Search results for "chromatography"

The effect of olive oil polyphenols on antibodies against oxidized LDL. A randomized clinical trial

2010

summary Background & aim: Oxidized LDL (oxLDL) is a highly immunogenic particle that plays a key role in the development of atherosclerosis. Some data suggest a protective role of OxLDL autoantibodies (OLAB) in atherosclerosis. Our aim was to assess the effect of olive oil polyphenols on the immunogenicity of oxLDL to autoantibody generation. Methods: In a crossover, controlled trial, 200 healthy men were randomly assigned to 3-week sequences of 25 mL/day of 3 olive oils with high (366 mg/kg), medium (164 mg/kg), and low (2.7 mg/kg) phenolic content. Results: Plasma OLAB concentration was inversely associated with oxLDL (p < 0.001). Olive oil phenolic content increased OLAB generation, with…

Circulating 25-Hydroxyvitamin D3 in Pregnancy and Infant Neuropsychological Development

2012

OBJECTIVE:To investigate whether circulating 25-hydroxyvitamin D3 [25(OH)D3] concentration in pregnancy is associated with neuropsychological development in infants.METHODS:The Spanish population-based cohort study INfancia y Medio Ambiente Project recruited pregnant women during the first trimester of pregnancy between November 2003 and February 2008. Completed data on 1820 mother-infant pairs were used. Maternal plasma 25(OH)D3 concentration was measured by high-performance liquid chromatography in pregnancy (mean 13.5±2.1 weeks of gestation). Offspring mental and psychomotor scores were assessed by trained psychologists at age 14 months (range, 11–23) by using the Bayley Scales of Infant…

Immunonephelometric determination of the C4b-binding protein.

1993

A fully mechanised immunonephelometric method for the rapid and specific determination of C4b-binding protein (C4b-BP) in citrated plasma is described. The method utilizes commercially available rabbit antiserum against human C4b-BP and a nephelometer analyser. A single determination can be performed within 6 min, requiring 80 microliters sample volume. The measuring range is about 10 to 200% of normal C4b-BP. Precision is characterized by intraassay coefficients of variation between 1.5% and 2.8%, and interassay coefficients of variation between 4.0% and 4.6% for the same C4b-BP concentrations. The nephelometry of C4b-BP was correlated with electroimmunodiffusion (Laurell technique; r = 0.…

IVIVC for fenofibrate immediate release tablets using solubility and permeability as in vitro predictors for pharmacokinetics.

2010

The goal of this study was to investigate the in vitro-in vivo correlation (IVIVC) for fenofibrate immediate release (IR) tablet formulations based on MeltDose-technique. The in vitro determined drug solubility and permeability data were related to the C(max) values observed from two in vivo human studies. Solubility and permeation studies of fenofibrate were conducted in medium simulating the fasted state conditions in the upper jejunum, containing the surfactant compositions of the six formulations at different concentrations. The behavior of all surfactant compositions was characterized by surface tension, dynamic light scattering, and cryo-TEM. The obtained solubility and permeation dat…

Lorcainide; II. Plasma concentration-effect relationship

1979

Volatile organic compounds (VOCs) in exhaled breath as a marker of hypoxia in multiple chemical sensitivity

2021

Abstract In the history of diagnostics, breath analysis was one of the first method used until the breakthrough of biochemical testing technology. Today, breath analysis has made a comeback with the development of gas analyzers and e‐noses, demonstrating its power in its applicability for diagnosing a wide range of diseases. The physical basis of multiple chemical sensitivity (MCS), an emerging environmental disease, is difficult to understand because it is based on the scenario of chronic hypoxia, with a complex of chemical compounds that trigger the syndrome and result in multiple symptoms. The aim of this study was to investigate MCS by analyzing exhaled volatile organic compounds (VOCs)…

Automated Determination of Fluvoxamine in Plasma by Column-Switching High-Performance Liquid Chromatography

1992

Abstract A column-switching system with high-performance liquid-chromatographic separation and ultraviolet detection is described for automated determination of fluvoxamine in human plasma or serum. Samples were injected and the drug was retained in a clean-up column [20 x 4.6 mm (i.d.)] filled with C8 reversed-phase material (10-micron particles). After unwanted material was washed out, the drug was eluted and separated with an analytical chromatography column, 4.6 x 250 mm (i.d.), filled with Nucleosil 100 CN (5-micron particles) with an acetonitrile:methanol:0.01 mol/L phosphate buffer eluent (188:578:235 by vol) at a flow rate of 1.5 mL/min for &amp;lt; 20 min and detected by spectromet…

Automated Determination of Dextromethorphan and Its Main Metabolites in Human Plasma by High-Performance Liquid Chromatography and Column Switching

1996

An automated column-switching technique coupled to isocratic high-performance liquid chromatography (HPLC) with fluorescence detection was developed for simultaneous determination of dextromethorphan and its three major metabolites, dextrorphan, hydroxymorphinan, and methoxymorphinan. After cleavage of conjugates by incubation with glucuronidasearylsulfatase at 37 degrees C for 15 h, plasma samples were injected directly into the HPLC system. Dextromethorphan and metabolites were retained on a cleanup column (10 x 4.6 mm internal diameter [ID]) filled with cyanopropyl (CN) material (Hypersil CPS, 10-microns article size) while interfering proteins and lipids were washed to waste. After colu…

Detection of gamma-hydroxybutyrate in hair: Validation of GC–MS and LC–MS/MS methods and application to a real case

2012

A gas chromatography-mass spectrometry (GC-MS) and a liquid chromatography tandem mass spectrometry (LC-MS/MS) method were validated for quantifying endogenous and exogenous hair concentrations of gamma-hydroxybutyrate (GHB). The GC-MS method is based on overnight extraction of 25 mg hair in NaOH at 56 °C, liquid/liquid extraction in ethylacetate and trimethylsylil derivatization; analysis is by electron ionization and single ion monitoring of three ions. The LC-MS/MS method entails a rapid digestion of 25 mg hair with NaOH at 75 °C for 40 min, liquid/liquid extraction in ethylacetate and reconstitution of the extract in the LC mobile phase; negative ion electrospray ionization and multiple…

Variability of human saliva composition: possible relationships with fat perception and liking

2012

International audience; Saliva is the medium that bathes the taste receptors in the oral cavity and in which aroma and taste compounds are released when food is eaten. Moreover saliva contains enzymes and molecules that can interact with food. To date, little research has been devoted to the intra- and inter-individual variabilities of these components and their inter-relationships. The first aim of this work was to study intra- and inter-individual variabilities over time in the composition of molecules likely to interact with food in the mouth, with particular focus on molecules that might interact with fat. The second aim was to try to relate this composition to a liking for fat and its …