Audrey Farrugia

Efficiency evaluation of a DNA extraction and purification protocol on archival formalin-fixed and paraffin-embedded tissue.

Formalin-fixed and paraffin-embedded tissue (FF-PET) is an invaluable resource for retrospective molecular genetic studies, but the extraction of high-quality genomic DNA from FF-PET is still a problematic issue. Despite the range of DNA extraction methods currently in use, the association of phenol-chloroform extraction and silica-based purification protocols, reported in ancient DNA studies on archaeological bones, has, to our knowledge, not been used for DNA extraction from FF-PET yet. The present study compared the efficiency of three DNA extraction and purification protocols from two different FF-PET substrates, heart and liver, by using quantitative PCR and multiplex amplification. We showed that the method, using phenol-chloroform and the QIAamp DNA mini Kit (Qiagen), was the most effective DNA extraction and purification method and that the DNA quantity extracted from liver is statistically more important than that extracted from heart. Autosomal STR typing by multiplex amplifications gave partial allelic profiles with only small size products (less than 300 bases) amplified, suggesting that DNA extracted from FF-PET was degraded. In conclusion, the protocol presented here, previously described in studies on ancient bones, should find application in different molecular studies involving FF-PET material.

Ricochet of a bullet in the spinal canal: a case report and review of the literature on bullet migration.

Abstract:  Ricochet of a bullet in the spinal canal is well known by neurosurgeons but relatively not a common event in usual medico‐legal autopsy practice. This article presents a homicide case of a penetrating gunshot injury of the lumbar spine through the T12‐L1 intervertebral foramen with active movement of the projectile within the spinal canal to the L5‐S1 level. This case illustrates a bullet intradural and intramedullary active movement because of a ricochet of the body of T12 with active redirection of the path. In the current literature, different types of migration in caudal or cranial direction, intradural, or intramedullary are reported. If spontaneous migration of T10 to S1 seems to be more frequent, some authors reported a C1 to S2 migration. Such migration could be asymptomatic or induce neurological impairment. The medico‐legal consequences of these migrations within the spinal canal are described.

Destabilization and intracranial fragmentation of a full metal jacket bullet

We report a case with an atypical entrance wound as a result of a destabilized full metal jacket bullet penetration. The destabilized bullet by an impact with the dorsal hand experiences a yawing to tumbling motion in flight. The large angle of yaw induces a larger presenting profile upon impact that contributes, associated to a rapid deceleration, to a greater mechanical force on the projectile structure and a fragmentation into core and jacket. Forensic pathologists have to be aware that the metal jacket bullet could tend to break up outside or inside the body particularly after a shooting through a target. This phenomenon induces atypical entrance wounds and atypical X-ray presentation.

Diagnostic of Drowning in Forensic Medicine

The diagnostic of drowning is described in the literature as one of the most difficult in the field of forensic medicine (Piette & De letter, 2006). In fact, the external examination and the autopsy findings are in most of the cases not specific and the laboratory investigations are controversially appreciated by the scientific community. The main goal in this field is to differentiate a death by submersion from a immersion of a body. Death of a victim found in water should not always be related to drowning (Knight, 1991). It is important to remind that the death by drowning is defined as a death due to submersion in a liquid and the mechanism in acute drowning is hypoxemia and irreversible cerebral anoxia (D.J. Di Maio & V.J.M. Di Maio 1989).

High risk of misinterpreting hair analysis results for children tested for methadone

The major problem after testing the hair of a child for drugs is the interpretation of the findings. In 2016, the laboratory received several hair specimens with the request to verify if there was any evidence of previous methadone exposure by the donor of the sample. Case 1 was a child admitted to the Emergency Unit for intense sedation and breathing difficulties. Cases 2-4 involved children found dead at home. In all cases, methadone and EDDP, its metabolite, were found in blood. After decontamination, the hair was analysed with LC-MS/MS for methadone and EDDP. The LOQ for both drugs was 10pg/mg. Concentrations were in the range 60-1590 and <10-220pg/mg for methadone and EDDP, respectively. In all of the cases, segmental analysis revealed approximately the same amount of drug along the hair lock. As a consequence, contamination was considered as an issue and interpretation of the results was a challenge that deserves particular attention. It must be considered that the amount of hair from children, available for analysis, can be low, particularly when several drugs have to be tested. This has consequences on the limit of quantitation and the identification of the metabolite(s). It must be also noted that hair from children is finer and more porous in comparison with adult (risk of higher contamination by sweat versus adults). It is very difficult to put any window of detection when testing for drugs in young children as hair growing is asynchronous. It is even more complicated as it has been demonstrated that drugs can be incorporated during pregnancy in the hair of the foetus, which will contribute to the positive findings after delivery. Several weeks or months after delivery, identification of a drug in hair can indicate: 1, in-utero exposure, or 2, exposure after delivery, or 3, a mix of both situations. Whereas the detection of drugs in a childs hair unambiguously shows drug handling in the environment of the child, it is difficult to distinguish between systemic incorporation into hair after ingestion or inhalation and external deposition into hair from smoke, dust, or contaminated surfaces. However, the interpretation of hair results with respect to systemic or only external exposure is particularly important in case of children for a realistic assessment of the toxic health risk. Practising scientists have the responsibility to inform the child protection authorities, courts, etc about these limitations.

The benefits and pitfalls of post-mortem computed tomography in forensic external examination: A retrospective study of 145 cases

OBJECTIVE Nowadays, post-mortem computed tomography (PMCT) has become an integral part of Forensic practice. The purpose of the study was to determine PMCT impact on diagnosis of the cause of death within the context of the external examination of the body, when autopsy has, at first, not been requested. MATERIAL AND METHODS We reviewed the records of 145 cases for which unenhanced PMCT was performed in addition to the external examination of the body from January 2014 to July 2015 at the Institute of Forensic medicine in Strasbourg (France). We confronted final reports from forensic pathologist to the corresponding PMCT reports. Data were collected in a contingency table and the impact of PMCT on the final conclusions of the forensic pathologist was evaluated via a Chi2 test. RESULTS PMCT results significantly impact the final conclusions of forensic pathologist (p<0,001). In some cases, PMCT permits etiological diagnosis by revealing a cause of death hidden from external examination (mainly natural death) or by supporting the clinical findings of the forensic pathologist. In other cases (traumatic death), PMCT enables fast and exhaustive lesion assessment. Lastly, there are situations where PMCT may be ineffective (intoxication, hanging or some natural deaths). CONCLUSION Performing PMCT within the context of the external examination of the body when autopsy has, at first, not been requested could bring significant benefits in diagnosing the cause of death. The impact of PMCT varies depending on the circumstances of death.

Retrospective Demonstration of 25I-NBOMe Acute Poisoning Using Hair Analysis

BACKGROUND The abuse of new psychoactive substances or NPS has been dramatically increasing all around the world since the last half of the year 2000 and has become a serious public health problem. NPS are a challenge for the worldwide forensic community due to the difficulties to accurately document the cases. The N-benzylmethoxy (NBOMe) group is a new class of hallucinogenic designer drugs and has gained importance in recent years. 25I-NBOMe (2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)- methyl]ethanamine) is an analog of the 2C series of psychedelic phenethylamine drugs that contain an N-methoxybenzyl substituent, which significantly affects their pharmacological activities. It is a potent agonist of 5-HTA receptors and a severe hallucinogenic drug, with numerous irreversible psychedelic effects which can last from 5 to 10 hours. It is consumed most often in the form of drops or blotters by the transmucosal, sublingual or intranasal routes. The active dosage is very low, supposed to be less than 100 µg. The literature is poor in reporting cases where 25I-NBOMe was identified. Only very few clinical cases of over dosages were published, suggesting a low prevalence of this compound. METHODS We present a retrospective demonstration of 25I-NBOMe acute poisoning with dramatic outcome, using hair analysis. Two hair strands, measuring 9.5 cm, were collected 6.5 months after drug consumption during a forensic clinical evaluation of brain dysfunctions after cardiorespiratory arrest and were analyzed by ultra-high performance liquid chromatography system coupled to a tandem mass spectrometry (UPLC-MS/MS) and using two specific transitions: m/z 428.1 > 121.2 (quantification) and 428.1 > 90.6 (confirmation). Hair strands were segmented to determine the historic pattern of drug use and differentiate a single exposure from a chronic exposure. The hair test result for 25I-NBOMe was the following: not detected (0-2 cm), not detected (2-4 cm), 1.0 pg/mg (4-6 cm), 4.9 pg/mg (6-8 cm) and not detected (8-9.5 cm). RESULT The result of the segment 6-8 cm coincides with the date of consumption (calculated with a hair growth rate at 1 cm/month) and the low concentration detected in the segment 4-6 cm probably corresponds to the contribution of dormant hair. The toxicological significance of the measured concentrations is difficult to determine because this is the first case dealing with hair analysis for 25I-NBOMe. CONCLUSION The use of hair analysis for NPS is still at the initial stages. In particular, little is known about the incorporation into the keratin matrix after intake and the correlation between dosage frequency of use, and hair concentrations. Under these circumstances, NPS hair analysis should be cautiously interpreted by experienced forensic toxicologist.

Interpretation of Cannabis Findings in the Hair of Very Young Children: Mission Impossible

BACKGROUND Hair has been suggested since the middle of the 90s to be a suitable matrix to document repetitive exposure to cannabis. Because it is possible to detect Δ9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) in cannabis smoke, the identification of the metabolite, 11-nor-Δ9-tetrahydrocannabinol carboxylic acid (THC-COOH) has been considered to allow the discrimination of active use. OBJECTIVE Although the identification of an active compound in a childs hair shows contamination of the local environment, it is a challenge to discriminate between hair incorporation after ingestion or inhalation and environmental external deposition from dust, smoke, or even contaminated surfaces by hand contact. However, it is particularly important in case of children to correctly interpret the data, particularly for a realistic assessment of the health risk. We present here a series of hair tests for cannabis where the interpretation was almost impossible to establish. METHOD Hair specimens were collected during the autopsy of the 12 children, aged 2 to 24 months, either deceased from shaken baby syndrome (SBS, n=4), mechanic asphyxia (MA, n=1) or sudden infant death (SID, n=7) during January 2015 to April 2017. After decontamination, the hair specimens were tested for THC, CBN and CBD and THC-COOH. The whole length of hair was submitted to analysis. RESULTS The amount of hair from children can be as low as 8 mg. This may affect the limit of quantitation of all drugs, but particularly THC-COOH. Eight from twelve hair tests were positive for cannabis markers, i.e. THC (39 to 1890 pg/mg, n=8), CBN (< 5 to 1300 pg/mg n=8), CBD (10 to 2300 pg/mg, n=8) and THC-COOH (not detected to < 0.5 pg/mg, n=5). In 4 cases from 8 positive findings, it was not possible to test for THC-COOH (not enough material). CONCLUSION Establishing a window of detection when testing for drugs in young children is a very complicated task. Hair from children is finer and more porous in comparison with adult (the risk of contamination from sweat and environmental smoke is higher than in adults). The final interpretation of cannabinoid findings in the childrens hair is very complicated as this can result from in utero exposure (although none of the mother admitted cannabis use during pregnancy), oral cannabis administration by the parents to achieve sedation, close contact to cannabis consumers (hands, bedding, dishes) and inhalation of side-stream smoke. Over-interpreting cannabis findings in hair can have very serious legal implication in child protection cases. Practicing scientists have the responsibility to inform the child protection authorities, courts, etc. about these limitations.