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Biomedical subjects

F D Pooley

Publications and source records attributed to F D Pooley.

At least 55 records · Page 3Linked to original sources
PubMed1980

The consequences of exposure to asbestos dust in a wartime gas-mask factory.

This further study of wartime gas-mask workers who were exposed to asbestos dust has shown that among those who worked with crocidolite there is a considerable excess of cases of mesothelioma, a more modest excess of bronchial carcinoma, but no excess of any other type of malignant disease. A dose-response relationship is established in the mesothelioma and bronchial carcinoma patients. It is not possible to base any conclusions on the limited data available for the small number of people exposed to chrysotile for a maximum period of five months. We believe that the identification and measurement of fibres in autoptic lung tissue from patients with accurately known occupational histories of asbestos dust exposure is useful, and a similar study on a population exclusively exposed to chrysotile would be of considerable interest.

Asbestos↗
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

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↗
PubMed1980

Identification and quantification of asbestos fibres in human tissues.

The examination of three dust preparations by two independent laboratories using analytical transmission microscopic techniques has shown that comparable results can be produced. Further interlaboratory collaboration is required, however, to clarify and improve the results that can be obtained. Those areas that require further investigation are data interpretation from energy-dispersive X-ray analysis equipment and counting procedures. The results that have been obtained so far by interlaboratory collaboration are very encouraging, and it is hoped that such joint efforts will be expanded in the future.

Asbestos↗
PubMed1979

Fiber dimensions and aspect ratio of crocidolite, chrysotile and amosite particles detected in lung tissue specimens.

Chrysotile, amosite and crocidolite fibers detected in autopsy tissue specimens from cases of mesothelioma and controls have been characterized by particle length, diameter and aspect ratio using a transmission electron microscope. The pooled information from such specimens reveals that the fibers of each mineral type detected in biological material have very different physical characteristics although in all samples fibers less than 5 microns in length are predominant by number while fibers over 25 microns in length are found very infrequently. Chrysotile fibers on average appear as the shortest fibers with the most fine diameter distribution, amosite fibers are on average the longest with the most coarse diameter distribution, crocidolite fibers on average have dimensions which are intermediate between both chrysotile and amosite. The percentage number of fibers of chrysotile, amosite and crocidolite detected with an aspect ratio less than or equal to 10 were 31.7%, 24.2% and 18.5% respectively.

Asbestos↗
PubMed1975

Chemical and physical properties of British talc powders.

An examination of bulk talc samples imported into Great Britain has shown that they are extremely variable in their talc mineral content. Major contaminating minerals present with the talc are chlorite, carbonates and quartz. The chemistry of samples examined varied with their mineralogical content which also accounted for observed differences in particle morphology. Tremolite fibres were found in three samples, one of which contained the mineral as a major phase. No other varieties of asbestos were detected.

Asbestos↗
PubMed1975

Animal experiments with talc.

Italian talc has been tested on rats using three routes, intra-pleural inoculation, inhalation and ingestion. Groups exposed to superfine chrysotile asbestos and untreated controls were included for comparison. In all the experiments animals were allowed to live out their lives. The intra-pleural inoculation of talc produced no mesotheliomas in contrast to eighteen produced by the chrysotile asbestos. After ingestion, one leiomyosarcoma occurred with Italian talc and one with chrysotile asbestos. Whether these tumours are a consequence of the feeding is uncertain. The inhalation studies demonstrated that with equal dosage, talc can produce a similar amount of fibrosis as asbestos. However, the chrysotile exposed rats developed lung adenomas, adenomatosis and an adenocarcinoma, whereas the only lung tumour seen in animals exposed to talc was a small adenoma, which may have been an incidental finding.

Animals↗
PubMed1974

Electron microscopical investigation of asbestos fibers.

Examination of asbestos fibers by electron microscopical techniques enables the observer to distinguish among the fiber types by morphological and structural characteristics. Chrysotile asbestos fibers are composed of bundles of fibrils. Fibers are often curvilinear with splayed ends. Individual fibrils consist of a central capillary defined by an electron dense crystalline wall. With increasing time of electron bombardment, the capillary wall decreases in thickness, deforms, and is encapsulated in an electron translucent material. The change in electron opacity is considered to be a product of structural disruption brought about by dehydroxylation due to electron radiation. A well recognized sequential deformation pattern may be used for identification purposes.Amphibole fibers tend to be straight, splintery, and electron-opaque, although curved fibers are occasionally observed. Diffraction contrast figures are visible as dark bands moving parallel and at right angles to the fiber axis. Crocidolite forms the shortest and thinnest fibers, followed in size by amosite and anthophyllite. Size distribution characteristics of the amphibole fiber types are different. The selected area electron diffraction pattern for chrysotile is unique. Reflections range in forms from streaked to arcuate. Reflection intensity and shape are related to the degree of openness of the fiber bundle and the extent of physical degradation of the fiber. The amphibole asbestos fibers possess diffraction patterns having similar characteristics prohibiting individual identification. Microchemical analysis is required for identification in such cases.A discussion of the industrial hygiene threshold limit values for ampliphibole asbestos fibers is presented. The discussion is based on their differing size distribution characteristics.

Air Pollutants, Occupational↗