Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cathepsin B activity was quantitated in alveolar macrophages obtained from hamsters 10, 21, and 105 days after the intratracheal instillation of porcine pancreatic elastase, bleomycin, or normal saline. Alveolar macrophages lavaged from animals receiving elastase contained significantly higher enzyme levels at 21 and 105 days (16,200 and 17,000 U/mg protein/hr, respectively) as compared with saline-treated animals (12,300 units). In contrast, cells from animals receiving bleomycin showed a decrease in activity at 21 and 105 days (9700 and 9900 units, respectively). At 10 days enzyme levels did not differ significantly. The results suggest that cathepsin B levels in alveolar macrophages reflect differences in lung destruction and connective tissue repair in vivo. In addition, the finding of high cathepsin B activity in animals with emphysema suggests the possibility that cysteine proteases contribute to progressive lung destruction initiated by the intratracheal instillation of elastase.
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PMID:High cathepsin B activity in alveolar macrophages occurs with elastase-induced emphysema but not with bleomycin-induced pulmonary fibrosis in hamsters. 245 29

Cathepsin B is a lysosomal enzyme of importance in many physiological and pathological processes. Its distribution in human tissues was studied by an indirect immunoperoxidase method. Cathepsin B was demonstrated in macrophages, hepatocytes, renal tubules, gastrointestinal epithelium and fibroblasts, confirming previous studies. It was demonstrated for the first time by immunohistology in several other tissues, especially stratified squamous epithelium, transitional epithelium, salivary glands, pancreas, central and peripheral neuronal cell bodies, trophoblast and all endocrine organs. Widespread distribution of cathepsin B has been postulated several times but this is the fullest evidence that the enzyme indeed occurs in many organs. In pathology cathepsin B has so far been thought to be involved in demyelination, emphysema, rheumatoid arthritis and neoplastic infiltration.
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PMID:The distribution of cathepsin B in human tissues. 388 45

Elastin is an extracellular matrix protein critical to the normal structure and function of human lung. Recently reported data indicate that live human alveolar macrophages can degrade purified elastin in vitro. In this study, we directly compared the elastolytic activity of alveolar macrophages with that of human neutrophils. In the absence of proteinase inhibitors, human neutrophils degrade much more elastin than do human alveolar macrophages. However, macrophages cultured in 10% human serum and in contact with purified 3H-elastin degraded 4.7 micrograms elastin/10(6) cells per 24 h, as compared to less than 1 microgram/10(6) cells/24 h for neutrophils. We observed a similar pattern when the two cells were cultured in human alveolar fluid. We determined that the relative resistance of macrophage elastolytic activity to serum or alveolar proteinase inhibitors was not simply due to phagocytosis of substrate by the larger macrophages. Live macrophages as well as neutrophils degrade 125I-elastin coupled to noningestible sepharose beads. Again in serum-free media, neutrophils degraded eight-fold more elastin than macrophages but only macrophages degraded sepharose-coupled elastin in the presence of 10% serum. Because of these findings, we compared the enzymatic mechanisms of elastin breakdown by macrophages with that of neutrophils. Macrophage elastolytic activity is largely (65-80%) due to a cysteine proteinase(s), at least part of which is Cathepsin B. Approximately half of the cysteine proteinase activity appeared to be expressed at or near the cell surface. These experiments defined two enzymatically distinct pathways of elastin breakdown by human inflammatory cells: the classic, neutrophil derived soluble elastase(s) that is sensitive to serum and alveolar proteinase inhibitors, and a macrophage-mediated pathway that is largely cell associated and relatively resistant to inhibitors. The function of the two pathways depends on the relative excess or deficiency of soluble inhibitors. At inflammatory sites rich in proteinase inhibitors, tissue macrophages may degrade more extracellular matrix elastin than neutrophils. In smokers without antiproteinase deficiency, pulmonary macrophages, which are known to be increased in number, may be the more important cause of elastin breakdown and emphysema.
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PMID:Comparison of live human neutrophil and alveolar macrophage elastolytic activity in vitro. Relative resistance of macrophage elastolytic activity to serum and alveolar proteinase inhibitors. 656 28