| 1. |
- Degerman, Sofie, et al.
(författare)
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Long Leukocyte Telomere Length at Diagnosis Is a Risk Factor for Dementia Progression in Idiopathic Parkinsonism
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- Telomere length (TL) is regarded as a marker of cellular aging due to the gradual shortening by each cell division, but is influenced by a number of factors including oxidative stress and inflammation. Parkinson's disease and atypical forms of parkinsonism occur mainly in the elderly, with oxidative stress and inflammation in afflicted cells. In this study the relationship between blood TL and prognosis of 168 patients with idiopathic parkinsonism (136 Parkinson's disease [PD], 17 Progressive Supranuclear Palsy [PSP], and 15 Multiple System Atrophy [MSA]) and 30 controls was investigated. TL and motor and cognitive performance were assessed at baseline (diagnosis) and repeatedly up to three to five years follow up. No difference in TL between controls and patients was shown at baseline, nor any significant difference in TL stability or attrition during follow up. Interestingly, a significant relationship between TL at diagnosis and cognitive phenotype at follow up in PD and PSP patients was found, with longer mean TL at diagnosis in patients that developed dementia within three years.
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| 2. |
- Domellof, Magdalena Eriksson, et al.
(författare)
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The relation between cognition and motor dysfunction in drug-naive newly diagnosed patients with parkinson's disease
- 2011
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Ingår i: Movement Disorders. - New York, N.Y. : Raven Press. - 0885-3185 .- 1531-8257. ; 26:12, s. 2183-2189
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have reported cognitive decline to be common in the early phase of Parkinson's disease. Imaging data connect working memory and executive functioning to the dopamine system. It has also been suggested that bradykinesia is the clinical manifestation most closely related to the nigrostriatal lesion. Exploring the relationship between motor dysfunction and cognition can help us find shared or overlapping systems serving different functions. This relationship has been sparsely investigated in population-based studies of untreated Parkinson's disease. The aim of the present study was to investigate the association between motor signs and cognitive performance in the early stages of Parkinson's disease before the intake of dopaminergic medication. Patients were identified in a population-based study of incident cases with idiopathic parkinsonism. Patients with the postural instability and gait disturbances phenotype were compared with patients with the tremor-dominant phenotype on demographics and cognitive measures. Associations between cognitive and motor scores were investigated, with age, education, and sex controlled for. Bradykinesia was associated with working memory and mental flexibility, whereas axial signs were associated with episodic memory and visuospatial functioning. No significant differences in the neuropsychological variables were found between the postural instability and gait disturbances phenotype and the tremor phenotype. Our results indicate a shared system for slow movement and inflexible thinking that may be controlled by a dopaminergic network different from dopaminergic networks involved in tremor and/or rigidity. The association between axial signs and memory and visuospatial function may point to overlapping systems or pathologies related to these abilities.(C) 2011 Movement Disorder Society
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| 3. |
- Domellöf, Magdalena Eriksson, 1977-
(författare)
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Cognitive and motor dysfunction in the early phase of Parkinson's disease
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Parkinson’s disease (PD) is a chronic and progressive neurodegenerative disease. The diagnosis is based on a combination of the motor signs: tremor, bradykinesia, rigidity and postural abnormalities. Mild Cognitive Impairment (MCI) is common early in the disease and a large proportion of patients with PD develop dementia (PDD). Associations between motor symptoms and cognitive decline have been suggested but the results are inconclusive due to differences in the selection of participants and variables tested. Large population based studies with comprehensive neuropsychological investigation in newly diagnosed cases with PD followed prospectively are rare. The aim of this thesis was to improve characterization and understanding of cognition in PD, and to explore the relationship to motor impairment in the early phase of PD.Methods: All new patients with suspected idiopathic parkinsonism in the catchment area (142 ooo inhabitants) were examined during a period of five years and four months. Among other investigations, a comprehensive neuropsychological evaluation was carried out in 119 of 148 patients with PD together with 30 age matched healthy controls. Assessments were repeated after one three and five years.Results: Patients performed worse than healthy controls in a majority of neuropsychological tests. MCI at the time of diagnosis were found in 36% according to recently published MCI criteria. Thirty % were cognitively impaired using another definition. One fourth of the patients developed PDD within five years after diagnosis and 25 % of those with MCI at baseline reversed back to normal cognition. Age and MCI were significant predictors of dementia. Education was an independent predictor for severe cognitive dysfunction at diagnosis but did not predict PDD. Patients with MCI converting to PDD had worse performance on visuospatial function, semantic fluency, episodic memory, mental flexibility and conceptual thinking. There were no differences in cognitive performance between patients with predominant Postural and Gait Disturbances (PIGD) and the tremor dominant subtype at the baseline investigation and belonging to the PIGD subgroup at baseline did not predict PDD. Dementia converters declined more rapidly than non-converters in posture/gait function. Associations between bradykinesia and measures of executive functions and working memory were found, and between posture and gait disturbances and visuospatial function. Some of these associations were persistent after one year. Patients receiving the dopamine agonist pramipexole performed significantly worse on a measure of verbal fluency at the one year follow up.Conclusions: The differences in proportions of cognitively impaired in the different studies emphasize the value of joint criteria for PD-MCI. Even when using such criteria, a substantial proportion of patients revert back to normal function. The increase in motor disability in patients with PDD could have several different causes that need to be further investigated. Associated motor and cognitive dysfunctions could reflect common pathophysiological processes in partly shared networks. Both dopaminergic and non-dopaminergic motor and cognitive functions seems to be involved in PDD which suggests that pharmacological treatment in PD needs to go beyond the scope of dopaminergic deficiency in search for new therapies that would also be effective for non-motor symptoms.
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| 4. |
- Domellöf, Magdalena E, et al.
(författare)
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Persistence of associations between cognitive impairment and motor dysfunction in the early phase of Parkinson's disease
- 2013
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Ingår i: Journal of Neurology. - : Springer Berlin/Heidelberg. - 0340-5354 .- 1432-1459. ; 260:9, s. 2228-2236
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Tidskriftsartikel (refereegranskat)abstract
- The relation between cognitive and motor functions in Parkinson's disease is not fully understood. In an incidence population of newly diagnosed drug na < ve patients with Parkinson's disease, associations were found between the degree of bradykinesia and postural instability and gait disturbances, measured by the Unified Disease Rating Scale, and different types of cognitive functions. To investigate the stability of these associations over time, we explored the association of differences between baseline and 1-year follow-up in 91 incident cases with Parkinson's disease. The magnitude of change between the two assessments was assessed together with analysis of differences based on which dopaminergic medication was used. Change in bradykinesia was associated with change in working memory and mental flexibility. Changes in postural instability and gait disturbances were associated with change in visuospatial memory. A negative effect of the dopamine agonist pramipexole on phonemic fluency performance was found compared to treatment with other dopaminergic drugs. Change in cognitive and motor functions were associated from time of diagnosis until 1 year after diagnosis. These persisting findings strengthen results from a previous cross-sectional study suggesting similar associations. The effects of dopamine agonists on phonemic fluency should be investigated further.
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| 5. |
- Ekman, Urban, et al.
(författare)
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Longitudinal changes in task-evoked brain responses in Parkinson's disease patients with and without mild cognitive impairment
- 2014
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Ingår i: Frontiers in Neuroscience. - : Frontiers. - 1662-4548 .- 1662-453X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Cognitive deficits are common in Parkinson's disease. Previous cross-sectional research has demonstrated a link between cognitive impairments and fronto-striatal dopaminergic dysmodulation. However, longitudinal studies that link disease progression with altered task-evoked brain activity are lacking. Therefore, our objective was to longitudinally evaluate working-memory related brain activity changes in Parkinson's disease patients with and without mild cognitive impairment (MCI). Patients were recruited within a longitudinal cohort study of incident patients with idiopathic parkinsonism. We longitudinally (at baseline examination and at 12-months follow-up) compared 28 patients with Parkinson's disease without MCI with 11 patients with Parkinson's disease and MCI. Functional MRI blood oxygen level dependent signal was measured during a verbal two-back working-memory task. Patients with MCI under-recruited bilateral medial prefrontal cortex at both time-points (main effect of group: p < 0.001, uncorrected). Critically, a significant group-by-time interaction effect (p < 0.001, uncorrected) was found in the right fusiform gyrus, indicating that working-memory related activity decreased for patients with Parkinson's disease and MCI between baseline and follow-up, while patients without MCI were stable across time-points. The functional connectivity between right fusiform gyrus and bilateral caudate nucleus was stronger for patients without MCI relative to patients with MCI. Our findings support the view that deficits in working-memory updating are related to persistent fronto-striatal under-recruitments in patients with early phase Parkinson's disease and MCI. The longitudinal evolution of MCI in Parkinson's disease translates into additional task-evoked posterior cortical changes.
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| 6. |
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| 7. |
- Forsgren, Eva, et al.
(författare)
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Comparative virulence of Nosema ceranae and Nosema apis in individual European honey bees
- 2010
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Ingår i: Veterinary Parasitology. - : Elsevier BV. - 0304-4017 .- 1873-2550. ; 170, s. 212-217
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Tidskriftsartikel (refereegranskat)abstract
- Nosema apis and Nosema ceranae are intracellular microsporidian parasites infecting the midgut epithelial cells of adult honey bees. N. ceranae was considered to be restricted to the Asian honey bee, Apis cerana, but is nowadays a parasite found also in the European honey bee (Apis mellifera)across most of the world. Recent surveys and experimental work suggest that N. ceranae is a serious threat to the global beekeeping industry. It has been suggested that N. ceranae induces significantly higher mortality in honey bees than N. apis, but little is known about their comparative virulence. In this study, we used in vivo infection experiments to study the two parasites' different virulence (i.e. multiplication rate and infectivity). A qPCR was developed to elucidate within host competition between the two parasites using mixed infections. The outcome of the experiments indicates minor differences in infectious dose and multiplication rate between the two species. Moreover, the mortality caused by N. ceranae was not significantly higher than for N. apis and N. ceranae appeared to have no competitive advantage within host. (C) 2010 Elsevier B.V. All rights reserved.
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| 8. |
- Forsgren, Eva
(författare)
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Diversity of honey stores and their impact on pathogenic bacteria of the honeybee, Apis mellifera
- 2014
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 4, s. 3960-3967
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Tidskriftsartikel (refereegranskat)abstract
- Honeybee colonies offer an excellent environment for microbial pathogen development. The highest virulent, colony killing, bacterial agents are Paenibacillus larvae causing American foulbrood (AFB), and European foulbrood (EFB) associated bacteria. Besides the innate immune defense, honeybees evolved behavioral defenses to combat infections. Foraging of antimicrobial plant compounds plays a key role for this social immunity behavior. Secondary plant metabolites in floral nectar are known for their antimicrobial effects. Yet, these compounds are highly plant specific, and the effects on bee health will depend on the floral origin of the honey produced. As worker bees not only feed themselves, but also the larvae and other colony members, honey is a prime candidate acting as self-medication agent in honeybee colonies to prevent or decrease infections. Here, we test eight AFB and EFB bacterial strains and the growth inhibitory activity of three honey types. Using a high-throughput cell growth assay, we show that all honeys have high growth inhibitory activity and the two monofloral honeys appeared to be strain specific. The specificity of the monofloral honeys and the strong antimicrobial potential of the polyfloral honey suggest that the diversity of honeys in the honey stores of a colony may be highly adaptive for its social immunity against the highly diverse suite of pathogens encountered in nature. This ecological diversity may therefore operate similar to the well-known effects of host genetic variance in the arms race between host and parasite.
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| 9. |
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| 10. |
- Forsgren, Eva
(författare)
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European foulbrood in honey bees
- 2010
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Ingår i: Journal of Invertebrate Pathology. - : Elsevier BV. - 0022-2011 .- 1096-0805. ; 103, s. S5-S9
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Tidskriftsartikel (refereegranskat)abstract
- European foulbrood (EFB) is a severe bacterial brood disease caused by the Gram-positive bacterium Melissocccus plutonius. The disease has a worldwide distribution and is an increasing problem in some areas. Although the causative agent of EFB was described almost a century ago, many basic aspects of its pathogenesis are still unknown. This review presents both historical results and recent molecular data to synthesize present knowledge of this enigmatic honey bee disease. (C) 2009 Elsevier Inc. All rights reserved.
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