| 31. |
- Flodell, Sara
(författare)
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Structure and Dynamics of the Hepatitis B Virus Encapsidation Signal Revealed by NMR Spectroscopy
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes the study of the three-dimensional structure and dynamics of the hepatitis B virus (HBV) encapsidation signal, epsilon, by means of nuclear magnetic resonance (NMR) and mutational data. HBV replicates by reverse transcription of an RNA pregenome into the viral DNA genome, which becomes enclosed in viral particles (encapsidation). Epsilon is a stem-loop structure within the RNA pregenome and both the primary sequence and secondary structure of epsilon are strongly conserved, in agreement with its essential function of propagating HBV. Epsilon is therefore a potential target for drug design. Studying the structure of epsilon requires development of new methods in the field of structural biology, as it is such a large RNA. Knowing the structure of epsilon will help to better understand the encapsidation mechanism and priming step of reverse transcription. This will help us in the search for antiviral drugs that block epsilon and prevent the viral reverse transcriptase from binding. NMR spectroscopy is a method that provides detailed structural and dynamical data in solution under natural conditions. However, the size of the molecules that can be studied with NMR is limited. NMR spectra become more and more difficult to interpret as the size of the molecule increases. To circumvent this problem, large RNA molecules can be divided into smaller parts and only the parts essential for NMR studies are selected. The information obtained from these smaller fragments can then be used to determine the structure of the larger molecule. Furthermore, a new method of enzymatically synthesizing nucleoside triphosphates with isotopes suitable for NMR has made it possible to specifically label the RNA molecules. Using this method it is possible to derive highly detailed molecular structures of RNA up to a size of 150 nucleotides. The method of selective isotope labelling was applied to different parts of HBV epsilon. Three RNA fragments of 27 (apical loop), 36 (internal bulge) and 61 (whole epsilon) nucleotides (nt) were synthesized in the unlabelled form. The 27-nt and 36-nt RNAs were also synthesized with (13C, 15N, 1', 3', 4', 5', 5"-2H5)-labelled uridines. The 61-nt sequence was (13C, 15N)-guanidine labelled. This labelling allowed unambiguous assignment of otherwise inaccessible parameters. The unlabelled and labelled RNA sequences provided the necessary data for structure derivation of the whole epsilon. The apical loop of epsilon forms a pseudo-triloop motif. There is only one conformation of the loop that fulfils all the restraints, including experimental chemical shifts. However, the loop adopts several structures that fulfil the experimental distance, torsion angle and residual dipolar coupling restraints. This may reflect true flexibility. Indeed, relaxation studies on the unlabelled and labelled 27-nt sequences show that the residues that show multiple conformations are flexible. This can be an important feature for the recognition and subsequent binding of epsilon to the viral polymerase. The information gained on the HBV encapsidation signal is useful in our understanding of the initiation of replication of the virus. This can in turn contribute to the search for drugs against HBV.
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| 32. |
- Ghazinour, Mehdi, 1967-
(författare)
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Trauma and resiliency : a study of refugees from Iran resettled in Sweden
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Several single factors have been identified as related to coping with trauma and as protective factors. Several studies emphasize the importance of personality, core beliefs, coping strategies and social support. However little attention has been paid to resiliency. The aim of the study was to identify some determinants of an individual’s resiliency after experienced traumatic life events, and to address the issue of its relationship to personality characteristics, psychopathology, coping resources and strategies, social support, sense of coherence and quality of life. In the present study, a convenience sample of 100 Iranian refugees, 66 males and 34 females in the age range of 18-65 were investigated. All the subjects have experienced one or several traumatic life events as soldiers, political prisoners or have been victims of torture or have escaped from the country in a stressful way. At the time of the present investigation the mean time living in Sweden was for male subject’s 12.8 years and for female 11.8. Nine instruments were administered during individual sessions, Temperament, Character Inventory (TCI), The EMBU (Swedish acronym for own memories concerning upbringing), The Symptom Checklist-90-Revised (SCL-90 – R), Beck Depression Inventory (BDI), Interview Schedule of Social Interaction (ISSI), Coping Resources Inventory (CRI), The Dysfunctional Attitude Scale (DAS), WHOQoL Group, 1995 (WHOQoL-100), The Sense of Coherence Scale (SoC). Several significant associations were found between personality temperament and character, parental rearing and psychopathology. When experiences of parental rearing were investigated in relation to psychopathology, male subjects scored high on parental rejection and were also more depressed compared to females. Although the individuals in the sample suffered from depression or anxiety, there were individuals that had adapted them-self well with the new life in Sweden and its demands. Nineteen percent of subjects who had low harm avoidance and high self directedness received more social support, had better coping strategies, higher sense of coherence and finally a better quality of life. This dissertation underscores the importance of multiple indicators when trying to understand resiliency. Personality traits, parental rearing, coping resources, social support and sense of coherence were the strongest predictors for resiliency. Having a systemic perspective helps to explain why some individuals are healthy and resilient despite traumatic life events, escaping from home country, applying for asylum, establishing a new home, learning new languages, to study and stablish and develop new bonds.
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| 33. |
- Guo, Dongsheng
(författare)
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The Identification and Characterisation of LRIG Gene Family and Its Expression in Astrocytic Tumours
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Gliomas are the most common primary brain tumours, and their capacity to invade surrounding normal brain prevents complete removal of the tumour. Malignant glioma has still a poor prognosis. However, with the rapid development of molecular biology our understanding about glioma has increased dramatically. Among known growth factors, EGF and its receptor are frequently amplified and over expressed in malignant glioma. Therefore, it is of interest to find approaches to hamper the activity of EGF/EGFR. The aim of this thesis was to identify and characterize human analogues to a recently identified gene in Drosophilia, kekkon-1, which negatively regulates the activity of Drosophilia EGF receptor. In the first part, we set up a quantitative real-time RT-PCR assay, which showed good linearity, reproducibility and uniformity. We analyzed the expression of the most commonly used reference genes, and showed that 18S was the most reliable endogenous reference gene in this study. In the second part, we cloned, identified, and sequenced a gene family, which we named leucine-rich repeats and immunoglobulin–like domains family (LRIG). The LRIG gene family had three vertebrate paralogs and one homolog in ascidiacea. The proteins encoded by human LRIG genes shared an overall structure with a signal peptide, 15 tandems leucine-rich repeats with N- and C- terminal flanking regions followed by 3 immunoglobulin-like domains, a transmembrane domain, and a cytoplasmic tail. Northern blot showed the mRNA sizes to be 5.5 kb for LRIG1, 4.8 kb for LRIG2, and 5.1 kb for LRIG3. LRIG1-3 mRNAs were detected in all human and mouse tissues analyzed, however, at various levels. FISH and BLAST analysis showed that LRIG1 was located at 3p14, LRIG2 at 1q13, and LRIG3 at 12q13. LRIG1 was shown to be down-regulated in several cancer cell lines and proposed to be a tumour suppressor gene. In the third part, we analysed the expression of LRIG gene family in human astrocytic tumours. LRIG1-3 mRNAs were detected in all human glioma cell lines, in primary tumour tissues and control-matched normal brain tissues, at various levels. Subcellular localizations of LRIG1-GFP fusion proteins were visualized in nuclear, perinuclear, and cytoplasmic compartment. According to the predicted protein sequences, short peptides were synthesized and used to raise antibodies in rabbits. The antibodies were used for immunohistochemical analysis of LRIG1-3 in 404 human astrocytic tumours in a tissue micro array. The pattern of immunoreactivity of LRIG1-3 was heterogeneous with staining in nuclear, perinuclear and cytoplasmic compartment of positive tumour cells. Perinuclear staining of LRIG1-3 displayed a significant inverse correlation with WHO grade and especially positive LRIG3 perinuclear and cytoplasmic staining correlated with a low proliferation index. The LRIGs correlated with survival, and LRIG3 perinuclear staining was in addition to tumour grade an independent prognostic factor. The results suggest that LRIGs may play a role in normal tissue, and may be of importance in the pathogenesis and prognosis of tumours. The exact function of LRIG1-3 remains to be established.
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| 34. |
- Gussing, Fredrik
(författare)
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Zonal organization of the mouse olfactory systems
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Animals survey their environment for relevant odorous chemical compounds by means of the olfactory system. This system is in most vertebrates divided into a main and accessory olfactory system with two specialized neuroepithelia, the olfactory and the vomeronasal epithelium, respectively. The sensory neurons reside in these epithelia and together the neurons have an extraordinary sensitivity and are capable of detecting a vast number of different chemical molecules. After processing the chemical information, behavior may be altered. The information about a chemicals structure is deconstructed into a format that the brain may process. This is facilitated by organizing sensory neurons into a map and that the individual neuron responds only to one chemical feature. The sensory maps appear to have zones with different neuronal subpopulations. This thesis is addressing the fact that establishment, maintenance and function of these zones are unknown.We identify a gene (NQO1) to be selectively expressed in defined zone of the olfactory and the vomeronasal epithelia, respectively. NQO1-positive and negative axons segregate within the olfactory nerve and maintain a zonal organization when reaching olfactory bulb target neurons. These results indicate that one zone of both the accessory and the main olfactory projection maps is composed of sensory neurons specialized in reducing environmental and/or endogenously produced quinones via an NQO1-dependent mechanism.In addition, we have identified genes expressed in a graded manner that correlates with the dorsomedial-ventrolateral zonal organization of the olfactory epithelia. Considering the known functions of identified genes in establishment of cell specificity and precise axonal targeting, we suggest that zonal division of the primary olfactory systems is maintained, during continuous neurogenesis, as a consequence of topographic counter gradients of positional information.The vomeronasal sensory neurons (VSN) are organized into an apical and a basal zone. The zones differ in expression of e.g. chemosensory receptor families and Gα protein subunits (Gαi2 and Gαo). We have analyzed transgenic mice (OMP-dnRAR) in which the VSNs are unresponsive to the function of one of the genes identified herein (RALDH2). The phenotype observed suggests that endogenous produced retinoic acid is selectively required for postnatal survival of neurons in the Gαo-positive zone. Analyses of another mouse line target deleted in the Gαi2 gene (Gαi2 mutant) reveal a cellular phenotype that is opposite to that of OMP-dnRAR mice. Consequently in these mice, the apical Gαi2-positive zone is reduced whereas VSNs in the basal zone are not affected.Several social and reproductive behaviors are under the influence of the vomeronasal organ. We have analyzed some behavioral consequences of having deficient neurons that corresponds to either of the two zones. We propose that cues important for aggressive behavior are detected by apical vomeronasal zone, while cues detected by both apical and basal VSNs influence gender preference behavior.
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| 35. |
- Hallberg, Magnus, 1974-
(författare)
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Studies of Functional Interactions within Yeast Mediator and a Proposed Novel Mechanism for Regulation of Gene Expression
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The yeast Mediator complex is required for transcriptional regulation both in vivo and in vitro and the identification of similar complexes from metazoans indicates that its function is conserved through evolution. Mediator subunit composition and structure is well characterized both by biochemical, genetic and biophysical methods. In contrast, little is known about the mechanisms by which Mediator operates and how the complex is regulated. The aim of my thesis was to elucidate how Mediator functions at the molecular level and to investigate functional interactions within Mediator. It is possible to recruit RNA polymerase II to a target promoter and thus to activate transcription by fusing Mediator subunits to a DNA binding domain. In order to investigate functional interactions within Mediator, we made such fusion proteins where different Mediator subunits were fused to the DNA binding domain of lexA. The expression of a reporter gene containing binding sites for lexA was subsequently measured in both a wild type strain and in strains where genes encoding specific Mediator subunits had been disrupted. We found that lexA-Med2 and lexA-Gal11 are strong activators that function independently of all Mediator subunits tested. On the other hand, lexA-Srb10 is a weak activator that depends on Srb8 and Srb11 and lexA-Med1 and lexA-Srb7 are both cryptic activators that become active in the absence of Srb8, Srb10, Srb11, or Sin4. Both lexA-Med1 and lexA-Srb7 proteins showed a stable association with the Mediator subunits Med4 and Med8 in wild type cells and in all deletion strains tested, indicating that they were functionally incorporated into the Mediator complex. We also showed that both Med4 and Med8 exist in two forms that differed in electrophoretic mobility and that these forms differed in their ability to associate with Mediator immuno-purified from the LEXA-SRB7 and LEXA-MED1 strains. Dephosphorylation assays of purified Mediator indicated that the two mobility forms of Med4 corresponded to the phosphorylated and unphosphorylated forms of the Med4 protein respectively. Some of the data presented in this study as well as previous genetic and biochemical data obtained in our lab suggested a functional link between the Med1, Med2, Srb10 and Srb11 proteins. We extended these findings by showing that the Srb10 kinase phosphorylates the Med2 protein at residue serine 208, both in vitro and in vivo. We also showed that a point mutation of the single phosphorylation site to an alanine or to an aspartic acid residue altered the gene expression of a specific set of genes. Taken together, these data indicate that posttranslational modification of Mediator subunits is a so far uncharacterized mechanism for regulation of gene expression. In order to study the function of the Srb7 subunit of Mediator, we isolated a temperature sensitive strain where the amino acids 2 to 8 of srb7 were deleted. The Mediator subunits Nut2 and Med7 were isolated as high copy suppressor of srb7-∆(2-8) and we were also able to show that Srb7 interacted with Nut2 and Med7 both in a 2-hybrid system and in co-immuno precipitation experiments using recombinantly expressed proteins. Interestingly, a deletion of amino acids 2 to 8 of Srb7 abolishes its interaction with both Med7 and Nut2 in vitro. Med4 also interacted with Srb7 in the 2-hybrid system and surprisingly, the first eight amino acids of Srb7 were shown to be sufficient for this interaction.
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| 36. |
- Hang, Hoang Minh, 1959-
(författare)
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Epidemiology of unintentional injuries in rural Vietnam
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main objective of this epidemiological study was to assess the incidence of unintentional non-fatal injuries, together with their determinants and consequences, in a defined Vietnamese population, thus providing a basis for future prevention. A one-year follow-up survey involved four quarterly cross-sectional household injury interviews during 2000. This cohort study was based within a demographic surveillance site in Bavi district, northern Vietnam, which provides detailed, longitudinal information in a continuous and systematic way. Findings relate to three phases of the injury process: before, during and after injury. The study showed that unintentional non-fatal injuries were an important health problem in rural Vietnam. The high incidence rate of 89/1000 pyar reflected almost one tenth of the population being injured every year. Home injuries were found to be most common, often due to a lack of proper kitchens and dangerous surroundings in the home. Road traffic injuries were less common but tended to be more severe, with longer periods of disability and higher unit costs compared with other types of injury. The leading mechanisms of injury were impacts with other objects, falls, cuts and crushing. Males had higher injury incidence rates than females except among the elderly. Elderly females were often injured due to falls in the home. Being male or elderly were significant risk factors for injury. Poverty was a risk factor for injuries in general and specifically for home and work related injuries, but not for road traffic injuries. The middle income group was at higher risk of traffic injuries, possibly due to their greater mobility. Injuries not only affected people’s health, but were also a great financial burden. The cost of an injury, on average, corresponded to approximately 1.3 months of earned income, increasing to 7 months for a severe injury. Ninety percent of the economic burden of injury fell on households, only 8% on government and 2% on health insurance agencies. Self-treatment was the most common way of treating injuries (51.7%), even in some cases of severe injury. There was a low rate of use of public health services (23.2%) among injury patients, similar to private healthcare (22.4%). High cost, long distances, residence in mountains, being female and coming from ethnic minorities were barriers for seeking health services. People with health insurance sought care more, but the coverage of health insurance was very low. Some prevention strategies might include education and raising awareness about the possible dangers of injury and the importance of seeking appropriate care following injury. To avoid household hazards, several strategies could be used: better light in the evening, making gravel paths around the house, clearing moss to avoid slipping, wearing protective clothing when using electrical equipment and improving kitchens. Similarly, improving road surfaces, having separate paths for pedestrians and cyclists and better driver training could reduce road accidents. In Vietnam, and especially in a rural district without any injury register system, a community-based survey of unintentional injuries has been shown to be a feasible approach to injury assessment. It gave more complete results than could have been obtained from facility-based studies and led to the definition of possible prevention strategies.
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| 37. |
- Hartini, Theresia Ninuk Sri, 1953-
(författare)
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Food habits, dietary intake and nutritional status during economic crisis among pregnant women in Central Java, Indonesia
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- FOOD HABITS, DIETARY INTAKE AND NUTRITIONAL STATUS DURING ECONOMIC CRISIS AMONG PREGNANT WOMEN IN CENTRAL JAVA, INDONESIA Th. Ninuk Sri Hartini, Epidemiology and Public Health Sciences, Dept. of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden; Community Health and Nutrition Research Laboratories, Gadjah Mada University, Jogjakarta, Indonesia; Nutrition Academy, Ministry of Health, Jogjakarta, Indonesia ABSTRACT Objectives: The overall objective of this thesis was to study the effect of the economic crisis on food habits, dietary intake and nutritional status among pregnant women in Purworejo District, Central Java, Indonesia. Subjects and methods: Since 1994, the Community Health and Nutrition Research Laboratories (CHN-RL), Gadjah Mada University, Jogjakarta, Indonesia have operated a surveillance system in Purworejo District, Central Java, Indonesia. Between 1996 and 1998, a monthly monitoring of new pregnancies took place within the surveillance system. This project included a detailed evaluation of dietary intake during pregnancy. Each trimester six repeated 24-hour recalls were conducted on 450 pregnant women. Weight and mid-upper arm circumference (MUAC) were measured monthly, height and serum ferritin concentration was measured once. Here, the dietary intake and nutritional status of the women during the second trimester are evaluated in relation to the emergence of the economic crisis, that started in 1997. Women were classified into four socio-economic groups. A computer program (Inafood) was developed to calculate nutrient intake. To support the quantitative results, a qualitative study was carried out between January and June 1999. Focus group discussions were held with four groups of women, in-depth interviews with 16 women, three traditional birth attendants and four midwives, and observations were carried out with four women. Here, food habits and coping strategies in relation to the economic crisis were explored. Results: Before the crisis, more than 80% of the pregnant women had inadequate energy and 40% had inadequate protein and vitamin A intake. All women had inadequate calcium and iron intake. The food intake consisted of rice, nuts and pulses and vegetables, meaning that it was mainly plant-based food. Rice behaved as a strongly inferior good in economic term, meaning that its consumption increased in spite of its price increase. Rice remained an important supplier of energy, protein and carbohydrates also during the crisis. Especially, rural, poor women with access to rice fields increased their rice intake and decreased their intake of non-rice staple foods. Reasons for the continued rice intake included the women had been accustomed to eating rice since they were born and that cooking methods for non-rice staple foods were difficult. The intake of animal food was low initially and decreased further during the economic crisis. Rich women decreased their intake of fat. The intake of nuts and pulses and vegetables increased for most groups. Nuts and pulses were an important supplier of calcium and iron, and vegetables were an important supplier of vitamin A. The rural, poor women with access to rice fields kept their food taboos also during the crisis. Rich women were able to maintain a good nutrient intake during the crisis, although fat intake decreased. Also, urban poor and rural, poor, landless women had an increased intake “during crisis” because relatives and neighbour provided some foods and perhaps also because of the government support programme. Conclusion: Before the crisis, energy and nutrient intake of pregnant women were inadequate. The food pattern of the women was predominately plant-based. Rich women were able to maintain a good nutrient intake during the crisis, although fat intake decreased. Rural poor women with access to rice fields had a higher rice intake than other groups throughout the crisis. Urban poor and rural poor, landless women experienced a decreased intake of most nutrients in the transition period but an increased intake during the crisis, reflecting government intervention and support from relatives and neighbours. The latter, however, is not sustainable. Thus, vulnerable groups are at risk of developing nutritional deficiencies without food support programmes. Key words: Food intake, nutrient intake, nutritional status, food pattern, pregnancy, food habits, coping strategies, economic crisis, Indonesia.
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| 38. |
- Hedberg, Ylva, 1975-
(författare)
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Cell Cycle Regulation in Human Renal Cell Carcinoma
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ABSTRACTCell cycle regulation in human renal cell carcinomaYlva Hedberg, Departments of Medical Biosciences, Pathology, and Surgical andPerioperative Sciences, Urology Andrology, Umeå University, SwedenDeregulated growth control is a hallmark of neoplasia potentially caused by aberrant expression of cell cycle regulatory proteins. The importance of such aberrations in human renal cell carcinoma (RCC) has not been fully clarified. Therefore, the protein expressions of several G1/S regulatory proteins in human RCC were evaluated and their relation to clinico-pathological data was examined.Western blotting and immunohistochemistry were used to detect the proteinexpression of cyclin D1, D3, and E in 80 RCCs. Most tumors expressed higher levels of cyclin D1 (75%) and cyclin E (65%) compared to corresponding normal kidney cortex. In contrast, only 16 % of the tumors had high levels of cyclin D3. In conventional RCCs, low levels of cyclin D1 were associated with large tumor size, aneuploidy and a poor outcome for the patients. High expression of cyclin D3 and Ewere associated with aneuploidy, high proliferation, high TNM-stage, and high nuclear grade. Cyclin E was positively correlated to cyclin D3 but inversely associated with cyclin D1. Cyclin D3 and E were not associated with survival. The majority of RCCs had normal p27 levels, determined by immunohistochemistry, whereas the few tumors with low p27 levels were associated with large tumor size and poor survival.In order to confirm and extend our initial studies, a tissue microarray consisting of 218 RCCs was constructed and cyclin D1, D3, E, p27 were detected by immunohistochemistry. The tissue microarray results were validated by comparing the array data with western analyzes. Due to the large number of tumors analyzed we could evaluate potential differences in expression patterns of cell cycle regulators between conventional, papillary, and chromophobe RCCs. Interestingly, the protein expression differed between RCC types, showing that the conventional tumors generally had high cyclin D1 expression. In contrast, papillary and chromophobe RCCs had high cyclin E expression. Downregulation of p27 was found mostly in chromophobe RCCs. The retinoblastoma protein (pRb) was detected in all RCCs. Phosphorylation of pRb, detected by western blotting or immunohistochemistry and phospho-specific antibodies, was observed in approximately 50% of the tumors. The cdk-inhibitor p16 was not overexpressed suggesting that pRb was functional in the majority of RCCs.In summary, abnormal expression of G1-cyclins and the CDK-inhibitor p27 was common in RCC whereas the main G1/S-substrate, pRb, seemed to be functional. The aberrations further differed between the separate RCC subtypes and were linked to clinical behavior.
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| 39. |
- Henriksson, Maria, 1971-
(författare)
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Cellular targets of Pseudomonas aeruginosa toxin Exoenzyme S
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pseudomonas aeruginosa is an opportunistic pathogen that can cause life-threatening infections in immunocompromised patients. It uses a type III secretion dependent mechanism to translocate toxic effector proteins directly into the eukaryotic cell. The enzymatic activity of two of these toxins, Exoenzyme S (ExoS) and Exoenzyme T (ExoT), have been studied in this thesis. ExoS is a bi-functional toxin known to contain a C-terminal ADP-ribosyltransferase activity, which has been shown to modify members of the Ras family in vitro. The N-terminal of ExoS contains a GTPase Activating Protein (GAP) domain, which shows specificity towards Rho proteins in vitro. ExoT shows high homology (76%) towards ExoS and has also been reported to contain ADP-ribosyltransferase activity in vitro. To study the biological effect of the two toxins, we inserted ExoS or ExoT into eukaryotic cells using the heterologous type III secretion system of Yersinia pseudotuberculosis. We found that Ras was ADP-ribosylated in vivo and this modification altered the ratio of GTP/GDP bound directly to Ras. We also found that ExoS could ADP-ribosylate several members of the Ras superfamily in vivo, modulating the activity of those proteins. In contrast, ExoT showed no ADP-ribosylation activity towards any of the GTPases tested. This suggests that ExoS is the major ADP-ribosyltransferase modulating small GTPase function encoded by P. aeruginosa. Furthermore, we have demonstrated that the GAP activity of ExoS abolishes the activation of RhoA, Cdc42 and Rap1 in vivo, and that ExoT shows GAP activity towards RhoA in vitro.The ADP-ribosyltransferase activity of ExoS is dependent on the eukaryotic protein 14-3-3. 14-3-3 proteins interact with ExoS in a phospho-independent manner. We identified the amino acids 424DALDL428 on ExoS to be necessary for the specific interaction between ExoS and 14-3-3. Deletion of these five amino acids abolishes the ADP-ribosylation of Ras and hence the cytotoxic effect of P. aeruginosa on cells. Thus the 14-3-3 binding motif on ExoS appears to be critical for both the ADP-ribosylation activity and the cytotoxic action of ExoS in vivo.
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| 40. |
- Hoeyer, Klaus, 1972-
(författare)
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Biobanks and informed consent : An anthropological contribution to medical ethics
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: 1985 saw the beginnings of a population-based biobank in Västerbotten County, Sweden. In 1999, a start-up genomics company, UmanGenomics, obtained ‘all commercial rights’ to the biobank. The company introduced an ethics policy, which was well received in prestigious journals, focusing on public oversight and informed consent. Aims: To explore how social anthropology can aid understanding of the challenges posed by the new role of the biobank in Västerbotten, and thus complement more established traditions in the field of medical ethics. An anthropological study of the ethics policy was executed. Theoretical perspective: Inspired by the anthropology of policy and social science perspectives on ethics and morality, the policy was studied at three analytical levels: policymakers (who formulate the policy), policy workers (who implement the policy, primarily nurses who obtain informed consent) and target group (for whom and on whom the policy is supposed to work: the potential donors to the biobank). Methods: Policymakers, nurses, and potential donors were interviewed, donations observed, and official documents analysed to mirror the moral problematizations made at the three levels in each other and to study the practical implications of the policy. To extend the reliability of the findings two surveys were executed: one among the general population, one among donors. Results: The qualitative studies show that policymakers distinguish between blood and data differently to potential donors. Informed consent seems more important to policymakers than potential donors, who are more concerned about political implications at a societal level. Among the respondents from the survey in the general public, a majority (66.8%) accepted surrogate decisions by Research Ethics Committees; a minority (4 %) stated informed consent as a principal concern; and genetic research based on biobank material was generally accepted (71%). Among the respondents to the survey in donors, 65% knew they had consented to donate a blood sample, and 32% knew they could withdraw their consent; 6% were dissatisfied with the information they had received; and 85% accepted surrogate decisions by Research Ethics Committees. Discussion: The ethics policy constitutes a particular naming and framing of moral problems in biobank-based research which overemphasises the need for informed consent, and underemphasises other concerns of potential donors. This embodies a political transformation where access to stored blood and medical information is negotiated in ethical terms, while it also has unacknowledged political implications. In particular, the relations between authorities and citizens in the Swedish welfare state are apparently transforming: from mutual obligation to individual contracts. Conclusion: Anthropology contributes to medical ethics with increased awareness of the practical implications of particular research ethical initiatives. This awareness promotes appreciation of the political implications of ethics policies and raises new issues for further consideration.
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