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Moloney CM, Labuzan SA, Crook JE, Siddiqui H, Castanedes-Casey M, Lachner C, Petersen RC, Duara R, Graff-Radford NR, Dickson DW, Mielke MM, Murray ME. Phosphorylated tau sites that are elevated in Alzheimer's disease fluid biomarkers are visualized in early neurofibrillary tangle maturity levels in the post mortem brain. Alzheimers Dement 2022; 19:10.1002/alz.12749. [PMID: 35920592 PMCID: PMC9895127 DOI: 10.1002/alz.12749] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 05/27/2022] [Accepted: 06/09/2022] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Alzheimer's disease (AD) biomarkers are increasingly more reliable in predicting neuropathology. To facilitate interpretation of phosphorylated tau sites as an early fluid biomarker, we sought to characterize which neurofibrillary tangle maturity levels (pretangle, intermediary 1, mature tangle, intermediary 2, and ghost tangle) are recognized. METHODS We queried the Florida Autopsied Multi-Ethnic (FLAME) cohort for cases ranging from Braak stages I through VI, excluding non-AD neuropathologies and tauopathies. Thioflavin-S staining was compared to immunohistochemical measures of phosphorylated threonine (pT) 181, pT205, pT217, and pT231 in two hippocampal subsectors across n = 24 cases. RESULTS Each phosphorylated tau site immunohistochemically labeled early neurofibrillary tangle maturity levels compared to advanced levels recognized by thioflavin-S. Hippocampal burden generally increased with each Braak stage. DISCUSSION These results provide neurobiologic evidence that these phosphorylated tau fluid biomarker sites are present during early neurofibrillary tangle maturity levels and may explain why these fluid biomarker measures are observed before symptom onset. HIGHLIGHTS Immunohistochemical evaluation of four phosphorylated tau fluid biomarker sites. Earlier neurofibrillary tangle maturity levels recognized by phosphorylated tau in proline-rich region. Advanced tangle pathology is elevated in the subiculum compared to the cornu ammonis 1 of the hippocampus. Novel semi-quantitative frequency to calculate tangle maturity frequency.
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Affiliation(s)
| | | | - Julia E. Crook
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL, USA
| | - Habeeba Siddiqui
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL, USA
| | | | - Christian Lachner
- Division of Psychiatry, Mayo Clinic, Jacksonville, FL, USA
- Department of Neurology, Mayo Clinic, Jacksonville, FL, USA
| | | | - Ranjan Duara
- Wien Center for Alzheimer’s Disease and Memory Disorders, Mount Sinai Medical Center, Miami Beach, FL, USA
| | | | | | - Michelle M. Mielke
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
- Division of Epidemiology, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
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Tau as a Biomarker of Neurodegeneration. Int J Mol Sci 2022; 23:ijms23137307. [PMID: 35806324 PMCID: PMC9266883 DOI: 10.3390/ijms23137307] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 06/29/2022] [Accepted: 06/29/2022] [Indexed: 12/13/2022] Open
Abstract
Less than 50 years since tau was first isolated from a porcine brain, its detection in femtolitre concentrations in biological fluids is revolutionizing the diagnosis of neurodegenerative diseases. This review highlights the molecular and technological advances that have catapulted tau from obscurity to the forefront of biomarker diagnostics. Comprehensive updates are provided describing the burgeoning clinical applications of tau as a biomarker of neurodegeneration. For the clinician, tau not only enhances diagnostic accuracy, but holds promise as a predictor of clinical progression, phenotype, and response to drug therapy. For patients living with neurodegenerative disorders, characterization of tau dysregulation could provide much-needed clarity to a notoriously murky diagnostic landscape.
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Abstract
The history of Alzheimer's disease (AD) started in 1907, but we needed to wait until the end of the century to identify the components of pathological hallmarks and genetic subtypes and to formulate the first pathogenic hypothesis. Thanks to biomarkers and new technologies, the concept of AD then rapidly changed from a static view of an amnestic dementia of the presenium to a biological entity that could be clinically manifested as normal cognition or dementia of different types. What is clearly emerging from studies is that AD is heterogeneous in each aspect, such as amyloid composition, tau distribution, relation between amyloid and tau, clinical symptoms, and genetic background, and thus it is probably impossible to explain AD with a single pathological process. The scientific approach to AD suffers from chronological mismatches between clinical, pathological, and technological data, causing difficulty in conceiving diagnostic gold standards and in creating models for drug discovery and screening. A recent mathematical computer-based approach offers the opportunity to study AD in real life and to provide a new point of view and the final missing pieces of the AD puzzle.
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Affiliation(s)
- Camilla Ferrari
- Department of Neuroscience, Psychology, Drug Research, and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Sandro Sorbi
- Department of Neuroscience, Psychology, Drug Research, and Child Health (NEUROFARBA), University of Florence, Florence, Italy.,IRCCS Fondazione Don Carlo Gnocchi, Florence, Italy
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Pawlowski M, Meuth SG, Duning T. Cerebrospinal Fluid Biomarkers in Alzheimer's Disease-From Brain Starch to Bench and Bedside. Diagnostics (Basel) 2017; 7:diagnostics7030042. [PMID: 28703785 PMCID: PMC5617942 DOI: 10.3390/diagnostics7030042] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 06/21/2017] [Accepted: 07/06/2017] [Indexed: 12/13/2022] Open
Abstract
Alzheimer’s disease is the most common cause of dementia. Over the last three decades, research has advanced dramatically and provided a detailed understanding of the molecular events underlying the pathogenesis of Alzheimer’s disease. In parallel, assays for the detection of biomarkers that reflect the typical Alzheimer’s disease-associated pathology have been developed and validated in myriads of clinical studies. Such biomarkers complement clinical diagnosis and improve diagnostic accuracy. The use of biomarkers will become even more important with the advent of disease-modifying therapies. Such therapies will likely be most beneficial when administered early in the disease course. Here, we summarise the development of the core Alzheimer’s disease cerebrospinal fluid biomarkers: amyloid-β and tau. We provide an overview of their role in cellular physiology and Alzheimer’s disease pathology, and embed their development as cerebrospinal fluid biomarkers into the historical context of Alzheimer’s disease research. Finally, we summarise recommendations for their use in clinical practice, and outline perspectives for novel cerebrospinal fluid candidate biomarkers.
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Affiliation(s)
- Matthias Pawlowski
- Department of Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, Münster 48149, Germany.
| | - Sven G Meuth
- Department of Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, Münster 48149, Germany.
| | - Thomas Duning
- Department of Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, Münster 48149, Germany.
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5
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Abstract
In 1975, tau protein was isolated as a microtubule-associated factor from the porcine brain. In the previous year, a paired helical filament (PHF) protein had been identified in neurofibrillary tangles in the brains of individuals with Alzheimer disease (AD), but it was not until 1986 that the PHF protein and tau were discovered to be one and the same. In the AD brain, tau was found to be abnormally hyperphosphorylated, and it inhibited rather than promoted in vitro microtubule assembly. Almost 80 disease-causing exonic missense and intronic silent mutations in the tau gene have been found in familial cases of frontotemporal dementia but, to date, no such mutation has been found in AD. The first phase I clinical trial of an active tau immunization vaccine in patients with AD was recently completed. Assays for tau levels in cerebrospinal fluid and plasma are now available, and tau radiotracers for PET are under development. In this article, we provide an overview of the pivotal discoveries in the tau research field over the past 40 years. We also review the current status of the field, including disease mechanisms and therapeutic approaches.
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Affiliation(s)
- Khalid Iqbal
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Inge Grundke-Iqbal Research Floor, 1050 Forest Hill Road, Staten Island, New York 10314, USA
| | - Fei Liu
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Inge Grundke-Iqbal Research Floor, 1050 Forest Hill Road, Staten Island, New York 10314, USA
| | - Cheng-Xin Gong
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Inge Grundke-Iqbal Research Floor, 1050 Forest Hill Road, Staten Island, New York 10314, USA
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Olsson B, Zetterberg H, Hampel H, Blennow K. Biomarker-based dissection of neurodegenerative diseases. Prog Neurobiol 2011; 95:520-34. [PMID: 21524681 DOI: 10.1016/j.pneurobio.2011.04.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 04/06/2011] [Accepted: 04/10/2011] [Indexed: 12/12/2022]
Abstract
The diagnosis of neurodegenerative diseases within neurology and psychiatry are hampered by the difficulty in getting biopsies and thereby validating the diagnosis by pathological findings. Biomarkers for other types of disease have been readily adopted into the clinical practice where for instance troponins are standard tests when myocardial infarction is suspected. However, the use of biomarkers for neurodegeneration has not been fully incorporated into the clinical routine. With the development of cerebrospinal fluid (CSF) biomarkers that reflect pathological events within the central nervous system (CNS), important clinical diagnostic tools are becoming available. This review summarizes the most promising biomarker candidates that may be used to monitor different types of neurodegeneration and protein inclusions, as well as different types of metabolic changes, in living patients in relation to the clinical phenotype and disease progression over time. Our aim is to provide the reader with an updated lexicon on currently available biomarker candidates, how far they have come in development and how well they reflect pathogenic processes in different neurodegenerative diseases. Biomarkers for specific pathogenetic processes would also be valuable tools both to study disease pathogenesis directly in patients and to identify and monitor the effect of novel treatment strategies.
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Affiliation(s)
- Bob Olsson
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, S-431 80 Mölndal, Sweden.
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Abstract
Alzheimer disease is the most common cause of dementia, yet its clinical diagnosis remains uncertain until an eventual postmortem histopathology examination. Currently, therapy for patients with Alzheimer disease only treats the symptoms; however, it is anticipated that new disease-modifying drugs will soon become available.Diagnostic tools for detecting Alzheimer disease at an incipient stage that can reliably differentiate the disease from other forms of dementia are of key importance for optimal treatment. Biomarkers have the potential to aid in a correct diagnosis, and great progress has been made in the discovery and development of potentially useful biomarkers in recent years. This includes single protein biomarkers in the cerebrospinal fluid, as well as multi-component biomarkers, and biomarkers based on gene expression. Novel biomarkers that use blood and urine, the more easily available clinical samples, are also being discovered and developed. The plethora of potential biomarkers currently being investigated may soon provide biomarkers that fulfill different functions, not only for diagnostic purposes but also for drug development and to follow disease progression.
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Abstract
The introduction of acetylcholine esterase (AChE) inhibitors as a symptomatic treatment of Alzheimer's disease (AD) has made patients seek medical advice at an earlier stage of the disease. This has highlighted the importance of diagnostic markers for early AD. However, there is no clinical method to determine which of the patients with mild cognitive impairment (MCI) will progress to AD with dementia, and which have a benign form of MCI without progression. In this paper, the performance of cerebrospinal fluid (CSF) protein biomarkers for AD is reviewed. The diagnostic performance of the three biomarkers, total tau, phospho-tau, and the 42 amino acid form of beta-amyloid have been evaluated in numerous studies and their ability to identify incipient AD in MCI cases has also been studied. Some candidate AD biomarkers including ubiquitin, neurofilament proteins, growth-associated protein 43 (neuromodulin), and neuronal thread protein (AD7c) show interesting results but have been less extensively studied. It is concluded that CSF biomarkers may have clinical utility in the differentiation between AD and several important differential diagnoses, including normal aging, depression, alcohol dementia, and Parkinson's disease, and also in the identification of Creutzfeldt-Jakob disease in cases with rapidly progressive dementia. Early diagnosis of AD is not only of importance to be able to initiate symptomatic treatment with AChE inhibitors, but will be the basis for initiation of treatment with drugs aimed at slowing down or arresting the degenerative process, such as gamma-secretase inhibitors, if these prove to affect AD pathology and to have a clinical effect.
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Affiliation(s)
- Kaj Blennow
- Department of Clinical Neuroscience, Section of Experimental Neuroscience, The Sahlgrenska Academy at Göteborg University, SE-43180 Göteborg, Sweden.
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Bancher C, Jellinger K, Wichart I. Biological markers for the diagnosis of Alzheimer's disease. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 1998; 53:185-97. [PMID: 9700657 DOI: 10.1007/978-3-7091-6467-9_17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A diagnostic test for Alzheimer's disease (AD) based on biochemical markers in the cerebrospinal fluid can help improve diagnostic accuracy, which currently is approximately 90%, leaving every tenth AD patient undiagnosed or falsely diagnosed as having the disease. From all biochemical abnormalities described in AD patients, those related to the hallmark neuropathologic lesions, deposition of amyloid and formation of paired helical filaments mainly consisting of abnormally phosphorylated tau protein, are the most promising and the best documented, even though other markers bear some potential and remain to be further studied. Determining an increase of tau and a reduction of A beta 42 bears satisfactory, even though not absolute specificity for AD and represents a true aid for clinicians in diagnosing AD during the patients lifetime. It remains open if these markers will be helpful for the most challenging goal, diagnosing AD in the preclinical phase, when, according to morphological data, high amounts of these pathological proteins are already deposited in the brain tissue.
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Affiliation(s)
- C Bancher
- Ludwig Boltzmann Institute of Clinical Neurobiology, Lainz Hospital, Wien, Austria
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Blennow K, Cowburn RF. The neurochemistry of Alzheimer's disease. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 1996; 168:77-86. [PMID: 8997425 DOI: 10.1111/j.1600-0404.1996.tb00378.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The last 15-20 years have seen a wealth of studies to characterize the neurochemical abnormalities of Alzheimer's disease, in particular those involving the beta-amyloid and tau proteins, as well as more recently, apolipoprotein E4. This article provides a summary of the evidence for the involvement of these proteins in Alzheimer's disease pathogenesis based on postmortem brain and CSF studies.
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Affiliation(s)
- K Blennow
- Department of Clinical Neuroscience, University of Göteborg, Mölndal Hospital, Sweden
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Blennow K, Wallin A, Agren H, Spenger C, Siegfried J, Vanmechelen E. Tau protein in cerebrospinal fluid: a biochemical marker for axonal degeneration in Alzheimer disease? MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1995; 26:231-45. [PMID: 8748926 DOI: 10.1007/bf02815140] [Citation(s) in RCA: 526] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cerebrospinal fluid (CSF) biochemical markers for Alzheimer disease (AD) would be of great value to improve the clinical diagnostic accuracy of the disorder. As abnormally phosphorylated forms of the microtubule-associated protein tau have been consistently found in the brains of AD patients, and since tau can be detected in CSF, two assays based on several well-defined monoclonal tau antibodies were used to study these proteins in CSF. One assay detects most normal and abnormal forms of tau (CSF-tau), while the other is highly specific for phosphorylated tau (CSF-PHFtau). A marked increase in CSF-PHFtau was found in AD (2230 +/- 930 pg/mL), as compared with controls (640 +/- 230 pg/mL; p < 0.0001), vascular dementia, VAD (1610 +/- 840 pg/mL; p < 0.05), frontal lobe dementia, FLD (1530 +/- 1000 pg/mL; p < 0.05), Parkinson disease, PD (720 +/- 590 pg/mL; p < 0.0001), and patients with major depression (230 +/- 130 pg/mL; p < 0.0001). Parallel results were obtained for CSF-tau. No less than 35/40 (88%) of AD patients had a CSF-PHFtau value higher than the cutoff level of 1140 pg/mL in controls. The present study demonstrates that elevated tau/PHFtau levels are consistently found in CSF of AD patients. However, a considerable overlap is still present with other forms of dementia, both VAD and FLD. CSF-tau and CSF-PHFtau may therefore be useful as a positive biochemical marker, to discriminate AD from normal aging, PD, and depressive pseudodementia. Further studies are needed to clarify the sensitivity and specificity of these assays, including follow-up studies with neuropathological examinations.
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Affiliation(s)
- K Blennow
- Department of Clinical Neuroscience, University of Göteborg, Sweden
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12
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Abstract
OBJECTIVE To review studies on cerebrospinal fluid (CSF) in patients with Alzheimer's disease (AD) in order to answer the question whether CSF contains a specific marker which can be used to support a clinical diagnosis of AD. DATA SOURCES Studies identified through an English-language literature search using MEDLINE (1966 to 1990) and a review of bibliographies of relevant articles. STUDY SELECTION All studies on CSF in AD patients were selected. Double publications on the same original data were not included. Otherwise, no particular selection was made. DATA EXTRACTION The diagnostic utility of more than 60 substances, including CSF measures related to classical neurotransmitters, (neuro)peptides, proteins, amino acids, purines, trace elements, and constituents of senile plaques and neurofibrillary tangles, is evaluated. Clinical epidemiological criteria for deciding on the usefulness of new diagnostic methods are emphasized in this analysis. DATA SYNTHESIS Concentrations of some CSF constituents are consistently found to be significantly changed in AD. However, overlap with data of control populations and methodological shortcomings in study design, limit the diagnostic value of all CSF measurements reviewed. CONCLUSIONS None of the CSF constituents studied so far can be used in support of the diagnosis of AD. However, increased knowledge concerning macromolecular abnormalities in amyloid containing plaques and neurofibrillary tangles makes the outlook for a diagnostic test for AD on CSF promising.
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Affiliation(s)
- W A van Gool
- Department of Neurology, Academisch Medisch Centrum, Amsterdam, The Netherlands
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Wang GP, Iqbal K, Bucht G, Winblad B, Wisniewski HM, Grundke-Iqbal I. Alzheimer's disease: paired helical filament immunoreactivity in cerebrospinal fluid. Acta Neuropathol 1991; 82:6-12. [PMID: 1659107 DOI: 10.1007/bf00310917] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A competitive enzyme-linked immunosorbent assay with high sensitivity has been developed for measuring ubiquitin reactivity of paired helical filaments (PHF). Using the assay, ubiquitin immunoreactivity was estimated in the cerebrospinal fluid (CSF) of 44 patients who had been clinically diagnosed as having Alzheimer's disease (AD) and of 38 control patients, including 20 neurological cases. Monoclonal antibody (mAb) 5-25 to isolated paired helical filaments was used. This mAb recognizes amino acids 64-76 of ubiquitin. The levels of ubiquitin immunoreactivity measured in CSF (twice diluted) were significantly higher in the AD (p less than 0.001) than in the control group. In only a minority of instances were values for ubiquitin levels the same in AD and control groups: on PHF-coated plates, immunoreactivity values for 77% of the AD CSF specimens were higher than those for 92% of the controls, and on ubiquitin-coated plates, values for 85% of the AD CSF specimens were higher than those for 88% of the controls. On immunoblots of both AD and control CSF, mAb 5-25 stained a series of protein bands. The free ubiquitin that is also present in the CSF was not labeled. No striking differences were detected in the immunoblot pattern of AD and control CSF. This study demonstrates the presence of quantitative differences in the conjugated ubiquitin in AD and control CSF.
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Affiliation(s)
- G P Wang
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314
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Singh VK, Fudenberg HH. Implications of immunomodulant therapy in Alzheimer's disease. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 1988; 32:21-42. [PMID: 3064183 DOI: 10.1007/978-3-0348-9154-7_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Abstract
Monoclonal antibodies raised against cerebrospinal fluid (CSF) and human ventral forebrain from patients with Alzheimer's disease were tested against CSF pools derived from patients with Alzheimer's disease and normal controls. Antibodies that appeared to distinguish the two pools were subsequently tested against 58 CSF samples from individual Alzheimer patients, normal controls, and individuals with other neurologic diseases. The mean CSF content of two antigens was decreased in patients with Alzheimer's disease compared with controls; the mean CSF content of one of these antigens was also decreased in patients with other neurologic diseases. Although group differences could be detected, the degree of overlap did not follow for the separation of individual patients within these three groups.
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Affiliation(s)
- L J Thal
- Department of Neurology, San Diego VA Medical Center, CA 92161
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Wisniewski HM, Iqbal K, Grundke-Iqbal I, Rubenstein R. The solubility controversy of paired helical filaments: a commentary. Neurochem Res 1987; 12:93-5. [PMID: 3574590 DOI: 10.1007/bf00971370] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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