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Biomedical subjects

S C Fagan

Publications and source records attributed to S C Fagan.

42 records · Page 3Linked to original sources
PubMed1988

The effect of beta-blockers on mental performance on older hypertensive patients.

This double-blind, three-way crossover study measured the influence of beta-blocker treatment on drowsiness and mental test performance in older hypertensive patients and determined if lipophilicity was a determinant of these effects. Twenty-seven hypertensive patients (mean age, 63 +/- 3 years) were studied. Patients received two weeks each of daily treatment with placebo, 100 mg of atenolol, or 150 mg of metoprolol tartrate and were evaluated on the 14th day of each treatment period, after which their next treatment period began. Mental performance was measured using Trails-A maze testing. Drowsiness was measured subjectively using a visual analogue scale, and objectively using critical fusion-frequency threshold testing. Blood pressure control was equivalent and clinically adequate in all subjects. Steady-state levels of metoprolol tartrate (235.7 +/- 46 ng/mL) and atenolol (453.6 +/- 56 ng/nL) achieved were those expected to produce similar beta-blockade. Mental performance as measured by Trials-A testing showed better scores during beta-blocker treatment compared with placebo. Trails-A scores improved as patients went from placebo to metoprolol treatment, but did not change as patients went from placebo to atenolol treatment. Critical fusion-frequency threshold measurements were lower following administration of both drugs than following that of placebo, but subjectively there was no difference in feelings of lethargy between either beta-blocker and placebo. These data show greater improvement in mental testing performance to be associated with metoprolol treatment, but neither produced more lethargy than placebo in elderly patients.

Aged↗
PubMed1987

Nimodipine disposition and haemodynamic effects in patients with cirrhosis and age-matched controls.

Six biopsy proven cirrhotics and five age-matched controls (mean 55.3 vs 52.4 years) were randomly given single 60 mg p.o. and 30 mg s.l. doses of nimodipine. Serum concentrations and blood pressure were measured regularly over the subsequent 24 h period. The clearance of nimodipine was reduced in the patients with cirrhosis. Apparent oral clearance of nimodipine in the cirrhotic group was significantly lower than that observed in the normal group (187 +/- 163 l h-1 vs 469.6 +/- 198.4 l h-1, P less than 0.01). There were no significant changes in mean arterial pressure (MAP) in the normal subjects. There were, however, significant reductions in MAP following oral nimodipine in the cirrhotics. These reductions were significantly related to nimodipine concentrations in individual patients (P less than 0.05).

Adult↗
PubMed1986

Prostanoid concentrations in human CSF following acute ischaemic brain infarction.

Thromboxane A2 and prostacyclin are two compounds which have been implicated as important modulators of local cerebral blood flow. Concentrations of the stable metabolites of these two compounds, thromboxane B2 and 6-keto-PGF1 alpha, were measured in cerebrospinal fluid (CSF) from eight acute ischaemic stroke patients and 14 patients with no evidence of cerebrovascular disease. Concentrations of thromboxane B2 ranged from 0.15 to 4.0 pg/ml and were significantly higher (P = 0.025) in the ischaemic stroke group when compared with the control group (0.1-0.3 pg/ml). Simultaneously acquired concentrations of 6-keto-PGF1 alpha were not elevated in the stroke group when compared to normals. These clinical findings support evidence from animal studies that emphasizes the importance of cerebral prostaglandins in mediating the secondary vascular changes of cerebral infarction. In conclusion there is an aberration in CSF thromboxane B2 concentrations in patients who have had a stroke. This may be an acute or chronic phenomenon.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Age and carotid artery occlusive disease are important determinants of cerebral blood flow changes after antihypertensive therapy.

STUDY OBJECTIVE: To determine the short-term effects of antihypertensive therapy on cerebral blood flow (CBF). DESIGN: Prospective, observational study. SETTING: A university-affiliated teaching hospital. PATIENTS: Twenty-four patients (age range 53-85 yrs) with chronic hypertension, nine of whom had carotid artery occlusive disease (CAOD). INTERVENTIONS: The CBF (xenon-133 inhalation technique) and blood pressure were measured before and at 60 minutes after administration of antihypertensive therapy. MEASUREMENTS AND MAIN RESULTS: Age was inversely related to the change in CBF in patients with CAOD (p < 0.01). In all patients, the change in CBF after taking antihypertensive drugs was significantly inversely associated with baseline CBF (p < 0.01). Changes in regional CBF, measured by asymmetry scores, were significantly greater in patients with CAOD than in those without CAOD (p < 0.05). CONCLUSIONS: Elderly patients with occlusive extracranial cerebrovascular disease are at risk of drug-induced changes in both mean and regional CBF, and may benefit from a CBF assessment before being prescribed antihypertensive therapy.

Age Factors↗
PubMedDate not supplied

Neuropsychological dose effects of a freon, trifluoromethane (FC-23), compared to N2O.

Animal studies show FC-23 to be a promising magnetic resonance imaging indicator of regional cerebral blood flow. In a Phase 1, dose ranging (investigative new drug) study, neuropsychological (NP) tests, subjective ratings, and intensive physiological monitoring were used to determine the maximum tolerated concentration of FC-23 for human application. Five normal healthy male volunteers were exposed to concentrations of FC-23 between 10% and 60% [randomly interleaved with exposures to both room air and 40% nitrous oxide (N2O)] in a within-subjects, double-blind design. Analyses of individual cases and ranked group data showed that individuals tolerated the 30% concentration of FC-23 according to established criteria. Planned comparisons indicated that inhalation of FC-23 produced smaller NP changes and fewer negative symptoms than 40% N2O but poorer NP performance and more negative symptoms than room air. This study indicated that FC-23 is not inert and that humans do not tolerate concentrations suitable for current MRI technology. NP and subjective data assisted in characterizing the sedative effect of FC-23.

Adult↗