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Your search keyword '"Rivier, L."' showing total 4 results
Start Over Author "Rivier, L." Topic gas chromatography-mass spectrometry
4 results on '"Rivier, L."'

1. Comparison of different immunoassays and GC-MS screening of benzodiazepines in urine.

Author

Augsburger M, Rivier L, and Mangin P

Subjects
Humans, Lorazepam analogs & derivatives, Lorazepam urine, Reproducibility of Results, Sensitivity and Specificity, Anti-Anxiety Agents urine, Benzodiazepines urine, Gas Chromatography-Mass Spectrometry methods, Immunoassay methods
Abstract

A total of 53 urine samples were tested by different immunoassay methods and by gas chromatography/mass spectrometry to determine repeatability of the different methods and to assess whether the immunoassays performed on samples obtained from elderly patients of the emergency section could be considered as reliable enough for identifying a benzodiazepine consumption. Repeatability was excellent for GC/MS and good for immunoassays. The specificity was not different for the three immunoassays (96%). The sensitivity varied from 36, 64 to 75% for OnLine, RIA Immunalysis and RIA DPC, respectively. An other difference between immunoassays and GC/MS was the ability of GC/MS to detect lorazepam and low concentrations of benzodiazepines whereas immunoassays did not.

Published
1998
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2. Rapid high-performance liquid chromatographic determination with fluorescence detection of furosemide in human body fluids and its confirmation by gas chromatography-mass spectrometry.

Author

Saugy M, Meuwly P, Munafo A, and Rivier L

Subjects
Administration, Oral, Fluorescence, Furosemide administration & dosage, Furosemide urine, Humans, Male, Substance Abuse Detection, Time Factors, Chromatography, High Pressure Liquid methods, Furosemide blood, Gas Chromatography-Mass Spectrometry methods
Abstract

Furosemide (FD: Lasix) is a loop diuretic which strongly increases both urine flow and electrolyte urinary excretion. Healthy volunteers were administered 40 mg orally (dissolved in water) and concentrations of FD were determined in serum and urine for up to 6 h for eight subjects, who absorbed water at a rate of 400 ml/h. Quantification was performed by HPLC with fluorescence detection (excitation at 233 nm, emission at 389 nm) with a limit of detection of 5 ng/ml for a 300-microliters sample. The elution of FD was completed within 4 min using a gradient of acetonitrile concentration rising from 30 to 50% in 0.08 M phosphoric acid. The delay to the peak serum concentration ranged from 60 to 120 min. FD was still easily measurable in the sera from all subjects 6 h after administration. In urine, the excretion rates reached their maximum between 1 and 3 h. The total amount of FD excreted in the urine averaged 11.2 mg (range 7.6-14.0 mg), with a mean urine volume of 3024 ml (range 2620-3596 ml). Moreover, the urine density was lower than 1.010 (recommended as an upper limit in doping analysis to screen diuretics) only for 2 h. An additional volunteer was administered 40 mg of FD and his urine was collected over a longer period. FD was still detectable 48 h after intake. Gas chromatography-mass spectrometry with different types of ionization was used to confirm the occurrence of FD after permethylation of the extract. Negative-ion chemical ionization, with ammonia as reactant gas, was found to be the most sensitive method of detection.

Published
1991
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4. Ecstasy--the status in French-speaking Switzerland. Composition of seized drugs, analysis of biological specimens and short review of its pharmacological action and toxicity

Author

Giroud C, Marc Augsburger, Sadeghipour F, Varesio E, Jl, Veuthey, and Rivier L

Subjects
ddc:615, Substance-Related Disorders, N-Methyl-3,4-methylenedioxyamphetamine, Substance-Related Disorders/blood/epidemiology, Gas Chromatography-Mass Spectrometry, Hallucinogens/analysis/chemistry/pharmacokinetics/pharmacology, Switzerland/epidemiology, mental disorders, Hallucinogens, Humans, N-Methyl-3,4-methylenedioxyamphetamine/analysis/chemistry/pharmacokinetics/pharmacology, Switzerland, psychological phenomena and processes, Chromatography, High Pressure Liquid
Abstract

Methylenedioxy-N-methylamphetamine (MDMA, "Ecstasy") and other related phenylethylamines are nowadays used extensively in Western Switzerland at dance clubs and raves. There is a widely held belief among teenagers and misusers that ecstasy is safe. In the last years however, an increasing number of reports of MDMA-related deaths has been reported. Acute clinical toxicity problems following MDMA ingestion include hyperthermia, convulsions and arrhythmias. There is also growing concern that these phenylethylamines are neurotoxic and cause long-term damage to serotonineric nerve terminals in animal brains. Qualitative analyses by GC-MS of street samples of ecstasy showed that only a part of them contain MDMA or related phenylethylamines (MDA, MDEA, MBDB and 2C-B). Most of them were mixed with caffeine and an excipient (sugars or polyols [e.g. mannitol]). Amphetamine cut with caffeine and other drugs (e.g. testosterone), stimulants (e.g. pseudoephedrine) and other drugs unrelated to stimulants and phenylethylamines (e.g. LSD, chloroquine, vasodilators) were also detected. Quantitative determinations performed by HPLC-DAD or EC-DAD reveal huge fluctuations in the amount of active substance(s) per tablet. MDMA and related compounds display unique psychoactive properties, acting as a stimulant and inducing feelings of empathy. The effects of MDMA intake are very likely the results of the large release of serotonin (5-HT) in the synaptic cleft, of the inhibition of the re-uptake inactivation of 5-HT and of the inhibition of a key-enzyme involved in the biosynthesis of 5-HT. Forensic investigations performed at our institute showed significant blood levels of MDMA, MDEA and MDA in samples drawn from people suspected of driving under the influence of psychoactive drugs. Up to now, no death could be attributed to MDMA intoxication only because our analyses always revealed the additional presence of toxic amounts of other psychoactive drugs (e.g. opiates, cocaine). Our study shows that because of the variable composition of ecstasy tablets, unpredictable types and amounts of drugs may be taken by MDMA misusers. Moreover, there is considerable concern that traffic accidents may be caused by MDMA-abusers. MDMA intake could result in severe intoxication and even death, especially when combined with other types of drugs.

Published
1997

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