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Biomedical subjects

S W McClean

Publications and source records attributed to S W McClean.

7 recordsLinked to original sources
PubMed1984

Etretinate: effect of milk intake on absorption.

Since etretinate, an aromatic retinoid useful in the treatment of psoriasis and other skin disorders is lipid-soluble, it may be poorly absorbed in the absence of a fat load. We therefore studied serum concentrations of etretinate and its major metabolite (Ro 10-1670) after the controlled administration of etretinate. After an overnight fast, 6 Darier's disease and 4 psoriatic patients received a 1 mg/kg morning dose of etretinate with water or 1 pint of whole milk (fat load). There was a 260% increase (p less than 0.0005) in the mean of each patient's increase in the baseline-corrected peak serum concentration of etretinate after administration with milk (115 +/- 15 micrograms/dl) compared to after administration with water (32 +/- 4 micrograms/dl). Over a 24-h period there was an overall 296 +/- 26% (p less than 0.0005) increase in serum etretinate after administration with milk compared to water in 5 patients with Darier's disease. In contrast to the serum etretinate, there was a 17% mean decrease (p less than 0.025) in the corrected peak serum concentration of Ro 10-1670 in all 10 patients after administration of etretinate with milk compared to water. The net result of these alterations is that the mean corrected serum concentration of etretinate is higher than Ro 10-1670 at all time points measured after milk administration. In contrast, after administration of etretinate with water the major retinoid in the serum is Ro 10-1670. Establishing the clinical significance of these alterations may require controlled clinical trials.

Acitretin↗
PubMed1982

Liquid-chromatographic assay for retinol (vitamin A) and retinol analogs in therapeutic trials.

A "high-performance" liquid-chromatographic separation of retinoids (retinol, isotretinoin, all-trans retinoic acid, retinal, etretinate, and retinyl acetate) in serum is described. The separation was used in developing a quantitative assay for retinol (vitamin A) and two therapeutic analogs, isotretinoin (13-cis-retinoic acid) and etretinate (Ro 10-9359). The procedure requires 1 mL of serum. Overall analytical recovery for retinol, isotretinoin, and etretinate from serum was 100% (SD 7%). The between-day coefficient of variation for specimens with concentrations ranging from 0.70 to 0.95 mg/L was less than 4%. Normal reference intervals for serum retinol in men and women are 0.61 to 1.33 and 0.44 to 1.19 mg/L, respectively.

Chromatography, High Pressure Liquid↗
PubMed1980

Comparison of four electrolyte instruments using the proposed NCCLS protocol for evaluation of precision and accuracy of automated instruments.

We compared four instruments, [Sequential Multiple Analyzer Computer (SMAC), AutoAnalyzer II (AAII), StatLyte and PVA-4] for the determination of Na, K, Cl and CO2 using the National Committee for Clinical Laboratory Standard's (NCCLS) protocol (PSEP-1) for evaluation of precision and accuracy of automated instruments. The protocol was applied concurrently to all four instruments. The repeatability results showed SMAC to have the highest precision among-days for K, Cl, and CO2 whereas StatLyte showed the highest precision among-days for Na. The PVA-4 had the best within-run precision for Na and Cl while the AAII and SMAC had the best within-run precision for K and CO2 respectively. Systematic biases among the instruments were small for Na and K. The AAII exhibited a nearly constant bias at all concentrations of Cl relative to the other three instruments. For CO2 the SMAC showed a large proportional bias compared with the other three instruments.

Autoanalysis↗
PubMed1977

Automated computer analysis for enzyme-multiplied immunological techniques.

The dose/response curve in enzyme-multiplied immunoassays (EMIT) and related techniques may be described by the same "four-parameter logistic function" as has proven useful in radioimmunoassays, immunoradiometric assays (IRMA), and two-site immunoradiometric ("sandwhich") assays. This function provides an empirical description of the dose/response curve by use of an objective least-squares regression analysis, with the advantages of computerization and automation. This facilitates further statistical analyses, quality control, estimation of precision for an unknown, and improved, objective estimation of the sensitivity or minimal detectable dose.

Computers↗
PubMed1977

Anticonvulsants in serum, determined with a fully mechanized enzyme analyzer.

The "EMIT" enzyme immunoassay system (Syva) that involves use of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) as the enzyme label has been adapted to a fully mechanized kinetic enzyme analyzer for analysis of phenobarbital, phenytoin, and primidone. This procedure, compared with the gas-chromatographic procedure of Kupferberg [Clin. Chim. Acta 29, 283 (1970)], gave a weighted regression line--forced through the origin--of y=(1.01+/-0.04) x for phenobarbital, y=(0.95+/-0.04) x for primidone. Within-run coefficients of variation based on single determinations were 9,11, and 22% for primidone, phenobarbital, and phenytoin, respectively. Run-to-run assay CV was 6% for primidone and phenobarbital and 13% for phenytoin, based on the means of triplicate determinations of a sample with a mid-range concentration.

Evaluation Studies as Topic↗