WILLIAMS R C, KALLMAN F
J Biophys Biochem Cytol. 1955 Jul 25;1(4):301-14. doi: 10.1083/jcb.1.4.301.
A method of securing serial sections for electron microscopy is described. Serial sections present certain anomalies of interpretation of a nature such that a complete and detailed three-dimensional reconstruction of the sectioned tissue cannot be made. These anomalies are discussed, as well as those which have been encountered in the interpretation of single sections. Observations of the following kinds have been made in an attempt to elucidate the interpretation of single and serial sections: differing methods of mounting adjacent sections, observation of the same section by high-angle stereoscopy, and examination of sections which have been shadowed prior to and subsequent to electron microscopy. It is found that the appearance of sections is independent of the choice of side to be placed against the formvar films. Stereoscopy shows that the appearance of fine structures is strongly dependent upon the direction of the penetrating electron beam with respect to the plane of the structures. Stereoscopy, combined with shadowing, shows quantitatively that extensive sublimation of polymer occurs upon normal exposure in the electron microscope. Observation of sections shadowed prior to electron microscopy indicates that varying amounts of material are removed between sections by the action of microtomy; i.e., it is probable that the sum of the thicknesses of several serial sections is considerably less than the total thickness of material removed from the block. It is believed that this effect, combined with the effect of sublimation, aids in explaining the failure of adjacent sections to exhibit continuity in their detailed structures.
本文描述了一种用于电子显微镜的连续切片固定方法。连续切片在解释方面存在某些异常情况，以至于无法对切片组织进行完整而详细的三维重建。本文讨论了这些异常情况以及在单张切片解释中遇到的异常情况。为了阐明单张切片和连续切片的解释，进行了以下几类观察：相邻切片的不同安装方法、通过高角度立体观察对同一切片的观察以及对在电子显微镜检查之前和之后进行了阴影处理的切片的检查。结果发现，切片的外观与放置在福尔马膜上的面的选择无关。立体观察表明，精细结构的外观强烈依赖于穿透电子束相对于结构平面的方向。立体观察与阴影处理相结合，定量地表明在电子显微镜正常曝光时聚合物会发生大量升华。对在电子显微镜检查之前进行了阴影处理的切片的观察表明，切片之间由于切片操作会去除不同量的材料；也就是说，几个连续切片的厚度总和很可能远小于从组织块中去除的材料的总厚度。据信，这种效应与升华效应相结合，有助于解释相邻切片在其详细结构上缺乏连续性的现象。
