Thromb Haemost 1965; 14(01/02): 032-051
DOI: 10.1055/s-0038-1654852
Originalarbeiten — Original Articles — Travaux Originaux
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A Study of the Cation-and pH-Dependent Stability of Factors V and VIII in Plasma*

HJ Weiss M.D.**
1   Department of Medicine, New York University, School of Medicine
› Author Affiliations

Supported by U.S. Army Research & Development Contract DA-49-193-MD-2375.
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Publication History

Publication Date:
24 July 2018 (online)

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Summary

The in vitro lability of factors V and VIII in plasma has been studied. In agreement with previous reports, an increase in anticoagulant concentration renders both factors more labile (cation-deficient decay), as does an increase in the pH above 7.3 (alkaline-decay). Calcium appears to be the plasma cation which protects factors V and VIII against in vitro loss of activity. The protection obtained by the addition of other divalent cations depended on the type of plasma used. When resin-EDTA plasma was made cation free by dialysis at 4° C and then incubated at 37° C, the rapid loss of factors V and VIII activity could be prevented by prior addition of strontium, manganese and magnesium. In oxalate plasma, nickel, manganese, cadmium and strontium were effective.

The alkaline decay of both factors V and VIII is irreversible. Partial reversibility of the cation-deficient decay was demonstrated for factor V, but not for factor VIII. The temperature coefficient for both the cation-deficient and alkaline decay is 2-3, suggesting an enzymatic rather than a physical reaction.

There was no evidence to implicate thrombin, plasmin or trypsin since inhibitors of these enzymes failed to modify either type of decay.

** Present address: Department of Hematology Mt. Sinai Hospital New York, N.Y.