毛发分析前沿——头发微样技术研究进展

毛发分析在司法鉴定实践中具有重要的证据作用和应用价值。然而传统的头发分段分析对于摄毒时间和摄毒模式的评估仍存在较大的误差,由此以单根头发或单根头发毫米或亚毫米分段的头发微样技术得以提出、开发和研究,并以其独特的方法策略和信息特点较为精准地表征单根头发中外源性物质的分布情况和浓度高峰位置。通过主题搜索对国际上涉及头发微样技术的相关研究报道进行综述,包括头发微分段分析的方法学研究、摄毒时间评估研究、头发中毒物分布研究、毒物进入头发机制研究、毛根中毒物动力学研究等,并对头发微样技术的局限性和应用前景作出评述。     

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。     

甲基苯丙胺和氯胺酮在家兔体内毒代动力学及相互影响

目的比较家兔单独静脉注射甲基苯丙胺、氯胺酮及二种药物联合静注时的毒物代谢动力学过程,评价二种药物毒代动力学的相互作用。方法单用甲基苯丙胺组以3mg/kg剂量家兔静脉注射甲基苯丙胺,单用氯胺酮组以30mg/kg剂量家兔静脉注射氯胺酮,合用组以相同剂量同时注射两种药物。分别于给药后不同时间点收集血浆标本,测定各时间点药物浓度,WinNonLin软件拟合毒代动力学房室模型并计算参数。结果甲基苯丙胺在家兔体内的毒代动力学过程呈一级动力学特征,符合单室模型,合用氯胺酮后不改变其模型类型。氯胺酮在家兔体内的毒代动力学过程呈一级动力学特征,符合单室模型,合用甲基苯丙胺后符合二室模型。结论甲基苯丙胺和氯胺酮可以相互延缓其在体内的消除过程,增加彼此在体内的吸收,从而延长作用时间。     

毒鼠磷中毒检验的实验研究 Ⅱ、毒鼠磷的定性定量分析

毒鼠磷中毒的检材采取及预处理问题,己在“毒鼠磷中毒检验的实验研究—Ⅰ”文中作了讨论。本文研究采用薄层层析(TLC)、薄层扫描(TLCS)、高效液相色谱(HPLC)等方法定性定量分析生物体内的毒鼠磷,取得较为满意的结果。这些方法简便、灵敏、重现性较好。且薄层色谱法和高效液相色谱法间具有良好的相关性,r=0.996。方法适合于毒鼠磷中毒案的检验。     

中毒家兔血清中地芬尼多检测研究

采用气相色谱法分析了中毒家兔血清中地芬尼多浓度的经时变化，研究了其毒代动力学过程，测定了尿、胆汁中地芬尼多的含量。     

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。     

藿香正气水中中药成分对大鼠体内乙醇代谢的影响

目的研究服用藿香正气水后,大鼠体内乙醇含量及药代动力学参数的变化。方法将大鼠随机分为3组,分别按3.0 m L/kg剂量灌胃白酒、低浓度中药酒和高浓度中药酒,于给药前(0 min)和给药后5 min、10 min、15 min、30 min、1 h、2 h、3 h、4 h、5 h、6 h、8 h断尾采血,用顶空-气相色谱法测定大鼠血液中的乙醇含量,用DAS 2.0软件计算乙醇的药代动力学参数,SPSS 17.0软件对药代动力学参数进行分析。结果高浓度中药酒组与白酒组最大血药浓度相比,差异有统计学意义(P0.05);其他药代动力学参数在三组间差异均无统计学意义(P0.05)。结论藿香正气水中中药成分对大鼠体内乙醇代谢和消除无明显影响。本研究对涉及饮用藿香正气水导致的交通案(事)件的定性判定和处理以及药物间的相互作用研究具有参考意义。     

氯氰菊酯及其代谢物在犬胆汁中的代谢动力学研究

目的研究氯氰菊酯及其代谢物在犬胆汁中的毒物动力学,为氯氰菊酯中毒的法医学鉴定提供实验依据。方法 6只雄性犬胆囊造瘘术后,经口灌胃1/4LD50剂量的氯氰菊酯,于不同时间点收集胆汁,二氯甲烷液液萃取法提取,高效液相色谱-串联质谱仪分析,MRM记录方式,保留时间和定性离子对定性,内标法和标准曲线法定量检测其中氯氰菊酯(CYM)、3-苯氧基苯甲酸(3-PBA)、二氯菊酸(DCVA)含量,Win Nonlin拟合C-T曲线,计算毒代动力学参数。结果经口灌胃1/4LD50氯氰菊酯后,氯氰菊酯及其代谢物在犬胆汁中的毒物动力学过程均符合一级动力学模型,达峰时间分别为1.52±0.30、1.29±0.04、0.93±0.41 h,达峰浓度分别为0.38±0.03、7.9±1.32、30.9±16.24μg/m L,半衰期分别为3.93±0.71、1.36±0.11、4.49±2.81 h。结论经口灌胃后氯氰菊酯及其代谢物3-苯氧基苯甲酸、二氯菊酸的毒物动力学符合一级吸收代谢动力学模型,模型和参数可以为氯氰菊酯中毒的法医学鉴定提供实验依据。     

法医毒物化学专业

法化学研究室成立于1956年,现有化学、药学、卫生学、检验学专业人员8名,其中高级职称5名、中级职称2名、初级职你1名。 法化学专业主要从事法医毒物分析及毒理学方面的鉴定、研究、教学工作。运用化学、物理学、生物学的原理和方法,对体内外未知毒(药)物进行定性和定量分析;并运用毒理学理论和方法,通过对毒(药)物的毒性、中毒机理、代谢动力学及卫生等方面问题的分析,综合作出毒(药)物中毒的性质、方式、程度及危害的评定。另外法化学专业也从事一些相关的化学鉴定工作。 主要仪器设备有气相色谱仪(GC)、高效液相色谱仪(HPLC)、气/质联用仪(GC/MS、GC/MS/MS),顶空分析仪(HS)、薄层扫描仪(TLC)、紫外分光光度仪(UV)及固相微萃取装置(SPME)等。     

Hematology and pathology devices; reclassification; restricted devices; OTC test sample collection systems for drugs of abuse testing--FDA. Proposed rule

The Food and Drug Administration (FDA) is proposing to reclassify over-the-counter (OTC) test sample collection systems for drugs of abuse testing from class III (premarket approval) into class I (general controls), and to exempt them from the premarket notification (510(k)) and current good manufacturing practice (CGMP) requirements. FDA is also proposing to designate OTC test sample collection systems for drugs of abuse testing as restricted devices under the Federal Food, Drug, and Cosmetic Act (the act), and to establish restrictions intended to assure consumers that: The underlying laboratory test(s) are accurate and reliable; the laboratory performing the test(s) has adequate expertise and competency; and the product has adequate labeling and methods of communicating test results to consumers. Finally, FDA is proposing a conforming amendment to the existing classification regulation for specimen transport and storage containers, to clarify that it does not apply to specimen transport and storage containers that are part of an OTC test sample collection system for the purpose of testing for the presence of drugs of abuse or their metabolites in a laboratory.     

Hematology and pathology devices; reclassification; restricted devices; OTC test sample collection systems for drugs of abuse testing. Food and Drug Administration, HHS. Final rule

The Food and Drug Administration (FDA) is reclassifying over-the-counter (OTC) test sample collection systems for drugs of abuse testing from class III (premarket approval) into class I (general controls) and exempting them from premarket notification (510(k)) and current good manufacturing practice (CGMP) requirements. FDA is also designating OTC test sample collection systems for drugs of abuse testing as restricted devices under the Federal Food, Drug, and Cosmetic Act (the act) and establishing restrictions intended to assure consumers that: The underlying laboratory test(s) are accurate and reliable; the laboratory performing the test(s) has adequate expertise and competency; and the product has adequate labeling and methods of communicating test results to consumers. Finally, FDA is adding a conforming amendment to the existing classification regulation for specimen transport and storage containers to clarify that it does not apply to specimen transport and storage containers that are part of an OTC test sample collection system for the purpose of testing for the presence of drugs of abuse or their metabolites in a laboratory.     

司法鉴定在刑事侦查中的运用

司法鉴定在侦查中对案件事实证明发挥积极作用的同时,也引发错误认定事实的风险。近年来,侦查中运用司法鉴定的比例有所提升,但刑事错案的背后揭示鉴定样本的收集过程在规范化、程序化方面做得还不够。鉴定意见随着案卷进入后续程序,并对案件事实的认定发挥证明作用。侦查中的司法鉴定存在运用尚不充分、样本的收集保管不够规范、司法人员迷信鉴定意见等问题。其进路在于进一步提高侦查中的鉴定技术含量,规范鉴定样本的收集程序,转变对鉴定意见迷信的观念。     

DNA Purification Cell Lysis and Wash Step Modifications for Low-Template DNA Sample Processing,

As DNA technology becomes increasingly sensitive, forensic laboratories are receiving more low-template DNA samples. These samples, already low in DNA content, become even more challenging to process as the available DNA becomes further reduced during the extraction step. In this study, two extraction modifications were tested to determine if the cause of DNA loss could be identified and mitigated. A double lysis technique was used to test for DNA loss in the sample collection substrate, and lysate eluates were re-extracted to determine DNA loss from inefficient binding to the silica column. Both modifications showed DNA was lost at these steps. However, resulting STR profiles from these samples had fewer peaks and lower peak heights when compared to samples processed with no extraction modifications. Overall, the potential benefits of adding these extraction modifications for low-template DNA sample processing are not enough to justify the risk associated with additional manipulation.     

家兔玻璃体液微量取样与一次取样的比较

目的比较微量取样与一次取样的优劣。方法36只家兔分为4组(每组9只),于死后12h取样:I组于一次取出所有VH;II组微量取样50μl,连续取15次;III组左眼一次取样。右眼微量重复取样。IV组双眼第1次微量取样,剩余一次取出。检测Ca2 、Cl-、K 、Na 和P等含量,数据统计分析。结果III组左右眼、(IV)组先后两次取样配对t检验无差异(P>0.05),各组微量取样样本的变异系数、双眼差较小。结论微量取样的操作影响较小、稳定性和重复性好,更适合法医学研究和应用。     

Hair combing to collect organic gunshot residues (OGSR)

A protocol is presented for the collection and analysis of gunshot residues (GSR) from hair. A fine-toothed comb is used for collection of the residues. A small zip-closure bag serves as a container for both sample storage and extraction of the characteristic organic powder additives. The success of this residue recovery approach was tested on simulated shooters and victims using mannequin-supported human wig hair as well as on human shooters. Residues were collected from four weapons: a revolver and semi-automatic pistol, rifle and shotgun. One characteristic additive, nitroglycerin, was detected by capillary electrophoresis (CE) in the majority of the collection experiments.     

Society of Hair Testing guidelines for drug testing in hair

The Society of Hair Testing (SoHT) Guidelines for Drug Testing in Hair provide laboratories with recommended best practice guidelines whether they are currently offering drug testing in hair, or plan to offer a hair testing service in the future. The guidelines include reference to recommended sample collection and storage procedures, through sample preparation, pre-treatment and analysis and the use of cut-offs.     

Paint and tape: collection and storage of microtraces of paint in adhesive tape

The collection and preservation of microtrace evidence with the aid of an adhesive tape is a method of choice in forensic science. This technique is rapid and easy and allows the concentration of microtraces on a carrier, which facilitates further investigations in the laboratory. Adhesive tapes are currently used to secure microtraces of fibers and glass, but hardly for traces of automotive paint and other lacquers for fear of interference with the analysis of binders. A collection of automotive paint consisting of original and repair lacquers collected by tape has been evaluated. After various times of storage within the tape, these samples were compared with untreated references by microscope FT-IR and microspectrophotometry (MSP). Another set of paints was collected in 1984, stored within the tape until 1995, and examined the same way. About 170 layers of lacquer with various types of binder were examined. With the exception of one clear lacquer no difference between treated samples and references was detected. This small difference observed could be correlated to the exposure to xylene (extractant) and was not caused by the storage within the adhesive tape.     

Assessing a novel room temperature DNA storage medium for forensic biological samples

The ability to properly collect, analyze and preserve biological stains is important to preserving the integrity of forensic evidence. Stabilization of intact biological evidence in cells and the DNA extracts from them is particularly important since testing is generally not performed immediately following collection. Furthermore, retesting of stored DNA samples may be needed in casework for replicate testing, confirmation of results, and to accommodate future testing with new technologies.A novel room temperature DNA storage medium, SampleMatrix™ (SM; Biomatrica, Inc., San Diego, CA), was evaluated for stabilizing and protecting samples. Human genomic DNA samples at varying amounts (0.0625-200 ng) were stored dry in SM for 1 day to 1 year under varying conditions that included a typical ambient laboratory environment and also through successive freeze-thaw cycles (3 cycles). In addition, spiking of 1-4× SM into samples prior to analysis was performed to determine any inhibitory effects of SM. Quantification of recovered DNA following storage was determined by quantitative PCR or by agarose gel electrophoresis, and evaluation of quantitative peak height results from multiplex short tandem repeat (STR) analyses were performed to assess the efficacy of SM for preserving DNA.Results indicate no substantial differences between the quality of samples stored frozen in liquid and those samples maintained dry at ambient temperatures protected in SM. For long-term storage and the storage of low concentration samples, SM provided a significant advantage over freezer storage through higher DNA recovery. No detectable inhibition of amplification was observed at the recommended SM concentration and complete profiles were obtained from genomic DNA samples even in the presence of higher than recommended concentrations of the SM storage medium. The ability to stabilize and protect DNA from degradation at ambient temperatures for extended time periods could have tremendous impact in simplifying and improving sample storage conditions and requirements. The current work focuses on forensics analysis; however this technology is applicable to all endeavors requiring storage of DNA.     

Advantage of ForensiX Swabs in Retrieving and Preserving Biological Fluids

This study compares two novel swabs (forensiX) with a standard cotton swab (EUROTUBE) for the collection of saliva stains on glass slide for STR analysis. ForensiX collection tubes are a standard cotton swab in an “active drying” tube, where swab sample is soon dried by its innovative tube surface of the wall. The other is forensiX Nylon Flocked Swab. The study is two phases: The first “phase” assesses swab types regarding to retrieve ability of saliva. The second “phase” compares the drying ability of each swab to assess how crime samples would fare when left in storage. The main result showed that “active drying” is effective to store swabbed sample. The forensiX swabs generally are effective for higher (twofold to fourfold) DNA yield compared to delta lab swab (around 750 pg and 250 pg from 0.5 μL of saliva), respectively. These findings demonstrate the importance of drying performance in the preservation of DNA and swab selection.