Practical approaches to stereology in the setting of aging- and disease-related brain banks

The unbiased sampling techniques of stereology have been developed to avoid the inaccuracies of using 'representative' sections for morphometric studi es. In order to carry out a stereologically valid study, the region of inte rest must be fully available for sampling and its boundaries or its constit uents must also be distinctly identifiable. However, in the setting of a br ain bank in which only one half of the brain specimen is fixed for morpholo gy, a logistic problem arises in satisfying the needs of the diagnostic neu ropathologist with that of the stereologically oriented morphologist. We pr esent a dissection approach in which the region for analysis must be used f or unbiased sampling and also be available for paraffin-embedded neuropatho logic work-up. Following fixation, a block consisting of the entire region of interest is removed intact and using a multibladed knife the block is su bsectioned in the coronal plane at regular intervals. Alternate blocks are chosen for either paraffin embedding and destined to neuropathologic evalua tion or are processed for stereology. The stereology blocks can be either c ryoprotected or placed in phosphate buffer and are serially sectioned on a cryostat or a Vibratome. Preliminary analyses using this approach have prov ided reliable estimates of the total number of different neuronal populatio ns and disease-related lesions in a variety of human and non-human banked s pecimens. In addition, this approach has definite advantages in that it pro vides rigorous quantitative estimates of neuropathologic changes that can b e correlated to clinical data and does not compromise the routine neuropath ological diagnostic procedure of the materials. (C) 2000 Elsevier Science B .V. All rights reserved.