muramidase and Pneumoconiosis

Serum angiotensin-converting enzyme activity (SACE) and lysozyme activity were measured in a group of 40 underground coal miners and two control groups, 20 subjects with sarcoidosis and 15 normal non-dust-exposed volunteers. The miners were grouped first according to whether they had recent exposure (still actively mining or retired three years or less prior to measurement) or temporally more distant exposure (retired more than three years prior to measurement). Secondly, they were grouped as to whether or not they had coal workers' pneumoconiosis (CWP). The subjects with sarcoidosis were grouped according to disease activity. As expected, the subjects with active sarcoidosis had elevated SACE activity compared with normal subjects. The coal miners as a group did not have elevation of their SACE activity. However, the coal miners with recent exposure had elevated SACE activity (57.1 +/- 3.9 U/ml) compared with normal controls (43.8 +/- 1.5 U/ml, p = 0.007). The SACE activity in miners without recent exposure was not elevated (39.8 +/- 1.3 U/ml) compared with the normal controls. No increase in SACE activity was found when the miners were grouped according to the presence or absence of CWP. In contrast, the miners' serum lysozyme activity was not elevated. Since alveolar macrophages are a potential source of SACE, elevation of SACE activity in underground coal miners may reflect alveolar macrophage activation caused by increased pulmonary mixed coal mine dust burden. Furthermore, since both SACE and serum lysozyme are elevated in association with silicosis, these findings may confirm that the macrophage responses to inhaled silica and coal dust differ.

Topics: Coal Mining; Humans; Lung Diseases; Macrophage Activation; Macrophages, Alveolar; Male; Middle Aged; Muramidase; Occupational Exposure; Peptidyl-Dipeptidase A; Pneumoconiosis; Sarcoidosis; Time Factors

Topics: Adult; Aged; Ceramics; Humans; Male; Middle Aged; Muramidase; Pneumoconiosis

Topics: Administration, Intranasal; Adult; Aerosols; Coal Mining; Drug Evaluation; Humans; Kazakhstan; Male; Middle Aged; Muramidase; Occupational Diseases; Pneumoconiosis; Polysaccharides, Bacterial; Prodigiozan

The studies reviewed in this chapter provide further evidence that the secretion of lysosomal enzymes and other hydrolases is a constitutive function of certain cells whereas in other cells is an inducible process probably contributing to the pathology of a variety of diseases. Little is known of the mechanisms mediating the secretion of lysosomal enzymes. We have summarized evidence suggesting a role of microfilaments and microtubules in controlling enzyme release, but further studies of the biochemical mechanisms which control the activity of these subcellular structures are required. The fusion of lysosomes with the plasma membrane has been observed in several situations and the mechanisms underlying processes of this nature have been studied in lower organisms (Satir et al. 1973; Plattner 1974). Agents, such as concanavalin A, which interfere with the fusion of endosomes with lysosomes (Goldman 1974; Edelson and Cohn 1974a, b) should also be useful in determining the chemical nature of membrane components involved in the fusion process. New information on the fate of secreted acid hydrolases has been obtained from studies of the uptake of lysosomal enzymes by fibroblasts. Clearly, the mechanisms by which these cells endocytose secreted lysosomal enzymes will be a subject for detailed study in view of the important of directing enzymes and drugs into lysosomes (De Duve et al. 1974). The mechanisms by which extracellular inhibitors inactivate hydrolytic enzymes, particularly proteinases, is also being clarified (for review see Davies 1975) and this should aid in finding new ways for preventing tissue damage caused by the excessive secretion of these enzymes. Further investigation concerning the secretion of lysosomal enzymes should establish the essential physiological role which these enzymes play at both extracellular and intracellular sites. Also, a close examination of the interaction of both endogenous and exogenous stimuli of inflammation with cells resulting in the secretion of hydrolytic enzymes, will clarify the mechanisms underlying the initiation and progression of the inflammatory process in its diverse forms.

Topics: Animals; Anti-Inflammatory Agents; Antigen-Antibody Complex; Bone Resorption; Carrageenan; Cell Transformation, Neoplastic; Cell Wall; Complement System Proteins; Cytochalasin B; Dental Plaque; Glucuronidase; Humans; Hydrolases; Inflammation; Lysosomes; Macrophages; Microbial Collagenase; Muramidase; Neutrophils; Nucleotides, Cyclic; Plasminogen Activators; Pneumoconiosis; Streptococcus pyogenes