Targeting ribosome biogenesis and metabolism in acute myeloid leukaemia

Targeting ribosome biogenesis, a cellular process frequently upregulated in cancer, with the novel Pol I transcription inhibitor CX-5461 is highly efficacious in pre-clinical models of solid and haematological cancers, which lead to the commencement of clinical trials. However, as is common with single agent therapies in the mouse models (similar to challenges with treating human patients), the mice eventually succumb to disease, highlighting the need for a combination therapy approach. Based on the strong link between altered ribosome biogenesis and metabolism in cancer it was hypothesised that targeting these two processes in combination would prove efficacious in cancer, and acute myeloid leukaemia (AML) was chosen to test this as it is an aggressive malignancy with poor therapeutic options. In order to address this hypothesis In vitro drug synergy testing in AML cell lines was performed to identify promising combinations (Chapter 3), these were then tested for efficacy in in vivo transplant models of AML (Chapter 4). Finally, in vitro mechanistic analysis of the most promising drug combination was performed in order to understand the mechanisms of synergy (Chapter 5). In vitro testing of CX-5461 in combination with 10 clinically-approved metabolism-modifying drugs confirmed that orlistat, dichloroacetate (DCA), ritonavir, omeprazole and chloroquine act synergistically with CX-5461 to reduce cell viability in multiple AML cell lines. Three such combination therapies were evaluated in a syngeneic mouse AML model. Neither orlistat nor DCA improved survival in combination with CX-5461 compared to CX-5461 alone, however synergy was observed with the autophagy inhibitor chloroquine. Interestingly, the combination of CX-5461 and chloroquine had limited efficacy in human cell line xenograft mouse models, despite strong in vitro results. As the dosing of CX-5461 and chloroquine could not be increased due to toxicity, mechanistic analysis was performed in order to identify an alternative to chloroquine with reduced toxicity, and potentially improved efficacy. CX-5461 and chloroquine were found to synergise through cell cycle arrest and cell death in all four cell lines tested. Metabolic flux analysis revealed that the combination of drugs significantly affected mitochondrial activity, indicating that the combination of CX-5461 and chloroquine is placing the cells in mitochondrial stress. Therefore, direct targeting of the mitochondria was identified as a promising approach in combination with ribosome biogenesis inhibition with CX-5461, and various clinically-approved drugs that target mitochondria were identified for future combination testing

How the listener\u27s experience influences the rating of the intelligibility of hearing-impaired children\u27s speech

This paper discusses the importance of listener experience as a factor when developing intelligibility measures for hearing impaired children

Dr Jekyll, his new woman, and the late Victorian identity crisis

A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements for the degree of Doctor of PhilosophyI have written a novel as a prequel and parallel narrative to Robert Louis Stevenson’s The Strange Case of Dr. Jekyll and Mr. Hyde. The accompanying critical commentary draws on psychoanalytic and feminist perspectives, interpreted for “the complexities of fin‐de‐siècle British society” (Kucich, 2007, p.35), and examines my novel alongside other adaptations of Jekyll and Hyde. Although my work may invite comparisons with Neo‐Victorian novels such as works by Sarah Waters, Michael Cox’s The Meaning of Night (2006) or Michel Faber’s The Crimson Petal and the White (2002), I would argue that it has more in common with Jean Rhys’ Wide Sargasso Sea (1966) and Sophie Gee’s The Scandal of the Season (2008), both of which are prequels respectively to Jane Eyre and The Rape of the Lock. My research explores the potential origins of Jekyll’s decision to divide himself – the psychological roots of “his desire to reveal himself and his desire to conceal himself” (Laing, 1960, p.37). I have used this premise for both a psychoanalytic and a feminist perspective, drawing on the key works of Freud, specifically his writings on the unconscious and in relation to dreams, and Gilbert and Gubar’s seminal text The Madwoman in the Attic. The decision to use these texts as a framework was made using the rationale of two primary perspectives: Stevenson’s novel was inspired by a dream he had, which led me to Freud, whose theories fit so well with the manifestations of the Jekyll/Hyde personae, and whose analytic attention to sex and gender, with the argument that psychological and social forms of gender oppression cause a manufactured and oppressive role for women, is correlative with a feminist approach. Gilbert and Gubar’s critique analyses nineteenth century female writers, and it is my argument that Stevenson’s novel suggests that Jekyll’s rigid beliefs about his ‘other’ can be seen as both a resistance to the feminine within himself, and as an unconscious identification with women who felt suppressed in a patriarchal society and constrained by that society’s rigid gender expectations. This feature of late Victorian culture which Stevenson’s novel appears – on the surface ‐ to actively resist, is symbolised by the anonymous and one‐dimensional female characters within his novel, therefore this narrative motif is the starting point for my novel

Thermal Biology of Insect Immunity and Host-Microbe Interactions

The influence of temperature on interactions with pathogenic or symbiotic microbes is a driving force behind the survival of insects under climate change. However, we know little of how insects physiologically respond to these pressures. In temperate climates, winter dominates the thermal landscape; thus, I am particularly interested in how cold interacts with insect responses to microbes. Here I explore the thermal biology of the insect immune system and the impacts of cold on host-microbe interactions. First, I demonstrate that acute exposure to cold activates selective components of immunity in Drosophila melanogaster, as a compensatory response to trade-offs or injury. Next, I show that cold acclimation decreases immune function at low temperatures in Gryllus veletis at the same time that cold tolerance increases. I conclude that this is a trade-off between immunity and the response to cold. Third, I demonstrate that immune activity varies seasonally in insects, but that each species responds differently. These shifts were likely driven by species-specific responses to multiple overwintering pressures. Fourth, I demonstrate that thermal plasticity in both Gryllus veletis and the fungal pathogen Metarhizium brunneum contribute to the outcome of infection. Further, fluctuating temperatures produce different outcomes of infection than constant temperatures, but we can predict these outcomes based on additive thermal performance under constant conditions. Lastly, I observe that the composition of the hindgut microbiome in Gryllus veletis, containing both beneficial and pathogenic microbes, shifts irreversibly across seasons. Further, microbial shifts coincide with changes in both cold tolerance and immune activity, which indicate that there is a functional relationship between the microbiome and host survival of low temperatures. Overall, changes in temperature are inextricably linked to changes in insect responses to both pathogenic and symbiotic microbes, which has likely selected for an adaptive physiological connection between insect immunity and the response to cold. I demonstrate that the connection between physiological responses to abiotic and biotic pressures modify our interpretation of phenotype. Therefore, we cannot rely on a univariate and species-isolated understanding of how insects respond to temperature if we are to predict the impact of climate change on their fitness

Kicking the Vietnam syndrome? Collective memory of the Vietnam War in fictional American cinema following the 1991 Gulf War

This thesis analyses the concept of the “Vietnam Syndrome” and its continuing manifestation in fictional American films produced after the 1991 Gulf War, with reference to depictions of the Vietnam, Gulf and Iraq Wars. Based on contemporary press reports as source material and critical analysis, it identifies the “Vietnam Syndrome” as a flexible and altering national psychological issue characterised initially as a simple aversion to military engagement, but which grew to include collective feelings of shame, guilt and a desire to rewrite history. The thesis argues that the “Syndrome” was not quashed by the victory of the Gulf War in 1991, as had been speculated at the time. Rather, the thesis argues that it was only temporarily displaced and continues to be an ingrained feature of the collective American psyche in current times. The argument is based on theories of collective memory, according to which social attitudes are expressed in cultural products such as films. The relationships between memory and history, and between memory and national identity are explored as two highly relevant branches of collective memory research. The first of these combines the theories of Bodnar (1992), Sturken (1997), Winter and Sivan (1999) and Wertsch (2002), among others, to define memory’s relationship with history and position in the present. The discussion of the relationship between memory and national identity describes the process by which memory is adopted into the national collective, based on the research of Schudson (1992) and Hall (1999). Consideration is given to the alternative theories of Comolli and Narboni (1992 [1969]), Hobsbawm and Ranger (1983) and Miller (2005) that propose a unified representation from a dominant ideology and of The Popular Memory Group (1982) who argue a counter-hegemonic popular memory. The thesis argues that both are insufficient to account for public memory, establishing a multi-sourced collective memory as the basis for its arguments, as described by Hynes (1999) and Wertsch (2002). Successive chapters provide a close analysis of films in relation to the “Vietnam Syndrome”. Each of the films shows the different approaches to the conflicts and ways the “Vietnam Syndrome” manifests itself. Chapter 3 provides a summary of Vietnam War films released prior to the main period focused upon in this thesis, in order to contextualise the post-Gulf War texts. Chapter 4 analyses Heaven and Earth (1993, Dir. Oliver Stone) as a revolutionary depiction of the Vietnam War from a Vietnamese depiction. Chapter 5 discusses The War (1994, Dir. Jon Avnet) as a late revisionist text. The focus of Chapter 6 is Apocalypse Now Redux (2001, Dir. Francis Ford Coppola), a revision of a vision, in which the additional scenes are analysed for their contribution to this later, more reflective version of the 1970s text Apocalypse Now. The last Vietnam film analysed, We Were Soldiers (2002, Dir. Randall Wallace), is the subject of Chapter 7 and is discussed with reference to post-September 11 American society and the dormant period of the “Vietnam Syndrome.” Chapter 8 brings the previous Vietnam War film analysis chapters together to form intermediate conclusions prior to the progression to Gulf War films. Chapter 9 provides a break in the film analysis chapters to consider the press coverage of the Gulf War, compared to that of Vietnam, paving the way for the following discussion of Gulf War films. Press coverage of the Gulf War influences the visual depiction of the Gulf War in both Three Kings (1999, Dir. David O’Russell) in Chapter 10 and Jarhead (2005, Dir. Sam Mendes) in Chapter 11. The reading of Three Kings also analyses the narrative as a metaphor for American concerns over the American-led coalition’s conduct during the conflict, while Chapter 11 argues the use of Vietnam War films as media templates (Kitzinger, 2000) in Jarhead. Finally, Chapter 13 brings the film analysis to a close by discussing the early representations of the Iraq War that have emerged in recent years, including: American Soldiers: A Day in Iraq (2005, Dir. Sidney J. Furie), Home of The Brave (2006, Dir. Irwin Winkler), Stop-Loss (2008, Dir. Kimberley Peirce), Lions For Lambs (2007, Dir. Robert Redford) Redacted (2008, Dir. Brian de Palma) and The Hurt Locker (2008, Dir. Kathryn Bigelow). The main, but not exclusive, features typifying the “Vietnam Syndrome” expressed through the films include: a reluctance to engage in or support foreign military intervention; use of “good war” and “bad war” discourse; signs of a collective national trauma of defeat; expressions of guilt for the consequences of American actions and failings of policy; attempts to restore the national self-image. This thesis concludes that the “Vietnam Syndrome” is still relevant to American society and that it is expressed through films in a variety of ways. It argues that the Vietnam War and the “Vietnam Syndrome” have become frames of reference for the discussion and representation of conflict and that the American collective psyche suffers a mixture of syndromes, some mutually enforcing and some contradictory, that are triggered by a variety of circumstances. The “Vietnam Syndrome” is identified as the most prolific of these and through its construction and circulation in media products, including cinema, this thesis argues it has become an umbrella term for the remnants of angst over Vietnam and new concerns over other conflicts

Studies on preconditioning with adenosine, glutamate and ouabain in rat hippocampal slices

Preconditioning is the phenomenon whereby tolerance to lethal insults is induced by exposing the tissue to a prior sublethal stimulus. This exists in several forms, such as ischaemic preconditioning, adenosine preconditioning and excitotoxic preconditioning. Adenosine preconditioning is known to be mediated by activation of A1 receptors and ATP-sensitive potassium channels whilst excitotoxic preconditioning mainly involves stimulation of NMDA receptors, nitric oxide and most likely ATP-sensitive potassium channel activation. ATP-sensitive potassium channel openers such as pinacidil and diazoxide are also known to exert preconditioning against various types of insults. There have been several models of ischaemia used to study preconditioning in vivo and in vitro leading to some confusion over the effects of preconditioning agents. High concentrations of glutamate or NMDA have been used as models of excitotoxicity in many experimental paradigms. Some molecular changes are associated with preconditioning phenomena, the most prominent being an increased expression of heat shock protein 72 (HSP72). The aims of the current study were to: 1) investigate the effects of exogenous glutamate and other depolarizing agents in the slice preparation and their validity for use as toxic agents 2) examine any potential preconditioning neuroprotection induced by adenosine against various depolarizing agents and elucidate the underlying mechanisms where relevant 3) examine the excitotoxic preconditioning phenomenon and possible underlying mechanisms 4) look at the effectiveness of other known preconditioning agents e.g. ATP-sensitive potassium channel openers against depolarizing agents and identify the underlying mechanisms of protection 5) identify any molecular changes that may occur during acute models of chemical ischemia or acute preconditioning. The rat hippocampal slice preparation was used to investigate the effects of depolarizing agents and preconditioning paradigms upon the extracellularly evoked field epsps, orthodromic and antidromic population spikes. Western blotting was used to detect any changes in the levels of HSP72 in the slices that may have occurred as a result of the depolarizing agents or the preconditioning treatments. It was first established that 5mM and 10mM glutamate induced depressions in the amplitudes of orthodromic population spikes which recovered to a stable plateau. The degree of recovery of the spikes depended partially upon the initial size of the response. As adenosine is known to be released in response to glutamate receptor stimulation, the effects of 5mM glutamate upon the orthodromic spikes were studied in the presence of the A1 receptor antagonist, DPCPX. It was observed that DPCPX did not attenuate the depression of the response during glutamate perfusion but there was a significant elevation in the post-glutamate recovery of the response. This effect was not observed when the protocol was applied to antidromic population spikes and field epsps, both of which showed a depression in response during 5mM glutamate perfusion but recovered fully when glutamate was removed. The field epsps showed a trend whereby smaller epsps recovered to a far greater degree than population spikes. Although this effect was not significant, the NMDA receptor blocker, MK-801, was co-perfused with glutamate during epsp recordings to examine this further. The degree to which MK-801 alone affected the response correlated with the post-glutamate recovery. To study this effect, isolated NMDA-receptor mediated epsps were recorded and the effects of 5mM glutamate upon them were studied. There was a similar tendency for small NMDA-receptor mediated epsps to recover to a higher level following glutamate treatment compared with larger potentials. In the presence of DPCPX, the larger potentials showed a significant elevation in recovery following treatment with glutamate. It was also shown that the post-5mM glutamate recovery of the orthodromic population spikes was elevated by the presence of the A2a receptor antagonist, SCH 58261. Further experiments using the ATP-sensitive potassium channel blocker, glibenclamide, indicated that this effect may be due to increasing the opening of these channels. Adenosine preconditioning was attempted using 10mM glutamate as an insult. It was shown that adenosine could not precondition against this effect in antidromic or orthodromic population spikes. The effects of the sodium-potassium ATPase inhibitor, ouabain, upon the evoked responses were studied as an alternative insult. It was shown that ouabain induced depressions in field epsps, orthodromic and antidromic population spikes. The antidromic population spikes showed significantly smaller depressions than the orthodromic responses. Further experiments using the glutamate receptor antagonist, kynurenic acid, showed that glutamate receptors mediated the effects of ouabain upon the orthodromic population spikes but not the antidromic spikes. Adenosine preconditioning was attempted against ouabain. It was shown that adenosine preconditioned against the effects of ouabain upon orthodromic and antidromic population spikes but not field epsps. Further experiments were conducted using antidromic population spikes. It was shown using various antagonists, that adenosine protection against ouabain was mediated by A1 receptors, ATP-sensitive potassium channels, NMDA receptors and nitric oxide. To extend these results further, preconditioning using the ATP-sensitive potassium channel opener, pinacidil, was attempted against 10mM glutamate and ouabain. It was shown that pinacidil was able to precondition the antidromic population spike against either insult. Using the NMDA receptor antagonist, DL-AP5, showed that the preconditioning effect of pinacidil against ouabain was mediated by NMDA receptors. Another preconditioning paradigm was attempted to see if glutamate could precondition against ouabain. It was shown that pre- treatment with glutamate resulted in enhancing the depressant effect of ouabain upon field epsps and antidromic population spikes. To further examine the effects of ouabain upon antidromic population spikes, ouabain was co-perfused in the presence of the intracellular calcium chelator, BAPTA-AM. This resulted in enhancing the depressant effect of ouabain upon the response. A similar result was observed when the calcium concentration in the perfusion medium was lowered to 0.5mM from 2.5mM whereas increasing the concentration to 5mM attenuated the depressant effect. Ouabain was also co-perfused in the presence of charybdotoxin, a blocker of large-conductance calcium activated potassium channels. It was observed that charybdotoxin enhanced the effect of ouabain upon the antidromic spikes. No changes were detected in HSP72 expression in the slices in response to ouabain treatment, 10mM glutamate treatment, pinacidil preconditioning treatment or glutamate preconditioning. The present results show that glutamate and ouabain can induce depressions in the evoked responses from the rat hippocampal slice and that the effects of 5mM glutamate can be attenuated by adenosine receptor antagonists. In addition, adenosine can precondition against ouabain but not glutamate and this effect involves A1 receptors, NMDA receptors, nitric oxide and ATP-sensitive potassium channels. It has also been observed that pinacidil can precondition against ouabain or glutamate and NMDA receptors may be involved in this effect. The inability of glutamate to precondition against ouabain in evoked responses was also demonstrated. The study highlights the effectiveness of preconditioning agents against different depolarizing agents and the interactions between adenosine and glutamate receptors which play a role in preconditioning

Cyberpolicing in Canada: A Scoping Review

A recent stream of government efforts have surfaced in an attempt to tackle cybercrime in Canada and improve law enforcement responses to cybercrime, such as funding, actionable intelligence, and the creation of new policing response units. However, we know little of ‘what works’ with respect to cyberpolicing, meaning that these endeavours, and policymakers and funding organizations, are operating without such insights. Therefore, this study sought to conduct an evidence assessment into research on cybercrime-related topics through a scoping review. Our findings show that the overall volume of Canadian cyberpolicing literature is low, and many important subjects are entirely lacking in research. Additionally, we found a distinct shortage of independent or rigorous evaluation of cyberpolicing strategies. From these findings, we offer a range of critical recommendations to improve the state of Canadian research on cyberpolicing

What Do We Know About Senior Citizens As Cybervictims? A Rapid Evidence Synthesis

Internet-based victimization of senior citizens is an important potential threat of growing social, economic, and public policy interest. Given this, we sought to examine whether the existing research base could be used to formulate sound public policy in this area. To do so, we conducted a rapid evidence synthesis and assessment of the research literature from 2010-2020 surrounding three central organizing themes: cyber-related harms, responses and strategies, and prevention programs and solutions. Results reveal that there is an insufficient research base, lack of diverse research topics, and shortage of research beyond that of which is exploratory in nature. However, our findings did show promising insights on areas for future research development, such as support for seniors and their caregivers. We conclude with recommendations for future research that can begin to address the vulnerabilities senior citizens face with online victimization and potential policy implications for how to effectively combat this issue and these acts

Another Digital Divide: Cybersecurity in Indigenous Communities

The Indigenous ‘digital divide’ relates to community-level disparities in access and use of online technologies, a prominent public policy issue that federal governments have attempted to address. Following from such efforts is an expected increase in communication and other technologies. However, concurrently, cybersecurity becomes a matter warranting consideration, as increased access means increased exposure to online harms for which many Indigenous communities may lack awareness, education, and prevention skills. To offer key insights relevant to this matter, this study conducted a systematic review of research pertaining to Indigeneity and cybersecurity issues. Findings show that critical subject areas, such as human trafficking and cyberbullying, are starkly under-researched and small in study volume. It was also discovered that there is very little diversity in research topics, rendering the research base narrow in scope. From these findings, this study concludes with several critical areas for future research and evaluation, as is necessary for public policy and prevention-oriented initiatives

Introduction: Language Sustainability in the Circumpolar North

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