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Mihaela Perijoc, MD, MHA, is an eminent board-certified internal medicine physician and functional medicine specialist providing exceptional health care for patients at North Texas Internal Medicine Specialists in Plano, Texas. Dr. Perijoc has outstanding medical skills that she combines with a passion for providing the highest standard of care for her patients.

Dr. Perijoc began her career by obtaining her medical degree from the Institute of Medicine and Pharmacy (Carol Davila), Bucharest, Romania. After qualifying as a doctor, she undertook her residency in internal medicine at St. Vincent Indianapolis in Indiana. Dr. Perijoc remained at St. Vincent to complete a procedural fellowship in internal medicine.

Dr. Perijoc went on to gain valuable experience in high-profile positions at hospitals and health care institutions across Texas, honing her already considerable skills and becoming a leading advocate for raising quality standards. She developed a new model of patient care that emphasizes continuity of care and places the patient at the heart of everything she and her staff do. Dr. Perijoc continually adds to her skill set and is currently pursuing a Master in Functional Medicine degree with George Washington University in Washington, D.C.

Dr. Perijoc is a distinguished figure in her field, undertaking teaching roles at several Texas universities and holding membership of the American College of Physician Executives and the American Medical Directors Association, for whom she is a certified medical director for nursing homes. Dr. Perijoc also provides comprehensive and compassionate care and support for patients and their loved ones at hospice facilities across Texas.

Dr. Perijoc is an extraordinary physician who sets standards other medical professionals rarely match. The residents of Plano are fortunate to have a doctor of her caliber caring for their health.

Kenney Weinmeister, MD is a highly experienced and board-certified pulmonologist, and critical care specialist who has been serving the community of Dallas, Texas, with distinction since 1993 as a member of Southwest Pulmonary Associates. With decades of clinical expertise and a strong academic foundation, Dr. Weinmeister is committed to delivering personalized, comprehensive care for patients with a range of respiratory and sleep-related conditions.

Dr. Weinmeister earned his Bachelor of Science in Pharmacy from Southwestern Oklahoma State University in Weatherford, Oklahoma, and went on to complete his Doctor of Medicine at the University of Oklahoma College of Medicine. He pursued fellowship training in Pulmonary and Critical Care Medicine at UT Southwestern Medical School in Dallas, one of the country’s premier academic institutions. Further enhancing his expertise in healthcare management, he also earned a Master of Business Administration (MBA) from the University of Texas at Dallas.

Dr. Weinmeister has been the recipient of D Magazine's Best Docs recogniztion several times, most recently in 2025. 

He holds board certifications in Pulmonary Medicine, and Critical Care Medicine. His clinical interests include robotics bronchoscopies with early diagnosis and treatment of complex sleep disorders, as well as chronic respiratory illnesses such as asthma, COPD, interstitial lung disease, and respiratory failure.

Dr. Weinmeister is known for his thorough, compassionate approach and his dedication to improving his patients’ long-term health and quality of life. His blend of clinical excellence and leadership continues to make him a trusted resource in pulmonary and sleep medicine across Dallas and beyond.

Rebecca Doebele, MD, is a board-certified pulmonologist and critical care specialist who has been providing expert respiratory care to patients in Dallas, Texas, since joining Southwest Pulmonary Associates in 2008. Known for her compassionate approach and clinical excellence, Dr. Doebele treats a wide range of pulmonary conditions, including asthma, COPD, interstitial lung disease, and critical illnesses requiring intensive care.

Dr. Doebele earned her Bachelor of Science in Genetics from Texas A&M University in College Station before completing her Doctor of Medicine at the University of Texas Southwestern Medical School in Dallas. She remained at UT Southwestern for her residency in Internal Medicine, then pursued advanced fellowship training in Pulmonary and Critical Care Medicine at the University of Colorado Health Science Center.

Board-certified in both Pulmonary Medicine and Critical Care Medicine by the American Board of Internal Medicine, Dr. Doebele has been repeatedly recognized for her clinical skill and dedication to patient care. She was named a Super Doctors Rising Star in 2012 and has earned the prestigious Texas Super Doctors distinction annually from 2013 to the present. Additionally, she received the “Physician All-Star” award from the nursing and administrative staff at Texas Health Presbyterian Hospital of Dallas, a testament to her leadership and collaboration in the hospital setting. Dr. Doebele has been recognized as one of D Magazine’s best doctors in 2021, 2023, and 2024. She also serves as the ICU Medical Director at Texas Health Dallas. 

Outside of medicine, Dr. Doebele enjoys traveling and spending time with her husband and their three children. She is proud to serve the Dallas community and is committed to helping her patients breathe easier and live healthier lives.

Tayler Long, MD, is a board-certified pulmonologist at Southwest Pulmonary Associates in Plano, Texas. He is committed to providing excellent pulmonary and critical care medicine to the community. 

Dr. Long earned his Bachelor of Arts in Human Biology from Stanford University in Palo Alto, California, before completing his Doctor of Medicine at the University of California, San Diego School of Medicine. He went on to complete both his residency in Internal Medicine and his fellowship in Pulmonary and Critical Care Medicine at the prestigious UT Southwestern Medical School in Dallas, Texas.

In addition to his clinical training, Dr. Long holds a Master of Science in Healthcare Leadership and Management from UT Dallas, equipping him with the tools to lead effectively in today’s evolving healthcare landscape. His advanced education and years of experience allow him to offer expert care in managing complex lung diseases, respiratory failure, and critical illness.

Dr. Long joined Southwest Pulmonary Associates in 2007. He has served as President of the Medical Staff at Texas Health Plano and currently holds leadership roles on the Medical Executive Committee at Texas Health Frisco. He also serves as the Director of the ICU at Texas Health Frisco, reflecting his commitment to both patient care and institutional excellence. He is has been recognized as one of D Magazine's Best Docs repeatedly, most recently in 2025.

Outside of medicine, Dr. Long is a devoted husband and father. He is married and enjoys spending time with his three beautiful children.

Anthony Ortegon, MD, is a board-certified pulmonologist, critical care specialist, and sleep medicine physician providing expert care to patients in Dallas, Texas. Since joining Southwest Pulmonary Associates in 2013, Dr. Ortegon has been dedicated to helping individuals manage a wide range of respiratory and sleep-related conditions with compassionate, evidence-based care.

Dr. Ortegon earned his Bachelor of Arts in Biology from Swarthmore College in Pennsylvania and went on to receive his Doctor of Medicine from Temple University in Philadelphia. He completed both his residency in Internal Medicine and his fellowship in Pulmonary and Critical Care Medicine at UT Southwestern Medical School in Dallas, one of the nation’s leading academic medical centers.

He is triple board certified by the American Board of Internal Medicine in Internal Medicine, Pulmonary Medicine and Critical Care Medicine. Dr. Ortegon specializes in the diagnosis and treatment of conditions such as asthma, COPD, interstitial lung disease, pulmonary hypertension, and sleep apnea. Dr. Ortegon has a special interest in the diagnosis of various lung pathologies requiring multiple advanced bronchoscopy procedures, including Ion robotic bronchoscopy. Overall, his clinical approach emphasizes clear communication, individualized care plans, and a strong commitment to improving his patients’ overall health and quality of life.

Known for his thoroughness and approachability, Dr. Ortegon values the long-term relationships he builds with his patients. He is proud to be part of the Southwest Pulmonary Associates team and to serve the Dallas community with integrity and expertise.

Munir Hazbun, MD, is a board-certified pulmonologist, critical care specialist, and sleep medicine physician serving patients in Dallas, Texas. He joined Southwest Pulmonary Associates in 2008 and brings a wealth of experience and a patient-centered approach to the diagnosis and treatment of complex respiratory and sleep disorders.

Originally from Santiago, Chile, Dr. Hazbun earned his medical degree from the prestigious Universidad de Chile. He completed his internship at Texas Tech Health Science Center in El Paso and went on to pursue fellowship training at Baylor College of Medicine in Houston, where he specialized in Pulmonary, Critical Care, and Sleep Medicine.

Dr. Hazbun is quadruple board certified by the American Board of Internal Medicine in Pulmonary Medicine, Sleep Medicine, and Internal Medicine. His clinical interests include persistent cough, shortness of breath, lung cancer, sarcoidosis, and complex sleep-related breathing disorders. Known for his thoughtful, comprehensive care, he works closely with each patient to identify the root cause of their symptoms and create personalized treatment plans.

Fluent in both English and Spanish, Dr. Hazbun is committed to serving the diverse needs of the Dallas community. He has been named among D Magazine's Best Doctors and recognized as a Texas Super Doctor from 2010 to 2015 and again in 2025. He has also served as a board member for the local chapter of the American Lung Association.

Outside of medicine, Dr. Hazbun enjoys spending time with his wife, Dr. Pilar Bescos, a family medicine physician, and their two children. His personal interests include biking, pickleball, golf, learning piano, gardening and traveling with his family.

Arhaanth Reddy, MD, is a board-certified pulmonologist at Southwest Pulmonary Associates in Plano, Texas. He is known for his expertise in diagnosing and treating complex respiratory conditions and for delivering evidence-based care with compassion and precision.

Dr. Reddy earned his medical degree from the University of California, San Diego School of Medicine, and completed his residency in internal medicine at UT Southwestern Medical School in Dallas, Texas. He went on to complete a fellowship in pulmonary and critical care medicine at UT Southwestern, where he also earned a Master of Science in Healthcare Leadership and Management. His academic excellence was recognized early on with election to the Alpha Omega Alpha Honor Medical Society and the prestigious Richard Mays Smith Award in Internal Medicine.

Dr. Reddy is triple board-certified by the American Board of Internal Medicine in Critical Care Medicine, Neurocritical Care Medicine, and Pulmonary Medicine.

In addition to his clinical work, Dr. Reddy serves as the current Vice Chair of the Department of Medicine at Texas Health Plano, where he helps shape the future of patient care, quality, and medical education.

Dr. Reddy offers a comprehensive range of advanced diagnostic procedures, including robotic bronchoscopy, endobronchial ultrasound (EBUS), and integrated 3D fluoroscopy, providing patients with cutting-edge evaluation and treatment options.

He has also been the recipient of several awards, including the:

• Alpha Omega Alpha Honor Medical Society, 2011
• Richard Mays Smith Award in Internal Medicine, UT Southwestern, 2011

Dr. Reddy chose a career in pulmonary and critical care medicine because he enjoys complex problem-solving and transforming insights into better outcomes for his patients.

Outside of medicine, he enjoys traveling, photography, reading, and, most of all, spending time with his three wonderful children.

Ross Schumacher, MD, is one of the skilled pulmonologists practicing at the Southwest Pulmonary Associates location in Plano, Texas. He is a versatile and compassionate pulmonary physician who joined Southwest Pulmonary Associates in 2023. His medical journey encompasses intensive care expertise and long-term patient relationships.

Dr. Schumacher completed his undergraduate studies at Indiana University in Bloomington, Indiana. He then went on to complete his Doctor of Medicine at the Indiana University School of Medicine in Indianapolis. He completed his fellowship at the University of Alabama at Birmingham (UAB) and his residency at the University of Texas-Southwestern. He earned the Critical Care Fellow of the Year at UAB in 2022 and the House Officer of Excellence at UT Southwestern in 2019. 

Dr. Schumacher is board-certified in Internal Medicine, Critical Care Medicine, and Pulmonary Medicine by the American Board of Internal Medicine. He has also been a member of CHEST and the American Thoracic Society (ATS) since 2020. Additionally, Dr. Schumacher is an advanced bronchoscopist with a focus on the robotic sampling of micronodules. 

Outside of medicine, Dr. Schumacher finds joy in his family—married to Victoria in 2020, welcomed son Dean Wilder in 2021—and a loyal dog named Hoosier. Dr. Schumacher's interests span from Kurt Vonnegut's literature to Immanuel Kant's philosophy. He's dedicated to evidence-based medicine, writing, and passionately cheering for the Hoosiers and Cowboys sports teams.

To schedule an appointment with Dr. Schumacher and the Southwest Pulmonary Associates team, call the office or request an appointment online today.

Mark Robertshaw, MD, is a board-certified pulmonologist and critical care medicine specialist proudly serving patients in Plano, Texas. He joined Southwest Pulmonary Associates in 2023, bringing with him a wealth of clinical experience and a compassionate, patient-centered approach to care.

Dr. Robertshaw completed his fellowship in Pulmonary and Critical Care Medicine at UT Southwestern Medical Center in Dallas, Texas, where he was honored to serve as Chief Fellow during the 2022–2023 academic year. He completed his residency training at Duke University Hospital in Durham, North Carolina, and earned his medical degree from the University of Missouri in Columbia. His academic journey began at the University of Notre Dame in South Bend, Indiana, where he received his Bachelor of Science and developed a lifelong passion for Fighting Irish football.

Board certified by the American Board of Internal Medicine in both Pulmonary Medicine and Critical Care Medicine, Dr. Robertshaw is committed to helping patients manage a wide range of respiratory conditions with leading-edge diagnostic tools and individualized treatment plans. His dedication to community service has been recognized with prestigious honors, including the President’s Volunteer Service Award and the Congressional Award, both received in 2013.

Outside the clinic, Dr. Robertshaw enjoys spending quality time with his wife and daughter, golfing, and cheering on his alma mater during college football season. He looks forward to building long-lasting relationships with his patients and their families throughout the Plano community.

123 Welcome Our mission here at the Natural Balance Clinic is to introduce the most natural nutrition and supplements to balance the body without using medication. We believe that medication, for the most part, is not the answer for common illnesses. We believe that most diseases and illnesses happen because of the lack of healing nutrients in common food choices. We believe that medications are temporary relief of more in depth medical problems that need serious nutritional attention. We believe that healing should start from inside the body and unless we begin from inside the body, we never can treat outside symptoms because outside body pain and symptoms arise from serious internal imbalance which arise from toxins that we constantly abuse our body with, calling them "food".

Bishwas Upadhyay, MD, is a board-certified internal medicine physician at Texas Primary & Pediatric Care in Irving & Celina, Texas. Dr. Upadhyay’s philosophy in medicine is to help the body care for itself. He strongly believes in the power of preventive medicine and places high importance on the doctor-patient relationship. He is known for being attentive and articulate, and finds joy in educating and counseling his patients. 

Dr. Upadhyay is originally from the Himalayan country of Nepal. He graduated from Nepalgunj Medical College in Nepal and completed his residency training in internal medicine at Presence Saint Joseph Hospital in Chicago, Illinois, where he served as a chief resident. Afterward, he joined the University of Nevada Reno School of Medicine as an assistant professor of medicine and later served as an academic hospitalist and associate program director for their internal medicine residency program. 

In addition to taking care of his patients in the hospital, Dr. Upadhyay also taught medical students and residents in both hospital and primary care settings. During his tenure as the associate program director at the University of Nevada, he developed a quality improvement and patient safety curriculum. He also coached and mentored residents in their quality improvement and patient safety projects. 

In addition to his board-certification, Dr. Upadhyay is a fellow of the American College of Physicians and received several awards and recognitions throughout his medical career. Dr. Upadhyay is fluent in English, Nepali, Hindi, and Urdu, allowing him to better serve the diverse patient populations in his community.

Outside of work, Dr. Upadhyay loves hiking, spending time with his family, and traveling. He is also an amateur cook.