Biomedical subjects
T Fraser
Publications and source records attributed to T Fraser.
Conventional and controlled release diltiazem. Bioavailability in healthy volunteers and anti-anginal effects in combination with metoprolol in stable angina pectoris.
Diltiazem CR tablets 120 mg b.i.d. for 1 week were compared with plain tablets 60 mg q.i.d. in 13 healthy male volunteers in a study of pharmacokinetic variables. Their antianginal efficacy was also compared in 23 patients with stable angina pectoris who were already on metoprolol. Both studies were of randomised, cross over design, and the clinical study was double blind. The pharmacokinetic variables of the two formulations were very similar except for the longer tmax of 4.4 h for diltiazem CR in comparison to 2.9 h for the plain tablets. The mean relative bioavailability of diltiazem CR in comparison with plain tablets was 1.14. The clinical study showed that after four weeks on diltiazem CR 120 mg b.i.d. or diltiazem plain tablets 60 mg q.i.d. in addition to metoprolol, there were significant decreases in weekly anginal attacks from 11 to 5 attacks/week, the number of nitroglycerin tablets consumed from 6 to 3 tablets/week, and an increase in the maximum workload from 116 to 126 and 123 W for diltiazem CR and plain diltiazem tablets, respectively, as compared to placebo. Five of the patients were angina free during diltiazem treatment. No difference in anti-anginal efficacy between the two preparations was seen. It was concluded that CR 120 mg b.i.d. appears bioequivalent to plain diltiazem tablets 60 mg q.i.d.
An alarm for monitoring CPAP.
We have built a device for use within the hospital and at home that is designed to warn of circuit disconnection when used in conjunction with continuous positive airway pressure (CPAP) therapy delivered via ventilators or CPAP generating systems. The Royal Children's Hospital CPAP alarm is a compact, battery operated alarm and monitor of circuit pressure. The device includes intrinsic safety features including a safety blow-off valve, a high pressure alarm and design features that make the device practical, safe and easy to use by both trained hospital personnel and home care attendants with limited training.
Heterogeneous estrogen receptor levels detected via multiple microsamples from individual breast cancers.
Twenty-six surgical breast cancer specimens were subjected to multiple estrogen receptor (ER) assays with a microsample technique. In most tumors there were large variations in ER levels in samples taken from different regions of the same tumor. After correction of individual samples for differences in carcinoma content, such variations were not abolished. Nine of the 26 breast cancers, although positive overall, were devoid of ER in some regions. For ER-positive tumors the average coefficient of variation (CV) for intratumor ER levels was 86%, with a range from 25% to 200%. This is well above the CV obtained with repeat samples of homogeneous tissue (14%). These results suggest that many ER-positive cancers may be composed of cells with a variety of ER levels. An assessment of individual intratumor ER variability may have biologic and clinical significance.
The Islets of Langerhans in Relation to Diabetes.
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Report on the Progress of Physiology.
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Dexamethasone-induced hypertension in the rat: effects of L-arginine.
1. The effects of L-arginine treatment on dexamethasone-induced hypertension were examined in the Sprague-Dawley rat. Seventy rats were randomly divided into the following eight groups: sham, dexamethasone (5 and 10 micrograms/day, L-arginine (100 and 500 mg/kg per day), L-arginine (100 or 500 mg/kg per day) + dexamethasone (10 micrograms/day), L-arginine (520-797 mg/kg per day in food) + dexamethasone (5 micrograms/day). Systolic blood pressure (SBP), bodyweight and plasma nitrate/nitrite concentration were measured. 2. Dexamethasone (5 and 10 micrograms/day) increased SBP in both sham and L-arginine-treated rats. Dexamethasone at 10 micrograms/day decreased bodyweight, but did not alter plasma nitrate/nitrite concentrations. 3. L-Arginine (500 mg/kg per day, i.p.) increased plasma nitrate/nitrite concentrations in 10 micrograms/day dexamethasone-treated rats. L-Arginine did not alter blood pressure in either sham or dexamethasone-treated rats. 4. Dexamethasone-induced hypertension differs from adrenocorticotropic hormone (ACTH)-induced hypertension in the rat in that it is not modified by L-arginine. Thus, ACTH-induced hypertension cannot be explained simply in terms of glucocorticoid activity.