大鼠脑损伤分级自由落体打击模型的建立

目的建立一个控制性与重复性好,并可分级的脑损伤动物模型。方法根据自由落体原理,使击锤从不同的高度下落,造成轻、中、重不同程度的大鼠脑损伤,肉眼、光镜观察损伤的程度。结果肉眼、光镜观察下出现可分级的病理学改变。轻度损伤组病理改变局限于大鼠大脑皮质浅层,中度损伤组病理改变可见于大脑皮质及深部白质内的基底核、海马、胼胝体、丘脑,重度损伤组病理改变除中度损伤累及部位外,还累及脑干。挫伤灶周围神经元变性、坏死范围和程度随损伤程度的加重而增大。各组内每只动物所受损伤程度一致。结论该模型制作出常见的闭合性颅脑加速伤损伤,致伤程度较一致,重复性好,可分级,是脑损伤实验研究较合适的动物模型。     

实验性心脏挫伤动物模型的建立

本研究应用自制机械式弹性拉力打击器以9．1～10．5m／s速度冲击动物胸骨心前区，不仅导致左右心室压力、心电图及心率发生改变，而且造成了心脏挫伤等宏观的病理形态学变化，成功地建立了心脏挫伤动物模型，为深入研究钝力性心脏外伤奠定了基础。     

大鼠骨骼肌挫伤后细胞间黏附分子-1mRNA表达变化

目的应用荧光原位杂交（fluorescence in situ hybridization,FISH）技术检测大鼠骨骼肌挫伤后细胞间黏附分子-1（intercellular adhesion molecular—1,ICAM-1）mRNA表达。分析其与挫伤时间的关系。方法建立大鼠骨骼肌挫伤模型．分别取伤后0．5、1、6、12、18、24、30h及对照组检材。检材冰冻切片后进行FISH．激光共聚焦显微镜观察。结果大鼠骨骼肌挫伤后ICAM-1mRNA的表达6h达到峰值,18h下降至对照组的3．46倍．随后继续升高。结论大鼠骨骼肌挫伤后30h内ICAM—1mRNA的表达有一定的时间规律性．可望作为推断骨骼肌早期损伤时间的指标之一。     

实验性早期心肌挫伤的免疫组织化学研究

应用机械式弹性拉力打击器，以10．0m／s速度冲击犬胸骨心前区，建立免疫组织化学染色对伤后2～5分钟、30～60分钟、3小时及5小时心肌挫伤组织中Mb、CK－BB及CK－MM的变化进行观察。结果表明：（1）心肌挫伤后2～5分钟检出心内膜下肌层已有重度心肌Mb脱失及中度CK－BB、CK－MM脱失，并沉积于心肌纤维间，同时吸收入血。随着伤后时间延长，挫伤区三种物质脱失加重，但间质中沉积量减少乃至消失；（2）波浪变心肌中也可见三种物质的轻度脱失；（3）同一心脏中不同部位心肌的损伤程度不同、证明应用免疫组织化学染色技术可发现心肌挫伤性损害。心前区受到相当程度的钝力冲击后心脏不同部位损害程度不同。     

“烟雾病”法医学鉴定1例

1案例 某女，34岁，某日与他人发生争执后被打一记耳光，晕倒在地，即刻被送至医院。检查：BP220／130mmHg（29．3／17．3kPa），神志不清，浅昏迷，左侧瞳孔直径1．5mm，右侧瞳孔直径2mm，对光反射消失。颈软，四肢肌张力高，右下肢病理征（＋）。1h后查BP140／80mmHg（18．7／10．7kPa）。头颅CT示左侧基底节区出血，破入脑室。入院后查体：神志不清，GCS6分，查体不合作，双侧瞳孔等大等圆，对光反射消失，四肢肌张力高，左侧肢体肌力5级，右侧肢体肌力2级。     

钝力冲击后心脏组织形态学变化的实验研究

本研究用自制机械式弹性拉力打击器以６．７ｍ／ｓ、８．０ｍ／ｓ、９．１ｍ／ｓ及１０．０ｍ／ｓ速度冲击大胸骨心前区，然后采用多种组织学染色及透射电镜技术对心脏组织形态学变化进行了观察。结果表明：①以６．７ｍ／ｓ及８．０ｍ／ｓ速度冲击后心脏宏观未见有明显改变，微观可见心肌波浪变。电镜下可见肌原纤维肌节收缩，Ｉ带消失或轻度Ｉ带增宽乃至肌原纤维断裂。②以９．１ｍ／ｓ及１０．０ｍ／ｓ速度冲击后宏观可见心脏挫伤，微观心肌挫伤改变明显，实验观察６０ｍｉｎ内心肌血管内皮损伤处已有血小板粘附集聚甚至血栓形成，心肌超微结构损害严重。③同一心脏可有多部位损伤，且损伤程度不均一。本研究进一步表明钝力性心脏外伤中．虽然无宏观损伤所见，其微观，特别是超微结构可有损害。     

大鼠挫伤骨骼肌中M1/M2型巨噬细胞时间相关性研究

目的研究大鼠骨骼肌挫伤后M1/M2型巨噬细胞浸润的动态变化规律结合组织学改变建立损伤时间推断方法。方法建立大鼠骨骼肌挫伤模型,挫伤后6h、12h、24h、36h、48h、60h、72h、96h、144h、216h、336h为实验组,对照组不进行任何处理。采用HE染色法和免疫荧光多重染色方法观察骨骼肌挫伤后修复规律,运用全景组织细胞定量分析系统检测损伤区内单位面积细胞核数量、M1及M2型巨噬细胞数量和比例变化规律并建立与损伤时间的关系。结果在0.5mm×0.5mm范围内,M1型巨噬细胞比例在0.05±0.02~0.18±0.12且M2型巨噬细胞比例在0.02±0.01~0.04±0.02范围内时,推断该组织的损伤时间为伤后6h~48h;M1型巨噬细胞比例0.22±0.02且M2型巨噬细胞比例在0.09±0.02范围内时,推断该组织的损伤时间为损伤后60h;M1型巨噬细胞比例0.1±0.02且M2型巨噬细胞比例在0.16±0.07范围内时,推断该组织的损伤时间为损伤后144h;M1型巨噬细胞比例0.05±0.01~0.09±0.02且M2型巨噬细胞比例在0.07±0.02~0.09±0.01范围内时,推断该组织的损伤时间为损伤后216h~336h。结论大鼠挫伤骨骼肌中M1/M2型巨噬细胞时间相关性表达规律可作为损伤时间推断的新依据,结合病理组织学改变可进一步提高损伤时间推断的准确性。     

大鼠尺神经的损伤修复对其支配的爪内骨骼肌形态学改变的影响

目的通过对大鼠尺神经不同损伤断面和不同修复时间的实验研究．观察其支配的爪内骨骼肌形态学的改变,探讨法医临床学对尺神经损伤鉴定的最佳时机。方法选用SD大鼠42只．建立尺神经损伤修复模型,取爪内骨骼肌称量湿重,经HE和Masson染色,测量肌肉湿重、肌细胞横截面积和胶原纤维占肌纤维截面积的比率。结果（1）尺神经损伤后早期修复组的爪内骨骼肌萎缩程度均低于实验对照组．且即刻修复组比1个月修复组爪内骨骼肌功能恢复效果好。（2）失尺神经支配后爪内骨骼肌中的胶原纤维逐渐增多。（3）腕部与肘部尺神经损伤后,在相同时间修复尺神经,爪内骨骼肌萎缩的变化规律一致。结论尺神经损伤即刻修复能完全恢复爪内骨骼肌形态学改变,1个月修复能部分恢复其形态学改变．3个月修复则无法恢复其形态学改变;爪内骨骼肌中胶原纤维的增多是影响手术疗效和功能恢复的可能性原因之一;腕部与肘部的尺神经损伤修复对爪内骨骼肌形态学改变的影响无明显差异。     

大鼠死后肌动蛋白降解与死亡时间的相关性

目的观察大鼠死后不同时间心肌、肝、脾、肺、肾、脑和骨骼肌肌动蛋白（actin）的降解规律,为晚期死亡时间（postmortem interval,PMI）的推断寻找客观指标。方法28只SD大鼠随机分为7组,经机械性窒息致死后．分别置于20℃恒温箱内,于0、24、48、72、96、120和168h后剖取以上器官,应用免疫印迹技术检测各组织内actin的含量,SPSS11．5软件对所得数据进行方差分析。结果大鼠死后上述各器官actin含量均随PMI的延长而逐渐下降,与PMI相关,决定系数（R2）均在0．75以上。但actin在上述各器官内的降解速度有显著差异（P〈O．05）,在脑组织中降解速度最快,其余依次为肺、脾、肝、肾、心肌和骨骼肌。结论尽管大鼠死后心肌、肝、脾、肺、肾、脑和骨骼肌actin的降解规律具有组织差异性,但是actin在上述组织中的含量变化与PMI相关．有助于较晚期PMI的推断。     

实验性脑挫伤GFAP,PCNA免疫组织化学研究

采用改进的Ｆｅｅｎｅｙ氏落体打击致Ｗｉｓｔａｒ大鼠脑挫伤模型,利用免疫组织化学染色,观察大鼠实验性脑挫伤后ＧＦＡＰ、ＰＣＮＡ的改变,用图像分析仪对免疫组化染色阳性细胞灰度和面积进行测量,ＳＡＳ统计软件分析,得出脑挫伤后ＧＦＡＰ、ＰＣＮＡ变化的时间规律性,为脑挫伤形成时间推断提供新的手段。ＧＦＡＰ阳性细胞面积和灰度伤后呈上升趋势,伤后３ｈ,即有显著增加（Ｐ＜０．０１）,至４天时,阳性细胞灰度,面积达到峰值（Ｐ＜０．０１）,伤后７天仍保持较高水平（Ｐ＜０．０１）。ＰＣＮＡ阳性细胞伤后１２ｈ出现,灰度呈上升趋势,面积呈下降趋势,伤后３天时达到最大值（Ｐ＜０．０１）。因此,ＧＦＡＰ、ＰＣＮＡ免疫组织化学染色阳性细胞的数量,灰度,面积改变有时间性规律;推断２～７天的脑挫伤则以ＧＦＡＰ、ＰＣＮＡ改变为主;脑挫伤后星形胶质细胞数目增多,只有很少一部分为星形胶质细胞增殖而来,且这种增殖在伤后３天时达到高峰     

Ballistic skin simulant

Hydrogels prepared from water solutions containing 10-20 mass% gelatine are generally accepted muscle tissue simulants in terminal ballistic research. They, however, do not have a surface layer which simulates the effect of human skin. The purpose of this research was to find a suitable skin simulant for enhancing the testing fidelity and the credibility of the results with gelatine-based materials when assessing the injury potential of not only high energy bullets, but also especially that of non-penetrating "less lethal" kinetic impact ammunition and relatively low energy ricochet fragments. A skin simulant also permits the simulation and assessment of exit wounds. The mechanical and ballistic properties of human skin and target simulant were established on the basis of results found in the literature. Some errors in these were found. The corrected values are included in this paper for comparison. The target values of the mechanical properties of the skin simulant were the following: threshold velocity v(th)=94+/-4 m/s, tensile strength 18+/-2 N/mm2 and elongation at break 65+/-5%. A selection of synthetic and natural materials was evaluated as skin simulants by analysing their mechanical and ballistic properties. The results were compared to literature values obtained with human cadavers. The tests showed that the best skin simulant of the ones evaluated was semi-finished chrome tanned upholstery "crust" cowhide of 0.9-1.1 mm nominal thickness. Its threshold velocity was 90.7 m/s, tensile strength 20.89+/-4.11 MPa and elongation at break 61+/-9%. These values are the same as the average values of human skin. Of the synthetic materials evaluated, 1mm thick natural rubber can be used on impact side as a threshold velocity filter with some reservations although its theoretical threshold velocity is only 82.9 m/s.     

Injuries of the Head from Backface Deformation of Ballistic Protective Helmets Under Ballistic Impact

Modern ballistic helmets defeat penetrating bullets by energy transfer from the projectile to the helmet, producing helmet deformation. This deformation may cause severe injuries without completely perforating the helmet, termed “behind armor blunt trauma” (BABT). As helmets become lighter, the likelihood of larger helmet backface deformation under ballistic impact increases. To characterize the potential for BABT, seven postmortem human head/neck specimens wearing a ballistic protective helmet were exposed to nonperforating impact, using a 9 mm, full metal jacket, 124 grain bullet with velocities of 400–460 m/s. An increasing trend of injury severity was observed, ranging from simple linear fractures to combinations of linear and depressed fractures. Overall, the ability to identify skull fractures resulting from BABT can be used in forensic investigations. Our results demonstrate a high risk of skull fracture due to BABT and necessitate the prevention of BABT as a design factor in future generations of protective gear.     

Freezing skeletal muscle tissue does not affect its decomposition in soil: Evidence from temporal changes in tissue mass,microbial activity and soil chemistry based on excised samples

The study of decaying organisms and death assemblages is referred to as forensic taphonomy, or more simply the study of graves. This field is dominated by the fields of entomology, anthropology and archaeology. Forensic taphonomy also includes the study of the ecology and chemistry of the burial environment. Studies in forensic taphonomy often require the use of analogues for human cadavers or their component parts. These might include animal cadavers or skeletal muscle tissue. However, sufficient supplies of cadavers or analogues may require periodic freezing of test material prior to experimental inhumation in the soil. This study was carried out to ascertain the effect of freezing on skeletal muscle tissue prior to inhumation and decomposition in a soil environment under controlled laboratory conditions. Changes in soil chemistry were also measured. In order to test the impact of freezing, skeletal muscle tissue (Sus scrofa) was frozen (?20 °C) or refrigerated (4 °C). Portions of skeletal muscle tissue (～1.5 g) were interred in microcosms (72 mm diameter × 120 mm height) containing sieved (2 mm) soil (sand) adjusted to 50% water holding capacity. The experiment had three treatments: control with no skeletal muscle tissue, microcosms containing frozen skeletal muscle tissue and those containing refrigerated tissue. The microcosms were destructively harvested at sequential periods of 2, 4, 6, 8, 12, 16, 23, 30 and 37 days after interment of skeletal muscle tissue. These harvests were replicated 6 times for each treatment. Microbial activity (carbon dioxide respiration) was monitored throughout the experiment. At harvest the skeletal muscle tissue was removed and the detritosphere soil was sampled for chemical analysis. Freezing was found to have no significant impact on decomposition or soil chemistry compared to unfrozen samples in the current study using skeletal muscle tissue. However, the interment of skeletal muscle tissue had a significant impact on the microbial activity (carbon dioxide respiration) and chemistry of the surrounding soil including: pH, electroconductivity, ammonium, nitrate, phosphate and potassium. This is the first laboratory controlled study to measure changes in inorganic chemistry in soil associated with the decomposition of skeletal muscle tissue in combination with microbial activity.     

Diverse morphological lesions and serious arrhythmias with hemodynamic insults occur in the early myocardial contusion due to blunt impact in dogs

To investigate the morphology and hemodynamics of the early myocardial contusion, an animal model of cardiac contusion was established by impact to the precordial region at sternum at velocity of 10.0m/s with a mechanical elastic-cord propelled impactor in 19 dogs. The electrocardiogram and both the left and right intra-ventricular pressures were recorded continuously throughout the experiment. Histological and immunohistochemical examinations of myoglobin, creatine kinase-MB and fibrinogen were conducted. At the moment of impact, abrupt over-pressures within the left and right ventricles occurred with concomitant serious arrhythmias followed by variety of cardiac conduction disorders and depressed left and right ventricular systolic pressures during the observation times. Histologically, lesions of myocardial contusions were identified at subepicardial, myocardial or subendocardial layer as interstitial hemorrhage, disruption or coagulative necrosis as well as contraction band necrosis of the muscle fibers, which might be categorized into the hemorrhagic, necrotized and mixed forms. The three forms of lesions were found to exist independently, or co-existed in a heart. However, severity of the lesions varied greatly with different parts even within a heart. Intravascular thromboses were occasionally discovered post-impact. Immunohistochemically, loss of myoglobin and creatine kinase-MB from cardiac cells, and accumulation of fibrinogen at the cell membranes were detected 5min post-impact. The intracellular accumulation of fibrinogen increased with extension of post-impact intervals. Our results indicate that diverse morphological lesions concomitant with hemodynamic compromise and serious, even fatal arrhythmias occur in the early myocardial contusion, and intravascular thromboses are occasionally produced, suggesting that traumatic myocardial ischemic lesion may be induced due to blunt impact to the precordial region.     

Injuries and Health Care Use in Women with Partners in Batterer Intervention Programs

Objective:To characterize injury frequency, injury patterns, and health care seeking behavior in women with intimate partners enrolled in batterer intervention programs. Methods: A standardized telephone interview was conducted on a sample of women with male partners enrolled in batterer intervention programs in four U.S. cities. Information on prior injuries and the utilization of health care services was sought. Results: Four hundred and eighty eight of the 648 women (75.3%) reported a history of prior injury as a result of abuse. Contusions were the most common injury. Of the women reporting contusions, 233 (51.4%) reported contusions as their only injuries. Another 220 women (48.6%) reported other injuries in addition to contusions. In the majority of cases (63.2%) the contusions were to multiple body parts. When the contusion involved only one anatomical region, it was mostly to the face. A total of 192 of the 488 injured women (39.3%) reported ever seeking medical care for injuries caused by their intimate partner. Twenty-three women (4.7% of the injured cohort or 3.5% of the total cohort) reported having ever been hospitalized for injuries sustained from abuse.     

Commotio cordis, revisited

Nonpenetrating cardiac injuries due to direct precordial blunt impacts are a commonly encountered phenomenon in medicolegal offices. These injuries vary from contusions to valvular lacerations, or papillary muscle rupture to coronary arterial injury with resulting infarction. A less commonly occurring manifestation of nonpenetrating injury is a concussion of the heart (commotio cordis), often with dramatic physiological consequences but no morphologic cardiac injury. We describe four case reports of this entity. The cases were collected over a 5-year period (1978-1983) from the Wayne County Medical Examiner's Office in Detroit, Michigan.     

Deducing drop size and impact velocity from circular bloodstains

An experimental study was done to determine the diameter and velocity of blood drops falling on a surface by measuring the size of bloodstains they produced and counting the number of radial spines projecting from them. Bloodstains were formed by releasing drops of pig blood with a range of diameters (3.0-4.3 mm) and impact velocities (2.4-4.9 m/s), onto four different flat surfaces (glass, steel, plastic, paper) with varying roughness (0.03-2.9 microm). High-speed photography was used to record drop impact dynamics. Bloodstain diameters and the number of spines formed around the rim of stains increased with impact velocity and drop diameter. Increasing surface roughness reduced stain diameter and promoted merging of spines, diminishing their number. Equations are presented that explicitly relate drop diameter and impact velocity to measurements of stain diameter and number of spines.     

Frequency and severity of injuries in correlation with the height of fall

The main aim of this study was to examine the correlation between the height of fall and the frequency, extensiveness, and type of injuries of certain body regions and organs. The specific objective was to determine characteristic injuries of the analyzed body regions in relation to the certain height of fall. The study included 660 cases of fatal falls from height (469 males and 191 females). Results support the hypothesis that the frequency and extent of the injured body regions and organs are related to the fall height. Head injuries are characteristic of the falls from heights up to 7 m and beyond 30 m. Brain injuries in high falls from heights beyond 30 m show an absence of contre coup contusions and macroscopically evident intracranial bleeding. The extensiveness of chest injuries is significantly statistically associated with fall height. In cases of high falls, the frequency of abdominal injuries is not significantly statistically related to the height of fall. Liver injuries are the most common abdominal injury and the critical height of fall at which the liver injury occurs is 15 m. Injuries of liver and spleen are concomitant in high falls from heights beyond 24 m, irrespective of the manner of impact. The height of fall over 15 m appears to be a reasonable boundary height beyond which the injuries of two or three body regions are generally associated.