Abstract
Conclusion
Stability studies of fibrinopeptide A in plasma, an ultrafiltrate of plasma, urine and buffer were conducted using a radioimmunoassay method to measure immunoreactivity of the peptide. The peptide was found to be unstable in plasma at 25 and 37° with 50 to 65% loss of activity at 24 hr and 85% loss of activity after 7 days. Similar loss of FPA activity was also noticed in an XM 50 ultrafiltrate of plasma and in urine. Of various proteolytic inhibitors tested only EDTA in concentrations of 40 μmoles/ml was able to completely stabilize the peptide against loss of activity. Freezing of the peptide in plasma at —10° was also associated with complete stability of FPA activity for at least 7 days.
This work was supported by grants from the National Institutes of Health (NHLI) (HL 10999, HL 14236, HE 05741) and the New York Heart Association. H.L.N. is a recipient of Career Development Award HE 46355 and G.D.Q. is supported by Hematology Training Grant AM 05231.
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