[Ultrastructural and autoradiographical investigations of early changes in experimental lung fibrosis (author's transl)].

Electron microscopical, autoradiographical and histochemical investigations were carried out in experimental lipid pneumonia, 6 weeks after exposure to mineral oil. In the lungs developed granulomatous changes with fibroblasts, some macrophages and leucocytes. With the aid of electron microscopy an increased number of fibroblasts with predominantly extracellular localized collagen fibers were visible in the granulomatous foci. Autoradiograms with 3H-Thymidine show an six-fold increase of number of radioactive labelled nuclei of fibroblasts in the granulomatous areas. This two methods--electron microscopy and autoradiography--appear sufficient for early detection of changes in experimental lung fibrosis.