| 1. |
- Barral, Anna-Maria, 1963-
(författare)
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Immunological Studies in Malignant Melanoma : Importance of TNF and the Thioredoxin System
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Malignant melanoma is a tumor whose incidence is dramatically increasing in persons with light-coloured skin in all parts of the world. Due to its resistance against traditional chemo- and radiotherapy, melanoma has been a favourite target of alternative therapies, in particular those involving immunological mechanisms. Cytokines and particularly tumor necrosis factor (TNF) have been studied as possible antitumoral agents, but also as endogenous growth or differentiation factors. Previous studies showed that melanomas could express TNF in situ and that this expression correlated to decreased lymphocyte infiltration. On the other hand, redox reagents can modulate expression of cytokines, and the thioredoxin (Trx) system is particularly known to influence expression and secretion of TNF in vitro.The overall aim of this research was to explore immunological aspects of melanoma, particularly the role of TNF both in vitro and in vivo, as well as its possible modulation by Trx.In the in vitro studies first we developed a novel method for obtention of monoclonal antibodies against melanoma antigens, and generated and characterized specific monoclonal antibodies against both full-length and truncated Trx. We studied the cytokine expression of a panel of normal and transformed melanocytic cells by immunofluorescence, all of which presented TNF and Trx at levels comparable to monocytic cells, and TNF-receptors (TNFR) at low but detectable levels. Melanoma cells did not secrete TNF upon stimulation in spite of its presence in the Golgi apparatus. However, melanoma cells expressed the TNF-processing enzyme TACE and were capable of cleaving transfected GFP-tagged TNF. Imaging studies point to a possible cell-cell tranfer of endogenous TNF in melanoma cells.On the other hand, TNF and Trx expression in melanoma cell lines correlated to resistance against exogenous TNF. We studied then the in situ expression of TNF and Trx by immunohistochemistry in a group of 44 cutaneous melanoma patients. Trx expression did not correlated to survival or other clinicalpathological parameters. TNF expression significantly correlated to better survival in tumors thicker than 0,8 mm, and constituted an independent prognostic factor.These results point to a biological role of endogenous TNF in malignant melanoma, either by constituting an autocrine/paracrine differentiation factor or by modulating communication with other cell types, particularly of the host’s immune system.
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| 2. |
- Bergh, Ann-Charlotte, 1980-
(författare)
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Importance of microenvironment and antigen in the regulation of growth and survival of CLL cells
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chronic lymphocytic leukemia (CLL) cells rapidly die when put in culture implying that microenvironmental signals delivered by accessory cells confer CLL cells with a growth advantage. Recent findings show that CLL cells are antigen experienced and antigen binding play a critical role in the pathogenesis of the disease. The overall aim of this thesis was to study the influence of the microenvironment and antigen binding in CLL.In paper I, we studied the influence of the small redox-regulatory molecule thioredoxin (Trx) on CLL cell survival and proliferation. We found Trx to be highly expressed in CLL lymph nodes (LNs), secreted from stromal cells surrounding proliferating CLL cells in proliferation centers, indicating growth promoting properties. Secreted Trx was also shown to protect CLL cells from apoptosis.In paper II, oxidized LDL was added to subset #1 CLL cells. However, in contrast to our hypothesis, we could not observe activation and proliferation of CLL cells. Instead subset #1 CLL cells were unresponsive/anergic through the B cell receptor (BcR). This anergic state could however be overcome by “wash out” of bound antigen or addition of toll-like receptor 9 stimulation in some patients.Gene expression profiles differ between groups of CLL patients and in peripheral blood (PB) and LN compartment, due to different microenvironments. However, it is not known whether these differences also apply for DNA methylation. In paper III, we identified various genes that were alternatively methylated between IGHV mutated (M) and unmutated (UM) groups. For example prognostic genes, CLLU1 and LPL, genes involved in B cell signaling, IBTK, as well as numerous TGF-β and NF-κB/TNF pathway genes.The intensity and duration of BcR signals are fine-tuned by enhancing or inhibitory coreceptors. SHP-1 inhibits BcR-signals by dephosphorylation. In paper IV, we compared the expression and activity of SHP-1 in CLL cells from LN with matched PB samples. However, in contrast to our hypothesis, SHP-1 activity/phosphorylation status in PB and LN, did not differ significantly.This thesis, add another piece to the puzzle, on how the microenvironment and antigens influence CLL pathogenesis. Since great variations among individuals are seen, further studies in different groups of patients are necessary to elucidate the importance of antigen for the development of CLL.
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| 3. |
- de Alwis, Manudul Pahansen, 1980-
(författare)
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Towards consonance in working conditions, health and performance aboard high-performance marine craft
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The High-Performance Marine Craft (HPMC) is a complex man-machine system dealing with the stochastic nature of the sea. The occupants of these craft are challenged by the strenuous work environments resulting in various detrimental conditions and reducing the overall performance of the system. The sophisticated craft, designed and developed for high operational demands, are underused due to the human limitations while occupants confronting various psychophysical impairments. A balance is required between the craft and human to get the most out of the system as an ensemble. Achieving that, the knowledge is essential about the human response to the working conditions aboard HPMC which is lacking in the scientific community.In this context, a research program has been commenced to investigate working conditions aboard HPMC and the response of the craft occupants in terms of health and performance. The thesis presents the research as a holistic approach to integrate the exposure-response relationship into HPMC design and operation.An epidemiological study is designed and executed to identify and quantify the risk associated with the working conditions aboard HPMC. As the first step, two web-based questionnaire tools are developed, validated and pilot tested for cross-sectional and longitudinal investigation of health and performance in HPMC occupants. Then a sample of HPMC occupants is investigated for work-related and individual risk factors relating to their work-exposure, health and performance in a cross-sectional cohort study. The prevalence of health impairments and performance degradation is determined while estimating their association with work exposure. Following that, another sample of HPMC occupants is longitudinally examined in a prospective cohort study for their work exposure, health and performance estimating the incidence of adverse health effects and its association with the occupational exposure to shock and vibration. Finally, a method is developed for a decision support feedback system continuously updating the crew during real-time operations on the severity of expected high-intensity short-duration impacts as well as the accumulated vibration exposure aboard HPMC.The cross-sectional study shows that the prevalence of musculoskeletal pain (MSP) among HPMC occupants is comparatively high and that the exposure to severe conditions aboard semi-displacement and planing craft increases the risk of MSP. The latter also increases the risk of performance degradation. The longitudinal study indicates an incidence of MSP and performance degradation in HPMC occupants. It also suggests that the accumulation of occupational exposure to shock and vibration aboard HPMC is a factor increasing the risk of MSP incidence while quantifying the level of risk. The introduced method for real-time crew feedback is capable of capturing the exposure severity and informing it to the crew in a sufficiently short time.The research has successfully achieved the objectives. It has also highlighted the areas that need further improvements and suggested the domains that require extended investigations.
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| 4. |
- Eriksson, Anders, 1983-
(författare)
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Cathodic Arc Synthesis of Ti-Si-C-N Thin Films : Plasma Analysis and Microstructure Formation
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This Thesis explores the arc deposition process and films of Ti-Si-C-N, inspired by the two ternary systems Ti-Si-N and Ti-C-N, both successfully applied as corrosion and wear resistant films. The correlation between cathode, plasma, and film properties are studied for a comprehensive view on film formation. Novel approaches to adapt arc deposition to form multi-element films are investigated, concluding that the source of C is not a determining factor for film growth. Thus, cubic-phase films of similar properties can be synthesized from processes with either 1) ternary Ti-Si-C cathodes, including the Ti3SiC2 MAX phase, in N2 atmosphere or 2) Ti-Si cathodes in a mixture of N2 and CH4. With the Ti3SiC2 cathodes, superhard (45-50 GPa) cubic-phase (Ti,Si)(C,N) films can be deposited. The structure is nanocrystalline and feather-like, with high Si and C content of 12 and 16 at%, respectively. To isolate the effects of Si on film structure, magnetron sputtered Ti-Si-N films of comparatively low defect density was studied. These films show a strong preference for {200} growth orientation, and can be grown as a single phase solid solution on MgO(001) substrates up to ~9 at% Si, i.e. considerably higher than the ~5 at% Si above which a feather-like nanocrystalline structure forms in arc deposited films. On (011) and (111) growth surfaces, the films self-organize into TiN columns separated by segregated crystalline-to-amorphous SiNx. The conditions for film growth by arc were investigated through plasma studies, showing that plasma properties are dependent on cathode composition as well as phase structure. Plasma generation from Ti-Si cathodes, with up to 25 at% Si, show higher average ion charge states of Ti and Si compared to plasma from elemental cathodes, which may be related to TiSix phases of higher cohesive energies. The ion energy distributions range up to 200 eV. Furthermore, compositional discrepancies between plasma ions and film infer significant contributions to film growth from Si rich neutral species. This is further supported by depositions with a macroparticle filter, intended for growth of films with low surface roughness, where Si and C contents lower than the stoichiometry of Ti3SiC2 cathodes was measured in both plasma and films. Also the substrate geometry is critical for the film composition in plasma based film deposition, as evidenced by the formation of artificial layering from rotating substrate fixtures common in high capacity arc deposition systems. The layers are characterized by modulations in composition and crystallinity, primarily attributed to preferential resputtering in high ion incidence angle segments repeated through rotation.
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| 5. |
- Hellqvist, Eva, 1978-
(författare)
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Antigen interaction with B cells in two proliferative disorders : CLL and MGUS
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the work presented in this thesis was to elucidate B cell interaction with antigen in the two B cell proliferative disorders chronic lymphocytic leukemia (CLL) and monoclonal gammopathy of undetermined significance (MGUS). In the first part we investigated the antigen specificity of CLL cells and characterized Epstein-Barr virus (EBV)-transformed CLL cell lines with regard to phenotype and genotype. The second part consists of studies on the antigen presenting capacity of myelin protein zero (P0) specific MGUS B cells and their relation to T cells and development of polyneuropathy.The aim of the work presented in this thesis was to elucidate B cell interaction with antigen in the two B cell proliferative disorders chronic lymphocytic leukemia (CLL) and monoclonal gammopathy of undetermined significance (MGUS). In the first part we investigated the antigen specificity of CLL cells and characterized Epstein-Barr virus (EBV)-transformed CLL cell lines with regard to phenotype and genotype. The second part consists of studies on the antigen presenting capacity of myelin protein zero (P0) specific MGUS B cells and their relation to T cells and development of polyneuropathy.CLL cells are considered antigen experienced and different patient-derived CLL cells expressing B cell receptors (BCR) with highly homologous antigen binding sites are believed to have been selected by a common antigen at some point during the leukemogenesis. In paper I we investigated the antigen specificity of CLL-cell derived antibodies (Abs) with various IGHV gene usage and stereotyped BCR subset belonging. Identified CLL antigens included vimentin, filamin B, cofilin-1, proline rich acidic protein-1, cardiolipin, oxidized low density lipoprotein and Streptococcus pneumoniae capsular polysaccharides. Many of the CLL Abs studied displayed an oligo- or polyreactive antigen binding pattern and the identified antigens were either associated with apoptotic cells or microbial infection. This is similar to what has been described for innate natural antibodies, possibly indicating that CLL cells are derived from a natural-antibody- producing B cell population. Further characterization of CLL homology subset-2 antigen specificity showed binding to glands in human gastric mucosa corpus tissue sections for a CLL homology subset-2 Ab with HCDR3 motif-1, suggesting that this CLL subset recognize an autoantigen much like the CLL Abs tested in Paper I.Characterization of EBV-transformed CLL and normal lymphoblastoid cell lines (LCLs) in paper II showed that eight of the CLL cell lines were verified to be of authentic neoplastic origin. Indication for a biclonal CLL was found in two of the cell lines and two of the presumably normal LCLs turned out to represent the malignant CLL clone. For three cell lines no conclusive evidence for CLL origin could be found emphasizing the importance of verifying the identity of cell lines used in research.
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| 6. |
- Holmberg, Anders, 1967-
(författare)
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Essays on Model Assisted Survey Planning
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The quality of sample survey results is to a large degree dependent on decisions made by survey statisticians at the planning stage. The first paper studies two issues related to the planning stage: (i) the sensitivity of model assumptions concerning the relation between the size measure and a study variable in without replacement probability proportional-to-size sampling (πps sampling), and (ii) properties of practicable sample selection schemes for fixed size πps sampling. These two issues are also addressed in the second paper, which furthermore discusses the consequences of the presence of more than one study variable and to what extent the auxiliary information used in the design and that used in the estimators interact.The evident problem in both the first and the second paper is how to choose an overall efficient sampling design when there are several important study variables with various relationships to the available auxiliary variables. The third paper suggests a diagnostic tool to support the choice of design, and on the basis of three criteria of overall efficiency optimal designs are derived.The optimal designs presented in the third paper may not be fully satisfactory in meeting specified precision requirements for separate estimators. To achieve a design that is tailor-made to meet such requirements, optimisation must be done under restrictions. Though the underlying optimisation problem is only outlined in paper III, a solution involving non-linear programming methods is given in the fourth paper. By way of an example based on an application to a Swedish business population, the fourth paper compares a design obtained through non-linear programming algorithms with designs discussed in paper III as well as designs based on the same principal ideas as those discussed in the first two papers. The paper suggests a flexible solution regarding how to use auxiliary information exhaustively and to provide diagnostic support for the final design choice.
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| 7. |
- Hossain, Akter, 1967-
(författare)
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Studies on Redox-proteins and Cytokines in inflammation and Cancer
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The redox state in the cell plays a major role in determining vital functions and its major imbalance can lead to severe cell injury or death. Redox active proteins and cytokines involved in this process includes thioredoxin (Trx), protein disulfide isomerase (PDI), and tumor necrosis factor (TNF) superfamilies. Trx is a multipotent protein and key regulator of cellular redox balance operating in synergy with Trx reductase and NADPH (the Trx system). Trx has gene regulatory activity of several transcription factors. It also controls in a fascinating way redox-sensitive “on-off” decisions for apoptotic or hypertrophic pathways. Trx protects against H2O2 and TNFmediated cytotoxicity, a pathway in which TNF receptor-binding generates ROS. TNF is an autocrine growth factor and survival factor in vitro and in vivo for B-type of chronic lymphocytic leukemia (B-CLL) cells. The overall aim of this study was to investigate the importance of redox active proteins and cytokines in inflammation and cancer. We focused on: i) the role of Trx, TrxR, and selenium in carcinogenesis and in resistant cancer cells. ii) the importance of Trx in cancer cells and the redox regulation of TNF and its receptors TNFR1 and TNFR2. iii) the potential role of Trx as a key regulator in cellular redox balance, in the pathogenesis of cardiac dysfunction; its relationship to stress response parameters. iv) whether unmutated CLL (UCLL) responses to PKC and ROS pathways were different from mutated CLL (M-CLL) responses.Our results demonstrate pronounced selective selenium-mediated apoptosis in therapy resistant cells and suggest that redox regulation through the Trx system is an important target for cancer therapy. Trx was strikingly elevated in heart failure cases compared with controls signifying an adaptive stress response that is higher the more severe the disease. TNF autocrine release was redox modulated and the TNF receptors interacted at the cell surface membrane with the redox-active PDI, which excerted a stringent redox-control of the TNFR signaling. The proliferative response as well as increase of autocrine TNF and Trx were higher in U-CLL than in M-CLL.The overall conclusion of the four papers included in this thesis is that redox-active proteins and cytokines plays an important role in control and regulation of cancer and inflammation. Furthermore, redox regulation via thioredoxin by selenium, may offer novel treatment possibilities for resistant tumors disease.
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| 8. |
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| 9. |
- Razola, Mikael, 1984-
(författare)
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New Perspectives on Analysis and Design of High-Speed Craft with Respect to Slamming
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- High-speed craft are in high demand in the maritime industry, for example, in maintenance operations for offshore structures, for search and rescue, for patrolling operations, or as leisure craft to deliver speed and excitement. Design and operation of high-speed craft are often governed by the hydrodynamic phenomena of slamming, which occur when the craft impact the wave surface. Slamming loads affect the high-speed craft system; the crew, the structure and various sub-systems and limit the operation. To meet the ever-increasing demands on safety, economy and reduced environmental impact, there is a need to develop more efficient high-speed craft. This progression is however limited by the prevailing semi-empirical design methods for high-speed planing craft structures. These methods provide only a basic description of the involved physics, and their validity has been questioned.This thesis contributes to improving the conditions for designing efficient highspeed craft by focusing on two key topics: evaluation and development of the prevailing design methods for high-speed craft structures, and development towards structural design based on first principles modeling of the slamming process. In particular a methodological framework that enables detailed studies of the slamming phenomena using numerical simulations and experimental measurements is synthesized and evaluated. The methodological framework involves modeling of the wave environment, the craft hydromechanics and structural mechanics, and statistical characterization of the response processes. The framework forms the foundation for an extensive evaluation and development of the prevailing semi-empirical design methods for high-speed planing craft. Through the work presented in this thesis the framework is also shown to be a viable approach in the introduction of simulation-based design methods based on first principles modeling of the involved physics. Summarizing, the presented methods and results provide important steppingstones towards designing more efficient high-speed planing craft.
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| 10. |
- Rosén, Anders, 1970
(författare)
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Diving and the brain
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abstract Introduction There are reports that long-term diving is associated with cognitive impairments. This raises the question if diving itself is harmful to the brain in the absence of decompression sickness or hypoxia. Protein tau (tau), glial fibrillary acid protein (GFAp) and neurofilament light (NfL) are biomarkers whose concentrations in blood increase after traumatic brain injuries, cerebral hypoxia, and stroke, though both tau and GFAp are alleged also to change in response to cellular stress without overt damage. Inert gas bubbles are common in the blood after diving and the amount of bubbles present correlates to the risk of developing decompression sickness. The present dissertation investigates if exposure to increased ambient pressure causes tau, GFAp, or NfL concentrations in blood to increase, and if breathing oxygen after diving decreases the amount of nitrogen bubbles in blood. It includes three studies, which resulted in four papers. Methods Ten professional divers dived in the open sea over four days in the first study. Maximum dive depths ranged from 52–90 metres of seawater. Concentrations of tau, GFAp and NfL, and the amount of nitrogen bubbles in the blood was measured using Doppler ultrasound (Paper I). In the second study, 14 submariners were pressurised in a dry hyperbaric chamber to an equivalent of 30 metres of seawater and remained at that pressure for 36 hours. Thereafter, pressure was slowly decreased over 70 hours. Concentrations of tau, GFAp and NfL were measured before, during and after exposure (Paper II). In the third study, 48 professional divers were pressurised twice, 48 hours apart, to an equivalent of 42 metres of sea water for 10 minutes in a water-filled hyperbaric chamber. After one dive, oxygen was breathed for 30 minutes, with air breathed after the other. Concentrations of tau, GFAp and NfL (Paper III), and the amount of nitrogen bubbles in blood (Paper IV) after diving were analysed. Results Protein tau increased by 98.8% after four days of deep open water diving (Paper I) and by 31.5% after exposure to a pressure equivalent of 42 metres of seawater (Paper III). GFAp and NfL did not increase, and there were no associations between the amount of gas bubbles in blood and changes in protein tau (Paper I and III). Tau, GFAp or NfL concentrations did not change in response to 36 hours of exposure to a pressure equivalent of 30 metres of seawater, followed by slow decompression (Paper II). The amount of nitrogen gas bubbles in blood were significantly lower among subjects that had breathed oxygen after being pressurised in a waterfilled hyperbaric chamber to an equivalent of 42 metres of depth compared to those that breathed air (Paper IV). Conclusions Protein tau increases after diving, presumably due to neuronal stress. Unchanged NfL and GFAp concentrations suggest that neither frank neuronal injury nor astrocytic injury are involved. Oxygen breathing after diving effectively reduces the amount of nitrogen gas bubbles in blood, which decreases the risk of decompression sickness.
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