Summary
Adequate fibrinogen reactivity is suggested as an additional requirement for specific
fibrinogen reagents, to be added to the well known requirements of protein concentration,
optimum pH, and optimum ionic strength. Reasons and a method for testing are outlined.
A method for the preparation of a specific fibrinogen reagent, deficient in factor
VIII, from BaSO4 adsorbed bovine plasma is described in detail. The method described utilizes either
fresh or regenerated DEAE cellulose as an adsorbent in a non-column chromatographic
adsorption procedure, associated with a dialysis procedure in which the final fibrinogen
product is concentrated and precipitated as a “euglobulin”. The “euglobulin” fibrinogen
precipitate was then dissolved/suspended in buffered saline at a specific pH and NaCl
concentration. Essentially the method can be briefly outlined into 5 separate steps:
1. Dialysis of BaSO4 adsorbed bovine plasma against 0.5% NaCl at pH 6.6 in 0.005 M Imidazole-HCl buffer.
2. Washing of DEAE cellulose with the same type of buffered NaCl solution to specific
conditions.
3. Mixing of the dialyzed BaSO4 adsorbed bovine plasma with the washed DEAE cellulose and separation by centrifugation.
4. Concentration of the cellulose adsorbed plasma as a “euglobulin” fibrinogen precipitate
by dialysis against running tap water.
5. Dissolving of the “euglobulin” fibrinogen precipitate in 0.9% NaCl buffered at
pH 6.8.
Fibrinogen preparations, prepared with the use of regenerated DEAE cellulose were
found to be similar to those prepared by fresh DEAE cellulose in fibrinogen reactivity
and deficiency in factor VIII activity, but were found to have less fibrinogen concentration
than those prepared using fresh DEAE cellulose.
Suggestions were also made for possibly increasing the over-all yield of the fibrinogen
reagent through use of a “washing-elution” procedure.
The procedure that was used for regenerating the DEAE cellulose was also described
in detail and commented upon.