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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
371

Interplay between tick-borne encephalitis virus and the host innate immunity

Kurhade, Chaitanya January 2017 (has links)
Flaviviruses are important emerging and re-emerging arthropod-borne pathogens that cause significant morbidity and mortality in humans. It consists of globally distributed human pathogens such as tick-borne encephalitis virus (TBEV), West Nile virus (WNV), Japanese encephalitis virus (JEV), yellow fever virus (YFV), dengue virus (DENV), and Zika virus (ZIKV). Depending on type, flaviviruses can cause a variety of symptoms ranging from haemorrhage to neurological disorders. Virus infection is detected by host pattern recognition receptors (PRRs), and through downstream signalling it leads to the production of interferons (IFNs). These IFNs then act in an autocrine or paracrine manner on the cells to induce various IFN-stimulated genes (ISGs), which have antiviral roles. However, the amount of IFN produced depends on the nature of the PRRs used by host cells to detect a particular virus. Although there are many PRRs present in the host cells, their relative contribution in different cell types and against a specific virus may vary. In the first study, we determined the importance of IPS-1 signalling in immunity and pathogenicity of tick-borne flaviviruses. This is an adaptor protein for cytoplasmic RIG-I-like receptors. Using IPS-1-deficient mice, we showed its importance against TBEV and Langat virus (LGTV) infection (the LGTV model virus belongs to the TBEV serogroup). Absence of IPS-1 leads to uncontrolled virus replication in the central nervous system (CNS), but it has only a minor role in shaping the humoral immune response at the periphery. LGTV-infected IPS-1-deficient mice showed apoptosis, activation of microglia and astrocytes, an elevated proinflammatory response, and recruitment of immune cells to the CNS. Interestingly, we also found that IFN-b upregulation after viral infection was dependent on IPS-1 in the olfactory bulb of the brain.  Thus, our results suggest that local immune microenvironment of distinct brain regions is critical for determination of virus permissiveness. Interferons can upregulate several ISGs. Viperin is one such ISG that has a broad-spectrum antiviral action against many viruses. However, the importance of cell type and the significance of viperin in controlling many flavivirus infections in vivo is not known. Using viperin-deficient mice, we found that viperin was necessary for restriction of LGTV replication in the olfactory bulb and cerebrum, but not in the cerebellum. This finding was also confirmed with primary neurons derived from these brain regions. Furthermore, we could also show the particular importance of viperin in cortical neurons against TBEV, WNV, and ZIKV infection. The results suggested that a single ISG can shape the susceptibility and immune response to a flavivirus in different regions of the brain. Although viperin is such an important ISG against flaviviruses, the exact molecular mechanism of action is not known. To understand the mechanism, we performed co-immunoprecipitation screening to identify TBEV proteins that could interact with viperin. While viperin interacted with the prM, E, NS2A, NS2B, and NS3 proteins of TBEV, its interaction with NS3 led to its degradation through the proteosomal pathway. Furthermore, viperin could reduce the stability of other viperin-binding TBEV proteins in an NS3-dependent manner. We screened for viperin activity regarding interaction with NS3 proteins of other flaviviruses. Viperin interacted with NS3 of JEV, ZIKV, and YFV, but selectively degraded NS3 proteins of TBEV and ZIKV, and this activity correlated with its antiviral activity against these viruses. The last study was based on in vivo characterization of the newly isolated MucAr HB 171/11 strain of TBEV which caused unusual gastrointestinal and constitutional symptoms. This strain was compared with another strain, Torö-2003, of the same European subtype of TBEV but isolated from the different focus. Here we found unique differences in their neuroinvasiveness and neurovirulence, and in the immune response to these two strains. In summary, my work shed some light on the interplay between tick-borne flavivirus and the innate immune system. I have shown two examples of CNS region-specific differences in innate immune response regarding both in IFN induction pathways and antiviral effectors. Furthermore, we have investigated the in vivo pathogenesis of a strain of TBEV that caused unusual gastrointestinal and constitutional symptoms. / Flavivirus finns spridda över hela världen och orsakar miljontals infektioner varje år. Några av de medicinsk mest viktiga flavivirusen är fästingburen encefalit virus (TBEV), West Nile virus (WNV), Japansk encefalit virus (JEV), gula febern (YFV) och Zika virus (ZIKV). Dessa virus kan orsaka olika komplikationer till exempel blödarfeber och hjärninflammation. Vid en infektion så upptäcker värdcellen virusinfektionen med hjälp av speciella receptorer, så kallade PRRs. Dessa finns i alla celler och känner igen viruskomponenter som normalt inte finns i en oinfekterad cell. När PRRs detekterar en virusinfektion svarar cellen med att tillverka ett signal protein interferon (IFN). IFN skickas ut ur cellen och hämmar virusinfektioner genom att sätta igång ett försvarsprogram i andra celler bestående av hundratals försvarsproteiner som kan motverka virusinfektionen. Vilka PRRs som behövs för att detektera ett virus är olika vid olika virusinfektioner. I första studien fann vi att IPS-1 är av yttersta vikt för skydda mot fästingburna flavivirus. IPS-1 är ett så kallat adapter protein som behövs för att två PRRs, RIG-I och MDA-5, ska kunna förmedla signaler som leder till IFN tillverkning. Med hjälp av möss som saknar IPS-1 fann vi att IPS-1 behövs för att tillverka IFN protein och skydda mot fästingburna flavivirus. IPS-1 var särskilt viktigt för interferon produktion inom luktloben i hjärnan. Därför kunde vi dra slutsatsen att immunresponsen regleras olika inom olika delar av hjärnan. Ett försvarsprotein som visat sig vara särskilt viktig vid virusinfektion är viperin. Viperin har visat sig kunna hämma en rad olika virus men den specifika rollen av viperin in vivo vid flavivirus infektion var inte fullt känd. Vi fann att viperin behövs för att hämma LGTV i lukloben och storhjärnan men inte i lillhjärnan. Vi kunde bekräfta detta med hjälp av primära nervceller isolerade från dessa hjärnregioner. Vi fann även att viperin var av yttersta vikt för att kontrollera TBEV, WNV och ZIKV infektion i nervceller från hjärnbarken (del av storhjärnan). Därför kunde vi dra slutsatsen att ett enskilt försvarsprotein kan avgöra mottagligheten mot flavivirus inom olika hjärnregioner. Trots att viperin är så viktig för att skydda mot flavivirus så vet vi inte hur viperin åstadkommer detta. Därför ville vi undersöka hur viperin kan förmedla sin antivirala effekt. Vi fann att viperin kan binda till flera TBEV proteiner, men att viperin specifikt kan bryta ner ett virusprotein som heter NS3. NS3 är väldigt viktigt för att flavivirus ska kunna etablera en infektion och kunna föröka sig. Eftersom vi visste att viperin kan hämma andra flavivirus ville vi veta om viperin även förstör NS3 från JEV, ZIKV och YFV. Vi upptäckte att viperin kunde binda till NS3 hos alla dessa flavivirus men att viperin specifikt förstörde TBEV och ZIKV NS3, intressant nog så kunde viperin endast hämma dessa virus infektioner men inte JEV och YFV. I den sista studien ville vi karaktärisera en ny TBEV stam som bara orsakar magoch tarmbesvär men inga neurologiska symptom. TBEV har aldrig tidigare visat sig kunna orsaka detta och därför ville vi undersöka saken vidare. Vi fann att denna TBEV stam skiljde sig mot en närbesläktad stam genom att orsaka en starkare immunrespons men mildare sjukdomsförlopp. Sammanfattningsvis har jag undersökt samspelet mellan fästingburna flavivirus och det medfödda immunförsvaret. Jag har även visat att immunresponsen regleras olika inom olika hjärnregioner, både beträffande IFN inducering och antivirala proteiner. Vidare har jag hittat mekanismen för hur viperin proteinet hämmar TBEV och ZIKV, vilket var genom att förstöra NS3. Dessutom har jag karaktäriserat sjukdomsförloppet hos möss efter infektion med en ovanlig TBEV stam som orsakar mag och tarm besvär.
372

Kartläggning i förskolan : Att hjälpa eller att stjälpa / Educational mapping in preschool : To benefit children or to cause difficulties for them

Ljungström, Hampus, Lövgren, Anna January 2018 (has links)
Educational mapping in preschool To benefit children or to cause difficulties for them   Syftet med denna studie är att bidra med kunskap om varför en kartläggning i förskolan blir aktuell, utifrån förskollärares perspektiv. Följande frågeställningar låg till grund för undersökningen: Vad ska kartläggningen leda till? Och hur går en kartläggning till? Metoden som använts för att svara på forskningsfrågorna är semistrukturerade intervjuer som genomförts med fyra förskollärare som arbetar på olika förskolor i samma kommun. Resultatet i denna studie pekar på att förskollärare ser den pedagogiska kartläggningen som ett hjälpmedel i arbetet med att erbjuda alla barn ett likvärdigt lärande i förskolan. Undersökningens resultat pekar även på att förskollärare inte anser att en diagnos skall vara nödvändig för att barn ska få det stöd de behöver i förskolan, det framkommer dock att det finns svårigheter i att erbjuda alla barn det stöd de behöver utan att det finns en diagnos. Svårigheter i att anpassa miljön efter alla barns behov uppges bottna i ekonomiska frågor samt hur lokalerna är utformade.
373

DNA profiles generated from minute amounts of single cells

Wenäll, Lovisa January 2011 (has links)
The genetic code in our cells is built up by deoxyribonucleic acid (DNA) with a sequence that is individual and unique to each person. A cell’s origin can be decided by comparing an established DNA profile with a known profile. The most publicly known application is in the forensic field and its use for identification and for establishing a connection between perpetrators and victims or crime scenes. DNA profiling is also commonly used for kinship investigations. The information embedded in the DNA is also used for diagnostic purposes in conventional medicine. Generating DNA profiles is a well-established procedure, which is used daily and for many purposes. An amount of approximately 150-1500 cells is required to be able to establish a full DNA profile using current methods. There are several situations where the amount of material is limited. To enable analysis where the testing material is limited it is of great value to develop a method that can perform these analyses on minute amounts of cells. If there were a method for generating DNA profiles from single cells then mixed samples from crime scenes would be separable. In tumour biology it is also of interest to obtain information from single cells. The aim with the thesis was to establish the smallest amount of cells needed for a full DNA profile. The thesis started with analyses on extracted DNA. During several experiments dilution series were made to investigate the possibilities to establish profiles from minute amounts of extracted DNA. The main methods used during this thesis were polymerase chain reaction (PCR) and capillary gel electrophoresis (CGE). These methods are well-established tools both in biomedical science and at The Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine. Different factors were optimized and the acquired knowledge resulted in application of DNA on FTA® Micro Cards. The cards are used in the daily routines and are easy to use. Several experiments were then performed on peripheral lymphocytes based on the knowledge acquired during the process. Applying a low amount of lymphocytes on FTA cards proved to be very successful and the method generates DNA profiles at a single cell level. The method is applicable for approximately 5-10 cells.
374

Quantification of Tripeptidyl-peptidase II : Optimisation and evaluation of 3 assays

Gyllenfjärd, Sabina January 2010 (has links)
Abstract   Tripeptidyl-peptidase II (TPPII), is present in most eukaryotic cells. It cuts tripeptides from the N-terminus of peptides and is especially important for degrading peptides longer than 15 amino acids. TPPII also tailors long peptides into suitable substrates for the enzymes which transport and produce the peptides that MHC I present. Increased levels of TPPII have also been found in certain cancer cells, thus it is of interest to determine if TPPII could be used as a tumour marker. The aim of this study was to optimise and evaluate 3 different methods for quantifying TPPII. Western blot, enzyme-linked immunosorbent assay (ELISA) and fluorophore-linked immunosorbent assay (FLISA) protocols were optimised regarding incubation times and antibody dilutions. Sensitivity and linearity were the most important parameters when evaluating the results. The coefficient of determination of western blot was R2=0.98-1 within the range of 1.29-250ng TPPII/well and ELISA had a coefficient of determination of R2=0.96 within the range of 0.03-250ng TPPII/well. Presently western blot is the only one of these methods to yield reliable results with impure samples, but ELISA is superior regarding sensitivity and throughput. Thus further optimisation of ELISA is interesting to pursue.
375

QUALITY OF TACSI PLATELETS AND THEIR EFFECT ON THROMBOCYTOPENIA PATIENTS

Lundin, Ann-Sofie January 2010 (has links)
Conclusion:Medical treatment may have a role in platelet count after transfusion. Since the TACSI platelets passed the quality requirements, and the vast majority of patients platelet count increased after TACSI platelet transfusion, the TACSI platelets will replace the old method to produce platelets at the Uppsala University hospital.     Methods: A new approach that pools 8 buffy coats (TACSI platelets) that were separated into 2 units instead of 4-6 buffy coats pooled to 1 unit was investigated in this study. After the platelets were extracted from the buffy coats their quality was controlled and subsequently the platelet product was evaluated in 96 patients.   Results: The results showed that 80 % of the platelet units passed the European quality requirements. Further, the platelet count was increased in most patients that received TACSI platelets. Conclusion: Medical treatment may have a role in platelet count after transfusion. Since the TACSI platelets passed the quality requirements, and the vast majority of patients platelet count increased after TACSI platelet transfusion, the TACSI platelets will replace the old method to produce platelets at the Uppsala University hospital.
376

Proliferation Signal Inhibitor associated proteinuria in a renal transplant recipient: Dysfunction of proximal tubular epithelial cells is a result of decreased cubilinand/or megalin expression? : Proliferation Signal Inhibitor associated Proteinuria

Komuraiah, Myakala January 2010 (has links)
Background The proliferation signal inhibitors (PSIs) sirolimus (SRL) and everolimus (ERL) are the potent immunosuppressive drugs using in organ transplantation and has been used successfully in renal transplant recipients (RTX) as well. PSIs are the key factors to overcome the allograft rejections after successful organ transplantation since the immune system starts to react against the graft. SRL and ERL prevents the action of immune system b inhibits the proliferation of T- and B-cells by inhibiting the intracellular signaling of interleukin-2. The presence of excess amount of serum proteins including albumin in the urine is considered as proteinuria, which reflects the loss of kidney function. The occurrence of proteinuria can be the result of abnormal glomerular filtration and/or impaired tubular endocytic function of renal proximal tubular epithelial cells (PTECs). Megalin and cubulin are two scavenger receptors present on epical surface of PTECs and involved in reabsorption of proteins after glomerular ultrafiltration process in the kidney. Proteinuria appears too high in renal transplanted patients during ongoing   treatment with PSIs. Aim Our study aimed to investigate and correlate the expression level of megalin and cubilin and albumin uptake in PTEC of renal transplanted patients before and after conversion to PSI. Methods To retrieve the maximal expression of our interest molecules in renal PTECs, we optimized antigen retrieval (AR) method and primary antibody dilution for each molecule separately. An optimization experiment was performed on 3 different normal patients renal biopsies were used. Later, human renal biopsy specimens originated from 4 different renal transplanted patients were used in this study. From all the 4 patients biopsy specimens were taken before and ongoing administration of PSIs (SRL, ERL). The expression of megalin, cubilin and albumin uptake in PTEC of renal transplant patients was determined by immunohistochemical staining. Results Based on the optimization experiments, we selected the AR method and primary antibody dilution for the expression of megalin, cubilin and albumin uptake. In 4 renal transplanted patients following administration of PSIs results in patients 1, 2, 3 expression of megalin, cubilin and albumin uptake during ongoing PSI treatment was not comparable or even more intense than before PSIs introduction. The expression of megalin, cubilin and albumin uptake was reduced in patient 4 during ongoing PSI treatment. Conclusion Our findings suggest that the renal transplant patient 4 developed proteinuria during PSI medication. The expression of megalin, cubilin and albumin uptake was markedly decreased during ongoing PSI treatment in patient 4. We concluded that there is a direct link between PSI medication and tubular dysfunction, which might cause proteinuria
377

Detection And Quantification Of Equine Type I Interferons

Wahlund, Casper January 2011 (has links)
Type I interferons (IFNs), perhaps the most important of cytokines in fighting viral infections, have been target for detailed research only the past few decades and much is yet to be investigated. Hidden in the mysteries of IFNs might be powerful anti-viral and anti-tumor therapies, alongside greatly increased understanding of vertebrate immunology. This project aims at investigating IFN expression of in vitro stimulated equine cell lines and studies of IFN expression in horses, both healthy and a number of horses diagnosed with inflammatory bowel disease (IBD). Amongst equine diseases, IBD is of increasing concern and scientific progressions within the project are, in several aspects, also applicable for human medicine.
378

In Vitro Study of Recruitment Ability of Macrophages and Trophoblasts in Early Human Pregnancy

Wendel, Caroline January 2010 (has links)
The tolerance towards the semi-allogenic foetus is obtained through both systemic and local changes in the maternal immune response. Locally, in the decidua, the cell composition differs from that found in the blood; natural killer (NK) cells and macrophages being the major cell types. Decidual macrophages (dMØ), which are alternatively activated, and trophoblasts, placental cells of foetal origin, are believed to participate in the foetal tolerance at the foetal-maternal interface. To test the recruitment ability of macrophages and trophoblasts, and to test if these cells are responsible for the special cell composition in the decidua, a migration assay was established. In this migration assay peripheral blood mononuclear cells (PBMC) were allowed to migrate through Matrigel-coated transwell inserts into lower wells containing a recruiting stimulus. After testing several conditions, a protocol was established for further use. The results showed that in vitro alternatively activated macrophages, which display many of the surface markers as dMØ, hold a recruiting ability and recruit monocytes. Further there was an indication that trophoblasts also hold a recruiting ability. Neither cell types were shown to recruit NK cells. In conclusion, this study presents a suitable protocol for assessing chemotactic factors and different cell type’s ability to recruit cells from blood. Although the experiments need to be repeated and extended and the recruitment ability of dMØ needs to be evaluated in detail before a final conclusion can be drawn, the preliminary data indicated that macrophages and trophoblasts can recruit monocytes.
379

Film i undervisningen – i egen rätt eller bara komplement? : En kvalitativ studie av tre lärares syn på spelfilm iundervisningen / Film in education – on its own or just a complement? : A qualitative study of three Swedish teachers´ views of using film in teaching

Källén, Ida January 2009 (has links)
The aim of this paper is to examine which attitudes and experiences teachers have around the wide text concept, which is found in the course plan for the Swedish subject, and to find out which function films have in their teaching. The starting point of the paper’s theoretical part is the Swedish subject’s course plans and current research concerning the wide text concept and film in teaching. In order to achieve the formulated aim, qualitative interviews have been performed with three Swedish teachers active in the later years of compulsory-school. The result shows that there are divided opinions of the actual meaning of the concept. However the three teachers agree that film has something to enrich the teaching of the Swedish language and they are for most part positive to using film in their teaching. There are certain differences as to how film is practically used in teaching by the three interviewed teachers, but film is used largely in three ways as also the researcher Christina Olin-Scheller has concluded: as illustration, as complement and as comparison. The three interviewed teachers also mean that the students, for most parts, are positive to using film as a teaching method and that lessons using film function satisfactory.
380

Attityder, ålder och språkundervisning : Några gymnasieelevers upplevelser av och attityder till svenska språket i Finland

Koivisto, Milla January 2009 (has links)
Syftet med min uppsats är att studera attityder till svenska språket i Finland. Jag har intervjuat sju finskspråkiga gymnasieelever i södra Finland. Syftet med intervjuerna är primärt kvalitativt. Jag har velat bilda mig en uppfattning om vilka faktorer som påverkar de intervjuades attityder och även försöka förstå varför man har de attityder man har och vari de bottnar. Jag har även velat se hur ålder vid studiestarten i svenska påverkarattityderna. Därför har jag valt att intervjua både dem som har börjat studera svenska i lågstadiet och dem som börjat sina studier i högstadiet. Resultatet visar att det finns flera faktorer som påverkar de intervjuades attityder. En faktor är kontakter med de svenskspråkiga och den vardagliga närvaron (eller frånvaron) av svenska språket. Undervisningens kvalitet och hurdan lärare man har i svenskämnet påverkar också. Även omgivningens attityder kan ha en viss påverkan. Bland mina informanter framstår den instrumentella funktionen som mest central i formandet av attityderna: informanterna läser svenska för att de tror sig ha nytta av det nu och i framtiden. Även den affektiva funktionen påverkar i vissa fall informanterna: en positiv attityd till svenska språket samt en stor vilja och motivation att lära sig det uttrycker en lust att känna tillhörighet till den andra gruppen (svenskspråkiga) utöver den egna (finskspråkiga). Flera informanter har åsikter om ålder vid studiestart i svenska och hur det kan påverka attityderna. Alla mina informanter har en positiv eller mer neutral attityd till svenska språket i sig och även de svenskspråkiga. Gällande åsikter om den obligatoriska undervisningen i svenska i Finland är åsikterna delade.

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