81 |
A combined model of human erythropoiesis and granulopoiesis under growth factor and chemotherapy treatmentSchirm, Sibylle, Engel, Christoph, Löffler, Markus, Scholz, Markus January 2014 (has links)
Background: Haematotoxicity of conventional chemotherapies often results in delays of treatment or reduction of chemotherapy dose. To ameliorate these side-effects, patients are routinely treated with blood transfusions or haematopoietic growth factors such as erythropoietin (EPO) or granulocyte colony-stimulating factor (G-CSF). For the latter ones, pharmaceutical derivatives are available, which differ in absorption kinetics, pharmacokinetic and -dynamic properties. Due to the complex interaction of cytotoxic effects of chemotherapy and the stimulating effects of different growth factor derivatives, optimal treatment is a non-trivial task. In the past, we developed mathematical models of thrombopoiesis, granulopoiesis and erythropoiesis under
chemotherapy and growth-factor applications which can be used to perform clinically relevant predictions regarding the feasibility of chemotherapy schedules and cytopenia prophylaxis with haematopoietic growth factors. However, interactions of lineages and growth-factors were ignored so far. Results: To close this gap, we constructed a hybrid model of human granulopoiesis and erythropoiesis under conventional chemotherapy, G-CSF and EPO applications. This was achieved by combining our single lineage models of human erythropoiesis and granulopoiesis with a common stem cell model. G-CSF effects on erythropoiesis were also implemented. Pharmacodynamic models are based on ordinary differential equations describing proliferation and maturation of haematopoietic cells. The system is regulated by feedback loops partly mediated by endogenous and exogenous EPO and G-CSF. Chemotherapy is modelled by depletion of cells. Unknown model parameters were determined by fitting the model predictions to time series data of blood counts and cytokine profiles. Data were extracted from literature or received from cooperating clinical study groups. Our model explains dynamics of mature blood cells and cytokines after growth-factor applications in healthy volunteers. Moreover, we modelled 15 different chemotherapeutic drugs by estimating their bone marrow toxicity. Taking into account different growth-factor schedules, this adds up to 33 different chemotherapy regimens explained by the model. Conclusions: We conclude that we established a comprehensive biomathematical model to explain the dynamics of granulopoiesis and erythropoiesis under combined chemotherapy, G-CSF, and EPO applications. We demonstrate how it can be used to make predictions regarding haematotoxicity of yet untested chemotherapy and growth-factor schedules.:Background; Methods; Results; Model predictions; Discussion; Conclusions
|
82 |
Regulation of colony stimulating factor-1 expression and ovarian cancer cell behavior in vitro by miR-128 and miR-152Woo, Ho-Hyung, Laszlo, Csaba, Greco, Stephen, Chambers, Setsuko January 2012 (has links)
BACKGROUND:Colony stimulating factor-1 (CSF-1) plays an important role in ovarian cancer biology and as a prognostic factor in ovarian cancer. Elevated levels of CSF-1 promote progression of ovarian cancer, by binding to CSF-1R (the tyrosine kinase receptor encoded by c-fms proto-oncogene).Post-transcriptional regulation of CSF-1 mRNA by its 3' untranslated region (3'UTR) has been studied previously. Several cis-acting elements in 3'UTR are involved in post-transcriptional regulation of CSF-1 mRNA. These include conserved protein-binding motifs as well as miRNA targets. miRNAs are 21-23nt single strand RNA which bind the complementary sequences in mRNAs, suppressing translation and enhancing mRNA degradation.RESULTS:In this report, we investigate the effect of miRNAs on post-transcriptional regulation of CSF-1 mRNA in human ovarian cancer. Bioinformatics analysis predicts at least 14 miRNAs targeting CSF-1 mRNA 3'UTR. By mutations in putative miRNA targets in CSF-1 mRNA 3'UTR, we identified a common target for both miR-128 and miR-152. We have also found that both miR-128 and miR-152 down-regulate CSF-1 mRNA and protein expression in ovarian cancer cells leading to decreased cell motility and adhesion in vitro, two major aspects of the metastatic potential of cancer cells.CONCLUSION:The major CSF-1 mRNA 3'UTR contains a common miRNA target which is involved in post-transcriptional regulation of CSF-1. Our results provide the evidence for a mechanism by which miR-128 and miR-152 down-regulate CSF-1, an important regulator of ovarian cancer.
|
83 |
Meningeosis neoplastica: Der Einfluss von Tumorart und Liquorzellzahl auf die Diagnostik / Neoplastic meningitis: How MRI and CSF cytology are influenced by CSF cell count and tumor typePrömmel, Peter 27 July 2016 (has links)
No description available.
|
84 |
Environmental factors affecting interferon-τ expression and secretion by in vitro produced bovine blastocystsHickman, Cristina Fontes Lindemann January 2010 (has links)
Interferon (IFN)τ is the luteotrophic signal in ruminants and is secreted by bovine blastocysts both in vivo and in vitro. IFNτ secretion is highly variable and its control is only partly understood. Most studies on the effects of environmental factors on IFNτ production have evaluated IFNτ production during the time of embryo elongation and attachment. There is less knowledge of how IFNτ production at the blastocyst stage is modulated. Therefore, the hypothesis of this thesis was that the amounts of IFNτ expressed and/or secreted by bovine blastocysts produced in vitro were modulated by environmental factors. In the first set of experiments, bovine embryos were incubated with a cytokine (granulocyte macrophage colony stimulating factor, GM-CSF). GM-CSF had been shown previously to promote embryo viability in a range of species and to modulate IFNτ secretion by ovine blastocysts and thus was classified as a beneficial environmental factor. Three experiments were conducted to test whether GM-CSF stimulated bovine blastocyst development and IFNτ secretion. Embryos were incubated with a range of different concentrations of GM-CSF (2, 5, 10 and 50 ng mL-1) and at different stages of development (1 to 3 and 1 to 9 days post-insemination). Bovine embryos were unresponsive to GM-CSF in terms of IFNτ secretion, pyruvate oxidation, rate of development, blastocyst yield, morphological quality and apoptotic index, irrespective of timing of exposure and/or concentration of GM-CSF. In the second part of the thesis, bovine blastocysts were exposed to a mild heat treatment (42°C for four h) to determine whether heat stress affected IFNτ expression by bovine blastocysts. A novel multiplex reverse-transcription polymerase chain reaction methodology was validated to detect IFNτ and heat shock protein (HSP)70 mRNA in individual bovine embryos relative to an endogenous gene (YWHAZ) and an exogenous mRNA (α-globin) and results were expressed both in absolute terms and in relation to the endogenous control. Heat treatment upregulated IFNτ mRNA expression, suggesting that detrimental environmental factors may influence IFNτ expression. Heat treatment also caused an increase in HSP70 mRNA expression but did not affect blastocyst morphology, suggesting that the level of stress caused by the heat treatment was great enough to activate the cellular stress response, but mild enough not to cause a change in morphology. In addition, the positive correlation between HSP70 and IFNτ transcript levels and the higher IFNτ expression by embryos which showed signs of degeneration and collapse compared to those which progressed in development suggested that IFNτ expression may be indicative of stress. The relationship between IFNτ expression and secretion in vitro with morphology, pyruvate metabolism, apoptotic index and cell number was inconsistent, suggesting that IFNτ production did not correlate with ‘quality’ (defined as an index of viability). Blastocyst yield, day of blastulation and change in morphology index did account for at least part of the variation in IFNτ production, suggesting that some intrinsic factors may regulate IFNτ secretion. These intrinsic factors, however, did not explain all the variation in IFNτ secretion between blastocysts. Therefore, the amount of IFNτ secreted by bovine blastocysts is modulated by both intrinsic and environmental factors. A model was proposed where different levels of stress affect survivability to different extents, and the ability to respond to mild levels of stress may be indicative of improved survivability.
|
85 |
An evaluation of performance improvement within public sector construction framework agreementsGale, Keith January 2013 (has links)
Context of this research: The construction industry has a history of client dissatisfaction in the UK. In response, framework agreements have been developed to create relationships between suppliers and clients in order to improve project performance. This research aims to assess whether use of framework agreements can result in significant improvement for performance outcomes without a significant increase in costs when compared with traditional discrete methods, and if so, develop a procurement performance model for realisation and continuous improvement in performance. Research methodology: A literal review of UK Government reports with economic and performance management theories precede a case study set within Hampshire County Council, a major public sector authority, allowing analysis of data from 164 highway maintenance projects by independent samples t-tests. Projects are divided into discrete and framework groups using critical success factors to measure performance differences. In addition to project outcomes, a review of economic performance was undertaken to advance a current ‘gap in professional knowledge’ concerning cost effectiveness of framework agreements. A performance management model is proposed representing impact of operational measures and sociological behaviour factors on suppliers’ performance, tested by qualitative views of experienced practitioners collected through a questionnaire survey and in-depth interviews. Key findings: Independent-samples t-tests proved that there were significant improvements in performance with use of framework agreements, but that no significant additional costs were incurred. Factor analysis and central tendency statistics from questionnaires and node values from interview transcripts confirmed long-term relationships, financial and non–financial incentives and stronger communication were sociological behaviour factors driving performance for framework agreements. Conclusions from the evidence and findings: As framework agreements can achieve significant performance improvements without a significant increase in costs, this study supports use of framework agreements for Hampshire County Council and professional practice. Value of this research is recognised by both central government and case study organisation alike. In respect of the latter context, case study findings have been included within a regional framework for use by South East authorities until 2016. It is recommended further studies should be conducted on civil and building projects in wider public and private sectors so that construction clients can make informed decisions based upon generalised findings.
|
86 |
Interaction entre le GM-CSF et PU.1 dans la survie des précurseurs myéloïdesSt-Denis, Marianne January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
|
87 |
Fatores críticos de sucesso na gestão de projetos colaborativos de desenvolvimento de máquinas agrícolas: um estudo de caso / Critical success factors in the administration of collaborative projects of development of agricultural machines: a case studyReame Júnior, Euclides 01 September 2008 (has links)
Os projetos de desenvolvimento realizados em colaboração são fundamentais para que as empresas de máquinas agrícolas consigam aumentar o grau de inovação em produtos, permitindo-as acompanhar os novos desafios de um mercado mais competitivo. Há na literatura vários trabalhos que identificam fatores críticos de sucesso (FCS) para projetos colaborativos, porém, não há muitos estudos sobre a verificação desses fatores no Brasil, em especial na indústria de máquinas agrícolas (IMA). Este trabalho tem como objetivo verificar se os FCS identificados na literatura poderiam ser empregados nesse contexto. Empreendeu-se uma revisão bibliográfica para identificar os fatores críticos de sucesso em projetos colaborativos de desenvolvimento de produtos e uma revisão sobre indústria de máquinas agrícolas (IMA), de forma a entender as especificidades desse setor no Brasil. Em seguida, realizou-se um levantamento em uma empresa do setor, com nível de maturidade elevado em desenvolvimento de produto, medido conforme Simões (2007), para verificar se os FCS identificados poderiam ser utilizados em levantamentos no setor e verificar se não havia outros fatores a serem considerados, específicos para o segmento e região. Utilizou-se o método do estudo de caso único, do tipo incorporado. A unidade de análise é constituída por projetos do tipo colaborativo, realizados com sucesso pela empresa. Foram analisados dois projetos de produtos inovadores, com diferentes tipos de parceiro: um com um cliente e outro com um fornecedor. Os dados foram coletados por meio de entrevistas e o instrumento de pesquisa é um roteiro. As instalações da empresa foram visitadas com o objetivo de conhecer os projetos analisados. Como resultado afirma-se que há fatores descritos na literatura que podem não ser críticos; indica-se a existência de novos FCS e reforça-se a importância dos fatores ligados à garantia de igualdade e fatores universais de sucesso. A contribuição do trabalho é uma lista de fatores críticos de sucesso que podem servir como passo inicial para levantamentos gerais de campo no setor industrial estudado. / The collaborative projects of development are one of the main tools in order to agricultural machines companies get to increase the innovation degree in products, allowing them to follow the new challenges of a more competitive market. There is in the literature several works that identify critical success factors (CSF) for collaborative projects; however, there are not many studies about the verification of those factors in Brazil, especially in the agricultural machinery industry. The aim of this work is to verify if identified CSF in the literature could be used in that context. A bibliographical revision was undertaken to identify the \"critical success factors\" in collaborative projects of development of products and a revision on agricultural machines industry in order to understand the specificities of that section in Brazil. After that it has taken place a survey in a company of that sector, with high level of maturity in development of measured product according to Simões (2007), to verify if identified CSF could be used in surveys in that sector and to verify if there were any other factors to be considered, specific for that segment and field. A case study was used and the units of analysis are collaborative projects accomplished successfully by the company. Two projects development of products were analyzed, with different kinds of partner: one with a customer and the other with a supplying company. Besides the interviews it has taken visits to the companies in order to know the analyzed projects. There are factors described that could not be critical; the results indicate the existence of new critical factors and they confirm the importance of equality and universal factors as critical for collaborative projects. The main contribution of these projects is a list of critical factors of success that one can serve as initial step for general survey in this field.
|
88 |
Importance of key success factors for local and international NGOs in humanitarian supply chainAzmat, Muhammad, Kummer, Sebastian January 2019 (has links) (PDF)
Background: Local and international non-governmental organizations play a pivotal role in a relief operation. However, as the number of disasters and their complexity is increasing, the challenges these organizations face during a relief operation are also growing exponentially. It is crucial for relief organizations to not only understand but also to prioritize the factors, which can make their supply chain work better. Therefore, this research aims at understanding the relationship between the key success factors, which can dramatically enhance the efficiency and effectiveness of the relief operation. Moreover, this study also highlights how LNGOs and INGOs differentiate between these KSFs and how they rank them.
Methods: To address the objective of this study, the Likert scale style questionnaire was developed and distributed online to all such NGOs (worldwide), which take part in the relief operation. The collected data was then tested for its empirical significance on SPSS using Spearman's Rho, Pearson Chisquare, to understand the relationship and importance of these factors. Whereas, the odds ratio was calculated to rank each KSF.
Results: The results of the study indicate that there exist strong correlation among all selected factors and all KSFs affect INGOs supply chain at least twice as much as they do of LNGOs.
Conclusion: According to our findings and in the light of literature discussed in this research, a successful relief supply chain depends not only on greater and stronger coordination & collaboration but also on sharing information and resources among LNGOs and INGOs.
|
89 |
Snabb automatiserad benämning som screeninginstrument vid kognitiva störningar : En klinisk studie baserad på AQTBacklund, Josefine, Lindqvist, Anna January 2009 (has links)
<p><em>A Quick Test </em>(AQT)<em> Färg och Form</em> är ett test av snabb automatiserad benämning avsett att detektera kognitiva störningar. Det består av tre delar som var och en utgörs av 40 visuella stimuli som skall benämnas så snabbt som möjligt. Tidigare studier har indikerat att AQT skiljer personer med Alzheimers sjukdom från friska kontroller med högre precision än det ofta använda <em>Mini-Mental-Testet </em>(MMT). I denna studie undersöktes för första gången om AQT-resultat kunde predicera diagnosen hos en konsekutiv serie patienter vid en minnesklinik samt relationen mellan AQT-resultat och biomarkörer (likvorproteiner) för neurodegenerativ sjukdom. 492 svarsblanketter från <em>AQT Färg och Form</em> analyserades och diagnostisk prediktion samt korrelation med nivån av likvorproteiner fastställdes för de 374 första patienterna i serien. Resultaten tyder på att <em>AQT Färg och Form</em> kan vara känsligt för vissa lindriga kognitiva sviktsymptom som förekommer hos personer remitterade för minnesbesvär men inte alltid känsligt för lindriga grader av demens. AQT-data korrelerade måttligt med nivån av patologiska likvorproteiner, troligen avspeglande förhöjda nivåer i Alzheimergruppen. Ytterligare forskning på konsekutiva fallserier behövs för att fastställa testets diagnostiska diskriminationsförmåga i klinisk praxis.</p> / <p><em>A Quick Test </em>(AQT)<em> Color-Form </em>is a test that uses rapid automatized naming in order to identify cognitive impairment. It is divided into three parts, each of which consists of 40 stimuli that are to be named as quickly as possible. Previous studies have indicated that AQT separates patients with Alzheimer’s disease from normal controls with higher accuracy than the commonly used <em>Mini-Mental State Examination </em>(MMSE). The purpose of this study was to investigate, for the first time, whether AQT results collected from a consecutive series of patients at a Memory Clinic would be able to predict the diagnosis. Another aim was to study the possible relation between AQT results and Cerebrospinal Fluid (CSF) biomarkers for neurodegenerative diseases. 492 forms from <em>AQT Color-Form</em> tests were analyzed and diagnostic prediction and correlation with level of CSF biomarkers were determined for the first 374 patients. The results imply that <em>AQT Color-Form</em> may be sensitive to some symptoms of benign memory impairment that is found in patients admitted to a Memory Clinic, but that it is not always sensitive to mild degrees of dementia. Further research consecutive series of patients is needed in order to determine the diagnostic abilities of discrimination in clinical practice.</p>
|
90 |
Vaccine Therapy of Colorectal Cancer Patients with Tumor Associated AntigensUllenhag, Gustav January 2003 (has links)
<p>In this thesis, two different vaccines were evaluated as adjuvant therapy for patients with colorectal cancer. The ability of the two candidate vaccines to generate antigen-specific cellular and humoral responses, respectively, was studied. The effectiveness of granulocyte colony stimulating factor (GM-CSF) as a cytokine adjuvant to augment the immune response was also examined.</p><p>The first vaccination strategy involved immunization with the recombinant tumor-associated protein, carcinoembryonic antigen (CEA). Recombinant CEA was administered at 4 different dose levels 7 times during one year. Peripheral blood samples were regularly analyzed during 36 months. This vaccination regimen induced a strong immunoglobulin 1 (IgG1) and IgG4 response, a moderate IgG2 response and a weak IgG3 response against CEA. GM-CSF markedly augmented the effect on IgG1 and IgG4 as well as the T cell response. In contrast, dose of rCEA had no or modest effect on induced immune responses. The response gradually increased during the 12 months immunization period. Responses of all three IgG subclasses and of T cells were protracted up to 36 months. The anti-CEA IgG titers related significantly to survival. Functional HLA-DR epitopes of CEA could be defined. These major histocompatibility class II epitopes may serve as putative components of a peptide-based vaccination strategy. </p><p>The other vaccine strategy consisted of the tumor-associated antigen epithelial cell adhesion molecule (Ep-Cam) expressed as a transgene in a viral vector, ALVAC. Patients were immunized subcutaneously/intradermally 3 times over 6 weeks and monitored for immune responses for 46 weeks. No anti-Ep-Cam specific humoral response was induced, but Ep-Cam specific type 1 T cells (interpheron-gamma production) were induced, mainly in the GM-CSF group. The cytotoxic cellular response appeared late, or a few months after the last immunization.</p><p>Both vaccines were well tolerated. Since GM-CSF was an important component for both regimens, immungenicity of this cytokine was assessed. Multiple immunizations with low dose GM-CSF were associated with a low incidence of GM-CSF antibodies that did not neutralize the biological effect of GM-CSF. </p><p>In conclusion, both vaccines are promising candidate vaccines. GM-CSF is necessary to induce a strong humoral and cellular immune response. Large clinical trials are urgently warranted to evaluate the clinical efficacy.</p>
|
Page generated in 0.0158 seconds