Silver Impregnation Methods in Diagnostics
Silver impregnation includes classical techniques, which have revolutionalized histochemistry and neuroscience for over 100 years. Initial probing of the target with silver ion to form silver atom in situ and its subsequent amplification for better visualization are both regulated by catalytic reaction of silver ion, which could be sometimes capricious. Recent progress has achieved sensitive and less capricious visualization of the targets by introducing physical developer. Because the final visualization is uniformly mediated by silver grains, silver-impregnated targets are labeled “argyrophilic” regardless of the method used. In diagnostic neuropathology, however, argyrophilia could be heterogeneous and dependent on the target and method, possibly representing qualitative differences indicative of the nature of the target. This empirical correlation between argyrophilic profiles and tau...