采用Identifiler系统判定消化系统肿瘤组织身源准则探讨

目的 探讨采用Identifiler系统进行消化系统肿瘤组织身源判定时共有等位基因数(IAn)和全相同基因座数(A2)的标准.方法 在对l05对消化系统肿瘤组织-身源正常组织对进行Identifiler系统分型的基础上,依据IAn和A2的有限分布原则,将IAn的16种取值代入已建立的相应判别函数,通过Fisher判别准...     

依据共有STR基因座数判别全同胞关系

目的建立并探讨基于共有STR基因座数的全同胞关系判别方法。方法根据280对全同胞（fullsibling,FS）及2 003对无关个体（unrelated individual,UI）Identifiler系统15个STR基因座的分型结果,采用计数法计算全不同基因座数（A0）、半相同基因座数（A1）和全相同基因座数（A2）,依据ITO法计算每对受试者的全同胞指数（FSI）,应用判别分析得出基于共有基因座数或FSI进行全同胞及无关个体关系判别的Fisher判别函数,并比较其判别效能。结果全同胞对中的A1、A2和无关个体对中的A0、A1均呈正态分布,全同胞对中的A0和无关个体对中的A2均呈偏态分布。A1在两组人群中的分布差异无统计学意义（P〉0.01）。同时采用A0和A2建立的全同胞及无关个体关系的判别函数分别为ZFS=0.99817A0＋4.24442A2-12.77970和ZUI=2.014 56 A0＋1.546 58 A2-7.280 76。采用上述判别函数进行全同胞及无关个体关系判别的平均错判率为0.049 0。上述判别函数的判别效能与基于FSI的判别函数的判别效能差异无统计学意义。结论可以采用Identifiler系统的共有基因座数进行全同胞及无关个体关系的判别,所建立的判别公式的判别效能与经典ITO法相近。     

利用Identifiler分型系统推断同胞关系

目的探讨自主开发的同胞关系鉴定自动分析软件（ASI）对Identifiler分型系统进行同胞关系鉴定的可行性。方法应用本课题组所开发的软件ASI,对151对同胞及31 224对人工模拟无关个体进行Identifiler系统的15个常染色体STR基因座分型进行分析,计算亲权指数（PI）、同胞关系概率（WFS）和等位基因匹配情况,所获数据进行统计分析,自动计算排序。结果当WFS大于99.999%时,同胞个体占39.07%,无关个体占0%,两组具有显著差异,可以推断两个体同胞关系。当WFS介于1%~99.999%范围内,同胞个体和无关个体有部分重叠,同胞个体占60.93%,无关个体占21.3%,两者具有一定差异,可以通过增加检测STR基因座,再结合案情加作Y-STR、m tDNA检测,以推断两个体是否具有同胞关系。当WFS小于1%时,同胞个体占0%,无关个体占78.7%,可以推断两个体不具有同胞关系。个体间等位基因匹配结果表明：在检测Identifiler体系15个STR基因座时,当两个体常染色体STR基因座的全相同数目≥5时,或全不同数目≤1时,提示为同胞关系;当两个体全不同数目≥6时,或全相同数目≤1时,提示为无关个体,以此作为预测有无同胞关系的界值。结论Identifiler系统及同胞关系鉴定自动分析软件ASI可用于推断同胞关系。     

应用常染色体STR基因座共有等位基因数判别全同胞关系

目的建立基于常染色体STR基因座共有等位基因数的全同胞关系判别标准。方法根据280对全同胞及2003对无关个体Identifiler系统15个STR基因座的分型结果,对15个STR基因座的共有等位基因数（S15）和全同胞指数（FSI）进行统计,应用SAS8.2软件包得出Fisher判别函数并与ITO法结果进行比较。结果全同胞对及无关个体对中共有等位基因数目均符合正态分布。采用Identifiler系统15个STR基因座共有等位基因数进行全同胞关系判别时,判别函数分别为：ZFS=3.26970S15-31.51174和ZUI=1.70058S15-8.52411。用上述判别函数进行全同胞/无关个体关系判别时的平均错判率为0.0298。15个STR基因座共有等位基因数法、CODIS13个STR基因座共有等位基因数法与ITO法判别结果差异无统计学意义。结论应用常染色体STR基因座的共有等位基因数判别全同胞关系简便、可信,易于掌握且不受STR基因座等位基因频率的影响。     

IBS评分法鉴定全同胞关系及其临界值查询表的构建CSCD

目的建立包含不同个数STR基因座检测体系在不同错判标准下的IBS临界值和检测效能查询表。方法收集267对全同胞和360对无关个体血样,采用Goldeneye^(TM) 20A体系进行19个常染色体STR基因座的分型,按照《生物学全同胞关系鉴定实施规范》采用IBS评分法判定全同胞关系。通过理论推算,计算包含不同个数STR基因座检测体系在不同错判标准下的IBS临界值和检测效能。结果按照规范的IBS评分标准对全同胞和无关个体的鉴别效能为0.764 0,错判率为0,理论推算和样本观察值相符。包含不同个数STR基因座检测体系的全同胞鉴定IBS评分临界值查询表构建成功。结论该规范的IBS评分法检测效力较高,错判率极低,判定结果相对保守。包含不同个数STR基因座检测体系的全同胞鉴定IBS评分临界值查询表为全同胞鉴定的结果评判提供了重要的参考数据,具有很好的应用价值。     

IBS评分法鉴定全同胞关系及其临界值查询表的构建

目的建立包含不同个数STR基因座检测体系在不同错判标准下的IBS临界值和检测效能查询表。方法收集267对全同胞和360对无关个体血样,采用Goldeneye~(TM) 20A体系进行19个常染色体STR基因座的分型,按照《生物学全同胞关系鉴定实施规范》采用IBS评分法判定全同胞关系。通过理论推算,计算包含不同个数STR基因座检测体系在不同错判标准下的IBS临界值和检测效能。结果按照规范的IBS评分标准对全同胞和无关个体的鉴别效能为0.764 0,错判率为0,理论推算和样本观察值相符。包含不同个数STR基因座检测体系的全同胞鉴定IBS评分临界值查询表构建成功。结论该规范的IBS评分法检测效力较高,错判率极低,判定结果相对保守。包含不同个数STR基因座检测体系的全同胞鉴定IBS评分临界值查询表为全同胞鉴定的结果评判提供了重要的参考数据,具有很好的应用价值。     

共有基因座数和等位基因数用于结直肠癌组织的身源认定

目的 探讨结直肠癌组织中STR基因座变异情况及其身源认定方法. 方法 用Identifiler系统对50对新鲜结直肠癌组织及其身源正常组织(CR-N)组进行STR分型,计算CR-N组中变异STR基因座及全不同基因座数(A0)、半相同基因座数(A1)、全相同基因座数(A2)和共有等位基因数(IAn),比较CR-N组、无关个体对(UI)组和全同胞对(FS)组中上述参数的分布差异,通过判别分析建立判别函数.结果 结直肠癌组织中STR基因座基因型改变发生率为3.33%.CR-N组中A1、A2和IAn呈显著偏态分布并与其在UI或FS组中分布差异显著.依据IAn、A1/A2分别建立了CR-N与UI、CR-N与FS的判别函数,其对结直肠癌组织身源认定错判率均为0.00%. 结论 结直肠癌组织中STR基因座基因型改变发生率较高;本研究所建立的判别函数是进行结直肠癌组织身源认定的一种可行方法.     

同胞鉴定中风险与对策的思考

目的 考察同胞认亲案件鉴定中的风险.方法 在一例同胞关系鉴定中,采用常染色体STR检测系统及X染色体STR检测系统进行基因型分型,并用ITO法计算全同胞指数及统计共有等住基因数和全相同基因座数进行判定.结果 在该案例中,常染色体STR分型结果与X染色体STR分型结果均提示被检验同胞之间并非其声称的全同胞关系,在排除其中非全同胞个体后,对剩余全同胞进行基因型分析从而反推出其生父母基因型,并与被认个体进行基因型比对后得出排除结论,即被认个体与被检验同胞之间不存在生物学全同胞关系.结论 对于同胞认亲的案件,若无父亲和(或)母亲参与,鉴定人应尽可能地通过多种检测系统(常染色体STR、X-STR、Y-STR、mtDNA等)综合分析,从而对被检验同胞所声称的“全同胞”关系进行验证;也可用ITO法计算全同胞指数及统计共有等位基因数和全相同基因座数进行判定,这样可以互相印证鉴定结果,降低误判风险.     

5种免提取试剂盒检验滤纸血痕结果的比较

目的探讨5种免提取试剂盒对滤纸血痕样本检验的效果。方法陈旧滤纸血痕(存放时间12～14个月)及新鲜滤纸血痕(存放时间小于1个月)各920份,分别随机分为5组。应用AGCU 17+1、Goldeneye 20A、Powerplex16HS、Identifiler Plus、Identifiler Direct 5种免提取试剂盒进行检验,对比各组检验结果。结果陈旧滤纸血痕5种试剂盒的检验成功率为98.91%～100%,各组间无差异(P>0.05);新鲜滤纸血痕,Identifiler Plus和Identifiler Direct试剂盒检验成功率高于AGCU17+1、Goldeneye 20A及Powerplex 16HS试剂盒(P<0.01);将样本做陈旧化处理后再用成功率较低的3种试剂盒进行检验,成功率分别升至100%、99.46%、99.46%;Identifiler Plus试剂盒扩增循环27次效果优于28次。结论本文5种试剂盒均可用于滤纸血痕的直接扩增检验,但使用AGCU17+1、Goldeneye 20A及Powerplex 16HS试剂盒需将新鲜血痕做陈旧化处理;Identifiler Plus试剂盒需将循环次数降为27次。     

IBS法鉴定全同胞关系的错判概率分析

目的以随机模拟法进行IBS鉴定全同胞关系的错判概率分析。方法分别在19、29、39个常染色体STR检测系统上,以随机模拟法产生1000万对全同胞和无关个体样本,按照《生物学全同胞关系鉴定实施规范》采用IBS法鉴定全同胞关系,统计假阳性概率和假阴性概率。结果在19个STR检测系统上,按照规范的IBS评分标准的假阳性概率和假阴性概率分别为1.6×10~(-4)和1.4×10~(-4);在29个STR检测系统上的假阳性概率和假阴性概率分别为2.4×10~(-4)和2.3×10-6;在39个STR检测系统上的假阳性概率和假阴性概率分别为2.9×10~(-4)和0。结论规范中IBS法错判概率极低,判定结果保守,具有很好的应用价值。     

Determination of phenotypes of esterases (Set) in fresh saliva and saliva stains by disc electrophoresis and the distribution of Set phenotypes in the Japanese population

A rapid and simple disc electrophoretic technique for the determination of saliva esterase (Set) types is described. The frequency of Set types was F 16.4%, FS 49.8% and S 33.8%. The estimated gene frequency of Set-1F was 0.413 and of Set-1S was 0.587. An accurate determination of Set types was possible in 5 – 7-week-old saliva stains. This system may be useful in medicolegal applications.     

Lessons learned from inter-laboratory studies of carbon isotope analysis of honey

Forensic application of carbon isotope ratio measurements of honey and honey protein to investigate the degree of adulteration with high fructose corn syrup or other C₄ plant sugars is well established. These measurements must use methods that exhibit suitable performance criteria, particularly with regard to measurement uncertainty and traceability – low levels of adulteration can only be detected by methods that result in suitably small measurement uncertainties such that differences of 1‰ or less can be reliably detected. Inter-laboratory exercises are invaluable to assess the state-of-the art of measurement capabilities of laboratories necessary to achieve such performance criteria. National and designated metrology institutes from a number of countries recently participated in an inter-laboratory assessment (CCQM-K140) of stable carbon isotope ratio determination of bulk honey. The same sample material was distributed to a number of forensic isotope analysis laboratories that could not participate directly in the metrological comparison. The results from these studies have demonstrated that the majority of participants provided isotope delta values with acceptable performance metrics; that all participants ensured traceability of their results; and that where measurement uncertainties were reported; these were fit-for-purpose. A number of the forensic laboratories only reported precision rather than full estimates of measurement uncertainty and this was the major cause of the few instances of questionable performance metrics. Reporting of standard deviations in place of measurement uncertainties is common practice outside metrology institutes and the implications for interpretations of small differences in isotopic compositions are discussed. The results have also highlighted a number of considerations that are useful for organisers of similar inter-laboratory studies in the future.     

A promising microbiological test for the diagnosis of drowning

A number of biological and chemical tests have been developed over the years to determine whether a person was drowned. This study focuses on the potential of a microbiological test for detecting common bacterial markers of water faecal pollution such as faecal coliforms (FC) and faecal streptococci (FS) as possible indicators of drowning. A promising previous study was carried out on central and peripheral blood samples of 42 drowned victims (20 cases in saltwater and 22 cases in freshwater) and 30 not-drowned bodies. To improve the accuracy of our previous results and also in order to investigate a possible cause of a false positive due to pulmonary passive diffusion and subsequently endogenous or exogenous bacterial invasion of the blood in the post-mortem interval (PMI), the FC and FS test was applied to bodies submerged in water but died from causes other than drowning. In the present study, blood samples collected from the left ventricle (LV), right ventricle (RV), femoral artery (FA) and, femoral vein (FV) of 10 drowned victims (5 cases in freshwater and 5 cases in seawater) and 3 not-drowned individuals with bodies submerged in water for a while after death have been analysed. Preliminary results are in agreement with other reports dealing with diatoms and marine bacteria that suggest to exclude the hypothesis of a passive penetration of sufficient quantities of drowning medium into circulation after death or during the agonal period. Based on our results there is also no evidence of a relevant dissemination of endogenous micro-flora from the gastrointestinal tract affecting the FS and FC test. There are still several other factors that could influence the applicability of post-mortem FS and FC cultures for the diagnosis of drowning and they need further investigations. The present article provides only a glimpse of the potential of the FS and FC test as bacteriological method for the diagnosis of drowning.     

A simple spectrophotometric method for the determination of carboxyhemoglobin in blood

The spectrophotometric method for the determination of carboxyhemoglobin (HbCO) in blood reported by Fretwurst and Meinecke was modified so as to give the same values of percentage HbCO (HbCO%) as those determined by the oxygen electrode method. Values of HbCO% of nine practical samples determined by both the oxygen electrode method and the present method were nearly identical regardless of the presence of methemoglobin (Met-Hb) in blood. The present method is suitable for forensic practice.     

Operational criteria for the determination of suicide

Suicide is an important public health problem for which we have an inadequate public health database. In the United States, decisions about whether deaths are listed as suicides on death certificates are usually made by a coroner or medical examiner. These certification decisions are frequently marked by a lack of consistency and clarity, and laws and procedures for guiding these decisions vary from state to state and even from county to county. Without explicit criteria to aid in this decision making, coroners or medical examiners may be more susceptible to pressures from families or communities not to certify specific deaths as suicide. In addition, coroners or medical examiners may certify similar deaths differently at different times. The degree to which suicides may be underreported or misclassified is unknown. This makes it impossible to estimate accurately the number of deaths by suicide, to identify risk factors, or to plan and evaluate preventive interventions. To remedy these problems, a working group representing coroners, medical examiners, statisticians, and public health agencies developed operational criteria to assist in the determination of suicide. These criteria are based on a definition of suicide as "death arising from an act inflicted upon oneself with the intent to kill oneself." The purpose of these criteria is to improve the validity and reliability of suicide statistics by: (1) promoting consistent and uniform classifications; (2) making the criteria for decision making in death certification explicit; (3) increasing the amount of information used in decision making; (4) aiding certifiers in exercising their professional judgment; and (5) establishing common standards of practice for the determination of suicide.     

Rapid analysis of 3,4-methylenedioxymethamphetamine: a comparison of nonaqueous capillary electrophoresis/fluorescence detection with GC/MS

Because of the increasing use of 3,4-methylenedioxymethamphetamine (3,4-MDMA), a rapid and sensitive analytical technique is required for its detection and determination. Using nonaqueous capillary electrophoresis/fluorescence spectroscopy (NACE/FS) detection, it is possible to determine this drug at the level 0.5 ppm without any pre-treatment in less than 5 min. After liquid-liquid extraction, the sample can be condensed and a detection limit of 3,4-MDMA in urine of 50 ppb (S/N = 3) can be achieved. The precision of the method was evaluated by measuring the repeatability and intermediate precision of migration time and the corrected peak height by comparison with a 3,4-MDMA-D5 internal standard. With the conventional GC/MS method, it is necessary to derivatize the 3,4-MDMA before injection and the GC migration time also is in excess of 20 min. Therefore, NACE/FS represents a good complementary method to GC/MS for use in forensic analysis.     

Genetic analysis of the skeletal remains attributed to Francesco Petrarca

We report on the mitochondrial DNA (mtDNA) analysis of the supposed remains of Francesco Petrarca exhumed in November 2003, from the S. Maria Assunta church, in Arquà Padua (Italy) where he died in 1374. The optimal preservation of the remains allowed the retrieval of sufficient mtDNA for genetic analysis. DNA was extracted from a rib and a tooth and mtDNA sequences were determined in multiple clones using the strictest criteria currently available for validation of ancient DNA sequences, including independent replication. MtDNA sequences from the tooth and rib were not identical, suggesting that they belonged to different individuals. Indeed, molecular gender determination showed that the postcranial remains belonged to a male while the skull belonged to a female. Historical records indicated that the remains were violated in 1630, possibly by thieves. These results are consistent with morphological investigations and confirm the importance of integrating molecular and morphological approaches in investigating historical remains.