Nephrology is the study of the function and diseases of the kidneys. Our nephrologists are specially trained to take care of transplant patients.

Charles R. Nolan, MD
Professor of Medicine and Surgery
The UT Health Science Center at San Antonio

Dr. Nolan is the Medical Director of the kidney and pancreas transplant program at University Hospital. He received his undergraduate and medical degrees from the University of Colorado. He completed his Internal Medicine residency training at Wilford Hall Medical Center, Lackland Air Force Base, Texas. He completed his fellowship in Nephrology at the University of Colorado in Denver. Dr. Nolan served as the chief of the Nephrology division at Wilford Hall Medical Center before joining the faculty at The UT Health Science Center in 1992. Dr. Nolan is responsible for the evaluation of patients who are candidates for kidney and pancreas transplant. He also manages the long-term care of kidney and pancreas transplant patients. Dr. Nolan has an active research laboratory involved in studying mechanisms of kidney transplant rejection with research grant funding from the Veterans Administration. Dr. Nolan is the principal investigator for numerous clinical research studies in the areas of kidney transplant, renal dialysis and hypertension (high blood pressure).

Daniel J. Riley, MD
Associate Professor of Medicine
The UT Health Science Center at San Antonio

Dr. Daniel Riley received his medical degree at S.U.N.Y. Health Science Center at Syracuse. He completed his internship and residency at Case Western Reserve University/University Hospitals of Cleveland, Cleveland, Ohio and a fellowship in Nephrology at The UT Health Science Center at San Antonio. In addition to running an active research laboratory, he assists in the pre- and post-operative care of kidney and pancreas transplant patients.

Christine M. Toth, MD
Renal Associates, PA
Adjunct Associate Professor
The UT Health Science Center at San Antonio

Dr. Toth maintains board certification of Internal Medicine as well as Nephrology.  Her medical studies were completed at Hahnemann University School of Medicine. She performed her Nephrology Fellowship at Wilford Hall Medical Center in San Antonio, Texas and Transplantation Fellowship at Massachusetts General Hospital in Boston, Massachusetts. In addition to serving patients in the San Antonio area, Dr. Toth has served the USA via the United States Air Force.  She has been with Renal Associates since 2001. While she loves all of her patients, there is a special place in Dr. Toth’s heart for transplantation.

Jessica L. Pierce, MD, PhD
Renal Associates, PA
Adjunct Assistant Professor
The UT Health Science Center at San Antonio

Dr. Pierce received her medical degree and doctorate of philosophy from the University of Texas Health Science Center at San Antonio. She completed both an Internal Medicine residency and a Nephrology fellowship at University Hospital in San Antonio, Texas.

V. Herman Villarreal, MD
Renal Associates, PA
Adjunct Assistant Professor
The UT Health Science Center at San Antonio

Dr. Villarreal studied medicine at The National University of Mexico in Mexico City.  After receiving his medical degree he completed his post-graduate training at Northwestern University in Chicago, Illinois, Washington University, Barnes Hospital in St. Louis, Missouri, Rockefeller University in New York City and Southwestern University in Dallas, Texas.  Dr. Villarreal has been a member of multiple societies including the American Society of Transplant Physicians, American Society of Nephrology and the Harvey Society.  Dr. Villarreal has published several research papers on kidney disease and is co-editor of two books on clinical immunology of the heart and kidney.  Dr. Villarreal is board certified in Nephrology.