Silver M M, Hearn S A, Lines L D, Troster M
Department of Pathology, Hospital for Sick Children, Toronto, Ontario, Canada.
J Histochem Cytochem. 1988 Aug;36(8):1031-6. doi: 10.1177/36.8.3392392.
We used a post-embedding immunoelectron microscopy method, using protein A-gold, to detect calcitonin and chromogranin A immunoreactivity in three cases of human medullary thyroid carcinoma. Because the epoxy-embedded tissue had been fixed (glutaraldehyde or formaldehyde) and osmicated before embedment, the proteins were identified in optimally preserved tissue. Uranyl and lead staining was used after immunolabeling, so that the tissue was also optimally contrasted. The morphological advantage provided by osmication was tested by labeling rat thyroid gland C-cells for calcitonin. The protein A-gold technique allowed localization of both antigens to the contents of membrane-bound secretory granules in the tumor cells. In one case, labeling density for each antigen was measured over several intercellular compartments and the interstitium. Calcitonin, but not chromogranin A, reactivity was also identified in intracellular amyloid fibrils in two cases, showing that the constant region of calcitonin is preserved in amyloid deposits related to the tumor cells.
我们采用包埋后免疫电子显微镜方法，利用蛋白A-金，检测3例人甲状腺髓样癌中降钙素和嗜铬粒蛋白A的免疫反应性。由于环氧树脂包埋的组织在包埋前已用戊二醛或甲醛固定并经锇酸处理，因此在保存最佳的组织中鉴定出了这些蛋白质。免疫标记后使用铀和铅染色，使组织的对比度也达到最佳。通过对大鼠甲状腺C细胞进行降钙素标记，测试了锇酸处理所提供的形态学优势。蛋白A-金技术可将两种抗原定位到肿瘤细胞膜结合分泌颗粒的内容物中。在1例中，在几个细胞间区室和间质中测量了每种抗原的标记密度。在2例中，还在细胞内淀粉样原纤维中鉴定出降钙素而非嗜铬粒蛋白A的反应性，表明降钙素的恒定区在与肿瘤细胞相关的淀粉样沉积物中得以保留。
