Appeal No. 1996-1811
Application No. 08/169,968
be rapidly obtained from the blood sample added with heparin without affecting the results
of blood biochemistry tests” (page 4, lines 7-9). The blood sample clotted within 30
minutes (page 7, line 10).
Table 4 (page 132) in Lewis compares the effect of various clotting reagents on
citrated normal and citrated heparinized plasma. The clotting reagents are (1) bovine
thrombin, (2) human thrombin, (3) Crotalus h. horridus snake venom, (4) Arvin
(Ancestrodon rhodostoma) snake venom, (5) bovine thrombin combined with BaCl and
2
(6) bovine thrombin combined with protamine. According to Lewis,
Heparin inhibits the thrombin clotting of fibrinogen but not the clotting
caused by some snake venoms. Heparin is adsorbed from citrated plasma
onto insoluble barium citrate, which is formed when barium chloride is added
to citrated plasma. Heparin is neutralized by protamine sulfate. [Page 132,
second full paragraph.]
JP 61-53567 describes preparing a thrombin-like enzyme from Trimeresurus
okinavensis snake venom for use as a blood coagulation enhancing agent (page 4).
Approximately 1.5 µg thrombin-like enzyme (i.e., 50 µg/ml x 0.30 µl used) can coagulate 5
ml of normal human blood or heparinized blood within 20 to 25 minutes (page 6).
According to the examiner, “[t]he references disclose only the use of venom alone
or protamine alone or thrombin in combination with protamine to clot heparinized blood or
plasma” (answer, page 4, last sentence). Thus,
... it is prima facie obvious to combine two or more ingredients each of which
is taught by the prior art to be useful for the same purpose in order to form a
- 4 -
Page: Previous 1 2 3 4 5 6 7 8 9 10 Next
Last modified: November 3, 2007