Engineering

Publication Search Results

Now showing 1 - 9 of 9
  • (2008) Wakefield, Claire; Meiser, Bettina; Gaff, C; Barratt, Anthony; Patel, Minoo; Suthers, G; Lobb, Elizabeth; Ramsay, J; Mann, G
    Journal Article
    Purpose: Despite the established importance of the role of family history in prostate cancer, relatively little research encompasses the psychosocial issues relevant to unaffected men with a family history of prostate cancer. To determine the completeness and quality of available literature on the issues faced by men with a high risk of prostate cancer, we conducted a multidisciplinary review of the literature to provide some guidance on the information that clinicians might provide to men who are concerned about family history. Materials and Methods: A structured literature search was conducted by a multidisciplinary team of clinicians and researchers who reviewed the medical and psychosocial literature, and identified 21 relevant studies. Results: Research suggests that many high risk patients are concerned about the risk of prostate cancer, and some may significantly overestimate that risk. Several studies have shown high screening rates among high risk patients and high levels of interest in genetic testing for prostate cancer risk should it become available, yet many men also report a desire for more information about their personal risk and risk management options. Conclusions: Given the lack of clear data on the efficacy of prostate cancer screening among high risk patients, clinicians could consider providing men who are concerned about family history with information on their personal risk, help them to clarify the potential benefits, limitations and harms of prostate cancer screening in their situation, and then support their choice regarding the management of prostate cancer risk.

  • (2008) Kasparian, Nadine; Meiser, Bettina; Butow, P; Simpson, John; Mann, G
    Journal Article
    Despite rapid advancements in molecular genetics research, little is known about the psychological experiences of individuals with a family history of melanoma. The present study aimed to identify factors contributing to psychological distress among affected and unaffected individuals with a strong family history of melanoma. A total of 121 adults who had recently been informed of the identification of a family-specific mutation in the CDKN2A melanoma susceptibility gene, completed a self-report questionnaire assessing cancer-specific and generalized distress, and a variety of potential predictors. Having a personal history of melanoma (OR = 3.37, p = 0.033), perceiving greater family implications of melanoma (OR = 2.52, p < 0.0001), and the tendency to monitor for threatening information (OR = 3.12, p = 0.008) were associated with melanoma-specific distress. Being childless (beta = 2.09, p = 0.007), perceiving sun exposure as an important cause of melanoma (beta = 1.15, p = 0.015), and perceiving greater family implications of melanoma (beta = 1.02, p = 0.002) were associated with greater generalized anxiety, while monitoring moderated the relationship between endorsement of a genetic model of melanoma and generalized anxiety (p = 0.005). As in other common familial cancers, distress was relatively uncommon in this familial melanoma cohort, even after notification of the presence of a family mutation. Participants do not contemplate their melanoma risk in isolation, but evaluate their risk vis-a-vis the experiences of their relatives.

  • (2008) Meiser, Bettina; Kasparian, Nadine; Mitchell, Penny; Strong, Kathryn; Simpson, John; Tabassum, Laila; Mireskandari, Shab; Schofield, Peter
    Journal Article
    Objectives: This study assesses interest in genetic testing for gene variations associated with bipolar disorder and associated information needs. Methods: Two hundred individuals (95 unaffected and 105 affected with either bipolar disorder, schizoaffective disorder-manic type, or recurrent major depression) from families with multiple cases of bipolar disorder were assessed, using mailed, self-administered questionnaires. Results: The percentage of participants reporting interest in genetic testing was associated with the degree of certainty with which any test would indicate the development of bipolar disorder. Interest in genetic testing, given a 25% lifetime risk scenario, was lowest (with 77% of participants indicating interest), and highest for the 100% lifetime risk scenario (92%). Eighty percent of participants indicated interest in genetic testing of their own children; of these 30% reported wanting their children tested at birth, and 33% in early childhood. Forty-one percent of participants reported that they would be interested in preimplantation genetic diagnosis, and 54% in prenatal testing. Limitations: The possibility of ascertainment bias cannot be ruled out. Interest in hypothetical genetic testing for bipolar disorder may not necessarily translate into actual utilization. Conclusions: These results indicate that uptake of genetic testing for genotyping for low-risk alleles related to bipolar disorder is likely to be lower than for testing for high-penetrance gene mutations that follow Mendelian inheritance. The discrepancy between the desired age of testing children and the accepted current practice may be a source of distress and conflict for parents and health professionals alike.

  • (2000) Cheng, L; Han, Shaowei; Yang, Jia; Zhang, Guangqing; Zhao, Yong
    Conference Paper

  • (2008) Power, M; Marlon, J; Ortiz, N; Bartlein, P; Harrison, Simon; Mayle, F; Ballouche, A; Bradshaw, R; Carcaillet, C; Cordova, C; Mooney, Scott; Moreno, P; Prentice, I; Thonicke, K; Tinner, W; Whitlock, C; Zhang, Yanling; Zhao, Yong; Ali, Amna; Anderson, Richard; Beer, R; Behling, H; Briles, C; Brown, Katherine; Brunelle, A; Bush, M; Camill, P; Chu, G; Clark, J; Colombaroli, D; Connor, Stuart; Daniau, A; Daniels, M; Dodson, John; Doughty, E; Edwards, Meredith; Finsinger, W; Foster, Douglas; Frechette, J; Gaillard, M; Gavin, D; Gobet, E; Haberle, Simon; Hallett, D; Higuera, P; Hope, G; Horn, S; Inoue, J; Kaltenrieder, P; Kennedy, Liz; Kong, Z; Larsen, C; Long, C; Lynch, Jodi; Lynch, E; McGlone, M; Meeks, S; Mensing, S; Meyer, G; Minckley, T; Mohr, J; Nelson, D; New, J; Newnham, R; Noti, R; Oswald, W; Pierce, J; Richard, P; Rowe, C; Goni, M; Shuman, B; Takahara, H; Toney, J; Turney, C; Urrego-Sanchez, D; Umbanhowar, C; Vandergoes, M; Vanniere, B; Vescovi, E
    Journal Article
    Fire activity has varied globally and continuously since the last glacial maximum (LGM) in response to long-term changes in global climate and shorter-term regional changes in climate, vegetation, and human land use. We have synthesized sedimentary charcoal records of biomass burning since the LGM and present global maps showing changes in fire activity for time slices during the past 21,000 years (as differences in charcoal accumulation values compared to pre-industrial). There is strong broad-scale coherence in fire activity after the LGM, but spatial heterogeneity in the signals increases thereafter. In North America, Europe and southern South America, charcoal records indicate less-than-present fire activity during the deglacial period, from 21,000 to ∼11,000 cal yr BP. In contrast, the tropical latitudes of South America and Africa show greater-than-present fire activity from ∼19,000 to ∼17,000 cal yr BP and most sites from Indochina and Australia show greater-than-present fire activity from 16,000 to ∼13,000 cal yr BP. Many sites indicate greater-than-present or near-present activity during the Holocene with the exception of eastern North America and eastern Asia from 8,000 to ∼3,000 cal yr BP, Indonesia and Australia from 11,000 to 4,000 cal yr BP, and southern South America from 6,000 to 3,000 cal yr BP where fire activity was less than present. Regional coherence in the patterns of change in fire activity was evident throughout the post-glacial period. These complex patterns can largely be explained in terms of large-scale climate controls modulated by local changes in vegetation and fuel load.


  • (2022) Gunasekera, Sanjiv
    Thesis
    The arteriovenous fistula (AVF) is a vasculature created for end-stage renal disease patients who undergo haemodialysis. This vasculature is often affected by stenosis in the juxta-anastomotic (JXA) region and the presence of disturbed haemodynamics within the vessel is known to initiate such diseased conditions. A novel treatment involving the implantation of a flexible stent in the JXA region has shown potential for retaining healthy AVFs. Only a limited number of experimental studies have been conducted to understand the disturbed flow conditions, while the impact of stent implantation on the haemodynamics within the AVF is yet to be explored. The study was initiated by developing a benchtop patient-specific AVF model to conduct a Tomographic Particle Image Velocimetry (Tomo-PIV) measurement. The subsequent temporally resolved volumetric velocity field was phase-averaged to quantify fluctuations occurring over the inlet pulsatile conditions. It was noted that high turbulent kinetic energy (TKE) was generated at the JXA region. To study the effects of the stent implantation, Large Eddy Simulations (LES) comparing the AVF geometry with and without the presence of the stent implantation were conducted. The trajectory of the flow in the stented case was funnelled within the stent encapsulated region which in turn, contained the disturbed flow within the stent lumen while mitigating the generation of turbulence. Consequently, the distribution of adverse wall shear stress (WSS) in the stented region was much lower compared to that of the `stent-absent' case. Simulations were also conducted on the diseased patient AVF, before the stent implantation, to make an overall assessment of the effect of treatment. Larger and persistent regions of high TKE were noted in the vessel downstream of the stenosis despite the lower velocity of flow in the diseased model. In summary, the stent implantation in the patient AVF showed the ability to funnel flow disturbances away from the vessel wall, thereby leading to lower adverse WSS distributions. The presence of the stent also mitigated turbulence generation. These findings provide valuable insight into the favourable haemodynamic effects of this novel endovascular procedure, thus, substantiating this treatment strategy to treat vascular disease in AVFs.

  • (2022) Kokkinos, John
    Thesis
    Less than 10% of patients with pancreatic ductal adenocarcinoma (PDAC) survive more than 5 years. One of the characteristic features that drive the aggressive nature of PDAC is its multicellular, heterogeneous, and fibrotic microenvironment. We previously identified a cytoskeletal protein, βIII-tubulin, as a novel therapeutic target in PDAC. However, the PDAC cell survival mechanisms controlled by βIII-tubulin were previously unknown. We also identified a major gap in the ability of human PDAC preclinical models to accurately mimic the 3D multicellular architecture and stroma of the disease. Thus, the aims of this work were (1) to evaluate the pro-survival role of βIII-tubulin in PDAC; (2) to establish a new patient derived tumour explant model that maintains all features of the PDAC microenvironment; and (3) to use the tumour explant model to test the clinical potential of silencing βIII-tubulin expression as well as two stromal targets that had been previously explored by our lab: solute carrier 7A11 (SLC7A11) and heat shock protein 47 (HSP47) Here, we identified that silencing βIII-tubulin in pancreatic cancer cells activated extrinsic apoptosis and increased their sensitivity to extrinsic apoptosis inducers including tumour necrosis factor-α (TNFα), Fas-ligand (FasL), and TNF-related apoptosis inducing factor (TRAIL). We next established the patient derived PDAC tumour explant model. We cultured whole-tissue tumour explants from PDAC patients for 12 days and demonstrated that explants maintained their 3D multicellular architecture, proliferative state, and collagen fibrosis. We also demonstrated the ability to deliver chemotherapeutics and siRNA-nanoparticles to the tumour explants. Finally, we tested the utility of this model to investigate the clinical potential of silencing three different therapeutic targets. We showed that therapeutic silencing of βIII-tubulin combined with TRAIL increased extrinsic apoptosis, decreased cell proliferation, and decreased tumour cell number. Inhibition of the stromal target SLC7A11 reduced tumour cell number and inhibited activity of stromal cancer-associated fibroblasts. Silencing of another target, HSP47, also led to a reduction in tumour cells and decreased cell proliferation. Overall, this work has discovered a previously unexplored role of βIII-tubulin as a brake on extrinsic cell death and has developed a new human PDAC preclinical model with utility in the drug development and precision medicine pipeline.

  • (2021) Ng, Olivia
    Thesis
    The arteriovenous fistula (AVF) is a surgically-made vascular structure connecting an artery to a vein. It is the optimal form of vascular access for haemodialysis-dependent end-stage renal disease patients. However, AVF are prone to access dysfunction through the formation of stenoses, which compromise the structure’s utility. To date, a plethora of clinical models are used to predict AVF formation failure based on patient factors and other models predicting late AVF failure by assessing haemodynamics and quantifying disturbed flow behaviours and wall shear stress metrics with stenosis formation. That said, inconsistencies were identified in the correlation between these metrics and diseased AVFs. This thesis aims to assess the suitability of another haemodynamic-related metric, resistance, derived from pressure drop and flow rates through patient-specific CFD modelling, for diagnosing and predicting AVF failure. A three-dimensional ultrasound scanning system was used to obtain patient-specific geometry and flow profiles, used for CFD models which were then analysed, with resistance calculated for each patient. The significance of patient-specific CFD modelling was demonstrated in its usefulness to generate a patient-targeted indicator of diseased AVF. To study the effectiveness of resistance as a metric, the relationship between CFD-derived resistance and the potential for AVF failure was evaluated, starting with classification of resistance results among patients who had undergone treatment for stenosis. An exploratory study into the suitability of CFD-derived resistance and its association with patients’ AVF conditions was further conducted by classifying data from a larger patient dataset and fitting the classified data to a multilevel regression model. CFD-derived resistance was found to be higher at the proximal vein of problematic AVF, however this figure was 76% lower among patients who had undergone stenosis treatment. Meanwhile, no correlation was found between resistance at the proximal artery and patency status. An area under curve of 92.1% was found from the receiver operating characteristic analysis, noting an outstanding discrimination of the classification. CFD-derived resistance appears to be a promising metric in the assessment of a suitable diagnostic marker for AVF failure. This research concludes with aspirations for clinical implementation of a related system, alongside routine surveillance of AVF.