Modified formalin and methanol fixation methods for molecular biological and morphological analyses |
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Authors: | Masayuki Noguchi J Shuichiroh Furuya Tomoyo Takeuchi Setsuo Hirohashi |
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Institution: | Pathology Division, National Cancer Center Research Institute, Tokyo, Japan;Department of Pathology, Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan;Clinical Laboratory Division, National Cancer Center Hospital, Tokyo, Japan |
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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°C and containing 5 mmol/L ethylenediamine-N, N, N', N'-tetraacetic acld (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 clinic pathological laboratory use. |
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Keywords: | EDTA formalin methanol molecular analysis tissue fixation |
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