Primerjava toksičnosti etanola in acetaldehida za podganje astrocite v primarni kulturi

This study compared the effects of toxicity of ethanol and its first metabolite acetaldehyde in rat astrocytes through cell viability and cell proliferation. The cells were treated with different concentrations of ethanol in the presence or absence of a catalase inhibitor 2-amino-1,2,4 triazole (AMT) or with different concentrations of acetaldehyde. Cell viability was assessed using the trypan blue test. Cell proliferation was assessed after 24 hours and after seven days of exposure to either ethanol or acetaldehyde. We showed that both ethanol and acetaldehyde decreased cell viability in a dose-dependent manner. In proliferation studies, after seven days of exposure to either ethanol or acetaldehyde, we observed a significant dose-dependent decrease in cell number. The protein content study showed biphasic dose-response curves, after 24 hours and seven days of exposure to either ethanol or acetaldehyde. Co-incubation in the presence of AMT significantly reduced the inhibitory effect of ethanol on cell proliferation. We concluded that long-term exposure of astrocytes to ethanol is more toxic than acute exposure. Acetaldehyde is a much more potent toxin than ethanol, and at least a part of ethanol toxicity is due to ethanol’s first metabolite acetaldehyde.V študiji smo primerjali toksičnost etanola in njegovega prvega metabolita acetaldehida za podganje astrocite z določitvijo celične viabilnosti in proliferacije. Celične kulture smo tretirali z različnimi koncentracijami etanola, etanola v prisotnosti inhibitorja katalaze 2-amino-1,2,4 triazol-a (AMT) ali z različnimi koncentracijami acetaldehida. Celično viabilnost smo vrednotili s pomočjo testa s tripanskim modrilom, celično proliferacijo pa s štetjem celic in določitvijo koncentracije proteinov po 24-urni, kot tudi 7-dnevni izpostavljenosti. S študijo smo pokazali, da tako etanol kot tudi acetaldehid v odvisnosti od njune koncentracije zmanjšata celično viabilnost. V študiji proliferacije sta etanol in acetaldehid, v odvisnosti od njunih koncentracij, značilno zmanjšala število celic po 7-dnevni izpostavljenosti. Pri ugotavljanju vsebnosti proteinov smo dobili bifazno krivuljo tako po 24-urni, kot tudi po 7-dnevni izpostavljenosti različnim koncentracijam etanola oziroma acetaldehida. Prisotnost AMT je signifi kantno zmanjšala učinek etanola na celično proliferacijo. Zaključimo lahko, da je dolgotrajna izpostavljenost astrocitov etanolu bolj toksična kot akutna. Acetaldehid je močnejši toksin kot etanol in vsaj del toksičnosti etanola je posledica delovanja njegovega prvega metabolita, acetaldehida

Post-column hydrogen-deuterium exchange technique to assist in the identification of small organic molecules by mass spectrometry

In order to improve the certainty that a specific small organic molecule has been detected in a given sample by high-resolution mass spectrometry, other techniques that give conclusive evidence about the chemical structure of a compound like nuclear magnetic resonance (NMR) or complementary information on its composition such as hydrogen-deuterium exchange (HDX) are often necessary. This study presents a systematic investigation that aims to improve the applicability of post-column HDX for those purposes. Key parameters like mobile phase flow rates, volume percentage of H2O in the mobile phase and D2O addition flow rates were optimized in order to provide an isotopic pattern that allows the accurate determination of the number of exchangeable hydrogen atoms in small organic molecules. A loop injection setup was used to emulate chromatographic conditions in the optimization process, and trimethoprim, a widely-used anti-infective, was used as test compound for the experiments. As expected, results showed that deuteration percentage decreased with a higher mobile phase flow rate and increased with higher D2O flow rate. The post-column HDX technique was then validated with extracts of samples of river water and plants separated by liquid chromatography in hydrophilic interaction or reversed phase modes. Mass spectra showed a completely visible isotopic pattern that allowed assessing correctly and unambiguously the number of exchangeable hydrogens in the compounds of interest. This study shows that post-column HDX can be used as complementary technique to identify unknown small organic molecules in complex matrices. The current paper proposes an efficient, cost-effective, versatile technique of HDX that is helpful to assign a unique structure to a given high-resolution mass spectrometry signal.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Robotic Observations of the Sky with TAROT: 2004--2007

International audienceThe TAROTs (Télescopes à Action Rapide pour les Objets Transitoires; Rapid Action Telescopes for Transient Objects) are two fully robotic observatories designed to observe the early transient optical counterpart of gamma-ray bursts (GRBs). As their occurrence is rare, we also use TAROT to observe various other celestial objects: RR Lyrae stars, minor planets and supernovae. In this paper, we describe the telescopes, their networking, and the data-processing methods used

Imputabilité en toxicologie postmortem : exemple d'un travail sur la pholcodine

Date du colloque&nbsp;: 10/2008</p

Imputabilité en toxicologie postmortem : exemple d'un travail sur la pholcodine

Date du colloque&nbsp;: 10/2008</p

TAROT: Observing gamma-ray bursts "in progress”

The primary objective of the Télescope à Action Rapide pour les Objets Transitoires (TAROT - Rapid Action Telescope for Transient Objects) observatory is the detection of cosmic Gamma-Ray Burst sources at optical wavelengths while still active in Gamma-rays. It features a very rapid slewing mount, a 25 cm aperture telescope with a $2\times 2$ deg. fov, and is able to reach the 17th V magnitude in 10 s. A powerful scheduling algorithm, and an automated data processing system makes TAROT a fully autonomous facility. TAROT entered into service during the fall of 1998

Optimisation de méthodes diélectriques pour l'hydrologie

National audienc