Bibliographical noteFunding Information:
We thank the members of the laboratories for their support and encouragement during the course of this work. These studies were supported, in part, by grants from ValiGen, Inc., Newtown, PA, and by Grants RO1-DK39137 (N.R.C.), RO1-DK46057 (J.R.C.), and PO1-HD32652 (B.T.K.) from the National Institutes of Health.