Studies on the mechanism of cadmium-induced toxic effects(Autoradiographic demonstration of cadmium unbound to metallothionein)

描述了一种新的放射自显影技术，用于展示组织切片中未结合金属硫蛋白的微量“游离镉”。这是通过使用[14c -1,4,5,8-萘酚]-1-（噻唑偶氮）-2-萘酚（TAN）代替金属放射性同位素实现的。在这种方法中，用标记的TAN水溶液对组织切片进行染色，然后将切片置于2-丙醇中以去除任何未反应的TAN。去污切片最后进行常规放射自显影程序。在注射了稀释的醋酸镉水溶液的组织制备的切片中，观察到在有色区域上有高浓度的颗粒。这证明了根据镉在组织中的化学形态来鉴别镉的可行性。这项技术可以提供关于镉在生物系统中的毒性的额外信息。

A new autoradiographic technique for demonstrating trace amounts of "free cadmium" which remains unbound to metallothionein in a tissue section is described. This was realized by the use of [14C-1,4,5,8-naphthol]-1-(thiazolylazo)-2-naphthol (TAN) instead of a metal-radioisotope. In this method, tissue sections were stained with an aqueous solution of labeled TAN, and then the sections were placed in 2-propanol in order to remove any unreacted TAN. The decontaminated sections were finally subjected to the usual autoradiographic procedure.A high concentration of grains overlying coloured regions was observed in sections prepared from tissues injected with a diluted aqueous solution of cadmium acetate. This demonstrated the feasibility of the differential demonstration of cadmium according to its chemical forms in tissues. This technique may yield additional information as to the toxicity of cadmium in biological systems.