218 research outputs found
Histochemical and Ultrastructural Study of Clara Cell Granules in the Guinea Pig
Histochemical studies using light and electron microscopes were undertaken to see what chemical components make up the Clara cell granules in guinea pig lung. Light microscopically, it was suggested that they may contain a variable amount of proteins, carbohydrates, and phospholipids. On the other hand, electron microscopic examination with digestive treatment with pepsin as well as chloroform-methanol clearly demonstrated that the main component of the crystalline granules of the guinea pig Clara cells was the proteins. It was, therefore, concluded that Clara cell granules are complex compounds made up mainly of proteins with small amounts of carbohydrates and phospholipids
Epithelial Mucinosis in Exophytic Endobronchial Squamous Cell Carcinoma
Three cases of exophytic squamous cell carcinoma of the lung in which an unusual epithelial change with intercellular mucin deposit; namely epithelial mucinosis, was present in variable degree are reported here. As either exophytic variant of lung carcinomas or its mucinotic change is rare, the general concept of this lung carcinomas is summarized and the significance of epithelial mucinosis is discussed
Membranous Fibrosis of the Lung
Membranous fibrosis of the lung depicts a morphological feature of the fibrous tissue which covers alveolar duct walls. Membranous sheets of fibrous tissue usually bridge and obstruct the mouths of alveoli, and attach only at the tips of the septa; i.e., the alveolar duct walls, and often provoke a collapse of alveolar spaces. There seem to be two types of membranous fibrosis. The first type is, in fact, a fibrous replacement of pre-existing hyaline membrane, while the second is a de novo formation of membranous fibrous tissue which has little or no preceding hyaline membrane. We consider that both of these changes result from damage to the alveolar duct walls and may constitute forms of the fibrosing alveolar ductitis syndrome. Recognition of this type of fibrosis gives us a better understanding of the morphogenesis of so-called diffuse alveolar damage
Epithelial Membrane Antigen in Normal Lung Tissue -A Tool for Identifying Alveolar Epithelial Lining
Intraluminal (Intra-alveolar) Diffuse Fibrosis of the Lung
The present communication describes the morphology, etiology and mechanisms of intraluminal (or intra-alveolar) diffuse fibrosis of the lungs. Pulmonary fibrosis is the end-stage of tissue injury in the lungs and is usually non-specific. The determination of its original cause is difficult, but intraluminal diffuse fibrosis with loose stroma is quite unique and characteristic. In addition to paraquat lungs, we herein show that radiation pneumonitis, infarction, and some forms of bronchiolitis obliterans may cause this type of fibrosis. It is speculated that intraluminal diffuse fibrosis is the result of severe alveolar epithelial damage occurring diffusely and continuously, followed by edema and organization of the alveoli
Intraluminal Polypoid Fibrosis of the Lung
The present communication describes the morphology and pathogenesis of intraluminal (or intra-alveolar) polypoid fibrosis of the lungs, which is a condition characterized histologically by the presence of polypoid fibrous tissue masses protruding into and filling lumens of the airways or airspaces. Intraluminal polypoid fibrosis is further subclassified into three types. The first type probably represents a primary injury of respiratory bronchioles and alveolar duct walls which directly leads to polypoid fibrous tissue formation. This fibrous tissue is generally uniform in appearance and lacks a fibrinous component. The second type results from fibrous replacement of preceding fibrinous inflammation in the airspaces, such as lobular (broncho-) and lobar pneumonia. It is histo logically characterized by an admixture of fibrin and fibrous components. The third type superimposes on hyaline membrane formation. The spaces surrounded by the hyaline membrane along the alveolar duct walls are filled with loose fibrous tissue. In all three types, the process of organi zation originates in the alveolar duct walls, especially at the edge of alveolar mouths. Therefore, we propose the term of "fibrosing alveolar ductitis syndrome" for such disease entities as BOOP, BIP, and organized DAD. in which damage of the alveolar duct wall results in fibrosis
- …