No description available.

<p>Despite clear cell renal cell carcinoma (ccRCC) being the most common and one of the most lethal forms of RCC, our understanding of ccRCC tumourigenesis remains limited. To identify factors contributing to ccRCC formation, we have found that raf kinase inhibitor protein (RKIP) is a candidate tumour suppressor of ccRCC. This is consistent with publications implicating that RKIP possesses tumour suppression functions in several human cancers. However, whether RKIP suppresses ccRCC tumorigenesis has yet to be determined. This thesis was therefore undertaken to examine the role of RKIP in the tumourigenesis of ccRCC as well as to gain knowledge about this understudied area of kidney cancer research. Upon examination of more than 600 patients with ccRCC in several independent patient cohorts, levels of RKIP protein are significantly reduced in more than 80% of ccRCC tumours in comparison to the adjacent non-tumour kidney or normal kidney tissues. This observed magnitude of RKIP reduction strongly suggests that RKIP is an important tumour suppressor of ccRCC. Supporting this concept is observations that ectopic expression of RKIP inhibited A498 and 786-O ccRCC cell invasion. Conversely, knockdown of RKIP in A498 and 786-O cells enhanced the invasion ability of those cells. Additionally, the progression of ccRCC into advanced tumour stages and tumour grades is correlated with a reduction in RKIP protein. This reduction of RKIP protein levels is more apparent in metastasized ccRCC tumours in which all tumours were negative for RKIP protein expression in comparison to the matched organ-confined tumours. To date there have been no reports investigating the role of RKIP in renal cell carcinoma, our results demonstrate a strong relationship between RKIP reduction and progression of this often fatal disease.</p> / Master of Science (MSc)

<p>The majority (75%) of renal cell carcinoma (RCC) is comprised of clear cell renal cell carcinoma (ccRCC). Despite ccRCC being the most aggressive form of RCC, our knowledge regarding the pathogenesis of the disease remains limited. We have identified upregulation of the extracellular protein periostin (POSTN) in ccRCC. Western blot analysis of ccRCC tumours from 27 patients demonstrated high POSTN protein expression in 26 tumours compared to their respective adjacent normal kidney tissue (ANK). Immunohistochemistry (IHC) analysis revealed high levels of stromal POSTN protein in the ccRCC primary tumours and 16 metastasized ccRCCs. Intriguingly, abundant stromal POSTN in the tumour and non tumour boundary were observed in local and metastaized ccRCC, and in A498 ccRCC cell-derived xenograft tumours. Collectively, these results suggest that the ccRCC-associated POSTN was derived from the stroma. This notion was supported by the co-existence of POSTN with α-smooth muscle actin (αSMA) in both local and metastasized ccRCC tumours. αSMA is a marker of activated stromal fibroblasts (myofibroblasts). Furthermore, co-culture of NIH3T3 murine fibroblasts with human A498 or 786-0 ccRCC cells dramatically enhanced POSTN transcription and secretion from NIH3T3 cells. Extracellular POSTN significantly enhanced A498 cell attachment. Upregulation of POSTN in NIH3T3 cells enhanced their proliferation. Taken together, my research demonstrates that 1) ccRCC induces fibroblast-mediated accumulation of extracellular POSTN, 2) stromal POSTN enhances ccRCC attachment, and 3) high levels of POSTN promotes fibroblasts' proliferation. These observations suggest a critical role for POSTN in mediating the co-evolving process between ccRCC and its stroma during ccRCC pathogenesis.</p> / Master of Science (MSc)

<p>Objective: The design of a prototype avalanche photodiode gamma camera and an adaptable and expandable acquisition board. To test the performance of the acquisition board a photomultiplier base camera is constructed and utilized in various configurations. The APD-based gamma camera is tested on the same acquisition board to evaluate its performance.</p> <p>Results:Spectra have been collected and analyzed utilizing four various detector/system configurations. i) a PET module, utilizing a PMT coupled to a pixilated BGO crystal with a high energy Na-22 source. ii) a single PMT extracted from a PET module akin to the one mentioned previously and coupled to NaI(T1) with a Co-57 source. iii) the same PMT coupled to a CsI(T1) crystal with a variety of sources, including Tc-99m, Ga-67 and Co37. iv) an APD coupled to a CsI(T1) crystal with a variety of sources including Tc-99m and Co-57. Images have been collected from multiple camera configurations, all by a 2 by 2 array. APD's with CsI(T!), PMT's and NaI(T1) and a PET module with PMT's on BGO</p> <p>Conclusion: These requirements have been met with the current design and the system has been tested in a controlled environment. collecting spectrum while operating a single channel and for some configurations, images were collected operating a multi-channel array. A number of steps can be taken to improve upon this prototype, The detector itself may benefit from a pixilated crystal and current APD technology. The acquisition board should be transferred to a multiple printed circuit board design allowing it to be implemented ill a black-box manner. Additionally. the current USB bridge' limits the transfer rate of data between the DSC and the' PC. as a result. alternatives should be investigated.</p> / Master of Science (MSc)

Master of Science (MS)

<p>With advances in neonatal intensive care, many infants born at risk due to very low birthweight (1500 grams or less), due to intrauterine growth retardation (the small-for-gestational age infant has a birthweight less than 2 SD below the mean for gestation) or due to severe Respiratory Distress Syndrome and birth asphyxia, survive free of major debilitating sequelae. However, these apparently 'healthy' children may experience difficulties in perceptual, cognitive and academic performance. The early language development of 12 'healthy' children potentially at risk due to their pre- and perinatal histories, and a group of comparison children matched for sex and social class was investigated. Their language was recorded at home at three monthly intervals during a rapid phase of acquisition (18 to 30 months), to determine whether the two populations were acquiring language similarly. Of further interest was the ambient linguistic environment provided by their mothers. The language measures, derived from the child's spontaneous speech, quantified verbal output (rate and amount of speech), syntactic complexity (mean length of utterance, upper bound and type-token ratio) and morphemic acquisition. Comprehension and expressive scores were also derived from the Reynell Language Scales. The mothers' speech was scored for verbal output and syntactic complexity. The high risk children were as verbose as the comparison children, but their language was syntactically less complex. Their comprehension scores were also significantly lower. Although the high risk scores (uncorrected for the degree of prematurity) were within normal range, they were still significantly below those of the comparison children. This, along with the fact that the language of the two groups of mothers did not differ, and the fact that social class was not a significant factor, supports the position that maturational delay and/or cortical lesion may affect language acquisition. Other issues discussed included the propriety of applying a correction for prematurity to the results, and whether the results are evidence of a developmental lag, or a continuing disability likely to affect other emerging skills. Finally, this study provided correlations between language measures derived from spontaneous speech, and those from standardised language scales.</p> / Doctor of Philosophy (PhD)

Obesity can have numerous detrimental consequences, namely metabolic syndrome, type 2 diabetes, cardiovascular disease, cancer, and Alzheimers disease. The pathogenesis and physiologic consequences of obesity are unknown, but they are often associated with increased inflammation and oxidative stress in both the body and in the brain. One factor that has been implicated in causing inflammation associated with a high fat diet is the enzyme NADPH oxidase, or NOX, specifically the subunit NOX2. Two studies were performed in order to assess the effects of a high fat diet in combination with a universal NOX2 deficiency and a NOX2 deficiency targeted to macrophages. The results of the first study indicate that the NOX2 knockout (NOX2KO) mice on a high fat diet do not experience all the deleterious metabolic and inflammatory effects in the body and brain to the same degree as wild-type mice. This suggests that a deficiency in NOX2 does offer protection from some of the deleterious effects of a high fat diet. It was also determined from the first study that NOX2 expression is localized to macrophages in the visceral adipose tissue. In order to target these macrophages, a second study was conducted. For this second study, a mouse model was genetically engineered with the intent of inhibiting NOX2 solely within macrophages. Similar to the first study, these macrophage-deficient NOX2 knockout (macNOX2KO) mice were placed on a high fat along with the NOX2-flox wild-type (WT-FL) mice. The results suggest that the macrophage-deficient NOX2 knockout mice were protected from the deleterious effects of a high fat diet. In summary, the deletion of NOX2 appears to offer a protective benefit against the deleterious effects of obesity in the context of a high fat diet. Specifically, the deletion of NOX2 in macrophages also offers this protection with the added benefit of targeting the deletion so as to not affect NOX2 functioning in other cells in the body.

Spotted fever group (SFG) Rickettsia are primarily associated with their reservoir host and vector, the tick. Rickettsial colonization and maintenance within the arthropod is a key component of vector competence and pathogen transmission to the mammalian host. Contemporary detection of novel tick hosts for rickettsial species, combined with an unprecedented rise in human cases of SFG rickettsiosis, necessitates a deeper understanding of tick/Rickettsia interactions. The hypothesis for this work is that if primary tick/Rickettsia pairings do not exist then rickettsial determinants account for primary vector/pathogen relationships. To this end, Dermacentor variabilis and Amblyomma maculatum ticks were exposed to R. rickettsii, R. parkeri, R. montanensis, R. amblyommii or R. felis. Rickettsial exposure negatively impacted the fitness of A. maculatum, but not D. variabilis. Transovarial and transtadial transmission of rickettsiae was most successful for R. amblyommii and R. parkeri in both, A. maculatum and D. variabilis eggs, larvae, and nymphs. Maintenance of rickettsiae in both tick species via transstadial transmission was diminished from unfed larvae to unfed F1 adults. To further investigate the maintenance of Rickettsia in the arthropod host, an in vitro and in vivo model of R. parkeri infection was utilized. Rickettsial proteins implicated in intracellular actin-based motility (Sca2 and RickA) were shown to function similarly in mammalian and tick cell culture, suggesting conserved functionality in both hosts. In vivo dissemination of a wild-type strain of R. parkeri was measured against two strains deficient in Sca2 and RickA expression. Wild-type, RickA, and Sca2 deficient strains R. parkeri persisted in all tick organs organs at 7 days post-exposure. The findings suggest transovarial transmission specificity to be tick species dependent and vertical transmission is not sustainable.

Ticks are important worldwide as vectors of bacteria, viruses, and parasites. Pathogenic and non-pathogenic Spotted fever group (SFG) Rickettsia are maintained and transmitted by ticks with specific hard tick-Rickettsia pairings evident in nature. The pathogenic SFG Rickettsia rickettsii is transmitted by the hard tick Dermacentor variabilis. In response to infection, D. variabilis is known differentially respond to SFG Rickettsia infection. The mechanisms of differential immune induction are currently unknown, and are likely involved in the establishment of specific tick-SFG Rickettsia pairings. It was hypothesized that the level of response by D. variabilis to SFG Rickettsia occurs in a species-specific manner, and that this response drives vector competence. To this end, we report the isolation of an mRNA transcript, dvrelish, using RACE-PCR. Conserved domain analysis of dvrelish identified a Rel-homolgy domain, allowing for its identification as encoding a putative Relish-type NF-κB protein. DvRelish was identified via Western blot, immunofluorescence assay and MALDI-TOF/TOF mass-spectrometry. Tick infection assays were performed using microinjection and capillary feeding technique methodologies to identify dvrelish expression in response to SFG Rickettsia infection. Microinjection of 107 R. rickettsii induced the increased expression of dvrelish in hemocytes at 1 hour post injection, and in combined tissues at 6 hours post injected. Injection with similar and lower doses of P. aeruginosa and Rickettsia parkeri did not significantly change dvrelish expression. When capillary fed R. rickettsii, dvrelish expression increased in hemocytes after 1 hour exposure and decreased after a 3 hour exposure. Together, the expression of dvrelish was dose and tissues specific in response to SFG Rickettsia challenge. Understanding the molecular regulation of immunological response to rickettsial infection in ticks may better define the mechanisms of vector competence and the epidemiology of SFG rickettsioses.

Transmission-blocking vaccines (TBVs) target Plasmodium parasite sexual stages, aiming to block further development of the parasite within the mosquito host. Plasmodium falciparum zygote/ookinete surface protein Pfs25 is one of the leading TBV candidate antigens and antibodies against Pfs25 have been shown to exhibit complete transmission-blocking activity in pre-clinical studies. Phase 1 human clinical trials have revealed that Pfs25 was a poor immunogen in humans in the formulations tested and high titers of anti-Pfs25 antibodies are required to achieve good transmission-blocking activity in the ex vivo standard membrane feeding assay which measures the functional activity of the antibodies induced. Work in this thesis describes the production of recombinant monomeric Pfs25 protein, Pfs25 based particulate vaccines (Pfs25-IMX313 nanoparticle, Pfs25-HBsAg VLP and Pfs25-Q&beta; VLP) and a Pfs25-Pfs28 multivalent protein vaccine in the Pichia pastoris protein expression system. These proteins were tested in mice using protein-in-adjuvant formulations and their immunogenicity was assessed. Pfs25-IMX313 nanoparticle induced significantly higher anti-Pfs25 antibodies than monomeric Pfs25 and the antibodies had higher avidity and transmission-blocking activity. All of the candidate vaccines generated, except for Pfs25-HBsAg VLP, were immunogenic. The Pfs25-IMX313 nanoparticle induced the highest antibody response in mice followed by the Pfs25-Pfs28 multivalent protein and Pfs25-Q&beta; VLP.