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Biomedical subjects

C R McGavin

Publications and source records attributed to C R McGavin.

17 recordsLinked to original sources
PubMed1991

The ultrasound appearance of asbestos-related pleural plaques.

Twenty-five patients with a history of asbestos exposure and radiological evidence of pleural plaques were examined by ultrasound (US). Non-calcified pleural plaque appeared as a regular area of echo-poor tissue which was well defined adjacent to the diaphragm or lateral chest wall, and varied in thickness from 5 mm to 12 mm. Calcified plaques had echogenic and irregular anterior margins with acoustic shadowing beyond. They were associated with characteristic comet tail and straight line artefact.

Asbestos↗
PubMed1991

The radiological appearances of 'Q' fever pneumonia.

The chest film findings in a series of 21 cases of serologically proven 'Q' fever with radiological evidence of pneumonia were reviewed retrospectively. Segmental opacities which were slow to clear, often with loss of volume and sometimes lobar consolidation, were the most usual findings. Lesions were occasionally multiple and sometimes became rounded during resolution. The appearances were not considered sufficiently distinctive to allow the diagnosis to be made in the acute phase of the illness, although the appearance of round pneumonias which are slow to resolve should alert the radiologist to this possible diagnosis. The findings are discussed in relation to previously reported series.

Adolescent↗
PubMed1988

The distribution of pulmonary shadowing in farmer's lung.

Reports of the radiological features in farmer's lung are inconsistent. We have reviewed clinical and radiological findings in eight patients with farmer's lung in the acute and sub-acute phases. In the acute phase the main feature is transient widespread diffuse shadowing of air space consolidation. In the sub-acute phase, the predominant feature is fine nodular shadowing tending to involve either the upper half or upper two-thirds of the lungs with relative sparing of the basal segments. This is in accordance with both the pathophysiological behaviour of the inhaled particulate antigen and the subsequent distribution of pulmonary changes in chronic farmer's lung.

Acute Disease↗
PubMed1984

Diffuse pleural thickening in asbestos workers: disability and lung function abnormalities.

Data from 37 asbestos workers with diffuse pleural fibrosis have been analysed. None had radiological evidence of asbestosis or physiological evidence of airflow obstruction. Forty per cent had breathlessness of MRC grade 3 or higher. Vital capacity was significantly lower in the subjects in the higher grades of breathlessness and in those with greater radiographic pleural abnormality. No relationship was demonstrated between dust exposure and either radiographic abnormality or grade of breathlessness. Diffuse pleural thickening, particularly when extensive and bilateral, causes functional impairment and disability.

Asbestos↗
PubMed1982

Diaphragmatic breathing training and walking performance in chronic airways obstruction.

Eight patients with chronic obstructive bronchitis and moderate disability entered a pilot study of the effects of controlled diaphragmatic breathing. They received three weeks of placebo physiotherapy (shoulder exercises) followed by three weeks of instruction on controlled diaphragmatic breathing. No beneficial effects were observed on exercise performance or the perceived strain of exercise.

Aged↗
PubMed1980

Corticosteroids in chronic airways obstruction: can the patient's assessment be ignored?

In a study to examine the methods of assessing the response of patients with chronic airways obstruction to corticosteroids, 20 patients received a week of placebo tablets, followed by three weeks of prednisolone 30 mg daily. Subjective benefit was assessed by a visual analogue scale (VAS), and objective changes by spirometry and an exercise test. Significant increases in FEV1 and in exercise performance were observed after steroid therapy. Changes in FVC correlated both with VAS score and with changes in exercise performance. Changes in FEV1 correlated with neither. The good correlation between the changes in a ventilatory function test (the FVC) and the patients' assessments of the drug suggests that the non-specific euphoriant effect of steroids does not eclipse their specific action on ventilatory function. Assessment of benefit should include a subjective assessment and changes in FVC and exercise performance. Changes in FEV1 appear to have less clinical relevance.

Airway Obstruction↗
PubMed1978

Dyspnoea, disability, and distance walked: comparison of estimates of exercise performance in respiratory disease.

Forty-four patients with airway obstruction and 18 with pulmonary infiltration were studied in an attempt to correlate exercise tolerance, as assessed by a simple walking test, with basic respiratory function values and differing subjective assessments of exercise performance. The distance walked in 12 minutes was significantly correlated with the response to a structured questionnaire and with the patients' assessment of performance using an oxygen-cost diagram. The distance walked did not agree well with simple subjective estimates obtained in the clinical history. It was better correlated with forced vital capacity than with forced expiratory volume in one second in both groups of patients, and was well correlated with carbon monoxide transfer factor in those with pulmonary infiltration. The scatter of results, however, was such that exercise performance could not usefully be predicted from the respiratory function values or from subjective assessments. Simple exercise tests are an essential part of assessing disability and response to treatment in patients with respiratory impairment.

Adult↗
PubMed1978

The effects of oral propranolol and metoprolol on lung function and exercise performance in chronic airways obstruction.

Fifteen men with chronic airways obstruction received a test dose of propranol 20 mg orally. Six developed increased breathlessness. Nine who tolerated the test dose received metoprolol (100 mg) and propranolol (80 mg) on different days in a randomized double-blind fashion. Changes in resting and exercise heart rate, spirometry and exercise tolerance were measured 1 and 6 hours later. The drugs had similar effects on heart rate. Propranolol, but not metoprolol, caused significant reduction in forced expiratory volume in one second (FEV1) and peak expiratory flow rate. Neither drug produced significant changes in forced vital capacity (FVC) or exercise performances in the group as a whole, although the range of changes was wide. Despite considerable reduction in FEV1 and FVC in some individuals, most reported no increase in symptoms. Changes in exercise tolerance at 1 hour correlated significantly with changes in FVC but not with those in FEV1. It is proposed that changes in FEV1, though of pharmacological interest, may be less relevant clinically than changes in FVC.

Administration, Oral↗
PubMed1977

Cellulitis in complicated pneumococcal pneumonia.

Serious complications of pneumococcal pneumonia have become uncommon. This has been attributed to decline in pneumococcal infection (van Roy et al. 1971; Foy et al. 1975), but in this country it is more likely to be due to effective antibiotic therapy. We report a case of pneumococcal pneumonia with severe complications (including a very unusual one) which probably arose through antibiotic failure.

Aged↗
PubMed1977

Physical rehabilitation for the chronic bronchitic: results of a controlled trial of exercises in the home.

Twenty-four men with chronic bronchitis participated in a controlled trial of a physical training scheme. The training involved progressive stair-climbing exercises carried out over a three-month period unsupervised at home. The twelve men in the exercise group benefited significantly in terms of general well-being and reduced breathlessness. Their exercise tolerance increased significantly as judged by increased walking speed in a simple 12-minute walking test and by a greater work load tolerated in a progressive work load test on a bicycle ergometer. The mean stride length during the walking test increased significantly with training. No significant changes occurred in body weight, ventilatory function tests or heart rate on exercise. There were no important changes in the control group. It is not clear whether the improvements noted were due to physiological changes such as improved neuromuscular coordination producing a more efficient walking pattern or to predominantly psychological factors such as increased tolerance of dyspnoea. The study demonstrates that a simple training scheme which can be administered from a hospital clinic or family doctor's surgery is safe, feasible, and of benefit to the chronic bronchitic.

Aged↗
PubMed1976

Twelve-minute walking test for assessing disability in chronic bronchitis.

The distance covered in 12 minutes' walking was used to test exercise tolerance in chronic bronchitis. The distance covered bore a poor relation to the forced expiratory volume in 1 second but a significant relation to the forced vital capacity and the maximum oxygen consumption and ventilation on a bicycle ergometer. The test may be a simple practical guide to everyday disability in chronic bronchitis.

Adult↗
PubMed1976

Immunoglobulins and complement in pleural effusions associated with bronchogenic carcinoma.

Levels of IgG, IgA, IgM, the total haemolytic complement (CH50), and the individual components C1q, C3, C4, C6, and C7 were measured in 29 pleural effusions. Of these, 18 were associated with carcinoma of the bronchus and 11 were non-malignant effusions including empyemas. The level of IgG was significantly lower in the malignant group when compared with non-malignant effusions. The usefulness of measurements of IgG with respect to malignant effusions associated with carcinoma of the bronchus requires an expanded study to show whether it has any real diagnostic value. There were no significant differences in other immunoglobulins, the CH50, and individual complement components between the two groups. The identification of total haemolytic activity in the majority of effusions in both groups indicates that all nine components of the classical pathway of complement, including macromolecules such as C1, can be present in pleural fluids.

Carcinoma, Bronchogenic↗