Biomedical subjects
Publications and source records attributed to R Vande Weyer.
Occupational asthma has been documented in electric arc welders exposed to manual metal arc welding on stainless steel. A subject is described who developed late and dual asthmatic reactions after occupational-type challenge exposure to gas metal arc welding on uncoated mild steel.
Latex gloves have been documented as causing rhinitis and asthma. Using inhalation challenges, we evaluated the bronchial response to hypoallergenic gloves in eight health care workers with latex-induced asthma. The subjects were exposed to the powdered latex gloves causing asthma at work and various brands of gloves with a lower protein content, either low-powdered, nonpowdered, or powdered. Exposure to hypoallergenic gloves resulted in the absence (in six subjects) or a significant reduction (in two subjects) of bronchial response. The effects of repeated exposure to hypoallergenic gloves was assessed in two subjects who did not demonstrate changes in peak expiratory flow rates and nonspecific bronchial responsiveness to histamine. This study on a limited number of patients suggests that the use of hypoallergenic gloves could be an effective means of reducing the risk of asthmatic reactions in health care workers with latex-induced asthma when complete avoidance cannot be achieved. The long-term effect of exposure as well as the widespread use of hypoallergenic gloves warrant further investigation on larger cohorts of subjects.
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We compared CT with chest radiography (CR) in the assessment of low grade coal worker's pneumoconiosis (CWP) in a population of 83 subjects. All subjects had a high-voltage p.a. CR, graded according to the ILO classification between 0/0 and 1/1, a conventional CT (CCT) using contiguous 1-cm-thick sections on the entire thorax and a set of 10 high-resolution CT (HRCT) images. CR and CT were separately read by consensus by 2 teams of 2 trained readers. CR was coded 0/0 in 9 subjects; 0/1 in 31; 1/0 in 28; 1/1 in 15. Among these groups of patients, micronodules were detected by CT in respectively 2 (22%), 14 (45%), 17 (61%) and 10 (67%) patients. In all groups, micronodules were more often detected by CT when the opacities detected on CR were scored as rounded (p, q) than irregular (s, t). Among the patients graded 0/0 or 0/1, CT showed micronodules in 40%. By contrast, among the patients graded 1/0 or 1/1, CT did not show micronodules in 37%, but revealed in numerous patients that opacities detected on CR were related to bronchiectasis and/or emphysema only. Comparative analysis of HRCT and CCT showed that both techniques are complementary and proved the usefulness of CCT in the detection or confirmation of low profusion of micronodules.
To compare the value of conventional CT (CCT) and high-resolution CT (HRCT) to detect benign asbestos-related diseases, 159 exposed workers with a normal chest radiography were imaged by both techniques. Pleural plaques were detected in a total of 59 cases (37.1%). Ten cases (16.9%) were detected by CCT only and one case (1.7%) by HRCT only. Pulmonary lesions compatible with parenchymal asbestosis were detected by HRCT in 20 cases, whereas CCT showed abnormalities in 45% of these. Rounded atelectasis was equally recognized by both techniques. The results confirm that in a subject with a normal chest radiography, HRCT is a better diagnostic tool to demonstrate lesions of asbestosis. On the other hand, HRCT is insufficient to exclude the presence of pleural plaques. When HRCT does not reveal pleural abnormalities, CCT should be performed.
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Diagnosis of pneumoconiosis was made in 2 dental technicians presenting with interstitial lung disease. The occupational origin of inhaled dust was confirmed by mineralogic analyses, which disclosed mainly large amounts of chromium-cobalt-molybdenum particles originating from Vitallium prostheses, but also showed abrasives (silica and silicon carbide) and asbestos in 1 patient. The presence of Vitallium and its chemical stability in bronchoalveolar lavage and lung several years after cessation of exposure confirm the resistance of this alloy to corrosion by body fluids. This contrasts with the high solubility of cobalt described in cobalt or hard metal disease. We suggest that dental technician's pneumoconiosis is a complex pneumoconiosis distinct from silicosis, asbestosis, or hard metal disease and that Cr-Co-Mo alloys play a role in its pathogenesis.
The exposure of asbestos was studied in 31 cases of mesothelioma from case histories and by microscopic mineralogical analysis of the broncho-alveolar lavage fluid (BAL) (31 cases) and of pulmonary tissue (5 cases). When definite exposure had occurred the lavage contained asbestos bodies in every case, except one patient with severe airflow obstruction. The most positive lavages, probably reflecting exposure to industrial amphiboles, were found in patients presenting with radiological evidence of asbestosis. Two patients had positive lavages 50 years after exposure had ceased. The lavage confirmed exposure in 6 out of 11 suspected cases and revealed contamination by asbestos in a further 4 cases, in a group of 6 not known to have been exposed. In 19.3% of cases there was a low concentration of asbestos bodies (less than 1AB/ml of BAL), comparable to what is found in 16.2% of controls from an urban population. An analysis of lung tissue confirmed massive exposure (greater than 20 000 AB/g) in two cases and in particular revealed a significant dust load (greater than 250 AB/g) in patients presenting with a weak positive BAL. Thus it seems that all the positive results should be taken into account. Of the 31 cases, 8 had a BAL without asbestos bodies. These were either mesotheliomas not linked to the inhalation of asbestos, or were the result of false negatives on account of artefacts related either to the BAL technique itself or linked to the technique of mineral analysis. Indeed the microscopic counts of asbestos bodies probably underestimate certain exposures, notably environmental exposure to chrysotile.
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This study was carried out between 1973 and 1982 on the proportional mortality by lung cancer of a group of workers living either in Brussells or in Wallonia and receiving compensation for silicosis or anthrasilicosis. The majority of patients suffered from anthrasilicosis (more than 96%) and had been exposed to the risk of pneumoconiosis in one of the four coal fields in Wallonia. If, in 13,822 deaths studied the proportional mortality from lung cancer had grown by 0.56% per year reaching 3.7% in 1973 and 9.3% in 1982, it remained below that for a similar Belgian population matched for age and sex. No correlation could be found between the occurrence of this tumour and one or other radiological category as defined by the international classification of pneumoconiosis in 1980. In addition the severity of pneumoconiosis, either from a radiological or functional view, hardly had any influence on the genesis of lung cancer. Finally, the localisation of the tumour and the different histological types do not differ from that reported in the literature among the general population. On the other hand a significant rise in proportional mortality from lung cancer between 1973 and 1982 (p less than 0.001) seemed to be related to two factors, smoking habitis (89.1% of subjects dying from lung cancer were smokers at the moment of death against 68.5% of smokers among other causes of death), and above all the progressive aging of the population of pneumoconioties receiving compensation, the cross section 50-69 rose from 53.17% in 1973 to 73.8% in 1982.
The problems encountered in diagnosing the rare types of pneumoconiosis ( silicatosis other than asbestosis, aluminosis and hard metals fibrosis), result from the difficulties in realising a good occupational anamnese and from the disease pattern by itself. The classical examinations, (X-rays of the thorax and lung function measurements), are not able to detect the cause of these diseases, which are fundamentally characterised by an absence of specificity. These last years, new methods of diagnoses (angiotensin converting enzyme, gallium scan, transbronchial biopsies, mineralogical, cytological and histological examinations of the lung tissues and of the bronchial alveolar lavage) were developed and progressively introduced in the daily practice in pneumology. Only the examination of lung biopsies and of the products of bronchial alveolar lavage, in particular the mineralogical examinations, may usefully orientate the diagnosis. The bronchial alveolar lavage has the advantage of an easy repetition and of a small invasive character. Moreover this technique is of a rather low financial cost. However the results of these examinations must be interpreted with the greatest caution, in function of the complete medical and occupational data. The experience following more than 500 BAL shows that the discovery of talc and kaolin is very significant for an exposition since these minerals were never observed among not exposed subjects. The evidence of these minerals argues also for the diagnosis of talcosis or kaolinosis if there are radiological lesions that are compatible with these diseases. On the other hand a recent study suggests that the identification of multinuclear macrophages and of tungsten and/of tantalum in the bronchial alveolar lavage is pathognomonic of the pathology of the hard metals.
Asbestos bodies (AB) were counted in bronchoalveolar lavage (BAL) fluid from 62 patients with suspected asbestos related diseases, 2 patients with known exposure to asbestos but without related disease, and 40 control subjects. BAL fluid contained AB in all patients with obvious exposure (28 of 28), including the 2 without related disease, in most patients with suspected exposure (26 of 28), as well as in 5 of 8 patients without known exposure but with suspicion of asbestos related disease (mesothelioma or pleural plaques). Among the 40 control subjects, the results in 5 were positive but to a low degree (less than 1 AB/ml of fluid). Quantitative analysis correlated with the type of disease: AB counts were higher in patients with interstitial lung disease than in those with benign (p less than 0.02) or malignant (p less than 0.01) pleural disease. Only 9 of 13 patients with mesothelioma had a positive lavage. In conclusion, the finding of AB in BAL fluid correlates with the occupational risk and can disclose unknown exposure better than a questionnaire, but a positive lavage is not a proof of disease. Quantitative differences in AB counts suggest a different pathogenesis for pleural and parenchymal disease.
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