About Us
Since our founding in 2007, Texas Digestive Specialists (initially Gastroenterology Consultants of South Texas) has grown to be the premier digestive health practice serving South Texas, providing Gastroenterology, Colon and Rectal, and Advanced Weight Loss care.
We have a team of highly trained and dedicated healthcare professionals and staff, providing the highest level of care to every patient in a compassionate and timely manner.
Our Mission
Our goal is to restore and protect your digestive health so you can enjoy your life. We do this by accurately diagnosing and treating your current symptoms and helping to prevent future digestive health issues.
Adult Gastroenterology
NOLAN E. PEREZ, MD, FACP, FACG
Gastroenterology
Dr. Nolan Perez founded Texas Digestive Specialists (TDS), previously known as Gastroenterology Consultants of South Texas, in July of 2007.
Dr. Perez earned a Bachelor of Arts from the University of Texas at Austin and a Medical Doctorate from the University of Texas Health Science Center at San Antonio. After medical school, Dr. Perez served in the United States Navy as a Medical Corps Officer. He then completed residency training in Internal Medicine at the Regional Academic Health Center in Harlingen and fellowship training in Gastroenterology/Hepatology at Wayne State University/Detroit Medical Center. He is Board Certified in Gastroenterology and is a Fellow of the American College of Physicians and a Fellow of the American College of Gastroenterology. Dr. Perez is an active member of the American Gastroenterological Association (AGA), the American Society for Gastrointestinal Endoscopy (ASGE), the American Medical Association (AMA), the Texas Medical Association (TMA) and the Cameron/Willacy County Medical Society.
Dr. Perez currently serves as a member of the University of Texas System Board of Regents. He is also a Trustee for Harlingen CISD, member of the Philosophical Society of Texas and Governing Board for The Holdsworth Center. Dr. Perez is fluent in both English and Spanish. He is available for consultation in our McAllen, Harlingen and Brownsville offices.
NICOLE M. GRIGG-GUTIERREZ, MD
Gastroenterology
Dr. Nicole Grigg joined Texas Digestive Specialists (TDS) in November of 2017.
Dr. Grigg was born and raised in Puerto Rico. She earned a Bachelor of Science from the University of Puerto Rico and a Medical Doctorate from the Universidad Central del Caribe. She completed residency training in Internal Medicine and fellowship training in Gastroenterology, both at the Veteran Affairs Hospital in San Juan, Puerto Rico. She then completed an Advanced Endoscopy Fellowship at the Carolinas Healthcare System in Charlotte, North Carolina. She is Board Certified in Internal Medicine and Gastroenterology.
In 2016, Dr. Grigg moved to the Rio Grande Valley to practice Gastroenterology in Weslaco, TX. Dr. Grigg is an active member of the American Society of Gastrointestinal Endoscopy (ASGE) and American College of Gastroenterology (ACG). Dr. Grigg-Gutierrez is fluent in both English and Spanish. She is available for consultation in our McAllen, Harlingen and Brownsville offices.
SANDEEP T. SAMUEL, MD
Gastroenterology
Dr. Sandeep Samuel joined Texas Digestive Specialists (TDS) in June of 2018.
Dr. Samuel earned a Medical Doctorate from Kottayam Medical College and completed General Medicine Post-Graduate training at the Bangalore Medical College and Research Institute in India. He later completed residency training in Internal Medicine in 2014, and fellowship training in Gastroenterology in 2017 at the State University of New York (SUNY) in Buffalo, New York. He is Board Certified in Internal Medicine and Gastroenterology.
In 2017, Dr. Samuel moved to the Rio Grande Valley to practice Gastroenterology. Dr. Samuel is an active member of the American College of Gastroenterology (ACG), the American Society of Gastrointestinal Endoscopy (ASGE), American College of Physicians (ACP), Indian Medical Association (IMA) and the Association of Physicians of India (API). Dr. Samuel is available for consultation in our McAllen, Harlingen and Brownsville offices.
JASON R. PHILLIPS, MD, FASGE
Gastroenterology
Dr. Jason Phillips joined Texas Digestive Specialists (TDS) in October of 2019.
Dr. Phillips earned a Bachelor of Science in Physics from Abilene Christian University and a Medical Doctorate from the University of Texas Medical Branch in Galveston Texas. He completed residency training in Internal Medicine at the Mayo Graduate School of Medicine and fellowship training in Gastroenterology at the University of Michigan. He is Board Certified in Gastroenterology and a Fellow of the American Society of Gastrointestinal Endoscopy.
In 2006, Dr. Phillips founded Phillips Gastroenterology where he practiced for 12 years. In 2018, he became a Senior Staff Physician for Baylor Scott & White in Round Rock, Texas. Dr. Phillips is a reviewer for board questions and clinical relevancy for the American Board of Internal Medicine. He is a Clinical Assistant Professor for UTRGV School of Medicine. Dr. Phillips is available for consultation in our McAllen, Harlingen and Brownsville offices.
BRIAN P. RUTLEDGE, MD
Gastroenterology
Dr. Brian Rutledge joined Texas Digestive Specialists (TDS) in July of 2022.
Dr. Rutledge received his undergraduate and medical doctorate degrees from Wayne State University in Michigan, and completed his Internal Medicine residency and Gastroenterology fellowship training at Detroit Medical Center.
Dr. Rutledge’s professional interests include endoscopic procedures, gastrointestinal cancer prevention, treatment of gastroesophageal reflux disease, and long-term management of inflammatory bowel disease and chronic liver diseases. Dr. Rutledge speaks Spanish and English, and is available for consultation in our McAllen, Brownsville and Harlingen offices.
Juan J. Castano Jr., MD
Gastroenterology
Dr. Juan Castano joined Texas Digestive Specialists (TDS) in June of 2023.
Dr. Castaño has lived in the RGV for the last 7 years. He recently completed a gastroenterology (GI) fellowship at the University of Texas Rio Grande Valley (UTRGV) at Doctors Hospital at Renaissance (DHR) in Edinburg. He received a Bachelor of Science from the University of Houston, and Doctor of Medicine from the Universidad Autonoma de Guadalajara in Guadalajara, Jalisco, Mexico. He then completed Internal Medicine residency at UTRGV DHR in Edinburg. After residency and prior to his GI fellowship, he worked as an assistant professor of Internal Medicine at UTRGV teaching residents and medical students.
Dr. Castaño has lived in Texas his entire life. He was born in Dallas, but only lived there briefly before moving to Laredo where he attended elementary school. He was largely raised in Houston where he attended both middle school and high school. Dr. Castano is fluent in Spanish and English, and is available for consultation in our McAllen and Harlingen offices.
ALAN G. COATES, DO, FACOI
Gastroenterology
Dr. Alan Coates joined Texas Digestive Specialists (TDS) in February of 2019.
Dr. Coates earned a bachelor’s degree in biology from Western Michigan University and a Doctor of Osteopathic Medicine from the College of Osteopathic Medicine & Surgery in Des Moines, Iowa. He completed his internal Medicine Internship and Residency at Grand Rapids Osteopathic Hospital in Grand Rapids, Michigan and fellowship training in Gastroenterology from the University of Michigan Medical Center in Ann Arbor, Michigan. He is board certified in Internal Medicine and Gastroenterology.
He is the founder and CEO of Gastroenterology Associates of Western Michigan and of West Michigan Clinical Research Center (WMCRC). Through WMCRC, Dr. Coates has participated in several studies for gastroenterology conditions. Dr. Coates is an active member of the American Society for Gastrointestinal Endoscopy (ASGE), the American Osteopathic Association (AOA), Michigan Association of Osteopathic Physicians and Surgeons, as well as a Fellow of the American College of Osteopathic Internal Medicine. Dr. Coates speaks Spanish and English and is available for consultation in our Brownsville and Harlingen offices.
Oscar A. Alvarez, MD
Gastroenterology
Dr. Oscar Alvarez Joined Texas Digestive Specialists (TDS) in July of 2022.
Dr. Alvarez received his physician and surgeon degree and completed residency at the Instituto Ciencias de la Salud (CES). He moved to the US in 1988 and completed internal medicine residency at UT Health Science Center in San Antonio (UTHSCSA). He also completed a fellowship in gastroenterology and nutrition, and a fellowship in advanced endoscopy at UTHSCSA. During this time, he created a medical student visiting program for students from CES University in Colombia to visit UTHSCSA, and this program is still thriving today.
Dr. Alvarez is the former Chairman of the GI and Endoscopy Division at the VA clinic in Harlingen. Prior to that he was a gastroenterologist in private practice in McAllen for 10 years. He was previously a Clinical Assistant Professor at UTHSCSA and serves as an Assistant Professor at the Instituto Ciencias de la Salud (CES) in Medellin, Colombia.
Dr. Alvarez is a member of the American College of Gastroenterology, and he has published numerous abstracts and articles in peer reviewed medical journals. He has received many honors and awards over his career, including being named a Commendable Alumnus of CES Universidad and a Special Honorary Member of the Medellin Academy of Medicine. Dr. Alvarez is fluent in Spanish and English, and is available for consultation in our McAllen and Harlingen offices.
OWEN S. MAAT, MD
Gastroenterology
Dr. Owen Maat joined Texas Digestive Specialist (TDS) in November of 2023.
Dr. Maat completed a Gastroenterology and Hepatology Fellowship at the University of Texas MD Anderson Cancer Center and Internal Medicine residency at The University of Texas Health Science Center in Houston. He received his medical degree from the University of Texas Medical Branch at Galveston. Dr. Maat brings more than 30 years of clinical experience to the RGV from his time in Louisiana, Arkansas and Texas.
Dr. Maat is a Fellow of the American College of Gastroenterology (ACG). He is board certified in gastroenterology and specializes in digestive care, hepatology and nutrition with extensive experience and skills in general and advanced endoscopic procedures. He is available for consultation in our Harlingen and Brownsville offices.
ANTHONY GALAN, MD
Gastroenterology
Dr. Anthony Galan joined Texas Digestive Specialists (TDS) in December of 2023.
Dr. Galan was born in Puerto Rico and raised in the Dominican Republic. He earned his Medical Doctorate from UNPHU School of Medicine in Santo Domingo. Following that, he completed residency training in Internal Medicine at the Graduate Hospital in affiliation with The University of Pennsylvania. He further specialized in Gastroenterology through a Fellowship Allegheny University Hospitals in Philadelphia, PA, where he trained with nationally and internationally recognized clinicians in the field.
He is a member of several esteemed professional organizations including the American Gastroenterology (AGA), American College of Gastroenterology (ACG), American Society for Gastrointestinal Endoscopy (ASGE) and Bockus International Society of Gastroenterology.
Dr. Galan has more than 20 years of experience and he specializes in digestive care, hepatology, and nutrition. He has extensive and skills in experience in general and advanced endoscopic procedures. Dr. Galan has primarily practiced in Laredo, Tx and is thrilled to return to the RGV. Dr. Galan is fluent in both English and Spanish and is available for consultations in our Harlingen and Brownsville offices.
Mauro Silva, MD
Gastroenterology
Dr. Mauro Silva joined Texas Digestive Specialists (TDS) in August 2024. Born and raised in El Paso, he brings a wealth of knowledge and skills to the RGV. Dr. Silva earned his Bachelor’s degree from The University of Texas at Austin, Masters degree in Public Health from UT Health Science Center in Houston, and received his Medical Doctorate from McGovern Medical School in Houston. Dr. Silva completed Internal Medicine residency training at UT Southwestern Medical Center in Dallas, and he recently completed fellowship training in Gastroenterology and Hepatology at the University of Texas Medical Branch in Galveston.
Dr. Silva is fluent in English and Spanish and is available for consultations in our Harlingen and Brownsville offices.
Ingrid Chacon, MD
Gastroenterology
Dr. Chacon is board-certified in Gastroenterology, Internal Medicine and the Obesity Medicine. She completed her internal medicine residency training at New York Medical College and fellowship training in gastroenterology at the University of Arkansas for Medical Sciences.
She previously held multiple academic positions including Assistant Professor at the University of Texas Rio Grande Valley (UTRGV) School of Medicine. She has received multiple awards for academic excellence and has presented her research findings at major medical conferences.
Dr. Chacon has called McAllen home for the last 19 years with extensive gastroenterology clinical experience serving the RGV in outpatient and inpatient settings.
MARIBEL M. DE PONCE, PA-C
Gastroenterology
Maribel De Ponce joined Texas Digestive Specialists (TDS) in July of 2011.
She obatained her bachelor’s and master’s degree in physician assistant studies at the University of Texas Pan American in Edinburg. She is board certified and has accumulated extensive knowledge and experience in Gastroenterology. Previously, she worked in Orthopedics from 2009-2011. Maribel is an active member of the Texas Academy of Physician Assistants and American Academy of Physician Assistants. She is fluent in English and Spanish and is available for consultation in our Harlingen office.
STEPHANY SOSA, FNP
Gastroenterology
Stephany Sosa joined Texas Digestive Specialists (TDS) in April of 2018.
She grew up in Brownsville, Texas and received a Bachelor of Science in Nursing in 2012 from the University of Texas at Arlington and a Master of Science in Nursing also from the University of Texas at Arlington in 2017. She has been a Certified Family Nurse Practitioner since 2018. She is a Basic Life Support and Advanced Cardiovascular Life Support instructor for the American Heart Association.
Stephany previously worked at Valley Regional Medical Center as an Intensive Care Unit Nurse and as a Nationally Certified/ EMT-Paramedic as well as an International Trauma Life Support Advanced Provider. Stephany is an active member of the Critical Care Nurse Association, the National Nurses United Organization, and the American Nurses Association. She is fluent in English and Spanish and is available for consultation in our Brownsville office.
MICHELLE LOPEZ, FNP
Gastroenterology
Michelle Lopez joined Texas Digestive Specialists (TDS) in August of 2018.
She received her Bachelor of Science in Nursing from the University of Texas at Brownsville. She later graduated from the University of Texas Rio Grande Valley with her Master of Science in Nursing- Family Nurse Practitioner. Michelle is a member of the American Nurses Association and a Texas Nurse Practitioners. She is fluent in English and Spanish and is available for consultation in our Harlingen office.
MIRIAM DE LEON, PA-C
Gastroenterology
Miriam De Leon joined Texas Digestive Specialists (TDS) in April of 2019.
She obtained her Bachelor of Science in Biomedical Sciences from the University of Texas Rio Grande Valley, and later obtained a Master of Physician Assistant Studies from the same institution. She is fluent in English and Spanish and is available for consultation in our Brownsville and Harlingen offices.
ANA C. AGUAYO, PA-C
Gastroenterology
Ana Aguayo joined Texas Digestive Specialists (TDS) in April of 2021.
She earned her Bachelor of Science in Clinical Laboratory Sciences from the University of Texas Rio Grande Valley, graduating Summa Cum Laude. Subsequently, she pursued her Master of Science in Physician Assistant Studies at the University of Texas Rio Grande Valley. She is currently an active member of the Texas Academy of Physician Assistants. She is fluent in English and Spanish and is available for consultation in our McAllen and Harlingen offices.
DANIELA RIVAS, FNP
Gastroenterology
Daniela Rivas joined Texas Digestive Specialists (TDS) in August of 2019.
She obtained her Bachelor of Science in Nursing from the University of Texas at Brownsville. She further pursued her Master of Science in Nursing degree at Chamberlain University. Daniela is a member of the American Association of Nurse Practitioners and the American Nurse Association. She is fluent in English and Spanish and is in charge of our inpatient services in Harlingen and Brownsville.
LISA BRIONES, PA-C
Gastroenterology
Lisa Briones joined Texas Digestive Specialists (TDS) in April 2022.
She received her Bachelor of Science degree from the University of Texas at Brownsville. She went on to pursue a Master of Science in Health Informatics degree from the University of Texas Health Science Center in Houston. Lisa returned to the valley where she obtained her Master of Science in Physician Assistant Studies from University of Texas Rio Grande Valley. Lisa is a member of the American Academy of Physician Assistants and Texas Academy of Physician Assistants. She is fluent in English and Spanish and is available for consultation in our Brownsville office.
NADIA LOZANO, FNP-C
Gastroenterology
Nadia Lozano joined Texas Digestive Specialist (TDS) in August of 2022.
Nadia holds a Bachelor of Science in Nursing degree from Texas A&M University and a Master of Science in Nursing degree from Simmons University. Currently, she is pursuing her Doctor of Nursing practice degree at Simmons University. Nadia is a board-certified Nurse Practitioner through the American Academy of Nurse Practitioners. She is fluent in English and Spanish and is available for consultation in our Harlingen office.
Saraceli M. Salas-PA-C
Gastroenterology
Saraceli joined Texas Digestive Specialists (TDS) in June of 2023.
Saraceli earned a Bachelor of Science in Biomedical Sciences from the University of Texas Rio Grande Valley (UTRGV) and a Master of Science in Healthcare Administration in 2019 from the same university. In 2022, She obtained a master’s in physician assistant studies from UTRGV. She is fluent in English and Spanish and is available for consultation in our Brownsville and Harlingen offices.
Angel Amaya, FNP
Gastroenterology
Angel joined Texas Digestive Specialists (TDS) in February 2024. He received an Associate degree in Nursing from the University of Texas at Brownsville in 2013, followed by a Bachelor of Science in Nursing from Grand Canyon University in 2015, and a Master of Science in Nursing from Chamberlain University in 2020. Angel brings over 10 years of clinical experience. He is fluent in Spanish and English and oversees our inpatient services in Hidalgo County.
Lisa Lopez, FNP
Gastroenterology
Lisa Lopez joined Texas Digestive Specialist (TDS) in July 2024.
She earned her Bachelor of Science in Nursing and a Master of Science in Nursing, both from the University of Texas Rio Grande Valley. She brings over 10 years of clinical experience. Lisa is an esteemed member of American Nurse Association, Texas Nurse Association, and Texas Nurse Practitioner Association. She is available to see patients in our Brownsville and Harlingen offices.
Mayra P. Rendon, FNP
Gastroenterology
Mayra P. Rendon joined Texas Digestive Specialist (TDS) in July 2024.
She earned a Master of Science in Nursing in Family Nurse Practitioner from the University of Texas at Arlington. Prior to that, she obtained a Bachelor of Science in Nursing from Texas A&M University in Corpus Christi. Mayra is part of our inpatient hospital team in Harlingen and Brownsville, and she is fluent in Spanish and English.
Pediatric GASTROENTEROLOGY
MIHAELA RINGHEANU, MD
Pediatric Gastroenterology
Dr. Ringheanu joined Texas Digestive Specialists (TDS) in July of 2019.
Born and raised in Romania, she earned a Medical Doctorate from Universitatea De Medicina Si Farmacie in Burcharest. She completed her Pediatric Residency at Maimonides Medical Center in New York, NY and fellowship training in Pediatric Gastroenterology at North Shore University Hospital in Manhasset, NY. Dr. Ringheanu is Board Certified in Pediatrics and Pediatric Gastroenterology.
In 2003, Dr. Ringheanu moved to the Rio Grande Valley to join Harlingen Physician Network in Harlingen, TX. In 2008, she founded GI Care for Kids. Dr. Ringheanu has been a Member of the American Academy of Pediatrics since 1997. She is a member of the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition and a Clinical Assistant Professor for UTRGV School of Medicine.
Dr. Ringheanu is fluent in English and Spanish and is available for consultation in our Harlingen and McAllen offices.
JESUS MEDINA, PA-C
Pediatric Gastroenterology
Jesus joined Texas Digestive Specialists (TDS) in March of 2022.
He received his Bachelor of Science in Biology degree from the University of Texas at Brownsville and obtained his Master of Science in Physician Assistant Studies from University of Texas at Rio Grande Valley in 2019. Jesus is a board-certified Physician Assistant through the National Commission on Certification of Physician Assistants. He is fluent in English and Spanish and is available for consultation in our Harlingen office.
ERIKA TIDWELL, FNP
Pediatric Gastroenterology
Erika joined Texas Digestive Specialists (TDS) in May of 2023.
She obtained a Bachelor of Science in Nursing from the University of Texas at Arlington, graduating Magna Cum Laude. Erika then pursued a Master of Science in Nursing-Family Nursing Practice. Currently, she is pursuing a Doctor of Nursing Practice degree at the University of Texas of the Rio Grande Valley. Erika is a member of the American Psychiatric Nurses Association and the American Association of Nurse Practitioners. She is fluent in English and Spanish and is available for consultation in our Harlingen and McAllen offices.
ColoN & rectal Surgery
ALBERTO PEÑA, MD, FACS, FASCRS
Colon & Rectal Surgery
Dr. Alberto Peña joined Texas Digestive Specialists (TDS) in January 2022. Board-certified in colon and rectal surgery, he brings over 13 years of experience to his practice. Specializing in the diagnosis and treatment of disorders affecting the colon, rectum, and anus, Dr. Peña utilizes minimally invasive and robotic surgical procedures. Additionally, he performs diagnostic colonoscopies, anorectal physiology assessments, and provides treatment for fecal incontinence.
Dr. Peña received his medical degree from University of Texas Health Science Center at San Antonio. He completed residency training in general surgery at Methodist Health System in Dallas, TX., and colon and rectal surgery fellowship training at the University of Southern California. He’s available to see patients in McAllen, Harlingen and Brownsville.
DUSTIN LUEBBERS, MD
Colon & Rectal Surgery
Dr. Dustin Luebbers joined Texas Digestive Specialists (TDS) in June 2022. He is Board-Certified in colon and rectal surgery, with a focus on minimally invasive and robotic surgical treatments for various conditions. His expertise includes addressing cancers of the colon, rectum, and anus, as well as managing hemorrhoids, anal fissures, fistulas, diverticulitis, Crohn’s disease, ulcerative colitis, rectal prolapse, pilonidal cysts, anal condyloma, and fecal incontinence.
Dr. Luebbers earned his medical degree at the American University of the Caribbean. He completed a general surgery residency at the University of Texas Rio Grande Valley and a fellowship in colon and rectal surgery at Brown University. He’s available to see patients in McAllen, Harlingen and Brownsville.
Haiser E. Dao, MD, FACS, FASCRS
Colon & Rectal Surgery
Dr. Dao received his medical degree from University of Carabobo, in Valencia Venezuela. After a year-long internship in an undeserved area, he started General Surgery residency at Hospital Miguel Perez Carreno, one of the busiest academic canters in Caracas. He then relocated to the Unites States and joined St. Elizabeth’s Medical Center in Boston, where he completed General Surgery residency, followed by a fellowship in Colon and Rectal surgery at Brown University in Providence, RI.
After his training, Dr. Dao worked as a colorectal surgeon at St. Elizabeth’s Medical Center until 2016. He then joined the University of Texas Health San Antonio (UTHSCSA) where he worked for the next 8 years and achieved Associate Professor of Surgery. Dr. Dao is available for consultation in McAllen, Harlingen, and Brownsville.
VERONICA MESQUITIC, FNP
Colon & Rectal Surgery
Veronica joined Texas Digestive Specialists in December 2021. She received her Bachelor of Science from the College of Nursing at Grand Canyon University in Phoenix and pursued her Master of Science Nurse Practitioner degree from University of Texas at El Paso in 2018. Veronica is certified in Ostomy care. Prior to joining our practice, she worked at DHR as a PACU nurse from 2005-2019 and as a Nurse Practitioner from 2019-2021. Veronica is available to see patients in our McAllen office.
ADRIANA NASH, FNP
Colon & Rectal Surgery
Adriana joined Texas Digestive Specialists in September 2022. She brings 6 years of experience as a Family Nurse Practitioner and over 17 years of overall clinical experience. She completed her Master of Science in Nursing in Family Nurse Practitioner from Maryville University in St. Louis, Missouri, after receiving her Bachelor of Science in nursing from the University of Texas at Brownsville and Texas Southmost College. Adriana is a member of the American Academy of Nurse Practitioners and has prior experience in pediatrics and labor and delivery. She is available to evaluate and treat patients at our Brownsville and Harlingen offices.
METABOLIC AND FOREGUT SURGERY
MICHAEL J. MARTINEZ, MD
Bariatric & Foregut Surgery
Dr. Michael J. Martinez is a native of the Rio Grande Valley. He joined Texas Digestive Specialists (TDS) in February 2022. Dr. Martinez completed undergraduate studies at Princeton University and earned his medical degree from Yale School of Medicine. Dr. Martinez returned to Texas to complete general surgery training at Baylor Scott and White, and then completed specialty training in the area of minimally invasive and bariatric surgery at the University of South Florida at Tampa General Hospital. He is Board Certified by the American College of Surgeons and is a Fellow of the American College of Surgeons and the American Society of Metabolic and Bariatric Surgeons. Dr. Martinez is an advanced minimally invasive weight loss surgeon using robotic, laparoscopic, and endoscopic techniques for the treatment of his patients. He is also an accomplished foregut surgeon specializing in Gastro-Esophageal Reflux Disease (GERD), gastroparesis and achalasia. He is fluent in English and Spanish, and is available to consult with patients in our Brownsville and McAllen locations.
JESUS GARCIA, MD
Bariatric & Foregut Surgery
Dr. Jesus Garcia completed his Foregut and Bariatric Surgery Fellowship at Louisiana State University under world renowned faculty and surgeons. Prior to that, he completed general surgery residency at the University of Texas Rio Grande Valley at DHR in Edinburg. He and his family are proud to be back home in the Rio Grande Valley.
Dr. Garcia was born in La Mirada, California, located in LA county. His family later moved to Toluca, Mexico where he was raised. He was exposed to the medical field early on by his father, who worked as a chemist for the national health system in Mexico. In pursuit of better opportunities, Jesus and his family immigrated to Kansas City, Kansas. He completed high school and attended college at Kansas State University, graduating with a Bachelor of Science in microbiology. He then received a master’s degree from Saint Louis University in Human Anatomy and Physiology, followed by a medical degree at the University of Kansas School of Medicine. Dr. Garcia is fluent in English and Spanish, and is available to consult with patients in our Brownsville and McAllen locations.
MATHEW B. MARTINEZ, PA-C
Bariatric & Foregut Surgery
Mathew joined Texas Digestive Specialists (TDS) in April 2022. He completed his Physician Assistant master’s degree in 2014 from the University of Texas at Rio Grande Valley. He holds a Doctor of Medicine degree from Baylor College Medicine and a bachelor’s in biology from Texas A&M University. With prior experience in orthopedics, Mathew is a member if the Texas Academy of Physician Assistants and the American Academy of Physician Assistants. He is fluent in English and Spanish, and is available to evaluate patients in our Brownsville and McAllen Locations.
LUIS G. VILLEGAS, PA-C
Bariatric & Foregut Surgery
Luis Villegas joined Texas Digestive Specialists in February 2023. He was born and raised in the Rio Grande Valley and completed his Master of Physician Assistant Studies from The University of Texas Rio Grande Valley (UTRGV). He also obtained his Bachelor of Science degree in Biomedical Sciences from UTRGV. Additionally, Luis is a member of the American Academy of Physician Associates and the Texas Academy of Physician Assistants. He is fluent in English and Spanish, and is available to evaluate patients in our Brownsville and McAllen Locations.
Mirsa Garcia, DNP, APRN, FNP-C
Bariatric & Foregut Surgery
Mirsa joined Texas Digestive Specialist (TDS) in June 2024. She completed her Doctor of Nursing Practice in May 2024 from the University of Texas at Rio Grande Valley. In 2020, she graduated with her Master of Science in Nursing from the University of Texas at Arlington. Mirsa earned a Bachelor of Science in Nursing in 2017 from the University of Texas at Rio Grande Valley. Prior to that, she became a Licensed Vocational Nurse (LVN) and received an Associate of Science in Nursing, both from South Texas College. Mirsa is fluent in Spanish and English and is available for consultation in our McAllen and Brownsville offices.
Department of Pathology
William Neumann, MD
Pathology
Dr. William Neumann joined Texas Digestive Specialists in August 2023.
He brings over 10 years of experience in anatomical and clinical pathology and 8 years of experience as a Laboratory Medical Director.
Dr. Neumann graduated from the University of Texas at Austin before earning his medical doctorate at the University of Texas Health Science in San Antonio. He subsequently completed an Anatomic and Clinical Pathology residency at Baylor Scott & White in Temple, Texas followed by Surgical Pathology and Gastrointestinal Pathology fellowships at the University of Texas Southwestern Medical Center in Dallas.
Dr. Neumann is board certified in both Anatomic and Clinical Pathology and is a member of the College of American Pathologists and the Hidalgo-Starr Medical society. Dr. Neumann’s passion lies in histologic examination of biopsies so that he can provide accurate diagnoses to his physicians and optimize patient care.
Qinghua Yang, MD, PhD
Pathology
Dr. Qinghua Yang joined Texas Digestive Specialists in September 2023. He brings over 20 years of experience as a board-certified Anatomical and Clinical Pathologist.
Dr. Yang completed his pathology residency training at the University of Kansas Medical Center and pursued subspecialty fellowship training in Gastrointestinal (GI) Oncologic Pathology at the University of Texas MD Anderson Cancer Center in Houston, TX. He is a member of the College of American Pathology and the American Gastroenterological Association. Dr. Yang has contributed to the field with numerous research papers published in peer-reviewed journals and presentations at national and international meetings.
Before embarking on his pathology career, Dr. Yang served as a GI post-doctoral research fellow at the University of Michigan, Ann Arbor, and the University of California, San Diego. Prior to relocating to the United States, he practiced as a gastroenterologist in Shanghai, China.
