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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.
221

Biomarkers of bacteremia and sepsis in pediatric oncology patients with febrile neutropenia / Vaikų, sergančių navikinėmis ligomis, bakteriemijos bei sepsio biožymenys febrilinės neutropenijos epizodo metu

Urbonas, Vincas 15 November 2013 (has links)
This study was designed to evaluate the response of innate immunity to acute bacterial inflammation in terms of cytokines and other biomolecules concentration changes in the blood of investigated childhood oncology patients during the beginning of febrile neutropenia (FN) episode and to assess the relevance of these biomarkers for sepsis/bacteremia evaluation. This study was performed at Vilnius University Children Hospital and State Research Institute Centre for Innovative Medicine from 2009 to 2011. Serum samples were collected during 82 fever episodes in a total of 53 oncology patients. The study population consisted of pediatric oncology patients admitted to the hospital with the diagnosis of neutropenia and fever. According to microbiological and clinical findings, patients with episodes of FN were classified into 2 groups: 1) fever of unknown origin (FUO) group – patients with negative blood culture, absence of clinical signs of sepsis and clinically or microbiologically documented local infection, 2) septic/bacteremia (SB) group – patients with positive blood culture (documented Gram-positive or Gram-negative bacteremia) and/or clinically documented sepsis. We measured the levels of cytokines (IL-6, IL-8, IL-10), their receptors (sIL-2R) and other biomarkers (PCT, CRP, sHLA-G) for three consecutive days. We showed that on day 1 the most accurate biomarkers for bacteremia/sepsis discrimination were cytokines (IL-6, IL-10, IL-8), on day 2 – IL-8 and PCT. On day 1 the... [to full text] / Viena iš pagrindinių taikomos šiuolaikinės intensyvios chemoterapijos komplikacijų yra organizmo imuninės sistemos slopinimas ir su tuo susijusi neutropenija, kuri savo ruožtu sąlygoja padidėjusią riziką susirgti bakterinės kilmės infekcinėmis ligomis. Šio darbo tikslas buvo įvertinti ūmaus bakterinio uždegimo bei sepsio patogenezėje dalyvaujančių citokinų (IL-6, IL-8, IL-10), citokinų receptorių (sIL-2R), ūmios fazės baltymų bei kitų imuninio atsako komponentų (CRB, PCT, sHLA-G) tinkamumą bakterinio proceso ankstyvai diagnostikai tarp pacientų su febrline neutropenija (FN), šių biožymenų tinkamumą ir pritaikomumą kasdienėje klinikinėje praktikoje. Tiriamoji medžiaga surinkta 2009–2011 m. Vilniaus universiteto Vaikų ligoninės Onkohematologijos skyriuje. Į tyrimą buvo įtraukta 53 onkohematologinėmis ligomis sergantys vaikai su FN, kurie gydymo eigoje turėjo 82 karščiavimo epizodus. Nuo pirmos karščiavimo dienos tris dienas iš eilės buvo imami kraujo mėginiai bei nustatomos citokinų (IL-6, IL-8, IL-10), CRB, PCT, sHLA-G ir sIL-2R koncentracijos. Remiantis klinikinių bei mikrobiologinių tyrimų duomenimis, FN epizodai buvo suskirstyti į dvi grupes – neaiškios kilmės karščiavimo (NKK), į kurią buvo įtraukti pacientai be sepsio požymių bei su neigiamais mikrobiologiniais pasėliais ir bakteriemijos/sepsio (BS). BS grupę sudarė pacientai su teigiamais mikrobiologiniais pasėliais ir(ar) kliniškai diagnozuotu sepsiu. Mūsų atlikto tyrimo rezultatais bakteriemijos/sepsio vertinimui FN... [toliau žr. visą tekstą]
222

Vaikų, sergančių navikinėmis ligomis, bakteriemijos bei sepsio biožymenys febrilinės neutropenijos epizodo metu / Biomarkers of bacteremia and sepsis in pediatric oncology patients with febrile neutropenia

Urbonas, Vincas 15 November 2013 (has links)
Viena iš pagrindinių taikomos šiuolaikinės intensyvios chemoterapijos komplikacijų yra organizmo imuninės sistemos slopinimas ir su tuo susijusi neutropenija, kuri savo ruožtu sąlygoja padidėjusią riziką susirgti bakterinės kilmės infekcinėmis ligomis. Šio darbo tikslas buvo įvertinti ūmaus bakterinio uždegimo bei sepsio patogenezėje dalyvaujančių citokinų (IL-6, IL-8, IL-10), citokinų receptorių (sIL-2R), ūmios fazės baltymų bei kitų imuninio atsako komponentų (CRB, PCT, sHLA-G) tinkamumą bakterinio proceso ankstyvai diagnostikai tarp pacientų su febrline neutropenija (FN), šių biožymenų tinkamumą ir pritaikomumą kasdienėje klinikinėje praktikoje. Tiriamoji medžiaga surinkta 2009–2011 m. Vilniaus universiteto Vaikų ligoninės Onkohematologijos skyriuje. Į tyrimą buvo įtraukta 53 onkohematologinėmis ligomis sergantys vaikai su FN, kurie gydymo eigoje turėjo 82 karščiavimo epizodus. Nuo pirmos karščiavimo dienos tris dienas iš eilės buvo imami kraujo mėginiai bei nustatomos citokinų (IL-6, IL-8, IL-10), CRB, PCT, sHLA-G ir sIL-2R koncentracijos. Remiantis klinikinių bei mikrobiologinių tyrimų duomenimis, FN epizodai buvo suskirstyti į dvi grupes – neaiškios kilmės karščiavimo (NKK), į kurią buvo įtraukti pacientai be sepsio požymių bei su neigiamais mikrobiologiniais pasėliais ir bakteriemijos/sepsio (BS). BS grupę sudarė pacientai su teigiamais mikrobiologiniais pasėliais ir(ar) kliniškai diagnozuotu sepsiu. Mūsų atlikto tyrimo rezultatais bakteriemijos/sepsio vertinimui FN... [toliau žr. visą tekstą] / This study was designed to evaluate the response of innate immunity to acute bacterial inflammation in terms of cytokines and other biomolecules concentration changes in the blood of investigated childhood oncology patients during the beginning of febrile neutropenia (FN) episode and to assess the relevance of these biomarkers for sepsis/bacteremia evaluation. This study was performed at Vilnius University Children Hospital and State Research Institute Centre for Innovative Medicine from 2009 to 2011. Serum samples were collected during 82 fever episodes in a total of 53 oncology patients. The study population consisted of pediatric oncology patients admitted to the hospital with the diagnosis of neutropenia and fever. According to microbiological and clinical findings, patients with episodes of FN were classified into 2 groups: 1) fever of unknown origin (FUO) group – patients with negative blood culture, absence of clinical signs of sepsis and clinically or microbiologically documented local infection, 2) septic/bacteremia (SB) group – patients with positive blood culture (documented Gram-positive or Gram-negative bacteremia) and/or clinically documented sepsis. We measured the levels of cytokines (IL-6, IL-8, IL-10), their receptors (sIL-2R) and other biomarkers (PCT, CRP, sHLA-G) for three consecutive days. We showed that on day 1 the most accurate biomarkers for bacteremia/sepsis discrimination were cytokines (IL-6, IL-10, IL-8), on day 2 – IL-8 and PCT. On day 1 the... [to full text]
223

A Comparative Analysis of the Neurochemical Properties of Olfactory Ensheathing Cells and their Biocompatibility in Various Biomatrices

Rawji, Khalil S 31 July 2012 (has links)
Olfactory ensheathing cells (OECs) are the chief glial population of the mammalian olfactory nervous system and are thought to be responsible for the successful directional growth of new olfactory axons throughout the life of adult mammals. Due to this unique property, OECs have been targeted as a potential cellular transplantation therapy for spinal cord injury. In order to effectively isolate OECs for intraspinal transplantation, more knowledge must be gained on their phenotypic properties. We investigated the neurochemical features of OECs in a variety of mammalian species (including hamsters, rabbits, monkeys, mice, and pigs) using three biomarkers: glial fibrillary acidic protein (GFAP), S100β, and α-smooth muscle actin (αSMA). In addition, we tested the ability of a few biomatrices to sustain and promote OEC growth and survival in vitro. The rationale for using biomatrices is to provide a supportive environment for glial and axonal growth in the spinal lesion. Here, we found that mucosal and bulbar OECs from all five of the aforementioned mammalian species express S100β. Expression of GFAP, however, was not consistent across the five species. Both mucosal and bulbar OECs of monkeys express αSMA; only bulbar OECs of hamsters and only mucosal OECs of rabbits express αSMA as well. Though αSMA immunostaining was not detected in the OECs of adult mice, in adult mutant mice lacking αSMA expression, OECs displayed perturbed ultrastructural morphology. None of the biomatrices used (methacrylated glycol chitosan, arginine-glycine-aspartic acid – grafted methacrylated glycol chitosan, and agarose) were able to promote OEC proliferation. Isolated strips of rodent olfactory lamina propria (the deep connective tissue layer in the olfactory mucosa containing primary sensory axons and OECs) showed sustained growth when cultured for 10 days. In sum, these findings highlight the following points: the efficacy of S100β and αSMA as biomarkers for mammalian OECs in vivo; the potential for isolated strips of lamina propria to provide a natural, supportive environment for OECs during intraspinal transplantation; the failure of methacrylated glycol chitosan and its derivatives, as well as agarose, to promote OEC proliferation. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2012-07-27 15:29:47.642
224

Rapamycin-induced Allograft Tolerance: Elucidating Mechanisms and Biomarker Discovery

Urbanellis, Peter 12 January 2011 (has links)
The long-term success of transplantation is limited by the need for immunosuppression; thus, tolerance induction is an important therapeutic goal. A 16-day treatment with rapamycin in mice led to indefinite graft survival of fully mismatched cardiac allografts, whereas untreated hearts were rejected after 8-10 days. Specific tolerance was confirmed through subsequent skin grafts and in vitro lymphocyte assays that showed recipient mice remained immunocompetent towards 3rd party antigens but were impaired in responding to donor antigens. Mechanisms that account for this tolerant state were then investigated. Splenic CD8+CD44+ memory T-cells were reduced in tolerant mice but had increased frequencies of the CD62LLO population. CD4+CD25+Foxp3+ regulatory T-cells were increased in tolerant mice. Through multiplex PCR, 4 regulatory T-cell related genes were found up-regulated and 2 proinflammatory genes were down-regulated in accepted hearts. This expression pattern may serve as a putative biomarker of tolerance in patients undergoing transplantation.
225

Rapamycin-induced Allograft Tolerance: Elucidating Mechanisms and Biomarker Discovery

Urbanellis, Peter 12 January 2011 (has links)
The long-term success of transplantation is limited by the need for immunosuppression; thus, tolerance induction is an important therapeutic goal. A 16-day treatment with rapamycin in mice led to indefinite graft survival of fully mismatched cardiac allografts, whereas untreated hearts were rejected after 8-10 days. Specific tolerance was confirmed through subsequent skin grafts and in vitro lymphocyte assays that showed recipient mice remained immunocompetent towards 3rd party antigens but were impaired in responding to donor antigens. Mechanisms that account for this tolerant state were then investigated. Splenic CD8+CD44+ memory T-cells were reduced in tolerant mice but had increased frequencies of the CD62LLO population. CD4+CD25+Foxp3+ regulatory T-cells were increased in tolerant mice. Through multiplex PCR, 4 regulatory T-cell related genes were found up-regulated and 2 proinflammatory genes were down-regulated in accepted hearts. This expression pattern may serve as a putative biomarker of tolerance in patients undergoing transplantation.
226

Identification of potential plasma biomarkers of inflammation in farmers with musculoskeletal disorders : A proteomic study

Carlsson, Anders January 2012 (has links)
In this thesis we look for potential chronic inflammation biomarkers because studies have shown that farmers with musculoskeletal disorders might be affected by the environment to develop musculoskeletal disorders. Animal farmers are highly exposed to dust, aerosols, molds and other toxins in the air and environment leading to musculoskeletal disorders, respiratory disorders, airway symptoms and febrile reactions. There is reason to believe that the farmers have a constant or chronic inflammation that develops into musculoskeletal disorders. By using a proteomic approach with Two-dimensional Gel Electrophoresis and silver staining our goal was to find biomarkers by quantifying protein spots that differ significantly from farmers with musculoskeletal disorders compared to rural controls. In our study we found 8 significant proteins, two from Alpha-2-HS-glycoprotein, one from Apolipoprotein A1, three from Haptoglobin, one from Hemopexin and 1 from Antithrombin. All 5 proteins are involved in inflammation response in some way and some proteins are linked to chronic inflammation. Out of the 5 proteins Alpha-2-HS-glycoprotein, Apolipoprotein A1 and Hemopexin seem like the most likely proteins to investigate further as potential inflammation biomarkers.
227

Lipid biomarkers and other geochemical indicators in paleoenvironmental studies of two Arctic systems : a Russian permafrost peatland and marine sediments from the Lomonosov Ridge

Andersson, Rina Argelia January 2012 (has links)
The reconstruction of past environmental conditions is a fascinating research area that attracts the interest of many individuals in various geological disciplines. Paleoenvironmental reconstruction studies can shed light on the understanding of past climates and are a key to the prediction of future climate changes and their consequences. These studies take on special significance when focused on areas sensitive to climate change. The Arctic region, which is experiencing dramatic changes today in its peatlands and in its ocean, is prime example. The entire region plays a major role in global climate changes and has recently received considerable interest because of the potential feedbacks to climate change and its importance in the global carbon cycle. For a better understanding of the role of Arctic peatlands and the Arctic Ocean to global climate changes, more records of past conditions and changes in the region are needed. This work applies different geochemical proxies, with special emphasis on lipid biomarkers, to the study of a permafrost peat deposit collected from the Eastern European Russian Arctic and a marine core retrieved from the Lomonosov Ridge in the central Arctic Ocean. The results reported of this study show that molecular stratigraphy obtained from the analysis of lipid biomarkers in both peat and marine profiles, combined with other environmental proxies, can contribute significantly to the study of Arctic ecosystems of the past. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.</p>
228

Assessment of platinum mine tailings storage facilities : an ecotoxicological perspective / Mandy T. Jubileus

Jubileus, Mandy Theresa January 2008 (has links)
South Africa is one of the most important mining countries in the world, hosting the world's largest reserves of platinum group metals (PGMs). Even though mining is clearly an important activity in South Africa, contributing approximately US$ 7.4 billion annually to the countries' gross domestic product (GDP), the costs to the environment are not insignificant. One of the most severe environmental aspects associated with mining is the storage of mineral waste on tailings storage facilities due to their impacts on air quality, ground water quality, aesthetics and land use. It is also unknown whether the environmental effects of tailings storage facilities increase or decrease over time. The aim of this study was to determine the ecotoxicity of platinum tailings storage facilities of different ages by means of soil physical and chemical analysis, earthworm ecotoxicological studies, dehydrogenase activity and soil mesofauna studies. Samples were obtained from three platinum tailings storage facilities of different ages of which two were already rehabilitated while the third was still operational at the time this study was performed. The latter was used as a negative control for the purpose of the study. Soil samples were physically and chemically analysed. Earthworm ecotoxicological studies were conducted to determine changes in biomass, reproduction, mortality, neutral red retention times and tissue metal concentrations. Dehydrogenase activity was determined before the introduction of earthworms and manure, after introductions of manure and after introductions of earthworms and manure. Soil mesofauna were extracted and identified in order to determine species richness, diversity, abundance and functional grouping. Soil chemical analysis indicated that concentrations of certain heavy metals, especially chrome (Cr), present in platinum tailings materials could have a potential effect on microorganisms, microbial processes and earthworms. Earthworm ecotoxicological results indicated that earthworms that bioaccumulated higher levels of heavy metals showed poor hatchability of cocoons. Dehydrogenase activity indicated that earthworms play a significant role in increasing the number and biomass of soil microbes because significant increases in dehydrogenase activity were noticed after the addition of earthworms to platinum tailings materials. Results from the earthworm ecotoxicological studies, dehydrogenase activity, and soil mesofauna composition indicated that environmental impacts of tailings storage facilities did not increase with age, but is more likely to be an indication of the rehabilitation measures administered to the different tailings storage facilities. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2009.
229

Small Intestinal Neuroendocrine Tumours : Genetic and Epigenetic Studies and Novel Serum Biomarkers

Edfeldt, Katarina January 2014 (has links)
Small intestinal neuroendocrine tumours (SI-NETs) are rare, hormone producing and proliferate slowly. Patients usually display metastases at time of diagnosis, the tumours are difficult to cure, and the disease course is unpredictable. The gene expression pattern was investigated in paper I, with emphasis on aggressive disease and tumour progression. Expression microarrays were performed on 42 tumours. Unsupervised hierarchal clustering revealed three clusters that were correlated to clinical features, and expression changes from primary tumour to metastasis. Eight novel genes, ACTG2, GREM2, REG3A, TUSC2, RUNX1, TGFBR2, TPH1 and CDH6 may be of importance for tumour progression. In paper II, expression of ACTG2 was detected in a fraction of SI-NETs, but not in normal enterochromaffin cells. Inhibition of histone methyltransferase and transfection of miR-145 induced expression and no effect was seen after DNA methylation or selective EZH2 inhibition in vitro. miR-145 expression was reduced in metastases compared to primary tumours. Overexpression of ACTG2 inhibited cell growth, and inducing ACTG2 may have therapeutic effects. TCEB3C (Elongin A3) is located on chromosome 18 and is imprinted in some tissues. In paper III a reduced protein expression was detected. The gene was epigenetically repressed by both DNA and histone methylation in a tumour tissue specific context. The expression was also induced in primary cell cultures after DNA demethylation and pyrosequencing revealed promoter region hypermethylation. Overexpression of TCEB3C inhibited cell growth by 50%, suggesting TCEB3C to be a tumour suppressor gene. In paper IV, 69 biomarkers were analysed in blood serum using multiplex proximity ligation assay. Nineteen markers displayed different levels between patients and controls. In an extended cohort, ELISA analysis showed elevated serum levels of Mindin, DcR3 and TFF3 in patients and protein expression in tumour cells. High levels of DcR3 and TFF3 were associated with poor survival, and DcR3 may be a marker for liver metastases. Mindin, DcR3, and TFF3 are potential novel diagnostic biomarkers for SI-NETs.
230

Assessment of platinum mine tailings storage facilities : an ecotoxicological perspective / Mandy T. Jubileus

Jubileus, Mandy Theresa January 2008 (has links)
South Africa is one of the most important mining countries in the world, hosting the world's largest reserves of platinum group metals (PGMs). Even though mining is clearly an important activity in South Africa, contributing approximately US$ 7.4 billion annually to the countries' gross domestic product (GDP), the costs to the environment are not insignificant. One of the most severe environmental aspects associated with mining is the storage of mineral waste on tailings storage facilities due to their impacts on air quality, ground water quality, aesthetics and land use. It is also unknown whether the environmental effects of tailings storage facilities increase or decrease over time. The aim of this study was to determine the ecotoxicity of platinum tailings storage facilities of different ages by means of soil physical and chemical analysis, earthworm ecotoxicological studies, dehydrogenase activity and soil mesofauna studies. Samples were obtained from three platinum tailings storage facilities of different ages of which two were already rehabilitated while the third was still operational at the time this study was performed. The latter was used as a negative control for the purpose of the study. Soil samples were physically and chemically analysed. Earthworm ecotoxicological studies were conducted to determine changes in biomass, reproduction, mortality, neutral red retention times and tissue metal concentrations. Dehydrogenase activity was determined before the introduction of earthworms and manure, after introductions of manure and after introductions of earthworms and manure. Soil mesofauna were extracted and identified in order to determine species richness, diversity, abundance and functional grouping. Soil chemical analysis indicated that concentrations of certain heavy metals, especially chrome (Cr), present in platinum tailings materials could have a potential effect on microorganisms, microbial processes and earthworms. Earthworm ecotoxicological results indicated that earthworms that bioaccumulated higher levels of heavy metals showed poor hatchability of cocoons. Dehydrogenase activity indicated that earthworms play a significant role in increasing the number and biomass of soil microbes because significant increases in dehydrogenase activity were noticed after the addition of earthworms to platinum tailings materials. Results from the earthworm ecotoxicological studies, dehydrogenase activity, and soil mesofauna composition indicated that environmental impacts of tailings storage facilities did not increase with age, but is more likely to be an indication of the rehabilitation measures administered to the different tailings storage facilities. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2009.

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