Noninvasive assessment of the haemodynamic effects of nicardipine in normotensive subjects.

Calcium antagonists reduce myocardial contractility in vitro. Nicardipine is a dihydropyridine derivative with enhanced selectivity for vascular smooth muscle. We have studied the pharmacokinetics and the haemodynamic effects that occur in man following bolus intravenous administration of nicardipine.

Evidence of parasympathetic activity of the angiotensin converting enzyme inhibitor, captopril, in normotensive man.

Captopril (50 mg orally) produced a significant fall in systolic and diastolic blood pressure in six normotensive sodium replete subjects, without a rise in heart rate. On captopril, there was no change in the expected normal increase in heart rate on standing. Supine plasma noradrenaline was not reduced by captopril and normal postural increases were maintained.

Pharmacodynamics and population pharmacokinetics of enalapril and lisinopril.

The di-acid metabolite of enalapril, enalaprilat, and its lysine analogue lisinopril are potent inhibitors of angiotensin converting enzyme (ACE); they do not contain sulphydryl groups. Both drugs can be assayed by high pressure liquid chromatography and by radioimmunoassay and plasma ACE inhibition remains stable under normal storage conditions. It is therefore possible to study their pharmacokinetics as well as their pharmacodynamic effects in man.

Withdrawal reactions following cessation of central alpha-adrenergic receptor agonists.

Interruption of long-term treatment with alpha 2-adrenergic receptor agonists may be associated with reversal of their hemodynamic effects, clinical and biochemical evidence of increased peripheral sympathetic activity, and behavioral responses similar to those seen after narcotic or alcohol withdrawal. Reactions are most commonly observed after short-acting imidazoline drugs such as clonidine and tiamenidine. Reactions are less common after longer acting agents such as guanfacine.

Medical information system training: an analysis of the reactions of hospital employees.

Six months after the implementation of a medical information system (MIS) employees were questioned concerning their evaluation of the training they received. Wide variability is observed in the range of employee responses to questions addressing their: satisfaction with the training experience, desire for any additional training, ease of learning to use the system, and level of felt competence in currently using the system. The results of stepwise regression analyses of the response patterns indicate that personality traits, attitudes toward automation, and work history variables are key factors in explaining why employees have different reactions to training.

Kinetics of lead following intravenous administration in man.

Whole body retention of lead (Pb) and lead kinetics in blood, urine and faeces were determined over 2 weeks following i.v. administration of 203Pb-labelled chloride to 2 subjects.

Comparison of fentanyl and halothane supplementation to general anaesthesia on the stress response to upper abdominal surgery.

The stress response to surgery and anaesthesia was studied in 20 patients undergoing cholecystectomy or vagotomy and pyloroplasty. Patients were anaesthetized with thiopentone and nitrous oxide; 10 patients received supplements of 0.5-1.

Enalapril and autonomic reflexes and exercise performance.

Enalapril (10 mg), in young sodium replete normotensive males significantly reduced systolic and diastolic blood pressures in both the supine and erect posture without orthostatic effects. As with captopril (25 mg) erect and supine heart rate did not differ from that after inactive placebo even at the time of maximum blood pressure reduction. The absence of reflex bradycardia was not related to a sympatho-inhibitory effect as the responses to Valsalva's manoeuvre, cold stress and dynamic and isometric exercise were unchanged by enalapril.

Implementation of a medical information system: evaluation of adaptation.

A study was conducted to explain variability in hospital employee responses to the implementation of a medical information system. Results showed that 28 to 35 percent of the variance in adaptation was explained by the predictor variables, and that the significant variables were attitudes toward computers in general, role ambiguity, personality attributes, the person's work shift and previous history of job mobility.

Effects of captopril, an angiotensin-converting enzyme inhibitor, in normotensive sodium-replete volunteers.

Captopril (SQ 14 225) was administered to normotensive, sodium-replete volunteers in order to investigate the relationships between its haemodynamic effects and effects on sympathetic activity, the renin-angiotensin-aldosterone system, and plasma-converting enzyme activity. Following the administration of captopril (25 mg) orally, mean arterial pressure fell (supine 89.1 +/- 5.

Effects of the angiotensin converting enzyme inhibitor, captopril, in essential hypertension.

1 The effects of the orally active angiotensin converting enzyme inhibitor, captopril, were examined in 15 patients with mild or moderate essential hypertension. 2 Following initial dosing with captopril 25 mg, there was a significant fall in supine and erect blood pressure in 2 h and lasting for 6 h. There was no significant alteration of heart rate.

The influence of protein binding on disopyramide clearance.

Individual disopyramide clearance is not constant and previous studies have suggested that this may be time and/or concentration dependent. Steady state disopyramide concentrations were achieved in six volunteer subjects at each of three infusion rates. Drug analysis was by HPLC and protein binding was determined by ultrafiltration.

Protein binding of piretanide in normal and uraemic serum.

The protein binding of piretanide was assessed by continuous ultrafiltration of sera from six normal subjects and seven uraemic subjects (samples taken immediately pre-dialysis). Throughout the range of piretanide concentrations studied (0.5-4.

Alleviation of α-tomatine-induced toxicity to the parasitoid,Hyposoter exiguae, by phytosterols in the diet of the host,Heliothis zea.

The solitary, endoparasitic ichneumonid,Hyposoter exiguae (Viereck) is a parasitoid of the tomato fruitworm,Heliothis zea (Boddie). However, the parasitoid is deleteriously affected by the tomato glycoalkaloid, α-tomatine, ingested from hosts (H. zea) fed on artificial diets or semipurified extracts of tomato plants that contained α-tomatine.

Lead exposure and renal failure: does renal insufficiency influence lead kinetics?

Blood and urine lead concentrations have been measured in 40 subjects with normal and impaired renal function. Derived renal lead clearance varied widely, but was not influenced by the degree of renal impairment. Lead, however, appeared to reduce its own clearance.

Effect of iron poly (sorbitolgluconic acid) complex on urinary cellular excretion.

The intramuscular injection of 250 mg iron poly (sorbitol-gluconic acid) complex caused no increase in urinary cellular or bacterial excretion in 8 patients with chronic pyelonephritis, 4 patients with non-infective renal disease, and 4 controls. However, in 4 patients with chronic infective disease of the renal tract given 500 g there was a significant increase in cellular excretion. This response was not seen in 2 control patients, nor in 2 patients with non-infective renal disease.

Changes in blood pressure, heart rate, and sympathetic activity on abrupt withdrawal of tiamenidine (HOE 440) in essential hypertension.

A limitation of clonidine therapy is the syndrome of rebound hypertension and sympathetic overactivity after withdrawal. Ten patients, four male, six female, aged 28--64 years, with essential hypertension, were treated for one year with an imidazoline derivative, tiamenidine. Blood pressure fell from an average of 178/108 mm Hg pretreatment to 152/86 mm Hg after 1 year.

A pharmacokinetic and clinical evaluation of iron poly (sorbitol-gluconic acid) complex.

The pharmacokinetics of iron poly (sorbitol-gluconic acid) complex (IPSG) were studied following a single intramuscular injection of 59Fe-labelled IPSG to 4 iron deficient-patients. The results showed a more rapid uptake of iron from the site of injection than that reported with iron dextran while there was a lower urinary excretion than found with iron sorbitol citrate. A clinical study was carried out in 11 patients with iron deficiency anaemia.