| 1. |
- Visser, P. J., et al.
(författare)
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Development of screening guidelines and clinical criteria for predementia Alzheimer's disease
- 2008
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Ingår i: Neuroepidemiology. - : S. Karger AG. - 1423-0208 .- 0251-5350. ; 30:4, s. 254-265
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is an urgent need to identify subjects with Alzheimer's disease (AD) in the predementia phase, but validated diagnostic approaches are currently lacking. In this paper, we present the background, design and methods of a study, which aims to develop clinical criteria for predementia AD. We also present baseline characteristics of the subjects included. The study was part of the multicentre DESCRIPA project, which is being conducted within the network of the European Alzheimer's Disease Consortium. Methods: Clinical criteria will be based on a prospective cohort study of non-demented subjects older than 55 years and referred to a memory clinic. At baseline, a number of markers and risk factors for AD were collected, including demographic variables, measures of performance in activities of daily living, cognitive, neuroimaging and genetic markers, and serum and cerebrospinal fluid markers. Subjects will be reassessed annually for 2 - 3 years, and we will evaluate which combination of variables best predicts AD-type dementia at follow-up. Results: Between 2003 and 2005, 881 subjects were included from 20 memory clinics. Subjects were on average 70.3 years old, and had 10.4 years of education. The average score on the Mini-Mental State Examination was 27.4.
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| 2. |
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| 3. |
- Clendenning, M, et al.
(författare)
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A frame-shift mutation of PMS2 is a widespread cause of Lynch syndrome
- 2008
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 45:6, s. 340-345
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Tidskriftsartikel (refereegranskat)abstract
- Background: When compared to the other mismatch repair genes involved in Lynch syndrome, the identification of mutations within PMS2 has been limited (<2% of all identified mutations), yet the immunohistochemical analysis of tumour samples indicates that approximately 5% of Lynch syndrome cases are caused by PMS2. This disparity is primarily due to complications in the study of this gene caused by interference from pseudogene sequences. Methods: Using a recently developed method for detecting PMS2 specific mutations, we have screened 99 patients who are likely candidates for PMS2 mutations based on immunohistochemical analysis. Results: We have identified a frequently occurring frame-shift mutation (c.736_741del 6ins11) in 12 ostensibly unrelated Lynch syndrome patients (20% of patients we have identified with a deleterious mutation in PMS2, n = 61). These individuals all display the rare allele (population frequency <0.05) at a single nucleotide polymorphism (SNP) in exon 11, and have been shown to possess a short common haplotype, allowing us to calculate that the mutation arose around 1625 years ago (65 generations; 95% confidence interval 22 to 120). Conclusion: Ancestral analysis indicates that this mutation is enriched in individuals with British and Swedish ancestry. We estimate that there are >10 000 carriers of this mutation in the USA alone. The identification of both the mutation and the common haplotype in one Swedish control sample (n = 225), along with evidence that Lynch syndrome associated cancers are rarer than expected in the probands' families, would suggest that this is a prevalent mutation with reduced penetrance.
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| 4. |
- Clendenning, M, et al.
(författare)
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Long-range PCR facilitates the identification of PMS2-specific mutations
- 2006
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Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794 .- 1098-1004. ; 27:5, s. 490-495
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Tidskriftsartikel (refereegranskat)abstract
- Mutations within the DNA mismatch repair gene, "postmeiotic segregation increased 2" (PMS2), have been associated with a predisposition to hereditary nonpolyposis colorectal cancer (HNPCC; Lynch syndrome). The presence of a large family of highly homologous PMS2 pseudogenes has made previous attempts to sequence PMS2 very difficult. Here, we describe a novel method that utilizes long-range PCR as a way to preferentially amplify PMS2 and not the pseudogenes. A second, exon-specific, amplification from diluted long-range products enables us to obtain a clean sequence that shows no evidence of pseudogene contamination. This method has been used to screen a cohort of patients whose tumors were negative for the PMS2 protein by immunohistochemistry and had not shown any mutations within the MLH1 gene. Sequencing of the PMS2 gene from 30 colorectal and I I endometrial cancer patients identified 10 novel sequence changes as well as 17 sequence changes that had previously been identified. In total, putative pathologic mutations were detected in 11 of the 41 families. Among these were five novel mutations, c.705+1G > T, c.736-741del6ins11, c.862_863del, c.1688G > T, and c.2007-IG > A. We conclude that PMS2 mutation detection in selected Lynch syndrome and Lynch syndrome-like patients is both feasible and desirable.
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| 10. |
- Verwey, N A, et al.
(författare)
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A worldwide multicentre comparison of assays for cerebrospinal fluid biomarkers in Alzheimer's disease.
- 2009
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Ingår i: Annals of clinical biochemistry. - : SAGE Publications. - 0004-5632 .- 1758-1001. ; 46:Pt 3, s. 235-40
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Different cerebrospinal fluid (CSF) amyloid-beta 1-42 (Abeta(1-42)), total Tau (Tau) and Tau phosphorylated at threonine 181 (P-Tau) levels are reported, but currently there is a lack of quality control programmes. The aim of this study was to compare the measurements of these CSF biomarkers, between and within centres. METHODS: Three CSF-pool samples were distributed to 13 laboratories in 2004 and the same samples were again distributed to 18 laboratories in 2008. In 2004 six laboratories measured Abeta(1-42), Tau and P-Tau and seven laboratories measured one or two of these marker(s) by enzyme-linked immunosorbent assays (ELISAs). In 2008, 12 laboratories measured all three markers, three laboratories measured one or two marker(s) by ELISAs and three laboratories measured the markers by Luminex. RESULTS: In 2004, the ELISA intercentre coefficients of variance (interCV) were 31%, 21% and 13% for Abeta(1-42), Tau and P-Tau, respectively. These were 37%, 16% and 15%, respectively, in 2008. When we restricted the analysis to the Innotest (N = 13) for Abeta(1-42), lower interCV were calculated (22%). The centres that participated in both years (N = 9) showed interCVs of 21%, 15% and 9% and intra-centre coefficients (intraCV) of variance of 25%,18% and 7% in 2008. CONCLUSIONS: The highest variability was found for Abeta(1-42). The variabilities for Tau and P-Tau were lower in both years. The centres that participated in both years showed a high intraCV comparable to their interCV, indicating that there is not only a high variation between but also within centres. Besides a uniform standardization of (pre)analytical procedures, the same assay should be used to decrease the inter/intracentre variation.
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| 11. |
- Wiltfang, J., et al.
(författare)
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Consensus Paper of the WFSBP Task Force on Biological Markers of Dementia : The role of CSF and blood analysis in the early and differential diagnosis of dementia
- 2009
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Ingår i: Revista de Psiquiatria Clinica. - 0101-6083. ; 36, s. 1-16
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Forskningsöversikt (refereegranskat)abstract
- Aging of population, and increasing life expectancy result in an increasing number of patients with dementia. This symptom can be a part of a completely curable disease of the central nervous system (e.g, neuroinflammation), or a disease currently considered irreversible (e.g, Alzheimer's disease, AD). In the latter case, several potentially successful treatment approaches are being tested now, demanding reasonable standards of pre-mortem diagnosis. Cerebrospinal fluid and serum analysis (CSF/serum analysis), whereas routinely performed in neuroinflammatory diseases, still requires standardization to be used as an aid to the clinically based diagnosis of AD. Several AD-related CSF parameters (total tau, phosphorylated forms of tau, A beta peptides, ApoE genotype, p97, etc.) tested separately or in a combination provide sensitivity and specificity in the range of 85%, the figure commonly expected from a good diagnostic tool. In this review, recently published reports regarding progress in neurochemical pre-mortem diagnosis of dementias are discussed with a focus on an early and differential diagnosis of AD. Novel perspectives offered by recently introduced technologies, e.g, fluorescence correlation spectroscopy (FCS) and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) are briefly discussed.
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| 12. |
- Wiltfang, J, et al.
(författare)
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Consensus paper of the WFSBP Task Force on Biological Markers of Dementia: the role of CSF and blood analysis in the early and differential diagnosis of dementia.
- 2005
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Ingår i: The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry. - : Informa UK Limited. - 1562-2975. ; 6:2, s. 69-84
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Forskningsöversikt (refereegranskat)abstract
- Aging of population, and increasing life expectancy result in an increasing number of patients with dementia. This symptom can be a part of a completely curable disease of the central nervous system (e.g, neuroinflammation), or a disease currently considered irreversible (e.g, Alzheimer's disease, AD). In the latter case, several potentially successful treatment approaches are being tested now, demanding reasonable standards of pre-mortem diagnosis. Cerebrospinal fluid and serum analysis (CSF/serum analysis), whereas routinely performed in neuroinflammatory diseases, still requires standardization to be used as an aid to the clinically based diagnosis of AD. Several AD-related CSF parameters (total tau, phosphorylated forms of tau, Abeta peptides, ApoE genotype, p97, etc.) tested separately or in a combination provide sensitivity and specificity in the range of 85%, the figure commonly expected from a good diagnostic tool. In this review, recently published reports regarding progress in neurochemical pre-mortem diagnosis of dementias are discussed with a focus on an early and differential diagnosis of AD. Novel perspectives offered by recently introduced technologies, e.g, fluorescence correlation spectroscopy (FCS) and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) are briefly discussed.
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| 13. |
- Buerger, Katharina, et al.
(författare)
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CSF phosphorylated tau protein correlates with neocortical neurofibrillary pathology in Alzheimer's disease.
- 2006
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 129:Pt 11, s. 3035-41
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Tidskriftsartikel (refereegranskat)abstract
- Hyperphosphorylated tau protein (P-tau) in CSF is a core biomarker candidate of Alzheimer's disease. Hyperphosphorylation of tau is thought to lead to neurofibrillary changes, a neuropathological hallmark of this type of dementia. Currently, the question is unresolved whether CSF levels of P-tau reflect neurofibrillary changes within the brain of a patient with the illness. Twenty-six patients were included with intra-vitam CSF as well as post-mortem neuropathological data. In the CSF, P-tau phosphorylated at threonine 231 (P-tau231P) was analysed. Post-mortem, scores of neurofibrillary tangles (NFT) and neuritic plaques (NP) were assessed in frontal, temporal, parietal and hippocampal cortical areas. In the same cortical regions, load of hyperphosphorylated tau protein (HP-tau load) was determined. Concentrations of P-tau231P were measured in frontal cortex homogenates. We found significant correlations between CSF P-tau231P concentrations and scores of NFTs and HP-tau load in all neocortical regions studied. The score of NPs was correlated with CSF P-tau231P only within the frontal cortex. There was a correlation between P-tau231P in CSF and brain homogenates. These findings indicate that CSF P-tau231P may serve as an in vivo surrogate biomarker of neurofibrillary pathology in Alzheimer's disease.
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| 15. |
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| 17. |
- Ewers, Michael, et al.
(författare)
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Increased CSF-BACE 1 activity is associated with ApoE-epsilon 4 genotype in subjects with mild cognitive impairment and Alzheimer's disease.
- 2008
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Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156. ; 131:Pt 5, s. 1252-8
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Tidskriftsartikel (refereegranskat)abstract
- The Apolipoprotein (ApoE) epsilon 4 allele is a major genetic risk factor of Alzheimer's disease, and may affect the production of amyloid beta (A beta(1-42)). Recently, we have shown that beta-secretase (BACE 1) activity can be reliably detected within the brain and human CSF. Here, we have examined an association between the ApoE genotype and CSF-levels of BACE 1 activity in Alzheimer's disease and mild cognitive impairment (MCI). A total of 148 subjects were included: 60 Alzheimer's disease patients, 51 MCI subjects and 37 elderly healthy controls. The CSF-levels of A beta(1-42), BACE 1 activity and BACE protein were measured in all of these subjects. The differences between ApoE-epsilon 4 carriers and ApoE-epsilon 4 non-carriers in these CSF-based measures were determined controlling for gender, age and MMSE score. The ApoE-epsilon 4 genotype was associated with increased BACE 1 activity in both Alzheimer's disease (P = 0.03) and MCI (P = 0.04) subjects. Levels of A beta(1-42) were decreased in ApoE-epsilon 4 carriers in MCI (P = 0.004) but not Alzheimer's disease subjects. This study is the first to demonstrate the association between ApoE-epsilon 4 and CSF-BACE 1 activity in MCI and Alzheimer's disease subjects. The assessment of BACE 1 in CSF may provide a sensitive measure to detect in vivo alterations in the amyloidogenic processing potentially modified by the ApoE genotype.
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| 18. |
- Frisoni, Giovanni B, et al.
(författare)
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The pilot European Alzheimer's Disease Neuroimaging Initiative of the European Alzheimer's Disease Consortium.
- 2008
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 4:4, s. 255-64
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In North America, the Alzheimer's Disease Neuroimaging Initiative (ADNI) has established a platform to track the brain changes of Alzheimer's disease. A pilot study has been carried out in Europe to test the feasibility of the adoption of the ADNI platform (pilot E-ADNI). METHODS: Seven academic sites of the European Alzheimer's Disease Consortium (EADC) enrolled 19 patients with mild cognitive impairment (MCI), 22 with AD, and 18 older healthy persons by using the ADNI clinical and neuropsychological battery. ADNI compliant magnetic resonance imaging (MRI) scans, cerebrospinal fluid, and blood samples were shipped to central repositories. Medial temporal atrophy (MTA) and white matter hyperintensities (WMH) were assessed by a single rater by using visual rating scales. RESULTS: Recruitment rate was 3.5 subjects per month per site. The cognitive, behavioral, and neuropsychological features of the European subjects were very similar to their U.S. counterparts. Three-dimensional T1-weighted MRI sequences were successfully performed on all subjects, and cerebrospinal fluid samples were obtained from 77%, 68%, and 83% of AD patients, MCI patients, and controls, respectively. Mean MTA score showed a significant increase from controls (left, right: 0.4, 0.3) to MCI patients (0.9, 0.8) to AD patients (2.3, 2.0), whereas mean WMH score did not differ among the three diagnostic groups (between 0.7 and 0.9). The distribution of both MRI markers was comparable to matched US-ADNI subjects. CONCLUSIONS: Academic EADC centers can adopt the ADNI platform to enroll MCI and AD patients and older controls with global cognitive and structural imaging features remarkably similar to those of the US-ADNI.
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| 19. |
- Hampel, Harald, et al.
(författare)
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Core candidate neurochemical and imaging biomarkers of Alzheimer's disease.
- 2008
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 4:1, s. 38-48
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: In the earliest clinical stages of Alzheimer's disease (AD) when symptoms are mild, clinical diagnosis can be difficult. AD pathology most likely precedes symptoms. Biomarkers can serve as early diagnostic indicators or as markers of preclinical pathologic change. Candidate biomarkers derived from structural and functional neuroimaging and those measured in cerebrospinal fluid (CSF) and plasma show the greatest promise. Unbiased exploratory approaches, eg, proteomics or cortical thickness analysis, could yield novel biomarkers. The objective of this article was to review recent progress in selected imaging and neurochemical biomarkers for early diagnosis, classification, progression, and prediction of AD. METHODS: We performed a survey of recent research, focusing on core biomarker candidates in AD. RESULTS: A number of in vivo neurochemistry and neuroimaging techniques, which can reliably assess aspects of physiology, pathology, chemistry, and neuroanatomy, hold promise as biomarkers. These neurobiologic measures appear to relate closely to pathophysiologic, neuropathologic, and clinical data, such as hyperphosphorylation of tau, amyloid beta (Abeta) metabolism, lipid peroxidation, pattern and rate of atrophy, loss of neuronal integrity, functional and cognitive decline, as well as risk of future decline. Current advances in the neuroimaging of mediotemporal, neocortical, and subcortical areas of the brain of mild cognitive impairment (MCI) and AD subjects are presented. CSF levels of Abeta42, tau, and hyperphosphorylated tau protein (p-tau) can distinguish subjects with MCI who are likely to progress to AD. They also show preclinical alterations that predict later development of early AD symptoms. Studies on plasma Abeta are not entirely consistent, but recent findings suggest that decreased plasma Abeta42 relative to Abeta40 might increase the risk of AD. Increased production of Abeta in aging is suggested by elevation of BACE1 protein and enzyme activity in the brain and CSF of subjects with MCI. CSF tau and p-tau are increased in MCI as well and show predictive value. Other biomarkers might indicate components of a cascade initiated by Abeta, such as oxidative stress or inflammation. These merit further study in MCI and earlier. CONCLUSIONS: A number of neuroimaging candidate markers are promising, such as hippocampus and entorhinal cortex volumes, basal forebrain nuclei, cortical thickness, deformation-based and voxel-based morphometry, structural and effective connectivity by using diffusion tensor imaging, tractography, and functional magnetic resonance imaging. CSF Abeta42, BACE1, total tau, and p-tau are substantially altered in MCI and clinical AD. Other interesting novel marker candidates derived from blood are being currently proposed (phase I). Biomarker discovery through proteomic approaches requires further research. Large-scale international controlled multicenter trials (such as the U.S., European, Australian, and Japanese Alzheimer's Disease Neuroimaging Initiative and the German Dementia Network) are engaged in phase III development of the core feasible imaging and CSF biomarker candidates in AD. Biomarkers are in the process of implementation as primary outcome variables into regulatory guideline documents regarding study design and approval for compounds claiming disease modification.
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| 20. |
- Pasche, Boris, et al.
(författare)
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Somatic acquisition and signaling of TGFBR1*6A in cancer
- 2005
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Ingår i: Journal of the American Medical Association (JAMA). - : American Medical Association (AMA). - 0098-7484 .- 1538-3598. ; 294:13, s. 1634-1646
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Tidskriftsartikel (refereegranskat)abstract
- Context: TGFBR1*6A is a common polymorphism of the type I transforming growth factor 0 receptor (TGFBR1). Epidemiological studies suggest that TGFBR1*6A may act as a tumor susceptibility allele. How TGFBR1*6A contributes to cancer development is largely unknown.. Objectives: To determine whether TGFBR1*6A is somatically acquired by primary tumors and metastases during cancer development and whether the 3-amino acid deletion that differentiates TGFBR1*6A from TGFBR1 is part of the mature receptor or part of the signal sequence and to investigate TGFBR1*6A signaling in cancer cells. Design, Setting, and Patients: Tumor And germline tissues from 531 patients with a diagnosis of head and neck, colorectal, or breast cancer recruited from 3 centers in the United States and from 1 center in Spain from June 1, 1994, through June 30, 2004, In vitro translation assays, MCF-7 breast cancer cells stably transfected with TGFBR1*6A, TGFBR1, or the vector alone, DLD-1 colorectal cancer cells that endogenously carry TGFBR1*6A, and SW48 colorectal cancer cells that do not carry TGFBR1*6A. Main Outcome Measures: TGFBR1*6A somatic acquisition in cancer. Determination of the amino terminus of the mature TGFBR1*6A and TGFBR1 receptors. Determination of TGF-beta-dependent cell proliferation. Results: TGFBR1*6A was somatically acquired in 13 of 44 (29.5%) colorectal cancer metastases, in 4 of 157 (2.5%) of colorectal tumors, in 4 of 226 (1.8%) head and neck primary tumors, and in none of the 104 patients with breast cancer. TGFBR1*6A somatic acquisition is not associated with loss of heterozygosity, microsatellite instability, or a mutator phenotype. The signal sequences of TGFBR1 and TGFBR1*6A are cleaved at the same site resulting in identical mature receptors. TGFBR1*6A may switch TGF-beta growth inhibitory signals into growth stimulatory signals in MCF-7 breast cancer cells and in DLD-1 colorectal cancer cells. Conclusions: TGFBR1*6A is somatically acquired in 29.5% of liver metastases from colorectal cancer and may bestow cancer cells with a growth advantage in the presence of TGF-beta. The functional consequences of this conversion appear to be mediated by the TGFBR1*6A signal sequence rather than by the mature receptor. The results highlight a new facet of TGF-beta signaling in cancer and suggest that TGFBR1*6A may represent a potential therapeutic target in cancer.
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| 21. |
- van de Pol, L. A., et al.
(författare)
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White matter hyperintensities and medial temporal lobe atrophy in clinical subtypes of mild cognitive impairment: the DESCRIPA study
- 2009
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Ingår i: Journal of Neurology, Neurosurgery and Psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 80:10, s. 1069-1074
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Tidskriftsartikel (refereegranskat)abstract
- Background: Clinical subtypes of mild cognitive impairment (MCI) may represent different underlying aetiologies. Methods: This European, multicentre, memory clinic based study (DESCRIPA) of non-demented subjects investigated whether MCI subtypes have different brain correlates on MRI and whether the relation between subtypes and brain pathology is modified by age. Using visual rating scales, medial temporal lobe atrophy (MTA) (0-4) and white matter hyperintensities (WMH) (0-30) were assessed. Results: Severity of MTA differed between MCI subtypes (p < 0.001), increasing from a mean of 0.8 (SD 0.7) in subjective complaints (n = 77) to 1.3 (0.8) in non-amnestic MCI (n = 93), and from 1.4 (0.9) in single domain amnestic MCI (n = 70) to 1.7 (0.9) in multiple domain amnestic MCI (n = 89). The association between MCI subtype and MTA was modified by age and mainly present in subjects >70 years of age. Severity of WMH did not differ between MCI subtypes (p = 0.21). However, the combination of MTA and WMH differed between MCI subtypes (p = 0.02) Conclusion: We conclude that MCI subtypes may have different brain substrates, especially in older subjects. Isolated MTA was mainly associated with amnestic MCI subtypes, suggesting AD as the underlying cause. In non-amnestic MCI, the relatively higher prevalence of MTA in combination with WMH may suggest a different pathophysiological origin.
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