PATHOHISTOLOGICAL AND ELECTRON MICROSCOPIC STUDIES OF THE LUNG IN MITRAL STENOSIS WITH SPECIAL REFERENCE TO THE CORRELATION BETWEEN MORPHOLOGICAL CHANGES AND CARDIOPULMONARY DYNAMICS

Abstract

There have been many studies on the correlation between histological changes of the lung an, d clinical findings or cardiopulmonary dynamics in mitral stenosis. However, there are still different opinions as to this correlation. In this presentation the relation between pulmo-nary circulatory disturbances and histological or electron-microscopical findings in patient with mitral stenosis was investigated. Material The investigation was made of 12 patients with mitral stenosis. All patients were submitted to surgical treatment (commissurotomy). Cardio-pulmonary function tests were performed prior to the operation except one. The lung from a patient with mild tuberculosis was investigated for comparison. Methods Small piece of the lung was excised form the lingual region of the left lung at commissurotomy. The specimen was immediately divided into two parts, and a part of them was fixed by infusion using I per cent osmic acid for electron microscopic examination, the other part was fixed with 10 per cent formaldehyde for histological examination. Histological preparations were made in usual fashion, and hematoxylin-eosin, PAS, van Gieson's and Verhoeff's procedures were employed for tissue staining. The fixed specimen for electron-microscopic examination was embedded into methacrylate after preliminary washing with water and following dehydration. And then submitted to ultra-microtome. The slices thus obtained were mounted on a formvar coated mesh for electronmicroscopic observations and photogram. Results (1) It was found histologically that the changes in lung tissue progressed in the order of dilatation of capillaries, thickening of capillary wall and then thickening of alveolar wall. Thickening of alveolar wall was seen in 7 of 12 cases. Moderate to advanced thickening of alveolar wall was accompanied with fibrosis, and the more thickening advanced, the more fibrotic changes became remarkable. Decrease in number of capillaries was predominant and cuboidalization of the alveolar wall was noted in such cases.