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Biomedical subjects

A Cockcroft

Publications and source records attributed to A Cockcroft.

At least 37 records · Page 2Linked to original sources
PubMed1990

Antibody response after hepatitis B immunisation in a group of health care workers.

Hepatitis B immunisation has been offered to staff of Hampstead Health Authority since 1982 and is now offered to all staff with clinical contact. Three doses of 20 micrograms of vaccine are given at zero, one, and six months and the antibody response is measured three months later. Results were analysed to seek for associations with the antibody response. At the time of analysis, 2739 people had started vaccination and 1067 had completed the course and had a measurement of antibody response. Vaccine injections were initially into the buttock and later into the arm; measurement of antibody levels was initially by radioimmunoassay (RIA) and later by enzyme immunoassay (EIA). A positive antibody response was defined as a positive/negative ratio of greater than 10 for RIA or a level of greater than 10 mIU/ml for EIA. Associations between antibody response and other variables were tested by chi 2 and a multiple logistic regression analysis was undertaken to examine the effects of variables in combination. The overall antibody response rate was 95%. Men and women did not respond differently but there were significantly more positive responses with the EIA testing method and a tendency for more positive responses with arm injections. The responders were significantly younger than the non-responders and had significantly lower values of body mass index (wt/ht2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

AIDS/HIV counselling in occupational health.

AIDS/HIV counselling will increasingly become part of the role of occupational health professionals. Issues that arise in the occupational setting include: occupational transmission, knowledge and attitudes, problems with family and friends, AIDS dementia, and uncertainty. Dilemmas can occur in relation to contamination incidents, HIV positive employees, or staff refusing to work because of fears of HIV/AIDS. It it easier to deal with the problems that arise if the issues have been thought through beforehand. Examples are given of problems that have occurred in a setting of occupational health in the British Health Service and their resolution is discussed.

Counseling↗
PubMed1989

AIDS/HIV infection and employment: the role of occupational health services.

Occupational health services need to be active in the development of local policies about AIDS/HIV and employment. Employment issues include the possible hazards from HIV infected employees, which are more fears than real risks, and the problems faced by HIV infected employees. Pre-employment HIV screening does not eliminate HIV from the workforce and involves much extra work. The occupational health service can be a source of confidential counselling for HIV infected individuals and will need to advise on work fitness. HIV as a bar to certain jobs is difficult to justify. The problems relating to HIV infection at work are best dealt with by education of staff at all levels.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Assessment of breathlessness.

In summary, breathlessness is an important symptom in a number of disease states. The most appropriate techniques for assessment of the symptom depend on the circumstances, ranging from the time-honoured clinical interview by a skilled observer, through questionnaires for epidemiological use, to direct scaling of the sensation by subjects under experimental conditions. The use of direct scaling techniques has enabled researching into mechanisms of breathlessness in recent years, resulting in an increased understanding of the sensation, but no significant therapeutic advances as yet. An area of current research interest is study of the different descriptors for the sensation used by different subjects. This may have great practical importance because it may be that, as with pain, different types of breathlessness will respond to different types of treatment.

Dyspnea↗
PubMed1988

Pulmonary rehabilitation.

Rehabilitation of patients with chronic respiratory disease has tended to be neglected in the past, partly because of a generally pessimistic view of their prospects. Simple programmes of exercise training can produce measurable increases in exercise tolerance and sometimes great improvements in quality of life for respiratory patients. The effects of exercise seem to be through improvement in exercise efficiency. A full rehabilitation programme also involves an attempt to deal with patients' psychological problems and to help them regain independence in all aspects of their lives. The opportunity exists to improve the lot of a large group of people, at a relatively modest cost.

Exercise Therapy↗
PubMed1987

Controlled trial of respiratory health worker visiting patients with chronic respiratory disability.

Seventy five patients with chronic respiratory disability were randomised to a group visited by a respiratory health worker (42) or control group (33). The first group was visited monthly by a respiratory nurse, who gave education and support. The effect of the intervention was assessed in terms of quality of life (by questionnaires), the number and duration of admissions to hospital, and the number of deaths. The questionnaires on quality of life showed no changes in either group during the study, but nearly all of the group visited by a respiratory health worker said that they valued the visits and wished them to continue. Their knowledge about their condition also improved compared with that of the controls. The duration of stay in hospital for respiratory reasons in the group visited by a respiratory health worker was longer than that of control patients. This was explained by their being scored as more ill than the controls on admission. Fewer patients died in the group visited by a respiratory health worker than in the control group (p = 0.11). The patients in the group visited by respiratory health workers may have survived longer because they sought help rather than dying at home. If confirmed this could have implications for the cost of their care.

Aged↗
PubMed1987

Arterial oxygen saturation and breathlessness in patients with chronic obstructive airways disease.

Nine patients with chronic obstructive airways disease performed a 6 min self-paced walk (breathing air) on a treadmill and then identical (but operator-controlled) treadmill walks breathing either air or supplemental oxygen sufficient to just prevent arterial oxygen desaturation during the exercise. During the exercises, ventilation was recorded and patients recorded their sensation of breathlessness on a visual analogue scale (VAS) every 30 s. Breathing supplemental oxygen produced a small fall in mean exercise ventilation and a large and consistent reduction in mean exercise breathlessness. In seven patients the VAS scores were higher on air than with supplemental oxygen, at similar levels of ventilation. An analysis of covariance, to control for reduction in ventilation, showed a decrease in mean breathlessness when breathing supplemental oxygen, significant at the 8% level. The reduction in breathlessness produced by preventing exercise desaturation cannot be explained by the decrease in ventilation. This suggests that hypoxia may be a stimulus for breathlessness. The mechanism is unknown.

Aged↗
PubMed1987

Voluntary isocapnic hyperventilation and breathlessness during exercise in normal subjects.

1. Nine normal subjects performed 6 min, constant-workload, exercise tests on a bicycle ergometer at either a 'high workload' or at a 'low workload'. During the first 'high workload' test their spontaneous breathing pattern was recorded on to magnetic tape. During one subsequent 'high workload' test and one 'low workload' test they voluntarily copied their recorded breathing pattern. During a second 'low workload' test they breathed spontaneously. Isocapnia was maintained by the operator throughout both the copying tests. During the exercise tests ventilation was recorded and subjects indicated the level of their sensation of breathlessness every 30 s. 2. Subjects felt markedly less breathless when a proportion of their ventilation was produced by voluntary effort than when the same total level of ventilation was produced entirely by the stimulus of exercise. Furthermore, voluntary isocapnic hyperventilation during exercise did not increase breathlessness above that normally associated with that level of exercise. 3. These results suggest that it is reflexly driven ventilation, and not simply the level of ventilation itself, which relates to the level of breathlessness during exercise.

Adult↗
PubMed1987

Radiological irregular opacities and coalwork exposure: a case-referent study.

Five hundred and fifteen men newly attending chest clinics in coalmining areas of England and Wales were entered into a study of the risk of irregular opacities on the chest radiograph in relation to occupation; readable radiographs were received for 489. The men completed questionnaires on occupational and smoking history and the radiographs were read for irregular opacities by the collaborating chest physicians and by a panel of three readers using the ILO 1980 classification. Older men had more irregular opacities than younger men, but coalworkers had a significant excess risk of nearly three times of having irregular opacities, which remained after stratifying for smoking and age. Lung cancer was evident on 14% of the radiographs and was significantly less common in coalworkers than non-coalworkers. The findings are consistent with a causal association between coalwork exposure and irregular opacities. Other evidence suggests that these opacities are associated with emphysema in coalworkers.

Adult↗
PubMed1987

Breathlessness.

Explore the source record for details and available documents.

Humans↗
PubMed1986

Central lymph node changes and progressive massive fibrosis in coalworkers.

Lungs from 123 coalworkers coming to necropsy were examined to determine the association between dust related changes in the central lymph nodes and progressive massive fibrosis and secondary foci in the lung parenchyma. Increasingly extensive changes of the central nodes were scored macroscopically, the highest scores indicating erosion through the walls of adjacent bronchi or branches of the pulmonary artery or both. In 88 cases (mainly with extensive changes) microscopic assessment was also made. Increasingly extensive changes of central nodes were associated with the presence of progressive massive fibrosis in the lungs (p less than 0.001) and the presence of secondary foci in lungs without progressive massive fibrosis (p less than 0.03). Microscopic assessments agreed fairly well with macroscopic assessments, but tended to be assigned lower scores. A hypothesis for the pathogenesis of progressive massive fibrosis is proposed whereby dust, accumulating in central lymph nodes, leads eventually to spread through the capsule and rupture into bronchi or pulmonary vessels, thereby sending dust laden activated cells back into the lungs to produce progressive massive fibrosis. These preliminary results are consistent with the hypothesis but more detailed studies are required.

Coal Mining↗
PubMed1985

Arterial oxygen desaturation during treadmill and bicycle exercise in patients with chronic obstructive airways disease.

Nine men with severe chronic obstructive airways disease (COAD), known to desaturate on exercise, performed a 6 min self-paced walk on a treadmill, followed by a bicycle exercise with workloads adjusted to mimic the oxygen consumption achieved on the treadmill. During both exercises, ventilation, oxygen consumption, carbon dioxide production, PaO2, PaCO2, pH and arterial lactate were measured and subjective breathlessness recorded. A reasonable match of oxygen consumption between the two exercises was achieved. In all subjects PaO2 fell to a lower level during treadmill compared with bicycle exercise. Ventilation, carbon dioxide production and arterial lactate were higher during bicycle exercise. Subjective breathlessness was greater during bicycle exercise, in proportion to the higher ventilation on the bicycle. The greater anaerobiosis occurring on the bicycle led to acidosis and an increased ventilation, minimizing the exercise fall in PaO2. Bicycle testing may seriously underestimate exercise desaturation occurring during level walking in patients with severe COAD.

Aged↗
PubMed1985

Breathlessness during different forms of ventilatory stimulation: a study of mechanisms in normal subjects and respiratory patients.

This study investigates the mechanisms underlying the perception of breathlessness induced by hypoxia and hypercapnia in both naive normal subjects and patients with respiratory mechanical problems. In normal subjects separately receiving both oscillating hypercapnic and hypoxic ventilatory stimulation, equivalent peak stimulus intensities in end-tidal gas were associated with a 'damped' ventilatory response when the frequency of stimulation was increased. A concomitant fall in peak breathlessness levels on a visual analogue scale was recorded in each case. In normal subjects and patients, the voluntary copying of a ventilatory pattern recorded during oscillating hypercapnic stimulation was associated with a marked diminution or complete absence of breathlessness despite equivalent levels of peak ventilations achieved. Voluntary copying of hypercapnic stimulated ventilation was not associated with any demonstrable change in the distribution of muscle movements between the chest wall and abdomen. These results suggest that the intensity of breathlessness depends on the level of effective reflex stimulation of the respiratory-related neurones in the medulla. They cannot be explained solely in terms of perception of afferent neural information arising from either chemoreceptors or respiratory mechanoreceptors.

Abdomen↗
PubMed1985

A self paced treadmill walking test for breathless patients.

A treadmill exercise test is described that retains the advantages of self paced walking but allows the measurement of cardiorespiratory variables. A horizontal treadmill was modified to allow patients to control their own speed. During exercise continuous measurements of speed, distance, heart rate, arterial oxygen saturation, and stride length were made and subjective assessments of breathlessness were recorded on a visual analogue scale. Ten men with severe chronic obstructive lung disease performed a 12 minute corridor walk and a self paced 12 minute treadmill walk on the same day and repeat treadmill walks on different days. Six of them performed three walks or more. Six patients had ventilatory measurements during treadmill exercise. There was no significant difference (p greater than 0.1) in the distance covered during corridor and treadmill walks, and distances on the treadmill were repeatable after the first walk. Use of a mouthpiece significantly reduced the distance covered on the treadmill. The self paced treadmill walk is a simple repeatable test and has advantages over both a corridor walking test and standard progressive tests for assessment of breathless patients.

Aged↗
PubMed1984

Recycling of transferrin receptors in A431 cells is inhibited during mitosis.

There is a marked reduction in the number of surface transferrin receptors as A431 cells enter mitosis which persists until telophase when receptors reappear to a level that exceeds the original interphase value. This is most simply explained by assuming that recycling of receptors back to the cell surface is inhibited as cells enter mitosis but that internalisation continues for a short while, causing surface receptor depletion. In telophase recycling would resume before internalisation giving a temporary excess of surface transferrin receptors.

Carcinoma, Squamous Cell↗
PubMed1983

Prevalence and relation to underground exposure of radiological irregular opacities in South Wales coal workers with pneumoconiosis.

A total of 124 coal workers and ex-coal workers receiving disability benefit for coal worker's pneumoconiosis and routinely reattending the Cardiff Pneumoconiosis Medical Panel during a 10-week period were studied. Those with complicated pneumoconiosis were excluded. Their current chest radiographs and their chest radiographs at the time of certification were read in random order by three readers using the 1980 ILO Classification of Radiographs. An irregularity score was derived from the readings. The x-ray findings were examined for changes since certification and for relationships with age, smoking, and underground coal work exposure. One-fifth of the current radiographs showed mainly irregular opacities, whereas nearly all of those from the time of certification showed mainly irregular opacities, whereas nearly all of those from the time of certification showed mainly rounded opacities. Irregular opacities were related to age, smoking, and underground exposure. The exposure effect remained after excluding the older men. The findings suggest that radiological irregular opacities, and their associated pathology and lung function changes, commonly develop in coal workers with pneumoconiosis and should be considered part of the condition.

Adult↗
PubMed1982

Post-mortem study of emphysema in coalworkers and non-coalworkers.

A post-mortem survey of emphysema in coalworkers and non-coalworkers was carried out in men aged 50-70 years dying of ischaemic heart disease (IHD). It was determined that in such men selection for necropsy was similar in coalworkers and non-coalworkers. All lungs were examined in a standard way and the amounts of centrilobular and panacinar emphysema were scored on numerical scales. Emphysema in men dying of IHD was significantly more frequent in coalworkers than in non-coalworkers even after age and smoking habits were accounted for by stratification. In the coalworkers, the severity of emphysema was related to the amount of dust in simple foci in the lungs. Because both groups were selected similarly from their parent populations the relative frequency of emphysema found in this study reflects that in the whole populations of coalworkers and non-coalworkers in the study area and confirms an excess of emphysema in coalworkers. This excess is likely to be due to occupational factors.

Aged↗