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Biomedical subjects

C F George

Publications and source records attributed to C F George.

At least 145 records · Page 8Linked to original sources
PubMed1978

Contribution of individual differences in gastric emptying to variability in plasma propranolol concentrations.

1 No correlation was found between the rate of gastric emptying and peak plasma propranolol concentrations in six hypertensive patients after single oral doses of 80 mg. 2 In four normal subjects given oral propranolol the peak plasma concentration was highest when a simultaneous injection of metoclopramide and lowest when propantheline was given. The mean time to peak was 1.5 h after metoclopramide, 2.8 h after normal saline and 4.5 h after propantheline. 3 Gastric emptying has some influence on the time of peak plasma propranolol concentrations but individual variation in its bioavailability is determined mainly by first-pass metabolism in the liver.

Administration, Oral↗
PubMed1977

A second look at emepronium bromide in urinary incontinence.

Response to oral and intramuscular emepronium bromide was assessed cystometrically in nine patients with urinary incontinence caused by an uninhibited bladder. Oral therapy had no effect, whereas intramuscular administration increased bladder capacity and significantly delayed the onset of bladder spasm and the desire to void. Plasma-propranolol response was delayed and concentrations were reduced after an oral 40 mg dose of propranolol in 3 patients who had received oral emepronium bromide. These results indicate that although oral emepronium bromide had some anticholinergic effect--i.e., in reducing gastrointestinal motility--absorption of an oral dose was not sufficient for the bladder to be affected.

Administration, Oral↗
PubMed1977

Increased sensitivity to nitrazepam in old age.

The effects of a single 10 mg oral dose of nitrazepam were compared with those of a placebo in healthy young and old people. Both the young and the elderly slept better on three successive nights after nitrazepam but they felt less awake at 12 and 36 hours (P less than 0-01). Elderly people made significantly more mistakes in a psychomotor test than did the young, despite similar plasma concentrations of nitrazepam and half lives in the two groups. This difference in response to psychomotor testing is probably explained by an increased sensitivity of the ageing brain to the action of nitrazepam.

Adult↗
PubMed1977

A comparison of once and twice daily atenolol in hypertension.

The hypertensive action of atenolol has been studied in a randomized double-blind crossover comparison. Twelve patients showed a highly significant reduction in average supine systolic and diastolic blood pressures from pre-treatment values of 196.3/115.9 to 159.1/89.2 mmHg (26.1/15.4 kPa to 22.2/11.9 kPa) after 2 weeks on once daily atenolol. No dose-related reduction in blood pressure was seen and the single 100 mg daily dose was as effective as 100 mg twice daily or 50 mg twice daily. Blood pressures recorded after 2 weeks' atenolol were lower than those obtained at 7 days irrespective of dose.

Adult↗
PubMed1976

Reduced respiratory responses to carbon dioxide after propranolol: a central action.

In a double-blind study in six subjects propranolol significantly reduced the respiratory sensitivity to carbon dioxide rebreathing. This effect seems to have been due to beta-adrenergic blockade, since it was not seen with D-propranolol. In two subjects increasing doses of propranolol caused progressive reductions in respiratory sensitivity to values below normal and similar to those of patients with ventilatory failure. These changes are probably due to a central action of propranolol.

Adult↗
PubMed1976

Trial of combination of guanethidine and oxprenolol in hypertension.

Thirteen hypertensive patients entered a double-blind crossover trial of guanethidine and oxprenolol in combination. In nine patients who completed the trial there was an additive effect on blood pressure, but the combination had a smaller effect on heart rate than was expected from the individual effects, and side effects were not increased. During treatment with oxprenolol the plasma potassium concentration rose from 3.6 mmol (mEq)/1 to 3.9 mmol (mEq)/1. No correlation was found between the plasma oxprenolol concentration and changes in blood pressure or response to injected isoprenaline, but measurements of plasma oxprenolol concentrations were of value in determining compliance with the protocol.

Blood Pressure↗
PubMed1976

Comparison of the effects of atenolol and practolol on exercise tachycardia in normal subjects.

The relationship between cumulative doses of practolol and atenolol and resultant decreases in exercise tachycardia has been examined in 4 healthy volunteers. Continuous intravenous infusions of practolol (0.4 mg/kg), atenolol (0.12 mg/kg) and saline were administered between 7 and 12 minutes of bicycle exercise. The mean (+/- S.E.M.) heart rate (HR) at 7 min. for practolol (133 +/- 5.1) and atenolol (132 +/- 2.8) were significantly (p less than .01) reduced to 115 +/- 2.3 and 104 +/- 2.9 beats/min. respectively. The pre-infusion HR in the saline study (132 +/- 1.2) was unchanged (133 +/- 4.6) at 12 min. The relationship between the log cumulative dose of each drug and the per cent fall in HR/min was linear for each subject. The log dose-response curve (mean of 4 subjects) for practolol (y = 9.6x + 18.1) was more horizontal than for atenolol (y = 18.4x + 38.6).

Adult↗
PubMed1975

Absorption and metabolism of nicotine from cigarettes.

Eight men volunteers each smoked a single cirgarette containing 14C-nicotine and gave arterial blood samples during and for 50 minutes after smoking. The maximum concentration of nicotine in the arterial blood ranged from 31 to 41 mug/l in four regular cigarette smokers who inhaled. Two non-smokers achieved maximum levels of 2 and 4 mug/l. On a separate occasion two of the inhalers received 1 mg. 14C-nicotine in 10 divided doses injected intravenously. In both cases the peak arterial nicotine concentrations bore a similar relationship to the intravenous dose, as did the peak nicotine concentrations to the retained doses during smoking.

Absorption↗
PubMed1975

A comparison of propranolol and compound RO3-4787 in the treatment of arterial hypertension in man.

1. The effects of propranolol and RO3-4787, a new beta-adrenoceptor antagonist with a partial agonist activity, have been studied in a blind, cross-over comparison with placebo. 2. In ten patients who completed the study, the two drugs produced a similar reduction in blood pressure; the reduction in heart rate with propranolol was significantly (P less than 0.001) greater than that produced by RO3-4787. 3. Plasma renin activity averaged 4.13 +/- 1.37 ng h-1 ml-1 on placebo, fell to 3.64 +/- 1.47 ng h-1 ml-1 on propranolol and to 2.50 +/- 1.39 ng h-1 ml-1 on RO3-4787. 4. No correlation was demonstrable between the log plasma concentration of either propranolol or RO3-4787 and change in blood pressure.

Adult↗
PubMed1975

Clinical experience with use of ultrasound sphygmomanometer.

The performance of an ultrasound sphygmomanometer (Arteriosonde 1217) has been compared with that of the London School of Hygiene and Tropical Medicine and Hawksley sphygmomanometers. The Arteriosonde gave closely similar values of systolic blood pressure of the other instruments but diastolic blood pressure lay midway between phase 4 and phase 5 of the Korotkoff sounds. Observers using the Arteriosonde showed a significant preference for even terminal digits.

Blood Pressure Determination↗