Evan T. Keller, William B. Ershler, and Chawnshang Chang

The Institute on Aging and the Department of Human Oncology, University of Wisconsin, Madison, WI 53706, USA.

Received 01/16/96; Accepted 02/22/96; On-line 03/01/96

This work was supported by NIH grants AG00213 (WBE), AG00451 (WBE), and CA55639 (CC).