Cytophotometric Feulgen-DNA measurement was carried out on mesothelial cells in 40 pleural effusions (malignant: 20, non-malignant: 20 cases) obtained from 40 autopsy cases. No significant difference was found between the DNA amounts of mesothelial cells in malignant effusion and those in non-malignant effusion. However, histological examination of the pleurain 40 cases, showed that the DNA amounts of mesothelial cell change according to the inflammatory stage of pleuritis. In the early stage

more »

... pleuritis showing pleural edema, slight hemorrhage and infiltration of some inflammatory cells, the mesothelial cells in non-malignant effusion showed a significantly higher DNA value than in malignant effusion. On the contrary, at the stage of fibrofibrinous pleuritis, the former showed a lower DNA value than the latter. In addition, accompaniedwith the progression of the inflammatory stage of pleuritis, a peculiar alteration of the mesothelial DNA amounts was confirmed in both malignant and non-malignant effusions. The pathogenesis was discussed with regard to such cell kineticsof mesothelial cells in pleural effusions.