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Biomedical subjects

J C Wagner

Publications and source records attributed to J C Wagner.

At least 73 records · Page 4Linked to original sources
PubMed1982

Post-mortem study of emphysema in coalworkers and non-coalworkers.

A post-mortem survey of emphysema in coalworkers and non-coalworkers was carried out in men aged 50-70 years dying of ischaemic heart disease (IHD). It was determined that in such men selection for necropsy was similar in coalworkers and non-coalworkers. All lungs were examined in a standard way and the amounts of centrilobular and panacinar emphysema were scored on numerical scales. Emphysema in men dying of IHD was significantly more frequent in coalworkers than in non-coalworkers even after age and smoking habits were accounted for by stratification. In the coalworkers, the severity of emphysema was related to the amount of dust in simple foci in the lungs. Because both groups were selected similarly from their parent populations the relative frequency of emphysema found in this study reflects that in the whole populations of coalworkers and non-coalworkers in the study area and confirms an excess of emphysema in coalworkers. This excess is likely to be due to occupational factors.

Aged↗
PubMed1982

Biological effects of tremolite.

Tremolite is an amphibole which has been implicated in a variety of disease patterns in different parts of the world. It occurs in a number of phases, which are chemically identical but have specific physical characteristics. In an attempt to clarify the epidemiological findings, tremolite fibres of 3 specific forms--A, B and C--were characterized and studied for biological activity by: (i) in vivo intrapleural injection of rats (2 separate experiments--1 with poor survival). (ii) in vitro enzyme release from mouse peritoneal macrophages (iii) in vitro giant-cell formation in A549 cultures (iv) in vitro cytotoxicity for V79-4 cells. Sample C, which contained more long thin fibres than A and B, was alone in producing mesotheliomas. C, but not A or B, induced LDH and B-glucuronidase enzyme release, and induced giant cells. A was not cytotoxic, B moderately cytotoxic and C as highly cytotoxic as UICC crocidolite. The in vivo studies were marred by being split between 2 experiments, of which the second had poor survival. We are aware of the weakness of our in vivo data, but as Tremolite C was being considered for commercial use on the European market we felt it timely to submit our findings for publication.

Animals↗
PubMed1982

Presence of fibronectin in pneumoconiotic lesions.

During the last 10 years our investigations have confirmed that collagen is not the major protein material in the lesions of progressive massive fibrosis of coal workers. In previous studies it was demonstrated that a substance similar in composition to fibrin was an important component in these masses. We report immunohistochemical studies on the lungs of seven coalworkers which show that the complex extracellular material in six of the lesions of massive fibrosis contains fibronectin. Preliminary observations indicate that fibronectin is also present in the lesions of silicosis and asbestosis.

Fibronectins↗
PubMed1981

Preliminary observations of the effect of inhalation of PVC in man and experimental animals.

Attention has been focussed, both in man and experimental animals, on the effects of inhalation of the gas monomer, vinyl chloride. Recently, note is being taken of the possible effects of the inhalation of the polymer in man. The particles in question are those produced commercially as paste polymer or dispersion polymer or having an average diameter of 0.15 micrometers, and accounting for more than 10% of the production in Britain. There are now strict regulations for the control of the monomer gas, but the particles are regarded as nuisance dust and their emission is not covered by specific legislation. Our studies on rats, where both inhalation and implantation methods of exposure have been used, and examination of tissue from human cases exposed to paste polymers, indicate that these small particles can only be regarded as evidence of exposure, and on present evidence there is no indication of causation of significant pulmonary disease. Techniques have been developed by which these particles can be demonstrated in ordinary histological preparations and by transmission electron microscopy.

Aerosols↗
PubMed1980

Silica-induced malignant histiocytic lymphoma: incidence linked with strain of rat and type of silica.

It has already been established that a single intrapleural inoculation of crystalline silica (quartz) produces malignant lymphomas of histiocytic type (MLHT) in Wistar-derived rats. It has now been shown that after treatment with Min-U-Sil, rats of the Alderley Park strain have a tumour incidence of 35%, whereas the incidence in Agus rats is 5% and in PVG 8%. There was also a significant difference in the incidence of MLHT caused by injecting different samples of crystalline silica, particularly of tridymite. There was correlation between cytotoxicity to mouse peritoneal macrophages and tumour incidence, except for one dust (DQ12). Zeta potential, number of particles and their size range were considered, but the incidence does not show a clear correlation with these measurements. The results are discussed.

Animals↗
PubMed1980

Treatments affecting the rate of asbestos-induced mesotheliomas.

256 Wistar rats received a single injection into the right pleural cavity of UICC crocidolite in order to induce mesotheliomas. They were then given right intrapleural injectons of BCG, crystalline silica, talc, carrageenan or saline (as a control). There was no significant change in the mesothelioma rate in the rats exposed to BCG, silica or talc, but there was a 3-fold increase in mesothelioma incidence in the group injected with carrageenan.

Animals↗
PubMed1980

The pathology and mineral content of lungs in cases of mesothelioma in the United Kingdom in 1976.

A study was made of 93 cases of mesothelioma who died in 1976 in the United Kingdom. Lung tissue was available for mineral fibre analysis from 86 of these cases, and also from 29 cases of cerebrovascular disease and 27 cases of bronchial carcinoma, matched for place of death, age and sex with the mesothelioma cases. It was observed that: (1) mesothelioma patients had more amphibole fibres in their lungs than did control cases; (2) chrysotile fibres were not present in greater numbers in the mesothelioma patients than in the control cases; (3) four of the mesothelioma cases had no amphibole fibres in their lungs; two of these had chrysotile fibres, and the other two had no asbestos fibres; and (4) 30 cases of mesothelioma had no chrysotile fibres in their lungs.

Adult↗
PubMed1980

A study by electron microscopy of the effects of chrysotile and man-made mineral fibres on rat lungs.

The effects of inhalation of rock wool, coated and uncoated glass wool, glass fibre and UICC chrysotile B on the ultrastructure of the rat lung have been investigated. All fibres produced focal fibrosis, type II cell proliferation, an accumulation of cellular debris and lipid material and hyperplasia of both alveolar cells and cells lining the terminal airways. The fibrosis was more marked following inhalation of chrysotile than after exposure to man-made mineral fibre.

Animals↗
PubMed1980

The comparative effects of three chrysotiles by injection and inhalation in rats.

Three samples of chrysotile, UICC Canadian chrysotile, a grade 7 Canadian chrysotile and a super fine sample (SFA) also from a Canadian mine, were compared in animal experiments using rats of the Wistar strain. All the materials contained impurities. The average length and diameter of the fibres contained in the UICC chrysotile cloud were less than for the other two chrysotiles, but the higher fibre count meant that the UICC cloud contained more fibres of all lengths. In the first experiment, groups of 48 rats were injected intrapleurally with 20 mg of respirable dust. Mesotheliomas occurred with all samples; 18 with SFA, 13 with grade 7, and five with UICC chrysotile. In the second experiment, rats were exposed to a respirable cloud of about 1 mg/m3 for 35 hours a week. Groups of 48 rats were exposed for three months, 24 for six months and 24 for 12 months. Malignant lung tumours occurred with all the dusts; 10 with UICC chrysotile, 4 with SFA, and 1 with grade 7. However, only one of these tumours, obtained with SFA, was a mesothelioma.

Animals↗