Sixty-four subjects with asbestos-related diffuse pleural thickening attending the London Medical Boarding Centre for Respiratory Diseases (formerly, the Central Pneumoconiosis Panel) were studied to investigate symptomatology, lung function, and radiographic change over an average period of 8 to 9 yr. Chest pain was a common symptom, occurring in over half of the subjects. Approximately one-third of the subjects had a history of pleurisy or pleural effusion. Full long function, available in all cases, showed a highly significant decrement (p < 0.001) compared with predicted values in all variables except gas transfer coefficient (Kco) at initial presentation, consistent with a restrictive ventilatory defect. Longitudinal lung function, available over a mean period of 8.9 yr in 36 subjects, showed a significant decrement above that predicted in FEV1 and FVC only (p < 0.05). Decreases in other parameters were observed, although statistical significance was not achieved. Radiographic score increased with time but there was no correlation between change in lung function and increasing radiographic score, probably reflecting the initial severity of the disease in subjects studied. These observations confirm an initial decrement in lung function in diffuse pleural thickening which is followed by comparatively little change over time.

Rheumatoid arthritis is associated with a number of pleuropulmonary disorders. A retrospective study of the frequency of rheumatoid disease in patients with bronchiectasis and pulmonary fibrosis was performed. The results suggest that the frequency of bronchiectasis and rheumatoid disease is similar to that of the well established, but rare, association between pulmonary fibrosis and rheumatoid arthritis. We therefore suggest that bronchiectasis should be remembered as a pulmonary association of rheumatoid disease which occurs as commonly as pulmonary fibrosis.

Male infertility may be linked to respiratory tract disease in conditions such as cystic fibrosis and Kartagener's syndrome. Young's syndrome constitutes another such link, in which bronchiectasis is found in association with obstructive azoospermia and normal testicular function. We have studied 34 infertile men with mechanical azoospermia and appropriate control subjects to assess the number of patients with respiratory tract disease and the type and frequency of such disorders. Nineteen patients (59%) had grossly abnormal sinus radiographs compared with six controls (18%) (p < 0.01) and 19 (56%-NS) gave a history of sinusitis; of these, six (18%) had had sinus operations (p < 0.01). Eleven patients (32%) had histories of repeated otitis media, of whom two had had mastoid operations. Twelve (35%) had chronic bronchitis, of whom three were non-smokers. Ten other patients had bronchiectasis (p < 0.001) and three of

ABSTRACr This study was designed to standardise a progressive exercise test for the assessment of change in carbon monoxide transfer coefficient (Kco) with exercise and to examine the variation between subjects and the reproducibility within subjects. Normal subjects exercised on a bicycle ergometer while ventilation, heart rate, and expired gas concentrations were recorded continuously. Preliminary studies showed that reduction of the breath hold time to six seconds made measurements of Kco during heavy exercise more comfortable without affecting the result. When Kco was measured immediately after exercise it was lower than when measured during exercise. Kco was measured in 50 normal subjects at rest and at three different work loads maintained for three minutes with a pause of five minutes between each. The relationships between Kco and both oxygen consumption and work load were linear in all subjects but the relationship between Kco and heart rate was distorted by high resting heart rates in some subjects. The mean slope of the relationship between Kco and oxygen consumption (Vo2) was steeper in women than in men (mean slopes 0*627 and 0*348 mmol min-' kPa-' 1-' per I min-' respectively), and the same was true for the relationship between Kco and work rate. The heart rate rose more steeply in relation to V02 in women, so that the relationship of Kco to heart rate was similar in men and women (mean slope 0 01 mmol min-' kPa-' 1-' per beat min-'). Repeat studies on five occasions in five individuals gave coefficients of variation for the slopes of the relationships between Kco and Vo2, work rate, and heart rate of 5-10%.In her original studies of carbon monoxide diffusing capacity (DLCO), Krogh showed that the measurement increased during muscular work.' Ogilvie and colleagues,2 when developing the single breath technique now in common use, observed a linear relationship between DLCO and energy expended on exercise. Ingram and colleagues' recently studied the change of transfer coefficient (Kco) with heart rate during progressive exercise and found it to be a more sensitive index of abnormal pulmonary function than resting measurements in patients with pulmonary sarcoidosis.We have attempted to standardise a progressive exercise test to measure change in Kco on exercise, examining the variation between subjects and the reproducibility within subjects.

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