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Biomedical subjects

R Turner

Publications and source records attributed to R Turner.

At least 325 records · Page 18Linked to original sources
PubMed1972

The pathogenesis of esophageal dysfunction in scleroderma and Raynaud's disease.

To determine the pathogenesis of esophageal dysfunction in scleroderma and Raynaud's disease, the lower esophageal sphincter (LES) was tested with: (a) methacholine acting directly at the cholinergic receptor on the muscle; (b) edrophonium, a cholinesterase inhibitor, enhancing the effect of released acetylcholine; and (c) gastrin I, acting through the release of acetylcholine. 10 patients with Raynaud's disease and 22 patients with scleroderma were compared with 20 normals and 20 patients with isolated LES incompetence. The mean basal LES pressure in normals was significantly greater than that recorded in both patients with scleroderma and Raynaud's disease. Six patients having scleroderma with normal peristalsis had an LES pressure significantly greater than that noted in 16 patients having scleroderma with abnormal peristalsis. In all groups, the per cent increase in LES pressure was similar when tested by direct muscle stimulation by methacholine. The response to agents that acted indirectly through intact cholinergic nerves differed in these groups. The LES response to gastrin I distinguished patients with normal peristalsis from those with abnormal peristalsis. The patients with normal peristalsis, either with scleroderma or with Raynaud's disease showed only a partial reduction in their response to gastrin I. The response to gastrin I was markedly reduced only in patients with abnormal peristalsis. These data indicate that in patients with scleroderma and Raynaud's disease, the LES response to direct muscle stimulation by methacholine was intact while the response to gastrin I and edrophonium was diminished.

Adult↗
PubMedDate not supplied

Steady state relative bioavailability and pharmacokinetics of oral propranolol in black and white North Americans.

The steady state bioavailability and pharmacokinetics of propranolol over two consecutive dosing intervals were investigated in 18 black and 10 white normal volunteers following the administration of 20 mg of a test and reference oral dosage form, respectively, every 6 h. There were no differences (p greater than 0.05) between dosage forms in the mean (n = 28) area under the plasma concentration-time curve (AUC), maximum plasma concentration (Cmax) or time to Cmax (tmax) for propranolol or its active metabolite, 4-hydroxypropranolol. However, as a group blacks had lower plasma concentrations of propranolol during the second dosing interval (AUC-2 and Cmax-2, respectively) were significantly (p less than 0.05) lower in blacks, but there were no ethnic differences (p greater than 0.05) in tmax. The mean AUC and Cmax for the 4-hydroxylated metabolite during both dosing intervals were significantly (p less than 0.05) lower in blacks. Mean oral clearances of propranolol, assuming complete absorption, (range: 42.1-54.5 ml min-1 kg-1) were similar (p greater than 0.05) in each racial group. There were no substantial changes in heart rate or blood pressure in blacks or whites following propranolol administration. These data suggest that for oral propranolol, blacks have different absorption and disposition characteristics than whites.

Administration, Oral↗