[1] Univ Texas Hlth Sci Ctr San Antonio, San Antonio, TX 78229 USA
[2] South Texas Vet Hlth Care Syst, San Antonio, TX USA
[3] Univ Colorado Hlth, Colorado Springs, CO USA
[4] Stanford Univ, Palo Alto, CA 94304 USA
[5] Univ Texas Hlth Sci Ctr San Antonio, Audie L Murphy Mem Vet Hosp, San Antonio, TX 78229 USA
[6] UT Hlth Sci Ctr, San Antonio, TX USA