John P. McLaughlin, D.O, F.A.C.G., F.A.C.P.
... established Harrisburg Gastroenterology, Ltd.
in 1978. He completed his Internship, Residency,
and Fellowship at the Cleveland Clinic in Cleveland,
Ohio. Currently he is the Chief of Gastroenterology
at Pinnacle Health Hospitals.

Dr. McLaughlin is Board Certified in Internal
Medicine and Gastroenterology. He is a Fellow in
both the American College of Physicians and the
American College of Gastroenterology. Dr. McLaughlin
is an active staff member at Pinnacle Health Hospitals
including Harrisburg Hospital and Community General.
He is also on the staff at Holy Spirit Hospital, Triumph,
Select Medical, and HealthSouth.

He serves on many hospital committees and is a consultant for several insurance companies in the area. He is the Medical Director and co-owner of Harrisburg Endoscopy & Surgery Center, Inc.
Kevin C. Westra, D.O.,
... a partner in the practice, has been with Harrisburg Gastroenterology, Ltd. since 1996. After his Internship at Memorial Hospital in York, Pennsylvania, he completed his Residency and Fellowship at Shadyside Hospital in Pittsburgh, Pennsylvania.

Dr. Westra is an active staff member at all of the Pinnacle Health Hospitals, Holy Spirit Hospital, HealthSouth, Triumph, Select Medical, and HealthSouth.

Dr. Westra is Board Certified in Internal Medicine and Gastroenterology. He is a co-owner of Harrisburg Endoscopy & Surgery Center. At the facility he serves on the Quality Assurance Committee and Governing Board.
Mark C. Friedman, M.D.
... has been in practice in Central Pennsylvania since 1978. He completed his Internship and Residency at the Bronx Municipal Hospital Center. His Fellowship was completed at the Washington Hospital Center in Washington, D.C.

He is an Associate Clinical Professor of Medicine at the Milton S. Hershey Medical Center. Dr. Friedman is Board Certified in Internal Medicine and Gastroenterology. He is also on the staff at all of the Pinnacle Health Hospitals, Holy Spirit Hospital, Triumph, Select Medical, HealthSouth, and Harrisburg Endoscopy & Surgery Center.
Michael A. Veliuona, M.D.
... joined the practice in July, 2006. He completed his Internship, Residency, and Fellowship at The Pennsylvania State University Hershey Medical Center.

He served as the Chief Fellow in the Division of Gastroenterology and Hepatology at the Pennsylvania State University in 2005-2006. He is on the staff at all of the Pinnacle Health Hospitals, Holy Spirit Hospital, Triumph, Select Medical, HealthSouth, and Harrisburg Endoscopy & Surgery Center. Dr. Veliuona is Board Certified in Interal Medicine and Gastroenterology.
Nicholas A. Katzen, M.D.

... received his medical degree from University of the Witwatersand in Johannesburg, South Africa. His internship was at Faulkner Hospital in Boston, MA and his fellowship was at Shadyside Hospital in Pittsburgh, PA.

Dr. Katzen is Board Certified in Gastroenterology.

Nicholas A. Mahoney, M.D.

... received his medical degree from Jefferson Medical College in Philadelphia, PA. His internship and fellowship were at the University of Pittsburgh Medical Center in Pittsburgh, PA.

Dr. Mahoney is Board Certified in internal medicine. Harrisburg Gastroenterology LTD. welcomes him to practice effective July 28th, 2014.

Michelle R. Lamb, PA-C
... is a licensed Physicians Assistant. She received her Masters Degree in Physicians Assistant Sciences from St. Francis University.

She is a member of the American Academy of Physicians Assistants and the Pennsylvania Society of Physicians Assistants. Michelle is on staff at all of the Pinnacle Health Hospitals, Holy Spirit, Triumph, Select Medical, and HealthSouth.
Linda Woodin, CRNP,

... is a Certified Registered Nurse Practitioner. She received her Masters Degree in Nursing from the University of Pennsylvania School of Nursing and a Certificate from the Family Nurse Practitioner Program from the Pennsylvania State University.

She is also on staff at Pinnacle Health Hospitals, Holy Spirit, Triumph, Select Medical, and HealthSouth.

Lisa C. Brenize, MSPAS, PA-C,

... is a licensed, board certified physician assistant.  She received her Masters Degree in Physician Assistant Studies from DeSales University.  She acquired additional experience in Gastroenterology and Hepatology from Penn State Hershey Medical Center. 






Harrisburg Gastroenterology, Ltd. • 4760 Union Deposit Road, Suite 100, Harrisburg, PA 17111
(p) 717.
545.9811 • (f) 717.545.1873
© 2006 Harrisburg Gastroenterology, Ltd. All Rights Reserved / ©Stephen Moyer Photography