生酮饮食对幼鼠戊四氮诱导痫性发作的影响及海马CA3区形态学观察

目的　探讨生酮饮食 (KD)对幼鼠戊四氮 (PTZ)诱导痫性发作阈值的影响及海马结构的病理改变。方法　通过尾静脉输注 PTZ,测定 KD饲料和普通饲料喂养两组 Wistar幼鼠的痫性发作阈值 ,并对其抽搐行为进行评分 ,同时对致痫后两组幼鼠海马 CA3区的病理学改变进行观察。结果　KD组幼鼠 PTZ诱导的痫性发作阈值明显高于对照组 (P <0 .0 1 ) ,但两组痫性发作的强度差异无显著性 (P >0 .0 5 )。 KD组幼鼠海马 CA3区正常锥体细胞计数较对照组明显增多 ,神经元损伤程度较轻。结论　KD可提高幼鼠 PTZ诱导的痫性发作阈值 ,但不影响发作强度 ;KD可减少痫性发作次数 ,对致痫幼鼠具有神经保护作用。     

脑网络在抑郁症中的应用研究进展

抑郁症的病因尚不明确,目前的研究显示抑郁症病人特定脑区神经病理改变.神经影像学研究表明"边缘-皮质-纹状体-苍白球-丘脑"[1]通路在抑郁症的病理生理机制中起着重要作用.一些功能影像学资料与抑郁症的核心临床特征相关研究一致,但由于抑郁症是一类异质性疾病,其临床表现形式多样,目前尚未找到相应的生物学标记,因此有很多神经影像学研究结果往往不一致,很难以某些脑区的异常结果来概括所有抑郁症的神经病理学发病机制,这使得传统的神经影像学研究遭遇瓶颈.近几年来,随着计算医学和神经影像技术的发展,为了突破这种研究孤立脑区的局限,学者们开始着手从网络水平上整体性探求抑郁症的发病机理.目前国内外有关这方面的研究正方兴未艾,本文就基于脑影像学的脑网络在抑郁症中的研究进展作一综述.     

神经内镜手术的疗效

随着神经内镜器械的不断完善,手术方法的不断改进和创新以及手术经验的逐渐积累,神经内镜在神经微创外科等领域的应用越来越成熟,应用范围也越来越广.神经内镜手术在欧美等发达国家开展得较早,研究得也比较多,我国起步则较晚,但发展较快,有部分市级医院也开始了这项技术,并取得许多有价值的成果.为让更多医疗工作者了解神经内镜手术的治疗效果,帮助更多患者获得神经内镜手术良好的疗效,现将神经内镜手术治疗的一些优势综述如下.     

神经胶质细胞的功能:摄取递质

本文研究神经胶质细胞参与在中枢神经系统内作力突触递质的某些物质的摄取问题。神经胶质细胞可能参与突触递质的灭活这个概念,从Koelle 1955年的研究得到了最初的支持,在他的研究中表明虽然特异性的乙酰胆碱酯酶是局限于神经元细胞内,但非特异性的胆碱酯酶却广泛地分布在神经胶质细胞中.虽然非特异性的酶在终止突触传递中多半是不重要的,但它可能在消除逸出突触间隙的乙酰胆碱方面起一定的作用。作者们研究了富有神经胶质     

胶质瘤起源细胞与分子病因研究

神经干细胞和胶质瘤干细胞的研究成功,对早有定论的胶质瘤起源细胞学说发出了挑战.在胶质瘤细胞中,为数不多的干细胞是生成肿瘤的细胞已经证实,但肿瘤干细胞是否起源于神经干细胞仅仅只是推测.两者间的分子关系是研究的切入点,推测调控分子就是胶质瘤发生的分子病因.     

APC基因与精神分裂症及其他相关神经精神疾病

虽然既往对抑癌基因APC (adenomatous polyposis coli)的研究多与结肠癌的发病机制有关,但近年来分子生物学的研究表明:它与中枢神经系统的功能维持、神经发育和突触形成有密切关系,可能是某些神经精神疾病,特别是精神分裂症的一个易感基因.     

电流感觉阈值测试在2型糖尿病小纤维神经病变的早期诊断价值

目的探讨电流感觉阈值测试(current perception threshold,CPT)在2型糖尿病小纤维神经病变中的早期诊断价值。方法选择临床确诊的2型糖尿病患者99例,应用肌电图仪常规法进行双侧正中神经、双侧腓浅神经感觉神经传导速度检测,应用感觉神经定量检测仪进行双正中神经、双腓浅神经CPT测定,电流刺激频率分别为2000Hz、250Hz、5Hz,比较CPT及SCV两种指标的异常率;依患者有、无自觉症状分为两组,依病程5年(45例)、5年≤病程10年(32例)及病程≥10年(22例)分为三组,分别比较双侧正中神经、双侧腓浅神经不同频率刺激CPT值及SCV。结果双正中神经、双腓浅神经CPT异常率明显高于SCV异常率(P0.05、P0.01)。与无症状组比较,有症状组患者左侧正中神经与双侧腓浅神经的SCV均明显减慢(均P0.05),双侧正中神经与双侧腓浅神经2000Hz刺激时CPT值均明显增高(均P0.05),250Hz和5Hz时CPT值两组间比较差异无统计学意义(均P0.05)。双正中神经、双腓浅神经的不同频率CPT阈值及SCV在不同病程组间差异均无统计学意义(均P0.05)。结论 CPT在糖尿病小纤维神经病变早期诊断中具有一定价值。联合神经传导速度测定可能提高糖尿病神经病变的诊断率。     

内质网应激在神经胶质瘤治疗中的研究进展

神经胶质瘤,简称胶质瘤,是发生于神经外胚层、起源于神经间质细胞的肿瘤.胶质细胞瘤是脑肿瘤中发病率最高的肿瘤,约占脑肿瘤总数的40.49％,且近年来仍呈上升趋势[11.至今,手术治疗仍然是临床治疗神经胶质瘤的主要方式,但由于胶质瘤的侵袭性生长以及其解剖位置的特殊性,使得神经胶质瘤难以做到被大范围彻底切除,从而导致胶质瘤的临床复发率仍较高.近年来如何控制手术后复发、寻找特异性药物治疗的靶点已成为该研究的热点领域.而内质网应激(ERS)促凋亡机制的发现,则为神经胶质瘤的治疗提供了新的方向.     

帕金森病情绪障碍

情绪障碍可以影响帕金森病患者的生活质量及疾病预后.神经心理学测验和神经影像学研究发现,帕金森病患者情绪障碍可能与中脑-边缘系统、中脑-皮质多巴胺能通路损害有关,但具体的病理学机制尚待进一步研究.本文拟就帕金森病患者情绪障碍的临床表现、可能的病理生理学机制、诊断及治疗进行探讨.     

儿童注意缺陷多动障碍听觉感知能力初探

儿童注意缺陷多动障碍(attention deficit hyperactivity disorder, ADHD)是儿童期最常见的神经精神疾病之一.近年来,ADHD儿童的认知功能成为了国内外学者的研究热点.但对于听觉信息加工的研究较少见.     

Response of cat skin mechanothermal nociceptors to cold stimulation

In the cat skin, the activity of 5 mechanothermal nociceptors has been studied to cold nociceptive stimuli. The frequency of discharge is very low (maximum of 2.0 Hz). The repetition of very cold stimulations decreased the discharge threshold of these receptors. After -5 degrees C stimulus, the mechanothermal nociceptors were completely inhibited during 3 to 7 minutes. These mechanothermal nociceptors should have an important function in cold pain.     

Peripheral nerve demyelination in multiple sclerosis

OBJECTIVE: To elucidate the frequency of peripheral nerve demyelination in multiple sclerosis (MS). There are a number of case reports describing MS patients associated with demyelinating neuropathy, but its frequency in a whole MS population is unknown. METHODS: Extensive nerve conduction studies were prospectively performed in 60 consecutive patients with relapsing-remitting MS. Multiple excitability measurements using threshold tracking were also performed in median motor axons and superficial radial sensory axons. RESULTS: Nerve conduction abnormalities suggestive of demyelination were found for 3 (5%) of the patients. Two of them developed clinically evident neuropathy, whereas the remaining one had only generalized areflexia in addition to MS symptoms/signs. In all the three, MS preceded demyelinating neuropathy by several years. Excitability testing showed that supernormality and threshold electrotonus at the tested sites (median motor axons at the wrist, and radial sensory axons at the mid-forearm) were similar in the normal and MS groups. CONCLUSIONS: MS patients do not generally have peripheral nerve demyelination, but approximately 5% of patients develop demyelinating neuropathy. The association could result from a common pathogenesis possibly due to epitope spreading during the long course of MS. SIGNIFICANCE: Association of chronic inflammatory demyelinating polyneuropathy with MS is not frequent, but needs to be recognized as a treatable condition.     

Steroid hormones affect limbic afterdischarge thresholds and kindling rates in adult female rats

Catamenial epileptics show particular vulnerability to seizures during menstruation and at the time of ovulation, when circulating estradiol (E(2))/progesterone (P(4)) ratios are high. The present study tested the hypothesis that alterations in neuronal excitability induced by E(2) and P(4) affect thresholds and the development of secondary generalization in kindled rats. METHODS: The effects of endogenous hormones secreted during the estrous cycle, and of exogenous exposure to E(2) and P(4) after ovariectomy (OVX), with and without adrenalectomy (ADX), were tested. Kindling electrodes were implanted in the basolateral amygdala or dorsal hippocampus in adult female rats. The anticonvulsive effects of P(4) on amygdala kindled seizures were also determined in intact subjects. RESULTS: In intact females, afterdischarge thresholds (ADTs) in the amygdala were significantly lower (306+/-48 microA; peak to peak) at mid-day proestrus, just prior to ovulation, when serum E(2) is elevated. ADTs were more than twofold higher (808+/-95 microA) during metestrus, coincident with peak ovarian P(4) secretion. In OVX females, amygdala thresholds were lowest with E(2) replacement and highest with P(4) replacement. Hippocampal ADT was unaffected by hormone replacement after OVX. The rates of both amygdala and hippocampal kindling were significantly accelerated by E(2) and slowed by P(4). E(2) replacement significantly increased serum corticosterone (CORT) levels. In ADX rats, CORT replacement increased kindling rates, synergizing with the effects of E(2). In fully kindled animals, P(4) administration suppressed motor seizures in approximately 60% of cases. CONCLUSIONS: E(2) lowers amygdala ADTs and facilitates kindling. This effect may involve both direct E(2) effects and indirect effects mediated via increased levels of circulating corticosterone. P(4) raises amygdala ADTs, slows kindling development and suppresses fully kindled seizures. Hence, P(4) may have potential therapeutic value for women with catamenial epilepsy.     

不同背景波脑电图大鼠戊四氮致痫域值的探讨

目的 通过脑电图定量分析及戊四氮(PTZ)致痫观察,探讨不同背景波脑电图大鼠PTZ的致痫域值.方法 健康成年大鼠30只,采用头皮和皮层电极两种方法进行脑电图定量分析比较；建立大鼠急性脑外伤模型,采用头皮电极分别描记急性脑外伤组和对照组大鼠脑电图,并对各波段进行定量分析；探讨PTZ最小致痫量.结果 大鼠皮层脑电图的波形基本上与头皮导联的波形相似,但波幅较大,二者各波段的相对功率值比较差异无统计学意义(P＞0.05)；大鼠脑损伤组定量脑电图慢波(δ、θ波段)较健康大鼠对照组显著增加,快波α波显著减少,α、β、θ波相对功率值比较差异有统计学意义(P＜0.05)；大鼠脑损伤组致痫所需最小PTZ量值较对照组值要小(P＜0.05).结论 脑电图应用于临床非精确定位时,头皮导联可代替皮层导联；脑外伤后大鼠脑电图定量分析δ、θ慢波波段相对功率值明显增加,α、β快波波段相对功率值下降,其中α波减少更为显著；脑外伤后大鼠PTZ致痫域值下降.     

Smell identification function in children with attention deficit hyperactivity disorder

Objective

Deficits in olfactory function are common features in neurodegenerative and neuropsychiatric disorders. Olfactory processing is related to dopamine metabolism and orbitofrontal cortex functioning, both known to be involved in the neurobiology of ADHD. Some investigations suggested alterations in olfactory processing (identification and detection threshold) in patients with ADHD. Despite increasing knowledge, controversy about this topic still exists regarding children with ADHD. This study was conducted to help elucidate some of this controversy.

Methods

50 participants (8-15 years, mean=10.70±1.77) with ADHD were compared to 50 controls. The two groups were well matched for age, gender and Mean School Scores (MSS). We assessed odor identification and threshold through a smell test composed of two tests of identification and detection threshold. Odor detection threshold was assessed with the odorant phenyl ethyl alcohol solved in propylene glycol using a single staircase method. Odor identification was assessed with chemical essences of five common odorants.

Results

The mean Sensory Identification Score for children with ADHD and the control groups were 3.76 (1.06) and 4.46 (0.76), respectively (p<0.001). The mean for Sensory Threshold Score for ADHD and control group was 6.4 (3.35) and 9.75 (2.16), respectively (p<0.001).

Conclusion

This study replicated altered olfactory performance in ADHD. Substantial olfactory deficits across the two domains of identification and detection threshold are observed in children with ADHD. These deficits do not seem to be a result of olfactory task difficulty and are not influenced by age, gender and MSS. Further studies are required to investigate whether olfactory function can be used as a biological marker for early diagnosis, treatment and prognosis of ADHD.     

Cheiro-oral-pedal syndrome due to brainstem hemorrhage

Cheiro-oral-pedal syndrome is characterized by specific sensory disturbance around the corner of the mouth, in the hand and in the foot on the same side. Lesions responsible for causing this syndrome vary. We report two cases of cheiro-oral-pedal syndrome due to midbrain and pontine hemorrhage, respectively. Pontine hemorrhage producing cheiro-oral-pedal syndrome has been reported in three cases, but this is the first case that midbrain hematoma exhibits this syndrome. Damage in the sensory pathway can cause cheiro-oral-pedal syndrome. Difference in the threshold may explain the specific sensory pattern in this syndrome. Cheiro-oral-pedal syndrome is caused by lacunar infarction in majority of the cases. However, it should be kept in mind that hematomas can cause cheiro-oral-pedal syndrome.     

Altered motor axonal excitability in patients with cervical spondylotic amyotrophy

Objective

To investigate the changes in motor axonal excitability properties in cervical spondylotic amyotrophy (CSA).

A Ketogenic Diet Increases the Resistance to Pentylenetetrazole-Induced Seizures in the Rat

Summary: Purpose: The purpose of this study was to test the hypothesis that a ketogenic diet would increase the resistance of rats to pentylenetetrazole (PTZ)-induced seizures and to understand the relation of ketonemia to seizure resistance.
Methods: A freely consumed, high-fat (ketogenic) diet was administered to male Sprague-Dawley rats for 5–10 weeks, while control animals were fed either rodent chow or a high-carbohydrate diet. Ketonemia was measured as plasma levels of β-hydroxybutyric acid (β-OHB). Seizures were induced by tail-vein infusion of pentylenetetrazole.
Results: The ketogenic diet produced a highly significant (p <0.01) increase in β-OHB levels within 5 days. Induction of seizures by PTZ 35 days after animals were placed on their respective diets showed that ketogenic animals had a significantly (p <0.01) increased threshold for seizure induction compared with those fed an isocaloric diet of either high-carbohydrate or normal rodent chow. Ketogenic animals did not exhibit increased seizure severity relative to controls, despite receiving consistently higher doses of PTZ.
Conclusions: The ketogenic diet resulted in an increased seizure threshold, confirming the hypothesis, and seizure threshold was found to be a direct function of the level of ketonemia.