Meet the Providers

Dr. Wilson Jackson, MD, FACP, FACG, AGAF

Dr. Wilson Jackson, MD, FACP, FACG, AGAF Dr. Wilson Jackson received his undergraduate degree from Bowdoin College cum laude in English literature and his Doctor of Medicine degree from Northwestern University in Chicago. He completed a residency in internal medicine at Northwestern Memorial Hospital and a fellowship in gastroenterology and hepatology at Thomas Jefferson University in Philadelphia. Training in advanced therapeutic endoscopy was completed at Temple University Hospital. He was a faculty member at Temple University Medical Center, where he was an assistant professor in the Division of Gastroenterology before moving to the Harrisburg area.  He has particular interest in Crohn’s Disease and Ulcerative Colitis and eosinophilic esophagitis.

Dr. Jackson is board certified in internal medicine and gastroenterology/hepatology. He was elected a fellow of the American Gastroenterology Association, American College of Physicians, and American College of Gastroenterology. He is also a member of the Pennsylvania Medical Society, American Medical Association, American Society of Gastrointestinal Endoscopy and Pennsylvania Society of Gastroenterology. He has also served as president of the latter.  He currently serves on the board of trustees for the Pennsylvania Medical Society.

Dr. Jackson has served on the National Affairs Committee for the American College of Gastroenterology. He has presented papers at national medical meetings, and has written chapters for medical textbooks.  In 2009, he was selected as the Physician of the Year for the Delaware Valley Crohn’s and Colitis Foundation.  He wrote an iphone app on eosinophilic esophagitis, EoE Tracker (www.i-gastro.net) to help educate and manage patients with eosinophilic esophagitis.

Dr. Paul G. Lacey, MD, FACP, FACG

Dr. Paul G. Lacey, MD, FACP, FACG Dr. Paul Lacey received his undergraduate degree from Villanova University.  He graduated Magna Cum Laude in biology. He received his Doctor of Medicine degree from Pennsylvania State University.  He is Board Certified in Gastroenterology and Internal Medicine.  He completed his Internal Medicine Residency at the University of Virginia.  His Gastroenterology/Hepatology fellowship was completed at Pennsylvania State University, where he later served as a Clinical Instructor.

He has achieved Fellowship status in The American College of Gastroenterology and The American College of Physicians.  Dr. Lacey participates in continuing medical education programs.  He has completed board re-certification in Gastroenterology and Internal Medicine.  Dr. Lacey and his family have lived in Central Pennsylvania for over 27 years.  He is a staff member at the PinnacleHealth Hospitals and the Holy Spirit Hospital.

Dr. John J. Michel, DO

Dr. John J. Michel, DO Dr. John Michel received his undergraduate degree in pharmacy from Ohio Northern University and his Doctor of Osteopathy degree from Philadelphia College of Osteopathic Medicine in Philadelphia, PA. He completed his internal medicine residency at Philadelphia College of Medicine, where he was chief internal medicine resident his last year. He completed a fellowship in gastroenterology and hepatology at the University of Medicine and Dentistry of New Jersey with rotation at Hackensack University, University Hospital, East Orange Veterans Administration Hospital and Liver Institute of Newark, New Jersey. He was chief gastroenterology fellow his last year of training before moving to the Harrisburg area.

Dr. Michel is board certified in internal medicine, gastroenterology and hepatology. He is a member of the American Gastroenterology Association, American Society of Gastrointestinal Endoscopy, American Medical Association, American Osteopathic Association, American Osteopathic Board of Internal Medicine, Central Pennsylvania Society for Gastrointestinal Endoscopy, Pennsylvania Society of Gastroenterology and the American College of Gastroenterology.  Dr. Michel is active on the staff at Holy Spirit Hospital and the PinnacleHealth System.

His areas of special interest including inflammatory bowel disease, liver disease and treatment modalities for obscure GI bleeding.

Dr. David S. Mize, MD

Dr. David S. Mize, MD Dr. David Mize received his undergraduate degree from the University of California, Davis, in electrical engineering. He went on to receive a Master of Science degree from the University of California, San Diego, in bioengineering. He received his Doctor of Medicine degree from Hahnemann University School of Medicine and completed his internal medicine residency at Dartmouth-Hitchcock Medical Center in Lebanon, NH. He then served as chief resident of internal medicine at Penn State Milton S. Hershey Medical Center before completing a fellowship in gastroenterology and hepatology there. He joined Jackson Siegelbaum Gastroenterology in 2004.

Dr. Mize is board certified in internal medicine and gastroenterology. He is a member of the American College of Gastroenterology, American Gastroenterology Association, American Society for Gastroenterology, Pennsylvania Society of Gastroenterology and the American College of Physicians.

In his spare time, Dr. Mize enjoys bicycling, skiing and gardening.

Dr. Adnan Ahmad, DO

Dr. Adnan Ahmad, DO Dr. Adnan Ahmad received his undergraduate degree in biology from Rutgers University. He received his Doctor of Medicine degree from the University of Medicine and Dentistry of New Jersey. He completed his internal medicine residency at the University of Connecticut. His gastroenterology and hepatology fellowship was completed at Penn State Milton S. Hershey Medical Center. He joined Jackson Siegelbaum Gastroenterology in 2007.

Dr. Ahmad is board certified in internal medicine, gastroenterology and hepatology. He is a member of the American Gastroenterology Association, American College of Gastroenterology, American Society for Gastrointestinal Endoscopy, Central Pennsylvania Society for Gastrointestinal Endoscopy and Pennsylvania Society of Gastroenterology. He has presented several papers at national medical meetings. He is currently an active staff member of Holy Spirit Hospital and the PinnacleHealth System. His special interests in gastroenterology include inflammatory bowel disease, liver disease, colon cancer and gastroesophageal reflux disease.

Subhra Banerjee, MD

Subhra Banerjee attended medical school in Medical College, Calcutta University, which is one of the premier medical schools in India. After graduating from medical school he moved to the U.S. and completed his internal medicine residency at Wyckoff Heights Medical Center, NY (an academic affiliate of Weill Medical College of Cornell University). During his last year of residency training he was chosen to serve as chief resident for the Department of Medicine. He completed a fellowship in gastroenterology and hepatology at Mount Sinai School of Medicine (Elmhurst Program).  Before moving to the Harrisburg area, he practiced as a gastroenterologist in Shreveport, LA. Dr. Banerjee joined Jackson Siegelbaum Gastroenterology in 2012.

Dr. Banerjee is board certified in internal medicine, gastroenterology and hepatology. He is a member of the American College of Gastroenterology, American College of Physicians, Central Pennsylvania Society for Gastrointestinal Endoscopy and Pennsylvania Society of Gastroenterology. Dr. Banerjee is active on the staff at Holy Spirit Hospital and the PinnacleHealth System.
His areas of special interest include inflammatory bowel disease, liver disease and colon cancer prevention. In his spare time, Dr. Banerjee enjoys travelling, photography and swimming.

Tina M. Navitsky, CRNP

Tina M. Navitsky, CRNP Tina Navitsky, CRNP, received her undergraduate education at York College. She earned her master’s degree in family health at Widener University. She has more than 13 years of nursing experience in intensive care, coronary care, labor and delivery, home health, pediatric oncology and the operating room. She has experience in gastroenterology involving office nursing and endoscopy since 1990.

Ms. Navitsky is board certified as a family nurse practitioner. She is a member of the American Academy of Nurse Practitioners, Central PA Chapter of Nurse Practitioners, PA Gastroenterology Society, American Society of Gastroenterology, American Association for the Study of Liver Disease and Sigma Theta Tau International Society.

Her area of special interest is liver disease, especially hepatitis C. She is a frequent speaker for Merck and Vertex on this topic.

Deborah B. Matisse, MSN, CRNP

Deborah B. Matisse, MSN, CRNP Deborah Matisse, CRNP, graduated summa cum laude from Hartwick College and was recognized as a faculty scholar. She later received her advanced CRNP degree from Widener University in 2005. She is also a certified lactation consultant. She previously worked as a nurse for Mechanicsburg Area School District and Messiah College and later in a drug addiction clinic. The mother of four, she has remained active in the community as a soccer coach and youth group leader.

Lisa Stokes, CRNP

Lisa Stokes, CRNP Lisa Stokes, CRNP, graduated in 1987 with a Bachelor of Science degree in nursing from the University of Pennsylvania. She subsequently received her Master of Science in nursing from the University of Pennsylvania in 1989. She also holds a Bachelor of Fine Arts degree from Kutztown University. She has been a nurse practitioner for 21 years. She previously was employed at Mechanicsburg Family Practice and the Penn State Family Physicians Group in Middletown. She has worked in gastroenterology since 2001.

Ms. Stokes is board certified by the American Nurses Credentialing Center and is a member of Nurse Practitioners of Central Pennsylvania. She has three children and several pets.

Dara (Berninger) Santos, PA-C

Dara (Berninger) Santos, PA-C, graduated in 2003 from Lycoming College with a Bachelor of Science degree in Biology. She furthered her education with a Master of Science degree in Exercise Physiology at Bloomsburg University. She then completed her schooling, earning an additional Master of Science degree in Physician Assistant studies at Lock Haven University.

Ms. (Berninger) Santos is a board-certified physician assistant and a member of the American Gastroenterological Association, Pennsylvania Society of Gastroenterology, American Academy of Physician Assistants, Pennsylvania Society of Physician Assistants and Gastroenterology Physician Assistants.

In her spare time, she enjoys running and playing tennis. She is also a member of the American Council on Exercise and is an ACE-certified personal trainer.