| 1. |
- Londos, Elisabet, et al.
(författare)
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Extreme sleep pattern in Lewy body dementia : A hypothalamic matter?
- 2019
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Ingår i: BMJ Case Reports. - : BMJ. - 1757-790X. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- Excessive sleep during the night and for >2 hours during the day is part of the fluctuating wakefulness criterion of dementia with Lewy bodies (DLB). The phenomenon â € sleep days' is not uncommon in nursing homes. Here, we describe a woman who, for months, slept for 3 days and nights in a row and thereafter was awake for 3 days and nights. Electroencephalogram (EEG) showed slow background activity and increased delta activity. No epileptiform activity was detected. Polysomnography showed a severely disturbed, markedly fragmented sleep pattern. On her death, neuropathology revealed degeneration and loss of neurons along with α-synuclein-containing Lewy body inclusions and neurites in the substantia nigra, locus coeruleus, hypothalamus, and neocortex, thus fulfilling the criteria of DLB, cortical type. We propose that the hypothalamic degeneration contributed significantly to the clinical profile in this case. We suggest that patients with sleep days should be investigated for other DLB signs.
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| 2. |
- Lampinen, Björn, et al.
(författare)
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Searching for the neurite density with diffusion MRI : Challenges for biophysical modeling
- 2019
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Ingår i: Human Brain Mapping. - : Wiley. - 1065-9471 .- 1097-0193. ; 40:8, s. 2529-2545
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Tidskriftsartikel (refereegranskat)abstract
- In vivo mapping of the neurite density with diffusion MRI (dMRI) is a high but challenging aim. First, it is unknown whether all neurites exhibit completely anisotropic (“stick-like”) diffusion. Second, the “density” of tissue components may be confounded by non-diffusion properties such as T2 relaxation. Third, the domain of validity for the estimated parameters to serve as indices of neurite density is incompletely explored. We investigated these challenges by acquiring data with “b-tensor encoding” and multiple echo times in brain regions with low orientation coherence and in white matter lesions. Results showed that microscopic anisotropy from b-tensor data is associated with myelinated axons but not with dendrites. Furthermore, b-tensor data together with data acquired for multiple echo times showed that unbiased density estimates in white matter lesions require data-driven estimates of compartment-specific T2 values. Finally, the “stick” fractions of different biophysical models could generally not serve as neurite density indices across the healthy brain and white matter lesions, where outcomes of comparisons depended on the choice of constraints. In particular, constraining compartment-specific T2 values was ambiguous in the healthy brain and had a large impact on estimated values. In summary, estimating neurite density generally requires accounting for different diffusion and/or T2 properties between axons and dendrites. Constrained “index” parameters could be valid within limited domains that should be delineated by future studies.
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| 3. |
- Nilholm, Clara, et al.
(författare)
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Dietary intervention with an Okinawan-based Nordic diet in type 2 diabetes renders decreased interleukin-18 concentrations and increased neurofilament light concentrations in plasma
- 2018
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Ingår i: Nutrition Research. - : Elsevier BV. - 0271-5317. ; 60, s. 13-25
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Tidskriftsartikel (refereegranskat)abstract
- Food may induce inflammation and favor development of metabolic diseases, which have been associated with increased inflammation and potential risk of cognitive impairment. It is customary to know whether food or disease promote inflammation. Our hypothesis was that Okinawan-based Nordic (O-BN) diet leads to decreased circulating concentrations of inflammatory and neural biomarkers. The objectives of this study were to examine the effects of the O-BN diet on inflammatory and neural responses. First, 2 different breakfasts; one standard and another O-BN-based, were given in random order to 19 healthy volunteers. Second, a 12-week O-BN-dietary intervention was performed in type 2 diabetes mellitus (T2DM), where the participants were followed for another 16-weeks, with registration of anthropometry and metabolic parameters. Non-diabetic subjects served as controls at baseline. Plasma was analyzed for cytokines by a 10-plex Luminex assay and neurofilament light (NfL) by an ultrasensitive Single molecule assay. Cytokine levels decreased after a single breakfast intake, independent of diet composition. Cytokine levels were higher in T2DM than in controls. Anthropometric and metabolic parameters were improved by the dietary intervention. In parallel, cytokine levels were lowered, although only significantly for IL-18 (P =.001), with a tendency of significance for IL-12p70 (P =.07). Levels of IL-18 correlated with glucose, HbA1c and lipids, but not with body mass index, insulin or blood pressure. NfL levels increased during the intervention (P =.049). O-BN-based diet does not affect postprandial cytokine levels in health, whereas it renders decreased circulating IL-18 levels along with metabolic biomarkers in T2DM, with no beneficial effect on NfL.
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| 4. |
- Smith, Ruben, et al.
(författare)
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18F-AV-1451 tau PET imaging correlates strongly with tau neuropathology in MAPT mutation carriers
- 2016
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 139:9, s. 2372-2379
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Tidskriftsartikel (refereegranskat)abstract
- Tau positron emission tomography ligands provide the novel possibility to image tau pathologyin vivo. However, little is known about howin vivo brain uptake of tau positron emission tomography ligands relates to tau aggregates observed post-mortem. We performed tau positron emission tomography imaging with F-18-AV-1451 in three patients harbouring a p.R406W mutation in theMAPT gene, encoding tau. This mutation results in 3- and 4-repeat tau aggregates similar to those in Alzheimer's disease, and many of the mutation carriers initially suffer from memory impairment and temporal lobe atrophy. Two patients with short disease duration and isolated memory impairment exhibited F-18-AV-1451 uptake mainly in the hippocampus and adjacent temporal lobe regions, correlating with glucose hypometabolism in corresponding regions. One patient died after 26 years of disease duration with dementia and behavioural deficits. Pre-mortem, there was F-18-AV-1451 uptake in the temporal and frontal lobes, as well as in the basal ganglia, which strongly correlated with the regional extent and amount of tau pathology in post-mortem brain sections. Amyloid-beta (F-18-flutemetamol) positron emission tomography scans were negative in all cases, as were stainings of brain sections for amyloid. This provides strong evidence that F-18-AV-1451 positron emission tomography can be used to accurately quantifyin vivo the regional distribution of hyperphosphorylated tau protein.
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| 5. |
- Smith, Ruben, et al.
(författare)
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18F-AV1451 pet detects tau pathology in mapt mutation carriers and correlates strongly with immunohistochemistry of tau aggregates
- 2016
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5279 .- 1552-5260. ; 12:7 Suppl, s. 723-724
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Konferensbidrag (refereegranskat)abstract
- Background: The Tau PET ligand 18F-AV1451 has been shown to reliably detect paired helical filaments of tau in Alzheimer's disease, but it is not yet known whether it binds to the tau aggregates present in patients with mutations in the gene (MAPT) coding for the tau protein. Further, no study has yet compared the cerebral retention of 18F -AV1451 with the tau aggregates revealed using neuropathology. Methods: Three patients from a Swedish family carrying the R406W mutation of MAPT were assessed with cognitive tests and subjects underwent 18F-AV1451 and 18F-Flutemetamol PET scans. Further one of younger subjects also underwent an 18F-FDG PET scan. The oldest subject died two weeks after the scan and the brain was processed for neuropathology. Tau immunohistochemistry was performed on brain sections from affected and unaffected brain regions. Results: Two mutation carriers, aged 56 and 60 years, had disease durations of 5-10 years and still only exhibited mild-moderate episodic memory impairment and no clear behavioural deficits. The MRI revealed only slight cortical atrophy and 18F-AV1451 PET imaging showed uptake in the hippocampus and the temporal lobes, especially in the inferior and anterior parts (Fig 1A, B). The uptake of 18F - AV1451 correlated well with hypometabolism revealed with FGD PET in one of the subjects. The third case, 76 years, had a disease duration of ≥20 years and exhibited clear cognitive impairment, behavioural disturbances, mutism and dysphagia. The CT scan showed generalised cortical atrophy with a pronounced temporal lobe atrophy and 18F -AV1451 PET imaging revealed uptake in the temporal and frontal lobes, as well as in the basal ganglia (Fig 1 C). The regional uptake of 18F -AV1451 correlated strongly with the tau aggregates revealed using immunohistochemistry (R2 = 0.80, P <0.01; Fig 2). All cases exhibited negative amyloid (18F -flutemetamol) PET scans. Conclusions: The in vivo uptake of 18F-AV1451 reflects the regional amount of tau aggregates revealed by neuropathological examination. Further, tau pathology in MAPT mutation carriers is accurately detected with 18F -AV1451 PET, which consequently can be used to track the effects of anti-tau therapies in this patient group. (Figure Presented) .
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| 6. |
- Smith, Ruben, et al.
(författare)
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Correlation of in Vivo [18F]Flortaucipir with Postmortem Alzheimer Disease Tau Pathology
- 2019
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149. ; 76:3, s. 310-310
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Tidskriftsartikel (refereegranskat)abstract
- Importance: In Alzheimer disease (AD), tau filaments form neuronal inclusions in neurites (neuropil threads) and in somata (neurofibrillary tangles), and neurite tau pathology constitutes the most common pathology. Positron emission tomography (PET) ligands have been developed to detect in vivo tau pathology in AD. However, the association of AD tau pathology post mortem with in vivo tau PET retention has not been established. Therefore, there is a need to investigate the associations of tau PET with postmortem tau pathology in AD. Objective: To study the association of regional in vivo retention of the tau PET ligand [18F]flortaucipir (previously known as AV1451) with the density of tau neuropathology in the corresponding brain regions in a patient with AD. Design, Setting, and Participants: The patient was a man in his 40s with AD caused by a PSEN1 mutation. Between May 2015 and December 2016, he underwent 2 [18F]flortaucipir PET scans at Lund University Hospital, Lund, Sweden. Postmortem analysis was performed 12 months after the last PET scan. Tau pathology was assessed using phosphorylated tau (AT8) immunohistochemistry and Gallyas silver staining. In addition to the regional total tau pathology burden, the density of tau-positive neurites and intrasomal tau tangles were quantified using a stereology-based method. Further, β-amyloid-containing plaques were detected using 4G8 immunohistochemistry. Data were analyzed between January 2018 and August 2018. Main Outcomes and Measures: Regional standardized uptake value ratios of [18F]flortaucipir were compared with the amount of tau pathology in the corresponding brain areas. Results: In this patient, the clinical disease symptoms progressed rapidly in life, paralleled with an annual increase of tau PET retention of 20% to 40% in many cortical regions. Compared with postmortem immunohistochemistry, regional in vivo uptake of [18F]flortaucipir was correlated with the density of tau-positive neurites (AT8: rs = 0.87; P <.001; Gallyas: rs = 0.92; P <.001), intrasomal tau tangles (AT8: rs = 0.65; P =.01; Gallyas: rs = 0.84; P <.001), and total tau burden (AT8: rs = 0.84; P <.001; Gallyas: rs = 0.82; P <.001). No correlations between [18F]flortaucipir and β-amyloid pathology were found. Conclusions and Relevance: These results indicate that [18F]flortaucipir PET retention is a robust in vivo measure of the total AD tau burden.
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| 7. |
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| 8. |
- Ygland, Emil, et al.
(författare)
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Slowly progressive dementia caused by MAPT R406W mutations : longitudinal report on a new kindred and systematic review
- 2018
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Ingår i: Alzheimer's Research & Therapy. - : BioMed Central. - 1758-9193. ; 10
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Forskningsöversikt (refereegranskat)abstract
- Background: The MAPT c.1216C > T (p.Arg406Trp; R406W) mutation is a known cause of frontotemporal dementia with Parkinsonism linked to chromosome 17 tau with Alzheimer's disease-like clinical features. Methods: We compiled clinical data from a new Swedish kindred with R406W mutation. Seven family members were followed longitudinally for up to 22 years. Radiological examinations were performed in six family members and neuropathological examinations in three. We systematically reviewed the literature and compiled clinical, radiological, and neuropathological data on 63 previously described R406W heterozygotes and 3 homozygotes. Results: For all cases combined, the median age of onset was 56 years and the median disease duration was 13 years. Memory impairment was the most frequent symptom, behavioral disturbance and language impairment were less common, and Parkinsonism was rare. Disease progression was most often slow. The most frequent clinical diagnosis was Alzheimer's disease. R406W homozygotes had an earlier age at onset and a higher frequency of behavioral symptoms and Parkinsonism than heterozygotes. In the new Swedish kindred, a consistent imaging finding was ventromedial temporal lobe atrophy, which was evident also in early disease stages as a widening of the collateral sulcus with ensuing atrophy of the parahippocampal gyrus. Unlike previously published R406W carriers, all three autopsied patients from the novel family showed neuropathological similarities with progressive supranuclear palsy, with predominant four-repeat (exon 10+) tau isoform (4R) tauopathy and neurofibrillary tangles accentuated in the basal-medial temporal lobe. Amyloid-beta pathology was absent. Conclusions: Dominance of 4R over three-repeat (exon 10-) tau isoforms contrasts with earlier reports of R406W patients and was not sufficiently explained by the presence of H1/H2 haplotypes in two of the autopsied patients. R406W patients often show a long course of disease with marked memory deficits. Both our neuropathological results and our imaging findings revealed that the ventromedial temporal lobes were extensively affected in the disease. We suggest that this area may represent the point of origin of tau deposition in this disease with relatively isolated tauopathy.
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