Incidence Of Pneumoconiosis Research Articles

The epidemiology and clinical management of chronic obstructive pulmonary disease in Singapore.

The epidemiology and clinical management of chronic obstructive pulmonary disease in Singapore.

Characterization of alveolar macrophage eicosanoid production in a non-human primate model of mineral dust exposure

The relative activation of eicosanoid production which results from the exposure of the alveolar macrophage (AM) to mineral dusts is thought to be a key factor in the pathophysiology of occupational lung disease. We compared in vitro basal and silica-stimulated production of prostaglandin E 2 (PGE 2) and thromboxane A 2 (TXA 2) by AM from normal humans and non-human primates (Macaca nemistrina). In addition, we instilled mineral dusts directly into one lung of the non-human primate and evaluated AM eicosanoid production at two week intervals following dust instillation. Unstimulated AM from humans produce more PGE 2 and TXA 2 than do AM from M. nemistrina. However, in vitro exposure of AM from both species to silica dust produced a qualitatively similar increase in TXA 2 production accompanied by no change in PGE 2 production. Sequential analysis of AM eicosanoid production following a single bolus exposure to bituminous or anthracite coal dusts, titanium dioxide (TiO 2) dust or crystalline silica showed marked variability among individual non-human primates in qualitative and quantitative aspects of dust-induced eicosanoid production. However, the rank order of potency of the different dusts (silica > anthracite > bituminous) correlated with epidemiological evidence relating the type of dust mined to the incidence of pneumoconiosis. These studies suggest that the non-human primate may serve as a model for the study of both the role of eicosanoids in the etiology of dust-induced occupational lung disease and the biochemical basis for individual variability in the response of lung cells to mineral dust exposure.

PNEUMOCONIOSIS IN POTTERY WORKERS AND ITS TRENDS IN NORTH STAFFORDSHIRE FROM THE POINT OF VIEW OF THE MEDICAL BOARDING CENTRE (RESPIRATORY DISEASES), STOKE-ON-TRENT

Classification of pottery workers' pneumoconiosis and the procedure followed for claims to disablement benefit for this condition have been outlined. Review of the newly diagnosed cases of pneumoconiosis in pottery workers in North Staffordshire as experienced by the Medical Boarding Centre (Respiratory Diseases), Stoke-on-Trent, show that the number of such cases has dropped from the peaks of nearly 300 cases per year in the mid-1950s to about 10 cases per year in the last 12 years. The percentage of people aged 60 and above among the newly diagnosed cases has increased from 35% in the 1960s to about 70% in the 1980s. Only a minority of cases has been diagnosed following exposure under 20 years and most described exposure for over 30 years. As a point of interest, age at death of not strictly comparable groups of pottery workers at different times over the last 100 years has been compared. The longevity, probably not surprisingly, appears to have improved considerably during that period. Although our data do not denote the true incidence of pneumoconiosis in pottery workers in North Staffordshire perhaps it may be concluded that our figures do point to a declining incidence of this condition.

Pathology of Common Murres and Cassin's Auklets exposed to oil

The histopathology of diving seabirds exposed to oil is described. Cassins Auklets (Ptychoramphus aleuticus) were experimentally exposed to weathered Santa Barbara Channel (CA) crude oil by external application to the breast plumage or wings. Beached Common Murres (Uria aalge) were recovered from an accidental oil spill of bunker C fuel oil. Exposed birds exhibited hepatocellular dissociation and hemosiderosis, renal tubular necrosis, and hemolytic anemia. Both unexposed and exposed birds exhibited numerous gastrointestinal lesions and parasites making interpretation of oil damage effects to the gastrointestinal system difficult. Burrow nesting auklets had a high incidence of pneumoconiosis while cliff nesting murres had no particulate inclusions on lungs. The results describe the extent of pathology to be expected in wild, free living seabirds.

A Prediction of the Incidence of Pneumoconiosis in Japan

A Prediction of the Incidence of Pneumoconiosis in Japan

粉じん作業離職後のじん肺

In Japan, there were about 12, 000 workers awarded compensations for total disability due to pneumoconiosis in December 1977. The number of new cases showed to be on the increase year by year, especially from the year 1971 onward. The purpose of this study was to interpret more accurately characteristics and factors of the incidence of pneumoconiosis. Questionnaires were mailed to 3, 400 cases awarded compensations for total disability due to pneumoconiosis out of which 2, 991 were completed and returned. The results were as follows: 1) Of the 2, 991 cases, 47% were certified at some time after having left dusty occupations. Perecentage of the cases by succeeding periods of year certified showed to increase, 17% from September 1955 to March 1960, 52% from April 1960 to March 1978 and 69% from April 1978 to June 1979. 2) The length of the period from the separation from dusty occupations to the certification for compensation showed to increase. Percentage of the cases certified after ten years and over from the separation was 2% from September 1955 to March 1960, 21% from April 1960 to March 1978 and 33% from April 1978 to June 1979. 3) Mean age of the cases certified after having left dusty occupations was higher than that of the cases certified within the period employment of the dusty occupations. 4) Of 1, 402 cases certified after having left dusty occupations, 49% were coal workers, 28% metal miners and 10% tunnel workers and those in construction. 5) Mean age of the coal workers certified was the highest among those 1, 402 certified cases. Regarding the reasons of separation of coal workers who were certified after having left, discharge was 40%, age-limit 28%, aggravation of physical conditions 19% and other 13%. 6) Mean age of the tunnel workers and those in construction who were certified was the lowest and the mean duration of the service was the shortest among those 1, 402 certified cases. Regarding the reasons of separation of these workers, aggravation of physical condition was 57%, discharge 14%, age-limit 0%, transference 16% and others 13%.

LUNG CANCER IN A FLUORSPAR MINING COMMUNITY. II. PREVALENCE OF RESPIRATORY SYMPTOMS AND DISABILITY.

A survey of respiratory symptoms, lung function tests, and chest radiography was carried out among the fluorspar miners of St. Lawrence, Newfoundland, in whom the incidence of carcinoma of the lung (De Villiers and Windish, 1964) had previously been shown to be 25 times greater than for the rest of the province. The incidence of pneumoconiosis among the exposed population was low (1·93%) and the incidence of `chronic bronchitis9 comparable to that reported for miners elsewhere, enabling one to dismiss these as a relevant factor in the high incidence of carcinoma. The relevance of smoking is less easy to assess in these miners, among whom there are few non-smokers and many heavy smokers. Extrapolation from the data of Doll and Hill (1956) suggests, however, that the prevalence of heavy smoking among the miners cannot be the sole factor responsible for the higher incidence of carcinoma compared with the rest of Newfoundland, but it might well be a contributory one. It appears therefore that the main factor causing the high incidence of carcinoma among these miners was the high level of radioactivity in the air and water in the mines (De Villiers and Windish, 1964). The reduction in lung function tests appeared to be more closely related to the presence of bronchitis than to dust exposure, but the incidence of chronic bronchitis was apparently higher in men exposed for any length of time to dust risk than in men with insignificant exposure.

Experimental studies on the relative importance of concentration and duration of exposure to dust inhalation.

In a previous paper (Wright, 1953a) reasons have been given for believing that the best measure of the amount of inhaled dust that will be retained in the lungs is the product concentration x time. This conclusion was based on theoretical considerations of the mechanism of dust inhalation and retention, and on the experience of workers who have studied the correlation between dust exposure and the incidence of pneumoconiosis in men. It has fre quently been suggested that the question should be studied experimentally, but no such experiments appear to have been recorded. Although the experi mental approach to the question seems at first sight to be an obvious one, there are serious technical difficulties in exposing animals for sufficiently long periods to controlled dust concentrations, and in measuring their exposure. In this paper the way in which these difficulties have been overcome will be described, and an account given of three experiments designed to determine the relative importance of time and concentration in dust exposure.

Pneumoconiosis in foundry workers

Summary 1. The historical aspects of pneumoconiosis in foundry workers are briefly reviewed. 2. Foundry processes are described. 3. The pathology of foundry workers' lungs is discussed in detail with special reference to the distinction between classical silicosis and mixed dust fibrosis. Pneumoconiosis (silicosis and/or mixed dust fibrosis) is the main cause of death in foundry workers. 4. Other causes of death include tuberculosis, carcinoma of bronchus, pneumonia, bronchiectasis and coronary thrombosis. Chronic bronchitis and emphysema are commonly found. Emphysema is bullous, generalised or focal. Focal emphysema is more often seen with mixed dust fibrosis than with classical silicosis. 5. Reference is made to chemical analyses of the mineral content of foundry workers' lungs. 6. The X-ray appearances of silicosis and mixed dust fibrosis are described. 7. The incidence of pneumoconiosis is shown to be higher in fettling (or castings cleaning) shops than in other foundry workrooms, and higher in steel than in iron fettling shops. By contrast iron moulding shops show a higher incidence of pneumoconiosis than steel moulding shops. 8. The prevention of pneumoconiosis in foundry works is briefly discussed.

A method of relating the incidence of pneumoconiosis to airborne dust exposure.

One of the tasks of the Pneumoconiosis Research Unit has been to try to relate the incidence of pneumoconiosis to the environment in which it has developed. In surveys in coal-mines, the incidence of pneumoconiosis among the miners has been measured by x-ray examinations ; in addition, detailed industrial histories and measurements of the miners' dust exposure have been collected. In this paper we discuss the method of inter-relating the information obtained.

Chronic Pulmonary Disease in South Wales Coalminers.

This report on the occurrence and nature of pneumoconiosis in coal miners is the result of a study begun in 1937 and carried through despite the exigencies of war. Its appearance at this time can be credited to the British quality of seeing a job through, while its tremendous thoroughness and its scientific caution in drawing conclusions must be credited to the able collaborators who made and wrote up the medical survey and the pathologic report. The incidence of pneumoconiosis is studied in relation to mining conditions, the type of coal mined, the kind and the duration of work done, the incidence of tuberculous infection and the degree of disability. A prenodular stage of reticulation is described both roentgenologically and pathologically. The illustrations of roentgen changes, showing both whole chests and detailed enlargements of limited areas, are extraordinarily good. There is an excellent bibliography. In addition to those persons with

Physical type in pneumoconiosis

When a number of persons is exposed to a particular pneumoconiosis-producing dust for the same period under apparently similar conditions, some of them develop the disease while others escape. It is possible that the less easily affected group comprises merely those who by chance or through some inborn or acquired local physical difference, e.g. nose-breathing, receive smaller doses of the noxious dust into the lungs. It is also possible that they are a selected group of peculiar constitutional type. The latter view has been accepted by some authorities and used in practice in selecting entrants to the mining industry, on the ground that by excluding certain anthropometric types the incidence of pneumoconiosis, or of pneumoconiosis complicated by tuberculosis, would thereby be reduced, though no adequate statistical data have so far been published to support this hypothesis.

The X-ray Aspects of Pneumoconiosis

THE early detection and correct classification of pneumoconiosis is still one of the difficult problems in diagnostic roentgenology. It may, therefore, be of interest to summarize recent observations concerning the diagnosis and differential diagnosis of the disease, and to discuss its classification from the point of view of the clinical radiologist. Pneumoconiosis has been defined as the series of injurious changes, fibrotic and usually progressive in character, produced in the lungs by the inhalation of unusual quantities of certain dusts. While dust containing particles of silica is the chief offender, it is now known that certain silicates, coal dust, and other dusts also produce changes. Some workers believe that sericite, hydrous aluminum silicate, rather than silica, SiO2, is the principal noxious agent, but agreement is far from complete on this point; Cummins (1) recently observed that “silicosis” may yet be found to be “silicatosis.” The majority favor silica as the cause and believe that it produces specific changes in the cells of the lung either on account of its colloidal properties or by acting as a protoplasmic poison (16). In spite of modern preventive methods in industry, it is alleged that the incidence of pneumoconiosis is increasing. It is quite certain that the industrial production of fine silica powder, now an important constituent of many chemical compounds in daily use, is on the increase. Lanza and Vane (7) estimate that over half a million workers in the United States are exposed to the silica-dust hazard (and that the mortality from tuberculosis is appreciably affected by such). Technic of Roentgen Examination The diagnosis of pneumoconiosis is based on (1) the history, (2) the clinical findings, and (3) the roentgen findings. The weakest link in the chain is the clinical examination and the strongest the roentgen evidence. The diagnosis requires the intelligent correlation of all three types of data, and, since it constitutes the strongest link, the most thorough type of roentgen examination. This examination should include (a) a careful fluoroscopic examination, to aid in the detection of complicating emphysema, pleural adhesions, cavities, and right-sided cardiac enlargement, and (b) clear sharp teleroentgenograms made in 1∕20 of a second or less. The latter should consist of stereoscopic anterior and plain lateral films, as a minimum procedure; the importance of intensifying screens with good contact cannot be over-emphasized. Re-examination at the end of four weeks is frequently necessary to exclude the existence of complicating acute inflammatory processes which may exaggerate a mild fibrosis at the initial examination.