Homicidal poisoning series in a nursing home: retrospective toxicological investigations in bone marrow and hair.

Homicidal poisonings remain rare and can be difficult to detect, especially in the elderly or in medical settings. In this atypical poisoning series, a young nursing assistant purposely poisoned thirteen residents of a nursing home and killed ten of them. The medications used were a mix of psychotropic medications (cyamemazine, loxapine, tiapride, risperidone, and mirtazapine), under liquid formulation, which were inducing malaise and coma. The forensic investigation included analysis of blood, urine, hair, and bone marrow and exhumations of seven corpses up to 3 years after the inhumation. Hair collected from a hairbrush of a cremated victim have been analyzed. Bone marrow sample preparation was based on a liquid/liquid triple extraction. Hair were incubated after decontamination overnight at 55 °C in methanol. Segmentation was possible for seven samples, except for delayed exhumation samples (n = 4) and hairbrush hair sample (n = 1). The extracts were then analyzed using gas chromatography coupled with mass spectrometry (GC-MS) for unknown screening and using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for a targeted screening and quantification. Screenings revealed the presence of the same mix of psychotropic medications. Cyamemazine, mirtazapine, loxapine, tiapride, and risperidone hair concentrations were 6-17,458 pg/mg, 74-1271 pg/mg, 9-1346 pg/mg, 13-148 pg/mg, and 3-5 pg/mg, respectively. Cyamemazine bone marrow concentrations were 229 and 681 ng/g and 152-717 ng/mL in blood. Patients' medications were also identified and quantified. This poisoning series provide analytical data that could support subsequent toxicological result interpretation in similar forensic cases.

[Accreditation of the toxicological screening: recommendations of the SFBC-SFTA group]. / Accréditation du criblage toxicologique : recommandations du groupe SFBC-SFTA.

Toxicological screening is a specific approach to analytical toxicology that uses analytical tools such as GC-MS, LC-UV (diode array) or LC-MS. Toxicological screening allows the detection and simultaneous identification of a large number of compounds. The results may be based on the use of one or more techniques. As part of the accreditation process for medical biology examinations according to standard NF EN ISO 15189, the group from SFTA and SFBC recommends an approach to accredit toxicological screening. Indeed, the complexity of the accreditation of this analysis comes in particular from the high number of compounds that can be detected. Validation parameters are discussed in the specific context of toxicological screening by considering two distinct approaches: the simple identification of compounds, or the identification and estimation of a range of concentration related to clinical outcomes.

Specific Conditions for Resveratrol Neuroprotection against Ethanol-Induced Toxicity.

Aims. 3,5,4'-Trihydroxy-trans-stilbene, a natural polyphenolic compound present in wine and grapes and better known as resveratrol, has free radical scavenging properties and is a potent protector against oxidative stress induced by alcohol metabolism. Today, the mechanism by which ethanol exerts its toxicity is still not well understood, but it is generally considered that free radical generation plays an important role in the appearance of structural and functional alterations in cells. The aim of this study was to evaluate the protective action of resveratrol against ethanol-induced brain cell injury. Methods. Primary cultures of rat astrocytes were exposed to ethanol, with or without a pretreatment with resveratrol. We examined the dose-dependent effects of this resveratrol pretreatment on cytotoxicity and genotoxicity induced by ethanol. Cytotoxicity was assessed using the MTT reduction test. Genotoxicity was evidenced using single cell gel electrophoresis. In addition, DNA staining with fluorescent dyes allowed visualization of nuclear damage using confocal microscopy. Results. Cell pretreatment with low concentrations of trans-resveratrol (0.1-10 µM) slowed down cell death and DNA damage induced by ethanol exposure, while higher concentrations (50-100 µM) enhanced these same effects. No protection by cis-resveratrol was observed. Conclusion. Protection offered by trans-resveratrol against ethanol-induced neurotoxicity was only effective for low concentrations of this polyphenol.

Influence of vitamin E, sodium selenite, and astrocyte-conditioned medium on neuronal survival after chronic exposure to ethanol.

Free radicals species generation during ethanol metabolism is implicated in ethanol-induced toxicity. Findings from clinical studies have clearly established the association between alcohol intake and nutritional deficiency. Astrocytes are able to promote neuronal survival against different lethal injuries involved in ethanol-induced toxicity. We therefore studied the ability of hydrosoluble vitamin E (trolox), sodium selenite, and astrocyte-conditioned medium to protect cultured rat neurones against ethanol-induced oxidative stress after chronic exposure to ethanol. When a 6-day exposure to ethanol (20 mM) led to a loss of cell viability, the presence of trolox (10 microM) offered a significant neuroprotection. In the presence of 3-amino-1,2,4-triazole, a catalase inhibitor that created conditions that were favorable to reactive oxygen species accumulation, trolox was able to counteract the deleterious effect of the inhibitor. Moreover, flow cytometric analysis indicated that trolox can maintain the intracellular glutathione content in neurones chronically exposed to ethanol. In these conditions of exposure, the absence of sodium selenite in the culture medium significantly aggravated the exposure-induced effects, whereas sodium selenite (100 nM) offered a significant neuroprotection. Finally, the presence of 25% astrocyte-conditioned medium in the neuronal culture medium induced a neuroprotective effect in the presence of ethanol. Nevertheless, when astrocytes were previously chronically (3 days) exposed to ethanol, their culture medium did not offer a significant protection. These results evidenced that vitamin E and astrocytes can protect neurones from ethanol-induced oxidative stress, notably by contributing to maintaining the intracellular glutathione levels. Selenium, by means of its exogenous addition in the form of sodium selenite, also had an interesting neuroprotective effect.