RNA指标在死后人体皮肤组织中稳定性研究

目的探讨多种RNA指标的表达水平在死后人体皮肤组织中的稳定性。方法收集死亡时间(PMI)明确的人体皮肤组织样本10例,提取总RNA,运用实时荧光定量PCR(qRT-PCR)技术检测ACTB、GAPDH、18S、miR-203、5S、1et-7a、RPS29、U6共计8个RNA指标的表达水平。geNorm软件评估各RNA指标表达水平的稳定性,挑选出稳定的内参指标并分析其表达水平与相关因素(年龄、性别、死因)的关系。结果人体皮肤组织中5S、U6和miR-203表达水平最为稳定,其平均表达量与年龄、性别、及死因无关(P0.05)。结论 5S、U6和miR-203可以作为qRT-PCR方法研究PMI的理想内参指标。     

大鼠尸体细菌演替规律及其在死亡时间推断中的应用(英文)

目的探讨大鼠尸体细菌演替规律并评估其在死亡时间(PMI)推断中的应用价值。方法选取成年雌性SD大鼠,处死后置于纸箱内自然腐败,采集大鼠眼周皮肤、口腔和阴道三个部位的细菌样本,使用纯培养生化方法鉴定菌种,记录菌群构成变化规律。结果大鼠三个部位细菌演替规律显示,葡萄球菌属和奈瑟菌属为死后初期的优势菌属,尤其是金黄色葡萄球菌与乳糖奈瑟菌在死后6 h内相对含量较高。干酪乳杆菌规律地出现在死后第3或第4天,且在死后晚期维持较恒定水平。结论大鼠死后三个部位的正常细菌及腐败细菌呈现一定的演替规律,可用于PMI推断。     

Determination of Both Fetus’ and Mother's Blood Type from an Autopsy Case Immersed in Formalin for Over 50 Years

A female fetus which had been immersed in formalin for more than 50 years was found in Japan. Because no liquid blood could be obtained, we tried to use immunohistochemistry (IHC) methods to tissue samples obtained at autopsy to identify both the fetal and mother's blood type. We detected B antigens on endothelial cells in paraffin sections of the fetal organs. Furthermore, we observed both anti‐A‐ and anti‐B‐positive red blood cells in the intervillous space, which is indicative of the mother's blood type. To our knowledge, this is the first case report on determining the blood type of both the fetus and the mother from tissue immersed in formalin for such a long time. The results suggest that IHC is valuable for the determination of ABO blood type in circumstances of long postmortem duration and unfavorable storage conditions.     

Evaluation of Postmortem Cerebrospinal Fluid S100B Protein and Serotonin Levels: Comparison of Suicidal Versus Nonsuicidal Deaths in Konya,Turkey

Although suicide is a preventable public health problem, objective assays for suicide risk are limited. In this study, it was aimed to determine levels of S100B protein and serotonin as a marker for risk of suicide. S100B protein and serotonin levels were investigated with ELISA method in the cerebrospinal fluid (CSF) in medicolegal autopsy cases, including those of suicide cases (n = 32) and nonsuicide cases (n = 56). The CSF S100B levels were higher (9.3 ± 2.9 ng/mL vs. 5.4 ± 2.0 ng/mL), and serotonin levels were lower (10.4 ± 4.9 ng/mL vs. 19.0 ± 5.7 ng/mL) in suicide group than nonsuicide group (p < 0.05). There was no correlation between S100B protein and serotonin levels with gender, age groups, postmortem interval, and cause of death. It is concluded that both S100B protein and serotonin in CSF may be useful for determination of suicide risk.     

Developmental Times of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) at Constant Temperatures and Applications in Forensic Entomology

The characteristic life stages of infesting blowflies (Calliphoridae) such as Chrysomya megacephala (Fabricius) are powerful evidence for estimating the death time of a corpse, but an established reference of developmental times for local blowfly species is required. We determined the developmental rates of C. megacephala from southwest China at seven constant temperatures (16–34°C). Isomegalen and isomorphen diagrams were constructed based on the larval length and time for each developmental event (first ecdysis, second ecdysis, wandering, pupariation, and eclosion), at each temperature. A thermal summation model was constructed by estimating the developmental threshold temperature D₀ and the thermal summation constant K. The thermal summation model indicated that, for complete development from egg hatching to eclosion, D₀ = 9.07 ± 0.54°C and K = 3991.07 ± 187.26 h °C. This reference can increase the accuracy of estimations of postmortem intervals in China by predicting the growth of C. megacephala.     

Determination of Human Chorionic Gonadotropin in Postmortem Samples in Ectopic Pregnancies

Increased human chorionic gonadotropin levels (HCG) can be detected in femoral blood, bile, and vitreous humor collected during autopsy of pregnant women using a standard kit designed for living patients. In the study herein, the concentrations of HCG were measured in postmortem serum, vitreous, bile, cerebrospinal, and pericardial fluids in 4 cases of fatal ectopic pregnancy and 40 controls using a quantitative electrochemiluminescence immunoassay designed for living patients. No false‐negative cases were identified in any of the analyzed samples in any of the ectopic pregnancy cases. No correlations were found between total HCG levels in postmortem serum and the other tested specimens. The results of this study would suggest that higher HCG in bile, vitreous, pericardial, and cerebrospinal fluids may confirm the existence of ectopic pregnancy and therefore identify other situations in which this hormone is increased, although gestational age cannot be reliably estimated using these values.     

Predicting the postmortem interval using human intestinal microbiome data and random forest algorithm

Gradual changes in microbial communities in a human body after death can be used to determine postmortem interval (PMI). In this study, gut microflora samples were collected from the vermiform appendix and the transverse colon of human cadavers with PMIs between 5 and 192 h. The results revealed that the appendix might be an excellent intestinal sampling site and the appendix flora had an inferred succession rule during human body decomposition. Firmicutes, Bacteroidetes, and their respective subclasses showed a predictable succession rule in relative abundance over time. A Random Forest regression model was developed to correlate human gut microbiota with PMI. We believe that our findings have increased the knowledge of the composition and abundance of the gut microbiota in human corpses, and suggest that the use of the human appendix microbial succession may be a potential method for forensic estimation of the time of death.     

Identifying background microbiomes in an evidence recovery laboratory: A preliminary study

16S rRNA profiling of bacterial communities may have forensic utility in the identification or association of individuals involved with criminal activities. Microbial profiling of evidence may, in the future, be performed within environments currently utilised for human DNA recovery, such as a forensic biology laboratory. It would be important to establish the background microbiome of such an environment to determine the potential presence of human or environmental microbial signatures to assist forensic scientists in the appropriate interpretation of target microbial communities. This study sampled various surfaces of an Evidence Recovery Laboratory (ERL) on three occasions including (a) before a monthly deep-clean, (b) immediately following the deep-clean, and (c) immediately after the laboratory’s use by a single participant for the purposes of routine item examinations. Microbial profiles were also generated for the involved participant and researcher for comparison purposes. Additionally, human nuclear DNA was profiled for each of the samples collected, using standard forensic profiling techniques, to provide a prospective link to the presence or absence of a background microbial signature within the ERL after its use. Taxonomic distributions across ERL samples revealed no consistent signature of any of the items sampled over time, however, major phyla noted within all ERL samples across the three timepoints were consistent with those found in human skin microbiomes. PCoA plots based on the Unweighted Unifrac metric revealed some clustering between participant microbial reference samples and surfaces of the ERL after use, suggesting that despite a lack of direct contact, and adherence to standard operating procedures (SOPs) suitable for human DNA recovery, microbiomes may be deposited into a forensic setting over time. The reference samples collected from the involved participant and researcher generated full STR profiles. Human DNA was observed to varying degrees in samples taken from the ERL across each of the sampling timepoints. There was no correlation observed between samples that contained or did not contain detectable quantities of human nuclear DNA and microbial profile outputs.     

Fatal intoxication with 1,4-butanediol: Case report and comprehensive review of the literature

A fatal case of 1,4-butanediol (1,4-BD) oral ingestion is reported here, in which a 51-year-old man was found dead in his bed. According to the police report, the deceased was a known drug user. A glass bottle labeled (and later confirmed to be) “Butandiol 1,4” (1,4-BD) was found in the kitchen. Furthermore, the deceased's friend stated that he consumed 1,4-BD on a regular basis. The autopsy and histological examination of postmortem parenchymatous organ specimens did not revealed a clear cause of death. Chemical-toxicological investigations revealed gammahydroxybutyrat (GHB) in body fluids and tissues in the following quantities: femoral blood 390 mg/L, heart blood 420 mg/L, cerebrospinal fluid 420 mg/L, vitreous humor 640 mg/L, urine 1600 mg/L, and head hair 26.7 ng/mg. In addition, 1,4-BD was qualitatively detected in the head hair, urine, stomach contents, and the bottle. No other substances, including alcohol, were detected at pharmacologically relevant concentrations. 1,4-BD is known as precursor substance that is converted in vivo into GHB. In the synoptic assessment of toxicological findings, the police investigations and having excluded other causes of death, a lethal GHB-intoxication following ingestion of 1,4-BD, can be assumed in this case. Fatal intoxications with 1,4-BD have seldom been reported due to a very rapid conversion to GHB and, among other things, non-specific symptoms after ingestion. This case report aims to give an overview to the published of fatal 1,4-BD-intoxications and to discuss the problems associated with detection of 1,4-BD in (postmortem) specimens.     

Development and validation of a LC–MS/MS method for analysis of vortioxetine in postmortem specimens. First data from an authentic case

Vortioxetine is an antidepressant recently licensed in USA and EU for the treatment of major depressive disorder. Neither fatal case due to overdose nor data about postmortem concentrations on blood or other specimens have been reported. The aims of this study were the development and validation of a method for vortioxetine analysis by Liquid Chromatography Tandem Mass Spectrometry (LC–MS/MS) in postmortem samples and its application in an authentic case. The method was validated and applied on blood, vitreous humor, bile, brain, liver, kidney, and gastric content. After protein precipitation, the supernatant was directly injected into LC–MS/MS. Analysis was carried out by Multiple Reaction Monitoring (MRM) mode. The authentic case concerned a 38 years-old woman, affected by depression, who was found hanged at home. The method determined an acceptable sensitivity, selectivity, linearity, precision, and accuracy for all matrices. No interference was shown for all matrices. The matrices do not significantly reduce the peak intensity of vortioxetine. No carryover was shown. Toxicological analysis of the authentic case showed vortioxetine in blood (234 ng/ml), vitreous humor (10.5 ng/ml), brain (490 ng/g), lung (479 ng/g), liver (3751 ng/g), kidney (798 ng/g), bile (2267 ng/ml) and gastric content (253 ng/ml). Our case suggests that even at blood concentrations of vortioxetine equal to 234 ng/ml, the subject was able to stage and carry out the hanging. Vortioxetine concentrations found in the other cadaveric samples (biological fluids, organs, and gastric content) may be helpful to evaluate further similar comparable cases.