Chief Medical Officer

Tollie Elliott, MD

Dr. Elliott holds a Bachelor of Science from Howard University and a Post Baccalaureate degree from Fisk University. He attended Howard University College of Medicine and obtained his Doctor of Medicine degree in 2000. He completed his residency in the Department of Obstetrics and Gynecology at Georgetown University in 2004 and was named Outstanding Senior Resident in Gynecology. Dr. Elliott is Board-certified. He is committed to community development, having taught in the Prince George’s County Public Schools and served as director of a mentoring program for at-risk youth early in his career. Dr. Elliott enjoys family life, music and travel. Prior to rejoining Mary’s Center, Dr. Elliott worked at Providence Hospital in Washington, DC, where he was a Staff Physician and Co-Chair of the Ob/Gyn Department in 2014. He also served as an Associate Professor at Howard University Hospital. Dr. Elliott was recognized as a Washingtonian Top Doctor in 2016.



Kristina Andersson, DO, FAAP (Medical Director, Silver Spring site)

Board certified pediatrician Kristina Andersson sees patients at the Mary's Center site on Flower Avenue in Silver Spring, Maryland. Certified by the American Board of Pediatrics, she attended Arizona College of Osteopathic Medicine and completed her residency at Georgetown University Hospital. She speaks English and Spanish and has been a member of the Mary's Center team since November 2009. In her spare time, Dr. Andersson enjoys: running, swimming, biking, gardening, and playing soccer with her son.



Anne Carpinelli, MD, MPH, FAAP (Medical Director, Georgia Avenue site)

Pediatrician Dr. Anne Carpinelli is the Medical Director for our Georgia Avenue site. She joined Mary’s Center staff in September 2013. Dr Carpinelli says “I chose to work at Mary’s Center because I have a strong interest in ensuring that the social determinants of health are addressed, particularly for vulnerable populations, such as new immigrants and the families of children with special needs. I enjoy working here because of my wonderful colleagues and the warm-hearted patients we serve.” She studied medicine at the University of Illinois-Chicago and completed her residency at Boston Children’s Hospital/Boston Medical Center. Her research interests include quality improvement and care coordination within the family-centered medical home. Originally from Kansas, Dr Carpinelli speaks English and Spanish. She jokingly adds that she also speaks “Baby-nese”! During her free time she enjoys singing, playing piano, writing, doing yoga and pilates, and going to the park or museums with her family.


Christian Cornejo, MD, FAAP (Senior Administrative Medical Director and Medical Director, Adelphi site)

Dr. Cornejo serves Mary's Center’s participants as a board certified pediatrician. He is also the Senior Administrative Medical Director at Mary's Center. Dr. Cornejo attended medical school at Universidad Peruana Cayetano Heredia and completed his residency at the University of Tennessee College of Medicine in Chattanooga. He  has been a member of the Mary's Center team since November 2009 and speaks English and Spanish. Dr. Cornejo enjoys mountain biking, painting and traveling with his wife.



Paul J. Doherty, MD, FAAP (LGBTQ, Adolescent Clinical Lead)

Board Certified Pediatrician Paul J. Doherty, fluent in Swahili and English, joined the Mary Center’s team in August 2013. Before attending Medical School at Johns Hopkins School of Medicine, Dr. Doherty volunteered for the Peace Corps in East Africa and for a HIV and GLBT healthcare organization in D.C. In his free time, he enjoys: yoga, skiing, hiking, travel, cooking and gardening.




Dr. Maria L. Marquez

Maria L. Marquez, MD, FAAP (Medical Director, Fort Totten site)

Dr. Maria L. Marquez is a Board Certified pediatrician who completed her internship, residency and chief residency in the Pediatrics Department at Georgetown University.  After her training, Dr. Marquez joined the faculty at Georgetown University Hospital, where she has been practicing and teaching since 1999.  She has been frequently recognized as a Washingtonian Top Doctor, and developed a medical educator career as Associate Dean of Reflection and Professional Development and Full Professor of the Department of Pediatrics at Georgetown University School of Medicine.  In addition Dr. Marquez has served in the American Academy of Pediatrics (AAP) at national and regional levels; passionately  advocating children's oral health as theirs overall health, as Co-Founders of the District of Columbia’s Oral Health Coalition, and Co-Chair of the Dental-Medical Collaboration group.  She is very proud to be a member of the Mary’s Center team, and to serve as Director of the Clinic at Fort Totten. Dr. Marquez values a holistic approach to health.  On a personal level she enjoys travelling, music, cooking and going to the museums with her family.


Karen Mazie, MD, FAAP

Dr. Mazie has been a Mary’s Center pediatrician since November 2004 and sees patients at the Mary’s Center site on Georgia Avenue in Petworth, D.C. Fluent in English and Spanish, she attended medical school at Wake Forest University and completed her residency at Brown University’s Hasbro Children’s Hospital. In her spare time, Dr. Mazie enjoys gardening, good food and spending time with her children.




Dr. Mike NdelMichael Nidel, MD

Dr. Mike Nidel joined the pediatric team at Mary’s Center in Adelphi in September 2017. Before his medical training, he received a BS in Computer Engineering from Penn State University and a BS in Computer Science from Stanford. He worked as a software programmer for eight years, but finally decided to change to a more meaningful career in medicine. After a post-baccalaureate program at University of Maryland, he attended medical school in beautiful Charlottesville at the University of Virginia. He completed his pediatric residency training at the University of North Carolina in Chapel Hill. One thing he loved about both of those medical centers was their commitment to care for ALL patients and families, regardless of their background, beliefs or income. He was thrilled to find a place like Mary’s Center, taking that mission to the next level, providing services that attempt to reach those who otherwise would not have access to them. Outside the office, he loves spending time with his wife and two kids, and enjoys playing soccer, going to see the Washington Capitals hockey team, playing the guitar and singing. He even recorded a full-length rock album all on his own!


Christine "Bertha" Pham, MD

Dr. Christine "Bertha" Pham joined Mary's Center in 2017 as a pediatrician at Fort Totten. She has always enjoyed working within communities, and is proud to be part of Mary's Center's mission to help families move up the economic ladder. Her special interests include financial inclusion and community economic development. She graduated from Yale College, after which she served in Mali, West Africa, with the US Peace Corps. She earned her MD from Harvard Medical School and completed her training with the Brown University Pediatrics program. A native Northern Virginian, she is thrilled to be back home. Dr. Pham speaks Spanish, Bambara, and Vietnamese.


Dr. Stephanie PopeStephanie Pope, MD

Dr. Stephanie Pope holds a Bachelor of Arts degree in Ecology and Evolutionary Biology from Princeton University. She completed medical school at the University of Maryland and her pediatric residency at Georgetown University in 2010. She especially enjoys working with children with special health care needs and adolescents. She speaks English and Spanish. Dr. Pope says: "I am grateful that I can work as part of a large experienced multi-disciplinary team to help patients overcome social and economic barriers to accessing quality health care with dignity. It is absolutely possible to attain social change through medicine and good health". In her free time, Dr. Pope enjoys mentoring students, exploring museums with her son and husband, experiencing new cultures, science fiction and pupusas.


Jessica Schroeder, MD, MPH, FAAP (Medical Director, Ontario Road site)

A pediatrician and Medical Director for our Ontario Road site in Adams Morgan, Dr. Jessica Schroeder sees patients at that location. She attended Medical School at the Medical College of Virginia (VCU School of Medicine) and completed her residency at Children's National Medical Center. Dr. Schroeder has been a member of the Mary's Center team since 2002 and speaks English and Spanish. She has lived in Washington, D.C. since 1999 and has three children - all born at home. In her free time, Dr. Schroeder enjoys running, gardening, and hiking. Dr. Schroeder says: "I love coming to work every day to see my patients grow and change. I also really enjoy helping children feel better when they are sick. We have great staff here and wonderful patients.”


Marlorie Stinfil, MD, FAAP (Associate Medical Director, Georgia Avenue site)

Dr. Marlorie Stinfil is a board certified pediatrician who has been a member of the Mary's Center team since March 2009. She sees patients at the Mary's Center site on Georgia Avenue in Petworth, D.C. Born and raised in New York City, she attended medical school at the Weill Medical College of Cornell University and completed her residency at New York University Langone Medical Center. Dr. Stinfil speaks English and medical Spanish. In her free time, Dr. Stinfil enjoys baking, listening to music and traveling. Dr. Stinfil says: "I chose to work at Mary's Center because I wanted to work for an organization that provided wrap-around care (medical/behavioral/dental/social) to patients of all walks of life regardless of their ability to pay."


Letizia Valentín-Friebele, MD, FAAP

Dr. Letizia Valentín-Friebele joined Mary’s Center in September 2017 and see participants at the Georgia Avenue location.  Born and raised in Manhattan, New York, she earned a Bachelor’s Degree in Art History from Fordham University.  She later received her Medical Degree from Howard University College of Medicine and completed her pediatric residency at INOVA Fairfax.  She is fluent in both English and Spanish.  Prior to entering the medical field, she was formally trained as a dancer and singer, and remains an enthusiast of the performing arts.  During her free time she enjoys, spending time with her husband and family and going for runs with her dog.


Gelane Workneh, MD, FAAP (Clinical Clerkship Lead)

Board Certified in pediatrics, Dr. Workneh joined Mary’s Center in August 2015 and is based at our Georgia Avenue location. She was born and raised in Addis Ababa, Ethiopia, and speaks Amharic and English. Dr Workneh studied medicine at the University of Illinois and completed her residency at the University of Chicago. Before moving to the DC area, she spent three and a half years in Botswana and Ethiopia, working in pediatric HIV care and treatment. When she is not working, Dr. Workneh enjoys fixing things around her house, gardening, traveling, and finding hidden music and art venues in the area. Dr Workneh says: It is quite humbling to be part of a team that advocates for communities that do not usually have voices and provides quality healthcare and ancillary and essential support to families.” 

Family Medicine/Adult Clinicians

Tirsit Adane, MD (Adolescent Clinical Lead)

Board Certified in Family Medicine, Dr Tirsit Adane joined Mary’s Center in August 2015. She practices at our Georgia Avenue location in Washington DC. Dr. Adane attended Meharry Medical College and completed her residency at Columbia University/New York Presbyterian Hospital. She speaks some Spanish and Amharic and enjoys traveling, long distance running, and trying new recipes. Dr. Adane says: “I chose to work at Mary’s Center because of their admirable mission to serve to community, as well as the opportunity to take care of the whole family from a holistic point of view.”



Gita Agarwal, MD

Dr. Agarwal practices Family Medicine at the Mary’s Center site on Ontario Road in Adams Morgan, DC. She attended medical school in Karachi, Pakistan and completed her residency in Alabama. Dr. Agarwal joined the Mary’s Center team in July 2008 due to her interest in practicing primary care in a community setting with a wide range of ages and races as well as medical and social challenges. She speaks English, Urdu, Hindi, and medical Spanish. In her spare time, Dr. Agarwal enjoys cooking, learning about other cultures, and raising her two children.



Dr. Caroline GeddesCaroline Geddes, MD

Dr. Geddes joined Mary’s Center in May 2017.  She is a board -certified family physician working at our Ontario Road site.  She completed her undergraduate degree at the University of Virginia, then moved to Philadelphia to work as an AmeriCorps volunteer at the YouthBuild Charter School.  She attended medical school at Drexel University and did her residency at the University of Pennsylvania Department of Family Medicine and Community Health.  Following her residency, she stayed on as faculty at the University of Pennsylvania before joining Doctors Without Borders.  With this international aid organization she worked to start a hospital in a refugee camp in Ethiopia, as part of an emergency team for a measles outbreak in the Democratic Republic of the Congo, and as a supervising physician at a hospital in a rural area of the Central African Republic.  She has now settled down in Washington. DC, where she enjoys bike-riding, gardening, and eating her husband’s cooking.  She is excited to be a part of the multi-disciplinary team at Mary’s Center and to provide high quality care to people from a variety of backgrounds and cultures.  Dr. Geddes speaks English and French, and is working on Spanish.


Dr. HayashiA Seiji Hayashi, MD

Dr. Hayashi is a board-certified family physician and Fellow of the American Academy of Family Physicians. He has been caring for patients in community health centers for 20 years. In addition to clinical care, he is an experienced executive in primary care practice, health policy, and health information technology. He has been a faculty memberand leader at Georgetown University and George Washington University. Dr. Hayashi also served as Chief Medical Officer for the Bureau of Primary Health Care, the federal agency that oversees all federally qualified health centers. While caring for patients at Mary’s Center, he is also the Director of Medicine for Human Dx, a technology project to enhance access to care. Dr. Hayashi graduated with honors from Vassar College with a degree in Studio Art. He received his medical degree from the Albert Einstein College of Medicine and was inducted into the Alpha Omega Alpha medical honor society. After completing his Family and Community Medicine Residency Program at the University of California San Francisco, he received his Master of Public Health degree from the Harvard School of Public Health while serving as a fellow for the Commonwealth Fund/Harvard University Fellowship in Minority Health Policy. 


Kelechi NdubuizuKelechi Ndubuizu, MD, MPH

Dr. Kelechi Ndubuizu is a Board-Certified family medicine physician. She obtained her Bachelor of Science from University of Maryland, Baltimore County and her Masters of Public Health from University of North Carolina at Chapel Hill. She attended Duke University School of Medicine and completed her residency at Carolinas Medical Center in Charlotte, NC.  Her clinical interests include community medicine, addressing health disparities, teaching, and mentorship. In her free time, Dr. Ndubuizu enjoys traveling, exercising, and spending time with family and friends.



Dr. Daniel SmithDaniel Smith, MD

Dr. Smith joined Mary’s Center in August 2015 and practices Family Medicine at our Ontario Road location. After his undergraduate studies at the University of Virginia, he worked as a high school teacher in Anacostia, DC. He then attended the University of Pennsylvania School of Medicine and completed his residency at Swedish First Hill Family Medicine at the Downtown Public Health Center in Seattle, WA. Dr. Smith has had very rewarding medical experiences working and volunteering in Peru, Guatemala, Haiti and Malawi. He has a particular interest in the care of new mothers and their babies, geriatric patients and patients recovering from addiction. In his free time, Dr. Smith enjoys spending time with his wife and 2 children, hiking, fishing and cheering on University of Virginia sports teams! Dr. Smith says: “I chose to do my residency at a community health center and now work at Mary’s Center because I wholeheartedly believe access to high-quality health care is something that all people are entitled to regardless of their native language, immigration status, skin color or ability to pay. We are all neighbors and should work together to promote the health of our communities!”


Dana Mueller, MD (Director of Adult and Family Medicine)

Dr. Dana Mueller is board certified in Internal Medicine. She studied Medicine at the University of Virginia and completed her residency at Johns Hopkins Hospital in Baltimore, Maryland. She joined Mary’s Center in August 2014 and sees patients at the site on Georgia Avenue in Petworth. Dr. Mueller, who speaks English and Spanish, is particularly interested in patient education and self-advocacy and Hepatitis C. She enjoys baking, running, playing soccer and playing with her nieces and nephews.



Dr. Ashley Harris, Internist at Mary's  CenterAshley Harris, MD, MHS (Adult Quality and Improvement Lead)

Dr. Ashley Harris is an Internist at Mary’s Center. She attended Georgetown Medical School, and completed her residency in Internal Medicine at Brigham and Women’s Hospital. After completing a fellowship in General Internal Medicine, during which she focused on research to improve health disparities among low income women, Dr. Harris joined the staff at Mary’s Center in September 2015, and sees patients at the Montgomery County and Prince George’s County locations.



Dr. Shantanu NundyShantanu Nundy, MD, MBA

Board certified in internal medicine, Dr. Nundy joined Mary’s Center in 2013. Dr. Nundy received his B.S. from MIT, an M.D. from the Johns Hopkins University School of Medicine, an M.B.A. from the University of Chicago Booth School of Business, and trained in internal medicine at the University of Chicago Medical Center. Dr. Nundy is also Director of the Human Diagnosis Project Nonprofit, an online system built by the world’s doctors that maps the steps to help any patient. Prior to the Human Diagnosis Project, Shantanu was Managing Director for Clinical Innovation at Evolent Health, a population health management company, and co-founded mHealth Solutions, a mobile messaging startup for patients with chronic illness. His first book, "Stay Healthy At Every Age: What Your Doctor Wants You to Know," was chosen as one of the top 5 health books of 2010 by Wall Street Journal Online.



Martin J. O'Hara, MD (Cardiologist and Internist)

Dr. Martin O’Hara studied at University College, Dublin, National University of Ireland and completed his residency at Mount Sinai Medical Center and Columbia University/Presbyterian Hospital, both in New York City. Board-certified in Internal Medicine and Cardiology, he specializes in adult cardiology and sees patients at our Georgia Avenue clinic. He joined the Mary’s Center team in November 2014. Dr. O’Hara speaks Spanish, French and German and enjoys traveling, politics and international affairs, reading and soccer. Dr. OHara says: “I like to practice medicine because it combines modern science and exciting advances with getting to know and helping people.  As the phrase goes, I am “translating” the knowledge acquired through research into improving the lives of ordinary people. I choose to work at Mary’s Center because it uniquely tries to meet the needs of people who otherwise would not have access to quality medical care.  The people who work at Mary’s Center all have a sense of mission to provide the best care to our patients.”


Infectious Diseases 

Sarah Ali, MD (Infectious Disease Specialist) 

Board Certified in both Internal Medicine and Infectious Diseases, Dr Sarah Ali joined the Mary’s Center team in August 2015. She is based at our Georgia Avenue site in Petworth, DC. Dr. Ali attended American University of the Caribbean. She did her internship and residency in Internal Medicine at Saint Vincent’s Catholic Medical Center in Manhattan. She also completed the Infectious Disease Fellowship Program at George Washington University School of Medicine and Health Sciences. Dr. Ali, who is from Lafayette, Louisiana, speaks English and enjoys swimming, running and painting.


Obstetrics and Gynecology (OB/GYN)

Prathap Naini, MD (Director of Women's Health)
Dr. Prathap Naini, who is from Rockland County, New York, joined Mary’s Center in August 2015 and is based at our Georgia Avenue site. He studied at Tufts University School of Medicine in Boston and completed his residency at Pennsylvania Hospital in Philadelphia. Dr. Naini received the National Health Service Corps scholarship and the Society for Maternal Fetal Medicine Outstanding Resident in Obstetrics award. His professional interests include family planning, high risk obstetrics, and labor and delivery, while his personal interests include cooking, film and stand-up comedy. Dr. Naini says: “I chose to practice medicine specifically to address health care disparities and provide care to those with less access to resources. I am a strong believer in equal access to high quality health care and chose to work at Mary’s Center because of our common mission."


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