[1] Univ Tennessee, Hlth Sci Ctr, Dept Med, Div Gen Internal Med, Memphis, TN 38105 USA
[2] Univ Tennessee, Hlth Sci Ctr, Dept Physiol, Memphis, TN 38105 USA
[3] State Tennessee Div Mental Retardat Serv, Nashville, TN USA
[4] Greenville Hosp Syst, Gardner Ctr Developing Minds, Greenville, SC USA
[5] Vanderbilt Univ, Sch Med, Nashville, TN 37212 USA
[6] Vet Affairs Med Ctr, Memphis, TN USA
[7] Univ Tennessee, Hlth Sci Ctr, Dept Prevent Med, Memphis, TN 38105 USA