Dr. Prosser originally hails from Cheyenne, Wyoming. After receiving his degree in biology from Creighton University in Omaha, NE, he completed medical school at the University of Colorado. It was also in Denver that he had the fortune of meeting his wife, Dana. He then completed his Internal Medicine residency in Charlotte, NC at the Carolinas Medical Center before moving on to Baltimore, MD to finish his training with a Gastroenterology Fellowship through the Johns Hopkins Hospital. He and Dana then moved directly to Grand Junction in 2007 where they have been proud to raise two sons and call the Grand Valley home
Dr Shields is a native of Colorado. He attended Western State Colorado University with a degree in biology followed by medical school at Kansas City University of Medicine and Biosciences. He completed Internal Medicine Residency and Gastroenterology Fellowship at the Naval Medical Center in San Diego, CA and Hepatology training at the Scripps Clinic in La Jolla, CA. He stayed on faculty at the Naval Medical Center and was an Assistant Professor of Medicine at the Uniformed Services University of Health Sciences for five years before joining Grand Junction Gastroenterology in 2014. He is board certified in Gastroenterology. He is a Fellow of the American College of Physicians and American College of Gastroenterology.
Dr. Winters graduated from Cornell University and the University of Vermont, College of Medicine. He completed his Internal Medicine residency at Fitzsimons Army Medical Center in Aurora, Colorado and completed his Gastroenterology Fellowship at Walter Reed Army Medical Center in Washington, DC. He spent five years overseas as the Chief of Gastroenterology at Landstuhl Regional Medical Center in Germany and practiced nine years in Seattle, Washington prior to moving to Grand Junction in July, 2015. He is board certified in Gastroenterology. He is a member of the American Society of Gastrointestinal Endoscopy. He is a Fellow of the American College of Physicians and the American College of Gastroenterology
Dr. Sarges has a passion for caring for people with gastrointestinal system disorders. He’s experienced in capsule endoscopy, fecal transplant, inflammatory bowel disease, and colon cancer screening. He earned his medical degree from Tufts University School of Medicine in Boston, Mass. He continued on to complete his residency and fellowship at Georgetown University Hospital. Dr. Sarges served as both a chief fellow and a chief resident at Georgetown Hospital. Prior to relocating to Grand Junction in the summer of 2019 he worked at a medical practice on the Front Range of Colorado. Dr. Sarges is board certified in gastroenterology and internal medicine.
Dr. Dy graduated from Indiana University School of Medicine and completed her Internal Medicine Residency at the Indiana University Medical Center. She completed her Gastroenterology Fellowship at the University of Texas Medical Branch in Galveston, Texas where she was Chief Fellow. She did an Advanced Therapeutic Endoscopy Fellowship at Allegheny General Hospital in Pittsburgh, PA. She practiced 21 years in Des Moines, Iowa before moving to Glenwood Springs, Colorado where she worked prior to joining Grand Junction Gastroenterology in 2022. She is Board Certified in Gastroenterology and is a member of the American College of Gastroenterology, the American Society of Gastrointestinal Endoscopy and the American Gastroenterological Association.
Dr. Dan Castresana, M.D., who is relocating with his wife and two daughters from Georgia, is a very skilled gastroenterologist who is not only highly adept at standard upper and lower endoscopies but is also a fellowship-trained advanced therapeutic endoscopist who brings a unique skill set to the Grand Valley in order to meet a large, unmet demand. Having completed training and holding associate professor titles at New Mexico and Oregon after completing medical school at the Medical College of Georgia, he will perform endoscopic ultrasound (EUS), advanced therapeutic ERCP, and can also employ state-of-the-art techniques of endoscopic mucosal resection for the management of a variety of malignant and premalignant pathologies. This will allow our practice to now provide gastroenterology care locally that was once only available in major metro areas.
Dr. Michael Harris, D.O. has just completed his training in all aspects of gastroenterology and hepatology care, including ERCP, at Parkview Medical Center in Pueblo. Originally from Missouri and completing medical school at Kansas City University of Medicine & Biosciences, he completed both his internal medicine residency and gastroenterology fellowship in Pueblo. Recently married, both he and his wife have fallen in love with Colorado and look forward to making Grand Junction home. He will be available to provide all facets of GI care to help meet the rising needs of our community.