Itoh Y, Inoue M, Amano N, Yagashita S
Division of Pathology, Kanagawa Rehabilitation Centre, Japan.
Neuropathol Appl Neurobiol. 1997 Aug;23(4):326-30.
The three dimensional structure of filaments in Pick bodies and ballooned neurons in an autopsy case of Pick's disease was examined by scanning electron microscopy (SEM) and compared with the appearances on transmission electron microscopy (TEM). SEM revealed two types of filament in Pick bodies; one type was randomly orientated straight filaments of about 20 nm in width and the other was twisted helical filaments resembling paired helical filaments (PHFs). The maximum diameter of helical filaments was 44 nm with periodic constrictions of about 200 nm; the direction of the helix was left-handed. Ballooned neurons contained mainly randomly arranged filaments, 17-22 nm diameter. The three types of filament described here were greater in diameter in SEM images than in TEM; this may be due to the fixed increased thickness of 10 nm due to the platinum pallidium compound coating. However, SEM images are much more suitable than TEM profiles for three dimensional analysis of filamentous structures, especially those with helically twisted profiles; preparation for SEM did not change the periodicity of the twisted structures or the direction of the helix on these filaments even after metal coating. SEM has proved to be an effective and straightforward method for assessing the arrangement, direction and distribution of filaments and this technique could be applied to similar structures in other diseases.
通过扫描电子显微镜（SEM）检查了一例皮克病尸检病例中皮克小体和气球样神经元内细丝的三维结构，并与透射电子显微镜（TEM）下的外观进行了比较。SEM显示皮克小体内有两种类型的细丝；一种是宽度约为20nm的随机排列的直细丝，另一种是类似于双螺旋细丝（PHF）的扭曲螺旋细丝。螺旋细丝的最大直径为44nm，周期性收缩约为200nm；螺旋方向为左旋。气球样神经元主要含有随机排列的细丝，直径为17 - 22nm。此处描述的三种类型的细丝在SEM图像中的直径比在TEM中更大；这可能是由于铂钯化合物涂层导致固定增加了10nm的厚度。然而，对于细丝状结构的三维分析，尤其是那些具有螺旋扭曲轮廓的结构，SEM图像比TEM图像更合适；即使在金属涂层后，SEM的制备也没有改变这些细丝上扭曲结构的周期性或螺旋方向。SEM已被证明是评估细丝排列、方向和分布的一种有效且直接的方法，并且该技术可应用于其他疾病中的类似结构。
