BACKGROUND: What kind of traumatic changes could be observed in remote lumbar spinal cord after high-speed steel ball induced sciatic nerve injury?OBJECTIVE: To study the ultra structural changes of lumbar spinal cord motor neurons after the sciatic nerve injury due to high-speed steel ball.DESIGN: Retrospective randomized controlled study with experimental animals as subjects.SETTING: The field operation research institute of a military medical university college.MATERIALS: This study was carried out at the Ballistic Laboratory of Research Institute for Surgery from May 2001 to December 2002. Sixty-five SPF flap-eared rabbits of either gender weighing from 2.5 to 3.0 kg were provided by the Experimental Animal Center of Daping Hospital Affiliated to the Third Military Medical Univeristy of Chinese PLA. All the rabbits were divided randomly into normal control group( n = 5), firearms injury group (n = 30) and cutting injury group( n = 30) . The two latter groups were subdivided into one-day, three-day, one-week, two-week, 4-week and twelve-week groups with 5 rabbits in each group.METHODS: The rabbits in the firearms injury group were injured at the midpoint of lateral posterior body surface projection of the right sciatic nerve with 0. 38 g steel ball containing 0.65 g detonators. The right sciatic nerve was cut at the same injury level in the cutting injury group.MAIN OUTCOME MEASURES: The following pathologic changes of the lumbar spinal cord were observed with optical and electronic microscope at posttraumatic day 1, day 3 and week 1, week 2, week 4 and week 12 respectively.RESULTS: Micro-hemorrhage, neuron swelling and vacuoles were observed in the firearms injury group and the number of motor neurons decreased significantly, but these changes were unobservable in the cutting injury group.CONCLUSION: Compared with the cutting group, the injury to the spinal cord was severer in the firearms group and the survival neurons were less.

Objective To explore the possibility for preventing the underwater blast injuries. Methods Fifty rabbits were divided into two groups: protection and control groups. The animals were placed at the rang of 5.0m to 17.5m far from the explosion point. 0.2kg of TNT Explosives was placed 3 meters under water. Physical parameters of blast wave were measured using pressure transducers. At 6 hours after injury, the mortality rate and morphological alternations were observed. Results The safe devices were shown to be effective against underwater blast injuries. Most of the animals had no or mild pulmonary and intestinal injuries. The whole injury severity was reduced by 2 to 3 degrees with our own made device. Conclusion Our safe device could be used to protect against underwater blast injueirs.

AIM: To study antiasthmatic effect of citral from aqueous extract of fruit of cubeb litsea tree and its mechanism.METHODS: By inducing asthma with Ach-histamine method in guinea pig,cough with ammonia in mice and the output quantity of phenol red from the trachea in mice,the antiasthmatic was observed,preventing cough and eliminating phlegm effect of citral. By measuring the tension of guinea-pig isolated tracheal rings,the both influence of citral was observed on isolated guinea pig tracheal rings and inhibition's effects of citral on contraction induced by Ach.RESULTS: Citral prolonged apparently the incubation period of asthma due to Ach-histamine solution in guinea pig and the coughing incubation period,reduced coughing frequency induced by ammonia in mice,increased excretion of phenol red from the respiratory tract in mice,inhibited the constrictions induced by Ach,and shifted the dose-effect curves of Ach to the right.CONCLUSION: Citral has functions of expelling phlegm,relieving cough and resisting asthma,satisfactory bronchi spasmolysis.

Objective To analyze and discuss the possible reasons of the bone resorption beneath the prostheses after chin augmentation.Methods Twelve patients were admitted to our department for further correction after chin augmentation with materials.The bone resorption was observed through the clinical research and X-ray examination.Results All the patients were underwent the removal of the materials,genioplasty was performed in 8 patients,and two patients were treated by chin augmentation with polyethylene.All the patients were satisfied with their facial contouring.Mild bone resorption was found in seven patients (depth of bone resorption ≤2 mm),in which five patients were used with silicone materials,two patients were performed with expanded polytetrafluoroethylene implants.Moderate bone resorption was seen in three cases.All of them were used with silicone implants (2 mm ＜ depth of bone resorption ≤4 mm).Severe bone resorption happened in two patients (depth of bone resorption ＞4 mm).One was used with silicone implant,and the other one was carried out with expanded polytetrafluoroethylene implant.Conclusions The imbalance among mentalis muscle,materials and underlying bone might be one of the key reasons.Thus for mild and moderate microgenia cases,chin augmentation with material is suitable,while long-term fellow-up study is necessary.But for the cases of severe mirogenia or microgenia and micrognathia with dentofacial deformity or mentalis muscle hyperactivity,genioplasty might be performed as well to correct their deformities.

Objective to research the mechanical style(compressive or tensile force)of the key site of brain tissue in brain deceleration impact.Method a transparent physical brain model with air bubbles was built and loaded on an upright brain decaler ation impacting expedmentel platform.Then,the moveable platform was made a free fall from a height of 400mm and impacted on the fixed platform,and the whole deceleration impacting process was recorded by a high-speed video camera.Using the serial pictures analyzing Software,the length change of the long ads(vertical to the impacting direction)and the short axis(in the impacting di-rection)of the air bubbles were analyzed and calculated.Result the length change of the long axis of air bub-ble with in site coup was smallerthan the absolute value of that of the short axis;while with the air bubble in the contrecoup site,the length change of the long axis was bigger than the absolute value of the short axis.Conclusions the results showed that the air bubble in the coup site mainly suffered from the tensile force vertical to the impacting direction and the air bubble in the contrecoup site mainly suffered from the compres-sive force in the impacting direction.Since the propeny of tensile resistance of the brain tissue is inferior to the property of compressive resistance of the brain tissue, the injury is often easier to occur in the contrecoup site than in coup site. The results were of significance to the research of biomechanical mechanism, diagnosis and prevention of the brain deceleration impacting injury.

Objective To study characters of pathology associated with functional alteration of primary brainstem injury (PBI) at different injury severities in rabbits .Methods Animal model of graded PBI was produced using rabbits .Animals were di‐vided into five groups ,group Ⅰ to Ⅳ with an increase of impact power ,10 cases in each group ,and the control group with 5 cases . The pathology characters of PBI were investigated combining dissection observation with unaided eye ,tissue HE histochemical stai‐ning and electron microscope .Results Slight brainstem injury were observed in group Ⅰ ,and pathological results showed regional subarachnoid hemorrhage (SAH) ,stripping of regional cerebral pia mater ,a few petechial hemorrhage in surface ,nerve cell edema , normal medulla sheath and axon roughly .The brainstem injuries were apparent in group Ⅱ ,and the pathological changes indicated SAH in sheet ,petechial and sheeted hemorrhage in surface ,and slight swelling and vacuoles in nerve cells .The brainstem injuries were observed obviously in group Ⅲ ,exhibiting thick SAH ,petechial and sheeted hemorrhage in surface and inside ,degeneration of nerve cells ,abruption of axon ,and atrophy of axoplasm .Eight of ten animals died of respiratory depression induced by brainstem in‐jury in group Ⅳ ,presenting thick hemorrhage in subarachnoid surrounding brainstem ,the whole brainstem injured ,microscopically with multiple small hemorrhage ,nerve cells only residual nuclei ,myelin lamellar severe stratification and fracture ,and axonal tran‐section ,disintegration .No abnormal pathological changes were shown in control group .Conclusion The impacts to brainstem with higher powers lead to more manifest functional and more severe pathological changes ,with an alternation of injury location from surface to deep .

Objective To explore the risk factors and prognosis of hospitalized patients with bloodstream infection due to carbapenem-resistant Acinetobacter baumannii (CRAB).Methods 163 patients with CRAB bloodstream in-fection from 2010 to 2013 were conducted retrospective case-control study,68 patients with bloodstream infection due to carbapenem-susceptible Acinetobacter baumannii (CSAB)during the same period were as control group. Results The independent risk factors for CRAB bloodstream infection were stay in intensive care unit(ICU)(OR, 1 .27[95%CI ,5.55-22.89])and emergency department(OR,3.57 [95%CI ,1 .67 -7.62])before infection.Pa-tients with CRAB bloodstream infection had lower 28-day survival rate than those with CSAB bloodstream infection (66.17% vs 96.95%,χ2 =15.71 ,P <0.001 ).The independent risk factors for influencing prognosis of Acineto-bacter baumannii bloodstream infection were infection of CRAB (HR 95% CI ,3.01 -67.28),blood disease(HR 95%CI ,3.77-25.97),cardiac insufficiency(HR 95%CI ,2.10-20.41),stay in ICU(HR 95%CI ,1 .01 -5.28), and age(HR 95%CI ,1 .01 -1 .04).Conclusion The independent risk factors for CRAB bloodstream infection are stay in ICU and emergency department before infection,CRAB bloodstream infection is risk factor for influencing prognosis of patients.

Purpose: Set up a new technique to reproduce the cavitation effect in the process of brain deceleration impact Methods: A transparent physical brain model with tiny air bubbles was built and loaded on an upright brain deceleration impacting moveable platform. Then, in the high strength lighting circumstance, the moveable platform was made to free fall from a height of 40cm and impacted on a fixed platform, and the whole deceleration impacting process was recorded by a high-speed video camera. Using the serial pictures analysing software, the volume and mean pressure change of the air bubbles were calculated and the cavitation effect of the brain tissue during the impact was studied. Results: The volume of the air bubble in the contrecoup site increased obviously in the impacting process, the volume of the air bubble in the coup site decreased in the impacting process and the volume change of the air bubble in the middle site was not evident enough in the impacting process. Conclusion: The results proved the negative pressure and the cavitation phenomenon in the contrecoup site. The experiments explicitly and directly showed the cavitation effect in the contrecoup site during the decelerating impact It was helpful to better understand the distribution characters of the dynamic stress of the brain tissue in the brain decelerating impact in a certain extent, and it could also provide some methods and experimental foundation to clarify the mechanical mechanism of the brain contrecoup injury which was often taken place in traffic accidental injury. Besides, the methods were of significance to research the biomechanism, diagnosis and prevention of the brain deceleration impacting injury.

BACKGROUND: Magnetic resonance imaging(MRI)is considered safe for diagnosis of meniscus injury,having accuracy as high as 80% to 100%.However,it is found that there are some false positive and false negative in the clinic.OBJECTIVE: Through assessment of menisci injuries of the knee using magnetic resonance imaging and arthroscopy,to investigate MRI manifestation in different types of meniscal injuries.METHODS: A study from January 2003 to December 2008 was performed in 212 patients with knee injury undergoing preoperative MRI.Radiograph was read by physicians who had a senior professional title from radiology and orthopaedics departments,and meniscus damage and damage morphology were predicted.Arthroscopy was conducted by chief physician.Meniscus damage during surgery was considered as gold standards.The accuracy of them was compared.The statistics of accuracy of MRI diagnosis was gathered.RESULTS AND CONCLUSION: Totally 212 patients and 230 knees were included,and a total of 215 knees of meniscus injury were described by MRI diagnosis and 213 knees of meniscus injury were proven by arthroscopy.The sensitivity,specificity and accuracy of MRI diagnosis of meniscus injury respectively were 93.5%,64.7%,93.0%.It is found that the sensitivity of MRI diagnosis of bucket-handle damage is high.MRI is easy to miss diagnosis in a light meniscus posterior horn tear,and resuts are more false positive in lateral meniscus injury.It needs arthroscope operation or further surgery in some condition such as gradeⅢ type injury,meniscus displacement after injury and articular capsule separation,which indicates instable meniscus.

Objective To investigate the expression and significance of Bmi-1 in pancreatic cancer.Methods The expression of Bmi-1 mRNA was detected in pancreatic cancer and matched adjacent normal tissues by using real-time PCR in 22 cases of human pancreatic carcinoma.Bmi-1 and p16 protein were determined in 61 cases of human pancreatic carcinoma with immunohistochemistry and their relationship with clinicopathologic parameters was analyzed.Results The expression of Bmi-1 mRNA was 0.314 ±0.040 in cancerous tissues, and 0.143 ±0.056 in adjacent normal tissues, and the difference was statistically significant (P ＜0.01 ).36 cases (59.0%) of PC were detected with positive expression of Bmi-1 protein, and 34 cases (55.7%) with no expression of p16 protein.The expression of Bmi-1 was significantly correlated with lymph node metastasis ( P = 0.020 ) and tumor differentiation ( P = 0.018 ); the expression of Bmi-1 was negatively correlated with the expression of p16 ( P = 0.033 ).Conclusions Expression of Bmi-1 was increased in pancreatic cancer, which may be involved in the malignant behavior of pancreatic cancer by inhibiting p16 expression.