The Fibrinotic Index and Evidence for a Balanced Regulation of Coagulation Activities*

Summary

The fibrinogen, plasma antithrombin, and thrombin activity curves of twenty-four normal individuals were determined under carefully controlled conditions of analysis. From these determinations plasma prothrombin and thromboplastic activities were calculated. These activities were defined in kinetic terminology and a theoretical rate of fibrination in plasma was calculated and used as a basis for comparing plasmas. Compensatory relationships were found among the various activities. Thus, low values of thromboplastic activity were associated with increased concentrations of prothrombin and fibrinogen; the effect of the latter activities in increasing the potential of plasma for fibrination was moderated by an increase in antithrombin activity.

The fibrin-forming potential of each plasma was calculated relative to the mean value for all plasmas, to furnish a fibrinotic index. The latter was relatively constant in spite of wide variations in discrete activities, indicating that a physiological balance is maintained among those coagulation factors responsible for fibrination.

• References

• 1 Astrup T. The Haemostatic Balance. Thrombos. Diathes. haemorrh. (Stuttg) 02: 347 1958;
• 2 Jensen H. Dynamic Concept of Fibrin Formation and Lysis in Relation to Haemorrhage. and Thrombosis. Exp. Med. Surg. 14: 189 1956;
• 3 Alexander B. Blood Coagulation and Thrombotic Disease. Circulation 25: 872 1962;
• 4 Roos J. Blood Coagulation as a Continuous Process. Thrombos. Diathes. haemorrh. (Stuttg) 01: 471 1957;
• 5 Hjort P. F, Hasselback R. A Critical Review of Evidence for a Continuous Hemostasis in vivo. Thrombos. Diathes. haemorrh. (Stuttg) 06: 580 1961;
• 6 Grannis G. F, Kazal L. A, Tocantins L. M. The Spectrophotometric Determination of Thrombin Activity in Plasma. Thrombos. Diathes. haemorrh. (Stuttg) 13: 330 1965;
• 7 Kazal L. A, Grannis G. F, Tocantins L. M. The Reactions of Thrombin with Fibrinogen and Plasma Antithrombin. Thrombos. Diathes. haemorrh. (Stuttg) 13: 343 1965;
• 8 Grannis G. F, Kazal L. A, Tocantins L. M. The Kinetics of Thrombin Activity in Recalcified Blood Plasma. Thrombos. Diathes. haemorrh. (Stuttg) 13: 361 1965;
• 9 Blombäck B. On the Properties of Fibrinogen and Fibrin. Arkiv. Kemi. 12: 99 1958;
• 10 Lever W, Gurd F, Uroma E, Brown R, Barnes B, Schmid K, Schultz E. Determination of Protein Components in Human Plasma. J. Clin. Invest 30: 103 1951;
• 11 Ezekiel MJB. Methods of Correlation Analysis. 2nd ed.,. 148 J. Wiley and Sons, Inc; New York, N.Y: 1950