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肌肉硬度; 竖脊肌; 信度; 康复训练
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Brief electrical stimulation has been shown to be effective in promoting neuronal regeneration following peripheral nerve injury. These effects are thought to be mediated largely by the upregulation of the expression of brain-derived neurotrophic factor (BDNF) in spinal cord neurons. However, the molecular mechanisms by which electrical stimulation can promote BDNF expression are not known. The mechanism involved in BDNF expression after electrical stimulation was explored in this study. Immunohistochemistry and Western blotting were used to test BDNF expression. Confocal microscopy was utilized to study intracellular Ca(2+) volume. Immunohistochemistry and Western blotting confirmed that brief electrical stimulation increased BDNF expression in spinal cord neurons both in vivo and in vitro. Treatment of cultured neurons with nifedipine, an inhibitor of voltage-gated calcium channels, significantly reduced the BDNF increase produced by electrical stimulation, and an inhibitor of Erk completely abolished the effect of electrical stimulation. Levels of BDNF expression in the presence of the Erk inhibitor were lower that in unstimulated and untreated controls, indicating that Erk activation is required to maintain baseline levels of BDNF. Confocal microscopy using a Ca(2+)-sensitive fluorochrome revealed that electrical stimulation is accompanied by an increase in intracellular Ca(2+) levels; the increase was partly blocked by nifedipine. These findings argue that electrical stimulation increases BDNF expression in spinal cord neurons by activating a Ca(2+)- and Erk-dependent signaling pathways.
Sujet(s)
Facteur neurotrophique dérivé du cerveau/métabolisme , Calcium/métabolisme , Stimulation électrique/méthodes , Extracellular Signal-Regulated MAP Kinases/métabolisme , Neurones/métabolisme , Transduction du signal/physiologie , Moelle spinale/cytologie , Animaux , Cellules cultivées , Femelle , Neurones/cytologie , Rats , Rat Sprague-DawleyRÉSUMÉ
Objective To explore the value of phase-contrast magnetic resonance imaging (PC-MR) in diagnosis of secundum atrial septal defect (ASD) in pediatric patients. Methods Totally 42 patients (aged from 9 months to 15 years) with secundum ASD proved with tansthoric echocardiographic (TTE) were evaluated with PC-MRI. Images of the flow through ASD were obtained with PC-MRI. The distances of ASD rim to superior vena cava (SVC), inferior vena cava (IVC), atrioventricular valves (AVV) and right upper pulmonary vein (RUPV), as well as the entrances of the vena cava and right upper pulmonary vein (RUPV) were assessed. Results The sizes of ASD and distances of ASD rim to the adjacent structures (SVC, RVC, AVV and RUPV) at PC-MRI were well consistent with those of TTE in 42 patients (P<0.001). PC-MRI results in 26 patients correlated well with surgical results (P<0.001). With different velocity encoding, compared with surgical results, measurements of ASD's sizes were more accurate when setting velocity from 50 to 70 cm/s than 90 cm/s. Conclusion The shape of ASD can be virtually depicted with PC-MRI. PC-MRI can accurately assess the defect size, number, rim distances to adjacent structures, therefore providing a new method for depiction of congenital heart anomaly.
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@#Objective To investigate the action of chondrogenesis differentiation of bone marrow stromal cells (BMSCs) transfected with adeno-hTGF-β1. Methods In the experiment group, replication-deficient a denoviruses carrying human hTGF-β1 complementary DNA (adeno-hTGF-β1 was constructed and applied to transfect to the first generation BMSCs. As a control, each BMSCs was transduced with 200 pfu of adeno-LacZ gene. One day after transfer, BMSCs were trypsinized, counted, and 5×105 cells aliuots were spun down at 500 rpm per minute in 15 ml polypropylene conical tubes and then cultured in a defined medium in an incubator at 37℃ for 21 days. The aggregates were harvested at time points to 21 days and assessed by gross observation, histological analyses and immunohistochemical localization of type Ⅱ collagen. Results When harvested at 21 days, each pellet shrinked to spheroid tissue with apearly opalescence in gross morphology and found to be relatively firm. H.E staining showed elongate dlining cells appeared as perichon drium-like cells at the surface. Some nests of cartilage were observed at the substrate of the tissue. Mature chon drocytes were embeded in the lacuna in the experiment group. In addition, Safranin'O staining confirmed the presence of sulfated proteoglycans in the ECM of chondrogenesis region. Immunohistochemical staining revealed the presence of type Ⅱ collagen in chondrogenesis region. By contrast, HE staining showed no evidence of cartilage formation in the control group. They were fibrous tissue with no architectural feature. Safranin'O staining and Immunohistochemical staining showed no evidence of sulfated proteoglycans or typeⅡ collagen expression. Conclusion BMSCs transfected with adeno-hTGF-β1 could induce its chondro-genesis when aggregate cultured in a defined medium in vitro, laying a foundation for the application of hTGFβ1 gene-transfected BMSCs in cartilage tissue engineering.
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BACKGROUND: As a result of immature brain of children and their imperfect blood brain barrier, improper clinical treatment would affect growth and development of children. It is fully important to perform further investigation on immature brain injury induced neurodegeneration.OBJECTIVE: To observe the ultramicrostructure of neurons in homolateral parietal cortex and hippocampus in newborn 7-day SD rat with contusion of parietal cortex.DESIGN: Completely randomized controlled trial.SETTING: Laboratories of Nerve Morphology and Cytobiology, Medical College of Shanghai Jiaotong University; Electron Microscope Room of Institute for Physiology, Chinese Academy of Science.MATERIALS: The experiment was performed in Teaching and Research Section of Anatomy, Laboratories of Nerve Morphology and Cytobiology ofShanghai Second Medical University (Medical College of Shanghai Jiaotong University; Electron Microscope Room of Institute for Physiology of Chinese Academy of Science from October 2002 to June 2003. A total of 19newborn 7-day SD rats were randomly divided into experimental group, operation control group and normal control group with 15, 2 and 2 in each group respectively.METHODS: In experimental group, free-fall device for brain injury was used for establishing model of contusion of parietal cortex in newborn 7-day SD rat. Anesthesia and scalp incision were conducted, without using free-fall device in operation control group. But above procedures were not carried out in normal control group. The changes of ultramicrostructure were observed under transmission electron microscope after routine treatment of electron microscopic samples.MAIN OUTCOME MEASURES: Ultramicrostructure of neurons in homolateral parietal cortex and hippocampus.RESULTS: All the 19 rats entered results analysis. ① There were two sorts of morphological changes in neurons in experimental group. One was evident swelling of dendrites and bodies of neurons, accompanied with the changes of organelles. In the early stage, expansion of endoplasmic reticulum cisterna could be observed and mitochondria became compact and concentrated. Then, vacuolization of endoplasmic reticulum, progressive swelling and vacuolization of mitochondria, dissociation of polysomes from rough endoplasmic reticulum and scattering of them in cytoplasm could be seen. Changes of nucleolus presented after significant changes of cytoplasm. Nuclear chromatin clustered together under karyotheca and arranged as clockface, which were some masses with irregular contours gathering to the center. Axons were almost normal. The other was concentration of cytoplasm and nucleolus with vacuolizations of unequal size in cytoplasm. ②There was no abnormal change in neurons in homolateral parietal cortex and hippocampus both in operation control group and normal control group.CONCLUSION: Swelling of brain cell and concentration of cytoplasm and nucleolus after brain injury play important roles in brain injury-induced neurodegeneration of immature rats.
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BACKGROUND: Learning memory disorder is one of the major manifestations of aging. The model of aging induced by D-galactose is a commonly used animal model in recent years, and long-term D-galactose exposure may cause nerve cell morphological changes in animals.OBJETCIVE: To observe spatial learning memory behavior during Dgalactose-induced aging process in order to further explore in vivo evoked long-term potentiation in hippocampus dentate gyrus and synaptic morphological changes in hippocampal CA3 region.DESIGN: Randomized controlled observation.SETTING: Anatomical Teaching and Research Secti , Shanghai Second Medical University; Department of Physiology, Shanghai Traditional Chinese Medicine University.MATERIALS: The experiment was carried out at the Physiological Laboratory of Shanghai Traditional Chinese Medicine University between August 2000 and April 2001. Totally 22 male Wistar rats of 3-month birth age were included and randomized into normal group and D-galactose group with 11 rats in each group. D-galactose was produced by Shanghai No. 2 Chemical Reagent Factory, Morris water maze was home-made by the Institute of Geriatrics, Shanghai Traditional Chinese Medicine university.METHODS: Rats were subjected to hypodermic injection of 1 mL normal saline every day in normal group, or D-galactose of 800 mg/kg daily for 6consecutive weeks in D-galactose group. Rat spatial learning memory behavior was assessed by the latency of Morris water maze; hippocampal dentate gyrus community potentials evoked by monopulse stimulation on perforating fibers were recordedin vivo; meanwhile, the amplitude of monopulse evoked potentials was determined before and after high frequency stimulation, with the amplitude before high frequency stimulation taken as baseline. Transmission electromicroscope was applied in combination with imaging analysis to observe synaptic morphology and structure in rat hippocampal CA3 region. Water labyrinth latency was compared using the variance analysis of repetitive survey design, t-test was used to compare the differences of peak potential latency of community potentials at various time points after long-term potentiation. Moreover, inducing rate of longterm potentiation was compared by χ2-test, XY-540 type biological imaging processing system was used to analyze electromicroscopic pictures, and all available data were analyzed with t-test.MAN OUTCOME MEASURES: [1] Main outcomes: Changes of Morris water maze latency, as well as inducing rate of long-term potentiation and community potentials. [2] Secondary outcomes: Synaptic morphological and structural changes in hippocampal CA3 region.RESULTS: Totally 22 rats were enrolled in this study, with no one lost during water labyrinth test, but one rat in both normal group and D-galactose group died during electrophysiological experiment. Finally 3 rats were randomly selected from each group for electromicroscopic observation. [1]Comparison of the latency for Morris water maze: In contrast with that of normal group, latency for seeking submarine platform was obviously prolonged in D-galactose group [(14.77±10.10), (51.36±12.45) s, P < 0.05].[2] Comparison of evoked potential in hippocampus dentate before high frequency stimulation: The two groups did not obviously differ in community potential amplitude and community potential latency [(1.05±0.47),(0.91±0.41) mV; (5.46±2.09), (5.38±2.26) ms; P > 0.05]. [3] Inducing rate of long-term potentiation in hippocampal dentate gyrus: Compared to that of normal group, inducing rate in D-galactose group obviously reduced after high frequency stimulation (80%, 20%, χ2=7.20, P < 0.01). [4] Comparison of community potential ratio at different time points after high frequency stimulation: Compared to that of normal group, it was notably reduced in D-galactose group at post-stimulation 20, 30, 60 minutes, respectively (1.104±0.196, 0.919±0.162; 1.354±0.212, 0.999±0.219; 1.236±0.174,0.875±0.311; P < 0.05). [5] Comparison of synaptic struc tural parameters in hippocampal CA3 region: Compared to that of normal group, postsynaptic dense bodies became thickened in hippocampal CA3 region of D-galactose group [(40.60±18.26), (26.35±8.15) nm, P < 0.05], the synapse gap increased [(17.69±6.28), (26.95±5.67) nm, P < 0.05] while synaptic active zone was shortened [(265.13±76.50), (229.13±90.68) nm, P < 0.05].CONCLUSION: Hypodermic injection of D-galactose does harm to rat spatial learning memory by reducing the long-term potentiation, inducing rate in rat hippocampal dentate gyrus, attenuating the increase of long-term potentiation-evoked potential amplitude, and even remarkably changing the synaptic ultrastructure in rat hippocampal CA3 region. It suggests that Dgalactose inhibits the long-term potentiation at hippocampal dentate gyrus and affects synaptic structure in hippocampal CA3 region, which is considered as the basis of spatial learning memory behavioral disorder.
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The segmental distribution of the afferent fibers traversing the stellate ganglia was studied with HRP techinque in 33 cats. The animals were divided into two groups. In one group HRP was injected into the stellate ganglion of one side. Labelled cells were found in ipsilateral spinal ganglia from C_4 to T_9. The majority of these cells (84.49%) were distribued in T_1 to T_5 segments. There is no conspicuous difference between the left and right in respect to the segmental and the pattern distribution of labelled cells. The majority of the labelled cells were medium or small sized (
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Nerve segments were excised from the posterior limb of the adult dog and treated by repeated freezing and thawing for five times. A segment about 5 mm long was removed from the right tibial nerve proximal to the popliteal fossa of each experimental adult rabbit, and 8 mm of nerve segment from the dog prepared as above was transplanted in the gap. Both the proximal and distal ends of the tibial nerve of host rabbits were sutured to the graft nerve of the donor dog. The grafts were excised together with the sutured cut ends of the recipient tibial nerve at 3, 4, 5, 6, 7, 15, 18, and 31 weeks after transplantation. The regenerating nerve fibers were found by light microscope from the proximal end of the right tibial nerve to the graft, and from the graft to the distal part of the tibial nerve at 3, 4, 5, 6, 7, 15, 18 and 31 weeks. Under electron microscope regenerating myelinated and unmyelinated fibers were found to be separate or in fascicle in the graft and the distal segment of the tibial nerve at the above survival time after transplantation. Perineurium was seen surrounding the regenerating nerve fascicles. Neurotubules, neurofilaments and mitochondria were found in the regenerating axons. The diameter of the regenerating myelinated fibers with long survival time after transplatation was thicker than that with short survival time. Repeated freezing and thawing reduced the antigenicity of the heterogenic nerve that it was not rejected after transplantation, and induced the regenerating nerve fibers of the host grow into the graft nerve and extend distally.
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The effect of concanavalin A (Con A) on nerve regeneration in heterograft was done in the present study. A segment about 5mm long was removed from the right sciatic nerve of adult rats. A 8mm of the heterograft nerve segment from the tibial nerve of the rabbit and pretreated by Con A was transplanted into the gap of the severed rat nerve. Regenerating nerve fibers were found from the proximal part of the sciatic nerve into the graft, and also from the graft into the distal part of the sciatic nerve at the 4th,8th and 12th week after transplantation. Regenerating nerve fibers existed separately or clustered into fascicles in the graft,as well as in the distal part of sciatic nerve. Some unmyeli-nated nerve fibers were scattered among the regenerating myelinated fibers. The gastrocnemius muscle was AChE-positive at 8th and 12th week after transplantation. In silver-combined AChE staining section, the regenerating nerve fibers could be seen connecting with the motor endplates. There were regenerating free nerve endings and nerve fascicles in the dermis and epidermis at 8th and 12th week after transplantation. The present study showed that the pretreatment of Con A had benefit to that the regenerating nerve fibers to pass through the heterograft and reinnervated to the targetes.ADepartment of Anatomy,Jiangxi Medical College,Nanchang 330006,China
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Objective To study the effects of panaxydol(PND) upon neurotrophic factors(NTFs) expression in Schwann cell,and to further reveal the mechanisms that underlie these effects. Methods Schwann cells were treated with PND of different concentrations in the culture medium.NTFs expression was examined through immunoiistochemistry assay.The intracellular cAMP level was assessed by radioimmunologic assay. Results There was an increase in NGF expression after PND treatment within the range of 2.5-20.0?mol/L(P