Welcome to Tox Path Specialists, LLC.
​Tox Path Specialists, LLC (TPS) is a fully GLP compliant provider of neuropathology evaluations and consultations. Company President and Founder, Dr. Mark T. Butt, consults with numerous global pharmaceutical and pathology companies. He is co-author/co-editor of Fundamental Neuropathology for Pathologists and Toxicologists: Principles and Techniques (J. Wiley and Sons, publisher) and the principal investigator/study neuropathologist for over 500 preclinical investigations.

Dr. Butt has over 20 years experience specializing in the evaluation of the adult and developing nervous system, as those investigations are pertinent to the development of actual or potential neuroactive molecules, biologics, and devices. For his expertise in neuropathology he is a frequent speaker at national/international meetings, educational symposiums, and FDA sponsored events. Dr. Butt is a regulatory consultant on matters concerning the nervous system, and the proximity of TPS to the main offices of the Food and Drug Administration means assistance is readily available not only over the phone, but in person if needed. 

The laboratory at TPS provides a wide range of neurohistology services: frozenparaffin and resin embedded sections, numerous special stains, and a range of morphometric/stereologic services. Glial and neuronal immunohistochemical markers, stains to detect neuronal necrosis, and specialized trimming for tissues/specimens not typically harvested in the course of a preclinical study are all specialties of TPS, including preparation and evaluation of nervous system tissues for developmental neurotoxicity studies.

Under the direction of Dr. Butt, morphometric and stereologic investigations of the brain, spinal cord, peripheral nerves and dorsal root/sympathetic ganglia are all possible and coordinated into a larger anatomic pathology effort.
Phone: 301-378-0505

Email: mbutt@toxpath.net

Special Stains and Immunohistochemistry
Neuronal Toxicity
Paraffin Histology
Resin Embedding