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

A histological study was made of the pulmonary vasculature in two cases of haematite lung. Between fibrotic nodules in the lung the muscular pulmonary arteries showed the development of longitudinal muscle in the intima, a change thought to be associated with stretch and distortion of these vessels. In some arteries this muscular layer in the intima showed secondary fibrosis. No muscularized pulmonary arterioles were seen, indicating an absence of constriction of the terminal portions of the pulmonary arterial tree. Pulmonary arteries in fibrotic areas had become progressively engulfed by the fibrous tissue. The occlusive and obliterative vascular changes in 'haematite lung' are in reality those of silicosis which are brought about by the inhalation of silica particles with the iron sesquioxide. The only feature peculiar to haematite lung is the intense accumulation of iron-containing dust in and around the pulmonary blood vessels.
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PMID:The pulmonary vasculature in haematite lung. 64 43

A percutaneous needle biopsy was performed with a TruCut needle on 41 patients with suspected pneumoconiosis. Patients selected for biopsy tended to have brief or unusual dust exposure, as well as questionable radiographic opacities. Sixteen had been exposed to asbestos, 13 to silica and 12 to mixed dust containing quartz, coal, iron, asbestos and talc. All patients in the asbestos group and most in the other two groups had a reduced transfer factor. Most patients in the asbestos group and about 25% of the other patients had restrictive ventilatory impairment. Chest radiographs were assessed according to standard films of the ILO U/C International Classification (International Labour Office, 1972). In 25 patients radiographic opacities were absent or acanty (categories 0--1/1). The dominant radiographic feature of many patients exposed to asbestos was a ground-glass appearance or a bilateral elevation of the diaphragm, or both, features difficult to assess according to the ILO U/C scheme. Most histological changes were those usually seen in pneumoconiosis. However, in only two patients with silicosis were silicotic nodules detected. The specimens of seven patients showed a granulomatous inflammation. The severity of alveolar wall involvement correlated well with the transfer factor value but poorly with radiographic changes. The profusion of radiographic opacities also correlated poorly with functional impairment. As a diagnostic tool the needle biopsy was valuable in asbestosis and slightly less so in mixed-dust fibrosis. The biopsy specimens showed changes compatible with asbestosis in 75% of the suspected cases and in 86% of those in which asbestosis was the final diagnosis. In the mixed-dust group pneumoconiosis was confirmed in 67% and 80%, respectively. In the diagnosis of silicosis an open biopsy is probably more reliable than a percutaneous one, particularly if radiographic changes are minimal. Histological changes in the needle biopsy specimen were compatible with silicosis in only 36% of the suspected cases and in 63% of those in which the final diagnosis was silicosis.
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PMID:TruCutR needle biopsy in asbestosis and silicosis: correlation of histological changes with radiographic changes and pulmonary function in 41 patients. 73 36

As part of a larger study relating to silica exposure, silicosis, and lung cancer mortality in Chinese mine and factory workers, 1936 old posterior-anterior chest X-rays were re-interpreted according to the 1986 Chinese Roentgenodiagnostic Criteria of pneumoconioses. Each film was independently read by three individuals from a panel of eleven radiologists, and this reading was compared to the original one. Subsequent to the independent readings, a groups of three readers interpreted the films together, called the consensus readings. Comparisons were made by Chinese stage of pneumoconiosis. For the entire cohort, there was a crude agreement of 57.4% between the old and the new interpretations. Agreement within one step of full agreement was 92.5%. The interpretations done by median reading and by consensus were very similar. In general, there was a tendency for the old readings to be slightly higher compared to the new interpretations. This tendency was most marked in the tin mines, followed in decreasing order by the iron/copper mines, the potteries, and the tungsten mines. The agreement between the old and new interpretations is felt to be satisfactory.
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PMID:A comparison of radiographic interpretation of silica exposed workers using the 1963 and the 1986 Chinese roentgenodiagnostic criteria of pneumoconioses. 133 88

Slate is a metamorphic rock comprising silica, aluminum silicates, and small amounts of chlorite, hematite, magnetite, and various carbonates. In the United States slate is quarried in Virginia, Pennsylvania, New York, and Vermont. Workers are exposed during mining and processing of the slate and in crushing mills that prepare gravel. We have conducted detailed mineralogic and pathologic studies on the lungs of 12 workers who developed a pneumoconiosis while employed in the quarries of west central Vermont and adjacent areas of New York. Perivascular and peribronchial lesions accompanied by interstitial fibrosis and macules were scattered diffusely in the lungs. The lesions were associated with a variable number of silicotic nodules. Scanning electron microscopy combined with energy-dispersive x-ray spectrometry demonstrated aluminum and silicon-containing particles with variable cationic constituents and silicon alone in a pattern typical of free crystalline quartz. By x-ray diffraction analysis the majority of the mineral particulates were free crystalline quartz and muscovite, an aluminum silicate in the mica group of minerals. Slateworkers are exposed to respirable airborne dust that has the capacity to produce a pneumoconiosis that differs from classic silicosis.
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PMID:Slateworker's pneumoconiosis. 139 38

The association between silicosis and lung cancer mortality was estimated in 9,912 (369 silicotics and 9,543 nonsilicotics) white male metal miners. These miners were examined by the U.S. Public Health Service during 1959-1961 and were followed through 1975. Miners were excluded from this study if they were employed in a mine during 1959-1961 that used diesel equipment underground. The ores that were mined consisted of copper, lead-zinc, iron, mercury, lead silver, gold and gold-silver, tungsten, and molybenum. The standardized mortality ratio (SMR, U.S. white male rates) for lung cancer was 1.73 (95% CI: .94-2.90) in silicotics and 1.18 (95% CI: .98-1.42) in nonsilicotics. Additionally, SMRs were higher in silicotics than in nonsilicotics, even in most subgroups stratified by cigarette smoking habit, type of ore mined, years of service in an underground job, radon exposure group, or year of hire. When lung cancer mortality between silicotics and nonsilicotics was compared, the age-adjusted rate ratio (95% CI) was 1.56 (.91-2.68), and the age- and smoking-adjusted rate ratio was 1.96 (.98-3.67). Corresponding figures for miners who were employed in mines with low levels of radon exposure were 1.90 (.98-3.67) and 2.59 (1.44-4.68), respectively. These findings indicate that lung cancer mortality risk was increased in silicotics, and this probably did not result from chance or bias. However, confounding from radon exposure could not be ruled out. The findings indicate that further follow-up of this cohort is needed.
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PMID:Silicosis and lung cancer in U.S. metal miners. 200 98

The mortality risk of iron ore (haematite) miners between 1970 and 1982 was investigated in a retrospective cohort study of workers from two mines, Longyan and Taochong, in China. The cohort was limited to men and consisted of 5406 underground miners and 1038 unexposed surface workers. Among the 490 underground miners who died, 205 (42%) died of silicosis and silicotuberculosis and 98 (20%) of cancer, including 29 cases (5.9%) of lung cancer. The study found an excess risk of non-malignant respiratory disease and of lung cancer among haematite miners. The standardised mortality ratio for lung cancer compared with nationwide male population rates was significantly raised (SMR = 3.7), especially for those miners who were first employed underground before mechanical ventilation and wet drilling were introduced (SMR = 4.8); with jobs involving heavy exposure to dust, radon, and radon daughters (SMR = 4.2); with a history of silicosis (SMR = 5.3); and with silicotuberculosis (SMR = 6.6). No excess risk of lung cancer was observed in unexposed workers (SMR = 1.2). Among current smokers, the risk of lung cancer increased with the level of exposure to dust. The mortality from all cancer, stomach, liver, and oesophageal cancer was not raised among underground miners. An excess risk of lung cancer among underground mine workers which could not be attributed solely to tobacco use was associated with working conditions underground, especially with exposure to dust and radon gas and with the presence of non-malignant respiratory disease. Because of an overlap of exposures to dust and radon daughters, the independent effects of these factors could not be evaluated.
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PMID:Mortality experience of haematite mine workers in China. 232 25

The mortality risk of nonmalignant respiratory disease among hematite workers in the Longyan and Taochong mines of China was investigated in a retrospective cohort study covering the period 1970-1982. The cohort was limited to men and consisted of 5406 underground miners, of whom 1335 (25%) were diagnosed as having silicosis. Among those with silicosis, 560 (42%) were diagnosed as having silicotuberculosis. Among the 490 underground miners who died, 278 (57%) died of nonmalignant respiratory disease. The relative risk for death due to nonmalignant respiratory disease for stage III silicotics compared to nonsilicotics was almost 100-fold. High dust exposure was associated with a statistically significant increase in risk of death due to nonmalignant respiratory disease (relative risk 5.3). The relative risk associated with jobs with high dust exposure before the introduction of industrial hygiene controls was 7.7, and the corresponding value for after their introduction was 2.3. There is a need for continued close monitoring of industrial hygiene in these mines.
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PMID:Nonmalignant respiratory disease among hematite mine workers in China. 279 17

Recent epidemiologic studies have suggested that some workers exposed to inorganic dusts develop air-flow obstruction independent of or greater than that produced by cigarette smoke; the morphologic basis of this effect is unknown. To investigate this problem, we administered saline alone, 10 mg iron oxide (an inert dust), or 10 or 30 mg of quartz to rats by intratracheal instillation. Animals were killed after 30 days, and pulmonary function and morphologic changes were examined. The iron oxide group was similar to the saline control group in all functional and morphometric parameters. However, both quartz-exposed groups showed evidence of air-flow obstruction, with more severe abnormalities in the high dose group. These findings correlated with morphometric observations of emphysema and thickened airway walls, with changes again more severe in the high dose group. Early silicotic nodules were also present in the latter animals. We conclude that in addition to the classic lesions of nodular silicosis, quartz can produce morphologic and functional changes of air-flow obstruction; no such changes are seen with iron oxide. These observations may explain the air-flow obstruction seen in workers exposed to mineral dusts.
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PMID:Quartz but not iron oxide causes air-flow obstruction, emphysema, and small airways lesions in the rat. 284 35

The conditions which might favour development of the fibrotic or the lipid component of the pulmonary reaction to inhaled quartz were examined in rats. Smaller particle size and freedom from surface contamination by amorphous silica or iron oxide, status of the animals whether specific pathogen-free or conventional, and the resistance of cell membranes to damage appeared to bear on fibrogenesis. Increased membrane stability by treatment with polyvinylpyridine-N-oxide abolished not only the fibrosis but also the response of type II cells and hence lipidosis. The rate and intensity of quartz deposition may also affect the response, a low concentration inhaled over a long period favouring nodulation. No other manipulations, environmental or pharmacological, succeeded in inhibiting lipidosis to the benefit of fibrosis. Guinea pigs, however, behaved differently, their reaction being characterized by massive alveolar accumulation of dust-bearing macrophages and type II cell hyperplasia but not by lipidosis. The species variation is unexplained but macrophage predominance may represent a phase that later transforms to lipidosis. The experimental findings may have implications for forms of pneumoconiosis other than silicosis.
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PMID:Determinants of pulmonary fibrosis and lipidosis in the silica model. 302 27

A case of accelerated silicosis in a shotblaster in an iron foundry is described. The clinical course was notable for the rapid progression of cor pulmonale and the appearance of clubbing over a period of 2-3 months. Radiographic and pathological features atypical of the more chronic forms of the disease are described. The importance of the occupational history and the need for the strictest respiratory protection in such work are illustrated. Stringent control of this type of operation is urgently needed.
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PMID:Accelerated silicosis in a foundry shotblaster. A case report. 334 Sep 19


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