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Find video protocols related to scientific articles indexed in Pubmed.
Highly potent soluble amyloid-? seeds in human Alzheimer brain but not cerebrospinal fluid.
Brain
PUBLISHED: 09-10-2014
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The soluble fraction of brain samples from patients with Alzheimer's disease contains highly biologically active amyloid-? seeds. In this study, we sought to assess the potency of soluble amyloid-? seeds derived from the brain and cerebrospinal fluid. Soluble Alzheimer's disease brain extracts were serially diluted and then injected into the hippocampus of young, APP transgenic mice. Eight months later, seeded amyloid-? deposition was evident even when the hippocampus received subattomole amounts of brain-derived amyloid-?. In contrast, cerebrospinal fluid from patients with Alzheimer's disease, which contained more than 10-fold higher levels of amyloid-? peptide than the most concentrated soluble brain extracts, did not induce detectable seeding activity in vivo. Similarly, cerebrospinal fluid from aged APP-transgenic donor mice failed to induce cerebral amyloid-? deposition. In comparison to the soluble brain fraction, cerebrospinal fluid largely lacked N-terminally truncated amyloid-? species and exhibited smaller amyloid-?-positive particles, features that may contribute to the lack of in vivo seeding by cerebrospinal fluid. Interestingly, the same cerebrospinal fluid showed at least some seeding activity in an in vitro assay. The present results indicate that the biological seeding activity of soluble amyloid-? species is orders of magnitude greater in brain extracts than in the cerebrospinal fluid.
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Capillary isoelectric focusing immunoassay as a new nanoscale approach for the detection of oligoclonal bands.
Electrophoresis
PUBLISHED: 07-16-2014
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The detection of oligoclonal bands (OCBs) in cerebrospinal fluid is an indicator of intrathecal synthesis of immunoglobulins which is a neurochemical sign of chronic inflammatory brain diseases. Intrathecally synthesized IgGs are typically observed in patients with multiple sclerosis. The current standard protocol for the detection of OCBs is isoelectric focusing on agarose or polyacrylamide gels followed by immunoblotting or silver staining. These methods are time consuming, show substantial inter-laboratory variation and cannot be used in a high throughput-approach. We have developed a new nanoscale method for the detection of OCBs based on automated capillary isoelectric focusing followed by immunological detection. Evidence for intrathecal IgG synthesis was found in all tested patients (n = 27) with multiple sclerosis, even in two subjects who did not have oligoclonal bands according to standard methods. The test specificity was at 97.5% (n = 19). Our findings indicate that the novel OCB-CIEF-immunoassay is suitable for the rapid and highly sensitive detection of OCBs in clinical samples. Furthermore, the method allows for a higher sample throughput than the current standard methods. This article is protected by copyright. All rights reserved.
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SUCLG2 identified as both a determinator of CSF A?1-42 levels and an attenuator of cognitive decline in Alzheimer's disease.
Hum. Mol. Genet.
PUBLISHED: 07-15-2014
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Cerebrospinal fluid amyloid-beta 1-42 (A?1-42) and phosphorylated Tau at position 181 (pTau181) are biomarkers of Alzheimer's disease (AD). We performed an analysis and meta-analysis of genome-wide association study data on A?1-42 and pTau181 in AD dementia patients followed by independent replication. An association was found between A?1-42 level and a single-nucleotide polymorphism in SUCLG2 (rs62256378) (P = 2.5×10(-12)). An interaction between APOE genotype and rs62256378 was detected (P = 9.5 × 10(-5)), with the strongest effect being observed in APOE-?4 noncarriers. Clinically, rs62256378 was associated with rate of cognitive decline in AD dementia patients (P = 3.1 × 10(-3)). Functional microglia experiments showed that SUCLG2 was involved in clearance of A?1-42.
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Spot quantification in two dimensional gel electrophoresis image analysis: comparison of different approaches and presentation of a novel compound fitting algorithm.
BMC Bioinformatics
PUBLISHED: 05-28-2014
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Various computer-based methods exist for the detection and quantification of protein spots in two dimensional gel electrophoresis images. Area-based methods are commonly used for spot quantification: an area is assigned to each spot and the sum of the pixel intensities in that area, the so-called volume, is used a measure for spot signal. Other methods use the optical density, i.e. the intensity of the most intense pixel of a spot, or calculate the volume from the parameters of a fitted function.
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Investigation of the role of rare TREM2 variants in frontotemporal dementia subtypes.
Neurobiol. Aging
PUBLISHED: 04-28-2014
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Frontotemporal dementia (FTD) is a clinically and genetically heterogeneous disorder. Rare TREM2 variants have been recently identified in families affected by FTD-like phenotype. However, genetic studies of the role of rare TREM2 variants in FTD have generated conflicting results possibly because of difficulties on diagnostic accuracy. The aim of the present study was to investigate associations between rare TREM2 variants and specific FTD subtypes (FTD-S). The entire coding sequence of TREM2 was sequenced in FTD-S patients of Spanish (n = 539) and German (n = 63) origin. Genetic association was calculated using Fisher exact test. The minor allele frequency for controls was derived from in-house genotyping data and publicly available databases. Seven previously reported rare coding variants (p.A28V, p.W44X, p.R47H, p.R62H, p.T66M, p.T96K, and p.L211P) and 1 novel missense variant (p.A105T) were identified. The p.R47H variant was found in 4 patients with FTD-S. Two of these patients showed cerebrospinal fluid pattern of amyloid beta, tau, and phosphorylated-tau suggesting underlying Alzheimer's disease (AD) pathology. No association was found between p.R47H and FTD-S. A genetic association was found between p.T96K and FTD-S (p = 0.013, odds ratio = 4.23, 95% Confidence Interval [1.17-14.77]). All 6 p.T96K patients also carried the TREM2 variant p.L211P, suggesting linkage disequilibrium. The remaining TREM2 variants were found in 1 patient, respectively, and were absent in controls. The present findings provide evidence that p.T96K is associated with FTD-S and that p.L211P may contribute to its pathogenic effect. The data also suggest that p.R47H is associated with an FTD phenotype that is characterized by the presence of underlying AD pathology.
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High-fat diet induced isoform changes of the Parkinson's disease protein DJ-1.
J. Proteome Res.
PUBLISHED: 03-28-2014
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Genetic and environmental factors mediate via different physiological and molecular processes a shifted energy balance leading to overweight and obesity. To get insights into the underlying processes involved in energy intake and weight gain, we compared hypothalamic tissue of mice kept on a high-fat or control diet for 10 days by a proteomic approach. Using two-dimensional difference gel electrophoresis in combination with LC-MS/MS, we observed significant abundance changes in 15 protein spots. One isoform of the protein DJ-1 was elevated in the high-fat diet group in three different mouse strains SWR/J, C57BL/6N, and AKR/J analyzed. Large-scale validation of DJ-1 isoforms in individual samples and tissues confirmed a shift in the pattern of DJ-1 isoforms toward more acidic isoforms in several brain and peripheral tissues after feeding a high-fat diet for 10 days. The identification of oxidation of cysteine 106 as well as 2-succinyl modification of the same residue by mass spectrometry not only explains the isoelectric shift of DJ-1 but also links our results to similar shifts of DJ-1 observed in neurodegenerative disease states under oxidative stress. We hypothesize that DJ-1 is a common physiological sensor involved in both nutrition-induced effects and neurodegenerative disease states.
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Astrocytes and microglia but not neurons preferentially generate N-terminally truncated A? peptides.
Neurobiol. Dis.
PUBLISHED: 03-17-2014
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The neuropathological hallmarks of Alzheimer's disease include extracellular neuritic plaques and neurofibrillary tangles. The neuritic plaques contain ?-amyloid peptides (A? peptides) as the major proteinaceous constituent and are surrounded by activated microglia and astrocytes as well as dystrophic neurites. N-terminally truncated forms of A? peptides are highly prevalent in neuritic plaques, including A? 3-x beginning at Glu eventually modified to pyroglutamate (A? N3pE-x), A? 2-x, A? 4-x, and A? 5-x. The precise origin of the different N-terminally modified A? peptides currently remains unknown. To assess the contribution of specific cell types to the formation of different N-terminally truncated A? peptides, supernatants from serum-free primary cell cultures of chicken neurons, astrocytes, and microglia, as well as human astrocytes, were analyzed by A?-ELISA and one- and two-dimensional SDS-urea polyacrylamide gel electrophoresis followed by immunoblot analysis. To evaluate the contribution of ?- and ?-secretase to the generation of N-terminally modified A?, cultured astrocytes were treated with membrane-anchored "tripartite ?-secretase (BACE1) inhibitors" and the ?-secretase inhibitor DAPT. Neurons, astrocytes, and microglia each exhibited cell type-specific patterns of secreted A? peptides. Neurons predominantly secreted A? peptides that begin at Asp1, whereas those released from astrocytes and microglia included high proportions of N-terminally modified A? peptides, presumably including A? 2/3-x and 4/5-x. The inhibition of BACE1 reduced the amount of A? 1-x in cell culture supernatants but not the amount of A? 2-x.
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Direct analytical sample quality assessment for biomarker investigation: qualifying cerebrospinal fluid samples.
Proteomics
PUBLISHED: 03-09-2014
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Measurement of biochemical markers represents an important aid to clinicians in the early diagnosis and prognosis of neurological diseases. Many factors can contribute to increase the chances that a biomarker study becomes successful. In a cerebrospinal fluid analysis (CSF), more than 84% of laboratory errors can be attributed to several preanalytical variables that include CSF collection, storage, and freeze thawing cycles. In this concept paper, we focus on some critical issues arising from basic proteomics investigation in order to highlight some key elements of CSF quality control. Furthermore, we propose a direct assessment of sample quality (DASQ) by applying a fast MALDI-TOF-MS methodology to evaluate molecular features of sample degradation and oxidation. We propose DASQ as a fast and simple initial step to be included in large-scale projects for neurological biomarker studies. In fact, such a procedure will improved the development of standardized protocols in order to have well-characterized CSF biobanks.
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Genetic interaction of PICALM and APOE is associated with brain atrophy and cognitive impairment in Alzheimer's disease.
Alzheimers Dement
PUBLISHED: 03-06-2014
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Evidence has emerged indicating that the ?4 allele of APOE and PICALM interact in conferring risk of Alzheimer's disease (AD). The biologic basis of this interaction is unclear, but it is likely to have phenotypic relevance and contribute to the structural and clinical heterogeneity of AD.
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Multisite longitudinal reliability of tract-based spatial statistics in diffusion tensor imaging of healthy elderly subjects.
Neuroimage
PUBLISHED: 02-19-2014
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Large-scale longitudinal neuroimaging studies with diffusion imaging techniques are necessary to test and validate models of white matter neurophysiological processes that change in time, both in healthy and diseased brains. The predictive power of such longitudinal models will always be limited by the reproducibility of repeated measures acquired during different sessions. At present, there is limited quantitative knowledge about the across-session reproducibility of standard diffusion metrics in 3T multi-centric studies on subjects in stable conditions, in particular when using tract based spatial statistics and with elderly people. In this study we implemented a multi-site brain diffusion protocol in 10 clinical 3T MRI sites distributed across 4 countries in Europe (Italy, Germany, France and Greece) using vendor provided sequences from Siemens (Allegra, Trio Tim, Verio, Skyra, Biograph mMR), Philips (Achieva) and GE (HDxt) scanners. We acquired DTI data (2 × 2 × 2 mm(3), b = 700 s/mm(2), 5 b0 and 30 diffusion weighted volumes) of a group of healthy stable elderly subjects (5 subjects per site) in two separate sessions at least a week apart. For each subject and session four scalar diffusion metrics were considered: fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial (AD) diffusivity. The diffusion metrics from multiple subjects and sessions at each site were aligned to their common white matter skeleton using tract-based spatial statistics. The reproducibility at each MRI site was examined by looking at group averages of absolute changes relative to the mean (%) on various parameters: i) reproducibility of the signal-to-noise ratio (SNR) of the b0 images in centrum semiovale, ii) full brain test-retest differences of the diffusion metric maps on the white matter skeleton, iii) reproducibility of the diffusion metrics on atlas-based white matter ROIs on the white matter skeleton. Despite the differences of MRI scanner configurations across sites (vendors, models, RF coils and acquisition sequences) we found good and consistent test-retest reproducibility. White matter b0 SNR reproducibility was on average 7 ± 1% with no significant MRI site effects. Whole brain analysis resulted in no significant test-retest differences at any of the sites with any of the DTI metrics. The atlas-based ROI analysis showed that the mean reproducibility errors largely remained in the 2-4% range for FA and AD and 2-6% for MD and RD, averaged across ROIs. Our results show reproducibility values comparable to those reported in studies using a smaller number of MRI scanners, slightly different DTI protocols and mostly younger populations. We therefore show that the acquisition and analysis protocols used are appropriate for multi-site experimental scenarios.
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Genetic variation at the CELF1 (CUGBP, elav-like family member 1 gene) locus is genome-wide associated with Alzheimer's disease and obesity.
Am. J. Med. Genet. B Neuropsychiatr. Genet.
PUBLISHED: 02-05-2014
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Deviations from normal body weight are observed prior to and after the onset of Alzheimer's disease (AD). Midlife obesity confers increased AD risk in later life, whereas late-life obesity is associated with decreased AD risk. The role of underweight and weight loss for AD risk is controversial. Based on the hypothesis of shared genetic variants for both obesity and AD, we analyzed the variants identified for AD or obesity from genome-wide association meta-analyses of the GERAD (AD, cases?=?6,688, controls?=?13,685) and GIANT (body mass index [BMI] as measure of obesity, n?=?123,865) consortia. Our cross-disorder analysis of genome-wide significant 39 obesity SNPs and 23 AD SNPs in these two large data sets revealed that: (1) The AD SNP rs10838725 (pAD ?=?1.1?×?10(-08)) at the locus CELF1 is also genome-wide significant for obesity (pBMI ?=?7.35?×?10(-09) ). (2) Four additional AD risk SNPs were nominally associated with obesity (rs17125944 at FERMT2, pBMI ?=?4.03?×?10(-05), pBMI?corr ?=?2.50?×?10(-03) ; rs3851179 at PICALM; pBMI ?=?0.002, rs2075650 at TOMM40/APOE, pBMI ?=?0.024, rs3865444 at CD33, pBMI ?=?0.024). (3) SNPs at two of the obesity risk loci (rs4836133 downstream of ZNF608; pAD ?=?0.002 and at rs713586 downstream of RBJ/DNAJC27; pAD ?=?0.018) were nominally associated with AD risk. Additionally, among the SNPs used for confirmation in both studies the AD risk allele of rs1858973, with an AD association just below genome-wide significance (pAD ?=?7.20?×?10(-07)), was also associated with obesity (SNP at IQCK/GPRC5B; pBMI ?=?5.21?×?10(-06) ; pcorr ?=?3.24?×?10(-04)). Our first GWAS based cross-disorder analysis for AD and obesity suggests that rs10838725 at the locus CELF1 might be relevant for both disorders.
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Serum albumin correlates with affective prosody in adult males with attention-deficit hyperactivity disorder.
Psychiatry Res
PUBLISHED: 02-03-2014
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The aim of this study was to determine the relationship between serum albumin, affective prosody, and symptoms of attention-deficit hyperactivity disorder (ADHD) found coincidentally in a recently published study. Here, serum albumin levels were assessed as a covariate. Twenty healthy male adults (controls) and 20 adult male patients with ADHD participated in the study on two study days. Serum albumin levels and performance in an affective prosody task were assessed, and correlations were determined. Serum albumin had a significant correlation with performance on an affective prosody task on both of the 2 study days. The same correlations were not significant in the healthy control group. There was no difference in the serum albumin level between patients with ADHD and healthy controls. The association between serum albumin and affective prosody in adults with ADHD is a novel finding. However, to date, there is no clear theory that explains this association. Future research should analyze whether serum albumin influences causes changes in performance in affective prosody using experimental designs.
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Memory concerns, memory performance and risk of dementia in patients with mild cognitive impairment.
PLoS ONE
PUBLISHED: 01-01-2014
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Concerns about worsening memory ("memory concerns"; MC) and impairment in memory performance are both predictors of Alzheimer's dementia (AD). The relationship of both in dementia prediction at the pre-dementia disease stage, however, is not well explored. Refined understanding of the contribution of both MC and memory performance in dementia prediction is crucial for defining at-risk populations. We examined the risk of incident AD by MC and memory performance in patients with mild cognitive impairment (MCI).
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Mismatch negativity latency and cognitive function in schizophrenia.
PLoS ONE
PUBLISHED: 01-01-2014
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The Mismatch Negativity (MMN) is an event-related potential (ERP) sensitive to early auditory deviance detection and has been shown to be reduced in schizophrenia patients. Moreover, MMN amplitude reduction to duration deviant tones was found to be related to functional outcomes particularly, to neuropsychological (working memory and verbal domains) and psychosocial measures. While MMN amplitude is thought to be correlated with deficits of early sensory processing, the functional significance of MMN latency remains unclear so far. The present study focused on the investigation of MMN in relation to neuropsychological function in schizophrenia.
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Early diagnosis of neurodegenerative diseases - the long awaited Holy Grail and bottleneck of modern brain research - 19th HUPO BPP workshop: May 22-24, 2013, Dortmund, Germany.
Proteomics
PUBLISHED: 10-11-2013
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The HUPO Brain Proteome Project (HUPO BPP) held its 19th workshop in Dortmund, Germany, from May 22 to 24, 2013. The focus of the spring workshop was on strategies and developments concerning early diagnosis of neurodegenerative diseases.
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Hypocretin in cerebrospinal fluid is positively correlated with Tau and pTau.
Neurosci. Lett.
PUBLISHED: 08-22-2013
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It has been suggested that sleep-wake regulation as well as hypocretins play a role in the pathophysiology of Alzheimers disease. We analyzed A?40, A?42, Tau protein, phosphorylated Tau (pTau) protein as well as hypocretin-1 concentrations in the CSF of a detection sample of 10 patients with Alzheimers disease (AD) as well as 10 age- and gender-matched patients with major depression as a comparison group of different pathology. In order to replicate the findings, we used a confirmation sample of 17 AD patients and 8 patients with major depression. We found hypocretin-1 concentrations in CSF not to differ between patients with depression and AD. However, hypocretin-1 was significantly related to Tau (r=0.463, p<0.001) and pTau (r=0.630, p<0.0001). These effects were more pronounced in depressed patients when compared to AD patients. We conclude that hypocretin-1 may play a role in the metabolism of Tau proteins across different diagnostic entities including AD. It has to be determined whether there is a causal relationship between hypocretin-1 and Tau as well as pTau.
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Analysis of amino-terminal variants of amyloid-? peptides by capillary isoelectric focusing immunoassay.
Anal. Chem.
PUBLISHED: 08-14-2013
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Here we present a novel assay for the separation and detection of amino-terminal amyloid-? (A?) peptide variants by capillary isoelectric focusing (CIEF) immunoassay. Specific amino-terminally truncated A? peptides appear to be generated by ?-secretase (BACE1)-independent mechanisms and have previously been observed in cerebrospinal fluid (CSF) after BACE1 inhibitor treatment in an animal model. CIEF immunoassay sensitivity is sufficient to detect total A? in CSF without preconcentration. To analyze low-abundance amino-terminally truncated A? peptides from cell culture supernatants, we developed a CIEF-compatible immunoprecipitation protocol, allowing for selective elution of A? peptides with very low background. CIEF immunoassay and immunoprecipitation mass spectrometry analysis identified peptides starting at residue Arg(5) as the main amino-terminal A? variants produced in the presence of tripartite BACE1 inhibitor in our cell culture model. The CIEF immunoassay allows for robust relative quantification of A? peptide patterns in biological samples. To assess the future possibility of absolute quantification, we have prepared the A? peptides A?(x-10), A?(x-16), and A?(5-38(D23S)) by using solid phase peptide synthesis as internal standards for the CIEF immunoassay.
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Comparison of the nasal release of IL-4, IL-10, IL-17, CCL13/MCP-4, and CCL26/eotaxin-3 in allergic rhinitis during season and after allergen challenge.
Am J Rhinol Allergy
PUBLISHED: 07-26-2013
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Allergic rhinitis is an inflammatory disease characterized by local overproduction of type 2 cytokines and tissue eosinophilia. Recent research suggests the involvement of additional cytokines such as IL-17, chemokine (C-C motif) ligand (CCL) 26/eotaxin-3, and CCL13/monocyte chemoattractant protein-4 (MCP-4) in its pathophysiology. Furthermore, bronchial epithelial cells treated with IL-17 and type 2 cytokines distinctively up-regulated eotaxin-3 gene expression. In this study we investigated the kinetics of IL-4, IL-10, IL-17, eotaxin-3, and MCP-4 in seasonal allergic rhinitis volunteers after nasal allergen challenge (NAC) and their release during natural pollen exposure.
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Brain morphometry reproducibility in multi-center 3T MRI studies: a comparison of cross-sectional and longitudinal segmentations.
Neuroimage
PUBLISHED: 03-25-2013
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Large-scale longitudinal multi-site MRI brain morphometry studies are becoming increasingly crucial to characterize both normal and clinical population groups using fully automated segmentation tools. The test-retest reproducibility of morphometry data acquired across multiple scanning sessions, and for different MR vendors, is an important reliability indicator since it defines the sensitivity of a protocol to detect longitudinal effects in a consortium. There is very limited knowledge about how across-session reliability of morphometry estimates might be affected by different 3T MRI systems. Moreover, there is a need for optimal acquisition and analysis protocols in order to reduce sample sizes. A recent study has shown that the longitudinal FreeSurfer segmentation offers improved within session test-retest reproducibility relative to the cross-sectional segmentation at one 3T site using a nonstandard multi-echo MPRAGE sequence. In this study we implement a multi-site 3T MRI morphometry protocol based on vendor provided T1 structural sequences from different vendors (3D MPRAGE on Siemens and Philips, 3D IR-SPGR on GE) implemented in 8 sites located in 4 European countries. The protocols used mild acceleration factors (1.5-2) when possible. We acquired across-session test-retest structural data of a group of healthy elderly subjects (5 subjects per site) and compared the across-session reproducibility of two full-brain automated segmentation methods based on either longitudinal or cross-sectional FreeSurfer processing. The segmentations include cortical thickness, intracranial, ventricle and subcortical volumes. Reproducibility is evaluated as absolute changes relative to the mean (%), Dice coefficient for volume overlap and intraclass correlation coefficients across two sessions. We found that this acquisition and analysis protocol gives comparable reproducibility results to previous studies that used longer acquisitions without acceleration. We also show that the longitudinal processing is systematically more reliable across sites regardless of MRI system differences. The reproducibility errors of the longitudinal segmentations are on average approximately half of those obtained with the cross sectional analysis for all volume segmentations and for entorhinal cortical thickness. No significant differences in reliability are found between the segmentation methods for the other cortical thickness estimates. The average of two MPRAGE volumes acquired within each test-retest session did not systematically improve the across-session reproducibility of morphometry estimates. Our results extend those from previous studies that showed improved reliability of the longitudinal analysis at single sites and/or with non-standard acquisition methods. The multi-site acquisition and analysis protocol presented here is promising for clinical applications since it allows for smaller sample sizes per MRI site or shorter trials in studies evaluating the role of potential biomarkers to predict disease progression or treatment effects.
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Intravenous immunoglobulin for treatment of mild-to-moderate Alzheimers disease: a phase 2, randomised, double-blind, placebo-controlled, dose-finding trial.
Lancet Neurol
PUBLISHED: 01-31-2013
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Three small trials suggest that intravenous immunoglobulin can affect biomarkers and symptoms of mild-to-moderate Alzheimers disease. We tested the safety, effective dose, and infusion interval of intravenous immunoglobulin in such patients.
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Challenges in modern biomarker discovery--17th HUPO BPP workshop: May 24-25, 2012, Sao Paulo, Brazil.
Proteomics
PUBLISHED: 01-24-2013
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The HUPO Brain Proteome Project (HUPO BPP) held its 17(th) workshop in Sao Paulo, Brazil, on May 24 and 25, 2012. The focus was on the progress on the Human Brain Proteome Atlas as well as ideas, strategies and methodological aspects in clinical neuroproteomics.
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Genome-wide association study of vascular dementia.
Stroke
PUBLISHED: 11-23-2011
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Most studies investigating the genetics of dementia have focused on Alzheimer disease, but little is known about the genetics of vascular dementia. The aim of our study was to identify new loci associated with vascular dementia.
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Clinical aspects of neurodegenerative diseases - 15th HUPO BPP Workshop April 8-9, 2011, Bochum, Germany.
Proteomics
PUBLISHED: 11-03-2011
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The HUPO Brain Proteome Project (HUPO BPP) held its 15th workshop in Bochum, Germany, from April 8th to 9th, 2011 directly after the Proteomic Forum 2011 in Berlin. Like on every spring workshop, the focus was more on clinical aspects, so that especially clinicians participated in this workshop.
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Atrophy outcomes in multicentre clinical trials on Alzheimers disease: effect of different processing and analysis approaches on sample sizes.
World J. Biol. Psychiatry
PUBLISHED: 09-13-2011
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Structural MRI markers may serve as surrogate endpoints in clinical trials on disease modification in Alzheimers disease (AD). Here, we used a longitudinal MRI data set of total brain and cortical grey matter volumes from 66 patients with AD recruited across seven centres of the German Dementia Competence Network. We compared effect size estimates for the detection of a 25% reduction of atrophy progression between a priori segmentation of brain tissue, implementing an anatomical model of brain tissue distribution, and a posteriori segmentation that was not informed by an anatomical model. Additionally, we compared effect size estimates between fixed effects analysis and a mixed effects model, implementing a random effects term to account for variable spacing of observation times. A priori segmentation reduced the required sample size by 50%. Introducing a random effects term for time led to an additional 50% reduction of required samples sizes compared to fixed effects analysis. In summary, using a priori segmentation with mixed effects analysis reduced the sample size to detect clinically relevant treatment effects more than fourfold. The implementation of mixed effects models will enhance the power to detect treatment effects also with other classes of biological endpoints including molecular biomarkers of disease.
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Beta-amyloid peptide variants in brains and cerebrospinal fluid from amyloid precursor protein (APP) transgenic mice: comparison with human Alzheimer amyloid.
J. Biol. Chem.
PUBLISHED: 07-27-2011
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In this study, we report a detailed analysis of the different variants of amyloid-? (A?) peptides in the brains and the cerebrospinal fluid from APP23 transgenic mice, expressing amyloid precursor protein with the Swedish familial Alzheimer disease mutation, at different ages. Using one- and two-dimensional gel electrophoresis, immunoblotting, and mass spectrometry, we identified the A? peptides A?(1-40), -(1-42), -(1-39), -(1-38), -(1-37), -(2-40), and -(3-40) as well as minor amounts of pyroglutamate-modified A? (A?(N3pE)) and endogenous murine A? in brains from 24-month-old mice. Chemical modifications of the N-terminal amino group of A? were identified that had clearly been introduced during standard experimental procedures. To address this issue, we additionally applied amyloid extraction in ultrapure water. Clear differences between APP23 mice and Alzheimer disease (AD) brain samples were observed in terms of the relative abundance of specific variants of A? peptides, such as A?(N3pE), A?(1-42), and N-terminally truncated A?(2/3-42). These differences to human AD amyloid were also noticed in a related mouse line transgenic for human wild type amyloid precursor protein. Taken together, our findings suggest different underlying molecular mechanisms driving the amyloid deposition in transgenic mice and AD patients.
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Creating a human brain proteome atlas--13th HUPO BPP Workshop March 30-31, 2010, Ochang, Korea.
Proteomics
PUBLISHED: 07-01-2011
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The HUPO Brain Proteome Project (HUPO BPP) held its 13th workshop in Ochang from March 30th to 31st, 2010 prior to the Korean HUPO 10th Annual International Proteomics Conference. The principal aim of this project is to obtain a better understanding of neurodiseases and aging with the ultimate objective of discovering prognostic and diagnostic biomarkers, in addition to the development of novel diagnostic techniques and new medications. The attendees came together to discuss progress in the clinical neuroproteomics of human and to define the needs and guidelines required for more advanced proteomics approaches.
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Disentangling structural brain alterations associated with violent behavior from those associated with substance use disorders.
Arch. Gen. Psychiatry
PUBLISHED: 06-06-2011
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Studies aimed at identifying structural brain alterations associated with persistent violent behavior or psychopathy have not adequately accounted for a lifetime history of substance misuse. Thus, alterations in gray matter (GM) volume that have been reported to be correlates of violent behavior and/or psychopathy may instead be related to lifelong substance use disorders (SUDs).
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Polymeric complements to the Alzheimers disease biomarker ?-amyloid isoforms A?1-40 and A?1-42 for blood serum analysis under denaturing conditions.
J. Am. Chem. Soc.
PUBLISHED: 06-01-2011
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Treatment of Alzheimers disease (AD) is plagued by a lack of practical and reliable methods allowing early diagnosis of the disease. We here demonstrate that robust receptors prepared by molecular imprinting successfully address current limitations of biologically derived receptors in displaying affinity for hydrophobic peptide biomarkers for AD under denaturing conditions. C-terminal epitope-imprinted polymers showing enhanced binding affinity for A?1-42 were first identified from a 96-polymer combinatorial library. This information was then used to synthesize molecularly imprinted polymers for both of the ?-amyloid (A?) isoforms and a corresponding nonimprinted polymer. A solid-phase extraction method was developed to be compatible with sample loading under conditions of complete protein denaturation. This resulted in a method capable of quantitatively and selectively enriching a shorter C-terminal peptide corresponding to the sequences A?33-40 and A?33-42 as well as the full-length sequence A?1-40 and A?1-42 from a 4 M guanidinum chloride solution. Application of the method to serum allowed selective, high-recovery extraction of both biomarkers at spiking levels marginally higher than clinically relevant concentrations found in cerebrospinal fluid.
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Association of systemic inflammation markers with the presence and extent of coronary artery calcification.
Cytokine
PUBLISHED: 04-04-2011
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Coronary artery calcification (CAC) is a marker for the presence and extent of coronary atherosclerotic plaques and can be detected non-invasively by multi-detector row CT (MDCT). Well known predictors of CAC are age, gender, and the classical atherogenic risk factors. CAC is associated with atherosclerotic plaque burden, but it is still elusive if atherosclerosis-relevant cytokines and chemokines are also associated with CAC.
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Left anterior temporal lobe sustains naming in Alzheimers dementia and mild cognitive impairment.
Curr Alzheimer Res
PUBLISHED: 04-01-2011
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Cognitive decline in degenerative dementia is paralleled by progressive brain atrophy, with the localization of atrophy reflecting specific cognitive impairment. Confrontation naming deficits are frequently observed in dementia across etiologies. In this study we aimed to identify the brain regions underlying this deficit. In patients with clinically diagnosed dementia or mild cognitive impairment (MCI) we investigated the relationship between gray matter volume (GMV) and performance on a standardized confrontation naming test. 268 patients with one of three probable etiologies were included: Alzheimers Dementia (AD), AD with signs of cerebrovascular pathology, and frontotemporal dementia. Applying voxel-based morphometry using a diffeomorphic registration algorithm we contrasted GMV of patients performing within the normal range with those of patients with pathological performance. Further, differential effects of gray matter atrophy on impaired performance in AD versus MCI of AD type were investigated. Results revealed significantly reduced GMV in the left anterior temporal lobe (ATL) in pathological performers compared to normal performers. The subgroup analysis confined to MCI of AD type and AD patients confirmed this relationship. While left ATL atrophy is known to be implicated in naming deficits in semantic dementia, our data confirm the same in AD and MCI of AD type.
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Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimers disease.
Paul Hollingworth, Denise Harold, Rebecca Sims, Amy Gerrish, Jean-Charles Lambert, Minerva M Carrasquillo, Richard Abraham, Marian L Hamshere, Jaspreet Singh Pahwa, Valentina Moskvina, Kimberley Dowzell, Nicola Jones, Alexandra Stretton, Charlene Thomas, Alex Richards, Dobril Ivanov, Caroline Widdowson, Jade Chapman, Simon Lovestone, John Powell, Petroula Proitsi, Michelle K Lupton, Carol Brayne, David C Rubinsztein, Michael Gill, Brian Lawlor, Aoibhinn Lynch, Kristelle S Brown, Peter A Passmore, David Craig, Bernadette McGuinness, Stephen Todd, Clive Holmes, David Mann, A David Smith, Helen Beaumont, Donald Warden, Gordon Wilcock, Seth Love, Patrick G Kehoe, Nigel M Hooper, Emma R L C Vardy, John Hardy, Simon Mead, Nick C Fox, Martin Rossor, John Collinge, Wolfgang Maier, Frank Jessen, Eckart Rüther, Britta Schürmann, Reiner Heun, Heike Kölsch, Hendrik van den Bussche, Isabella Heuser, Johannes Kornhuber, Jens Wiltfang, Martin Dichgans, Lutz Frölich, Harald Hampel, John Gallacher, Michael Hüll, Dan Rujescu, Ina Giegling, Alison M Goate, John S K Kauwe, Carlos Cruchaga, Petra Nowotny, John C Morris, Kevin Mayo, Kristel Sleegers, Karolien Bettens, Sebastiaan Engelborghs, Peter P De Deyn, Christine Van Broeckhoven, Gill Livingston, Nicholas J Bass, Hugh Gurling, Andrew McQuillin, Rhian Gwilliam, Panagiotis Deloukas, Ammar Al-Chalabi, Christopher E Shaw, Magda Tsolaki, Andrew B Singleton, Rita Guerreiro, Thomas W Mühleisen, Markus M Nöthen, Susanne Moebus, Karl-Heinz Jöckel, Norman Klopp, H-Erich Wichmann, V Shane Pankratz, Sigrid B Sando, Jan O Aasly, Maria Barcikowska, Zbigniew K Wszolek, Dennis W Dickson, Neill R Graff-Radford, Ronald C Petersen, , Cornelia M van Duijn, Monique M B Breteler, M Arfan Ikram, Anita L Destefano, Annette L Fitzpatrick, Oscar Lopez, Lenore J Launer, Sudha Seshadri, Claudine Berr, Dominique Campion, Jacques Epelbaum, Jean-Francois Dartigues, Christophe Tzourio, Annick Alpérovitch, Mark Lathrop, Thomas M Feulner, Patricia Friedrich, Caterina Riehle, Michael Krawczak, Stefan Schreiber, Manuel Mayhaus, S Nicolhaus, Stefan Wagenpfeil, Stacy Steinberg, Hreinn Stefansson, Kari Stefansson, Jón Snaedal, Sigurbjorn Bjornsson, Palmi V Jonsson, Vincent Chouraki, Benjamin Genier-Boley, Mikko Hiltunen, Hilkka Soininen, Onofre Combarros, Diana Zelenika, Marc Delepine, María J Bullido, Florence Pasquier, Ignacio Mateo, Ana Frank-García, Elisa Porcellini, Olivier Hanon, Eliecer Coto, Victoria Alvarez, Paolo Bosco, Gabriele Siciliano, Michelangelo Mancuso, Francesco Panza, Vincenzo Solfrizzi, Benedetta Nacmias, Sandro Sorbi, Paola Bossù, Paola Piccardi, Beatrice Arosio, Giorgio Annoni, Davide Seripa, Alberto Pilotto, Elio Scarpini, Daniela Galimberti, Alexis Brice, Didier Hannequin, Federico Licastro, Lesley Jones, Peter A Holmans, Thorlakur Jonsson, Matthias Riemenschneider, Kevin Morgan, Steven G Younkin, Michael J Owen, Michael O'Donovan, Philippe Amouyel, Julie Williams.
Nat. Genet.
PUBLISHED: 03-10-2011
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We sought to identify new susceptibility loci for Alzheimers disease through a staged association study (GERAD+) and by testing suggestive loci reported by the Alzheimers Disease Genetic Consortium (ADGC) in a companion paper. We undertook a combined analysis of four genome-wide association datasets (stage 1) and identified ten newly associated variants with P ? 1 × 10(-5). We tested these variants for association in an independent sample (stage 2). Three SNPs at two loci replicated and showed evidence for association in a further sample (stage 3). Meta-analyses of all data provided compelling evidence that ABCA7 (rs3764650, meta P = 4.5 × 10(-17); including ADGC data, meta P = 5.0 × 10(-21)) and the MS4A gene cluster (rs610932, meta P = 1.8 × 10(-14); including ADGC data, meta P = 1.2 × 10(-16)) are new Alzheimers disease susceptibility loci. We also found independent evidence for association for three loci reported by the ADGC, which, when combined, showed genome-wide significance: CD2AP (GERAD+, P = 8.0 × 10(-4); including ADGC data, meta P = 8.6 × 10(-9)), CD33 (GERAD+, P = 2.2 × 10(-4); including ADGC data, meta P = 1.6 × 10(-9)) and EPHA1 (GERAD+, P = 3.4 × 10(-4); including ADGC data, meta P = 6.0 × 10(-10)).
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Analysis of amyloid-? peptides in cerebrospinal fluid samples by capillary electrophoresis coupled with LIF detection.
Anal. Chem.
PUBLISHED: 02-11-2011
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We report a CE-LIF method for the separation and detection of five synthetic amyloid-? peptides corresponding to an important family of CSF-biomarkers in the context of Alzheimer disease (AD). The presumed most relevant peptides (A?1-42, A?1-40, and A?1-38) that may support the differentiation between AD and healthy patients or other dementias were successfully detected in CSF by incorporating an immunoconcentration step prior to CE analysis of derivatized peptides. We labeled the A? peptides with a fluoroprobe dye before CE-LIF analysis. This reagent reacts with the amino groups of lysine residues and produced mostly ditagged A? peptides under the proposed experimental conditions. The labeling reaction displayed similar efficiency with each one of the five different synthetic A? peptides that were tested. The limit of detection of the CE-LIF method approached 280 attomoles of injected synthetic labeled A? peptides. We obtained excellent correlation between peak areas and peptide concentrations from 35 nM to 750 nM. For the detection of A? peptides in human CSF samples, we enriched the peptides by immunoprecipitation prior to the CE-LIF analysis. The comparison of the CE-LIF profiles obtained from CSF samples from 3 AD patients and 4 non-demented control subjects indicated noticeable differences, suggesting that this method, which relies on a multibiomarker approach, may have potential as a clinical diagnostic test for AD.
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Different CSF ?-amyloid processing in Alzheimers and Creutzfeldt-Jakob disease.
J Neural Transm
PUBLISHED: 01-06-2011
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Decreased levels of ?-amyloid (A?) 1-42 in cerebrospinal fluid (CSF) are characteristic for Alzheimers disease (AD) and are also evident in Creutzfeldt-Jakob disease (CJD). A? plaques are thought to be responsible for this decrease in AD patients, whereas such A? plaques are rarely seen in CJD. To investigate the A? pattern in brain and CSF of neuropathologically confirmed CJD and AD patients we used an electrophoretic method to investigate A? peptide fractions which are not accessible to ELISA and immunohistochemistry. We analyzed A? peptides in the CSF of autopsy-confirmed CJD and AD patients and the corresponding brain homogenates using a quantitative urea-based A? electrophoresis immunoblot (A?-SDS-PAGE/immunoblot).The CSF A?1-42 decrease correlated with the brain A? load in AD, but not in CJD. There was no difference in the soluble fractions of brain homogenate in AD and CJD. We therefore conclude that different mechanisms in AD and CJD are responsible for the A?1-42 decrease in the CSF.
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Structural design, solid-phase synthesis and activity of membrane-anchored ?-secretase inhibitors on A? generation from wild-type and Swedish-mutant APP.
Chemistry
PUBLISHED: 12-07-2010
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Covalent coupling of ?-secretase inhibitors to a raftophilic lipid anchor via a suitable spacer by using solid-phase peptide synthesis leads to tripartite structures displaying substantially improved inhibition of cellular secretion of the ?-amyloid peptide (A?). Herein, we describe a series of novel tripartite structures, their full characterization by NMR spectroscopy and mass spectrometry, and the analysis of their biological activity in cell-based assays. The tripartite structure concept is applicable to different pharmacophores, and the potency in terms of ?-secretase inhibition can be optimized by adjusting the spacer length to achieve an optimal distance of the inhibitor from the lipid bilayer. A tripartite structure containing a transition-state mimic inhibitor was found to be less potent on A? generation from Swedish-mutant amyloid precursor protein (APP) than from the wild-type protein. Moreover, our observations suggest that specific variants of A? are generated from wild-type APP but not from Swedish-mutant APP and are resistant to ?-secretase inhibition. Efficient inhibition of A? secretion by tripartite structures in the absence of appreciable neurotoxicity was confirmed in a primary neuronal cell culture, thus further supporting the concept.
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Cerebrospinal fluid tau, p-tau 181 and amyloid-?38/40/42 in frontotemporal dementias and primary progressive aphasias.
Dement Geriatr Cogn Disord
PUBLISHED: 10-22-2010
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We determined cerebrospinal fluid (CSF) concentrations of amyloid-? (A?)(1-38), A?(1-40), A?(1-42), total tau and phospho-tau (p-tau) in order to study their differential expression in frontotemporal dementia (FTD, n = 25) and primary progressive aphasia (PPA, n = 12) as compared to Alzheimers dementia (AD, n = 25) and nondemented controls (n = 20).
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Retrieval of the Alzheimers amyloid precursor protein from the endosome to the TGN is S655 phosphorylation state-dependent and retromer-mediated.
Mol Neurodegener
PUBLISHED: 10-11-2010
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Retrograde transport of several transmembrane proteins from endosomes to the trans-Golgi network (TGN) occurs via Rab 5-containing endosomes, mediated by clathrin and the recently characterized retromer complex. This complex and one of its putative sorting receptor components, SorLA, were reported to be associated to late onset Alzheimers disease (AD). The pathogenesis of this neurodegenerative disorder is still elusive, although accumulation of amyloidogenic Abeta is a hallmark. This peptide is generated from the sucessive ?- and ?- secretase proteolysis of the Alzheimers amyloid precursor protein (APP), events which are associated with endocytic pathway compartments. Therefore, APP targeting and time of residence in endosomes would be predicted to modulate Abeta levels. However, the formation of an APP- and retromer-containing protein complex with potential functions in retrieval of APP from the endosome to the TGN had, to date, not been demonstrated directly. Further, the motif(s) in APP that regulate its sorting to the TGN have not been characterized.
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A method to prevent cross contamination during 2-DE by ?-amyloid peptides.
Proteomics
PUBLISHED: 09-10-2010
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A method for the efficient decontamination of aluminium oxide ceramic 2-DE focusing trays from ?-amyloid peptides (A?) is reported. As these contaminations were resistant to the standard cleaning procedures, additional harsh cleaning steps were necessary for their efficient removal. Our observations suggest that specific surface properties affect the degree of adsorption of the A?-peptides. "Surface catalysed amyloid aggregation" in the aluminium oxide ceramic trays is proposed as a possible underlying mechanism for the occurrence of proteinase K-resistant forms of A?.
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Phagocytosis and LPS alter the maturation state of ?-amyloid precursor protein and induce different A? peptide release signatures in human mononuclear phagocytes.
J Neuroinflammation
PUBLISHED: 08-31-2010
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The classic neuritic ?-amyloid plaque of Alzheimers disease (AD) is typically associated with activated microglia and neuroinflammation. Similarly, cerebrovascular ?-amyloid (A?) deposits are surrounded by perivascular macrophages. Both observations indicate a contribution of the mononuclear phagocyte system to the development of ?-amyloid.
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Microchip electrophoresis profiling of A? peptides in the cerebrospinal fluid of patients with Alzheimers disease.
Anal. Chem.
PUBLISHED: 08-21-2010
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The preferential aggregation of A?1-42 in amyloid plaques is one of the major neuropathological events in Alzheimers disease. This is accompanied by a relative reduction of the concentration of A?1-42 in the cerebrospinal fluid (CSF) of patients developing the signs of Alzheimers disease. Here, we describe a microchip gel electrophoresis method in polydimethylsiloxane (PDMS) chip that enables rapid profiling of major A? peptides in cerebrospinal fluid. To control the electroosmotic flow (EOF) in the PDMS channel and also to reduce the adsorption of the peptides to the surface of the channel, a new double coating using poly(dimethylacrylamide-co-allyl glycidyl ether) (PDMA-AGE) and methylcellulose-Tween-20 was developed. With this method, separation of five synthetic A? peptides (A?1-37, A?1-38, A?1-39, A?1-40, and A?1-42) was achieved, and relative abundance of A?1-42 to A?1-37 could be calculated in different standard mixtures. We applied our method for profiling of A? peptides in CSF samples from nonAlzheimer patients and patients with Alzheimers disease. A? peptides in the CSF samples were captured and concentrated using a microfluidic system in which magnetic beads coated with anti-A? were self-organized into an affinity microcolumn under the a permanent magnetic field. Finally, we could detect two A? peptides (A?1-40 and A?1-42) in the CSF samples.
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Impulsivity-related brain volume deficits in schizophrenia-addiction comorbidity.
Brain
PUBLISHED: 07-20-2010
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Despite a high prevalence of schizophrenia patients with comorbid substance abuse, little is known about possible impacts on the brain. Hence, our goal was to determine whether addicted and non-addicted schizophrenic patients suffer from different brain deficits. We were especially interested to determine if grey matter volumes were affected by impulsivity. We hypothesized that (comorbid) substance abuse would be associated with enhanced impulsivity and that this enhanced impulsivity would be related to grey matter volume deficits in prefrontal areas. We employed a voxel-based morphometry approach as well as neuropsychological assessment of executive functions and trait impulsivity in 51 participants (age range 23-55). The schizophrenia group comprised 24 patients (12 patients with paranoid schizophrenia and 12 with additional comorbid substance use disorders). The comparison group comprised 27 non-schizophrenic individuals, matched by age and education (14 healthy individuals and 13 patients with substance use disorders). Total grey matter volume deficits were found in all patient groups as compared with healthy controls but were largest (~8%) in both addicted groups. While grey matter volume losses in lateral orbitofrontal and temporal regions were affected by schizophrenia, volume decreases of the medial orbitofrontal, anterior cingulate and frontopolar cortex were associated with addiction. Compared with non-addicted schizophrenics, comorbid patients showed significant volume decreases in anterior cingulate, frontopolar and superior parietal regions. Additionally, they showed an increased non-planning impulsivity that was negatively related to grey matter volumes in the same regions, except for parietal ones. The present study indicates severe grey matter volume and functional executive deficits in schizophrenia, which were only partially exacerbated by comorbid addiction. However, the relationship between non-planning impulsivity and anterior cingulate and frontopolar grey matter volumes points to a specific structure-function relationship that seems to be impaired in schizophrenia-addiction comorbidity.
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Pre-aggregated A?1-42 peptide increases tau aggregation and hyperphosphorylation after short-term application.
Mol. Cell. Biochem.
PUBLISHED: 06-28-2010
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Neuritic amyloid plaques and neurofibrillary tangles, consisting of hyperphosphorylated tau protein, are the hallmarks of Alzheimer disease. It is not clear so far, how both structures are functionally and physiologically connected. We have investigated the role of A?1-42 on hyperphosphorylation and aggregation of tau in SY5Y cells by transfection and overexpression with two tau constructs, a shortened wildtype tau (2N4R) and a point mutation tau (P301L), found in fronto-temporal dementia. It was found that the tau protein becomes hyperphosphorylated and forms large aggregates inside cells, visualized by immunofluorescence, after short incubation of 90 min with preaggregated A?1-42. In Addition, A?1-42 caused a decrease of tau solubility in both tau constructs in this relatively short time period. Taken together, these experiments suggest that pathological preaggregated A?1-42 in physiological concentrations quickly induces hyperphosphorylation and pathological structural changes of tau protein and thereby directly linking the amyloid hypothesis to tau pathology, observed in Alzheimer disease.
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Methylphenidate-induced psychosis in adult attention-deficit/hyperactivity disorder: report of 3 new cases and review of the literature.
Clin Neuropharmacol
PUBLISHED: 06-24-2010
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We present 3 new cases of psychotic symptoms in patients with adult attention-deficit/hyperactivity disorder while regularly treated with a stimulant therapy with methylphenidate.
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Genetic evidence implicates the immune system and cholesterol metabolism in the aetiology of Alzheimers disease.
PLoS ONE
PUBLISHED: 06-23-2010
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Late Onset Alzheimers disease (LOAD) is the leading cause of dementia. Recent large genome-wide association studies (GWAS) identified the first strongly supported LOAD susceptibility genes since the discovery of the involvement of APOE in the early 1990s. We have now exploited these GWAS datasets to uncover key LOAD pathophysiological processes.
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Confirmation rate of blinded (99m)Tc-SPECT compared to neurochemical dementia biomarkers in CSF in patients with Alzheimer disease.
J Neural Transm
PUBLISHED: 06-01-2010
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In Alzheimer disease, CSF biomarkers and nuclear imaging are of particular interest. Many studies investigated only one technique, limiting comparison. Here, in 76 patients blinded 99mTc-SPECT was compared to CSF. Sensitivity of CSF was 92%; and 51% for SPECT. Specificity favored SPECT (90 vs. 80%). Both techniques showed no coherence (p = 0.17-0.47). Our results confirm that CSF biomarkers show higher sensitivity. SPECT has higher specificity and can also be used for other dementias without established CSF biomarkers.
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A quantitative CE method to analyse tau protein isoforms using coated fused silica capillaries.
J Sep Sci
PUBLISHED: 02-27-2010
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We evaluated the potential of CE to analyse different isoforms of unphosphorylated recombinant tau protein and for separating one phosphorylated tau from the respective unphosphorylated protein. Different capillary coatings such as polyacrylamide, poly-(ethylene oxide) and polybrene (PB) were evaluated to overcome the poor efficiencies obtained with fused-silica capillary. Although peak asymmetry values were quite similar for the three investigated coatings, the peak efficiencies were 35-fold and 5-fold higher with PB coating than with polyacrylamide and poly(ethylene oxide) coatings, respectively. The recovery percentage (over 97%) was satisfactory and confirmed the efficacy of PB coating to limit the adsorption of tau protein to capillary walls. Moreover, PB coating produced higher repeatability for migration times (RSD values <1.2%) in comparison to the neutral coatings. The potential of PB-modified capillary in producing high resolutive separations of one phosphorylated tau isoform from its unphosphorylated counterpart and of a mixture of phosphorylated and unphosphorylated tau peptides was demonstrated with 50 mM phosphate buffer pH 3.0. The separation of unphosphorylated tau isoform 352 (Tau-352) from Tau-352 phosphorylated in vitro by the mitogen-activated protein kinase ERK2, was accomplished in less than 15 min.
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Multicentre variability of MRI-based medial temporal lobe volumetry in Alzheimers disease.
Psychiatry Res
PUBLISHED: 02-16-2010
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Magnetic resonance imaging (MRI)-based volumetry of medial temporal lobe regions is among the best established biomarker candidates of Alzheimers disease (AD) to date. This study assessed the effect of multicentre variability of MRI-based hippocampus and amygdala volumetry on the discrimination between patients with Alzheimers disease (AD) and mild cognitive impairment (MCI) and on the association of morphological changes with ApoE4 genotype and cognition. We studied 113 patients with clinically probable AD and 150 patients with amnestic MCI using high-resolution MRI scans obtained at 12 clinical sites. We determined effect sizes of group discrimination and random effects linear models, considering multicentre variability. Hippocampus and amygdala volumes were significantly reduced in AD compared with MCI patients using data pooled across centres. Multicentre variability did not significantly affect the power to detect a volume difference between AD and MCI patients. Among cognitive measures, delayed recall of verbal and non-verbal material was significantly correlated with hippocampus and amygdala volumes. Amygdala and hippocampus volumes were not associated with ApoE4 genotype in AD or MCI. Our data indicate that multicentre acquisition of MRI data using manual volumetry is reliable and feasible for cross-sectional diagnostic studies, and they replicate essential findings from smaller scale monocentre studies.
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An open trial of gabapentin in acute alcohol withdrawal using an oral loading protocol.
Alcohol Alcohol.
PUBLISHED: 12-17-2009
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Anticonvulsants are increasingly being advocated for the treatment of acute alcohol withdrawal syndrome (AWS) to avoid the addictive properties of established medications. Because earlier works showed that moderate gabapentin doses were too low to clearly ameliorate severe AWS, we tested a higher gabapentin entry dose.
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Modulatory effects of neuropsychopharmaca on intracellular pH of hippocampal neurones in vitro.
Br. J. Pharmacol.
PUBLISHED: 12-10-2009
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The intracellular pH (pHi) of neurones is tightly regulated by, for example, membrane-bound acid-exchangers and loaders. Nevertheless, excessive bioelectric activity lowers steady-state pHi. In turn, even a moderate acidification can inhibit neuronal activity, a process believed to be part of a negative feedback loop controlling neuronal excitation. As moclobemide, an antidepressant, and also some antiepileptic drugs can reduce neuronal pHi in hippocampus slices in vitro, we screened a panel of currently used neuropsychopharmaca for comparable effects.
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Toward a Successful Clinical Neuroproteomics The 11th HUPO Brain Proteome Project Workshop 3 March, 2009, Kolymbari, Greece.
Proteomics Clin Appl
PUBLISHED: 05-20-2009
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The HUPO Brain Proteome Project (HUPO BPP) held its 11th workshop in Kolymbari on March 3, 2009. The principal aim of this project is to obtain a better understanding of neurodiseases and ageing, with the ultimate objective of discovering prognostic and diagnostic biomarkers, in addition to the development of novel diagnostic techniques and new medications. The attendees came together to discuss sub-project progress in the clinical neuroproteomics of human or mouse models of Alzheimers and Parkinsons disease, and to define the needs and guidelines required for more advanced proteomics approaches. With the election of new steering committees, the members of the HUPO BPP elaborated an actual plan promoting activities, outcomes, and future directions of the HUPO BPP to acquire new funding and new participants.
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Neurochemical dementia diagnostics: a simple algorithm for interpretation of the CSF biomarkers.
J Neural Transm
PUBLISHED: 04-29-2009
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Cerebrospinal fluid (CSF)-based neurochemical dementia diagnostics (NDD) is a well-established diagnostic tool for neurodegenerative disorders, including Alzheimers disease (AD). However, the direct comparison of the concentrations of the biomarkers between laboratories is often very misleading, due to relatively high inter-laboratory discrepancies of normal/abnormal ranges (cutoff values). Therefore, an interpretation tool might be useful for centers performing NDD to facilitate a standardized, diagnostic-oriented reporting of the data on biomarkers. In this study, we present a simple, easy-to-implement algorithm allowing diagnostic-relevant categorization of patients according to the outcome of the CSF NDD results and, correspondingly, enabling reporting of the data to clinicians in a clear and easy-to-follow form. The algorithm is flexible and cutoff values independent, meaning each laboratory can easily supplement it with the cutoff values and normal/abnormal ranges according to the needs; the only prerequisite is to perform the standard CSF NDD assays (amyloid beta peptides and Tau/pTau).
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Genome-wide association study identifies variants at CLU and PICALM associated with Alzheimers disease.
Nat. Genet.
PUBLISHED: 04-28-2009
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We undertook a two-stage genome-wide association study (GWAS) of Alzheimers disease (AD) involving over 16,000 individuals, the most powerful AD GWAS to date. In stage 1 (3,941 cases and 7,848 controls), we replicated the established association with the apolipoprotein E (APOE) locus (most significant SNP, rs2075650, P = 1.8 x 10(-157)) and observed genome-wide significant association with SNPs at two loci not previously associated with the disease: at the CLU (also known as APOJ) gene (rs11136000, P = 1.4 x 10(-9)) and 5 to the PICALM gene (rs3851179, P = 1.9 x 10(-8)). These associations were replicated in stage 2 (2,023 cases and 2,340 controls), producing compelling evidence for association with Alzheimers disease in the combined dataset (rs11136000, P = 8.5 x 10(-10), odds ratio = 0.86; rs3851179, P = 1.3 x 10(-9), odds ratio = 0.86).
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Distinct fractional Abeta release patterns in human mononuclear phagocytes.
J. Neuroimmunol.
PUBLISHED: 04-03-2009
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The presence of cells of the mononuclear phagocyte lineage surrounding neuritic and vascular beta-amyloid (Abeta) plaques is a hallmark of Alzheimers disease (AD) neuropathology. The fractional Abeta peptide patterns released by human mononuclear phagocyte (MNP), lymphocyte and PBMC cultures were assessed by Abeta-SDS-PAGE/immunoblot and compared with the Abeta patterns in neuronal supernatants, in cerebrospinal fluid (CSF), and plasma. MNP released substantial amounts of Abeta peptides and the Abeta pattern contrasted with that in neuronal supernatants, CSF and plasma by reduced Abeta(1-42) and increased proportions of N-truncated Abeta species. MNP derived from early AD patients released significantly more total Abeta peptides than age-matched controls. The proportion of Abeta(1-42) was not altered.
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Early and differential diagnosis of dementia and mild cognitive impairment: design and cohort baseline characteristics of the German Dementia Competence Network.
Dement Geriatr Cogn Disord
PUBLISHED: 04-01-2009
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The German Dementia Competence Network (DCN) has established procedures for standardized multicenter acquisition of clinical, biological and imaging data, for centralized data management, and for the evaluation of new treatments.
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gamma-Secretase heterogeneity in the Aph1 subunit: relevance for Alzheimers disease.
Science
PUBLISHED: 03-19-2009
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The gamma-secretase complex plays a role in Alzheimers disease and cancer progression. The development of clinically useful inhibitors, however, is complicated by the role of the gamma-secretase complex in regulated intramembrane proteolysis of Notch and other essential proteins. Different gamma-secretase complexes containing different Presenilin or Aph1 protein subunits are present in various tissues. Here we show that these complexes have heterogeneous biochemical and physiological properties. Specific inactivation of the Aph1B gamma-secretase in a mouse Alzheimers disease model led to improvements of Alzheimers disease-relevant phenotypic features without any Notch-related side effects. The Aph1B complex contributes to total gamma-secretase activity in the human brain, and thus specific targeting of Aph1B-containing gamma-secretase complexes may help generate less toxic therapies for Alzheimers disease.
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Treatment effects of serotonergic and noradrenergic antidepressants on the intensity dependence of auditory ERP components in major depression.
Neurosci. Lett.
PUBLISHED: 03-16-2009
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The intensity dependent amplitude change of auditory evoked potentials (IDAP), an assumed indicator of the level of central nervous serotonergic neurotransmission, was measured in major depressive disorder (MDD, DSM-IV: 296.2, 296.3; APA 1994) before and after treatment with either a selective serotonin reuptake inhibitor or a selective noradrenaline reuptake inhibitor antidepressant and compared with the results of a healthy control group. Auditory evoked P1, N1, P2, P1/N1 and N1/P2 peak-to-peak amplitudes were evaluated in 26 in-patients with MDD prior to and after antidepressant treatment with citalopram (24 days, n=14) or reboxetine (25 days, n=12), and in 43 healthy control subjects. Clinical symptoms of MDD were assessed by means of standardized psychiatric rating scales (CGI, HDRS, HAMA and BDI). The IDAP within the control group remained stable over 24 days (N1 amplitude slope retest ANOVA p=.79). Neither applied antidepressants nor decrease of HDRS total score during treatment had a significant effect on the IDAP in the patients sample. The conclusion that the IDAP does not reflect the temporary depressive state in MDD is discussed.
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Nonsteroidal anti-inflammatory drugs and ectodomain shedding of the amyloid precursor protein.
Neurodegener Dis
PUBLISHED: 02-14-2009
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Epidemiological studies have suggested that long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with a reduced incidence of Alzheimers disease (AD). Several mechanisms have been proposed to explain these findings including increased shedding of the soluble ectodomain of the amyloid precursor protein (sAPP), which functions as a neurotrophic and neuroprotective factor in vitroand in vivo.
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Quantification of amyloid-beta 40 in cerebrospinal fluid.
J. Immunol. Methods
PUBLISHED: 01-28-2009
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Truncated forms and full-length forms of the amyloid-beta 40 (Abeta40) are key molecules in the pathogenesis of dementia, and are detectable in CSF. Reliable methods to detect these biomarkers in CSF are of great importance for understanding the disease mechanisms and for diagnostic purposes.
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Molecular properties of psychopharmacological drugs determining non-competitive inhibition of 5-HT3A receptors.
Eur J Med Chem
PUBLISHED: 01-16-2009
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We developed a structure-property-activity relationship (SPAR)-model for psychopharmacological drugs acting as non-competitive 5-HT(3A) receptor antagonists by using a decision-tree learner provided by the RapidMiner machine learning tool. A single molecular descriptor, namely the molecular dipole moment per molecular weight (mu/MW), predicts whether or not a substance non-competitively antagonizes 5-HT-induced Na(+) currents. A low mu/MW is compatible with drug-cumulation in apolar lipid rafts. This study confirms that size-intensive descriptors allow the development of compact SPAR models.
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Association of SORL1 gene variants with Alzheimers disease.
Brain Res.
PUBLISHED: 01-14-2009
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SORL1 gene variants were described as risk factor of Alzheimers disease (AD) additionally SORL1 gene variants were associated with altered Abeta(42) CSF levels in AD patients. In the present study we investigated the association of SORL1 gene variants (rs2070045 (SNP19), SORL1-18ex26 (SNP21), rs3824968 (SNP23), rs1010159 (SNP25)) with AD risk by using Cox proportional hazard model and Kaplan-Meier survival analysis in 349 AD patients and 483 controls, recruited from a multicenter study of the German Competence Network Dementias. The SNP21G-allele and a SORL1 haplotype consisting of the SNP19 T-allele, SNP21 G-allele and SNP23 A-allele (T/G/A) were associated with increased hazard ratios and an earlier age at onset of AD (SNP21: p=0.002; T/G/A haplotype: p=0.007). This effect was most pronounced in carriers of an additional APOE4 allele (SNP21: p=0.003; T/G/A haplotype: p=0.005). In conclusion, we found SORL1 gene variants located in the 3 region of the gene to be associated with increased AD risk and an earlier age at onset of AD in our Central-European population. Thus, our data support a role of SORL1 polymorphisms in AD.
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Combined CSF tau, p-tau181 and amyloid-beta 38/40/42 for diagnosing Alzheimers disease.
J Neural Transm
PUBLISHED: 01-14-2009
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Cerebrospinal fluid (CSF) concentrations of amyloid-beta (Abeta) 1-38, 1-40, 1-42, total-tau and phospho-tau in samples from 156 patients with Alzheimers disease (AD) (n = 44), depressive cognitive complainers (DCC, n = 25) and various other forms of non-Alzheimer dementias (NAD, n = 87) were analyzed by electrochemiluminescence and enzyme linked immunosorbent assay, respectively. A significant decrease of CSF Abeta1-42 was the most powerful single marker for differentiation of AD from DCC, yielding accuracies of beyond 85%. Increased p-tau and the ratio Abeta1-42/Abeta1-38 yielded accuracies of beyond 80 and 85%, respectively, to discriminate AD versus NAD. Combining p-tau with Abeta1-42/Abeta1-38 resulted in a sensitivity of 94% for detection of AD and 85% specificity for excluding NAD. Decreased CSF Abeta1-42 represents a core biomarker for AD. The lack of specificity for exclusion of NAD can be most effectively compensated by the ratio Abeta1-42/Abeta1-38. The ratio Abeta1-42/Abeta1-38/p-tau powerfully discriminates AD versus NAD and fulfils the accuracy requirements for an applicable screening and differential diagnostic AD biomarker.
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Theory of mind and empathy in patients at an early stage of relapsing remitting multiple sclerosis.
Clin Neurol Neurosurg
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Early after having been diagnosed with relapsing remitting multiple sclerosis (RRMS), young patients coping with the new situation require good social support and interactions. Successful social interaction is critically dependent upon the ability to understand the minds of others and their feelings. Social cognition refers to the ability to understand the mind of others. Theory of mind (ToM) defines the capability to reason about mental states of others. Empathy describes the ability to have insight into emotional stages and feelings of others. Despite the knowledge of cognitive impairment, which can have profound effects on patients daily activities and quality of life in advanced stages of multiple sclerosis, little is known concerning social cognition in early stages of RRMS.
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Differential sialylation of serpin A1 in the early diagnosis of Parkinsons disease dementia.
PLoS ONE
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The prevalence of Parkinsons disease (PD) increases with age. Up to 50% of PD show cognitive decline in terms of a mild cognitive impairment already in early stages that predict the development of dementia, which can occur in up to 80% of PD patients over the long term, called Parkinsons disease dementia (PDD). So far, diagnosis of PD/PDD is made according to clinical and neuropsychological examinations while laboratory data is only used for exclusion of other diseases. The aim of this study was the identification of possible biomarkers in cerebrospinal fluid (CSF) of PD, PDD and controls (CON) which predict the development of dementia in PD. For this, a proteomic approach optimized for CSF was performed using 18 clinically well characterized patients in a first step with subsequent validation using 84 patients. Here, we detected differentially sialylated isoforms of Serpin A1 as marker for differentiation of PD versus PDD in CSF. Performing 2D-immunoblots, all PDD patients could be identified correctly (sensitivity 100%). Ten out of 24 PD patients showed Serpin A1 isoforms in a similar pattern like PDD, indicating a specificity of 58% for the test-procedure. In control samples, no additional isoform was detected. On the basis of these results, we conclude that differentially sialylated products of Serpin A1 are an interesting biomarker to indicate the development of a dementia during the course of PD.
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Neurochemical biomarkers in Alzheimers disease and related disorders.
Ther Adv Neurol Disord
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Neurochemical biomarkers for diagnosing dementias are currently under intensive investigation and the field is rapidly expanding. The main protagonists and the best defined among them are cerebrospinal fluid levels of A?42, tau and its phosphorylated forms (p-tau). In addition, novel cerebrospinal fluid biomarkers are emerging and their multiparametric assessment seems most promising for increasing the accuracy in neurochemical dementia diagnostics. The combined assessment of A?42 and p-tau has recently shown value for diagnosing prodromal states of Alzheimers dementia, that is, mild cognitive impairment. Disease-specific biomarkers for other degenerative dementias are still missing, but some progress has recently been made. As lumbar puncture is an additional burden for the patient, blood-based neurochemical biomarkers are definitely warranted and promising new discoveries have been made in this direction. These diagnostic developments have implicit therapeutic consequences and give rise to new requirements for future neurochemical dementia diagnostics.
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Perception of affective prosody in patients at an early stage of relapsing-remitting multiple sclerosis.
J Neuropsychol
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Cognitive dysfunction is well known in patients suffering from multiple sclerosis (MS) and has been described for many years. Cognitive impairment, memory, and attention deficits seem to be features of advanced MS stages, whereas depression and emotional instability already occur in early stages of the disease. However, little is known about processing of affective prosody in patients in early stages of relapsing-remitting MS (RRMS). In this study, tests assessing attention, memory, and processing of affective prosody were administered to 25 adult patients with a diagnosis of RRMS at an early stage and to 25 healthy controls (HC). Early stages of the disease were defined as being diagnosed with RRMS in the last 2 years and having an Expanded Disability Status Scale (EDSS) of 2 or lower. Patients and HC were comparable in intelligence quotient (IQ), educational level, age, handedness, and gender. Patients with early stages of RRMS performed below the control group with respect to the subtests discrimination of affective prosody and matching of affective prosody to facial expression for the emotion angry of the Tübingen Affect Battery. These deficits were not related to executive performance. Our findings suggest that emotional prosody comprehension is deficient in young patients with early stages of RRMS. Deficits in discriminating affective prosody early in the disease may make misunderstandings and poor communication more likely. This might negatively influence interpersonal relationships and quality of life in patients with RRMS.
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Structural brain alterations associated with schizophrenia preceded by conduct disorder: a common and distinct subtype of schizophrenia?
Schizophr Bull
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Conduct disorder (CD) prior to age 15 is a precursor of schizophrenia in a minority of cases and is associated with violent behavior through adulthood, after taking account of substance misuse. The present study used structural magnetic imaging to examine gray matter (GM) volumes among 27 men with schizophrenia preceded by CD (SZ+CD), 23 men with schizophrenia but without CD (SZ-CD), 27 men with CD only (CD), and 25 healthy (H) men. The groups with schizophrenia were similar in terms of age of onset and duration of illness, levels of psychotic symptoms, and medication. The 2 groups with CD were similar as to number of CD symptoms, lifelong aggressive behavior, and number of criminal convictions. Men with SZ+CD, relative to those with SZ-CD, displayed (1) increased GM volumes in the hypothalamus, the left putamen, the right cuneus/precuneus, and the right inferior parietal cortex after controlling for age, alcohol, and drug misuse and (2) decreased GM volumes in the inferior frontal region. Men with SZ+CD (relative to the SZ-CD group) and CD (relative to the H group) displayed increased GM volumes of the hypothalamus and the inferior and superior parietal lobes, which were not associated with substance misuse. Aggressive behavior, both prior to age 15 and lifetime tendency, was positively correlated with the GM volume of the hypothalamus. Thus, among males, SZ+CD represents a distinct subtype of schizophrenia. Although differences in behavior emerge in childhood and remain stable through adulthood, further research is needed to determine whether the differences in GM volumes result from abnormal neural development distinct from that of other males developing schizophrenia.
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New pathways of increased cardiovascular risk in depression: a pilot study on the association of high-sensitivity C-reactive protein with pro-atherosclerotic markers in patients with depression.
J Affect Disord
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An elevation of inflammatory markers such as high-sensitivity C-reactive protein (hs-CRP) can be found in patients with depressive disorders. Inflammatory processes are known to influence atherosclerosis and might also mediate the link between depression and diabetes. The present study aimed at comparing hs-CRP and its relationship with atherogenic platelet markers in patients with type 2 diabetes (TD2) and/or newly diagnosed major depression (MD).
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Optimisation of BACE1 inhibition of tripartite structures by modification of membrane anchors, spacers and pharmacophores - development of potential agents for the treatment of Alzheimers disease.
Org. Biomol. Chem.
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Systematic variation of membrane anchor, spacer and pharmacophore building blocks leads to an optimisation of the inhibitory effect of tripartite structures towards BACE1-induced cleavage of the amyloid precursor protein (APP).
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Plasma amyloid-beta peptides in acute cerebral ischemia: a pilot study.
J. Clin. Lab. Anal.
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Blood-based tests for a rapid and valid diagnosis as well as outcome prognosis of acute stroke are desirable. Recently, plasma A?40 was suggested as an independent cerebrovascular risk factor candidate.
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Development of a magnetic immunosorbent for on-chip preconcentration of amyloid ? isoforms: Representatives of Alzheimers disease biomarkers.
Biomicrofluidics
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Determination of amyloid ? (A?) isoforms and in particular the proportion of the A? 1-42 isoform in cerebrospinal fluid (CSF) of patients suspected of Alzheimers disease might help in early diagnosis and treatment of that illness. Due to the low concentration of A? peptides in biological fluids, a preconcentration step prior to the detection step is often necessary. This study utilized on-chip immunoprecipitation, known as micro-immunoprecipitation (?IP). The technique uses an immunosorbent (IS) consisting of magnetic beads coated with specific anti-A? antibodies organized into an affinity microcolumn by a magnetic field. Our goal was to thoroughly describe the critical steps in developing the IS, such as selecting the proper beads and anti-A? antibodies, as well as optimizing the immobilization technique and ?IP protocol. The latter includes selecting optimal elution conditions. Furthermore, we demonstrate the efficiency of anti-A? IS for ?IP and specific capture of 5 A? peptides under optimized conditions using various subsequent analytical methods, including matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), capillary electrophoresis, microchip electrophoresis, and immunoblotting. Synthetic A? peptides samples prepared in buffer and spiked in human CSF were analyzed. Finally, on-chip immunoprecipitation of A? peptides in human CSF sample was performed.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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