Postmortem redistribution of THC in the pig

To improve the knowledge of the postmortem redistribution of Δ⁹-tetrahydrocannabinol (THC), an animal model using the Large White pig has been developed, whereby 15 pigs received an intravenous injection of THC (200 µg/kg body weight) and were euthanized 2 h after administration. An autopsy was performed on three pigs immediately after being euthanized while the others were stored in supine position at ambient temperature for 6, 15, 24, or 48 h. THC concentration in blood from the vena cava decreased after death whereas left or right cardiac blood concentrations increased. No blood specimens collected from different sites of the carcasses adequately reflected the perimortem THC concentrations. The highest concentrations of THC at anytime were observed in lung tissue, and brain tissue seemed to present the most stable concentrations over time. This study can assist toxicologists in determining which specimens can, most appropriately, be used for interpretation of cannabinoid concentrations in postmortem specimens.     

Comparative neuropharmacological studies on three pyrrolidine-containing synthetic cathinones

Forensic Toxicology - 3,4-Methylenedioxypyrovalerone (3,4-MDPV) is a prevalent member of α-pyrrolidinophenones, a group of new psychoactive substances, known for its strong psychostimulant...     

Postmortem concentration distribution in fatal cases involving the synthetic opioid U-47700

International Journal of Legal Medicine -     

Detection and quantification of synthetic cathinones and selected piperazines in hair by LC-MS/MS

New psychoactive substances (NPS)—such as synthetic cathinones and piperazines—are defined as substances designed to replicate the effects of traditional illegal drugs, including cocaine, ecstasy and amphetamines. These substances are known to potentially be much more potent than their analogs. In the past, there were many poisonings and deaths associated with NPS. Because of this, NPS identification and quantification have become more important in forensic toxicology. The present work aimed to develop, validate and apply a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method capable of detecting 35 synthetic cathinones and piperazines in hair samples. All target analytes were resolved in a 12 min run time and identified based on the quantifier ion, at least one product ion and the retention time. Depending on the analyte, the calibration curves were linear over a maximal range of 0.01–3 ng/mg. The limits of detection and quantification were within the ranges of 0.006–0.052 ng/mg and 0.008–0.095 ng/mg, respectively. The precision, bias and matrix effect were all within acceptable GTFCh thresholds and the method was free from interferences. The validated method was successfully used to identify synthetic cathinones and piperazines in authentic hair samples (n = 40) from forensic cases, demonstrating its suitability for the screening and quantification of a wide number of new stimulants in hair specimens.     

Postmortem redistribution of ketamine in ocular matrices: A study of forensic relevance

The present study evaluates the postmortem redistribution of ketamine in ocular matrices, such as vitreous humor, aqueous humor, and ocular tissues in an animal model. To understand the redistribution of ketamine and its metabolite (norketamine) in the ocular matrices, an in vivo study was performed in rabbits. The rabbits were divided into two groups: perimortem and postmortem. The postmortem samples were collected at 17 h after the administration of ketamine (40 mg/kg) intravenously. For a better understanding of the metabolism of ketamine in eyes, an ex vivo study was conducted in goat eyes after administration of ketamine intravitreally. The samples were analyzed by LC-MS/MS and the levels of ketamine and norketamine in these matrices were compared with that of whole blood and plasma. The results of the in vivo study showed a decrease in ketamine levels in whole blood and plasma while an increase in ocular matrices at postmortem. Though, in most cases, this increase/decrease was statistically insignificant. Moreover, there was an increase of norketamine level in ocular matrices. Ex vivo study also shows the presence of norketamine in ocular matrices of goat eyes. The presence of norketamine in goat eyes may be indicative of the metabolism of ketamine in the eyes.     

Long-term stability of synthetic cathinones in dried blood spots and whole blood samples: a comparative study

Purpose

The long-term stability of four synthetic cathinones in dried blood spots (DBS) were tested and compared with those of whole blood samples.

Method

A method to determine four cathinones (pentylone, butylone, mephedrone and benzedrone) in DBS was developed and validated. For comparison, the traditional liquid-liquid extraction for the same analytes in whole blood was also performed.

Results

The calibration curve was found to be linear over 25–1000 ng/mL for DBS samples, with a limit of quantification (LOQ) at 25 ng/mL. The interday imprecision and bias results [up to 7.1% relative standard deviation (RSD) and 5.8%, respectively] were much lower than the maximum data recommended by SWGTOX guidelines. The validation results were similar to those of whole blood samples, which showed interday imprecision and bias results of up to 8.1%RSD and 12.3%, respectively, with a linear calibration curve between 10 and 1000 ng/mL and LOQ of 10 ng/mL. A stability study to compare the degradation rate between both matrices at three storage temperatures [room temperature (25 °C), 4 and ??20 °C] and during 90 days proved the poor stability of cathinones in whole blood, where the methylenedioxy cathinones displayed better stability than those with ring substituents. DBS allowed detection of synthetic cathinones after much longer periods than in whole blood samples.

Conclusions

DBS proved, therefore, to be an useful alternative technique to store blood samples. Extraction of DBS is easy and analytes remain stable for much longer periods.

     

GC-PCI-MS/MS and LC-ESI-MS/MS databases for the detection of 104 psychotropic compounds (synthetic cannabinoids,synthetic cathinones,phenethylamine derivatives)

Designer psychotropic compounds continue to be a major problem in Japan and all around the world. Electron impact mass spectrometry (GC-EI-MS) and liquid chromatography with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) data on these compounds have been widely reported. In this report, we present a detection method that has been rarely utilized to analyze these types of compounds, gas chromatography with positive chemical ionization and tandem mass spectrometry (GC-PCI-MS/MS). We report on the development of GC-PCI-MS/MS and LC-ESI-MS/MS databases of 104 psychotropic compounds, including 32 cannabinoid derivatives, 29 cathinone derivatives, 34 phenethylamine derivatives, and several other designer compounds. Using this database, we were able to detect 5 psychotropic compounds in an actual forensic autopsy case. If GC-PCI-MS/MS is used together with the more established methods of GC-EI-MS and LC-ESI-MS/MS, we believe the forensic toxicology community could be better prepared to deal with the challenges of these ever-changing compounds.     

Postmortem distribution pattern of morphine and morphine glucuronides in heroin overdose

The postmortem distribution of morphine and its metabolites was investigated in four cases of heroin overdose to evaluate some of the factors that influence intravasal blood concentrations. Variables included were the chemical stability of morphine conjugates, hemoconcentration, incomplete distribution of the drug and diffusion processes. Blood samples from different sampling sites including the aorta, the infra- and suprarenal portion of the inferior vena cava, the superior vena cava, the femoral and subclavian veins, and the right and left ventricles were examined for morphine, morphine-3-glucuronide and morphine-6-glucuronide, hematocrit and water content. Drug concentrations were determined by HPLC based on the native fluorescence of the analytes. Morphine glucuronides proved to be stable for a time period of 72 h. The water content ranged from 65 to 83% and hematocrit values from 25 to 75%, and were seen as contributory factors to the dramatic differences observed for drug concentrations from different sampling sites. The differences could neither be attributed to incomplete distribution during life-time nor to a diffusion process following the different distribution volumes of morphine and its conjugates. A definite relationship between the ratio of the molar concentrations of morphine and its glucuronides, as assessed in pharmacokinetical studies after morphine dosing, could not be established. For a better understanding more cases and changes over time and tissue concentrations should be analysed.     

Rapid tentative identification of synthetic cathinones in seized products taking advantage of the full capabilities of triple quadrupole analyzer

Forensic Toxicology - In this work, a new approach for synthetic cathinone identification in seized products, consisting of a rapid pseudo-target screening using liquid chromatography coupled to...     

α-Pyrrolidinophenones: a new wave of designer cathinones

Recent years have witnessed a rapid increase in the number and prevalence of novel psychoactive substances (NPSs). Among them, pyrovalerone derivatives, including 3,4-methylenedioxypyrovalerone (3,4-MDPV), α-pyrrolidinopentiophenone (α-PVP), α-pyrrolidinobutiophenone (α-PBP), α-pyrrolidinopropiophenone (α-PPP), α-pyrrolidinohexanophenone (α-PHP), α-pyrrolidinoheptanophenone (α-PHPP), α-pyrrolidinooctanophenone (α-POP) and their substituted analogs, form a subgroup of designer cathinones endowed with highly pronounced psychostimulant effects, and these deserve special attention by healthcare specialists. This review focuses on recent members of this group, their in vitro and in vivo mechanisms of action and pharmacological activities, and their main metabolic pathways. The toxic properties of pyrovalerone derivatives are summarized, along with numerous case reports of fatal and non-fatal intoxications. Pyrovalerone derivatives are also associated with a growing number of reports of DUID (driving under the influence of drugs) and multidrug abuse, suggesting that they should be considered as posing a serious threat to public health.     

Postmortem toxico-kinetics of co-proxamol

Summary Postmortem drug redistribution in suicidal poisonings by co-proxamol (dextropropoxyphene and paracetamol) has been studied. Analytical data for 8 tissue samples, including muscle and fat, up to 8 blood samples, and gastric and small bowel contents were obtained in 4 cases. Blood samples were taken from multiple sites at the start of autopsy and after 24 or 48 h. Concentrations of both drugs were site dependent with the lowest concentrations in peripheral blood. Paracetamol concentrations varied two to threefold and propoxyphene concentrations varied seven to tenfold. Pulmonary artery concentrations of paracetamol did not change significantly with time; propoxyphene concentrations typically increased twofold over 24 h and threefold over 48 h. Propoxyphene concentrations in the inferior vena cava increased unpredictably but occasionally significantly (up to sevenfold). For both drugs the most dramatic elevations of blood concentrations were seen in the aorta; in one case paracetamol rose to 1.9 g/l, 8 times the peripheral blood concentration and 4 times the liver level (454 mg/kg); propoxyphene rose to 191.5 mg/l, 55 times the peripheral blood concentration. This appears to reflect postmortem diffusion of unabsorbed drug from the gastric lumen. It is likely that markedly higher concentrations in the putrefactive fluid from the left pleural cavity as compared with the right also reflect diffusion from the stomach.     

Postmortem diagnosis of hypothermia

The identification of hypothermia as the cause of death has always been somewhat problematic in forensic pathology because of unspecific, inconstant, or even negative macroscopic and microscopic findings. Though the simultaneous presence of frost erythema, Wischnewski spots, hemorrhages into the synovial membrane, bloody discoloration of synovial fluid of the knee, and basal vacuolization of the renal tubular epithelial cells has been indicated as strongly supportive of fatal hypothermia, their absence does not allow the diagnosis of hypothermia to be ruled out. Postmortem biochemical investigations are valuable in detecting adaptation responses to cold stress and metabolic changes that occur following cold exposure. However, ethanol intoxication prevents appearance of adaptation responses to cold, rendering the diagnosis less obvious. Immunohistochemistry, postmortem imaging, and molecular pathology have shown promising results, although at present, they do not provide pathognomonic signs of fatal hypothermia. The aim of this article is to present a review of the literature covering the significance of different postmortem investigations that are associated with hypothermia fatalities.     

MALDI-TOF mass spectrometric determination of four pyrrolidino cathinones in human blood

A rapid and sensitive detection method using matrix-assisted laser desorption ionization (MALDI)–time-of-flight (TOF)–mass spectrometry (MS) was developed for the analysis of four pyrrolidino cathinones: α-pyrrolidinopropiophenone (PPP), 4′-methyl-α-pyrrolidinopropiophenone (MPPP), α-pyrrolidinobutiophenone (PBP), and α-pyrrolidinovalerophenone (PVP). In this method, α-cyano-4-hydroxycinnamic acid was used as the matrix to assist ionization of the cathinones. Each MALDI–TOF–MS spectrum of the cathinones showed not only protonated molecular ion [M + H]⁺ but also several fragment ions having comparable intensities to that of [M + H]⁺. Hence, MPPP and PBP could be clearly discriminated by the mass spectra alone, although these compounds have almost the same mass numbers in their protonated molecular ions. The quantification of MPPP, PBP, or PVP was performed using PPP as internal standard, and that of PPP was performed using PBP as internal standard. The limit of detection was 1 ng/ml, and the quantification range was 2–200 ng/ml for the four cathinones using 20 μl of blood. In a fatal poisoning case in which PVP was abused, the PVP levels in whole blood samples obtained from the right heart, left heart, and femoral vein were 0.597, 0.635, and 0.580 μg/ml, respectively. We recommend the MALDI–TOF–MS method without any chromatography for both identification and quantification of the pyrrolidino cathinones in various matrices in forensic toxicological analysis, because of the simplicity, rapidness, and reliability of the method.     

Postmortem grading of cerebral contusions

In the 1970s, J. H. Adams and other researchers at the Institute of Neurological Sciences, Glasgow, Scotland introduced a grading system for the quantification and analysis of contusions of the brain. They derived a brain contusion index based on regional surface distribution and parenchymal depth of contusions of the brain. Following a subsequent modification of this scheme in the 1980s, they recommended evolving modifications that will fit a variety of possible applications. Having tested the applicability of this grading system for the forensic/medico-legal autopsy, we have encountered some applied anatomic limitations and have derived a modification that addresses these limitations in reference to the forensic/medico-legal autopsy. We recommend a two-tier system based on the Adams’ system, which quantifies contusions of the brain by the gyral spread of contusions and by the parenchymal depth of penetration of contusions with a re-definition of the lobar distinctions and classifications of the brain. Gyral spread is assigned a grading scheme of 0–3 and the parenchymal depth of contusions is assigned a grading scheme of 0–4. A lobar contusion score is derived by multiplying the two assigned grades. A total brain contusion index is derived by summating all the lobar contusion scores. This reproducible grading system can be applied to routine bench forensic neuropathology reporting, court room illustrations and in comparative research analysis of brain trauma subjects.     

Postmortem distribution of mepirapim and acetyl fentanyl in biological fluid and solid tissue specimens measured by the standard addition method

Forensic Toxicology - Mepirapim is a new synthetic cannabinoid. We previously reported that the concentrations of unchanged mepirapim in whole blood and urine were much higher than those of other...     

Postmortem cytokine levels and severity of traumatic injuries

The relationship between postmortem serum cytokine levels and severity of traumatic injuries was studied. The postmortem serum levels of interleukin-6 (IL-6) and interleukin-8 (IL-8) of 131 victims who died from traumatic injury were measured by an enzyme-linked immunosorbent assay method and compared with scores of total abbreviated injury scale (total AIS) and injury severity score (ISS) calculated from detailed autopsy reports. A significant positive correlation was observed between IL-6 and total AIS (rs=0.4508, p<0.0001), between IL-6 and ISS (rs=0.3337, p<0.0001), between IL-8 and total AIS (rs=0.6593, p<0.0001), and between IL-8 and ISS (rs=0.5305, p<0.0001). The significant correlation between cytokine levels and anatomical traumatic severity indicated that the cytokine levels are useful objective indexes of traumatic severity. In addition, the total AIS is a suitable marker to evaluate traumatic severity as the coefficient of correlation between the cytokine levels and the total AIS was higher than that for the ISS values.     

Common Postmortem Computed Tomography Findings Following Atraumatic Death: Differentiation between Normal Postmortem Changes and Pathologic Lesions

Computed tomography (CT) is widely used in postmortem investigations as an adjunct to the traditional autopsy in forensic medicine. To date, several studies have described postmortem CT findings as being caused by normal postmortem changes. However, on interpretation, postmortem CT findings that are seemingly due to normal postmortem changes initially, may not have been mere postmortem artifacts. In this pictorial essay, we describe the common postmortem CT findings in cases of atraumatic in-hospital death and describe the diagnostic pitfalls of normal postmortem changes that can mimic real pathologic lesions.