Study of Root Transparency in Different Postmortem Intervals Using Scanning Electron Microscopy.

In the fields of forensics, the identification of human remains is a recurrent problem. The estimated age at death is one of the copious criteria to be evaluated. In adult teeth, the height of the root dentin transparency is used to estimate age. However, in archaeological material, this phenomenon appears inconstant. The aim of this work was to observe the structural modifications of the sclerotic dentin in the teeth for different postmortem intervals. The study included two parts (retrospective and prospective study) with 21 human monoradicular teeth, from bodies donated to medical science with postmortem intervals (PMIs) of 0, 1, 2 and 5 years and archeological excavation. After inclusion based on resin, section and polishing, the samples were analyzed with a scanning electron microscope (SEM) JSM-7800F®, and the procedure was completed via a semiquantitative analysis of calcium and phosphorus using EDX microanalysis. The analysis showed the existence of tubular and chemical modifications of sclerotic dentin at different PMIs. Our SEM study allowed us to observe a difference in tubule aspects linked to an increased PMI: the loss of peritubular collar and the lumen obstruction of tubules with a hyperdense material. Microanalysis highlighted variations in phosphocalcic ratios among the different groups, especially in the pulp area and the canine. Our hypotheses that explain these differences are based on the postmortem modifications of the crystals of the mineral phase of sclerotic dentin under the influence of chemical and/or bacterial action.

Automated age-at-death estimation by cementochronology: Essential application or additional complication?

It has been repeatedly acknowledged that age-at-death estimation based on dental cementum represents a partial and time-consuming method that hinders adoption of this histological approach. User-friendly micrograph analysis represents a growing request of cementochronology. This article evaluates the feasibility of using a module to accurately quantify cementum deposits and compares the module's performance to that of a human expert. On a dental collection (n = 200) of known-age individuals, precision and accuracy of estimates performed by a developed program (101 count/tooth; n = 20,200 counts) were compared to counts performed manually (5 counts/tooth; n = 975 counts). Reliability of the software and agreement between the two approaches were assessed by intraclass correlation coefficient and Bland Altman analysis. The automated module produced reliable and reproducible counts with a higher global precision than the human expert. Although the software is slightly more precise, it shows higher sensitivity to taphonomic damages and does not avoid the trajectory effect described for age-at-death estimation in adults. Likewise, for human counts, global accuracy is acceptable, but underestimations increase with age. The quantification of the agreement between the two approaches shows a minor bias, and 94% of individuals fall within the intervals of agreement. Automation gives an impression of objectivity even though the region of interest, profile position and parameters are defined manually. The automated system may represent a time-saving module that can allow an increase in sample size, which is particularly stimulating for population-based studies.

Age at death estimation by cementochronology: Too precise to be true or too precise to be accurate?

OBJECTIVES: Cementochronology based on annual deposition of acellular cementum is acknowledged for its superior performance for estimating age-at-death but is also disregarded because of its suspicious effectiveness. This article aims to provide a standardized framework for the validation of the technique and to define and test cementochronology's performance and limitations. MATERIALS AND METHODS: To determine the boundaries of the cementum aging technique, we applied a certified protocol on a sample of 200 healthy canines from individuals of known age, sex, postmortem, and inhumation intervals from anthropological and anatomical collections. We scored readability and preservation of cementum and measured the agreement between estimates, i.e., the precision, and assessed the quality of the accordance between estimates and chronological age, i.e., the accuracy. To investigate the applicability on ancient material, 200 additional canines extracted from archeological assemblages were included. Accuracy and precision were analyzed for each age group in considering postmortem intervals and taphonomical conditions. RESULTS: A strong correlation was found between chronological age and estimates (r = .927; p = .000) but results reveal an association between readability of incremental lines and chronological age (p < .05) and a notable difference in both precision and accuracy between individuals under and over 50 years. Results also demonstrate that taphonomy can be a serious obstacle increasing imprecision by a factor of three. DISCUSSION: Improperly adopted, cementochronology can lead to precise but inaccurate estimations. If methodological, physiological, and taphonomical factors are taken into account, then, and only then, cementochronology will serve as a versatile and powerful tool for age-at-death estimation.

Is bone analysis with µCT useful for short postmortem interval estimation?

The evaluation of the postmortem interval (PMI) is an important consideration in forensic medicine. The time between death and the discovery thereof is extremely important, not only in terms of the legal process, but also for the course of the investigation. At the time of the discovery of human bones, the evaluation of the PMI is extremely difficult. To date, there is no really effective tool for this evaluation. The objective of our study is to characterize the architectural modifications of human bones using micro-tomography (µCT) in the postmortem period. Ten bone samples were extracted from a single fresh human cranial vault (no freezing, no embalming) from a body donation. The samples were conserved in a controlled environment (a laboratory hood at 20 °C with 60% humidity) for 10 weeks. Every 2 weeks after the death and the sample extraction from the vault, the samples were analyzed with µCT (resolution 10 µm, Bruker HR1172 ®). The 3D analysis focused on general 3D data related to the trabeculae: the total volume (TV), the bone volume (BV), and the bone surface (BS), as well as specific trabeculae data; namely: the number of trabeculae (TbN), trabecular thickness (TbTh), the average distance between the trabeculae (TbSp), and the trabecular pattern factor (TbPf). Each sample was observed separately and compared to itself over time; no comparisons among samples were made. We used a linear mixed model for repeated measures (an unstructured covariance pattern model) and post hoc comparisons between each consecutive time using linear contrast with an SAS software package, release 9.3 (SAS Institute, Cary, NC). We showed a statistical difference for BS/BV (p = 0.046) over time, with a significant decrease during the first 2 weeks (p = 0.003; mean decrease, - 0.99, 95% CI [- 1.61; - 0.36]), while TbSp (p < 0.0001) showed a significant increase during the first 2 weeks (p < 0.0001; mean increase, 0.022, 95% CI, [- 0.016; - 0.028]).Our study highlighted architectural trabecular modifications on postmortem bones using the µCT. These modifications occurred at an early stage, during the first 2 weeks of conservation. Complementary work will need to be performed to allow for better understanding of the biological phenomena observed and to create databases of osseous taphonomy, starting with various individuals, mediums of conservation, types of bone, and with varying techniques for analysis.

Domestic Predation of an Elder: A Fatal Dog Attack Case.

We present the case of a 91-year-old woman lived alone at her home with two domestic dogs, that is,, a Labrador Retriever and a Staffordshire Bull Terrier and found dead. The investigation of the scene revealed that the Bull Terrier's jawbone and chest were covered with blood. The autopsy revealed multiple, histologically confirmed, life-threatening skin and bone lacerations without scavenging marks. The punctures and tearing of each of the wounds on the skin were compatible with bites. A left humeral fracture and multiple fractures of the right facial bones were observed. The death was attributed to external hemorrhages due to several dog bites. A veterinary physical and behavioral examination indicated that the Bull Terrier was involved in the attack. A domestic predation hypothesis was deemed here most likely due to the presence of food supplies at the scene, the dog's previous history of attack, and the breed of the dog.

Technical note: early post-mortem changes of human bone in taphonomy with µCT.

Post-mortem interval (PMI) estimation is an important issue in forensic medicine, particularly for criminal purposes and legal limitation periods. The goal of the present study is to examine the evolution of the trabecular cranial vault bone after 4 weeks of conservation in a controlled environment with micro-tomography (µCT) analyses.Four bone samples were extracted from a fresh human cranial vault (a donation to science according to the French law) and conserved in an air-controlled environment. The samples were weighed and µCT scanned at a 10-µm resolution every week after death for a month. The µCT features were identical for every sample. Each set of data from the µCTs was reconstructed, registered, and analyzed in terms of the total volume, bone volume, bone surface, number of trabeculae, trabeculae thickness, and mean distance of the trabeculae. The samples were conserved in a glass box in 20 °C air with 60% humidity in a laboratory hood between each µCT acquisition. Descriptive statistics were determined. Each sample was observed and compared to itself over time.After 1 month of conservation, the mean bone volume (-1.9%), bone surface (-5.1%), and trabecular number (-12.35%) decreased, whereas the mean trabecular separation (+5.55%) and trabecular thickness (+12.7%) increased. Many variations (i.e., increases and decreases) were observed between the extraction of the sample and the end of the 4 weeks of conservation. The present observations may be explained by bone diagenesis. Previous observations have indicated that protein and lipid losses occur with bone weight and volume losses. These diagenesis effects may explain the trabecular modifications observed in the present work. We observed many bone variations with the µCT scans between the beginning and the end of the conservation that had no explanations. Additional studies, particularly studies involving statistics, need to be performed to confirm our observations and explain these results more clearly.

Specific patterns of canine scavenging in indoor settings.

Postmortem animal mutilations due to domestic dogs in isolated domestic deaths are taphonomic modifications regularly observed by forensic pathologists. They are rarely described in the literature; however, even though they present specific patterns. Through 41 cases, 10 at the forensic institute in Lille (France) and 31 at the New York City Office of Chief Medical Examiner (USA), plus 22 cases from the literature, specific locations and patterns of postmortem scavenging lesions are proposed. These lesions are mainly distributed in three locations: the face, especially the nose and the mouth (73.1%), the neck (43.1%), and the arm (shoulder/upper limb [29.2%], hand [26.8%]). We discuss the time span between death and scavenging, the consequences on identification, and comparison with outdoor settings. Outdoor scavenging lesions are mainly located on the trunk and limbs usually sparing the head, which strongly differs from indoor distribution and imply different animal motivations.

[Performing autopsies of all sudden deaths: a public health prevention strategy]. / Pratiquer l'autopsie de toutes les morts subites : un moyen de prévention en santé publique.

INTRODUCTION: In France, the management of sudden death (including nion-forensic autopsies) among adults could be improved. Thee number of sudden deaths may require a change in practice to promote screening for hereditary diseases. The purpose of this study was to identify areas for improvement and to assess the prevalence of non-forensic autopsies. METHODS: A retrospective study (2005-2010) conducted at Lille University Hospital resulted in the selection of 174 non-forensic autopsies of adults who died suddenly. The criteria used were: the geographical origin of the bodies, indication, age, gender and the diagnosis ofdeath. RESULTS: The study found that the annual number of non-forensic autopsies was very low, with proportions ranging from 1.06 to 1.73 per 1,000 deaths in the case of hospital deaths and from 0 to 0.43 per 1,000 deaths in the case of non-hospital deaths. Only 11 non-forensic autopsies of people who died at home were recorded over the study period, including 4 heart disease-related deaths. Overall, the results indicate that sudden death autopsies are poorly managed. DISCUSSION: Non-forensic autopsies are in decline, particularly in the case of deaths outside hospital, despite the fact that they are a crucial consideration for screening among relatives of a person who died sud!denly. The findings suggest that there needs to be an improvement in practice, a fact made possible by recent legislative developlments in France. A number of initiatives have been successful arId give hope that, like the reference centers specializing in unexpected infant deaths, reference centers specializing in sudden de'aths, which allow for more systematic non-forensic autopsies ofadults who die suddenly, might be created.

Skull wounds linked with blunt trauma (hammer example). A report of two depressed skull fractures--elements of biomechanical explanation.

The lesions of the skull following perforating traumas can create complex fractures. The blunt traumas can, according to the swiftness and the shape of the object used, create a depressed fracture. The authors describe through two clinical cases the lesional characteristic of the blunt traumas, perforating the skull using a hammer. In both cases the cranial lesions were very typical: they were geometrical, square shaped, of the same size than the tool (head and tip of the hammer). On the outer table of the skull, the edges of the wounds were sharp and regular. On the inner table, the edges of the wounds were beveled and irregular. The bony penetration in the depressed fracture results from a rupture of the outer table of the bone under tension, in periphery, by the bend of the bone to the impact (outbending) and then, from the inner table with comminuted bony fragmentation. Breeding on the fractures of the size and the shape of the blunt objects used is inconstant and differs, that it is the objects of flat surface or wide in opposition to those of small surface area. Fractures morphologies depend on one hand on these extrinsic factors and on the other hand, of intrinsic factors (structure of the bone). To identify them, we had previously conducted experimental work on cranial bone samples. The bone was submitted to a device for three-point bending. This work had shown properties of thickness and stiffness of the various areas of the vault. Our cases are consistent with these results and illustrate the variability of bone lesions according to region and mode of use of blunt weapons. Many studies have identified criteria for identification of the weapons and the assistance of digital and biomechanical models will be an invaluable contribution with this aim in the future.

Suicidal hanging resulting in complete decapitation--forensic, radiological, and anthropological studies: a case report.

The authors report a case of complete posthanging decapitation. The decapitated corpse lay against a pillar of a road bridge. The head had rolled 5 m from the trunk. The bridge was 7.2 m above the road level. The rope was 3.6 m long, its lower end was 3.6 m from the ground and its diameter was 10 mm. The noose used was a slip knot. Plain X-rays of the skull and cervical spine were obtained. The skull X-rays showed air in the meningeal spaces, in both lateral and third ventricles. The severance plane of the cervical spine was between the third and the fourth cervical vertebrae. No other cervical vertebral injuries were noted. At autopsy, the brain was macroscopically unremarkable except for air in the meningeal veins. The decapitation injuries of the head and the torso corresponded perfectly, without apparent loss of substance. The severance plane was confirmed. Dry bone study was carried out. Except for fractures of the extremities of the spinous processes of the second and third cervical vertebrae, no other bone injury of the spine was seen. The cervical vertebrae displayed numerous osteoarthritic lesions. The traditional hangman's fracture was not found. To the best of our knowledge, this is the first report of complete posthanging decapitation with a severance plane between the third and fourth cervical vertebrae.