Human Plasma as a Source of Prothrombin in the Ac-Globulin Assay.

Abstract

Viscosities measured a t 30" and 6 em H20 t Final concentrations of nucleate and sodium $ Refers to the viscosity of the heated solutions external pressure. chloride O..3rc and 1.0 35, respectively. after dialpis. obtained with potassium chloride and magnesium chloride. Fig. 1 descrilbes 'the effect of heating at various temperatures on the viscosity od aqueous and of salt-containing mixtures with nucleate. Final concentrati'ons of nucleate and of sodium chloride were 0.5 and 1 M, respectively. The period of heating was 20 minutes. .4t temperatures over 85", mixtures of nucleate and salt sometimes yielded a small amount of white precipitate. The structural c'haracter of the viscosity of the nucleate heated in the presence of salt is revealed in Fig. 2.The reversibility of the salt protection was demonstrated by dialysis. Aqueous and saltcontaining solutions of nucleate were heated, dialyzed, made up with water to equal concentrations of nucleate as measured spectrophotometrically in the ultraviolet, and heated again. Several such experiments revealed without exception that after loss of salt by dialysis the nucleate solution suffered a loss in viscosity on heating. A sample experiment is described in Table 11. An interesting finding is that not only does salt protect against the effect of heat, but also apparently against the equally marked effect of dialysis on reducing the viscosity of the nucleate solution.In another series of experiments, water and sodium chloride solutions (2M) were added to equal volumes of heated 1.0% nucleate solutions in water. Only a m'arked decrease in viscosity resulted after addition of the salt solution. The salt must be present while heating the nucleate solution in order to prevent the viscosity drop.Summary. The viscosity of aqueous solutions of sodium thymonzrcleate is reduced both by heating and by addition od sodium chloride and other salts. If, however, the nucleate solution is heated in the presence of a sufficiently high concentration of salt, there is no further decrease in viscosity beyond that induced by the salt. The protective effect of the salt is reversilble, for if the salt is removed ;by dialysis from the heated nucleate-salt mixture, the residual aqueous solution of nucleate again suffers a marked reduction in viscosity on heating.The approach to the problems of blood coagulation from the point of view of study-ing single factors received a major stimulus with ,the development of the 2-stage prothrombin assay by Warner, Brinkhous and Smith

Vitamin K-S (II) in Liver Disease

“…Route of Drug Administration.-Seven¬ teen studies were performed using the oral 48) 15 The rest of the therapeutic program re¬ mained the same. All showed a significant decrease in accelerator activity.…”