脑白质疏松症文献计量分析

目的了解最近十年脑白质疏松症的研究现状及发展趋势。方法利用中国生物医学文献数据库,用主题词和关键词检索出2005～2014年国内、外发表有关脑白质疏松症中、英文论文,应用文献计量学的方法对其进行统计学分析。结果检索出国内文献546篇,国外文献584篇,文献呈逐年增长趋势;文献涉及40个相关学科,列出前12个研究热点;国内脑白质疏松症研究的重要期刊有《中华老年心脑血管病杂志》、《中国实用神经疾病杂志》、《中华神经医学杂志》、《中华脑血管病杂志》及《中国老年学杂志》等;我国脑白质疏松症研究的科研力量主要分布在北京、广东及山东等地。结论应用文献计量学方法了解国内外脑白质疏松症研究状况,为临床及科研工作者提供重要的参考。脑白质疏松症有很多研究前景;近十年我国脑白质疏松症研究方向与国外接近,但某些领域如脑白质疏松症病理生理学、遗传学方面较滞后。     

脑内五羟色胺与干扰素镇痛

由侧脑室或在中脑导水管周围灰质内微量注射入白细胞α-干扰素可以引起大鼠痛阈明显上升,但脑内5-HT和5-HIAA均无变化。看来干扰素的镇痛作用和脑内5-HT递质无关,它可能是不经过5-HT的释放也不和吗啡受体结合起作用的另一类型的镇痛物质。     

电刺激兔中脑导水管周围灰质对内脏躯体反射和脑脊液中亮氨酸脑啡肽含量的影响

电刺激家兔中脑导水管周围灰质(PAG),观察对内脏躯体反射(VSR)腹肌肌电的影响,用放射免疫方法测定中脑导水管脑脊液中亮氨酸脑啡肽(LEK)样免疫活性物质含量变化。结果:电刺激PAG明显抑制VSR腹肌肌电,平均抑制率为52.3±4.1％,有1min后作用;电刺激中脑顶盖(TM)区对VSR腹肌肌电无抑制作用。电刺激PAG时中脑导水管脑脊液中LEK样免疫活性物质含量明显增加,其变化率与VSR腹肌肌电抑制率呈正相关。本文还讨论了两者可能的关系。     

磁共振弥散张量成像在监测鼻咽癌颞叶放射性损伤中的应用

目的由于鼻咽癌发生具有区域性的特点,目前大样本的综合性研究较少,也缺乏放疗后的纵向对比研究。研究鼻咽癌患者放疗前后不同阶段颞叶白质水分子的弥散特征,探讨放疗对颞叶白质水分子弥散的影响,对放射性损伤的监测提供量化指标。方法鼻咽癌患者放疗前或放疗后行头颅常规MR及弥散张量成像(diffusion tensor imaging,DTI)检查的患者共204例,其中放疗前患者44例,放疗后患者160例。测量所有患者双侧颞叶白质的各向同性表现弥散系数(isotropicapparent diffusion coefficient,ADCiso)值和部分各向异性指数(fractional anisotropic,FA)值,并进行纵向对比分析。结果放疗后双侧颞叶白质的ADCiso值和FA值均下降,放疗后3～5个月变化最明显,随时间延长,6个月以后ADCiso值和FA值有回升趋势。结论 DTI可反映放疗后颞叶白质水分子的弥散特点,有助于监测放射线的损伤程度,以及了解其修复过程的变化规律。     

四种污染源气体颗粒物对大鼠血清肌红蛋白和脑钠肽的影响

【摘要】 目的 观察四种不同污染源气体颗粒物对大鼠血清肌红蛋白和脑钠肽水平的影响。方法 将70只成年SD大鼠随机分为对照组10只、汽车尾气组15只、煤烟组15只、燃烧秸秆组15只和自然空气组15只;按1mg/ml的相同的浓度气管内分别滴注汽车尾气、煤烟、燃烧秸秆、自然空气颗粒物悬液每天1次,一次01ml,连滴10天后,采用化学发光法动态检测5组的血清肌红蛋白（Mb）和脑钠肽（BNP）水平;计算HM/BM;CCK 8法检测大鼠心肌细胞的存活率,并观察心肌细胞的病理变化。结果 各研究组大鼠血清Mb的水平均有所升高,均在一定时间内达到峰值。血清中BNP水平也存在此类波动变化,BNP达到峰值的时间及恢复正常水平的时间比Mb水平晚,但升高的幅度大。汽车尾气组、煤烟组和自然空气组大鼠HM/BM明显升高,出现了不同程度的心肌细胞浸润、水肿、变性、坏死、纤维化;心肌细胞存活率明显下降;秸秆组大鼠HM/BM变化不明显,心肌病理出现了轻度的心肌细胞水肿、变性,HM/BM无明显升高,心肌细胞存活率下降不明显。结论 高浓度的汽车尾气、煤烟、燃烧秸秆、自然空气颗粒均可以引起大鼠的心肌损害。检测大鼠血清中肌红蛋白(Mb)和脑钠肽 (BNP)的水平对判断污染物对大鼠心肌损害程度具有重要意义。     

Src激酶在正常发育和未成熟大鼠缺氧缺血脑白质损伤中的表达变化

目的 研究大鼠正常发育脑中和缺氧缺血性脑白质损伤中Src激酶活化的表达.方法 对出生后第3天SD大鼠幼仔进行右颈总动脉结扎,然后进行2.5 h缺氧(6％氧气)造模.通过苏木精-伊红(HE)染色、蛋白免疫印迹和免疫荧光染色观察神经病理学改变.收集出生后6、10、17天对照组和缺氧缺血(hypoxia-ischemia,H...     

Cardiac oxidative stress and dysfunction by fine concentrated ambient particles (CAPs) are mediated by angiotensin-II

Inhalation exposure to fine concentrated ambient particles (CAPs) increases cardiac oxidants by mechanisms involving modulation of the sympathovagal tone on the heart. Angiotensin-II is a potent vasoconstrictor and a sympatho-excitatory peptide involved in the regulation of blood pressure. We hypothesized that increases in angiotensin-II after fine particulate matter (PM) exposure could be involved in the development of cardiac oxidative stress. Adult rats were treated with an angiotensin-converting enzyme (ACE) inhibitor (benazepril^®), or an angiotensin receptor blocker (ARB; valsartan^®) before exposure to fine PM aerosols or filtered air. Exposures were carried out for 5 hours in the chamber of the Harvard fine particle concentrator (fine PM mass concentration: 440 ± 80 μg/m³). At the end of the exposure the animals were tested for in situ chemiluminescence (CL) of the heart, thiobarbituric acid reactive substances (TBARS) and for plasma levels of angiotensin-II. Also, continuous electrocardiogram (ECG) measurements were collected on a subgroup of exposed animals. PM exposure was associated with statistically significant increases in plasma angiotensin concentrations. Pre-treatment with the ACE inhibitor effectively lowered angiotensin concentration, whereas ARB treatment led to increases in angiotensin above the PM-only level. PM exposure also led to significant increases in heart oxidative stress (CL, TBARS), and a shortening of the T-end to T-peak interval on the ECG that were prevented by treatment with both the ACE inhibitor and ARB. These results show that ambient fine particles can increase plasma levels of angiotensin-II and suggest a role of the renin–angiotensin system in the development of particle-related acute cardiac events.     

Deformation of the corona radiata and internal capsule in normal pressure hydrocephalus

Background and purposeThe pathophysiology of the clinical manifestations in normal pressure hydrocephalus (NPH) remains obscure. Ventricular dilatation could generate forces on the paracentral fibers of the corona radiata (CR), hence interfering with their function and producing the classical clinical triad. The analysis of the regional displacement and deformation of the white matter bundles, forming the corona radiata and internal capsule, may clarify the relationship between ventricular dilatation and clinical manifestations in NPH.MethodAn experimental finite element (FE) analysis was used to simulate ventricular dilatation in 3 dimensions (3D) and to calculate the strain and deformation on the surrounding parenchyma. Magnetic resonance diffusion tensor imaging-based white matter tractography was then applied to retrieve the displacement and deformation exerted along various fiber bundles of the corona radiata and internal capsule. Anterior and posterior limb displacements and elongations were compared using a paired samples t-test.ResultsThe internal capsule, hence the corona radiata, of each cerebral hemisphere was segmented into anterior and posterior limbs. Mean displacements and elongations were calculated for each limb. Mean displacement was significantly larger in the anterior limb whereas mean deformation was larger in the posterior limb (P < 0.01).ConclusionThe present simulation demonstrates that ventricular dilatation does not have a homogeneous effect on the periventricular fibre tracts, with a particular load on the corticospinal tract. The affection of this tract remains thereby a potential factor in the generation of the NPH gait disorders.     

An insight into electrical resistivity of white matter and brain tumors

BackgroundThere is a lack of information regarding electrical properties of white matter and brain tumors.ObjectiveTo investigate the feasibility of in-vivo measurement of electrical resistivity during brain surgery and establish a better understanding of the resistivity patterns of brain tumors in correlation to the white matter.MethodsA bipolar probe was used to measure electrical resistivity during surgery in a prospective cohort of patients with brain tumors. For impedance measurement, the probe applied a constant current of 0.7 μA with a frequency of 140 Hz. The measurement was performed in the white matter within and outside peritumoral edema as well as in non-enhancing, enhancing and necrotic tumor areas. Resistivity values expressed in ohmmeter (Ω1m) were compared between different intracranial tissues and brain tumors.ResultsNinety-two patients (gliomas WHO II:16, WHO III:10, WHO IV:33, metastasis:33) were included. White matter outside peritumoral edema had higher resistivity values (13.3 ± 1.7 Ω1m) than within peritumoral edema (8.5 ± 1.6 Ω1m), and both had higher values than brain tumors including non-enhancing (WHO II:6.4 ± 1.3 Ω1m, WHO III:6.3 ± 0.9 Ω1m), enhancing (WHO IV:5 ± 1 Ω1m, metastasis:5.4 ± 1.3 Ω1m) and necrotic tumor areas (WHO IV:3.9 ± 1.1 Ω1m, metastasis:4.3 ± 1.3 Ω1m), p=<0.001. No difference was found between low-grade and anaplastic gliomas, p = 0.808, while resistivity values in both were higher than the highest values found in glioblastomas, p = 0.003 and p = 0.004, respectively.ConclusionsThe technique we applied enabled us to measure electrical resistivity of white matter and brain tumors in-vivo presumably with a significant effect with regard to dielectric polarization. Our results suggest that there are significant differences within different areas and subtypes of brain tumors and that white matter exhibits higher electrical resistivity than brain tumors.