Skeletal tissue, a viable option in forensic toxicology? A view into post mortem cases

A critical assessment of the diatom test of rib bone marrow as a supporting procedure in the case of drowning

Diatoms (Bacillariophyta), being single-celled photosynthetic organisms, are widely distributed in aquatic ecosystems around the globe. Their exoskeletons are resistant to most environmental factors as well as chemical reagents in laboratory settings. Moreover, the ornamentation featured on exoskeletons can be used to identify individual diatomaceous species. As a result, the detection of diatoms in the internal organs, and especially rib marrow, of corpses found in water can serve as an important tool for diagnosing drowning as the cause of death as long as passive postmortem penetration of diatoms into those organs is excluded. In the environmental experiments described in this paper, diatoms were detected in rib marrow only when contamination resulted from a mechanical breach of bone integrity and structure, irrespective of the residence time of bone material in the aquatic environment. Our research suggests that the presence of diatom in the rib marrow may be the gold standard in the diagnosis of drowning in the future. Our animal model research dispels one of the doubts, such as the possibility of passive penetration of diatoms into the bone marrow, which is still under discussion in the forensic medicine community.

Hair analysis in postmortem investigations: Case of a skeletonized body

Analysis of hair collected from putrefied or skeletal bodies is always complex and must take into account several pitfalls, such as external contamination and contamination by biological fluids. This work presents a case of particular complexity. A skeletonized body was discovered on a country road. A tuft of brown hair, detached from the scalp, irregular in length, non-oriented, in contact with soil and vegetation, was removed. An anthropological examination was carried out and genetic samples were taken from the right femoral shaft. After about 10 washes with warm water and dichloromethane, the tuft of hair was analyzed without segmentation. General unknown screening was performed by liquid chromatography system coupled to a high-resolution mass spectrometry (LC-HRMS) after incubation in pH 9.5 borate buffer and liquid-liquid extraction. Specific Multiple Reaction Monitoring (MRM) methods for date rape drugs were carried out by liquid chromatography system coupled to a tandem mass spectrometry (LC-MS/MS). The anthropological examination allowed to determine that the victim was a female individual, over 60 years old, the death dating from 3 months to 1 year. Comparison of the DNA results with the Missing Persons Index led to the identification, a 60-year-old woman who disappeared 5 months earlier. Hair analysis showed the presence of oxazepam (361 pg/mg), nordiazepam (54 pg/mg), and alimemazine (5 pg/mg). The interpretation of these concentrations is extremely difficult due to the risk of degradation of the hair cuticle during prolonged stay in the soil, as well as of contamination by putrefactive fluids. The authors discuss the value of using multiple biological and non-biological matrices in this context to improve the interpretation of the results.

Mass Spectrometry Reveals Molecular Effects of Citrulline Supplementation during Bone Fracture Healing in a Rat Model

Bone fracture healing is a complex process in which specific molecular knowledge is still lacking. The citrulline-arginine-nitric oxide metabolism is one of the involved pathways, and its enrichment via citrulline supplementation can enhance fracture healing. This study investigated the molecular effects of citrulline supplementation during the different fracture healing phases in a rat model. Microcomputed tomography (μCT) was applied for the analysis of the fracture callus formation. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) and liquid-chromatography tandem mass spectrometry (LC-MS/MS) were used for lipid and protein analyses, respectively. μCT analysis showed no significant differences in the fracture callus volume and volume fraction between the citrulline supplementation and control group. The observed lipid profiles for the citrulline supplementation and control group were distinct for the different fracture healing stages. The main contributing lipid classes were phosphatidylcholines (PCs) and lysophosphatidylcholines (LPCs). The changing effect of citrulline supplementation throughout fracture healing was indicated by changes in the differentially expressed proteins between the groups. Pathway analysis showed an enhancement of fracture healing in the citrulline supplementation group in comparison to the control group via improved angiogenesis and earlier formation of the soft and hard callus. This study showed the molecular effects on lipids, proteins, and pathways associated with citrulline supplementation during bone fracture healing, even though no effect was visible with μCT.

The DI-SPME Method for Determination of Selected Narcotics and Their Metabolites, and Application to Bone Marrow and Whole Blood Analysis

The present investigation utilised the quick and easy SPME/LC-MS method to determine selected narcotic substances and their metabolites in whole blood. The study included qualitative analysis and validation of the method. Analytes were determined in the linearity range of 25−300 ng/mL. The precision during and between days (in general CV < 13.41%), and the LOD which results in between 0.36 and 11.08 ng/mL, and the LOQ between 1.20 and 36.90 ng/mL were investigated. The validation results obtained, as well as the results of subsequent in-laboratory tests, confirmed the applicability of the method in the analysis of blood samples. An attempt to apply the method to the analysis of bone marrow samples has yielded promising results; however, more detailed studies are needed in this area.

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.

Post Mortem Analysis of Opioids and Metabolites in Skeletal Tissue

Every year, thousands of suspicious deaths are accounted for by an overdose of opioids. Occasionally all traditional matrices are unavailable due to decomposition. Skeletal tissue may pose a valid alternative. However, reference data on postmortem concentrations in bone tissue and bone marrow (BM) is sparse. Therefore, a liquid chromatography--tandem mass spectrometry method was developed and fully validated for the analysis of four opioids and two metabolites (tramadol, O-desmethyltramadol, morphine, fentanyl, norfentanyl, codeine) in bone tissue and BM. Sample preparation was performed using solid phase extraction (BM), methanolic extraction (bone) and a protein precipitation (whole blood). All validation parameters were successfully fulfilled. This method was applied to analyze 22 forensic cases involving opioids. All six opioids were proven to be detectable and quantifiable in all specimens sampled. When tramadol blood concentrations were correlated with bone concentrations, a linear trend could be detected. The same was seen between tramadol blood and BM concentration. A similar linear trend was seen when correlating codeine blood concentration with bone and BM concentration. Although some variability was detected, the same linear trend was seen for morphine. For fentanyl and norfentanyl, the sample size was too small to draw conclusions, regarding correlation. As far as the authors know this is the first-time fentanyl and norfentanyl are quantified in skeletal tissue. In conclusion, due to the absence of reference data for drugs in skeletal tissue, these findings are a step forward toward a more thorough understanding of drug concentration found in postmortem skeletal tissue.

Sample preparation of bone tissue for MALDI-MSI for forensic and (pre)clinical applications

In the past decades, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has been applied to a broad range of biological samples, e.g., forensics and preclinical samples. The use of MALDI-MSI for the analysis of bone tissue has been limited due to the insulating properties of the material but more importantly the absence of a proper sample preparation protocol for undecalcified bone tissue. Undecalcified sections are preferred to retain sample integrity as much as possible or to study the tissue-bone bio interface in particular. Here, we optimized the sample preparation protocol of undecalcified bone samples, aimed at both targeted and untargeted applications for forensic and preclinical applications, respectively. Different concentrations of gelatin and carboxymethyl cellulose (CMC) were tested as embedding materials. The composition of 20% gelatin and 7.5% CMC showed to support the tissue best while sectioning. Bone tissue has to be sectioned with a tungsten carbide knife in a longitudinal fashion, while the sections need to be supported with double-sided tapes to maintain the morphology of the tissue. The developed sectioning method was shown to be applicable on rat and mouse as well as human bone samples. Targeted (methadone and EDDP) as well as untargeted (unknown lipids) detection was demonstrated. DHB proved to be the most suitable matrix for the detection of methadone and EDDP in positive ion mode. The limit of detection (LOD) is estimated to approximately 50 pg/spot on bone tissue. The protocol was successfully applied to detect the presence of methadone and EDDP in a dosed rat femur and a dosed human clavicle. The best matrices for the untargeted detection of unknown lipids in mouse hind legs in positive ion mode were CHCA and DHB based on the number of tissue-specific peaks and signal-to-noise ratios. The developed and optimized sample preparation method, applicable on animal and human bones, opens the door for future forensic and (pre)clinical investigations.