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51.
Elemental composition and water content of myelinated axons and glial cells in rat central nervous system 总被引:1,自引:0,他引:1
The distribution of elements (e.g. Na, Cl, K) and water in CNS cells is unknown. Therefore, electron probe X-ray microanalysis (EPMA) was used to measure water content and concentrations (mmol/kg dry or wet weight) of Na, Mg, P, S, Cl, K and Ca in morphological compartments of myelinated axons and glial cells from rat optic nerve and cervical spinal cord white matter. Axons in both CNS regions exhibited similar water content ( 90%), and relatively high concentrations (wet and dry weight) of K with low Na and Ca levels. The K content of axons was related to diameter, i.e. small axons in spinal cord and optic nerve had significantly less (25–50%) K than larger diameter axons from the same CNS region. The elemental composition of spinal cord mitochondria was similar to corresponding axoplasm, whereas the water content (75%) of these organelles was substantially lower than that of axoplasm. In glial cell cytoplasm of both CNS areas, P and K (wet and dry weight) were the most abundant elements and water content was approximately 75%. CNS myelin had predominantly high P levels and the lowest water content (33–55%) of any compartment measured. The results of this study demonstrate that each morphological compartment of CNS axons and glia exhibits a characteristic elemental composition and water content which might be related to the structure and function of that neuronal region. 相似文献
52.
The aim of this investigation was to establish the relationship between short-term perceived comfort and pressure distribution on the dorsal and plantar surfaces of the foot, while walking in a range of commercially available casual footwear. The study was carried out in the biomechanics laboratory of Manchester Metropolitan University using 15 male subjects without foot pathology. Perceived upper and plantar comfort were measured using a specially designed questionnaire, while dorsal and plantar pressure distributions were measured using a rectangular sensor pad recording at 30 Hz and a Mikro-EMED insole recording at 100 Hz respectively. Analysis of variance tests were used to determine differences in perceived comfort and pressure distribution between three pairs of shoes. The findings of this study suggest that an increase in total plantar force and force-time integral may relate to a decrease in perceived plantar comfort. For the three shoes examined in this study, overall peak plantar pressure, the pressure-time integral, and total plantar area did not appear to be linked to perceived plantar comfort. Findings for the shoe upper indicate that decreased dorsal forces and pressures may be related to decreased upper comfort. These findings suggest that the measurement of pressure distribution at the foot-shoe interface could be a useful tool in identifying the causes of discomfort in footwear. 相似文献
53.
G. Wu S. F. Fan Z.-H. Lu R. W. Ledeen S. M. Crain 《Journal of neuroscience research》1995,42(4):493-503
Prolongation of the action potential duration of dorsal root ganglion (DRG) neurons by low (nM) concentrations of opioids occurs through activation of excitatory opioid receptors that are positively coupled via Gs regulatory protein to adenylate cyclase. Previous results suggested GM1 ganglioside to have an essential role in regulating this excitatory response, but not the inhibitory (APD-shortening) response to higher (μM) opioid concentrations. Furthermore, it was proposed that synthesis of GM1 is upregulated by prolonged activation of excitatory opioid receptor functions. To explore this possibility we have utilized cultures of hybrid F11 cells to carry out closely correlated electrophysiological and biochemical analyses of the effects of chronic opioid treatment on a homogeneous population of clonal cells which express many functions characteristic of DRG neurons. We show that chronic opioid exposure of F11 cells does, in fact, result in elevated levels of GM1 as well as cyclic adenosine monophosphate (AMP), concomitant with the onset of opioid excitatory supersensitivity as manifested by naloxone-evoked decreases in voltage-dependent membrane K+ currents. Such elevation of GM1 would be expected to enhance the efficacy of excitatory opioid receptor activation of the Gs/adenylate cyclase/cyclic AMP system, thereby providing a positive feedback mechanism that may account for the remarkable supersensitivity of chronic opioid-treated neurons to the excitatory effects of opioid agonists as well as antagonists. These in vitro findings may provide novel insights into the mechanisms underlying naloxone-precipitated withdrawal syndromes and opioid-induced hyperalgesia after chronic opiatf addiction in vivo. © 1995 Wiley-Liss, Inc. 相似文献
54.
55.
本文报告了4例涉及椎体及其后部结构的全椎骨肿瘤的外科治疗,介绍了全椎骨切除术的手术方法及手术注意事项。手术采用后路附件切除,上下椎体Steffee钢板内固定,前路椎体切除自体髂骨植骨融合,初步效果满意。本手术难度大、出血多、危险性高,术中采用控制性低血压,以减少出血。 相似文献
56.
Z. Lackovi M. Jakup
evi A. Bunarevi I. Damjanov M. Relja I. Kostovi 《Brain research》1988,443(1-2):199-203
The content of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and norepinephrine (NE) was analysed in 71 human spinal cords obtained post-mortem. The highest content of 5-HT, 5-HIAA and NE was found in the lumbar enlargement of the spinal cord. 5-HT and 5-HIAA content increased from fetal to adult spinal cord whereas the content of NE decreased. Characteristic segmental distribution of measured monoamines was present in adult spinal cord only. In two patients spinal cord lesion led to the reduction in spinal cord content of 5-HT, 5-HIAA and NE and loss of characteristic segmental distribution of these substances. These results are in general agreement with observations on spinal cord of different animal species. 相似文献
57.
颈脊髓压迫模型的建立及意义 总被引:1,自引:0,他引:1
目的 :旨在探索、建立颈脊髓压迫损伤的动物模型 ,并观察、研究其病理学改变过程 ,为临床治疗颈脊髓损伤提供理论依据。 方法 :通过在犬C4 、C5椎间孔置入不锈钢螺钉压迫脊髓 ,成功建立起一种新型不完全性颈脊髓压迫损伤的动物模型 ,并通过光镜和电镜研究创伤后不同时间脊髓的病理改变。 结果 :损伤后动物表现为不完全性瘫痪 ,随时间的推移运动功能逐渐恢复。病理改变结果可分三期 :早期脊髓内出血、水肿及神经元和神经纤维变性 ;中期神经元和神经纤维变性达到高峰 ,胶质细胞增生 ;晚期出现机化和修复 ,部分神经元和神经纤维恢复正常形态。 结论 :颈脊髓不完全性压迫损伤后脊髓功能有恢复的可能 ,临床应进行早期治疗。 相似文献
58.
A. Rimmelin P. L. Clouet S. Salatino P. Kehrli D. Maitrot M. Stephan J. L. Dietemann 《Neuroradiology》1997,39(3):203-206
Extradural arachnoid cysts are uncommon expanding lesions in the spinal canal which may communicate with the subarachnoid
space. Usually in the lower thoracic spine, they may cause symptoms by compressing the spinal cord or nerve roots. We report
cases of thoracic and lumbar arachnoid cysts studied by cystography, myelography, CT and MRI. These techniques showed extradural
cystic lesions containing cerebrospinal fluid, with variable communication with the subarachnoid space, causing anterior displacement
and flattening of the spinal cord.
Received: 3 November 1995 Accepted: 16 April 1996 相似文献
59.
60.
狗脊髓截除自体隐神经大网膜移植的初步观察 总被引:3,自引:0,他引:3
实验用6只狗于T13处切除脊髓8mm,局部用隐神经、大网膜移植。对照组6只狗单纯切除脊髓8mm。术后3个月、6个月实验组动物全部恢复到C/Ⅲ级功能,组织学切片见移植神经有不同程度存活,可记录到股四头肌、胫前肌电位。对照组动物仅达到0/0~A/I织功能,组织学切片见脊髓缺损处为结缔组织,诱电位波形消失。分析了影响脊髓神经功能恢复的原因。 相似文献