Evaluating the discriminating power of amino acid ratios on distinguishing dark colored hair samples

Human hairs are one of the most commonly encountered items of trace evidence. Currently, conventional methods for hair analysis include microscopic comparison and DNA analysis (nuclear and mitochondrial). Each approach has its own drawbacks. Hair proteins are stable and offer an alternative to DNA testing, as demonstrated with proteomics for distinguishing humans. However, proteomics is complicated and requires identifying peptides to remain intact following harsh sample preparation methods. Alternatively, the actual amino acid content of a hair sample may also offer important identifying information and actually requires proteins and peptides to be broken down completely rather than remaining intact. This study evaluated the discriminating power of using hair amino acid ratios to differentiate hair samples from 10 unrelated individuals with dark colored hair. Hair proteins were digested, derivatized, and analyzed using gas chromatography–mass spectrometry. Amino acid ratios were calculated for each individual and comparisons using ANOVA and post-hoc pairwise t-test with Bonferroni correction were made with amino acid ratios for individuals. Overall, out of the 45 possible pairwise comparisons between all hair samples, 38 (84%) were differentiable. Out of the 36 possible pairwise comparisons between brown haired individuals, 32 (89%) were considered differentiable using univariate statistics. Multivariate statistics were also attempted but, overall, univariate models were sufficient for exclusionary purposes. These results indicate that amino acid ratio analysis can potentially be used as an exclusionary method using hair if DNA analysis cannot be performed, or to corroborate conclusions made following microscopic analysis.     

母血浆中胎儿游离核酸与无创性产前亲子鉴定

近年来,涉及胎儿亲权鉴定的案例逐渐增多。传统胎儿产前亲权鉴定常需有创性取样,故存在一定的风险。母血浆中胎儿游离核酸的发现,给无创性产前亲权鉴定带来了新的契机。本文主要就母血浆中胎儿游离核酸及其在无创性产前亲权鉴定中的应用价值和前景进行简要介绍。     

浓缩、精制及干燥对复方丹参提取液中水溶性成分的影响

目的：筛选出最佳的以丹参为君药的复方中药水提取液的浓缩、精制及干燥工艺及其条件，以使丹参水溶性酚酸尽可能少地被破坏，且其工艺简单、成本低，适宜于大生产。方法：以丹参中丹酚酸为筛选指标，对其精制、浓缩及干燥过程中的工艺条件进行筛选。结果：以90℃减压沈缩，2500r/min、30min离心精制，进口温度为140℃喷雾干燥为最佳的浓缩、精制及干燥条件。结论：该工艺合理、可行，水溶性酚酸得以最大限度地被保留。     

Chemical enhancement of footwear impressions in blood deposited on fabric — Evaluating the use of alginate casting materials followed by chemical enhancement

Most footwear marks made in blood on a surface such as fabric tend to be enhanced in situ rather than physically recovered using a lifting technique prior to enhancement. This work reports on the use of an alginate material to recover the impressed footwear marks made in blood and deposited on a range of fabric types and colours. The lifted marks were then enhanced using acid black 1 and leuco crystal violet with excellent results.This presents a new method for the lifting and recovery of blood impressions in situ from crime scene followed by subsequent mark enhancement of the lifted impression.     

A TLC visualisation reagent for dimethylamphetamine and other abused tertiary amines

Application of citric acid/acetic anhydride reagent (CAR), a colour reagent selective for tertiary amines in solution, improves detection of abused tertiary amino drugs on the TLC plate. The plate is pretreated by a brief immersion in phosphoric acid/acetone solution to suppress colouration. After suppressing, the plate is sprayed with CAR and heated at 100 degrees C, causing tertiary amines to turn red purple within 3 minutes. The sensitivity of this new CAR method is 2.5 to 15-times greater than that of conventional detection with Dragendorff reagent for some of the tertiary amines dimethylamphetamine, methylephedrine, levomepromazine, chlorpromazine, caffeine, theophylline, theobromine and nicotine. This present method provides rapid TLC detection of abused tertiary amino drugs such as phenethylamine, phenothiazine, xanthine derivative, nicotine and narcotics.     

Fatal Overdose of Gamma‐hydroxybutyrate Acid After Ingestion of 1,4‐Butanediol

We report a case of fatal intoxication from 1,4‐butanediol (1,4‐BD), which was ingested by a young and “naïve” gamma‐hydroxybutyrate (GHB) consumer during a party with the co‐ingestion of alcohol, cannabis, and methylene‐dioxy‐methamphetamine. The following drug concentrations were found using gas chromatography coupled with mass spectrometry on autopsy samples and on a cup and a glass found at the scene: 20,350 mg/L (bottle) for 1,4‐BD; 1020 mg/L (femoral blood), 3380 mg/L (cardiac blood), 47,280 mg/L (gastric content), and 570 mg/L (vitreous humor) for GHB. The concentration of GHB is difficult to interpret in forensic cases due to the possibility of an endogenous production of GHB. The variable tolerance of the user may also modify the peri‐ and postmortem GHB concentrations. This case underscores the need to have many different sources of toxicology samples analyzed to avoid the hypothesis of endogenous production of GHB.     

Diagnostic Value of PSA and AP Tests for the Detection of Spermatozoa in Postmortem Swabs from the Genital and Anal Region in Males

The aim of this study was to clarify whether positive results for prostate‐specific antigen (PSA) and acid phosphatase (AP) occur in postmortem swabs from the genito‐anal region in males (n = 80; 4 regions) and females (n = 20; 3 regions) and to calculate the positive predictive value (PPV) concerning the presence of spermatozoa. In male subjects, the highest incidence of positive test results was found in urethral swabs (PSA 76%, AP 71%) and the lowest frequencies appeared in perianal and rectal swabs (15–20%). Microscopic evaluation for spermatozoa was positive between 39% in urethral swabs and 1% in rectal swabs. PPV regarding positive identification of spermatozoa was 33.3% for PSA and 31.5% for AP. The combination of both tests yielded a PPV of 38.2%. In female cases, no spermatozoa were identified, and one case was PSA‐ and AP‐positive in perianal swabs. Our findings indicate that PSA and AP tests are of limited value for the postmortem detection of spermatozoa in male subjects.     

石胆酸诱发豚鼠胆囊炎动物模型的病理学研究

以酶病理组织化学方法结合胆汁生化分析，研究了石胆酸（ＬＣＡ）诱发豚鼠胆囊炎和胆结石的形成过程中，肝胆系统内源性β葡萄糖苷酸酶（βＧＣＤ）、酸性粘多糖及多种胆汁成分的变化。结果表明，ＬＣＡ能造成肝损伤，引起豚鼠增生性胆囊炎病变；肝和胆囊中内源性βＧＣＤ活性明显升高；胆汁βＧＣＤ含量显著升高，且与ＵＣＢ／ＴＢ比值显著正相关。     

新藤黄酸诱导脑胶质瘤细胞U87自噬的研究

目的 观察不同浓度新藤黄酸（gambogenic acid,GNA）对脑胶质瘤细胞U87增殖及自噬的影响。方法 倒置显微镜下观察细胞形态变化,采用噻唑蓝法检测细胞的存活率,单丹磺酰尸胺（monodansylcadaverine,MDC）染色法检测自噬泡的形成,吖啶橙（acridine orange,AO）染色流式细胞仪观察酸性囊泡细胞器的数量变化,Westernblot法检测自噬相关蛋白微管相关蛋白1轻链3（microtubule associated protein 1 light chain 3,LC3）- Ⅱ/LC3- Ⅰ以及Beclin- 1的表达变化。结果 GNA在1~32 μmol/L浓度范围抑制U87细胞的增殖;MDC染色表明GNA促进U87细胞内自噬泡的形成;AO染色表明GNA增加U87细胞内酸性囊泡细胞器的数量;Western blot结果显示,GNA作用U87细胞后,LC3- Ⅱ/LC3- Ⅰ比值增大,Beclin- 1的表达增加,提示细胞内自噬活性增强。结论 GNA在一定剂量和时间范围内抑制脑胶质瘤细胞U87细胞的增殖可能与诱导U87细胞自噬的发生有关。