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Biomedical subjects

C Davidson

Publications and source records attributed to C Davidson.

At least 109 records · Page 6Linked to original sources
PubMed1978

The effects of potassium supplements, spironolactone of amiloride on the potassium status of patients with heart failure.

Extra potassium supplements, spironolactone or amiloride were given for 5 months to forty-nine patients with heart failure who were taking furosemide and were in a steady state. Plasma potassium increased with all three treatments but there was no significant increase in total body potassium or red cell potassium. These findings together with other studies suggest that patients with heart failure taking diuretics do not have a significant depletion of body potassium.

Adult↗
PubMed1976

Effect of long-term diuretic treatment on body-potassium in heart-disease.

Plasma and total body potassium have been measured in 151 patients with chronic heart-disease, 83 of whom were taking diuretics and potassium supplements. After allowance for age and body-size, the deficit in total body-potassium was only 3-5% (100-150 mmol) in the diuretic group. 13 of the 83 patients taking diuretic had hypokalaemia (less than 3-5 mmol/1) but the potassium deficit was no greater than in the patients with normal plasma-potassium. There was no relation between the dose of potassium supplements and either the plasma-potassium or the total body-potasium. It is suggested that potassium depletion is not a major problem in patients with heart-failure treated with diuretics. The dose of potassium supplements should therefore be determined entirely by the plasma-potassium.

Adult↗
PubMed1976

Comparison of antihypertensive activity of beta-blocking drugs during chronic treatment.

The hypotensive activity of five beta-adrenoceptor antagonists with different ancillary pharmacological properties was compared in a randomised double-blind factorial trial in 25 untreated patients with stable, uncomplicated essential hypertension. In doses that produced similar reductions in exercise tachycardia all drugs had similar blood-pressure lowering activity, greater on systolic than diastolic pressure and greatest during exercise. With the exception of vasodilator activity the possession of any particular combinaton of ancillary pharmacological properties did not significantly influence the specific antihypertensive activity of these compounds.

Adrenergic beta-Antagonists↗
PubMed1976

Diurnal pattern of water and electrolyte excretion and body weight in idiopathic orthostatic hypotension. The effect of three treatments.

The diurnal pattern of water and solute excretion and body weight were examined in five control subjects and in a patient with idiopathic orthostatic hypotension before and during treatment. The patient had a reversed diurnal pattern of excretion of sodium, urea and water but not of potassium and creatinine, and there was an excessive diurnal variation in body weight. The effects of three treatments, high salt diet alone and then with the addition of head-up tilt, and later fludrocortisone, were studied. Fludrocortisone caused marked clinical improvement and retention of sodium and water. Once a steady state was achieved none of the treatments had any significant effect either on the diurnal variation in weight or on the water and solute xcretion pattern except for a small reduction in sodium excretion at night when the patient slept with a head-up tilt. In is concluded that these treatments cause symptomatic improvement in idiopathic orthostatic hypotension through an increase in extracellular fluid volume rather than through any change in the abnormal diurnal pattern of water and salt excretion.

Aged↗
PubMed1976

Comparative anti-hypertensive effectiveness of beta-adrenoreceptor antagonists with different pharmacological properties: dose-response studies during acute and chronic administration.

1. Immediate and long-term blood pressure-lowering activity of five beta-adrenoreceptor antagonists with different ancillary pharmacological properties were compared in a randomized double-blind placebo controlled factorial trial in twenty-five previously untreated patients with stable uncomplicated essential hypertension. 2. In doses which produced similar reductions in exercise tachycardia, all drugs exerted similar anti-hypertensive activity, which was greater on systolic than diastolic pressure and greatest during exercise. 3. These effects were maximum within an hour and lasted for over 8 h after a single oral dose. 4. Blood pressure-lowering activity, particularly the reduction in exercise systolic pressure, was significantly related to the logarithm of the dose of each drug. 5. Anti-hypertensive activity was maximally enhanced after 4 weeks of sustained treatment at any given dose. There was no short-term habituation to treatment and substitution with placebo resulted in a return of the blood pressure to pretreatment values within 4 weeks without subsequent overshoot. 6. The blood pressure-lowering activity of these drugs was predominantly related to their common property of competitive antagonism of cardiac beta-adrenoreceptors; their ancillary pharmacological properties, with the exception of intrinsic vasodilator activity, played little part in this response.

Adrenergic beta-Antagonists↗
PubMed1975

Temporo-mandibular joint disease in ankylosing spondylitis.

The occurrence of temporo-mandibular joint (TMJ) disease in ankylosing spondylitis is not widely recognized and its incidence is disputed. Seventy-nine patients attending two routine rheumatology clinics were therefore examined by dental surgeon and nine (11-5 per cent) were considered to have specific TMJ involvement. These patients were older than the remainder, and had more extensive spinal and peripheral joint disease. Symptoms were mild and the predominant clinical feature was restricted mouth opening, which could present considerable difficulties during emergency anaesthesia. Bilateral condylectomy was undertaken in one patient with some benefit.

Adult↗
PubMed1975

A comparative study of the activity of beta-adrenoceptor antagonists in man.

1. In healthy subjects the plasma concentration of unchanged drug, heart rate response to excerise and attenuation of isoprenaline tachycardia were maximal at one hour after ingestion of a range of doses of propranolol, oxprenolol, practolol, tolamolol, atenolol and metoprolol. 2. There was a within-drug relationship between plasma concentration of unchanged drug and the attenuation of exercise and iosprenaline tachycardia. There was no similar between-drug relationship. 3. There was a similar exponential relationship between oral dose and reduction of exercise tachycardia for all six drugs. 4. The linear relationship between oral dose and antagonism of infused isoprenaline was significantly greater for oxprenolol and propranolol than for the other four drugs. 5. "Cardioselective" activity was the only ancillary pharmacological property which differentiated the activity of these drugs in normal subjects.

Adrenergic beta-Antagonists↗