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Biomedical subjects

J E Cotes

Publications and source records attributed to J E Cotes.

At least 73 records · Page 4Linked to original sources
PubMed1984

Lung transfer factor and KCO at cardiac frequency 100 beats/min as a guide to impaired function of lung parenchyma.

Transfer factor (TL) and KCO have been measured by the single breath carbon monoxide method in 39 patients with confirmed or suspected lung disease, mostly of occupational origin, and 37 healthy subjects. TL and KCO at an exercise cardiac frequency of 100 beats/min (TL100 and KCO100) and the slopes of the regression of exercise transfer factor and KCO on exercise cardiac frequency (delta TL/delta fC and delta KCO/delta fC) were obtained. The discriminatory performance of these indices in detecting defective gas transfer was compared with that of TL and KCO at rest (TLrest and KCOrest). The slope indices did not distinguish between healthy subjects and patients with emphysema or conditions of the lung parenchyma, including asbestosis. The slope indices also failed to distinguish between individuals with normal and abnormal gas transfer at rest. The indices TL100 and KCO100 contributed additional information not contained in the indices at rest and they merit further study.

Adult↗
PubMed1984

Relationship of ventilatory capacity to hyperbaric exposure in divers.

The results of divers' annual medical examinations were used to assess the effects of diving exposure independent of age, stature, and smoking on forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). Cross-sectional analysis of records for 858 men showed a significant positive association between the maximal depth that subjects had experienced and FVC but not FEV1. There was a significant negative association for FEV1/FVC%, and this index was also positively correlated with years of diving exposure. Among a subsample of 81 men the forced expiratory flow rate at low lung volume was reduced relative to that of control subjects similarly assessed; the extent of the reduction from the reference value was significantly correlated with the diving exposure. Longitudinal analysis of results for 255 men over a minimum of 5 yr showed that the change in FVC per annum (positive or negative) was correlated with the change in maximal depth; there were no similar associations for FEV1 or FEV1/FVC%. Thus diving exposure affects the vital capacity and the forced expiratory flow rate at small lung volumes. The latter is evidence for narrowing of airways that might be secondary to diving-induced loss of lung elastic tissue; this hypothesis merits further investigation.

Adult↗
PubMed1982

Shape of small opacities and lung function in coalworkers.

Lung function and chest radiographs were reviewed in 357 coalworkers who had been referred from the Cardiff Pneumoconiosis Medical Panel. The chest films were read according to the 1980 ILO classification of radiographs by three experienced readers. An irregularity score, reflecting the shape of the small opacities, was derived from the readings and compared with the lung function variables. Men with higher irregularity scores had significant reductions in ventilatory capacity and gas transfer factor, with no change in total lung capacity, after age, height, profusion of small opacities, and smoking habit had been taken into account. The effects were present both in those with and in those without large opacities. The agreement between readers over the shape of opacities was almost as good as for their profusion. Men with rounded opacities had a lower gas transfer factor if they were predominantly of the "p" type. The results are consistent with those for a combination of emphysema and interstitial fibrosis, which has been found in coalworkers with irregular opacities.

Adult↗
PubMed1981

Absolute FEV1 values.

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Forced Expiratory Volume↗
PubMed1981

Lung function of office workers exposed to humidifier fever antigen.

Office workers who became sensitised to antigens derived from humidifier sludge developed episodes of fever, malaise, and other symptoms, including polyuria and mild chest tightness. The episodes usually occurred on a Monday evening and were to some extent dose-related. Lung function was assessed over a day shift on two occasions, including one after which almost all the susceptible subjects developed symptoms. The symptoms were preceded by a 6% reduction in forced expiratory volume and vital capacity, a corresponding increase in residual volume, and a reduction in flow rate after 75% vital capacity had been expired. There were no changes in peak expiratory flow, forced expiratory flow at 50% of vital capacity, or transfer factor. In some subjects the transfer factor was apparently reduced 36 hours later, but for this there may have been another explanation. The physiological features were considered to reflect narrowing of small airways in the lung. The changes, however, were minimal and not the main cause of the symptoms. A feature of the episode was the severity of the constitutional symptoms despite the low airborne dust levels.

Adult↗
PubMed1981

Relationship between type of simple coalworkers' pneumoconiosis and lung function. A nine-year follow-up study of subjects with small rounded opacities.

One hundred and twenty-five men who were identified in 1968 as having the simple pneumoconiosis of coalworkers were re-examined nine years later when their mean age was 59.6 years. On both occasions the lung function and response to exercise were assessed. There was no evidence for progression of simple pneumoconiosis between the surveys, but 14 had developed small irregular opacities on their chest radiographs and 28 showed early changes of progressive massive fibrosis (PMF). After allowing for the effects of smoking and of exposure to coal dust, subjects with both p and r types of simple pneumoconiosis exhibited a reduced transfer factor compared with subjects having q-type opacities; subjects with r-type opacities also showed an increased pulmonary elastic recoil pressure. The presence of irregular opacities, independent of rounded opacities, was associated with a low transfer factor and decreased slope of phase III of the single breath oxygen test. Subjects who developed PMF between 1968 and 1978 had p or r opacities more often than q opacities: these subjects had an increase pulmonary elastic recoil pressure. The development of PMF was also associated with physiological evidence of airways obstruction. The changes in subjects with r opacities are consistent with the presence of space occupying lesions that may progress to PMF. Subjects with p opacities have physiological evidence of emphysema as do some subjects with established PMF. Irregular opacities may reflect the presence of both emphysema and diffuse fibrosis. There is need for more morbid anatomical evidence on the underlying pathology.

Coal Mining↗
PubMed1980

Radiographic heart volume, stroke volume and exercise cardiac frequency: relationship to body composition and other factors in healthy adult males.

Amongst 288 healthy male workers in heavy industry the radiographic heart volume was related to the fat-free mass and the percentage body fat which between them explained 27% of the variance. Exercise was performed on a treadmill using a belt speed of 80 m.min-1 (3 mph) and an incline which was increased progressively to 14% when the oxygen uptake was on average 61% of the maximum for these subjects. The exercise cardiac output was related to the uptake of oxygen, the fat-free mass and the ambient temperature; these factors accounted for 52% of the variance. The exercise stroke volume was related to the heart volume, the fat-free mass, the thigh muscle width, the ambient temperature, the Harvard Pack Index and other measurements which between them accounted for 42% of the variance. The exercise cardiac frequency was correlated negatively with the heart volume, the fat-free mass, the age and the Harvard Pack Index. The variates between them described 41% of the variance. The findings provide reference values for heart volume, stroke and exercise cardiac frequency in similar subjects.

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

Lung function in healthy British women.

The forces expiratory volume, total lung capacity, transfer factor (diffusing capacity), and their subdivisions have been measured in 113 healthy British women aged 27 to 74 years of whom 47 were current smokers and 66 were lifetime non-smokers. The results have been analysed in terms of age, stature, mass, body fat, and smoking. In addition to their relation to stature and to age, the inspiratory capacity was positively correlated with indices of body muscle while the residual volume, expiratory reserve volume, and total lung capacity were inversely correlated with the percentage of body mass that is fat or with mass divided by the square of stature. The inverse correlation between total lung capacity and age was apparently due to the quantity of body fat increasing with age. The transfer factor and its subdivisions were inversely correlated with smoking. In this study the forced expiratory volume and vital capacity were independent of both fat and smoking; the transfer factor was independent of the physiological response to exercise. The results provide reference values for lung function in British women.

Adipose Tissue↗
PubMed1978

Ventilatory responses to exercise and to carbon dioxide in mitral stenosis before and after valvulotomy: causes of tachypnoea.

1. The ventilation and cardiac frequency during progressive exercise and the respiratory responses to breathing carbon dioxide have been measured in 33 female patients with mitral stenosis and in 31 control subjects. Compared with the control subjects, the patients' exercise ventilation and cardiac frequency were increased; the exercise tidal volume at standard minute volume, the vital capacity and the ventilatory response to carbon dioxide were reduced. The extent to which the standardized tidal volume was lower during exercise than during breathing carbon dioxide was correlated with the severity of the stenosis, as gauged by the increase in exercise cardiac frequency above the level predicted from anthropometric measurements. 2. Twenty patients were studied postoperatively. In the 12 who showed clinical improvement the exercise ventilation and cardiac frequency were reduced and the exercise tidal volume at a given minute ventilation was increased. The latter change occurred despite a reduction in vital capacity, which was probably a residual effect of thoractomy. There was no significant change in the response to breathing carbon dioxide. No material change in function was observed in the patients whose condition was not improved by the operation. 3. It is suggested that in mitral stenosis the tachypnoea which occurs during exercise, whilst mainly a mechanical consequence of the reduced vital capacity, is also partly due to pulmonary congestion stimulating intrapulmonary receptors.

Adult↗