神经生长因子的脑保护作用与Caspase-3表达的相关性

目的 研究神经生长因子(NGF)的脑保护时间窗与半胱天冬酶-3(Caspase-3)表达的相关性.方法 采用兔局灶性脑缺血再灌注损伤模型,分别于再灌注后0h、1h、3h和6h将NGF立体定向导入梗死灶周,再灌注72h观察神经功能、梗死体积、灶周凋亡率和Caspase-3表达.结果 再灌注0h、1h和3 h灶周给予NGF,梗死体积分别较对照组下降50.1%、42.5%和35.2%,相应的灶周凋亡率及Caspase-3表达明显下降,神经功能恢复较好,用药越早越明显;再灌注6h给药,则无明显作用.相关分析显示梗死体积变化与Caspase-3表达具有明显相关性(P＜0.05).结论 NGF脑保护治疗时间窗与Caspase-3表达相关,抑制Caspase-3表达可能是NGF介导神经保护作用的机制之一.     

胶质细胞源性神经营养因子对大鼠局灶脑缺血损伤的保护作用

目的 从胶质细胞源性神经营养因子(GDNF)对大鼠局灶脑缺血梗死灶、半胱氨酸蛋白酶(Caspase-3)表达、细胞凋亡等方面的影响,研究其对大鼠局灶脑缺血的作用及其机制。方法 健康雄性Wistar大鼠120只,随机分为GDNF组和生理盐水组,每组又分为假手术组、缺血oh、3h、6h、24h组,采用大脑中动脉线栓模型,于栓塞同时大鼠脑室内分别给予GDNF和生理盐水5μL。检测脑梗死体积百分比、Caspase-3的表达、细胞凋亡等改变。结果 GDNF组脑梗死体积比明显小于生理盐水组;神经元损伤明显轻于生理盐水组,特别是海马区神经元在GDNF组无明显损伤;GDNF组(Caspase-3表达和TUNEL染色阳性细胞数明显少于生理盐水组。结论 GDNF对大鼠局灶脑缺血有保护作用,抑制Caspase-3的表达和细胞凋亡是其保护机制之一。     

神经生长因子对兔局灶性脑缺血再灌注损伤的治疗时间窗及MR影像学评价

目的研究神经生长因子(NGF)对脑缺血再灌注损伤保护作用的有效时间窗,同时利用MR成像技术对其进行评价。方法采用兔大脑中动脉阻断(MCAO)局灶性脑缺血2 h再灌注72 h模型,分别于缺血再灌注0、1、36、h应用微量进样器将NGF立体定向导入梗死灶周,并于再灌注不同时间点应用MR影像学、TTC染色和流式细胞术评价家兔梗死体积、神经功能缺损和凋亡状态。结果缺血再灌注0、13、h组梗死灶周注射NGF后,经MRI检查所测梗死体积分别为(229.9±17.1)(、260.7±24.2)、(314.6±25.3)mm3,与对照组[(468.6±29.7)mm3]比较差异有统计学意义(均P<0.01);缺血再灌注6 h组梗死体积为(441.1±14.8)mm3,与对照组比较差异无统计学意义(P>0.05)。采用TTC染色所测梗死体积与MRI检查结果一致。脑缺血再灌注3 h内注射NGF,其神经功能缺损评分明显降低,凋亡率明显下降;再灌注6 h后注射NGF则无明显作用。结论NGF对兔局灶性脑缺血再灌注损伤的有效时间窗为再灌注损伤3 h内,MR影像学检查可作为定量评价基因疗效的可靠指标。     

白细胞介素8单克隆抗体对大鼠脑缺血再灌注损伤的保护作用

脑缺血再灌注损伤与炎症反应关系密切,白细胞介素8(IL8)作为一种中性粒细胞趋化因子,在脑缺血后炎症损伤中有重要作用[1]。我们设想IL8单克隆抗体(简称IL8单抗)可能对脑缺血再灌注损伤具有保护作用,在建立脑缺血再灌注模型基础上,侧脑室注射IL8单抗,通过观察脑梗死表1各组大鼠脑梗死灶体积及TUNEL、Bcl2及Bax阳性细胞数分组鼠数梗死灶体积(mm3)TUNELBcl2Bax生理盐水对照组6210.26±25.5845.82±7.0322.97±5.6470.16±8.54IL8单抗0.5μg组6207.25±28.5944.92±7.1124.46±6.3868.26±8.43IL8单抗1μg组6166.29±31.7338.87±7.1…     

硫辛酸对大鼠脑缺血再灌注损伤的神经保护作用

目的研究硫辛酸对大鼠局灶性脑缺血再灌注损伤的保护作用,进一步探讨其机制。方法 54只雄性清洁SD大鼠按照随机原则平均分成3组:假手术组(18只)、脑缺血再灌注组(对照组18只)、脑缺血再灌注+硫辛酸治疗组(治疗组18只)。大鼠大脑中动脉局灶性缺血2 h(MCAO),再灌注24 h。治疗组在再灌注同时经颈外静脉给予硫辛酸20 mg/kg,假手术组和对照组给予相同体积的溶媒。采用TTC染色法检测大鼠脑组织梗死体积;采用RT-PCR法检测大鼠脑组织TNF-α的表达;采用TUNEL法检测大鼠脑组织凋亡细胞数。结果与假手术组相比,对照组和治疗组大鼠脑组织梗死体积,TNF-α的表达和凋亡细胞数均明显增加(均P0.05)。与对照组相比,治疗组大鼠脑组织梗死体积,TNF-α的表达以及凋亡细胞数均明显减少(均P0.05)。结论我们的研究结果表明,硫辛酸对大鼠脑缺血再灌注损伤具有保护作用,可能机制为减轻脑缺血再灌注引起的炎症反应和细胞凋亡。     

细胞外信号调节激酶在实验性脑缺血损伤皮层区的动态时空变化

目的探讨细胞外信号调节激酶(ERK)在局灶性脑缺血/再灌注损伤梗死灶周皮层区的动态时空变化及其作用机制。方法建立兔大脑中动脉阻断(MCAO)局灶性脑缺血再灌注模型,应用免疫组化检测ERK1在脑缺血2h再灌注不同时间灶周皮层的动态表达规律,同时应用免疫组化和流式细胞术检测细胞凋亡状态的动态变化。结果免疫组化分析显示,缺血2h再灌注灶周皮层区1hERK1表达开始增多,6h数目明显增多,3d达高峰,然后逐渐下降,14d回落到基线水平,其阳性细胞数分别为0.22±0.02、0.25±0.02、0.42±0.04、0.14±0.02。其表达时程变化与灶周皮层凋亡的变化相一致。结论脑缺血损伤诱导ERK表达增强,ERK在介导神经细胞凋亡和缺血性损伤中起重要作用。这为脑缺血治疗提供了新的思路。     

依达拉奉对脑缺血再灌注损伤保护作用机制的研究

目的 探讨依达拉奉对脑缺血再灌注损伤的保护机制.方法 将45只健康雄性Wistar大鼠随机分为假手术组、生理盐水对照组、依达拉奉干预组各15只,采用线栓法制作大鼠大脑中动脉缺血模型,脑缺血2h再灌注即刻及12h干预组给予依达拉奉3mr/kg,对照组给予等量生理盐水分别腹腔注射.于24h后断头取脑,免疫组化法测细胞色素C(Cyt C)、半胱氨酸蛋白酶-3(Caspase-3),TUNEL法检测神经细胞凋亡,化学比色法测MDA、SOD,TTC染色测梗死体积.结果 假手术组无梗死现象,免疫反应阳性细胞及凋亡细胞亦少见.依达拉奉十预组与生理盐水对照组相比,Cyt C阳性细胞数、Caspase-3阳性细胞数及凋亡细胞数均明显减少,MDA含量减少,SOD活性有所恢复,差异均有统计学意义.生理盐水对照组可见明显大脑中动脉供血区梗死灶,依达拉奉干预组亦可见到梗死灶,与对照组比梗死体积占全脑体积的百分比明显缩小(t=6.576,P＜0.01).结论 依达拉奉有自由基清除作用,减少了Cyt C的释放,抑制了细胞凋亡,并缩小了梗死体积;依达拉奉可能通过线粒体途径抑制细胞凋亡.对脑缺血再灌注损伤有保护作用.     

核转录因子-κB在局部脑缺血及再灌注损伤后大鼠脑细胞中的表达及N-乙酰半胱氨酸的干预作用

目的　研究核转录因子- κB(nuclearfactorkappaB, NF -κB)在局部脑缺血及再灌注中的作用及N -乙酰半胱氨酸(NAC)预处理的影响。方法　采用大鼠大脑中动脉线栓模型,分为假手术组、6h及24h缺血再灌注组、相应NAC干预组。应用免疫组化法观测NF -κB的表达情况,红四氯氮唑染色测定各组脑梗死体积,脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(TUNEL)检测细胞凋亡。结果　(1)缺血及再灌注后NF- κBp65明显从胞质转移到胞核。NAC干预组[缺血6h及24h再灌注组p65阳性细胞率分别为( 0 .462% ±0 .022% )和( 0 .452% ±0 .015% ) ]较相应生理盐水组[ (0. 563%±0 .028% )和(0 .554%±0 .013% ) ]p65核表达减少(P<0 .01)。(2)缺血6h及24h再灌注NAC干预组梗死体积百分比分别为(8 .39%±2 .54% )和(24. 54%±6 .02% )。相应生理盐水组为(15 .50%±4 .18% )和(32. 22%±3 .99% )。缺血24h组较缺血6h组梗死灶增大,使用NAC各组较注射生理盐水组梗死体积明显缩小(P<0. 01)。(3)NAC预处理组较生理盐水组凋亡细胞减少(P<0 .01)。结论　局灶脑缺血及再灌注能使NF- κBp65活化,参与脑缺血及再灌注损伤。NAC可抑制p65表达,减轻神经损伤,具有脑保护作用。     

神经生长因子对兔局灶性脑缺血再灌注神经功能修复的影响和MR影像学评价

目的:研究神经生长因子(NGF)对兔局灶性脑缺血再灌注损伤神经功能修复的影响,并利用MR成像技术进行评价。方法:采用兔大脑中动脉阻断(MCAO)局灶性脑缺血再灌注模型,分别在缺血2h再灌注损伤后0、1、3和6h应用微量进样器将NGF立体定向导入梗死灶周,于再灌注72h,应用MR影像学、TTC染色和流式细胞术评价兔梗死体积、水肿体积、表观弥散系数(ADC)及神经功能缺损和凋亡状态。结果:缺血再灌注0h、1h、3h和6h灶周给予NGF,梗死体积分别比对照组下降50.1%、48.4%、37.6%和13.7%。同时再灌注3h内应用NGF水肿体积、神经功能缺损评分、灶周凋亡率及caspase-3含量明显下降,梗死中心区及灶周ADC比率(ADCR)升高;再灌注6h后给药,则无明显作用。相关分析显示各组灶周ADCR与灶周凋亡率具有明显负相关。结论:NGF对兔局灶性脑缺血再灌注损伤有保护作用,抑制caspase-3活性的表达和细胞凋亡是其保护机制之一,MR影像学检查可作为定量评价基因疗效的可靠指标。     

胰岛素样生长因子-1对大鼠脑缺血再灌注损伤的作用机制研究

目的观察尾静脉注射胰岛素样生长因子-1(IGF-1)时大鼠脑缺血再灌注损伤的影响，探讨IGF-1的作用机制。方法TTC染色测脑梗死体积，光镜检查细胞损伤变化．免疫组化法测Caspase-3阳性表达。结果与缺血再灌注组相比，IGF-1灶性脑缺血再灌注损伤有保护作用，在脑缺血损伤时IGF-1能通过血脑屏障，IGF-1可通过抑制神经细胞调亡发挥作用。     

Denervation study of synapses of organ of corti of old world monkeys

Fine structural characteristics of synapses in the spiral organ of Corti were examined, with reference to differences between inner and outer haircell systems, and to location of neurons of origin of efferent axons. Surgical interruption of crossed olivocochlear bundle, of vestibular nerve, of facial nerve, and excision of superior cervical ganglia were used to determine the pathways of efferent axons. Interruption of the vestibular nerve near the brainstem results in degeneration of all efferent terminals on outer hair cells. Mid-line lesions at, and caudal to, the facial colliculus result in degeneration of about half of these efferent terminals. Efferent synaptic bulbs to the inner hair-cell system are small, of the order of one micron, and form type 2 junctions with afferent dendrites. They tend to have more large dense-core vesicles (about 80 nm) than the large efferent terminals of the outer hair-cell system, and appear to be the terminals of axons in the habenula perforata, which exhibit varicosities laden with large dense core vesicles. The varicosities are unaffected by excision of the superior cervical ganglia. So far as our material can reveal, it appears that the varicosities in the habenula perforata do not survive vestibular root interruption, nor do the efferent processes in the internal spiral bundle or at the base of inner hair cells. Most interestingly, the afferent processes of the inner hair-cell system, as identified for example by their relation to pre-synaptic bodies in the inner hair cells, are subject to a trans-synaptic reaction after severance of the vestibular root. They undergo a dramatic cytological transformation, characterized by increase of volume, engorgement with microtubules, microfilaments, microvesicles of various sizes, and clusters of lysosomes. Thus, both the efferent and afferent terminals of the inner hair-cell system show marked cytological differences from the corresponding terminals of the outer hair cell system.     

Mechanism of action of tubocurarine on nicotinic cholinoreceptors of neurons of the sympathetic ganglia of rats

Tubocurarine (Tc) effect on membrane currents elicited by acetylcholine (ACh) was studied in isolated superior cervical ganglion neurons of rat using patch-clamp method in the whole-cell recording mode. The "use-dependent" block of ACh current by Tc was revealed in the experiments with ACh applications, indicating that Tc blocked the channels opened by ACh. Mean lifetime of Tc-open channel complex, tau, was found to be 9.8 +/- 0.5 s (n = 7) at -50 mV and 20-24 degrees C. tau exponentially increased with membrane hyperpolarization (e-fold change in tau corresponded to the membrane potential shift by 61 mV). Inhibition of the ACh-induced current by Tc (3-30 microM/1) was completely abolished by membrane depolarization to the level of 80-100 mV. Inhibition of ACh-induced current was augmented at increased ACh doses. It is concluded that the open channel block produced by Tc is likely to be the only mechanism for Tc action on nicotinic acetylcholine receptors in superior cervical ganglion neurons of rat.     

The effect of age of onset of PD on risk of dementia

Background Dementia occurs in the majority of patients with Parkinson’s disease (PD). Late onset of PD has been reported to be associated with a higher risk for dementia. However, age at onset (AAO) and age at baseline assessment are often correlated. The aim of this study was to explore whether AAO of PD symptoms is a risk factor for dementia independent of the general effect of age. Methods Two community-based studies of PD in New York (n = 281) and Rogaland county, Norway (n = 227) and two population-based groups of healthy elderly from New York (n = 180) and Odense, Denmark (n = 2414) were followed prospectively for 3–4 years and assessed for dementia according to DSM-IIIR. All PD and control cases underwent neurological examination and were followed with neurological and neuropsychological assessments. We used Cox proportional hazards regression based on three different time scales to explore the effect of AAO of PD on risk of dementia, adjusting for age at baseline and other demographic and clinical variables. Findings In both PD groups and in the pooled analyses, there was a significant effect of age at baseline assessment on the time to develop dementia, but there was no effect of AAO independent of age itself. Consistent with these results, there was no increased relative effect of age on the time to develop dementia in PD cases compared with controls. Interpretation This study shows that it is the general effect of age, rather than AAO that is associated with incident dementia in subjects with PD. Received in revised form: 22 December 2005     

Limits of deinstitutionalization--perspectives of relatives of psychiatric patients

After a hopeful beginning, the social process of the reintegration of those with severe mental illness has come to a standstill. I am led to wonder whether "the community" really wants to live together with people suffering from severe mental illness, and if so, how closely? As long as the medical treatment of mental illness provided by the general practitioners is fundamentally deficient, as they are not able to prescribe the necessary interventions--such as out-patient psychiatric nursing, and service providers in the out-patient sector are content with offering increasingly intensive forms of care for the less seriously ill at the cost of the Social Welfare System--the reintegration of those with serious mental illness remains an illusion--which is mainly to the benefit of providers of residential care in homes and hostels.