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Biomedical subjects

G M Cochrane

Publications and source records attributed to G M Cochrane.

At least 109 records · Page 6Linked to original sources
PubMed1980

Chronic stable asthma and the normal arterial pressure of carbon dioxide in hypoxia.

Arterial blood-gas tensions, pH, and peak expiratory flow rate were measured in 29 patients with chronic asthma in a stable state. The hypoxia in these patients was found to be comparable with the hypoxia seen in normal subjects at high altitude in its effects on arterial pressure of carbon dioxide (PaCO2). These results suggest that in patients with asthma the PaCO2 taken as normal should be related to the arterial oxygen tension. Any increase in the observed value compared with this predicted value indicates impaired respiratory control. This may well help in assessing the patients at greatest risk during an attack of asthma.

Adult↗
PubMed1980

Respiratory oscillations in arterial carbon dioxide tension as a control signal in exercise.

We have monitored oscillations in arterial pH (of respiratory frequency) in normal man at rest and during exercise. The pH oscillations are known to reflect respiratory oscillations in arterial carbon dioxide tension generated at the lungs. We have found that the pH oscillations increase in their upslope and downslope during exercise. This means that oscillations in arterial carbon dioxide tension can be considered as a control signal.

Carbon Dioxide↗
PubMed1980

Serum theophylline concentrations during multiple dosing with two sustained release methylxanthine preparations in normal subjects.

In normal subjects, receiving multiple dosing regimens with Slophyllin and Phyllocontin in does calculated to give either 4 mg/kg or 6mg/kg theophylline free acid twice daily, serum theophylline concentrations were frequently less than 8 mg/l. Accumulation of the serum theophylline trough concentration occurred during the first 3 days of multiple dosing, and was followed by subsequent stabilization or even decline in serum theophylline trough concentrations. Side effects were noted with both Slophyllin and Phyllocontin, but only on the higher dosage regimens; they occurred within 24--48 hr of starting the drug, and tended to diminish if dosing was continued. The accumulation effect of serum theophylline concentrations may explain the timing of adverse effects, and should be avoided by starting methylxanthine therapy at a low dose. This may be increased after a few days. Further dosage adjustment may be necessary in some patients and should be facilitated by measurement of serum theophylline trough concentrations.

Adult↗
PubMed1980

Bronchial disease in ulcerative colitis.

Ten patients with ulcerative colitis, all of whom were non-smokers, presented with a productive cough. In six, the chest radiography was normal and cough was the only symptom; three of these patients had a minor obstructive ventilatory defect on testing. Four patients complained of exertional dyspnoea and had both an abnormal chest radiograph with bilateral pulmonary shadows and a mixed obstructive and restrictive ventilatory defect. Bronchial epithelial biopsies from four patients (two with and two without pulmonary shadows) revealed basal reserve cell hyperplasia, basement membrane thickening, and submucosal inflammation, changes more usually associated with cigarette smoking. Inhaled beclomethasone diproprionate relieved cough in seven patients. The occurrence of airway epithelial disease in association with ulcerative colitis raises the possibility of a systemic mechanism affecting both bronchial and colonic epithelium. It does not seem likely that sulphasalazine was the cause of the pulmonary syndrome in these subjects.

Adult↗
PubMed1980

Maximal expiratory flow volume curves in workers exposed to asbestos.

We have studied 40 workers with varying industrial exposure to asbestos, using routine spirometry and maximal expiratory flow volume curves (MEFVC). Abnormalities of MEFVC were common and seen in those with normal spirometry and total lung capacity. The high incidence of abnormal MEFVC suggests that air flow dysfunction in small airways may follow prolonged asbestos exposure. Our findings support, therefore, the idea that asbestos exposure may cause an obstruction to airflow arising particularly in small airways, and that one of the common functional abnormalities attributable to asbestos exposure is airways obstruction.

Adult↗
PubMed1979

Bronchodilators.

Explore the source record for details and available documents.

Adrenal Cortex Hormones↗
PubMed1978

Glucose, glycine and diglycine in test meals at stimuli to a duodenal osmoreceptor slowing gastric emptying.

1. Five subjects took 210 test meals of 750 ml. water containing 30--300 m-molal glucose or glycine, or 15--150 m-molal diglycine, or plain water. 2. The greater the concentration of solute, the greater was the volume of original meal recovered from the stomach after a fixed time. 3. On a molal basis glucose was half as effective as diglycine in slowing gastric emptying. This was consistent with the osmoreceptor being exposed to the diglycine after it had been split by the hydrolase of the cytosol of enterocytes (the absorbing cells of the small intestine). 4. The slowing of gastric emptying (ml./mole.1.) was about 10% greater for glycine than it was for glucose. There was apparently a threshold concentration below which glycine did not slow gastric emptying. 5. It was proposed that the response of the doudenal osmoreceptor might depend upon shrinking and swelling of the lateral intercellular space around the enterocytes.

Chemoreceptor Cells↗
PubMed1978

Spirometry in healthy men: a correlation with smoking and with mild symptoms.

Symptoms, smoking history, and variates taken from the forced expiratory manoeuvre were studied in a group of 271 healthy men attending a mass radiography unit. It was found that correlation of the forced expiratory ratio (FEV1/FVC) with the presence of mild or moderate respiratory symptoms was at least as satisfactory as that of technically more complicated measurements such as MEF50 and MEF75. In asymptomatic individuals those differences associated with smoking were the same for FEV1/FVC as for MEF75. Asymptomatic abnormalities of lung function were not observed. Simple measurements such as FEV1/FVC can therefore provide as much information from a forced expiratory manoeuvre to screen for early airways obstruction as MEF50 and MEF75.

Adolescent↗
PubMed1977

Effects of sputum on pulmonary function.

The specific airways conductance (SGAW) of 23 patients with copious sputum production and airflow obstruction was measured before and after physiotherapy to determine the effect of bronchial secretions on pulmonary function. Chest physiotherapy to remove these secretions had the effect of reducing airflow obstruction, as measured by SGAW. These findings suggest that sputum has a detrimental effect on pulmonary function and that physiotherapy can reduce airways obstruction.

Adolescent↗
PubMed1977

Intrasubject variability of maximal expiratory flow volume curve.

Analysis of airflow in the terminal portion of the maximal expiratory flow volume curve has been suggested as a useful test for the early diagnosis of chronic airways obstruction. Whether such an analysis can identify early disease, and whether any subsequent action can prevent the progress of chronic airways obstruction, is unknown and will require prospective studies. As a precursor of such a study we have tried to establish the intrasubject variability of those tests of forced expiration which may be used for screening. We therefore measured expiratory flow volume curves of five healthy males and five healthy females aged 20-30 years as this is an age-group in which early detection of airways obstruction may be of value. Flow volume curves were obtained on the same day of the week for six weeks, and on three separate days during this period we carried out three flow volume curves every hour from 9 am to 6 pm. The data were subjected to analysis of variance to determine the variability of each measurement. Data were collected from forced expired volume in one second (FEV1) forced vital capacity (FVC), maximum expiratory flow rates at 50% and 75% of expired vital capacity, and forced expiratory time (FET). The results showed no consistent pattern of diurnal variation over the working day. The variation in any subject for FEV1 and FVC over the study period was considerably less than variations detected in the maximal expiratory flow rates at 50% and 75% of the expired vital capacity and FET. Our results suggest that the intrasubject variation found in flow rates of the terminal portion of the maximal expiratory flow volume curve and forced expiratory time may limit the usefulness of these tests in detecting early airways obstruction. FEV1 and FVC are more reproducible tests and are therefore particularly suited for cross-sectional screening. The more sensitive maximal expiratory flow volume curve may, however, be more useful for long-term studies in individuals when the onset of disease is sought, or for short-term challenge studies requiring the most sensitive index of change in airway characteristics.

Adult↗
PubMed1976

Exercise-induced bronchocontriction, skin sensitivity, and serum IgE in children with eczema.

Forty-two children with eczema were studied for exercise-induced asthma (EIA), skin sensitivity to prick testing, blood eosinophil count, and immunoglobulins. 29 had a fall in peak expiratory flow rate after exercise greater than 20% and of these, 23 had symptoms of wheezing. 13 of the eczematous children showed a fall of less than 20%. The children with EIA showed greater cutaneous sensitivity (p less than 0.001) and a higher total serum IgE (p less than 0.025). 3 of the group with a fall of less than 20% had allergic rhinitis with skin sensitivity to grass pollen. The remaining 10 had no clinical evidence of allergic disease, other than eczema and skin sensitivity, and total IgE fell within the normal range. It is suggested that in a proportion of chilren with eczema there is little evidence of reaginic allergy.

Adolescent↗
PubMed1975

A double-blind comparison of naproxen with indomethacin in osteoarthrosis.

Twenty-two patients with osteoarthrosis of one or both knee joints and 28 patients with osteoarthrosis of one or both hips completed a double-blind trial of 500 mg naproxen daily versus 100 mg indomethacin daily. All patients had been on other active medication up to the start of the trial. Identical trial designs were followed with both classes of patients, namely, a crossover pattern of four weeks on each drug with patients being assessed at -2, 0, 2, 4, 6, and 8 weeks. Assessments made included objective measurement of joint range, stair climbing and walking times, and subjective grading of pain present during normal activity, of which the patient kept a daily record. Patients were also questioned at each clinic visit regarding possible side effects. Study groups were comparable for both drugs. In the majority of subjective and objective parameters, there were significant improvements from baseline on both drugs of statistically comparable magnitude. Significantly fewer side effects were noted during the period on naproxen compared with those on indomethacin. There were no abnormalities discovered in hematologic or biochemical tests performed during the course of the trial.

Anti-Inflammatory Agents↗
PubMed1975

A survey of asthma mortality in patients between ages 35 and 64 in the Greater London hospitals in 1971.

We have examined the death certificates from all patients aged 35-64 years who were recorded as dying from asthma in Greater London Council hospitals in 1971. Of the 47 death certificates studied, nine suggested that the primary cause of death was not asthma. From the remaining 38 deaths we have obtained 36 case records and found that 15 deaths occurred outside hospital and another two patients died in hospital having been admitted in a stable state. We have examined the remaining 19 case records to find out the circumstances of death in patients with asthma who die in hospital. We have been unable to exclude the possibility that many of the deaths in hospital were avoidable. Assessment of severity in most patients was incomplete, as judged by a retrospective analysis of case records, and many of the patients would be regarded as having had insufficient treatment. Four patients did not receive corticosteroids and in a further three the dose given was small. No physiological assessment of airflow obstruction was made in over half the patients. A comparison with 19 survivors of an admission to hospital with asthma did not provide enough information to account for the deaths. The survivors were in hospital for a shorter period of time, were slightly less ill, and were given comparable treatment regimens. Both groups of patients were inadequately assessed, and sedatives were given to approximately 70% of all subjects studied. The deaths in hospital usually occurred suddenly in the early morning in general medical wards.

Adrenocorticotropic Hormone↗
PubMed1975

Clinical relevance of the flow rate response to low density gas breathing in asthmatics.

The maximal expiratory flow rate response to low density gas breathing was examined at the mid-vital capacity point in 31 asthmatic patients. Clinical features and long-term follow-up date were documented to assess the clinical relevance of the various responses. Many of the patients with chronic asthma had not responded adequately to outpatient therapy, and they had been admitted to hospital for evaluation and management. With increased steroid doses and intensive bronchodilator therapy, all showed considerable improvement and were studied when this improvement occurred. The remainder of the patients were studied after recovery from acute asthmatic attacks or during maintenance management as outpatients. All patients with a forced expiratory volume in 1 second is greater than 75 per cent of the predicted value and mid-expiratory flow rate is greated than 50 per cent of the predicted value at the time of study showed a good response to helium. Those patients with more severe obstruction could be divided into 2 groups, responders and nonresponders. A qualitatively similar response to normal subjects (density-dependent flow rates) was a feature of those patients who in general showed further improvement in ventilatory function on follow-up. A qualitatively similar response to that seen in patients with chronic irreversible obstruction (density-independent flow rates) was a feature of those patients who in general showed no further improvement in ventilatory function on long-term follow-up. There were, however, exceptions to both groups. We conclude that in asthmatics with more than mild air flow obstruction, the assessment of helium response can be of value in identifying those patients who have, in addition to asthma, chronic irreversible obstruction due to concommitant chronic bronchitis and/or emphysema. Clinical assessment and measurement of single-breath diffusion of carbon monoxide provide additional support for the latter diagnoses and separate the few exceptions from the bulk of the nonresponders. Responders and nonresponders can be fairly reliably identified from the simply recorded exhaled flow volume curve, thus obviating the need for a volume displacement plethysmograph.

Acute Disease↗