采用无创性核磁共振技术进行损伤时间推断初探

目的建立大鼠皮肤损伤核磁共振（nuclear magnetic resonance,NMR）检测方法,探讨其在法医学中应用的意义。方法雄性SD大鼠36只,随机分为皮肤切创和挫伤组,分别在大鼠背部制作皮肤切创和挫伤,各组分别在损伤后0h、4h、8h取皮肤组织及对侧无损伤部位皮肤,检测NMR一维1H谱,观察受创皮肤的分子代谢产物随损伤时间的变化规律。结果挫伤组、切创组背部损伤处皮肤的1H-NMR图谱在损伤后4h和8h分别检测到较多NMR波峰,波峰的高度和总面积也发生了改变,与对照部位皮肤相比,存在显著性差异（P〈0.05）。结论核磁共振技术检测组织代谢产物有望用于损伤经过时间的法医学检验。     

不同温度下大鼠皮肤5种RNA指标与PMI的相关性

目的探讨大鼠皮肤内β-肌动蛋白(β-actin)、甘油醛-3-磷酸脱氢酶(glyceraldehyde-3-phosphate dehydrogenase,GAPDH)、18S核糖体RNA(18S ribosomal RNA,18S rRNA)、5S核糖体RNA(5S ribosomal RNA,5S rRNA)以及微小RNA-203(microRNA-203,miR-203)这5种RNA指标在不同温度下的表达水平与死亡时间(PMI)的相关性。方法将18只SD大鼠随机分为3组,处死后分别置于4℃、15℃和35℃的环境中,于死后0~120h内11个时间点取大鼠腹部皮肤。抽提皮肤总RNA,利用实时荧光定量PCR技术检测5种RNA表达水平。运用geNorm软件选取合适内参后,利用GraphPad软件对内参标准化的RNA指标进行回归分析。结果 5S rRNA和miR-203作为内参最合适。在4℃和15℃温度组中,β-actin和GAPDH的表达量变化与PMI线性关系良好。在35℃下,β-actin和GAPDH与PMI呈现S形曲线关系。而18S rRNA只在15℃和35℃温度组呈现一定的线性关系。结论皮肤组织比较适合作为提取RNA的检材,其中β-actin和GAPDH表达水平与PMI相关性良好,有望成为推测PMI的辅助指标。     

Quantifying the Temperature of Maggot Masses and its Relationship to Decomposition

Numerous Calliphoridae species have been observed to form larval aggregations during the feeding stage of development, resulting in localized increases in temperature. This study investigates the relationship between maggot numbers in a mass and heat generation. Single‐species aggregations (Lucilia sericata) of various sizes (50–2500 individuals) were reared in the laboratory at a constant ambient temperature of 22°C. Internal mass temperatures were recorded every 5 min throughout the feeding stage of development. Results showed that mass temperatures increased with mass numbers (p‐value < 0.001), ranging from 2.5 to 14°C above ambient. A minimum mass size of 1200 produced overall temperatures that were significantly warmer than ambient, diverging away from 22°C after c. 26 h. These results indicate that the microclimate of a mass has the potential to differ significantly from ambient, which may be influencing larval development rates and should therefore be factored into mPMI estimates to increase accuracy.     

Identification of Crystals Forming on Porcine Articular Cartilage: A New Method for the Estimation of the Postmortem Interval

Articular cartilage was examined to determine its decomposition sequence and its potential for assessing the postmortem interval. Scanning electron microscopy of articular cartilage from buried porcine trotters showed the presence of microcrystals on the synovial surface. These orthorhombic pyramidal or “coffin”‐shaped crystals, appeared at 3 weeks (22 days) after interment and disappeared after 6 weeks. The disappearance of these crystals was linked to decompositional changes to the integrity of the synovial joint. The formation and disappearance of these crystals was associated with a pH change at the cartilage surface. Scanning electron microscopy–energy‐dispersive X‐ray (SEM‐EDX) analysis showed that the five main elements contained within these crystals were carbon, nitrogen, oxygen, magnesium, and phosphorous. Such elemental analysis suggested the crystals may be struvite (MgNH₄PO₄6(H₂O)). Bacteria cultured from the cartilage synovial surface produced struvite crystals when grown in suitable media and were identified by DNA analysis to be Comamonas sp.     

Investigation into the merits of infrared imaging in the investigation of tattoos postmortem

Infrared imaging has a history of use in the forensic examination of artwork and documents and is investigated here for its wider use in the detection of tattoos on the human body postmortem. Infrared photographic and reflectographic techniques were tested on 18 living individuals, displaying a total of 30 tattoos. It was observed that neither age, sex, age of the tattoo, nor, most significantly, skin color affected the ability to image the tattoos using infrared imaging techniques. Second, a piglet carcass was tattooed and the impact of the decomposition process on the visibility of the tattoos assessed. Changes were recorded for 17 days and decomposition included partial mummification and skin discoloration. Crucially, the discoloration was recorded as greatly affecting the image quality using conventional photography, but was insignificant to the infrared recording of these tattoos. It was concluded that infrared reflectography was beneficial in the investigation into tattoos postmortem.     

A Study of the Human Decomposition Sequence in Central Texas*

Abstract: Decomposition studies utilizing nonhuman subjects as human analogues are well established, but fewer studies utilizing intact human remains exist. This study provides data from a controlled decomposition study involving human remains in Central Texas. A 63.5‐kg unmodified cadaver was placed in an open‐air site and observed over a 10‐week period from April 11 through June 19, 2008. A wire enclosure restricted scavenger access. State of decomposition and environmental conditions were recorded daily for the first 36 days and then every 2 weeks thereafter. Results indicated a high degree of correlation with other decomposition studies originating in the southwestern United States, although slight deviations for the average duration of early events were noted. The data were also utilized to test a quantitative method for estimating the postmortem interval. Results indicated preliminary support for a quantitative approach. Additional research is encouraged to further establish the human decomposition data set for Central Texas.     

Body scanners versus privacy and data protection

In recent history, the world has experienced dramatic events which have had a substantial effect on the balance between human rights protection and security measures. Body scanners installed at airports are intended to protect our lives. But at the same time they have a serious impact on privacy and data protection. The international legislation allows limiting people’s rights and freedoms, but only if it is in accordance with the law and is proportionate and necessary for national security, public safety and for the protection of the rights and freedoms of others. Do body scanners respect these principles? The article examines the current situation, its background and future prospects. It discusses and analyzes the key terms and legal instruments, problems, disputes and proposed “safeguards”. The work concludes by pointing out the unlawfulness of current regimes and sets forth perspective on the possible solutions.     

Increased adrenaline to noradrenaline ratio is a superior indicator of antemortem hypothermia compared with separate catecholamine concentrations

The significance of urinary catecholamines and small gastric mucosal bleedings, Wischnewsky's spots, in postmortem diagnosis of hypothermia deaths was evaluated. Autopsy cases (n=358) were divided into hypothermia, suspected hypothermia, and control groups. The catecholamine levels did not correlate with the length of the postmortem period. The adrenaline to noradrenaline ratio was most effective in detecting hypothermia (68.9% sensitivity, 78.1% specificity). The median adrenaline concentrations were significantly higher in hypothermia than in control groups. The control group containing mostly sudden cardiac deaths with no cold exposure had a noradrenaline level comparable to the hypothermia groups. The sensitivity and specificity of determining Wischnewsky's spots in hypothermia deaths were 63.9% and 88.3%, respectively. The adrenaline to noradrenaline ratio is more suitable in proving antemortem cold stress than either of these independently, and its diagnostic value is comparable to that of Wischnewsky's spots.     

Reverse engineering--rapid prototyping of the skull in forensic trauma analysis

Rapid prototyping (RP) comprises a variety of automated manufacturing techniques such as selective laser sintering (SLS), stereolithography, and three-dimensional printing (3DP), which use virtual 3D data sets to fabricate solid forms in a layer-by-layer technique. Despite a growing demand for (virtual) reconstruction models in daily forensic casework, maceration of the skull is frequently assigned to ensure haptic evidence presentation in the courtroom. Owing to the progress in the field of forensic radiology, 3D data sets of relevant cases are usually available to the forensic expert. Here, we present a first application of RP in forensic medicine using computed tomography scans for the fabrication of an SLS skull model in a case of fatal hammer impacts to the head. The report is intended to show that this method fully respects the dignity of the deceased and is consistent with medical ethics but nevertheless provides an excellent 3D impression of anatomical structures and injuries.     

In vivo facial tissue depth study of Chinese-American adults in New York City

This study examines facial tissue depth in adult Chinese-Americans. Using ultrasound, measurements were taken at 19 landmarks across the faces of 101 individuals aged from 18 to 87 years. Summary statistics are reported for a sample of 67 individuals of normal weight (as determined by a body mass index [BMI] of 19-25). Statistical analyses were used to assess relationships between tissue thickness, age, and BMI. Results indicate that no significant relationship exists between tissue thickness and age for males, and for only 3/19 points in females. Also, only four points showed significant relationships between tissue thickness and sex. However, significant relationships exist between BMI and tissue thickness at multiple points for both males and females. Compared to other American and Asian populations in the literature, Chinese-Americans generally had thinner facial tissue; though, this difference was not assessed statistically. Finally, data generated in this study will add to the body of knowledge concerning facial tissue depth variation in modern humans.