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Biomedical subjects

D M Geddes

Publications and source records attributed to D M Geddes.

At least 217 records · Page 12Linked to original sources
PubMed1982

Computed tomography of the thorax in the diagnosis and management of malignant disease.

The role of computed tomography (CT) scanning in the investigation of patients with intrathoracic malignancy has not yet been clearly defined. Current evidence suggests that it is the most sensitive diagnostic imaging technique for identifying the extent of primary lung cancers and their relationship to intrathoracic anatomy. It is an advance in the staging of intrathoracic malignancy as it identifies adenopathy in the paratracheal region and the mediastinum more readily. Discovery of small (less than 0.8 mm) pulmonary nodules is common in patients with some extrathoracic malignant conditions, but differentiating malignant deposits from benign nodules remains a problem. CT has a potential place in radiotherapy field planning and in identifying lung cancers in the occasional patient presenting with suspicious symptoms or positive cytology and a normal chest radiograph.

Carcinoma, Small Cell↗
PubMed1981

Effects of dihydrocodeine, alcohol, and caffeine on breathlessness and exercise tolerance in patients with chronic obstructive lung disease and normal blood gases.

We measured breathlessness and exercise tolerance in 12 patients with chronic airways obstruction, moderate or severe breathlessness, and low or normal arterial carbon dioxide tension, after the patients received dihydrocodeine, alcohol, caffeine, or placebo (through double-blind administration). Forty-five minutes after ingestion, dihydrocodeine had reduced breathlessness by 20 per cent and increased exercise tolerance by 18 per cent, with a reduction in ventilation and oxygen consumption at submaximal work loads but with no change in spirometric volumes. Oxygen also reduced breathlessness and provided additional benefit to that achieved with dihydrocodeine (at three hours after ingestion) when the two were given together: the reduction of breathlessness was 18 per cent with dihydrocodeine; 22 per cent with oxygen; and 32 per cent with dihydrocodeine plus oxygen. Alcohol increased forced vital capacity by 9 per cent, and exercise tolerance by 7 per cent. Caffeine had no deleterious effect on breathlessness or exercise tolerance, despite increasing ventilation during rest and exercise. We conclude that opiates may be valuable for the treatment of breathlessness in selected patients; further evaluation is needed, particularly of the long-term benefits and safety.

Alcoholic Beverages↗
PubMed1981

Drug treatment of breathlessness: contrasting effects of diazepam and promethazine in pink puffers.

Fifteen out of 18 "pink and puffing" patients completed a double-blind, placebo-controlled cross-over trial of diazepam and promethazine for breathlessness and reduced exercise tolerance. Dosages were 25 mg and 125 mg daily, respectively, and each course lasted two weeks. Patients with psychiatric or other major medical histories were excluded. Of the three patients who did not complete the trial, one died during an exacerbation of breathlessness while taking diazepam, one was withdrawn because of mild hypercapnia while taking placebo, and one suffered intolerable drowsiness while taking diazepam. Of the remaining 15 patients, six needed a reduction in dosage because of drowsiness: one of these was taking promethazine and five diazepam. Diazepam had no effect on breathlessness and noticeably reduced exercise tolerance. Promethazine reduced breathlessness and improved exercise tolerance without altering lung function. From these results diazepam is contraindicated for breathlessness and reduced exercise tolerance in fixed airways obstruction, but promethazine may be beneficial.

Adult↗
PubMed1981

Oxygen relieves breathlessness in "pink puffers".

The effect of oxygen on breathlessness and exercise tolerance was examined in "pink and puffing" patients with fixed airways obstruction. When breathing oxygen, patients were less breathless and walked further. This was true whether the cylinder was carried by the patient or by an assistant. It was not possible to identify those patients who would benefit most. The best method of assessing improvement was by comparing breathlessness on a standardised progressive exercise test on a treadmill. Four patients had a greater than 30% reduction in breathlessness on submaximum exercise when breathing oxygen. Breathing oxygen for five or fifteen minutes before exercise but not during exercise (predose) resulted in a similar improvement in exercise tolerance. For short periods of exercise predosing with oxygen provides a convenient alternative to continuous oxygen. For longer periods of exercise the benefits of portable oxygen in selected patients have been previously underestimated.

Adult↗
PubMed1981

First-pass lung uptake of propranolol enhanced in anaesthetized dogs.

Uptake of 14C-propranolol after a single passage through the pulmonary circulation was studied in three groups of Labrador dogs using a double indicator dilution method. Uptake in conscious, ambulant animals was 53%. This increased to 81% in dogs anaesthetized with thiopentone, nitrous oxide and halothane and to 64% in dogs anaesthetized with thiopentone, nitrous oxide and fentanyl. Interaction between lipid-soluble anaesthetic agents and pulmonary endothelial cell membranes may be an important factor in increasing lung uptake of lipophilic propranolol, although alteration in pulmonary perfusion associated with a reduction in cardiac output during general anaesthesia may play a part. The pharmacological effects of propranolol administered i.v. during general anaesthesia may be unpredictable.

Anesthesia, General↗
PubMed1979

Airways obstruction in rheumatoid arthritis.

Owing to the report of an association between rheumatoid arthritis (RA) and obliterative bronchiolitis we have determined the prevalence of airflow obstruction in unselected patients with RA and normal chest radiographs. Spirometry was performed on 100 patients with rheumatoid arthritis and 84 control subjects matched for age, sex, and smoking habits. Patients with rheumatoid arthritis had significantly lower values for FEV1, FVC, FEV1/FVC, and MMEFR when compared with the controls: 39 patients had abnormal spirometry, and at least 32 showed airways obstruction. The prevalence of airflow obstruction is remarkably high, and we suggest that airway disease may be the commonest form of lung involvement in rheumatoid arthritis.

Adult↗
PubMed1979

First pass uptake of 14C-propranolol by the lung.

Uptake of 14C-propranolol by the lungs during a single passage through the pulmonary circulation was measured in ten patients at cardiac catheterisation. Mean lung uptake of propranolol was 75% in seven patients who were not previously taking the drug and 33% in three patients who were taking it as regular oral treatment. Lung uptake of propranolol in man is therefore considerable and is partly saturable by normal oral doses. This may alter the dose response relation for propranolol and a wide range of other drugs when given intravenously. The method used to study lung uptake is simple and might be suitable for studies of endothelial cell function in disease.

Administration, Oral↗
PubMed1979

Effects of pulmonary circulation on blood levels of insulin and glucagon in ambulant dogs.

The effect of the lung on insulin and glucagon were studied by comparing aortic and mixed venous levels in ambulant dogs with indwelling catheters. In the resting state ther was no difference for either hormone. After injection of insulin aortic levels exceeded mixed venous for 10 min; mixed venous levels exceeded aortic for the next 36 min. After injection of glucagon mixed venous levels consistently exceeded aortic. Single-pass studied showed an apparent gain in immunoreactive insulin as compared with [14C]inulin and 125I-albumin during passage through the lung; but no effect on glucagon could be demonstrated. A loss of immunoreactive hormone across the lung might be explained by degradation within the capillary lumen be endothelial cell surface peptidases or uptake onto specific receptors. The apparent gain of immunoreactive insulin across the lung might be due to displacement of immunoreactive exogenous hormone competing for receptor sites or modification of exogenous hormone by the lungs with increase in immunoreactivity.

Animals↗
PubMed1978

Immunoglobulin and complement deposits in the lungs of New Zealand Black/White mice.

Forty-four New Zealand Black/White (NZB/W) F1 hybrid mice were studied for evidence of immune complex deposition in the lungs and kidneys. Positive immunofluorescence was seen in the lungs of 27 mice. The pattern of lung fluorescence was granular in association with capillary walls in 16 mice and intracellular in 12. The incidence of granular fluorescence was increased with age and was seen in 80% of the lungs of mice over 13 months old. There was a correlation between capillary wall fluorescence in the lungs and the kidneys (P less than 0.001) and between lung cellular fluorescence and renal mesangial fluorescence (P less than 0.001). The role of immune complex deposition in human pulmonary disease is discussed.

Age Factors↗
PubMed1978

Depression of central respiratory drive by nitrazepam.

In a group of patients with chronic bronchitis, repeated night sedation with 10 mg nitrazepam produced a fall in central respiratory drive and a steady rise in arterial carbon dioxide tension. The changes produced over a five-day period were not clinically important, except in two patients who were already hypercapnic before receiving nitrazepam. The use of this drug in patients with carbon dioxide retention should be avoided.

Aged↗
PubMed1978

Comparison of reports on lung function tests made by chest physicians with those made by a simple computer program.

The numerical results of 60 sets of pulmonary function tests were submitted to five consultant chest physicians for independent reporting. The chest physicians' reports were compared with the reports generated by the on-line computer reporting system in routine use in the pulmonary function laboratory at Westminster Hospital. There was good agreement between the reports of the chest physicians among themselves and with the computer. The individual reports were compared with the consensus opinions of the physicians and the computer. The computer's decisions differed from the consensus opinion in 4.6% of instances. The comparable figures for the five physicians were respectively 2.9%, 2.9%, 2.9%, 4.0%, and 4.6%. Decisions differing from the consensus were due to mistakes or actual sustained disagreements of opinion. The physicians made more mistakes than the computer even though they were performing under test conditions. They made up for this, however, by producing fewer genuine disagreements from the consensus opinions. It is concluded that in routine day-to-day practice the computer report will be as consistently useful as the chest physicians' reports and more immediately available.

Airway Obstruction↗