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| 5. |
- Hooshmand, Babak, et al.
(författare)
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CAIDE Dementia Risk Score, Alzheimer and cerebrovascular pathology : a population-based autopsy study
- 2018
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 283:6, s. 597-603
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Tidskriftsartikel (refereegranskat)abstract
- Background. CAIDE Dementia Risk Score is a tool for estimating dementia risk in the general population. Its longitudinal associations with Alzheimer or vascular neuropathology in the oldest old are not known. Aim. To explore the relationship between CAIDE Dementia Risk Score at baseline and neuritic plaques, neurofibrillary tangles, cerebral infarcts and cerebral amyloid angiopathy (CAA) after up to 10-year follow-up in the Vantaa 85+ population. Methods. Study population included 149 participants aged 85 years, without dementia at baseline, and with available clinical and autopsy data. Methenamine silver staining was used for beta-amyloid and modified Bielschowsky method for neurofibrillary tangles and neuritic plaques. Macroscopic infarcts were identified from cerebral hemispheres, brain-stem and cerebellum slices. Standardized methods were used to determine microscopic infarcts, CAA and alpha-synuclein pathologies. The CAIDE Dementia Risk Score was calculated based on scores for age, sex, BMI, total cholesterol, systolic blood pressure, physical activity and APOE epsilon 4 carrier status (range 0-18 points). Results. A CAIDE Dementia Risk Score above 11 points was associated with more cerebral infarctions up to 10 years later: OR (95% CI) was 2.10 (1.06-4.16). No associations were found with other neuropathologies. Conclusion. In a population of elderly aged 85 years, higher CAIDE Dementia Risk Score was associated with increased risk of cerebral infarcts.
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| 6. |
- Koivunen, J., et al.
(författare)
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PET amyloid ligand [C-11]PIB uptake shows predominantly striatal increase in variant Alzheimer's disease
- 2008
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 131:Pt 7, s. 1845-1853
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Tidskriftsartikel (refereegranskat)abstract
- Variant Alzheimers disease (VarAD) with spastic paraparesis and presenile dementia is associated with certain mutations of the presenilin 1 (PS-1) gene, particularly those leading to deletion of exon 9 (PS-1 E9). VarAD is neuropathologically characterized by the presence of unusually large, A42 positive, non-cored cotton wool plaques (CWPs), also devoid of dystrophic neurites. The aim of the present study was to find out whether [C-11]PIB would show increased uptake and serve as an in vivo biomarker of amyloid accumulation in VarAD. A further aim was to assess the correspondence of the [C-11]PIB binding to the amount and type of A deposits in another group of deceased VarAD patients brains. We studied four patients with VarAD and eight healthy controls with PET using [C-11]PIB as tracer. Parametric images were computed by calculating the region-to-cerebellum and region-to-pons ratio in each voxel over 6090 min. Group differences in [C-11]PIB uptake were analysed with automated region-of-interest (ROI) analysis. [C-11]PIB uptake was compared to the immunohistochemically demonstrated deposition of A in the brains of another group of four deceased VarAD patients. Patients with VarAD had significantly higher [C-11] PIB uptake than the control group in the striatum (caudate nucleus and putamen), anterior and posterior cingulate gyrus, occipital cortex and thalamus. In the caudate and putamen [C-11]PIB uptake, expressed as region-to-cerebellum ratio, was on the average 43 greater than the mean of the control group. The increases in the anterior (28) and posterior (27) cingulate gyrus, occipital cortex (21) and thalamus (14) were smaller. All VarAD patients showed this similar topographical pattern of increased [C-11]PIB uptake. The results were essentially similar when the uptake was expressed as region-to-pons ratios. [C-11]PIB imaging shows increased uptake in patients with VarAD especially in the striatum, and it can be used to detect amyloid accumulation in vivo in these patients. The pattern of increased [C-11]PIB uptake is different from that described in sporadic Alzheimers disease and resembles that seen in Alzheimers disease patients with certain presenilin-1 mutations or amyloid precursor protein gene duplication showing predominantly striatal increase in [C-11]PIB uptake.
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| 7. |
- Körber, R., et al.
(författare)
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SQUIDs in biomagnetism: A roadmap towards improved healthcare
- 2016
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Ingår i: Superconductors Science and Technology. - : IOP Publishing. - 0953-2048 .- 1361-6668. ; 29:11
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Tidskriftsartikel (refereegranskat)abstract
- Globally, the demand for improved health care delivery while managing escalating costs is a major challenge. Measuring the biomagnetic fields that emanate from the human brain already impacts the treatment of epilepsy, brain tumours and other brain disorders. This roadmap explores how superconducting technologies are poised to impact health care. Biomagnetism is the study of magnetic fields of biological origin. Biomagnetic fields are typically very weak, often in the femtotesla range, making their measurement challenging. The earliest in vivo human measurements were made with room-temperature coils. In 1963, Baule and McFee (1963 Am. Heart J. 55 95-6) reported the magnetic field produced by electric currents in the heart ('magnetocardiography'), and in 1968, Cohen (1968 Science 161 784-6) described the magnetic field generated by alpha-rhythm currents in the brain ('magnetoencephalography'). Subsequently, in 1970, Cohen et al (1970 Appl. Phys. Lett. 16 278-80) reported the recording of a magnetocardiogram using a Superconducting QUantum Interference Device (SQUID). Just two years later, in 1972, Cohen (1972 Science 175 664-6) described the use of a SQUID in magnetoencephalography. These last two papers set the scene for applications of SQUIDs in biomagnetism, the subject of this roadmap. The SQUID is a combination of two fundamental properties of superconductors. The first is flux quantization - the fact that the magnetic flux Φ in a closed superconducting loop is quantized in units of the magnetic flux quantum, Φ0 ≡ h/2e, ≈ 2.07 × 10-15 Tm2 (Deaver and Fairbank 1961 Phys. Rev. Lett. 7 43-6, Doll R and Nabauer M 1961 Phys. Rev. Lett. 7 51-2). Here, h is the Planck constant and e the elementary charge. The second property is the Josephson effect, predicted in 1962 by Josephson (1962 Phys. Lett. 1 251-3) and observed by Anderson and Rowell (1963 Phys. Rev. Lett. 10 230-2) in 1963. The Josephson junction consists of two weakly coupled superconductors separated by a tunnel barrier or other weak link. A tiny electric current is able to flow between the superconductors as a supercurrent, without developing a voltage across them. At currents above the 'critical current' (maximum supercurrent), however, a voltage is developed. In 1964, Jaklevic et al (1964 Phys. Rev. Lett. 12 159-60) observed quantum interference between two Josephson junctions connected in series on a superconducting loop, giving birth to the dc SQUID. The essential property of the SQUID is that a steady increase in the magnetic flux threading the loop causes the critical current to oscillate with a period of one flux quantum. In today's SQUIDs, using conventional semiconductor readout electronics, one can typically detect a change in Φ corresponding to 10-6 Φ0 in one second. Although early practical SQUIDs were usually made from bulk superconductors, for example, niobium or Pb-Sn solder blobs, today's devices are invariably made from thin superconducting films patterned with photolithography or even electron lithography. An extensive description of SQUIDs and their applications can be found in the SQUID Handbooks (Clarke and Braginski 2004 Fundamentals and Technology of SQUIDs and SQUID Systems vol I (Weinheim, Germany: Wiley-VCH), Clarke and Braginski 2006 Applications of SQUIDs and SQUID Systems vol II (Weinheim, Germany: Wiley-VCH)). The roadmap begins (chapter 1) with a brief review of the state-of-the-art of SQUID-based magnetometers and gradiometers for biomagnetic measurements. The magnetic field noise referred to the pick-up loop is typically a few fT Hz-1/2, often limited by noise in the metallized thermal insulation of the dewar rather than by intrinsic SQUID noise. The authors describe a pathway to achieve an intrinsic magnetic field noise as low as 0.1 fT Hz-1/2, approximately the Nyquist noise of the human body. They also descibe a technology to defeat dewar noise. Chapter 2 reviews the neuroscientific and clinical use of magnetoencephalography (MEG), by far the most widespread application of biomagnetism with systems containing ty ically 300 sensors cooled to liquid-helium temperature, 4.2 K. Two important clinical applications are presurgical mapping of focal epilepsy and of eloquent cortex in brain-tumor patients. Reducing the sensor-to-brain separation and the system noise level would both improve spatial resolution. The very recent commercial innovation that replaces the need for frequent manual transfer of liquid helium with an automated system that collects and liquefies the gas and transfers the liquid to the dewar will make MEG systems more accessible. A highly promising means of placing the sensors substantially closer to the scalp for MEG is to use high-transition-temperature (high-T c) SQUID sensors and flux transformers (chapter 3). Operation of these devices at liquid-nitrogen temperature, 77 K, enables one to minimize or even omit metallic thermal insulation between the sensors and the dewar. Noise levels of a few fT Hz-1/2 have already been achieved, and lower values are likely. The dewars can be made relatively flexible, and thus able to be placed close to the skull irrespective of the size of the head, potentially providing higher spatial resolution than liquid-helium based systems. The successful realization of a commercial high-T c MEG system would have a major commercial impact. Chapter 4 introduces the concept of SQUID-based ultra-low-field magnetic resonance imaging (ULF MRI) operating at typically several kHz, some four orders of magnitude lower than conventional, clinical MRI machines. Potential advantages of ULF MRI include higher image contrast than for conventional MRI, enabling methodologies not currently available. Examples include screening for cancer without a contrast agent, imaging traumatic brain injury (TBI) and degenerative diseases such as Alzheimer's, and determining the elapsed time since a stroke. The major current problem with ULF MRI is that its signal-to-noise ratio (SNR) is low compared with high-field MRI. Realistic solutions to this problem are proposed, including implementing sensors with a noise level of 0.1 fT Hz-1/2. A logical and exciting prospect (chapter 5) is to combine MEG and ULF MRI into a single system in which both signal sources are detected with the same array of SQUIDs. A prototype system is described. The combination of MEG and ULF MRI allows one to obtain structural images of the head concurrently with the recording of brain activity. Since all MEG images require an MRI to determine source locations underlying the MEG signal, the combined modality would give a precise registration of the two images; the combination of MEG with high-field MRI can produce registration errors as large as 5 mm. The use of multiple sensors for ULF MRI increases both the SNR and the field of view. Chapter 6 describes another potentially far-reaching application of ULF MRI, namely neuronal current imaging (NCI) of the brain. Currently available neuronal imaging techniques include MEG, which is fast but has relatively poor spatial resolution, perhaps 10 mm, and functional MRI (fMRI) which has a millimeter resolution but is slow, on the order of seconds, and furthermore does not directly measure neuronal signals. NCI combines the ability of direct measurement of MEG with the spatial precision of MRI. In essence, the magnetic fields generated by neural currents shift the frequency of the magnetic resonance signal at a location that is imaged by the three-dimensional magnetic field gradients that form the basis of MRI. The currently achieved sensitivity of NCI is not quite sufficient to realize its goal, but it is close. The realization of NCI would represent a revolution in functional brain imaging. Improved techniques for immunoassay are always being sought, and chapter 7 introduces an entirely new topic, magnetic nanoparticles for immunoassay. These particles are bio-funtionalized, for example with a specific antibody which binds to its corresponding antigen, if it is present. Any resulting changes in the properties of the nanoparticles are detected with a SQUID. For liquid-phase detection, there are three ba ic methods: AC susceptibility, magnetic relaxation and remanence measurement. These methods, which have been successfully implemented for both in vivo and ex vivo applications, are highly sensitive and, although further development is required, it appears highly likely that at least some of them will be commercialized. © 2016 IOP Publishing Ltd.
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| 9. |
- Antonios, Gregory, et al.
(författare)
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N-truncated Abeta starting with position four : early intraneuronal accumulation and rescue of toxicity using NT4X-167, a novel monoclonal antibody
- 2013
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 1:1, s. 56-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The amyloid hypothesis in Alzheimer disease (AD) considers amyloid β peptide (Aβ) deposition causative in triggering down-stream events like neurofibrillary tangles, cell loss, vascular damage and memory decline. In the past years N-truncated Aβ peptides especially N-truncated pyroglutamate AβpE3-42 have been extensively studied. Together with full-length Aβ1-42 and Aβ1-40, N-truncated AβpE3-42 and Aβ4-42 are major variants in AD brain. Although Aβ4-42 has been known for a much longer time, there is a lack of studies addressing the question whether AβpE3-42 or Aβ4-42 may precede the other in Alzheimer's disease pathology.RESULTS: Using different Aβ antibodies specific for the different N-termini of N-truncated Aβ, we discovered that Aβ4-x preceded AβpE3-x intraneuronal accumulation in a transgenic mouse model for AD prior to plaque formation. The novel Aβ4-x immunoreactive antibody NT4X-167 detected high molecular weight aggregates derived from N-truncated Aβ species. While NT4X-167 significantly rescued Aβ4-42 toxicity in vitro no beneficial effect was observed against Aβ1-42 or AβpE3-42 toxicity. Phenylalanine at position four of Aβ was imperative for antibody binding, because its replacement with alanine or proline completely prevented binding. Although amyloid plaques were observed using NT4X-167 in 5XFAD transgenic mice, it barely reacted with plaques in the brain of sporadic AD patients and familial cases with the Arctic, Swedish and the presenilin-1 PS1Δ9 mutation. A consistent staining was observed in blood vessels in all AD cases with cerebral amyloid angiopathy. There was no cross-reactivity with other aggregates typical for other common neurodegenerative diseases showing that NT4X-167 staining is specific for AD.CONCLUSIONS: Aβ4-x precedes AβpE3-x in the well accepted 5XFAD AD mouse model underlining the significance of N-truncated species in AD pathology. NT4X-167 therefore is the first antibody reacting with Aβ4-x and represents a novel tool in Alzheimer research.
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| 10. |
- Guzman, Erika Avendano, et al.
(författare)
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Abundance of A beta(5-x) x like immunoreactivity in transgenic 5XFAD, APP/PS1KI and 3xTG mice, sporadic and familial Alzheimer's disease
- 2014
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Ingår i: Molecular Neurodegeneration. - : Springer Science and Business Media LLC. - 1750-1326. ; 9, s. 13-
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Tidskriftsartikel (refereegranskat)abstract
- Background: According to the modified amyloid hypothesis the main event in the pathogenesis of Alzheimer's disease (AD) is the deposition of neurotoxic amyloid beta-peptide (A beta) within neurons. Additionally to full-length peptides, a great diversity of N-truncated A beta variants is derived from the larger amyloid precursor protein (APP). Vast evidence suggests that A beta(x-42) isoforms play an important role triggering neurodegeneration due to its high abundance, amyloidogenic propensity and toxicity. Although N-truncated and A beta(x-42) species have been pointed as crucial players in AD etiology, the A beta(5-x) isoforms have not received much attention. Results: The present study is the first to show immunohistochemical evidence of A beta(5-x) in familial cases of AD (FAD) and its distribution in APP/PS1KI, 5XFAD and 3xTG transgenic mouse models. In order to probe A beta(5-x) peptides we generated the AB5-3 antibody. Positive plaques and congophilic amyloid angiopathy (CAA) were observed among all the FAD cases tested carrying either APP or presenilin 1 (PS1) mutations and most of the sporadic cases of AD (SAD). Different patterns of A beta(5-x) distribution were found in the mouse models carrying different combinations of autosomal mutations in the APP, PS1 and Tau genes. All of them showed extracellular A beta deposits but none CAA. Additionally, they were all affected by a severe amyloid pathology in the hippocampus among other areas. Interestingly, neither 5XFAD nor APP/PS1KI showed any evidence for intraneuronal A beta(5-x). Conclusions: Different degrees of A beta(5-x) accumulations can be found in the transgenic AD mouse models and human cases expressing the sporadic or the familial form of the disease. Due to the lack of intracellular A beta(5-x), these isoforms might not be contributing to early mechanisms in the cascade of events triggering AD pathology. Brain sections obtained from SAD cases showed higher A beta(5-x)-immunoreactivity in vascular deposits than in extracellular plaques, while both are equally important in the FAD cases. The difference may rely on alternative mechanisms involving A beta(5-x) peptides and operating in a divergent way in the late and early onset forms of the disease.
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| 13. |
- Linnankivi, T, et al.
(författare)
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Cerebroretinal microangiopathy with calcifications and cysts.
- 2006
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Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 67:8, s. 1437-43
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Extensive cerebral calcifications and leukoencephalopathy have been reported in two rare disorders Coats plus and leukoencephalopathy with calcifications and cysts. In the latter, a progressive formation of parenchymal brain cysts is a special feature, whereas Coats plus is characterized by intrauterine growth retardation, bilateral retinal telangiectasias and exudations (Coats disease), sparse hair, and dysplastic nails without cyst formation. METHODS: We identified 13 patients, including two pairs of siblings, with extensive cerebral calcifications and leukoencephalopathy. We reviewed clinical, ophthalmologic, radiologic and neuropathologic data of seven deceased patients and studied five patients prospectively. RESULTS: Eleven patients were small for gestational age; the other symptoms emerged from infancy to adolescence. All patients had neurologic symptoms including seizures, spasticity, dystonia, ataxia, and cognitive decline. Progressive intracerebral calcifications involved deep gray nuclei, brainstem, cerebral and cerebellar white matter, and dentate nuclei and were accompanied by diffuse white matter signal changes and, in five patients, cerebral cysts. Eleven patients had retinal telangiectasias or angiomas. Additional features were skeletal and hematologic abnormalities, intestinal bleeding, and poor growth. Neuropathologic examination showed extensive calcinosis and abnormal small vessels with thickened, hyalinized wall and reduced lumen. CONCLUSIONS: Our data suggest that Coats plus syndrome and leukoencephalopathy with calcifications and cysts belong to the same spectrum. The primary abnormality seems to be an obliterative cerebral angiopathy involving small vessels, leading to dystrophic calcifications via slow necrosis and finally to formation of cysts and secondary white matter abnormalities.
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| 14. |
- Nordfors, K., et al.
(författare)
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Peroxiredoxins and antioxidant enzymes in pilocytic astrocytomas
- 2007
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Ingår i: Clinical Neuropathology. - 0722-5091. ; 26:5, s. 210-218
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Peroxiredoxins are antioxidant enzymes (AOEs), which are redox-regulated thiol proteins with potential effects on the growth, invasion and drug resistance of neoplastic cells. In this study, their biology and clinical significance were examined in pilocytic astrocytomas (PAs). Material and methods: The expression of peroxiredoxins (Prx I-VI) was investigated in 105 PAs by the means of immunohistochemistry and compared with the expression of selected other antioxidant enzymes, cell proliferation, angiogenesis, apoptosis, p53, histopathology and patient survival. Results: Peroxiredoxins were strongly expressed in general suggesting that oxidative damage and consequent defense takes place during the progression of pilocytic astrocytomas. In agreement with this hypothesis, several other AOEs correlated with the degenerative features and angiogenesis possibly associated with reactive oxygen species-derived cellular damage. Moreover, the expression of the AOEs was associated with each other indicating a concurrent activation of the enzymes. With the exception of manganese superoxide dismutase (MnSOD), a strong expression of AOEs was generally associated with higher cell proliferation. Prx VI seemed to have a positive association with a longer recurrence-free interval while other AOEs had no association with patient survival. Many AOEs, such as MnSOD, induce chemo- and radioresistance and are highly elevated in aggressive malignancies. PAs lack this confounding factor, and these tumors are treated only by surgery Conclusions: Taken together, the results of this study on pilocytic astrocytomas suggest that the levels of Prxs and other AOEs and their related thiol proteins are generally strongly expressed in these tumors. At least Prx VI can contribute to tumor behavior which can make it a potential prognostic factor.
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| 15. |
- Rauramaa, T., et al.
(författare)
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TAR-DNA binding protein-43 and alterations in the hippocampus
- 2010
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Ingår i: Abstracts of the XVIIth International Congress of Neuropathology (ICN 2010), Salzburg, Austria, 11-15 September 2010. - : Wiley. ; 20, s. 44-45
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Reinert, Jochim, et al.
(författare)
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A beta(38) in the Brains of Patients with Sporadic and Familial Alzheimer's Disease and Transgenic Mouse Models
- 2014
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 39:4, s. 871-881
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Tidskriftsartikel (refereegranskat)abstract
- The pathogenesis of Alzheimer's disease (AD) is believed to be closely dependent on deposits of neurotoxic amyloid-beta peptides (A beta), which become abundantly present throughout the central nervous system in advanced stages of the disease. The different A beta peptides existing are generated by subsequent cleavage of the amyloid-beta protein precursor (A beta PP) and may vary in length and differ at their C-terminus. Despite extensive studies on the most prevalent species A beta(40) and A beta(42), A beta peptides with other C-termini such as A beta(38) have not received much attention. In the present study, we used a highly specific and sensitive antibody against A beta(38) to analyze the distribution of this A beta species in cases of sporadic and familial AD, as well as in the brains of a series of established transgenic AD mouse models. We found A beta(38) to be present as vascular deposits in the brains of the majority of sporadic AD cases, whereas it is largely absent in non-demented control cases. A beta(38)-positive extracellular plaques were virtually limited to familial cases. Interestingly we observed A beta(38)-positive plaques not only among familial cases due to A beta PP mutations, but also in cases of familial AD caused by presenilin (PSEN) mutations. Furthermore we demonstrate that A beta(38) deposits in the form of extracellular plaques are common in several AD transgenic mouse models carrying either only A beta PP, or combinations of A beta PP, PSEN1, and tau transgenes.
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| 17. |
- Reinert, Jochim, et al.
(författare)
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Deposition of C-terminally truncated A beta species A beta 37 and A beta 39 in Alzheimer's disease and transgenic mouse models
- 2016
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- In Alzheimer's disease (AD) a variety of amyloid beta-peptides (A beta) are deposited in the form of extracellular diffuse and neuritic plaques (NP), as well as within the vasculature. The generation of A beta from its precursor, the amyloid precursor protein (APP), is a highly complex procedure that involves subsequent proteolysis of APP by beta-and gamma-secretases. Brain accumulation of A beta due to impaired A beta degradation and/or altered ratios between the different A beta species produced is believed to play a pivotal role in AD pathogenesis. While the presence of A beta 40 and A beta 42 in vascular and parenchymal amyloid have been subject of extensive studies, the deposition of carboxyterminal truncated A beta peptides in AD has not received comparable attention. In the current study, we for the first time demonstrate the immunohistochemical localization of A beta 37 and A beta 39 in human sporadic AD (SAD). Our study further included the analysis of familial AD (FAD) cases carrying the APP mutations KM670/671NL, E693G and I716F, as well as a case of the PSEN1 Delta Exon9 mutation. A beta 37 and A beta 39 were found to be widely distributed within the vasculature in the brains of the majority of studied SAD and FAD cases, the latter also presenting considerable amounts of A beta 37 containing NPs. In addition, both peptides were found to be present in extracellular plaques but only scarce within the vasculature in brains of a variety of transgenic AD mouse models. Taken together, our study indicates the importance of C-terminally truncated A beta in sporadic and familial AD and raises questions about how these species are generated and regulated.
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| 18. |
- Suomalainen, Anu, et al.
(författare)
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FGF-21 as a biomarker for muscle-manifesting mitochondrial respiratory chain deficiencies: a diagnostic study.
- 2011
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Ingår i: Lancet neurology. - 1474-4465. ; 10:9, s. 806-818
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Muscle biopsy is the gold standard for diagnosis of mitochondrial disorders because of the lack of sensitive biomarkers in serum. Fibroblast growth factor 21 (FGF-21) is a growth factor with regulatory roles in lipid metabolism and the starvation response, and concentrations are raised in skeletal muscle and serum in mice with mitochondrial respiratory chain deficiencies. We investigated in a retrospective diagnostic study whether FGF-21 could be a biomarker for human mitochondrial disorders. METHODS: We assessed samples from adults and children with mitochondrial disorders or non-mitochondrial neurological disorders (disease controls) from seven study centres in Europe and the USA, and recruited healthy volunteers (healthy controls), matched for age where possible, from the same centres. We used ELISA to measure FGF-21 concentrations in serum or plasma samples (abnormal values were defined as >200 pg/mL). We compared these concentrations with values for lactate, pyruvate, lactate-to-pyruvate ratio, and creatine kinase in serum or plasma and calculated sensitivity, specificity, and positive and negative predictive values for all biomarkers. FINDINGS: We analysed serum or plasma from 67 patients (41 adults and 26 children) with mitochondrial disorders, 34 disease controls (22 adults and 12 children), and 74 healthy controls. Mean FGF-21 concentrations in serum were 820 (SD 1151) pg/mL in adult and 1983 (1550) pg/mL in child patients with respiratory chain deficiencies and 76 (58) pg/mL in healthy controls. FGF-21 concentrations were high in patients with mitochondrial disorders affecting skeletal muscle but not in disease controls, including those with dystrophies. In patients with abnormal FGF-21 concentrations in serum, the odds ratio of having a muscle-manifesting mitochondrial disease was 132·0 (95% CI 38·7-450·3). For the identification of muscle-manifesting mitochondrial disease, the sensitivity was 92·3% (95% CI 81·5-97·9%) and specificity was 91·7% (84·8-96·1%). The positive and negative predictive values for FGF-21 were 84·2% (95% CI 72·1-92·5%) and 96·1 (90·4-98·9%). The accuracy of FGF-21 to correctly identify muscle-manifesting respiratory chain disorders was better than that for all conventional biomarkers. The area under the receiver-operating-characteristic curve for FGF-21 was 0·95; by comparison, the values for other biomarkers were 0·83 lactate (p=0·037, 0·83 for pyruvate (p=0·015), 0·72 for the lactate-to-pyruvate ratio (p=0·0002), and 0·77 for creatine kinase (p=0·013). INTERPRETATION: Measurement of FGF-21 concentrations in serum identified primary muscle-manifesting respiratory chain deficiencies in adults and children and might be feasible as a first-line diagnostic test for these disorders to reduce the need for muscle biopsy. FUNDING: Sigrid Jusélius Foundation, Jane and Aatos Erkko Foundation, Molecular Medicine Institute of Finland, University of Helsinki, Helsinki University Central Hospital, Academy of Finland, Novo Nordisk, Arvo and Lea Ylppö Foundation.
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