Our Providers

Gastroenterologist in Bedford, Derry, and Windham, NH

The brief descriptions below are designed to familiarize you with our staff's training, professional credentials and work experience.


Knut Jon Roalsvig, M.D.

Dr. Roalsvig obtained his M.D. degree from Albert Einstein College of Medicine in New York City.  He pursued his intern and resident training in Internal Medicine at Hartford Hospital in Connecticut.  He completed his Gastrointestinal fellowship training at the University of Connecticut Health Center.  Dr. Roalsvig has been in practice in Southern New Hampshire since 1988.  He founded Granite State Gastrointestinal Consultants in 2002 and is the current Medical Director.

Dr. Roalsvig was born in Norway and grew up in New York State.  He is married to Jean, and has two children.  He has an active interest in hiking, skiing, road cycling and mountaineering, having climbed many peaks, including Kilimanjaro in Africa.

Dr. Roalsvig is Board Certified in Gastroenterology


Christopher N. Dainiak, M.D

Dr. Dainiak is a graduate of Wesleyan University and the University of Connecticut Medical School.  He performed his Internal Medicine residency at Yale University and Fellowship in Gastroenterology at the Norwalk/Yale program.  He has been a clinical gastroenterologist in Southern New Hampshire since 2006.  He has served as Medical Director of Endoscopy and Section Chief of Gastroenterology at Elliot Hospital and on the Medical Executive Committee at Catholic Medical Center.  He specialized in diseases of esophageal motility and performs high resolution manometry.  He is Board Certified in Gastroenterology and a member of A.G.A. and A.S.G.E.

 Dr. Dainiak and his wife Heather are parents to Nicholas and William and the co-founders of the Our Promise to Nicholas Foundation and the Batten Research Alliance (BRA), working at bringing awareness of Batten Disease and facilitating scientific cooperation among family foundations.

Dr. Dainiak is a Master’s level swimmer.  He enjoys train travel, exploring the National Parks and all Boston Sports.


Steven D. Taylor, M.D.

Dr. Taylor earned his M.D. degree from the University of Nevada School of Medicine in 1986.  His fellowship in Gastroenterology was completed at the University of Michigan in 1993.

He also completed a Research Fellowship in Molecular Biology with a National Research Award and has published papers in a range of topics both inside and outside of gastroenterology.

Dr. Taylor has 20 years of clinical experience, primarily in the Reno-Lake Tahoe area.  He relocated to New Hampshire to further his children’s education and live closer to family.  He had been in practice in the N.H. seacoast region prior to joining our practice.

He is a member of the AGA, ACG and ASGE and maintains certification in Internal Medicine and Gastroenterology.

Outside of the practice, he enjoys spending time with his wife Sandy and their two children, as well as participating in a wide range of outdoor activities.


Leon P. McLean, M.D., Ph.D., M.P.H.

Dr. McLean is a graduate of Tufts University School of Medicine, where he earned his M.D. and Master of Public Health degrees, as well as University of Maryland Baltimore, where he earned a Ph.D. in Molecular Medicine.  His post-graduate training was at the University of Maryland School of Medicine where he completed an internship and residency in Internal Medicine as well as a fellowship in Gastroenterology.  Dr. McLean is board certified in Gastroenterology.

Dr. McLean has a special interest and advanced training in the care of patients with inflammatory bowel disease (Crohn’s disease and ulcerative colitis).  He is a member of the American Gastroenterological Association, the American College of Gastroenterology, the American Society for Gastrointestinal Endoscopy, and the Crohn’s and Colitis Foundation of America.

Prior to joining Granite State Gastrointestinal Consultants, Dr. McLean was an Assistant Professor of Medicine at University of Maryland School of Medicine as well as a Staff Physician at the Baltimore VA Medical Center.  He has served as Head of Gastroenterology at University of Maryland Medical Center Midtown Campus and Director of Inflammatory Bowel Disease of the VA Maryland Health Care System.  He has published multiple scientific and clinical articles, co-authored book chapters, and presented his research at several national meetings. Dr. McLean teaches at the Geisel School of Medicine at Dartmouth College, where he is a Clinical Assistant Professor of Medicine.


Robin E. LaBerge, P.A.-C

Robin graduated from UNH at Manchester with a degree in Biological Sciences in 2010.  She earned her Master’s degree in Physician Assistant Studies in 2012 from Massachusetts College of Pharmacy and Health Sciences.  She was born in Bedford, England to active duty military parents.  Robin lived in Guam, located in the South Pacific Ocean, for 3 years.  She joined Granite State GI Consultants in 2013.  Robin loves traveling, laughing, the ocean and crocheting.  She and her husband, a local firefighter, reside in Manchester with their dog, Sheila

Robin is certified by the National Commission on Certification of Physician Assistants (NCCPA).


Samantha Harrington, P.A.-C


Samantha graduated Summa Cum Laude from North Park University with a major in Biology and a minor in Chemistry in 2008. She earned her Master’s degree in Physician Assistant Studies from Massachusetts College of Pharmacy and Health Sciences in 2010. Prior to joining Granite State GI Consultants in 2018, she spent 7 years practicing family medicine. Samantha was born and raised in New Hampshire and her interests include sewing, knitting, and music. She sings on her church’s worship team and dabbles with several instruments including guitar and ukulele. She resides in Merrimack with her rescue dog, Ollie.

Samantha is certified by the National Commission on Certification of Physician Assistants (NCCPA).


Allison Anastasoff, A.P.R.N.

Allison Anastasoff completed her Bachelor of Science in Nursing at Saint Anselm College in 2007. During that time she worked as a nurse in the Intensive Care Unit, Cardiovascular Operating Room, and was a Research Coordinator. She earned her Master of Science in Nursing at the University of New Hampshire. She spent 2 years practicing family medicine prior to joining Granite State GI Consultants in 2019. Allison enjoys spending time with family and friends, traveling, and cooking. She and her husband reside in Auburn with their rescue dog, Bella.

Allison holds a national certification with the American Association of Nurse Practitioners (AANP).