Postmortem chemistry update part I

Postmortem chemistry is becoming increasingly essential in the forensic pathology routine and considerable progress has been made over the past years. Biochemical analyses of vitreous humor, cerebrospinal fluid, blood and urine may provide significant information in determining the cause of death or in elucidating forensic cases. Postmortem chemistry may essentially contribute in the determination of the cause of death when the pathophysiological changes involved in the death process cannot be detected by morphological methods (e.g. diabetes mellitus, alcoholic ketoacidosis and electrolytic disorders). It can also provide significant information and useful support in other forensic situations, including anaphylaxis, hypothermia, sepsis and hormonal disturbances. In this article, we present a review of the literature that covers this vast topic and we report the results of our observations. We have focused our attention on glucose metabolism, renal function and electrolytic disorder

Hyperthermia and postmortem biochemical investigations

The postmortem diagnosis of heat-related deaths presents certain difficulties. Firstly, preterminal or terminal body temperatures are often not available. Additionally, macroscopic and microscopic findings are nonspecific or inconclusive and depend on survival duration after exposure. The diagnosis of hyperthermia is therefore essentially based on scene investigation, the circumstances of death, and the reasonable exclusion of other causes of death. Immunohistochemistry and postmortem biochemical investigations have been performed by several authors in order to better circumstantiate the physiopathology of hyperthermia and provide further information to confirm or exclude a heat-related cause of death. Biochemical markers, such as electrolytes, hormones, blood proteins, enzymes, and neurotransmitters, have been analyzed in blood and other biological fluids to improve the diagnostic potential of autopsy, histology, and immunohistochemistry. The aim of this article is to present a review of the medicolegal literature pertaining to the postmortem biochemical investigations that are associated with heat-related death

Postmortem biochemical investigations in hypothermia fatalities

Despite the progress made during the past several decades in forensic pathology, the possibilities for the postmortem diagnosis of hypothermia remains relatively limited. Aside from histology and immunohistochemistry, numerous authors have investigated the postmortem biochemistry of hypothermia fatalities. Several biochemical markers (e.g., glucose, electrolytes, hormones, ketone bodies, and neurotransmitters) and various biological samples (e.g., blood, urine, heart, liver, skeletal muscle as well as pericardial and cerebrospinal fluids) have been proposed as potentially useful markers to improve the insufficient diagnostic efficacy of macroscopic and microscopic findings. The aim of this article is to review the medicolegal literature covering the postmortem biochemical investigations that are associated with hypothermia cases as well as report our own research results on this topic where possibl

Genetic analysis of sudden cardiac death victims: a survey of current forensic autopsy practices

Autopsy-negative sudden cardiac deaths (SCD) seen in forensic practice are most often thought to be the result of sudden arrhythmic death syndrome. Postmortem genetic analysis is recommended in such cases, but is currently performed in only a few academic centers. In order to determine actual current practice, an on-line questionnaire was sent by e-mail to members of various forensic medical associations. The questions addressed routine procedures employed in cases of sudden cardiac death (autopsy ordering, macroscopic and microscopic cardiac examination, conduction tissue examination, immunohistochemistry and electron microscopy, biochemical markers, sampling and storage of material for genetic analyses, toxicological analyses, and molecular autopsy). Some questions concerned the legal and ethical aspects of genetic analyses in postmortem examinations, as well as any existing multidisciplinary collaborations in SCD cases. There were 97 respondents, mostly from European countries. Genetic testing in cases of sudden cardiac death is rarely practiced in routine forensic investigation. Approximately 60% of respondents reported not having the means to perform genetic postmortem testing and 40% do not collect adequate material to perform these investigations at a later date, despite working at university hospitals. The survey demonstrated that many of the problems involved in the adequate investigation of SCD cases are often financial in origin, due to the fact that activities in forensic medicine are often paid by and dependent on the judicial authorities. Problems also exist concerning the contact with family members and/or the family doctor, as well as the often-nonexistent collaboration with others clinicians with special expertise beneficial in the investigation of SCD cases, such as cardiologists and geneticists. This study highlights the importance in establishing guidelines for molecular autopsies in forensic medicin

Urinary Analysis of Four Testosterone Metabolites and Pregnanediol by Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry after Oral Administrations of Testosterone

The most frequently used method to demonstrate testosterone abuse is the determination of the testosterone and epitestosterone concentration ratio (T/E ratio) in urine. Nevertheless, it is known that factors other than testosterone administration may increase the T/E ratio. In the last years, the determination of the carbon isotope ratio has proven to be the most promising method to help discriminate between naturally elevated T/E ratios and those reflecting T use. In this paper, an excretion study following oral administration of 40 mg testosterone undecanoate initially and 13 h later is presented. Four testosterone metabolites (androsterone, etiocholanolone, 5α-androstanediol, and 5β-androstanediol) together with an endogenous reference (5β-pregnanediol) were extracted from the urines and the δ13C/12C ratio of each compound was analyzed by gas chromatography-combustion-isotope ratio mass spectrometry. The results show similar maximum δ13C-value variations (parts per thousand difference of δ13C/12C ratio from the isotope ratio standard) for the T metabolites and concomitant changes of the T/E ratios after administration of the first and the second dose of T. Whereas the T/E ratios as well as the androsterone, etiocholanolone and 5α-androstanediol δ13C-values returned to the baseline 15 h after the second T administration, a decrease of the 5β-androstanediol δ-values could be detected for over 40 h. This suggests that measurements of 5β-androstanediol δ-values allow the detection of a testosterone ingestion over a longer post-administration period than other T metabolites δ13C-values or than the usual T/E ratio approac

Procalcitonin and C-reactive protein in pericardial fluid for postmortem diagnosis of sepsis

The aim of this study was to investigate the presence and concentrations of procalcitonin and C-reactive protein in pericardial fluid and compare these levels to those found in the postmortem serum obtained from the femoral blood. Two groups were formed, a sepsis-related fatalities group and a control group. Postmortem native CT scans, autopsies, histology, neuropathology and toxicology as well as other postmortem biochemistry investigations were performed in all cases. Pericardial fluid procalcitonin levels were significantly different between the cases of sepsis-related fatalities and those of the control group. Postmortem serum procalcitonin levels below the detection limit were also reflected in undetectable pericardial fluid levels. Similarly, a large increase in postmortem serum procalcitonin levels was reflected in a large increase of procalcitonin pericardial fluid levels. Based on these findings, pericardial fluid could be an alternative to postmortem serum for the determination of procalcitonin levels in cases where postmortem serum is not available and measurements of procalcitonin are required to circumstantiate the pathogenesis of deat

Analysis of cannabinoids in oral fluid by liquid chromatography-tandem mass spectrometry

A sensitive method was developed for quantifying a wide range of cannabinoids in oral fluid (OF) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). These cannabinoids include ∆9-tetrahydrocannabinol (THC), 11-hydroxy-∆9-tetrahydrocannabinol (11-OH-THC), 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THCCOOH), cannabinol (CBN), cannabidiol (CBD), ∆9-tetrahydrocannabinolic acid A (THC-A), 11-nor-9-carboxy-∆9-tetrahydrocannabinol glucuronide (THCCOOH-gluc), and ∆9-tetrahydrocannabinol glucuronide (THC-gluc). Samples were collected using a Quantisal™ device. The advantages of performing a liquid-liquid extraction (LLE) of KCl-saturated OF using heptane/ethyl acetate versus a solid-phase extraction (SPE) using HLB copolymer columns were determined. Chromatographic separation was achieved in 11.5min on a Kinetex™ column packed with 2.6-μm core-shell particles. Both positive (THC, 11-OH-THC, CBN, and CBD) and negative (THCCOOH, THC-gluc, THCCOOH-gluc, and THC-A) electrospray ionization modes were employed with multiple reaction monitoring using a high-end AB Sciex API 5000™ triple quadrupole LC-MS/MS system. Unlike SPE, LLE failed to extract THC-gluc and THCCOOH-gluc. However, the LLE method was more sensitive for the detection of THCCOOH than the SPE method, wherein the limit of detection (LOD) and limit of quantification (LOQ) decreased from 100 to 50pg/ml and from 500 to 80pg/ml, respectively. The two extraction methods were successfully applied to OF samples collected from volunteers before and after they smoked a homemade cannabis joint. High levels of THC were measured soon after smoking, in addition to significant amounts of THC-A. Other cannabinoids were found in low concentrations. Glucuronide conjugate levels were lower than the method's LOD for most samples. Incubation studies suggest that glucuronides could be enzymatically degraded by glucuronidase prior to OF collectio

One person with two DNA profiles: a(nother) case of mosaicism or chimerism

Nuclear DNA markers, such as short tandem repeats (STR), are widely used for crime investigation and paternity testing. STR were used to determine whether a piece of tissue regurgitated by a dog was part of the penis of a dead, emasculated, man. Unexpectedly, when analyzing the recovered material and a blood sample from the deceased, five out of the 18 loci differed. According to the results, one could have concluded that these samples originated from two different persons. However, taking into account contextual information and data from complementary genetic analyses, the most likely hypothesis was that the deceased was a genetic mosaic or a chimera. Within a forensic genetic context, such genetic peculiarities may prevent associating the perpetrator of an offense with a stain left at a crime scene or lead to false paternity exclusions. Fast recognition of mosaics or chimeras, adapted sampling scheme, as well as careful interpretation of the data should allow avoiding such pitfall

Direct analysis of dried blood spots coupled with mass spectrometry: concepts and biomedical applications

Because of the emergence of dried blood spots (DBS) as an attractive alternative to conventional venous plasma sampling in many pharmaceutical companies and clinical laboratories, different analytical approaches have been developed to enable automated handling of DBS samples without any pretreatment. Associated with selective and sensitive MS-MS detection, these procedures give good results in the rapid identification and quantification of drugs (generally less than 3min total run time), which is desirable because of the high throughput requirements of analytical laboratories. The objective of this review is to describe the analytical concepts of current direct DBS techniques and to present their advantages and disadvantages, with particular focus on automation capacity and commercial availability. Finally, an overview of the different biomedical applications in which these concepts could be of major interest will be presented. Figure Direct analysis of dried blood spot