还原型谷胱甘肽对左旋多巴毒性拮抗作用的实验研究

目的 :观察还原型谷胱甘肽 (GSH)对左旋多巴 (L dopa)毒性的拮抗作用。方法 :将实验动物分为 4组 (每组 8只 ) :治疗组 ,阴性对照组 ,阳性对照组 ,正常鼠组。比较给药前后的行为学变化 ,给药后测定各组大鼠黑质区GSH Px、MDA、ROS及线粒体呼吸链酶复合体Ⅰ水平。结果 :L dopa能加重黑质区氧化应激损伤 ,降低呼吸链酶复合体Ⅰ活性 ,GSH与其合用可部分拮抗上述作用。结论 :GSH能部分拮抗L dopa的毒性作用 ,对PD模型大鼠具有一定的细胞保护作用     

不同剂量左旋多巴对帕金森病大鼠行为学影响实验研究

目的　观察不同剂量左旋多巴 (L - dopa)治疗帕金森病 (PD)的效果 ,探讨 L - dopa治疗帕金森病的合理方法。方法　通过 6- OHDA脑立体定向注射术建立大鼠 PD模型 ,采用行为学、TUNEL、原位杂交的方法观察左旋多巴小、中、大 3种不同剂量 [10 mg/(kg· d)、5 0 mg/(kg· d)、10 0 mg/(kg· d) ]、不同的作用时间 (1d、3 d、5 d、7d)对 PD大鼠黑质细胞的毒性作用 ,并观察治疗后 7天各项指标的变化。结果　与对照组比较 ,小剂量组大鼠旋转圈数随 L- dopa使用计量和时间增加而减少 ,中、大剂量组相反 ,旋转启动时间随 L- dopa使用剂量和时间增加而加速 ,最高转速及持续时间则相反。结论　我们应尽可能小剂量、间隔使用 L - dopa治疗 PD。     

还原型谷胱甘肽保护性治疗帕金森病的机制研究

目的观察还原型谷胱甘肽(GSH)对帕金森病(PD)大鼠模型的异常行为、黑质抗氧化系统、线粒体呼吸链功能及细胞形态学的影响。方法应用6-羟基多巴胺立体定向注射制作PD大鼠模型。将24只大鼠随机分为3组(每组8只):模型组、GSH组、假手术组,分别给予相应处理,共45d,给药前后均进行行为学测试,给药后测定各组大鼠黑质区谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)、活性氧(ROS)及线粒体呼吸链酶复合体水平,并行免疫组化检测。结果(1)GSH对大鼠旋转行为无明显影响(P>0.05)。(2)GSH能减轻黑质区氧化应激损伤。(3)GSH能增强黑质呼吸链酶复合体I活性。(4)免疫组化发现GSH组TH-IR神经元数量较模型组明显增多。结论GSH能减轻PD模型大鼠黑质区氧化应激损伤,并对线粒体呼吸链及细胞形态具有一定保护作用。     

不同剂量左旋多巴对帕金森病大鼠行为学影响

目的观察不同剂量左旋多巴治疗帕金森病（PD）的效果,并进一步探讨合理使用左旋多巴治疗PD的剂量。方法采用6-OHDA脑立体定向注射术建立大鼠PD模型,采用行为学观察法观察3种不同剂量左旋多巴[按体重10、50、100mg/（kg.d）]作用不同时间（1、3、5、7d）对PD大鼠黑质细胞毒性作用后的行为学变化以及停止左旋多巴治疗后7d各项指标的变化。结果与对照组比较,小剂量组大鼠旋转圈数随左旋多巴使用剂量和时间增加而减少,中、大剂量组大鼠旋转圈数随左旋多巴使用剂量和时间增加而增加;各组大鼠旋转启动时间随左旋多巴使用剂量和时间增加而减少,最高转速及持续时间则随使用剂量增加而增加。结论应尽可能以小剂量、间隔使用左旋多巴治疗PD。     

左旋多巴对体外培养大鼠纹状体的神经毒性及其保护方法的研究

目的 研究左旋多巴（Ｌ－ｄｏｐａ）的神经毒性及其神经保护方法。方法 用胎盼兰染色法检测Ｌ－ｄｏｐａ和抗氧化剂还原型谷胱甘肽（ＧＳＨ）、ＮＭＤＡ受体拮抗剂ＭＫ８０１对体外培养大鼠纹状体的神经元活力的影响。结果 Ｌ－ｄｏｐａ使大鼠纹状体神经元活力明显下降（Ｐ〈０．０１）,ＧＳＨ和ＭＫ８０１可明显减轻Ｌ－ｄｏｐａ引起的纹状体神经元活力下降（Ｐ〈０．０１）。结论 Ｌ－ｄｏｐａ可能通过氧化应激和兴奋ＮＭＤＡ受体两个途径发挥其神经毒性,抗氧化剂或ＮＭＤＡ受体拮抗剂与Ｌ－ｄｏｐａ合用可能减轻Ｌ－ｄｏｐａ的神经毒性。     

慢性左旋多巴治疗对帕金森病大鼠行为及基底节Fos表达的影响

目的:研究帕金森病大鼠左旋多巴诱导异动症模型的行为学特征及其基底节区神经元活性的变化.方法:帕金森病大鼠给予左旋多巴治疗28 d,观察其行为学,并用免疫组织化学方法观察纹状体、苍白球区Fos表达情况.结果:慢性左旋多巴治疗后,帕金森病大鼠出现异常不自主运动,包括刻板运动和增加的对侧旋转行为.急性左旋多巴治疗帕金森病大鼠损毁侧尾壳核和苍白球区Fos表达均增加,慢性左旋多巴治疗与急性治疗组比较损毁侧尾壳核区Fos明显减少,而苍白球区表达增加.结论:慢性间断性左旋多巴治疗诱导帕金森病大鼠异常不自主运动是帕金森病患者左旋多巴诱导异动症的啮齿类动物模型,纹状体苍白球神经元活性增强可能参与其发生机制.     

PSD-95在长期左旋多巴对帕金森病模型大鼠效应中的作用

目的 探讨突触后致密物(PSD-95)在长期左旋多巴对帕金森病(PD)模型大鼠效应中的作用.方法 SD大鼠(60只)右侧前脑内侧束(MFB)立体定向注射6羟基多巴胺(6-OHDA)制作PD模型,另取8只大鼠注入溶剂作为正常对照组.32只大鼠造模成功,按随机数字表法分为PD组、左旋多巴+生理盐水组、左旋多巴+PSD-95反义寡核苷酸组、左旋多巴+TE组,每组8只.PD组大鼠予以腹腔注射0.2%维生素C水;后3组大鼠腹腔注射左旋多巴和苄丝肼建立PD运动并发症模型,持续22 d,在第23～25天分别给予腹腔注射生理盐水、纹状体注射PSD-95反义寡核苷酸和等容积TE缓冲液,于第25天记录各组大鼠旋转反应时间及剂峰旋转圈数的变化,应用RT-PCR、Western blotting分别检测纹状体部位PSD-95 mRNA、PSD-95蛋白的改变.结果 长期左旋多巴注射处理后第25天,与左旋多巴+生理盐水组和左旋多巴+TE组比较,左旋多巴+PSD-95反义寡核苷酸组大鼠旋转反应时间延长,剂峰旋转次数降低,差异有统计学意义(P＜0.05).RT-PCR和Western blotting检测结果显示,与正常对照组比较,PD组大鼠损伤侧纹状体部位PSD-95 mRNA和蛋白表达减少,差异有统计学意义(P＜0.05);与PD组比较,左旋多巴+生理盐水组大鼠损伤侧纹状体PSD-95mRNA、PSD-95蛋白的表达量升高,差异均有统计学意义(P＜0.05);与左旋多巴+生理盐水组比较,左旋多巴+PSD-95反义寡核苷酸组PSD-95蛋白的表达量降低,差异有统计学意义(P＜0.05).结论 长期左旋多巴治疗PD产生的运动并发症可能与纹状体区PSD-95的改变有关.     

左旋多巴在帕金森病治疗中的合理应用

帕金森病（Parkinson disease，PD）是一种常见的中老年神经变性疾病。据统计，65岁以上老年人群患病率为2％左旋多巴的出现是帕金森病治疗进程中的一个里程碑。到目前为止，左旋多巴仍是治疗帕金森病最有效的药物。然而，临床研究发现，长期应用左旋多巴可导致药物相关的药效减退、运动障碍、症状波动甚至精神障碍等问题，使得左旋多巴的治疗地位存在一定的争议和挑战。本文就国内外关于左旋多巴的用法、时机选择及运动并发症等方面作一概述。     

左旋多巴实验在帕金森病鉴别诊断中的意义

目的　帕金森病与帕金森综合症的药物鉴别诊断。　　方法　用美多巴实验来鉴别帕金森病人和帕金森综合症病人。　　结果　服美多巴 375mg后 ,原发性帕金森病组改善程度 ( 4 5%以上 )明显高于血管性或脑变性性帕金森综合症组 ( 1 9% ) ,而且副作用少。　　结论　左旋多巴实验对帕金森病有诊断意义。     

侧脑室微量注射左旋多巴治疗大鼠帕金森病

目的观察经侧脑室注射左旋多巴对帕金森病（PD）大鼠的影响。方法应用“羟基多巴胺立体定向脑内注射制备偏侧损毁的PD大鼠模型，并用阿扑吗啡（APO）皮下注射诱发大鼠向健侧旋转。将24只PD大鼠随机分为4组（n=6），经侧脑室注入生理盐水组为对照组，余3组分别经侧脑室注射浓度为0．1μg／μl、1μg／μl和5μg／μl的左旋多巴1μl，4μl／d，连续1周；观察在注射后不同时间大鼠旋转行为以及中脑黑质多巴胺能神经元数量的变化。结果经侧脑室注射1μg/μl和5μg/μl的左旋多巴后。与对照组相比，PD大鼠向健侧的旋转圈数明显减少（P〈0．01），左旋多巴效果在2h左右达到高峰，且中脑黑质多巴胺能神经元的数量也明显增多（P〈0．01）。结论经侧脑室注射适当剂量的左旋多巴可有效地改善PD大鼠的旋转行为，并增加中脑黑质多巴胺能神经元数量。     

Should levodopa dose be reduced when switched to stalevo?

The addition of entacapone to levodopa-carbidopa (LC) or the switch from LC to a tablet containing levodopa–carbidopa–entacapone (LCE) improves the wearing-off phenomenon, increases the 'on' time and decreases the 'off' time, but the appearance or exacerbation of dyskinesias is the more frequent side-effect. Thus, a reduction of the total levodopa dosage would be recommended. However, this could result in a lack of efficacy against the wearing-off. We report on the results of a clinical trial conducted to determine the best way in terms of efficacy, tolerability and safety of switching from LC to LCE in patients with Parkinson's disease (PD) and end of dose wearing-off. 39 patients with PD and wearing-off without or with mild dyskinesias were randomly assigned to either a group receiving the same LC dosage or to a group in which the total LC amount was reduced by 15–25%. Four weeks after the change, both groups showed an increase in daily 'on' time and a reduction in the daily time spent in 'off'. Two patients in each group experienced an increase in basal dyskinesias. No differences in clinical assessment between groups were found. Tolerance was excellent. This study suggests that switching from LC to LCE in patients with mild-to-moderate wearing-off can be done safely with or without reducing the total LD amount, but in the clinical setting it would be more practical to keep the dosage of LC unchanged unless severe dyskinesias are present.     

Longitudinal study of the motor response to levodopa in Parkinson's disease.

In this prospective study of 34 patients with Parkinson's disease, measurements of the short duration levodopa motor response have been performed in defined off states at 3 yearly intervals over a mean period of 11.4 years from the point of commencement of levodopa treatment. Twenty-two patients were still available for study; 10 had died and 2 were lost to follow-up. The levodopa motor response amplitude increases over the first 5 years of treatment, and thereafter, on and off scores worsen in parallel with conservation of the response. Patients who developed motor fluctuations within the first 5 years of treatment had, on average, a stronger response to levodopa with significantly better on phase motor function (P = 0.003). Although the proportion of "midline" motor disability (affecting gait, balance, and cranial motor function) increases with time, these deficits do not actually become unresponsive to levodopa. Patients who developed dementia had a significantly more rapid decline in motor function. The latest graph of serial scores for the whole cohort shows an upward curving or exponential increase in motor disability after the first decade of treatment. Applying a notional untreated disability line to this graph--an estimate of the disability that would have accrued if drugs had never been given--we suggest that the long-duration response to levodopa eventually runs down with disease progression.     

Systematic review of levodopa dose equivalency reporting in Parkinson's disease

Interpretation of clinical trials comparing different drug regimens for Parkinson's disease (PD) is complicated by the different dose intensities used: higher doses of levodopa and, possibly, other drugs produce better symptomatic control but more late complications. To address this problem, conversion factors have been calculated for antiparkinsonian drugs that yield a total daily levodopa equivalent dose (LED). LED estimates vary, so we undertook a systematic review of studies reporting LEDs to provide standardized formulae. Electronic database and hand searching of references identified 56 primary reports of LED estimates. Data were extracted and the mean and modal LEDs calculated. This yielded a standardized LED for each drug, providing a useful tool to express dose intensity of different antiparkinsonian drug regimens on a single scale. Using these conversion formulae to report LEDs would improve the consistency of reporting and assist the interpretation of clinical trials comparing different PD medications. © 2010 Movement Disorder Society     

Longitudinal study of levodopa in Parkinson's disease: Effects of the advanced disease phase

Thirty‐four patients have been studied from the time of initiation of pharmacological treatment in a long‐term prospective study of levodopa effects and disease progression in Parkinson's disease. Objective motor scoring of the response to levodopa in defined off states was performed every 3 years. The mean time from the initiation of levodopa treatment to the most recent measurements was 18.2 years. Of 8 patients who are still alive, only 3 had none of the features of the advanced disease phase (dementia, hallucinations, frequent falling). Off‐phase motor function worsened at a yearly rate of 1.9% of the maximum disability score, although the plots of the serial scores showed that the magnitude of the levodopa response is well preserved. There was little difference in the rate of progression between patients with tremor‐dominant and non‐tremor‐dominant motor subtypes. Those who developed dementia had more rapid deterioration of motor scores, with significantly worse off‐phase (P = .008) and on‐phase (P = .03) motor function. A graph of serial scores of patients who have died, aligned for time of death, showed an upward curving trend of motor disability in the last 5 years of the disease course. Its advanced phase may reveal that Parkinson's disease has an exponential pattern of progression. © 2013 Movement Disorder Society     

Psychotic complications of long-term levodopa treatment of Parkinson''s disease

The prevalence of psychotic complications of levodopa treatment was assessed in 198 Parkinson patients. The symptoms were seen in 44 (22.2%). Those who developed complications were significantly older at disease onset (63.3 +/- 9.2 vs 57.6 +/- 11.6). The observed psychiatric symptoms were classified into two categories: simple, including incidents of confusion alone or hallucinations with preserved insight, and complex, including delusions or chronic confusion without preserved insight. Patients with complex symptoms were significantly younger at the onset of the disease, and the duration of the disease prior to these psychiatric symptoms was longer than in the group of patients with simple symptomatology. Patients with complex symptoms were more susceptible to another central side-effect of the treatment: dyskinesias, than those with simple.     

Unmasking levodopa resistance in Parkinson's disease

Some motor and nonmotor features associated with Parkinson's disease (PD) do not seem to respond well to levodopa (or other forms of dopaminergic medication) or appear to become resistant to levodopa treatment with disease progression and longer disease duration. In this narrative review, we elaborate on this issue of levodopa resistance in PD. First, we discuss the possibility of pseudoresistance, which refers to dopamine‐sensitive symptoms or signs that falsely appear to be (or have become) resistant to levodopa, when in fact other mechanisms are at play, resulting in suboptimal dopaminergic efficacy. Examples include interindividual differences in pharmacodynamics and pharmacokinetics and underdosing because of dose‐limiting side effects or because of levodopa phobia. Moreover, pseudoresistance can emerge as not all features of PD respond adequately to the same dosage of levodopa. Second, we address that for several motor features (eg, freezing of gait or tremor) and several nonmotor features (eg, specific cognitive functions), the response to levodopa is fairly complex, with a combination of levodopa‐responsive, levodopa‐resistant, and even levodopa‐induced characteristics. A possible explanation relates to the mixed presence of underlying dopaminergic and nondopaminergic brain lesions. We suggest that clinicians take these possibilities into account before concluding that symptoms or signs of PD are totally levodopa resistant. © 2016 International Parkinson and Movement Disorder Society     

Effects of levodopa on finger and orofacial movements in Parkinson''s disease

1. 1. The objective of this study is to compare the efficacy of levodopa on finger and orofacial movements in Parkinson's disease. The sensitivity of the orofacial and finger systems to levodopa would suggest the involvement of dopaminergic lesions.

2. 2. The production of isometric force was estimated in both conditions, without and with levodopa, in 14 patients with idiopathic Parkinson's disease (mean duration of symptoms: 9 ± 3 years).

3. 3. Forces generated by the upper and lower lips, tongue, right and left forefingers in the presence of visual feedback were measured by means of force transducers.

4. 4. The target force levels used in the present study included 0.25, 0.5, 1 and 2 newtons corresponding to fine forces presumably involved in speech production. Moreover, motor disability of patients was assessed in each condition, using the motor examination of the Unified Parkinson's disease rating scale and a hand-tapping test.

5. 5. Fourteen control subjects also participated in this study.

6. 6. The beneficial effect of levodopa on finger movements was observed as indicated by an improvement in motor scores and production of forces. In contrast, the production of orofacial forces was either not improved, or aggravated by levodopa.

7. 7. These results suggest that cerebral non dopaminergic lesions participate to the impairments of parkinsonian speech.

     

Myopathy as a first symptom of Huntington's disease in a Marathon runner.

A semi professional marathon runner at risk for Huntington's disease (HD) (43 CAG repeats) developed signs of a slowly progressive myopathy with exercise-induced muscle fatigue, pain, elevated creatine kinase level, and worsening of his running performance many years before first signs of chorea were detected. Muscle biopsy displayed a mild myopathy with mitochondrial pathology including a complex IV deficiency and analysis of the patient's fibroblast culture demonstrated deficits in mitochondrial function. Challenging skeletal muscle by excessive training might have disclosed myopathy in HD even years before the appearance of other neurological symptoms.     

Review: Central nervous system involvement in mitochondrial disease

Mitochondrial respiratory chain defects are an important cause of inherited disorders affecting approximately 1 in 5000 people in the UK population. Collectively these disorders are termed ‘mitochondrial diseases’ and they result from either mitochondrial DNA mutations or defects in nuclear DNA. Although they are frequently multisystem disorders, neurological deficits are particularly common, wide‐ranging and disabling for patients. This review details the manifold neurological impairments associated with mitochondrial disease, and describes the efforts to understand how they arise and progressively worsen in patients with mitochondrial disease. We describe advances in our understanding of disease pathogenesis through detailed neuropathological studies and how this has spurred the development of cellular and animal models of disease. We underscore the importance of continued clinical, molecular genetic, neuropathological and animal model studies to fully characterize mitochondrial diseases and understand mechanisms of neurodegeneration. These studies are instrumental for the next phase of mitochondrial research that has a particular emphasis on finding novel ways to treat mitochondrial disease to improve patient care and quality of life.