MDR1 shRNA对人脑胶质瘤干细胞多药耐药性实验研究

目的构建多药耐药基因（MDR1）的短发卡RNA表达质粒，并检测其对胶质瘤干细胞药物敏感性的作用。方法培养脑胶质瘤干细胞；根据MDR1的DNA序列设计shRNA，用Siportxp-1脂质体法转染胶质瘤干细胞。分别采用定量聚合酶链反应（PCR）和Westernblot检测转染前后MDR1mRNA和蛋白表达情况；使用活细胞计数试剂盒（CCK-8）对转染后细胞进行药物敏感性试验，评价shRNA对多药耐药性的逆转作用。结果成功构建MDR1shRNA表达质粒，转染组MDR1mRNA表达水平有所下降（P〈0．05），转染5d组下降最明显；RT—PCR结果显示MDR1mRNA水平降低，第3、5、7d抑制率分别为78．46％±14．17％，82．02％±11．87％，79．5％±13．27％。Westernblot结果显示：shRNA转染组P-糖蛋白（P-gp）的表达降低，第3、5、7d抑制率分别为58．1％±6．5％，39．5％±5．2％，45．8％±8．6％；而药敏实验显示：阿霉素、长春新碱对转染MDRIshRNA的胶质瘤干细胞的半数抑制浓度（IC50）均有不同程度降低，且出现凋亡峰（P〈0．05）。结论MDR1短发卡RNA可在转录后水平对多药耐药进行调节，下调MDR1基因表达，提高药物敏感性，诱导细胞凋亡。     

核糖核酸干扰抑制P-糖蛋白在大鼠耐药星形胶质细胞中过度表达

目的 利用腺病毒载体介导的短发夹RNA(shRNA)抑制大鼠多药耐药基因mdr1b及其编码的P-糖蛋白(Pgp)的表达,探讨其改善癫疴耐药现象的可行性.方法 通过同源重组方法构建腺病毒,表达针对mdr1b的shRNA,感染马桑内酯诱导的耐药星形胶质细胞模型.实时定量逆转录-聚合酶链反应(RT-PCR)和Western blot法分别检测感染5 d内细胞mdr1b和Pgp的表达,流式细胞术检测罗丹明泵出率.结果 得到6×1010pfu/ml滴度的重组腺病毒,转染星形胶质细胞后,细胞mdr1b和Pgp表达明显被抑制,干扰率达94%(P<0.01).Ads-EGFP-shRNA1-U6感染组细胞罗丹明泵出率15.8%,明显低于对照组(56.2%,F=127.5,P<0.05).结论 成功构建针对大鼠mdr1b的RNAi腺病毒载体,并在体外证实其对大鼠mdr1b表达的高效抑制作用,为进一步探索难治性癫癎的基因治疗奠定基础.     

脊髓源星形胶质细胞GFAP表达抑制真核表达载体构建及最佳短发夹样RNA分子筛选

目的构建并筛选大鼠胶质原纤维酸性蛋白（GFAP）表达抑制短发夹样RNA（shRNA）真核表达载体。方法针对GFAP基因全编码序列设计并合成三对9bp茎环结构、19bp干扰序列特异性shRNA模板，体外定向克隆构建特异性重组质粒真核表达载体；通过体外大鼠脊髓源星形胶质细胞GFAP表达抑制模型，脂质体介导RNA干扰分子转染，实时荧光定量RT—PCR及Wesem blot技术观察RNA干扰后原代星形胶质细胞GFAP表达抑制效果．筛选最佳GFAP表达干扰抑制真核表达载体。结果序列测定证实GFAP—shRNA重组质粒真核表达载体构建成功，三对shRNA模板在mRNA及蛋白表达水平抑制靶基因表达效率分别为81％、63％、56％。结论高效率的GFAP—shRNA真核表达载体在大鼠原代星形胶质细胞GFAP表达抑制模型中能高效抑制GFAP基因表达，为后续多靶点RNA干扰技术在脊髓损伤胶质瘢痕抑制基因治疗中的应用奠定了前期基础。     

能合成和分泌GABA的永生化星形胶质细胞的构建

目的 构建能合成和分泌GABA的永生化星形胶质细胞。方法 在原代培养的大鼠星形胶质细胞内转入猴肾病毒40大T抗原基因（si mian virus40large T antigen gene，SV40Tag）使其永生化（这一部分由同济医院麻醉科田玉科教授实验室完成），并在这些细胞内转入含谷氨酸脱羧酶65亚型（glutamate decaxrboxylase65，GAD65）目的基因质粒，对照组转染含β-gal（β-半乳糖苷酶，对照质粒）质粒；应用免疫组化及Western-blot方法检测转染后细胞内GAD65的表达水平；应用毛细管电泳法检测这些细胞内外的氨基丁酸（GABA）含量；用全细胞膜片钳记录构建细胞的GABA电流。结果 与转染β-gal的对照组比较，转染GAD65的实验组细胞在具备胶质细胞特性之外，能稳定表达GAD65，细胞内的GAD65含量明显增加；同时细胞内的GABA含量明显高于对照组；实验组细胞外液GABA的浓度明显高于对照组；实验组和对照组均能记录到GABA电流，说明构建细胞功能完善。结论 永生化的星形胶质细胞中转入GAD65质粒后具备胶质细胞特性，构建细胞能稳定表达GAD65，并且能合成和分泌GABA。     

谷胱甘肽S-转移酶π、DNA拓扑异构酶Ⅱ及P-糖蛋白在难治性癫痫患者脑内的表达

目的 探讨谷胱甘肽S-转移酶π（GST-π）、DNA拓扑异构酶Ⅱ（TopoⅡ）及P-糖蛋白（P-gp）在难治性癫痫（RE）患者脑内的表达及意义。方法 32例RE患者手术切除标本，采用免疫组化方法检测GST-π、TopoⅡ及P-gp表达。8例脑血管畸形患者作为对照。结果 对照组正常脑组织内星形胶质细胞及血管内皮细胞中有少量GST-π表达（2．2），癫痫组GST-π表达明显增强（10．9，P〈0．05）。TopoⅡ在对照组中无表达，癫痫组2例标本有少量表达（0．4，P〉0．05）。对照组中P-gp只在脑内血管内皮细胞中少量表达，癫痫组P-gp则在星形胶质细胞及血管内皮细胞中大量表达（12．9，P〈0．01）。结论 GST-π、P-gp在RE患者脑内表达可能与患者对抗癫痫药耐药有关。     

siMDR1基因转染人类BT325胶质瘤细胞系的表达

目的探讨siMDR1基因转染人类胶质母细胞瘤细胞BT325后细胞的表达能力。方法设计并合成siRNA质粒,取培养对数期生长良好的胶质母细胞系BT325,传代培养。将阳离子脂质体(Lipofectamine 2000)和质粒MDR1 DNA按比例共转染。瞬时对转染成功的细胞系应用抗性药物-嘌呤霉素进行筛选,筛出稳定的细胞系后,分别在荧光显微镜下分析转染情况。通过免疫细胞化学染色及图像分析对瞬时转染和稳定转染的BT325细胞进行检测,确定MDR1基因产物P-糖蛋白(P-gp)表达水平。阿霉素对瞬时转染及稳定转染的BT325耐药性进行分析。结果成功构建了逆转录病毒si RNA质粒载体,经过瞬时转染BT325细胞生长状态良好,48h表达绿色荧光最强。加入嘌呤霉素筛选后,在第8天出现单细胞克隆。免疫细胞化学染色证实瞬时转染与稳定转染BT325细胞P-gp的表达下降。细胞的转染效率为70%～80%。BT325细胞经过RNA干扰,细胞对MDR1耐药性明显下降,IC_(50)降低,细胞的耐药因子(RF)有所升高。结论siMDR1基因瞬时转染和稳定转染都可以抑制P-gp蛋白的表达,其可以作为基因治疗的重要手段。     

反义肽核酸逆转人神经母细胞瘤多药耐药性的实验研究

目的 探讨反义肽核酸(PNA)的细胞转染方法及对体外培养的神经母细胞瘤多药耐药性(MDR)的逆转作用。方法 以人MDR-1基因mRNA为靶点设计合成两反义PNA序列，利用PNA-DNA杂交，阳离子脂质体介导转染神经母细胞瘤耐药细胞株SK-N-SH。应用流式细胞术、RT-PCR、MTT等方法分别检测反义PNA的转染效率、转染前后细胞P-糖蛋白(P-gp)、MDR-1基因mRNA的表达以及对化疗药物的敏感性。结果 荧光标记的反义PNA转染肿瘤细胞后，细胞平均荧光强度显著增强，且呈浓度依赖性。两反义PNA均使SK-N-SH细胞P-gp表达明显降低，阿霉素和长春新碱对细胞的半数抑制浓度值明显下降，MDR-1 mRNA表达轻度降低。而PNA1转染对照组C6／adr细胞后，上述变化不明显。结论 PNA-DNA杂交阳离子脂质体转染法可有效增加细胞对PNA的摄取．特异序列的反义PNA可有效逆转神经母细胞瘤的MDR特性。     

马桑内酯点燃效应癫癎动物模型海马区星形胶质细胞的形态学研究

采用马桑内酯（coriarialactone，CL）肌注造成大鼠化学点燃效应癫动物模型并经光镜、电镜、突触素（synaptophysin）免疫组化方法对大鼠脑组织进行观察，发现，大鼠海马区星形胶质细胞有明显变性坏死。提示马桑内酯对星形胶质细胞有损伤性作用，星形胶质细胞的变性坏死可能在诱导癫发作中起重要作用。     

MicroRNA-182靶向抑制TLR4后减轻缺氧诱导的小胶质细胞炎症反应

目的研究microRNA-182（miR-182）靶向Toll样受体4（TLR4）对小胶质细胞炎症反应的影响。 方法利用转染试剂Lipofectamine 2000进行小胶质细胞的miR-182、小干扰TLR4 RNA（siTLR4）以及TLR4(ORF)过表达质粒的转染；通过氧糖剥夺处理，模拟缺血缺氧环境；通过荧光素酶基因检测报告检测TLR4是否是miR-182的直接结合靶点；通过Western blot、RT-PCR、ELISA检测mRNA以及蛋白的相对表达量。 结果miR-182与TLR4在缺氧条件下小胶质细胞中的表达具有相关性，TLR4是miR-182的直接作用靶点，miR-182可以抑制TLR4的表达，同时降低小胶质细胞的炎症因子（TNF-α、IL-6、IL-1β）的释放。 结论miR-182通过靶向抑制TLR4的表达来抑制缺氧诱导的小胶质细胞炎症反应。     

壳聚糖氧化铁纳米颗粒包裹MDR1 shRNA与对胶质瘤细胞转染的影响

目的探讨多药耐药基因短发卡RNA（MDRl shRNA）与壳聚糖氧化铁（Fe304）纳米颗粒对胶质瘤细胞系转染的影响。方法设计并合成针对MDRl的shRNA序列与pSIREN—RetroQ质粒载体连接,提取质粒,制备壳聚糖纳米颗粒并包裹制备的质粒,测定包封率及粒径分布。培养人类胶质母细胞瘤BT325共转染,测定转染效率。结果质粒pSIREN—RetroQ—RNAi经双酶切后测序验证,与实验设计的shRNA长度相符。壳聚糖一铁纳米粒子的粒径为100～300mm。分布较均匀．包裹质粒DNA包封率为97％-99％。壳聚糖Fe304纳米粒子包裹质粒经PI试剂转染BT325细胞,在共转染24h开始表达,荧光显微镜下呈绿色荧光,48h表达最强。转染效率为70％-80％（P〈0．05）。结论MDRlshRNA表达质粒与壳聚糖Fe3O4纳米粒子结合,可提高胶质瘤细胞系BT325转染效率,转染后细胞可以正常生长,可以为进一步的靶向基因检测及治疗提供有意义的思路。     

Diagnostic Difficulties and Treatment Implications

Summary: Differentiation between types of epileptic seizures has been aided in recent years by the introduction of intensive neurodiagnostic techniques and the development of increasingly detailed classification systems. Paradoxically, these developments have not simplified the task of matching the appropriate antiepileptic drug to a particular seizure type. It is reasonable to assume that anticonvulsant drugs will have different effects on different types of seizures, but faulty, circular reasoning can enter the picture if one also assumes that responses of seizures to different drugs signify different seizure types. There are several examples of differential diagnoses that can fall prey to this problem, including the diagnosis between partial seizures with secondary generalization and generalized tonic-clonic seizures, and the diagnosis between complex partial seizures and absence seizures with automatisms, among others. Considerations of etiology in future classification systems can further complicate the problem: should one then choose an anticonvulsant drug on the basis of individual seizure type or on the basis of the type of epilepsy? Ramifications of this issue extend even to the drug approval process. Official sanction is not given for use of a drug for a seizure type not included in the original efficacy studies, even if later scientific evidence shows that seizure type to be related to a type that is included. New trials must be undertaken. These problems arise from how we choose to classify seizures.     

Cognitive Dysfunction Associated with Antiepileptic Drug Therapy

Summary: Epilepsy is frequently associated with cognitive dysfunction. However, the reasons for this correlation are unclear. Possible influential factors include patient age; duration, frequency, etiology, and type of seizures; hereditary factors; psychosocial issues; and antiepileptic drug (AED) therapy. Whereas many of these factors are beyond the physician's control, AED therapy is one element that can be addressed in treatment decisions by recognizing the potential cognitive effects of particular AEDs. For example, phenobarbital impairs memory and concentration; phenytoin affects attention, problem solving ability, and performance of visuomotor tasks. In contrast, carbamazepine may affect concentration, while valproate would appear to have minimal effects on cognition. Moreover, cognitive effects of AEDs are amplified with coadministration of multiple anticonvulsants (polytherapy). A review of studies on the cognitive effects of monotherapy with AEDs, as opposed to those of polytherapy, provides evidence that drug-related cognitive dysfunction can be reversed if patients are switched to a simpler therapeutic regimen. Future research should be directed toward developing reliable measures for assessing and monitoring cognition, and understanding the particular cognitive side effects of each AED. Physicians also need to revise their opinions about which side effects are "tolerable" for epileptic patients.     

Carbamazepine Efficacy in Adults With Partial and Generalized Tonic-Clonic Seizures

Summary: Carbamazepine and phenytoin are drugs of choice in initial monotherapy for adult partial and secondarily generalized tonic-clonic seizures. These designations reflect the results of the Veterans Administration Epilepsy Cooperative Study Group of 1985. An earlier comparative study of carbamazepine and phenytoin by Ramsay and associates found both drugs equally effective in controlling new-onset seizures. Among the advantages of carbamazepine is that it causes relatively few cognitive and dysmorphic side effects. Its disadvantages are its unavailability in parenteral formulation and its metabolic autoinduction. The latter must be compensated for by planned dosage increases to maintain therapeutic plasma steady-state levels during the first 2 or 3 months of treatment. Carbamazepine is judged a drug of choice in the treatment of these secondarily generalized tonic-clonic seizures, and the drug of choice in children, adolescents, and women susceptible to the dysmorphic side effects associated with other anticonvulsant agents.     

Etiologic and Preventive Aspects of Epilepsy in the Child–Bridging the Gap Between Laboratory and Clinic

Summary: Four broad categories of basic phenomena are pertinent to developing ways to prevent epilepsy. These include mechanisms of epileptogenesis, ictal initiation and temporary entrainment by the seizure discharge of normally functioning brain, seizure propagation, and control mechanisms that function both to restrain the cascade of epileptic events culminating in a seizure and to arrest the epileptic event and restore the interictal state. In newborns and children, hypoxia-ischemia is a major factor leading to epileptogenesis, and several schemes are proposed to classify, quantify, and prevent hypoxic-ischemic encephalopathy. Control mechanisms must be better understood in order to develop prophylactic recommendations for epilepsy, and an experimental model of "kindling antagonism" may increase our understanding of these. Programs of prevention of seizures in children will evolve only if basic researchers and clinicians work productively together to develop an adequate understanding of factors important in epileptogenesis and antiepileptogenic control mechanisms.     

Epilepsy and anomalies of neuronal migration: MRI and clinical aspects

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.     

Predisposing and Causative Factors in Childhood Epilepsy

Summary: We review information from large studies of defined populations, examining the role of known factors and especially of prenatal and perinatal factors in contributing to nonfebrile seizure disorders of early childhood. We depend especially, but not exclusively, on the recently completed analyses from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the NCPP. About 4% of children in the NCPP who had at least one non-febrile nonsymptomatic seizure by the age of 7 years had a previous seizure during acute neurologic illness, such as meningitis or during the acute illness after trauma. Many such seizures should potentially be preventable. Of children with seizures, 10% had had a neonatal seizure and 13% had had a febrile seizure. Among the hundreds of prenatal and perinatal factors explored as predictors of childhood seizure disorders, the principal predictors identified were congenital malformations of the fetus, cerebral and noncerebral; family history of certain neurologic disorders; and neonatal seizures. In agreement with the British National Child Development Study, labor and delivery factors in the NCPP appeared to contribute very little to childhood seizure disorders. Maldevelopment, rather than damage at birth to an initially intact nervous system, appeared to be the more common mechanism. Most seizure disorders of early childhood remained unexplained by the large set of prenatal and perinatal characteristics examined.     

Anticonvulsant Drugs and Cognitive Function: A Review of the Literature

Summary: Alterations of cognitive function are separate from disturbances of behavior seen in association with epilepsy. The nature of the cognitive disability may to a certain extent depend on the seizure type. Partial seizures, mainly derived from a temporal lobe focus, impair memory tasks, while generalized seizures seem to have more effect on attentional abilities. A number of studies, reviewed in this paper, suggest that anticonvulsant drugs further impair cognitive function. Maximal impairments are seen in patients receiving polytherapy: rationalization of polytherapy improves cognitive abilities. Studies in children and adults have allowed differentiation of the effects of various commonly used antiepileptic agents. Maximal cognitive deficits are seen with. phenytoin, while phenobarbital and sodium valproate induce moderate disturbances, and carbamazepine seems relatively free from such toxicity. Further research is needed on the interrelationship between types of seizure disorders, types of anticonvulsant medications, and cognitive function.     

Treatment Considerations in Anticonvulsant Monotherapy

Summary: The long-standing practice of polypharmacy in treating epilepsy is giving way to use of monotherapy. Monotherapy can improve seizure control as well as reduce the risk of serious idiosyncratic reactions, dose-related side effects, and complex drug interactions. Monotherapy also offers improved compliance and cost-effectiveness. The basis of monotherapy is accurate diagnosis and assessment of the patient's seizure type(s), followed by selection of a single appropriate anticonvulsant drug. Many patients currently treated with multiple anticonvulsants can be successfully converted to monotherapy with a carefully monitored program in which troublesome and redundant drugs are gradually withdrawn from the therapeutic regimen.     

Classification of methods in transcranial Electrical Stimulation (tES) and evolving strategy from historical approaches to contemporary innovations

Transcranial Electrical Stimulation (tES) encompasses all methods of non-invasive current application to the brain used in research and clinical practice. We present the first comprehensive and technical review, explaining the evolution of tES in both terminology and dosage over the past 100 years of research to present day. Current transcranial Pulsed Current Stimulation (tPCS) approaches such as Cranial Electrotherapy Stimulation (CES) descended from Electrosleep (ES) through Cranial Electro-stimulation Therapy (CET), Transcerebral Electrotherapy (TCET), and NeuroElectric Therapy (NET) while others like Transcutaneous Cranial Electrical Stimulation (TCES) descended from Electroanesthesia (EA) through Limoge, and Interferential Stimulation. Prior to a contemporary resurgence in interest, variations of transcranial Direct Current Stimulation were explored intermittently, including Polarizing current, Galvanic Vestibular Stimulation (GVS), and Transcranial Micropolarization. The development of these approaches alongside Electroconvulsive Therapy (ECT) and pharmacological developments are considered. Both the roots and unique features of contemporary approaches such as transcranial Alternating Current Stimulation (tACS) and transcranial Random Noise Stimulation (tRNS) are discussed. Trends and incremental developments in electrode montage and waveform spanning decades are presented leading to the present day. Commercial devices, seminal conferences, and regulatory decisions are noted. We conclude with six rules on how increasing medical and technological sophistication may now be leveraged for broader success and adoption of tES.     

Effects of NMD A- and AMPA-Receptor Antagonists on Different Forms of Epileptiform Activity in Rat Temporal Cortex Slices

Summary: Lowering extracellular magnesium induces different patterns of epileptiform activity in rat hippocampus and entorhinal cortex. Short recurrent epileptiform discharges in the hippocampus are stable over time, whereas seizurelike events (SLEs) in the entorhinal cortex, the subiculum, and the neighboring neocortex develop into late recurrent discharges which are not blocked by clinically employed antiepileptic drugs. We tested the sensitivity of the different epileptiform discharge patterns to. /V-methyl-D-aspartate (NMDA)- and non-NMDA-receptor antagonists. As NMDA-receptor antagonist we used dextrorphan, ket-amine, and 2-aminophosphonovalerate (2APV); as α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)-receptor antagonist we employed the quinoxaline derivative glutamate 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). The findings show that the different patterns of epileptiform activity, including the late recurrent discharges, are sensitive to all NMDA-receptor antagonists. However, when dextrorphan was employed to suppress seizure-like events, later recurrent discharges did not develop during the remaining time course of the experiment. CNQX reversibly suppressed recurrent discharges in the hippocampus and SLEs in the entorhinal cortex. However, late recurrent discharges become insensitive to CNQX, even at a high concentration of 60 μM m. This finding suggests a prominent role for NMDA receptors in the generation of late recurrent discharges.