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| 2. |
- Kjellström, Anna, et al.
(författare)
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Barnen på Tibrandsholm
- 2009
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Ingår i: Västerhus. - Stockholm : Kungl. Vitterhets Historie och Antikvitets Akademin. - 9789174023848 ; , s. 236-243
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Kjellström, Ulrika, et al.
(författare)
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Dose-related changes in retinal function and PKC-alpha expression in rabbits on vigabatrin medication : Effect of vigabatrin in the rabbit eye.
- 2009
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Ingår i: Graefe's Archive for Clinical and Experimental Ophthalmology. - : Springer Science and Business Media LLC. - 1435-702X .- 0721-832X. ; 247:8, s. 1057-1067
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: To investigate, in a rabbit model, the effect of two different doses of vigabatrin (VGB) on retinal function and morphology. METHODS: Twenty-nine rabbits of mixed strain were divided into two groups, receiving either high-dose (n = 15) or low-dose (n = 14) oral VGB treatment (cumulative dose 29.8 +/- 2.9 g and 14.2 +/- 0.6 g respectively). Ten rabbits receiving water served as control animals. The rabbits underwent three baseline ff-ERG measurements before initiation of VGB medication and two ff-ERG registrations during treatment, after 8 and 12-14 weeks respectively. At the end of the study, the expression of protein kinase C-alpha (PKC-alpha), gamma amino butyric acid (GABA) A receptors, vimentin, glial fibrillary acidic protein (GFAP) and peanut agglutinin (PNA) was examined in retinal sections from all rabbits. RESULTS: In animals of the high-dose group, the ff-ERG measurements revealed a significant decrease of isolated rod b-wave amplitudes, combined rod-cone b-wave amplitudes and amplitudes of oscillatory potentials (OPs); OP1, OP2 and OP3. In the low-dose group, the b-wave amplitudes of combined rod-cone responses as well as OP2 and OP3 were significantly reduced. PKC-alpha labeling demonstrated a dose-related translocation of the enzyme in rod bipolar cells, also revealing a significant decline of the number of PKC-alpha labeled rod bipolar cells in treated animals. Vimentin labeling showed a dose-related deviant labeling pattern of Müller cells, with strikingly low labeling intensity in the outer parts of the cells; in the outer limiting membrane (OLM) as well as the outer nuclear layer (ONL). Labeling with antibodies against GABA A receptors and GFAP, as well as PNA staining, revealed no differences between treated animals and controls. CONCLUSIONS: In this study, VGB medication was associated, in a dose-related manner, with a decrease of ff-ERG amplitudes as well as with altered protein expression in rod bipolar cells and Müller cells, suggesting alterations of inner retinal function. The dose-related morphological and electrophysiological changes indicate a retinal pathology that may explain the constricted visual fields seen in some patients treated with VGB.
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| 4. |
- Kjellström, Ulrika, et al.
(författare)
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Full-field ERG and visual fields in patients 5 years after discontinuing vigabatrin therapy.
- 2008
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Ingår i: Documenta Ophthalmologica. - : Springer Science and Business Media LLC. - 1573-2622 .- 0012-4486. ; 117, s. 93-101
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Tidskriftsartikel (refereegranskat)abstract
- Purpose In numerous studies vigabatrin medication has been associated with visual field constriction and alterations in the full-field electroretinogram (ff-ERG), but it is not clear whether these changes are reversible or not. The purpose of this study was to examine patients with visual field loss and reduced ff-ERG several years after discontinuing vigabatrin therapy, in order to investigate reversibility. Methods Eight patients with visual field constriction and reduced cone responses measured by 30 Hz flicker ERG were examined with Goldmann perimetry and ff-ERG 4-6 years after discontinuing medication. The results were compared with investigations conducted during medication, 4-6 years previously. Statistical analysis was also used to compare the ff-ERG results of the patients, during treatment and at follow-up, with a group of 70 healthy subjects. Results Visual field constriction remained 4-6 years after discontinuing vigabatrin therapy. The amplitude of the 30 Hz flicker response also remained reduced on follow-up both compared with the results during treatment and with the control group. Moreover, the amplitude of the isolated rod response and the combined rod-cone response were decreased in the patients compared with the control group, during vigabatrin treatment as well as on follow-up. On follow-up, oscillatory potentials (OPs) also were registered, showing reduced amplitudes in patients compared with controls. The within subject comparison showed no significant changes. Conclusion Vigabatrin attributed visual field constriction and reduced ff-ERG responses remain several years after discontinuing vigabatrin therapy, indicating drug-induced permanent retinal damage.
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| 5. |
- Ning, Tong, 1975, et al.
(författare)
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Atmospheric Water Vapor Content Inferred From GPS Data and Compared to a Global NWP Model and a Regional Climate Model
- 2008
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Ingår i: 2008.10.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Radio based space geodetic methods are affected by the water vapor in the atmosphere.The velocity of the propagating signal is reduced, depending on the value of the refractiveindex. The atmospheric water vapor content, sometimes also called Integrated WaterVapor (IWV), can be inferred from the estimated propagation delay, or the excess propagationpath often expressed in units of length. The observations are relative measurementsof time, which makes the methods interesting from a calibration point of view - since timeis the physical parameter that we can measure with the highest accuracy.Since water vapor is difficult, and costly, to measure with a high temporal and spatialresolution, given its characteristics of variability, researchers in the atmospheric scienceshave shown interest in using data from already existing ground-based continuously operatingGPS receivers. Time series of the IWV from specific sites are now longer than tenyears. For example, 20 sites in the Swedish GPS network have produced continuous datasince 1993/1994. In addition to GPS also additional global navigational satellite systems(GNSS), such as the European Galileo and the finalization of the Russian GLONASS, willin the future significantly improve the spatial sampling of the atmosphere, and also reducethe relative influence of orbit errors for individual satellites.We have analyzed ground-based GPS data acquired in Europe and Africa over the period2001-2006. IWV results from the GPS data analysis are compared to the global NumericalWeather Prediction (NWP) models from the European Center for Medium RangeWeatherForecasting (ECMWF) as well as the regional climate model of the Rossby Center.The overall goal for the possible use of GNSS data in climate research is to determine towhich extent these independent data can be used to discriminate between different climatemodels - both in terms of absolute values as well as long term trends - thereby improvingthe quality of the models and increasing the probability to produce realistic scenarios ofthe future climate.
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