GB807781A - Plasma fraction and standard plasma preparation and method of preparing same - Google Patents

Abstract

A plasma fraction capable of increasing the activity of thromboplastic material having a prothrombin time of more than 9 seconds is prepared at a low temperature, e.g. - 5 DEG to 5 DEG C., by adding 3 to 5 volumes of a 15 to 30 per cent by volume aqueous solution of methanol, ethanol or a mixture thereof, e.g. at - 5 DEG to - 10 DEG C., at a pH of 4 to 5, to prothrombin-free horse, bovine, human or rabbit plasma, e.g. at 5 DEG to 0 DEG C., stirring and centrifuging the mixture and adding to the separated residue, e.g. at 0 DEG to - 5 DEG C., 3 to 5 volumes of a 5 to 20 per cent aqueous solution of methanol, ethanol or a mixture thereof, e.g. at 0 DEG to - 5 DEG C., at a pH of 6 to 8, containing 4 to 6 per cent by weight of an alkali metal salt of an amino acid having not more than 6 carbon atoms, e.g. alumina, glycine, proline, serine, stirring and centrifuging the mixture, e.g. at 0 DEG to - 5 DEG C., dialyzing the filtered supernatant against distilled water, e.g. at 1 DEG to 5 DEG C., and lyophilizing the supernatant. A standard plasma preparation for use in the determination of the prothrombin time of thromboplastic material is prepared by dissolving 2 to 10 mg. of the plasma fraction per mol. of oxalated bovine plasma. The prothrombin free plasma may be prepared by centrifuging a solution of the plasma in a heparin sodium solution which has been slurried with 2 to 5 per cent barium sulphate. The oxalated bovine plasma is prepared by centrifuging a solution of bovine blood containing 10 per cent by volume of 0.1 molar sodium oxalate solution. The oxalated bovine plasma may be diluted with 0.85 per cent aqueous sodium chloride solution such that the plasma is present in an amount of 60 to 90 per cent by volume of the diluted plasma. The pH may be adjusted by addition of an alkali metal hydroxide, and buffered using a sodium acetate-acetic acid, sodium succinate-succinic acid, sodium acid phthalate-phthalic acid, mono- or di-sodium phthalate buffer. Specification 807,782 is referred to.