Thet H Aung, M.D
Internal Medicine
Dr. Aung received his undergraduate degree (BSc) majoring in chemistry and physiology from the University of Alberta, Canada. He then completed his studies in medicine at UNIBE in the Dominican Republic where he graduated as Doctor of Medicine with magna cum laude. He went on to train for his post-graduate studies at Good Samaritan Internal Medicine residency program in Cincinnati, Ohio from 2006 to 2009. Both during his undergraduate and in his post-graduate years, he was actively involved in community services such as the Ecology group in UNIBE and serving as a medical volunteer in a medical mission to Honduras as part of the Holy Savior group. He achieved board certification in Internal medicine upon graduation from Internal Medicine residency in 2009.
After his formal training, Dr. Aung went on to join a large multi-specialty group in an underserved area of central New Hampshire from 2009 to 2013 practicing traditional Internal medicine/Primary care in both inpatient and outpatient settings. He moved to Texas in 2013 with his family to pursue a career in the care of the elderly in Medicare Advantage population for a year before being admitted to a fellowship training in Geriatrics Medicine at UT health Science center in 2014. He became Board certified in Geriatrics Medicine in 2015. He then spent the next six years of his career in Wellmed from 2015 until 2022 also in the care of the elderly Medicare population.
On his spare time, he loves to travel the world with his family visiting historic sites and picking up new languages. He also likes the outdoors including hiking and camping. His favorite sports and hobbies include Swimming, Aikido, Jujitsu and firearms training amongst others.
He is an avid student of medical economics and innovative healthcare delivery models exploring alternate ways of making healthcare more cost effective while optimizing quality and improving provider satisfaction at the same time. He also precepts for Nurse practitioner students, medical students and Internal medicine residents with UT medical school. He is fluent in English, Spanish and Burmese.
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.
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.
Ranjani Amin, DO
Dr. Ranjani Amin obtained her medical degree from Touro University in Nevada before completing her family medicine residency at Broward Health Medical Center in Ft. Lauderdale, Florida. She then moved back to her home state of Texas as an attending at Baylor College of Medicine followed by a short stint at Village MD prior to joining Macgregor in 2022.
Dr. Amin grew up in San Antonio and was a patient at Macgregor starting in high school before gaining her Bachelor of Science in Biology at the University of Texas at Austin. It was that patient experience that inspired her to pursue medicine. She was moved by the care she received and wanted to pay it forward as a provider and has since focused on preventative medicine and women’s health.
In her free time, she loves spending time with her family, traveling and baking sweet treats. She is fluent in Telugu and can understand Kannada.
Jeremy Diaz, PA-C
Physician Assistant
PA Jeremy Diaz joined MacGregor in 2020 after practicing Primary Care Medicine from San Antonio to the southernmost Rio Grande Valley, Texas regions. Since 2006 Jeremy has worked to empower patients in understanding treatment and preventative care options for healthful living from his years as a Nursing Aid, Medical scribe, and Medical research. His patient philosophy is building trust for long-term relationships, bringing multicultural competence with moderate Spanish language fluency having been raised on the Texas-Mexico border among underserved, indigent, and undocumented populations. PA Diaz completed his Master of Science in Physician Assistant Studies from UT Rio Grande Valley 2017 with a thesis on Acute Anxiety and Bachelor of Science from UTSA Honors College in Biology. Jeremy is board certified by the National Commission on the Certification of Physician Assistants (NCCPA) Board and has earned certifications in Advanced Cardiac Life Support (ACLS) and Basic Life Support (BLS). PA Diaz loves exploring the Hill Country with his wife and supporting local San Antonio coffee shops where you’ll see him doting on his Boston terrier while sipping Cold Brew Coffee. In his spare time, he can also be found making and delivering home-made Mexican meals for Veteran and Homeless residents in South Texas.
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-C
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.
Sabrina Sanchez, PA-C
Physician Assistant
PA Sabrina Sanchez was born and raised here in San Antonio, Texas. She has always had a passion for expanding access to healthcare, and she is very thrilled to be a part of the MacGregor team to help serve her home community.
PA Sanchez received her Master of Physician Assistant Studies from Hardin Simmons University in Abilene, where she was awarded Best Overall PA Student. She also received her Bachelor of Biomedical Sciences from Texas A&M University in College Station. Sabrina is board-certified by the National Commission on Certification of Physician Assistants (NCCPA).
In her free time, she loves to travel, watch Aggie football, attend Spurs games, do puzzles, and spend time with friends and family.