The relationship between change in airway calibre and change in airway reactivity after administration of bronchodilator drugs has been investigated by comparing the effect of increasing doses ofinhaled salbutamol and ipratropium bromide on the forced expiratory volume in one second (FEV,), specific airways conductance (sGaw), and the dose of histamine causing a 20% fall in FEV, (PD20) in six subjects with mild asthma. On each of 10 occasions measurements were made of baseline FEV,, sGaw, and PD20 after 15 minutes' rest, and followed one hour later, when the FEV, had returned to baseline, by a single nebulised dose of salbutamol (placebo, 5, 30, 200 and 1000 pg) or ipratropium (placebo, 5, 30, 200 and 1000 jig) given in random order. Measurements of FEV,, sGaw, and PD20 were repeated 15 minutes after salbutamol and 40 minutes after ipratropium. Salbutamol and ipratropium caused a similar dose related increase in FEV, and sGaw, with a mean increase after the highest doses of0-76 and 0-69 litres for FEV1 and 1-15 and 0-96 s-kPa-1 for sGaw. Salbutamol also caused a dose related increase in PD20 to a maximum of 2-87 (95% confidence interval 2-18-3-55) doubling doses of histamine after the 1000 pg dose, but ipratropium bromide caused no significant change in PD20 (maximum increase 0-24 doubling doses, 95% confidence interval -0-73 to 1 22).Thus bronchodilatation after salbutamol was associated with a significantly greater change in airway reactivity than a similar amount of bronchodilatation after ipratropium bromide. This study shows that the relation between change in airway reactivity and bronchodilatation is different for two drugs with different mechanisms of action, suggesting that change in airway calibre is not a major determinant of change in airway reactivity with bronchodilator drugs.Several studies have confirmed an association between increased airway reactivity and diminished airway calibre in subjects with airflow obstruction'" but the cause of the association is not clear. There are reasons to expect that an increase in airway reactivity would lead to increased airflow obstruction, and vice versa that an increase in airflow obstruction would increase airway reactivity, by a combination of mechanisms.9' Alternatively, both airflow obstruction and increased airway reactivity may occur as a result of a common underlying disease process.Bronchodilator drugs such as ,B agonists, antimuscarinic agents, and methylxanthines have been shown to cause a decrease in airway reactivity in conjunction

SUMMARY The accuracy of diagnosis in 656 patients with the four common histopathological types of primary lung cancer has been assessed by comparing the cell type diagnosis made on cytological and histological investigation with that determined by examination of the surgically resected or necropsy specimen. The accuracy of diagnosis achieved by cytological examination of sputum and bronchial aspirate, and by bronchial biopsy histology was over 85%. The least accurate diagnostic procedure was percutaneous needle biopsy (62%). Squamous and small cell tumours were accurately diagnosed by all four investigations but errors were made in the diagnosis of large cell and adenocarcinomas. Nearly half the number of patients (43%) with large cell carcinoma were later reclassified as having squamous carcinoma and of the patients with adenocarcinoma 32% had been predicted to be squamous and 18% large cell carcinoma. We consider such quality control of pretreatment diagnosis mandatory in management of individual patients and before enrolment in clinical trials.In 1979 a study was reported from Papworth Hospital, Cambridge which examined the accuracy of diagnosis of cell type in patients with primary lung cancer.' The presumptive cell type as predicted by cytology and biopsy techniques was compared with the true histological cell type as determined by histological examination of tumour tissue obtained at surgical resection or necropsy. The results indicated that the true cell type was most accurately predicted by sputum cytology (88 Y.), closely followed by bronchial aspiration (84%) and bronchial biopsy (80 %). The least accurate procedure was percutaneous needle biopsy (48 %). Diagnostic accuracy was highest in patients with squamous cell carcinoma while particular difficulty was experienced in diagnosis of patients with adenocarcinoma.Inevitably, with such a study limited to a four-year period in a single hospital, the number of patients in each histological group was relatively small. We have therefore undertaken a larger study of 673 patients with confirmed lung cancer seen at two centres, Papworth Hospital, Cambridge and Brompton Hospital, London and this includes the results of the original work from Papworth.

No abstract

No abstract