甲拌磷在大鼠体内的死后分布研究

目的建立甲拌磷灌胃染毒致死的大鼠动物模型,建立生物检材中甲拌磷的气相色谱和气相色谱质谱联用检测方法 ,观察甲拌磷在3种剂量染毒大鼠体内的死后分布特点。方法大鼠2LD50、4LD50或8LD50甲拌磷灌胃染毒,死后立即解剖,采集心、肝、脾、肺、肾、脑、肌肉、睾丸、心血和胃组织,GC/MS、GC/FPD法定性定量检测各组织和心血中甲拌磷。结果大鼠2LD50、4LD50和8LD50甲拌磷染毒后31±3min、19±4min和11±6min死亡。气相色谱和气相色谱质谱联用法均可检到甲拌磷。染毒死亡大鼠体内甲拌磷的含量由高到低顺序依次为：2LD50组：胃组织〉肝〉脾〉肾〉肺〉脑〉睾丸〉肌肉〉心〉心血。4LD50组：胃组织〉肝〉肺〉脾〉肾〉睾丸〉肌肉〉脑〉心〉心血。8LD50组：胃组织〉肝〉肾〉脾〉肺〉心〉肌肉〉睾丸〉心血〉脑。结论甲拌磷在大鼠体内死后分布不均匀。胃组织中含量最高,其次是肝、脾、肺和肾,脑、肌肉和睾丸含量最低。甲拌磷的灌胃染毒致死动物模型、气相色谱和气相色谱质谱联用方法及死后分布规律可应用于甲拌磷中毒死亡案件的法医学鉴定和法医毒物动力学研究。     

家兔死后体表锐器伤出血现象的研究

目的对家兔死后体表锐器损伤出血现象进行研究,以期能够贴近实际办案需要,找到一个更为实用的鉴别生前锐器伤和死后锐器伤的方法。方法家兔脱毛,制作锐器损伤模型,采用大体观察结合HE染色镜下组织病理学观察。结果死后锐器损伤出血量均较少,随着时间延长出血量减少,出血速度慢。死后30min的锐器损伤在形成过程与生前损伤有所区别,但在死后12h肉眼观察结果与生前损伤难以区别。死后1h以上的锐器损伤与生前损伤不同之处在于创缘不会被血染。结论位于尸体低下位置的死后30min内的锐器创与生前锐器创的区别是出血量相对较少。死后60min-90min的锐器伤出血量少,创缘皮肤不被血染,肌肉的出血较局限,与生前损伤相鉴别较容易。     

不同环境条件下大鼠死后皮肤大体和组织学改变

目的研究观察大鼠在不同环境条件下死后不同时间其皮肤大体、组织学的改变,为推测较长的死后间隔时间建立实验动物依据。方法观察雌性SD大鼠在不同环境条件下的死后变化,并间隔一定死后时间取皮、染色和镜下观察。结果死后发生骨、软组织分离,A组约需35d,B组需13d。皮肤有形细胞成分和附属器完全分解破坏,A组约20d,B组7d。胶原纤维在A组死后40d（B组12d）仍有部分保留完整。结论环境温度差异是造成A、B两组发生死后改变时程不同的主要因素,利用皮肤大体、组织学改变可望较系统和准确的推测晚期死亡时间。     

Postmortem Serum Tryptase Levels with Special Regard to Acute Cardiac Deaths

An elevated serum tryptase concentration is considered a specific marker for systemic mast cell activation, a central feature of anaphylaxis. However, in some cases of acute cardiovascular death, high concentrations of serum tryptase are also observed. We compared the postmortem serum tryptase concentrations in 74 cases assigned to the following four groups: anaphylactic deaths (Group A, n = 20), acute cardiac deaths (Group ACD, n = 30), acute dissecting aneurysm ruptures (Group ADA, n = 10), and controls (Group C, n = 14). Additionally, the cutoff between Group A and the other groups was calculated using receiver‐operating characteristic (ROC) curve analysis. Tryptase concentrations were markedly elevated in Group A (p < 0.001), Group ACD (p = 0.015), and Group ADA (p = 0.005). The optimal cutoff was 43 ng/mL, the sensitivity was 90%, and the specificity was 98%. While elevated concentrations of tryptase were noted in practical autopsy cases, due attention should be paid to the differential diagnosis between anaphylactic and acute cardiovascular deaths.     

大鼠百草枯中毒后体内的分布研究

目的建立生物检材中百草枯的超高效液相色谱-质谱联用检测方法,研究百草枯灌胃染毒致死的大鼠动物模型。方法大鼠以1/2 LD_(50)剂量灌胃染毒,分别于染毒后0.5h、2h、4h、8h、12h、24h、48h、72h处死解剖,采集心、肝、脾、肺、肾、脑、肌肉、膀胱和胃组织,UPLC-MS/MS法定量检测各组织中百草枯。结果试验中大鼠灌胃后,4h以内胃是主要分布器官,胃中含量最多,其他器官中含量相对较低。4h内除胃以外的脏器含量变化不大,4h后胃内百草枯含量有所下降,除胃以外的脏器含量均升高。各组织与脑组织比较具有显著性差异(P0.05)。结论百草枯在大鼠体内死后分布不均匀并且各组织含量随着时间变化有所改变。百草枯UPLC-MS/MS方法、口服染毒致死的动物模型、各组织分布规律可为甲百草枯中毒死亡案件提供检测依据。     

大鼠死后不同组织电导率与死亡时间关系的研究

目的测定不同死亡时间大鼠脑、肺、肝和骨骼肌电导率,研究不同组织器官EC与PMI的关系。方法 SD大鼠处死后,保存于25℃恒温条件下,于死后即刻(0d)、1d、2d、3d、4d、5d、6d和7d提取大鼠脑、肺、肝和骨骼肌,四种组织器官与去离子水按照一定比例制成浸渍液,测定各组织器官浸渍液EC值;分析其EC值与PMI的关系,建立与PMI关系的回归方程;比较大鼠死后四种组织器官EC变化规律,探讨不同组织器官腐败进程。结果死后1d内骨骼肌与脑组织EC无显著变化,2~7d快速增加;而肝、肺EC值在1d内已开始增加,且2~7d内均快速上涨。四种组织器官EC与PMI的关系用三次方程拟合较好,其中肝的相关系数最高,R~2=0.96,且四种组织器官的EC值在不同的PMI区段之间呈现出不同的增长规律。结论大鼠脑、肺、肝和骨骼肌EC与PMI相关性均较好,测定尸体组织器官EC有望成为法医实践中PMI推断的有效方法。     

The Effect of Body Mass on Outdoor Adult Human Decomposition

Forensic taphonomy explores factors impacting human decomposition. This study investigated the effect of body mass on the rate and pattern of adult human decomposition. Nine males and three females aged 49–95 years ranging in mass from 73 to 159 kg who were donated to the Complex for Forensic Anthropology Research between December 2012 and September 2015 were included in this study. Kelvin accumulated degree days (KADD) were used to assess the thermal energy required for subjects to reach several total body score (TBS) thresholds: early decomposition (TBS ≥6.0), TBS ≥12.5, advanced decomposition (TBS ≥19.0), TBS ≥23.0, and skeletonization (TBS ≥27.0). Results indicate no significant correlation between body mass and KADD at any TBS threshold. Body mass accounted for up to 24.0% of variation in decomposition rate depending on stage, and minor differences in decomposition pattern were observed. Body mass likely has a minimal impact on postmortem interval estimation.     

Site‐, Technique‐, and Time‐Related Aspects of the Postmortem Redistribution of Diazepam,Methadone, Morphine,and their Metabolites: Interest of Popliteal Vein Blood Sampling

Sampling site, technique, and time influence postmortem drug concentrations. In 57 cases, we studied drug concentration differences as follows: subclavian vein‐dissection/clamping versus blind stick, femoral vein‐dissection/clamping versus blind stick, right cardiac chamber, and popliteal vein‐dissection and clamping only. Cases were distributed in group #1 (all cases with both techniques), group #2 (dissection/clamping), and group #3 (blind stick). Sampled drugs were diazepam, methadone, morphine, and their metabolites. To assess PMR, mean concentrations and ratios were calculated for each group. Time‐dependent variations of blood concentrations and ratios were also assessed. Results indicate that site, method, and time may influence postmortem distribution interpretation in different ways. Popliteal blood seems less subject to PMR. In conclusion, our study is the first to evaluate concurrently three main aspects of PMR and confirms that the popliteal vein may represent a site that is more resistant to the changes seen as a result of PMR.     

Evaluation of the Role of Toxicological Data in Discriminating Between H2S Femoral Blood Concentration Secondary to Lethal poisoning and Endogenous H2S Putrefactive Production

Hydrogen sulfide is a colorless gas and has a strong odor of rotten eggs. It is absorbed by the upper respiratory tract mucosa, and it causes histotoxic hypoxemia and respiratory depression by exerting an inhibitory effect on cytochrome oxidase. To evaluate the role of toxicological data in distinguishing between the H₂S blood concentration secondary to lethal poisoning and the endogenous H₂S produced during putrefaction, we compared the postmortem H₂S concentrations of six fatal H₂S poisoning cases (8.7–28.6 mg/L) with the postmortem concentrations of endogenous H₂S of 12 subjects who died from other causes (traffic‐related deaths) (2.2–32.7 mg/L). These results will be of interest to the forensic community as it underlines the importance of considering circumstantial evidence along with the toxicological and pathological findings in the identification of H₂S lethal poisoning.     

Testing a Novel 3D Printed Radiographic Imaging Device for Use in Forensic Odontology

There are specific challenges related to forensic dental radiology and difficulties in aligning X‐ray equipment to teeth of interest. Researchers used 3D printing to create a new device, the combined holding and aiming device (CHAD), to address the positioning limitations of current dental X‐ray devices. Participants (N = 24) used the CHAD, soft dental wax, and a modified external aiming device (MEAD) to determine device preference, radiographer's efficiency, and technique errors. Each participant exposed six X‐rays per device for a total of 432 X‐rays scored. A significant difference was found at the 0.05 level between the three devices (p = 0.0015), with the MEAD having the least amount of total errors and soft dental wax taking the least amount of time. Total errors were highest when participants used soft dental wax—both the MEAD and the CHAD performed best overall. Further research in forensic dental radiology and use of holding devices is needed.