What is it about?

A numerical scoring system is presented, for evaluating fixation of rodent brain and kidney for subsequent light microscopy of paraffin sections. Results are presented for 15 fixative mixtures, and discussed in relation to earlier published comparisons.

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Why is it important?

Other investigators, notably J.R. Baker, have attributed "grades" from I to V to various fixatives, but without exactly defining the criteria of structural preservation for the different grades. With the new numerical system, the criteria to look for in the sections are defined and illustrated. Brain and kidney are two tissues in which fixation artifacts are commonly seen and easy to evaluate.


Manfred Gabe (1916-1973), was a French zoologist and the author of an 1106-page book posthumously published in 1976: "Histological Techniques" (translated by R.E. Blackith), ISBN 225441545 (Masson, Paris), ISBN 0397901620 (Springer. New York), ISBN 3540901620 (Springer, Berlin). Gabe evaluated fixatives for their fidelity of "micro-anatomical" and "cytological" immobilization of the structures of tissue and cells. Good micro-anatomical fixation minimizes differential shrinkage during fixation and subsequent dehydration and embedding in paraffin. Good cytological fixation preserves the integrity of easily disrupted cells (such as erythrocytes) and keeps nuclear chromatin and cytoplasmic organelles in their places within cells. My scoring system provides for separate numerical evaluations of microanatomical and cytological fixation. The scheme may seve as a guide for fixation of other solid organs, but it may not be appropriate for specimens largely composed of air (lung) or water (plants).

Dr John A Kiernan
Western University

Read the Original

This page is a summary of: A system for quantitative evaluation of fixatives for light microscopy using paraffin sections of kidney and brain, Biotechnic & Histochemistry, January 2009, Taylor & Francis,
DOI: 10.1080/10520290802646619.
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