Appeal No. 1997-3805
Application No. 08/439,602
enabling the method to be more sensitive to the presence of occult blood.
Therefore, one . . . would have found the aniline compounds taught by
Gantzer to work equally as well as the phenol compounds in the method,
composition and kit taught by [Baker] as enhancers for detecting occult
blood.
We have no doubt that the prior art could be modified in a manner consistent with
appellant’s specification and claims. The fact that the prior art could be so modified,
however, would not have made the modification obvious unless the prior art suggested the
desirability of the modification. In re Gordon, 733 F.2d 900, 902, 221 USPQ 1125, 1127
(Fed. Cir. 1984). Here we find no reason stemming from the prior art which would have led
a person having ordinary skill to the claimed method.
In addition to producing “a more intense and readable blue color end point,”
Baker’s phenolic enhancer “degrades and inhibits the more labile peroxidases” which
often contaminate fecal samples and interfere with test results by causing false positive
reactions. Page 2.
Gantzer, on the other hand, is narrowly focused on improving the shelf-life of solid
phase “dip-and-read” devices impregnated with peroxidatively active substances. The
aniline stabilizer is dried onto the device along with, or in addition to, the a peroxide source
and a colorimetric indicator. According to Gantzer, the “anilines are believed to function
not only as inhibitors of chain decomposition of the organic hydroperoxides commonly
used in solid phase assays, but also are advantageous for diminishing or preventing
deleterious interactions between reagents.” Column 4, lines 55-58.
12
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: November 3, 2007