pSVPoMcat modifying Schwann cell to protect injured spinal neurons in rats.

OBJECTIVE: To investigate the protective effect of pSVPoMcat (myelin basic protein microgene) modifying Schwann cell on injured spinal neurons. METHODS: A model of rat spinal cord injured by hemisection was used. One hundred and twenty healthy SD rats of both sexes weighing 250-300 g were divided into three groups: Group A (n=40, treated with implantation of pSVPoMcat modifying Schwann cell), Group B (n= 40, treated with implantation of Schwann cell only) and Group C (n=400, treated with sham operation as the control). One week after operation the rat functional recovery was observed dynamically by using combined behavioral score (CBS) and cortical somatasensory evoked potentials, the spinal cord sections were stained by Nissl, acid phosphatase enzyme histochemistry and cell apoptosis was examined by methye green, terminal deoxynucleotidyl and the dUTP Nick end labeling technique. Quantitative analysis was done by computer image analysis system. RESULTS: In Group A the injured neurons recovered well morphologically. The imaging analysis showed a result of Group A

[Finite element analysis of DAI animal model caused by nonimpact with half bound head in cats].

This study sought to make a biomechanical analysis of the diffuse axonal injury(DAI) animal model caused by nonimpact with half bound head in cats. A three-dimensional finite element model of cat's head was established. The head of an anesthetized cat was scanned in 2 mm section. The nods and element meshes were signed out according to the geometry of every section. The geometric data were put into the computer and the element mesh body of cat's head was established in vizi CAD system. The maximum stress, minimum stress and von Mises stress were calculated by Super SAP (93ed) finite elemental software when the force was loaded on the right or left side of model in zero section. The analysis showed that the maximum stress appeared in the anterior and posterior loaded point and extended to cranial base in the cranial shell. There was high stress in the brain surface also. Because of cerebellar tentorium, cerebral falx, petrosal bone and sellar process, the stress did not decrease equivalently while approaching the deep brain, but it was distributed in cerebral-cerebellar peduncles, brain stem, corpus callosum and basal ganglia area at high values. The results suggest that the stress caused by rotational force is widespreadly and unequivalently distributed in brain tissue, which is mainly effected by the cerebellar tentorium, cerebral falx and the irregular geometric forms of cranial bone.

Repair effect of Schwann cells modified by microgene pSVPoMcat on injured spinal cord in rats.

OBJECTIVE: To observe the repair effect of Schwann cells (SCs) modified by microgene pSVPoMcat on injured spinal cord in rats. METHODS: Semi-transection injury at the level of T(8) of spinal cord was made with cutting method on 120 Sprague Dawley (SD) rats. Then 40 rats implanted with SCs modified by microgene pSVPoMcat were taken as Group A, 40 rats implanted with simple SCs as Group B and the other 40 rats were taken as the control group (Group C). The functional recovery of the rats was observed through combined behavioral score (CBS) and cortical somatosensory evoked potential (CSEP), and the expression of the glial fibrillary acidic protein (GFAP) was measured with in situ hybridization and immunocytochemistry. At 3 months after operation, the rats were examined with magnetic resonance image (MRI), and the neurofilaments (NF) of the axons were stained with immunohistochemical method. RESULTS: GFAP expression in Group A was significantly lower than that of the other 2 groups. MRI showed that the spinal signals in the injured area recovered fundamentally in Group A, didn't recover in Group B and malacia focus was found in Group C, which was same as the results of NF staining. Wave amplitudes in incubation periods in Group A and Group B tended to recover. It recovered to the normal level in Group A, which was similar to the results of CBS. CONCLUSIONS: SCs modified by microgene pSVPoMcat can inhibit GFAP expression, improve the growth of the axons and the functional recovery of neurons after spinal cord injury.

[Study on expression of beta-NGF in myoblasts transfected by PSVCEP NGF-CAT with Lipofect AMINE].

OBJECTIVE: To gain an understanding of the expression of beta-NGF in myoblasts transfected by PSVCEP NGF-CAT and the transfecting efficiency of Lipofect AMINE. METHODS: PSVCEP NGF-CAT was delivered into cultured myoblasts by Lipofect AMINE. Expression of beta-NGF in the transfected myoblasts was detected by immunocytochemistry. RESULTS: Lipofect AMINE was evidently engulfed by myoblasts at the 6th hour; about 40% myoblasts could be detected with the expression of beta-NGF by immunocytochemistry at the 48th hour. CONCLUSION: PSVCEP NGF-CAT can express beta-NGF in cultured myoblasts, and Lipofect AMINE is a convenient vector for gene transfection with simplicity and efficacy.

[Sequential changes of hypoxia-inducible factor 1 alpha in experimental spinal cord injury and its significance].

OBJECTIVE: To investigate the sequential changes of hypoxia-inducible factor 1 alpha (HIF-1 alpha) in experimental spinal cord(SCI) injury in rats and analyze its potential effects on SCI. METHODS: Static compression model of SCI was employed in this study. Expressions of HIF-1 alpha were measured with immunohistochemical staining. Flow cytometry was used to determine the apoptotic ratio and bcl-2 expressions. RESULTS: HIF-1 alpha began to increase one day after injury, and reached peak at 3-7 days. Two weeks later, it declined significantly. The sequential changes of HIF-1 alpha coincided well with the alterations of apoptotic ratio and bcl-2 content. CONCLUSION: HIF-1 alpha may participate in the secondary ischemic and hypoxic procedures after spinal cord injury and mediate the traumatic apoptosis. Further understanding of HIF-1 alpha may provide new therapeutic regimens for SCI.

Effect of intracranial pressure and cerebral perfusion pressure on outcome prediction of severe traumatic brain injury.

OBJECTIVE: To investigate the influence of intra cranial pressure (ICP) and cerebral perfusion pressure (CPP) on neurological det erioration and outcome of severe traumatic brain injury (STBI). METHODS: A total of 245 patients with severe traumatic brain in jury were studied retrospectively with univariate and multivariate studies to ev aluate the contribution of ICP/CPP to neurological deterioration and outcome. RESULTS: The mortality rates rose from 16.2% in 142 patient s whose course of disease was smooth to 66.7% in 103 patients who suffered f rom neurological deterioration. Correspondingly, the favorable outcome fall from 54.2% in the patients without neurological deterioration to 18.3% in th ose with neurological deterioration. In the patients with clinical evidence of n eurological deterioration, the relative influence of the ICP and the CPP on outc ome was assessed. The most powerful predictors of neurological deterioration was the presence of intracranial hypertension (ICP>30 mm Hg, 1 mm Hg=0.133 kPa). The CPP also had a prognostic power on neurological deterioration when its level less than 60 mm Hg. CONCLUSIONS: It suggests that it's very important to lower the intracranial hypertension and keep the CPP not less than 60 mm Hg during the t reatment of STBI.