DEVELOPMENT OF RAPID FIXATION METHODS FOR NEURAL TISSUE.
Final technical rept. 1 Apr 66-30 Apr 67,
IIT RESEARCH INST CHICAGO ILL
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The objective of this program was to develop methods for rapid fixation and preservation of central nervous system tissue. During the first phase of work a perfusion system was developed which would optimally preserve brain tissue with chemical fixatives. Various fixatives were tested and glutaldehyde was found to be the preservative of choice. It penetrated rapidly and maintained structural detail. In order to evaluate the efficiency of the fixative system, histochemical, white light microscopic and isoenzyme evaluations were done. Some reduction in histochemical activity was noted, while white light microscopy indicated good preservation of cellular detail. Isoenzyme evaluations indicated up to 90 loss of activity with chemical fixatives. A system was developed which would freeze brain tissue rapidly for biochemical analyses. Accordingly, a cryogenic probe was designed and constructed which will rapidly remove a plug of brain tissue and freeze it to liquid nitrogen temperature -190C. This instrument can be operated remotely and will remove and freeze a piece of brain tissue in less than 5 sec. Histochemical and isoenzyme assay of frozen tissue plugs indicate optimal enzyme preservation. Author