precise diagnoses of a variety of diseases. Blood separation techniques have permitted to produce factor concentrates for clinical use. With the identification of the genes that encode the synthesis of coagulation factors, it has been possible to produce them by means of molecular biology techniques, being the most significant the production of factors VIII, IX, and VII. The present model of coagulation is based on tissular factor activation and the participation of cells, concepts that were already implicit in the classical theory of Morawitz.