Dennis Oliver, M.D.
Internal Medicine
After graduating from Columbia University College of Physicians and Surgeons in New York, Dr. Oliver trained at a Columbia affiliate, St. Lukes-Roosevelt Hospital in Internal Medicine. He worked as a supervisory physician for Montefiore Medical Center in New York before and after voluntary service with the U.S. Air Force, and spent a great deal of time caring for patients with AIDS. His military career included a tour at Hellenikon Air Base in Athens, Greece. He moved to San Antonio in 1994 to practice with MacGregor Medical Association. He is board-certified by the American Board of Internal Medicine.
Grace Onuma, M.D
Family Practice
Dr. Onuma is a graduate of the University of Texas at Arlington. She obtained her medical degree from Ross University School of Medicine, and completed her medical residency in Family Medicine /Global Health at the University of Pittsburgh Medical Center, McKeesport. She later moved back to Texas (with similar weather to the one she grew up with in Nigeria), where she worked at a Federally Qualified Health Center (FQHC) in Bastrop Texas, prior to joining MacGregor.
Passionate about preventive health, chronic disease and obesity care, Dr. Onuma incorporates her years of experience working with underserved populations both in the US and abroad to care for her patients, bringing back humanity to the practice of medicine while helping patients achieve their health goals.
In her spare time, she loves spending time with friends and family or day dreaming about the next interior design project to take on. While some of those thoughts live on only in her imaginations, others eventually become reality.
Ana I. Rodriguez, M.D.
Internal Medicine
Dr. Rodriguez, a Puerto Rican native, graduated from the College of Human Medicine, Michigan State University in 1991. She moved to San Antonio Texas to finish her Internal Medicine Residency at the University of Texas Health Science Center in 1994, and remained as Instructor of Medicine and still works as Clinical Assistant Professor for UTHCSA since 1996. She joined MacGregor Medical Association, and then went on to help found MacGregor Medical Center of San Antonio in 2000. She loves teaching medical students at different years in their training, and is a member of the Texas Medical Association, Bexar County Medical Society and the American College of Physicians. Her hobbies include gardening, traveling and running.
Manuel Rodriguez, M.D
Internal Medicine
Dr. Rodriguez graduated in 1994 from Ponce School of Medicine where he was inducted into the Alpha Omega Alpha Honor Medical Society. He completed a residency in Internal Medicine at Washington University Medical Center in St. Louis, Missouri, and later became Board Certified in Internal Medicine. He moved to San Antonio in 1994 and became part of the MacGregor Medical family. He and his wife, a dentist, have three lovely children. Dr. Rodriguez has special interests managing diabetic, obese and hypertensive patients as well as patients with allergic rhinitis. He has been featured yearly as one of San Antonio’s best internists in San Antonio Magazine’s “Best Doctors”. Dr. Rodriguez is fluent in Spanish and speaks some French and Italian.
Carlos Roldan, M.D
Family Practice
The University of Antioquia Medical School in Medellin, Colombia granted an M.D. degree to Dr. Roldan. He spent a year in an Infectious Disease research fellowship, then completed a residency at Baylor College of Medicine in Houston, including a stint as a Chief Resident. He followed with a fellowship in Palliative Care at the University of Texas Health Science Center – San Antonio. He is board certified by the American Board of Family Practice, and practices family medicine as well as palliative care.
Jose Sanchez, M.D.
Internal Medicine
Dr. Sanchez graduated from Central del Caribe University School of Medicine in Puerto Rico. He completed a residency in Internal Medicine at the University of Texas Health Science Center here in San Antonio prior to joining MacGregor Medical Association in 1994. He played a leading role in the establishment of MacGregor Medical Center of San Antonio in 2000, and became its first President. He is board certified in internal medicine and also a clinical assistant professor of UT Health. Married with two lovely daughters, he is fluent in Spanish as well as English.
Brian Senger, M.D.
Internal Medicine
Dr. Senger was born and raised in St. Louis (which will be evident on your first visit.) He met his wife at Baylor University. He went to medical school at St. Louis University School of Medicine, then quickly returned to Texas for his residency in Internal Medicine at the University of Texas Health Science Center at San Antonio. He was appointed to a year as Chief Resident. In 2005 he received an appoinment as a Clinical Associate Professor at the Health Science Center.
Mark Smith, M.D.
Family Practice
Dr. Smith was born and raised in northwest Houston. Dr. Smith attended the University of Houston from 1976 to 1980, when he graduated summa cum laude with a BS in biology. During his undergraduate studies he researched and published a paper on intestinal hormones as part of his senior honors thesis. Mark attended the University of Texas Health Science Center at San Antonio Medical School from 1980 to 1984, and completed his Family Medicine Residency in 1987 at the University Hospital System in San Antonio. After residency, Dr. Smith went into private practice in north-central San Antonio from 1987 to 1995. He expanded into a group practice on the northeast side of San Antonio from 1996 to 2000, and in January of 2000 joined nine other physicians to found MacGregor Medical Center – San Antonio. Dr. Smith is board certified by the American Board of Family Medicine. He has two children – Jordan and Jeremy. Mark enjoys basketball, soccer, hockey and spending time with his family.
Rosa I. Vizcarra, M.D.
Family Practice
Dr. Vizcarra joined MacGregor in 2019 and we are so glad to have her! Originally from Mexico, she attended medical school at the Universidad Autonoma of Coahuila in Torreon, Coahuila, Mexico, then completed her medical training in Philadelphia, Pennsylvania. A residency in Family Medicine at Drexel University was followed by a fellowship in Geriatrics at Thomas Jefferson University.Dr. Vizcarra’s interest in education landed her a position with Texas Tech University Health Science Center Permian Basin Campus in Odessa, Texas. She started as an Assistant Professor, and directed a Family Medicine Residency program as well as a Geriatrics program, leading to an Associate Professor status before moving to San Antonio. In San Antonio, she began a solo practice and later joined a Palliative Medicine Program.Dr. Vizcarra loves primary and preventative care, with a passion for Geriatrics and addressing health disparities. She is an active member of the Texas Association of Family Medicine, The Texas Medical Association, and the American Geriatrics Society, and is a Fellow of the American Association of Family Medicine.Her favorite hobbies are reading, traveling, and running. She loves family gatherings and spending time with family and friends.
Juana Gaona FNP-C, DNP
Family Nurse Practitioner
Juana M. Gaona is a graduate from the University of Texas Health Science Center at San Antonio with her Doctorate in Nursing Practice.
She also earned her Master of Science in Nursing (MSN) in Nurse Practitioner and specialized in Family Practice. Upon graduation with her Family Nurse Practitioner (FNP),
she was inducted in Sigma Theta Tau International Honor Society and Golden Key Honor Society. She is nationally certified by the American Academy of Nurse Practitioners (AANP)
and holds a certification from the Texas Board of Nursing as a Advanced Practice Registered Nurse (APRN).
NP Gaona has practiced in various health care settings and has had the pleasure to have served rural and underserved patient populations of South Texas which included the entire age spectrum.
She brings a wealth of experience and training to MacGregor Medical Center. She has worked at long term care facilities, nursing homes, surgical and medical intensive care units as a charge nurse, post anesthesia care units, and pediatrics.
NP Gaona developed her love to assist in the healing of others at a very young age thus commencing her medical profession early in life. Her practice philosophy is based on culturally competent patient-centered care through a holistic approach.
In her free time, NP Gaona enjoys spending time with her family, she enjoys cycling, running and hiking.
Oscar Garcia, PA
Physician Assistant
Oscar Garcia is a Certified Physician Assistant who joins MacGregor Medical Group from P3 Health Partners in Las Vegas, Nevada where he provided primary care in family and internal medicine outpatient clinics.
Mr. Garcia’s determination and passion for medicine are a beautiful result of a trying experience as a combat medic in Iraq. During his several years and arduous overseas deployments, he found humor helped him to stay determined after long days. After checking off the adventure box, he left the Navy to pursue higher education with one goal in mind: to serve the community in which he lives.
He then went to New Mexico State University where he received his Bachelor’s degree in Biology and was awarded the Howard Hughes Scholarship. He was not done yet! Next up, he enrolled into the prestigious Duke University and was awarded the significant Underserved Community Scholarship and graduated from Duke with his Masters of Health Science and Physician Assistant certification.
He brings that vision, mission and passion for helping people with him to MacGregor Medical as a Certified Physician Assistant. Patients love his sense of humor and Oscar regularly uses laughter combined with experience and knowledge to provide excellent clinical service. He uses these tools to build mutual trust and long-term relationships with his patients.
Oscar walks-the-walk when it comes to how he advises patients for healthy living: stay active and eat healthy! (That means lifting weights, martial arts, running and making an effort to eat fresh/green foods in his spare time!) However, a self-proclaimed foodie, he savors finding new and exciting cuisine. He enjoys exploring San Antonio’s assortment of eclectic restaurants.