Expression of NF-κB in Schwann cells and its effect on motor neuron apoptosis in spinal cord following sciatic nerves injury in rats

Objective：To explore the expression of nuclear factor-kappa B （NF-kB） in Schwann cells （SCs） and its effect on motor neuron apoptosis in spinal cord following sciatic nerves injury in adult rats. Methods： Thirty-six adult Sprague-Dawley （SD） rats were divided randomly into normal control group （n=6）, and sciatic nerves crushing group （n= 30）, and the later was further equally randomized into 5 subgroups： 1, 3, 7, 14, and 21 d post-injury groups. The expression of NF-kB of normal and injured nerves were examined by immunohistochemistry staining, and the apoptosis of motor neurons in spinal cord of lumbar 4 to lumbar 6 （L4-L6） was investigated by terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling （TUNEL） assay. Both were qua.ntitated by image analysis. Results： In crushing group, except 21 d post-injury group, the expression of NF-kB was markedly higher than that in the normal control group （P〈0.05, P〈0. 01）. At 1 d after sciatic nerves crushing, the expression of NF-kB was obviously up-regulated, reached peak at 3 d, and recovered at 21 d. The same trend was observed in the time-course on motor neuron apoptosis after sciatic nerves injury. Correlation analyses revealed that motor neuron apoptosis was significantly and positively correlated with the expression of NF-kB following sciatic nerves injury （r= 0. 976 0, P〈0. 01）. Conclusion： After injury of sciatic nerves, the presence and up-regulation of NF-kB in SCs may be involved in motor neuron apoptosis in L4-L6 spinal cord.

Influence of neurotrophin-3 on Bcl-2 and Bax expressions in spinal cord injury of rats

Objective： To study the protective mechanisms of neurotrophin-3 （NT-3） on the spinal cord injury. Methods：Totally 105 SD rats were randomly divided into 3 groups： control group, experimental group and sham operation group. Rats from the former 2 groups were inflicted to animal model of acute spinal cord injury according to Allen＇s （WD） by situating a thin plastic tube in the subarachnoid space below the injury level for perfusion. Rats in experimental group received 20 ul NT-3 （200 ng） from the tube at 0, 4, 8, 12, 24 h and 3, 7 d after injury, and those in control group got an equal volume of normal saline at the same time. The animals in sham operation group only received opening vertebral plate and tube was put in subarachnoid space. The rats were sacrificed at 4, 8, 12, 24 h and 3, 7, 14 d post injury （n=5）. The expression levels of Bcl-2 and Bax proteins in spinal cord of rats were detected by immunohistochemistry assay. Results： The level of Bax protein in control group significantly increased as compared with those in sham operation group, and the peak reached at 8 h after spinal cord injury. The Bcl-2 proteins were always weakly positive. The Bax proteins in NT-3 group significantly decreased but the Bcl-2 proteins obviously increased as compared with those in control group. Conclusion： NT-3 can protect spinal cord from injury in vivo. One of the mechanisms is that NT-3 can inhibit abnormal expression of Pax protein, and increase the expression of Bcl-2 protein, then inhibit apoptosis after spinal cord injury.

Damage Assessment of Existing Transmission Structures Using ANFIS （Adaptive Neuro-Fuzzy Inference） Model

This paper introduces a new methodology for the damage assessment of existing-transmission structures using six layers, zero order Sugeno model. The model is a hybrid fuzzy-neural system that combines the power of neural networks and fuzzy systems. It is a learning expert system that finds the parameters of the fuzzy sets and fuzzy rules by exploiting approximation techniques from neural networks. The condition ratings of the structural components are determined based on visually observed deterioration-symptoms and the severity of those symptoms. A supervised learning process using training data and expert opinions is used to develop the expert system rules and determine the ratings of the structural components. For the learning from training data, the model uses a combination of least-square estimator and gradient descent method. A sequential least square algorithm is used to determine the weighting factors that minimized the errors. A test case is given to illustrate the power of the proposed fuzzy-neural system. It is concluded that the Sugeno model＇s ability to tune the parameters based on the training data makes it superior to the rules produced by an expert in the conventional fuzzy logic systems.

Meta-analysis of mNGF therapy for peripheral nerve injury： a systematic review

Objective： To assess the efficacy and safety of mouse nerve growth factor （mNGF） in patients with peripheral nerve injury. Methods： Such electronic database as Cochrane Library （Issue 1,2011）, Medline （1950-2011）, Embase （1980- 2011）, National Knowledge Infrastructure （ 1979 -2011 ） were searched and meanwhile relevant journals such as Chinese Journal of Orthopaedics, Chinese Journal of Microsurgery, Chinese Journal of Neurosurgery, ere were searched as well to collect all randomized controlled trials and quasi-randomi- zed controlled trials of mNGF on patients with peripheral nerve injury. The quality of included studies was assessed according to the criteria recommended by the Cochrane Handbook for Systematic Reviews of Interventions and the data were extracted by two reviewers independently. Meta- analysis was conducted by RevMan 5.1 software. Results： Forty-one studies involving 3 304 patients with peripheral nerve injury were included. The results of meta-analysis showed that： （1） the total effective rate ofperipheral nerve injury treatment in mNGF group was obviously higher than that in control group （OR=6.36, 95% C1 4.96-8.15, P〈0.01）; （2） the scores of activities of daily living （ADL） in mNGF group was significantly higher than that in control group （weighted mean difference=1.97, 95% CI 1.33- 2.61, P〈 0.0 l）; （3） the incidence of adverse reaction in mNGF group was higher than that in control group, （OR= 1.66, 95% CI 1.61-2.38, P=0.006）, but the adverse effects were mild, which could be relieved without specific treatment or just given symptomatic treatment, and disappeared at the end of treatment. Conclusions： The mNGF therapy is effective for peripheral nerve injury. It can obviously improve patient＇s ADL. Though the incidence of adverse reaction in mNGF treatment group is higher than that in control group, this does not influence the treatment outcomes.

Closed reduction and percutaneous pinning of displaced supracondylar fractures of humerus in children with delayed presentation

Objective： Supracondylar fractures of the humerus account for 60% of all the fractures around the pediatric elbow and even in developed countries 18% of patients undergo surgery 48 hours or longer following presentation in the hospital. Management guidelines are not clear yet for these patients who present late. The aim of this prospective study was to evaluate the clinical, radiological and functional outcome following closed reduction and percutaneous pinning of widely displaced supracondylar fractures of the humerus presenting 12 hours or more after injury.Methods： We reviewed the functional and radiological results of closed reduction and percutaneous pinning using crossed K-wires in 40 patients with displaced extension type supracondylar fracture of the humerus （Gartland type Ⅲ） with a delay of more than 12 hours in presentation. The average age of patients was 4.5 years and the mean delay in presentation was 17.55 hours.Results： Closed reduction and percutaneous pinning was successful in 90% of patients. The mean follow up period was 15 months. The Baumann＇s angle was restored within 4 degrees of the unaffected side in all patients. Use of a small medial incision in patients with severe swelling helped us avoid ulnar nerve injury. Using Flynn＇s criteria,38 patients （95%） had an excellent result. Two patients had mild myositis and both had a poor result. None of the patients developed cubitus varus.Conclusion： Closed reduction and crossed pinning of displaced supracondylar fractures of humerus in children is a safe and effective method even with delayed presentation.

Repeat cranial tomography in patients with mild head injury and stable neurological examination - a perspective from a developing country

Objective： To determine the frequency of altered findings on repeat cranial tomography （CT） in patients with mild head injury along with stable neurological examination at tertiary care hospital.Methods： Cross-sectional study was done in the Department of Radiology, Liaquat National Hospital, Karachi from January 2008 to September 2010. All patients with mild head injury in terms of Glasgow Coma Scale （GCS） who underwent repeat scan without clinical or neurological deterioration in the emergency department of a tertiary care centre were included. The collected data were accordingly entered and analyzed by the principal investigator using Statistical Package for Social Sciences （SPSS） version 16.0.Results： In all 275 patients, only 17 （6%） of the patients were found worseing on repeat CT, 120 （43.63%）scans improved, 138 （50.18%） unchanged and 17 （6.18%）worsened. None of these patients showed signs of clinical deterioration.Conclusion： Our results suggest that for patients with mild head injury and stable neurological examination, only 6% of them show deterioration on repeat CT, especially when patients＇ GCS is below 13.