Time- and Temperature-Dependent Changes in Cytochrome c Oxidase Activity and Cyanide Concentration in Excised Mice Organs and Mice Cadavers

Postmortem stability of cyanide biomarkers is often disputed. We assessed the time and temperature-dependent changes in cytochrome c oxidase (CCO) activity and cyanide concentration in various organs of mice succumbing to cyanide. Immediately after death, excised mice organs and mice cadavers were stored at room temperature (35°C ± 5°C) or in frozen storage (−20°C ± 2°C). At various times after death, CCO activity and cyanide concentrations were measured in excised mice organs or organs removed from mice cadavers. The study revealed that (i) measuring both the biomarkers in mice cadavers was more reliable compared to excised mice organs, (ii) measuring temporal CCO activity and cyanide concentration in vital organs from mice cadavers (room temperature) was reliable up to 24 h, and (iii) CCO activity in the brain and lungs and cyanide concentration in organs from mice cadavers (frozen) were measurable beyond 21 days. This study will be helpful in postmortem determination of cyanide poisoning.     

大鼠皮肤挫伤后NF-κB mRNA表达与损伤时间关系

目的应用实时定量PCR技术检测大鼠皮肤挫伤后NF-κB mRNA时序性表达规律，分析其与损伤时间的关系。方法制备大鼠皮肤挫伤模型，于伤后0．5，1，6，12，18，24，30h取材，一步法提取总RNA，检测其完整性和浓度，按照0．4μg总RNA量逆转录合成第一链cDNA，以rlp32为内参基因进行荧光定量检测，采用△Ct法比较其与正常皮肤组织NF-κB mRNA表达的倍数关系。结果皮肤挫伤组织中NF-κB mRNA伤后0．5h表达显著增强（P〈0．05），6h出现高峰，12h降至正常水平，随后略有回升。结论大鼠皮肤挫伤组织NF-κB mRNA的表达，随着损伤经过时间的延长呈规律性变化。     

A test of the auricular surface aging technique

A recently developed technique used in the estimation of age at death is based upon the metamorphosis of the auricular surface of the ilium. This technique was designed to be used in seriation to estimate the age distribution of a skeletal sample. However, the technique has also been used in forensic science cases, which must be analyzed on a case-by-case basis. The present study examines the use of the auricular surface technique as the single aging factor. Two hypotheses are tested using a sample of 189 individuals drawn from the Terry Collection, housed at the Smithsonian Institution. The hypotheses are (1) is the method equally applicable across race and sex, and (2) how well does the method perform as the single aging factor? The results indicate that the amount of degenerative change in the auricular surface is not dependent upon race or sex in any given age category. However, the rate of degenerative change is too variable to be used as a single criterion for the estimation of age; the range of estimation error is simply too large for forensic science purposes.     

大鼠骨骼肌挫伤后Fzd2表达与损伤时间的关系

目的检测大鼠骨骼肌挫伤后卷曲受体蛋白2(frizzled-2,Fzd2)mRNA及其蛋白表达量与损伤时间的关系,探讨其是否可以作为损伤时间推断的指标。方法利用RT-qPCR和Western印迹法检测正常对照组及损伤后4~48 h每4 h大鼠骨骼肌中Fzd2 mRNA和蛋白水平的表达量。结果 Fzd2 mRNA在损伤后24 h、36 h、40 h相对表达量增高,24 h组表达量达正常对照组的两倍(P0.05);而Fzd2蛋白在损伤后相对表达量变化不明显(P0.05)。结论大鼠骨骼肌损伤后Fzd2 mRNA在一定时间内的表达变化情况可以作为多指标联合推断损伤时间的依据。     

Genotypic Polymorphisms of Hepatitis B Virus Provide Useful Information for Estimating Geographical Origin or Place of Long‐term Residence of Unidentified Cadavers

Increasing numbers of unidentified cadavers are a major problem. We have developed a new method for providing identification information that can determine the geographical origin or place of long‐term residence of unidentified cadavers based on genotypic polymorphisms of hepatitis B virus (HBV) known to correlate with their geographical distribution. PCR of serum samples detected HBV DNA from 4 (3.9%) of 102 randomly selected Japanese forensic cadavers. Multiplex PCR did not detect multiple HBV genotypes from any single cadaver, confirming the absence of coinfection. Phylogenetic tree analysis based on a 485‐bp mutant region of the HBV S gene successfully classified the HBV genotypes into A to J. Among 10 HBV‐infected cadavers, 8 had genotype Ce/C2, a genotype prevalent in East Asia, and 2 had genotype Bj/B1, a Japanese‐specific genotype. HBV genotypic polymorphisms correlate with the geographical distribution of the virus and thus provide important information for identifying unidentified cadavers infected with HBV.     

DNA甲基化及其与个体年龄相关性研究

近年来表观遗传学研究发现,基因组DNA甲基化总体水平随年龄增加而降低,同时部分位点的甲基化水平却随年龄增加而升高。本文重点介绍了DNA甲基化与年龄的相关性及其在年龄推断方面的研究进展,旨在为法医学个体年龄推断的研究提供一种新的思路。     

Artificial radiocarbon as an indicator of recent origin of organic remains in forensic cases.

From 1950 to 1963 atmospheric testing of thermonuclear devices produced elevated levels of artificial carbon-14 in the atmosphere. Terrestrial organic material from that time period displays carbon-14 activity nearly twice the pre-1950 levels. Measurement of the carbon-14 activity within organic specimens from forensic cases can reveal if the material dates before or after about 1955. Such information can prove important in some cases in determining if the material is sufficiently recent to be of forensic concern. Application of this technique to an unidentified human skeleton from the American southwest is discussed.     

Use of the cranial base in the identification of fire victims

Techniques exist for using the cranial base to estimate the race and sex of skeletalized individuals in forensic science cases. The applicability of these techniques to remains of fire victims has been uncertain because of possible cranial-base shrinkage that may result from burning. To determine the amount of shrinkage resulting from low-temperature burning (less than 800 degrees C), the cranial bases of eight dissecting room cadavers were measured, the bones then burned, and the cranial fragments remeasured. The wet-bone measurements were compared to the burned-bone measurements, and the percentage of shrinkage was calculated. The average change from wet to burned bone is less than 1.00%, a figure in agreement with other published studies. Since a change of 1.00% is less than intraobserver error, it is argued that low-temperature burning--such as an average house fire--does not significantly impair the accuracy of the identification techniques. Therefore, the techniques should be applicable to many fire victims.     

A review of the methodological aspects of aspartic acid racemization analysis for use in forensic science.

Accurate age determination of adult cadavers and human remains is a key requirement in forensic practice. The current morphological methods lack accuracy and precision, require specialist training and are costly. The use of aspartic acid racemization (AAR) in human dentine provides a simple, cost-effective solution and the method can achieve accuracies of +/- 3 years at best. Currently, there are differences in AAR methodology between laboratories which produce different results on the rate of racemization in teeth. These inconsistencies must be resolved if the technique is to be successfully applied to age determinations in forensic cases. This paper reviews the differences in protocol which have been used, discusses how each method will affect the results obtained from AAR analysis and gives recommendations for optimization of the methological protocol as a first step towards international standardization.     

Determining the human origin of fragments of burnt bone: a comparative study of histological, immunological and DNA techniques.

In situations where badly burnt fragments of bone are found, identification of their human or non-human origin may be impossible by gross morphology alone and other techniques have to be employed. In order to determine whether histological methods were redundant and should be superseded by biomolecular analyses, small fragments of artificially burnt bone (human and non-human) were examined by quantitative and standard light microscopy, and the findings compared with newer biomolecular analyses based on identifying specific human albumin by ELISA and amplifying human mitochondrial DNA by PCR. For quantitative microscopy, reference data were first created using burnt bones from 15 human and 20 common domestic and farm animals. Measured osteon and Haversian canal parameters were analysed using multivariate statistical methods. Highly significant differences were found between values for human and non-human bone, and a canonical discriminant function equation was derived, giving a predicted correct classification of 79%. For the main study, samples of cortical bone were taken from three fresh cadavers, six human skeletons and ten freshly slaughtered animals and burnt by exposure to temperatures ranging from 800 to 1200 degrees C; charred fragments of human cortical bone from two forensic cases were also tested. Quantitative microscopy and canonical discriminant function gave the correct origin of every sample. Standard microscopy falsely assigned burnt bone from one human skeleton and one forensic case to a non-human source, but otherwise gave correct results. Human albumin was identified in five individuals, including one of the forensic cases, but mitochondrial DNA could not be amplified from any of the human bone. No false positive test results were seen with either biomolecular method; and human albumin and mitochondrial DNA were correctly identified in all unburnt control specimens. It was concluded that histological methods were not redundant and that quantitative microscopy provided an accurate and consistent means of determining the human or non-human origin of burnt bone and was more reliable than standard microscopy or the newer immunological and DNA techniques tested here.     

A multiplex analysis of RNA expression during injury healing in human dermal injuries for injury age estimation

The determination of the timing of a human dermal injury is important in forensic work as it provides valuable information that helps evaluate the relationship between the injury and the crime, and aids in the reconstruction of a crime. In spite of its importance, currently there are no routinely used methods for the accurate estimation of human dermal injury age. In this study, we developed a RNA based multiplex assay to simultaneously investigate the mRNA expression of chymase 1 (CMA1), collagen type III alpha I (COL3A1), dual specificity phosphate 1 (DUSP1), interleukin 1beta (IL1β), interleukin 2 (IL2), interleukin 6 (IL6), interleukin 7 (IL7), tumor necrosis factor alpha (TNFα) and vascular endothelial growth factor A (VEGFA) in human dermal injuries to identify and evaluate their suitability for human dermal injury age estimation. The mRNA expression patterns observed for CMA1, DUSP1, IL1β, IL7, TNFα and VEGFA suggest they have potential to estimate human dermal injury age, especially during the early stages (days) of injury healing.     

ERCC1和XPF基因在法医学年龄推断中的初步研究

目的探讨ERCC1和XPF基因mRNA及蛋白在不同年龄段健康汉族人群中的表达情况,分析其mRNA和蛋白表达量与年龄之间的相关性,以期为法医学年龄推断提供新的分子生物学指标。方法收集150例不同年龄段健康汉族人群外周血样,梯度离心法分离血浆,Trizol法提取外周血单个核细胞(PBMCs)总RNA;实时荧光定量PCR检测ERCC1和XPF基因mRNA在PBMCs的相对表达量;酶联免疫吸附试验检测ERCC1和XPF蛋白在血浆中的表达量。结果 ERCC1和XPF基因mRNA在不同性别PBMCs的相对表达量均无统计差异(P0.05)。ERCC1和XPF基因mRNA相对表达量在不同年龄段有统计学差异(P0.05),且不同年龄段组间比较亦均有统计学差异(P0.05)。回归分析显示ERCC1和XPF基因mRNA相对表达量与年龄呈负相关,其相关系数(r)分别为-0.578和-0.844;以年龄为自变量(x),以mRNA相对表达量为因变量(Y),其拟合曲线分别为Y=3.3E-5x~2-0.0261x+1.9175(R~2=0.3244,P0.01)、Y=0.0003x~2-0.0459x+2.0439(R~2=0.729,P0.01)。血浆中ERCC1和XPF蛋白表达量在不同年龄段及性别间均无统计差异(P0.05)。结论 ERCC1和XPF基因mRNA在PBMCs的相对表达量随年龄增加而下降,其血浆中蛋白表达与年龄无关,为建立ERCC1和XPF基因与年龄之间的数学模型提供理论学依据。     

A Bayesian approach to estimate skeletal age-at-death utilizing dental wear

In the forensic context, teeth are often recovered in mass disasters, armed conflicts, and mass graves associated with human rights violations. Therefore, for victim identification, techniques utilizing the dentition to estimate the first parameters of identity (e.g., age) can be critical. This analysis was undertaken to apply a Bayesian statistical method, transition analysis, based on the Gompertz-Makeham (GM) hazard model, to estimate individual ages-at-death for Balkan populations utilizing dental wear. Dental wear phases were scored following Smith's eight-phase ordinal scoring method and chart. To estimate age, probability density functions for the posterior distributions of age for each tooth phase are calculated. Transition analysis was utilized to generate a mean age-of-transition from one dental wear phase to the next. The age estimates are based on the calculated age distribution from the GM hazard analysis and the ages-of-transition. To estimate the age-at-death for an individual, the highest posterior density region for each phase is calculated. By using a Bayesian statistical approach to estimate age, the population's age distribution is taken into account. Therefore, the age estimates are reliable for the Balkan populations, regardless of population or sex differences. The results showed that a vast amount of interpersonal variation in dental wear exists within the current sample and that this method may be most useful for classifying unknown individuals into broad age cohorts rather than small age ranges.     

A microscopic comparison of fresh and burned bone.

Examination of the microstructure of human bone is useful in estimating age at death in forensic science cases. This technique has been tested and is well accepted, however samples of burned bone may complicate analysis because of possible changes in the microstructure occurring during the burning process. In a comparison of fresh and burned ground thin sections taken from midshaft femorae of eight dissecting-room cadavers of known age and sex, this study finds significant shrinkage of microstructural elements through the burning process. These results are compared to previous work on the subject, which found the microstructural elements to increase through the burning process.     

Recommendations for consistent treatment of length variants in the human mitochondrial DNA control region

Human mitochondrial DNA (mtDNA) analysis is a valuable forensic tool, useful in cases where the amount of extracted DNA is low or highly degraded. Population databases are used to determine the relative rarity of a particular profile obtained in a forensic case. Rather than full DNA sequence information, sequence profiles are compared to a reference sequence, and the differences from the reference are recorded in forensic databases. A standard method is proposed for characterizing length variants, and examples are described using actual human control region mtDNA profiles. Consistency in alignment and nomenclature avoids inadvertently describing two sequences as different when in fact they are the same.     

Age determination of an unknown body in early adulthood

The authors report on the estimation of the age of an unidentified deceased adolescent in connection with the body's identification. A physical examination by a forensic physician and an examination by a forensic dentist, including determination of the dental status and an X-ray of the teeth were used to estimate the age. In addition, an X-ray of the left hand as well as an X-ray and MRT scan of the clavicles were carried out by forensic radiologists. Combining the results of the individual examinations, the age of the deceased was estimated to range between 18 and 21 years. In the course of the police investigation it was found out that the deceased was 20 years and 7 months old. This has led to the conclusion that combined use of methods allows the age even of adolescents to be determined with relatively high accuracy and a minimum of time and effort.     

Cutaneous (tPA) and Skeletal (TnI) mRNA as Markers of Aging in Contused Wound

Wound age estimation is one of the most important forensic aspects. Troponin I (TnI) and many cytokines, for example, tissue plasminogen activator (tPA), are involved in wound inflammation and healing. Skeletal (TnI) and cutaneous (tPA) mRNA was detected using real‐time PCR in 25 female albino rats. They were divided into 5 groups: control and 4 injured groups. Injured groups were sacrificed 1, 6, 24, and 30 h after inflicting contused wound. The expression levels of cutaneous (tPA) were decreased significantly at 1, 6, and 30 h after contusion (71.7%, 30.7 and 16.9%), while the expression levels of skeletal (TnI) were increased significantly at 1 and 6 h post‐traumatic, then they gradually decreased until reaching normal levels at 24 h and assumed significantly lower levels at 30 h postcontusion. These results suggested that the determination of cutaneous (tPA) and skeletal (TnI) mRNA levels was useful for wound age estimation.     

Current practices by forensic anthropologists in adult skeletal age estimation

When determining an age estimate from adult skeletal remains, forensic anthropologists face a series of methodological choices. These decisions, such as which skeletal region to evaluate, which methods to apply, what statistical information to use, and how to combine information from multiple methods, ultimately impacts the final reported age estimate. In this study, a questionnaire was administered to 145 forensic anthropologists, documenting current trends in adult age at death estimation procedures used throughout the field. Results indicate that the Suchey-Brooks pubic symphysis method (1990) remains the most highly favored aging technique, with cranial sutures and dental wear being the least preferred, regardless of experience. The majority of respondents stated that they vary their skeletal age estimate process case-by-case and ultimately present to officials both a narrow and broad possible age range. Overall, respondents displayed a very high degree of variation in how they generate their age estimates, and indicated that experience and expertise play a large role in skeletal age estimates.