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- Ekmark Lewén, Sara, 1978-
(författare)
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Cellular Reactions and Behavioral Changes in Focal and Diffuse Traumatic Brain Injury : A Study in the Rat and Mouse
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traumatic brain injury (TBI) is a severe condition and a major cause of death and disability. There is no pharmacological treatment available in clinical practice today and knowledge of brain injury mechanisms is of importance for development of neuroprotective drugs. The aims of the thesis were to get a better understanding of astrocyte reactions and immune responses, as well as behavioral changes after focal unilateral cortical contusion injury and diffuse bilateral central fluid percussion injury in rats and mice.In the focal injury models, the astrocyte reactions were generally restricted to the ipsilateral hemisphere. After diffuse TBI, vimentin and glial fibrillary acidic protein (GFAP) positive reactive astrocytes were bilaterally expressed in brain regions even distant from the injury site, including regions where axonal injury was seen. Early after diffuse TBI, there was a robust immune response, including activation of macrophages/microglia (Mac-2+) and infiltration of neutrophils (GR-1+) and T-cells (CD3+).In order to measure functional outcome, the recently established Multivariate Concentric Square Field™ (MCSF) test for complex behaviors, including risk taking and explorative strategies was used. The Morris water maze (MWM) was applied for testing learning and memory. The MCSF test revealed alterations in risk taking, risk assessment and exploratory behavior, in the mice subjected to focal injury whereas mice subjected to the diffuse injury showed a deviant stereotyped behavior. After focal injury mice showed a decreased ability to adapt to the arena in the second trial, when tested repeatedly in the MCSF test. Mice subjected to diffuse injury had an impaired memory but not learning, in the MWM test. Post-injury treatment with the anti-inflammatory anti-interleukin-1β (IgG2 a/k) antibody showed a positive effect on functional outcome in the diffuse injury model. Altogether, the results demonstrate that focal and diffuse TBI models produce differences in cellular reactions and behavioral outcome and that the immune response plays a key role in the pathology after brain injury.
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| 3. |
- Trolle, Carl, 1985-
(författare)
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Stem Cell Transplantation in Dorsal Root Injury
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- After traumatic injuries to the brachial plexus there is a risk that one or more of the spinal roots are torn from the spinal cord, known as avulsion injury. This often leads to paralysis and chronic pain, notoriously difficult to treat with current pharmacotherapy. Surgical treatment may improve motor function but sensory recovery is usually poor as sensory axons fail to establish functional connections inside the spinal cord. The aims of this thesis were to develop a model for dorsal root avulsion in rodents in order to investigate the potentials of stem cell therapy for enhancing sensory regeneration after spinal root avulsion. Two different types of stem cells, embryonic and neural crest stem cells, have been transplanted to the avulsion model and analysed using immunohistochemical methods. The results indicate that stem cells survive after transplantation to the avulsed dorsal root and associate with regenerating axons. Furthermore, the different stem cells display different phenotypes after transplantation where embryonic stem cells give rise to neurons located outside the spinal cord that could serve as projection neurons whereas the neural crest stem cells form elongated tubes outlining the avulsed dorsal root and are associated with regenerating neuronal fibers. We have also discovered that the neural crest stem cells migrate into the damaged spinal cord as single cells. The neural crest stem cells also display a diversity in generating both neuronal and glial cells that may have different beneficial effects in neural repair following dorsal root avulsion. To improve the survival of stem cell transplants, the potentials of co-transplanting embryonic stem cells together with nanoparticle delivered growth factor mimetics has been investigated. The results indicate that nanoparticle delivered growth factors improve both transplant survival and maturation in comparison to untreated controls and may be a promising strategy in stem cell transplantation.
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| 4. |
- Wisén, Niclas, et al.
(författare)
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Are Peacekeeping Missions Inevitably Stressful?
- 2021
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Ingår i: Scandinavian Journal of Military Studies. - : Scandinavian Military Studies. - 2596-3856. ; 4:1, s. 210-219
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Wisén, Niclas, et al.
(författare)
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Is conduct after capture training sufficiently stressful?
- 2022
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Ingår i: Frontiers in Psychology. - : Frontiers Media SA. - 1664-1078. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Conduct after capture (CAC) training is for personnel at risk of being captured. To be effective, it needs to be stressful. But how do we know if it is stressful enough? This study uses biomarkers and cognitive measures to evaluate CAC. Soldiers undergoing CAC were measured by the stress hormone cortisol from saliva samples at baseline and during training. The training consisted of being taken capture and put through a number of realistic and threatening scenarios, targeting survival strategies taught in the preceding week. Between scenarios, the trainees were held in a holding cell where they were monitored by a guard. The saliva samples were taken in conjunction with the scenarios. The whole training took place over a period of ~24 h. Cognitive performance was measured at baseline and after training. Three groups took part Group A (n = 20) was taken after 48 h of intense tasks leaving them in a poor resting state. Group B (n = 23) was well rested at CAC onset. Group C (n = 10) was part of a survival, evasion, resistance, and escape (SERE) instructor course. The CAC training was the same for all groups. Group A exhibited a high increase in cortisol during CAC, compared to baseline levels were multiple times as high as “expected” values. Group B exhibited elevated levels slightly lower than those of group A, they also “dropped” to “normal” levels during the latter part of the exercise. Group C displayed the least increase with only slightly elevated levels. CAC training is stressful and cortisol levels were elevated enough to satisfy the prerequisite for effective stress inoculation. No cognitive performance drop could be identified; however, several participants “froze” during the exercise due to intensive stress.
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| 6. |
- Wisén, Niclas, et al.
(författare)
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Measuring the impact of operational stress : The relevance of assessing stress-related health across the deployment cycle
- 2023
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Ingår i: Military medicine. - : Oxford University Press (OUP). - 0026-4075 .- 1930-613X. ; 188:7-8, s. 2126-2132
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Mental health issues from intense or prolonged stress are a common concern in regard to military deployment. Deployments can objectively vary in stress exposure, but it is the individuals' perception of that stress that affects sustainability, mental health, and combat fitness, which calls for the need of a protocol to evaluate and maintain a current estimation of stress impact. So, how can we assess the impact of stressors during different phases of deployment?Materials and methods: We used three psychological self-rating forms, the PSS14-Perceived Stress Scale, SMBM-Shirom Melamed Burnout Measure, and KSQ-Karolinska Sleep Questionnaire, to measure the impact of stress before (T1), during (T2), and at homecoming (T3). We also wanted to see if T1 or T2 results could predict T3 results to be able to better prepare the homecoming program.The forms were handed out to Swedish soldiers deployed in Mali in 2017. The forms were collected as a way to assess the status of the mental health load at three timepoints based on the personnel function as a way to assess the current "psychological fitness level".Results: The results show that stress measured using PSS14 was high at homecoming. The same result was observed for SMBM. No measures from T1 or T2 could however predict the T3 results.Conclusions: Taken together, we found that screening of all contingent staff is relatively easy and provides personnel with relevant data on mental health and stress at the current time. We also found that test results correlated between T1 and T2 but not with T3. This indicates that there might be different stressors that affect staff at different timepoints.
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