法医毒理学的结果解释（下）

法医毒理学的主要任务是从生物检材中分析毒（药）物,并且推断毒（药）物浓度对死亡或行为能力的作用程度,结果解释是法医毒理学的最终目的。现代法医毒理学主要包括死后法医毒理学、滥用药物筛查和行为能力影响三个方面,由此探讨在进行结果解释时的诸多影响因素。进行法医毒理学的结果解释时应非常慎重,充分了解案情和调查结果,全面考虑毒（药）物的毒性、生物检材、药代动力学、体内再分布、药物交叉反应等多种因素,才能对案件作出较为准确的结果解释。     

法医毒理学的结果解释（上）

法医毒理学的主要任务是从生物检材中分析毒（药）物,并且推断毒（药）物浓度对死亡或行为能力的作用程度,结果解释是法医毒理学的最终目的。现代法医毒理学主要包括死后法医毒理学、滥用药物筛查和行为能力影响三个方面,由此探讨在进行结果解释时的诸多影响因素。进行法医毒理学的结果解释时应非常慎重,充分了解案情和调查结果,充分考虑毒（药）物的毒性、生物检材、药代动力学、体内再分布、药物交叉反应等多种因素,才能对案件作出较为准确的结果解释。     

法医生物检材管理存在的问题及改进办法的探讨

法医生物检材主要指与案件有关的人体血液(痕)、唾液(斑)、毛发、指甲、体液(精液、阴道斑)及各种组织及其分泌物、排泄物和某些动、植物斑迹,在实际案件工作中主要研究附着这些斑痕的载体,如:衣物、棍棒等。能使这些检材起到最大的证据作用的关键是正确的提取、科学的保存、规范的实验室操作和管理。但是国内的法医生物检材在提取、送检和保存的过程中存在许多问题,严重影响着法医物证学的发展和作为证据其法律的严肃性。笔者认为主要存在以下几方面的问题:(1)从现场提取的物证不及时预处理(如晾干等)、不及时送检,造成一些重要的生物检材…     

定量PCR技术在法医学中应用的研究

目的研究荧光定量PCR技术在法医学中的应用。方法应用Taqman技术对法医各种生物检材进行DNA定量。结果该定量PCR技术对各种法医生物检材进行了准确定量,并判断检材中是否存在抑制物,从而指导了后续STR的检验。结论定量PCR技术是法医DNA检验中一项不可缺少的辅助技术。     

甲卡西酮类新型策划毒品的危害及其检测

甲卡西酮类策划药物是近年出现的新型毒品,在世界范围内已经形成滥用趋势。在介绍甲卡西酮类策划毒品的结构、性质及作用的基础上,对于其滥用现状、危害性和检测方进行了综述,以期对建立复杂生物检材中痕量甲卡西酮类策划毒品的高灵敏检测方法有所助益,对研究甲卡西酮类毒品的毒性作用、体内代谢过程及戒断机制提供参考和依据。     

肋软骨和趾甲在碎尸案中的STR位点检验2例

在碎尸案件中,由于尸块不全及经常高度腐败,使STR位点检验存在一定难度。肋软骨和趾(指)甲并不是目前DNA鉴定的常规检材,为了提高高度腐败尸块DNA鉴定的成功率,对高度腐败尸块的肋软骨和指趾甲的STR位点检验方法进行了研究,总结出了一套成功率高同时比较简便的检验方法,并且在实际检案中得到了可行性结果。1案例例1:在某小河中发现一用塑料布包裹的尸块,经法医检验,为腰以上躯干段尸块,表面皮肤肌肉被凶手用刀割除,高度腐败,推断死亡时间近一个月。例2:在一只旅行包中发现双下肢,经法医检验,股骨自上三分之一处横断,高度腐败,法医推断…     

法医物证学miRNA分析的研究进展

在种属和体液鉴定及降解检材等特殊案件的分析时,转录水平的miRNA所具有的生物属性及表达特点,使其能够发挥基因组DNA所不具备的价值。本文通过概述法医物证学miRNA研究的现状,对法医miRNA分析的研究策略和法医物证学应用前景进行了综述,以期为法医miRNA分析的应用研究提供借鉴。     

二代测序技术在法医遗传学中的应用研究进展(2011～2016)

对生物检材进行DNA分型是解决法医遗传学实践中个体识别和亲权鉴定问题的重要步骤,法医学实践中复杂生物检材和复杂亲缘关系鉴定等一直是现有的检测分析技术的难点和挑战。随着DNA技术的发展,新的检测分析技术不断引入到法医遗传学领域,以期提高检测效能。二代测序技术具有测序通量高、成本低等特点,能够获得样本DNA详细序列和相对含量等信息,有助于生物检材的检测和案件的分析。二代测序技术在法医遗传学领域的应用受到广泛关注,相关的应用研究逐渐增多。本文就目前法医遗传学领域借助二代测序技术对遗传标记分析的研究进展进行总结,希望能为相关研究和应用提供参考。     

腐败生物检材中多种碱性滥用药物的检测

目的建立腐败生物检材中多种碱性滥用药物的提取、净化和仪器分析方法。方法用环己烷作为提取溶剂液-液萃取,同时采用Bond Elut Certify小柱、甲醇淋洗、二氯甲烷:异丙醇:氨水(78:20:2)洗脱固相萃取分离提取,GC/MS、GC/NPD定性定量分析各种生物检材中的滥用药物。结果从所送死者肝组织、胃组织、心血及胃内容、尿样、各检材中均同时检出吗啡、可待因、舒乐安定和异丙嗪成份,其中肝组织含量分别为吗啡0.094μg/g、可待因0.257μg/g、异丙嗪0.110μg/g,尿液含量分别为吗啡0.334μg/ml、可待因4.054μg/ml、异丙嗪0.066μg/ml,心血含量分别为吗啡0.036μg/ml、可待因0.106μg/g、异丙嗪0.088μg/ml。结论此方法准确、可靠、科学,可以用于法医毒物分析领域体内检材多种碱性药物的检测。     

降解生物检材DNA分析研究新进展

在法医检案过程中,如何从降解生物检材中获得正确的DNA分型是法医学界的一个难题。本文对降解生物检材DNA分析研究取得的新进展进行综述,从检案的各个环节出发对近年来提高DNA分型成功率的方法和技术进行了详细介绍,例如新型遗传标记的开发和二代测序技术的应用等。希望为降解检材的分析提供新的思考和方法。     

Nails of newborns in monitoring drug exposure during pregnancy

This project was developed to investigate the usefulness of newborn nails for monitoring in utero drug exposure. Cocaine, benzoylecgonine, morphine, methadone, caffeine, nicotine, and cotinine were determined in nail samples from the first 3 months of life of 25 newborns abandoned immediately after birth (group 1) and of 33 babies born at the local maternity hospital whose families were recruited on a voluntary basis (group 2). All substances were measured by gas chromatography-mass spectrometry (detection limit: 0.025 ng/mg). Moreover, analytical results were compared with mothers' self-reported habits when the information was available. In group 1, 12 nails were found positive for caffeine and 13 for both nicotine and cotinine. Six samples tested cocaine- (range, median: 0.14-0.25, 0.175 ng/mg) and benzoylecgonine-positive (range, median: 0.12-0.20, 0.165 ng/mg). Both nicotine and cocaine were always retrieved together with their main metabolite. Morphine was found in four samples (range, median: 0.10-0.15, 0.125 ng/mg), methadone in five samples (range, median: 0.12-0.26, 0.170 ng/mg) that were found negative for all other compounds. In group 2, two samples tested positive for methadone (0.16, 0.17 ng/mg). The mothers self-report of the use of coffee always corresponded to caffeine positivity in the newborn nails (n=6), whereas six samples tested positive for nicotine and/or cotinine with a non-smoking mother. Sixteen out of the 33 samples of group 2 tested negative for all compounds. In conclusion, for the first time, results showed that, once that sample collection problems are solved, nails of the first period of life can be a very interesting indicator of in utero drug exposure.     

Nail analysis for the assessment of caffeine abuse in Northwest China: A population-based study

Caffeine is the most widely consumed psychoactive agent worldwide and has the potential for abuse, but studies monitoring caffeine abuse in China are scarce. This study aims to estimate the prevalence of caffeine abuse in northwest China and investigate the correlation between caffeine and other drugs in hair and nails using an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Fingernail clippings were collected from 376 participants in northwest China to detect caffeine and 13 other illicit psychoactive drugs and their metabolites. Paired hair and nail samples were collected from 39 participants to investigate the correlation between caffeine and other drugs in hair and nails. The samples were decontaminated, pulverized, and extracted by a high-throughput nail sample preparation method and analyzed by UPLC-MS/MS. The results showed a risk of caffeine abuse in northwest China, with concentrations ranging from 0.43 to 10.6 ng/mg for healthy volunteers, 0.49–246 ng/mg for caffeine abusers, and 0.25–363 ng/mg for drug addicts in community rehabilitation centers. Caffeine was detected together with other illicit psychoactive drugs and their metabolites. Furthermore, positive detection correlations were found between hair and nail samples. This study provides a current perspective on caffeine abuse in northwest China and demonstrates the practical use of UPLC-MS/MS for the simultaneous detection of caffeine and 13 illicit psychoactive drugs and their metabolites in hair and nails. The results highlight the potential of nails as a supplementary matrix when hair samples are unavailable and emphasize the need for handling caffeine carefully given its potential for abuse.     

Determination of ABO(H) blood group substances from finger and toe nails

Thirty-six finger and toe nails were analyzed for ABO(H) blood group substances by the modified absorption elution method. The blood groups from nails were successfully determined in all the samples.     

Examination of pretreatment methods for DNA extraction from nails

In the conventional method of DNA extraction from nails, it takes approximately half a day to dissolve the nails. In this study, we examined whether using the HOrizontal Nail MAshing (HONMA) method, in which pressure is applied to the nail to crush it flat and increase its surface area, would improve DNA extraction efficiency. Fingernails (5 mg) provided by ten volunteers were used as samples. Nail pieces (1–3 pieces), shredded with nail clippers, were thinly stretched by applying 2 t of pressure to each piece using a hydraulic press. DNA was extracted by incubation at 56 °C for 10 min and 1 h during proteolysis. DNA yield from the nails pretreated using the HONMA method increased by 0.20–7.10 times compared with that from unprocessed nails. In particular, 10-min incubation using the HONMA method resulted in an average 2.05-fold increase in DNA yield compared with that under overnight incubation. However, the impact of using the HONMA method varied widely among individuals, and the amount of extracted DNA decreased in some cases, suggesting that the yield may differ depending on the nail quality.     

Validation of PrepFiler™ forensic DNA extraction kit (Applied Biosystems)

The PrepFiler™ is a new kit recently introduced by Applied Biosystems for DNA extraction from a wide range of forensic samples. In the present study we tested the performance of PrepFiler™ kit against other commonly used commercially available kits on a variety of real forensic casework samples: bloodstains on different substrates, washed bloodstains, semen stains, saliva stains, hairs, bones, tissues, nails, prints after chemical treatments, skin swabs.     

二次消化结合磁珠法提取腐败组织DNA

目的 研究二次消化结合磁珠法对3种腐败组织DNA的提取效果.方法 采用二次消化结合磁珠法对用常规磁珠法提取DNA失败的91例高度腐败尸体的软骨、指(趾)甲、关节囊组织提取DNA,QuantifilerTM试剂盒进行DNA定量,用SinofilerTM或MinifilerTM试剂盒进行STR检测分型. 结果 91例高度腐...     

Value of human lip lines and nail striations in identification

The pattern of the lips and the longitudinal striation of the lower concave surface of the nails of fingers and toes can be resource of identification. The types of the lip lines are individual and probably constant for some years. We demonstrated that the pattern of all of 20 human nails are over the space of one year the same and found no interindividual correspondence. The investigation rate for examination amount to 36% for the nails of the fingers and 55% for suchlike toes.     

从指甲中提取DNA进行PCR-STR初步研究

本文成功的提取了指甲中的细胞核DNA,并进行多个PCR-STR位点扩增,具有实际应用价值.     

Quantitative analysis of amplifiable DNA in tissues exposed to various environments using competitive PCR assays

Competitive PCR assays were established for the mitochondrial DNA hypervariable region I and the human amelogenin locus. Using these assays, the copy numbers of DNA participating in PCR (amplifiable DNA) were quantified in tissues exposed to different environments. Human ribs, skin and nails were left in three exposure conditions (in the open air, in soil and in water). The amounts of amplifiable DNA in these tissues were quantified during a time period of up to two months. The amount of amplifiable DNA was well preserved in hard tissues (ribs and nails) regardless of the exposure conditions, whereas the soft tissues immersed in water showed a rapid decrease in amplifiable DNA. Strong PCR inhibition was observed in the DNA extracts obtained from buried bones. This phenomenon was clearly identified from an amplification failure of the internal standards in the competitive PCR. A preliminary examination to identify the PCR inhibitor suggested that the soil itself contributed to the inhibition. In addition, the amounts of amplifiable DNA in case samples were also investigated.     

压力循环技术用于人指甲DNA提取及方法学评价

目的将压力循环技术（PCT）用于指甲DNA提取,并对方法学进行评价。方法收集10份人指甲样本,剪碎约为1mm×1mm大小,采用10%漂白粉水,10%SDS,10%漂白粉水,无菌水清洗样本。10份样本各分成两组,1组用压力循环技术处理,另1组不作处理,提取DNA经复合扩增并进行STR分型检测,用于评价压力循环技术的作用。取5份指甲样本用血浸泡,5份用去离子水浸泡,之后采用上述清洗方法各清洗1-3次,收集各次清洗用的无菌水提取DNA,经STR分型检测,用于评价清洗对去除外源性DNA的效果。结果 10份经压力循环技术处理的样本中有7例比相应未经处理样本DNA提取量更高,但两组进行统计学处理,差异不具有统计学意义（P〉0.05）;两组样本中提取DNA含量在0.026 ng以上的样本均得到完整的STR分型,与相应口腔拭子样本对照准确无误。血污染和非血污染样本清洗二次以上,均可避免外源性DNA的污染。结论使用压力循环技术并配合本文清洗方法,可有效提高人指甲DNA的提取效率,并避免外源性生物DNA的干扰,保证DNA分型结果的准确。