1. University of Texas at Houston, M. D. Anderson Hospital and Tumor Institute, Houston, Tex. 77025.
2. Department of Developmental Therapeutics, the University of Texas at Houston, M. D. Anderson Hospital and Tumor Institute, Houston. Tex. 77025.
3. Department of Clinical Chemistry and Laboratory Medicine, the University of Texas at Houston. M. D. A nderson Hospital and Tumor Institute. Houston, Tex. 77025.