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Query: UMLS:C0037116 (silicosis)
 1,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In recent years, with the aging of patients with pneumoconiosis, autoimmune diseases as a complication have been observed. One of the reasons for this may be that autoimmune diseases are prone to develop among the elderly. On the other hand, it has been reported that dust itself, such as silica for example, has adjuvant effect. A review of the recent literature published in Japan and abroad was made to clarify the relationship between pneumoconiosis and autoimmune diseases and the following results were obtained. 1) Disorders which accompany pneumoconiosis: Scleroderma, rheumatoid arthritis, systemic lupus erythematosus (SLE), and disorders of the kidney and liver have been reported. In Japan, about 30 cases of pneumoconiosis accompanied with autoimmune diseases have been reported. In many of the reports, patients with pneumoconiosis and scleroderma have a past history of exposure to silica. In both case studies and case control studies, patients with rheumatoid arthritis and history of silica exposure are prone to develop pneumoconiosis. 2) Immunological studies of patients with pneumoconiosis: As for humoral immunity, elevation of polyclonal gamma-globulin, especially IgG, has been often reported together with high positive rate of autoantibodies such as antinuclear antibodies. In cellular immunity, decreased delayed type skin reaction and decreased CD4/8 ratio have been reported. In human leukocyte antigen (HLA) typing the elevated frequency of DR4 has been reported. In the study of BAL increased production of superoxide anion O2- by alveolar macrophages has been observed. 3) EXPERIMENTAL STUDIES: Silica is well known for its toxicity to cells and also for its adjuvant effect. In the German Democratic Republic, patients with scleroderma and history of long term silica exposure are recognized as patients with occupational disease even though pneumoconiosis is not clearly demonstrated on X-ray film. It is difficult from this review to nrake a definite conclusion regarding the relation between silicosis and autoimmune diseases. There is a need to repeat this review of the literature on autoimmune diseases and pneumoconiosis in the near future.
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PMID:[Relationship between autoimmune diseases and pneumoconiosis]. 140 2

Silicosis and coal worker's pneumoconiosis (CWP) are two relatively common occupational diseases. Silicosis is the most common pneumoconiosis in the United States. It results from inhalation of the particulate form of quartz or other crystalline forms of silicon dioxide with a diameter of less than 5 micrograms. CWP is the result of inhalation of carbon particles. Pathologic features of the two diseases differ, yet their radiologic features are identical. Simple pneumoconiosis is characterized by multiple small rounded opacities of 1 to 5 mm in diameter and with a bias for the upper lung zones. Complicated pneumoconiosis results from confluence of small opacities into large opacities that form conglomerate masses or progressive massive fibrosis.
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PMID:Standard imaging in silicosis and coal worker's pneumoconiosis. 141 Mar 5

Scleroderma-like diseases can be induced by a number of chemical compounds, such as plastics, solvents and drugs. Contaminated rapeseed oil was the cause of the toxic oil syndrome and L-tryptophan induces the so-called eosinophilia-myalgia-syndrome. On the other hand, paraffin and silicon can trigger so-called adjuvant disease, while long-term exposure to silica can lead to idiopathic scleroderma (associated with silicosis in some cases). In addition to the clinical features, some pathogenetic data in the literature, such as genetic factors (HLA, chromosomal anomalies, enzyme deficiencies) and the metabolism of chlorinated ethylenes via reactive epoxide intermediate products, and our own findings are reported. Silica-induced scleroderma cannot be distinguished from the idiopathic form by epidemiological, clinical or immunological studies or by parameters referring to the blood vessels or collagen metabolism. In cell culture studies it has been shown that macrophages/monocytes release IL1, IL6 and TNF after ingestion of silica, which affects fibroblasts, T-helper cells and endothelial cells. Comparative results from the silicosis literature are reported. Finally, the possibly stimulating role of ionizing irradiation (uranium mining) in favouring the development of scleroderma is discussed.
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PMID:[Chemically-induced scleroderma]. 150 11

Estimation of the exposure to respirable dust in the workplace is an important aspect of industrial hygiene. We performed bronchoalveolar lavage (BAL) on 42 healthy nonindustrial control subjects and 44 workers in the Barre, Vermont granite industry to determine whether BAL materials reflected occupational exposure. The granite workers held jobs with a range of dust exposure intensities and had employment histories from 1 to 43 yr; 12 workers were retired. None of the workers had radiologic evidence of silicosis. The granite dust content of BAL materials was measured by enumerating the percentage of cells positive for particulates by polarized light microscopy, by analysis for silicon by scanning electron microscopy with energy-dispersive X-ray spectrometry, and by chemical analysis. Minerals were present in greater quantity in the BAL cells from granite workers than from nonindustrial control subjects. Polarized light microscopy was comparable in sensitivity, specificity, and overall accuracy to electron microscopy; chemical analysis was less accurate than either microscopic technique. Tobacco smoking did not interfere with the detection of the occupationally related minerals or influence the quantity of dust present. The mineral in BAL cells was partially related to the intensity of exposure within the granite industry and to the duration of employment, but there was great individual variation among subjects. Retirement led to a decrease in BAL mineral content, but substantial dust remained for many years.
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PMID:Effects of work exposure, retirement, and smoking on bronchoalveolar lavage measurements of lung dust in Vermont granite workers. 166 Feb 28

Alveolar epithelial cell injury and increased alveolar-capillary membrane permeability are important features of acute silicosis. To determine whether silica particles contribute directly to this increased permeability, we measured paracellular permeability of rat alveolar epithelium after exposure to silica, in vitro, using markers of the extracellular space. Silica (Minusil) markedly increased permeability in a dose- and time-dependent manner. This was not the result of cytolytic injury, because lactate dehydrogenase release from monolayers exposed to silica was not increased. Pretreatment of the silica with serum, charged dextrans, or aluminum sulfate blocked the increase in permeability. Scanning electron microscopy demonstrated adherence of the silica to the surface of the alveolar epithelial cells. Thus silica can directly increase permeability of alveolar epithelium.
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PMID:Silica directly increases permeability of alveolar epithelial cells. 169 64

In silicosis, alveolar macrophages (AM) are thought to induce chronic inflammation and fibrosis by release of cytokines. Rats were exposed to aerosols of alpha-quartz and examined 4 to 9 mo later for persistence of silica particles and release of tumor necrosis factor-alpha (TNF-alpha) from macrophages. Silica particles were detected in AM, lung parenchyma, and thoracic lymphoid organs, whereas extrathoracic lymphoid tissues and organs were free of the mineral. When AM were tested functionally, no spontaneous release of TNF-alpha was observed. However, upon in vitro stimulation of AM from silicotic rats with a low concentration of lipopolysaccharide (10 ng/ml), abundant TNF-alpha production was found that was higher and occurred more rapidly than with AM from sham-exposed animals. Peritoneal macrophages, which did not have contact with silica particles, displayed a similarly enhanced TNF-alpha release in response to low doses of lipopolysaccharide. These data demonstrate a state of systemic preactivation ("priming") of macrophages that supports the notion that silicosis is associated with a general immunostimulation.
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PMID:Systemic macrophage stimulation in rats with silicosis: enhanced release of tumor necrosis factor-alpha from alveolar and peritoneal macrophages. 191 Aug 24

A female patient, 60 years old, had been working as a flax scutcher for 20 years. Sectional investigation showed fissural thin-walled caverns in the superior lobe of the lung. Histologic investigation revealed granulomas of epithelioid and lymphoid cells in the lungs, pleura, spleen, and silicon dioxide crystals in the lung tissue. The clinical picture resulted from a combined action of flax dust particles and silicon dioxide, and was similar to those of allergic exogenous alveolitis and late stages of silicosis, which attributed it to the occupational diseases of flax scutchers.
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PMID:[Long-term consequences of lung injuries in flax scutchers]. 206 Aug 22

The Himalayan villages of Chuchot Shamma and Stok were surveyed because silicosis had been suspected from the radiographs of some of the inhabitants. The villages are agricultural, and Chuchot is exposed to frequent dust storms. Chest radiographs of villagers aged 50-62 were assessed blind by two independent observers using ILO criteria. In Chuchot five of seven men and all of the nine women examined showed varying grades of silicosis, compared with three of 13 men and seven of 11 women in Stok, which lies 300 metres higher and is exposed to fewer dust storms. The difference in prevalence of silicosis between the two villages was significant, as was the differences between men and women. Three patients from the village adjoining Chuchot were later found to have radiological evidence of progressive massive fibrosis. A necropsy on a man in a neighbouring village in the Indus valley showed classical silicosis in a hilar lymph node. Chemical analysis of the inorganic dust in the lung showed that 54.4% was elemental silicon [corrected]. This was similar to the silicon [corrected] content of dust samples collected from houses in Chuchot, which included particles of respirable size. X-ray microanalysis showed that quartz formed 16-21% of the inorganic lung dust. This study suggests that silicosis is common among the older inhabitants of these Himalayan villages. The dust exposure is clearly environmental and not industrial. Further studies are needed to define the extent and severity of silicosis in this community and to examine possible preventive measures.
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PMID:Silicosis in a Himalayan village population: role of environmental dust. 166 78

Out of 1,200 patients with irradiated bronchogenic carcinomas, 487 men worked as coal miners and were exposed to silicon dioxide dust. Of these 212 patients showed radiological signs of pulmonary silicosis. The patients with a bronchogenic carcinoma and silicosis showed no significant dependence upon the grade of silicosis or working time underground concerning histology, age at disease onset, or localization in comparison to people with a bronchogenic carcinoma but without silicosis. Seven patients suffered from cicatricial carcinomata, the tumorous features and means of formation of which are discussed in comparison to pathological-anatomical results.
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PMID:[Radiologic diagnosis of silicotic cicatricial cancer. Incidence and correlation with pathologic-anatomic results]. 216 Jun 71

Electron spin resonance (ESR) measurements show that grinding of quartz particles in air produces silicon-based (Si. and SiO.) radicals which decay with aging in air. ESR spin trapping measurements provide evidence for the generation of hydroxyl and possibly superoxide radicals from a suspension of fresh quartz particles. The hydroxyl radical generation potential of the fresh quartz particles decreases on storing in ambient air and on the addition of catalase, superoxide dismutase, desferroxamine, or DMSO. Silica-induced lipid peroxidation also decreases on storing the fresh particles in ambient air. These findings suggest that oxygenated radicals play a role in the biochemical mechanism of pneumoconiosis in general and acute silicosis in particular.
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PMID:ESR spin trapping and cytotoxicity investigations of freshly fractured quartz: mechanism of acute silicosis. 216 64


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