Dicoumarol treatment in oxen induces the production of an abnormal, inactive prothrombin variant that differs from normal prothrombin in its calcium-binding and adsorption properties.
Suggests dicoumarol induces inactive prothrombin variants in animals; leaves open whether similar mechanisms apply in human anticoagulation.
An abnormal prothrombin was identified with immunochemical methods in the plasma from dicoumarol-treated oxen. During dicoumarol treatment this abnormal prothrombin increased in concentration, while the concentration of normal prothrombin decreased. In contrast with normal prothrombin, this abnormal prothrombin is not adsorbed to barium citrate, and it remains apparently unchanged in samples in which normal prothrombin has been activated. After removal of normal prothrombin from the plasma by adsorption to barium citrate, the dicoumarol-induced prothrombin was purified by a procedure involving ammonium sulfate fractionation, chromatography on DEAE-cellulose, DEAE-Sephadex, and hydroxylapatite and gel filtration on Sephadex G-100. The purified material was homogenous by gel filtration and polyacrylamide gel disc electrophoresis. It has the same main antigenic determinants as normal prothrombin but no prothrombin activity. The electrophoretic mobility of the abnormal prothrombin, unlike that of normal prothrombin, does not vary with the concentration of calcium in the buffer.
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Stenflo et al. (1972) studied this question.
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