American College of Toxicology

About ACT
Meetings & Courses
Good Stuff

= Members Only

Educational Courses

Pathology for Nonpathologists
Speaker Biographies

Ted Alan Birkebak, PhD, DVM, DACVP

Dr. Ted Birkebak is a pathologist, manager at Experimental Pathology Laboratories, Inc. (EPL). In the pharmaceutical industry, he has functioned as a study pathologist, study director, project team toxicologist, and a manager of both toxicology and pathology groups. He has worked on programs from discovery thru post-NDA life cycle management and has experience interacting with US and EU regulatory agencies. Following veterinary training at the University of Florida and a combined PhD program/pathology residency at Washington State University, Dr. Birkebak spent five years at the University of Washington in Seattle as a postdoctoral fellow and Assistant Professor supporting research and diagnostic activities in the primate center and rodent facility. In 1999, he joined Pharmacia & Upjohn (now Pfizer) where he served as a study pathologist, study director and project team toxicologist. In 2006, he joined Sanofi Aventis (now Sanofi) where he initially supported pathology and toxicology functions, and then became Head of Pathology at the US site in Bridgewater, NJ. In 2015, he joined EPL in Redwood City, CA.


Dr. Bolon earned BS (1983), DVM (1986), and MS (1986) degrees in six years at the University of Missouri, “enjoyed” an anatomic pathology residency (1986–1989) at the University of Florida, and obtained a PhD (1993) from Duke University while completing postdoctoral training at the Chemical Industry Institute of Toxicology (1989–1993). He was employed by Pathology Associates International as associate director of the Molecular and Immunopathology Division (Frederick, MD; 1993–1994) and later as staff pathologist at the National Center for Toxicological Research (Jefferson, AR; 1994–1996) before moving to Wyeth-Ayerst Research (Plainsboro, NJ; 1996–1997) as a senior scientist. Dr. Bolon served as an experimental pathologist at Amgen (Thousand Oaks, CA; 1997–2004) responsible for evaluating engineered rodents and the efficacy of novel biopharmaceuticals. He subsequently founded an experimental pathology consulting practice (GEMpath, for “Genetically Engineered Mouse Pathology”), working there from 2004–2011 in southwestern Utah and later Longmont, CO. Dr. Bolon worked for a time as an associate professor at The Ohio State University College of Veterinary Medicine (Columbus, OH; 2011–2015), after which he returned to Longmont, CO to relaunch GEMpath (2015 to date). Brad is a Diplomate of both the American College of Veterinary Pathologists (ACVP, anatomic pathology; 1991) and American Board of Toxicology (ABT; 1996, recertified 2001, 2006, 2011, 2016) and is a Fellow of both the Academy of Toxicological Sciences (ATS; 2011) and the International Academy of Toxicologic Pathology (IATP; 2007). He has written or co-authored over 200 articles and book chapters, has edited or co-edited four books, and is a frequent invited speaker at national and international meetings on mouse pathology (especially in genetically engineered and developing animals) and toxicologic neuropathology.

Mark T. Butt, DVM, Diplomate, ACVP

Dr. Mark Butt received his Doctorate of Veterinary Medicine and anatomic pathology training at Cornell University. His professional career as a toxicologic neuropathologist spans more than 25 years. In July 2007, Dr. Butt founded Tox Path Specialists, a company providing consulting, neuropathology and neurohistology support to preclinical studies and other investigational endeavors. He has evaluated well over 1,000 studies involving the assessment of the nervous system in preclinical safety or efficacy studies, including many studies utilizing direct delivery to the central and peripheral nervous systems. Dr. Butt is the co-editor and contributing author for the reference book, Neuropathology for Pathologists and Toxicologists, published by J. Wiley and Sons, and the author/co-author of numerous other book chapters and scientific manuscripts pertinent to the pathology of the nervous system.

Ellen Williams Evans, PhD, DVM, DACVP

Dr. Evans currently serves as global head of Pfizer’s Immunotoxicology Center of Emphasis. She has a BA in Modern Languages (magna cum laude) from the College of William and Mary in Virginia and Doctor of Veterinary Medicine from Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech. After five years of companion animal private clinical practice, she obtained a PhD in Immunology and completed a residency in clinical pathology at the University of Georgia College of Veterinary Medicine. She is board certified in clinical pathology by the American College of Veterinary Pathologists. After completing her PhD and residency, Dr. Evans was on the faculty of the University of Wisconsin School of Veterinary Medicine and subsequently joined Schering-Plough Research Institute, providing clinical pathology expertise, overseeing the clinical pathology laboratory, and taking on increasing responsibilities as head of comparative medicine and establishing and managing an immunotoxicology laboratory. She also worked with drug development teams to resolve issues and develop regulatory strategies related to immunotoxicology and immunomodulation. She joined Pfizer in June of 2010. Dr. Evans has been a member of the HESI Immunotoxicology Technical Committee since 1997 and served as its chair or co-chair for over 10 years.

Kendall S. Frazier, DVM, PhD, DACVP, DABT

Dr. Ken Frazier is a director of pathology and senior science fellow at GlaxoSmithKline (GSK) where he has been for over 15 years. His primary duties at GSK involve acting as a toxicologic study pathologist and as a scientific consultant for drug development projects, and he is a member of the Nephrology Safety Panel. Current scientific interests involve mechanisms of drug-induced toxic responses in the urinary system. He holds a BS in biology from Wichita State University, a DVM from Kansas State College of Veterinary Medicine and a PhD in molecular biology from the University of Miami. He completed a residency in comparative pathology at University of Miami's School of Medicine and is board certified in both Pathology and Toxicology. Dr. Frazier has previously held academic appointments at the University of Georgia School of Veterinary Medicine, where he focused on rodent models of kidney failure and mechanisms of toxic and infectious renal disease. He has authored over 75 scientific journal publications and book chapters. He chaired the Urinary System subcommittee for the Society of Toxicologic Pathology's (STP) INHAND initiative, and has chaired many other committees and meetings for the STP, the American College of Veterinary Pathologists (ACVP) and other organizations. He has been on the editorial board for multiple scientific journals, and is also a fellow of the International Academy of Toxicologic Pathology.

Marlon Rebelatto, DVM, PhD, DACVP

Dr. Rebelatto received his Doctor in Veterinary Medicine degree in Brazil, a Master’s in Epidemiology and Public Health and a PhD in Immunology at Purdue University. He then completed a residency in Pathology at Purdue University and is a Diplomat of the American College of Veterinary Pathologists. Marlon worked for seven years at MPI Research, evaluating pathology in a wide variety of toxicity studies and served as Director of Immunotoxicology. In 2009, Marlon joined MedImmune (a member of the AstraZeneca group) where he collaborates in many aspects of drug development, including target identification and validation, preclinical and clinical trial biomarker development and assessment, and companion diagnostics development. He has coauthored several papers and book chapters, has filed patents, and presented extensively in the use of tissue-based biomarkers in preclinical and clinical trials, and on the pathology of the immune system.

Shannon R. Roff, MS, DVM, PhD, DACVP

Shannon Roff is a Veterinary Pathologist in the Safety Assessment/Immunopathology department at Charles River Laboratories in Frederick, Maryland. Prior to her appointment at CRL, she completed a combined Anatomic Pathology residency and PhD in the Department of Infectious Diseases and Pathology at the University of Florida College of Veterinary Medicine. Her PhD work focused on the development of a T cellbased HIV vaccine using FIV/cats as an animal model. Prior to her time at the University of Florida, Shannon held several research positions at academic, government, and corporate institutions where she worked on various translational projects including models of drug addiction, toxicology and safety assessment, gene therapy, and antibody-based targeted cancer therapeutics.

Bhanu Pratap Singh, MS, BVSc, DACVP, DABT

Dr. Bhanu Singh is currently working as Scientific Director, Pathology at Drug Discovery Sciences in Janssen Research & Development LLC (Johnson & Johnson Pharmaceuticals, USA). In his role, Dr. Singh supports drug discovery and development by providing scientific leadership in the design and conduct of toxicology experiments that focus on characterization and safety of novel therapeutic targets and/or understanding potential mode of action for toxicity in preclinical studies. Prior to joining Johnson & Johnson Pharmaceuticals R&D in early 2012, he worked at the DuPont Haskell Global Centers for Health and Environmental Sciences (Newark, DE), where he spent more than three years in the position of Senior Research Pathologist. Dr. Singh has a strong scientific interest in drug discovery (oncology and Cardiovascular metabolism), molecular Pathology, liver toxicity, development of animal models of human diseases, and chemical carcinogenesis.

He has authored over twenty peer reviewed publications, five book chapters, 80+ regulatory and research pathology reports, and delivered more than 70 presentations in various scientific meetings. He is a diplomate of American College of Veterinary Pathologist (DACVP) and American board of Toxicology (DABT). He is also a fellow of International Academy of Toxicologic pathology (IATP). Dr. Singh is actively involved in professional activities for various Societies of toxicology and pathology including Chair for STP Education Course Committee and in the past served as Associate Editor for Drug and Chemical Toxicology, Chair for IFSTP-IATP Webinar Committee, and Chair for Dog INHAND Committee. Dr. Singh completed his pathology residency training at The Royal Veterinary College, London (UK). During his residency training, he did internships and externships at Bern University (Switzerland), University of California Davis (USA), Armed Force Institute of Pathology (Washington DC), and National Institute of Environmental Health Sciences (NIEHS). After finishing residency, he worked at NTP/NIEHS (RTP, NC) as visiting fellow in Dr. Dave Malarkey's Laboratory. He received his veterinary training at G B Pant University (Pantnagar, India) and a Master's at Utrecht University (the Netherlands).

Justin D. Vidal, DVM, PhD, DACVP

Dr. Vidal is a Scientific Advisor, Pathology and DART at MPI Research with more than 15 years of industry experience. He is an internationally recognized expert in male and female reproductive toxicologic pathology and provides both consultancy services and specialized pathology support. Prior to joining MPI Research, Dr. Vidal was a Senior Pathologist at Vet Path Services, Inc. providing routine pathology support for a variety of sponsors and CROs as well as consultancy services on the male and female reproductive systems. Dr. Vidal spent over 10 years at GlaxoSmithKline, where he began as a pathologist and drug development project team member and finished as Head of Pathology. He received his DVM from the Virginia-Maryland Regional College of Veterinary Medicine in 1999 and his PhD in reproductive physiology/toxicology from the University of California, Davis in 2004. He is a regularly invited speaker on the male and female reproductive systems at conferences and workshops around the world. He has over 20 peer reviewed publications including INHAND (female reproductive system), book chapters, and special issues on reproductive pathology.

Join or Renew ACT membership
11190 Sunrise Valley Drive, Suite 300, Reston, Virginia 20191
Tel: 703.547.0875 | Fax: 703.438.3113 | Email:

Copyright © 2019 American College of Toxicology. All rights reserved.
You may view the ACT Privacy Policy, provide consent to ACT to email you communications, or unsubscribe to stop receiving further ACT communication. Privacy Policy | Provide Consent | Unsubscribe