Patents Reinstated Due to the Acceptance of a
                      Late Maintenance Fee From 04/03/98
   
Patent           Serial            Filing          Issue          Granted 
Number           Number            Date            Date           Date

4,773,400        07/112,467        10/26/87        09/27/88       04/09/98
4,880,765        07/272,694        11/03/88        11/14/89       04/06/98
5,155,924        07/636,758        01/02/91        10/20/92       04/09/98
5,218,473        07/550,255        07/06/90        06/08/93       04/09/98
5,261,301        07/950,392        09/24/92        11/16/93       04/06/98
5,305,579        07/990,121        12/14/92        04/26/94       04/09/98