Research Progress and Forensic Application of Human Vascular Finite Element Modeling and Biomechanics.

The finite element method (FEM) is a mathematical method for obtaining approximate solutions to a wide variety of engineering problems. With the development of computer technology, it is gradually applied to the study of biomechanics of human body. The application of the combination of FEM and biomechanics in exploring the relationship between vascular injury and disease, and pathological mechanisms will be a technological innovation for traditional forensic medicine. This paper reviews the construction and development of human vascular FEM modeling, and its research progress on the vascular biomechanics. This paper also looks to the application prospects of FEM modeling in forensic pathology.

Forensic Pathological Diagnosis of Acute and Old Myocardial Infarction Using Fourier Transform Infrared Spectroscopy.

OBJECTIVES: Fourier transform infrared spectroscopy (FTIR) was used to analyze myocardial infarction tissues at different stages of pathological change to achieve the forensic pathology diagnosis of acute and old myocardial infarction. METHODS: FTIR spectra data of early ischemic myocardium, necrotic myocardium, and myocardial fibrous tissue in the left ventricular anterior wall of the sudden death group of atherosclerotic heart disease and the myocardium of the normal control group were collected using hematoxylin-eosin (HE) and immunohistochemistry (IHC) staining as a reference, and the data were analyzed using multivariate statistical analysis. RESULTS: The mean normalized spectra of control myocardium, early ischemic myocardium and necrotic myocardium were relatively similar, but the mean second derivative spectra were significantly different. The peak intensity of secondary structure of proteins in early ischemic myocardium was significantly higher than in other types of myocardium, and the peak intensity of the α-helix in necrotic myocardium was the lowest. The peaks of amide Ⅰ and amide Ⅱ in the mean normalized spectra of myocardial fibrous tissue significantly shifted towards higher wave numbers, the peak intensities of amide Ⅱ and amide Ⅲ were higher than those of other types of myocardium, and the peak intensities at 1 338, 1 284, 1 238 and 1 204 cm-1 in the mean second derivative spectra were significantly enhanced. Principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) showed that FTIR could distinguish different types of myocardium. CONCLUSIONS: FTIR technique has the potential to diagnose acute and old myocardial infarction, and provides a new basis for the analysis of the causes of sudden cardiac death.

Pulmonary PMCT angiography by right ventricle cardiac puncture: a novel, promising approach for investigating pulmonary thromboembolism.

Forensic scholars are paying more attention to postmortem computed tomography (PMCT) and PMCT angiography (PMCTA), which are gradually becoming effective and practical methods in forensic practice. However, few studies have focused on the application of PMCTA to cardiac ventricular puncture-especially of the right ventricle. In this article, we introduce a pulmonary PMCTA approach by right ventricle cardiac puncture and its potential value in fatalities from pulmonary thromboembolism (PTE). The procedure was performed on 11 males and 6 females. PMCT was performed first; then a biopsy core needle was used for percutaneous puncture of the right ventricle under CT guidance. About 400 mL of contrast media was injected at a rate of 50 mL/8 s, followed by CT scanning. Visualization of the pulmonary artery contrast filling was complete in 9 cadavers, and the pulmonary arteries showed significant filling defects in 8 subjects. Unlike in clinical practice, the phenomenon of postmortem coagulation sometimes occurs in the vascular lumina after death. Therefore, the results of these 8 cases can only suggest or be highly suspicious of death from PTE. Then autopsy and histopathological examination confirmed that 4 of the above 8 patients were diagnosed with PTE; the remaining 4 had postmortem clot including chicken fat clot in the pulmonary artery. Pulmonary PMCTA approach is a simple, convenient, and effective method for the visualization of the pulmonary artery, which can be used as an effective auxiliary tool to identify PTE in forensic practice. It will also provide technical support to further investigate PTE imaging characteristics.

[Comparison of Postmortem MSCT and Autopsy Findings in Traffic Accident Victims].

OBJECTIVE: To explore the application value of postmortem multi-slice spiral computed tomography (MSCT) by observing and analyzing the injury features in the traffic accident victims. METHODS: Ten traffic accident victims were scanned with whole body MSCT. The systemic autopsy was subsequently performed to compare with the results of MSCT. The advantages and disadvantages of autopsy and MSCT for obtaining the information of traffic accident injuries were then analyzed. RESULTS: MSCT could reveal 3D shape of fractures clearly and detect air accumulation in different positions of the body, which showed the obvious advantages compared with autopsy. However, the resolution of MSCT was limited compared to the detection of organ and soft tissue injuries. CONCLUSION: A combination of MSCT and autopsy is the best way for determining the manner and the cause of death in traffic fatality victims.

[Proteomic Analysis of Rat Brain Stem with DAI by MALDI-TOF-MS].

OBJECTIVE: To establish a diagnostic model for diffuse axonal injury (DAI) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). To screen the proteins or peptides associated with DAI for providing the biomarkers with theoretic foundation. METHODS: Fifteen male Sprague-Dawley rats were randomly divided into DAI group (n = 10) and control group (n = 5). The protein or peptide expression profiles of rat brain stem were detected by MALDI-TOF-MS. ClinProTools 2.2 software was used to find specific peaks, and a diagnostic model was established by the genetic algorithm. RESULTS: There were significant differences in 61 peaks of DAI group (P < 0.05), 9 peaks were down-regulated and 52 up-regulated. The diagnostic model was established based on 5 different peaks. The specificity and sensitivity of cross validation was 96.14% and 95.98%; while the specificity and sensitivity of blind validation showed was 73.33% and 70.00%, respectively. CONCLUSION: A specific and sensitive diagnostic model of DAI can be established by MALDI-TOF-MS to provide a potential value for determining DAI in forensic practice.

Determination of a Newborn with Lethal Type II Osteogenesis Imperfecta and Other Anomalies Using Autopsy and Postmortem MSCT--A Case Report.

A case of a stillbirth with lethal type II osteogenesis imperfecta (OI) was reported. The fetus had skull fractures and craniocerebral injuries during pregnancy. Postmortem multi-sliced computed tomography (MSCT) and 3D-reconstruction were performed, followed by a medico-legal autopsy. The autopsic findings showed the typical features of type II OI, including a soft calvarium, deformed extremities, flexed and abducted hips, and uncommon features, such as white sclera, coxa vara, absence of several bones and organs, a cleft lip, and asymmetric ears. The radiologic images revealed such anomalies and variations as a cleft palate, mandibular dysplasia, spina bifida, costa cervicalis, and fusion of the ribs and vertebrae, which were difficult to detect during conventional autopsy. The paper investigated the classification, causative mutation, cause of death, and the differentiation of OI from child abuse, coming to a conclusion that OI knowledge can be of great importance to forensic pathologists and that the merits of postmortem MSCT should be emphasized in forensic pathologic examinations.

[New Progress of MALDI-TOF-IMS in the Study of Proteomics].

Matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF-IMS) has been a classical technique for studying proteomics in present and a tool for analyzing the distribution of proteins and small molecules within biological tissue sections. MALDI-TOF-IMS can analyze multiple unknown compounds in biological tissue sections simultaneously through a single measurement which can obtain molecule imaging of the tissue while maintaining the integrity of cellular and molecules in tissue. In recent years, imaging mass spectrometry technique develops relatively quickly in all biomedical domain. This paper based on the relevant data and reviews the present developing level of MALDI-TOF-IMS, the principle of imaging mass spectrometry, methology and the prospect in forensic pathology.

[Postmortem MSCT Analysis and Identification of Fall from Height: One Case Report].

OBJECTIVE: To explore the application value of postmortem multi-slice spiral computed tomography (MSCT) in cases of fall from height through observing and analyzing the injury features of the fall and reconstructing the process of the fall based on the the above procedure. METHODS: One real fatal case due to fall from height was fully examined using MSCT and three-dimensional reconstruction technique. Analyzing the manner and cause of death through combination of MSCT and systemic autopsy was also implemented. The differences between autopsy and MSCT in getting information of injuries were compared. RESULTS: Fractures involving multiple body regions and liver rupture were found through MSCT and three-dimensional reconstruction. The autopsy got the same results with imageological examination. The case of death was deduced to be fall leading to systemic polytrauma. CONCLUSION: Application of MSCT can be used as the complimentary for traditional autopsy in the analysis of injury manner of fall from height.

[Whiplash injury analysis of cervical vertebra by finite element method].

Finite element method (FEM) is an effective mathematical method for stress analysis, and has been gradually applied in the study of biomechanics of human body structures. This paper reviews the construction, development, materials assignment and verification of FEM model of cervical vertebra, and it also states the research results of injury mechanism of whiplash injury and biomechanical response analysis of the cervical vertebra using FEM by researchers at home and abroad.

[Forensic Analysis of 33 Cases of Fatal Pulmonary Thromboembolism].

OBJECTIVE: To explore the related risk facts of pulmonary thromboembolism (PTE) and analyze the relation between PTE and the trauma or medical behavior by investigating the cases of PTE. METHODS: Thirty-three cases were selected from Institute of Forensic Science (IFS) from 2000 to 2014. RESULTS: In 33 cases, 16 decedents were male, 17 decedents were female; different degrees of dyspnea, chest tight- ness and syncope symptoms were the clinical manifestation of the deceased; the thrombus was mainly distributed in the left and right pulmonary arteries. The main source of embolism was the deep vein of lower limb and the left probability was higher. Trauma, limited position, operation and cardiovascular disease showed high-risk factors of PTE; D-Dimer test, hemolytic test and computer tomography pul- monary angiography were the diagnostic tools for PTE. In some cases, trauma and medical malpractice could be involved in the cause of death. CONCLUSION: Non-typical clinical symptoms present in the most cases caused by PTE, and these cases always show many high-risk factors. The relation between PTE and injury or medical behavior should be considered carefully in the forensic pathological practice.

[Analysis of 59 Anaphylactic Death Cases].

OBJECTIVE: To analyze the cases of anaphylactic death cases and explore the standards of judicial expertise of anaphylactic death for providing evidence for judicial expertise. METHODS: Fifty-nine cases death due to allergic reaction in Shanghai were collected. And details of medical history, clinical manifestation of anaphylactic reaction and postmortem examination findings were reviewed for all cases. RESULTS: In the 59 cases, there were 58 cases died from drug allergy, including 77.6% of them were antibiotics. The rates of treating in standard hospital and illegal clinic were 37.3% and 61.0%, respectively. The allergic symptoms were dyspnea and facial cyanosis. The time from contacting allergens to death ranged from 1 min to 3 d. The concentration of total serum IgE ranged from 50 to 576.92 IU/mL. The results of clinical manifestation and pathological anatomy had obviously changes. CONCLUSION: Based on the exclusion of all other cause of death and synthetically analysis of details of cases, medical history, clinical manifestation and anatomy, the conclusion of anaphylactic death can reached. The details of cases including clinical history, exposure to allergens, and clinical manifestation play an important role in diagnosis of anaphylactic death.

[Expression of Zonula Occludens-1 in Cerebral Cortex Following Traumatic Brain Injury].

OBJECTIVE: To observe the time-course expression of zonula occludens-1 (ZO-1) in cerebral cortex after traumatic brain injury (TBI). METHODS: The TBI model of mouse was established. The mice were divided in 1 h, 3 h, 6 h, 12 h, 24 h, 3 d, 7 d after TBI, sham and control groups. The permeability of the blood brain barrier was evaluated by measuring the extravasation of Evans blue (EB) dye. The expression of ZO-1 in cerebral cortex in the injured area was detected by Western blotting and immunohistochemistry. RESULTS: The extravasation of EB dye of injured cortex gradually increased from 1 h, peaked at 1-3 d and approximately decreased to normal at 7 d after TBI. Western blotting revealed that the expression of ZO-1 gradually decreased after 1 h, was at the lowest at 1-3 d, and then significantly increased after 7 d but was still lower than that of normal and sham groups. The result of immunohistochemistry showed that ZO-1 had strong expression in vessel of normal cortex, gradually decreased after TBI, and almost disappeared at 3 d after TBI and gradually recovered to normal level later. CONCLUSION: The expression of ZO-1 in the injured cortex after TBI initially decreases and then increases. The negative correlation between ZO-1 expression and EB extravasation after TBI could be used as a new indicator for wound age estimation.

Karoshi Related to Labor Intensity and Risk of Cardiovascular Events: A Case Report.

Karoshi remains one of the most troublesome issues in forensic identification. It is rather a social medicine than a clinical disease. Japanese scholars pioneered examining the relation between sud- den cardiac death (SCD) and chronic fatigue from long time and/or high-tension work. In the current case, a 55-year-old man, whose job was loading and carrying heavy cement bags, was found dead after 11 days of continuous hard work. His family members sued the cement factory for his death and claimed for compensation. The problem was the difficulty of identifying the causative relation without the precedent or the relevant regulations. However, the forensic problems were finally acknowledged after autopsy and calculation of labor intensity. The lawsuit was won as the first case pertaining to Karoshi in the Chinese court.

[Research Advances in Postmortem Chemistry].

Postmortem chemistry is becoming more and more essential in routine forensic pathology and has made considerable progress over the past years. Biochemical analyses of vitreous humor, blood, urine and cerebrospinal fluid may provide important information in determining the cause of death or in elucidating forensic issues. Postmortem chemistry may be essential for the determination of cause of death when morphological methods (diabetes mellitus, alcoholic ketoacidosis and electrolytic disorders) cannot detect the pathophysiological changes involved in the death process. It can also provide many information in other forensic situations, including myocardial ischemia, sepsis, inflammation, infection, anaphylaxis and hormonal disturbances. The most recent relevant research advances on glucose metabolism, liver function, cardiac function, renal function, sepsis, inflammation, infection, anaphylaxis and hormonal aspect are hereby reviewed.

[Application of MSCT in the identification and analysis of traffic accidents: 2 fatal cases].

OBJECTIVE: To explore the application value of multi-slice spiral computed tomography (MSCT) in traffic accidents through observing and analyzing the injury features of the accidents. METHODS: Two fatal cases caused by traffic accidents were fully examined using MSCT, 3D imaging reconstruction and angiography through cardiac puncture. The features of traffic injury mechanism were analyzed through combination of MSCT and postmortem external examination. RESULTS: In case 1, right cardiac rupture was found by MSCT and angiography through cardiac puncture. The cause of death was cardiac tamponade and right ventricular rupture due to the crush injury of chest in the traffic accident. In case 2, splenic rupture and intra-abdominal hemorrhage was found and caused by injury of left trunk by MSCT. The cause of death was hemorrhage and traumatic shock. CONCLUSION: MSCT could observe skeletal injury, soft tissue injury, and hematologic disorder well. The combination use of MSCT and angiography through cardiac puncture provided assistance to the diagnosis of cardiovascular system injury.

Characteristics of electrically injured skin from human hand tissue samples using Fourier transform infrared microspectroscopy.

This technical note describes a method for distinguishing normal skin tissue samples from those electrically injured by Fourier transform infrared microspectroscopy (FTIR MSP). Furthermore, the infrared spectral features of electrically injured cells and tissues were evaluated to identify molecular changes in epidermal cells. In the present study, 20 human hand tissue samples were evaluated macroscopically and histopathologically. The electrically injured skin samples were subdivided into 2 regions [normal cell regions (NCRs) and polarized cell regions (PCRs)] and 14 major spectral absorption bands were selected. The spectral results showed that the band absorbance at 1080, 1126, 1172, 1242, 1307, 1403, 1456, 1541, 2852, 2925, 2957, 3075, and 3300cm(-1) increased significantly both in the stratum and non-stratum corneum of the PCRs in electrically injured skin tissues samples. No significant difference was found between normal skin and the NCR of the electrically injured skin samples. The band absorbance ratios of A1172/A1126, A1456/A1403, and A2925/A2957 were significantly increased, whereas the A1652/A1541 ratio was decreased in the PCR of the stratum corneum and non-stratum corneum. Baseline changes from 4000 to near 1737cm(-1) were observed in the spectra of the electrically injured skin samples, which were interpreted in terms of the pathological process involved in electrical injury. FTIR-MSP presents a useful method to provide objective spectral markers for the assisted diagnosis of electrical marks.

[Research development and application of virtopsy].

Autopsy represents traditional and classical examination in forensic medicine. It was suggested that conventional autopsy, nowadays sometimes rejected or not tolerated by people for its damage to corpse. Virtopsy offers a non-invasive investigation approach and can also reflect fracture, soft-tissue injury, wound track, organ trauma objectively and accurately. Thus, virtopsy can provide visual and powerful evidence for forensic pathological practice. This article mainly synthesizes the latest literature at home and abroad and reviews application of virtopsy in forensic trauma identification, mechanical asphyxia, drowning, hypothermia and hyperpothermia, disease diagnosis and research of finite element method applicated in trauma investigation to illustrate this new direction of forensic research.

[Screening and identification of forensic molecular markers of injury using MALDI-TOF-MS imaging mass spectrometry].

There are many deficiencies in forensic traumatic molecular markers detected by the techniques of traditional immunohistology and molecular biology, because these markers are isolated and obscure of the mechanism of interaction. The imaging mass spectrometry (IMS) is more suitable for the forensic molecular markers using function of screening, analysis and graphical representation. In this paper, the techniques and the latest research in screening and identification of typical molecular markers by IMS based on matrix-assisted laser adsorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) are reviewed. And its application values in forensic injury are discussed.

[Analysis of biochemical markers in serum of guinea pigs after death caused by hypothermia].

OBJECTIVE: To explore the changes and rules of biochemical markers in serum of guinea pigs after death caused by hypothermia and to provide references for fatal hypothermia diagnosis by serum biochemical markers. METHODS: Twenty guinea pigs were randomly divided into experimental group and control group. The guinea pigs in the experimental group were kept at -30 °C until death, while the ones in control group were decapitated after same survival intervals at 25 °C. The serum was extracted from the whole blood of right ventricular immediately. Subsequently, a series of serum biochemical markers were analyzed by auto bio-chemical analyzer. RESULTS: The levels of glucose, uric acid, creatinine and urea nitrogen in the experimental group were significantly higher than those in control group, respectively (P<0.05). Compared with the control group, the levels of total protein and albumin were significantly lower in the experimental group (P<0.05). There were no significantly differences of the levels of other markers such as serum enzymes and ions observed between the two groups. CONCLUSION: There are characteristic changes of some specific serum biochemical markers in fatal hypothermia, which may be potentially useful for auxiliary diagnosis of fatal hypothermia.

3D finite element model of human knee injuries in the traffic accident.

OBJECTIVE: To explore the injury mechanism of the human knee in a traffic accident by establishing a 3D finite element (FE) model. METHODS: The FE model, composed of femur, tibia, fibula, patella, meniscus, knee ligaments and surrounding soft tissues, was reconstructed by CT scanning data from a male volunteer. Validation was performed by the lateral impact simulation, and the stress and strain results were obtained to be compared with those previously reported for injury prediction. RESULTS: The results derived from the FE model were found to be similar with those previously reported, most of the ligaments and meniscus wounded at 40 m/s collision, which was readily observed. CONCLUSION: The simulation results generated by FE model can be effectively used for the injury mechanism analysis of initial contact.