X-Message-Number: 4997
Date: Mon, 16 Oct 1995 05:23:44 -0700 (PDT)
From: Doug Skrecky <>
Subject: request for help answered

 Suggestion #1: Don't bother with methanol fixation. If additional
 fixation is desired the fastest method for acheiving this in a large
 block of tissue is to use a cold microwave irradiation procedure. (See
 "Rapid Cold Fixation of Tissue Samples by Microwave Irradiation for Use
 in Electron Microscopy" Histochemical Journal 719-725 Vol.25 1993)

 Suggestion #2: The fastest way to obtain a high percentage concentration
 of cryoprotectant is to dehydrate the tissue. Use an anhydrous
 cryoprotectant solution (ethylene glycol?) loaded with silica gel bead
 desiccant. The following are the tissue permeabilites relative to
 glycerol. (See The Journal of General Physiology 714-736 Vol.62 1973)
                      glycerol 1.0
                      DMSO 2.2
                      propylene glycol 3.0
                      ethylene glycol 5.8
                      ethanol 15.1
                      methanol 19.6
                      dimethyl formamide 20.5
             triethylene glycol diacetate 44.1
                      water 1577.6

 Suggestion #3: Keep the brain refrigerated. DNA deterioration in
 formaldehyde treated tissue is dramatically slowed at 4 C as opposed to
 room temperature. High pH, microwave irradiation and salt also inhibited
 deterioration. (Path Res. Pract. 66-72 Vol.189 1993)


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