Dr. Farhad Ismail-Beigi earned his degree in medicine from Vanderbilt University School of Medicine.  He completed his medical training with a residency at Vanderbilt University Hospital and the University of Washington, where he also trained as a fellow in the specialty of gastroenterology. 

After completing his specialty training Dr. Ismail-Beigi served as a Major in the U.S. Army and was Chief of Gastroenterology Service at Womack Army Hospital in Fort Bragg, North Carolina.  In 1972 he joined Dr. Lee Hershenson and his father in private practice forming Gastroenterology Associates, Inc.  Dr. Ismail-Beigi was instrumental in instituting a fellowship training program in the specialty of  gastroenterology at Shadyside Hospital and is very involved with the teaching activities of the medical interns, residents, and fellows at the University of Pittsburgh Medical School.  He has been the Chief of the Division of Gastroenterology at UPMC Presbyterian Shadyside Hospital-Shadyside Campus since 1990.

Dr. Ismail-Beigi is board-certified in gastroenterology and internal medicine. He is a member of the American Gastroenterological Association, Alpha Omega Alpha, American College of Physicians, American Society for Gastrointestinal Endoscopy, Pennsylvania Society of Gastroenterology, Pittsburgh Gut Club and Western PA Endoscopic Society, and the Crohn’s and Colitis Foundation of America. In 1994, Dr. Ismail-Beigi was awarded the “Physician of the Year” by the Greater Pittsburgh Chapter of the Crohn’s and Colitis Foundation of America.

Dr. Ismail-Beigi practices at UPMC Presbyterian Shadyside Hospital, WPAH-Forbes Regional Health Center, and the Digestive Health and Endoscopy Center.

His private office practice is located at Gastroenterology Associates, Inc. in Shadyside and a second location in the Penn Hills.

Michael F. Ennis, M.D.
Dr. Michael Ennis earned his degree in medicine from University of Pittsburgh School of Medicine.  He completed both his residency and fellowship training in the specialty of  gastroenterology at the University Health Center of Pittsburgh in Pennsylvania.  Prior to entering medical school, Dr. Ennis worked on a Navajo Indian Reservation while doing a Clinical Preceptorship.  In 1978, he joined Dr. Lee Hershenson and Dr. Farhad Ismail-Beigi in the private practice at Gastroenterology Associates, Inc. 

Dr. Ennis is board-certified in gastroenterology and internal medicine. He is a Clinical Assistant Professor of Medicine for the University of Pittsburgh School of Medicine and is a member of the American Gastroenterological Association, Allegheny County and Pennsylvania State Medical Societies, PA Society of Gastroenterology, American College of Physicians, Pittsburgh Gut Club, Western Pennsylvania Endoscopic Society, and the Crohn’s and Colitis Foundation of America.  He has served as Editorial consultant for Digestive Disease and Sciences and Consultant in Gastroenterology for Pennsylvania Blue Cross and Blue Shield.  In 1991-92 he was President of the Medical Staff at Shadyside Hospital.  Dr. Ennis also was Chief of the Division of Gastroenterology at Forbes Regional Health Center in 1984-88 and again 1999-2002.  He has researched and published clinical articles on digestive health diseases.

Dr. Ennis practices at UPMC Presbyterian Shadyside Hospital, WPAH-Forbes Regional Health Center, and Digestive Health and Endoscopy Center, Inc. His office practice is based in the Penn Hills area of Pittsburgh with a second location in the Shadyside area of Pittsburgh.

Dr. M. Samir Ayasso earned his degree in medicine from Damascus University Medical School located in Syria.  After several years of private clinical practice in Syria, Dr. Ayasso came to the United States where he applied for the residency program at Shadyside Hospital that brought him to Pittsburgh.  After completing his residency he continued his training with a specialty fellowship in gastroenterology at Shadyside Hospital.  Upon completion of his medical specialty training Dr. Ayasso joined Gastroenterology Associates, Inc.

Dr. Ayasso is board-certified in the specialty of gastroenterology and internal medicine.  He is a Clinical Assistant Professor of Medicine for UPMC Presbyterian Shadyside Hospital and he is a member of the American Society of Gastrointestinal Endoscopy, American Gastroenterological Association, American College of Gastroenterology, Pittsburgh Gut Club and Western PA Endoscopic Society, and the Crohn’s and Colitis Foundation of America.

Dr. Ayasso practices at UPMC Presbyterian Shadyside Hospital, WPAH-Forbes Regional Health Center, Monsour Medical Center, and the Digestive Health and Endoscopy Center, Inc. His office practice  Gastroenterology Associates, Inc. with locations in the Shadyside area of Pittsburgh, PA, a second location in the Penn Hills area of Pittsburgh, PA and a third location in Harrison Township, PA.

Dr. Ayasso’s practice is dedicated to gastrointestinal diseases with special interest in hepatobiliary diseases.

Dr. Hitendra R. Patel earned his doctor of medicine degree from Baroda Medical College, The M.S. University and S.S. General Hospital located in Baroda, India.  His residency training in Internal Medicine was completed at North Middlesex Hospital in London and Benenden Hospital Benenden in Kent.  After completing his training in London, Dr. Patel came to the United States and began a Clinical Research Fellowship in Endocrinology at Shadyside Hospital. He then furthered his education by completing a Fellowship in Gastroenterology also at Shadyside Hospital.  His specialization in gastroenterology continued with a private practice for several years in Ohio, then he returned to Pittsburgh and joined the specialists at Gastroenterology Associates, Inc.

Dr. Patel has presented and published articles and abstracts relating to the practice of Endocrinology and Gastroenterology.  He was recipient of the “Resident of the graduating class of 1995” at Shadyside Hospital and awarded “The Golden Apple Award” for excellence in teaching at Forbes Regional Hospital Family Practice residency.  He is very active in the teaching of interns, residents, and fellows with UPMC Presbyterian-Shadyside Hospital Campus and the University of Pittsburgh.

Dr. Patel is board-certified in Gastroenterology and Internal Medicine.  He is a member of the American Society of Gastrointestinal Endoscopy, the American Gastroenterological Association, and the Crohn’s and Colitis Foundation of America.

Dr. Patel practices at UPMC Presbyterian Shadyside Hospital, WPAH-Forbes Regional Health Center and the Digestive Health and Endoscopy Center, Inc. in Pittsburgh, PA.  His clinical practice is located at the UPMC Shadyside Medical Building and at Integrity Suites in Penn Hills.

Dr. Tina Musahl earned her medical degree from the Medical University of South Carolina in Charleston . She completed her residency in internal medicine at the Medical College of Virginia and recently finished her clinical fellowship in gastroenterology, hepatology and nutrition at the University of Pittsburgh Medical Center. After completing her specialty training in gastroenterology she joined Gastroenterology Associates in private practice.

Dr. Musahl is board-certified in the specialty of gastroenterology and internal medicine. She is a member of the American Gastroenterological Association, American College of Gastroenterology, American Society for Gastrointestinal Endoscopy, Pittsburgh GUT Club, Western Pennsylvania Endoscopic Society, and the Crohn's and Colitis Foundation of America.

Dr. Musahl has been involved with numerous research studies and published papers and abstracts on various gastroenterology and internal medicine topics. She continues to participate in teaching activities of the interns, residents and fellows at the UPMC Presbyterian Shadyside Hospital .

Dr. Musahl practices at UPMC Presbyterian Shadyside Hospital , WPAH-Forbes Regional Hospital , and at the Digestive Health and Endoscopy Center, Inc. Her office practice is located in the Shadyside area of Pittsburgh with a second location in the Penn Hills area.

Ms. Kristen Zon is a native of Beaver County and has always wanted to pursue a career in health care.  She graduated cum laude from Slippery Rock University in 2002 where she received her Bachelor of Science degree in Biology.  While in school, Ms. Zon was a member of Phi Eta Sigma; Golden Key National Honor Society; and the Biological Honor Society, Tri-Beta.

Ms. Zon graduated from Chatham College in 2004 where she received her Master’s Degree in Physician Assistant studies.  She recently joined Gastroenterology Associates, Inc. and is excited to begin practicing medicine.  She is NCCPA certified and is a member of the Pennsylvania Society of Physician Assistants.

Currently, Ms. Zon practices full-time at Gastroenterology Associates, Inc. and has active staff privileges at UPMC Presbyterian Shadyside Hospital and WPAHS-Forbes Regional Hospital.  Her private practice is based at Gastroenterology Associates, Inc. located in Shadyside, PA.

Ms. Bigante was hired by the practice in January 1980, as the insurance billing assistant. When she was hired, the practice consisted of 3 doctors, one office, and a staff of four. Ms. Bigante was promoted to manage the office 3 years later. Over the years she has assisted the physicians with the recruitment of Dr. Samir Ayasso, Dr. Hitendra Patel, and more recently, Dr. Tina Musahl. Ms. Bigante has gained experience and knowledge of the management of subspecialty practice over the last 22 years. She cites the most challenging and rewarding part of her career with the organization however, was helping the physicians develop the Digestive Health and Endoscopy Center, Inc., a state-of-the-art, PA state licensed, Medicare certified, and accredited ambulatory endoscopy center, located in the Penn Hills area of Pittsburgh, PA. With the adoption of the endoscopy center and a second full-time office in Penn Hills, Ms. Bigante has seen her staff grow to 30 employees.

Ms. Bigante has acquired a certificate degree in Human Resource Management from the University of Pittsburgh, School of General Studies, as well as a certificate degree in Medical Practice Management from Robert Morris University. She is professionally affiliated with PAMGMA (Pennsylvania Medical Group Management Association) and AGA (American Gastroenterological Association).