| 1. |
- Fernandez, J. L. Abelleira, et al.
(författare)
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A Large Hadron Electron Collider at CERN
- 2012
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Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 39:7
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Kruse, N., et al.
(författare)
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Validation of a quantitative cerebrospinal fluid alpha-synuclein assay in a European-wide interlaboratory study
- 2015
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580. ; 36:9, s. 2587-2596
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Tidskriftsartikel (refereegranskat)abstract
- Decreased levels of alpha-synuclein (aSyn) in cerebrospinal fluid (CSF) in Parkinson's disease and related synucleinopathies have been reported, however, not consistently in all cross-sectional studies. To test the performance of one recently released human-specific enzyme-linked immunosorbent assay (ELISA) for the quantification of aSyn in CSF, we carried out a round robin trial with 18 participating laboratories trained in CSF ELISA analyses within the BIOMARKAPD project in the EU Joint Program -Neurodegenerative Disease Research. CSF samples (homogeneous aliquots from pools) and ELISA kits (one lot) were provided centrally and data reported back to one laboratory for data analysis. Our study showed that although factors such as preanalytical sample handling and lot-to-lot variability were minimized by our study design, we identified high variation in absolute values of CSF aSyn even when the same samples and same lots of assays were applied. We further demonstrate that although absolute concentrations differ between laboratories the quantitative results are comparable. With further standardization this assay may become an attractive tool for comparing aSyn measurements in diverse settings. Recommendations for further validation experiments and improvement of the interlaboratory results obtained are given. (C) 2015 Elsevier Inc. All rights reserved.
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| 3. |
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| 6. |
- Willemse, E. A. J., et al.
(författare)
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Pre-analytical stability of novel cerebrospinal fluid biomarkers
- 2019
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Ingår i: Clinica Chimica Acta. - : Elsevier BV. - 0009-8981. ; 497, s. 204-211
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Tidskriftsartikel (refereegranskat)abstract
- Stability of the cerebrospinal fluid (CSF) composition under different pre-analytical conditions is relevant for the diagnostic potential of biomarkers. Our aim was to examine the pre-analytical stability of promising CSF biomarkers that are currently evaluated for their discriminative use in various neurological diseases. Pooled CSF was aliquoted and experimentally exposed to delayed storage: 0, 1, 2, 4, 24, 72, or 168 h at 4 °C or room temperature (RT), or 1–4 months at −20 °C; or up to 7 freeze/thaw (f/t) cycles, before final storage at −80 °C. Eleven CSF biomarkers were screened using immunoassays, liquid chromatography, or enzymatic methods. Levels of neurogranin (truncP75), chitinase-3-like protein (YKL-40), beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), acetylcholinesterase (AChE) enzymatic activity, theobromine, secreted protein acidic and rich in cysteine-like 1 (SPARCL-1) and homovanillic acid (HVA) levels were not affected by the applied storage conditions. 3-Methoxy-4-hydroxyphenylglycol (MHPG) levels linearly and strongly decreased after 4 h at RT (−10%) or 24 h at 4 °C (−27%), and with 6% after every f/t cycle. 5-Methyltetrahydrofolate (5-MTHF) (−29% after 1 week at RT) and 5-hydroxyindoleacetic acid levels (5-HIAA) (−16% after 1 week at RT) were reduced and 3,4-dihydroxyphenylacetic acid (DOPAC) levels (+22% after 1 week at RT) increased, but only after >24 h at RT. Ten out of eleven potential CSF novel biomarkers showed very limited change under common storage and f/t conditions, suggesting that these CSF biomarkers can be trustfully tested under the pre-analytical conditions present across different cohorts. © 2019 Elsevier B.V.
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| 8. |
- Andreasen, N, et al.
(författare)
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Cerebrospinal fluid tau and Abeta42 as predictors of development of Alzheimer's disease in patients with mild cognitive impairment
- 1999
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Ingår i: Neuroscience Letters. - 0304-3940. ; 273:1, s. 5-8
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Tidskriftsartikel (refereegranskat)abstract
- We studied CSF-tau and CSF-Abeta42 in 16 patients with mild cognitive impairment (MCI) who at follow-up investigations 6-27 months later had progressed to Alzheimer's disease (AD) with dementia. For comparison, we studied 15 age-matched healthy individuals. At baseline, 14/16 (88%) of MCI patients had high CSF-tau and/or low CSF-Abeta42 levels. These findings show that these CSF-markers are abnormal before the onset of clinical dementia and that they may help to identify MCI patients that will develop AD. This is especially important when drugs with potential effects on the progression of AD will reach the clinical phase.
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| 11. |
- Andreasen, N, et al.
(författare)
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Evaluation of CSF-tau and CSF-Abeta42 as diagnostic markers for Alzheimer disease in clinical practice
- 2001
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Ingår i: Archives of Neurology. - 0003-9942. ; 58:3, s. 373-379
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To evaluate the diagnostic potential of cerebrospinal fluid (CSF) levels of tau and beta-amyloid protein ending at amino acid 42 (Abeta42) as biomarkers for Alzheimer disease (AD) in clinical practice. DESIGN: A 1-year prospective study. SETTING: Community population-based sample of all consecutive patients admitted for investigation of cognitive symptoms to the Pitea River Valley Hospital, Pitea, Sweden. PATIENTS: A total of 241 patients with probable AD (n = 105), possible AD (n = 58), vascular dementia (n = 23), mild cognitive impairment (n = 20), Lewy body dementia (n = 9), other neurological disorders (n = 3), and psychiatric disorders (n = 5) and nondemented individuals (n = 18). MAIN OUTCOME MEASURES: Cerebrospinal fluid tau and CSF-Abeta42 were assayed each week as routine clinical neurochemical analyses. Sensitivity and specificity were defined using the regression line from 100 control subjects from a multicenter study. Positive and negative predictive values were calculated for different prevalence rates of AD. RESULTS: We found increased CSF-tau and decreased CSF-Abeta42 levels in probable and possible AD. Sensitivity was 94% for probable AD, 88% for possible AD, and 75% for mild cognitive impairment, whereas specificity was 100% for psychiatric disorders and 89% for nondemented. Specificity was lower in Lewy body dementia (67%) mainly because of low CSF-Abeta42 levels and in vascular dementia (48%) mainly because of high CSF-tau levels. Sensitivity for CSF-tau and CSF-Abeta42 increased in patients with AD possessing the ApoE epsilon4 allele, approaching 100%. At a prevalence of AD of 45%, the positive predictive value was 90% and the negative predictive value was 95%. CONCLUSIONS: Cerebrospinal fluid tau and CSF-Abeta42 have so far been studied in research settings, under conditions providing data on the optimal performance. We examined a prospective patient sample, with assays run in clinical routine, giving figures closer to the true performance of CSF-tau and CSF-Abeta42. The predictive value for AD was greater than 90%. Therefore, these biomarkers may have a role in the clinical workup of patients with cognitive impairment, especially to differentiate early AD from normal aging and psychiatric disorders.
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| 12. |
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| 13. |
- Andreasen, N, et al.
(författare)
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Sensitivity, specificity, and stability of CSF-tau in AD in a community-based patient sample
- 1999
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Ingår i: Neurology. - 1526-632X. ; 53:7, s. 1488-1488
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To evaluate the sensitivity and specificity of CSF-tau in clinical practice as a diagnostic marker for AD compared with normal aging and depression, to study the stability of CSF-tau in longitudinal samples, and to determine whether CSF-tau levels are influenced by different covariates such as gender, age, duration or severity of disease, or possession of the APOE-epsilon4 allele. METHODS: Consecutive AD patients from a community-based sample were studied, including 407 patients with AD (274 with probable AD and 133 with possible AD), 28 patients with depression, and 65 healthy elderly control subjects. A follow-up lumbar puncture was performed in 192 AD patients after approximately 1 year. CSF-tau was determined using a sandwich ELISA, which was run as a routine clinical neurochemical analysis. RESULTS: CSF-tau was increased in probable (690+/-341 pg/mL; p < 0.0001) and possible (661+/-447 pg/mL; p < 0.0001) AD, but not in depression (231+/-110 pg/mL) compared with control subjects (227+/-101 pg/mL). Receiver operating characteristics analysis showed that a cutoff level of 302 pg/mL resulted in a sensitivity of 93% (95% CI, 90-96%) and a specificity of 86% (95% CI, 75-94%), with an area under the curve of 0.95 to discriminate AD from control subjects. Within the AD group, CSF-tau did not differ significantly between baseline and follow-up investigations, and was relatively stable between baseline and 1-year follow-up levels, with a coefficient of variation of 21.0%. High CSF-tau levels were also found in most AD patients with very short duration of dementia, and with Mini-Mental State Examination scores >23 (n = 205). In total, 193 of 205 patients (sensitivity, 94%) had a CSF-tau level higher than 302 pg/mL. CONCLUSIONS: CSF-tau has a high sensitivity and specificity to differentiate AD from normal aging and depression, as demonstrated in a large community-based series of consecutive AD patients during which analyses were run continually in a clinical neurochemical laboratory. The increase in CSF-tau is found very early in the disease process in AD, is stable over time, and has a low interindividual variation on repeated sampling. Although high CSF-tau is found in some neurologic conditions (e.g., stroke), these findings suggest that CSF-tau may be of use to help in differentiating AD from normal aging and depression, especially early in the course of the disease, when the symptoms are vague and the diagnosis is especially difficult.
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| 14. |
- Hampel, H., et al.
(författare)
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beta-Secretase1 biological markers for Alzheimer's disease: state-of-art of validation and qualification
- 2020
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- beta -Secretase1 (BACE1) protein concentrations and rates of enzyme activity, analyzed in human bodily fluids, are promising candidate biological markers for guidance in clinical trials investigating BACE1 inhibitors to halt or delay the dysregulation of the amyloid-beta pathway in Alzheimer's disease (AD). A robust body of evidence demonstrates an association between cerebrospinal fluid/blood BACE1 biomarkers and core pathophysiological mechanisms of AD, such as brain protein misfolding and aggregration, neurodegeneration, and synaptic dysfunction.In pharmacological trials, BACE1 candidate biomarkers may be applied to a wide set of contexts of use (CoU), including proof of mechanism, dose-finding, response and toxicity dose estimation. For clinical CoU, BACE1 biomarkers show good performance for prognosis and disease prediction.The roadmap toward validation and qualification of BACE1 biomarkers requires standardized pre-analytical and analytical protocols to reduce inter-site variance that may have contributed to inconsistent results.BACE1 biomarker-drug co-development programs, including biomarker-guided outcomes and endpoints, may support the identification of sub-populations with a higher probability to benefit from BACE1 inhibitors with a reduced risk of adverse effects, in line with the evolving precision medicine paradigm.
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| 15. |
- Vanmechelen, E, et al.
(författare)
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Cerebrospinal fluid tau and beta-amyloid(1-42) in dementia disorders
- 2001
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Ingår i: Mechanisms of Ageing and Development. - 0047-6374. ; 122:16, s. 2005-2011
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Tidskriftsartikel (refereegranskat)abstract
- The reliability of cerebrospinal fluid (CSF)-tau and CSF-beta-amyloid assays for diagnosis of Alzheimer's disease and other dementing disorders such as frontotemporal dementia (FTD), dementia with Lewy bodies (DLB) and Creutzfeldt-Jakob disease (CJD) is reviewed. CSF assessment of the two proteins is useful in early diagnosis of AD and to differentiate it from FTD and DLB. Extremely high CSF-tau levels can discriminate CJD from AD.
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| 16. |
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| 17. |
- Vergallo, A., et al.
(författare)
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Plasma amyloid beta 40/42 ratio predicts cerebral amyloidosis in cognitively normal individuals at risk for Alzheimer's disease
- 2019
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Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 15:6, s. 764-775
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Blood-based biomarkers of pathophysiological brain amyloid beta (A beta) accumulation, particularly for preclinical target and large-scale interventions, are warranted to effectively enrich Alzheimer's disease clinical trials and management. Methods: We investigated whether plasma concentrations of the A beta(1-40)/A beta(1-42) ratio, assessed using the single-molecule array (Simoa) immunoassay, may predict brain A beta positron emission tomography status in a large-scale longitudinal monocentric cohort (N = 276) of older individuals with subjective memory complaints. We performed a hypothesis-driven investigation followed by a no-apriori hypothesis study using machine learning. Results: The receiver operating characteristic curve and machine learning showed a balanced accuracy of 76.5% and 81%, respectively, for the plasma A beta(1-40)/A beta(1-42) ratio. The accuracy is not affected by the apolipoprotein E (APOE) epsilon 4 allele, sex, or age. Discussion: Our results encourage an independent validation cohort study to confirm the indication that the plasma A beta(1-40)/A beta(1-42) ratio, assessed via Simoa, may improve future standard of care and clinical trial design. (C) 2019 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.
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