1. From the Department of Biological and Biomedical Sciences (D.S., S.B., S.R.H., A.N., S.K., P.F.), Aga Khan University, Karachi, Pakistan; Section of Neurology (S.S.), Department of Medicine, Aga Khan University, Karachi, Pakistan; Liaquat National Hospital (M.K.A.), Karachi, Pakistan; and Section of Gastroenterology (M.K.A.), Department of Medicine, Aga Khan University, Karachi, Pakistan.