PCMS Leadership
Pima County Medical Society Officers - 2026
Michael DeLong, MD
President
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Dr. Michael DeLong is a board-certified nephrologist and internist who has been practicing medicine in Tucson since 1999 and has been with Arizona Kidney Disease & Hypertension Centers (AKDHC) since 2007.
Having called Tucson home for nearly three decades, Dr. DeLong is deeply invested in the health and well-being of the Southern Arizona community and is passionate about strengthening the local physician network. Throughout his career, he has been a strong advocate for physician collaboration, mentorship, and creating meaningful opportunities for physicians to connect and support one another.
As President of the Pima County Medical Society, Dr. DeLong is focused on fostering engagement among physicians at all stages of their careers while helping shape the future of medicine in Pima County. He is committed to building a strong, connected physician community that supports both current and future generations of healthcare leaders.
Lourdes Castanon, MD
Vice President
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Dr. Lourdes Castañón, MD, FACS is the Director of the Burn Program at Banner – University Medical Center Tucson and a Clinical Associate Professor of Surgery at the University of Arizona College of Medicine – Tucson. A board-certified general surgeon and surgical critical care specialist, she completed fellowships in burns, surgical critical care, acute care surgery, and trauma following her residency in general surgery.
As Vice President of the Pima County Medical Society, she is committed to strengthening physician engagement, advancing advocacy, and fostering collaboration throughout Southern Arizona's medical community.
Dr. Castañón is fluent in both English and Spanish.
Roy Loewenstein, MD
Past President
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Dr. Roy Loewenstein, MD, FACP is an internal medicine physician with Rillito Internal Medicine and has been serving the Tucson community for more than two decades.
He joined Arizona Community Physicians in 2005 and is also a core faculty member in the Tucson Medical Center Internal Medicine Residency Program, where he is dedicated to mentoring the next generation of physicians.
As a member of the PCMS Board of Directors, Dr. Loewenstein is committed to advancing physician collaboration and supporting high-quality patient care throughout Pima County.
Emma Jensen
Executive Director
Emma supports the PCMS Board and membership by overseeing daily operations, communications, strategic initiatives, and partnerships. She works closely with physician leadership to advance PCMS’s mission, advocacy efforts, and member engagement.
Email:
ejensen@azmed.org
Phone:
520-795-7985
Office Hours: M-F, 8 a.m. to 5 p.m.
Pima County Medical Society Officers - 2026
Berna Villanueva, MD
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Dr. Berna Villanueva, MD, is an internal medicine physician at Banner – University Medical Center Tucson and Banner – University Medical Center South. A graduate of the University of Arizona College of Medicine, she specializes in preventive care, HIV primary care, and health promotion, with a focus on improving patient health through education and compassionate care.
As a member of the Pima County Medical Society Board of Directors, Dr. Villanueva supports the Society's mission of strengthening the physician community through collaboration, education, and advocacy while fostering meaningful connections across Southern Arizona.
Billie Bixby, MD
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Dr. Billie Bixby, MD, is an interventional pulmonologist at Banner – University Medical Center Tucson and Banner – University Medical Center South, specializing in pulmonary disease and advanced lung procedures. She is committed to providing individualized, patient-centered care while helping patients make informed decisions about their health.
As a member of the Pima County Medical Society Board of Directors, Dr. Bixby supports the Society's mission of strengthening the physician community through collaboration, education, and advocacy, while helping foster meaningful connections among physicians throughout Pima County.
Julie Jernberg, MD
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Dr. Jernberg is a clinical professor of medicine at the Univ of Arizona College of Medicine-Tucson and is the director for the Ambulatory Medicine Clerkship.
She is Board Certified in Internal Medicine, Geriatrics, and Integrative Medicine and her clinical work is in the Internal Medicine Residents’ clinics.
In addition to education, her interests include the climate impacts on health, One Health (animal-human-environment health), and Theraplay® (a play-based method to (re)build healthy attachment currently used in 40+ countries).