槲皮素对大鼠脑胶质瘤抑瘤作用的体内实验研究

目的观察槲皮素及顺铂对大鼠脑胶质瘤生长的抑制作用,初步探讨其作用机制。方法将30只颅内接种C6胶质瘤细胞的SD大鼠随机分为3组:分别给予顺铂、槲皮素及对照治疗7 d,观察各组肿瘤生长情况,于接种后17 d处死各组大鼠,收集肿瘤标本进行肿瘤大小、HE染色及电镜观察,并通过免疫组化检测肿瘤组织增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)的表达。结果顺铂组[(66.2±5.9)mm3]、槲皮素组[(59.6±5.4)mm3]肿瘤体积低于对照组[(101.1±9.6)mm3]槲皮素组优于顺铂组(t=10.61,P<0.01),槲皮素组、顺铂组肿瘤抑制率分别为41.3%、34.8%。光镜观察槲皮素组、顺铂组肿瘤细胞密度降低,电镜显示有细胞凋亡。PCNA免疫组化结果显示槲皮素组(42.2%±5.1%)、顺铂组(50.0%±6.7%)肿瘤PCNA表达减少,与对照组(79.6%±8.6%)相比,具有统计学差异(F=416.12,P<0.01),两两比较,槲皮素组治疗效果优于顺铂组(q=55.25,P<0.01)。结论槲皮素和顺铂均可显著抑制大鼠颅内C6胶质瘤细胞生长,其机制可能与诱导肿瘤细胞凋亡和抑制肿瘤细胞增殖有关。     

^125IUdR对大鼠C6脑胶质瘤细胞AgNOR和PCNA表达的影响

目的探讨5-[125I]-2'-脱氧尿苷(125IUdR)对大鼠C6胶质瘤细胞中嗜银核仁组织原区蛋白(AgNOR蛋白)和增殖细胞核抗原(PCNA)表达的影响。方法体外培养C6胶质瘤细胞,建立C6胶质瘤Wistar大鼠模型,合成125IUdR和127IUdR后于肿瘤原位局部注射,5日后处死动物取标本分别行AgNOR染色和PCNA免疫组织化学染色,计算AgNOR颗粒数目、面积和PCNA标记指数。结果125IUdR治疗组C6胶质瘤细胞的AgNOR颗粒计数和面积、PCNA标记指数分别为(1.70±0.42)个/细胞,(4.32±1.38)μm2/细胞,(36.87±14.51)%;对照组分别为(2.50±0.37)个/细胞,(7.01±1.97)μm2/细胞,(52.24±10.86)%,两组相比均相差显著(P<0.05)。结论125IUdR可掺入肿瘤细胞DNA的合成中,选择性的杀伤S期的肿瘤细胞,显著的抑制C6胶质瘤细胞中AgNOR和PCNA的表达,从而抑制胶质瘤细胞的增殖。     

冷冻治疗对大鼠C6脑胶质瘤细胞凋亡和p21表达的影响

目的研究冷冻治疗对大鼠C6脑胶质瘤细胞凋亡及其调控机制的影响。方法建立C6大鼠脑胶质瘤动物模型,于冷冻治疗后第15天留取标本,以末端标记法(TUNEL)、流式细胞仪(FCM)检测肿瘤细胞凋亡,以免疫组化技术检测p21蛋白的表达。结果冷冻可诱导C6大鼠脑胶质瘤细胞凋亡,上调p21的表达,二者呈显著正相关(P<0.01)。FCM分析显示G1峰前出现典型的亚二倍体峰。结论诱导细胞凋亡可能是冷冻杀伤脑胶质瘤细胞的另一重要机制;p21基因可能参与了这种细胞凋亡的调控。     

声动力化学疗法对大鼠颅内胶质瘤的杀伤作用

目的探讨声动力化学疗法(SDT)对大鼠颅内胶质瘤的杀伤效应。方法制作大鼠颅内C6胶质瘤实验模型,将大鼠随机分为声动力治疗(SDT)组、超声(US)组、血啉甲醚(HMME)组、对照组,治疗后行颅内胶质瘤MRI影像学检查及组织光镜、电镜观察,并记录4组大鼠生存期。结果 MRI显示:治疗3 d、7 d后,SDT组肿瘤体积分别为(47.05±1.96)mm3、(13.02±1.15)mm3,较其他3组明显减小(均P<0.01)。光镜显示:SDT组肿瘤组织坏死于治疗后24 h达到高峰。电镜显示:治疗后24 h,SDT组见大量坏死细胞,部分细胞呈凋亡表现;US组少量细胞呈凋亡表现。SDT组生存期为52.25 d,较其他3组明显延长(均P<0.01)。结论 SDT对大鼠颅内C6胶质瘤有明显抑制效应。     

反义AKT2 cDNA治疗C6胶质瘤的体内外实验研究

目的研究反义AKT2(antisense AKT2，AS—AKT2)cDNA对鼠脑胶质瘤细胞系C6的生长抑制作用。方法将AS—AKT2 cDNA构建体转染鼠脑胶质瘤细胞系C6，原位杂交和蛋白印迹鉴定后，应用PCNA阳性率和MTT法检测细胞增殖能力，TUNEL法计算凋亡指数。应用立体定向技术将C6细胞和转染反义AKT2 cDNA的C6细胞种植到SD大鼠的右侧尾状核作为对照组和转染组；并对颅内已经形成C6胶质瘤的大鼠进行脂质体包裹的AS—AKT2 cDNA和空载体治疗；MRI动态监测大鼠颅内肿瘤生长情况，并检测标本AKT2和PCNA表达以及细胞的凋亡情况。结果转染AS—AKT2 cDNA后C6细胞AKT2表达显著抑制，增殖减慢，凋亡指数增加。反义治疗组和转染组大鼠生存时间明显延长；转染组和治疗组肿瘤标本AKT2表达下降或消失，PCNA阳性率降低，可见大量凋亡细胞，而对照组和空载组标本几乎没有凋亡细胞。结论体内外实验证明AS—AKT2 cDNA可以抑制肿瘤细胞增殖、诱导凋亡，AKT2可作为基因治疗胶质瘤的重要优选靶的。     

脑胶质瘤细胞中HIF-1α表达及其与细胞凋亡、增殖关系

目的探讨缺氧诱导因子-1α(HIF-1α)在人脑胶质瘤中的表达及其与肿瘤细胞增殖、细胞凋亡和肿瘤恶性程度的关系。方法采用免疫组化法检测60例脑胶质瘤HIF-1α、增殖细胞核抗原(PCNA)的表达,用TUNEL法检测肿瘤细胞凋亡情况,对结果进行综合分析。结果HIF-1α总阳性表达率为73.3%,其中强表达19例(31.7%),中度表达14例(23.3%),弱表达11例(18.3%),不表达16例(26.7%);胶质瘤Ⅰ~Ⅱ级、Ⅲ~Ⅳ级HIF-1α的阳性率分别为50.0%、86.8%,组间有统计学差异(P<0.01)。脑胶质瘤标本PCNA及细胞凋亡均阳性,胶质瘤Ⅰ~Ⅱ级、Ⅲ~Ⅳ级PCNA阳性细胞数分别为54.9±8.2、121.6±15.6,凋亡细胞阳性数分别为85.4±10.4、52.1±7.6,比较均有显著性差异(P<0.01)。HIF-1α表达与肿瘤细胞的PCNA阳性数呈正相关(P<0.01),与肿瘤细胞的凋亡数无明显关系(P>0.05)。结论脑胶质瘤细胞HIF-1α表达与肿瘤的恶性程度有一定相关性;HIF-1α表达水平与肿瘤细胞增殖呈正相关,而与肿瘤细胞的凋亡无关。     

伽玛刀治疗大鼠脑胶质瘤前后VEGF、PCNA表达及细胞凋亡研究

目的:通过应用伽玛刀对C6大鼠脑胶质瘤的治疗,检测治疗前后反映血管生成情况的血管内皮生长因子(VEGF)、反映细胞增殖情况的增殖细胞核抗原(PCNA)等的动态变化规律以及它们与凋亡的关系,探讨这些治疗效应在放射外科中的意义。方法:应用免疫组化及细胞凋亡方法进行统计学分析。结果:治疗后VEGF和PCNA表达降低,凋亡率明显高于对照组。结论:伽玛刀对于大鼠脑胶质瘤有明显的治疗作用。     

白细胞介素24对大鼠脑胶质瘤细胞Survivin表达的影响

目的探讨白细胞介素24(IL-24)基因对荷瘤大鼠脑胶质瘤细胞Survivin表达的影响。方法 48只SD大鼠随机分为实验组和对照组,每组24只,分别接种IL-24/C6细胞(转染IL-24基因的C6鼠脑胶质瘤细胞)和C6鼠脑胶质瘤细胞。接种21 d后,采用RT-PCR、Western blot和免疫组化方法检测两组大鼠脑肿瘤组织中Survivin mRNA和蛋白的表达,采用流式细胞学检测肿瘤细胞凋亡率。结果 RT-PCR检测显示:实验组大鼠脑肿瘤组织中Survivin mRNA表达水平明显低于对照组(P<0.01)。Western blot及免疫组化法检测显示:实验组大鼠脑肿瘤组织中Survivin的蛋白水平明显低于对照组(P<0.01)。流式细胞学结果显示:实验组细胞凋亡率显著高于对照组(P<0.01)。结论 IL-24可抑制大鼠胶质瘤中Survivin mRNA和蛋白的表达,促进细胞凋亡,抑制肿瘤生长。     

氩氦冷冻治疗后的荷C6胶质瘤大鼠的磁共振成像和病理研究

目的 探讨荷C6胶质瘤大鼠经氩氦刀治疗后的影像学和病理学的变化. 方法 将51只Wistar大鼠背部皮下植入体外扩增的C6胶质瘤细胞,制作荷C6胶质瘤的动物模型,模型制作成功后按照随机数字表法分为假手术组(暴露肿瘤后只插入冷冻刀头不启动氩氦冷冻系统,n=18),外科手术切除组(将肿瘤完整切除,不进行冷冻操作,n=15)和氩氦冷冻组(暴露肿瘤后启动氩氦冷冻系统,n=18).观察各组大鼠治疗前后MRI影像变化,应用Tunel检测细胞凋亡情况.结果 外科手术成功切除胶质瘤.氩氦冷冻组MRI显示T1、W1信号较术前增强,T2WI信号较术前减低假手术组治疗后MRI无明显变化.氩氦冷冻组肿瘤组织Tunel染色可见大量凋亡细胞,外科手术切除组及假手术组可见少量散在的凋亡细胞.结论 经氩氦刀治疗胶质瘤MRI提示肿瘤细胞变性坏死,病理学提示可以介导细胞凋亡,有望成为脑胶质瘤的一种有效的辅助治疗手段.     

大鼠C6脑胶质瘤生长的动态观察和MR灌注成像可行性研究

目的研究大鼠C6脑胶质瘤的生长规律,初步探讨其MR灌注成像研究的可行性。方法立体定向技术将C6细胞接种在13只SD大鼠的右侧尾状核建立模型。MR增强扫描动态观察第一组8只大鼠的肿瘤生长状况。在瘤龄第17 d,对笫二组5只荷瘤大鼠进行磁共振灌注成像(MR PWI)检查,根据时间-信号曲线计算为相对脑血容量(rCBV)和最大信号下降百分比(SRRmax)值。结果第一组大鼠生存期为23.5±3.93 d。肿瘤最大径随瘤龄增长呈线性增大,体积呈指数规律增大,濒死前肿瘤的最大径为9.19±236 mm,体积为515.66±303.33 mm3。第二组大鼠皆成功进行了MR PWI检查,肿瘤组织和正常脑组织rCBV分别为179.04±46.02和87.04±23.00,SRRmax分别为39.91％±6.80％和24.11％±6.36％,肿瘤组织和正常脑组织有显著性差异(P<0.01)。结论大鼠C6脑胶质瘤肿瘤生长有规律性,可用作MR PWI研究。     

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.     

Hepatic Considerations in the Use of Antiepileptic Drugs

Summary: Virtually all of the major antiepileptic drugs (AEDs) can cause hepatotoxicity, although fatal hepatic reactions are rare. The mechanisms, incidences, and risk profiles for such reactions differ from drug to drug. With carbamazepine and phenytoin, hepatotoxicity may be due to drug hypersensitivity. Although the profiles of patients at risk have not been well-defined for these two antiepileptic drugs, it would appear from reports in the literature that older adolescents and adults are at higher risk than children of developing serious or fatal hepatotoxicity. Once hepatotoxicity develops, mortality rates are 10–38% with phenytoin and 25% for carbamazepine. The risk profile for valproate fatal hepatotoxicity has been more clearly defined. Those at primary risk of fatal hepatic dysfunction are children under the age of 2 years who are receiving multiple anticonvulsants and also have significant medical problems in addition to severe epilepsy. The risk is considerably lower for patients over the age of 2 years on valproate monotherapy. In contrast to the risk profile with other AEDs, adults receiving valproate as monotherapy have the lowest risk of hepatotoxicity. Fatal hepatic dysfunction coincident with valproate may be the result of aberrant drug metabolism. Concomitant use of AEDs that induce microsomal P450 enzymes (e.g., phenytoin and phenobarbital) may enhance the production of a toxic metabolite, and hence the greater risk of hepatotoxicity with polypharmacy.     

Vascular Malformations and Epilepsy: Clinical Considerations and Basic Mechanisms

Summary: Vascular malformations (VMs) are associated with epilepsy. The natural history of the various VMs, clinical presentation, and tendency to provoke epilepsy determine treatment strategies. Investigations have probed the mechanisms of epileptogenesis associated with these lesions. Electrophysiologic changes are associated with epileptogenic cortex adjacent to VMs. Putative pathophysiologic mechanisms of epileptogenesis include neuronal cell loss, glial proliferation and abnormal glial physiology, altered neurotransmitter levels, free radical formation, and aberrant second messenger physiology.     

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.     

Carbamazepine Efficacy and Utilization in Children

Summary: Carbamazepine is effective for preventing partial and generalized tonic-clonic seizures in children. Although absence epilepsies are more common in children than adults, an estimated 80% of children with epilepsy have seizure types or epilepsies that are potentially responsive to carbamazepine. The differential diagnosis of ictal staring is an especially important issue in children because absence and atypical absence seizures are more prevalent in children than adults. Age-related pharmacokinetic differences and drug interactions are major considerations in children. On average, children have higher clearance rates of carbamazepine, shorter half-lives, and higher ratios of carbamazepine-10, 11-epoxide to carbamazepine than adults. In addition, children with severe epilepsy are more likely to require multiple-drug therapy, which can lead to complex drug interactions. When carbamazepine is administered along with valproate, drug protein binding interactions can cause intermittent side effects.     

Neonatal Seizures: Problems in Diagnosis and Classification

Summary: The clinical identification of neonatal seizures is critical for the recognition of brain dysfunction; however, diagnosis is often difficult because of the poorly organized and varied nature of these behaviors. Current classification systems are limited in their ability to communicate motor, autonomic, and electroencephalo-graphic features of seizures precisely and to provide a basis for uniform effective diagnosis, therapy, and determination of prognosis. Recent investigations of neonates, utilizing bedside electroencephalographic/polygraphic/ video monitoring techniques, have provided the basis for improved diagnosis and classification of seizures in the newborn. These studies have demonstrated that not all clinical phenomena currently considered to be seizures require electrocortical epileptiform activity for their initiation or elaboration. In addition, the specific clinical character of the phenomena considered to be seizures, the clinical state of the infant, and the character of the EEG indicate the probable pathophysiological mechanisms involved and suggest probable etiologies, prognosis, and therapy. Similarities between animal models that demonstrate reflex physiology and neonates with motor automatisms and tonic posturing suggest that these clinical behaviors may not be epileptic in origin but, rather, primitive movements of progression and posture mediated by brainstem mechanisms. Although not all clinical behaviors currently considered to be neonatal seizures may have similar pathophysiological mechanisms, they are clinically significant because they all indicate brain dysfunction.     

Valproate Monotherapy in the Management of Generalized and Partial Seizures

Summary: For decades, therapeutic tradition has promoted the concept of polypharmacy in the management of epilepsy. In recent years, however, studies have shown that, for most patients, monotherapy can provide comparable or better seizure control than administration of multiple anticonvulsants, while diminishing the potential for adverse reactions, drug interactions, and poor compliance. Valproate is an important monotherapeutic agent that is highly effective in the control of idiopathic primary and secondarily generalized epilepsies, and partial seizures that do not generalize. Comparative studies have found that valproate is at least as effective as phenytoin and carbamazepine in the treatment of generalized and partial seizures. Given the similar efficacy, other factors such as pharmacokinetics and side effects may therefore determine anticonvulsant selection for monotherapy.     

Un nouveau cadre conceptuel de travail pour la psychiatrie

In an attempt to place psychiatric thinking and the training of future psychiatrists more centrally into the context of modern biology, the author outlines the beginnings of a new intellectual framework for psychiatry that derives from current biological thinking about the relationship of mind to brain. The purpose of this framework is twofold. First, it is designed to emphasize that the professional requirements for future psychiatrists will demand a greater knowledge of the structure and functioning of the brain than is currently available in most training programs. Second, it is designed to illustrate that the unique domain which psychiatry occupies within academic medicine, the analysis of the interaction between social and biological determinants of behavior, can best be studied by also having a full understanding of the biological components of behavior.     

Special Pharmacokinetic Considerations in Children

Summary: Pediatric patients have greater degrees of pharmacokinetic variability and unpredictability than adults. This variability results from the effects of pharmacogenetics, age and growth, prior and current comedication, and disease. Newborns with seizures have the least predictable dosage requirements, and their needs change as drug-eliminating mechanisms mature in the neonatal period. Infants have the highest relative capacities to eliminate antiepileptics of any age group and require the largest relative doses. In addition to age-related trends, children demonstrate the same drug-specific, pharmacokinetic phenomena that adults do, including nonlinear phenytoin elimination, nonlinear valproate binding, and autoinduction of carbamazepine. Intercurrent illness and drug interactions further modify the age-related pharmacokinetic patterns in children and make dosage requirements even more unpredictable. Recent studies have shown that febrile illness can affect drug elimination, sometimes decreasing drug levels by 50% or more. Intermittent treatment with benzodiazepines administered either orally or rectally can be an important adjunct and help minimize this type of problem for children with marginally controlled epilepsy. Intermittent benzodiazepines are also helpful for children who have febrile seizures and who need only occasional antiepileptic protection.