The Correlation Between Skeletal Weathering and DNA Quality and Quantity*

Abstract: Mitochondrial DNA analysis of skeletal material is invaluable in forensic identification, although results can vary widely among remains. Previous studies have included bones of different ages, burial conditions, and even species. In the research presented, a collection of human remains that lacked major confounders such as burial age, interment style, and gross environmental conditions, while displaying a very broad range of skeletal degradation, were examined for both mitochondrial DNA (mtDNA) quality and quantity. Overall skeletal weathering, individual bone weathering, and bone variety were considered. Neither skeletal nor bone weathering influenced DNA quality or quantity, indicating that factors that degrade bone do not have the same effect on DNA. In contrast, bone variety, regardless of weathering level, was a significant element in DNA amplification success. Taken together, the results indicate that neither skeletal nor individual bone appearance are reliable indicators of subsequent mtDNA typing outcomes, while the type of bone assayed is.     

Age at Death Estimation Using Multislice Computed Tomography Reconstructions of the Posterior Pelvis*

Abstract: Thanks to recent advances, computed tomography is now seen as a tool of great value in the field of physical anthropology. In this study, we focused on the posterior pelvis and the auricular surface and evaluated the accuracy of 3D reconstructions of the auricular surface, using a methodology derived from a previous study by Lovejoy et al. We also looked for trabecular bone criteria expressing age‐related changes. Forty‐six coxal bones were scanned, and scoring of macroscopic criteria showed a good agreement between 3D reconstructions and photographs, especially for transverse organization (k = 0.90). The changes occurring in the posterior part of the sacropubic trabecular bundle were evaluated on CT reconstructions via three new criteria, which exhibited a good intra‐ and inter‐observer agreement (k = 0.77–0.89), and were particularly useful in identifying older subjects. We concluded that these CT‐evaluated trabecular bone criteria are promising and yield useful information about age at death.     

A Preliminary Assessment of the Identification of Saw Marks on Burned Bone*

Abstract: This study assesses the degree of modification to the saw mark characteristics of dismembered skeletal remains when exposed to a controlled outdoor fire of limited duration. The sample consists of 36 adult pig hind limbs which were dismembered fleshed. Six handsaws and six power saws were used, with three limbs dismembered and burned for each of the saw types. Results indicate that fire exposure affects the visibility and identifiability of saw mark striae. With the handsaws, the bow saw, hacksaw, and keyhole saw were consistently recognizable. In the power saw group, the saw marks of the jigsaw, reciprocating saw, and chainsaw remained identifiable. Although the bone ends exhibited thermal alterations, the false starts were well preserved with minimal damage. Given the parameters of this study, it is possible to identify the class of saw based on the diagnostic characteristics present on the cremated bones.     

烧骨的研究现状与展望

本文根据国内外相关文献,对烧骨的宏观、微观形态学特点,烧骨形态特征与各影响因素之间的关系,热致骨折与损伤骨折、条件性骨折的鉴别等方面进行了综述,并对现有研究的局限之处进行了分析,提出改进方向。     

儿童骨骼特征的组织学研究

目的研究儿童骨骼的组织学特征,为儿童骨骼残片的法医学鉴定提供科学依据。方法提取儿童四肢长骨骨片,制作骨骼的组织切片,在显微镜下观察内、外环骨板,骨单位,骨细胞的组织学结构,比较儿童骨骼与动物及成人骨骼的组织学区别。结果儿童骨骼的骨单位形态与成人相似,骨单位间存在大量的内层骨板,与动物的骨组织特征相似。结论根据骨组织学特征,可以确定儿童的骨骼残片。     

Highly efficient and automated extraction of DNA from human remains using a modified EZ1 protocol

Bones and teeth often represent the only sources of DNA available for identifying human remains. DNA in bones and teeth is generally better preserved than that in soft tissues because of the presence of hard connective tissue with a high level of calcium. Because of the extensive mineralisation, the choice of an efficient DNA extraction procedure is important to minimise the sampling of a high level of minerals and to remove polymerase chain reaction (PCR) inhibitors. Some protocols are available for DNA extraction from bones and teeth as part of the Qiagen EZ1 DNA Investigator Kit using the EZ1 Advanced XL automated purification platform. To improve the efficiency of DNA extraction from skeletal remains, the present study focuses on a modification to these already available protocols. In this study, different bones and teeth collected between 1 and 50 years after death were subjected to DNA extraction using the standard EZ1 protocol, a supplementary protocol, and a modified protocol. The modified approach included a decalcification step, whereas the Qiagen protocols worked directly on non-decalcified powder. In all three procedures, 150 mg samples were used for DNA extraction. We evaluated the quantity of DNA recovered from samples, the presence of any PCR inhibitors co-extracted, the level of DNA degradation, the quality of short tandem repeat (STR) profiles, and the reproducibility of the modified procedure. When compared with the other protocols, the modified protocol resulted in the best recovery of DNA that was free of PCR inhibitors. Additionally, the STR profiles were reliable and of high quality. In our opinion, the decalcification step increases DNA recovery by softening tissues, which allows lysis solutions to act more effectively. Furthermore, the use of two lysis solutions and the variation added to the EZ1 purification step allow for DNA recovery with quality and quantity superior to those of the previously available Qiagen-based protocols. These findings may be helpful solutions to the problems commonly encountered when dealing with difficult samples, such as bones and teeth.

Key points

• Bones and teeth often represent the only sources of DNA for identifying human remains.
• The choice of an efficient DNA extraction procedure is important for maximizing DNA recovery and removing PCR inhibitors.
• This study focuses on modifications to the previously available Qiagen-based protocols.
• The modified protocol enabled the best recovery of DNA, and both quality and quantity were superior to those of the previously available Qiagen-based protocols.
• The STR profiles obtained from samples extracted using the modified protocol were reliable and of high quality.

     

补肾填精法对兔骨折后不同时相骨髓间充质干细胞成骨分化的影响

目的 观察补肾填精中药对兔骨折后不同时点骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)分化为成骨细胞的影响。方法 将20只白兔随机分成4组,即正常对照组、骨折模型组、中药治疗组、西药治疗组。分离培养骨折端BMSCs,取P3代BMSCs并向成骨细胞诱导分化,分别采用碱性磷酸酶（alkaline phosphatase, ALP）试剂盒、骨钙素（osteocalcin, OCN）试剂盒检测ALP活性、OCN水平。结果 随着用药时间的延长,各骨折组ALP活性和OCN水平均逐渐增强。在骨折后第14、21天,中药治疗组ALP活性、OCN水平均高于其他3组。结论 补肾填精法可促进兔骨折后不同时点BMSCs向成骨细胞分化。     

“矫筋正骨法”针刀治疗膝骨关节炎临床疗效观察

目的 观察“矫筋正骨法”针刀治疗膝骨关节炎（knee osteoarthritis,KOA）的临床疗效和对步态的影响。方法 纳入KOA患者65例,采用随机数字表法随机分为针刀组和对照组。其中针刀组32例,行“矫筋正骨法”针刀治疗;对照组33例,行常规针刺治疗,分别于治疗前后采用视觉模拟量表（visual analogue scale,VAS）评分、美国特种外科医院（Hospital for Special Surgery,HSS）膝关节评分及步态分析的方法进行疗效评估。结果 与治疗前比较,治疗后两组VAS显著降低（P<0.05）,HSS评分中的疼痛、功能、活动度评分和总分均显著升高（P<0.05）,治疗后针刀组屈曲畸形评分也较治疗前显著升高（P<0.05）,治疗后针刀组和对照组步频、步速、步长均显著改善（P<0.05）;与对照组比较,针刀组治疗后VAS显著降低（P<0.05）,HSS评分中疼痛、功能、活动度评分和总分均显著升高（P<0.05）,步频显著改善（P<0.05）;两组患者综合疗效比较,针刀组显著优于对照组（P<0.05）。结论 “矫筋正骨法”针刀可以显著减轻KOA患者的疼痛症状,并且可以使患者的关节功能、活动度以及步频同步得到改善,体现了KOA治疗中“筋骨并重、标本兼治”的思想。     

六味地黄汤通过树突状细胞Notch信号通路调节T细胞分化干预自身免疫性脑脊髓炎

目的 通过观察树突状细胞(dendritic cells,DCs)Notch信号通路对CD4+T细胞分化的影响,探究六味地黄汤干预实验性自身免疫性脑脊髓炎(experimental autoimmune encephalomyeli-tis,EAE)的机制.方法 采用主动免疫法诱导2D2小鼠EAE模型,采用磁珠分选收集...     

李业甫筋骨并举整脊法治疗颈性眩晕临床疗效观察

目的 观察李业甫筋骨并举整脊法治疗颈性眩晕的临床疗效.方法 将80例颈性眩晕患者按照随机数字表法分为对照组和观察组,每组40例.对照组患者采用常规推拿治疗,观察组患者采用常规推拿结合李业甫筋骨并举整脊法治疗.比较两组患者临床疗效,治疗前后颈性眩晕症状与功能评分、眩晕残障程度评定量表(dizziness handicap inventory,DHI)评分及椎-基底动脉血流速度.结果 两组患者临床疗效比较,差异有统计学意义(P<0.05),观察组的治疗效果优于对照组.两组治疗后颈性眩晕症状与功能评分均显著升高,DHI评分均显著降低(P<0.05),且观察组改善程度显著优于对照组(P<0.05).两组治疗后左侧椎动脉、右侧椎动脉、基底动脉平均血流速度均有所增加(P<0.05),且观察组改善程度优于对照组(P<0.05).结论 李业甫筋骨并举整脊法可以有效调节椎-基底动脉血流速度以减轻患者的眩晕症状.