Search

I samband med avregleringen av den svenska postmarknaden är PostNord AB ett företag som de senaste decennierna stått inför många utmaningar. Syftet med denna studie är att studera PostNords interna styrning under en större omorganisation. Detta sker i dagsläget inom PostNords verksamhet i samband med omstruktureringen av enheterna för distribution av paket och pallgods i Stockholmsområdet och vi har därför valt att basera vår studie på denna process. För att uppfylla syftet har vi genomfört ett flertal kvalitativa intervjuer, vilka även har underbyggts av företagets offentliga och interna dokument. Genom att använda oss av en teoretisk referensram med utgångspunkt i nyinstitutionell teori och organisationskommunikation framträder en bild av fallföretagets interna styrning. Med utgångspunkt i vår tolkning blir slutsatsen att PostNord är ett företag som genom rationella förändringar klarar av att anpassa sig till en föränderlig omvärld. Därmed kommer de troligtvis även i fortsättningen att behålla sin starka position på den svenska postmarknaden., PostNord AB is a company that in recent decades has faced many challenges becuase of the changes in market demands evolving from the reformation of the Swedish Postal Service. The purpose of this study is to investigate an organization’s internal management during a major reorganization. The focus of this paper is the current process in which PostNord is reconstructing their facilities of distribution for parcels and goods in the Stockholm area. To reach our aims for this paper we conducted a number of interviews, which in turn has been supported by the company's public and internal documents. Through the use of a theoretical framework based on new institutionalism and organizational communication emerges an understanding of the company's internal management. Based on our interpretations we draw the conclusion that PostNord is an organisation that will continue to thrive with their abillity to adapt and make rational decisions in a continously changing environment.

The human thioredoxin system has a wide range of functions in cells including regulation of cell proliferation and differentiation, immune system modulation, antioxidant defense, redox control of transcription factor activity, and promotion of cancer development. A key component of this enzymatic system is the selenoprotein thioredoxin reductase 1 (TrxR1), encoded by the TXNRD1 gene. Transcription of TXNRD1 involves alternative splicing, leading to a number of transcripts also encoding isoforms of TrxR1 that differ from each other at their N-terminal domains. Here we have studied the TXNRD1_v3 isoform containing an atypical N-terminal glutaredoxin (Grx) domain. Expression of the transcript of this isoform was found predominantly in testis but was also detected in ovary, spleen, heart, liver, kidney, and pancreas. By immunohistochemical analysis in human testis with antibodies specific for the Grx domain of TXNRD1_v3, the protein was found to be predominantly expressed in the Leydig cells. Expression of the TXNRD1_v3 transcript was also found in several cancer cell lines (HCC1937, H23, A549, U1810, or H157), and in HeLa cells, it was induced by estradiol or testosterone treatments. Surprisingly, green fluorescent protein fusions with the complete TXNRD1_v3 protein or with only its Grx domain localized to distinct cellular sites in proximity to actin, and furthermore, had a potent capacity to rapidly induce cell membrane protrusions. Analyses of these structures suggested that the Grx domain of TXNRD1_v3 localizes first in the emerging protrusion and is then followed into the protrusions by actin and subsequently by tubulin. The results presented thus reveal that TXNRD1_v3 has a unique and distinct expression pattern in human cells and suggest that the protein can guide actin polymerization in relation to cell membrane restructuring.

Adjuvant treatment with adriamycin has been suggested to improve results after liver transplantation for hepatocellular cancer. Here we have applied an animal model for evaluation of treatment with adriamycin and/or cyclosporine A on liver tumour growth. Three chemically induced rat liver tumours with various degree of differentiation were transferred to the spleens of syngenic rats. Each recipient group was divided into four subgroups, treated with adriamycin and/or cyclosporine A or none of the drugs. When the tumour was well differentiated no proliferation was found in any of the subgroups. When the tumour exhibited a more pronounced dysplasia, adriamycin stimulated tumour growth. This effect was further increased by cyclosporine. In the animals transplanted with the most aggressive tumour, adriamycin inhibited tumour growth. When given together with cyclosporine this inhibition was counteracted. These data suggest that adriamycin, especially when given together with cyclosporine, may have a stimulatory effect on liver tumour cell growth.

This thesis concerns the role of ubiquinone, the only endogenously synthesised lipid soluble antioxidant, in the cellular defence against peroxidation of proteins and lipids. The aims of the present investigations were to study the biosynthesis of ubiquinone in two different organelle fractions, i.e. microsomes and peroxisomes and to characterise the enzyme reactions of the three flavoenzymes, hpoamide dehydrogenase, glutathione reductase and thioredoxin reductase in the reduction of ubiquinone. A semipreparative HPLC method was established to rapidly isolate different polyprenols with high purity. The isolated compounds could be used for studies of different enzyme reactions in the mevalonate pathway, and as standards for quantitative HPLC-analysis. Compared to conventional chromatographic methods this new technique was much more rapid and polyprenols with higher purity was isolated. It was demonstrated that both peroxisomes and microsomes were involved in the biosynthesis of ubiquinone. Two enzymes involved in the synthesis of ubiquinone, trans-prenyltransferase and nonaprenyl-4-hydroxybenzoate (NPHB)-transferase, were investigated. The results clearly showed differences in the regulation of the synthesis of ubiquinone in those organelles. The specific activity of trans-prenyltransferase in peroxisomes was 30% of the total activity found in both organelles. The characteristics of the regeneration of ubiquinol by the flavoenzymes, hpoamide dehydrogenase, glutathione reductase and thioredoxin reductase were investigated. These enzymes belong to the same family of enzymes and are defined as homodimeric pyridine nucleotide-disulfide oxidoreductases. The reduction of ubiquinone by Hpoamide dehydrogenase and glutathione reductase was shown to be highly elevated by addition of zinc to the reaction mixture, whereas this reaction by thioredoxin reductase was inhibited by zinc. For Hpoamide dehydrogenase and glutathione reductase the pH optimum for the reaction was found at

Ubiquinol is a powerful antioxidant, which is oxidized in action and needs to be replaced or regenerated to be capable of a sustained effort. This article summarises current knowledge of extramitochondrial reduction of ubiquinone by three flavoenzymes, i.e. lipoamide dehydrogenase, glutathione reductase and thioredoxin reductase, belonging to the same pyridine nucleotide-disulfide oxidoreductase family. These three enzymes are the most efficient extramitochondrial ubiquinone reductases so far described. The reduction of ubiquinone by lipoamide dehydrogenase and glutathione reductase is potently stimulated by zinc and the highest rate of reduction is achieved at acidic pH and the rates are equal with either NADPH or NADH as co-factors. The most efficient ubiquinone reductases are mammalian cytosolic thioredoxin reductases, which are selenoenzymes with a number of biological functions. Reduction of ubiquinone by thioredoxin reductase is in contrast to the other two enzymes investigated, inhibited by zinc and shows a sharp physiological pH optimum at pH 7.5. Furthermore, the reaction is selenium dependent as revealed from experiments using truncated and mutant forms of the enzyme and also in a cellular context by selenium treatment of transfected thioredoxin reductase overexpressing stable cell lines. The reduction of ubiquinone by the three enzymes offers a multifunctional system for extramitochondrial regeneration of an important antioxidant.