In addition to neuropathology and histology, Tox Path Specialists is also a fully capable stereology and morphometry laboratory. Where normal morphologic observations are qualitative in nature, stereology and morphometry are quantitative.
What is the difference between morphometry and stereology? In the same way that every square is a rectangle, all stereology is technically morphometry. The difference is that stereology is the analysis of a three-dimensional region of interest using two-dimensional tissue sections. Common stereology measurements include, but are not limited to, region of interest volume (such as the basal forebrain), object of interest quantification (such as number of neurons in the dorsal root ganglia), and average size of an object of interest (such as the average diameter of myelinated nerve fibers in the sural nerve).
Dr. Butt is the author of the chapter, "Practical Stereology in a Preclinical Toxicology Setting" in the upcoming reference book titled Neurostereology, due to be published in 2013.
Below is a brief list of some of the morphometric and stereologic investigations of which TPS is capable.
Myelinated Nerve Fibers: Quantification and size determination of myelinated nerve fibers in nerve cross-sections (tibial, ulnar, sural, etc.). Unmyelianted Nerve Fibers: Quantification of unmyelinated nerve fibers in nerve cross-sections using electron microscopy and image processing.
Neuron investigations: Including the quantification and size measurement of neurons in various regions of interest (ranging from the brain to spinal cord to ganglia). Length determination: Measurements of linear objects of interest (such as nerve fibers). Can be used in place of, or in conjunction with, IENF density investigations. Also commonly used to determine increased or decreased blood vessel growth (angiogenesis) in tumor studies.
Cell/Object of Interest Quantification: Virtually any cell-type/object (glial cells, amyloid plaques, etc.) can be quantified and measured. The volume of areas of interest such as infarcts, ventral horn of the spinal cord and brain regions are best measured stereologically.
One step in the stereologic process: a single counted neuron within a disector frame. Using unbiased sampling, it is possible with stereology to count a relatively small number of an object of interest (usually around 150) and conclude with accurate, meaningful data that, using standard counting, would be impossibly inefficient to come by.