Application on Timm sulphide silver method for electron microscope localization of lead ions in blood cells

The application of the Timm sulphide silver method for the demonstration of lead ions in peripheral blood cells is investigated, using male white adult Wistar rats treated with a single dose of lead acetate, range 150 mg/kg b.w. To improve the Timm reaction for electron microscopy, fixation of whole cells with glutaraldehyde fixative solution saturated with H2S, an agarose embedding and physical development of thick sections without prior cryostat sectioning are presented. At 6.0 hours after injection both erythrocytes as well as white cells reveal the positive Timm reaction. All types of blood cells contain numerous cytoplasmic precipitates illustrating the intracellular lead accumulation. It is shown that the invaginations of white cell nuclear membrane possess a storing function as areas of lead depots. As a rule, the neutrophils display a highest amount of cytoplasmic precipitates and exclusively a low amount of reaction products in basophils is observed. At 14 days after injection, precipitates are present only in erythrocytes and monocytes. A suggestion of a possible functional significance of changes in the Timm staining pattern in blood cell types is discussed in this paper.