Circumstances of Death and Diagnostic Difficulties in Brushfire Fatalities

Thunder storm mortality: Issues of medicolegal concern

Thunderstorms refer to atmospheric disturbances that are associated with electrical discharges in the form of lightning, with acoustic effects from thunder. They involve the rapid upward movement of warm, moist air which then cools and condenses creating typical cumulonimbus clouds with precipitation. Thunderstorms range in severity but are usually associated with heavy rains, winds and sometimes sleet, hail and snow. If the intensity of a storm increases there may be tornadoes or cyclones. In cases with lightning strikes and minimal or no rain there is an associated risk for the development of quite devastating wild (bush) fires. Lightning strikes may also be associated with the development, or an exacerbation, of potentially lethal natural cardiac or respiratory diseases.

Nucleic Acids Persistence-Benefits and Limitations in Forensic Genetics

The analysis of genetic material may be the only way to identify an unknown person or solve a criminal case. Often, the conditions in which the genetic material was found determine the choice of the analytical method. Hence, it is extremely important to understand the influence of various factors, both external and internal, on genetic material. The review presents information on DNA and RNA persistence, depending on the chemical and physical factors affecting the genetic material integrity. One of the factors taken into account is the time elapsing to genetic material recovery. Temperature can both preserve the genetic material or lead to its rapid degradation. Radiation, aquatic environments, and various types of chemical and physical factors also affect the genetic material quality. The substances used during the forensic process, i.e., for biological trace visualization or maceration, are also discussed. Proper analysis of genetic material degradation can help determine the post-mortem interval (PMI) or time since deposition (TsD), which may play a key role in criminal cases.

Burn index, burn characteristics and carboxyhemoglobin levels in indoor fire-related deaths: Significance and interpretation of the autopsy findings

INTRODUCTION

The Burn Index (BI) is a significant clinical prognostic parameter for patients with burns. It simultaneously considers major mortality risk factors: age and burns extensivity. Despite the inability to distinguish between ante- and post-mortem burns, their characteristics on autopsy might indicate if a significant thermal injury occurred before the onset of death. We investigated whether autopsy BI, burn extensivity, and severity could tell whether burns were the concurrent cause of fire-related death (FRD), even if the body remained in a fire.

MATERIAL AND METHODS

Ten-year retrospective study analyzed FRD that occurred at the scene in a confined space. Soot aspiration was the main inclusion criterion. Autopsy reports were reviewed for demographic data, burn characteristics (degree, Total Body Surface Area burned- TBSA), coronary artery disease, and blood ethanol. We calculated the BI as a sum of the victim's age and percentage of TBSA affected by 2nd, 3rd and 4th-degree burns. Cases were divided into two groups: those with COHb≤ 30% and with COHb> 30%. Subjects with burned TBSA≤ 40% were analyzed separately afterward.

RESULTS

The study included 53 males (71.6%) and 21 females (28.4%). No significant difference in age was observed between groups (p > 0.05). COHb≤ 30% had 33, and COHb> 30% had 41 victims. BI and burns extensivity (TBSA) had significant negative correlation with COHb values (ρ = -0.581, p < 0.01 and ρ = -0.439, p < 0.01, respectively). Both were significantly higher in subjects with COHb≤ 30% compared to those with COHb> 30% (140.7 ± 29.57 vs. 95.49 ± 38.49, p < 0.01 and 98 (13-100) vs. 30 (0-100), p < 0.01, BI and TBSA respectively). BI had excellent and TBSA fair performance for detection of subjects with COHb≤ 30% on ROC curve analysis (AUCs 0.821, p < 0.001 and 0.765, p < 0.001), with optimal cut-off values: BI≥ 107 (sensitivity 81.3%, specificity 70.7%) and TBSA≥ 45 (sensitivity 84.8%, specificity 70.7%). On logistic regression analysis BI≥ 107 was independently associated with COHb≤ 30% values (aOR 6; 95%CI 1.55-23.37). The same holds for the presence of 3rd-degree burns (aOR 5.9; 95%CI 1.45-23.99). In the subgroup of subjects with TBSA≤ 40% burned, those with COHb≤ 50% were significantly older than victims with COHb> 50% (p < 0.05). Here BI≥ 85 was a particularly good predictor for detection of subjects with COHb≤ 50% (AUC=0.913, p < 0.001, 95% CI 0.813-1.00; sensitivity 90.9%, specificity 81%).

CONCLUSION

The BI≥ 107, TBSA≥ 45% burned, and 3rd-degree burns observed on autopsy point to a significantly higher odds that limited CO intoxication occurred, and burns should be considered a concurrent cause of indoor FRD. When less than 40% of TBSA was affected, BI≥ 85 indicated sub-lethal CO poisoning.

Whole mitochondrial genomes assembled from thermally altered forensic bones and teeth

The recovery and analysis of genetic material obtained from thermally altered human bones and teeth are increasingly important to forensic investigations, especially in cases where soft-tissue identification is no longer possible. Although little is known about how these fire-related processes affect DNA degradation over time, next-generation sequencing technology in combination with traditional osteobiographical applications may provide us clues to these questions. In this study, we compare whole mitochondrial genome data generated using two different DNA extraction methods from 27 thermally altered samples obtained from fire victims (Maricopa County, Arizona) . DNA extracts were converted to double-stranded DNA libraries and enriched for whole mitochondrial DNA (mtDNA) using synthetic biotinylated RNA baits, then sequenced on an Illumina MiSeq. We processed the mitochondrial data using an in-house computational pipeline (MitoPipe1.0) composed of ancient DNA and modern genomics applications, then compared the resulting information across the two extraction types and five burn categories. Our analysis shows that DNA fragmentation increases with temperature, but that the acute insult from fire combined with the lack of water is insufficient to produce 5' and 3' terminal deamination characteristic of ancient DNA. Our data also suggest an acute and significant point of DNA degradation between 350 °C and 550 °C, and that the likelihood of generating high quality mtDNA haplogroup calls decreases significantly at temperatures > 550 °C. This research is part of a concerted effort to understand how fire affects our ability to generate genetic profiles suitable for forensic identification purposes.

The effects of elevated temperature on coronary artery dimensions

The interpretation of deaths occurring in fires is often complicated by numerous tissue artefacts. The aim of this experimental study was to see whether coronary arteries exposured to heat may have altered morphology. Two specimens of coronary arteries were taken from each of 10 previously healthy men, who died due to trauma, who had no macroscopic evidence of coronary atherosclerosis - one specimen was immediately fixed in formalin (control group), while the other was exposed to high temperature (70°C for five minutes), and then fixed (experimental group). Morphometric analysis of arterial walls showed significant thickening of about 45 % in tissue samples from the experimental group (control vs. experimental: 604.8μm vs. 879.2μm, p<0.002), with much more prominent thickening of the tunica intima and externa (70 % and>50 %), compared to the tunica media (4%). Another feature was either partial or complete loss of the internal elastic lamina in all of the heated arteries. The results of the current study suggest that the morphology of coronary arteries in cases of fire-related deaths should be carefully interpreted, since the thickness of their wall could be increased not due to underlying disease states, but simply due to heat exposure, which may lead to inaccurate pathological interpretations. This may have considerable medicolegal significance if a deceased driver or pilot is being assessed for liability in an accident.

Contribution of the computed tomography of the anatomical aspects of the sphenoid sinuses to forensic identification

INTRODUCTION

Body identification is the cornerstone of forensic investigation. It can be performed using radiographic techniques, if antemortem images are available. This study was designed to assess the value of visual comparison of the computed tomography (CT) anatomical aspects of the sphenoid sinuses, in forensic individual identification, especially if antemortem dental records, fingerprints or DNA samples are not available.

MATERIAL AND METHODS

This retrospective work took place in a French university hospital. The supervisor of this study randomly selected from the picture archiving and communication system (PACS), 58 patients who underwent one (16 patients) or two (42 patients) head CT in various neurological contexts. To avoid bias, those studies were prepared (anonymized, and all the head structures but the sphenoid sinuses were excluded), and used to constitute two working lists of 50 (42+8) CT studies of the sphenoid sinuses. An anatomical classification system of the sphenoid sinuses anatomical variations was created based on the anatomical and surgical literature. In these two working lists, three blinded readers had to identify, using the anatomical system and subjective visual comparison, 42 pairs of matched studies, and 16 unmatched studies. Readers were blinded from the exact numbers of matching studies.

RESULTS

Each reader correctly identified the 42 pairs of CT with a concordance of 100% [97.5% confidence interval: 91-100%], and the 16 unmatched CT with a concordance of 100% [97.5% confidence interval: 79-100%]. Overall accuracy was 100%.

CONCLUSION

Our study shows that establishing the anatomical concordance of the sphenoid sinuses by visual comparison could be used in personal identification. This easy method, based on a frequently and increasingly prescribed exam, still needs to be assessed on a postmortem cohort.

A study of osseointegrated dental implants following cremation

BACKGROUND

The comparison of dental morphology and restorative work for human identification has been well documented. This case study involved documentation of osseointegrated and clinically restored dental implants following cremation.

METHODS

The mandible and the maxilla were excised from a head containing implants and cremated. The remains were retrieved, digital and radiographic images were taken and elemental analysis undertaken. The brand of implants was identified utilizing web based search engines. A prosthodontist, known to commonly use this implant system, was approached to ascertain possibilities that matched the data given.

RESULTS

Following cremation the implants were identified and a prosthodontist was able to identify the deceased. Two implants in the maxilla had dehiscences on their buccal surfaces, which could not be detected by periapical radiographs.

CONCLUSIONS

Dental implants osseointegrated and restored with a prosthetic superstructure were recognizable following severe incineration. It was possible to trace back the identity of the unknown victim to a prosthodontist. Bone dehiscences discovered in this study highlighted how two-dimensional radiographs may not reveal lack of bone support.

Maximizing postmortem oral-facial data to assist identification following severe incineration

PURPOSE

This paper reviews the literature for methods of maximizing the postmortem oral-facial information available for a comparison to be made for identification following an incident resulting in incineration.

METHOD

A search was initially instigated utilizing PubMed, Scopus, and Google Scholar, with further library searches and correspondences among peers around the world leading to a comprehensive review of the literature.

CONCLUSION

Maximizing postmortem dental evidence in a severe incineration event requires correct recognition and recording of dental data. Odontologists should attend the scene to facilitate this recognition. The information should be documented, photographed, and stabilized before retrieval. Wrapping, padding, and further support of the remains during transportation to the examination mortuary will aid this process. Examination at the mortuary requires further photography, complete charting, and radiographic examination of any dental material available, as well as awareness of other possible medical evidence, to enable identification of the human remains.