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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.
691

MRI-Guided Prostate Motion Tracking using Multislice-to-Volume Registration

TADAYYON, HADI 13 July 2010 (has links)
MRI-guided prostate needle biopsy requires compensation for organ motion between target planning and needle placement. Two questions are studied and answered in this work: is rigid registration sufficient in tracking the targets with a maximum error of 3 mm (smaller than average prostate tumor size) and how many intra-operative slices are required to obtain this accuracy? We developed rigid and deformable multislice- to-volume registration algorithms for tracking the biopsy targets within the prostate. Three orthogonal plus additional transverse intra-operative slices were acquired in the approximate center of the prostate and registered with a high-resolution target planning volume. Simulated intra-operative data, phantom data, and MRI-guided robotic prostate biopsy data were used to assess tracking accuracy. Registration tests on simulated intra-operative data with 3, 4, and 5 slices were performed to evaluate the effect on registration error and time. Results: Using three orthogonal slices pro- vides sufficient accuracy. Convergence test results on phantom images demonstrated 100% success rate for initial misalignment of 5mm. Average registration errors for the patient data were 2.55mm and 2.05mm for the rigid and deformable algorithms, respectively. The algorithm was able to capture rigid biopsy target displacements of maximum 8mm and non-rigid displacements of maximum 1.5mm. Rigid tracking appears to be promising. Deformable registration does not seem warranted. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-07-13 16:41:52.223
692

Association between Proposed Quality of Care Indicators and Long-Term Outcomes for Men with Localized Prostate Cancer

WEBBER, COLLEEN ELIZABETH 08 September 2011 (has links)
Background: We evaluated the validity of a set of 11 quality indicators for prostate cancer radiotherapy and radical prostatectomy by examining their association with outcomes. The selected indicators were: hospital volume, pre-treatment risk assessment, patient consultation with a radiation oncologist, appropriate follow-up care, leg immobilization during radiotherapy, bladder filling during radiotherapy, portal film target localization, use of nerve sparing surgery, operative blood loss, margin status and pelvic lymph node dissection. The selected outcomes were: cause-specific survival, disease-free survival, late morbidity (urinary incontinence, gastrointestinal and genitourinary morbidity), change in node stage from clinical N0 to pathologic N1, and margin status. Methods: Our study sample consisted of 1570 prostate cancer patients who were diagnosed in Ontario between January 1, 1990 and December 31, 1998 who received radical prostatectomy within 6 months of diagnosis (n=646), or curative radiotherapy within 9 months of diagnosis (n=924). Quality of care, outcomes, and potential confounders were measured using patient chart and administrative data. Regression techniques were used to evaluate the associations between quality indicators and relevant outcomes. Results: For patients treated surgically, hospital volume met our test of validity. Patients treated in the lowest volume hospital (0-1 RP/month) were at greater risk of prostate cancer death than patients treated in the highest volume hospitals (7+ RP/month) (HR=5.37 95% CI=1.23-23.46). For patients treated with radiotherapy, leg immobilization and bladder filling during radiotherapy met our test of validity. Patients treated without leg immobilization were more likely to experience urinary incontinence (RR=2.18, 95% CI=1.23-3.87) and genitourinary late morbidities (RR=1.72, 95% CI=1.16-2.56) than patients who received leg immobilization. Patients who were treated with an empty bladder were more likely to experience GU late morbidities (RR=1.98, 95% CI=1.08-3.63) than those treated with a full bladder. The remaining indicators did not meet our test of validity. Conclusion: Our results support the validity of one surgical quality indicator and two radiotherapy quality indicators. Explanations for our non-significant findings, including limited study power, data quality, our definition and measurement of indicators, and a true failure to predict outcome(s) are discussed, and recommendations for further research are presented. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2011-09-07 20:26:34.461
693

Barley and flax hull ingredients as functional foods

Hao, Meili 22 September 2010 (has links)
The purpose of the research was to investigate the potential for converting agricultural by-products, barley hull and flaxseed hull as well as their co-extract, into value-added functional food ingredients. Four varieties of barley hull and 3 types of flaxseed hull were hydrolyzed in calcium hydroxide solution in a water bath at 70°C for 4 hrs with shaking. The major phenolic compounds in barley hull, flaxseed hull and their co-extracts were identified by reversed phase high performance liquid chromatography (HPLC) coupled with photodiode array detection (PAD) and quadrupole - time of flight (Q-TOF) mass spectrometry (LC-MS). Ferulic acid, p-coumaric acid, vanillic acid and vanillin, and four ferulate dehydrodimers were detected in barley hull and their co-extracts. Quantitative analysis was conducted on the phenolic acids using the available standards. However, the phenolic compounds in flaxseed were found to be distinct from that of barley hull. Large amounts of secoisolariciresinol diglucoside (SDG), ferulic acid glucoside (FeAG), p-coumaric acid glucoside (CouAG) were found in flaxseed hull with minor content of caffeic acid glucoside (CAG) and flavonoids herbacitin glucoside (HDG), whereas the phytochemical profile of the co-extract was enriched by combining major phenolic compounds from both barley hull and flaxseed hull.The antioxidant activity of barley hull, flaxseed hull as well as their co-extract was evaluated using DPPH radical scavenging assay while total phenolic content was measured using the Folin-Ciocalteau method. After screening using chemical assays, the representative barley hull extract, flaxseed hull extract as well as their co-extract were tested for their intracellular antioxidant activity and the antiproliferative activity in PC-3 human prostate cancer cells. Both chemical assays and the cell culture assays indicated that barley and flaxseed hull had strong antioxidant activity and antiproliferative activity. Although the co-extract exhibited the strong antioxidant activity in the chemicals assay, it behaved differently in the cell culture assay, which may be attributed to the chemical and biological properties of the major phenolics in the co-extract.Following evaluation of the antioxidant activity and anticancer effect of barley hull extract, flaxseed hull extract as well as their co-extract, each type of extract was incorporated into Chinese steamed bread (CSB). The phytochemical profile of CSB was enriched by incorporating barley hull extract, flaxseed hull extract as well as their co-extract, which resulted in a significant enhancement in the antioxidant activity evaluated by DPPH and ORAC. Therefore, barley hull, flaxseed hull and their co-extract are suggested as promising sources of functional food ingredients.
694

COFILIN NAVIGATES CELLULAR CYTOSKELETON AND INVASION RESPONSES TO TGF-β TOWARDS PROSTATE CANCER METASTASIS

Santiago, Joanne Collazo 01 January 2013 (has links)
Cofilin’s activity to nucleate actin filament assembly, is regulated by phosphorylation at a single site on the amino terminus, Serine 3. Phosphorylation at this site abolishes the ability of ADF/cofilin to bind to F-actin and inhibits its severing function. This work characterizes the ability of dephosphorylated cofilin (mutation at Serine 3 site) to navigate prostate cancer actin cytoskeleton and metastatic properties in response to TGF-β. TGF-β increased Lim Domain Kinase 2 (LIMK-2) activity leading to cofilin phosphorylation and decrease actin filament severing in wild type cofilin (WTCFL) PC-3 cells. Constitutively active cofilin in Serine 3 cofilin mutants (S3ACFL) promoted prostate cancer cell filopodia formation, actin severing and directed TGF-β mediated migration and invasion. Co-culture of prostate cancer cells with prostate cancer associated fibroblasts induced cell invasion in WTCFL and S3ACFL cells. Active cofilin further enhanced the invasive response, even in the presence of a TGF-β-neutralizing antibody, implicating the contribution of the microenvironment. Active cofilin led to a significant increase in prostate cancer cell metastatic potential in vivo and cofilin correlated with metastasis in a mouse model of prostate tumor progression. In human prostate cancer, cofilin expression was significantly higher in metastasis compared to the primary tumors. Cofilin thus emerges as a regulator of the actin cytoskeleton remodeling capable of coordinating the cellular responses to TGF- β towards prostate cancer metastasis. Understanding how cancer cells interprete TGF-β signals from the microenvironment, is critical for defining the mechanism via which TGF- β function is switched from a growth suppressor to a metastasis promoter. Here we show that in prostate cancer, TGF-β action is directed by active cofilin enabling actin cytoskeleton changes and metastatic behavior. The significant association of cofilin with prostate cancer metastatic progression supports its predictive and targeting value in metastasis.
695

The effect of fill density on rectal balloon dosimetry

Teye, Vida Dede 04 May 2013 (has links)
Access to abstract permanently restricted to Ball State community only. / Literature review -- Interaction of radiation with matter -- Radiation dosimetry -- Materials and methods -- Results -- Discursion. / Access to thesis permanenty restricted to Ball State community only. / Department of Physics and Astronomy
696

Metformin and Prostate Cancer among Diabetic Men

Margel, David 19 June 2014 (has links)
Background: This thesis is composed of three studies. In the first paper, we tested the association of metformin use with prostate cancer incidence. In the second paper, we examined the association of metformin use with all-cause and prostate cancer specific mortality. The final paper explored the benefit of detailed pathology review to predict mortality among diabetic men with prostate cancer. Methods: A total of 5306 incident diabetic men older than 66 who subsequently developed prostate cancer were identified using the Ontario Diabetes Database and the Ontario Cancer Registry between 1994-2008. The association of metformin use and risk of prostate cancer and its grade was tested with a nested case-control design using a conditional logistic regression model. We used a cohort design with a time dependent Cox-proportional hazard model to examine the association of metformin use and mortality. Finally, we employed a c-statistic and Net Reclassification Improvement analysis to study the impact of pathology abstraction on predicting mortality. Results: The data suggest metformin use was not associated with the risk of prostate cancer or its grade at presentation. However, each additional 6 month of metformin use was associated with a 24% decrease in prostate-cancer-specific and 8% decrease in all-cause mortality. Pathology abstraction improved the accuracy in predicting all-cause and prostate-cancer specific mortality. Conclusions: In our study metformin use was not associated with a decreased risk of prostate cancer, but had a significant impact on all-cause and prostate cancer specific mortality. These results may serve as proof of concept in designing an interventional study of metformin to delay progression in prostate cancer.
697

Metformin and Prostate Cancer among Diabetic Men

Margel, David 19 June 2014 (has links)
Background: This thesis is composed of three studies. In the first paper, we tested the association of metformin use with prostate cancer incidence. In the second paper, we examined the association of metformin use with all-cause and prostate cancer specific mortality. The final paper explored the benefit of detailed pathology review to predict mortality among diabetic men with prostate cancer. Methods: A total of 5306 incident diabetic men older than 66 who subsequently developed prostate cancer were identified using the Ontario Diabetes Database and the Ontario Cancer Registry between 1994-2008. The association of metformin use and risk of prostate cancer and its grade was tested with a nested case-control design using a conditional logistic regression model. We used a cohort design with a time dependent Cox-proportional hazard model to examine the association of metformin use and mortality. Finally, we employed a c-statistic and Net Reclassification Improvement analysis to study the impact of pathology abstraction on predicting mortality. Results: The data suggest metformin use was not associated with the risk of prostate cancer or its grade at presentation. However, each additional 6 month of metformin use was associated with a 24% decrease in prostate-cancer-specific and 8% decrease in all-cause mortality. Pathology abstraction improved the accuracy in predicting all-cause and prostate-cancer specific mortality. Conclusions: In our study metformin use was not associated with a decreased risk of prostate cancer, but had a significant impact on all-cause and prostate cancer specific mortality. These results may serve as proof of concept in designing an interventional study of metformin to delay progression in prostate cancer.
698

Barley and flax hull ingredients as functional foods

Hao, Meili 22 September 2010 (has links)
The purpose of the research was to investigate the potential for converting agricultural by-products, barley hull and flaxseed hull as well as their co-extract, into value-added functional food ingredients. Four varieties of barley hull and 3 types of flaxseed hull were hydrolyzed in calcium hydroxide solution in a water bath at 70°C for 4 hrs with shaking. The major phenolic compounds in barley hull, flaxseed hull and their co-extracts were identified by reversed phase high performance liquid chromatography (HPLC) coupled with photodiode array detection (PAD) and quadrupole - time of flight (Q-TOF) mass spectrometry (LC-MS). Ferulic acid, p-coumaric acid, vanillic acid and vanillin, and four ferulate dehydrodimers were detected in barley hull and their co-extracts. Quantitative analysis was conducted on the phenolic acids using the available standards. However, the phenolic compounds in flaxseed were found to be distinct from that of barley hull. Large amounts of secoisolariciresinol diglucoside (SDG), ferulic acid glucoside (FeAG), p-coumaric acid glucoside (CouAG) were found in flaxseed hull with minor content of caffeic acid glucoside (CAG) and flavonoids herbacitin glucoside (HDG), whereas the phytochemical profile of the co-extract was enriched by combining major phenolic compounds from both barley hull and flaxseed hull.The antioxidant activity of barley hull, flaxseed hull as well as their co-extract was evaluated using DPPH radical scavenging assay while total phenolic content was measured using the Folin-Ciocalteau method. After screening using chemical assays, the representative barley hull extract, flaxseed hull extract as well as their co-extract were tested for their intracellular antioxidant activity and the antiproliferative activity in PC-3 human prostate cancer cells. Both chemical assays and the cell culture assays indicated that barley and flaxseed hull had strong antioxidant activity and antiproliferative activity. Although the co-extract exhibited the strong antioxidant activity in the chemicals assay, it behaved differently in the cell culture assay, which may be attributed to the chemical and biological properties of the major phenolics in the co-extract.Following evaluation of the antioxidant activity and anticancer effect of barley hull extract, flaxseed hull extract as well as their co-extract, each type of extract was incorporated into Chinese steamed bread (CSB). The phytochemical profile of CSB was enriched by incorporating barley hull extract, flaxseed hull extract as well as their co-extract, which resulted in a significant enhancement in the antioxidant activity evaluated by DPPH and ORAC. Therefore, barley hull, flaxseed hull and their co-extract are suggested as promising sources of functional food ingredients.
699

Design and Development of a Personal Health Record System for Prostate Cancer Patients

Razavi, Avesta 16 December 2013 (has links)
There is a growing demand to involve patients in their own healthcare. Personal Health Records are among the most promising tools for this purpose. However, these tools need to meet patients’ needs and interests in order to be fully adopted and successfully used. This study takes a user centered design approach to design and develop a personal health record for prostate cancer patients by involving them in two main activities of a user centered design: requirements gathering and evaluation. The first phase of the study uses content analysis to analyze interviews with patients and elicit their needs and concerns. Results of this phase showed that patient’s information needs are different depending on the stage of the disease. Before starting treatment, patients are more interested in information about different methods of treatment and their potential side effects. However, after treatment, patients mostly need information about the management of treatment complications and the long term follow ups of their disease. Results also showed that the Internet is the most common information source for patients to find information. However, patients expressed concerns regarding the credibility and reliability of information they found on the Internet. The majority of patients also showed interest in accessing their medical records. However, some patients were concerned about the understandability of the information. Also, there was some concern regarding electronic access to medical records and security of personal data. The findings from phase one are used in phase two to modify a preliminary prototype of the system. In phase three, the modified prototype is evaluated by undergoing usability testing. Overall, the results of usability testing showed that the system was generally useful and easy to use. However, a number of issues were identified that could be resolved in the next iteration of its design and development. / Graduate / 0984
700

Development of Novel Protein-Based MRI Contrast Agents for the Molecular Imaging of Cancer Biomarkers

Pu, Fan 18 December 2014 (has links)
Temporal and spatial molecular imaging of disease biomarkers using non-invasive MRI with high resolution is largely limited by lack of MRI contrast agents with high sensitivity, high specificity, optimized biodistribution and pharmacokinetics. In this dissertation, I report my Ph. D. work on the development of protein-based MRI contrast agents (ProCAs) specifically targeting different cancer biomarkers, such as grastrin-releasing peptide receptor (GRPR), prostate specific membrane antigen (PSMA), and vascular endothelial growth factor receptor-2 (VEGFR-2). Similar to non-targeted ProCAs, these biomarker-targeted ProCAs exhibit 5 - 10 times higher r1 and r2 relaxivites than that of clinical MRI contrast agents. In addition, these biomarker-targeted ProCAs have high Gd3+ binding affinities and metal selectivities. The highest binding affinity of the three GRPR-targeted contrast reagents obtained by grafting a GRPR ligand binding moiety into ProCA32 for GRPR is 2.7 x 10-9 M. We further demonstrate that GRPR-targeted ProCAs were able to semi-quantitatively evaluate GRPR expression levels in xenograft mice model by MRI. In addition, we have also created a PSMA-targeted ProCA which has a binding affinity to PSMA biomarker of 5.2 x 10-7 M. Further, we developed VEGFR-targeted contrast agent which is able to image VEGFR2 in mice models using T1-weighted and T2-weighted sequences. Moreover, the relaxivities and coordination water numbers of ProCAs can be tuned by protein design of ProCA4. Since disease biomarkers are expressed in various tumors and diseases, our results may have strong preclinical and clinical implications for the diagnosis and therapeutics of cancer and other type of diseases.

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