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Biomedical subjects

J E Cotes

Publications and source records attributed to J E Cotes.

At least 19 recordsLinked to original sources
PubMed1992

Standardization of single-breath transfer factor (TLCO); derivation of breathholding time.

Breathholding time is usually defined using the procedure of Ogilvie et al. or of Jones and Meade; these procedures depend on knowing when inspiration begins and, for the latter, when it ends. Some alternative procedures do not require this information. With a view to standardizing the measurement, transfer factor of the lungs for carbon monoxide (TLCO) was measured in 18 adults with labile airflow obstruction, who were assessed before and after inhalation of salbutamol. The inflection points defining the start and end of inspiration were defined visually (method 1), and by extrapolation of the linear part of the inspiratory limb of the single-breath trace (method 2). The spirograms met recognized standards of quality and were rated by experienced observers. Compared with method 1 the TLCO and related indices by method 2 were lower using the procedure of Jones and Meade and higher using the procedure of Ogilvie et al. in each case by, on average, 1.0%. The within- and between-day variabilities were independent of the method used. Thus, the extrapolation and visual methods yielded interchangeable results when applied by experienced operators. However, extrapolation may be easier for inexperienced operators.

Albuterol↗
PubMed1991

Is respiratory function diminished?

An association between diminished respiratory function and an environmental agent should reflect the magnitude of the exposure and not be due to technical error, bias, confounding factors, or chance. Bias is difficult to avoid; the best course is to make comparisons within a population of exposed individuals, not between them and a control group; the population should be defined and a high response rate achieved. The principal confounding factors are age, smoking, and other environmental exposures; their effects should be fully estimated for the population in question as otherwise they will be wrongly attributed to the environmental agent. Finally, the results should be scrutinized and, if possible, a second independent study should be planned.

Cross-Sectional Studies↗
PubMed1990

Longitudinal respiratory survey of shipyard workers: effects of trade and atopic status.

A respiratory sample survey of 609 shipyard workers was conducted in 1979: the men were reassessed an average of 7.2 years later. The 53 deaths between the surveys were related to age, level of lung function and smoking but not to trade as a welder or caulker/burner. Of the survivors, 488 (88%) were seen, including 425 men who had retired or been made redundant. Redundancy was related to age, smoking, and respiratory symptoms; the average reduction in duration of employment per symptom was 0.44 years. Changes in respiratory symptoms included onset of chronic bronchitis and wheeze on most days (numbers respectively 77 and 109) and increased breathlessness on exertion (n = 89); significant related factors included smoking, previous metal fume fever or pneumonia, and, for breathlessness, trade as a welder or caulker/burner. Electrocardiographic evidence for myocardial ischaemia was also associated with increased breathlessness. The annual declines in FEV1 and other spirometric indices were related to age, to being a smoker at the time of the initial survey, and to trade as a welder or caulker/burner compared with trades that did not involve welding or burning. There was significant interaction between these effects. In a subsample of 124 redundant workers there was also significant interaction between the effects of fumes and atopy (skin test positive to common antigens) or a raised serum IgE concentration. It was concluded that welding fumes interacted with smoking and an atopic constitution to cause respiratory impairment. The results related mainly to exposures in the past and were not necessarily relevant for present day conditions in the industry.

Age Factors↗
PubMed1990

Rating respiratory disability: a report on behalf of a working group of the European Society for Clinical Respiratory Physiology.

A rating procedure for respiratory disability has been developed; it entails measuring the symptom-limited maximal oxygen uptake or estimating the maximal uptake from the results of a submaximal exercise test and other relevant variables. The derivation assumes a linear scale of disability between the limits 0% and 100% which are defined. The percentage disability of 157 men with respiratory limitation of exercise has been used to delineate empirical grades of disability. These are of similar form to those used for grading respiratory impairment. More information is needed with a view to validation.

Disability Evaluation↗
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↗
PubMed1978

Variations in the lung size of children in Papua New Guinea: genetic and environmental factors.

In Papua New Guinea, rural village children of both sexes living in the highlands (1500--2000 m) were found to have mean values of forced vital capacity 27 per cent greater than children at sea level. Urban children with an apparently lower level of habitual activity had a lung size similar to that of rural children living at the same altitude. In a number of healthy children of coastal parents reared in the highlands and of highland parents reared on the coast, the size of the lung was, in general, appropriate for the altitude rather than for the parentage. These findings suggest that the highland--coastal difference is probably environmental rather than genetic in origin.

Adolescent↗
PubMed1978

Cardiac output during submaximal exercise in New Guineans: the relation with body size and habitat.

Cardiac performance in moderate bicycle exercise has been measured in five groups of New Guineans (N = 161). Men and women in both coastal and highland (2000 m) locations were studied, as well as a group of highland men after migration to the coast. The results have all been standardized to an oxygen consumption of 1 1.min(-1). Cardiac output values are similar to those previously quoted for Europeans; a significant positive correlation with body size is found, and resident highlanders appear to have slightly larger cardiac outputs (+4%) and larger stroke volumes (+10%) after adjustment for body size, but this is not because they have larger hearts. The highland migrants at sea-level share none of the 'altitude' characteristics of the highland residents and, after size-adjustment, correspond with the lowlanders. The cardiac frequencies of the lowland women are higher than the other groups (+15 beats.min(-1)) after adjustment for differences in body size. Their values are close to those found previously for moderately active Europeans, while all the other New Guinean subjects have lower cardiac frequencies probably because of their greater habitual activity.

Adaptation, Physiological↗
PubMed1977

Ventilatory capacity if healthy Chinese children: relation to habitual activity.

Ventilatory capacity, including forced expiratory volume (FEV 1-0) and forced vital capacity (FVC), and selected anthropometric indices have been obtained for 36 boys and 19 girls aged 5-10 years from a working class district in Kowloon. The ventilatory capacity is related to stature and is 13 per cent larger for boys than girls. After allowing for stature and sex the residual variation is significantly reduced by also allowing for the children's habitual activity. The ventilatory capacity of the more active children, including those who have lived all their lives in squatter huts on the hillsides, is on average 8 per cent larger than for the inactive children including those who have lived all their lives in tenement flats with lifts. The groups are apparently similar with respect to income, dietary pattern, intelligence and disease incidence, so that findings provide independent support for the hypothesis that the level of habitual activity during childhood contributes to the ventilatory capacity. The absolute level of ventilatory capacity resembles that of Nepalese children and differs from that of some other groups.

Activities of Daily Living↗
PubMed1977

Ventilation, cardiac frequency and pattern of breathing during exercise in men exposed to O-chlorobenzylidene malononitrile (CS) and ammonia gas in low concentrations.

Ventilation minute volume, tidal volume and cardiac frequency during submaximal exercise have been measured in healthy young soldier volunteers exposed to O-chlorobenzylidene malononitrile (CS) and ammonia gas in concentrations respectively of 0.16 to 4.4 mg.m(-3) and 50 to 344 mg.m(-3). The response of ventilation minute volume to the two gases is apparently similar; both gases cause a reduction of, on average 6%. With low doses this reflects a diminution in respiratory frequency whereas with higher doses it is due to a reduction in tidal volume which is accompanied by tachypnoea. The findings may result from stimulation successively of receptors in the larynx and of irritant receptors in the large airways of the lung. The pain which is a feature of exposure to CS but not to ammonia is due to stimulation of other so far unidentified receptors. Neither gas has a direct effect upon the exercise cardiac frequency.

Adolescent↗
PubMed1977

Clinical improvement of patients with emphysema after radiotherapy.

In advanced emphysema the reduced lung retractive force permits dynamic compression of the airways during expiration; this gives rise to breathlessness which is often refractory to conventional remedies. Radiotherapy causes shrinkage of lung tissue and has therefore been given as treatment to 10 patients with emphysema. They have been followed for two years, during which time three have died from various causes, but no adverse effect of radiotherapy has been observed. All the patients at some time experienced a reduction in breathlessness on exertion and an increase in the range of their daily activities; the distensibility of their lungs was on average reduced but the response to test exercise was not altered. The possibility that the clinical improvement may have been a placebo effect is now being investigated.

Aged↗