正常和退变腰椎间盘蛋白质的双向电泳和质谱鉴定

背景：近年来对于退变腰椎间盘组织蛋白质成分改变的研究取得了很大进展,但是对于正常和退变腰椎间盘整体蛋白质成分改变的分离和差异鉴定却鲜见报道。 目的：建立正常和退变腰椎间盘蛋白质的双向电泳图谱,鉴定差异表达蛋白,探讨腰椎间盘退变的生物学机制。 设计、时间及地点：对比观察,于2007-06/2008-12在南方医科大学病理生理实验室完成。 材料：由自愿者提供的正常和退变腰椎间盘组织各6例,年龄21~45岁,其中男9例,女3例;取材范围L3~L5。 方法：氯化铯梯度离心去除正常和退变腰椎间盘组织蛋白多糖,通过固相pH梯度(IPG)等电聚焦和梯度聚丙烯酰胺双向电泳分离蛋白质,分析电泳图像,使用基质辅助激光解吸附飞行时间质谱仪对差异蛋白质点进行分析鉴定。 主要观察指标：正常腰椎间盘及退变腰椎间盘组织IPG等电聚焦双向凝胶电泳结果。 结果：双向电泳显示正常和退变腰椎间盘蛋白质图谱差异显著,从中选取16个差异明显的位点进行质谱仪分析,确定了6种具有显著性意义的差异蛋白质。 结论：双向电泳可有效地分离正常和退变腰椎间盘组织蛋白质,通过质谱仪鉴定可以确定其之间差异蛋白质的性质。     

老年和成年APP转基因小鼠脑蛋白质组2-DE图谱比较

目的:比较老年和成年APP转基因小鼠脑蛋白质组双向电泳(2-DE)图谱差异,从蛋白质水平初步探索老年痴呆发病机制。方法:以固相pH梯度等电聚焦(IPG)为第一向,SDS-PAGE垂直电泳为第二向进行2-DE。图象分析软件Imagemaster 2D Elite分析电泳图谱。结果:老年和成年转基因小鼠脑组织2-DE图谱分别检出964和947个蛋白点。对两张电泳图进行匹配后,发现有17个蛋白点仅在老年转基因小鼠脑蛋白2-DE图谱检测到表达,而有5个蛋白点只在成年转基因小鼠检测到。部分蛋白在2组小鼠脑组织中含量发生了明显变化。结论:初步建立了AD动物模型差异表达蛋白质组学的技术方法;差异点的发现为研究AD机理及治疗AD提供了有益的线索。     

家兔血清蛋白质组双向凝胶电泳技术的建立

背景：家兔血清是基础研究中常用的实验样品，双向凝胶电泳是蛋白质组学中最经典的蛋白分离技术，因此建立稳定的家兔血清蛋白质组双向凝胶电泳技术体系非常重要。 目的：建立家兔血清蛋白分离的双向凝胶电泳技术体系。 设计、时间及地点：单一样本观察，实验于2008-06/07在武警医学院天津市职业与环境危害生物标志物重点实验室完成。 材料：健康家兔6只，由唐山市职业技术学院动物中心提供。 方法：去除高丰度蛋白前后的健康家兔血清样品，分别加入水化上样液使样品中的蛋白充分裂解，还原烷基化后上样，被动水化14 h。等电聚焦电泳后进行SDS-PAGE电泳。凝胶银染后用PDQuest7.4软件进行分析。 主要观察指标：①高丰度蛋白去除效率。②2-DE图谱。 结果：双向电泳图谱清晰，分辨率高，重复性好。未去除高丰度蛋白的血清2-DE图效果优于去除高丰度蛋白后的血清2-DE图。 结论：成功建立家兔血清蛋白质双向凝胶电泳技术，将为进一步开展疾病的血清蛋白质组学研究奠定基础。     

无症状儿童Wilson's病患者血清蛋白质组学研究

目的 寻找无症状Wilson's病(WD)患者血清的特异性生物标记物.方法 选择郑州大学第五附属医院神经内科自2006年7月至2011年10月收治的无症状儿童WD患者20例,同时选择13例正常人作为对照组.运用多重亲和去除柱(MARC)技术去除受试者血清多余蛋白,双向凝胶电泳(2-DE),基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术分别检测和鉴定血清差异性表达蛋白;Westemblotting检测差异蛋白的表达.结果 2-DE检测显示与同性别对照者比较,WD患者血清5个蛋白点上调(点4～7、9),9个蛋白点下调(点l～3、8、10～14).MALDI-TOF-MS鉴定显示点1～3、8、11在男女WD患者血清中均下调,点l、3,点2和点11分别是补体因子B(FB)、C3和α2巨球蛋白(α2M)的前体.Westem blotting检测显示WD患者血清中FB、C3和α2M的表达较同性对照组降低,差异有统计学意义(P＜0.05).结论 补体成分C3、FB及α2M有可能成为诊断早期WD的特异性血清生物学标记.     

多发性硬化的血清蛋白质组学研究

目的 从多发性硬化患者血清蛋白质表达的差异,探索多发性硬化的致病机制并试图寻找该疾病血清的蛋白质标志物.方法 多发性硬化患者与健康志愿者各8例的血清进行比较蛋白质组学研究.去除高丰度蛋白,双向凝胶电泳,图像分析凝胶图谱,寻找差异性蛋白点,经肽质量指纹质谱技术鉴定蛋白质点.结果 多发性硬化患者与对照组20种蛋白质的表达量...     

血管性痴呆与可能为阿尔茨海默病患者的临床生化区别和诊疗

目的探讨阿尔茨海默病(AD)诊断的生化检测新方法,观察AD与血管性痴呆(VaD)的区别以及AD治疗效果。方法选取AD患者(AD组)50例、VaD患者(VaD组)56例和健康老年人(对照组)30名为研究对象。比较3组血清中磷酸化tau蛋白、同型半胱氨酸(Hcy)、维生素B12和胆碱酯酶(ChE)水平的差异,应用胆碱类药物对患者进行治疗。结果 3组被检者的血清磷酸化tau蛋白、Hcy、维生素B12和ChE水平,组间比较均差异有统计学意义(P0.05);AD组治疗后,磷酸化tau蛋白、Hcy、维生素B12和ChE水平与治疗前比较,差异有统计学意义(P0.05)。结论通过血清生化检测磷酸化tau蛋白、Hcy、维生素B12和ChE水平可以初步鉴别AD和VaD,根据不同发病机制给予治疗后疗效显著。     

蛋白质组学技术筛选破裂颅内动脉瘤的血清标志物

目的探讨用双向凝胶电泳结合基质辅助激光解析离子化飞行时间质谱(MALDI-TOF MS)分析技术从血清中筛选颅内动脉瘤标志蛋白的可行性。方法分别采集6例破裂颅内动脉瘤患者和健康成人的血清,进行双向凝胶电泳分离血清总蛋白,考马斯亮蓝染色,全自动斑点处理工作站处理差异蛋白质斑点,MALDI-TOF MS分析获取肽质量指纹图谱,对鉴定的差异蛋白质进行分析。结果两组表达差异2倍以上的蛋白质斑点有81个,质谱鉴定出5个差异蛋白质,在颅内动脉瘤血清中均呈上调表达,即α2-巨球蛋白前体、补体3前体、玻璃黏连蛋白前体、缓激肽和载脂蛋白E3。结论蛋白质组学技术平台为大规模水平筛选破裂颅内动脉瘤血清标志物提供了新方法。     

iTRAQ技术检测烟雾病病人硬脑膜特异性蛋白表达

目的 优化硬脑膜蛋白质的提取方法,筛选烟雾病（MMD）病人硬脑膜特异性表达蛋白质。方法 收集96例MMD和13例非MMD病人的硬脑膜组织,用胶原酶Ⅳ孵育去除硬脑膜表面的血液,用机械破碎或液氮研磨方法提取蛋白质,一维凝胶电泳分离后进行质谱鉴定,用同位素相对标记与绝对定量（iTRAQ）技术进行标记、分离和鉴定差异蛋白质,应用R语言和生物信息学分析筛选MMD相关蛋白质,再应用组织芯片技术验证差异蛋白质表达。结果 胶原酶Ⅳ消化、液氮研磨和十二烷基硫酸钠法提取硬脑膜蛋白质效果较好;iTRAQ技术和生信分析发现23个差异蛋白质,组织芯片结果证实MMD病人硬脑膜组织SLC4A1蛋白表达明显下调。结论 iTRAQ技术可以很好地进行标记、分离和鉴定硬脑膜组织差异蛋白质,SLC4A1可能在MMD发病过程中具有一定的作用。     

蛋白质组学技术鉴定吉兰-巴雷综合征患者血清急性期反应蛋白的表达**☆◆

背景：吉兰-巴雷综合征患者血液中存在与发病有关的抗体、补体和细胞因子,以蛋白质组学技术分离鉴定这些标志蛋白,可为寻找新的药物靶标提供依据。 目的：以蛋白质组技术比较吉兰-巴雷综合征患者与正常对照组血清的差异表达蛋白。 方法：采集确诊的吉兰-巴雷综合征患者和正常者血清各30例,提取血清蛋白质以固相pH梯度等电聚焦为第一向,SDS-PAGE垂直电泳为第二向进行双向电泳,图象分析软件Imagemaster 2D分析电泳图谱,MALDI-TOF/TOF串联质谱鉴定差异表达蛋白。 结果与结论：在吉兰-巴雷综合征患者与正常者中24种蛋白质的表达量显著不同,其中α-2-巨球蛋白,血浆铜蓝蛋白,血清淀粉样P物质,丛生蛋白,抗糜蛋白酶,触珠蛋白,血红素蛋白,α-1-抗胰蛋白酶,血清转铁蛋白等9种蛋白质被鉴定为急性期反应蛋白。结果说明吉兰-巴雷综合征患者血清中急性期反应蛋白表达量发生了明显变化,加深了对吉兰-巴雷综合征发病分子机制的理解。     

邻苯二甲酸二丁酯孕期暴露致仔鼠睾丸膜联蛋白A5的表达差异

背景：国内外关于邻苯二甲酸二丁酯导致雄性生殖系统畸形发生机制的探讨多集中于邻苯二甲酸二丁酯干扰胚胎期睾丸睾酮合成途径的研究，对其基因表达调控的因素及功能蛋白质之间相互干扰的网络效应却并不明了。蛋白质组学能够从整体水平反映蛋白质组分，并筛选功能相关蛋白。 目的：探讨邻苯二甲酸二丁酯胚胎期暴露对胎鼠睾丸蛋白表达谱的影响，分离并鉴定差异表达蛋白质。 设计、时间及地点：随机对照动物实验，实验于2006-08/2007-10在南京医科大学动物实验中心及南京医科大学生殖医学重点实验室完成。 材料：将孕鼠随机分为实验组和对照组，每组5只。妊娠14~18 d。 方法：实验组按800 mg/(kg?d)染毒孕鼠，对照组予大豆油5 mL/d。妊娠21d 取出胚胎大鼠睾丸，提取总蛋白，进行二维凝胶电泳分离和图像分析，筛选出的差异蛋白质点利用质谱技术进行鉴定，并选择关键蛋白进行验证。 主要观察指标：①两组蛋白的电泳差异比较。②酶切，MALDI-TOF分析，数据库检索，生物信息学检索结果。③两组蛋白Western blotting检测及免疫组织化学染色结果。 结果：共筛选出33个差异表达蛋白（t≥2.831，P < 0.05），其中14个通过质谱分析和SwissProt蛋白数据库检索得到鉴定，包括膜联蛋白A5、过氧化物酶6、泛素羧基末端水解酶L1等。运用Western blotting，验证了膜联蛋白A5在实验组表达量明显高于对照组，通过免疫组织化学方法，发现膜联蛋白A5主要定位在胎鼠睾丸Leydig细胞中。 结论：实验运用蛋白质组学方法，建立了邻苯二甲酸二丁酯孕期暴露雄性仔鼠睾丸与正常仔鼠睾丸蛋白质差异表达谱系，鉴定出14个蛋白点，确定了膜联蛋白A5在胎鼠睾丸的定位。     

Proteomic studies of potential cerebrospinal fluid protein markers for Alzheimer's disease

By comparing the cerebrospinal fluid (CSF) proteome between Alzheimer's disease (AD) patients and controls, it may be possible to identify proteins that play a role in the disease process and thus to study the pathogenesis of AD. Two-dimensional gel electrophoresis (2-DE), SYPRO Ruby staining and mass spectrometry were used for clinical screening of disease-influenced CSF proteins in AD patients compared to controls. In order to increase the detection of CSF proteins and to improve the separation of protein isoforms in a 2-D gel, micro-narrow range IPG strips were used. The levels of eight proteins and their isoforms, including apolipoprotein A1, apolipoprotein E, apolipoprotein J, beta-trace, retinol-binding protein, kininogen, alpha-1 antitrypsin, cell cycle progression 8 protein, and alpha-1beta glycoprotein were significantly altered in CSF of AD patients compared to controls. Furthermore, we also used liquid-phase IEF, as a prefractionation step, prior to 2-DE for comparison of CSF proteins between individual AD patients and controls. The levels of 37 proteins spots were altered in AD patients. One of the identified proteins, alpha-2-HS glycoprotein, has not previously been linked to AD. Our study shows that several glycoproteins are altered in AD.     

Analysis of brain proteins in Alzheimer's disease using high-resolution two-dimensional gel electrophoresis.

Two-dimensional gel electrophoresis (2-DE), a method which can be used to analyze the expression of many proteins, is a promising and powerful approach which we have begun to use in the characterization of the complex pathologic processes in Alzheimer's disease (AD). In the present study, a reliable 2-DE database of human brain proteins was created by improving the reproducibility of 2-DE images using an immobilized pH gradient (IPG) for the first dimension gel electrophoresis and Melanie II as the program for data analysis. The brain samples were taken from the temporal cortex of brains at autopsy from 15 AD patients and 15 age-matched controls with non-neurological disorders. About 700 spots were located as consistently expressed proteins in the human brain, all of which were expressed also in AD brains. Comparing the density of spots between AD and normal control, we found that five protein spots were significantly increased, 28 spots were significantly decreased and nine spots were detected only in AD. Two spots among those significantly increased and one spot among those significantly decreased were identified as glial fibrillary acidic proteins. The database of brain proteins in AD constructed for the present study, including the statistical data of density changes in AD, should be a useful beginning for a comprehensive human 2-DE database available via the Internet, which will facilitate further investigation of pathogenic protein alterations in AD.     

Proteomic analysis of plasma from a Tau transgenic mouse

The neurofibrillary tangles (NFTs) formed by the accumulation of abnormal tau filaments have been shown to be involved in Alzheimer's disease (AD) brain degeneration. In this study, a tau transgenic mouse (pNSE/htau23) model was used to monitor changes in protein levels and to search for novel biomarker candidates suitable for the early diagnosis of AD before onset of clinical symptoms. Plasma samples from 2-month (n=13, asymptomatic) and 4-month (n=7, symptomatic) tau transgenic mice were compared to the control group (n=8) by 2-dimensional gel electrophoresis (2-DE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Three proteins, ATP synthase, Adenosine kinase and Regucalcin showed significantly decreased levels in the plasma of tau transgenic mouse, which was further confirmed by Western blotting. This study suggests that these proteins could be used as candidate biomarkers for early diagnosis of AD in combination with previously discovered protein biomarkers.     

Comparative proteomics of cerebrospinal fluid in neuropathologically-confirmed Alzheimer's disease and non-demented elderly subjects

OBJECTIVES: Diagnostic tests able to reveal Alzheimer's disease (AD) in living patients before cognitive ability is destroyed are urgently needed. Such tests must distinguish AD from other dementia causes, as well as differentiate subtle changes associated with normal aging from true pathology emergence. A single biomarker offering such diagnostic and prognostic capacities has eluded identification. Therefore, a valuable test for AD is likely to be based on a specific pattern of change in a set of proteins, rather than a single protein.METHODS: We examined pooled cerebrospinal fluid (CSF) samples obtained from neuropathologically-confirmed AD (n=43) and non-demented control subjects (n=43) using 2-dimensional gel electrophoresis (2DE) proteomic methodology to detect differentially expressed proteins. Proteins exhibiting expression level differences between the pools were recovered and identified using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry.RESULTS: Five differentially-expressed proteins with potential roles in amyloid-beta metabolism and vascular and brain physiology [apolipoprotein A-1 (Apo A-1), cathepsin D (CatD), hemopexin (HPX), transthyretin (TTR), and two pigment epithelium-derived factor (PEDF) isoforms] were identified. Apo A-1, CatD and TTR were significantly reduced in the AD pool sample, while HPX and the PEDF isoforms were increased in AD CSF.DISCUSSION: These results suggest that multi-factor proteomic pattern analysis of the CSF may provide a means to diagnose and assess AD.     

不同严重程度阿尔茨海默病患者血清miR-128,miR-223表达水平变化与炎症反应及认知功能的相关性分析

目的 探讨不同严重程度阿尔茨海默病(Alzheimer’s disease,AD)患者血清微小RNA(MicroRNA,miR)-128,miR-223表达水平变化与炎症反应及认知功能的相关性。方法 选择2018年6月-2020年1月本院收治的200例AD患者(AD组),根据临床痴呆评定量表(Clinical dementia rating scale,CDR)评分将AD患者分为轻度组(CDR评分1分,66例)、中度组(CDR评分2分,83例)、重度组(CDR评分3,51例)3个亚组,另选择207例体检健康志愿者为对照组; 采用简易智能精神状态检查量表(Mini-mental state examination,MMSE)评估AD患者认知功能; 检测所有受试者血清miR-128,miR-223表达水平; 检测AD患者血清白介素-6(Interleukin-6,IL-6)、白介素-1β(Interleukin-1,IL-1β)、肿瘤坏死因子-α(Tumor necrosis factor-,TNF-α)、C反应蛋白(C-reactive protein,CRP)水平; 分析血清miR-128,miR-223表达水平与TNF-α,IL-1β,IL-6,CRP水平、MMSE总分的相关性。结果 AD组血清miR-128表达水平高于对照组(P<0.05),miR-223表达水平低于对照组(P<0.05)。重度组血清miR-128表达水平、TNF-α,IL-1β,IL-6,CRP水平高于中度和轻度组(P<0.05),且中度组高于轻度组(P<0.05); 重度组血清miR-223表达水平、MMSE总分低于中度和轻度组(P<0.05),且中度组低于轻度组(P<0.05)。miR-128表达水平与TNF-α,IL-1β,IL-6,CRP呈正相关(r≥0.496,P<0.05),与MMSE总分呈负相关(r =-0.571,P<0.05); miR-223表达水平与TNF-α,IL-1β,IL-6,CRP呈负相关(r ≤-0.572,P<0.05),与MMSE总分呈正相关(r=0.531,P<0.05)。结论 AD患者血清miR-128表达水平上调,miR-223表达水平下调,两者异常变化可能诱导炎症反应,进而参与AD患者认知功能损伤过程。     

A new procedure for detecting brain-specific proteins in cerebrospinal fluid

Summary We have developed a new procedure, including three affinity chromatography steps, micro-reversed phase high pressure liquid chromatography (mR-HPLC) and Western blotting/mass spectrometric analysis to study central nervous system (CNS) specific proteins in human cerebrospinal fluid (CSF) in order to find biochemical markers for neuronal and synaptic function and pathology in degenerative brain disorders. After the three affinity chromatography steps, intended to remove interfering serum proteins from CSF, mR-HPLC revealed four major peaks, which by both Western blotting and mass spectrometric analyses were found to correspond to 2-microglobulin, cystatin C, transthyretin (TTR) and asialotransferrin. When comparing these peaks in CSF from Alzheimer's disease (AD) patients and age-matched healthy controls, a reduction of the brain-specific TTR was found. Therefore we quantified TTR in CSF and serum samples from 8 patients with early onset AD (EAD), 18 patients with late onset AD (LAD), 8 patients with vascular dementia (VAD) and 18 healthy individuals using a nephelometric method. CSF-TTR was divided into barrier-dependent and barrier-independent TTR. The barrier-independent i.e. brain-specific TTR was significantly reduced in the EAD group compared to the controls. Transthyretin has been found to be present in the senile plaques in AD, and to specifically bind to /A4 protein, the major component of the amyloid deposits in AD. Therefore, the reduction of the transthyretin-isoform in CSF in AD may reflect an absorption of transthyretin to the amyloid deposits in the senile plaques.     

Tyrosine hydroxylase and norepinephrine transporter mRNA expression in the locus coeruleus in Alzheimer's disease

Despite the loss of locus coeruleus (LC) noradrenergic neurons in Alzheimer's disease (AD), cerebrospinal fluid norepinephrine (NE) levels are normal or increased in AD. This paradox suggests compensatory upregulation of NE synthetic capacity or downregulation of the NE transporter (NET) in the remaining LC neurons. LC tyrosine hydroxylase (TH) mRNA expression in the LC was measured in AD subjects (n=5) and in age and gender comparable non-demented subjects (n=6). When AD subjects were divided into those still ambulatory prior to death (CDR 3/4) and those in a prolonged 'vegetative' state prior to death (CDR 5), differences among groups became apparent at specific levels of the LC. In CDR 3/4 AD subjects there was increased TH mRNA expression per neuron compared to non-demented subjects in the caudal half of the LC. However, expression of NET mRNA in the same subjects was not significantly different at any level of the LC. These preliminary results suggest an upregulation of NE biosynthetic capacity in at least some LC neurons in AD prior to the very late stage of the disease.     

Proteome analysis of brain proteins in Alzheimer's disease: subproteomics following sequentially extracted protein preparation

Quantitative proteome analysis of Alzheimer's disease (AD) brains was performed using two-dimensional (2-D) gels in order to find out the pathological protein expression in AD. We sequentially extracted brain proteins using two distinct sample solutions, yielding different protein fractions (fraction A and B). These fractions showed distinct 2-DE patterns with high resolution and excellent reproducibility. In fraction A (solubilized by urea and Nonidet P-40 (NP-40)), approximately 1300 protein spots were detected, and the relative volume (%VOL) significantly increased in five spots and significantly decreased in 10 spots in AD. The proteins identified include enzymes, molecular chaperones and cytoskeletal proteins. In fraction B (solubilized by urea, thiourea, N-decyl-N,N-dimethyl-3-ammonio-1-propane sulfonate (SB3-10) and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS)), over 500 protein spots were detected in the 2-DE data analysis. The %VOL of three spots was significantly increased in AD. Two of these spots were identified as glial fibrillary acidic protein (GFAP) using mass spectrometry. These results suggest that subproteomics following sequentially extracted brain proteins is a useful method for the analysis of brain extracts containing hydrophobic proteins. Our findings will prompt further study on disease-linked proteins for the investigation of AD pathogenesis and the quest for disease markers.     

AD患者外周血单核细胞中TLR-4表达 水平变化的临床意义

目的 探讨外周血单核细胞Toll样受体-4(Toll-like receptor 4,TLR-4)的表达水平变化与AD发病及进展的关系。方法 检测阿尔茨海默病(Alzheimer's disease,AD)及轻度认知功能障碍(Mild cognitive impairment,MCI)患者及同年龄正常对照者(Healthy Controls,HC)外周血单核细胞Toll样受体-4(Toll-like receptor 4,TLR-4)的表达水平; 采集并分离AD(n=28)、MCI(n=26)及NC组(n=20)外周血单核细胞; 用实时荧光定量PCR(Quantitative Real-Time,Q-PCR)、流式细胞术(Flow Cytometry)检测TLR-4的表达水平; 双抗体夹心法(Double antibody sandwich method,ELISA)检测各组血清中肿瘤坏死因子(Tumor necrosis factor-α(TNF-α)、白介素6(Interleukin 6,IL-6)的水平。结果 与HC组比较,AD患者外周血单核细胞TLR-4表达水平均明显上调(P均<0.05)。MCI组略有上升,但无统计学意义; AD患者外周血单核细胞TLR-4表达水平与血清TNF-a、IL-6水平呈正相关(r=0.3885和0.3270,P均<0.05)。结论 外周血单个核细胞TLR-4表达水平上调提示炎性机制在AD的发病中发挥了作用,TLR4可作为评估疾病进展的潜在生物学标志物。     

CSF in Alzheimer's disease. Studies on blood-brain barrier function and intrathecal protein synthesis

Serum and cerebrospinal fluid (CSF) from 22 ambulatory and 10 institutionalised patients with Alzheimer's disease (AD) and 22 age-matched controls were assayed nephelometrically for concentrations of IgG, IgA, IgM, haptoglobin, transferrin, prealbumin and albumin. The CSF/serum ratio and index were calculated for each protein. In the CSF of ambulatory patients IgG, transferrin and albumin were elevated while the institutionalised patients had higher IgG and IgA levels compared to the controls. The CSF haptoglobin was elevated in institutionalised AD patients compared to those who were ambulatory. The CSF/serum ratio for albumin was elevated in both groups. An increase in the IgG ratio was also found in both groups. The ratios for haptoglobin and prealbumin were markedly increased in the institutionalised patients. CSF indices gave no evidence for increased intrathecal synthesis of any of the proteins investigated. The increased CSF/serum ratios for IgG and albumin and also the higher CSF albumin in patients with AD suggest an increased blood-brain barrier permeability in this disease. The high prealbumin ratio may be related to amyloidogenesis often present in AD.