Bite marks: physical properties of ring adhesion to skin-phase 1

Abstract: Unsupported excised skin may shrink by as much as 50% or more. In 1981, a method was developed for ring adhesion to skin with the goal of minimizing tissue distortion upon excision. Five modified versions of the technique bearing the author’s name followed (Dorion types I, II, III, IV, and V). The scientific literature reveals little supporting empirical evidence for the preferential use of one adhesive/suturing technique over another. This study compares the use of various bonding materials (Loctite Super Glue gel^®, Dermabond?, Vetbond?), cleaning agents (ethanol, dishwashing liquid, and shaving cream), and depilatory (Veet^®) on the effects of ring adhesion to skin. The conclusions indicate that surface wetness is the most influential factor affecting ring adhesion to skin, followed by the type of bonding material, its “freshness,” and by the cleaning agent used to prepare the skin. The use of a depilatory or shaving cream is to be avoided.     

An Unusual Zip Gun Suicide—Medicolegal and Ballistic Examination

Abstract:  Home-made guns are imitations of typical firearms and usually have handgun characteristics. This article presents an unusual case of a suicide carried out by means of a fatal gunshot wound to the head using a home-made zip gun. A 49-year-old male, with a history of paranoid psychosis was found dead in the dwelling place of a family house. The investigation at the crime scene did not lead to suspicion of a gunshot wound because of the unusual nature of the firearm used. A medical examiner diagnosed an opened head injury as the primary cause of the victim's death. The autopsy findings provided immediate grounds for further inspection of the crime scene. Subsequently, a simple zip gun, which had been overlooked during the scene investigation, was discovered. An undeformed projectile recovered from the victim's head was consistent with the use of the home-made firearm. Following the completion of the investigations and autopsy, the death was classified as a suicide.     

Evaluation of Skin Surface as an Alternative Source of Reference DNA Samples: A Pilot Study

An acceptable area for collecting DNA reference sample is a part of the forensic DNA analysis development. The aim of this study was to evaluate skin surface cells (SSC) as an alternate source of reference DNA sample. From each volunteer (n = 10), six samples from skin surface areas (forearm and fingertips) and two traditional samples (blood and buccal cells) were collected. Genomic DNA was extracted and quantified then genotyped using standard techniques. The highest DNA concentration of SSC samples was collected using the tape/forearm method of collection (2.1 ng/μL). Cotton swabs moistened with ethanol yielded higher quantities of DNA than swabs moistened with salicylic acid, and it gave the highest percentage of full STR profiles (97%). This study supports the use of SSC as a noninvasive sampling technique and as a extremely useful source of DNA reference samples among certain cultures where the use of buccal swabs can be considered socially unacceptable.     

应用Pixel法测量平面内非直线长度的法医学研究

目的探寻一种法医鉴定工作中测量平面内非直线长度的方法。方法精确切断长度不同的10根焊接锡丝并读出结果作为对照组(钢尺直接读取法),再分别将这10根长度不同的焊接锡丝任意弯曲,然后用本文研究的方法计算出长度作为Pixel组,并对两组数据进行统计学分析。结果 Pixel方法得出的结果与钢尺读取法直接读出的结果之间的差异不具有统计学意义。结论 Pixel法在测量平面内非直线长度(如瘢痕、创口)上比传统的棉线法有明显优势,计算出来的长度更精确、易操作,使法医学鉴定结论更准确、有说服力,也更能适应诉讼要求,在法医学鉴定中有很好的应用前景。     

皮肤烧伤愈合过程中磷酸化c-Jun的表达

目的观察烧伤后人皮肤磷酸化c-Jun(p-c-Jun)的变化特点,初步探讨烧伤后创面愈合的分子机制。方法取12例烧伤后住院植皮患者的烧伤周边区皮肤为实验组;另取正常皮肤12例为对照组。应用免疫组织化学方法和常规HE染色检测p-c-Jun在皮肤烧伤周边区和正常皮肤组织中的变化情况。结果对照组p-c-Jun阳性颗粒主要定位于表皮细胞和内皮细胞中,阳性细胞率为(13.9±2.7)%;实验组p-c-Jun阳性颗粒主要定位于表皮细胞和部分炎细胞中,阳性细胞率上升至(47.2±8.6)%,明显高于对照组(P0.01)。结论烧伤后人皮肤p-c-Jun的表达可能与创面愈合有关。     

Enhancing the Visibility of Injuries with Narrow‐Banded Beams of Light within the Visible Light Spectrum

The use of narrow‐banded visible light sources in improving the visibility of injuries has been hardly investigated, and studies examining the extent of this improvement are lacking. In this study, narrow‐banded beams of light within the visible light spectrum were used to explore their ability in improving the visibility of external injuries. The beams of light were induced by four crime‐lites^® providing narrow‐banded beams of light between 400 and 550 nm. The visibility of the injuries was assessed through specific long‐pass filters supplied with the set of crime‐lites^®. Forty‐three percent of the examined injuries improved in visibility by using the narrow‐banded visible light. In addition, injuries were visualized that were not visible or just barely visible to the naked eye. The improvements in visibility were particularly marked with the use of crime‐lites^® “violet” and “blue” covering the spectrum between 400–430 and 430–470 nm. The simple noninvasive method showed a great potential contribution in injury examination.     

The Survival of Gunshot Residues in Cremated Bone: An Inductively Coupled Plasma Optical Emission Spectrometry Study

Gunshot residue (GSR) has been sought and demonstrated on many types of material and with many techniques. Inductively coupled plasma optical emission spectrometry (ICP‐OES) could be a useful method on difficult substrates, but a systematic study on burnt material has never been performed. Hence, this study aims at evaluating the usefulness and reliability of this method on burnt samples. Sixteen adult bovine ribs (eight with soft tissues, eight totally skeletonized) were shot using two kinds of projectile (both 9 mm full metal‐jacketed or unjacketed). Then, every sample was led to complete calcination in an electric oven. The area of the gunshot entrance wound was swabbed and analyzed by ICP‐OES; the results were also correlated with a previously published parallel study by scanning electron microscopy (SEM) equipped with an SEM–energy dispersive X‐ray analyzer. ICP‐OES proved to be very sensitive and reliable even on degraded material and can be an appropriate nondestructive method for detecting residues on difficult and delicate substrates such as burnt bone.     

兔急性肺损伤后肺内VEGF时序性表达的研究

目的观察大潮气量机械通气致兔急性肺损伤(acutelung injury,ALI)后,肺组织中血管内皮生长因子(VEGF)的动态变化,探讨其在损伤时间推断中应用的价值。方法57只雄性新西兰大白兔随机分为正常组(3只)、对照组(27只)和实验组(27只)。机械通气(V_T 60mL/kg)致AL后于0,1,3,6,12,18,24,36,48h各处死动物3只。取肺组织,测量右上肺组织湿干重比(W/D),肺组织进行HE及免疫组织化学染色并进行图像定量分析,观察VEGF变化规律。结果正常组VEGF有低水平表达;大潮气量机械通气1min后至肺损伤后12h,实验组VEGF表达水平与正常组无明显差异(P>0.05);12～48h随损伤时间的延长VEGF表达水平持续上升,48h仍处于较高水平,其间各时间点VEGF表达水平与正常组比较均有显著性差异(P<0.05)。结论大潮气量机械通气致兔ALI 2d内,VEGF在肺组织炎症发生、发展和愈合修复过程中存在时间相关性,对法医病理推断呼吸机所致的ALI时间具有参考价值。     

大鼠皮肤切创后E-选择素表达及稳定性研究

目的探讨大鼠皮肤切创后E-选择素表达规律及法医学意义。方法健康SD大鼠90只,随机分成4组：正常对照组、活体切创组（30min～7d12个时间点）、死后切创组（30min～3h3个时间点）、死后稳定性组（-20％6h-7d9个时间点,25％6h～3d5个时间点）。在大鼠头部建立皮肤切创模型,按设定的时间点取皮肤检材,运用免疫组化和图像分析技术,检测血管内皮E-选择素的表达规律。结果在活体切创组中,伤后1hE-选择素在血管内皮细胞内即呈阳性表达,持续至伤后7d,且随时间变化呈规律性表达。在正常对照及死后切创组未见阳性表达。死后-20％稳定性组各时间点E-选择素表达与死后即刻比较无显著性差异（P〉0．05）。25％各时间点与死后即刻比较有显著性差异（P〈0．01）。结论E-选择素在创伤后血管内皮细胞内特异性的表达具有时序性规律,且低温条件下稳定性较好。     

Caspase3和iNOS在人挫伤脑组织中的时序性表达

目的研究人脑挫伤后不同时间半胱氨酸天冬氨酸蛋白酶3（caspase3）和诱导型一氧化氮合酶（inducible nitric oxide synthase,iNOS）表达的变化,为法医实践中脑损伤时间的推断提供依据。方法选择30例因颅脑损伤死亡案例为损伤组,5例非颅脑损伤急死的案例为对照组,应用免疫组织化学和图像分析技术,分别于死亡后2h、4～8h、10～14h、1～2d、3～5d及8～11d检测脑组织标本中caspase3和iNOS的变化规律。结果经统计学分析：（1）caspase3阳性细胞表达在伤后2h以内组开始升高,与对照组相比差异有统计学意义（P〈0.05）,1～2d组表达强度增高,3～5d组仍见高表达（P〈0.05）,以后逐渐下降。（2）iNOS阳性细胞表达在2h以内组与对照组比较差异无统计学意义（P〉0.05）,伤后4～8h开始升高（P〈0.05）,1～2d组表达强度最高,以后逐渐下降,伤后8～11d仍有弱表达（P〈0.05）。结论caspase3和iNOS的表达可能成为实际检案中脑损伤时间推断的有效依据。