Dr. McCallum is a professor and founding chairman of the Department of Internal Medicine, Texas Tech University Health Sciences Center. He also serves as director of the Center for Neurogastroenterology and GI Motility and Functional Bowel Disorders. He is a pioneer in gut electrophysiology and developed the concept of electrical "pacing" of the stomach to treat gastroparesis and nausea and vomiting, particularly related to diabetes mellitus. He has contributed to major advances in understanding and management of cyclic vomiting syndrome in adults, "dumping syndrome," and rumination syndrome and has revolutionized the field of gastroparesis and functional dyspepsia by developing and reporting a new technique to non-surgically obtain gastric smooth muscle tissue by endoscopic ultrasound biopsy. Dr. McCallum was recently awarded funding from the International Foundation for Functional Gastrointestinal Diseases (IFFDG) to study a new therapy, transcutaneous electrical stimulation, in patients with nausea, vomiting, and idiopathic gastroparesis.