PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 8205244

Novel high-performance liquid chromatographic method using solid-phase on-line elution for determination of metolazone in plasma and whole blood.

D Farthing·D A Sica·I Fakhry·T W Gehr
View original source ↗Export metadata ↓

Abstract

A novel solid-phase on-line elution HPLC method employing fluorescence detection to measure metolazone in plasma and whole blood has been developed. The method is sensitive and selective for metolazone and linear over a dynamic range of 1-50 ng/ml with a sample requirement of 250 microliters. The limit of quantitation for the method is 1 ng/ml and combined intra- and inter-day accuracy and precision had an error and coefficient of variation of 2.9 and 5.5%, respectively.

Explore related subjects

Chromatography, High Pressure LiquidHumansKidney Failure, ChronicMaleMetolazoneReproducibility of ResultsSensitivity and SpecificitySpectrometry, FluorescenceJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D Farthing, D A Sica, I Fakhry, T W Gehr. 1994-03-04. Novel high-performance liquid chromatographic method using solid-phase on-line elution for determination of metolazone in plasma and whole blood.. https://doi.org/10.1016/0378-4347(93)e0427-r

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1996

Oxidative damage to DNA constituents by iron-mediated fenton reactions. The deoxycytidine family.

Damage by iron-mediated Fenton reactions under aerobic or anaerobic conditions to deoxycytidine, deoxycytidine-5'-monophosphate, d-CpC, d-CpCpC, and dCMP residues in DNA resulted in at least 26 distinguishable products. Of these, 24 were identified by high performance liquid chromatography retention times, radiolabeling, UV absorption spectra, chemical synthesis, fast atom bombardment mass spectrometry, high resolution fast atom bombardment mass spectrometry, and/or NMR. The nature of the products was qualitatively similar for each substrate except for d-CpC (and possibly d-CpCpC) under anaerobic conditions for which 5-hydroxy-deoxycytidine was uniquely present and 1-carbamoyl-1-carboxy-4-(2-deoxy-beta-D-erythropentofuranosyl) glycinamide was uniquely absent. Damage to dC, d-CpC, and d-CpCpC but not to dCMP or DNA was largely quenched by ethanol, indicating that iron is strongly associated only with dCMP and DNA. The presence of oxygen had little effect with dC or dCMP but had quantitative and qualitative effects with d-CpC and a significantly quantitative but not a qualitative effect with DNA. NADH could drive the Fenton reaction to cause damage to the dC family in vitro, consistent with a previous proposal that NADH was the reducing agent for the Fenton reaction in vivo (Imlay, J.A., and Linn, S. (1988) Science 240, 1302-1309). Finally, the damage spectrum of the dC family by the Fenton reaction is compared with that by ionizing radiation and chemical mechanisms leading to the formation of the 24 identified products are proposed.

Chromatography, High Pressure Liquid↗
PubMed1996

Oxidative damage to DNA constituents by iron-mediated fenton reactions. The deoxyguanosine family.

2'-Deoxyguanosine, 3'-dGMP, 5'-dGMP, d-GpG, or double-stranded DNA were exposed to H2O2 in the presence of Fe2+ under anaerobic conditions or under aerobic conditions in the presence of Fe3+, Fe2+, Fe2+/NADH, or Fe3+/NADH with and without ethanol. The products were enzymatically digested to nucleosides, separated by high performance liquid chromatography (HPLC), quantified, and characterized by HPLC retention time, radiolabeling, UV absorbance spectrometry, NMR, and mass spectrometry. 20 products, constituting 78-81% of the damage, were distinguished from aerobic reactions of Fe2+/H2O2 with dG and dGMP, 16 of which were identified. The product spectra from dG, 3'-dGMP, and 5'-dGMP differ from one another, and the spectrum of the 5' nucleoside of d-GpG differs from that of the 3' nucleoside. 7, 8-Dihydro-8-oxo-2'-deoxyguanosine is the most abundant DNA-bound product aside from abasic sites, and its formation was more closely analyzed. Both NADH, which can reduce Fe3+, and ethanol, which can scavenge some free radicals, change the product profiles. Damage enhancement by NADH follows the sequence dG < d-GpG < 3'-dGMP < 5'-dGMP < DNA; the reverse sequence is observed for ethanol quenching. This sequence of susceptibility and the product differences seen for the 3' and 5' phosphate may reflect localization of iron and the damaging radicals upon the substrate.

Chromatography, High Pressure Liquid↗
PubMed1996

Characterization of the denaturation and renaturation of human plasma vitronectin. I. Biophysical characterization of protein unfolding and multimerization.

Upon treatment with denaturing agents, vitronectin has been observed to exhibit conformational alterations which are similar to the structural changes detected when vitronectin binds the thrombin-antithrombin complex or associates with the terminal attack complex of complement. Denaturation and renaturation of vitronectin isolated from human plasma were characterized by changes in intrinsic fluorescence. Unfolding by chemical denaturants was irreversible and accompanied by self-association of the protein to form vitronectin multimers. Self-association was evaluated by equilibrium analytical ultracentrifugation which demonstrated that multimers form only during the refolding process after removal of denaturant, that multimeric vitronectin dissociates to constituent subunits readily upon treatment with chemical denaturant, and that intermolecular disulfide cross-linking occurs primarily at the dimer level among a subset of constituent vitronectin subunits within the multimer. The monomeric form of vitronectin isolated from human plasma partially unfolds at intermediate concentrations of denaturant to an altered conformation with a high propensity to associate into multimers. Folding of vitronectin in vivo appears to be regulated by partitioning of folding intermediates toward either of two conformations, one that exists as a stable monomer and another that associates into a multimeric form.

Chromatography, High Pressure Liquid↗