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2.  Dust and Collagen Content of Lungs of Coal-Workers with Progressive Massive Fibrosis 
In order to test the silica theory of the origin of progressive massive fibrosis (P.M.F.) in coal-miners' pneumoconiosis, separate dust analyses have been made of the massive lesions and of the rest of the lung from 18 coal-workers with P.M.F. who had been employed in several coalfields. The dry weight of the massive lesions ranged from 5 to over 100 g. and the dust concentration in the P.M.F. lesions was on an average twice as high as in the rest of the lung. It was found that the quartz percentage of the lung dust was almost identical in the two samples from each lung (Table 3). The quartz content of the average lung dust (P.M.F. and “rest of lung”) of 32 cases of P.M.F. was compared with that of 58 cases of simple pneumoconiosis. The quartz content of the P.M.F. dust was slightly higher but, allowing for variable dust composition in different coalfields, the difference was not significant (Table 8). The silica theory of P.M.F. cannot be supported by this study.
Comparisons of the collagen content of the P.M.F. lesions and of the rest of the lung in 17 lungs and of lesions of P.M.F. and of simple pneumoconiosis in 31 and 27 lungs, respectively, showed no clear difference between any of the groups and surprisingly low values for the massive lesions. A possible way in which this result could be reconciled with the histopathological observations is suggested. One gram of coal-mine dust produced, on an average, 0·4 g. of dust produced between 2 and 7 g. of extra collagen.
extra collagen. In five silicotic lungs, where the lung dust contained 15 to 50% of free silica, 1 g. of dust produced between 2 and 7 g. of extra collagen.
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PMCID: PMC1039198  PMID: 14046154
3.  Dust and Fibrosis in the Lungs of Coal-Workers from the Wigan Area of Lancashire 
During the years 1953 to 1957 more than 1,000 lungs of coal-workers in the Wigan area were examined and compared with lungs from workers in South Wales. The Wigan lungs in general appeared to be less dusty and progressive massive fibrosis less frequent than in the South Wales lungs. Also, the more advanced cases of progressive massive fibrosis appeared to be of a silicotic type.
Of these lungs, 100 were selected for study of the relation of the type and severity of pneumoconiosis to right ventricular hypertrophy, using Gough-Wentworth sections. The remaining tissues from 47 of these lungs were used for an analysis of the content and composition of the dust and its relation to the grade of fibrosis. The average coal and quartz percentages of the dust from the lungs in the Wigan area were similar to previous findings in lungs from the Cumberland coalfield but differed from those in South Wales where the lung dust has a higher coal and a lower quartz percentage. Two possible explanations for this finding are discussed.
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PMCID: PMC1038314  PMID: 13990155
4.  The Relation Between Lung Dust and Lung Pathology in Pneumoconiosis* 
Methods of isolation and analysis of dust from pneumoconiotic lungs are reviewed, and the results of lung dust analyses for different forms of pneumoconiosis are presented.
A tentative classification separates beryllium, aluminium, abrasive fume, and asbestos, which cause interstitial or disseminated fibrosis from quartz, coal, haematite, talc, kaolin, and other dusts, which cause a nodular or focal fibrosis which may change to forms with massive lesions. The data suggest that in the first, but not in the second, group the dusts are relatively soluble; only in the second group do amounts of dust and severity of fibrosis go in parallel for a given form of pneumoconiosis. In classical silicosis the quartz percentage is higher and the amount of total dust much lower than in coal-miners' pneumoconiosis. Mixed forms of both groups occur, for instance, in diatomite workers. The need for more research, especially in the first group, is pointed out.
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PMCID: PMC1038077  PMID: 13727444
5.  Part I: General Observations 
Lungs from 45 coalworkers with simple pneumoconiosis have been compared with chest films obtained within two years of death. The carbon, quartz, mica, and kaolin content of the lungs was determined chemically. Large lung sections were used to assess the type and severity of emphysema and the presence of fibrous dust nodules. Histological sections were used to grade the amounts of reticulin and collagen in the simple dust foci. By using averages of four independent readings of each radiograph, subdivisions of the I.L.O. 1950 scale of categories were related to amounts of dust in the lungs.
It was found that the mean weight of total dust in the right lung was: category 0, 4·3 g.; category 1, 10·5 g.; category 2, 14·5 g.; category 3, 26·7 g.; and that the mineral and carbon contributed about equally to the radiological changes but, weight for weight, mineral contributed about nine times more than carbon. A physical explanation for this is suggested, in terms of relative absorptions of ϰ rays by carbon and mineral; the coefficients of absorption of the various dust components and “wet tissue” are compared at various wavelengths, and the effects on the radiograph are discussed. An explanation in terms of tissue reaction to dusts was also investigated but was not found to be plausible. “Mean ages of dust foci” (periods of dust retention) were studied from records of work underground, and compared with the radiological changes, the gradings for reticulin and collagen, and the presence of fibrous dust nodules. Observer variability in reading the ϰ-ray films was greater when fibrous dust nodules were present. The application of the results to the interpretation of studies of progression of simple pneumoconiosis judged from the radiograph is described.
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PMCID: PMC1038031  PMID: 14437667
6.  Pneumoconiosis in Carbon Electrode Makers 
In the absence of adequate preventive measures the manufacture of carbon electrodes is attended by a considerable dust hazard. The present paper is based on a study of the clinical, radiological, and pathological changes resulting from inhalation of this dust, which is derived from crushed coke and anthracite.
An account is given of the findings in a clinical survey of 15 men who had been employed for at least 10 years in manufacturing carbon electrodes. Four of these men were suffering from complicated and five from simple pneumoconiosis.
In addition, the findings in three necropsied cases (two complicated and one simple) are recorded in detail. Bacteriological examination of the lungs and analysis of the lung dust was carried out in the two cases of complicated pneumoconiosis.
It is shown that carbon electrode makers may develop simple pneumoconiosis with focal emphysema and that this may complicated by the development of massive fibrotic lesions. Both the simple and the complicated pneumoconiosis are indistinguishable from the corresponding conditions in other coalworkers.
Quartz was almost entirely absent from the lung dust of the two necropsied cases with massive fibrosis and in one of these cases virulent tubercle bacilli were shown. The significance of these findings is discussed in relation to the aetiology of progressive massive fibrosis. While it is evident that they are incompatible with the “silica” theory they provide some limited support for the “tuberculosis” theory.
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PMCID: PMC1037965  PMID: 13843110
7.  The Dust Content of the Lungs of Coal Workers from Cumberland 
The prevalence of pneumoconiosis varies from one coalfield to another. The present investigation arose from the observation that coal-miners' lungs from west Cumberland appeared much less black and had less coal in them than lungs from South Wales coal-miners.
Dust analyses were carried out on 33 lungs of coal workers from Cumberland which had been examined histologically and graded according to the classification of Belt and King (1945). No case of massive fibrosis (grade 4) occurred and this condition seems to be rare or absent in Cumberland. Compared with South Wales coal-miners' lungs, each histological grade of simple pneumoconiosis was on an average associated with less coal dust and more rock dust in Cumberland, and silicosis due to rock work in coal-mines appeared to be relatively more frequent.
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PMCID: PMC1037860  PMID: 13618519
11.  Pneumoconiosis of Kaolin Workers 
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PMCID: PMC1037711  PMID: 13364154

Results 1-19 (19)