Application of three spectrometric methods to total selenium determination in postmortem material in a case of acute selenium compound poisoning

Three spectrometric methods, that is, spectrofluorimetry (SF), atomic absorption spectrometry with electrothermal atomization (ET-AAS), and atomic fluorescence spectrometry with hydride generation (HG-AFS) were used for the determination of total selenium in biological samples taken from postmortem material in a case of acute selenium compound poisoning. The precision of the SF, ET-AAS, and HG-AFS methods (RSD, n=10) was found to be in the ranges of 10.0-15.0, 3.0-6.0 and 1.0-1.5%, respectively, and the detection limit was 10.0, 4.0, and 0.1 μg/L of Se, respectively. In the case of HG-AFS, the analytical procedure takes less time and is less laborious than the other methods considered. The obtained results show the usefulness of the HG-AFS method as a supplementary analytical tool to the SF and ET-AAS methods with respect to the determination of selenium as well as the possibility of using this method as a primary one in forensic toxicology practice.     

Waxing grave about adipocere: soft tissue change in an aquatic context

When postmortem environmental conditions are "just right," according to the "Goldilocks Phenomenon," soft tissues (and associated fatty acids) are converted into and preserved as adipocere. To better understand this conversion process and the development of adipocere three human cadavers were immersed in outside, water-filled pits for over 3 months to observe adipocere formation in an underwater context simulating actual field conditions. Recordings of environmental conditions showed that temperatures were between 21 degrees C and 45 degrees C, a range sufficient for the growth of Clostridium perfringens. Chemical analysis of liquid and tissue samples revealed an increase in palmitic acid and decrease in oleic acid. This study tracked the remarkable gross morphological changes that can occur in human bodies subjected to an aquatic postmortem environment. The results support the "Goldilocks Phenomenon" and substantiate previous findings that the presence of bacteria and water is crucial for adipocere to form.     

Postmortem Skeletal Survey Practice in Pediatric Forensic Autopsies: A National Survey*

Abstract: Recommendations for the evaluation of an unexplained death in infancy include a postmortem skeletal survey (PMSS) to exclude skeletal trauma. Objectives of this study were to assess adherence to these recommendations in forensic autopsies in children equal to or less than 36 months of age, and what factors influence the use or nonuse of the PMSS. We surveyed pathologists who were members of the American Academy of Forensic Sciences. The survey included practice characteristics about where, when, and how PMSS were done. Nearly all respondents (99.6%) indicated they performed PMSS at least some of the time; however, almost a third did not use PMSS for all suspected Sudden Infant Death Syndrome (SIDS), abuse, unsafe sleep, or undetermined causes of death. Despite evidence that “babygrams” are inappropriate in a SIDS workup, 30% of pathologists use them preferentially. Despite SIDS being a diagnosis of exclusion that requires a PMSS, almost 10% of pathologists do not order a PMSS. Future research is necessary to reduce barriers to this important component of the pediatric forensic autopsy.     

Pig-mentation: postmortem iris color change in the eyes of Sus scrofa

Experienced forensic pathologists and examiners may be familiar with the phenomenon of postmortem iris color change; however, only Knight, Simpson's forensic medicine, Arnold, London, 1997; Ref. 1 and Saukko and Knight, Knight's forensic pathology, 3rd ed., Arnold, London, 2004; Ref. 2 have referred to it in the literature, and to date, there have been no published scientific research studies on this taphonomic artifact. A controlled experiment was conducted of postmortem changes to isolated Sus scrofa eyes. The eyes (n = 137) were separated into three groups and each sample was observed for 3-day postmortem at a different temperature. In addition, a Sus scrofa head was obtained to observe postmortem changes of eyes in situ. All isolated blue eyes in the experiment, at room temperature and higher, changed to brown/black within 48 h. The in situ blue eye, at room temperature, turned brown/black within 72 h. If iris color consistently changes postmortem in humans, then this taphonomic artifact must be incorporated into victim identification protocol, including disaster victim identification software, and autopsy reports to prevent inaccurate victim identification and inappropriate exclusion from the identification process.     

尸体血管造影技术的发展和趋势

尸体血管造影技术是一种有效的血管检查手段,对探查尸体血管,尤其是心脏、脑部血管的情况具有重要意义。该技术起源于15世纪,发展于18、19世纪。尤其是在发现X线之后,该技术进入了快速发展阶段,无论是在对比剂、灌注方法,还是在成像方法上都取得了巨大的发展。目前,该技术已被广泛应用于实践中。但该技术仍存在一些瑕疵,首先,对比剂仍无法克服渗透弥散、栓塞血管等问题,最理想的对比剂仍未发现;其次,目前的灌注方法仍无法模拟生理血液流动状态。在＂保全尸＂的宗教和传统观念的指引下,有必要进一步提高目前的造影技术,以满足实践需求。     

死亡人体组织中rRNA亚基的稳定性及影响因素评价

目的探讨人尸体组织中rRNA亚基表达水平的稳定性及影响因素。方法选取3例成人、3例婴幼儿大脑皮质和脾组织,在尸检即刻、48、72、96、120、144、168、192、216、240h,采用实时荧光定量RT-PCR法检测5s、5.8s、18s、28s rRNA的表达水平。结果两个年龄组两种组织中4种rRNA亚基表达量相比较均显示有差异(P0.05)。同种组织比较:脑组织中两个年龄组最后一个时间点与第一时间点4种rRNA亚基的表达量均有差异(P0.05),其他各时间点与第一时间点无显著性差异(P0.05);脾组织中婴幼儿5s rRNA在最后一个时间点,其余3种rRNA亚基最后两个时间点与第一时间点比较有差异(P0.05);成人5s rRNA最后一个时间点,5.8s rRNA亚基最后两个时间与第一时间点比较差异(P0.05),其余两种亚基各时间点与第一时间点相比较均无差异(P0.05)。结论尸体组织中rRNA亚基表达稳定性好,适于作为晚期死亡时间推断的内参基因使用,但需注意指标、组织和年龄段差异性。     

Identifying background microbiomes in an evidence recovery laboratory: A preliminary study

16S rRNA profiling of bacterial communities may have forensic utility in the identification or association of individuals involved with criminal activities. Microbial profiling of evidence may, in the future, be performed within environments currently utilised for human DNA recovery, such as a forensic biology laboratory. It would be important to establish the background microbiome of such an environment to determine the potential presence of human or environmental microbial signatures to assist forensic scientists in the appropriate interpretation of target microbial communities. This study sampled various surfaces of an Evidence Recovery Laboratory (ERL) on three occasions including (a) before a monthly deep-clean, (b) immediately following the deep-clean, and (c) immediately after the laboratory’s use by a single participant for the purposes of routine item examinations. Microbial profiles were also generated for the involved participant and researcher for comparison purposes. Additionally, human nuclear DNA was profiled for each of the samples collected, using standard forensic profiling techniques, to provide a prospective link to the presence or absence of a background microbial signature within the ERL after its use. Taxonomic distributions across ERL samples revealed no consistent signature of any of the items sampled over time, however, major phyla noted within all ERL samples across the three timepoints were consistent with those found in human skin microbiomes. PCoA plots based on the Unweighted Unifrac metric revealed some clustering between participant microbial reference samples and surfaces of the ERL after use, suggesting that despite a lack of direct contact, and adherence to standard operating procedures (SOPs) suitable for human DNA recovery, microbiomes may be deposited into a forensic setting over time. The reference samples collected from the involved participant and researcher generated full STR profiles. Human DNA was observed to varying degrees in samples taken from the ERL across each of the sampling timepoints. There was no correlation observed between samples that contained or did not contain detectable quantities of human nuclear DNA and microbial profile outputs.     

Perimortem or Postmortem Bone Fractures? An Experimental Study of Fracture Patterns in Deer Femora*

The determination of perimortem trauma is important for forensic anthropologists. Characteristics of bone fractures such as sharp edges, presence of fracture lines, the shape of the broken ends, fracture surface morphology, fracture angle on the Z-axis, and butterfly fractures are said to differentiate perimortem from postmortem trauma. A Drop Weight Impact Test Machine was used to break 76 deer femora of various ages since death. The results of this study suggest that the characteristics listed above are unreliable at differentiating a perimortem fracture from a postmortem fracture in a forensic case. There are, however, statistically significant differences between fresh bones broken less than 4 days old and dry bones broken 44 days or 1 year old after death.     

Oral abuse of fentanyl patches (Duragesic): seven case reports

In order to increase the understanding regarding the oral abuse and potential toxicity of fentanyl patches seven cases were identified over a 3-year period where fentanyl, either alone or in combination with other factors, contributed to death following the oral abuse of Duragesic patches. The decedents comprised three females and four males with ages ranging from 20 to 51 years. Postmortem blood fentanyl concentrations were determined in all cases and ranged from 7 to 97 ng/mL. Two deaths were classified as a fentanyl overdose, three deaths were classified as a fentanyl and ethanol overdose, one death was considered a mixed drug intoxication and the remaining death was determined to be a combination of fentanyl and medical causes. These cases represent the largest reported series of deaths following the oral administration of transdermal fentanyl patches and provide detailed information on the potential for the abuse of transdermal Duragesic patches via this route. The postmortem blood fentanyl concentrations detected for each of the decedents demonstrate the potentially fatal blood concentrations that can arise after this relatively rare route of administration.