Applications d’une méthode photométrique à l’étude des phénomenes de coagulation et de fibrinolyse

Overall study of the in vitro plasma clotting system in an invertebrate, Liocarcinus puber (Crustacea Decapoda): considerations on the structure of the Crustacea plasma fibrinogen in relation to evolution

An overall study of the in vitro plasma coagulation system in the crab Liocarcinus puber has been carried out using various analytical methods, namely thromboelastography, spectrophotometrical examination, and a new one based on changes of the mechanical impedance of the developing clot. From the results reported here the clotting pattern in this species appears surprisingly complex for an invertebrate and unexpectedly closer to that of the vertebrates. Indirect evidences suggest that the fibrinogen polypeptide chains in this species and very likely in the other crustacean, are very different from those of the vertebrates. This would imply that crustacean and vertebrate fibrinogen would have diverged from one another in a far remote past, far beyond the individualization of the vertebrate alpha chain, that is, over 1.5 million years ago.

An autoantibody with potent antithrombin activity whose action could be inhibited by toluidine blue or methylene blue

A 41-year-old man with posthepatic liver cirrhosis and bleeding tendency was found to have a circulating anticoagulant with potent antithrombin activity. The thrombin time of the patient's purified fibrinogen was normal. This anticoagulant was residing in the patient's IgG fraction, and his IgG fraction could prolong the thrombin time of purified fibrinogen, suggesting that this circulating anticoagulant was an antibody. No heparin was detected in the patient's plasma. However, the antithrombin activity of this anticoagulant could be neutralized by toluidine blue or methylene blue ex vivo.

Kinetics of plasma coagulation and lysis I: Basic kinetic model for time course of coagulation-lysis systems and its potential application to clinical studies

The time courses of coagulation and coagulation-lysis were spectrophotometrically monitored after the addition of thrombin or thrombin-streptokinase to plasma, diluted 1:5 with normal saline, obtained from normal and presumably abnormal subjects. The kinetics of clotting, after an initial lag period of 0.5-1.5 min, demonstrated essentially first-order dependence on the amount of fibrinogen available to form the clot, and the asymptotic absorbance was independent of thrombin concentration. The rate of clotting was a function of added thrombin, and the ratios of the rate constants at 2.5 and 1.25 units of thrombin/ml of undiluted plasma were 1.65 +/- 0.03 SEM. At early times, the coagulation-lysis curve with thrombin-streptokinase could be superimposed on the clotting curve with thrombin alone for a given plasma with minor compensation for variable lag times. Subsequently, the curves diverged; lysis was monitored by the decrease in absorbance of the coagulation-lysis system. The rate of fibrinolysis increased with streptokinase concentration and was a function of the extent of lysis, and it permitted the description of the kinetics of lysis by a pseudoautocatalytic mechanism where the bimolecular rate constant appears proportional to streptokinase concentration. Ranges of clotting and lytic parameters for the plasma of normal subjects are given, and their potential use in diagnosing abnormalities is described.