[Toxic organic damage]

Pathohistological findings are playing an important role in the advice of toxic organ damages. After presentation of some details about the frequency of toxic organ damages, the pathways of toxic agents in the organism are discussed. In cells toxic damage may induce cell necrosis, functional disturbance, inhibition of cell proliferation or malignant transformation; in extracellular structures it may lead to degradation phenomena in the connective tissue matrix. As demonstrated in example of calciphylaxis, a combination of different noxes may not only add but even potentiate the effects of the single noxes. In intracellular reparation processes the lysosomal system is involved. In case of necrosis regeneration is possible in most kinds of tissues, if connective tissue rails are preserved. Otherwise an irreversible reparative fibrotic alteration of organ structure is induced which develops according to particular general and schematic rules. As mostly character and course of the tissue reaction is unspecific, pathohistological findings do not enable conclusions on the type of inducing toxic agent. The following presentation of some examples of toxic damages with pathognomonic histological appearance deals with asbestosis, silicosis, chloroquine-induced cardiomyopathy, aluminum-induced osteopathy and a recently described liver cirrhosis in early childhood induced by copper-containing drinking water. Some limits of traditional pathohistological evaluation of toxic organ damages have been overcome by application of new morphological techniques. Own investigations revealed that the immunocytochemical demonstration of the C5b-9-complement complex enables a better and earlier detection of irreversibly damaged cells. Discrimination of toxic and virus-induced tissue damage is facilitated by the technique of in-situ-hybridization. Sometimes a specific recognition and localization of toxic agents is achieved by X-ray microanalysis, electron-spectroscopic imaging (= ESI) resp. laser microprobe mass spectrometry (= LAMMA); comparing these techniques X-Ray microanalysis and ESI, both, enable specific identification of chemical elements, while LAMMA, in addition, offers some information about the involved molecules and isotopes.