Abstract
Dialysis of blood plasma, it has been presumed, removes only one component essential to the blood clotting mechanism, namely, calcium. However, during the course of certain experiments in which plasma was very thoroughly dialyzed, the authors observed that when the plasma proteins were redissolved in a saline solution containing an adequate amount of calcium, no clot was formed for 24 or 48 hours. If to this artificial plasma there is added a small portion of the ultrafiltrate of whole blood or serum, the formation of a firm clot is induced within an hour or less.
This observation seems to indicate the presence of a dialyzable substance in the blood other than calcium ion which is concerned in the blood clotting process. The substance appears to be an organic compound since the power of accelerating blood clotting is lost if the serum ultrafiltrates are charred.
Either citrated or oxalated plasma may be used to demonstrate this phenomenon. However, a thorough dialysis of the plasma is required, ordinary dialysis against tap water not being sufficient. In the present experiments the dialysis was carried out in a rocking dialyzer 1 at the temperature of 5° against running distilled water. After about 2 to 3 days of dialysis, an artificial plasma is prepared by adding sodium chloride, sodium bicarbonate, sodium phosphate, magnesium chloride, and glucose in the amounts required to produce the concentration found in blood. The pH is adjusted to 7.4 by bubbling in CO2. Calcium is not added until it is desired to initiate a clotting experiment. The plasma proteins disperse completely in the above menstrum, giving a solution which is no more turbid than the original plasma.
If properly dialyzed, such an artificial plasma shows no sign of clotting for 24 hours or longer after calcium has been added.
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