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P Stanton

Publications and source records attributed to P Stanton.

22 records · Page 2Linked to original sources
PubMed1991

Theoretical and practical performance of magnetic stimulators and coils.

The diagnostic use of magnetic brain stimulation has not been extensive because of several technical drawbacks. These include the relatively low field strength and low repetition rate of available stimulators, design problems which can be resolved with the construction of stronger and faster magnetic stimulators. The present study details the design of a magnetic stimulator in two phases: energy storage and switching current; and the head or 'probe' design. The theoretical and practical implications of these design factors are discussed, and design effects on safety limits and stimulation parameters are also considered.

Electric Conductivity↗
PubMed1989

High-performance liquid affinity chromatography with phenylboronic acid, benzamidine, tri-L-alanine, and concanavalin A immobilized on 3-isothiocyanatopropyltriethoxysilane-activated nonporous monodisperse silicas.

Nonporous, microparticulate, monodisperse silicas with particle diameters between 0.7 and 2.1 microns are introduced as stationary phases in high-performance affinity chromatography. The immobilization of m-aminophenylboronic acid, p-aminobenzamidine, tri-L-alanine, and concanavalin A onto these silicas was successfully achieved using 3-isothiocyanatopropyl-triethoxysilane as an activation reagent. Immobilized phenylboronic acid was applied to the isolation of nucleosides, nucleotides, and glycoprotein hormones such as bovine follicotropin and human chorionic gonadotropin, while immobilized benzamidine was employed for the isolation of the serine proteases thrombin and trypsin, immobilized tri-L-alanine for the separation of pig pancreatic elastase and human leukocyte elastase, and immobilized concanavalin A for the isolation of horseradish peroxidase. In all affinity chromatographic systems studied, the nonporous monodisperse silicas showed improved chromatographic performance compared to results obtained with porous silica supports using identical activation and immobilization procedures. Furthermore, frontal analysis was used as a method to evaluate the influence of experimental parameters on biological activity and accessible ligand densities. Only minor changes in bioactivity were found with the nonporous affinity supports, where accessibilities were typically higher than ca. 60%. The immobilization of affinity ligands onto porous supports as used in this and associated papers thus represents a successful general procedure for the preparation of stable matrices with fast kinetics for use in high-performance affinity chromatography.

Alanine↗
PubMed1987

Bioequivalence study of nabumetone: tablet versus suspension.

The orally administered tablet and suspension of the analgesic drug nabumetone (Relafen), a novel naphthylalkanone, were tested for bioequivalence. Nabumetone is rapidly metabolized to an active metabolite, 6-methoxy-2-naphthylacetic acid (BRL 10720). The pharmacokinetics of the metabolite were studied in 24 healthy adult male volunteers. Each received a 1-g dose of the nabumetone formulations in a balanced, randomized, two-way crossover investigation. Serum metabolite concentrations were determined over a 120-hour interval by high-performance liquid chromatography. The values of the pharmacokinetic parameters computed for tablet and suspension are presented in that order: area under the curve = 1,269:1,338 mg.hour/ml; absorption half-life = 1.04:0.83 hour; elimination half-life = 27.16:25.15 hours; lag time = 0.19:0.07 hour; peak concentration = 27.56:31.91 micrograms/ml, and time to peak concentration = 4.99:4.17 hours. The mean concentration of BRL 10720 was found to be higher during the first eight hours for the suspension than for the tablet. Using criteria for statistical significance, the values for peak concentration, time to peak concentration, elimination half-life, and lag time were found significant (p less than 0.05). These results may well be reflecting the increased absorption characteristics of the suspension due to the pharmaceutical characteristics of the preparation. The formulations were found to be bioequivalent when compared on the premise that no significant difference was detected when area under the curve and all other parameters were compared, based upon the 75/75 rule analysis.

Adult↗