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Biomedical subjects

S H Jackson

Publications and source records attributed to S H Jackson.

At least 91 records · Page 5Linked to original sources
PubMed1984

Is circadian variation in theophylline trough serum concentrations determined by time of dosing?

Ten healthy volunteers were each given two separate courses of eight doses of theophylline 200 mg as a slow release preparation at 12 hourly intervals. In the first course (regimen 1) the dose was given at 11.00 h and 23.00 h and in the second (regimen 2) at 05.00 h and 17.00 h. Sixty hours after the start of each course, four consecutive trough serum theophylline concentrations were measured. On regimen 1 the trough concentration of theophylline was 6.2 +/- 2.2 mg/l (mean +/- s.d.) at 11.00 h compared with 5.4 +/- 1.9 mg/l at 23.00 h (P less than 0.01). This circadian variation was abolished during regimen 2 when the mean theophylline concentrations were identical at 5.2 mg/l. The higher trough concentrations after the evening dose on regimen 1 and the loss of circadian variation on regimen 2 may be due to the change in sleep period in relation to the time of dosing.

Circadian Rhythm↗
PubMed1983

Sustained serum theophylline concentrations during chronic twice daily administration of a slow release preparation.

Theophylline concentrations were measured in a clinical setting in 15 patients given a slow release theophylline preparation (Theo-Dur) every 12 h for reversible obstructive airways disease. Doses of 300-600 mg (464 +/- 134), 12 hourly, resulted in mean serum concentrations which increased from 11.2 +/- 2.9 micrograms/ml at 0 h to a peak of 15.5 +/- 4.6 micrograms/ml at 6 h and decreased again to 10.4 +/- 2.9 micrograms/ml at 12 h. The mean percentage fluctuation of serum concentrations (maximum minus minimum expressed as a % of the maximum) was 38.6 +/- 10.1%, range 20.3% to 54.9%. There was a significant positive correlation between % fluctuation and theophylline steady-state clearance determinations. Excluding a single heavy smoker, theophylline clearance also showed a significant inverse relationship with age. These data suggest that when this slow release preparation is given 12 hourly, satisfactorily sustained serum theophylline concentrations will be achieved in most adults.

Adult↗
PubMed1983

Indomethacin does not attenuate the effects of hydralazine in normal subjects.

Indomethacin 100 mg/day or matching placebo was given for 2.5 days to 9 healthy volunteers in a double-blind cross-over study, followed by an intravenous injection of 0.2 mg/kg of hydralazine. Compared to placebo, indomethacin produced no statistically significant change in pulse rate or blood pressure in both standing and supine positions. Hydralazine injection was followed by a statistically significant fall in lying and standing diastolic pressure and a rise in lying and standing pulse after both indomethacin and placebo pretreatments. There were no significant differences in these effects following indomethacin compared to placebo pretreatment. These results do not support the hypothesis that endogenous prostaglandins are involved in the mechanism of action of hydralazine.

Adult↗
PubMed1983

Comparison of the effects of single doses of atenolol and labetalol on airways obstruction in patients with hypertension and asthma.

1 The effects of atenolol (100 mg), a cardioselective beta-adrenoceptor blocking agent, and labetalol (300 mg), a combined alpha- and non-selective beta-adrenoceptor blocking agent given in single doses were examined in a double-blind placebo controlled study in 11 asthmatic patients with hypertension. Changes in forced expiratory volume in one second (FEV1) were measured. 2 There were no significant differences between the effects of the active drugs, approximately half the patients having higher FEV1 values during each of the two active treatments. When compared with placebo, labetalol significantly reduced the effect of inhaled salbutamol on FEV1. 3 Whilst beta-adrenoceptor blockings drugs cannot be recommended in patients with airways obstruction, should they inadvertantly be given, labetalol like atenolol may be considered relatively safer then pure non-selective beta-adrenoceptor blocking drugs.

Adult↗
PubMed1983

A comparison of diclofensine and desmethylimipramine using tyramine pressor tests in normal subjects.

Eight male volunteers received placebo, diclofensine 25 mg, diclofensine 50 mg and desmethylimipramine (DMI) 50 mg at least a week apart. Using tyramine pressor tests, no statistically significant differences between the noradrenaline reuptake blocking effects of the three active treatments could be demonstrated. Visual analogue rating scales showed an increase in dryness of the mouth at 3 h after DMI but no similar effect after either dose of diclofensine.

Adult↗
PubMed1983

Blood pressure in black, white and Asian factory workers in Birmingham.

A screening survey was conducted among factory workers, aged 15-64 years, in Birmingham, England to investigate ethnic differences in blood pressure. One-thousand and forty-nine subjects (784 men, 265 women) were screened, representing 79% of the eligible population. Mean systolic and diastolic blood pressures generally did not differ between men of black West Indian (n = 173), local white (n = 439) or Asian (n = 172) origin, when matched by 10-year age groups. Analysis of covariance using age as the covariate revealed that, overall, Asian men had significantly lower systolic but higher diastolic pressures than the other ethnic groups. The proportion of men arbitrarily defined as hypertensive (greater than or equal to 160 mmHg systolic or greater than or equal to 95 diastolic or blood pressures below this figure whilst receiving antihypertensive therapy) was 26% of West Indians, 22% of whites and 17% of Asians, but these were not significantly different when age was accounted for. Black West Indian women (n = 101) did have higher diastolic pressure than white women (n = 164), but this difference was dependent on body mass index. Overall, systolic pressures in women were not significantly different. These findings differ from those consistently reported from the United States.

Adolescent↗
PubMed1983

The Birmingham blood pressure school study.

Four-hundred and twenty-eight school leavers of 3 ethnic groups (white, black and Asian) were screened for blood pressure, resting pulse rate and general anthropometric characteristics. Asian pupils were both shorter and lighter than the other two groups whilst black males were heavier and taller. There was no significant difference in the mean systolic or diastolic blood pressure between the 3 groups, although the black pupils had a stronger family history of hypertension, particularly on the mother's side. These observations differ in some respects from other ethnic blood pressure studies and establish values for the local population.

Adolescent↗
PubMed1983

Ethnic differences in peak expiratory flow rate in Birmingham factory workers.

Among 698 Birmingham factory workers, Asian men (n = 75) tended to have lower peak expiratory flow rates (PEFR) than black (n = 156) or white (n = 138) men when age, height and smoking habits were accounted for. This trend reached statistical significance in Asian females (n = 20), despite a small sample size. There were no significant differences in PEFR between blacks and whites of either sex.

Adult↗
PubMed1983

A case of congenital triple valve disease.

We report a case of congenital triple valve stenosis with dominant pulmonary valve disease, sparing the aortic valve, presenting at the age of 51 years with progressive shortness of breath and central cyanosis. At post mortem, no intracardiac right to left communication could be demonstrated.

Female↗
PubMed1983

Prescribing habits for theophylline preparations.

Information concerning the prescriptions for theophylline preparations for a group of 80 inpatients and 55 outpatients were examined. Slow-release preparations were overwhelmingly preferred. The majority of patients were receiving low daily doses of theophylline or equivalent, and serum drug level monitoring was almost non-existent.

Adolescent↗
PubMed1981

Does long-term low-dose corticosteroid therapy cause hypertension?

1. One hundred and ninety-five patients undergoing low-dose prednisone or prednisolone therapy were investigated. Blood pressure, weight, serum urea, sodium and potassium were recorded before therapy and again after at least 1 year of therapy. 2. The rise in both mean systolic and mean diastolic blood pressure was paralleled by an increase in the prevalence of arbitrarily defined hypertension. 3. There was no relationship between change of blood pressure and either dose of corticosteroid or duration of therapy. Blood pressure before therapy was the main determinant of the change in blood pressure. 4. Mean serum sodium levels rose slightly but serum potassium levels did not change during the follow-up period. There was no significant weight gain. 5. These results indicate that treatment of asthma and rheumatoid arthritis with prednisolone or prednisolone in low dose does not cause hypertension or biochemical features suggestive of mineralocorticoid excess.

Dose-Response Relationship, Drug↗