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⿢Butyrfentanyl and its metabolites undergo time-dependent postmortem redistribution processes.⿢Butyrfentanyl metabolism differs from fentanyl and 3-methylfentanyl.⿢Major metabolites are carboxy- and hydroxybutyrfentanyl. A fatal case of butyrfentanyl poisoning was investigated at the Zurich Institute of Forensic Medicine. At admission at the institute approx. 9h after death (first time point, t1), femoral and heart blood (right ventricle) was collected, as well as samples from the lung, liver, kidney, spleen, muscle and adipose tissue using computed tomography (CT)-guided biopsy sampling. At autopsy (t2), samples from the same body regions were collected manually. Additionally, urine, heart blood (left ventricle), gastric content, brain samples and hair were collected. Butyrfentanyl concentrations and relative concentrations of the metabolites carboxy-, hydroxy-, nor-, and desbutyrfentanyl were determined by LC⿿MS/MS and LC-QTOF. At t1, butyrfentanyl concentrations were 66ng/mL in femoral blood, 39ng/mL in heart blood, 110ng/g in muscle, 57ng/g in liver, 160ng/g in kidney, 3100ng/g in lung, 590ng/g in spleen and 550ng/g in adipose tissue. At t2, butyrfentanyl concentration in urine was 1100ng/mL, in gastric content 2000ng/mL, in hair 11,000pg/mg and brain concentrations ranged between 200⿿340ng/g. Carboxy- and hydroxybutyrfentanyl were identified as most abundant metabolites. Comparison of t1 and t2 showed a concentration increase of butyrfentanyl in femoral blood of 120%, in heart blood of 55% and a decrease in lung of 30% within 19h. No clear concentration changes could be observed in the other matrices. Postmortem concentration changes were also observed for the metabolites. In conclusion, butyrfentanyl seems to be prone to postmortem redistribution processes and concentrations in forensic death cases should be interpreted with caution.

The effects of slaughter age (2 vs. 9 years) and postmortem time (6, 8, 10, 12, 24, 48 and 72 h) on the meat quality and protein changes of the longissimus lumborum muscles of the Algerian Sahraoui dromedary were investigated. Muscles of young dromedaries evidenced a slower acidification process and a significantly higher myofibrillar fragmentation index throughout the postmortem time. The SDS-PAGE of sarcoplasmic and myofibrillar proteins revealed that meat from young dromedaries was characterized by the lowest percentage of myoglobin (p < 0.001) and the highest percentage of desmin (p < 0.01). During postmortem time, a decrease was found for phosphoglucomutase (p < 0.01), α-actinin (p < 0.05) and desmin (p < 0.01) in meat from young dromedaries. Western blot revealed an intense degradation of troponin T in younger dromedaries, with an earlier appearance of the 28 kDa polypeptide highlighting differences in the proteolytic potential between dromedaries of different ages. Principal component analysis showed that meat from young dromedaries, starting from 24 h postmortem, was located in a zone of the plot characterized by higher levels of the myofibrillar fragmentation index, 30 kDa polypeptide and enolase, overall confirming greater proteolysis in younger animals. Data suggest that the investigation of the muscle proteome is necessary to set targeted interventions to improve the aging process of dromedary meat cuts.

Postmortem redistribution (PMR) can result in artificial drug concentration changes following death and complicate forensic case interpretation. Currently, no accurate methods for PMR prediction exist. Hence, alternative strategies were developed investigating the time-dependent postmortem behavior of diazepam, nordiazepam, morphine, codeine, mirtazapine and citalopram. For 477 authentic postmortem cases, femoral blood samples were collected at two postmortem time-points. All samples were quantified for drugs of abuse (targeted; liquid chromatography-tandem mass spectrometry LC-MS/MS) and characterized for small endogenous molecules (untargeted; gas chromatography-high resolution MS (GC-HRMS). Trends for significant time-dependent concentration decreases (diazepam (n = 137), nordiazepam (n = 126)), increases (mirtazapine (n = 55), citalopram (n = 50)) or minimal median postmortem changes (morphine (n = 122), codeine (n = 92)) could be observed. Robust mathematical mixed effect models were created for the generalized postmortem behavior of diazepam and nordiazepam, which could be used to back-calculate drug concentrations towards a time-point closer to the estimated time of death (caution: inter-individual variability). Significant correlations between time-dependent concentration changes of morphine, mirtazapine and citalopram with individual endogenous molecules could be determined; no correlation was deemed strong enough for successful a posteriori estimation on the occurrence of PMR for specific cases. The current dataset did successfully lead to a significant knowledge gain in further understanding the time-dependent postmortem behavior of the studied drugs (of abuse).

•Analytical differentiation between cyclopropylfentanyl and crotonylfentanyl.•Quantitative postmortem values for cyclopropylfentanyl in different matrices.•Significant postmortem redistribution found for cyclopropylfentanyl. A growing number of fatal overdoses involving opioid drugs, in particular involving fentanyl and its analogues, pose an immense threat to public health. Postmortem casework of forensic toxicologists in such cases is challenging, as data on pharmacodynamic and pharmacokinetic properties as well as reference values for acute toxicities and data on potential postmortem redistribution (PMR) mechanisms often do not exist. A fatal case involving cyclopropylfentanyl was investigated at the Zurich Institute of Forensic Medicine and the Zurich Forensic Science Institute; an unknown powder found at the scene was reliably identified as cyclopropylfentanyl by gas chromatography-infrared spectroscopy (GC-IR). Femoral blood samples were collected at two time points after death; 11h postmortem (t1) and during the medico-legal autopsy 29h after death (t2). At the autopsy, additional samples from the heart blood, urine and gastric content were collected. Cyclopropylfentanyl was quantified using a validated liquid chromatography-tandem mass spectrometric (LC–MS/MS) method. Femoral blood concentration of cyclopropylfentanyl at autopsy was 19.8ng/mL (t1=15.7ng/mL; heart blood concentration at autopsy=52.4ng/mL). In the light of the current literature and under the exclusion that no other morphological findings could explain the cause of death, contribution of cyclopropylfentanyl to death was proposed (polydrug use). Significant postmortem concentration increases of cyclopropylfentanyl in femoral blood during 18h after the first sampling were observed, thus indicating a relevant potential to undergo PMR. A central-to-peripheral blood concentration ratio of 2.6 supports this. Consequently, the current case suggests that postmortem cyclopropylfentanyl concentration should always be interpreted with care.

Interpretation of postmortem morphine concentrations in forensic toxicology provides several pitfalls such as missing information on tolerance, analyte stability, or postmortem redistribution (PMR). Recently, it had been shown that computed tomography (CT)-guided collection of biopsies using a robotic arm (virtobot) provides a valuable strategy for systematic studies on time-dependent PMR. Using this technique, time-dependent PMR of morphine and its metabolites was investigated in 12 cases. At admission to the institute (t1), femoral and heart blood (right ventricle) as well as biopsies from the right lung, the right kidney, liver, spleen, and muscle tissue were collected. At autopsy approximately 24 h later (t2), samples from the same body regions were collected again. Additionally, gastric contents, urine, brain tissue, and heart blood from the left ventricle was collected. Morphine, normorphine, hydromorphone, morphine-3-glucuronide, morphine-6-glucuronide, and morphine-sulfate were quantified with LC-MS/MS. In femoral blood, significant increase of morphine concentrations was observed, although ultimately not relevant for forensic interpretation. In the alternative matrices, increases as well as decreases were observed without a clear trend. The morphine metabolites did not exhibit relevant concentration changes. Investigation of underlying redistribution mechanisms indicated that concentration change (i.e., increase) of morphine in femoral blood rather resulted from diffusion processes than from release of morphine from its conjugates. Concentration changes in heart blood might have been caused by redistribution from lung tissue or gastric content. This study also proved that CT-guided collection of biopsies using a virtobot arm is an invaluable tool for future studies on PMR redistribution of other substance groups.

•First case report involving MDAI and 2-MAPB.•Peripheral blood concentration was 38μg/L (MDAI) and 21μg/L (2-MAPB).•No significant postmortem concentration changes in peripheral and heart blood observed. Intoxication cases involving new psychoactive substances (NPS) provide several challenges for forensic toxicologists as data on pharmacodynamic and pharmacokinetic properties are lacking, especially on potency and toxicity. Furthermore, reference values and information on postmortem redistribution (PMR) do not exist so far for most NPS. A fatal case involving the amphetamine-derivatives MDAI (5,6-methylenedioxy-2-aminoindane) and 2-MAPB (1-(benzofuran-2-yl)-N-methylpropan-2-amine) was investigated at the Zurich Institute of Forensic Medicine. At admission at the institute approx. 11h after death (first time point, t1), femoral and heart blood (right ventricle) was collected using computed tomography (CT)-guided biopsy sampling. At autopsy (t2), samples from the same body regions as well as various tissue samples were collected manually. In addition, an antemortem blood sample collected 6h before death was available. MDAI and 2-MAPB were quantified using a validated LC–MS/MS method. A significant concentration decrease between the antemortem and the first peripheral postmortem blood sample was observed, which most probably can be explained by remaining metabolism and excretion within the last 6h prior to death. No significant concentration change was observed between the two postmortem heart blood and peripheral blood samples. Accordingly, MDAI and 2-MAPB did not seem to undergo relevant postmortem redistribution in peripheral and heart blood in the presented case. This is the first study on postmortem redistribution of the new psychoactive substances MDAI and 2-MAPB. However, more studies covering more cases are necessary to generate universal statements on the PMR with these two NPSs.

Genetic sampling, especially high‐quality RNA from wild avian populations, is challenging in wildlife biology due to rapid RNA degradation. Although carcasses could be a potential RNA source, the optimal postmortem sampling time on the avian carcasses under field conditions remains unclear. Here, we carried out a field experiment on the Qinghai‐Tibet Plateau (QTP) and evaluated the relationship between PMI and RNA degradation in three tissue types (muscle, brain, and liver) of the domestic chicken Gallus gallus domesticus carcasses. In the muscle and brain tissues, we found that the RNA Integrity Number (RIN) of samples collected within 60 h postmortem was more than 7.0, suggesting a high RNA extract quality. The following RNA‐seq experiment demonstrated that gene expression profiles of the samples collected within 36 h postmortem were comparable to those of fresh samples (i.e. 0 h), with a low percentage of differentially expressed genes (< 3.0%) observed between samples at 0 and 36 h postmortem. However, in the liver tissue, RNA samples already degraded at 12 h postmortem, showing low RIN values (< 7.0), different gene expression profiles from fresh samples, and a high percentage of differentially expressed genes (15.6%). Therefore, our study suggests that samples from muscle and brain tissues collected within 36 h postmortem are qualified for RNA‐seq analyses. In contrast, only the fresh RNA samples from liver tissue are qualified. Our study provides a practicable and efficient sampling strategy for the transcriptome study on avian populations under extreme environment such as the QTP.

Pericardial fluid (PCF) is a well-preserved cadaveric material in cases without structural damage. The present study investigated fundamental serum components of PCF, including total proteins (TP), albumin (Alb), urea nitrogen (UN), creatinine (Cr), uric acid (UA), glucose (Glu), sodium (Na), potassium (K), chloride (Cl), calcium (Ca) and magnesium (Mg) in PCF with regard to the postmortem and survival periods, and cause of death in serial medicolegal autopsy cases (n=288) with intact pericardial and cardiac structures within 48h postmortem. The amount of PCF (mostly 5–25ml) showed no survival or postmortem time dependence, or difference among the causes of death. For all cases, there were moderate postmortem decreases of Na and Cl, and increases of K and Mg, which were insufficient for application to estimate the time since death; however, characteristic findings with regard to the cause of death were detected in cases of hours-long survival, especially in ‘functional causes of death’: higher Alb, UN, Cr, UA, K and Mg, and lower Na, Cl and Ca in intoxication; lower TP, Alb, Cr, K and Mg, and higher Na and Cl in hypothermia (cold exposure); higher Alb, UN, Cr, UA and Mg, and lower Glu and Ca in hyperthermia (heatstroke). These observations suggest the usefulness of pericardial biomarkers for investigating the cause and process of death to reinforce pathological and toxicological findings.

This study aimed to investigate the effects of postmortem chilling times (4 °C: 0, 2, 8, and 12 h) and subsequent frozen storage durations (-20 °C: 0, 1, 2, and 3 months) on the microstructure and protein properties of tilapia fillets. Tilapia fillets with 8 h of chilling (P8) resulted in highest overall acceptability, hardness, chewiness, and shear force. The thawing losses of tilapia fillets with different postmortem chilling times for the same frozen storage duration were ranked as follows: P12 > P0/P2 > P8. With the prolongation of postmortem chilling times and frozen storage periods, the muscle tissue structure was gradually damaged, with the most severe disruption after 12 h of postmortem chilling time. Tilapia fillets pre-chilled for 8 h showed a 17.63% decrease in Ca 2+ -ATPase activity at 3 months of frozen duration, which was the smallest decrease compared with the other groups. Furthermore, the endogenous fluorescence intensity of P0, P2, P8 and P12 samples decreased by 34.53%, 14.29%, 13.95% and 26.98%, respectively, at the end of frozen storage. Overall, frozen storage durations had a greater effect on the quality of tilapia fillets than postmortem chilling times. In summary, the maximum postmortem chilling time for frozen tilapia fillets is recommended to be 8 h, with significant quality differences when frozen for more than 2 months.

The postmortem redistribution (PMR) phenomenon complicates interpretation in forensic toxicology. Human data on time-dependent PMR are rare and only exist for blood so far. A new method for investigation of time-dependent PMR in blood as well as in alternative body fluids and tissues was developed and evaluated using automated biopsy sampling. At admission of the bodies, introducer needles were placed in liver, lung, kidney, muscle, spleen, adipose tissue, heart, femoral vein, and lumbar spine using a robotic arm guided by a computed tomography scanner (CT). Needle placement accuracy was analyzed and found to be acceptable for the study purpose. Tissue biopsies and small volume body fluid samples were collected in triplicate through the introducer needles. At autopsy (around 24 h after admission), samples from the same body regions were collected. After mastering of the technical challenges, two authentic cases were analyzed as a proof of concept. Drug concentrations of venlafaxine, O-desmethylvenlafaxine, bromazepam, flupentixol, paroxetine, and lorazepam were determined by LC-MS/MS, and the percentage concentration changes between the two time points were calculated. Concentration changes were observed with both increases and decreases depending on analyte and matrix. While venlafaxine, flupentixol, paroxetine, and lorazepam generally showed changes above 30 % and more, O-desmethylvenlafaxine and bromazepam did not undergo extensive PMR. The presented study shows that CT-controlled biopsy collection provides a valuable tool for systematic time-dependent PMR investigation, demanding only minimal sample amount and causing minimal damage to the body. Graphical abstract New strategy for time-dependent postmortem redistribution studies by CT guided biopsy sampling prior to autopsy and comparison of drug concentrations at these two time points using validated LC-MS/MS quantitation.