FK506对许旺细胞增殖及分泌功能的影响

背景：随着组织工程技术的发展,周围神经缺损的修复可望使用体外构建的人工神经修复解决。人工神经是以具有良好的生物相容性的可降解高分子聚合物为载体与有活性的种子细胞结合而成的复合体。雪旺细胞（Schwann Cell）最重要的种子细胞,这种细胞可以合成和分泌细胞外基质成分并和其他分子一起构成基板,形成有髓神经纤维的髓鞘和无髓神经纤维的内膜,而且雪旺细胞还分泌多种神经营养因子包括NGF（神经生长因子）等,对神经损伤后的轴突再生和功能恢复起着不可替代的作用。如果有雪旺细胞提供营养支持神经再生距离将增加,而无细胞的神经移植再生距离则较短。 FK506是继环孢素A之后发现的一种新的强效免疫抑制剂,其免疫抑制作用大约是环孢素A(CsA)的10倍。近年来一系列研究表明,FK506除较强免疫抑制作用外,更有促神经生长作用,如果FK506在人工神经中以适宜神经生长的浓度稳定而持久的释放,将对作为种子细胞的雪旺细胞起到保护、功能促进作用,为临床进行人工神经移植可首选FK506提供了一定的试验基础。 目的： 研究不同浓度的FK506对体外培养雪旺细胞增殖及分泌功能的影响。探讨FK506在组织工程化人工神经中应用的可能性。 方法：取3～5天SD大鼠的双侧的坐骨、臂丛神经,剪碎至1mm3大小的组织块,双酶消化法进行分离培养,低浓度胰酶快速消化传代进一步纯化雪旺细胞,用光镜进行形态学观察、S-100蛋白进行鉴定。将纯化的雪旺细胞分四组,一组设为对照,另三组分别加含终浓度为10-6mol/L、10-7 mol /L 、10-8mol/L FK506的DMEM培养液培养。原代细胞计数,观察雪旺细胞增殖情况;传代细胞MTT法检测不同时间点的OD值并绘制生长曲线,用ELISA法检测FK506促雪旺细胞分泌神经生长因子（NGF）的含量。动态观察不同浓度 FK506作用下雪旺细胞生长、活性及分泌功能状态。 结果：通过上述方法分离培养获得了增殖迅速的原代雪旺细胞,经S-100蛋白鉴定为雪旺细胞,经传代进一步纯化后各组雪旺细胞纯度均可以提高到90%以上。各组传代雪旺细胞培养3～5天后,细胞增殖明显。第1～3天,FK506组雪旺细胞的细胞活性与对照组相比,并无显著性差异。3天以后, FK506组的雪旺细胞生长明显优于空白对照组,差异有统计学意义(P＜0.05)。ELISA法检测结果显示FK506可明显促进雪旺细胞分泌NGF,而且随着时间的延长而逐渐增高,第4～8天时分泌量维持较高的水平,其中第6天时分泌量最高。而10-8mol/L组最为理想。 结论：采用出生3～5d的幼年鼠,坐骨神经及臂丛神经切取相对容易, 纤维结缔组织成分较少,培养获得雪旺细胞贴壁良好,增殖速度快,易于培养观察,可以满足神经组织工程研究的需要。FK506可以促进雪旺细胞增殖和NGF分泌的作用,这种作用在较低浓度（10-8mol/L）时效果更明显。体外培养雪旺细胞,FK506对雪旺细胞数量、活性及分泌功能有促进作用,这种作用可能是促进损伤神经再生加快神经生长速度的关键。     

FK506对脑外伤后中枢神经系统的保护及对学习记忆的影响

FK506作为全新的大环内酯类免疫抑制剂,不仅在肝肾等移植方面显示出其特有的优势,近年来发现其在缺血性脑血管疾病、神经系统退行性病变、脑外伤后神经保护及学习和记忆过程中具有重要的作用,而其对脑外伤后神经保护和促神经再生作用以及对学习和记忆的影响越来越引起人们的重视。     

不同免疫抑制剂对全血细胞MCP-1分泌的影响

目的：研究不同免疫抑制剂对全血细胞分泌单核细胞趋化蛋白-1（MCP-1）的影响。方法：健康志愿者全血与不同免疫抑制剂作用6小时后用佛波酯（PMA）联合离子霉素（IONO）刺激6小时,比较不同免疫抑制剂组MCP-1的水平。结果：高浓度,中浓度的地塞米松（DEX）及环孢素A（CsA）都能有效抑制MCP-1的分泌,而他克莫司（FK506）和麦考酚酸（MPA）不能有效抑制细胞因子的分泌。结论：DEX和CsA可有效抑制MCP-1的分泌,而FK506和MPA对MCP-1的分泌没有影响。     

FK506 (Tacrolimus)治疗激素依赖性重症肌无力的研究进展

重症肌无力是一种由T细胞依赖的、抗体介导的自身免疫性疾病。FK506是一种大环内脂类的代谢物,具有选择性抑制辅助性T细胞活动的特性。此文就FK506抑制T细胞的作用机制、药代动力学机制、在实验性自身免疫性重症肌无力中的研究情况、临床治疗方面的证据以及不良反应进行了综述。     

新型免疫抑制剂FTY720在器官移植及眼科中的应用

FTY720是冬虫夏草提取物ISP-I经过修饰合成的新型免疫抑制剂，不同于环孢素A、FK506等其他免疫抑制剂，具有独特的作用机制和很强的免疫抑制活性。文章从FTY720的免疫抑制机制入手，以FTY720诱导淋巴细胞凋亡和调节外周成熟淋巴细胞游走的免疫抑制机制为基础，并探讨FTY720的药理作用，证实了FTY720在器官移植动物模型中、免疫性疾病模型中、肿瘤疾病模型中、缺血再灌疾病模型中起着重要的作用，但FTY720在眼科的应用还处于基础阶段。     

抑制P-糖蛋白可加强FK506对缺血性脑损伤的保护作用

目的 探讨多药耐药蛋白(P糖蛋白,P-glycoprotein,P-gp)对FK506透过血脑屏障进入脑内浓度及其脑保护作用的影响.方法 用腔内线栓法制造小鼠脑缺血再灌注动物模型(MCAO);用甲酚紫染色法显示脑梗死区;用Western blot方法观察P-gp的表达;用ELISA法检测FK506浓度;用TUNEL法观察凋亡细胞.结果 MCAO 30 min再灌注3 h纹状体P-gp的表达开始显著升高,持续至24 h,MCAO 90 min组P-gp的表达升高幅度更大.脑缺血前后,P-gp抑制剂tariquidar(TQD)对血中FK506浓度的影响差异无统计学意义;使用TQD后,缺血侧大脑半球FK506含量显著升高.单独使用FK506时,只有较大剂量(5 mg/kg)才有抗细胞凋亡作用.单独使用TQD无抗细胞凋亡和减少脑梗死体积的作用,但当TQD与FK506合用时,FK506较低剂量(1 mg/kg)即可发挥抗细胞凋亡作用,使脑梗死体积从(113.5±11.1)mm3显著降低至(70.6±10.2)mm3(P＜0.01).结论 TQD抑制P-gp活性,增加FK506进入脑内的浓度,降低FK506脑保护作用的阈值(从5 mg/kg降低至1 mg/kg),从而加强FK506的神经保护作用.     

新免疫抑制剂FK-506抑制异种间脑移植排斥反应的效果

报道新免疫抑制剂FK-506(FK)抑制异种间脑移植排斥反应的实验研究效果.采用镜下摘除14日龄SD大白鼠黑质细胞在内的腹侧中脑组织,作为固形组织移植于生后8周龄的C_3H/He小白鼠右侧脑室,移植后连日皮下注射FK或生理盐水.将宿主分为3组:A组给予FK10.0mg/kg/d(n=5);B组给予FK1.0mg/Kg/d(n=5);C组(对照组)投予生理盐水0.1ml/day(n=5).3组均于移植14日后用4%多聚甲醇灌流固定,取脑,浸润固定后脱水冰冻,切成16～20μm的薄片,进行苏木精—曙红及Nissl染     

CYP3A5基因多态性指导他克莫司治疗重症肌无力的初步探讨

目的 比较他克莫司(FK506)治疗FK506不同代谢型重症肌无力(MG)患者的疗效、有效血药浓度、有效剂量及安全性的差异,并初步探讨CYP3A5基因多态性在指导MG个体化治疗中的作用.方法 收集MG患者32例,行CYP3A5*3 A6986G等位基因多态性检测,AA型及AG型归为快代谢型组,GG型为慢代谢型组.均给予FK506 0.5～1 mg/d口服,逐渐加量,每天记录患者绝对评分,当与治疗前相比绝对评分减少大于50％时,为治疗达标,记录当时的剂量、总服药天数及血药浓度.结果 达标时快代谢组的平均血药浓度/剂量(C/D)明显低于慢代谢组(P＜0.01),当时口服的FK506剂量/体重也明显大于慢代谢组(P＜0.01),达标时间也明显长于慢代谢组(P＜0.05),治疗期间共出现3例(9.4％)轻度不良反应.结论 FK506治疗不同CYP3A5*3基因型MG患者的起效时间、有效剂量、有效血药浓度均不同;CYP3A5基因多态性检查在FK506个体化治疗MG中具有一定指导意义.     

他可莫司治疗重症肌无力的研究进展

重症肌无力(myasthenia gravis,MG)是一种主要由乙酰胆碱受体抗体(acetylcholine receptor antibody,AChR-Ab)介导、细胞免疫依赖和补体参与的神经肌肉接头处的自身免疫性疾病.机体对自身AChR免疫应答异常是其发病本质,T细胞的异常激活是MG自身免疫反应发生的基础.他可莫司(tacrolimus,FK506)是一种新型免疫调节剂,可通过抑制神经钙调磷酸酶活性,进而抑制T细胞激活和各种细胞因子的产生而治疗MG,现就其目前研究进展报道如下.     

表皮生长因子受体抑制剂在中枢神经系统损伤中的应用

<正>表皮生长因子(EGF)受体(EGFR)自被发现以来,经过几十年的研究,其结构和功能已被较为全面的了解。目前临床常见的EGFR抑制剂(如西妥西单抗、易瑞沙等)主要被作为抗癌药物使用。但在2005年美国科学家Koprivica等[1]发现小分子EGFR抑制剂可以促进视神经损伤后节细胞轴突再生以后,EGFR抑制剂被逐步纳入到CNS损伤后的研究中,其有望成为一种治疗神经损伤的新药物。     

Neuroimaging in epilepsy in tropics

Epilepsy is a major public health problem in many tropical countries. Also, some of the tropical diseases are major contributors to the higher prevalence of epilepsy in these countries. The etiologic factors responsible for epilepsy in these countries are quite different from those in the developed world. This article discusses the etiologic factors and neuroimaging of epilepsy in light of the conditions in these tropical countries.     

癫痫与抑郁关系的研究进展

抑郁是癫痫患者中常见的精神障碍,严重地影响了患者的生活质量。传统的观点认为癫痫患者因为存在着诸多社会学问题易出现抑郁倾向,癫痫和抑郁是单向的联系,但大量的研究已经证明癫痫和抑郁之间存在双向的联系,一种异常状态的存在可能易转化为另一种异常状态的发展。癫痫和抑郁存在着共同的发病机制。本文主要就癫痫和抑郁的双向联系以及抗抑郁药物在癫痫患者中的应用进行阐述。     

Sudanophilic lipid accumulation in astrocytes in periventricular leukomalacia in monkeys

Summary Sudanophilic lipid accumulation is a characteristic feature of periventricular leukomalacia (PVL) of infants. At least two types of lipid-containing cells have been identified, one being the macrophage, the other the pre-myelin glial cell. A third type of lipid-containing cell has been seen in two monkeys with spontaneous PVL. Electron microscopically this cell appears to be an astrocyte. This probably represents a reaction of the astrocyte to hypoxia and may be the equivalent of the hypertrophic astrocytes found in human infants.Supported in part by NIH grant HDO 8633 and the Regional Primate Research Center Grant RR-00166     

Increase in cathepsin D activity in rat brain in aging

Cathepsin D-like activity in homogenates of five brain areas of 3-month-old and 24-month-old Fischer 344 rats was measured. With hemoglobin as substrate at pH 3.2, more than 90% of the activity was inhibited by pepstatin. In each area studied, activity was more than twice as high in the old rat brain: 140-160% higher in the cortex, cerebellum, pons-medulla, and striatum and 90-100% higher in the hippocampus and spinal cord. The greatly increased metabolic capacity in the absence of an increase in protein turnover may have a role in age-related pathological degeneration in the brain.     

Gender in Voice Perception in Autism

Deficits in the perception of social stimuli may contribute to the characteristic impairments in social interaction in high functioning autism (HFA). Although the cortical processing of voice is abnormal in HFA, it is unclear whether this gives rise to impairments in the perception of voice gender. About 20 children with HFA and 20 matched controls were presented with voice fragments that were parametrically morphed in gender. No differences were found in the perception of gender between the two groups of participants, but response times differed significantly. The results suggest that the perception of voice gender is not impaired in HFA, which is consistent with behavioral findings of an unimpaired voice-based identification of age and identity by individuals with autism. The differences in response times suggest that individuals with HFA use different perceptual approaches from those used by typically developing individuals.     

Increase in noradrenaline-synthesizing enzyme activity in medulla oblongata in Parkinson's disease

Summary Dopamine beta hydroxylase (DBH), the noradrenaline-synthesizing enzyme, and phenylethanolamine-N-methyltransferase (PNMT), the adrenaline-synthesizing enzyme, were assayed in 18 areas of brain stem in eight cases of parkinsonian syndromes and of four age- and postmortem delay-matched controls. Dissection was performed by the punch technique and enzyme activities assayed by radiometric methods. No significant change was found for PNMT activity. DBH activity was significantly increased in the A2-C2 area of the medulla oblongata (including the nucleus tractus solitarius) in the cases of Parkinson's disease.The A2-C2 area is known to be implicated in the control of blood pressure in rats. These findings are discussed in relation to orthostatic hypotension and the influence ofl-dopa therapy.Supported by grants from INSERM ATP 657897, ATP 8179113, CRL 79-1-356-6, DGRST (80 E 0882), FRMF, and Sandoz-France France     

Changes in parasympathetic system in medulla oblongata in male pigs in the course of tachycardia-induced cardiomyopathy

Background

Autonomic imbalance constituting a fundamental feature of heart failure (HF) has been assessed mainly at the periphery. Changes in the functioning of autonomic centers in the brain remain unclear. We investigated the molecular elements of parasympathetic system, i.e. α7 nicotinic acetylcholine receptor (α7nAChR) and enzymes metabolizing acetylcholine (acetylcholinesterase, AChE, choline acetyltransferase, ChAT) in medulla oblongata (MO) of male pigs with chronic tachycardia-induced cardiomyopathy.

Methods

The mRNA levels of AChE, ChAT, α7nAChR and X-box binding protein 1 (spliced form, XBP1s) in MO were analyzed using qPCR, AChE and ChAT activities using spectrophotometry, proteasome activity using fluorometry, and the protein level of α7nAChR using Western blotting.

Results

The development of systolic HF was accompanied by an increase in circulating catecholamines, a decrease in the AChE and α7nAChR mRNA in MO, an increase in AChE activity (all p < 0.05), and no change in either the mRNA or activity of ChAT. Both circulating catecholamine levels and AChE activity were inversely related to systolic function of left myocardial ventricle (p < 0.05). The level of α7nAChR protein in MO and its cytoplasmatic fraction were higher in pigs with moderate and severe HF as compared to the other animals (p < 0.01). There was no difference in proteasome activity in MO between diseased and healthy animals, whereas the XBP1s mRNA decreased during HF progression (p < 0.05).

Conclusions

Molecular elements of parasympathetic system are changed within the medulla oblongata during the progression of systolic non-ischemic heart failure in male pigs, indicating a functional link between MO and heart in HF.     

Issues in evaluation of cognition in the elderly in developing countries

Background:

Developing regions of the world host the majority of elderly subjects who are at risk for dementia. Reliable epidemiological data from these countries is invaluable in tackling this global problem. Scarcity of such data in literature is largely attributable to problems that are unique to developing communities worldwide.

Objective:

To classify and describe the problems that interfere with the collection of reliable epidemiological data on cognitive impairment in the elderly in developing communities, and to suggest practical solutions for some of them.

Methods:

Inferring from the experiences of a large, ongoing, population-based study on the cognitive impairments in the elderly in South India and from the review of literature.

Conclusion:

A fatalistic attitude regarding aging in the communities, significant heterogeneity in educational abilities and activities of daily living, high illiteracy among rural subjects, and lack of an organized health care system and updated demographic figures are some of the major factors that contribute to technical, namely, methodology-related problems and practical, namely, subject-related problems in such epidemiological studies.     

Suicide in the elderly in Austria

In most countries men and women have the highest suicide rates in age groups over 60 years. We investigated suicide rates for the elderly in Austria, a country with one of the highest suicide rates in the world, for the period 1980–1991, using data from the Federal Statistical Division. Suicide rates remained stable over the last decade at a very high level. The mean rate for men was 85.2, for women 28.6/100 000. In men and women rates rise with age. The mean rate of men rises from 51.2 (60–64 years) to 117.3/100 000 (over 85 years); in women there is an increase from 21.4 (60–64 years) to 32.8/100 000 (over 85 years). We did not confirm findings in other countries, where suicide rates have increased in recent years.     

Characteristics of nociceptors in the periodontium--an in vitro study in rats

Recent studies have indicated that nociceptors can be classified into various types according to their physiological properties. These studies have clarified that the frequency distribution of various nociceptor types is different among body sites and animal species. In the present study, we investigated the physiological properties of rat's periodontal nociceptors in an in vitro jaw-nerve preparation. Responses were recorded from functional single filaments in the inferior alveolar nerve. To determine the nociceptor type, calibrated von Frey filaments, heat, and bradykinin (BK) stimuli were used. We found five subtypes of nociceptors in the periodontal ligaments of the lower incisor: Adelta-high threshold mechanonociceptors (Adelta-HTM, n=28), Adelta-mechanoheat nociceptors (Adelta-MH, n=6), Adelta-polymodal nociceptors (Adelta-POLY, n=26), C-high threshold mechanonociceptors (C-HTM, n=3) and C-polymodal nociceptors (C-POLY, n=4). Most nociceptors were Adelta-innervated, while only a small number of C-innervated nociceptors were found. The present results suggest that periodontal nociceptors transmit mainly fast pain, and may thus play a role in rapid detection of injure-related stimuli during mastication.