Kumarasinghe M P, Constantine S R, Hemamali R L
Department of Pathology, Faculty of Medicine, University of Colombo, Sri Lanka.
Malays J Pathol. 1997 Dec;19(2):137-40.
Ninety-five percent (95%) ethanol is the standard cytological fixative used in many laboratories. Commercially available ethanol is expensive and not freely available in some institutions. Methanol, a tissue dehydrant, is also known to be a cytological fixative. However its efficacy has not been assessed or documented in the literature. One hundred and eight consecutive fine needle aspiration biopsies (FNAB) of thyroid performed at the Department of Pathology, Faculty of Medicine, Colombo were included in a study to assess the efficacy of methanol as a cytological fixative. Aspirated material was smeared on at least 2 slides, one fixed in ethanol and the other in methanol, and stained with haematoxylin and eosin (H&E). The 2 smears were separately assessed for preservation of colloid and cells (nuclei and cytoplasm), as determined by the staining quality with the H&E stain. A score was given for each smear and the final scores for ethanol and methanol were statistically compared. The evaporation rates for ethanol and methanol were calculated. The total score for preservation of colloid was 294/300 (98%) for methanol and 291/300 (97%) for ethanol (p = 0.4). The total score for preservation of cells (nuclear and cytoplasmic) was 276/279 (98.9%) for methanol and 274/279 (98.2%) for ethanol (p = 0.7). The evaporation rates per 100 ml when the bottles used for fixation were kept closed and open per 24 hours were 1 and 37 for methanol and 0 and 17 for ethanol. Literature search did not show inhalational side effects of methanol in humans under standard laboratory conditions. We conclude that methanol is as effective as ethanol for fixation of smears and cheaper.
95%乙醇是许多实验室使用的标准细胞学固定剂。市售乙醇价格昂贵，在一些机构中无法自由获取。甲醇作为一种组织脱水剂，也被认为是一种细胞学固定剂。然而，其效果尚未在文献中得到评估或记录。科伦坡医学院病理科连续进行的108例甲状腺细针穿刺活检（FNAB）被纳入一项研究，以评估甲醇作为细胞学固定剂的效果。将吸出的材料涂抹在至少2张载玻片上，一张用乙醇固定，另一张用甲醇固定，并用苏木精和伊红（H&E）染色。分别评估这两张涂片的胶体和细胞（细胞核和细胞质）保存情况，这通过H&E染色的质量来确定。为每张涂片给出一个分数，并对乙醇和甲醇的最终分数进行统计学比较。计算乙醇和甲醇的蒸发速率。甲醇保存胶体的总分数为294/300（98%），乙醇为291/300（97%）（p = 0.4）。甲醇保存细胞（细胞核和细胞质）的总分数为276/279（98.9%），乙醇为274/279（98.2%）（p = 0.7）。当用于固定的瓶子每24小时保持关闭和打开时，甲醇每100 ml的蒸发速率分别为1和37，乙醇为0和17。文献检索未显示在标准实验室条件下甲醇对人体有吸入性副作用。我们得出结论，甲醇在涂片固定方面与乙醇同样有效且更便宜。
