[The role of several occupational factors in the development of pulmonary alveolar proteinosis (an experimental study)].

The article deals with results of morphological and electron-microscopy studies of the lungs in experimental pulmonary alveolar proteinosis in rats. The disease was reproduced in experiments on 500 animals by means of chronic inhalation of electro-welding copper-containing aerosols, condensations (smokes) which may develop under similar concentrations during electric welding. The lungs were investigated at intervals ranging from several days to two years from the beginning of the experiment, the duration of which was 9 months, the dayly exposure of the animals in inhalation cameras being three hours. The intra-alveolar content was composed of products of accelerated life activity of the cells of the alveolar epithelium as well as of perished phagocytes (proteins, lipids). The degree of manifestation of the process depended upon concentration of aerosol and duration of the experiment. In the zones of pulmonary alveolar proteinosis there were observed thickenings of the basal membranes, sclerosis of interalveolar partitions, slow replacement of perished macrophages by new ones, which were the causes of prolonged resolution of the alveols content. Pulmonary alveolar proteinosis (lipoproteinosis) should not be considered as a variety of pneumonia or edema of alveols.