X-Message-Number: 13947 Date: Wed, 14 Jun 2000 10:38:09 -0700 (PDT) From: Doug Skrecky <> Subject: methanol fixation Title Modified formalin and methanol fixation methods for molecular biological and morphological analyses. Source Pathology International. 47(10):685-91, 1997 Oct. Abstract Several simplified fixation methods were examined to determine their suitability for both molecular biological analyses and morphological study. Fixation with 10% v/v formalin alone at 4 degrees C and containing 5 mmol/L ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA) at room temperature preserved significantly more high-molecular-weight DNA than 10% v/v formalin fixation at room temperature. The morphological differences between tissues fixed using these modified formalin fixation methods and conventional 10% v/v formalin fixation were negligible. Of the dehydration fixatives tested, 100% methanol did not cause regional differences due to artificial tissue shrinkage and the morphology of sections prepared by methanol fixation was preserved consistently better than that of acetone- or ethanol-fixed sections. All three dehydration fixatives preserved relatively higher-molecular-weight DNA and RNA, compared with formalin. Cold formalin, formalin containing EDTA at room temperature and 100% methanol are recommended as standard and additional fixatives routine clinicopathological laboratory use. Additional note by poster: Inexpensive technique for mummifying a brain: 1. Purchase silica gel cat litter from a pet store. 2. Purchase methanol antifreeze from a hardware store. 3. Mix silica gel and methanol together in a vat. 4. Place brain in vat. 5. Wait till all water is removed from brain. 6. Remove brain from vat. 7. Let methanol evaporate. (Methanol boils at 64.7 C) Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=13947