[Influence of visual attention in visual evoked potential examination].

OBJECTIVE: To explore the influence of visual attention in visual evoked potential (VEP) examination. METHODS: The pattern visual evoked potential (PVEP) and flash visual evoked potential (FVEP) were used to examine 110 normal subjects whose visual acuity or corrected visual acuity is in the range of 4.8-5.2, and age between 20 to 30 years old. In PVEP inspection, subjects were asked to watch with three ways, to stare at the central screen (at the same time count silently the number of alternating of black and white squares to improve the subjects' attention), to stare at the central screen at the same time thinking other things, to look sideways (the left eye stared at the left bottom corner of the screen or the right eye stared at the right one). In FVEP inspection, subjects were checked with eyes open and closed respectively. The latency and amplitude of P100 wave were recorded. The data were statistically analyzed by SPSS 13.0 software. RESULTS In PVEP inspection, the latency and amplitude of P100 wave were statistically different among three watching ways. In FVEP inspection, latency and amplitude of P100 wave were statistically different between eyes open and closed group. CONCLUSION: Although the visual evoked potential test is an objective electrophysiological visual function test, it is susceptible to the influence of various subjective factors such as visual attention. It should arise the attention of forensic experts.

[Concentration changes of potassium and hypoxanthine in vitreous humor of swine and its application to postmortem interval estimation].

OBJECTIVE: To investigate the relationship between postmortem interval (PMI) and concentration changes of components in swine vitreous humor. METHODS: Ninety-six porcine eyes from swine dying from acute massive hemorrhage, being randomly divided into 24 groups, were stored in dark situation, at temperature of (15 +/- 2) degrees C and humidity of (50 +/- 5)% for 2-96 hours separately. The vitreous humor was collected. Concentrations of K+, Na+, Cl- and hypoxanthine (Hx) were analyzed by automatic biochemical analyzer and ultra performance liquid chromatograph (UPLC). The data were statistically analyzed by SPSS software. RESULTS: Linear regression analysis showed that concentrations of vitreous K+ and Hx were positively correlated with PMI(R2=0.767 and R2 = 0.793, respectively). Binary linear regression showed a higher correlation for K+ and Hx with PMI estimation (R2 = 0.866). PMI was not significantly correlated with vitreous Na+ and Cl- concentrations. CONCLUSION: Vitreous K+ and Hx concentrations can be used as the objective markers for PMI estimation. The binary linear regression functions of vitreous K+ and Hx concentrations with PMI are more accurate for estimating the PMI.

[DNA degradation of porcine retinal cells for estimation of postmortem interval].

OBJECTIVE: To investigate DNA degradation of porcine retinal cells by single cell gel electrophoresis (SCGE) for estimation of postmortem interval (PMI). METHODS: Degradation of retinal cells was observed by SCGE at 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24h after death respectively, under the environmental conditions of being kept in dark place as well as a controlled temperature of (15 +/- 2) degrees C and humidity of (50 +/- 5)%. The comet pictures were captured by fluorescence microscope and analyzed by single cell gel electrophoresis (IMI 1.0). RESULTS: From 2h to 24h postmortem, the degree of degradation of retinal DNA increased with the prolongation of PMI. The postmortem regression functions of head DNA%, L(T)/L(H), I(T)/I(H) were y = 92.227-5.188 x + 0.019 x2 + 0.001 x3 (R2 = 0.971), y = 0.035e(0.191x) (R2 = 0.947), y = 0.099e(0.264x) (R2 = 0.955), respectively. CONCLUSION: The examination of retinal cell DNA degradation by SCGE is useful for estimating PMI.

[Morphology changes of ubiquitin-proteasome system in traumatic epilepsy].

OBJECTIVE: To investigate the value of ubiquitin(Ub) and ubiquitin-activating enzymel(UbE1) for the appraisement of post traumatic epilepsy (PTE). METHODS: Fifteen specimens from human epileptic temporal cortex originating from PTE were collected as the PTE group. Fifteen specimens from non-PTE were collected as the non-PTE group. Meanwhile, 15 normal cerebral cortex specimens from people dead from acute traffic accident were collected as the control groups. Observe morphology changes of each group with HE, then with immunohistochemistry of Ub and UbE1. RESULTS: Compared to the control group, morphology changes of neuron quantity reduction, neuron denaturation and so on were observed both in the PTE group and the non-PTE group under HE, especially in the PTE group. Ub and UbE1 mainly expressed in the nucleus and cytoplasm of the neurons in epilepsy spot without extracellular expression. The expression of Ub and UbE1 is PTE group > non-PTE group > control group (P < 0.05). CONCLUSIONS: The neuron denaturation are one of the main pathology changes of epilepsy, and it is more obvious in the PTE group. Immunohistochemistry of Ub and UbE1 may be more helpful to distinguish PTE and non-PTE than HE staining.

[The suppression of c-fos in neuron apoptosis induced by heroin].

OBJECTIVE: To explore the changes of c-fos in apoptosis of cerebellar granular neuron of neonatal SD rats induced by heroin and the mechanisms of neuronal injury caused by heroin. METHODS: Primary cerebellar granular neuron were cultured in vitro, the model of apoptosis induced by heroin was established. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were adopted to investigate the changes of c-fos in cell models. RESULTS: Ten microg/mL of heroin was the optimal dose to induce the apoptosis of cerebellar granular neuron at 48 h. Both Western blotting and RT-PCR showed down regulation of c-fos expression. CONCLUSION: Heroin could induce apoptosis of cerebellar granular neuron and down regulation of c-fos, which may be one of the apoptosis mechanisms.

[The relationship between PMI and concentration of potassium ion and sodium ion in swine aqueous humor after death].

OBJECTIVE: To explored the relationship between the concentration of potassium ion as well as sodium ion in the aqueous humor and post-mortem interval (PMI). METHODS: The concentrations of potassium ion and sodium ion in the aqueous humor of swine within 48 h after death at 4 degrees C and 28 degrees C were detected using Z-500 atomic absorption spectrophotometer. RESULTS: The concentrations of potassium ion and sodium ion in aqueous humor of isolated swine eyeballs within 48 h after death when the environmental temperature was 4 degrees C were significantly related to PMI. The relationship between PMI and the concentration of potassium ion was PMI = -0.178[K+]2 + 49.978 (R2 = 0.995). The relationship between PMI and the rate of sodium ion and potassium ion was PMI = 120.987/[Na+/K+]-28.834 (R2 = 0.905). CONCLUSION: The concentration of potassium in aqueous humor of isolated swine eyeballs may be one of the reference indicators to estimate PMI of the corpses at lower temperatures.

[The quantitative analysis of Ub and UbE1 in focus of traumatic epilepsy].

OBJECTIVE: To study the expression of ubiquitin proteasome system (UPS) in the traumatic epilepsy pathogenesis and its value in traumatic epilepsy by quantitative analysis. METHODS: Fifteen specimens from human epileptic temporal cortex from PTE were collected as the PTE group. Fifteen specimens from non-PTE were collected as the non-PTE group. Fifteen normal cerebral cortex specimens died from acute traffic accident were collected as the control group. The expression of mRNA and protein of Ub and UbE1 were detected by RT-PCR and Western blot. Statistical analysis was used to compare the data between three groups. RESULTS: The expression of mRNA and protein of Ub and UbE1 were the following order: PTE group(high), non-PTE group(middle) and control group(low). CONCLUSION: The study confirms that UPS is up-regulated in the epilepsy's focus, especially in traumatic epilepsy. The activation of UPS may be an important pathological change in neurons in pathogenesis of traumatic epilepsy.

[The value of TNFalpha testing in evaluation of death due to drug anaphylactic shock].

OBJECTIVE: To analyze the changes of the serum TNFalpha level in cadavers of drug anaphylactic shock(DAS) and to explore the significance of the TNFalpha testing in evaluation of death caused by DAS. METHODS: The level of serum TNFalpha from cardiac blood was determined by double antibody-sandwich ELISA method. RESULTS: The level of TNFalpha in the experimental group was (131.6+/-9.4) pg/mL, while the level in the infectious diseases control group and the normal control group were (87.3+/-6.4) pg/mL and (17.2+/-4.5) pg/mL, respectively. There was statistically significant difference among the groups (P<0.05). CONCLUSION: The serum TNFalpha level may be used as one of the indexes for evaluation of death caused by highly suspected drug anaphylactic shock.

[Recent progress in research on positional asphyxia of restraint].

Positional asphyxia of restraint means that when an individual was limited in an abnormal body position, asphyxia would take place owing to the disorder of spontaneous respiratory function, and finally it lead to die. So, it belongs to a special type of the mechanical asphyxia. From the cases reported, we could found that it would take place in several conditions. Because the cases were not caused enough recognition, the study has been researched carefully only in recent years. Following the more cases reported, many experts of forensic medicine had investigated it on the mechanism of death and the standard of identification, but they could not reach to agreements. So, they have changed the directions of the researches, began to value the factors of risk and research how to avoid it. In the following text, the mechanism of death, factors of risk, preventive methods, standard of identification and prospecting of positional asphyxia of restraint were reviewed.

[Analysis on the injury by lock-against-theft].

Nowdays, it is common seen that criminals tend to use the lock-against-theft for motorcycle to harm others as a tool. In order to find out the chief characters of this kind of injury, 28 cases in which victims were hurt by lock-against-theft for motorcycle were analyzed. In each case, the victims carefully questioned to confirm the damage procedure. Furthermore, the wound configuration was observed and the forming mechanism was deduced to provide morphological evidences for the judgement in this kind of case.

[Cellular mechanism of heart injury in the early stage of crush injury in rats].

OBJECTIVE: To study cellular mechanism of cardiomyocytes injury in the early stage of crush injury by observing some effects of crush injury rat sera on cultured neonatal rat cardiomyocytes. METHODS: One to three days old neonatal rat cardiomyocytes were cultured in vitro and some effects of crush injury rat sera on beating rate, cell surface area, total protein content, 3H-Leu incorporation, intracellular calcium concentration ([Ca2+]i) and Fos protein expression were observed in cultured rat cardiomyocytes. RESULTS: Compared with normal rat serum group, crush injury rat sera decreased beating rate(beats/min) of cardiomyocytes from 88.3 to 26.4, cell surface area, total protein content, 3H-Leu incorporation, [Ca2+]i (nmol/L) and PI of Fos protein expression were increased. CONCLUSION: Crush injury rat sera suppress cell beating, increase intracellular calcium, induce Fos protein synthesis and cause cell hypertrophy, which may cause cardiac injury in the early stage of rush injury.

[Immunohistochemical study of thrombomodulin expression in multiple organs dysfunction syndrome].

OBJECTIVE: To study the expression of thrombomodulin (TM) and its significance in the pathogenesis of multiple organs dysfunction syndrome (MODS). METHODS: TM expression was determined by immunohistochemical staining in 20 autopsy cases with MODS group and 12 autopsy cases without MODS (control group). RESULTS: Significant differences in positive expression of TM in heart, lungs and kidneys were found between the control group and MODS group (all P<0.01). CONCLUSION: The increase of TM secretion results in homeostatic disturbance, which might be one of the important mechanisms of MODS.

[Immunohistochemical study of fibronectin in multiple organ dysfunction syndrome in elderly rats].

OBJECTIVE: To study the characteristic of endothelial injuries and the mechanisms of coagulation disorder in multiple organ dysfunction syndrome in elderly rats by observing the distribution and the intensity of fibronectin (FN) expression in important viscerae including the heart, brain, lung, kidney, liver. METHODS: Fifty Wistar rats (one half of them were 3 months old, another half 20 months old) were anaesthetized and cecal ligation puncture (CLP) was done. They were defined as MODS group and MODSE group. Forty Wistar rats (one half of them 3 months old, another half 20 months old) were anaesthetized and laparotomy was done as sham operation group (SOG) and sham operation group in elderly (SOGE). The heart, brain, lung, liver and kidney were harvested and were examined histologically at 6, 12, 24, 48 or 72 hours after operation. They were also stained immunohistochemically by using anti-FN as the first antibody. RESULTS: The expression of FN on the surfaces of vascular endothelial cells in hearts, brains, lungs, livers, kidneys was weakly positive or positive in MODSE, MODS or SOGE group, but it was positive or strongly positive in SOG group. The differences were significant (P<0.05). CONCLUSION: The injury of endothelial cells and the disorders of coagulation system are observed in MODSE, MODS, SOGE groups, especially in MODSE.

[Expression of the glycoprotein in atrioventricular cell membrane of acute myocardial infarction in human].

OBJECTIVE: To study the expression of the glycoprotein in atrioventricular cell membrane of the acute myocardial infarction. METHODS: The glycoprotein changes occurred at the atrioventricular cell membrane of the acute myocardial infarction of 8 cases were observed by using immunohistochemical methods. RESULTS: Positive staining of PNA could be observed in atrioventricular cell membrane. CONCLUSION: This experiment proved that atrioventricular cell membrane expressed D-galactose as same as myocardial cell membrane in the acute myocardial infarction.