BDNF基因重组逆转录病毒表达载体pLEGFP-BDNF的构建与鉴定

目的构建脑源性神经营养因子(BDNF)基因重组逆转录病毒表达载体。方法根据 BDNF基因已知序列,设计合成一对引物并导入HindⅢ和BamH Ⅰ酶切位点;从大鼠海马组织提取总 RNA,逆转录聚合酶链反应(RT-PCR)获得编码BDNF的基因片段,与克隆载体pMD 18-T Simple连接构建pMDT-BDNF质粒;经HindⅢ、BamHⅠ双酶切,获得BDNF基因片断再克隆至逆转录病毒载体 pLEGFP-N1中构建重组质粒pLEGFP-BDNF。结果限制性内切酶酶切分析和PCR法鉴定表明为正确重组子,测序结果证实与已知序列吻合。结论构建的重组逆转录病毒表达载体 pLEGFP-BDNF含有序列正确的大鼠BDNF基因,可以作为今后治疗老年性痴呆动物模型转基因实验的基因来源。     

大鼠黏结蛋白聚糖1基因重组腺病毒载体的构建及感染效率☆

背景：重组腺病毒质粒的构建方法主要有体外连接法和同源重组法。同源重组法有操作复杂、耗时长、效率低、纯化难的缺点。体外连接法又不可避免非特异性的基因重组及基因突变。 目的：应用改良体外连接法构建携带黏结蛋白聚糖1基因的重组腺病毒载体，测定其在心肌成纤维细胞中的感染效率。 设计、时间及地点：单一样本实验，于2007-08/2008-02在中山大学附属第二医院林百欣实验中心完成。 材料：穿梭载体pShuttle-CMV（含绿色荧光报告基因）和腺病毒骨架质粒pAdxsi购自诺赛基因组研究中心有限公司。 方法：核苷酸序列鉴定pCMV-Sport6.1-Sdc1质粒；用KpnⅠ + XhoⅠ从质粒pCMV-Sport6.1-Sdc1切出黏结蛋白聚糖1基因片段，亚克隆至pShuttle-CMV中，形成重组穿梭质粒。用I-CeuI + I-SceI双酶切出重组穿梭质粒中CMV-Sdc1片段，亚克隆至腺病毒基因组质粒中，得到重组腺病毒质粒。将重组腺病毒质粒转染293细胞包装获得重组腺病毒AdCMVSdc1，转化体外培养的心肌成纤维细胞。 主要观察指标：用DNA测序、酶切及聚合酶链反应法鉴定重组质粒和病毒，并测定重组腺病毒的滴度和感染效率。 结果：①核苷酸序列分析表明，pCMV-Sport6.1-Sdc1质粒正确携带大鼠黏结蛋白聚糖1 cDNA；黏结蛋白聚糖1基因被克隆于载体pShuttle-CMV上，以KpnⅠ + XhoⅠ双酶切可回收3 kb的克隆片段和5.1 kb的载体片段；重组腺病毒质粒用XhoⅠ酶切得到7个片段而空载体仅得到6个片段。②重组腺病毒质粒在293细胞中包装后产生的重组腺病毒对293细胞有致病作用；提取病毒DNA行聚合酶链反应鉴定可扩增出1.13 kb的特异性片段；用病毒上清多次重复感染293细胞扩增重组腺病毒后，病毒滴度检测达2.0×1011 PFU/mL。③用纯化浓缩后的重组腺病毒以感染复数为100感染心肌成纤维细胞，24 h后所有细胞均表达绿色荧光。 结论：成功构建了携带大鼠黏结蛋白聚糖1基因的重组腺病毒载体，经纯化浓缩后具有较高的滴度，能有效转染心肌成纤维细胞。     

保守性多巴胺能神经营养因子重组杆状病毒转移载体的构建及鉴定

目的 构建并鉴定小鼠保守性多巴胺能神经营养因子(mCDNF)重组杆状病毒转移载体pFastBacHTb-mCDNF. 方法 应用Trizol法提取小鼠组织总RNA,反转成cDNA,经PCR扩增得到带有预定酶切位点(BamH Ⅰ、Xho Ⅰ)的mCDNF基因全长(564 bp),回收片段并克隆至pGEM-T载体,测序验证PCR结果的准确性.将mCDNF定向克隆到pFastBacHTb载体,构建含有mCDNF基因的重组质粒pFastBacHTb-mCDNF,转化大肠杆菌DH5α感受态细胞,氨苄青霉素抗性筛选阳性克隆,摇菌抽取质粒进行测序和双酶切鉴定. 结果 RT-PCR扩增产物经琼脂糖凝胶电泳显示得到预定大小的目的 条带(564 bp),mCDNF的T-A克隆经蓝白斑抗性筛选获得阳性克隆,PCR及测序均提示pGEM-T-CDNF载体成功构建.重组质粒pGEM-T-mCDNF和pFastBacHTb载体进行BamH Ⅰ、Xho Ⅰ限制性内切酶酶切后再连接,得到pFastBacHTb-mCDNF重组质粒,并经PCR、酶切及测序验证无误. 结论 本实验成功构建了mCDNF重组杆状病毒转移载体pFastBacHTb-mCDNF,为该营养因子的进一步研究奠定了一定基础.     

单纯疱疹病毒Ⅰ型基因治疗载体的快速构建

背景：单纯疱疹病毒Ⅰ型载体因具有独特的优点目前被广泛应用,但其构建尚缺乏一种快速有效的方法。 目的：利用Cre/Loxp高效重组系统构建单纯疱疹病毒Ⅰ型载体。 方法：分离单纯疱疹病毒HSV-1,将含Cre重组酶的c66-SV40-cre质粒转染Vero细胞,构建一株带有Loxp位点的重组HSV-1框架载体HSVLoxp。构建穿梭载体pShuttle- SV40-Cre-Loxp-IRES及重组单纯疱疹病毒Ⅰ型载体HSV-GDNF,用HAT培养基筛选出阳性毒株后用GDNF引物做PCR鉴定,扩增培养后测定滴度。 结果与结论：成功构建pHV-TK-GFP质粒,并在Vero细胞内发生重组,分离出缺失了Us3基因的重组病毒HSVtk-Loxp-GFP01。成功构建HSV-1框架载体HSVLoxp及穿梭载体pShuttle- SV40-Cre-Loxp-IRES,成功获得GDNF基因,并将其转移到了HSV-1基因组上,成功构建了表达GDNF的单纯疱疹病毒HSV-1载体,测定其滴度约为2.25×106 IU/mL。     

抑制骨髓基质干细胞雌激素受体β基因表达的有效序列*☆

背景：雌激素受体β是否参与介导骨髓间充质干细胞的增殖与分化需进一步实验论证。 目的：以RNAi技术寻找和验证对大鼠骨髓基质干细胞雌激素受体β基因表达抑制的有效序列。 方法：根据GeneBank 数据库提供的SD大鼠雌激素受体β基因核苷酸序列,选择设计能转录小发卡结构RNA (Small hairpin RNAs,shRNA)的DNA 序列。再在两条互补碱基序列的5’端分别加上BamH Ⅰ(GATCC)和Hind Ⅲ (AGCTT)酶的酶切位点,最后形成两条互补的克隆入pSilencer 3.1-H1载体的发夹状siRNA模板序列,进行重组载体的碱基序列测定。 结果与结论：重组质粒碱基序列鉴定后,证实真核表达载构建正确。雌激素受体β特异性siRNA真核表达载体构建成功。     

重组大鼠质粒pEGFP-GDNF的构建及真核细胞转染

目的　构建携带大鼠胶质细胞源性神经营养因子(GDNF)基因的真核细胞表达载体,为应用GDNF进行如帕金森综合征之类的神经元退化性疾病的基因治疗打基础。方法　采用RT- PCR方法从大鼠胎脑组织总RNA中扩增出该基因的c DNA序列,并克隆到增强型绿色荧光蛋白(EGFP)报告基因的真核表达载体p EGFP- C1中,对重组质粒p EGFP- GDNF进一步鉴定。采用电转及阳离子脂质体将重组质粒p EGFP- GDNF转染至SH- SY5 Y细胞。结果　大鼠GDNF c DNA已正确地克隆到真核表达载体p EGFP- C1中,而构建成重组大鼠质粒p EGFP-GDNF。GDNF基因可稳定表达在细胞中。结论　真核细胞表达载体p EGFP- GDNF以及表达GDNF工程细胞SH-SY5 Y的成功构建,为进一步开展GDNF基因治疗PD等中枢神经系统疾病奠定了基础。     

构建人csp-B核基质结合区克隆及其介导的反转录载体

背景：核基质结合区是染色质被限制酶消化后仍附着在核基质上的DNA序列。大量实验表明，核基质结合区可以作为DNA复制的起始点或调控基因的转录，构建核基质结合区表达载体能提高外源基因表达水平，增强外源基因表达的稳定性及提高转化细胞稳定株的频率等。 目的：通过克隆人基因组不同的核基质结合区片段，构建核基质结合区介导的包含氯霉素乙酰转移酶(CAT)报告基因的反转录病毒载体pLXSN-MAR，以探索核基质结合区对基因表达的影响。 方法：开放性实验于2007-01/12在新乡医学院生物化学与分子生物学实验室及分子研究室完成。自行构建含氯霉素乙酰转移酶报告基因的质粒PLXSN-CAT载体。TaqDNA聚合酶、T4 DNA连接酶、DNA Marker、限制性内切酶BamHⅠ、凝胶纯化试剂盒、质粒提取试剂盒均购于大连 TaKaRa公司；引物由上海生工生物工程技术服务有限公司合成。以人基因组DNA为模板，采用聚合酶链反应扩增csp-B 核基质结合区序列，克隆入反转录载体PLXSN-CAT中，经限制性内切酶酶切及DNA序列分析鉴定目的基因。 结果与结论：聚合酶链反应扩增的特异性片段长度为931 bp，以此构建的重组质粒命名为PLXSN-CAT-MAR，经BamHⅠ酶切后显示5.9 kb和931 bp左右的两条片段，测序结果与Gen-bank中的人csp-B 核基质结合区(Genbank序列号M62716)序列一致，证明人核基质结合区片段已成功克隆到了反转录载体PLXSN-CAT中。提示成功构建了PLXSN-CAT-MAR反转录表达载体。     

人14-3-3β蛋白的原核表达、抗血清制备及真核表达载体的构建

目的 纯化原核表达的14-3-3β(YWHAB)重组蛋白并制备多抗血清,构建适用于哺乳动物细胞的真核表达载体.方法 将重组蛋白表达载体pET30a(+)/YWHAB转化大肠杆菌表达菌株BL21(DE3)感受态细胞,异丙基-β-D-硫代半乳糖苷(IPTG)诱导重组蛋白表达,镍-四齿螯合剂(Ni-NTA)亲和层析柱纯化重组蛋白;以纯化的重组蛋白为抗原免疫BALB/c小鼠,应用ELISA和Western blot方法分别检测抗血清的效价和特异性;应用PCR扩增添加BamH Ⅰ和EcoR Ⅰ酶切位点把YWHAB的ORF亚克隆至真核表达载体pEGFP-N1,添加BamH Ⅰ和Hind Ⅲ酶切位点把YWHAB的开放阅读框(ORF)亚克隆至真核表达载体pCDNA3.1(+),对重组载体进行酶切和PCR鉴定.结果 YwHAB重组蛋白以可溶性形式表达,分子量为32 000,与预期分子量一致;纯化后的重组蛋白纯度达90%以上,ELISA结果显示其抗血清的效价为1:50 000,Western blot结果表明抗血清的特异性较好;酶切和PCR鉴定结果表明真核表达载体pEGFP-N1/YWHAB和pCDNA3.1(+)YWHAB构建成功.结论 通过亲和层析纯化获得人14-3-3β重组蛋白,进而免疫BALB/c小鼠制备多抗血清,为进一步研究人14-3-3β的功能成功构建了其真核表达载体.     

构建携带重组人胰岛素基因慢病毒表达载体及其病毒包装

背景：腺病毒载体作为脂肪组织工程转基因载体,在应用中存在转导细胞免疫排斥及炎症反应等问题。应用慢病毒作为载体转染干细胞尤其是应用含胰岛素基因的慢病毒载体转染干细胞可避免腺病毒载体的诸多问题。 目的：实验拟构建含有人重组胰岛素(insulin)与增强型绿色荧光蛋白(enhanced green fluorescent protein, EGFP)基因慢病毒表达载体pLenti6.3-insulin-IRES-EGFP,并进行病毒颗粒包装。 方法：应用聚合酶链反应方法获得目的基因,在目的基因上、下游分别加上BamHⅠ,AscⅠ两个酶切位点,进行T载体克隆,转化入感受态DH5α细胞中,通过筛选获得重组质粒。用限制性内切酶酶切,将目的基因片段和pLenti6.3-IRES-EGFP载体连接,转化入感受态DH5α细胞中,通过筛选获得慢病毒表达载体pLenti6.3-insulin-IRES-EGFP,并进行测序。抽提慢病毒载体,转染293T细胞,包装病毒,测定病毒滴度。 结果与结论：通过聚合酶链反应获得长度为347 bp带有BamHⅠ和AscⅠ序列的目的基因。pMD18-T 载体和慢病毒表达载体pLenti6.3-IRES-EGFP连接,慢病毒表达载体pLenti6.3 -insulin-IRES-EGFP构建与预期相匹配,成功包装慢病毒颗粒。     

神经轴突运动蛋白Kif1a启动子基因全长序列报告基因载体构建

目的克隆Kif1a启动子区基因全长序列,构建并鉴定Kif1a启动子全长序列荧光素酶报告基因载体p GL3-Kif1a。方法以含Kif1a启动子基因全长序列的基因片段(2565 bp)的重组p GEM-T easy载体为模板,用含有酶切位点的特异性引物扩增出Kif1a启动子基因全长序列1853 bp,克隆至荧光素酶表达载体p GL3-basic,构建含正确目的基因的表达载体p GL3-Kif1a,行Sac I和Xho I酶切、PCR及测序鉴定;并以该质粒转染小鼠SCG细胞进行活性检测。结果酶切、PCR及序列测定表明,克隆获得的1853 bp与Gen Bank DNA序列数据库对比分析序列一致,插入方向正确;且p GL3-Kif1a启动子在小鼠SCG细胞中有明显转录活性。结论成功构建了Kif1a启动子基因全长序列荧光素酶报告基因载体,为下一步研究Kif1a启动子的活性分析、基因表达调控机制及其信号转导通路等研究奠定了基础。     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Dextromethorphan: Cellular Effects Reducing Neuronal Hyperactivity

Summary: Dextromethorphan is a dextrorotary morphinan without affinity for opioid receptors, commonly used as an antitussive medication. During the past 5 years, interest in the compound and its demethylated derivative, dextrorphan, has been revived because additional neuroprotective and an-tiepileptic properties were found in in vitro studies, animal experiments, and a few clinical cases. Both morphinans are able to inhibit N -methyl-D-aspartate (NMDA) receptor channels and voltage-operated calcium and sodium channels with different potencies. The inhibition of the NMDA receptor is believed to be the predominant mechanism of action responsible for the anticonvulsant and neuroprotective properties of the compounds.