| 1. |
|
|
| 2. |
- Wallén-Mackenzie, Åsa, et al.
(författare)
-
Restricted cortical and amygdaloid removal of vesicular glutamate transporter 2 in preadolescent mice impacts dopaminergic activity and neuronal circuitry of higher brain function.
- 2009
-
Ingår i: The Journal of neuroscience : the official journal of the Society for Neuroscience. - 1529-2401 .- 0270-6474. ; 29:7, s. 2238-51
-
Tidskriftsartikel (refereegranskat)abstract
- A major challenge in neuroscience is to resolve the connection between gene functionality, neuronal circuits, and behavior. Most, if not all, neuronal circuits of the adult brain contain a glutamatergic component, the nature of which has been difficult to assess because of the vast cellular abundance of glutamate. In this study, we wanted to determine the role of a restricted subpopulation of glutamatergic neurons within the forebrain, the Vglut2-expressing neurons, in neuronal circuitry of higher brain function. Vglut2 expression was selectively deleted in the cortex, hippocampus, and amygdala of preadolescent mice, which resulted in increased locomotor activity, altered social dominance and risk assessment, decreased sensorimotor gating, and impaired long-term spatial memory. Presynaptic VGLUT2-positive terminals were lost in the cortex, striatum, nucleus accumbens, and hippocampus, and a downstream effect on dopamine binding site availability in the striatum was evident. A connection between the induced late-onset, chronic reduction of glutamatergic neurotransmission and dopamine signaling within the circuitry was further substantiated by a partial attenuation of the deficits in sensorimotor gating by the dopamine-stabilizing antipsychotic drug aripiprazole and an increased sensitivity to amphetamine. Somewhat surprisingly, given the restricted expression of Vglut2 in regions responsible for higher brain function, our analyses show that VGLUT2-mediated neurotransmission is required for certain aspects of cognitive, emotional, and social behavior. The present study provides support for the existence of a neurocircuitry that connects changes in VGLUT2-mediated neurotransmission to alterations in the dopaminergic system with schizophrenia-like behavioral deficits as a major outcome.
|
|
| 3. |
- Adelöf, Julia, 1990, et al.
(författare)
-
PA28αβ overexpression enhances learning and memory of female mice without inducing 20S proteasome activity
- 2018
-
Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 19:1
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The proteasome system plays an important role in synaptic plasticity. Induction and maintenance of long term potentiation is directly dependent on selective targeting of proteins for proteasomal degradation. The 20S proteasome activator PA28αβ activates hydrolysis of small nonubiquitinated peptides and possesses protective functions upon oxidative stress and proteinopathy. The effect of PA28αβ activity on behavior and memory function is, however, not known. We generated a mouse model that overexpresses PA28α (PA28αOE) to understand PA28αβ function during healthy adult homeostasis via assessment of physiological and behavioral profiles, focusing on female mice. RESULTS: PA28α and PA28β protein levels were markedly increased in all PA28αOE tissues analyzed. PA28αOE displayed reduced depressive-like behavior in the forced swim test and improved memory/learning function assessed by intersession habituation in activity box and shuttle box passive avoidance test, with no significant differences in anxiety or general locomotor activity. Nor were there any differences found when compared to WT for body composition or immuno-profile. The cognitive effects of PA28αOE were female specific, but could not be explained by alterations in estrogen serum levels or hippocampal regulation of estrogen receptor β. Further, there were no differences in hippocampal protein expression of neuronal or synaptic markers between PA28αOE and WT. Biochemical analysis of hippocampal extracts demonstrated that PA28α overexpression did not increase PA28-20S peptidase activity or decrease K48-polyubiquitin levels. Instead, PA28αOE exhibited elevated efficiency in preventing aggregation in the hippocampus. CONCLUSIONS: This study reveals, for the first time, a connection between PA28αβ and neuronal function. We found that PA28α overexpressing female mice displayed reduced depressive-like behavior and enhanced learning and memory. Since the positive effects of PA28α overexpression arose without an activation of 20S proteasome capacity, they are likely independent of PA28αβ's role as a 20S proteasome activator and instead depend on a recognized chaperone-like function. These findings suggest that proteostasis in synaptic plasticity is more diverse than previously reported, and demonstrates a novel function of PA28αβ in the brain.
|
|
| 4. |
- Ahl, Matilda, et al.
(författare)
-
Immune response in blood before and after epileptic and psychogenic non-epileptic seizures
- 2023
-
Ingår i: Heliyon. - : Elsevier. - 2405-8440. ; 9:3
-
Tidskriftsartikel (refereegranskat)abstract
- Inflammatory processes may provoke epileptic seizures and seizures may promote an immune reaction. Hence, the systemic immune reaction is a tempting diagnostic and prognostic marker in epilepsy. We explored the immune response before and after epileptic and psychogenic non-epileptic seizures (PNES). Serum samples collected from patients with videoEEG-verified temporal or frontal lobe epilepsy (TLE or FLE) or TLE + PNES showed increased interleukin-6 (IL-6) levels in between seizures (interictally), compared to controls. Patients with PNES had no increase in IL-6. The IL-6 levels increased transiently even further within hours after a seizure (postictally) in TLE but not in FLE patients. The postictal to interictal ratio of additionally five immune factors were also increased in TLE patients only. We conclude that immune factors have the potential to be future biomarkers for epileptic seizures and that the heterogeneity among different epileptic and non-epileptic seizures may be disclosed in peripheral blood sampling independent of co-morbidities.
|
|
| 5. |
- Alsholm, Linda, et al.
(författare)
-
Interrupted transport by the emergency medical service in stroke/transitory ischemic attack : A consequence of changed treatment routines in prehospital emergency care.
- 2019
-
Ingår i: Brain and Behavior. - : Wiley. - 2162-3279 .- 2162-3279.
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The discovery that not all patients who call for the emergency medical service (EMS) require transport to hospital has changed the structure of prehospital emergency care. Today, the EMS clinician at the scene already distinguishes patients with a time-critical condition such as stroke/transitory ischemic attack (TIA) from patients without. This highlights the importance of the early identification of stroke/TIA.AIM: To describe patients with a final diagnosis of stroke/TIA whose transport to hospital was interrupted either due to a lack of suspicion of the disease by the EMS crew or due to refusal by the patient or a relative/friend.METHODS: Data were obtained from a register in Gothenburg, covering patients hospitalised due to a final diagnosis of stroke/TIA. The inclusion criterion was that patients were assessed by the EMS but were not directly transported to hospital by the EMS.RESULTS: Among all the patients who were assessed by the EMS nurse and subsequently diagnosed with stroke or TIA in 2015, the transport of 34 of 1,310 patients (2.6%) was interrupted. Twenty-five of these patients, of whom 20 had a stroke and five had a TIA, are described in terms of initial symptoms and outcome. The majority had residual symptoms at discharge from hospital. Initial symptoms were vertigo/disturbed balance in 11 of 25 cases. Another three had symptoms perceived as a change in personality and three had a headache.CONCLUSION: From this pilot study, we hypothesise that a fraction of patients with stroke/TIA who call for the EMS have their direct transport to hospital interrupted due to a lack of suspicion of the disease by the EMS nurse at the scene. These patients appear to have more vague symptoms including vertigo and disturbed balance. Instruments to identify these patients at the scene are warranted.
|
|
| 6. |
- Andersson, My, 1980
(författare)
-
Astrocyte-mediated short-term synaptic depression
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Short-term synaptic plasticity, the activity-dependent regulation of synaptic efficacy that occurs in the timeframe of milliseconds to seconds, is a fundamental property of the synapse, mostly attributed to changes in release probability. These changes are commonly ascribed to intrinsic mechanisms in the presynaptic terminal and to different transmitters acting on the presynaptic terminal. Astrocytes are the most abundant cell type in the brain. It has become increasingly clear that they can have a more active role in regulating neuronal signalling than their first established role of providing neuronal support. Astrocytes send out processes, which enwrap the synapses, in an ideal position to respond to synaptic transmission and in turn modulate synaptic function, such as short-term plasticity. However, not much is known about how astrocytes affect short-term synaptic plasticity. The overall objective of this thesis was to examine the possible involvement of astrocyte-synapse signalling in short-term synaptic plasticity in the hippocampus. We used the acute rat hippocampal slice preparation and recorded the transmission at the glutamatergic CA3-CA1 synapses using extracellular and whole-cell patch-clamp recordings. Hippocampal CA3-CA1 synapses as a population exhibit facilitation or augmentation milliseconds and seconds after a brief synaptic burst. However, we found that in the intermediate timeframe, between a couple of hundred milliseconds to seconds, these synapses exhibit a postburst depression (PBD). This PBD was found to be expressed as a reduction of release probability. The PBD displayed a cooperativity threshold as it was necessary to activate a critical number of synapses in order to elicit the depression. We found that the PBD develops over the first three postnatal weeks and that it is blocked when astrocyte metabolism is compromised. The PBD was blocked when a calcium chelator was delivered into the astrocytic network through a patch pipette, showing a requirement for astrocytic signalling. Activation leading to PBD homosynaptically, also gave rise to a decrease in release probability in neighbouring inactive synapses, a transient heterosynaptic depression (tHeSD). The tHeSD developed over the same period as the PBD and was blocked by a blocker of astrocyte metabolism. In addition, the tHeSD was blocked by application of gap junction blockers. The tHeSD relied on GABAB and mGlu II/III receptors, but not on NMDA, adenosine A1 or mGlu I receptors. Analysis of paired-pulse plasticity and relative vesicle pool size suggest that the tHeSD is expressed as a depression of resting vesicular release probability, causing a large increase of the paired-pulse ratio. In addition, the PBD was suggested to be a combination of vesicle depletion and augmentation, causing no change and a large decrease in paired-pulse ratio, respectively. Hippocampal pyramidal neurons typically fire action potentials in short bursts in the behaving animal, at frequencies suitable for eliciting the PBD and the tHeSD. This suggests that astrocytes are critically involved in mediating a negative feedback synaptic transmission after a burst of synaptic activity.
|
|
| 7. |
- Andersson, My, 1980, et al.
(författare)
-
Astrocyte-mediated short-term synaptic depression in the rat hippocampal CA1 area: two modes of decreasing release probability.
- 2011
-
Ingår i: BMC neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: Synaptic burst activation feeds back as a short-term depression of release probability at hippocampal CA3-CA1 synapses. This short-term synaptic plasticity requires functional astrocytes and it affects both the recently active (< 1 s) synapses (post-burst depression) as well as inactive neighboring synapses (transient heterosynaptic depression). The aim of this study was to investigate and compare the components contributing to the depression of release probability in these two different scenarios. RESULTS: When tested using paired-pulses, following a period of inactivity, the transient heterosynaptic depression was expressed as a reduction in the response to only the first pulse, whereas the response to the second pulse was unaffected. This selective depression of only the first response in a high-frequency burst was shared by the homosynaptic post-burst depression, but it was partially counteracted by augmentation at these recently active synapses. In addition, the expression of the homosynaptic post-burst depression included an astrocyte-mediated reduction of the pool of release-ready primed vesicles. CONCLUSIONS: Our results suggest that activated astrocytes depress the release probability via two different mechanisms; by depression of vesicular release probability only at inactive synapses and by imposing a delay in the recovery of the primed pool of vesicles following depletion. These mechanisms restrict the expression of the astrocyte-mediated depression to temporal windows that are typical for synaptic burst activity.
|
|
| 8. |
- Andersson, My, 1980, et al.
(författare)
-
Astrocytes impose postburst depression of release probability at hippocampal glutamate synapses.
- 2010
-
Ingår i: The Journal of neuroscience : the official journal of the Society for Neuroscience. - 1529-2401. ; 30:16, s. 5776-80
-
Tidskriftsartikel (refereegranskat)abstract
- Many neurons typically fire action potentials in brief, high-frequency bursts with specific consequences for their synaptic output. Here we have examined short-term plasticity engaged during burst activation using electrophysiological recordings in acute rat hippocampal slices. We show that CA3-CA1 glutamate synapses exhibit a prominent depression of presynaptic release probability for approximately 1 s after such a burst. This postburst depression exhibits a distinct cooperativity threshold, is abolished by inhibiting astrocyte metabolism and astrocyte calcium signaling, and is not operational in the developing hippocampus. Our results suggest that astrocytes are actively involved in short-term synaptic depression, shaping synaptic activity during behaviorally relevant neural activity.
|
|
| 9. |
- Andersson, My, 1980, et al.
(författare)
-
Astrocytes play a critical role in transient heterosynaptic depression in the rat hippocampal CA1 region.
- 2007
-
Ingår i: The Journal of physiology. - : Wiley. - 0022-3751. ; 585:Pt 3, s. 843-52
-
Tidskriftsartikel (refereegranskat)abstract
- Active synapses can reduce the probability of transmitter release at neighbouring synapses. Depending on whether such heterosynaptic depression is mediated by intersynaptic diffusion of transmitter or by release of gliotransmitters, astrocytes should either hinder or promote the heterosynaptic depression. In the present study we have examined the developmental profile and astrocytic involvement in a transient heterosynaptic depression (tHeSD) in the CA1 region of the rat hippocampal slice preparation. A short stimulus burst (3 impulses at 50 Hz) to one group of synapses elicited a depression of the field EPSP evoked in another group of synapses that amounted to about 25% 0.5 s after the conditioning burst. This tHeSD was associated with an increase in the paired-pulse ratio of about 30%. The tHeSD was not present in slices from rats younger than 10 postnatal days and developed towards the adult magnitude between postnatal days 10 and 20. The tHeSD was totally prevented by the glia-specific toxin fluoroacetate (FAC), by carbenoxolone, a general blocker of connexin-based channels, and by endothelin, an endogenous peptide that has been shown to block astrocytic connexin-based channels. Antagonists to GABA(B) receptors and group II/III metabotropic glutamate receptors (mGluRs) abolished the tHeSD whereas antagonists to NMDA- and adenosine A1 receptors, and to group I mGluRs, did not affect the tHeSD. These results suggest that the tHeSD relies on GABA(B) receptors, group II/III mGluRs and on gliotransmitter release from functionally mature astrocytes.
|
|
| 10. |
- Andersson, My, et al.
(författare)
-
Improved interaction with collaborative robots - evaluation of event-specific haptic feedback in virtual reality
- 2024
-
Ingår i: Procedia Computer Science. - : Elsevier. - 1877-0509. ; 232, s. 1055-1064
-
Tidskriftsartikel (refereegranskat)abstract
- Industry 5.0 adopts a human-centric approach that views humans as a natural part of introducing new technology, such as collaborative robots. However, one of the main challenges in implementing collaborative robots is safety, including the sense of safety. Trust is also a primary challenge when establishing functional collaboration. Influencing factors includes experience and expertise, and research shows that Virtual Reality has the potential to perform such training. This research aims to investigate whether using virtual reality with appropriate feedback can be an effective platform for familiarization and training. In our experiment, we utilized haptic feedback from commercial Virtual Reality controllers to simulate physical interactions with collaborative robots. The experiment involved the participation of fifteen individuals. The results showed that participants regarded haptic feedback while moving as the most appropriate representation. This research aims to identify whether Virtual Reality with suitable feedback can serve as a familiarization and training platform.
|
|
| 11. |
- Andersson, My, et al.
(författare)
-
Optogenetic control of human neurons in organotypic brain cultures
- 2016
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Optogenetics is one of the most powerful tools in neuroscience, allowing for selective control of specific neuronal populations in the brain of experimental animals, including mammals. We report, for the first time, the application of optogenetic tools to human brain tissue providing a proof-of-concept for the use of optogenetics in neuromodulation of human cortical and hippocampal neurons as a possible tool to explore network mechanisms and develop future therapeutic strategies.
|
|
| 12. |
- Andersson, Thomas K., et al.
(författare)
-
Perceptions of Experiences of Recovery After Pancreaticoduodenectomy-A Phenomenographic Interview Study
- 2022
-
Ingår i: Cancer Nursing. - : Ovid Technologies (Wolters Kluwer Health). - 0162-220X .- 1538-9804. ; 45:3, s. 172-180
-
Tidskriftsartikel (refereegranskat)abstract
- Background Pancreatic surgery in the context of enhanced recovery has mainly been evaluated using clinical variables. However, there is limited knowledge about patients' perceptions of recovery in this context. Hence, the aim of this study was to explore patients' perceptions of recovery after pancreatic surgery within an enhanced recovery program. Objective To explore the variations in patients' perceptions, a qualitatively designed study was undertaken. Methods Data in this phenomenographic study consisted of interviews with 19 patients at 4 to 6 weeks after surgery. Results Recovery after pancreatic surgery was classified into 5 categories, based on patients' perceptions: to be as before, affected by symptoms, physical activity, understanding the process, and facilitated by other people. Conclusion The study focused on various areas of recovery, which took place between the in-hospital and after-discharge phases. Physical experiences were found to disturb recovery, in contrast to social and emotional experiences, which facilitated recovery. Variations in perceptions of recovery suggest that care may need to be more individualized, both in the preoperative and the postoperative phase. Working with realistic expectations and early patient education might better prepare patients to continue working on their own recovery after discharge from the hospital. Implications for Practice Major cancer surgery needs to be perceived as a personal journey for the patient, even in enhanced recovery program care. Preoperative education is good, but adding continuous and individually adopted education during recovery is better. Knowledge about both hindering and facilitating factors for recovery is important for the healthcare personal.
|
|
| 13. |
- Avaliani, Natalia, et al.
(författare)
-
Directly Converted Human Fibroblasts Mature to Neurons and Show Long-Term Survival in Adult Rodent Hippocampus
- 2017
-
Ingår i: Stem Cells International. - : Hindawi Limited. - 1687-966X .- 1687-9678. ; 2017
-
Tidskriftsartikel (refereegranskat)abstract
- Direct conversion of human somatic cells to induced neurons (iNs), using lineage-specific transcription factors has opened new opportunities for cell therapy in a number of neurological diseases, including epilepsy. In most severe cases of epilepsy, seizures often originate in the hippocampus, where populations of inhibitory interneurons degenerate. Thus, iNs could be of potential use to replace these lost interneurons. It is not known, however, if iNs survive and maintain functional neuronal properties for prolonged time periods in in vivo. We transplanted human fibroblast-derived iNs into the adult rat hippocampus and observed a progressive morphological differentiation, with more developed dendritic arborisation at six months as compared to one month. This was accompanied by mature electrophysiological properties and fast high amplitude action potentials at six months after transplantation. This proof-of-principle study suggests that human iNs can be developed as a candidate source for cell replacement therapy in temporal lobe epilepsy.
|
|
| 14. |
- Avaliani, Natalia, et al.
(författare)
-
Optogenetics reveal delayed afferent synaptogenesis on grafted human induced pluripotent stem cell-derived neural progenitors.
- 2014
-
Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 32:12, s. 3088-3098
-
Tidskriftsartikel (refereegranskat)abstract
- Reprogramming of somatic cells into pluripotency stem cell state have opened new opportunities in cell replacement therapy and disease modeling in a number of neurological disorders. It still remains unknown, however, to what degree the grafted human induced pluripotent stem cells (hiPSCs) differentiate into a functional neuronal phenotype and if they integrate into the host circuitry. Here we present a detailed characterization of the functional properties and synaptic integration of hiPSC-derived neurons grafted in an in vitro model of hyperexcitable epileptic tissue, namely organotypic hippocampal slice cultures (OHSC), and in adult rats in vivo. The hiPSCs were first differentiated into long-term self-renewing neuroepithelial stem (lt-NES) cells, which are known to form primarily GABAergic neurons. When differentiated in OHSCs for six weeks, lt-NES cell-derived neurons displayed neuronal properties such as TTX-sensitive sodium currents and action potentials (APs), as well as both spontaneous and evoked postsynaptic currents, indicating functional afferent synaptic inputs. The grafted cells had a distinct electrophysiological profile compared to host cells in the OHSCs with higher input resistance, lower resting membrane potential and APs with lower amplitude and longer duration. To investigate the origin of synaptic afferents to the grafted lt-NES cell-derived neurons, the host neurons were transduced with Channelrhodopsin-2 (ChR2) and optogenetically activated by blue light. Simultaneous recordings of synaptic currents in grafted lt-NES cell-derived neurons using whole-cell patch-clamp technique at 6 weeks after grafting revealed limited synaptic connections from host neurons. Longer differentiation times, up to 24 weeks after grafting in vivo, revealed more mature intrinsic properties and extensive synaptic afferents from host neurons to the It-NES cell-derived neurons, suggesting that these cells require extended time for differentiation/maturation and synaptogenesis. However, even at this later time-point, the grafted cells maintained a higher input resistance. These data indicate that grafted lt-NES cell-derived neurons receive ample afferent input from the host brain. Since the lt-NES cells used in this study show a strong propensity for GABAergic differentiation, the host-to-graft synaptic afferents may facilitate inhibitory neurotransmitter release, and normalize hyperexcitable neuronal networks in brain diseases, e.g. such as epilepsy. Stem Cells 2014.
|
|
| 15. |
- Avdic, Una, et al.
(författare)
-
Levetiracetam and N-Cadherin Antibody Alleviate Brain Pathology Without Reducing Early Epilepsy Development After Focal Non-convulsive Status Epilepticus in Rats
- 2021
-
Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- Focal non-convulsive status epilepticus (fNCSE) is a neurological condition characterized by a prolonged seizure that may lead to the development of epilepsy. Emerging experimental evidence implicates neuronal death, microglial activation and alterations in the excitatory and inhibitory synaptic balance as key features in the pathophysiology following fNCSE. We have previously reported alterations in the excitatory adhesion molecule N-cadherin in rats with fNCSE originating from the hippocampus that subsequently also develop spontaneous seizures. In this study, fNCSE rats were treated intraperitoneally with the conventional anti-epileptic drug levetiracetam in combination with intraparenchymal infusion of N-cadherin antibodies (Ab) for 4 weeks post-fNCSE. The N-cadherin Ab was infused into the fornix and immunohistochemically N-cadherin Ab-stained neurons were detected within the dorsal hippocampal structures as well as in superjacent somatosensory cortex. Continuous levetiracetam treatment for 4 weeks post-fNCSE reduced microglia activation, including cell numbers and morphological changes, partly decreased neuronal cell loss, and excitatory post-synaptic scaffold protein PSD-95 expression in selective hippocampal structures. The additional treatment with N-cadherin Ab did not reverse neuronal loss, but moderately reduced microglial activation, and further reduced PSD-95 levels in the dentate hilus of the hippocampus. Despite the effects on brain pathology within the epileptic focus, neither monotherapy with systemic levetiracetam nor levetiracetam in combination with local N-cadherin Ab administration, reduced the amount of focal or focal evolving into bilateral convulsive seizures, seizure duration, or interictal epileptiform activity during 1 month of continuous electroenephalogram recordings within the hippocampus after fNCSE. Behavioral tests for spatial memory, anxiety, social interaction and anhedonia did not detect gross behavioral differences between fNCSE rats with or without treatment. The results reveal the refractory features of the present rodent model of temporal lobe epilepsy following fNCSE, which supports its clinical value for further therapeutic studies. We identify the persistent development of epilepsy following fNCSE, in spite of partly reduced brain pathology within the epileptic focus.
|
|
| 16. |
- Berglind, Fredrik, et al.
(författare)
-
Dynamic interaction of local and transhemispheric networks is necessary for progressive intensification of hippocampal seizures
- 2018
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- The detailed mechanisms of progressive intensification of seizures often occurring in epilepsy are not well understood. Animal models of kindling, with progressive intensification of stimulation-induced seizures, have been previously used to investigate alterations in neuronal networks, but has been obscured by limited recording capabilities during electrical stimulations. Remote networks in kindling have been studied by physical deletions of the connected structures or pathways, inevitably leading to structural reorganisations and related adverse effects. We used optogenetics to circumvent the above-mentioned problems inherent to electrical kindling, and chemogenetics to temporarily inhibit rather than ablate the remote interconnected networks. Progressively intensifying afterdischarges (ADs) were induced by repetitive photoactivation of principal neurons in the hippocampus of anaesthetized transgenic mice expressing ChR2. This allowed, during the stimulation, to reveal dynamic increases in local field potentials (LFPs), which coincided with the start of AD intensification. Furthermore, chemogenetic functional inhibition of contralateral hippocampal neurons via hM4D(Gi) receptors abrogated AD progression. These findings demonstrate that, during repeated activation, local circuits undergo acute plastic changes with appearance of additional network discharges (LFPs), leading to transhemispheric recruitment of contralateral dentate gyrus, which seems to be necessary for progressive intensification of ADs.
|
|
| 17. |
- Berglind, Fredrik, et al.
(författare)
-
Optogenetic inhibition of chemically induced hypersynchronized bursting in mice.
- 2014
-
Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961. ; 65, s. 133-141
-
Tidskriftsartikel (refereegranskat)abstract
- Synchronized activity is common during various physiological operations but can culminate in seizures and consequently in epilepsy in pathological hyperexcitable conditions in the brain. Many types of seizures are not possible to control and impose significant disability for patients with epilepsy. Such intractable epilepsy cases are often associated with degeneration of inhibitory interneurons in the cortical areas resulting in impaired inhibitory drive onto the principal neurons. Recently emerging optogenetic technique has been proposed as an alternative approach to control such seizures but whether it may be effective in situations where inhibitory processes in the brain are compromised has not been addressed. Here we used pharmacological and optogenetic techniques to block inhibitory neurotransmission and induce epileptiform activity in vitro and in vivo. We demonstrate that NpHR-based optogenetic hyperpolarization and thereby inactivation of a principal neuronal population in the hippocampus is effectively attenuating seizure activity caused by disconnected network inhibition both in vitro and in vivo. Our data suggest that epileptiform activity in the hippocampus caused by impaired inhibition may be controlled by optogenetic silencing of principal neurons and potentially can be developed as an alternative treatment for epilepsy.
|
|
| 18. |
|
|
| 19. |
- Blohm, My, et al.
(författare)
-
Relationship between surgical volume and outcomes in elective and acute cholecystectomy : nationwide, observational study
- 2023
-
Ingår i: British Journal of Surgery. - : Oxford University Press. - 0007-1323 .- 1365-2168. ; 110:3, s. 353-361
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: High surgical volumes are attributed to improved quality of care, especially for extensive procedures. However, it remains unknown whether high-volume surgeons and hospitals have better results in gallstone surgery. The aim of this study was to investigate whether operative volume affects outcomes in cholecystectomies.METHODS: A registry-based cohort study was performed, based on the Swedish Registry of Gallstone Surgery. Cholecystectomies from 2006 to 2019 were included. Annual volumes for the surgeon and hospital were retrieved. All procedures were categorized into volume-based quartiles, with the highest group as reference. Low volume was defined as fewer than 20 operations per surgeon per year and fewer than 211 cholecystectomies per hospital per year. Differences in outcomes were analysed separately for elective and acute procedures.RESULTS: The analysis included 154 934 cholecystectomies. Of these, 101 221 (65.3 per cent) were elective and 53 713 (34.7 per cent) were acute procedures. Surgeons with low volumes had longer operating times (P < 0.001) and higher conversion rates in elective (OR 1.35; P = 0.023) and acute (OR 2.41; P < 0.001) operations. Low-volume surgeons also caused more bile duct injuries (OR 1.41; P = 0.033) and surgical complications (OR 1.15; P = 0.033) in elective surgery, but the results were not statistically significant for acute procedures. Low-volume hospitals had more bile duct injuries in both elective (OR 1.75; P = 0.002) and acute (OR 1.96; P = 0.003) operations, and a higher mortality rate after acute surgery (OR 2.53; P = 0.007).CONCLUSION: This study has demonstrated that operative volumes influence outcomes in cholecystectomy. The results indicate that gallstone surgery should be performed by procedure-dedicated surgeons at hospitals with high volumes of this type of benign surgery.
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
- Dillner, Joakim, et al.
(författare)
-
Antibodies to SARS-CoV-2 and risk of past or future sick leave
- 2021
-
Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- The extent that antibodies to SARS-CoV-2 may protect against future virus-associated disease is unknown. We invited all employees (n=15,300) at work at the Karolinska University Hospital, Stockholm, Sweden to participate in a study examining SARS-Cov-2 antibodies in relation to registered sick leave. For consenting 12,928 healthy hospital employees antibodies to SARS-CoV-2 could be determined and compared to participant sick leave records. Subjects with viral serum antibodies were not at excess risk for future sick leave (adjusted odds ratio (OR) controlling for age and sex: 0.85 [95% confidence interval (CI) (0.85 (0.43-1.68)]. By contrast, subjects with antibodies had an excess risk for sick leave in the weeks prior to testing [adjusted OR in multivariate analysis: 3.34 (2.98-3.74)]. Thus, presence of viral antibodies marks past disease and protection against excess risk of future disease. Knowledge of whether exposed subjects have had disease in the past or are at risk for future disease is essential for planning of control measures.Trial registration: First registered on 02/06/20, ClinicalTrials.gov NCT04411576.
|
|
| 23. |
- Fagevik Olsén, Monika, 1964, et al.
(författare)
-
Development of and adherence to an ERAS® and prehabilitation protocol for patients undergoing pancreatic surgery: An observational study
- 2023
-
Ingår i: Scandinavian Journal of Surgery. - 1457-4969 .- 1799-7267. ; 112:4, s. 235-245
-
Tidskriftsartikel (refereegranskat)abstract
- Background and objective: There are still gaps in knowledge concerning the adherence to different multimodal pathways in pancreatic surgery. The aim of this trial was to explore and evaluate an Enhanced Recovery After Surgery (ERAS®) and prehabilitation protocol in patients undergoing open pancreatic surgery. Methods: Three groups of patients were included: two prospective series of 75 patients undergoing open pancreatic surgery following an ERAS® protocol with or without prehabilitation, and one group of 55 historical controls. Variables regarding adherence to, and effects of the protocols, were collected from the local database and the patients’ hospital records. Patients’ adherence to advice given pre-operatively was followed up using a study-specific questionnaire. Results: The patients reported high adherence to remembered advice given. The health care professionals’ adherence to the various parts of the concepts varied. ERAS® implementation resulted in more frequent gut motility stimulation (p < 0.001) and shorter duration of epidural anesthesia, site drains, and urinary catheter (p = 0.001). With prehabilitation, more patients were screened concerning nutritional status and prescribed preoperative training (p < 001). There was a significant change in weight before surgery, a shorter time to first flatus and a shorter length of stay after implementation of the concepts (p < 0.05). Complications were rare in all three groups and there were no significant differences between the groups. Conclusion: The implementation of an ERAS® and a prehabilitation protocol increased adherence to the protocols by both patients and healthcare professionals. An implementation of an ERAS® protocol with and without prehabilitation decreases length of stay and may decrease preoperative weight loss and time to bowel movement.
|
|
| 24. |
- Forsberg, My, et al.
(författare)
-
Ionized calcium in human cerebrospinal fluid and its influence on intrinsic and synaptic excitability of hippocampal pyramidal neurons in the rat.
- 2019
-
Ingår i: Journal of neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 149:4, s. 452-470
-
Tidskriftsartikel (refereegranskat)abstract
- It is well-known that the extracellular concentration of calcium affects neuronal excitability and synaptic transmission. Less is known about the physiological concentration of extracellular calcium in the brain. In electrophysiological brain slice experiments, the artificial cerebrospinal fluid traditionally contains relatively high concentrations of calcium (2-4 mM) to support synaptic transmission and suppress neuronal excitability. Using an ion-selective electrode, we determined the fraction of ionized calcium in healthy human cerebrospinal fluid to 1.0mM of a total concentration of 1.2 mM (86%). Using patch-clamp and extracellular recordings in the CA1 region in acute slices of rat hippocampus, we then compared the effects of this physiological concentration of calcium with the commonly used 2 mM on neuronal excitability, synaptic transmission, and long-term potentiation (LTP) to examine the magnitude of changes in this range of extracellular calcium. Increasing the total extracellular calcium concentration from 1.2 to 2 mM decreased spontaneous action potential firing, induced a depolarization of the threshold, and increased the rate of both de- and repolarization of the action potential. Evoked synaptic transmission was approximately doubled, with a balanced effect between inhibition and excitation. In 1.2mM calcium high-frequency stimulation did not result in any LTP, whereas a prominent LTP was observed at 2 or 4 mM calcium. Surprisingly, this inability to induce LTP persisted during blockade of GABAergic inhibition. In conclusion, an increase from the physiological 1.2 mM to 2 mM calcium in the artificial cerebrospinal fluid has striking effects on neuronal excitability, synaptic transmission, and the induction of LTP.
|
|
| 25. |
- Gonzalez-Ramos, Ana, et al.
(författare)
-
Human stem cell-derived GABAergic neurons functionally integrate into human neuronal networks
- 2021
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- Gamma-aminobutyric acid (GABA)-releasing interneurons modulate neuronal network activity in the brain by inhibiting other neurons. The alteration or absence of these cells disrupts the balance between excitatory and inhibitory processes, leading to neurological disorders such as epilepsy. In this regard, cell-based therapy may be an alternative therapeutic approach. We generated light-sensitive human embryonic stem cell (hESC)-derived GABAergic interneurons (hdIN) and tested their functionality. After 35 days in vitro (DIV), hdINs showed electrophysiological properties and spontaneous synaptic currents comparable to mature neurons. In co-culture with human cortical neurons and after transplantation (AT) into human brain tissue resected from patients with drug-resistant epilepsy, light-activated channelrhodopsin-2 (ChR2) expressing hdINs induced postsynaptic currents in human neurons, strongly suggesting functional efferent synapse formation. These results provide a proof-of-concept that hESC-derived neurons can integrate and modulate the activity of a human host neuronal network. Therefore, this study supports the possibility of precise temporal control of network excitability by transplantation of light-sensitive interneurons.
|
|
| 26. |
- Gonzalez-Ramos, Ana, et al.
(författare)
-
Transplantation of Human Stem Cell-Derived GABAergic Neurons into the Early Postnatal Mouse Hippocampus to Mitigate Neurodevelopmental Disorders
- 2022
-
Ingår i: Journal of visualized experiments : JoVE. - : MyJove Corporation. - 1940-087X. ; :189
-
Tidskriftsartikel (refereegranskat)abstract
- A reduced number or dysfunction of inhibitory interneurons is a common contributor to neurodevelopmental disorders. Therefore, cell therapy using interneurons to replace or mitigate the effects of altered neuronal circuits is an attractive therapeutic avenue. To this end, more knowledge is needed about how human stem cell-derived GABAergic interneuron-like cells (hdINs) mature, integrate, and function over time in the host circuitry. Of particular importance in neurodevelopmental disorders is a better understanding of whether these processes in transplanted cells are affected by an evolving and maturing host brain. The present protocol describes a fast and highly efficient generation of hdINs from human embryonic stem cells based on the transgenic expression of the transcription factors Ascl1 and Dlx2. These neuronal precursors are transplanted unilaterally, after 7 days in vitro, to the hippocampus of neonatal 2-day-old mice. The transplanted neurons disperse in the ipsi- and contralateral hippocampus of a mouse model of cortical dysplasia-focal epilepsy syndrome and survive for up to 9 months after transplantation. This approach allows for investigating the cellular identity, integration, functionality, and therapeutic potential of transplanted interneurons over an extended time in developing healthy and diseased brains.
|
|
| 27. |
- Havervall, Sebastian, et al.
(författare)
-
Robust humoral and cellular immune responses and low risk for reinfection at least 8 months following asymptomatic to mild COVID-19
- 2022
-
Ingår i: Journal of Internal Medicine. - : John Wiley & Sons. - 0954-6820 .- 1365-2796. ; 291:1, s. 72-80
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Emerging data support detectable immune responses for months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination, but it is not yet established to what degree and for how long protection against reinfection lasts.Methods: We investigated SARS-CoV-2-specific humoral and cellular immune responses more than 8 months post-asymptomatic, mild and severe infection in a cohort of 1884 healthcare workers (HCW) and 51 hospitalized COVID-19 patients. Possible protection against SARS-CoV-2 reinfection was analyzed by a weekly 3-month polymerase chain reaction (PCR) screening of 252 HCW that had seroconverted 7 months prior to start of screening and 48 HCW that had remained seronegative at multiple time points.Results: All COVID-19 patients and 96% (355/370) of HCW who were anti-spike IgG positive at inclusion remained anti-spike IgG positive at the 8-month follow-up. Circulating SARS-CoV-2-specific memory T cell responses were detected in 88% (45/51) of COVID-19 patients and in 63% (233/370) of seropositive HCW. The cumulative incidence of PCR-confirmed SARS-CoV-2 infection was 1% (3/252) among anti-spike IgG positive HCW (0.13 cases per 100 weeks at risk) compared to 23% (11/48) among anti-spike IgG negative HCW (2.78 cases per 100 weeks at risk), resulting in a protective effect of 95.2% (95% CI 81.9%-99.1%).Conclusions: The vast majority of anti-spike IgG positive individuals remain anti-spike IgG positive for at least 8 months regardless of initial COVID-19 disease severity. The presence of anti-spike IgG antibodies is associated with a substantially reduced risk of reinfection up to 9 months following asymptomatic to mild COVID-19.
|
|
| 28. |
- Havervall, Sebastian, et al.
(författare)
-
SARS-CoV-2 induces a durable and antigen specific humoral immunity after asymptomatic to mild COVID-19 infection
- 2022
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17:1, s. e0262169-e0262169
-
Tidskriftsartikel (refereegranskat)abstract
- Current SARS-CoV-2 serological assays generate discrepant results, and the longitudinal characteristics of antibodies targeting various antigens after asymptomatic to mild COVID-19 are yet to be established. This longitudinal cohort study including 1965 healthcare workers, of which 381 participants exhibited antibodies against the SARS-CoV-2 spike antigen at study inclusion, reveal that these antibodies remain detectable in most participants, 96%, at least four months post infection, despite having had no or mild symptoms. Virus neutralization capacity was confirmed by microneutralization assay in 91% of study participants at least four months post infection. Contrary to antibodies targeting the spike protein, antibodies against the nucleocapsid protein were only detected in 80% of previously anti-nucleocapsid IgG positive healthcare workers. Both anti-spike and anti-nucleocapsid IgG levels were significantly higher in previously hospitalized COVID-19 patients four months post infection than in healthcare workers four months post infection (p = 2*10−23 and 2*10−13 respectively). Although the magnitude of humoral response was associated with disease severity, our findings support a durable and functional humoral response after SARS-CoV-2 infection even after no or mild symptoms. We further demonstrate differences in antibody kinetics depending on the antigen, arguing against the use of the nucleocapsid protein as target antigen in population-based SARS-CoV-2 serological surveys
|
|
| 29. |
- Hellström, Ann, 1959, et al.
(författare)
-
Effect of Enteral Lipid Supplement on Severe Retinopathy of Prematurity A Randomized Clinical Trial
- 2021
-
Ingår i: JAMA Pediatrics. - : American Medical Association (AMA). - 2168-6203 .- 2168-6211. ; 175:4, s. 359-367
-
Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE Lack of arachidonic acid (AA) and docosahexaenoic acid (DHA) after extremely preterm birth may contribute to preterm morbidity, including retinopathy of prematurity (ROP). OBJECTIVE To determine whether enteral supplementation with fatty acids from birth to 40 weeks' postmenstrual age reduces ROP in extremely preterm infants. DESIGN, SETTING, AND PARTICIPANTS The Mega Donna Mega trial, a randomized clinical trial, was a multicenter study performed at 3 university hospitals in Sweden from December 15, 2016, to December 15, 2019. The screening pediatric ophthalmologists were masked to patient groupings. A total of 209 infants born at less than 27 weeks' gestation were tested for eligibility, and 206 infants were included. Efficacy analyses were performed on as-randomized groups on the intention-to-treat population and on the per-protocol population using as-treated groups. Statistical analyses were performed from February to April 2020. INTERVENTIONS Infants received either supplementation with an enteral oil providing AA (100mg/kg/d) and DHA (50mg/kg/d) (AA:DHA group) or no supplementation within 3 days after birth until 40 weeks' postmenstrual age. MAIN OUTCOMES AND MEASURES The primary outcomewas severe ROP (stage 3 and/or type 1). The secondary outcomes were AA and DHA serum levels and rates of other complications of preterm birth. RESULTS A total of 101 infants (58 boys [57.4%]; mean [SD] gestational age, 25.5 [1.5] weeks) were included in the AA:DHA group, and 105 infants (59 boys [56.2%]; mean [SD] gestational age, 25.5 [1.4] weeks) were included in the control group. Treatment with AA and DHA reduced severe ROP compared with the standard of care (16 of 101 [15.8%] in the AA:DHA group vs 35 of 105 [33.3%] in the control group; adjusted relative risk, 0.50 [95% CI, 0.28-0.91]; P =.02). The AA:DHA group had significantly higher fractions of AA and DHA in serum phospholipids compared with controls (overall mean difference in AA:DHA group, 0.82 mol% [95% CI, 0.46-1.18 mol%]; P <.001; overall mean difference in control group, 0.13 mol% [95% CI, 0.01-0.24 mol%]; P =.03). There were no significant differences between the AA:DHA group and the control group in the rates of bronchopulmonary dysplasia (48 of 101 [47.5%] vs 48 of 105 [45.7%]) and of any grade of intraventricular hemorrhage (43 of 101 [42.6%] vs 42 of 105 [40.0%]). In the AA:DHA group and control group, respectively, sepsis occurred in 42 of 101 infants (41.6%) and 53 of 105 infants (50.5%), serious adverse events occurred in 26 of 101 infants (25.7%) and 26 of 105 infants (24.8%), and 16 of 101 infants (15.8%) and 13 of 106 infants (12.3%) died. CONCLUSIONS AND RELEVANCE This study found that, compared with standard of care, enteral AA:DHA supplementation lowered the risk of severe ROP by 50% and showed overall higher serum levels of both AA and DHA. Enteral lipid supplementation with AA:DHA is a novel preventive strategy to decrease severe ROP in extremely preterm infants.
|
|
| 30. |
|
|
| 31. |
- Hjorth, Olof, et al.
(författare)
-
Serotonin and dopamine transporter availability in social anxiety disorder after combined treatment with escitalopram and cognitive-behavioral therapy
- 2022
-
Ingår i: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Selective serotonin reuptake inhibitors (SSRIs) and internet-based cognitive behavioral therapy (ICBT) are recommended treatments of social anxiety disorder (SAD), and often combined, but their effects on monoaminergic signaling are not well understood. In this multi-tracer positron emission tomography (PET) study, 24 patients with SAD were randomized to treatment with escitalopram+ICBT or placebo+ICBT under double-blind conditions. Before and after 9 weeks of treatment, patients were examined with positron emission tomography and the radioligands [11C]DASB and [11C]PE2I, probing the serotonin (SERT) and dopamine (DAT) transporter proteins respectively. Both treatment combinations resulted in significant improvement as measured by the Liebowitz Social Anxiety Scale (LSAS). At baseline, SERT-DAT co-expression was high and, in the putamen and thalamus, co-expression showed positive associations with symptom severity. SERT-DAT co-expression was also predictive of treatment success, but predictor-outcome associations differed in direction between the treatments. After treatment, average SERT occupancy in the SSRI + ICBT group was >80%, with positive associations between symptom improvement and occupancy in the nucleus accumbens, putamen and anterior cingulate cortex. Following placebo+ICBT, SERT binding increased in the raphe nuclei. DAT binding increased in both groups in limbic and striatal areas, but relations with symptom improvement differed, being negative for SSRI + ICBT and positive for placebo + ICBT. Thus, serotonin-dopamine transporter co-expression exerts influence on symptom severity and remission rate in the treatment of social anxiety disorder. However, the monoamine transporters are modulated in dissimilar ways when cognitive-behavioral treatment is given concomitantly with either SSRI-medication or pill placebo.
|
|
| 32. |
- Hober, Sophia, Professor, 1965-, et al.
(författare)
-
Systematic evaluation of SARS-CoV-2 antigens enables a highly specific and sensitive multiplex serological COVID-19 assay
- 2021
-
Ingår i: Clinical & Translational Immunology. - : Wiley. - 2050-0068. ; 10:7
-
Tidskriftsartikel (refereegranskat)abstract
- Objective. The COVID-19 pandemic poses an immense need for accurate, sensitive and high-throughput clinical tests, and serological assays are needed for both overarching epidemiological studies and evaluating vaccines. Here, we present the development and validation of a high-throughput multiplex bead-based serological assay. Methods. More than 100 representations of SARS-CoV-2 proteins were included for initial evaluation, including antigens produced in bacterial and mammalian hosts as well as synthetic peptides. The five best-performing antigens, three representing the spike glycoprotein and two representing the nucleocapsid protein, were further evaluated for detection of IgG antibodies in samples from 331 COVID-19 patients and convalescents, and in 2090 negative controls sampled before 2020. Results. Three antigens were finally selected, represented by a soluble trimeric form and the S1-domain of the spike glycoprotein as well as by the C-terminal domain of the nucleocapsid. The sensitivity for these three antigens individually was found to be 99.7%, 99.1% and 99.7%, and the specificity was found to be 98.1%, 98.7% and 95.7%. The best assay performance was although achieved when utilising two antigens in combination, enabling a sensitivity of up to 99.7% combined with a specificity of 100%. Requiring any two of the three antigens resulted in a sensitivity of 99.7% and a specificity of 99.4%. Conclusion. These observations demonstrate that a serological test based on a combination of several SARS-CoV-2 antigens enables a highly specific and sensitive multiplex serological COVID-19 assay.
|
|
| 33. |
- Håkansson, Claes, et al.
(författare)
-
Inter-modality assessment of medial temporal lobe atrophy in a non-demented population: application of a visual rating scale template across radiologists with varying clinical experience
- 2022
-
Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 32, s. 1127-1134
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives To assess inter-modality agreement and accuracy for medial temporal lobe atrophy (MTA) ratings across radiologists with varying clinical experience in a non-demented population. Methods Four raters (two junior radiologists and two senior neuroradiologists) rated MTA on CT and MRI scans using Scheltens' MTA scale. Ratings were compared to a consensus rating by two experienced neuroradiologists for estimation of true positive and negative rates (TPR and TNR) and over- and underestimation of MTA. Inter-modality agreement expressed as Cohen's kappa (dichotomized data), Cohen's kappa(w), and two-way mixed, single measures, consistency ICC (ordinal data) were determined. Adequate agreement was defined as kappa/kappa(w) >= 0.80 and ICC >= 0.80 (significance level at 95% CI >= 0.65). Results Forty-nine subjects (median age 72 years, 27% abnormal MTA) with cognitive impairment were included. Only junior radiologists achieved adequate agreement expressed as Cohen's kappa. All raters achieved adequate agreement expressed as Cohen's kappa(w) and ICC. True positive rates varied from 69 to 100% and TNR varied from 85 to 100%. No under- or overestimation of MTA was observed. Ratings did not differ between radiologists. Conclusion We conclude that radiologists with varying experience achieve adequate inter-modality agreement and similar accuracy when Scheltens' MTA scale is used to rate MTA on a non-demented population. However, TPR varied between radiologists which could be attributed to rating style differences.
|
|
| 34. |
|
|
| 35. |
- Kokaia, Merab, et al.
(författare)
-
An optogenetic approach in epilepsy.
- 2013
-
Ingår i: Neuropharmacology. - : Elsevier BV. - 1873-7064 .- 0028-3908. ; 69:Jun 12, s. 89-95
-
Forskningsöversikt (refereegranskat)abstract
- Optogenetic tools comprise a variety of different light-sensitive proteins from single-cell organisms that can be expressed in mammalian neurons and effectively control their excitability. Two main classes of optogenetic tools allow to either depolarize or hyperpolarize, and respectively generate or inhibit action potentials in selective populations of neurons. This opens unprecedented possibilities for delineating the role of certain neuronal populations in brain processing and diseases. Moreover, optogenetics may be considered for developing potential treatment strategies for brain diseases, particularly for excitability disorders such as epilepsy. Expression of the inhibitory halorhodopsin NpHR in hippocampal principal cells has been recently used as a tool to effectively control chemically and electrically induced epileptiform activity in slice preparations, and to reduce in vivo spiking induced by tetanus toxin injection in the motor cortex. In this review we give a comprehensive summary of what has been achieved so far in the field of epilepsy using optogenetics, and discuss some of the possible strategies that could be envisaged in the future. We also point out some of the challenges and pitfalls in relation to possible outcomes of using optogenetics for controlling network excitability, and associated brain diseases. This article is part of a Special Issue entitled 'Epilepsy'.
|
|
| 36. |
- Ledri, Marco, et al.
(författare)
-
Differential Effect of Neuropeptides on Excitatory Synaptic Transmission in Human Epileptic Hippocampus.
- 2015
-
Ingår i: The Journal of Neuroscience. - 1529-2401. ; 35:26, s. 9622-9631
-
Tidskriftsartikel (refereegranskat)abstract
- Development of novel disease-modifying treatment strategies for neurological disorders, which at present have no cure, represents a major challenge for today's neurology. Translation of findings from animal models to humans represents an unresolved gap in most of the preclinical studies. Gene therapy is an evolving innovative approach that may prove useful for clinical applications. In animal models of temporal lobe epilepsy (TLE), gene therapy treatments based on viral vectors encoding NPY or galanin have been shown to effectively suppress seizures. However, how this translates to human TLE remains unknown. A unique possibility to validate these animal studies is provided by a surgical therapeutic approach, whereby resected epileptic tissue from temporal lobes of pharmacoresistant patients are available for neurophysiological studies in vitro. To test whether NPY and galanin have antiepileptic actions in human epileptic tissue as well, we applied these neuropeptides directly to human hippocampal slices in vitro. NPY strongly decreased stimulation-induced EPSPs in dentate gyrus and CA1 (up to 30 and 55%, respectively) via Y2 receptors, while galanin had no significant effect. Receptor autoradiographic binding revealed the presence of both NPY and galanin receptors, while functional receptor binding was only detected for NPY, suggesting that galanin receptor signaling may be impaired. These results underline the importance of validating findings from animal studies in human brain tissue, and advocate for NPY as a more appropriate candidate than galanin for future gene therapy trials in pharmacoresistant TLE patients.
|
|
| 37. |
- Ledri, Marco, et al.
(författare)
-
Optogenetics for controlling seizure circuits for translational approaches
- 2023
-
Ingår i: Neurobiology of Disease. - 0969-9961. ; 184, s. 1-13
-
Tidskriftsartikel (refereegranskat)abstract
- The advent of optogenetic tools has had a profound impact on modern neuroscience research, revolutionizing our understanding of the brain. These tools offer a remarkable ability to precisely manipulate specific groups of neurons with an unprecedented level of temporal precision, on the order of milliseconds. This breakthrough has significantly advanced our knowledge of various physiological and pathophysiological processes in the brain. Within the realm of epilepsy research, optogenetic tools have played a crucial role in investigating the contributions of different neuronal populations to the generation of seizures and hyperexcitability. By selectively activating or inhibiting specific neurons using optogenetics, researchers have been able to elucidate the underlying mechanisms and identify key players involved in epileptic activity. Moreover, optogenetic techniques have also been explored as innovative therapeutic strategies for treating epilepsy. These strategies aim to halt seizure progression and alleviate symptoms by utilizing the precise control offered by optogenetics. The application of optogenetic tools has provided valuable insights into the intricate workings of the brain during epileptic episodes. For instance, researchers have discovered how distinct interneuron populations contribute to the initiation of seizures (ictogenesis). They have also revealed how remote circuits in regions such as the cerebellum, septum, or raphe nuclei can interact with hyperexcitable networks in the hippocampus. Additionally, studies have demonstrated the potential of closed-loop systems, where optogenetics is combined with real-time monitoring, to enable precise, on-demand control of seizure activity. Despite the immense promise demonstrated by optogenetic approaches, it is important to acknowledge that many of these techniques are still in the early stages of development and have yet to reach potential clinical applications. The transition from experimental research to practical clinical use poses numerous challenges. In this review, we aim to introduce optogenetic tools, provide a comprehensive survey of their application in epilepsy research, and critically discuss their current potential and limitations in achieving successful clinical implementation for the treatment of human epilepsy. By addressing these crucial aspects, we hope to foster a deeper understanding of the current state and future prospects of optogenetics in epilepsy treatment.
|
|
| 38. |
- Martin, Myriam, et al.
(författare)
-
Methods for anti-factor VIII antibody levels in haemophilia A patients-validation of a multiplec immunoassay and comparability with assays measuring non-neutralising and neutralising antibodies (inhibitors)
- 2023
-
Ingår i: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 29:1, s. 336-347
-
Tidskriftsartikel (refereegranskat)abstract
- IntroductionThe development of neutralising (inhibitors) and non-neutralising antibodies (NNAs) is a complication to factor replacement therapy in haemophilia. The diagnostic methods available lack standardisation, have high inter-laboratory variation, and false-negative as well as false-positive results may affect treatment. Both functional inhibitors and NNAs may be detected with higher reproducibility, sensitivity and specificity using the immunological Luminex xMAP-based fluorescence-immunoassay (xFLI).AimValidation of our xFLI and comparability with enzyme-linked immunosorbent assay (ELISA) and chromogenic Nijmegen-Bethesda assay (CBA) for anti-FVIII antibodies in haemophilia A (HA) patients.MethodsThe xFLI method was developed with full-length and B-domain deleted factor coupled to magnetic beads, optimised and validated for performance characteristics. Comparability with ELISA and CBA was evaluated in HA patient samples (n = 112), serial samples in six inhibitor patients and reference interval and decision-limits in healthy donors (n = 44).ResultsThe intra- and inter-assay precision (CV%) for the xFLI method was below 6% and detection limit (LLOQ) .084 ng/mL (NovoEight). All ELISA-positive samples were positive with either Advate or NovoEight. Additionally, 10.7%–14.3% were xFLI-positive and ELISA-negative. All but one CBA-positive sample was above 3SD with xFLI; one was between 2 and 3SD. 29.1% were xFLI-positive and CBA negative. The overall concordance between xFLI and ELISA was 82.1% and xFLI and CBA 77.9%.ConclusionThe anti-FVIII antibody xFLI method is adaptable to clinical practice and more sensitive and reproducible than ELISA and CBA. Actual NNA titers are determined to both full-length and B-domain deleted FVIII. The xFLI is thus valuable for confirmation of all anti-FVIII antibodies.
|
|
| 39. |
- Melin, Esbjörn, et al.
(författare)
-
Disease Modification by Combinatorial Single Vector Gene Therapy : A Preclinical Translational Study in Epilepsy
- 2019
-
Ingår i: Molecular Therapy - Methods and Clinical Development. - : Elsevier BV. - 2329-0501. ; 15, s. 179-193
-
Tidskriftsartikel (refereegranskat)abstract
- Gene therapy has been suggested as a plausible novel approach to achieve seizure control in patients with focal epilepsy that do not adequately respond to pharmacological treatment. We investigated the seizure-suppressant potential of combinatorial neuropeptide Y and Y2 receptor single vector gene therapy based on adeno-associated virus serotype 1 (AAV1) in rats. First, a dose-response study in the systemic kainate-induced acute seizure model was performed, whereby the 1012 genomic particles (gp)/mL titer of the vector was selected as an optimal concentration. Second, an efficacy study was performed in the intrahippocampal kainate chronic model of spontaneous recurrent seizures (SRSs), designed to reflect a likely clinical scenario, with magnetic resonance image (MRI)-guided focal unilateral administration of the vector in the hippocampus during the chronic stage of the disease. The efficacy study demonstrated a favorable outcome of the gene therapy, with a 31% responder rate (more than 50% reduction in SRS frequency) and 13% seizure-freedom rate, whereas no such effects were observed in the control animals. The inter-SRS and SRS cluster intervals were also significantly prolonged in the treated group compared to controls. In addition, the SRS duration was significantly reduced in the treated group but not in the controls. This study establishes the SRS-suppressant ability of the single vector combinatorial neuropeptide Y/Y2 receptor gene therapy in a clinically relevant chronic model of epilepsy.
|
|
| 40. |
- Raymond, Christopher, et al.
(författare)
-
Inclusive conservation and the Post-2020 Global Biodiversity Framework : Tensions and prospects
- 2022
-
Ingår i: One Earth. - : Elsevier BV. - 2590-3330 .- 2590-3322. ; 5:3, s. 252-264
-
Tidskriftsartikel (refereegranskat)abstract
- The draft Post-2020 Global Biodiversity Framework commits to achievement of equity and justice outcomes and represents a “relational turn” in how we understand inclusive conservation. Although “inclusivity” is drawn on as a means to engage diverse stakeholders, widening the framing of inclusivity can create new tensions with regard to how to manage protected areas. We first offer a set of tensions that emerge in the light of the relational turn in biodiversity conservation. Drawing on global case examples applying multiple methods of inclusive conservation, we then demonstrate that, by actively engaging in the interdependent phases of recognizing hybridity, enabling conditions for reflexivity and partnership building, tensions can not only be acknowledged but softened and, in some cases, reframed when managing for biodiversity, equity, and justice goals. The results can improve stakeholder engagement in protected area management, ultimately supporting better implementation of global biodiversity targets.
|
|
| 41. |
|
|
| 42. |
- Renberg, Björn, et al.
(författare)
-
Mimicking silk spinning in a microchip
- 2014
-
Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 195, s. 404-408
-
Tidskriftsartikel (refereegranskat)abstract
- Nature's high performance material, spider silk, is formed during the passage of a protein solution through a spinning duct. Herein we present a microfluidic device with dual laminar mobile phases where silk formation can be mimicked and investigated. Recombinant miniature spidroins, with or without the pH-switching N-terminal domain, were used to investigate spinning conditions into silk-like fibers using this setup.
|
|
| 43. |
- Rudberg, Ann-Sofie, et al.
(författare)
-
SARS-CoV-2 exposure, symptoms and seroprevalence in healthcare workers in Sweden.
- 2020
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- SARS-CoV-2 may pose an occupational health risk to healthcare workers. Here, we report the seroprevalence of SARS-CoV-2 antibodies, self-reported symptoms and occupational exposure to SARS-CoV-2 among healthcare workers at a large acute care hospital in Sweden. The seroprevalence of IgG antibodies against SARS-CoV-2 was 19.1% among the 2149 healthcare workers recruited between April 14th and May 8th 2020, which was higher than the reported regional seroprevalence during the same time period. Symptoms associated with seroprevalence were anosmia (odds ratio (OR) 28.4, 95% CI 20.6-39.5) and ageusia (OR 19.2, 95% CI 14.3-26.1). Seroprevalence was also associated with patient contact (OR 2.9, 95% CI 1.9-4.5) and covid-19 patient contact (OR 3.3, 95% CI 2.2-5.3). These findings imply an occupational risk for SARS-CoV-2 infection among healthcare workers. Continued measures are warranted to assure healthcare workers safety and reduce transmission from healthcare workers to patients and to the community.
|
|
| 44. |
- Sanna, Adriana, et al.
(författare)
-
DNA promoter hypermethylation of melanocyte lineage genes determines melanoma phenotype
- 2022
-
Ingår i: JCI Insight. - : American Society for Clinical Investigation. - 2379-3708. ; 7:19
-
Tidskriftsartikel (refereegranskat)abstract
- Cellular stress contributes to the capacity of melanoma cells to undergo phenotype switching into highly migratory and drug tolerant dedifferentiated states. Such dedifferentiated melanoma cell states are marked by loss of melanocyte specific gene expression and increase of mesenchymal markers. Two crucial transcription factors, MITF and SOX10, important in melanoma development and progression have been implicated in this process. In this study we describe that loss of MITF is associated with a distinct transcriptional program, MITF promoter hypermethylation and poor patient survival in metastatic melanoma. From a comprehensive collection of melanoma cell lines, we observed that MITF methylated cultures were subdivided in two distinct subtypes. Examining mRNA levels of neural crest associated genes we found that one subtype had lost the expression of several lineage genes including SOX10. Intriguingly, SOX10 loss was associated with SOX10 gene promoter hypermethylation and distinct phenotypic and metastatic properties. Depletion of SOX10 in MITF methylated melanoma cells using CRISPR/Cas9 confirmed these findings. In conclusion, this study describes the significance of melanoma state and the underlying functional properties explaining the aggressiveness of such states.
|
|
| 45. |
- Sanna, Adriana, et al.
(författare)
-
DNA promoter hypermethylation of melanocyte lineage genes determines melanoma phenotype.
- 2022
-
Ingår i: JCI insight. - : The American Society for Clinical Investigation. - 2379-3708. ; 7:19
-
Tidskriftsartikel (refereegranskat)abstract
- Cellular stress contributes to the capacity of melanoma cells to undergo phenotype switching into highly migratory and drug-tolerant dedifferentiated states. Such dedifferentiated melanoma cell states are marked by loss of melanocyte-specific gene expression and increase of mesenchymal markers. Two crucial transcription factors, microphthalmia-associated transcription factor (MITF) and SRY-box transcription factor 10 (SOX10), important in melanoma development and progression, have been implicated in this process. In this study we describe that loss of MITF is associated with a distinct transcriptional program, MITF promoter hypermethylation, and poor patient survival in metastatic melanoma. From a comprehensive collection of melanoma cell lines, we observed that MITF-methylated cultures were subdivided in 2 distinct subtypes. Examining mRNA levels of neural crest-associated genes, we found that 1 subtype had lost the expression of several lineage genes, including SOX10. Intriguingly, SOX10 loss was associated with SOX10 gene promoter hypermethylation and distinct phenotypic and metastatic properties. Depletion of SOX10 in MITF-methylated melanoma cells using CRISPR/Cas9 supported these findings. In conclusion, this study describes the significance of melanoma state and the underlying functional properties explaining the aggressiveness of such states.
|
|
| 46. |
- Segerup, My, et al.
(författare)
-
Imitation of Dialects: from South to West
- 1999
-
Ingår i: Fonetik 99 : the Swedish Phonetics Conference June 2-4 1999 : proceedings (Gothenburg papers in theoretical linguistics ; 81). - 0349-1021. ; , s. 121-124
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 47. |
- Sjöbom, Ulrika, et al.
(författare)
-
Modification of serum fatty acids in preterm infants by parenteral lipids and enteral docosahexaenoic acid/arachidonic acid: A secondary analysis of the Mega Donna Mega trial
- 2023
-
Ingår i: Clinical Nutrition. - 0261-5614. ; 42:6, s. 962-971
-
Tidskriftsartikel (refereegranskat)abstract
- Background & aim: Preterm infants risk deficits of long-chain polyunsaturated fatty acids (LCPUFAs) that may contribute to morbidities and hamper neurodevelopment. We aimed to determine longitudinal serum fatty acid profiles in preterm infants and how the profiles are affected by enteral and parenteral lipid sources. Methods: Cohort study analyzing fatty acid data from the Mega Donna Mega study, a randomized control trial with infants born <28 weeks of gestation (n = 204) receiving standard nutrition or daily enteral lipid supplementation with arachidonic acid (AA):docosahexaenoic acid (DHA) (100:50 mg/kg/day). Infants received an intravenous lipid emulsion containing olive oil:soybean oil (4:1). Infants were followed from birth to postmenstrual age 40 weeks. Levels of 31 different fatty acids from serum phospholipids were determined by GC-MS and reported in relative (mol%) and absolute concentration (mmol l-1) units. Results: Higher parenteral lipid administration resulted in lower serum proportion of AA and DHA relative to other fatty acids during the first 13 weeks of life (p < 0.001 for the 25th vs the 75th percentile). The enteral AA:DHA supplement increased the target fatty acids with little impact on other fatty acids. The absolute concentration of total phospholipid fatty acids changed rapidly in the first weeks of life, peaking at day 3, median (Q1-Q3) 4452 (3645-5466) mmol l-1, and was positively correlated to the intake of parenteral lipids. Overall, infants displayed common fatty acid trajectories over the study period. However, remarkable differences in fatty acid patterns were observed depending on whether levels were expressed in relative or absolute units. For example, the relative levels of many LCPUFAs, including DHA and AA, declined rapidly after birth while their absolute concentrations increased in the first week of life. For DHA, absolute levels were significantly higher compared to cord blood from day 1 until postnatal week 16 (p < 0.001). For AA, absolute postnatal levels were lower compared to cord blood from week 4 throughout the study period (p < 0.05). Conclusions: Our data show that parenteral lipids aggravate the postnatal loss of LCPUFAs seen in preterm infants and that serum AA available for accretion is below that in utero. Further research is needed
|
|
| 48. |
- Svensson, Per-Arne, 1969, et al.
(författare)
-
Non-alcohol substance use disorder after bariatric surgery in the prospective, controlled Swedish Obese Subjects study.
- 2023
-
Ingår i: Obesity (Silver Spring, Md.). - 1930-739X. ; 31:8, s. 2171-2177
-
Tidskriftsartikel (refereegranskat)abstract
- The goal of this study was to investigate whether bariatric surgery is associated with substance use disorder (SUD) with substances other than alcohol.The prospective, controlled Swedish Obese Subjects study enrolled 2010 patients with obesity who underwent bariatric surgery (gastric bypass n=265; vertical banded gastroplasty n=1369; gastric banding n=376) and 2037 matched control individuals receiving usual obesity care. Participants with SUD other than alcohol use disorder were identified using International Statistical Classification of Diseases (ICD) codes from the Swedish National Patient Register (covering treatment in hospital but not primary care). Those with a history of non-alcohol SUD were excluded. Median follow-up was 23.8years.During follow-up, non-alcohol SUD incidence rates per 1000 person-years with 95% CI were 1.6 (0.8-3.1), 0.8 (0.5-1.2), 1.1 (0.5-2.2), and 0.6 (0.4-0.8) for gastric bypass, vertical banded gastroplasty, gastric banding, and control individuals, respectively. Only gastric bypass was associated with increased incidence of non-alcohol SUD (adjusted hazard ratio 2.54 [95% CI: 1.14-5.65], p=0.022) compared with control participants.Gastric bypass surgery was associated with increased risk of non-alcohol SUD, and this should be considered in long-term postoperative care.
|
|
| 49. |
- Sørensen, Andreas T., et al.
(författare)
-
Altered chloride homeostasis decreases the action potential threshold and increases hyperexcitability in hippocampal neurons
- 2017
-
Ingår i: eNeuro. - 2373-2822. ; 4:6
-
Tidskriftsartikel (refereegranskat)abstract
- Chloride ions play an important role in controlling excitability of principal neurons in the central nervous system. When neurotransmitter GABA is released from inhibitory interneurons, activated GABA type A (GABAA) receptors on principal neurons become permeable to chloride. Typically, chloride flows through activated GABAA receptors into the neurons causing hyperpolarization or shunting inhibition, and in turn inhibits action potential (AP) generation. However, in situations when intracellular chloride concentration is increased, chloride ions can flow in opposite direction, depolarize neurons, and promote AP generation. It is generally recognized that altered chloride homeostasis per se has no effect on the AP threshold. Here, we demonstrate that chloride overload of mouse principal CA3 pyramidal neurons not only makes these cells more excitable through GABAA receptor activation but also lowers the AP threshold, further aggravating excitability. This phenomenon has not been described in principal neurons and adds to our understanding of mechanisms regulating neuronal and network excitability, particularly in developing brain and during pathological situations with altered chloride homeostasis. This finding further broadens the spectrum of neuronal plasticity regulated by ionic compositions across the cellular membrane.
|
|
| 50. |
|
|
