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Soft tissue sarcoma : biology and therapeutic correlatesHannay, Jonathan A. F. January 2015 (has links)
Soft tissue sarcomas (STS) comprise a heterogenenous group of greater than 50 malignancies of putative mesenchymal cell origin and as such they may arise in diverse tissue types in various anatomical locations throughout the whole body. Collectively they account for approximately 1% of all human malignancies yet have a spectrum of aggressive behaviours amongst their subtypes. They thus pose a particular challenge to manage and remain an under investigated group of cancers with no generally applicable new therapies in the past 40 years and an overall 5-year survival rate that remains stagnant at around 50%. From September 2000 to July 2006 I undertook a full time post-doctoral level research fellowship at the MD Anderson Cancer Center, Houston, Texas, USA in the department of Surgical Oncology to investigate the biology of soft tissue sarcoma and test novel anti- sarcoma adenovirus-based therapy in the preclinical nude rat model of isolated limb perfusion against human sarcoma xenografts. This work, in collaboration with colleagues as indicated herein, led to a number of publications in the scientific literature furthering our understanding of the malignant phenotype of sarcoma and reported preclinical studies with wild-type p53, in a replication deficient adenovirus vector, and oncolytic adenoviruses administered by isolated limb perfusion. Additional collaborative and pioneering preclinical studies reported the molecular imaging of sarcoma response to systemically delivered therapeutic phage RGD-4c AAVP. Doxorubicin chemotherapy is the single most active broadly applicable anti-sarcoma chemotherapeutic yet only has an approximate 30% overall response rate with additional breakthrough tumour progression and recurrence after initial chemo-responsiveness further problematic features in STS management. Doxorubicin is a substrate for the multi- drug resistance (mdr) gene product p-glycoprotein drug efflux pump and exerts its main mode of action by induction of DNA double-strand breaks during the S-phase of the cell cycle. Two papers in my thesis characterise different aspects of chemoresistance in sarcoma. The first shows that wild-type p53 suppresses Protein Kinase Calpha (PKCα) phosphorylation (and activation) of p-glycoprotein by transcriptional repression of PKCα through a Sp-1 transcription factor binding site in its -244/-234 promoter region. The second paper demonstrates that Rad51 (a central mediator of homologous recombination repair of double strand breaks) has elevated levels in sarcoma and particularly in the S- G2 phase of the cell cycle. Suppression of Rad51 with small interfering RNA in sarcoma cell culture led to doxorubicin chemosensitisation. Reintroduction of wild-type p53 into STS cell lines resulted in decreased Rad51 protein and mRNA expression via transcriptional repression of the Rad51 promoter through increased AP-2 binding. In light of poor response rates to chemotherapy, escape from local control portends a poor prognosis for patients with sarcoma. Two papers in my thesis characterise aspects of sarcoma angiogenesis, invasion and metastasis. Human sarcoma samples were found to have high levels of matrix metalloproteinase-9 (MMP-9) with expression levels that correlated with p53 mutational status. MMP-9 is known to degrade extracellular collagen, contribute to the control of the angiogenic switch necessary in primary tumour progression and facilitate invasion and metastasis. Reconstitution of wild-type p53 function led to decreased levels of MMP-9 protein and mRNA as well as zymography-assessed MMP-9 proteolytic activity and decreased tumour cell invasiveness. Reintroduction of wild-type p53 into human sarcoma xenografts in-vivo decreased tumour growth and MMP-9 protein expression. Wild-type p53 was found to suppress mmp-9 transcription via decreased binding of NF-κB to its -607/-595 mmp-9 promoter element. Studies on the role of the VEGF165 in sarcoma found that sarcoma cells stably transfected with VEGF165 formed more aggressive xenografted tumours with increased vascularity, growth rate, metastasis, and resistance to chemotherapy. Use of the anti-VEGFR2 antibody DC101 enhanced doxorubicin sensitivity at sub-conventional dosing, inhibited tumour growth, decreased development of metastases, and reduced tumour micro-vessel density while increasing the vessel maturation index. These effects were explained primarily through effects on endothelial cells (e.c.s), rather than the tumour cells per se, where DC101 induced e.c. sensitivity to doxorubicin and suppressed e.c. production of MMPs. The p53 tumour suppressor pathway is the most frequently mutated pathway in sarcoma. Recapitulation of wild-type p53 function in sarcoma exerts a number of anti-cancer outcomes such as growth arrest, resensitisation to chemotherapy, suppression of invasion, and attenuation of angiogenesis. Using a modified nude rat-human sarcoma xenograft model for isolated limb perfusion (ILP) delivery of wild-type p53 in a replication deficient adenovirus vector I showed that functionally competent wild-type p53 could be delivered to and detected in human leiomyosarcoma xenografts confirming preclinical feasibility - although not efficacious due to low transgene expression. Viral fibre modification to express the RGD tripeptide motif led to greater viral uptake by sarcoma cells in vitro (transductional targeting) and changing the transgene promoter to a response element active in cells with active telomerase expression restricted the transgene expression to the tumour intracellular environment (transcriptional targeting). Delivery of the fibre-modified, selectively replication proficient oncolytic adenovirus Ad.hTC.GFP/ E1a.RGD by ILP demonstrated a more robust, and tumour-restricted, transgene expression with evidence of anti-sarcoma effect confirmed microscopically. Collaborative studies using the fibre modified phage RGD-4C AAVP confirmed that systemic delivery specifically, efficiently, and repeatedly targets human sarcoma xenografts, binds to αv integrins in tumours, and demonstrates a durable, though heterogeneous, transgene expression of 1-4 weeks. Incorporation of the Herpes Simplex Virus thymidine kinase (HSVtk) transgene into RGD-4C AAVP permitted CT-PET spatial and temporal molecular imaging in vivo of transgene expression and allowed quantification of tumour metabolic activity both before and after interval administration of a systemic cytotoxic with predictable and measurable response to treatment before becoming apparent clinically. These papers further the medical and scientific community’s understanding of the biology of soft tissue sarcoma and report preclinical studies with novel and promising anti- sarcoma therapeutics.
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A Comparison of Job Responsibility and Activities between Registered Dietitians with a Bachelor's Degree and Those with a Master's DegreePillow, Stephanie M 17 November 2010 (has links)
Minimal educational requirements for Registered Dietitians (RDs) include a bachelor’s degree and practice program. Recently, a master’s degree was recommended. Studies have not established whether education affects employment. A secondary analysis of 2005 Dietetics Practice Audit data determined whether job responsibility, individuals supervised, and activities differed between 1,626 bachelor’s RDs (B-RDs) and 767 master’s (M-RDs) RDs, registered ≤5 years. Chi-square and ANOVA analyzed differences between B-RDs and M-RDs, at entry-level (0-3 years experience) and beyond-entry-level (3+-5 years experience). Beyond-entry-level B-RDs (31.8%) and entry-level M-RDs (31.9%) reported “supervisor/executive” responsibility more than entry-level B-RDs (26.5%; p=0.01). A higher percentage of M-RDs supervised (29.2%) than B-RDs (24.7%; p=0.02); however, B-RDs supervised more individuals (7.38 ± 4.89) than M-RDs (6.25 ± 4.87; t=2.32; p=0.021). A master’s degree has limited benefits; experience may affect responsibility, individuals supervised, and activities more than education.
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Enhanced pre-clinical assessment of total knee replacement using computational modelling with experimental corroboration & probabilistic applicationsStrickland, Anthony Michael January 2009 (has links)
Demand for Total Knee Replacement (TKR) surgery is high and rising; not just in numbers of procedures, but in the diversity of patient demographics and increase of expectations. Accordingly, greater efforts are being invested into the pre-clinical analysis of TKR designs, to improve their performance in-vivo. A wide range of experimental and computational methods are used to analyse TKR performance pre-clinically. However, direct validation of these methods and models is invariably limited by the restrictions and challenges of clinical assessment, and confounded by the high variability of results seen in-vivo. Consequently, the need exists to achieve greater synergy between different pre-clinical analysis methods. By demonstrating robust corroboration between in-silico and in-vitro testing, and both identifying & quantifying the key sources of uncertainty, greater confidence can be placed in these assessment tools. This thesis charts the development of a new generation of fast computational models for TKR test platforms, with closer collaboration with in-vitro test experts (and consequently more rigorous corroboration with experimental methods) than previously. Beginning with basic tibiofemoral simulations, the complexity of the models was progressively increased, to include in-silico wear prediction, patellofemoral & full lower limb models, rig controller-emulation, and accurate system dynamics. At each stage, the models were compared extensively with data from the literature and experimental tests results generated specifically for corroboration purposes. It is demonstrated that when used in conjunction with, and complementary to, the corresponding experimental work, these higher-integrity in-silico platforms can greatly enrich the range and quality of pre-clinical data available for decision-making in the design process, as well as understanding of the experimental platform dynamics. Further, these models are employed within a probabilistic framework to provide a statistically-quantified assessment of the input factors most influential to variability in the mechanical outcomes of TKR testing. This gives designers a much richer holistic visibility of the true system behaviour than extant 'deterministic' simulation approaches (both computational and experimental). By demonstrating the value of better corroboration and the benefit of stochastic approaches, the methods used here lay the groundwork for future advances in pre-clinical assessment of TKR. These fast, inexpensive models can complement existing approaches, and augment the information available for making better design decisions prior to clinical trials, accelerating the design process, and ultimately leading to improved TKR delivery in-vivo to meet future demands.
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Mechanical and biological augmentation of allograft and synthetic graft in impaction bone graftingBolland, Benjamin J. R. F. January 2008 (has links)
Aims: This thesis has three main aims: • To investigate the potential role of human bone marrow stromal cells (HBMSC) in Impaction Bone Grafting (IBG). • To investigate the potential role of a synthetic graft, Poly (DL-lactic acid), (PDLLA) as a tissue engineering scaffold and a graft extender in IBG. • To investigate methods to improve graft compaction and reduce fracture risk in IBG. Methods: Part I: The biocompatibility and mechanical properties of HBMSC seeded onto allograft or PDLLA were compared to allograft or PDLLA alone in vitro. Part II: Evidence of biocompatibility, neovascularisation and new bone formation in impacted allograft and PDLLA scaffolds seeded with HBMSC, in vivo was assessed and compared to allograft and PDLLA alone. Part III: The laboratory work was translated into the clinical setting with implantation of impacted allograft seeded with HBMSC for the treatment of bone defects in two case studies. Part IV: The role of vibration in IBG technique to reduce fracture risk and improve graft compaction and prosthetic stability was assessed in an in vitro femoral IBG model. Results: Part I: HBMSC seeded onto morsellised allograft or PDLLA, and cultured under osteogenic conditions in vitro were able to withstand the forces equivalent to a standard femoral impaction and were able to differentiate and proliferate along the osteogenic lineage. The living composite formed provided a biomechanical advantage, with increased interparticulate cohesion and shear strength when compared to allograft alone. Part II: HBMSC seeded onto morsellised allograft or PDLLA, impacted and implanted subcutaneously in nude mice demonstrated cell viability and histological evidence of new bone formation and neovascularisation after 28 days. Part III: In two case studies impacted allograft augmented with marrow-derived autogenous cells was used to treat bone voids in the proximal femur. Both patients made an uncomplicated clinical recovery. Imaging confirmed filling of the defects with very encouraging initial graft incorporation. Histochemical staining of graft samples demonstrated that a live composite graft with osteogenic activity had been introduced into the defects. Alkaline phosphatase and immunohistochemical staining techniques confirmed the bone phenotype of the autotransplanted cells. Part IV: Vibration assisted compaction of morsellised allograft reduced the peak loads and hoop strains transmitted to the femoral cortex during graft compaction, improved graft compaction in the proximal and middle femoral regions, which in turn conferred improved mechanical stability of the prosthesis under cyclical loading, demonstrated by a reduction in stem subsidence. Conclusions: • HBMSC when combined with either allograft or synthetic graft (PDLLA) can survive the forces of a standard IBG and under osteogenic conditions, differentiate and proliferate along the osteogenic lineage. HBMSC and allograft / PDLLA composites confer an additional biomechanical advantage over allograft / PDLLA alone. • Increased new bone formation and neovascularisation has been demonstrated in vivo in allograft and PDLLA / HBMSC composites compared to allograft or PDLLA alone. • Tissue engineering principles combining morsellised allograft and HBMSC composites have been utilised to fill bony voids in two clinical cases, with good clinical outcome. • By reducing peak loads, hoop strains and femoral fracture risk, and improving graft compaction and prosthetic stability the use of vibration and a perforated tamp is a potential new safer more flexible IBG technique. • Utilising tissue engineering techniques and improved graft impaction methods provides avenues to augment the biological and mechanical properties of morsellised allograft, and potentially increase the longevity of revision hip arthroplasty performed using the IBG technique.
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Verification of South African Weather Service operational seasonal forecastsMoatshe, Peggy Seanokeng 11 August 2009 (has links)
The South African Weather Service rainfall seasonal forecasts are verified for the period of January-February-March to October-November-December 1998-2004. These forecasts are compiled using different models from different institutions. Probability seasonal forecasts can be evaluated using different skill measures, but in this study the Ranked Probability Skill Score (RPSS), Reliability Diagram (RD) and Relative Operating Characteristics (ROC) are used. The RPSS is presented in the form of maps whereas the RD and ROC are analyses are presented in the form of graphs. The aim of the study is to present skill estimates of operational seasonal forecasts issued at South African Weather Service A limited number of forecasts show positive RPSS value throughout the validation period. From RD and ROC analysis, there is no skill in predicting the normal category as compared to below-normal and above-normal categories. Notwithstanding, the frequency diagrams show that the normal category was often given a large weight in the operational forecasts. The value of verifying seasonal forecast accuracy from the user’s perspective is important. The understanding of seasonal forecast performance helps decision makers to determine when and how to respond to expected climate anomalies. Therefore the frequent update of the seasonal forecast verification is important in order to help Users make better decisions. Copyright / Dissertation (MSc)--University of Pretoria, 2008. / Geography, Geoinformatics and Meteorology / Unrestricted
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Spatio-Temporal Evolution of Rocky Desertification and Its Driving Forces in Karst Areas of Northwestern Guangxi, ChinaYang, Qing qing, Wang, Ke lin, Zhang, Chunhua, Yue, Yue min, Tian, Ri chang, Fan, Fei de 01 September 2011 (has links)
Rocky desertification (RD) is a process of land degradation that often results in extensive soil erosion, bedrock exposure and considerable decrease of land productivity. The spatio-temporal evolution of RD not only reflects regional ecological environmental changes but also directly impacts regional economic and social development. The study area, Hechi, is a typical karst peak cluster depression area in southwest China. Remote sensing, geographic information systems (GIS) and statistical techniques were employed to examine the evolution, including the identification of driving forces, of karst RD in the Northwestern Guangxi. The results indicate that RD became most apparent between 1990 and 2005 when areas of various types of RD increased. Within the karst RD landscape, slight RD was identified as the matrix of the landscape while potential RD had the largest patch sizes. Extremely strong RD, with the simplest shape, was the most influenced by human activities. Overall the landscape evolved from fragmented to agglomerate within the 15-year timeframe. Land condition changes were categorized as five types; desertified, recovered, unchanged, worsened, and alleviated land. The largest turnover within the RD landscape was between slight and moderate RD. With regards to the driving forces all RD had been increasingly influenced by human activities (i. e., the stronger the RD, the stronger the intensity of human disturbances). Dominant impact factors of the RD landscape had shifted from town influence and bare rock land in 1990 to bare rock and grassland in 2005. Moreover, the impacts of stony soil, mountainous proportion and river density on RD increased over time, while that of others decreased. The significant factors included human activities, land use, soil types, environmental geology, and topography. However, only anthropogenic factors (human activities and land use) were reported as leading factors whereas the others acted simply as constraining factors.
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Mötet med dödenWestrin, Maria, Forss, Erik January 2014 (has links)
Forss, E & Westrin, M. Mötet med döden. Hur sjuksköterskor upplever när den yngre palliativa patienten tar upp samtalet om döden – en empirisk studie. Examensarbete i omvårdnad 15 högskolepoäng. Malmö högskola: Fakulteten för Hälsa och samhälle, Institutionen för vårdvetenskap, 2014.Bakgrund: Palliativa patienter blir allt fler inom vården och sjuksköterskor upplever det som stressfyllt att ge omvårdnad till döende patienter på grund av att de känner sig oförberedda. Palliativ vård finns till för att ge patienten ett värdigt liv även när döden närmar sig och inriktar sig inte på någon specifik ålder. Litteratur om döendet handlar om äldre eller barn men inte vuxna i yngre ålder. Det är viktigt att ta reda på hur sjuksköterskor känner när samtalet om döden tas upp med yngre palliativa patienter, för att få ökad kunskap inom det tabubelagda ämnet. Syfte: Att belysa hur sjuksköterskor upplever när den yngre, 18-39 år, palliativa patienten tar upp samtalet om döden. Metod: Empirisk intervjustudie med semistrukturerade frågor. Sex stycken sjuksköterskor intervjuades på Onkologen, Skånes Universitetssjukhus, som har jobbat med unga palliativa patienter. Burnards innehållsanalys (1991) användes som inspiration i resultatarbetet. Resultat: Resultatet visade på att de flesta sjuksköterskorna upplevde att ett samtal om döden med en ung patient väckte ångest hos hen själv. De upplevde att det var svårare att prata med yngre patienter än med äldre då de kunde relatera till sig själva och deras egen dödlighet. De tog upp vikten av att lyssna och bekräfta patienten i den svåra situationen, men även att själva få stöd i det arbete som de utför. Sammanfattning: Det är viktigt att öka kunskapen om hur sjuksköterskan upplever när den yngre patientens uttrycker tankar, känslor och upplevelsen kring döden. Samtalet om döden är ett område som inte tas upp tillräckligt i grundutbildningen utan fokus ligger på en allmän empatisk förmåga. Detta kan leda till att sjuksköterskor har svårt att hantera när ett samtal om döden inträffar. / Forss, E & Westrin, M. Encounter with death. How nurses experience when the younger palliative patient wants to talk about death – an empirical study. Degree Project in nursing 15 credit points, Malmö University: Faculty of Health and Society, Department of Care Science, 2014.Background: Palliative patients increases in health care and nurses find it stressful to provide nursing care to dying patients because they feel unprepared. Palliative care exists to give the patient a dignified life even when death is approaching and does not focus on any specific age. Literature about dying is about the elderly or children but not adults in younger age. It is important to find out how nurses feel when young palliative patient want to talk about death, to increase knowledge of the taboo topic. Aim: To explore how nurses experience when the younger, 18-39 years old, palliative patient wants to talk about death. Method: Empirical interview with semi-structured questions. Six nurses were interviewed at the oncologist, Skånes University Hospital, who has worked with young palliative patients. Burnard content analysis (1991) was used as inspiration in the results work. Results: The results showed that most of the nurses experienced that a conversation about death with a young patient aroused anxiety in herself. They felt that it was more difficult to talk to younger patients than older because they could relate to themselves and their own mortality. They brought up the importance of listening and confirming the patient in the difficult situation, but also to be supported in their work that they perform. Conclusion: It is important to increase the knowledge of how nurses experience when the younger the patient expresses thoughts, feelings and experience surrounding the death. The conversation about death is an area that is not addressed enough in the nurses program; instead the focus is on a general empathy. This can lead to that nurses find it difficult to manage when a conversation of death occurs.
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Performance analysis of routing algorithms of RD-C/TDMA packet radio networks under dynamic random topologyChen, Chien-Ming January 1993 (has links)
No description available.
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Peer-to-Peer Directory Service in Resource Area NetworkNedunchelliyan, Chitra January 2007 (has links)
No description available.
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Nonlinear Optically Active Ionically Self-Assembled Monolayer Thin Films of Organic Polymers Intercalated with an Inorganic Hectorite, Laponite RDShah, Smital S. 03 March 2003 (has links)
Detailed studies are presented of thin films containing a polycation, a nonlinear optically (NLO) active chromophore, and a synthetic hectorite that self-assemble into the noncentrosymmetric structure required for second order nonlinear optical responses. UV/Vis spectroscopy and ellipsometry were used as probes to monitor film growth for upto 25 deposition cycles. Exceptionally homogeneous films were obtained with regular film growth for up to the 25 cycles deposited.
ISAM films self-assemble from polyelectrolyte solutions due to coulombic interactions between a charged substrate and the charged polymer in solution. Charges accumulating at the surface restrict further growth due to charge overcompensation at the surface. The entire process occurs relatively quickly as compared to other competing assembly techniques such as Langmuir-Blodgett assembly and covalent self-assembly.
Previous studies indicated that second harmonic signal diminishes after the deposition of the first few bilayers. This is potentially due to adjacent layer interpenetration, which becomes prominent moving further away from the hard substrate interface. Laponite RD, a synthetic hectorite was introduced in the films in an effort to minimize interpenetration of adjacent bilayers and hence maintain chromophore orientation in every bilayer of the ISAM film. The film was deposited in quadlayers that have the following sequence: Polycation–Laponite–Polycation–Chromophore.
This study is unique in its approach as it investigates the possible implications of film interpenetration on the NLO-activity of ISAM films that can be easily fabricated. It also shows the effects of different interfaces on the NLO-activities of the films.
We have investigated the effect of changing the polycation from poly(allylamine hydrochloride) (PAH) and poly(diallyldimethylammonium chloride) (PDDA) and the solution pH to see how these variables affect the growth and NLO properties of ISAM films. At lower pH values (specify relevant range of values), for both polycations, intrachain and interchain repulsion is strong due to little electrostatic screening. This results in polycation deposition in relatively thin, train-like layers. At higher pH levels (specify relevant range of values here) the electrostatic screening is greater due to a higher effective ionic strength. At these conditions, intrachain and interchain repulsion is reduced and so the polymers adsorb to form thicker layers with more loops and tails than for the case at lower pH. This also results in a higher density of the chromophore in the film.
Extremely smooth surfaces of Laponite RD in film were obtained as confirmed by AFM imaging on glass. Regular quadlayer growth monitored by UV/Vis spectroscopy and ellipsometry was observed for up to 25 quadlayers. Second harmonic generation (SHG) signal was not conclusively affected by the presence of laponite as the decrease of signal was seen after the first few layers in the laponite containing films. This decrease was however was not as sharp in the films containing laponite as in the films that did not contain laponite. It was also noted that the SHG was not so much affected by the number of layers deposited but more so by the distance of the chromophore layer from the hard glass interface. This study thus brings to light the very important effect of the glass interface on the NLO-activity of these films. / Master of Science
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