Quantification of Methamphetamine in Mouse Thighbones Buried in Soil

Bone samples are used for analysis of drugs in decomposed or skeletonized bodies. Toxicological analyses of buried bones are important for determining the causes and circumstances of death. In this study, methamphetamine and amphetamine concentrations in heart blood, thigh muscles, and thighbones were analyzed using solid‐phase extraction with liquid chromatography–tandem mass spectrometry. Methamphetamine concentrations in heart blood, thigh muscle, and thighbone ranged from 0.041 to 0.873 μg/mL, 0.649 to 2.623 μg/g, and 56.543 to 643.371 μg/g, respectively. Thighbone concentrations were significantly higher than those in heart blood or thigh muscles were. Methamphetamine concentrations in buried thighbone (4.010–45.785 μg/g) were significantly lower than those of unburied thighbones were (56.543–643.371 μg/g). Methamphetamine and amphetamine were detected in thighbones buried for 7–180 days. These findings indicate that the methamphetamine concentrations in bone are higher and decrease after burial in soil.     

20723例亲子鉴定中19个STR基因座的突变分析

目的观察并分析肯定亲权关系的案件,探索STR基因座的突变规律。方法采用Goldeneye 20A试剂盒对20723例肯定亲权关系的案件筛选等位基因突变事件,统计各基因座的突变率和突变等位基因的来源、片段大小、突变步数及重复单位的增加或减少情况,分析突变相关因素的特点。结果 19个STR基因座共发现548例突变,观察到557个突变事件,基因座的突变率为0.07‰~2.23‰。父系突变与母系突变的比例为3.06∶1。突变以一步突变为主,增加与减少重复单位的情况相当;二步以上(含二步)突变更易出现重复单位减少。突变主要发生于中等位基因,重复单位增减比例相当,长等位基因突变中重复单位减少显著多于增加。父系突变出现重复单位增加与减少的比例相当,母系突变重复单位减少较增加多见。结论各基因座的突变率差异具有统计学意义,当出现1~2个基因座不符合遗传规律时,应当加测其他检测系统,并结合突变基因座的信息计算PI值,以进一步明确鉴定意见。     

Fatal acute intracranial injury, subdural hematoma, and retinal hemorrhages caused by stairway fall

We describe an infant with an acute subdural hematoma, a fatal head injury, and severe hemorrhagic retinopathy caused by a stairway fall. His cerebral and ocular findings are considered diagnostic of abusive head trauma by many authors. Our literature search of serious injuries or fatalities from stairway or low-height falls involving young children yielded 19 articles of primary data. These articles are discrepant, making the classification of a young child's death following a reported short fall problematic. This case report contradicts the prevalent belief of many physicians dealing with suspected child abuse that low-height falls by young children are without exception benign occurrences and cannot cause fatal intracranial injuries and severe retinal hemorrhages. The irreparable harm to a caregiver facing an erroneous allegation of child abuse requires physicians to thoroughly investigate and correctly classify pediatric accidental head injuries.     

Choosing relatives for DNA identification of missing persons

DNA-based analysis is integral to missing person identification cases. When direct references are not available, indirect relative references can be used to identify missing persons by kinship analysis. Generally, more reference relatives render greater accuracy of identification. However, it is costly to type multiple references. Thus, at times, decisions may need to be made on which relatives to type. In this study, pedigrees for 37 common reference scenarios with 13 CODIS STRs were simulated to rank the information content of different combinations of relatives. The results confirm that first-order relatives (parents and fullsibs) are the most preferred relatives to identify missing persons; fullsibs are also informative. Less genetic dependence between references provides a higher on average likelihood ratio. Distant relatives may not be helpful solely by autosomal markers. But lineage-based Y chromosome and mitochondrial DNA markers can increase the likelihood ratio or serve as filters to exclude putative relationships.     

Y-haplotype screening of local patrilineages followed by autosomal STR typing can detect likely perpetrators in some populations

The male-specific, human Y-chromosomal short tandem repeats (Y-STRs) are very useful in forensic analysis and human evolution studies. The authors report two sexual crime cases in which the perpetrators were successfully traced using Y-haplotype screening of local patrilineages followed by autosomal STR typing. First, several main local patrilineages from local cases were investigated using Y-STR haplotyping, aimed to find the pedigrees whose haplotypes were identical or similar to those of the crime scene samples. Then, several key suspects were defined from the screened pedigrees, and autosomal STR typing was performed to identify the perpetrator of the crime. The application of Y-haplotype screening of local patrilineages followed by autosomal STR typing in these two cases demonstrates its usefulness for solving sexually related crimes in certain populations.     

Multiplex short tandem repeat amplification of low template DNA samples with the addition of proofreading enzymes

Abstract:  With <100 pg of template DNA, routine short tandem repeat (STR) analysis often fails, resulting in no or partial profiles and increased stochastic effects. To overcome this, some have investigated preamplification methods that include the addition of proofreading enzymes to the PCR cocktail. This project sought to determine whether adding proofreading polymerases directly in the STR amplification mixture would improve the reaction when little template DNA is available. Platinum Taq High Fidelity and GeneAmp High Fidelity were tested in Profiler Plus? STR reactions alone and in combination with AmpliTaq^® Gold. All reactions included the additional step of a post‐PCR purification step. With both pristine low template DNA and casework samples, the addition of these polymerases resulted in comparable or no improvement in the STR amplification signal. Further, stochastic effects and artifacts were observed equally across all enzyme conditions. Based on these studies, the addition of these proofreading enzymes to a multiplex STR amplification is not recommended for low template DNA work.     

微波衍生化和GC/MS/MS技术分析血、尿中的吗啡

目的建立了血、尿等生物检材中海洛因代谢产物吗啡的定性分析方法。方法以丙酸酐为衍生化剂,采用微波衍生化技术结合GC/MS/MS进行分析。结果当CID电压为0.9V时,衍生化物的母离子与子离子碎片信息丰富,碎片为m/e268、324、342。结论此方法科学、准确,灵敏度高,能满足吸食海洛因类、吗啡类毒品人员的生物检材的检验要求。     

Probabilistic expert systems for handling artifacts in complex DNA mixtures

This paper presents a coherent probabilistic framework for taking account of allelic dropout, stutter bands and silent alleles when interpreting STR DNA profiles from a mixture sample using peak size information arising from a PCR analysis. This information can be exploited for evaluating the evidential strength for a hypothesis that DNA from a particular person is present in the mixture. It extends an earlier Bayesian network approach that ignored such artifacts. We illustrate the use of the extended network on a published casework example.     

Allele frequencies for nine STR loci (D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820) in the Italian population

Genotype and allele frequencies for STR loci D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820 were investigated in 289 unrelated Italian Caucasian individuals from the North and South regions. After co-amplification by polymerase chain reaction, automatic DNA profiling of these nine STR loci was performed by ABI PRISM((R)) 310 DNA Genetic Analyzer. For each locus, statistical parameters for forensic and paternity purposes were then calculated; the combined power of discrimination and the combined power of exclusion of all nine loci were 0.9999999999917 and 0.99992 for the Northern population and 0.9999999999921 and 0.99991 for the Southern population.