b'Gastroenterologist Gastroenterologist Sekou Rawlins, MD, talks about colon cancer screening Sekou Rawlins, MD, talks about colon cancer screening. Infectious disease expert. Infectious disease expert Timothy Endy, MD, discusses deadly infections that may result from drug abuse. Timothy Endy, MD, discusses deadly infections that may result from drug abuse. Pediatric gastroenterologist Pediatric gastroenterologist Aamer Imdad, MBBS, explains the role of vitamin A Aamer Imdad, MBBS, explains the role of vitamin A. .'