Mr. Johnston runs Johnston Associates, a venture capital firm which he founded in 1968 to provide seed capital for start-ups in the biotechnology and healthcare fields.  He has founded numerous public companies including Sepracor, Cytogen (sold to EUSA Pharma), I-STAT (sold to Abbott), Genex and Envirogen (sold to Shaw Environmental), and was instrumental in the early formation of many private companies such as Immunicon (sold to J&J), Praelux (since sold to Amersham/GE), and Targent (sold to Spectrum Pharmaceuticals).  Mr. Johnston served as CEO of Cytogen from July 1988 to April 1989 and as CEO of Praelux (formerly SEQ) from November 1997 to January 1999.  Additionally, he is a member of the Advisory Council of the department of molecular biology at Princeton University, and the Executive Committee of the Friends of the Institute for Advanced Study in Princeton, New Jersey.