| 1. |
- Laake, Jon Henrik, et al.
(författare)
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A simple in vitro model of ischemia based on hippocampal slice cultures and propidium iodide fluorescence
- 1999
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Ingår i: Brain Research Protocols. - 1385-299X. ; 4:2, s. 173-184
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Tidskriftsartikel (refereegranskat)abstract
- This protocol describes a model of cerebral ischemia based on organotypic hippocampal slice cultures and quantitative assessment of cell death by use of propidium iodide and image analysis. The cultures were made from rat hippocampal slices that were obtained at postnatal day 4-7 and allowed to develop for > 14 days in vitro. For induction of 'in vitro ischemia', the cultures were washed in glucose free buffer and the culture chamber flooded with a nitrogen/carbon dioxide mixture until the oxygen concentration was < 1.0%. The cultures were exposed to this atmosphere for 30-35 min, washed in serum-free medium, and returned to ordinary growth medium. After 24 h, dead cells were quantified by use of propidium iodide. The cell death resulting from the oxygen/glucose deprivation was largely confined to the CA1 region and was blocked by NMDA-receptor antagonists but not by antagonists to AMPA-receptors or metabotropic glutamate receptors. The type of cell death was judged to be necrotic, based on ultrastructural observations. The oxygen/glucose deprived cultures exhibited increased phosphorylation of the MAP kinase cascade. This activation of the MAP kinase cascade was blocked by NMDA-receptor antagonists. The in vitro model described in the present report is simple to use and reproduces many features of in vivo ischemia, including the preferential vulnerability of CA1 cells. The model should be suited to analyses of the mechanisms underlying the regionally selective cell death in the hippocampus and ischemic cell death in general.
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| 2. |
- Larsson, Max, et al.
(författare)
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Quantitative analysis of immunogold labeling indicates low levels and non-vesicular localization of L-aspartate in rat primary afferent terminals.
- 2001
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Ingår i: Journal of Comparative Neurology. - : John Wiley & Sons. - 0021-9967 .- 1096-9861. ; 430:2, s. 147-159
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Tidskriftsartikel (refereegranskat)abstract
- The role of L-aspartate as an excitatory neurotransmitter in primary afferent synapses in the spinal cord dorsal horn is disputed. To further investigate this issue, we examined the presence of aspartate-like immunoreactivity in primary afferent nerve terminals and other tissue components of the dorsal horn. We also examined the relationship between aspartate and glutamate immunogold labeling density and the density of synaptic vesicles in primary afferent terminals and presumed inhibitory terminals forming symmetric synapses. Weak aspartate immunosignals, similar to or lower than those displayed by presumed inhibitory terminals, were detected in both C-fiber primary afferent terminals in lamina II (dense sinusoid axon terminals, identified by morphological criteria) and in A-fiber primary afferent terminals in laminae III-IV (identified with anterograde transport of choleragenoid-horseradish peroxidase conjugate). The aspartate immunogold signal in primary afferent terminals was only about one-fourth of that in deep dorsal horn neuronal cell bodies. Further, whereas significant positive correlations were evident between synaptic vesicle density and glutamate immunogold labeling density in both A- and C-fiber primary afferent terminals, none of the examined terminal populations displayed a significant correlation between synaptic vesicle density and aspartate immunogold labeling density. Thus, our results indicate relatively low levels and a non-vesicular localization of aspartate in primary afferent terminals. It is therefore suggested that aspartate, rather than being a primary afferent neurotransmitter, serves a role in the intermediary metabolism in primary afferent terminals.
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| 3. |
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| 4. |
- Rundén, Elise, et al.
(författare)
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Regional selective neuronal degeneration after protein phosphatase inhibition in hippocampal slice cultures : Evidence for a MAP kinase-dependent mechanism
- 1998
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Ingår i: The Journal of Neuroscience. - 0270-6474. ; 18:18, s. 7296-7305
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Tidskriftsartikel (refereegranskat)abstract
- The regional selectivity and mechanisms underlying the toxicity of the serine/threonine protein phosphatase inhibitor okadaic acid (OA) were investigated in hippocampal slice cultures. Image analysis of propidium iodide-labeled cultures revealed that okadaic acid caused a dose- and time- dependent injury to hippocampal neurons. Pyramidal cells in the CA3 region and granule cells in the dentate gyrus were much more sensitive to okadaic acid than the pyramidal cells in the CA1 region. Electron microscopy revealed ultrastructural changes in the pyramidal cells that were not consistent with an apoptotic process. Treatment with okadaic acid led to a rapid and sustained tyrosine phosphorylation of the mitogen-activated protein kinases ERK1 and ERK2 (p44/42 (mapk)). The phosphorylation was markedly reduced after treatment of the cultures with the microbial alkaloid K-252a (a nonselective protein kinase inhibitor) or the MAP kinase kinase (MEK1/2) inhibitor PD98059. K-252a and PD98059 also ameliorated the okadaic acid-induced cell death. Inhibitors of protein kinase C, Ca2+/calmodulin-dependent protein kinase II, or tyrosine kinase were ineffective. These results indicate that sustained activation of the MAP kinase pathway, as seen after e.g., ischemia, may selectively harm specific subsets of neurons. The susceptibility to MAP kinase activation of the CA3 pyramidal cells and dentate granule cells may provide insight into the observed relationship between cerebral ischemia and dementia in Alzheimer's disease.
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| 5. |
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| 6. |
- Skauli, Nadia, et al.
(författare)
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Canonical Bone Morphogenetic Protein Signaling Regulates Expression of Aquaporin-4 and Its Anchoring Complex in Mouse Astrocytes
- 2022
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Ingår i: Frontiers in Cellular Neuroscience. - : Frontiers Media SA. - 1662-5102. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Aquaporin-4 (AQP4) is the predominant water channel in the brain; it is enriched in astrocytic foot processes abutting vessels where it is anchored through an interaction with the dystrophin-associated protein (DAP) complex. Enhanced expression with concomitant mislocalization of AQP4 along astrocyte plasma membranes is a hallmark of several neurological conditions. Thus, there is an urgent need to identify which signaling pathways dictate AQP4 microdistribution. Here we show that canonical bone morphogenetic proteins (BMPs), particularly BMP2 and 4, upregulate AQP4 expression in astrocytes and dysregulate the associated DAP complex by differentially affecting its individual members. We further demonstrate the presence of BMP receptors and Smad1/5/9 pathway activation in BMP treated astrocytes. Our analysis of adult mouse brain reveals BMP2 and 4 in neurons and in a subclass of endothelial cells and activated Smad1/5/9 in astrocytes. We conclude that the canonical BMP-signaling pathway might be responsible for regulating the expression of AQP4 and of DAP complex proteins that govern the subcellular compartmentation of this aquaporin.
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| 7. |
- Stenzinger, Albrecht, et al.
(författare)
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Implementation of precision medicine in healthcare—A European perspective
- 2023
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Ingår i: Journal of Internal Medicine. - 0954-6820 .- 1365-2796. ; 294:4, s. 437-454
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Forskningsöversikt (refereegranskat)abstract
- The technical development of high-throughput sequencing technologies and the parallel development of targeted therapies in the last decade have enabled a transition from traditional medicine to personalized treatment and care. In this way, by using comprehensive genomic testing, more effective treatments with fewer side effects are provided to each patient—that is, precision or personalized medicine (PM). In several European countries—such as in England, France, Denmark, and Spain—the governments have adopted national strategies and taken “top-down” decisions to invest in national infrastructure for PM. In other countries—such as Sweden, Germany, and Italy with regionally organized healthcare systems—the profession has instead taken “bottom-up” initiatives to build competence networks and infrastructure to enable equal access to PM. In this review, we summarize key learnings at the European level on the implementation process to establish sustainable governance and organization for PM at the regional, national, and EU/international levels. We also discuss critical ethical and legal aspects of implementing PM, and the importance of access to real-world data and performing clinical trials for evidence generation, as well as the need for improved reimbursement models, increased cross-disciplinary education and patient involvement. In summary, PM represents a paradigm shift, and modernization of healthcare and all relevant stakeholders—that is, healthcare, academia, policymakers, industry, and patients—must be involved in this system transformation to create a sustainable, non-siloed ecosystem for precision healthcare that benefits our patients and society at large.
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| 8. |
- Tomson, Göran, et al.
(författare)
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Solidarity and universal preparedness for health after covid-19
- 2021
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Ingår i: The BMJ. - : BMJ Publishing Group Ltd. - 1756-1833. ; 372
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Göran Tomson and colleagues argue that our ability to control pandemics requires global action to counter inequalities from demographic, environmental, technological, and other megatrends
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| 9. |
- Yang, Jing, et al.
(författare)
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Loss of Astrocyte Polarization in the Tg-ArcSwe Mouse Model of Alzheimer's Disease
- 2011
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 27:4, s. 711-722
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Tidskriftsartikel (refereegranskat)abstract
- Aquaporin-4 (AQP4) is the predominant water channel in brain and is selectively expressed in astrocytes. Astrocytic endfoot membranes exhibit tenfold higher densities of AQP4 than non-endfoot membranes, making AQP4 an excellent marker of astrocyte polarization. Loss of astrocyte polarization is known to compromise astrocytic function and to be associated with impaired water and K+ homeostasis. Here we investigate by a combination of light and electron microscopic immunocytochemistry whether amyloid deposition is associated with a loss of astrocyte polarization, using AQP4 as a marker. We used the tg-ArcSwe mouse model of Alzheimer's disease, as this model displays perivascular plaques as well as plaques confined to the neuropil. 3D reconstructions were done to establish the spatial relation between plaques and astrocytic endfeet, the latter known to contain the perivascular pool of AQP4. Changes in AQP4 expression emerge just after the appearance of the first plaques. Typically, there is a loss of AQP4 from endfoot membranes at sites of perivascular amyloid deposits, combined with an upregulation of AQP4 in the neuropil surrounding plaques. By electron microscopy it could be verified that the upregulation reflects an increased concentration of AQP4 in those delicate astrocytic processes that abound in synaptic regions. Thus, astrocytes exhibit a redistribution of AQP4 from endfoot membranes to non-endfoot membrane domains. The present data suggest that the development of amyloid deposits is associated with a loss of astrocyte polarization. The possible perturbation of water and K+ homeostasis could contribute to cognitive decline and seizure propensity in patients with Alzheimer's disease.
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