| 1. |
- Aaseth, J, et al.
(author)
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Prevention of progression in Parkinson's disease
- 2018
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In: Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine. - : Springer Science and Business Media LLC. - 1572-8773. ; 31:5, s. 737-747
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Journal article (peer-reviewed)
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| 2. |
- Aaseth, Jan, et al.
(author)
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Treatment strategies in Alzheimers disease: a review with focus on selenium supplementation
- 2016
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In: Biometals. - : SPRINGER. - 0966-0844 .- 1572-8773. ; 29:5, s. 827-839
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Journal article (peer-reviewed)abstract
- Alzheimers disease (AD) is a neurodegenerative disorder presenting one of the biggest healthcare challenges in developed countries. No effective treatment exists. In recent years the main focus of AD research has been on the amyloid hypothesis, which postulates that extracellular precipitates of beta amyloid (A beta) derived from amyloid precursor protein (APP) are responsible for the cognitive impairment seen in AD. Treatment strategies have been to reduce A beta production through inhibition of enzymes responsible for its formation, or to promote resolution of existing cerebral A beta plaques. However, these approaches have failed to demonstrate significant cognitive improvements. Intracellular rather than extracellular events may be fundamental in AD pathogenesis. Selenate is a potent inhibitor of tau hyperphosphorylation, a critical step in the formation of neurofibrillary tangles. Some selenium (Se) compounds e.g. selenoprotein P also appear to protect APP against excessive copper and iron deposition. Selenoproteins show anti-inflammatory properties, and protect microtubules in the neuronal cytoskeleton. Optimal function of these selenoenzymes requires higher Se intake than what is common in Europe and also higher intake than traditionally recommended. Supplementary treatment with N-acetylcysteine increases levels of the antioxidative cofactor glutathione and can mediate adjuvant protection. The present review discusses the role of Se in AD treatment and suggests strategies for AD prevention by optimizing selenium intake, in accordance with the metal dysregulation hypothesis. This includes in particular secondary prevention by selenium supplementation to elderly with mild cognitive impairment.
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| 3. |
- Andersen, Oluf, 1941, et al.
(author)
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Diffusion tensor imaging in multiple sclerosis at different final outcomes
- 2018
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In: Acta Neurologica Scandinavica. - : Hindawi Limited. - 1600-0404 .- 0001-6314. ; 137:2, s. 165-173
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Journal article (peer-reviewed)abstract
- OBJECTIVES:Methods to evaluate the relative contributions of demyelination vs axonal degeneration over the long-term course of MS are urgently needed. We used magnetic resonance diffusion tensor imaging (DTI) to estimate degrees of demyelination and axonal degeneration in the corpus callosum (CC) in cases of MS with different final outcomes.MATERIALS AND METHODS:We determined DTI measures mean diffusivity (MD), fractional anisotropy (FA), and axial (AD) and radial (RD) diffusivities in the CC of 31 MS patients, of whom 13 presented a secondary progressive course, 11 a non-progressive course, and seven a monophasic course. The study participants were survivors from an incidence cohort of 254 attack-onset MS patients with 50 years of longitudinal follow-up. As reference, we included five healthy individuals without significant morbidity.RESULTS:In patients with secondary progression, compared to all other groups, the corpus callosum showed increased RD and reduced FA, but no change in AD. None of the parameters exhibited differences among non-progressive and monophasic course groups and controls.CONCLUSION:Increased RD was observed in secondary progressive MS, indicating significant myelin loss. Normal RD values observed in the clinically isolated syndrome and non-progressive groups confirm their benign nature. AD was not a characterizing parameter for long-term outcome. Demyelination revealed by increased RD is a distinguishing trait for secondary progression.
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| 8. |
- Edvinsson, Lars, et al.
(author)
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Neuropeptides in cerebrospinal fluid of patients with Alzheimer's disease and dementia with frontotemporal lobe degeneration
- 1993
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In: Dementia (Switzerland). - 1013-7424. ; 4:3-4, s. 71-167
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Journal article (peer-reviewed)abstract
- The two major primary degenerative dementias, dementia of Alzheimer type (DAT) and frontal lobe degeneration of non-Alzheimer type (FLD) have several clinical features in common but also many symptoms that differ. In a clinical material of 80 patients with either of the two forms of dementia (DAT = 39, FLD = 41) we have studied the levels of neuropeptides in the cerebrospinal fluid (CSF) in order to find biochemical markers for CNS affection. The dementia forms were evaluated by careful clinical analysis, psychometric testing and measurement of regional cerebral blood flow. Approximately one third of the subjects died during the completion of the study and neuropathology was performed, confirming the diagnoses. We observed reductions in the CSF levels of antidiuretic hormone and somatostatin in both DAT and FLD. A strong tendency to reduction was noted for neuropeptide Y (NPY). There was a correlation with the duration of disease demonstrating a significant reduction in NPY levels in subjects with DAT. Most notably there was a strong reduction in the levels of delta sleep inducing peptide (DSIP) in DAT cases only. The levels of DSIP in FLD were the same as in controls. The reverse was found for corticotropin releasing factor (CRF) which had a significant reduction in FLD patients but not in those with DAT. The present study indicates a difference in the CSF levels of neuropeptides, observations that these may serve as biochemical markers which differentiate DAT and FLD.
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| 9. |
- Essén, Hanno
(author)
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The exact Darwin lagrangian
- 2007
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In: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 79:6
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Journal article (peer-reviewed)abstract
- Darwin (1920) noted that when radiation can be neglected it should be possible to eliminate the radiation degrees of freedom from the action of classical electrodynamics and keep the discrete particle degrees of freedom only. Darwin derived his well-known Lagrangian by series expansion in v/c keeping terms up to order (v/c)(2). Since radiation is due to acceleration the assumption of low speed should not be necessary. A Lagrangian is suggested that neglects radiation without assuming low speed. It cures deficiencies of the Darwin Lagrangian in the ultra-relativistic regime.
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| 10. |
- Galvez, Edelmira D., et al.
(author)
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Heap leaching of caliche minerals : Phenomenological and analytical models - Some comparisons
- 2012
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In: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 33, s. 46-53
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Journal article (peer-reviewed)abstract
- Antofagasta, Chile, has one of the most important deposits of saltpetre in the world, which is called caliche. These deposits are mainly composed of nitrate, halite, sodium anorthite, and quartz. Minor species include anhydrite, glauberite, loeweite, calcite, polyhalite, probertite, and gypsum. Recently, several operations began to use heap leaching for the extraction of saltpetre. Modelling the heap leaching of caliche is not straightforward because of the many minerals and their different dissolution rates. Moreover, caliche may have a large fraction of soluble minerals, approximately 40%, which causes the heap to slump. In this work, we present two models. The first, which is a phenomenological model, is an extension of the model published by Valencia et al. (2008). The system is modelled as a column comprised of N small columns, and in each of these small columns, the height of the solids varies with time when the soluble minerals are dissolved. The liquid in each small column has the same composition (well-stirred reactor). The second model, which is an analytical model, is an extension of that published by Mellado et al. (2009) for low-grade minerals, such as copper and gold, which considers that the leaching phenomenon occurs on different scales of size and time. However, in this work, the time scale at the particle level is based on the Bruner and Tolloczko dissolution model. The objective of this work is to test the suitability of the analytical model as a tool for use in optimisation, for which the model needs to be solved many times. The phenomenological model was used to generate simulated experimental data. The results show that the analytical model may be a useful tool in optimisation.
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