Why is fixation important

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Apply for self-reported educational credits. Figure 1: A paraffin section of kidney that has been fixed using neutral buffered formalin. This is an example of well-fixed tissue showing good nuclear and cytoplasmic morphology with minimal shrinkage showing clearly defined basement membranes and cell margins. Figure 2: A paraffin section of kidney that has been fixed using neutral buffered formalin.

This is an example of poorly-fixed tissue showing inferior nuclear and cytoplasmic morphology with excessive shrinkage and poorly defined cell margins. Note the vacuolation and fragmentation of both nucleus and cytoplasm of cells of the distal tubule and retraction of the glomerulus due to shrinkage.

Types of fixation. Theoretical basis of fixation. Figure 3: A paraffin section of the mucosa of small intestine that has been fixed in neutral buffered formalin, a cross-linking fixative. Nuclear and cytoplasmic preservation is satisfactory but some cellular shrinkage is present. While nuclear preservation is fair there is substantial shrinkage of cytoplasmic and extracellular elements. Compare the morphology demonstrated here with that shown in Figure 3, which was photographed at the same magnification.

Carleton's histological technique. New York: Churchill Livingstone, Introduction to the theory and practice of fixation of tissues. J Histotechnol ; 24 ; Winsor L.

Tissue processing. Most fixation is performed at room temperature, however, increasing temperature will increase speed of fixation whereas lowering temperatures will slow the speed. You will see increased temperatures used in automated processors and microwave processing. Another factor is tissue size. When you gross the tissue, you want to leave adequate space in the cassette. The penetration rate of the fixative can be limited by size. This is why you will see hollow organs bisected open and large specimens bread loafed so that the fixative can more easily penetrate these areas.

You want to aim for a ratio of fixative to tissue. This will allow for enough fixative to adequately bind to the tissue You must also be mindful of the time that the tissue is in the fixative. You want to allow enough time, particularly for the slower non-coagulating fixatives, but it is not recommended to leave in fixatives long-term as they can degrade or overharden. If the pH is not physiologic, ultrastructure and organelle changes will be seen. An indication of this is swelling or shrinking in the mitochondria, which are the first to react to changes in pH.

Fixation on Fixation. Recent Posts See All. Fischer Ed. Fox C. Gustavson K. Academic Press; New York: The Chemistry and Reactivity of Collagen; pp. Fraenkel-Conrat H. Shi S. In: Antigen retrieval techniques: Immunohistochemistry and molecular morphology. Eaton Publishing; Natick, MA: Rait V.

Mason J. Sompuram S. Medawar P. Dempster W. Morales A. Leong A. Pathology Phila ; 18 — Chu W. Titford M. Olert J. Vincek V. Turashvili G. Lykidis D. Nucleic Acids Res. Beckstead J. Wester K. Methods Pathol. Nietner T. Virchows Arch. Paavilainen L.

Kap M. PLoS One. Moelans C. Bostwick D. Mahjoub F. McGhee J. Biochemistry Mosc. Bresters D. Srinivasan M. Williams C. Shibutani M. Cronin M. Chung J. Bussolati G. Nassiri M. BMC Clin. Belloni B. Burns J. Nadji M.

Mitchell D. Jones M. Biological Stain Commission. Kononen J. Ilyas M. Kothmaier H. Nykanen M. Vince D. Braun M. BMC Cancer. Goldmann T. Staff S. Delfour C. Preusser M. Brain Pathol. Gillespie J. Support Center Support Center. External link. Please review our privacy policy. Nietner et al. Mitchell et al. Gillespie et al. Kothmaier et al. Nykanen et al.

Vince et al. Braun et al. Goldmann et al. Delfour et al. Burns et al. Belloni et al. Staff et al.