1. Austin Diagnostic Clinic, Austin, Texas, U.S.A.
2. Austin, Bioengineering Program and the Department of Chemical Engineering, Austin, Texas, U.S.A.
3. The University of Texas, Austin, Texas, U.S.A., the University of A Iberta, Austin, Texas, U.S.A.
4. Department of Medicine, and University of Calgary, Austin, Texas, U.S.A.
5. Department of Biological Sciences, Calgary, Alberta, Canada, and the Moncrief-Popovich Research Institute, Austin, Texas, U.S.A.