Appeal No. 1997-1093
Application No. 08/272,281
Furthermore, "[t]he use of aluminum hydroxide to adsorb fibrinogen, an optional method
claimed, is taught by Mathews" (answer, page 4, lines 17-18).
However, the method taught by Kotitschke is not "nearly identical" to that claimed.
Kotitschke uses a single adsorption onto protein adsorbing anion exchangers, e.g.,
DEAE-Sephadex or DEAE-cellulose, to remove factors II, VII, IX and X, as well as
antithrombin III, from a citrated plasma cryoprecipitate, resulting in a supernatant
containing fibrinogen (Fig. 4; col. 4, lines 16-22; col. 6, lines 31-45). The fibrinogen is then
adsorbed on colloidal silica, separated from the supernatant, eluted with buffer and
ultrafiltered with subsequent alcohol fractionation to obtain coagulable fibrinogen (Fig. 4;
col. 5, lines 50-56).
Apparently recognizing the difference in methodology, the examiner opines that "it
is well known in the art to use as many purification [i.e., adsorption] steps as are necessary
in order to obtained [sic] a product with the desired purity" (answer, page 5, lines 5-7).
However, the claimed invention does not require a fibrinogen solution of stated minimum
purity, but rather a stable fibrinogen solution which maintains its ability to function when
stored at 4-25EC for four weeks. Purity and stability are not synonymous. Purity refers to
lack of contaminants or impurities, while stability refers to a resistance to chemical change
or physical decomposition.
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