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33 result(s) for "Varlet, Vincent"
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E-Cigarettes: A Review of New Trends in Cannabis Use
The emergence of electronic cigarettes (e-cigs) has given cannabis smokers a new method of inhaling cannabinoids. E-cigs differ from traditional marijuana cigarettes in several respects. First, it is assumed that vaporizing cannabinoids at lower temperatures is safer because it produces smaller amounts of toxic substances than the hot combustion of a marijuana cigarette. Recreational cannabis users can discretely “vape” deodorized cannabis extracts with minimal annoyance to the people around them and less chance of detection. There are nevertheless several drawbacks worth mentioning: although manufacturing commercial (or homemade) cannabinoid-enriched electronic liquids (e-liquids) requires lengthy, complex processing, some are readily on the Internet despite their lack of quality control, expiry date, and conditions of preservation and, above all, any toxicological and clinical assessment. Besides these safety problems, the regulatory situation surrounding e-liquids is often unclear. More simply ground cannabis flowering heads or concentrated, oily THC extracts (such as butane honey oil or BHO) can be vaped in specially designed, pen-sized marijuana vaporizers. Analysis of a commercial e-liquid rich in cannabidiol showed that it contained a smaller dose of active ingredient than advertised; testing our laboratory-made, purified BHO, however, confirmed that it could be vaped in an e-cig to deliver a psychoactive dose of THC. The health consequences specific to vaping these cannabis preparations remain largely unknown and speculative due to the absence of comprehensive, robust scientific studies. The most significant health concerns involve the vaping of cannabinoids by children and teenagers. E-cigs could provide an alternative gateway to cannabis use for young people. Furthermore, vaping cannabinoids could lead to environmental and passive contamination.
What are the limitations of methods to measure carbon monoxide in biological samples?
Purpose Carbon monoxide (CO) is one of the most important toxic gases in the atmosphere. Its high affinity for hemoglobin has made carboxyhemoglobin (COHb) the most appropriate biomarker for CO poisoning. COHb is measured using spectrophotometric (ultraviolet-spectrophotometry, CO-oximetry) or gas chromatographic (GC) methods combined with flame ionization or mass spectrometry (MS) detectors. However, inconsistencies in many cases have been reported between measured values and reported symptoms, raising doubts as to the suitability of COHb as a biomarker and the accuracy and reliability of its measurement methods. Therefore, we aimed to review the accuracy of current methods used to measure CO and to determine their sources of error and their effects on the interpretation process. Methods A detailed search of PubMed was performed in November 2018 using relevant keywords. After exclusion criteria were applied, 46 articles out of 191 initial hits were carefully reviewed. Results While optical methods are highly influenced by changes in blood quality due to degradation of samples during storage, GC methods are less affected. However, measurement of COHb does not quantify free CO, which is mainly responsible for toxicity mechanisms other than hypoxia, such as inhibition of hemoproteins, thus underestimating the true CO burden. Therefore, measurement of COHb is not sufficiently accurate for diagnosis of CO poisoning. Conclusions An alternative biomarker is needed, such as determining the total amount of CO in blood. Although further research is required, we recommend that toxicologists consider all sources of error that can alter COHb concentrations, and in more challenging cases, they should use GC–MS methods to confirm the results obtained by spectrophotometry.
New strategy for carbon monoxide poisoning diagnosis: Carboxyhemoglobin (COHb) vs Total Blood Carbon Monoxide (TBCO)
•Total blood CO (TBCO) is less affected by storage parameters compared to carboxyhemoglobin (COHb).•Correction formula is proposed for analysis in non-optimal storage conditions.•Prediction formula was successfully applied for COHb determination from TBCO.•TBCO is recommended as alternative biomarker to COHb for CO poisoning diagnosis. Diagnosis of carbon monoxide (CO) poisonings has always been a challenging task due to the susceptibility to alterations of the optical state and degradation of blood samples during sampling, transport and storage, which highly affects the analysis with spectrophotometric methods. Methodological improvements are then required urgently because of increased reports of cases with discrepancies between results of the measured biomarker carboxyhemoglobin (COHb) and reported symptoms. Total blood CO (TBCO) measured chromatographically was thus proposed in a previous study as alternative biomarker to COHb. This approach was investigated in this study by comparing the two biomarkers and assessing the effects of various storage parameters (temperature, preservative, time, tube headspace (HS) volume, initial saturation level, freeze- and thaw- and reopening-cycles) over a period of one month. Results show that while for TBCO, concentrations are relatively stable over the observation period regardless of parameters such as temperature, time and HS volume, for COHb, concentrations are altered significantly during storage. Therefore, the use of TBCO as alternative biomarker for CO poisonings has been proposed, since it provides more valid results and is more stable even under non-optimal storage conditions. Additionally, it can be used to predict COHb in cases where sample degradation hinders optical measurement. Furthermore, a correction formula for COHb and TBCO is provided to be used in laboratories or circumstances where optimal storage or analysis is not possible, to obtain more accurate results.
Helium poisoning: new procedure for sampling and analysis
An increasing number of suicidal asphyxiation with a plastic bag with inert gases, and in particular helium (He), have been reported from numerous countries over the last decade. These cases are differently managed and lead to different and variable interpretations. Based on the 12 last cases analysed in the laboratory and on the review of the most recent literature about this topic, updated autopsy guidelines for sampling have been proposed regarding to the samples choice and analytical challenges required by the gaseous state of this substance. Biological samples from airways (lungs lobe) followed by brain and cardiac blood are the best matrices to take during the autopsy to diagnose He exposure. Gaseous samples from trachea, pulmonary bronchi, gastric and cardiac areas are also recommended as alternative samples. The anatomical site of sampling must be carefully detailed, and to this end, forensic imaging constitutes a beneficial tool. Even if He detection is sufficient to conclude to He exposure, He concentrations in samples may be related to He exposure conditions (duration, breathing rate, etc.). A quantification in biological samples could be helpful to document more precisely the case. He concentrations in gaseous samples are reported up to 6.0 μmol/mL (tracheal gas), 2.4 μmol/mL (pulmonary gas), 0.64 μmol/mL (cardiac gas) and 12 μmol/mL (gastric gas). He concentrations in solid/liquid samples are reported up to 28 μmol/g (lungs) and 0.03 μmol/g (cardiac blood). The other matrices usually sampled during autopsy such as urine, peripheral blood, liver, fat matter and kidney appear as not relevant.
Tramadol modulates Lucilia sericata development: clinical larval therapy and forensic insights
Entomotoxicology can inform both forensic reconstructions and clinical larval therapy, yet the consequences of patient-level drug exposure on therapeutic flies remain unexplored. We reared Lucilia sericata on bovine mince fortified with tramadol at therapeutic (0.05 mg/100 g) and lethal (2.0 mg/100 g) levels, alongside blank controls, and assessed development time, wing morphometrics, MALDI-TOF protein profiles, and targeted toxicology of adult tissues. Development time did not differ significantly among treatments, whereas morphometrics showed strong effects of treatment, sex, and their interaction: lethal exposure produced smaller wings, therapeutic exposure larger wings relative to controls, and females exceeded males across treatments. MALDI-TOF PCA primarily separated samples by tissue and experiment (batch), but adult leg spectra consistently distinguished lethal exposure from blank/therapeutic groups, indicating subtle treatment-linked molecular variation. LC-MS/MS detected tramadol in adults exposed to lethal tramadol concentrations in two of three experiments while O-desmethyltramadol was not detected; both analytes were undetectable at therapeutic levels. Collectively, tramadol induced pronounced morphological shifts without measurable developmental delay, a combination that could bias PMI estimates in forensic entomology and, in clinical settings, possibly influence maggot therapy performance. These findings support integrating morphometrics with targeted proteomics and toxicology in entomotoxicological evaluations.
Stability of postmortem methemoglobin: Artifactual changes caused by storage conditions
•We monitored methemoglobin changes in blood samples during storage.•Different temperatures and preservatives have been tested on cardiac and peripheral blood.•Different post-mortem intervals and storage time have been studied.•For short storages, blood samples taken at autopsy should be refrigerated and stored in EDTA preservative.•For longer storages, blood taken at autopsy should be should be frozen with cryoprotectant at −80°C. Hemoglobin is the protein in red blood cells that carries and distributes oxygen to the body. Methemoglobinemia is a blood disorder in which an abnormal amount of methemoglobin (MetHb), a form of hemoglobin (Hb), is produced from either inadequate MetHb reductase activity or too much MetHb production or by exposure to oxidizing agents. This could lead to anoxia and death if it is not treated. However, this parameter has not been investigated as a valid post-mortem indicator because random MetHb levels have been observed in various studies: MetHb increases can be observed due to autoxidation during storage, and MetHb decreases can be observed due to MetHb reductase or microbial activity in post-mortem samples. MetHb variations can also come from the blood state and can interfere in the optical measurements of MetHb. We have studied the post-mortem MetHb concentrations according to various storage conditions. Based on our results, both the post-mortem delay and the delay before analysis should be reduced whenever possible to avoid changes in MetHb. If the analysis is delayed for a short period of time (two weeks), the blood sample taken at autopsy should not be frozen but collected in EDTA preservative and stored under refrigeration (4–6°C) until analysis. If the analysis is delayed for a longer period (more than two weeks), the blood sample should be frozen with cryoprotectant at −80°C or −196°C.
The big puzzle: A critical review of virtual re-association methods for fragmented human remains in a DVI context
During a Disaster Victims Identification (DVI) mission, international protocols rely on interdisciplinary work, especially between specialists from forensic imaging and anthropology. In case of air crashes or explosions, DVI units may face thousands of fragmented human remains (FHRs). The physical re-association of FHRs and the identification process is very complex and challenging, and relies upon expensive and destructive DNA analysis. A virtual re-association (VRA) of these fragments, using Multidetector Computed Tomography (MDCT), could be a helpful tool in forensic anthropology analysis, as it could assist in reducing the number of DNA samples. However, there is no standardized protocol for including such an approach into a DVI procedure. The aim of this study was to summarize and analyze existing techniques through a systematic review and to develop a protocol for virtual re-association of FHRs, adapted to the DVI context. A keyword-based literature search was conducted, focusing on the VRA methods using MDCT imaging and 3D surface scan methodology. Reviews and primary articles, published between 2005 and 2020 in the fields of forensic anthropology, paleoanthropology, archeology, and fracture reduction surgery were sorted out. A total of 45 publications were selected and analyzed based on their content and relevance. The results show that research on the re-association of FHRs increased significantly during the last five years. Seven steps regarding the MDCT-based method for the virtual re-association of FHRs could be identified: acquisition of 3D-images, segmentation of the MDCT-data, post-processing and surface generation, identification of intact and fracture surfaces, identification and registration of matching fragments, and validation of the re-association. The literature is surprisingly sparse regarding the FHRs re-association as a forensic tool, and mainly consists in case reports, whereas validated methods were presented in archeology and surgery publications. However, we were able to adapt the MDCT-based approach for the virtual re-association of the FHRs and propose an innovative protocol for DVI missions. This protocol includes the needed details, from the acquisition of MDCT imaging to the virtual re-association of 3D models and its validation. Each step has to be fully tested, adapted and validated in future studies. •MDCT and physical re-association of fragmented remains are part of the Disaster Victims Identification guidelines.•A protocol for virtual re-association of fragmented human remains (FHRs) would be highly beneficial in a DVI context.•Virtual methods for fragments re-association have been developed for anthropology, archeology or orthopedic surgery.•A critical review of existing methods for virtual re-association of fragmented bones or objects is performed.•Guidelines concerning FHRs re-association, using MDCT-imaging are provided for DVI protocol integration.
Toxicity Assessment of Refill Liquids for Electronic Cigarettes
We analyzed 42 models from 14 brands of refill liquids for e-cigarettes for the presence of micro-organisms, diethylene glycol, ethylene glycol, hydrocarbons, ethanol, aldehydes, tobacco-specific nitrosamines, and solvents. All the liquids under scrutiny complied with norms for the absence of yeast, mold, aerobic microbes, Staphylococcus aureus, and Pseudomonas aeruginosa. Diethylene glycol, ethylene glycol and ethanol were detected, but remained within limits authorized for food and pharmaceutical products. Terpenic compounds and aldehydes were found in the products, in particular formaldehyde and acrolein. No sample contained nitrosamines at levels above the limit of detection (1 μg/g). Residual solvents such as 1,3-butadiene, cyclohexane and acetone, to name a few, were found in some products. None of the products under scrutiny were totally exempt of potentially toxic compounds. However, for products other than nicotine, the oral acute toxicity of the e-liquids tested seems to be of minor concern. However, a minority of liquids, especially those with flavorings, showed particularly high ranges of chemicals, causing concerns about their potential toxicity in case of chronic oral exposure.
Drug vaping applied to cannabis: Is “Cannavaping” a therapeutic alternative to marijuana?
Therapeutic cannabis administration is increasingly used in Western countries due to its positive role in several pathologies. Dronabinol or tetrahydrocannabinol (THC) pills, ethanolic cannabis tinctures, oromucosal sprays or table vaporizing devices are available but other cannabinoids forms can be used. Inspired by the illegal practice of dabbing of butane hashish oil (BHO), cannabinoids from cannabis were extracted with butane gas and the resulting concentrate (BHO) was atomized with specific vaporizing devices. The efficiency of “cannavaping,” defined as the “vaping” of liquid refills for e-cigarettes enriched with cannabinoids, including BHO, was studied as an alternative route of administration for therapeutic cannabinoids. The results showed that illegal cannavaping would be subjected to marginal development due to the poor solubility of BHO in commercial liquid refills (especially those with high glycerin content). This prevents the manufacture of liquid refills with high BHO concentrations adopted by most recreational users of cannabis to feel the psychoactive effects more rapidly and extensively. Conversely, “therapeutic cannavaping” could be an efficient route for cannabinoids administration because less concentrated cannabinoids-enriched liquid refills are required. However, the electronic device marketed for therapeutic cannavaping should be carefully designed to minimize potential overheating and contaminant generation.
Revolution in death sciences: body farms and taphonomics blooming. A review investigating the advantages, ethical and legal aspects in a Swiss context
Taphonomy is the study of decaying organisms over time and their process of fossilization. Taphonomy, originally a branch of palaeontology and anthropology, was developed to understand the ecology of a decomposition site, how site ecology changes upon the introduction of plant or animal remains and, in turn, how site ecology affects the decomposition of these materials. In recent years, these goals were incorporated by forensic science to understand the decomposition of human cadavers, to provide a basis on which to estimate postmortem and/or postburial interval, to assist in the determination of cause and circumstances of death, and to aid in the location of clandestine graves. These goals are achieved through the study of the factors that influence cadaver decomposition (e.g. temperature, moisture, insect activity). These studies have also provided insight into the belowground ecology of cadaver breakdown and allowed to develop useful protocols for mass disaster managements in humanitarian medicine. From the results obtained, new scientific disciplines have arisen, gathered under the word “taphonomics” such as the study of microorganisms living below/on a cadaver (thanatogeomicrobiology), and join the more classical forensic sciences such as anthropology, botany or entomology. Taking into account the specificities of the study object (human cadaver), primordial requirements are needed in terms of security (physical and environmental) as well as ethical and legal concerns which are studied in the Swiss context. The present review aims to present in a first part the concept of human forensic taphonomy facilities (HFTF, also colloquially named “body farm”) leading to an enrichment of forensic sciences with new “taphonomics”. The second part is focused on the mandatory points that must be addressed for a HFTF approach, especially because it requires a specific place to undertake this research which must be performed in conformity with a country’s human ethics and laws.