Ex parte HEIMBURGER et al. - Page 2

                   Appeal No. 1997-3501                                                                                                                             
                   Application No. 08/253,232                                                                                                                       

                            Claim 24 is illustrative of the claims on appeal and reads as follows:                                                                  
                            24.       A process for the preparation of a pasteurized and purified von Willebrand                                                    
                   factor concentrate, which comprises:                                                                                                             
                            a)        preparing a solution selected from the group consisting of cryoprecipitate,                                                   
                   Cohn fraction I, a supernatant of a cell culture and an extract of a cell culture, said solution                                                 
                   having a pH of 5.5 to 7.3, and containing von Willebrand factor (vWF) as a complex with F                                                        
                   VIII:C, a carbohydrate at a concentration of 5-30% w/w, calcium ion, and amino acids;                                                            
                            b)        treating said solution with an anion exchanger to which F VIII:C binds to                                                     
                   obtain a pasteurized von Willebrand factor concentrate free of F VIII:C;                                                                         
                            c)        treating said von Willebrand factor solution free of F VIII:C with 0.5 to 3 mol/l                                             
                   glycine to precipitate proteins from said solution;                                                                                              
                            d)        removing said protein precipitate from said solution to form a glycine                                                        
                   supernatant solution containing von Willebrand factor;                                                                                           
                            e)        adding NaCl at a concentration of 2-15% w/v to said glycine supernatant                                                       
                   solution to precipitate von Willebrand factor; and                                                                                               
                            f)        recovering precipitated von Willebrand factor.                                                                                

                            The prior art references relied upon by the examiner in rejecting the                                                                   
                   appealed claims are:                                                                                                                             
                   Kotitschke et al. (Kotitschke)                            4,272,523                             Jun.   9, 1981                                   
                   Mitra et al. (Mitra)                                      4,543,210                             Sep. 24, 1985                                    
                   Mathews et al. (Mathews)                                  4,743,680                             May 10, 1988                                     
                   British Patent Application                                                                                                                       
                   Costello                                                  2 079 292                             Jan.  20, 1980                                   


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