寡核苷酸对脊髓损伤后硫酸软骨素蛋白聚糖表达调控的实验研究

目的用人工合成的内切磷硫酰寡脱氧核糖核苷酸(ODN-PSs)对脊髓损伤进行干预,分析硫酸软骨素蛋白聚糖表达,探讨ODN-PSs与神经损伤修复的关系。方法采用改良AllenWD法[1]制成脊髓损伤模型后,再随机分为ODN-PSsXT-1实验组30只和实验对照组30只进行干预实验;利用免疫组化染色,Western blot和RT-PCR方法对细胞表达的硫酸软骨素蛋白聚糖和木糖基转移酶-1(XT-1)mRNA进行分析。结果免疫印迹和RT-PCR分析结果表明,XT-1ODN-PSs可减少减少CSPG蛋白和XT-1基因的表达。结论人工合成XT-1ODN-PSs寡核苷酸对脊髓损伤后硫酸软骨素蛋白聚糖表达有明显的抑制作用,从而有利于损伤神经核突起的再生。     

Methylprednisolone Inhibits the Expression of Glial Fibrillary Acidic Protein and Chondroitin Sulfate Proteoglycans in Reactivated Astrocytes

创伤后的神经胶质增生导致硫酸软骨素蛋白聚糖(CSPG)的显著表达,从而抑制轴突生长和再生。甲基强地松龙(MP),一种合成的糖皮质激素,在急性脊髓损伤(SCI)的治疗中有神经保护作用和抗炎效应。但是,MP对于CSPG在活性胶质细胞中的表达的作用尚不清楚。本文用a-氨基-3-羟基-5-甲基-4-异恶唑丙酸酯(AM-PA)诱导星形胶质细胞再活化,用环噻嗪模拟SCI的兴奋性中毒刺激。AMPA治疗后,星形胶质细胞再活化的标志物-胶质纤维酸性蛋白(GFAP)、CSPG神经聚糖和磷酸盐的表达都显著上调。AMPA治疗星形胶质细胞的条件培养液强烈抑制大鼠背根神经节中神经元的轴突生长,但这种作用能被MP的预处理所逆转。此外,MP下调成年SCI大鼠中GFAP和CSPG的表达,对抗RU486的糖皮质激素受体(GR)和GR si RNA能逆转MP对GFAP和神经聚糖表达的抑制作用。这些结果提示,MP能在兴奋性中毒损伤后通过GR介导的星形胶质细胞再活化下调和GSPG表达抑制来改善神经修复,促进轴突生长。     

Down-Regulation of Neurocan Expression in Reactive Astrocytes Promotes Axonal Regeneration and Facilitates the Neurorestorative Effects of Bone Marrow Stromal Cells in the Ischemic Rat Brain

脑卒中后缺血组织边界形成胶质疤痕,抑制轴突再生。神经蛋白聚糖是一种轴突延长抑制分子,在卒中后胶质疤痕中表达上调。骨髓基质干细胞(BMSCs)可降低胶质疤痕壁的厚度,加速缺血周边区的轴突重塑。为了进一步明确BMSCs在轴突再生中的作用及机制,本文重点研究脑缺血组织中BMSCs对神经蛋白聚糖表达的作用。31只成年雄性Wistar大鼠大脑中动脉阻塞(MCAo)2 h,24 h后从中选择16只给予尾静脉注射3×106鼠BMSCs(BMSCs组),15只注射磷酸盐缓冲生理盐水(对照组)。缺血后8 d处死实验大鼠,免疫染色表明反应性星形胶质细胞是神经蛋白聚糖的原始来源,且BMSCs组缺血半暗带脑组织的神经聚糖表达明显低于对照组,生长相关蛋白43表达高于对照组,这在蛋白印迹分析中得到确认。为了进一步检测BMSCs在星形胶质细胞神经蛋白聚糖表达中的作用,用激光捕获显微切割法从缺血周边区收集单纯的反应性星形胶质细胞。BMSCs组的神经蛋白聚糖基因表达明显下调(n=4/组)。原代培养的星形胶质细胞也表现出相同改变,糖氧剥离的星形胶质细胞再给氧时与BMSCs共培养会抑制神经蛋白聚糖基因的表达上调(n=3/组)。本研究表明BMSCs通过下调梗死周边星形胶质细胞中神经蛋白聚糖的表达来促进轴突再生。     

细胞周期依赖的蛋白激酶抑制剂Olomoucine对脊髓损伤后硫酸软骨素蛋白多糖表达的影响

目的探讨细胞周期抑制剂Olomoucine对脊髓损伤后硫酸软骨素蛋白多糖(CSPGs)表达的影响及意义。方法建立大鼠脊髓半切损伤模型,随机分为假手术组、损伤对照组和Olomoucine干预组,采用免疫印迹分析脊髓损伤后CSPGs的表达;应用免疫荧光技术检测损伤区域胶质纤维酸性蛋白(GFAP)和CSPGs的表达;采用改良Gale联合评分法对大鼠瘫痪后肢进行运动功能评估。结果脊髓损伤后星形胶质细胞明显活化增殖,GFAP和CSPGs的表达显著高于假手术组(P<0.05),010moucine干预可有效下调GFAP和CSPGs的表达(P相似文献   

大麻素对星形胶质细胞谷氨酸释放的影响及机制研究

目的:观察人工合成大麻素HU210对体外培养中脑腹侧被盖(VTA)区星形胶质细胞谷氨酸释放的影响,并探讨抑制星形胶质细胞谷氨酸释放的药物治疗途径。方法:体外培养大鼠VTA脑区星形胶质细胞,RT-PCR及免疫荧光染色检测胶质纤维酸性蛋白(GFAP)及大麻素受体1(CB1R)的表达。将培养的星形胶质细胞分为4组:对照组(培养基中只加入0.2%DMSO),HU210组(培养基中加入3μM HU210),HU210+AM281组(培养基同时加入3μM HU210及3μM AM281)和HU210+Riluzole组(培养基同时加入3μM HU210及3μM Riluzole),各组4孔。干预30 min后,采用谷氨酸检测试剂盒观察各组星形胶质细胞培养基中谷氨酸浓度。再培养VTA脑区星形胶质细胞,分为对照组(培养基中只加入0.2%DMSO)和Riluzole组(培养基中加入3μM Riluzole),干预30 min后,利用Western Blot印迹分析Riluzole干预后谷氨酸转运体-1(GLT-1)表达水平的变化。结果:RT-PCR及免疫荧光染色显示,星形胶质细胞内有广泛CB1R的表达。与对照组比较,HU210组星形胶质细胞谷氨酸的释放显著增加(P<0.01),HU210+AM281组及HU210+Riluzol组星形胶质细胞谷氨酸的释放较HU210组均显著降低(P<0.01);且HU210+Riluzol组星形胶质细胞的GLT-1表达较对照组升高(P<0.05)。结论:HU210可能通过激活星形胶质细胞的CB1R促进星形胶质细胞释放谷氨酸。Riluzole可能通过升高星形胶质细胞的GLT-1的表达,逆转HU210所致的谷氨酸释放。     

何首乌苷对奥沙利铂诱导大鼠星形胶质细胞凋亡的影响

目的探讨何首乌苷保护大鼠星形胶质细胞免于奥沙利铂诱导凋亡的作用及可能机制。方法原代培养大鼠星形胶质细胞,并利用流式检测所培养细胞胶质纤维酸性蛋白的表达情况。利用10μmol/L奥沙利铂处理胶质细胞24 h建立凋亡模型,加入浓度梯度的何首乌苷预处理胶质细胞24 h后与奥沙利铂共同作用24 h,台盼蓝染色法观察细胞存活。随后通过Annexin V-FITC/PI双染法流式检测各组凋亡率和检测Caspase-3的活性水平。进而利用JC-1染色法流式检测细胞线粒体膜电位,并利用实时定量RT-PCR与免疫印迹检测BAX与BCL2的m RNA水平和蛋白表达量。结果培养的大鼠星形胶质细胞表达胶质纤维酸性蛋白率达95%以上。奥沙利铂处理诱导凋亡24 h后,对照组胶质细胞凋亡率及Caspase-3活性上升并降低线粒体膜电位,加何首乌苷处理后凋亡率及Caspase-3活性下降而线粒体膜电位上升。相对于对照组,加入何首乌苷处理后BAX基因的m RNA及蛋白表达水平降低,BCL2基因的m RNA及蛋白表达水平上升。结论何首乌苷能恢复凋亡相关基因BAX与BCL2的平衡,保护大鼠皮质星形胶质细胞的线粒体膜电位,并使胶质细胞免于奥沙利铂诱导的凋亡作用。     

双孔钾通道TREK-1在神经细胞正常及缺氧条件下的表达研究

目的:研究双孔钾通道TREK-1在神经元及星形胶质细胞的表达,及在缺氧时星形胶质细胞中的表达变化。方法:离体培养大鼠皮质神经元和星形胶质细胞,利用免疫荧光染色法观察TREK-1蛋白在神经元和星形胶质细胞的表达分布,对星形胶质细胞进行缺氧干预,实时PCR观察缺氧不同时间TREK-1的表达变化。结果:TREK-1通道在神经元和星形胶质细胞均有表达,缺氧时TREK-1在星形胶质细胞中呈先上升,后逐渐下降的趋势。结论:TREK-1在神经元和星形胶质细胞中均有表达,星形胶质细胞中TREK-1的表达在缺氧损伤中发生动态变化。     

CO中毒迟发性脑病大鼠脑内星形胶质细胞和少突胶质细胞的表达及高压氧治疗对其表达的影响

目的探讨CO中毒迟发性脑病（DNS）大鼠脑内星形胶质细胞和少突胶质细胞的表达情况及高压氧（HBO）治疗对上述两种胶质细胞表达的影响，分析迟发性脑病的发病机制。方法建立DNS大鼠模型，用HE染色观察大鼠脑组织病理学变化，用免疫组织化学方法，采用小鼠抗大鼠神经胶质原纤维酸性蛋白（GFAP）单克隆抗体、小鼠抗大鼠RIP单克隆抗体检测大鼠脑内星形胶质细胞和少突胶质细胞的表达。结果HE染色标本上，正常对照组大鼠脑内细胞形态正常，DNS大鼠脑皮质出现大片疏松区，海马锥体细胞层稀疏，可见点片状坏死；HBO组坏死程度相对较轻。免疫组化结果显示，与对照组比较，DNS组GFAP表达明显增多（P〈0．05），且阳性细胞形态发生改变；RIP表达随损伤时间的推移逐渐减少（P〈0．05）；HBO组GFAP较7d组表达减少（P〈0．05），RIP较7d组表达增多（P〈0．05）。结论星形胶质细胞和少突胶质细胞在DNS的发病过程中起重要作用，高压氧治疗可针对胶质细胞改善患者脑组织损伤程度。     

NG2胶质细胞的研究进展

NG2是一种硫酸软骨素蛋白多糖(chondroitin sulphate peoteoglycan,CSPG),早期发现在成年大鼠脊髓和大脑的一群成熟胶质细胞中表达,根据这些细胞在白质和灰质中的形态特征,把它们命名为原浆型星形胶质细胞(protoplasmic astrocyte)[1].在发育早期脑内培养的胶质细胞中,有一种叫少突胶质-Ⅱ型星形胶质细胞(O-2A cells)的细胞类型也能被NG2抗体标记[2,3].     

磁刺激通过星形胶质细胞磷酸化蛋白影响星形胶质细胞迁移

目的 研究1.0Hz 60%最大刺激强度的磁刺激通过调控星形胶质细胞磷酸化蛋白（PEA-15）对星形胶质细胞迁移的影响。 方法 取第3～4代体外分离培养的大鼠星形胶质细胞,分为对照组、转染组、磁刺激组和转染+磁刺激组。对照组进行阴性siRNA转染,转染组应用化学合成的siRNA进行脂质体瞬时转染,干扰PEA-15的蛋白表达;磁刺激组的星形胶质细胞在铺板24h后接受60%最大强度磁刺激;转染+磁刺激组进行PEA-15的siRNA转染,并给予60%最大强度磁刺激。用细胞划痕试验检测星形胶质细胞的迁移程度,用免疫印迹试验检测PEA-15的蛋白表达和磷酸化水平变化。 结果 ①PEA-15 siRNA的转染效果明显,Western Blot检测与对照组比较,PEA-15的蛋白表达明显降低。②体外划痕实验中,转染组、磁刺激组、转染+磁刺激组的细胞迁移面积分别与对照组比较,其星形胶质细胞迁移程度增加,差异均有统计学意义（P<0.05）。③与对照组相比,磁刺激组的PEA-15磷酸化明显增加。 结论 干扰PEA-15表达后的星形胶质细胞迁移增加明显;磁刺激可通过增强PEA-15磷酸化促进星形胶质细胞的迁移。     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.