Alterations in Brain Polyribosomal RNA Translation and Lymphocyte Proliferation in Prenatal Ethanol-Exposed Rats

The long-term effects of prenatal ethanol exposure on the properties of brain polysomes and the proliferative responses of lymphocytes to mitogenic stimulation in adult offspring were assessed. Female Sprague-Dawley rats either ingested the control or 6.6% ethanol-containing Lieber-DeCarli liquid diet during the 3rd trimester of pregnancy. Controls were age-matched and pair-fed. At 42 to 72 days of age, ethanol effects were evaluated on the (1) polysomal properties in the cerebral hemispheres, cerebellum, and hippocampal regions of the brain after translation in a messenger RNA (mRNA)-dependent rabbit reticulocyte lysate system and (2) immunologic functions of lymphocytes cultured from spleen cells by measuring their responses to mitogenic stimulation. Results showed long-term adverse effects of in utero ethanol exposure on the polysomal RNA translation in each of the three brain regions tested with free polysomal mRNAs affected more than the bound polysomal mRNAs. Of these, the hippocampal region appeared to sustain the most injurious effects. In addition, a suppression of the mitogen-induced lymphocyte proliferative responses were present under these conditions. The degree of suppression varied with the specific mitogen used. Data suggest that the ethanol effects on the CNS and lymphocyte proliferation are most possibly irreversible, and in the case of the CNS, a post-translational modification by ethanol is indicated. The reduced lymphocyte responses are suggestive of a possible interference by ethanol of the synthesis of interleukin-2 (IL-2) and/or a reduced binding of IL-2 with its receptor (IL-2 receptors).     

磁共振新技术DKI和IVIM在中枢神经系统的研究现状

磁共振成像(MRI)技术在评估脑的解剖结构及功能变化方面得到日益广泛的应用。扩散峰度成像(DKI)是用于量化组织内水分子非高斯运动的磁共振新技术,是扩散成像技术的延伸,对于描绘脑组织微观结构具有独特优势。体素内不相干运动成像(IVIM)是近几年发展起来的无创评价活体组织内分子扩散运动及灌注的MRI新技术。本文对DKI和IVIM的成像原理以及对中枢神经系统的应用价值的研究进展予以综述。     

磁敏感加权成像脑铁含量感兴趣区选择及测量研究

目的探讨苍白球区异常矿物质沉积时,选取不同感兴趣区(region of interest,ROI)(整个苍白球或局部矿物质沉积区域)对铁含量测值的影响,从而为脑组织铁含量测定感兴趣区选择及其测量的便捷性提供依据。材料与方法采用常规磁共振成像和磁敏感加权成像扫描94例健康志愿者,其中苍白球区存在明显矿物质沉积10例,分别选取苍白球整体(A1组)及局部矿物质沉积区域(A2组)为ROI测量灰度值。另外选取性别和年龄相匹配的苍白球区无异常铁含量沉积10例作为对照组(B组)。通过Pearson线性相关分析比较苍白球区有无异常铁含量沉积时的信号值对苍白球区铁含量测量的影响。结果 A1组和A2组灰度值测量相关系数r=0.827(P0.05),整个苍白球区灰度值测量与局部区域灰度值测量具有显著一致性;A1组和B组相关系数r=0.183(P0.05),A2组和B组间相关系数r=0.344(P0.05),说明苍白球区内有无矿物质沉积对灰度值测量影响具有统计学意义。结论通过SWI技术分析含有异常矿物质沉积的苍白球区,选取整个苍白球区作为ROI与只将异常的矿物质沉积区作为ROI反映矿物质沉积趋势具有一致性,对脑铁测量影响不大,因此可以直接选取苍白球整体区域作为ROI测量脑铁含量,方法便捷,值得临床推广应用。     

脑外伤所致精神障碍神经影像学研究进展

脑外伤(traumatic brain injury,TBI)伴发精神障碍损伤机制正逐渐成为认知神经科学研究的焦点。目前对脑外伤后精神障碍的诊断主要依赖临床评估,具体发病机制知之甚少。最近基于影像学的研究发现脑外伤导致的病理改变并非传统观念认为的一过性损伤,其对脑网络功能及属性的破坏可能是终身的,这在一定程度上增加了阿尔茨海默病,创伤性脑病等远期后遗症的患病风险。作者拟对脑外伤出现精神障碍患者影像学改变的研究现状进行综述。     

血流动力学双室模型Extended Tofts Linear在脑胶质瘤DCE-MRI渗透性定量分析的复测性及有效性研究

目的通过重复测量脑胶质瘤动态对比增强磁共振成像(dynamic contrast-enhanced MRI,DCE-MRI)渗透参数:容积转运系数Ktrans、血管外细胞外间隙容积比Ve及对比剂血浆容积Vp,探讨血流动力学双室模型Extended Tofts Linear的复测性(reproducibility)。材料与方法收集经病理证实的脑胶质瘤患者19例(低级别7例,高级别12例),术前均行DCE-MRI检查。由两名工作经验丰富的放射科医师分别使用Extend Tofts Linear模型对DCE-MRI图像进行血管渗透性定量分析,获取病变实性成分的T1加权信号时间-浓度曲线及血流动力学参数Ktrans、Ve及Vp,分别记为测量1、测量2,经统计学分析,分别比较两组各参数在高、低级别胶质瘤中是否存在统计学差异以及后处理模型的复测性。结果测量1、测量2两组高级别胶质瘤的Ktrans值、Ve值及Vp值均高于低级别胶质瘤,差异均有统计学意义(P0.05)。测量1、测量2两组Ktrans值、Ve值及Vp值可重复性比较的组内相关系数(ICC)值分别为0.93、0.809、0.592,均大于0.4。结论血流动力学双室模型Extended Tofts Linear在脑胶质瘤DCE-MRI血管渗透性定量分析具有很好的复测性。     

脑梗死后微血管渗透性改变及出血性转化的预测

目的探讨缺血性脑梗死后急性期和亚急性期微血管渗透性改变及脑梗死后出血性转化(hemorrhagic transformation,HT)的预测。材料与方法收集缺血性脑梗死病人43例,急性期10例,亚急性期33例,进行常规MRI及DCE-MRI扫描。利用药代动力学模型计算容积转运常数Ktrans,比较每一个病人梗死区和对侧正常脑组织的Ktrans值以及出血组和非出血组的Ktrans值有无差异,比较不同时期梗死区强化对预测HT的意义。结果所有病人梗死区Ktrans值较对侧正常脑组织明显增高(P0.05)。10例在急性期有脑实质强化的病人都有继发出血,在亚急性期和慢性期15例病人有继发出血,18例没有继发出血,Fisher's精确检验有统计学意义(P0.05)。与亚急性期HT或没有HT的病人相比,急性期有HT组病人的Ktrans值明显增高(P0.05),但是亚急性期HT和非HT的病人Ktrans值比较没有统计学差异(P0.05)。结论急性期脑实质强化对HT的预测有更高的特异性,且渗透性比亚急性期更高。早期脑实质强化及HT与毛细血管内皮的紧密连接和基底膜损伤有关。后期脑实质强化及HT与侧枝循环的建立有关,DCE-MRI可以定量评估血脑屏障的渗透性,对进一步研究HT的分型提供更科学的依据。     

Therapeutic temperature modulation is associated with pulmonary complications in patients with severe traumatic brain injury

AIM: To examine complications associated with the use of therapeutic temperature modulation(mild hypothermia and normothermia) in patients with severe traumatic brain injury(TBI). METHODS: One hundred and fourteen charts were reviewed. Inclusion criteria were: severe TBI with Glasgow Coma Scale(GCS) 9, intensive care unit(ICU) stay 24 h and non-penetrating TBI. Patients were divided into two cohorts: the treatment group received therapeutic temperature modulation(TTM) with continuous surface cooling and indwelling bladder temperature probes. The control group received standard treatment with intermittent acetaminophen for fever. Information regarding complications during the time in the ICU was collected as follows: Pneumonia was identified using a combination of clinical and laboratory data. Pulmonary embolism, pneumothorax and deep venous thrombosis were identified based onimaging results. Cardiac arrhythmias and renal failure were extracted from the clinical documentation. acute respiratory distress syndrome and acute lung injury were determined based on chest imaging and arterial blood gas results. A logistic regression was conducted to predict hospital mortality and a multiple regression was used to assess number and type of clinical complications. RESULTS: One hundred and fourteen patients were included in the analysis(mean age = 41.4, SD = 19.1, 93 males), admitted to the Jackson Memorial Hospital Neuroscience ICU and Ryder Trauma Center(mean GCS = 4.67, range 3-9), were identified and included in the analysis. Method of injury included motor vehicle accident(n = 29), motor cycle crash(n = 220), blunt head trauma(n = 212), fall(n = 229), pedestrian hit by car(n = 216), and gunshot wound to the head(n = 27). Ethnicity was primarily Caucasian(n = 260), as well as Hispanic(n = 227) and African American(n = 223); four patients had unknown ethnicity. Patients received either TTM(43) or standard therapy(71). Within the TTM group eight patients were treated with normothermia after TBI and 35 patients were treated with hypothermia. A logistic regression predicting in hospital mortality with age, GCS, and TM demonstrated that GCS(Beta = 0.572, P 0.01) and age(Beta =-0.029) but not temperature modulation(Beta = 0.797, ns) were significant predictors of in-hospital mortality [χ2(3) = 22.27, P 0.01] A multiple regression predicting number of complications demonstrated that receiving TTM was the main contributor and was associated with a higher number of pulmonary complications(t =-3.425, P = 0.001). CONCLUSION: Exposure to TTM is associated with an increase in pulmonary complications. These findings support more attention to these complications in studies of TTM in TBI patients.     

振幅整合脑电图对早产儿脑损伤的诊断价值及其影响因素

目的　探讨振幅整合脑电图(aEEG)对早产儿脑损伤(BIPI)的诊断价值及其影响因素。方法　将116例胎龄27~36+6周早产儿纳入研究, 对所有早产儿生后 6 h 内aEEG进行评分; 依据BIPI诊断结果将116例早产儿分为BIPI组(n=63)和非BIPI组(n=53), 采用logistic回归分析对导致BIPI发生的危险因素进行评估; 依据aEEG检测结果再将116例早产儿分为aEEG正常组(n=58)和aEEG异常组(n=58), 对影响早产儿aEEG结果的因素行单因素分析。结果　BIPI组中aEEG异常52 例(83%); 非BIPI组中aEEG 异常6例(11%), 两组aEEG异常率比较差异有统计学意义(P<0.05)。将早产儿依据胎龄27~33+6周和34~36+6周进行划分, BIPI组aEEG评分明显低于同胎龄非BIPI组(P<0.01)。Logistic回归分析显示：小胎龄(<32周)、低出生体重(<1 500 g)、胎盘胎膜及脐带异常和母孕期高血压是导致BIPI发生的高危因素(P<0.05)。aEEG异常组与aEEG正常组在胎龄、出生体重、胎盘胎膜及脐带异常和母孕期高血压4方面比较差异有统计学意义(P<0.05)。结论 导致BIPI发生的危险因素与影响早产儿aEEG结果的因素相一致, 提示aEEG有助于BIPI的早期诊断。     

功能性电刺激对急性脑梗死大鼠运动功能及室管膜下区内源性神经干细胞的影响

目的 观察不同时间点功能性电刺激(FES)对急性脑梗死大鼠神经功能和室管膜下区（SVZ）内源性神经干细胞增殖、迁移及分化的影响。 方法 采用大脑中动脉阻塞(MCAO)法制作急性脑梗死大鼠模型212只,其中128只大鼠符合入选标准,最终108只完成实验。将这108只大鼠按随机数字表法分为对照组、假刺激组和FES组,每组36只,每组再按治疗时间的不同分为治疗1、3、7和14d四个亚组,每亚组9只大鼠。术后第3天开始以表面电极刺激瘫痪侧前肢,治疗强度（约4～5mA）以引起瘫痪侧出现伸腕伸指动作为准,每日1次,每次治疗15min。分别于治疗前和治疗各时间点,采用改良神经功能缺损评分(mNSS)法评定各组大鼠神经功能变化情况;采用免疫组织荧光化学法检测缺血侧脑组织SVZ的BrdU+/GFAP+、BrdU+/DCX+、BrdU+/NeuN+阳性细胞表达的动态改变。 结果 治疗第7天和第14天,FES组的mNSS评分与其余2组比较,差异有统计学意义(P<0.05);治疗第14天,单独行运动功能项目的评分比较,FES组的评分与其余2组比较,差异有统计学意义(P<0.05);FES组大鼠梗死侧SVZ的BrdU+细胞数目在FES治疗第7天达到高峰;FES组BrdU+/GFAP+阳性细胞数目表达在治疗第7天和第14天分别与假刺激组和对照组比较,差异均有统计学意义(P<0.05);BrdU+/DCX+细胞数目随着时间延长增加,在治疗第14天时FES组阳性细胞数目均高于假刺激组和对照组(P<0.05);BrdU+/NeuN+仅在治疗第14天时有少量表达,组间差异无统计学意义（P>0.05）。 结论 FES治疗能够改善急性脑梗死大鼠神经功能,促进SVZ神经干细胞的增殖和分化。     

Cerebral ischemia-induced mitochondrial changes in a global ischemic rat model by AFM

Mitochondria play a central role in cell survival, and apoptotic cell death is associated with morphological changes in mitochondria. Quantification of the morphological and mechanical property changes in brain mitochondria is useful for evaluating the degree of ischemic injury and the neuroprotective effects of various drugs. This study was performed to investigate the changes in brain mitochondria in an 11-vessel occlusion ischemic model treated with magnesium sulfate (MgSO₄), utilizing atomic force microscopy (AFM). Rats were randomly divided into three groups consisting of sham (n = 6), global ischemia (GI, n = 6), and MgSO₄-treated global ischemia (MgSO₄, n = 6). The biophysical properties of brain mitochondria determined from AFM topographic images and adhesion force from force–distance measurements. The mean perimeter of ischemic mitochondria significantly increased to 2,396 ± 541 nm (vs. 1,006 ± 318 nm in control group, P < 0.001). The MgSO₄ treatment during global ischemia reduced the perimeter of ischemic mitochondria (1,127 ± 399 nm, P < 0.001). The other parameters including length, width and area were significantly different than the GI group. Besides, the adhesion force (23.2 ± 3.9 nN) of isolated mitochondria from the MgSO₄ group was close to normal levels (28.5 ± 2.5 nN), compared with that of ischemic ones (17.7 ± 3.3 nN, P < 0.001). To confirm the neuroprotective effects of MgSO₄, we performed Nissl staining. This study suggested that quantitative analysis of mitochondrial changes utilizing AFM could be effective for evaluating neuronal injury and drug effects.