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1.	Mattsson, Niklas, 1979, et al. (författare) Reduced cerebrospinal fluid BACE1 activity in multiple sclerosis. 2009 Ingår i: Multiple sclerosis (Houndmills, Basingstoke, England). - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 15:4, s. 448-54 Tidskriftsartikel (refereegranskat)abstract BACKGROUND: Cell and animal experiments have shown that beta-site APP-cleaving enzyme 1 (BACE1) may be involved in myelination. OBJECTIVE: Here, we assess the association of cerebrospinal fluid (CSF) BACE1 activity with multiple sclerosis (MS). METHODS: BACE1 activity and levels of secreted amyloid precursor protein (APP) and amyloid-beta (Abeta) isoforms were analyzed in CSF from 100 patients with MS and 114 neurologically healthy controls. Patients with systemic lupus erythematosus (SLE), 26 with and 41 without cerebral engagement, were also included to enable comparisons with regards to another autoimmune disease. A subset of patients with MS and controls underwent a second lumbar puncture after 10 years. RESULTS: MS patients had lower CSF BACE1 activity than controls (P = 0.03) and patients with cerebral SLE (P < 0.001). Patients with cerebral SLE had higher BACE1 activity than any other group (P < 0.05 for all comparisons). BACE1 activity correlated with the different amyloid markers in all study groups. BACE1 activity decreased over 10 years in the MS group (P = 0.039) and correlated weakly with clinical disease severity scores in an inverse manner. CONCLUSIONS: These results suggest an involvement of BACE1 in the MS disease process.
2.	Andreasson, Erik, et al. (författare) The MAP kinase substrate MKS1 is a regulator of plant defence responces 2005 Ingår i: EMBO Journal. - : Wiley. - 1460-2075 .- 0261-4189. ; 24:14, s. 2579-2589 Tidskriftsartikel (refereegranskat)abstract Arabidopsis MAP kinase 4 (MPK4) functions as a regulator of pathogen defense responses, because it is required for both repression of salicylic acid (SA)-dependent resistance and for activation of jasmonate (JA)-dependent defense gene expression. To understand MPK4 signaling mechanisms, we used yeast two-hybrid screening to identify the MPK4 substrate MKS1. Analyses of transgenic plants and genome-wide transcript profiling indicated that MKS1 is required for full SA-dependent resistance in mpk4 mutants, and that overexpression of MKS1 in wild-type plants is sufficient to activate SA-dependent resistance, but does not interfere with induction of a defense gene by JA. Further yeast two-hybrid screening revealed that MKS1 interacts with the WRKY transcription factors WRKY25 and WRKY33. WRKY25 and WRKY33 were shown to be in vitro substrates of MPK4, and a wrky33 knockout mutant was found to exhibit increased expression of the SA-related defense gene PR1. MKS1 may therefore contribute to MPK4-regulated defense activation by coupling the kinase to specific WRKY transcription factors.
3.	Andreasson, Henrik, 1977-, et al. (författare) A Minimalistic Approach to Appearance-Based Visual SLAM 2008 Ingår i: IEEE Transactions on Robotics. - New York, NY, USA : IEEE. - 1552-3098. ; 24:5, s. 991-1001 Tidskriftsartikel (refereegranskat)abstract This paper presents a vision-based approach to SLAM in indoor / outdoor environments with minimalistic sensing and computational requirements. The approach is based on a graph representation of robot poses, using a relaxation algorithm to obtain a globally consistent map. Each link corresponds to a relative measurement of the spatial relation between the two nodes it connects. The links describe the likelihood distribution of the relative pose as a Gaussian distribution. To estimate the covariance matrix for links obtained from an omni-directional vision sensor, a novel method is introduced based on the relative similarity of neighbouring images. This new method does not require determining distances to image features using multiple view geometry, for example. Combined indoor and outdoor experiments demonstrate that the approach can handle qualitatively different environments (without modification of the parameters), that it can cope with violations of the “flat floor assumption” to some degree, and that it scales well with increasing size of the environment, producing topologically correct and geometrically accurate maps at low computational cost. Further experiments demonstrate that the approach is also suitable for combining multiple overlapping maps, e.g. for solving the multi-robot SLAM problem with unknown initial poses.
4.	Andreasson, Henrik (författare) Camera based navigation by mobile robots : local visual feature based localisation and mapping 2009 Bok (övrigt vetenskapligt/konstnärligt)abstract The most important property of a mobile robot is the fact that it is mobile. How to give a robot the skills required to navigate around its environment is therefore an important topic in mobile robotics. Navigation, both for robots and humans, typically involves a map. The map can be used, for example, to estimate a pose based on observations (localisation) or determine a suitable path between to locations. Maps are available nowadays for us humans with few exceptions, however, maps suitable for mobile robots rarely exists. In addition, to relate sensor readings to a map requires that the map content and the observation is compatible, i.e. different robots may require different maps for the same area. This book addresses some of the fundamental problems related to mobile robot navigation (registration, localisation and mapping) using cameras as the primary sensor input. Small salient regions (local visual features) are extracted from each camera image, where each region can be seen as a fingerprint. Many fingerprint matches implicates a high likelihood that they corresponding images originate from a similar location, which is a central property utilised in this work.
5.	Andreasson, Henrik, 1977-, et al. (författare) Has something changed here? : Autonomous difference detection for security patrol robots 2007 Ingår i: 2007 IEEE/RSJ international conference on intelligent robots and systems. - New York, NY, USA : IEEE. - 9781424409129 ; , s. 3429-3435 Konferensbidrag (refereegranskat)abstract This paper presents a system for autonomous change detection with a security patrol robot. In an initial step a reference model of the environment is created and changes are then detected with respect to the reference model as differences in coloured 3D point clouds, which are obtained from a 3D laser range scanner and a CCD camera. The suggested approach introduces several novel aspects, including a registration method that utilizes local visual features to determine point correspondences (thus essentially working without an initial pose estimate) and the 3D-NDT representation with adaptive cell size to efficiently represent both the spatial and colour aspects of the reference model. Apart from a detailed description of the individual parts of the difference detection system, a qualitative experimental evaluation in an indoor lab environment is presented, which demonstrates that the suggested system is able register and detect changes in spatial 3D data and also to detect changes that occur in colour space and are not observable using range values only.
6.	Andreasson, Henrik, et al. (författare) Improving plane extraction from 3D data by fusing laser data and vision 2005 Ingår i: 2005 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2005. (IROS 2005). ; , s. 2656-2661 Konferensbidrag (refereegranskat)abstract The problem of extracting three-dimensional structures from data acquired with mobile robots has received considerable attention over the past years. Robots that are able to perceive their three-dimensional environment are envisioned to more robustly perform tasks like navigation, rescue, and manipulation. In this paper we present an approach that simultaneously uses color and range information to cluster 3d points into planar structures. Our current system also is able to calibrate the camera and the laser based on the remission values provided by the range scanner and the brightness of the pixels in the image. It has been implemented on a mobile robot equipped with a manipulator that carries a range scanner and a camera for acquiring colored range scans. Several experiments carried out on real data and in simulations demonstrate that our approach yields highly accurate results also in comparison with previous approaches
7.	Andreasson, Henrik, 1977- (författare) Local visual feature based localisation and mapping by mobile robots 2008 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract This thesis addresses the problems of registration, localisation and simultaneous localisation and mapping (SLAM), relying particularly on local visual features extracted from camera images. These fundamental problems in mobile robot navigation are tightly coupled. Localisation requires a representation of the environment (a map) and registration methods to estimate the pose of the robot relative to the map given the robot’s sensory readings. To create a map, sensor data must be accumulated into a consistent representation and therefore the pose of the robot needs to be estimated, which is again the problem of localisation. The major contributions of this thesis are new methods proposed to address the registration, localisation and SLAM problems, considering two different sensor configurations. The first part of the thesis concerns a sensor configuration consisting of an omni-directional camera and odometry, while the second part assumes a standard camera together with a 3D laser range scanner. The main difference is that the former configuration allows for a very inexpensive set-up and (considering the possibility to include visual odometry) the realisation of purely visual navigation approaches. By contrast, the second configuration was chosen to study the usefulness of colour or intensity information in connection with 3D point clouds (“coloured point clouds”), both for improved 3D resolution (“super resolution”) and approaches to the fundamental problems of navigation that exploit the complementary strengths of visual and range information. Considering the omni-directional camera/odometry setup, the first part introduces a new registration method based on a measure of image similarity. This registration method is then used to develop a localisation method, which is robust to the changes in dynamic environments, and a visual approach to metric SLAM, which does not require position estimation of local image features and thus provides a very efficient approach. The second part, which considers a standard camera together with a 3D laser range scanner, starts with the proposal and evaluation of non-iterative interpolation methods. These methods use colour information from the camera to obtain range information at the resolution of the camera image, or even with sub-pixel accuracy, from the low resolution range information provided by the range scanner. Based on the ability to determine depth values for local visual features, a new registration method is then introduced, which combines the depth of local image features and variance estimates obtained from the 3D laser range scanner to realise a vision-aided 6D registration method, which does not require an initial pose estimate. This is possible because of the discriminative power of the local image features used to determine point correspondences (data association). The vision-aided registration method is further developed into a 6D SLAM approach where the optimisation constraint is based on distances of paired local visual features. Finally, the methods introduced in the second part are combined with a novel adaptive normal distribution transform (NDT) representation of coloured 3D point clouds into a robotic difference detection system.
8.	Andreasson, Henrik, et al. (författare) Localization for mobile robots using panoramic vision, local features and particle filter 2005 Ingår i: Proceedings of the 2005 IEEE International Converence on Robotics and Automation. ; , s. 3348-3353 Konferensbidrag (refereegranskat)abstract In this paper we present a vision-based approach to self-localization that uses a novel scheme to integrate featurebased matching of panoramic images with Monte Carlo localization. A specially modified version of Lowe’s SIFT algorithm is used to match features extracted from local interest points in the image, rather than using global features calculated from the whole image. Experiments conducted in a large, populated indoor environment (up to 5 persons visible) over a period of several months demonstrate the robustness of the approach, including kidnapping and occlusion of up to 90% of the robot’s field of view.
9.	Andreasson, Henrik, 1977-, et al. (författare) Mini-SLAM : minimalistic visual SLAM in large-scale environments based on a new interpretation of image similarity 2007 Ingår i: 2007 IEEE international conference on robotics and automation (ICRA). - New York, NY, USA : IEEE. - 9781424406012 ; , s. 4096-4101 Konferensbidrag (refereegranskat)abstract This paper presents a vision-based approach to SLAM in large-scale environments with minimal sensing and computational requirements. The approach is based on a graphical representation of robot poses and links between the poses. Links between the robot poses are established based on odometry and image similarity, then a relaxation algorithm is used to generate a globally consistent map. To estimate the covariance matrix for links obtained from the vision sensor, a novel method is introduced based on the relative similarity of neighbouring images, without requiring distances to image features or multiple view geometry. Indoor and outdoor experiments demonstrate that the approach scales well to large-scale environments, producing topologically correct and geometrically accurate maps at minimal computational cost. Mini-SLAM was found to produce consistent maps in an unstructured, large-scale environment (the total path length was 1.4 km) containing indoor and outdoor passages.
10.	Andreasson, Henrik, 1977-, et al. (författare) Non-iterative Vision-based Interpolation of 3D Laser Scans 2007 Ingår i: Autonomos Agents and Robots. - Berlin/Heidelberg, Germany : Springer. - 9783540734239 ; , s. 83-90 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract 3D range sensors, particularly 3D laser range scanners, enjoy a rising popularity and are used nowadays for many different applications. The resolution 3D range sensors provide in the image plane is typically much lower than the resolution of a modern colour camera. In this chapter we focus on methods to derive a highresolution depth image from a low-resolution 3D range sensor and a colour image. The main idea is to use colour similarity as an indication of depth similarity, based on the observation that depth discontinuities in the scene often correspond to colour or brightness changes in the camera image. We present five interpolation methods and compare them with an independently proposed method based on Markov random fields. The proposed algorithms are non-iterative and include a parameter-free vision-based interpolation method. In contrast to previous work, we present ground truth evaluation with real world data and analyse both indoor and outdoor data.
11.	Andreasson, Henrik, et al. (författare) Self-localization in non-stationary environments using omni-directional vision 2007 Ingår i: Robotics and Autonomous Systems. - Amsterdam : Elsevier. - 0921-8890 .- 1872-793X. ; 55:7, s. 541-551 Tidskriftsartikel (refereegranskat)abstract This paper presents an image-based approach for localization in non-static environments using local feature descriptors, and its experimental evaluation in a large, dynamic, populated environment where the time interval between the collected data sets is up to two months. By using local features together with panoramic images, robustness and invariance to large changes in the environment can be handled. Results from global place recognition with no evidence accumulation and a Monte Carlo localization method are shown. To test the approach even further, experiments were conducted with up to 90% virtual occlusion in addition to the dynamic changes in the environment
12.	Andreasson, Henrik, 1977-, et al. (författare) Vision aided 3D laser scanner based registration 2007 Ingår i: ECMR 2007. ; , s. 192-197 Konferensbidrag (refereegranskat)abstract This paper describes a vision and 3D laser based registration approach which utilizes visual features to identify correspondences. Visual features are obtained from the images of a standard color camera and the depth of these features is determined by interpolating between the scanning points of a 3D laser range scanner, taking into consideration the visual information in the neighbourhood of the respective visual feature. The 3D laser scanner is also used to determine a position covariance estimate of the visual feature. To exploit these covariance estimates, an ICP algorithm based on the Mahalanobis distance is applied. Initial experimental results are presented in a real world indoor laboratory environment
13.	Andreasson, Henrik, 1977-, et al. (författare) Vision based interpolation of 3D laser scans 2006 Ingår i: Proceedings of the Third International Conference on Autonomous Robots and Agents. ; , s. 455-460 Konferensbidrag (refereegranskat)abstract 3D range sensors, particularly 3D laser range scanners, enjoy a rising popularity and are used nowadays for many different applications. The resolution 3D range sensors provide in the image plane is typically much lower than the resolution of a modern color camera. In this paper we focus on methods to derive a high-resolution depth image from a low-resolution 3D range sensor and a color image. The main idea is to use color similarity as an indication of depth similarity, based on the observation that depth discontinuities in the scene often correspond to color or brightness changes in the camera image. We present five interpolation methods and compare them with an independently proposed method based on Markov Random Fields. The algorithms proposed in this paper are non-iterative and include a parameter-free vision-based interpolation method. In contrast to previous work, we present ground truth evaluation with real world data and analyse both indoor and outdoor data. Further, we suggest and evaluate four methods to determine a confidence measure for the accuracy of interpolated range values.
14.	Andreasson, Ulf, 1967- (författare) Arbetslösa i rörelse : Organisationssträvanden och politisk kamp inom arbetslöshetsrörelsen i Sverige, 1920-34 2008 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract This doctoral thesis sets out to analyse the development of the unemployed movement in Sweden during the period 1920–34. The study is divided into two parts. The first is empirical and descriptive while the second is interpretive and explanatory, and seeks to examine why this phenomenon developed in the way it did. Mass unemployment in Sweden between the World Wars did not cause the same social tensions as in many other countries. This relative peace endured despite high and consistent unemployment and hard living conditions for the unemployed. These conditions served as sources for tensions present in the unemployed movement, and which some actors sought to take advantage of and even exacerbate. Andréasson argues that a major reason that society did not take a more radical turn in the period was that the reformist labour movement actively moderated these tensions. This was done by the Social Democratic Party (SAP) changing the environment of the unemployed organisations, for example by using local unemployment policy to polish off the rough edges of the national unemployment policy. More important was the crisis politics in the early 1930s that helped narrow the socio-economic gap between those who had and those who did not have a job. The Swedish Trade Union Confederation (LO) neutralised the movement of the unemployed by introducing changes within the unemployed movement itself, involving a variety of strategies. After 1933, the LO and SAP dominated and were able to direct the activities of most of the organisations that existed. Gaining control over the unemployed was as important for the LO and SAP as being able to exert control over other forces that might threaten to weaken their long-term strategies and aims. There was a conviction within the unemployed movement that mass unemployment was largely a consequence of technological developments in production. This argument had roots dating back to the early stages of industrialism in England when Luddites had attacked production machinery. The coalition of organisations of unemployed workers in Sweden during the 1920s and 1930s did not seriously consider engaging in machine-breaking activities. The movement’s criticism of technology did not extend into the Swedish model which envisioned the development of machinery as a way to prevent rising unemployment.
15.	Andreasson, Ulf, 1968, et al. (författare) Aspects of beta-amyloid as a biomarker for Alzheimer's disease 2007 Ingår i: Biomarkers in Medicine. - : Future Medicine Ltd. - 1752-0363 .- 1752-0371. ; 1:1, s. 59-78 Forskningsöversikt (refereegranskat)abstract Alzheimer’s disease is an age-related neurodegenerative disorder that results in progressive cognitive impairment and death. The accumulation of β-amyloid (Aβ) in specific brain regions is believed by many to represent the earliest event in the pathogenesis of the disease. Here, we review the key aspects of Aβ as a biomarker for Alzheimer’s disease, including the pathogenicity of Aβ, the possible biological functions of its precursor protein, the Aβ metabolism and homeostasis, the diagnostic performance of different Aβ assays in different settings and the potential usefulness of Aβ as a surrogate marker for treatment efficacy in clinical trials of novel Aβ-targeting drugs against Alzheimer’s disease.
16.	Bjerke, Maria, 1977, et al. (författare) Subcortical vascular dementia biomarker pattern in mild cognitive impairment. 2009 Ingår i: Dementia and geriatric cognitive disorders. - : S. Karger AG. - 1421-9824 .- 1420-8008. ; 28:4, s. 348-56 Tidskriftsartikel (refereegranskat)abstract BACKGROUND: Mild cognitive impairment (MCI) is an etiologically unclear disorder. Cerebrospinal fluid (CSF) biomarkers are potentially useful for the differentiation between various MCI etiologies. AIM: The aim of the study was to assess whether baseline CSF hyperphosphorylated tau (P-tau), total tau (T-tau), amyloid beta 1-42 (Abeta(42)) and neurofilament light (NF-L) in patients with MCI could predict subcortical vascular dementia (SVD) and Alzheimer's disease (AD) at follow-up. METHODS: Biomarker levels were assessed by Luminex xMAP technology and ELISA. RESULTS: Increased baseline concentrations of NF-L significantly separated MCI-SVD from stable MCI. The MCI-SVD patients were inseparable from stable MCI but separable from patients developing AD (MCI-AD) on the basis of Abeta(42,) T-tau and P-tau(181) levels. CONCLUSION: A combination of the biomarkers Abeta(42), T-tau, P-tau(181) and NF-L has the potential to improve the clinical separation of MCI-SVD patients from stable MCI and MCI-AD patients.
17.	Blennow, Mats, et al. (författare) Omhändertagande av det asfyktiska barnet 2008 Ingår i: Lärobok i neonatologi. Redaktörer: Lagercrantz, H; Hellström-Vestas, L; Norrman, M. - : Studentlitteratur. - 9789144046433 ; , s. 57-76 Bokkapitel (övrigt vetenskapligt/konstnärligt)
18.	Bouguerra, Abdelbaki, 1974-, et al. (författare) An autonomous robotic system for load transportation 2009 Ingår i: 2009 IEEE Conference on Emerging Technologies & Factory Automation (EFTA 2009). - New York : IEEE conference proceedings. - 9781424427277 - 9781424427284 ; , s. 1563-1566 Konferensbidrag (refereegranskat)abstract This paper presents an overview of an autonomous robotic material handling system. The goal of the system is to extend the functionalities of traditional AGVs to operate in highly dynamic environments. Traditionally, the reliable functioning of AGVs relies on the availability of adequate infrastructure to support navigation. In the target environments of our system, such infrastructure is difficult to setup in an efficient way. Additionally, the location of objects to handle are unknown, which requires that the system be able to detect and track object positions at runtime. Another requirement of the system is to be able to generate trajectories dynamically, which is uncommon in industrial AGV systems.
19.	Bouguerra, Abdelbaki, et al. (författare) MALTA : a system of multiple autonomous trucks for load transportation 2009 Ingår i: Proceedings of the 4th European conference on mobile robots (ECMR). - Zagreb : KoREMA. - 9789536037544 ; , s. 93-98 Konferensbidrag (refereegranskat)abstract This paper presents an overview of an autonomousrobotic material handling system. The goal of the system is toextend the functionalities of traditional AGVs to operate in highlydynamic environments. Traditionally, the reliable functioning ofAGVs relies on the availability of adequate infrastructure tosupport navigation. In the target environments of our system,such infrastructure is difficult to setup in an efficient way.Additionally, the location of objects to handle are unknown,which requires that the system be able to detect and track objectpositions at runtime. Another requirement of the system is to beable to generate trajectories dynamically, which is uncommon inindustrial AGV systems.
20.	Brinkmalm-Westman, Ann, 1966, et al. (författare) Proteomics/peptidomics tools to find CSF biomarkers for neurodegenerative diseases. 2009 Ingår i: Frontiers in bioscience : a journal and virtual library. - : IMR Press. - 1093-4715. ; 14, s. 1793-806 Forskningsöversikt (refereegranskat)abstract Neurodegenerative diseases are characterized by premature neuronal loss in specific brain regions. During the past decades our knowledge on molecular mechanisms underlying neurodegeneration has increased immensely and resulted in promising drug candidates that might slow down or even stop the neuronal loss. These advances have put a strong focus on the development of diagnostic tools for early or pre-clinical detection of the disorders. In this review we discuss our experience in the field of neuroproteomics/peptidomics, with special focus on biomarker discovery studies that have been performed on CSF samples from well-defined patient and control populations.
21.	Caspersen, Mikael B., et al. (författare) Phosphorylation sites of Arabidopsis MAP kinase substrate 1 (MKS 1) 2007 Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1570-9639. ; 1774:9, s. 1156-1163 Tidskriftsartikel (refereegranskat)abstract The Arabidopsis MAP kinase 4 (MPK4) substrate MKS1 was expressed in Escherichia coli and purified, full-length, 6x histidine (His)-tagged MKS1 was phosphorylated in vitro by hemagglutinin (HA)-tagged MPK4 immuno-precipitated from plants. MKS1 phosphorylation was initially verified by electrophoresis and gel-staining with ProQ Diamond and the protein was digested by either trypsin or chymotrypsin for maximum sequence coverage to facilitate identification of phosphorylated positions. Prior to analysis by mass spectrometry, samples were either desalted, passed over TiO2 or both for improved phosphopeptide detection. As MAP kinases generally phosphorylate serine or threonine followed by proline (Ser/Thr-Pro), theoretical masses of potentially phosphorylated peptides were calculated and mass spectrometric peaks matching these masses were fragmented and searched for a neutral-loss signal at similar to 98 Da indicative of phosphorylation. Additionally, mass spectrometric peaks present in the MPK4-treated MKS1, but not in the control peptide map of untreated MKS1, were fragmented. Fragmentation spectra were subjected to a MASCOT database search which identified three of the twelve Ser-Pro serine residues (Ser72, Set108, Ser120) in the phosphorylated form.
22.	Fleck, Sven, et al. (författare) Omnidirectional 3D modeling on a mobile robot using graph cuts 2005 Ingår i: Proceedings of the 2005 IEEE International Converence on Robotics and Automation. ; , s. 1748-1754 Konferensbidrag (refereegranskat)abstract For a mobile robot it is a natural task to build a 3D model of its environment. Such a model is not only useful for planning robot actions but also to provide a remote human surveillant a realistic visualization of the robot’s state with respect to the environment. Acquiring 3D models of environments is also an important task on its own with many possible applications like creating virtual interactive walkthroughs or as basis for 3D-TV.In this paper we present our method to acquire a 3D model using a mobile robot that is equipped with a laser scanner and a panoramic camera. The method is based on calculating dense depth maps for panoramic images using pairs of panoramic images taken from different positions using stereo matching. Traditional 2D-SLAM using laser-scan-matching is used to determine the needed camera poses. To receive high-quality results we use a high-quality stereo matching algorithm – the graph cut method. We describe the necessary modifications to handle panoramic images and specialized post-processing methods.
23.	Gisslén, Magnus, 1962, et al. (författare) Amyloid and tau cerebrospinal fluid biomarkers in HIV infection. 2009 Ingår i: BMC neurology. - : Springer Science and Business Media LLC. - 1471-2377. ; 9:1 Tidskriftsartikel (refereegranskat)abstract ABSTRACT: BACKGROUND: Because of the emerging intersections of HIV infection and Alzheimer's disease, we examined cerebrospinal fluid (CSF) biomarkers related of amyloid and tau metabolism in HIV-infected patients. METHODS: In this cross-sectional study we measured soluble amyloid precursor proteins alpha and beta (sAPPalpha and sAPPbeta), amyloid beta fragment 1-42 (Abeta1-42), and total and hyperphosphorylated tau (t-tau and p-tau) in CSF of 86 HIV-infected (HIV+) subjects, including 21 with AIDS dementia complex (ADC), 25 with central nervous system (CNS) opportunistic infections and 40 without neurological symptoms and signs. We also measured these CSF biomarkers in 64 uninfected (HIV-) subjects, including 21 with Alzheimer's disease, and both younger and older controls without neurological disease. RESULTS: CSF sAPPalpha and sAPPbeta concentrations were highly correlated and reduced in patients with ADC and opportunistic infections compared to the other groups. The opportunistic infection group but not the ADC patients had lower CSF Abeta1-42 in comparison to the other HIV+ subjects. CSF t-tau levels were high in some ADC patients, but did not differ significantly from the HIV+ neuroasymptomatic group, while CSF p-tau was not increased in any of the HIV+ groups. Together, CSF amyloid and tau markers segregated the ADC patients from both HIV+ and HIV- neuroasymptomatics and from Alzheimer's disease patients, but not from those with opportunistic infections. CONCLUSIONS: Parallel reductions of CSF sAPPalpha and sAPPbeta in ADC and CNS opportunistic infections suggest an effect of CNS immune activation or inflammation on neuronal amyloid synthesis or processing. Elevation of CSF t-tau in some ADC and CNS infection patients without concomitant increase in p-tau indicates neural injury without preferential accumulation of hyperphosphorylated tau as found in Alzheimer's disease. These biomarker changes define pathogenetic pathways to brain injury in ADC that differ from those of Alzheimer's disease.
24.	Hansson, Oskar, et al. (författare) Prediction of Alzheimer's disease using the CSF A beta 42/A beta 40 ratio in patients with mild cognitive impairment 2007 Ingår i: DEMENTIA AND GERIATRIC COGNITIVE DISORDERS. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 23:5, s. 316-320 Tidskriftsartikel (refereegranskat)abstract Evidence supports an important role for β-amyloid (Aβ) in the pathogenesis of Alzheimer’s disease (AD). Here, we investigate baseline levels of the 40- and 42-amino-acid-long Aβ peptides (Aβ40 and Aβ42) in cerebrospinal fluid (CSF) from a cohort of patients with mild cognitive impairment (MCI, n = 137) in relation to the final diagnosis after 4–6 years of follow-up time. CSF Aβ42 concentration at baseline and the Aβ42/Aβ40 ratio were significantly decreased in the MCI patients who developed AD as compared to cognitively stable MCI patients and MCI patients who developed other forms of dementia (p < 0.001). The baseline levels of Aβ40 were similar in all MCI groups but correlated with change in Mini Mental State Examination scores in converters to AD. The Aβ42/Aβ40 ratio was superior to Aβ42 concentration with regard to identifying incipient AD in MCI (p < 0.05). In conclusion, the data provide further support for the view that amyloid precursor protein metabolism is disturbed in early sporadic AD and points to the usefulness of the Aβ42/Aβ40 ratio as a predictive biomarker for AD.
25.	Hansson, Sarah, 1976, et al. (författare) Cystatin C in cerebrospinal fluid and multiple sclerosis. 2007 Ingår i: Annals of neurology. - : Wiley. - 0364-5134. ; 62:2, s. 193-196 Tidskriftsartikel (refereegranskat)abstract OBJECTIVE: A recent study using surface-enhanced laser desorption/ionization time-of-flight analysis of cerebrospinal fluid identified a 12.5 kDa truncated isoform of cystatin C (CysC) as a specific biomarker for multiple sclerosis (MS). METHODS: Surface-enhanced laser desorption/ionization time-of-flight analysis of cerebrospinal fluid samples from 43 MS patients and 46 healthy control subjects. RESULTS: Full-length CysC (13.4 kDa) concentration was similar in MS and control samples. The 12.5 kDa CysC protein was produced from full-length CysC by N-terminal cleavage during storage at -20 degrees C. INTERPRETATION: The 12.5 kDa CysC isoform is a storage-related artifact and is not useful as a diagnostic marker for MS.
26.	Hansson, Sarah, 1976, et al. (författare) Reduced levels of amyloid-beta-binding proteins in cerebrospinal fluid from Alzheimer's disease patients. 2009 Ingår i: Journal of Alzheimer's disease : JAD. - 1387-2877. ; 16:2, s. 389-97 Tidskriftsartikel (refereegranskat)abstract Amyloid-beta(Abeta) aggregation is a major hallmark of Alzheimer's disease (AD). Previous studies have suggested that only unbound Abeta can take part in the aggregation process. Therefore, endogenous Abeta-binding proteins may have an important role in preventing AD. Here, we analyzed cerebrospinal fluid (CSF) samples from 35 subjects with AD, 18 subjects with frontotemporal dementia (FTD) and 29 non-demented controls to test if reduced Abeta-binding capacity in CSF is a specific feature of AD. A panel of known Abeta-binding CSF proteins, including beta-trace/prostaglandin D2 synthase (beta-trace), transthyretin (TTR), cystatin C (CysC) and alpha(1)-antitrypsin (AAT), were quantified and related to diagnosis and CSF levels of Abeta(1-38), Abeta(1-40) and Abeta(1-42). AD patients displayed a mild reduction in the CSF levels of beta-trace (p=0.020), CysC (p=0.017), AAT (p=0.019) and TTR (p=0.012) compared with controls. While the reductions in AAT and TTR were AD-specific, the levels of beta-trace and CysC were also reduced in FTD. As expected, CSF Abeta(1-42) was reduced in AD compared with controls (p=0.00005) and with FTD patients (p=0.015). Positive correlations between Abeta(1-42) and beta-trace, CysC and TTR, respectively, were seen only in the AD group, suggesting that deficient Abeta-binding capacity in CSF may contribute to the amyloidogenic process in AD.
27.	Magnusson, Martin, 1977-, et al. (författare) Appearance-based loop detection from 3D laser data using the normal distributions transform 2009 Ingår i: IEEE International Conference on Robotics and Automation 2009 (ICRA '09). - : IEEE conference proceedings. - 9781424427888 - 9781424427895 ; , s. 23-28 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract We propose a new approach to appearance based loop detection from metric 3D maps, exploiting the NDT surface representation. Locations are described with feature histograms based on surface orientation and smoothness, and loop closure can be detected by matching feature histograms. We also present a quantitative performance evaluation using two realworld data sets, showing that the proposed method works well in different environments.Â© 2009 IEEE.
28.	Magnusson, Martin, et al. (författare) Automatic appearance-based loop detection from three-dimensional laser data using the normal distributions transform 2009 Ingår i: Journal of Field Robotics. - : Wiley-Blackwell. - 1556-4959 .- 1556-4967. ; 26:11-12, s. 892-914 Tidskriftsartikel (refereegranskat)abstract We propose a new approach to appearance-based loop detection for mobile robots, usingthree-dimensional (3D) laser scans. Loop detection is an important problem in the simultaneouslocalization and mapping (SLAM) domain, and, because it can be seen as theproblem of recognizing previously visited places, it is an example of the data associationproblem. Without a flat-floor assumption, two-dimensional laser-based approaches arebound to fail in many cases. Two of the problems with 3D approaches that we address inthis paper are how to handle the greatly increased amount of data and how to efficientlyobtain invariance to 3D rotations.We present a compact representation of 3D point cloudsthat is still discriminative enough to detect loop closures without false positives (i.e.,detecting loop closure where there is none). A low false-positive rate is very important becausewrong data association could have disastrous consequences in a SLAM algorithm.Our approach uses only the appearance of 3D point clouds to detect loops and requires nopose information. We exploit the normal distributions transform surface representationto create feature histograms based on surface orientation and smoothness. The surfaceshape histograms compress the input data by two to three orders of magnitude. Becauseof the high compression rate, the histograms can be matched efficiently to compare theappearance of two scans. Rotation invariance is achieved by aligning scans with respectto dominant surface orientations. We also propose to use expectation maximization to fit a gamma mixture model to the output similarity measures in order to automatically determinethe threshold that separates scans at loop closures from nonoverlapping ones.Wediscuss the problem of determining ground truth in the context of loop detection and thedifficulties in comparing the results of the few available methods based on range information.Furthermore, we present quantitative performance evaluations using three realworlddata sets, one of which is highly self-similar, showing that the proposed methodachieves high recall rates (percentage of correctly identified loop closures) at low falsepositiverates in environments with different characteristics.
29.	Portelius, Erik, 1977, et al. (författare) An Alzheimer's disease-specific beta-amyloid fragment signature in cerebrospinal fluid. 2006 Ingår i: Neuroscience letters. - : Elsevier BV. - 0304-3940. ; 409:3, s. 215-9 Tidskriftsartikel (refereegranskat)abstract Pathogenic events in Alzheimer's disease (AD) involve an imbalance between the production and clearance of the neurotoxic beta-amyloid peptide (Abeta), especially the 42 amino acid peptide Abeta1-42. While much is known about the production of Abeta1-42, many questions remain about how the peptide is degraded. To investigate the degradation pattern, we developed a method based on immunoprecipitation combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry that determines the Abeta degradation fragment pattern in cerebrospinal fluid (CSF). We found in total 18 C-terminally and 2 N-terminally truncated Abeta peptides and preliminary data indicated that there were differences in the detected Abeta relative abundance pattern between AD and healthy controls. Here, we provide direct evidence that an Abeta fragment signature consisting of Abeta1-16, Abeta1-33, Abeta1-39, and Abeta1-42 in CSF distinguishes sporadic AD patients from non-demented controls with an overall accuracy of 86%.
30.	Portelius, Erik, 1977, et al. (författare) Characterization of amyloid β peptides in cerebrospinal fluid by an automated immunoprecipitation procedure followed by mass spectrometry 2007 Ingår i: Journal of proteome research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 6:11, s. 4433-4439 Tidskriftsartikel (refereegranskat)
31.	Portelius, Erik, 1977, et al. (författare) Targeted proteomics in Alzheimer's disease: focus on amyloid-beta. 2008 Ingår i: Expert review of proteomics. - : Informa UK Limited. - 1744-8387 .- 1478-9450. ; 5:2, s. 225-37 Forskningsöversikt (refereegranskat)abstract Diagnosis and monitoring of sporadic Alzheimer's disease (AD) have long depended on clinical examination of individuals with end-stage disease. However, upcoming anti-AD therapies are optimally initiated when individuals show very mild signs of neurodegeneration. There is a developing consensus for cerebrospinal fluid amyloid-beta (Abeta) as a core biomarker for the mild cognitive impairment stage of AD. Abeta is directly involved in the pathogenesis of AD or tightly correlated with other primary pathogenic factors. It is produced from amyloid precursor protein (APP) by proteolytic processing that depends on the beta-site APP-cleaving enzyme 1 and the gamma-secretase complex, and is degraded by a broad range of proteases. This review summarizes targeted proteomic studies of Abeta in biological fluids and identifies clinically useful markers of disrupted Abeta homeostasis in AD. The next 5 years will see a range of novel assays developed on the basis of these results. From a longer perspective, establishment of the most effective combinations of different biomarkers and other diagnostic modalities may be foreseen.
32.	Tamimi, Hashem, et al. (författare) Localization of mobile robots with omnidirectional vision using Particle Filter and iterative SIFT 2006 Ingår i: Robotics and Autonomous Systems. - : Elsevier BV. - 0921-8890 .- 1872-793X. ; 54:9, s. 758-765 Tidskriftsartikel (refereegranskat)abstract The Scale Invariant Feature Transform, SIFT, has been successfully applied to robot localization. Still, the number of features extracted with this approach is immense, especially when dealing with omnidirectional vision. In this work, we propose a new approach that reduces the number of features generated by SIFT as well as their extraction and matching time. With the help of a Particle Filter, we demonstrate that we can still localize the mobile robot accurately with a lower number of features
33.	Tamimi, Hashem, et al. (författare) Localization of mobile robots with omnidirectional vision using particle filter and iterative SIFT 2005 Konferensbidrag (refereegranskat)abstract The Scale Invariant Feature Transform, SIFT, has been successfully applied to robot localization. Still, the number of features extracted with this approach is immense, especially when dealing with omnidirectional vision. In this work, we propose a new approach that reduces the number of features generated by SIFT as well as their extraction and matching time. With the help of a particle filter, we demonstrate that we can still localize the mobile robot accurately with a lower number of features
34.	Zetterberg, Henrik, 1973, et al. (författare) Clinical proteomics in neurodegenerative disorders. 2008 Ingår i: Acta neurologica Scandinavica. - : Hindawi Limited. - 1600-0404 .- 0001-6314. ; 118:1, s. 1-11 Forskningsöversikt (refereegranskat)abstract Neurodegenerative disorders are characterized by neuronal impairment that eventually leads to neuronal death. In spite of the brain's known capacity for regeneration, lost neurons are difficult to replace. Therefore, drugs aimed at inhibiting neurodegenerative processes are likely to be most effective if the treatment is initiated as early as possible. However, clinical manifestations in early disease stages are often numerous, subtle and difficult to diagnose. This is where biomarkers that specifically reflect onset of pathology, directly or indirectly, may have a profound impact on diagnosis making in the future. A triplet of biomarkers for Alzheimer's disease (AD), total and hyperphosphorylated tau and the 42 amino acid isoform of beta-amyloid, has already been established for early detection of AD before the onset of dementia. However, more biomarkers are needed both for AD and for other neurodegenerative disorders, such as Parkinson's disease, frontotemporal dementia and amyotrophic lateral sclerosis. This review provides an update on recent advances in clinical neuroproteomics, a biomarker discovery field that has expanded immensely during the last decade, and gives an overview of the most commonly used techniques and the major clinically relevant findings these techniques have lead to.
35.	Zetterberg, Henrik, 1973, et al. (författare) CSF antithrombin III and disruption of the blood-brain barrier. 2009 Ingår i: Journal of clinical oncology : official journal of the American Society of Clinical Oncology. - 1527-7755. ; 27:13 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
36.	Zetterberg, Henrik, 1973, et al. (författare) Elevated cerebrospinal fluid BACE1 activity in incipient Alzheimer disease. 2008 Ingår i: Archives of neurology. - : American Medical Association (AMA). - 1538-3687 .- 0003-9942. ; 65:8, s. 1102-7 Tidskriftsartikel (refereegranskat)abstract BACKGROUND: We used a sensitive and specific beta-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) assay to determine the relationship between BACE1 activity in cerebrospinal fluid (CSF) and markers of APP metabolism and axonal degeneration in early and late stages of Alzheimer disease (AD). OBJECTIVE: To assess CSF BACE1 activity in AD. DESIGN: Case-control and longitudinal follow-up study. SETTING: Specialized memory clinic. Patients Eighty-seven subjects with AD, 33 cognitively normal control subjects, and 113 subjects with mild cognitive impairment (MCI), who were followed up for 3 to 6 years. MAIN OUTCOME MEASURES: Cerebrospinal fluid BACE1 activity in relation to diagnosis and CSF levels of secreted APP and amyloid beta protein (Abeta) isoforms and the axonal degeneration marker total tau. RESULTS: Subjects with AD had higher CSF BACE1 activity (median, 30 pM [range, 11-96 pM]) than controls (median, 23 pM [range, 8-43 pM]) (P =.02). Subjects with MCI who progressed to AD during the follow-up period had higher baseline BACE1 activity (median, 35 pM [range, 18-71 pM]) than subjects with MCI who remained stable (median, 29 pM [range, 14-83 pM]) (P < .001) and subjects with MCI who developed other forms of dementia (median, 20 pM [range, 10-56 pM]) (P <.001). BACE1 activity correlated positively with CSF levels of secreted APP isoforms and Abeta(40) in the AD and control groups and in all MCI subgroups (P < .05) except the MCI subgroup that developed AD. Strong positive correlations were found between CSF BACE1 activity and total tau levels in all MCI subgroups (r >or= 0.57, P
37.	Åstrand, Björn, 1969-, et al. (författare) An Autonomous Robotic System for Load Transportation 2009 Ingår i: Proceedings of the 4th Swedish Workshop on Autonomous Robotics (SWAR). - Västerås : Mälardalen University. ; , s. 56-57 Konferensbidrag (refereegranskat)

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