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The importance of non-malignant pleural fibrosis in asbestosis in relation to respiratory function is still open to debate because of the differing results obtained in studies of different population groups. In the present study we selected 50 subjects with occupational exposure to asbestos presenting mono- or bilateral pleural fibrosis at X-ray but without lung impairment. Each subject underwent bronchial lavage and ventilatory function tests. The subjects were divided into 4 groups on the basis of the degree of pleural alterations according to the ILO Classification of Pneumoconioses. The results revealed that the mean values of CV and FEV1 in each group were within physiological limits. Moreover, analysis of the type of lung function showed a normal situation in 64% and restricted function in 28% of the cases. The prevalence of the latter finding was not correlated to the severity of pleural fibrosis in the various groups. Also, comparison between severity of pleural fibrosis and number of asbestos bodies/ml of BAL liquid on the one hand and frequency of alveolitis on the other did not reveal any relationship. Therefore, the onset of pleural fibrosis appears to be independent of the quantity of inhaled asbestos fibres and due to different mechanisms from those leading to lung fibrosis. In practice, a correct interpretation of the presence of pleural fibrosis from a clinical and prognostic viewpoint also requires other investigations such as BAL and a complete respiratory function study.

Although the risks connected with occupational exposure to asbestos and its numerous industrial uses are widely known, it still happens that instances of exposure with high potential risk are discovered. A detailed study of a worker suffering from silicosis and asbestosis who had worked for many years in a firm dealing with the recovery and re-use of used jute sacks also containing asbestos, revealed the existence of a real asbestosis risk in the firm, with the result that other workers in the same firm were studied. A total of 22 subjects were studied, 17 of whom also underwent bronchoalveolar lavage (BAL) and determination of the cellular composition of the recovery liquid in order to establish the presence of asbestous alveolitis. The age of the subjects ranged between 39 and 75 years (x = 56.36), length of service in the firm ranged between 2 and 18 years (x = 9.27), time between start of exposure and clinical examination varied between 29 and 50 years (x = 40.27). The 22 subjects were divided into 3 groups on the basis of the radiological examinations: 1) 8 cases were negative (36.36%); 2) 8 cases had pleural alterations only (36.36%); 3) 6 cases had interstitial lung disease (with and without pleural lesions) (27.27%). Of the 17 subjects who underwent BAL, 7 were in the first group, 7 in the second and 3 in the third. Among these 17 subjects BAL showed absence of alveolitis in all subjects of the first group, diagnosis of alveolitis in only some of the second group, and in all of the third group.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary circulation hemodynamics was studied by microcatheterization at rest and during exercise in 16 workers with asbestosis. There was pulmonary arterial hypertension owing to increased total pulmonary resistance even in the early stages of pneumoconiosis, sometimes without impairment of lung function. In two cases, a partial reduction in pulmonary hypertension and total pulmonary resistance was obtained with aminophylline. The pathogenesis of pulmonary circulation impairment has been attributed in previous work to periarteriolar fibrosis originating in the lymphatic vessels, until now insufficiently emphasized as the anatomical basis of these physiological alterations.

In a 37 years-old female worker, who had undergone surgical excision of a segment of the right lower lobe for a chronic aspecific pleuropneumonitis, the histological examination of the excised lung tissue showed asbestos alveolitis with diffuse interstitial fibrosis, and multiple granulomata containing talc particles. An investigation at the work site showed that the worker had been engaged for 22 years in dusting salami with a mixture of rice flour and talc contaminated with chrysotile asbestos. Thirteen work-mates engaged in the same job were studied. In two of them, with chest X-rays negative for pneumoconiosis, a functional ventilatory impairment, restrictive in type, associated with a reduced pulmonary diffusion of gases, was demonstrated. In these two cases, bronchoalveolar lavage showed signs of severe exposure to asbestos (which at TEM evaluation resulted to be amphibolic) talc and other fibres, with presence of iron-laden macrophages, indicators of haemorrhagic alveolitis. Moreover, in one of them, a severe macrophagic-lymphocytic alveolitis, with inverted T helper/T suppressor ratio, was presented, possible expression of a hypersensitivity pulmonary reaction. Taking into consideration the length and modality of work, with exposure to talc powder contaminated with asbestos, for the three cases the diagnosis of "pre-radiologic talcosis-asbestosis" was made. Since the occupational risk was not known in this industry, no ambient and personal preventive and protective measures had been taken; anyway, such type of work has now been stopped. The exposed workers shall be kept under control in the future for surveillance directed towards early diagnosis of possible further asbestos effects.