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Biomedical subjects

M McDermott

Publications and source records attributed to M McDermott.

At least 145 records · Page 8Linked to original sources
PubMed1982

Acute renal failure in McArdle's disease.

A 35-year-old man had acute renal failure and was subsequently diagnosed as having rhabdomyolysis secondary to McArdle's disease, a primary myopathy due to myophosphorylase deficiency. Although it is a recognized cause of intermittent myoglobinuria, it has, nevertheless, rarely been associated with acute renal failure. The most likely explanation is that patients with this myopathy, because of mild muscle symptoms early in life, recognize their exercise limitations and thus avoid severe myoglobinuric episodes. However, unusually vigorous anaerobic muscle activity may produce myoglobinuria sufficient to cause renal damage. When acute renal failure does occur, the clinical course is similar to that of patients with other types of myoglobinuric renal failure.

Acute Kidney Injury↗
PubMed1982

Lung function and radiographic change in chrysotile workers in Swaziland.

The effect on lung function and radiographic indices of exposure to chrysotile asbestos was investigated by cross-sectional studies in two groups of men at Havelock Mine, Swaziland. The first group consisted of 214 employees and ex-employees, mean age 52, who had been employed for at least 10 years, and whose dust exposure ranged from minimal for surface workers to very heavy for those in the grading and bagging sections of the mill. In this group 29% had category 1 or more simple pneumoconiosis and 4.5% category 2 or more. For surface and mine workers, the estimated annual deterioration in FEV1 and FVC and the increase in category of pneumoconiosis was similar to that due to age alone, while the heaviest exposure almost doubled the decline in lung function and trebled the rate of progression of pneumoconiosis. The second group consisted of 224 men, mean age 33, all currently working in the mill and having been employed there for at least a year. In this group 30% had category 1 or more simple pneumoconiosis, and 2.7% category 2. Exposure in the dustiest sections of the mill more than doubled the estimated annual decline in lung function and doubled the rate of progression of pneumoconiosis.

Adult↗
PubMed1980

Effects of exposure to slate dust in North Wales.

In a study of slate workers in four areas in North Wales 725 workers and ex-workers who had been exposed to slate and to no other dust were seen, together with 530 men from the same area who had never been exposed to any dust. Evidence of pneumoconiosis was found in one-third of the slate workers, and 10% had degrees of pneumoconiosis that would attract compensation (category 2 or higher). The prevalence of respiratory symptoms was high, and there was evidence of an effect of both simple and complicated pneumoconiosis on lung function additional to that of age. There was a high prevalence (40-50%) of radiological lesions suggestive of healed tuberculosis in men aged over 55. Either pneumoconiosis or old tubercular lesions (or both together) could account for the current symptomatology and disability of the men.

Adolescent↗
PubMed1979

Comparison of the new miniature Wright peak flow meter with the standard Wright peak flow meter.

Preproduction and current models of the miniature Wright peak flow meter have been compared with the standard Wright peak flow meter on normal and abnormal subjects. Early problems in production appear to have been overcome, and the current model agrees to within 3% with the standard peak flow meter, which is as close as the agreement between two standard instruments. The new mini-meter may be enclosed in a case, making direct comparisons with other instruments possible.

Humans↗
PubMed1978

Handicapped driver controls operability: a device for clinical evaluation of patients.

A simple device is described for measuring the force input capability of severely handicapped drivers to assist in prescribing motor vehicle adaptive controls to permit these patients to drive. The device uses off-the-shelf components and can easily be constructed in any small shop. Both steering wheel and hand control force inputs with either hand can be assessed. A recommended protocol, interpretation of findings and some clinical data collected at the Texas Institute for Rehabilitation and Research and Houston VA Hospital are also presented and discussed.

Automobile Driving↗
PubMed1976

Chrysotile-induced asbestosis: changes in the free cell population, pulmonary surfactant and whole lung tissue of rats.

Rats inhaling chrysotile asbestos contracted asbestosis and fibrosis of the lungs. Studies of biochemical and morphological changes (between normal and treated animals) show that chrysotile induces an increase in the lung free cell population and pulmonary surfactant levels. Lysosomal enzyme levels are elevated in both the whole lung and free cell population and there are considerable changes in macrophage morphology. It is suggested that the primary response of the lung to chrysotile is an increase in surfactant production coupled with an increase in free cell numbers, in order to prevent the cytotoxic effect of the dust.

Animals↗
PubMed1975

The surface properties of the lung in rats with alveolar lipo-proteinosis.

The physical behaviour of the intact lungs and of lung extracts from rats affected by alveolar lipo-proteinsosis as a consequence of silica inhalation, was studied by means of pressure volume relations and surface tension area loops. Air inflation of diseased lungs occurred at a lower pressure and collapse was less on deflation than in control specimens, although there appeared to be little change in elastic forces. When saline was used dusted rat lungs showed at higher lung volumes a peculiar hysteresis effect which is attributable to consolidation of alveoli by the lipid material. Extracts from affected lungs showed differences from controls in respect of maximum and minimum surface tensions and stability index but all the values fell within the accepted limits of normal. However, with extracts from pathological lungs the area of the hysteresis loop increased, the shape of the surface tension area curve was abnormal and the percentage compression required to reduce the surface tension to 120 muN/cm fell. Extracts from diseased lungs depressed the maximum surface tension of normal lung extracts and increased the hysteresis area but had little effect on the minimum tension, the stability index or the % compression to achieve 120 muN/cm. The response was thus mainly that of an extract from a dusted rat. The surface activity of phospholipids may be affected by neutral lipid, cholesterol and the products of cell breakdown, all of which occur in the alveolar material. The occurrence within the same lung of compunds which reduce surface tension and others which modify the same lung of compounds which reduce surface tension and others which modify this property suggests that their relative concentrations may determine the overall effectiveness of the lung lining.

Animals↗
PubMed1975

The effects of inhaled silica and chrysotile on the elastic properties of rat lungs; physiological, physical and biochemical studies of lung surfactant.

When rats breathed air containing approximately 70 mg m-3 of respirable crystalline silica 7 h daily for 10 days (2000 mg m-3 h) the surface tension forces of the alveolar lining film were reduced. This was shown both by surface tension measurements on lung extracts and by pressure-volume studies with air and saline filling of excised lungs. Larger quantities of inhaled silica produced similar effects. Chrysotile inhalation caused an even more marked decrease in the surface tension forces. In the chrysotile studies these findings were supported by biochemical estimations of the quantity of surfactant in the lungs, which was increased 10-fold by an inhalation of 6500 mg m-3 h. Electron microscopy showed an increased number of the type II alveolar cells which produce surfactant and of free phospholipid lattices in the air spaces of the lungs of rats exposed to chrysotile and silica. Both the surface tension and biochemical estimations on a control group of rats suggest that there is an increase in the amount of surfactant in the lungs up to about 12 months of age.

Animals↗