Department of Biological and Biomedical Sciences, Faculty of Health Sciences, The Aga Khan University, Karachi, Pakistan & Department of Gastroenterology and Hematology, Faculty of Medicine, University of Toyama, Sugitani 2630, Toyama, Japan. Department of Basic Medical Sciences, College of Medicine, King Saud bin Abdulaziz University of Health Sciences, Jeddah, Kingdom of Saudi Arabia. Department of Internal Medicine, Jinnah Medical College Hospital, Korangi, Karachi, Pakistan.