Postmortem Distribution and Postmortem Redistribution of Carbofuran-7-Phenyl Glucuronic Acid in Rabbits

OBJECTIVES

To establish a carbofuran intragastric administration death model in rabbits, and to observe the postmortem distribution and postmortem redistribution of carbofuran-7-phenyl glucuronic acid (Glu-7PH) in rabbits.

METHODS

The postmortem distribution: Rabbits were given an administration of 1/2LD50, LD50, 2LD50 carbofuran. Dead rabbits were dissected immediately. Rabbits that had remained alive 2 hours were sacrificed by carbon dioxide (CO₂) inhalation and dissected immediately. The myocardium, cardiac blood, liver, spleen, lung, kidney, brain and right hindlimb muscle were collected. The postmortem redistribution: After giving an administration of 4LD50 carbofuran, the myocardium, cardiac blood, liver, spleen, lung, kidney, brain, and right hindlimb muscle were collected at 0, 12, 24, 48, and 72 h postmortem in supine position at 15 ℃ room temperature. The quantity of Glu-7PH was determined by LC-MS/MS.

RESULTS

The postmortem distribution: Among the three dose groups, there were significant differences in the quantities of Glu-7PH in different tissues. The postmortem redistribution: There was no significant difference in the Glu-7PH quantities in cardiac blood, mycardium, spleen, kidney, brain and right hindlimb muscle, but there was a significant difference in the Glu-7PH quantities in the liver and lung.

CONCLUSIONS

The mycardium, cardiac blood, liver, lung, kidney, brain and hindlimb muscle of rabbits can be used as appropriate samples for Glu-7PH detection. However, it should be noted that Glu-7PH was redistributed postmortem in rabbit liver and lung.

Postmortem metabolomics: Correlating time-dependent concentration changes of xenobiotic and endogenous compounds

Postmortem redistribution (PMR) describes the artificial postmortem concentration changes of xenobiotics that may pose major challenges in forensic toxicology. Only a few studies have systematically investigated time-dependent postmortem drug concentration changes so far and the a posteriori estimation of the occurrence of PMR is not yet possible. In this context, the general concept that postmortem biochemical changes in blood might parallel drug redistribution mechanisms seems promising. Thus, the current study investigated the possible correlations between time-dependent postmortem concentration changes of xenobiotic and endogenous compounds; exemplified for authentic morphine (n = 19) and methadone (n = 11) cases. Peripheral blood samples at two time-points postmortem were analyzed for morphine and methadone concentrations and an (un)targeted postmortem metabolomics approach was utilized to combine targeted quantitative analysis of 56 endogenous analytes and untargeted screening for endogenous compounds (characterizing 1174 features); liquid and gas chromatography-mass spectrometry was used respectively. Individual statistically significant correlations between morphine/methadone and endogenous compounds/features could be determined. Hence, the general applicability of the proposed concept could successfully be confirmed. To verify the reproducibility and robustness of the correlating behavior, a larger dataset must be analyzed next. Once a marker/set of markers is found (e.g. robust correlation with specific xenobiotic or xenobiotic class), these could be used as surrogates to further study the time-dependent PMR in a broader variety of cases (e.g. independent of a xenobiotic drug present). A crucial next step will also be the attempt to create a statistical model that allows a posteriori estimation of PMR occurrence of xenobiotics to assist forensic toxicologists in postmortem case interpretation.

Forty-Three Fatalities Involving the Synthetic Cannabinoid, 5-Fluoro-ADB: Forensic Pathology and Toxicology Implications

Forty-three fatalities involving the potent synthetic cannabinoid, 5-Fluoro-ADB, are summarized. For each case, a description of the terminal event, autopsy findings, cause of death, qualitative identification of 5-Fluoro-ADB and its ester hydrolysis metabolite, 5-Fluoro-ADB metabolite 7, in urine, and the quantitative values obtained in the blood specimens are outlined. Central blood concentrations ranged from 0.010 to 2.2 ng/mL for 5-Fluoro-ADB and 2.0 to 166 ng/mL for 5-Fluoro-ADB metabolite 7. Peripheral blood concentrations ranged from 0.010 to 0.77 ng/mL and 2.0 to 110 ng/mL for 5-Fluoro-ADB and 5-Fluoro-ADB metabolite 7, respectively. The majority of cases resulted in central to peripheral blood concentration ratios greater than 1 for 5-Fluoro-ADB (58%) and 5-Fluoro-ADB metabolite 7 (71%) suggesting that postmortem redistribution occurs to some extent. Combining the increased cardiac weight and/or gastric volume and toxicology data identifying 5-Fluoro-ADB, it is hypothesized that abuse of this substance may precipitate a dysrhythmia and cause sudden death.

[Cause of Death: 'Intoxication' - a Matter of the Concentration?]

Cause of Death: 'Intoxication' - a Matter of the Concentration? Abstract. Elucidation of the cause of death is one of the main reasons for medico-legal investigations. In clinical toxicology, the severity of a given poisoning is typically assessed with the blood concentration of a pharmacologically or toxicologically active compound. Such an interpretation proves to be difficult or even impossible in postmortem toxicology. Numerous biochemical and biological processes beginning immediately after death may render the calculated drug concentration unreliable. Concentrations obtained from postmortem samples do not necessarily reflect the blood concentration at the time of death. A prediction if and to what extent such postmortem changes might have occurred is still impossible for individual cases. Interpretation therefore needs to be done with care, considering case circumstances and all available information.

Detection of Acetaminophen-Protein Adducts in Decedents with Suspected Opioid-Acetaminophen Combination Product Overdose

Acetaminophen overdose is a leading cause of drug-induced liver failure in the United States. Acetaminophen-protein adducts have been suggested as a biomarker of hepatotoxicity. The purpose of this study was to determine whether protein-derived acetaminophen-protein adducts are quantifiable in postmortem samples. Heart blood, femoral blood, and liver tissue were collected at autopsy from 22 decedents suspected of opioid-acetaminophen overdose. Samples were assayed for protein-derived acetaminophen-protein adducts, acetaminophen, and selected opioids found in combination products containing acetaminophen. Protein-derived APAP-CYS was detected in 17 of 22 decedents and was measurable in blood that was not degraded or hemolyzed. Heart blood concentrations ranged from 11 ng/mL (0.1 μM) to 7817 ng/mL (28.9 μM). Protein-derived acetaminophen-protein adducts were detectable in liver tissue for 20 of 22 decedents. Liver histology was also performed for all decedents, and no evidence of centrilobular hepatic necrosis was observed.

Postmortem redistribution of lidocaine after epidural injection in beagle dogs

OBJECTIVES

An animal model using beagle dog has been established to investigate the postmortem redistribution of lidocaine.

MATERIALS AND METHODS

18 dogs were euthanized and injected lidocaine (13 mg/kg) via epidural immediately. An autopsy was performed at 0, 12, 24, 48, 72, 96 hours after drug administration. All animals were stored in supine position at room temperature. For the other groups, lidocaine was given via epidural 6, 12, 24 hours after dogs were euthanized. Followed treatments were as above described. All samples were treated for detection of the concentration of lidocaine.

RESULTS

It was found that lidocaine could diffuse via blood vessel rapidly post administration. And the concentration of lidocaine in the blood from ventriculus sinister increased obviously in a time-dependent manner. Meanwhile, the postmortem tissue distribution of lidocaine was significantly different. However, the process of postmortem redistribution of lidocaine was obviously delayed in dogs which were given drugs after death.

CONCLUSIONS

Together results revealed the process of postmortem redistribution of lidocaine via epidural injection, and provided the method to distinguish the lidocaine-induced death and drug administration after death.

Distribution of enantiomers of methadone and its main metabolite EDDP in human tissues and blood of postmortem cases

Knowledge concerning the distribution of methadone in postmortem human tissue and the effect of postmortem redistribution on methadone is today limited making the choice of a suitable substitute for femoral blood difficult when this is not available. Cardiac blood, femoral blood, muscle, and brain tissue concentrations of the enantiomers of methadone and its metabolite 2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolinium were recorded for 155 postmortem cases. Brain and muscle tissue concentrations exceeded the femoral blood concentrations with a median fold of 2.3 and 1.6, respectively, but both had a better correlation than cardiac blood to femoral blood concentrations. The Kruskal-Wallis test showed a significant dependency on time and body mass index for some of the matrix ratios over femoral blood. We conclude brain or muscle tissue may constitute a better alternative for measurement of methadone than cardiac blood for situations in which femoral blood is not available, despite concentrations in both matrices being systematically higher.

An examination of the postmortem redistribution of fentanyl and interlaboratory variability

Fentanyl is a synthetic opioid agonist used for pain control. Often administered as a transdermal patch, it is an interesting drug for study of postmortem redistribution. We hypothesized that fentanyl concentrations would increase over time after death, as measured in blood drawn on the day prior to autopsy and in blood drawn at the time of autopsy in ten cases where fentanyl patches were identified at the scene. Concentrations were compared, and heart blood to femoral blood ratios were calculated as markers of postmortem redistribution. Fentanyl concentrations measured in peripheral blood drawn the day of autopsy (peripheral blood 2 [PB2]) were higher than those drawn the day prior to autopsy (peripheral blood 1 [PB1]) with a mean ratio (PB2/PB1) of 1.80. The ratio of heart blood concentrations (HB) to femoral blood concentrations drawn at autopsy (PB2) had a mean ratio (HB/PB2) of 1.08. Some cases had blood from the same source analyzed at two different laboratories, and concentrations of fentanyl in those samples showed inter- and intralaboratory differences up to 25 ng/mL. Postmortem fentanyl concentrations may be affected by antemortem factors, postmortem redistribution, and laboratory variability. Forensic pathologists must use caution in interpreting fentanyl levels as part of death investigation.