Introduction: Head hair analysis for drugs and drug metabolites has been used widely with the aim of detecting exposure in the weeks or months prior to sample collection. However, inappropriate ...interpretation of results has likely led to serious miscarriages of justice, especially in child custody cases.
Objective: The aim of this review is to assess critically what can, and perhaps more importantly, what cannot be claimed as regards the interpretation of hair test results in a given set of circumstances in order to inform future testing.
Methods: We searched the PubMed database for papers published 2010-2016 using the terms "hair" and "drug" and "decontamination", the terms "hair" and "drug" and "contamination", the terms "hair" and "drug-facilitated crime", the terms "hair" and "ethyl glucuronide", and the terms "hair", "drug testing" and "analysis". Study of the reference lists of the 46 relevant papers identified 25 further relevant citations, giving a total of 71 citations.
Hair samples: Drugs, drug metabolites and/or decomposition products may arise not only from deliberate drug administration, but also via deposition from a contaminated atmosphere if drug(s) have been smoked or otherwise vaporized in a confined area, transfer from contaminated surfaces via food/fingers, etc., and transfer from sweat and other secretions after a single large exposure, which could include anesthesia. Excretion in sweat of endogenous analytes such as γ-hydroxybutyric acid is a potential confounder if its use is to be investigated. Cosmetic procedures such as bleaching or heat treatment of hair may remove analytes prior to sample collection. Hair color and texture, the area of the head the sample is taken from, the growth rate of individual hairs, and how the sample has been stored, may also affect the interpretation of results.
Toxicological analysis: Immunoassay results alone do not provide reliable evidence on which to base judicial decisions. Gas or liquid chromatography with mass spectrometric detection (GC- or LC-MS), if used with due caution, can give accurate analyte identification and high sensitivity, but many problems remain. Firstly, it is not possible to prepare assay calibrators or quality control material except by soaking "blank" hair in solutions of appropriate analytes, drying, and then subjecting the dried material to an analysis. The fact that solvents can be used to add analytes to hair points to the fact that analytes can arrive not only on, but also in hair from exogenous sources. A range of solvent-washing procedures have been advocated to "decontaminate" hair by removing adsorbed analytes, but these carry the risk of transporting adsorbed analytes into the medulla of the hair therefore confounding the whole procedure. This is especially true if segmental analysis is being undertaken in order to provide a "time course" of drug exposure.
Proposed clinical applications of hair analysis: There have been a number of reports where drugs seemingly administered during the perpetration of a crime have been detected in head hair. However, detailed evaluation of these reports is difficult without full understanding of the possible effects of any "decontamination" procedures used and of other variables such as hair color or cosmetic hair treatment. Similarly, in child custody cases and where the aim is to demonstrate abstinence from drug or alcohol use, the issues of possible exogenous sources of analyte, and of the large variations in analyte concentrations reported in known users, continue to confound the interpretation of results in individual cases.
Conclusions: Interpretation of results of head hair analysis must take into account all the available circumstantial and other evidence especially as regards the methodology employed and the possibility of surface contamination of the hair prior to collection.
Steviol glycosides (SGs), such as stevioside and rebaudioside A, are natural, non-caloric sweet-tasting organic molecules, present in extracts of the scrub plant Stevia rebaudiana, which are widely ...used as sweeteners in consumer foods and beverages. TRPM5 is a Ca
-activated cation channel expressed in type II taste receptor cells and pancreatic β-cells. Here we show that stevioside, rebaudioside A and their aglycon steviol potentiate the activity of TRPM5. We find that SGs potentiate perception of bitter, sweet and umami taste, and enhance glucose-induced insulin secretion in a Trpm5-dependent manner. Daily consumption of stevioside prevents development of high-fat-diet-induced diabetic hyperglycaemia in wild-type mice, but not in Trpm5
mice. These results elucidate a molecular mechanism of action of SGs and identify TRPM5 as a potential target to prevent and treat type 2 diabetes.
► Several parameters for UFLC–MS/MS analysis of benzodiazepine(-like) hypnotics were studied. ► ESI was more efficient than APCI. ► ESI signal was higher when using high pH mobile phase compared to ...low pH. ► More retention with a high pH mobile phase than at low pH using RP-LC. ► Considering the benefits of a high pH mobile phase on both LC and MS, its use should be encouraged.
A sensitive liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous detection of benzodiazepines, benzodiazepine-like hypnotics and some metabolites (7-aminoflunitrazepam, alprazolam, bromazepam, brotizolam, chlordiazepoxide, chlornordiazepam, clobazam, clonazepam, clotiazepam, cloxazolam, diazepam, ethylloflazepate, flunitrazepam, flurazepam, loprazolam, lorazepam, lormetazepam, midazolam, N-desmethylflunitrazepam, nitrazepam, N-methylclonazepam (internal standard), nordiazepam, oxazepam, prazepam, temazepam, tetrazepam, triazolam, zaleplon, zolpidem, zopiclone) in urine and whole blood. Sample preparation was performed on a mixed-mode cation exchange solid phase extraction cartridge. Electrospray ionization was found to be more efficient than atmospheric pressure chemical ionization. The use of a mobile phase of high pH resulted in higher retention and higher electrospray ionization signals than the conventional low pH mobile phases. Considering the benefits of a high pH mobile phase on both chromatography and mass spectrometry, its use should be encouraged. In the final method, gradient elution with 10mM ammonium bicarbonate (pH 9) and methanol was performed on a small particle column (Acquity C18, 1.7μm, 2.1mm×50mm). The optimized method was fully validated.
Human hair absorbs numerous biomolecules from the body during its growth. This can act as a fingerprint to determine substance intake of an individual, which can be useful in forensic studies. The ...cocaine concentration profile along the growth axis of hair indicates the time evolution of the metabolic incorporation of cocaine usage. It could be either assessed by chemical extraction and further analysis of hair bundels, or by direct single hair fibre analysis with mass spectroscopy imaging (MSI). Within this work, we analyzed the cocaine distribution in individual hair samples using MeV-SIMS. Unlike conventional surface analysis methods, we demonstrate high yields of nonfragmented molecular ions from the surface of biological materials, resulting in high chemical sensitivity and non-destructive characterisation. Hair samples were prepared by longitudinally cutting along the axis of growth, leaving half-cylindrical shape to access the interior structure of the hair by the probing ion beam, and attached to the silicon wafer. A focused 5.8 MeV 35Cl6+ beam was scanned across the intact, chemically pristine hair structure. A non-fragmented protonated M+ H+ cocaine molecular peak at m/z = 304 was detected and localized along the cross-section of the hair. Its intensity exhibits strong fluctuations along the direction of the hair's growth, with pronounced peaks as narrow as 50 micrometres, corresponding to a metabolic incorporation time of approx. three hours.
Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) has been employed to rapidly screen longitudinally sectioned drug user hair samples for cocaine and its metabolites ...using continuous raster imaging. Optimization of the spatial resolution and raster speed were performed on intact cocaine contaminated hair samples. The optimized settings (100 × 150 μm at 0.24 mm/s) were subsequently used to examine longitudinally sectioned drug user hair samples. The MALDI-MS/MS images showed the distribution of the most abundant cocaine product ion at
m/z
182. Using the optimized settings, multiple hair samples obtained from two users were analyzed in approximately 3 h: six times faster than the standard spot-to-spot acquisition method. Quantitation was achieved using longitudinally sectioned control hair samples sprayed with a cocaine dilution series. A multiple reaction monitoring (MRM) experiment was also performed using the ‘dynamic pixel’ imaging method to screen for cocaine and a range of its metabolites, in order to differentiate between contaminated hairs and drug users. Cocaine, benzoylecgonine, and cocaethylene were detectable, in agreement with analyses carried out using the standard LC-MS/MS method.
Graphical Abstract
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Three-dimensional (3D) cell cultures, including organ-on-a-chip (OOC) devices, offer the possibility to mimic human physiology conditions better than 2D models. The organ-on-a-chip devices have a ...wide range of applications, including mechanical studies, functional validation, and toxicology investigations. Despite many advances in this field, the major challenge with the use of organ-on-a-chips relies on the lack of online analysis methods preventing the real-time observation of cultured cells. Mass spectrometry is a promising analytical technique for real-time analysis of cell excretes from organ-on-a-chip models. This is due to its high sensitivity, selectivity, and ability to tentatively identify a large variety of unknown compounds, ranging from metabolites, lipids, and peptides to proteins. However, the hyphenation of organ-on-a-chip with MS is largely hampered by the nature of the media used, and the presence of nonvolatile buffers. This in turn stalls the straightforward and online connection of organ-on-a-chip outlet to MS. To overcome this challenge, multiple advances have been made to pre-treat samples right after organ-on-a-chip and just before MS. In this review, we summarised these technological advances and exhaustively evaluated their benefits and shortcomings for successful hyphenation of organ-on-a-chip with MS.
Cnidarian envenomations cause a burning-pain sensation of which the underlying mechanisms are unknown. Activation of TRPV1, a non-selective cation channel expressed in nociceptive neurons, leads to ...cell depolarisation and pain. Here, we show
in vitro and
in vivo evidence for desensitization-dependent TRPV1 activation in cnidarian envenomations. Cnidarian venom induced a nociceptive reactivity, comparable to capsaicin, in laboratory rats, which could be reduced by the selective TRPV1 antagonist, BCTC. These findings are the first to explain at least part of the symptomology of cnidarian envenomations and provide insights into the design of more effective treatments for this global public health problem.
Hair testing is a powerful tool routinely used for the detection of drugs of abuse. The analysis of hair is highly advantageous as it can provide prolonged drug detectability versus that in ...biological fluids and chronological information about drug intake based on the average growth of hair. However, current methodology requires large amounts of hair samples and involves complex time-consuming sample preparation followed by gas or liquid chromatography coupled with mass spectrometry. Mass spectrometry imaging is increasingly being used for the analysis of single hair samples, as it provides more accurate and visual chronological information in single hair samples.Here, two methods for the preparation of single hair samples for mass spectrometry imaging are presented.The first uses an in-house built cutting apparatus to prepare longitudinal sections, the second is a method for embedding and cryo-sectioning hair samples in order to prepare cross-sections all along the hair sample.
Brain tumour identification and delineation in a timeframe of seconds would significantly guide and support surgical decisions. Here, treatment is often complicated by the infiltration of gliomas in ...the surrounding brain parenchyma. Accurate delineation of the invasive margins is essential to increase the extent of resection and to avoid postoperative neurological deficits. Currently, histopathological annotation of brain biopsies and genetic phenotyping still define the first line treatment, where results become only available after surgery. Furthermore, adjuvant techniques to improve intraoperative visualisation of the tumour tissue have been developed and validated. In this review, we focused on the sensitivity and specificity of conventional techniques to characterise the tumour type and margin, specifically fluorescent-guided surgery, neuronavigation and intraoperative imaging as well as on more experimental techniques such as mass spectrometry-based diagnostics, Raman spectrometry and hyperspectral imaging. Based on our findings, all investigated methods had their advantages and limitations, guiding researchers towards the combined use of intraoperative imaging techniques. This can lead to an improved outcome in terms of extent of tumour resection and progression free survival while preserving neurological outcome of the patients.
Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) for the analysis of intact hair is a powerful tool for the detection of drugs of abuse in toxicology and forensic ...applications. Here we present a quick, easy, and reproducible method of preparing longitudinal sections of single hairs. This method improves the accessibility of chemicals embedded in the hair matrix for molecular imaging with mass spectrometry. The images obtained from a single, sectioned hair sample show molecular distributions in the exposed medulla, cortex, and a portion of the cuticle observed as a narrow layer surrounding the cortex. Using MALDI-MS/MS imaging, the distribution of cocaine was observed throughout five longitudinally sectioned drug-user hair samples. The images showed the distribution of the product ion at m/z 182, derived from the precursor ion of cocaine at m/z 304. MetA-SIMS images of longitudinally sectioned hair samples showed a more detailed distribution of cocaine at m/z 304, benzoylecgonine the major metabolite of cocaine at m/z 290 and other drugs such as methadone which was observed at m/z 310. Chronological information of drug intake can be obtained more sensitively. The chronological detail is in hours rather than months, which is of great interest in clinical as well as forensic applications.
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