Professor of Medicine
Chief, Division of Gastroenterology
Dr. Zuckerman graduated Phi Beta Kappa from the University of Rochester and went to Tufts University School of Medicine in Boston. He did his residency in medicine at Baystate Medical Center (Tufts) and his fellowship in gastroenterology at the Albert Einstein College of Medicine in New York.
Professional society membership includes being a fellow of the American Society for Gastrointestinal Endoscopy, the American College of Gastroenterology, the American Gastroenterological Association, the Infectious Diseases Society of America, and a member of the American Neurogastroenterology and Motility Society and the American Association for the Study of Liver Disease. He has been a member of the Educational Affairs Committee and the Practice Parameters Committees of the American College of Gastroenterology, the Standards of Practice Committee of the American Society of Gastrointestinal Endoscopy, and was involved in the publication of numerous national guidelines on gastrointestinal endoscopy. He is the author over 110 publications in the field of gastroenterology. Research interests include irritable bowel syndrome, gastroesophageal reflux disease, non-steroidal anti-inflammatory drugs and the gastrointestinal tract, and infectious complications of liver disease.
Dr. Zuckerman’s clinical interests include functional gastrointestinal disorders such as irritable bowel syndrome, gastrointestinal bleeding, diseases of the small bowel, colon cancer screening, and the endoscopic procedures of video capsule endoscopy and small bowel endoscopy.
Associate Program Director
Dr. Elhanafi is board certified in both internal medicine and gastroenterology. He is an assistant professor of medicine and the associate program director of the gastroenterology fellowship program at Texas Tech University Health Sciences Center El Paso. Dr. Elhanafi graduated from the University of Mansoura School of Medicine in Egypt. He did his internal medicine residency at Texas Tech University Health Sciences Center El Paso. He completed his fellowship in gastroenterology and hepatology at the University of Pennsylvania in Philadelphia and subspecialty fellowship training in advanced and interventional endoscopy at the Mayo Clinic in Scottsdale, Arizona.
Dr. Elhanafi is a member of the American College of Gastroenterology, American Gastroenterological Association and the American Society for Gastrointestinal Endoscopy as well as the American College of Epidemiology. Dr. Elhanafi has been appointed to the Standards of Practice Committee of the ASGE. Among his honors and awards are Alpha Omega Alpha Honor Society membership, the Frank Brooks Research Award for Excellence in GI Research from the University of Pennsylvania, the AGA Young Investigator Research Achievement Award, Resident Award from the Southern Society for Clinical Investigation, and the Outstanding Research Award from Texas Tech University Health Sciences Center El Paso.
Dr. Elhanafi’s clinical interests are in pancreatobiliary diseases, and precancerous and cancerous lesions of the gastrointestinal tract. He specializes in advanced diagnostic and therapeutic endoscopic procedures, including endoscopic ultrasound, ERCP and cholangioscopy, balloon-assisted enteroscopy, luminal stent placement, endoscopic mucosal resection, and complex polypectomy. His research focuses on prevention and treatment of gastrointestinal cancers, with a particular interest in using novel endoscopic techniques to diagnose and treat these diseases.
Professor of Medicine
Division of Gastroenterology
Dr. McCallum, a native of Brisbane, Australia, attended the University of Queensland and the Queensland Medical School, earning his bachelor's degree and his M.D. He served a rotating internship at the Charity Hospital in New Orleans LSU service, and his residency in categorical internal medicine at Barnes Hospital, Washington University in St. Louis, Missouri. Dr. McCallum had fellowship training in gastroenterology at the Wadsworth Veterans Hospital and the University of California in Los Angeles. Following his fellowship, he was appointed, director of GI endoscopy and assistant professor at UCLA. In 1976, Dr. McCallum went to Yale University School of Medicine, Yale-New Haven Veterans Administration Hospital where he served as director of the gastroenterology diagnostic laboratories and rose to associate professor.
Dr. McCallum was recruited to the University of Virginia in September 1985 to become the Paul Janssen Professor of Medicine, and chief of the division of gastroenterology, hepatology, and nutrition for ten years. He then accepted the position of professor of medicine, chief of gastroenterology and hepatology at Kansas University Medical Center where he was also director of the Center for GI Nerve & Muscle Function & GI Motility. He was elected to the American Society for Clinical Investigation, and is also a fellow of the American College of Physicians, the Royal Australasian College of Physicians, and the American College of Gastroenterology. Dr. McCallum has published more than 390 articles in peer-reviewed scientific journals, 100 textbook chapters, and has edited 13 scientific textbooks. The most recent textbooks that he has co-edited are entitled "GI Motility Testing – A Laboratory and Office Handbook," a reference text in this field and "Gastroparesis: Pathophysiology, Presentations, and Treatment." He serves on the editorial boards of eight scientific publications and committees of the major gastroenterology associations in this country. He was president of the Southern Society for Clinical Investigation, International Electrogastrogram Society, Trustee of the American College of Gastroenterology, and received the Southern Medical Association Award for Original Research. Pharmaceutically supported research is conducted by his research team and original research has been supported with VA Merit Reviewing funding, Pharmaceutical, American Diabetes Association, Foundation Grants, Small Business NIH Awards and most recently NIH Grant funding as part of the NIH Consortium in Gastroparesis.
Dr. McCallum's research has been focused on the physiology, pathophysiology, and pharmacology of gastrointestinal smooth muscle relating to disorders of motility and functional bowel disease involving the esophagus, stomach, small bowel, and colon. He has been continuously funded by the NIH, American Diabetes Association, and industry grants. He has made major advances in diagnosis and treatment of gastroparesis, especially in diabetes. As founding chair of medicine, he built a nationally competitive department of medicine at TTUHSC El Paso, as well as advancing research funding and starting fellowship programs. For the last 20 years his pioneering efforts in the area of electrophysiology of the gut and, specifically, electrical pacing of the stomach resulted in new therapeutic concepts for nausea and vomiting. Other research contributions that continue are in the recognition of cyclic vomiting as a major new etiology of nausea and vomiting in adults, diagnosing and treating dumping syndrome and rumination syndrome as well as other gut motility problems, such as anorectal motility disorders and irritable bowel and the spectrum of small bowel bacterial overgrowth. Developing new pharmacologic and medical device therapies for these entities are also ongoing projects..
Professor of Medicine
Associate Chairman for Research
Dr. Jerzy Sarosiek, in recognition of his innovative contributions to research in gastroenterology, has been bestowed with an honorary doctorate (Doctor honoris causa) from his alma mater, the Medical University of Bialystok in Bialystok, Poland. At the University of Virginia School of Medicine in Charlottesville, Virginia, in collaboration with Dr. Barry Marshall, M.D., 2005 winner of the Nobel Prize in Medicine, Dr. Sarosiek made great contributions to understanding the pathomechanism of development of gastric ulcers in patients infected by Helicobacter pylori.
Assistant Professor of Medicine
Director of Advanced Endoscopy
Dr. Mendoza-Ladd graduated cum laude from the University of San Carlos in Guatemala, in the 96th percentile of his class. He completed his internal medicine residency and general gastroenterology fellowship at Lenox Hill Hospital in New York, and subsequently obtained training in interventional endoscopy at Geisinger Medical Center in Pennsylvania. During his education and training, he obtained several distinctions, including University of San Carlos Catedra Prima excellence award, the NYU Robert M. Glickman award for excellence in research, the New York Society for Gastrointestinal Endoscopy video forum award, and the American Society for Gastrointestinal Endoscopy Crystal Award for colon cancer awareness outreach.
He is a member and fellow of the American Society for Gastrointestinal Endoscopy (ASGE) and the American College of Gastroenterology (ACG). He is also a member of the Texas Society for Gastrointestinal Endoscopy (TSGE) and the American Gastroenterological Association (AGA), where he serves as a member of the AGA Academy of Educators. He has served in numerous committees in all of these professional associations.
His clinical interests include endoscopic techniques and devices, biliary disorders, and particularly, management of acute and chronic pancreatitis. During his time at Texas Tech University Health Sciences Center El Paso, he has pioneered interventional endoscopy. Some of his achievements include performing the first EUS-directed transgastric ERCP and endoscopic full thickness resection of colonic lesions in Texas. He has published several original articles in peer-reviewed journals and is a key clinical faculty member of the TTUHSC El Paso gastroenterology fellowship program.
Areas of Interest:
- Pancreatobiliary diseases
- Endoscopic ultrasound (EUS)
- General gastrointestinal endoscopy
Gastroenterology Fellowship Program
Gastroenterology Research Coordinator
Certified Clinical Research Coordinator
Nancy Casner received her B.S. degree from Empire State College – S.U.N.Y and her M.S. degree in community health and health administration from Long Island University, N.Y. Nancy has been involved in research in the GI division since 1985, first as lab technician, doing bench research with Marc Zuckerman, M.D., and then as a clinical research coordinator in the GI and rheumatology divisions, since 1987. In 2000, Nancy received her certification from The Association of Clinical Research Professionals (ACRP). Nancy has conducted more than 70 clinical trials and has supervised many GI research coordinators. In addition to her clinical trial duties, Nancy is also currently working with the department of family and community medicine's ACCION program (Against Colon Cancer In Our Communities) which is funded by CPRIT.
To make an appointment please call:
IM Clinic: 915-215-5200