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Biomedical subjects

C M Riley

Publications and source records attributed to C M Riley.

87 records · Page 5Linked to original sources
PubMed1982

High-performance liquid chromatography of platinum complexes on solvent generated anion exchangers. III. Application to the analysis of cisplatin in urine using automated column switching.

Platinum complexes are retained on solvent generated anion exchangers, prepared by coating reversed-phase (C-18) supports with a monolayer of hexadecyltrimethylammonium bromide. The retention mechanism is described in terms of ion--dipole interactions in the stationary phase, reinforced by a hydrophobic effect. The high degree of ligand selectivity exhibited by these systems arises from the use of purely aqueous mobile phases which maximize the differences in solute dipole and hydrophobic surface area. By using stationary phases of different surface characteristics and the application of automated column switching, the technique is applicable to the clinical analysis of cisplatin in urine. After chromatography, the purified cisplatin fractions area determined by atomic absorption spectrophotometry. The recovery of cisplatin from urine is 101.1% with a relative standard deviation of 3.6% and the limit of detection is 2 micrograms/ml.

Automation↗
PubMed1979

Ion-pair high-performance liquid chromatography: the use of low concentrations of long-chain alkylbenzyldimethylammonium chlorides for resolving anionic solutes.

The qualitative and quantitative determination of large anionic solutes, including the drug sodium cromoglycate, by an ion-pair high-performance liquid chromatographic technique using alkylbenzyldimethylammonium chlorides as pairing ions is described. The method provides a sensitive and selective assay for the solutes examined in both simple aqueous solutions and in complex biological fluids, and requires no pre-extraction step. Retention mechanisms are discussed.

Anions↗
PubMed1979

Surfactant ion-pair high-performance liquid chromatography of tryptophan and some of its metabolites in biological fluids.

A rapid, sensitive assay for tryptophan and some of its metabolites in urine, plasma and saliva has been developed using sodium dodecylsulphate as a pairing ion in a surfactant ion-pair high-performance liquid chromatography technique. The method is highly selective for tryptophan which is separated from its main indoleamine metabolites, 5-hydroxytryptophan, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid, and from kynurenine. The usefulness of the assay has been demonstrated in plasma level and urinary excretion studies of orally administered tryptophan.

Biological Availability↗
PubMed1978

Recruitment and retention program for minority and disadvantaged students.

Attracting ethnic minority and disadvantaged students to health careers and facilitating their successful completion of training program requirements have been major activities of the University of Colorado Medical Center since 1969. As a result of extensive college campus recruitment efforts, high school and college level preprofessional programs, and the participation of ethnic minority faculty members in the medical school admissions process, the number of applicants to the medical school increased from 45 in 1971 to 265 in 1977. Concurrently, medical school matriculants increased from 12 in 1971 to 24 in 1977, with a maximum of 30 in 1975. However, significantly fewer minority students have shown interest in nursing, dentistry, or allied health professions careers. Because of support programs for matriculants (including preadmission and postadmissions personal, academic, study skills, and test-taking counseling and a prefreshman year summer orientation course), 71 percent of the minority students entering medical school in 1971-73 have received the M.D. degree.

Colorado↗
PubMedDate not supplied

Reversed-phase liquid chromatography of the opioid peptides. 3. Development of a microanalytical system for opioid peptides involving microbore liquid chromatography, post-column derivatization and laser-induced fluorescence detection.

A microanalytical system has been developed for the determination of peptides in small samples. Naphthalene-2,3-dicarboxaldehyde-beta-mercaptoethanol (NDA-BME) was used as the labelling reagent system as an alternative to NDA-cyanide (NDA-CN) because of the faster labelling when CN was replaced by a thiol. The fluorescence characteristics of the NDA-thiol adducts, N-substituted 1-alkylthiobenz[f]isoindoles (TBIs), were found to be different from the previously described cyanobenz[f]isoindole (CBIs) adducts formed by the reaction of primary amines with NDA-CN. The excitation maximum of the TBI adducts was at 460 nm, which was closer to the 457.9 nm argon-ion laser line, than the 440-nm maximum of the CBI adduct. The limit of detection for leucine enkephalin was 36 fmol (S/N = 3) and linearity was proven for greater than 2 orders of magnitude, from 45 fmol to 9 pmol for an injection volume of 60 nl. The detectability was limited by the high background noise produced by the post-column derivatization system. The utility of the system was demonstrated for the analysis of methionine enkephalin and its potential oxidation products, using leucine enkephalin as a suitable internal standard.

Chromatography, Liquid↗