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- Ehinger, Magnus, et al.
(författare)
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Influence of CD4 or CD8 deficiency on collagen-induced arthritis
- 2001
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Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 103:3, s. 291-300
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Tidskriftsartikel (refereegranskat)abstract
- The role of T cells in the mouse collagen-induced arthritis (CIA) model for rheumatoid arthritis is not clarified, and different results have been reported concerning the role of CD4 and CD8 T cells. To address this issue, we have investigated B10.Q mice deficient for CD4 or CD8. The mice lacking CD4 were found to be less susceptible to disease, but not completely resistant, whereas the CD8 deficiency had no significant impact on the disease. No difference in the development of late occurring relapses was noted. Interestingly, the CD4-deficient mice had a severely reduced response to the glycosylated form of the immunodominant type II collagen (CII) 256–270 peptide whereas the response to the non-glycosylated peptide was not significantly different. Furthermore, CD4-deficient mice had lower antibody responses to CII, explaining the lower disease susceptibility. In comparison with previously reported results, it is apparent that the lack of CD4 molecules has a different impact on CIA if present on different genetic backgrounds, findings that could possibly be related to the occurrence of different disease pathways of CIA in different mouse strains.
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| 2. |
- Johannesson, Mikael
(författare)
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Geometric Models of Similarity
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation examines and discusses some phenomena related to the geometric representation of similarity. It takes its inspiration from the existing body of empirical research within the fields of perceptual and cognitive psychology, but also connects to certain areas of machine learning. The problems discussed concern the modelling of information integration behavior when concepts like asymmetry, integrality, separability and familiarity are taken into account. The dissertation investigates how these phenomena can be modelled using geometric representations in order to increase the descriptive power of the models. The main conclusions that can be drawn from this dissertation are that the descriptive powers of geometric models can be increased in a number of ways: a) By augmenting traditional geometric models with parameters of prominence they can reflect asymmetric similarity at least as well as previously known asymmetric models which include more parameters. b) Some specific metric, for instance, the Euclidean metric, should not be used merely by tradition. If there is reason to believe that there are groupings of dimensions such that the most descriptive metric differs between groups, the distance may be better described with a combination rule adding the contribution of each group/subspace together. c) Aspects of familiarity with stimuli should be taken into consideration, even for familiarity built up during a short period of time. When taking familiarity into consideration it may be possible to describe information integration over time with a finer granularity. Furthermore, by focusing on the part of the phenomenological data that reflect a more stable behavior, which seems to occur first when subjects are sufficiently familiar with the stimuli, the more stable behavior can be more accurately described.
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| 3. |
- Johannesson, Mikael
(författare)
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The Problem of Combining Integral and Separable Dimensions
- 2001
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- For geometrical models of cognition, the notion of distance rules - or metrics - is fundamental. Within psychology, it is well established that pairs of dimensions that are processed holistically - integral dimensions - normally combine so as they are best described with a Euclidean metric, whereas pairs of dimensions that are processed analytically - separable dimensions - most often combine with a city-block metric. The experimental tradition studying information integration has typically been limited to two-dimensional stimuli. A next step is to study information integration when dealing with more complex stimuli. This step give rise to several interesting questions regarding information integration behaviour, especially when both integral and separable pairs are included. For example: How do we integrate information when both integral and separable pairs are involved? This paper extends earlier research regarding information integration in that it deals with stimuli with more than two dimensions, and with complex stimuli consisting of both dimensional pairs previously identified as holistic, and dimensional pairs previously identified as analytical. The general pattern identified is that information integration can be more accurately described with a rule taking aspects of stimuli into consideration compared to a traditional rule. For example, it appears that combinations of analytical and holistic stimuli, are better described by treating the different subspaces individually and then combining these with addition, compared to any single Minkowskian rule, and much better compared to any of the Minkowskian rules traditionally used (i.e. the city-block-, the Euclidean or the dominance-metrics).
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