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Biomedical subjects

N B Pride

Publications and source records attributed to N B Pride.

At least 127 records · Page 7Linked to original sources

Asthma in Asian immigrants.

Adult Asian immigrants to the United Kingdom attending an asthma clinic have been compared with a control group of non-immigrant Caucasian asthmatic patients of similar age distribution. The Asian immigrants had a later age of onset of asthma than their non-immigrant controls. Comparison with studies of asthmatic patients in India suggests that this may be an intrinsic ethnic difference but an effect of migration in early adult life is not excluded. Despite a later age of onset, the frequency of positive skin prick tests to common allergens was similar in the immigrant and control groups and 71% of the Asians had positive reactions to the house dust mite. Most other clinical features, the variability of airways obstruction and the requirements for treatment showed no significant differences between the two groups.

Adolescent↗

Lung distensibility and airway function in intermediate alpha 1-antitrypsin deficiency (Pi MZ).

We examined the role of intermediate alpha 1-antitrypsin deficiency in predisposing to abnormalities of lung distensibility and airway function in 20 heterozygotes (Pi MZ) who were individually matched with a control Pi M subject of similar age, height, and smoking habits drawn from the same male, working population. There were no significant differences between the heterozygotes and their controls in the results of spirometry, maximum expiratory flow-volume curves (breathing air), single breath nitrogen test, arterialised capillary blood oxygen pressure, or single breath carbon monoxide transfer. Additional studies were made in 12 of the pairs of Pi MZ and Pi M subjects. Comparison of maximum expiratory flow-volume curves breathing air and 80% helium-20% oxygen showed no differences between the Pi MZ and Pi M subjects. Although airway function was similar in the two groups, four of 12 Pi MZ subjects showed abnormalities of the pressure-volume curve of the lung (reduction in lung recoil pressure, abnormal shape factor, increase in functional residual capacity). Abnormalities of washout of a helium-sulphur hexafluoride gas mixture, of a type previously described as characteristic of emphysema, were found in two of the men with abnormal pressure-volume curves. The results suggest that Pi MZ subjects have an increased susceptibility to alveolar abnormalities without increased abnormalities of airway function; this may explain the increased frequency of emphysema at necropsy despite many studies showing no predisposition to abnormal airway function in life. The functional changes we observed would be unlikely to cause symptoms. The risk of disablement from chronic lung disease appears to be only slightly enhanced by intermediate alpha 1-antitrypsin deficiency.

Adult↗

A double-blind trial of oral aminophylline (Phyllocontin Continus tablets) in airflow obstruction: preliminary communication.

Twenty-two patients with reversible airflow obstruction were entered into a double-blind crossover trial of Phyllocontin Continus tablets and placebo to assess the additional benefit of the controlled-release aminophylline preparation when added to the patients' medication. Most patients were taking inhaled or oral steroids in addition to inhaled beta-sympathomimetics throughout the trial. The dosage of Phyllocontin tablets was adjusted in a pre-trial study to provide serum theophylline levels in the accepted therapeutic range of 10--20 mg/l. In the seventeen patients who completed the 8-week study a small, but significant, increase in both the patients' own recordings of PEFR and weekly clinic measurements of FEV1 was seen whilst on the active drug. Ten patients had improvement in FEV1 greater than 200 ml. Eleven patients recorded subjective improvement on the active drug and five out of ten patients who used inhaled beta-sympathomimetics p.r.n. showed a reduction in their usage of greater than 10%. Side-effects were reported by twelve patients.

Adult↗

Use of exercise challenge to investigate possible tolerance to beta-adrenoceptor stimulation in asthma.

The effect of prolonged salbutamol administration on beta-adrenoceptor function in asthma has been examined. Six adult patients received salbutamol tablets (16 mg daily) for between 4 and 20 weeks and six adolescents received salbutamol aerosol (800 microgram daily) for 2--5 weeks. Before and after the treatment period the acute bronchodilator response to inhaled salbutamol and the ability of inhaled salbutamol to protect against exercise-induced asthma were examined. Lymphocyte beta-adrenoceptor function was also measured in the patients on tablet therapy. Inhaled salbutamol was less effective in protecting against exercise-induced asthma at the end of the treatment period in the patients who had received tablet therapy, but otherwise there was no significant change in beta-receptor function of either airways or lymphocytes. This apparent loss of efficacy of inhaled salbutamol in the prevention of exercise-induced asthma in some subjects, even when its acute bronchodilator effect is preserved, might reflect differences in the susceptibility of different beta-adrenoceptors to desensitization after prolonged stimulation: its clinical importance remains uncertain.

Adolescent↗

Ventilation and perfusion scans in the preoperative assessment of bronchial carcinoma.

Ventilation (krypton -81m) and perfusion (technetium -99m) lung scans were obtained in a consecutive series of 21 patients shortly before thoracotomy for proven or suspected carcinoma of the bronchus. In most patients ventilation and perfusion were impaired equally and the scan abnormality corresponded to the bronchoscopic and radiological findings. Unexpectedly large defects in the perfusion scan were seen in three patients, all of whom had extensive neoplastic involvement of the mediastinum at thoracotomy, but 11 other patients had mediastinal involvement which was not suspected from the scan. Ventilation scanning was useful in the prediction of postoperative ventilatory capacity in two patients who underwent pneumonectomy. We conclude that ventilation and perfusion scans are not sensitive indicators of neoplastic involvement of the mediastinum but they are valuable for the prediction of postoperative lung function.

Adult↗

Pulmonary mechanics in patients with respiratory muscle weakness.

Pulmonary mechanics and respiratory muscle pressures were studied in 7 patients with severe respiratory muscle weakness. Minimal pleural pressures were grossly abnormal and showed little variation with lung volume. Both the maximal transpulmonary pressure and static expiratory compliance were low; therefore, the pressure-volume curves of the lungs resembled those obtained after strapping the chest in normal subjects. The low compliance may result from either microatelectasis or a generalized alteration in alveolar elastic properties and is probably a major determinant of both the total lung capacity and the breathing pattern of patients with neuromuscular disease. Airway and gas exchange function were less abnormal than the elastic properties of the lungs.

Adult↗

Pulmonary mechanics in fibrosing alveolitis: the effects of lung shrinkage.

Pulmonary and airway mechanics were studied in 8 patients with severe fibrosing alveolitis. In this disease, the number of functioning alveoli is probably considerably decreased, but static compliance was low even when related to the decreased lung volume. Lung recoil pressures toward full inflation were high but were not increased at and below functional residual capacity. Airway function was broadly normal for lung recoil pressure but supernormal for absolute lung volume. Analysis of model pressure-volume and maximal flow-volume curves showed that (1) these features could be produced simply by replacement of some units by indistensible fibrous tissue and retention of normal function of the surviving alveoli, respiratory muscles, chest wall, and airways; (2) increased lung tissue volume may prevent an increase in lung recoil pressures in the lower part of the vital capacity; and (3) the decreased lung volume could result in a decrease in upstream conductance without structural change in the airways. Measurement of lung compliance, even when corrected for the decreased lung volumes, may not distinguish between loss of units (lung "shrinkage") and abnormal distensibility of the functioning alveoli, but the latter is likely if maximal expiratory flow is excessive in relation to the lung volume expressed as per cent vital capacity.

Adult↗