Hui Zhao

Third Military Medical University, Ch’ung-ch’ing-shih, Chongqing Shi, China

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Publications (4)0 Total impact

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    ABSTRACT: Objective: To investigate the expression of Caspase-3 and Hsp70 in rabbits after severe traumatic brain injury (TBI) and to explore the feasibility of its application in estimation of injury time in forensic medicine. Methods: A rabbit model of heavy TBI was developed by high velocity impact on the parietal bone with an iron stick. Totally 8 healthy adult New Zealand white rabbits were randomly divided into control group (n equal to 2) and injury group (n equal to 6). Four hours after injury, tissue specimens from the parietal lobe, temporal lobe, occipital lobe, cerebellum and brainstem were harvested to detect the expression of Hsp70 and Caspase-3 by immunohistochemistry. Besides, the gray values of cells positive for Hsp70 and Caspase-3 were analyzed with an image analyzer. Results: Immunohistochemistry staining demonstrated a low level of Caspase-3 and Hsp70 expression in normal control group. While in injury group, both the Caspase-3 and Hsp70 expression was significantly elevated (P less than 0.05). Positive cells gathered around the lesion focus. Occipital lobe and cerebellum had fewer positive cells while temporal and brainstem had the fewest. Conclusion: The expression of Caspase-3 and Hsp70 at an early stage following severe TBI is characteristic and can be applied to estimate the time of injury.
    Chinese Journal of Traumatology (English Edition) 12/2012; 15(6):338-41.
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    ABSTRACT: Objective: To introduce a new animal model of graded mechanical primary brainstem injury (BSI). Methods: Altogether 45 rabbits were subjected to BSI by type II biological impact machine designed by the Third Military Medical University. The animals were divided into 4 experimental groups (n equal to 10) and 1 control group (n equal to 5) according to different magnitudes of impact pressure imposed on the occipital nodule: Group 1, 500-520 kPa; Group 2, 520-540 kPa; Group 3, 540-560 kPa; Group 4, 560-580 kPa and Group 5, 0 kPa with 20 kPa increase in each grade. The impact depth was a constant 0.5 cm. After injury, the clinical symptoms and signs as well as pathological changes were observed. Results: Rabbits in Group 1 revealed mild physiological reaction of BSI. They had localized cerebral contusion with punctate hemorrhage and subarachnoid hemorrhage (SAH) was limited to the peripheral tissues at the impact area. In Group 2, obvious physiological reaction was observed. Local pathological lesions reached the superficial layer of brainstem tissues; focal hemorrhage and girdle-shaped SAH in basilar pon were observed under microscope. In Group 3, BSI was more severe with a long respiratory depression. Pathological lesions reached the inner portion of brainstem with massive hemorrhage and the whole brainstem was wrapped by subarachnoid hematoma. In Group 4, most rabbits died due to severe BSI. Pathological lesions deepened to the central brainstem with wide pathological change, rapture of the medulla oblongata central canal. Group 5 was the control group, with normal brainstem structure and no lesion observed.Conclusion: This model successfully simulates different levels of brainstem mechanical injury and clearly shows the subsequent pathological changes following injury. It takes two external parameters (impact pressure and depth) and has a similar injury mechanism to clinical accelerating BSI. Moreover it is reproducible and stable, thus being be- neficial for exploring pathophysiological mechanism, diagnosis and forensic identification of various degrees of BSI.
    Chinese Journal of Traumatology (English Edition) 12/2012; 15(6):346-51.
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    ABSTRACT: Objective: To analyze the injuries of motorcyclists involved in fatal motorcycle frontal crashes. Methods: A survey group involving multi-discipline experts was built to randomly collect data on fatal motorcycle frontal collision accidents that occurred in Chongqing during 2006-2010. The sampled information included medical or autopsy reports, blood alcohol concentration (BAC) level, helmet use, accident witness, field sketch as well as field photos. The motorcyclist injuries were scored according to the Abbreviated Injury Scale (AIS) 2005. The involved riders with a BAC level larger than or equal to 20 mg/ml were attributed to alcohol use. Data were processed statistically with nonparametric test via software SPSS 11.0. Results: A total of 86 fatal motorcycle frontal crashes were sampled and further analyzed. The age of motorcyclists enrolled in this investigation showed nominal distribution and the middle-aged (30-39 years) occupied the highest percentage of fatalities. There were only 14 motorcyclists (16.3%) wearing helmets at the moment of collision. And 12.8% of these motorcyclist crashes were attributable to alcohol use. Impact injury was the main fatal cause, accounting for 72% of motorcyclist deaths, followed by tumbling injury (26%) and run-over (2%). Respectively 84%, 22% and 19% of motorcyclists who sustained head, chest and abdominal trauma died. Extremity injury was the most frequently observed injury type. Conclusions: This investigation is helpful to build accident prevention programs and develop protection devices which may effectively mitigate injuries and prevent deaths following motorcycle frontal collision accidents. Further investigations on motorcycle collision accidents are still needed.
    Chinese Journal of Traumatology (English Edition) 06/2012; 15(3):170-4.
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    ABSTRACT: Objective: To establish an animal model to replicate the blunt impact brain injury in forensic medicine.Methods: Twenty-four New Zealand white rabbits were randomly divided into control group (n equal to 4), minor injury group (n equal to 10) and severe injury group (n equal to 10). Based on the BIM-II Horizontal Bio-impact Machine, self-designed iron bar was used to produce blunt brain injury. Two rabbits from each injury group were randomly selected to monitor the change of intracranial pressure (ICP) during the impacting process by pressure microsensors. Six hours after injury, all the rabbits were dissected to observe the injury morphology and underwent routine pathological examination. Results: Varying degrees of nervous system positive signs were observed in all the injured rabbits. Within 6 hours, the mortality rate was 1/10 in the minor injury group and 6/10 in the severe injury group. Morphological changes consisted of different levels of scalp hematoma, skull fracture, epidural hematoma, subdural hematoma, subarachnoid hemo- rrhage and brain injury. At the moment of hitting, the ICP was greater in severe injury group than in mild injury group; and within the same group, the impact side showed positive pressure while the opposite side showed negative pressure. Conclusions: Under the rigidly-controlled experimental condition, this animal model has a good reproducibility and stable results. Meanwhile, it is able to simulate the morphology of iron strike-induced injury, thus can be used to study the mechanism of blunt head injury in forensic medicine.
    Chinese Journal of Traumatology (English Edition) 04/2012; 15(2):100-4.