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Dive into the research topics where Nele Samyn is active.

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Featured researches published by Nele Samyn.


Forensic Science International | 2002

Plasma, oral fluid and sweat wipe ecstasy concentrations in controlled and real life conditions

Nele Samyn; Gert De Boeck; Michelle Wood; Caroline T. J. Lamers; Dick de Waard; Karel Brookhuis; Alain Verstraete; Wim J. Riedel

In a double-blind placebo controlled study on psychomotor skills important for car driving (Study 1), a 75 mg dose of +/- 3,4-methylenedioxymethamphetamine (MDMA) was administered orally to 12 healthy volunteers who were known to be recreational MDMA-users. Toxicokinetic data were gathered by analysis of blood, urine, oral fluid and sweat wipes collected during the first 5h after administration. Resultant plasma concentrations varied from 21 to 295 ng/ml, with an average peak concentration of 178 ng/ml observed between 2 and 4h after administration. MDA concentrations never exceeded 20 ng/ml. Corresponding MDMA concentrations in oral fluid, as measured with a specific LC-MS/MS method (which required only 50 microl of oral fluid), generally exceeded those in plasma and peaked at an average concentration of 1215 ng/ml. A substantial intra- and inter-subject variability was observed with this matrix, and values ranged from 50 to 6982 ng/ml MDMA. Somewhat surprisingly, even 4-5h after ingestion, the MDMA levels in sweat only averaged 25 ng/wipe. In addition to this controlled study, data were collected from 19 MDMA-users who participated in a driving simulator study (Study 2), comparing sober non-drug conditions with MDMA-only and multiple drug use conditions. In this particular study, urine samples were used for general drug screening and oral fluid was collected as an alternative to blood sampling. Analysis of oral fluid samples by LC-MS/MS revealed an average MDMA/MDEA concentration of 1121 ng/ml in the MDMA-only condition, with large inter-subject variability. This was also the case in the multiple drug condition, where generally, significantly higher concentrations of MDMA, MDEA and/or amphetamine were detected in the oral fluid samples. Urine screening revealed the presence of combinations such as MDMA, MDEA, amph, cannabis, cocaine, LSD and psilocine in the multiple-drug condition.


Psychopharmacology | 2004

Effects of MDMA (ecstasy), and multiple drugs use on (simulated) driving performance and traffic safety

Karel Brookhuis; Dick de Waard; Nele Samyn

RationaleThe effects of MDMA on driving behaviour are not clear, since the direct effects of MDMA on cognitive performance are reported as not generally negative.ObjectivesTo assess in an advanced driving simulator acute effects on simulated driving behaviour and heart rate of MDMA, and effects of polydrug use.MethodsA group of young participants who had indicated that they regularly used MDMA were asked to complete test rides in an advanced driving simulator, shortly after the use of MDMA, just before going to a party. They were tested again after having visited the “rave”, while they were under the influence of MDMA and a number of different other active drugs. Participants were also tested sober, at a comparable time at night. Separately, a control group of participants was included in the experiment.ResultsDriving performance in the sense of lateral and longitudinal vehicle control was not greatly affected after MDMA, but deteriorated after multiple drug use. The most striking result was the apparent decreased sense for risk taking, both after MDMA and after multiple drug use. This was clear from gap acceptance data, while the ultimate indicator of unsafe driving, accident involvement or even causation, was increased by 100% and 150%, respectively.ConclusionsDriving under the influence of MDMA alone is certainly not safe; however, driving back (home) after a dance party (“rave”) where MDMA users regularly combine MDMA with a host of other drugs can be described as extremely dangerous.


Journal of Chromatography B: Biomedical Sciences and Applications | 1999

Determination of “Ecstasy” components in alternative biological specimens

Pascal Kintz; Nele Samyn

This paper reviews procedures for the determination of methylenedioxyamphetamine derivatives, MDA, MDMA, MDEA and MBDB in saliva, sweat and hair. For this topic, the international literature appears very poor, particularly for saliva and sweat. MDMA was first reported in hair in 1993. All but one of the reviewed papers reported detection with GC-MS. No references seem to be available for both meconium and vitreous humor. As it has been already reported in these biological specimens, the parent drug is detected in higher concentrations than its metabolites. The main data on sample preparation, work-up, GC column, derivatization and analytical determination are listed. Several references, taken from the forensic practice are used to document the cases. Some new findings, based on the experience of the author, are also added. Some references, dealing with amphetamine and methamphetamine in alternative specimens are listed in the manuscript to give an overview on the stimulants detection.


Journal of Analytical Toxicology | 2005

Validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of 26 benzodiazepines and metabolites, zolpidem and zopiclone, in blood, urine, and hair.

Marleen Laloup; Maria del Mar Rarnirez Fernandez; Gert De Boeck; Michelle Wood; Viviane Maes; Nele Samyn


Journal of Chromatography A | 2007

High-throughput on-line solid-phase extraction–liquid chromatography–tandem mass spectrometry method for the simultaneous analysis of 14 antidepressants and their metabolites in plasma

Ana de Castro; Maria del Mar Ramirez Fernandez; Marleen Laloup; Nele Samyn; Gert De Boeck; Michelle Wood; Viviane Maes; Manuel López-Rivadulla


Analytical and Bioanalytical Chemistry | 2007

Detection of diazepam in urine, hair and preserved oral fluid samples with LC-MS-MS after single and repeated administration of Myolastan® and Valium®

Marleen Laloup; Maria del Mar Ramirez Fernandez; Michelle Wood; Viviane Maes; Gert De Boeck; Yvan Vanbeckevoort; Nele Samyn


Forensic Science International | 2006

Correlation of Δ9-tetrahydrocannabinol concentrations determined by LC-MS-MS in oral fluid and plasma from impaired drivers and evaluation of the on-site Dräger DrugTest®

Marleen Laloup; Maria del Mar Ramirez Fernandez; Michelle Wood; Gert De Boeck; Viviane Maes; Nele Samyn


Journal of Chromatography A | 2005

Quantitative analysis of Δ9-tetrahydrocannabinol in preserved oral fluid by liquid chromatography-tandem mass spectrometry

Marleen Laloup; Maria del Mar Ramirez Fernandez; Michelle Wood; Gert De Boeck; Cécile Henquet; Viviane Maes; Nele Samyn


Journal of Analytical Toxicology | 2002

Detection of flunitrazepam and 7-aminoflunitrazepam in oral fluid after controlled administration of rohypnol

Nele Samyn; Gert De Boeck; Vincent Cirimele; Alain Verstraete; Pascal Kintz


Journal of Chromatography A | 2004

Simultaneous analysis of gamma-hydroxybutyric acid and its precursors in urine using liquid chromatography-tandem mass spectrometry

Michelle Wood; Marleen Laloup; Nele Samyn; Michael Morris; Ernst A. de Bruijn; R. A. A. Maes; Michael S. Young; Viviane Maes; Gert De Boeck

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Gert De Boeck

The Catholic University of America

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Viviane Maes

Free University of Brussels

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Pierre Wallemacq

Université catholique de Louvain

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Manuel López-Rivadulla

University of Santiago de Compostela

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