Inorganic dust pneumonias: the metal-related parenchymal disorders.
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In recent years the greatest progress in our understanding of pneumoconioses, other than those produced by asbestos, silica, and coal, has been in the arena of metal-induced parenchymal lung disorders. Inhalation of metal dusts and fumes can induce a wide range of lung pathology, including airways disorders, cancer, and parenchymal diseases. The emphasis of this update is on parenchymal diseases caused by metal inhalation, including granulomatous disease, giant cell interstitial pneumonitis, chemical pneumonitis, and interstitial fibrosis, among others. The clinical characteristics, epidemiology, and pathogenesis of disorders arising from exposure to aluminum, beryllium, cadmium, cobalt, copper, iron, mercury, and nickel are presented in detail. Metal fume fever, an inhalation fever syndrome attributed to exposure to a number of metals, is also discussed. Advances in our knowledge of antigen-specific immunologic reactions in the lung are particularly evident in disorders secondary to beryllium and nickel exposure, where immunologic mechanisms have been well characterized. For example, current evidence suggests that beryllium acts as an antigen, or hapten, and is presented by antigen-presenting cells to CD4+ T cells, which possess specific surface antigen receptors. Other metals such as cadmium and mercury induce nonspecific damage, probably by initiating production of reactive oxygen species. Additionally, genetic susceptibility markers associated with increased risk have been identified in some metal-related diseases such as chronic beryllium disease and hard metal disease. Future research needs include development of biologic markers of metal-induced immunologic disease, detailed characterization of human exposure, examination of gene alleles that might confer risk, and association of exposure data with that of genetic susceptibility. (+info)
A novel actinomycete from sugar-cane bagasse: Saccharopolyspora hirsuta gen. et. sp. nov.
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A new species of nocardioform actinomycete isolated from spontaneously heated sugar-cane bagasse is described as Saccharopolyspora hirsuta gen. et sp. nov. It has affinities with species of both Nocardia and Actinomadura but can be distinguished from both genera by its morphology, sporulation, wall and lipid analyses, antibiotic resistance, degradation and carbon utilzation tests. (+info)
The composition of massive lesions in coal miners.
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The nature of the material forming the massive lesions in the lungs of coal workers has never been demonstrated. The concept that it was in fact massive fibrosis, implying that it consisted of collagen impregnated with coal dust, has been challenged only during the last ten years. It was agreed that the best chance of obtaining more definite information was from a combined study of the biochemical, pathological, ultrastructural, and immunological features of a number of lungs containing these lesions. Six cases which were found to contain suitable material were studied. The preliminary results obtained suggest that collagen is present in the capsule of these lesions but that at the centre it is replaced by another insoluble protein or proteins which is probably stabilized by some form of cross-linking. This protein complex accounts for one-third of the weight of the lesions, the remaining two-thirds consisting of approximately equal amounts of mineral dusts and calcium phosphate. Serum proteins were also observed but their association with the lesions has yet to be determined. (+info)
Reading chest radiographs for pneumoconiosis by computer.
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Computer programs for measuring simple pneumoconiosis in radiographs are described and assessed. The 36 films studied had been read by 11 skilled human observers and a 'radiological score' of pneumoconiotic severity was therefore available for each film. The computer assigns to each square grid of side 3-6 mm a measure which reflects the unevenness of the density distribution in that grid. The 'computed score' is defined as the mean diversity over all relevant grids in both lung fields. On the set of 36 films the correlation between radiological score and computed score was 0-88. By contrast, the correlation between the score assigned by a single observer and the average of the scores assigned by the other 10 was in the range 0-95 to 0-98. The program can use the computed score to classify a film into one of the four major International Labour Office (ILO) U/C categories, the success rate of this process being 80% compared with those quoted by other workers in the range 45%-65%. If the films used in this study be typical, then the program described may form the basis of an automatic method for measuring pneumoconiosis in epidemiological work. (+info)
An unusual case of mixed-dust exposure involving a "noncommercial" asbestos.
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Our health center evaluated an individual for suspected pneumoconiosis, which had resulted from exposures in a foundry/metal reclamation facility. Appropriate consent forms were obtained for the procedures. Historically, individuals who work in foundries have been exposed to various types of dusts. The clinical findings in this case were consistent with silicosis with a suspicion of asbestos-induced changes as well. A sample from this individual, analyzed by electron microscopy, showed both classical and atypical ferruginous bodies. The uncoated fiber burden in this individual indicated an appreciable number of anthophyllite asbestos fibers. This finding, coupled with analysis of cores from ferruginous bodies and the presence of ferruginous bodies in areas of interstitial fibrosis, pathologically supported the diagnosis of asbestos-related disease. The unique factor associated with this case is that unlike in some settings in Finland where anthophyllite was mined and used commercially, this mineral fiber is not commonly found in commercially used asbestos products in the United States. Although the actual source of the asbestos exposure in this case is still being sought, it should be recognized that anthophyllite is a contaminant of many other minerals used in workplace environments, including foundries. The fiber burden indicates a unique type of exposure, differing from that usually construed as typical in occupational settings in the United States. (+info)
In vivo studies of man-made mineral fibers--fibrosis-related factors.
(14/300)
Pneumoconiosis that pursues a chronic course may result from repeated injury and repair caused by dust particles that remain in the lungs, leading to fibrosis. We will introduce in vivo studies concerning these processes using animals exposed to man-made mineral fibers and asbestos. We will report on whether there are developmental changes with the mineral fiber and animal model in proinflammatory cytokine, chemokine, free radicals, proteinase and other genes that lead to injury, as well as in genes that effect repair such as growth factor, and we will also report on the effects of surfactant protein and clara cell secretory protein on fibrosis. (+info)
Fifteen year follow-up study of VC and FEV1 in dust-exposed workers.
(15/300)
A baseline survey of 3457 male workers exposed to various forms of dust from 11 medical facilities throughout Japan was carried out in 1978 or 1979. We completed the present follow-up study 15 years later on 693 of the men. Vital capacity (VC) and forced expiratory volume in one second (FEV1) were analyzed as indices of lung function. We examined factors that affected both baseline and interval changes in VC and FEV1 by stepwise multiple regression analysis. In the cross-sectional data analysis of baseline, height, profusion rate (PR) and age were selected as predictor variables for VC and FEV1, additionally duration of working for FEV1. It indicated that baseline VC decreased by 84.0 ml with each increase in PR classification. Similarly, baseline FEV1 decreased by 146.6 ml with increasing PR. Baseline VC and FEV1 were both positively influenced by subject height. In the longitudinal analysis, baseline PR, age and smoking habits were selected for predictor variables for decline of VC and FEV1. It indicated a negative influence of baseline PR classification on VC and FEV1 changes (-5.0 and -7.5 ml/y, respectively). Smoking decreased VC and FEV1 by 6.1 and 5.8 ml/y, respectively. (+info)
SWORD '99: surveillance of work-related and occupational respiratory disease in the UK.
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Systematic reports from chest and occupational physicians under the SWORD and OPRA (Occupational Physicians Reporting Activity) surveillance schemes continue to provide a picture of the incidence of occupational respiratory disease in the UK. An estimated total of 4393 incident cases (comprising 4530 diagnoses) were reported during the 1999 calendar year, an increase of 1427 cases over the previous year. Benign pleural disease was the single most frequently reported condition (28% of all diagnoses reported). Occupational asthma cases (1168; 26%) remained high, as did mesothelioma (1032; 23%). Analysis of trends over the past 8 years shows an increase in mesothelioma cases, but little change in asthma. The annual incidence per 100,000 employed people, 1996-1999, for mesothelioma, lung cancer and pneumoconiosis was high amongst construction workers (28.7), miners and quarrymen (26.5), woodworkers (18.9) and gas, coal and chemical workers (15.2). Trends in mesothelioma incidence by birth cohort continue to show an increase in construction workers and a continuing decline in shipyard and insulation workers. The relative proportion of pneumoconiosis cases attributed to coal mining has fallen steadily in workers born since approximately 1920 and most cases are now in men who have been employed in quarrying and rock drilling. (+info)