Forensic mitochondrial DNA analysis of 116 casework skeletal samples

Between February 1999 and May 2005, 116 DNA extractions were completed on skeletal remains from routine casework. Overall, at least a partial mitochondrial DNA (mtDNA) profile was obtained on 83.6% of samples. Skeletal remains fell into two general categories: (1) samples for body identifications submitted by law enforcement and (2) samples submitted to answer historical or family identity questions. Body identification cases were more likely to yield full mtDNA profiles, whereas historical cases were more likely to result in partial profiles. Overall, the ability to obtain a full or partial profile primarily reflects the difference in the average age and condition of the samples in these two categories and thus, difference in the quantity and quality of the DNA. Cremated remains were uniformly unsuccessful, whereas infant/fetal remains were uniformly successful. Heteroplasmy in skeletal remains was observed at a rate similar to that in hair ( approximately 10%). For body identification cases, skeletal remains had the same mtDNA profile as the accompanying reference sample in 50% of cases.     

基于X线的活体骨骼年龄评定方法及其他技术

国内外通常利用X线片观察骨骼继发性骨化中心的出现和骨骺闭合程度的影像学特征来推断年龄。其中较常用的方法有计数法、计测法、图谱法、评分法及计算机辅助评定骨龄法等。目前国外普遍采用TW评分法。国内也有该评分法的应用报道。主要应用于体育和儿科临床实践中。法医临床学实践中常用六大关节判别方程法推断骨龄和活体年龄推断。其他还有利用牙齿内天冬氨酸的消旋化、骨密度检测以及端粒末端DNA片段长度的变化等年龄推断方法。     

X线片的骨骼年龄判定

目前,对儿童青少年骨骼年龄评价以手腕部及膝部较好,方法也较多,但主观性强,随机误差大。随着计算机图像识别及智能化技术的应用,将使得骨骼年龄评价更为客观、准确。对于成年人X线片骨龄推断,以胸骨、耻骨及锁骨等方法具有一定的应用价值,尚需更广泛的方法学研究以增加推断年龄的方法及准确性。本文介绍了X线片的骨骼年龄判定方法的现状及研究进展。     

日粮中维生素D3含量对笼养蛋鸡骨矿含量及骨显微结构的影响

将 175只 10周龄伊莎蛋鸡随机分为A、B、C、D、E共 5组 ,分别在每千克饲料中添加维生素D3(VD3) 0、10 0、2 0 0、5 0 0和 10 0 0IU ,试验期 10周。试验期间每隔 2周测定骨矿含量。试验开始及结束时杀鸡取胫骨 ,进行组织学检查。试验结束时 ,A、B、C、D、E组骨矿总平均值分别为0 .6 6 8g/cm2 ± 0 .0 82g/cm2 、0 .6 79g/cm2 ± 0 .10 2g/cm2 、0 .6 92g/cm2 ± 0 .10 3g/cm2 和 0 .6 6 8g/cm2 ± 0 .0 81g/cm2 、0 .6 47g/cm2 ± 0 .0 79g/cm2 。C组骨矿含量显著高于A、D、E组 (P <0 .0 5 )。骨组织学检查亦显示 ,试验开始时 ,青年蛋鸡皮质骨、骨小梁正常 ;试验结束时 ,低VD3组和高VD3组皮质骨都出现了不同程度吸收腔增多的现象 ,且严重程度与VD3缺乏或过量程度呈正相关性。试验结果表明 ,青年蛋鸡日粮中添加适宜剂量的VD3,可增加骨量 ,维持良好的骨结构。     

Microscopic Residues of Bone from Dissolving Human Remains in Acids

Dissolving bodies is a current method of disposing of human remains and has been practiced throughout the years. During the last decade in the Netherlands, two cases have emerged in which human remains were treated with acid. In the first case, the remains of a cremated body were treated with hydrofluoric acid. In the second case, two complete bodies were dissolved in a mixture of hydrochloric and sulfuric acid. In both cases, a great variety of evidence was collected at the scene of crime, part of which was embedded in resin, polished, and investigated using SEM/EDX. Apart from macroscopic findings like residual bone and artificial teeth, in both cases, distinct microscopic residues of bone were found as follows: (partly) digested bone, thin‐walled structures, and recrystallized calcium phosphate. Although some may believe it is possible to dissolve a body in acid completely, at least some of these microscopic residues will always be found.     

Chromatic Variation of Soot Soiling: A Possible Marker for Gunshot Wounds in Burnt Bone

Soot soiling is a crucial forensic parameter around gunshot lesions. Carbonization, however, can severely alter human tissues and mimic such clues. This study aims at evaluating the survival of soot soiling even after carbonization in bone. A total of 36 bovine ribs (half fleshed and half defleshed) were shot with two types of bullet (both 9‐mm; full metal‐jacketed and unjacketed) with a near‐contact range. With unjacketed bullets, the shot left in every case a clear, black, and roughly round soot stain around the entrance wound, whereas full metal‐jacketed bullets left no signs of soot. Every specimen then underwent calcination in an oven at 800°C. The analysis of the charred samples clearly showed the survival of the soot soiling in both fleshed and bony samples, with a clear correspondence with the former position, but with a different color (yellow). Thus, soot soiling may survive, although with a different color, even after charring.     

Rapid Localization of Bone Fragments on Surfaces using Back‐Projection and Hyperspectral Imaging

Manual localization of bone fragments on the ground or on complex surfaces in relation to accidents or criminal activity may be time‐consuming and challenging. It is here investigated whether combining a near‐infrared hyperspectral camera and chemometric modeling with false color back‐projection can be used for rapid localization of bone fragments. The approach is noninvasive and highlights the spatial distribution of various compounds/properties to facilitate manual inspection of surfaces. Discriminant partial least squares regression is used to classify between bone and nonbone spectra from the hyperspectral camera. A predictive model (>95% prediction ability) is constructed from raw chicken bones mixed with stone, sand, leaves, moss, and wood. The model uses features in the near‐infrared spectrum which may be selective for bones in general and is able to identify a wide variety of bones from different animals and contexts, including aged and weathered bone.     

运用PCR技术对人骨组织和牙齿进行性别鉴定的应用研究

为了解决刑事案件中利用人骨组织和牙齿进行性别鉴定的问题，我们通过骨骼和牙齿中ＤＮＡ的提取床用Ｙ染色体特异ＤＮＭ列引物扩增Ｙ染色体的ＤＹＺＩ和ＳＲＹ基因序列．结果：１．骨组织中ＤＮＡ的提取可在１小时内完成；牙齿中ＤＮＡ的提取可在４小时内完成；２．牙齿中的ＤＮＡ保存的完好性大于骨组织；４．煮沸过的骨组织中的ＤＮＡ降解严重，无法用于实验．     

The effect of weight on the femur: a cross-sectional analysis

This study assessed whether obesity significantly affects femoral shape. Femora of 121 white men were divided into two weight classes based on body mass index (BMI) of the deceased. Five external anteroposterior (AP) and mediolateral (ML) measurements were taken at consistent percentages of diaphyseal length. These were then subject to statistical tests. After controlling for age, multivariate statistics show a significant (p<0.05) effect of BMI on the femur, with the greatest significance in ML measurements. T-tests confirm these dimensions are significantly larger in the overweight (p<0.05). The effect of BMI on size-transformed and shape-transformed variables was also evaluated, with ANOVA results showing a significant BMI effect on ML size (p<0.05), but not shape. Significant size-transformed ML variables were then subject to discriminate function analyses with a cross-validation correction. Results show a correct classification rate of 88% in normal weight and 77% in overweight individuals.