JCB logo
Avanti Polar Lipids, Inc.
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text (PDF, 1600K)
Right arrow Alert me when this article is cited
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Feder, N.
Right arrow Articles by Sidman, R. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Feder, N.
Right arrow Articles by Sidman, R. L.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?
J. Biophys. and Biochem. Cytol., Vol 4, 593-602, Copyright © 1958 by Rockefeller University Press

ARTICLE

Methods and Principles of Fixation by Freeze-Substitution



Ned Feder M.D.1 and Richard L. Sidman M.D.1

1 From the Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, and the Laboratory of Neuroanatomical Sciences, National Institute of Neurological Diseases and Blindness, National Institutes of Health, Bethesda, Maryland

Freeze-substitution is based on rapid freezing of tissues followed by solution ("substitution") of ice at temperatures well below O°C. A 1 to 3 mm. specimen was thrown into 3:1 propane-isopentane cooled by liquid nitrogen to -175°C. (with precautions). The frozen tissue was placed in substituting fluid at -70°C. for 1 week to dissolve ice slowly without distorting tissue structure. Excess substituting agent was washed out, and the specimen was embedded, sectioned, and stained conventionally.

For best morphological and histochemical preservation, substituting fluids should in general contain both chemical fixing agent and solvent for ice, e.g., 1 per cent solutions of osmium tetroxide in acetone, mercuric chloride in ethanol, and picric acid in ethanol. Preservation of structure was poorer after substitution in solvent alone. Evidence was obtained that the chemical agent fixes tissue at low temperatures. The chemical mechanisms of fixation are probably similar to those operating at room temperature: new chemical cross-linkages, which contain the fixing agent, join tissue constituents together. This process is distinguished from denaturation by pure solvents.

Freeze-substitution has many advantages, particularly the preservation of structure to the limit of resolution with the light microscope, and the accurate localization of many soluble and labile substances.

Submitted on April 30, 1958


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?




  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents