Douglass T. Simpson serves as the President and Chief Executive Officer of the Company.  Mr. Simpson joined the Company as Vice President of Business Development in 1992, was promoted to Vice President, General Manager in 1995, to Executive Vice President in 1996 and then to President in February 1998.  Prior to joining the Company, he was a Managing Partner at Venture Marketing Group in Austin, Texas, a health care and biotechnology marketing firm, and in that capacity, served as a consultant to the Company from 1990 until 1992.  From 1984 to 1990 Mr. Simpson was employed by Kallestad Diagnostics, Inc. (now part of BioRad Laboratories), one of the largest diagnostic companies in the world, where he served as Vice President of Marketing, responsible for marketing and business development for this $200 million medical diagnostics company.  Mr. Simpson holds BS and MS degrees in Biology and Chemistry from Lamar University in Beaumont, Texas.