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- Rollman, Ola, et al.
(författare)
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Platelet derived growth factor (PDGF) responsive epidermis formed from human keratinocytes transduced with the PDGF beta receptor gene.
- 2003
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Ingår i: J Invest Dermatol. ; 120, s. 742-
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Tidskriftsartikel (refereegranskat)abstract
- Platelet-derived growth factor is a major proliferative and migratory stimulus for connective tissue cells during the initiation of skin repair processes. In response to injury, locally produced platelet-derived growth factor is secreted by a diversity of cutaneous cell types whereas target activity is confined to cells of mesenchymal origin, e.g. dermal fibroblasts and smooth muscle cells. Although epidermal cells contribute to cutaneous platelet-derived growth factor activity by their ample capacity to secrete platelet-derived growth factor ligand, normal epidermal keratinocytes are not known to express any member of the platelet-derived growth factor receptor family. In order to study if epidermis may be genetically transformed to a platelet-derived growth factor sensitive compartment we aimed to introduce the gene encoding human platelet-derived growth factor receptor beta (PDGF beta R) into epidermal keratinocytes using a retrovirus-derived vector. Successful gene transfer to primary cells was confirmed by immunofluorescence staining, southern blotting, and ligand-induced receptor autophosphorylation. By culturing a mixture of PDGF beta R-transduced and unmodified keratinocytes at the air-liquid interface on devitalized dermis, we were able to establish a multilayered epithelium showing histologic similarities to that evolved from native keratinocytes or keratinocytes transduced with the reporter gene encoding enhanced green fluorescent protein. Receptor-modified epidermal tissue cultured for 6 days and examined by immunofluorescence microscopy was shown to contain PDGF beta R-expressing keratinocytes distributed in all layers of living epidermis. By continued tissue culture in serum-containing medium, the epidermis became increasingly cornified although receptor-positive cells were still observed within the viable basal compartment. Stimulation of PDGF beta R-transduced epidermis with recombinant platelet-derived growth factor BB had a mitogenic effect as reflected by an increased frequency of Ki-67 positive keratinocytes. The study demonstrates that transgene expression of human PDGF beta R can be achieved in epidermal keratinocytes by retroviral transduction, and that ligand activation of such gene-modified skin equivalent enhances cell proliferation. In perspective, viral PDGF beta R gene transfer to keratinocytes may be a useful approach in studies of receptor tyrosine kinase mediated skin repair and epithelialization.
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- Eriksson, Göran
(författare)
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Den televiserade politiken : studier av debatt- och nyhetsjournalistik
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study takes as its point of departure the discussion around the mediazation of politics. The media are an essential part of, and play a crucial role for, the reproduction of a certain discourse that, within the field of Media and Communications research, has been branded a mediated or mediatized political discourse (Fairclough 1995a; Chouliaraki 2000; Ekström 2001 Ib). Television and TV journalism have been especially important for the development of this discourse (Dahlgren 1995; Thompson 1995). One aim of this dissertation is to investigate how TV journalism functions to establish, reproduce or transform a mediated political discourse, i.e. different ways of understanding and talking about politics and politicians. In order to understand these processes I am proposing an approach in which the analysis of text, text production and reception are intertwined. Thus, there is also a second aim, a methodological one, with this dissertation. The intent is to develop and test an approach in which the studies of text, text production and reception are integrated in one form of case study. This integrated approach is also meant to be applicable to other fields of investigation than that of my own study. Two case studies have been conducted within this frame. One study follows what I have branded a chronological design. The other follows a retrospective design. This approach is founded on the framework for Critical Discourse Analysis (CDA) as developed by Fairclough (1992; 1995a; 1995b). Fairclough suggests that the analysis of media discourse should be a multidimensional one: texts must be related to discourse practice – the practices of text production and text consumption – and to the sociocultural practice of which they are a part. In this work I will argue for an “extension” of Fairclough’s approach, i.e. an approach that, in the study of processes of text production and reception, incorporates ethnographic methods, in this case participant observation and interviews. To summarise the result of the different case studies, I make the following conclusion: (1) The day-to-day routinised forms of production and representation which characterises TV journalism as discourse practice can lead to the establishment of such discursive elements in the texts that bring forth negative images of politics. The communicative devices used in TV journalism establish functions in the texts that can have the potential of placing the citizens in a position of suspicion and distrust. Here, two conditions are of special importance. One concerns TV journalism’s beliefs and assumptions of what attracts TV viewers, and the other concerns TV journalism’s understanding of self. (2) Through the functions that they could carry, the texts produced by TV journalistic means reproduce a mediated political discourse that has a tendency to establish a distrustful position in relation to politics. When “offered” this position by TV journalism, it is easy for the citizens to start doubting the politicians’ motives and abilities. (3) A mediated political discourse works ideologically in such a way that it reproduces an image of politics which ultimately favours the position of TV journalism in society. It is through the incessant production of stories and narratives about its own institution, serving up an image of a profession and a practice useful to society (first and foremost as an investigator and a critic of the political institutions), that TV journalism can appear to be a useful institution in society. This is a position that TV journalism can maintain and reproduce by hiding its power to construct the world around it.
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| 5. |
- Forseth, Torbjörn, et al.
(författare)
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Thermal growth performance of juvenile brown trout Salmo trutta : no support for thermal adaptation hypotheses
- 2009
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 74:1, s. 133-149
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Tidskriftsartikel (refereegranskat)abstract
- Using thermal growth data from eight populations of anadromous and lake-feeding brown trout Salmo trutta, hypotheses of adaptation to local optima and countergradient variation in growth were tested. The adaptation to local optima hypothesis suggests that natural selection can shift optimal performance temperatures to match the prevailing temperature in a new or changed thermal niche. In contradiction, the countergradient variation hypothesis suggests that populations from hostile environments perform better than conspecifics from benign environments at all temperatures. In this study, growth capacity varied between populations but there was no significant correlation between any of the estimated thermal performance parameters (e.g. lower and upper thermal growth limits, optimal temperature for growth and maximum growth capacity) and natural climatic conditions among populations. Hence, S. trutta growth response to temperature lends no support for either of the two suggested thermal adaptation hypotheses. Instead, growth capacity among populations tended to correlate positively with female size at maturity.
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- Gustafsson, Jörgen, et al.
(författare)
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Utveckling och nuläge för Skandinavisk synrehabilitering
- 2009
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Ingår i: Optik. - 1653-3666. ; :12, s. 41-52
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med denna studie var att samla inuppgifter om likheter och skillnader i förhållandetill personal, budget för hjälpmedel,och organisationsstrukturen inomsynrehabiliteringen i de tre länderna Sverige,Danmark och Norge.
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