Ishikawa T, Masahito P, Nemoto N, Matsumoto J, Shima A
J Natl Cancer Inst. 1986 Aug;77(2):521-8.
Neurinomas developed in an African lungfish (Protopterus annectens), living in an aquarium in Western Japan. The 2 tumors, measuring 7.5 X 9.0 X 6.5 and 13 X 4 X 6 cm, were located on the skin. As shown by light microscopy, tumor cells were composed of spindle-shaped cells with huge pleomorphic nuclei, which were arranged in parallel rows or whorls in interlacing connective tissue. Long-term culture of these tumor cells was achieved in vitro at 25 degrees C with use of conditioned medium over a period of more than 4 months. The nuclear DNA contents of erythrocytes (normal diploids, 2C) and tumor cells dispersed from the fixed tumor tissues were measured by 4',6-diamidino-2-phenylindole hydrochloride-DNA microfluorometry by using mouse cerebellar small granule cells (normal diploids, 2C) as a reference. The 2C value of the lungfish was approximately 28-fold greater than that of the mouse. Furthermore, consistent with the nuclear pleomorphism observed by light microscopy, the nuclear DNA contents of tumor cells showed a wide distribution from hypo-2C to hyper-4C. DNA repair synthesis was measured autoradiographically in organ cultures of the tumor, lung, and skin, exposed to chemical carcinogens or UV radiation. Considerable repair was observed in the tumor and skin cells exposed to 1-methyl-1-nitrosourea (CAS: 684-93-5), N-methyl-N'-nitro-N-nitrosoguanidine (CAS: 70-25-7), or 254-nm or sunlamp UV light. Only traces of repair synthesis were detected in lung exposed to 1-methyl-1-nitrosourea or N-methyl-N'-nitro-N-nitrosoguanidine. 4-Hydroxyaminoquinoline 1-oxide (CAS: 4637-56-3) did not induce repair in any of the three tissues. The observed values for repair, relative to the amount of DNA, were similar to those in other fishes.
在日本西部一个水族馆饲养的非洲肺鱼（Protopterus annectens）身上长出了神经鞘瘤。这两个肿瘤大小分别为7.5×9.0×6.5厘米和13×4×6厘米，位于皮肤表面。光学显微镜检查显示，肿瘤细胞由梭形细胞组成，细胞核具有巨大的多形性，在交织的结缔组织中呈平行排列或漩涡状排列。利用条件培养基，在25摄氏度下对这些肿瘤细胞进行了体外长期培养，培养时间超过4个月。通过盐酸4',6-二脒基-2-苯基吲哚-DNA显微荧光测定法，以小鼠小脑小颗粒细胞（正常二倍体，2C）作为参照，测量了固定肿瘤组织中分散的红细胞（正常二倍体，2C）和肿瘤细胞的核DNA含量。肺鱼的2C值约为小鼠的28倍。此外，与光学显微镜观察到的核多形性一致，肿瘤细胞的核DNA含量显示出从低于2C到高于4C的广泛分布。在暴露于化学致癌物或紫外线辐射的肿瘤、肺和皮肤器官培养物中，通过放射自显影法测量了DNA修复合成。在暴露于1-甲基-1-亚硝基脲（CAS：684-93-5）、N-甲基-N'-硝基-N-亚硝基胍（CAS：70-25-7）或254纳米紫外线或日光灯紫外线的肿瘤和皮肤细胞中观察到了显著的修复。在暴露于1-甲基-1-亚硝基脲或N-甲基-N'-硝基-N-亚硝基胍的肺中仅检测到微量的修复合成。4-羟基氨基喹啉1-氧化物（CAS：4637-56-3）在这三种组织中均未诱导修复。相对于DNA量观察到的修复值与其他鱼类中的值相似。
