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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Considerable progress has been made in the localization of chemical substances within the gas-exchange zones of vertebrate lungs since cytochemical techniques suitable for use with the electron microscope have been developed. The light microscope, an instrument with an effective resolution limit of about 0.2 micron, is ill-suited for studying regions such as these where small tissue elements are arranged in a complex manner. A wide range of acid hydrolases have been detected in the vacuoles and dense bodies of alveolar macrophages by means of cytochemical techniques. The enzymes demonstrated in this way include acid phosphatase, aryl sulphatase, cathepsin D, beta-glucuronidase, acetyl glucosaminidase, nonspecific esterase, dipeptidyl peptidase II and dipeptidyl peptidase IV. Such enzymes are, of course, to be expected in the lysosomes of cells which have a primary phagocytic role. Nevertheless, it must be confessed that very little is yet known about the actual mechanism of phagocytosis or of the fate of the digested material. It is fortunate, however, that some of the tools which are likely to be of value in research on these aspects of macrophage function are currently being developed. Of particular interest in this connection are the immunocytochemical techniques which permit the localization of surface-associated antigens and intracellular contractile proteins. It must be emphasized that phagocytosis is not the only function of macrophages in the gas-exchange zone of the lung. These cells are thought to be involved in the presentation of exogenous antigenic material to the reactive cells of the lymphoid system. Recent research has also indicated that mammalian alveolar macrophages synthesize a diverse range of substances. Furthermore, the elastases associated with pulmonary macrophages are now thought to be involved in the pathogenesis of emphysema. All of the above-mentioned activities are of great biological and clinical significance and, consequently, merit the cytochemists' attention in future. The epithelial lining of the greater part of the pulmonary gas-exchange area is composed of type I pneumonocytes. In terms of ultrastructure, these are very specialized cells; their extensive and highly-attenuated cytoplasmic processes form the outer layer of the air-blood barrier. No special carrier systems have been identified within type I pneumonocytes and this is in keeping with the claims that oxygen is transferred across the alveolar tissue barrier by a process of simple diffusion. Type II pneumonocytes, in contrast, have considerable metabolic activity.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cytochemistry of the gas-exchange area in vertebrate lungs. 355 66

The aim of the study was to evaluate the protease and antiprotease activity in the fluid obtained from the culture of cells isolated from the lungs of animals with experimental emphysema. An attempt was made to correlate the results of biochemical examinations with adherence degree and ultrastructural changes of the surface of BAL-isolated cells. The experiment was carried out on male Wistar rats, of 180-220 g b.w. Two i.p. injections of BCG-vaccine (4 x 10(8) microorganisms) on the 1st and 14th day were applied as macrophage mobilizing and activating agent. Papain (2 mg/l ml/100 g b.w.) was given once i.t. on the 21st day. The animals were sacrificed on the 28th day of the experiment. We found a correlation between the increase in the cell adherence and ultrastructural changes (in SEM), suggesting an increased activity of the cells isolated from BCG-treated rats. In the culture medium of cells isolated from the rats which were given BCG or papain and BCG+papain we observed an increased base protease activity and decreased Cathepsin D activity comparing with the control group. Increased antitrypsin activity in the BCG and BCG+papain-treated rats and decreased antitrypsin activity in papain-treated rats only was observed, too. There was no obvious difference in the levels of the antiplasmin and antichymotrypsin activities between the groups. The present results indicate that activated pulmonary macrophages are one of the sources of the protease-antiprotease intraalveolar imbalance. However, an increased production of proteolytic enzymes may not be the only factor responsible for the progression of lung emphysema in BCG-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of morphological and biochemical changes of BAL-isolated cells in experimental lung emphysema. 749 38

Aim of the present study was to evaluate cathepsin D, base protease, antiplasmin, antitrypsin and antichymotrypsin activities and protein content in the 24h culture medium of the alveolar macrophages (AM) deriving from the rats treated BCG-vaccine and from rats with papain-induced emphysema. In the culture medium of cells isolated from the rats which were given BCG or papain and BCG+papain we observed an increase of base protease activity and a decrease of cathepsin D activity comparing with control group. Increased antitrypsin activity in BCG and BCG+papain-treated rats and decreased antitrypsin activity in papain-treated rats were observed. There were not significant differences in antiplasmin and antichymotrypsin activities between examined groups. The obtained results indicate that activated pulmonary macrophages are one of the sources of the protease-antiprotease intraalveolar imbalance. However, increased production of proteolytic enzymes may not be the only factor responsible for the progression of lung emphysema in BCG-treated rats.
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PMID:The effect of activated alveolar macrophages on experimental lung emphysema development. I. Protease and antiprotease activities in the culture medium of alveolar macrophages. 883 14

An imbalance between proteinases and their inhibitors is believed to play an essential role in the development of chronic obstructive pulmonary disease (COPD) and pulmonary emphysema. COPD is mainly caused by cigarette smoking, and is characterized by an increase in inflammatory cells in small airways and lung parenchyma. We examined the mRNA expression of several proteinases in lungs of mice exposed to cigarette smoke or control air. After 1, 3 and 6 months' smoke exposure there was a significant increase of matrix metalloproteinase (MMP)-12 and Cathepsin D mRNA, compared to air-exposed mice. To determine the cellular origin of MMP-12 and Cathepsin D, we isolated dendritic cells (DCs) and macrophages from the lungs of mice. There was an increase in MMP-12 mRNA after smoke exposure in both macrophage and DC populations, whereas Cathepsin D was predominantly expressed in macrophages. Immunohistochemistry clearly revealed the expression of Cathepsin D protein in alveolar macrophages of cigarette smoke-exposed mice, in contrast to air-exposed littermates. Western blots on lung tissue demonstrated an increase of MMP-12 protein in cigarette smoke-exposed animals. These results indicate that cigarette smoke increases the expression of MMP-12 and Cathepsin D in the lungs of mice, and that not only macrophages but also DCs produce MMP-12.
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PMID:Matrix metalloproteinase-12 and cathepsin D expression in pulmonary macrophages and dendritic cells of cigarette smoke-exposed mice. 1619 42