Forensic scatology: preliminary experimental study of the preparation and potential for identification of captive carnivore scat

Carnivore scats recovered from animal attack and/or scavenging contexts frequently contain forensic evidence such as human bone fragments. Forensic cases with carnivore involvement are increasingly prevalent, necessitating a methodology for the recovery and analysis of scat evidence. This study proposes a method for the safe preparation of carnivore scat, recovery of bone inclusions, and quantification and comparison of scat variables. Fourteen scats (lion, jaguar, lynx, wolf, and coyote) were prepared with sodium-acetate-formalin fixative; analytical variables included carnivore individual, species, body size, and taxonomic family. Scat variables, particularly bone fragment inclusions, were found to vary among carnivore individuals, families, species, and sizes. The methods in this study facilitate safe scat processing, the complete recovery of digested evidence, and the preliminary identification of involved animals. This research demonstrates that scat collected from forensic contexts can yield valuable information concerning both the victim and the carnivore involved.     

维生素D受体基因多态性研究进展

维生素D受体(vitaminDreceptor,VDR)基因多态性可能与骨密度、骨质疏松、身高相关。本文作者就近年国内外所开展的VDR基因4个单核苷酸多态性(singlenucleotidepolymorphism,SNP)位点FokI、BsmI、ApaI、TaqI与骨密度、骨质疏松、身高关联性研究进行综述,发现各国的研究结果虽不尽相同,但VDR基因多态性在遗传学、临床内分泌代谢,尤其在法医学领域对身高的研究中,有重要的应用价值。     

烧骨残片种属鉴定的研究

为了找出常见动物骨骼焚烧残片的种属鉴定方法,笔者对猪、羊,股骨及肱骨的断端,猪、羊、牛颅骨的残片(额顶部),焚烧后进行了观察及测量,并与人类股骨、肱骨及焚烧的颅骨残片进行了比较.结果发现,长骨滋养孔的位置,骨干骨壁厚度,以及颅骨厚度,颅缝形态及内板表面特征等方面,是鉴定骨骼残片种属的有价值的特征.根据对常见动物长骨及颅骨残片的现察及研究,提出了骨骼残片种属鉴定的方法.     

Resolving Reflection and Resolution in 3D Imaging of Fresh Bone

Structured light scanning is a noninvasive, accurate, and cost-effective 3D imaging technique, but due to reflection issues is yet to be utilized for tool mark analysis on fresh bone. During imaging, reflection from shiny surfaces, such as greasy bone, disrupts image formation. This study tested the David SLS-1 scanner's ability to image saw marks and explored six strategies to reduce reflection by [1] dulling the surface or [2] altering the projected light. The surface was dulled by freezing, talcum powder, dulling spray, or compressed air. The projected light was altered with a diffuser or limited to single pattern-coded. Results demonstrated that the resolution was insufficient for capturing minute details of striae. All six tests failed to reduce reflection sufficiently to produce complete images, but projecting vertical pattern-coded light showed the most promise. Future research is required concentrating on enhancing resolution and exploring the role of pattern-coded light in reducing reflection.     

Differentiation of Antemortem and Postmortem Appendicular Fractures Using Magnetic Resonance Imaging Signal Intensity Changes in Bone and Soft Tissues,

Intraosseous T1-weighted (T1W) and short-tau inversion recovery (STIR) magnetic resonance imaging (MRI) signal intensity changes—so-called bone marrow edema—may be able to differentiate antemortem and postmortem fractures in human forensic imaging. The primary objective of this study was to investigate this hypothesis using an animal model. Three juvenile Landrace pigs were anesthetized and underwent MRI of both tibiae and both radii using a 1.5 T magnet. T1W, T2-weighted (T2W), STIR, and T2* sequences were included. Antemortem fractures were induced in both tibiae and postmortem fractures in both radii, and MRI was repeated. Two board-certified radiologists blinded to fracture group jointly evaluated the images for intraosseous and soft tissue signal intensity changes. Sensitivity (Se) and specificity (Sp) in identifying antemortem fractures were calculated based on intraosseous, soft tissue, and combined intraosseous and soft tissue signal intensity changes. Intraosseous and soft tissue signal intensity changes, when present, were hyperintense in all sequences. Intraosseous hyperintensity in T1W and T2W sequences yielded Sp of 100% for antemortem fractures. Regardless of sequence, soft tissue hyperintensity was comparatively more sensitive than intraosseous hyperintensity. Sensitivity for each sequence could be maximized by assessment of soft tissue and intraosseous hyperintense signals together; for the T1W sequence, such assessment optimized diagnostic utility yielding a Se of 100% and Sp of 83%. In summary, MRI—particularly the T1W sequence—can differentiate antemortem and postmortem fractures and may be a useful adjunct to the forensic analyses of fractures.     

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.     

Ossification of laryngeal structures as indicators of age

As the role of forensic anthropologists expands to the medical examiner setting, their expertise is being applied beyond the traditional dry skeletal material. In such scenarios radiographic techniques can be applied when maceration is not appropriate. This study explores the use of radiographic analysis of laryngeal structures for age-at-death determination. Isolated human laryngeal structures (n = 104) from individuals between the ages of 15 and 89 were removed at autopsy and radiographically examined. The cricoid and individual regions of the thyroid cartilage were scored according to degree of ossification, and the relationship between age and degree of ossification statistically examined. A previously published study on age-determination from thyroid ossification by Cerny was assessed for accuracy. The results of the study indicate that although a consistent sequence in the ossification of laryngeal structures exists, variations in timing does not permit narrow age range estimates. Consequently the method presented by Cerny is inaccurate and should not be used in the forensic setting.     

14岁青少年骨发育的变化趋势

目的描述当前我国14岁青少年手腕骨发育特征,并初步评估14岁的青少年骨发育的变化趋势。方法以湖南娄底地区14岁青少年为对象(男53人,女56人),拍摄左手腕部X线片,参照顾氏图谱法描述各选定观察部位并分析发育特征,将统计结果与顾氏图谱法14岁骨龄标准进行比较分析。结果与顾氏法相比,男生组桡骨远端、第1掌骨近端和近节第4指骨骨骺发育程度较高,而女生组桡骨远端、第2～5掌骨、第1～5近节指骨和第2～5中节指骨骨骺发育程度较高。结论当前我国14岁青少年骨发育存在提前趋势,在女生组尤为显著。14岁是刑事责任年龄点之一,法医推断该年龄时应注意该特征对推断结果的影响。     

A Concentrated Hydrochloric Acid-based Method for Complete Recovery of DNA from Bone

The successful extraction of DNA from historical or ancient animal bone is important for the analysis of discriminating genetic markers. Methods used currently rely on the digestion of bone with EDTA and proteinase K, followed by purification with phenol/chloroform and silica bed binding. We have developed a simple concentrated hydrochloric acid-based method that precludes the use of phenol/chloroform purification and can lead to a several-fold increase in DNA yield when compared to other commonly used methods. Concentrated hydrochloric acid was shown to dissolve most of the undigested bone and allowed the efficient recovery of DNA fragments <100 bases in length. This method should prove useful for the recovery of DNAs from highly degraded animal bone, such as that found in historical or ancient samples.     

不同染色组织切片及不同组织固定方法对检测STR基因座的影响

目的探讨不同染色组织切片及不同组织固定方法对DNA检验的影响。方法采用Chelex100法及浓缩纯化方法提取DNA,PCR扩增后310型遗传分析仪检测。结果福尔马林固定4天以内或70%乙醇、无水乙醇分别固定1年及15年的HE染色切片可以检见Amel及9个STR基因座。PTAH等5种特殊染色未能检出相应基因座DNA谱带。结论70%乙醇或无水乙醇固定组织,石腊包埋组织及HE染色切片可以作为DNA?STR检验鉴定的样本材料。