Browsing Pharmacy - Doctoral Theses by Issue Date
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- ItemParacetamol metabolism in postoperative patients(University College Cork, 2012-01) Murphy, Philip Gerard MacHale; Kennedy, Julia M.; Byrne, Stephen; Creaton, GeraldineIntroduction: Despite being available for more than 50 years, there is still much to learn about paracetamol. Postoperative analgesic regimens that maintain good pain control while minimising exposure to opiates are beneficial and paracetamol has had a resurgence in this role since an IV formulation came to market. However there is evidence to suggest currently licensed doses are sub-therapeutic, especially when administered orally or rectally. Higher, unlicensed doses are now being advocated but, prior to this study, there was little evidence of their safety in surgical patients. When assessing drug safety in surgical patients a number of surgery and patient related factors influence results, and these must be considered. Methods: Major and intermediate surgical patients were recruited from two hospitals in Ireland. They were administered IV paracetamol at either 9g or 4g daily doses. In addition they received daily sub therapeutic doses of four other medicines to indicate the activity of their CYP450 enzymes that are involved in paracetamol metabolism. Urine and blood samples were collected to determine paracetamol pharmacokinetics, CYP450 activity, inflammatory cytokine concentration and for evidence of hepatotoxicity. Results: There were 33 patients that participated in the study. There was no evidence of clinically significant hepatotoxicity occurring in any patient during the study period, but there could have been changes following this time. Paracetamol disposition was shown to change, however half-life remained relatively constant. There were a number of changes to the way paracetamol was metabolised following surgery that maintained this rate of elimination. Conclusion: Doses of up to 9g per day given to major surgical patients for up to five days postoperatively produced no evidence of hepatotoxicity. Further research is warranted to determine the clinical utility of these higher doses
- ItemNovel insights into the role of the GABAB receptor in depression and anxiety(University College Cork, 2013) Felice, Daniela; Cryan, John F.; O'Leary, Olivia; European CommissionThe GABAB receptor is a functional heterodimer comprising the GABAB1 and GABAB2 subunits, with the GABAB1 subunit displaying two major isoforms, GABAB(1a) and GABAB(1b). Preclinical findings have strongly implicated the GABAB receptor in stress-related psychiatric disorders, however, the precise contribution of the GABAB receptor in depression and anxiety disorders remains unknown. Emerging data suggest that the interaction between adverse environmental conditions, such as early life stress, and a specific genetic composition can increase the risk to develop psychiatric disorders in adulthood. This thesis investigated the role of the GABAB receptor alone or in combination with early-life stress (maternal separation), in modulating antidepressant like and anxiety-related behaviours. Pharmacological blockade of the GABAB receptor with CGP52432 had antidepressant-like behavioural effects. Moreover, mice lacking the GABAB(1b) receptor subunit isoform exhibited antidepressant-like behaviours in adulthood but anxiety-like behaviour in early-life. In response to maternal separation, GABAB(1a)-/- mice exhibited early-life stress-induced anhedonia, a core symptom of depression, while GABAB(1b)-/- mice exhibited a more resilient phenotype. Moreover, when compared with wildtype or GABAB(1a)-/- mice, GABAB(1b)-/- mice that underwent maternal separation exhibited enhanced stressinduced neuronal activation in the hippocampus and in the nucleus accumbens (NAcc), a critical area for anhedonia thus suggesting that enhanced stress-induced neuronal activation in the hippocampus and NAcc in GABAB(1b)-/- mice may be important for their antidepressant-like phenotype and their resilience to stress-induced anhedonia. Pharmacological blockade of GABAB receptor and GABAB(1b) receptor subunit isoform loss of function increased adult hippocampal cell proliferation, thus suggesting that increased hippocampal neurogenesis could be a potential mechanism for the antidepressant-like effects of GABAB receptor antagonists and GABAB(1b) receptor subunit isoform disruption. Finally, this thesis investigated whether the expression of several genes involved in hippocampal neurogenesis or the antidepressant response were altered in the mouse hippocampus following chronic treatment with a GABAB receptor antagonist.
- ItemNovel roles for the GABAB receptor in anxiety and cocaine addiction(University College Cork, 2013) Sweeney, Fabian; Cryan, John F.; European CommissionThe GABAB receptor has been postulated as a possible drug target in the treatment of anxiety disorders and cocaine addiction. Indeed, a wealth of preclinical data is emerging that has shown that mice lacking functional GABAB receptors display a highly anxious behaviour across a range of behavioural models of anxiety. Additionally, novel compounds that act by altering the allosteric conformation of the GABAB receptor to a more active state; the GABAB receptor positive modulators, have been repeatedly demonstrated to have anxiolytic effects in animals. In addition to being a putative anxiolytic drug target, the GABAB receptor has been identified as a novel target for antiaddictive therapies. Indeed GABAB receptor positive modulators have been demonstrated to have anti-addictive properties across a broad variety of behavioural paradigms. Despite these findings, several gaps in our knowledge of the role played by the GABAB receptor in both anxiety and drug abuse disorder exist. The aim of this thesis was to use preclinical animal models in an effort to further probe the role played by the GABAB receptor in anxiety and addiction. Our studies initially examined the role played by the GABAB receptor in the neurodevelopmental processes underpinning of anxiety. Our studies demonstrated that treating mouse pups in early life with the GABAB receptor agonist baclofen produced an anxious phenotype in adult life, whereas treatment with the GABAB receptor antagonist CGP52432 produced no effects on adult behaviour. Further to this, we examined whether the anxious behaviour induced by early life blockade of the serotonin reuptake transporter was dependant on alterations in GABAB receptor function. Our studies however revealed no effect of early life selective serotonin reuptake inhibitor treatment on adult life baclofen sensitivity. The next issue addressed in this thesis is the characterization of the effects of a GABAB receptor positive modulator and a GABAB receptor antagonist in a behavioural model of conditioned fear behaviour. These novel classes of GABAB receptor ligands have been considerably less well characterized in this facet of preclinical anxiety behaviour than in terms of innate anxiety behaviour. Our study however revealed that the GABAB receptor positive modulator GS39783 and the GABAB receptor antagonist CGP52432 were without effect on the acquisition, expression or extinction of conditioned fear in our model. The next element of this thesis dealt with the characterization of a novel mouse model, the GABAB(2)- S892A mouse. This mouse has been engineered to express a form of the GABAB(2) receptor subunit wherein the function determining serine phosphorylation site cannot be phosphorylated. We initially tested this mouse in terms of its GABAB receptor function in adult life, followed by testing it in a battery of tests of unconditioned and learned anxiety behaviour. We also examined the behavioural and molecular responses of the GABAB(2)-S892A mouse to cocaine. All of our studies appear to show that the GABAB(2)-S892A mouse is indistinguishable from wildtype controls. The final aim of the thesis was to investigate the behavioural and molecular sensitivity of the GABAB(1) subunit isoform null mice, the GABAB(1a) -/- and GABAB(1b) -/- mice to cocaine. Our studies revealed that these mice display differing behavioural responses to cocaine, with the GABAB(1a) -/- mouse displaying a hypersensitivity to the acute locomotor effects of cocaine, while the GABAB(1b) -/- displayed blunted locomotor sensitisation to cocaine.
- ItemThe gut microbiota as a contributing factor to antipsychotic-induced weight gain and metabolic dysfunction(University College Cork, 2013) Davey, Kieran; O'Mahony, Siobhain M.; Dinan, Timothy G.; Cryan, John F.Schizophrenia represents one of the world’s most devastating illnesses due to its often lifelong course and debilitating nature. The treatment of schizophrenia has vastly improved over recent decades with the discovery of several antipsychotic compounds; however these drugs are not without adverse effects that must be addressed to maximize their therapeutic value. Newer, atypical, antipsychotics are associated with a compilation of serious metabolic side effects including weight gain, insulin resistance, fat deposition, glucose dysregulation and ensuing co-morbidities such as type II diabetes mellitus. The mechanisms underlying these side effects remain to be fully elucidated and adequate interventions are lacking. Further understanding of the factors that contribute these side effects is therefore required in order to develop effective adjunctive therapies and to potentially design antipsychotic drugs in the future with reduced impact on the metabolic health of patients. We investigated if the gut microbiota represented a novel mechanism contributing to the metabolic dysfunction associated with atypical antipsychotics. The gut microbiota comprises the bacteria that exist symbiotically within the gastrointestinal tract, and has been shown in recent years to be involved in several aspects of energy balance and metabolism. We have demonstrated that administration of certain antipsychotics in the rat results in an altered microbiota profile and, moreover, that the microbiota is required for the full scale of metabolic dysfunction to occur. We have further shown that specific antibiotics can attenuate certain aspects of olanzapine and risperidone–induced metabolic dysfunction, in particular fat deposition and adipose tissue inflammation. Mechanisms underlying this novel link appear to involve energy utilization via expression of lipogenic genes as well as reduced inflammatory tone. Taken together, these data indicate that the gut microbiota is an important factor involved in the myriad of metabolic complications associated with antipsychotic therapy. Furthermore, these data support the future investigation of microbial-based therapeutics for not only antipsychotic-induced weight gain but also for tackling the global obesity epidemic.
- ItemP-glycoprotein inhibition as a strategy to increase drug delivery across the blood-brain barrier: focus on antidepressants(University College Cork, 2013) O'Brien, Fionn E.; Cryan, John F.; Griffin, Brendan T.Depression is among the leading causes of disability worldwide. Currently available antidepressant drugs have unsatisfactory efficacy, with up to 60% of depressed patients failing to respond adequately to treatment. Emerging evidence has highlighted a potential role for the efflux transporter P-glycoprotein (P-gp), expressed at the blood-brain barrier (BBB), in the aetiology of treatment-resistant depression. In this thesis, the potential of P-gp inhibition as a strategy to enhance the brain distribution and pharmacodynamic effects of antidepressant drugs was investigated. Pharmacokinetic studies demonstrated that administration of the P-gp inhibitors verapamil or cyclosporin A (CsA) enhanced the BBB transport of the antidepressants imipramine and escitalopram in vivo. Furthermore, both imipramine and escitalopram were identified as transported substrates of human P-gp in vitro. Contrastingly, human P-gp exerted no effect on the transport of four other antidepressants (amitriptyline, duloxetine, fluoxetine and mirtazapine) in vitro. Pharmacodynamic studies revealed that pre-treatment with verapamil augmented the behavioural effects of escitalopram in the tail suspension test (TST) of antidepressant-like activity in mice. Moreover, pre-treatment with CsA exacerbated the behavioural manifestation of an escitalopram-induced mouse model of serotonin syndrome, a serious adverse reaction associated with serotonergic drugs. This finding highlights the potential for unwanted side-effects which may occur due to increasing brain levels of antidepressants by P-gp inhibition, although further studies are needed to fully elucidate the mechanism(s) at play. Taken together, the research outlined in this thesis indicates that P-gp may restrict brain concentrations of escitalopram and imipramine in patients. Moreover, we show that increasing the brain distribution of an antidepressant by P-gp inhibition can result in an augmentation of antidepressant-like activity in vivo. These findings raise the possibility that P-gp inhibition may represent a potentially beneficial strategy to augment antidepressant treatment in clinical practice. Further studies are now warranted to evaluate the safety and efficacy of this approach.
- ItemNovel coatings for hard tissue implants(University College Cork, 2013) O'Sullivan, Caroline; Crean, Abina M.; Ryan, Katie B.A novel deposition process named CoBlastTM, based on grit blasting technology, has been used to deposit hydroxyapatite (HA) onto titanium (Ti) metal using a dopant/abrasive regime. The various powders (HA powder, apatitic abrasives) and the treated substrates were characterised for chemical composition, coating coverage, crystallinity and topography including surface roughness. The surface roughness of the HA surfaces could be altered using apatitic abrasives of different particle sizes. Compared to the standard plasma spraying process, the CoBlast surface produced excellent coating adhesion, lower dissolution, higher levels of mechanical and chemical stability in stimulated body fluid (SBF). Enhanced viability of osteoblastic cells was also observed on the CoBlast HA surfaces compared to the microblast and untreated Ti as well as the plasma HA coating. CoBlast offers an alternative to the traditional methods of coating HA implants with added versatility. Apatites substituted with antimicrobial metals can also be deposited to add functionality to HA coatings without cytotoxicty. The potential use of these coatings as an infection preventing strategy for application on hard tissue implants was assessed in vitro and also in vivo. Surface physicochemical properties and morphology were determined in addition to surface cytocompatibility assessments using a MG-63 osteoblast cell line. The antibacterial potential of the immobilised metal ion on the surface and the eluted ion to a lesser extent, contributed to the anticolonising behaviour of the surfaces against a standard bacteria strain (S. aureus) as well as a number of clinically relevant strains (MRSA, MSSA and S. epidermis). The results revealed that the surfaces coated with silver substituted apatites (AgA) outperformed the other apatites examined (apatites loaded with Zn, Sr and both Ag and Sr ions). Assessment of bacterial adherence on coated K-wires following subcutaneous implantation in a nude mouse infection model (S. aureus) for two days demonstrated that the 12% wt surface outperformed the 5% wt AgA coating. Lower inflammatory responses were activated with the insertion of the Ag loaded K-wires with a localised infection at the implantation site noted over the two day study period. These results indicated that the AgA coating on the surface of orthopaedic implants demonstrate good biocompatibility whilst inhibiting bacterial adhesion and colonising of the implant surface.
- ItemSubstance misuse in young people in Ireland - a focus on benzodiazepines(University College Cork, 2014) Murphy, Kevin D.; Byrne, Stephen; Sahm, Laura J.; McCarthy, SuzanneBenzodiazepines are a class of drugs that are prescribed for the treatment of anxiety and insomnia. Due to the powerful tolerance that can develop as a result of sustained use, benzodiazepines can also be dependence-forming. Benzodiazepine dependence can occur from prescribed and from recreational use, and is a significant issue for young people. The consequences of benzodiazepine dependence include cognitive and learning impairment, depressive symptoms, and increased suicide risk. Despite these risks, the nature of youth benzodiazepine use has not been explored to the same extent as other drugs. A review of existing Irish literature revealed that benzodiazepines are one of the five most recreationally-used drugs among young people. Analyses of young people attending a treatment centre indicated that young attendees from urban areas were more likely to be referred to the centre because of benzodiazepines than rural attendees. Further examination of the centre’s attendees showed that regular benzodiazepine users experienced more paranoia, loss of interest in sport, and pallor than non-regular users. Analysis of benzodiazepine prescribing to young people revealed that approximately one in seven young people were prescribed benzodiazepines for periods greater than recommended by national guidelines. Young benzodiazepine users discussed in interviews that they took benzodiazepines to escape from negative feelings and that they are generally taken in a social setting. Further interviews with youth counsellors and general practitioners highlighted that both family and community attitude to benzodiazepine use can impact on a young person’s benzodiazepine usage. Suggestions for reducing benzodiazepine use such as psychological alternatives to medication, public awareness campaigns and prescribing restrictions are provided. Future research can elaborate upon this work to determine other methods of reducing youth benzodiazepine use and the damage that it causes to the young people themselves, but also to their families, their community, and society at large.
- ItemDesign and evaluation of novel microencapsulation technologies to enhance delivery of Ciclosporin(University College Cork, 2014) Keohane, Kieran; Griffin, Brendan T.; Science Foundation IrelandDrug delivery systems influence the various processes of release, absorption, distribution and elimination of drug. Conventional delivery methods administer drug through the mouth, the skin, transmucosal areas, inhalation or injection. However, one of the current challenges is the lack of effective and targeted oral drug administration. Development of sophisticated strategies, such as micro- and nanotechnology that can integrate the design and synthesis of drug delivery systems in a one-step, scalable process is fundamental in advancing the limitations of conventional processing techniques. Thus, the objective of this thesis is to evaluate novel microencapsulation technologies in the production of size-specific and target-specific drug-loaded particles. The first part of this thesis describes the utility of PDMS and silicon microfluidic flow focusing devices (MFFDs) to produce PLGA-based microparticles. The formation of uniform droplets was dependent on the surface of PDMS remaining hydrophilic. However, the durability of PDMS was limited to no more than 1 hour before wetting of the microchannel walls with dichloromethane and subsequent swelling occurred. Critically, silicon MFFDs revealed very good solvent compatibility and was sufficiently robust to withstand elevated fluid flow rates. Silicon MFFDs facilitated experiments to run over days with continuous use and re-use of the device with a narrower microparticle size distribution, relative to conventional production techniques. The second part of this thesis demonstrates an alternative microencapsulation technology, SmPill® minispheres, to target CsA delivery to the colon. Characterisation of CsA release in vitro and in vivo was performed. By modulating the ethylcellulose:pectin coating thickness, release of CsA in-vivo was more effectively controlled compared to current commercial CsA formulations and demonstrated a linear in-vitro in-vivo relationship. Coated minispheres were shown to limit CsA release in the upper small intestine and enhance localised CsA delivery to the colon.
- ItemApplication of mesoporous silica for the oral delivery of poorly water-soluble drugs(University College Cork, 2014) Ahern, Robert J.; Crean, Abina M.; Ryan, Katie B.; Science Foundation IrelandThe objective of this thesis was to improve the dissolution rate of the poorly waters-soluble drug, fenofibrate by processing it with a high surface area carrier, mesoporous silica. The subsequent properties of the drug – silica composite were studied in terms of drug distribution within the silica matrix, solid state and release properties. Prior to commencing any experimental work, the properties of unprocessed mesoporous silica and fenofibrate were characterised (chapter 3), this allowed for comparison with the processed samples studied in later chapters. Fenofibrate was a highly stable, crystalline drug that did not adsorb moisture, even under long term accelerated storage conditions. It maintained its crystallinity even after SC-CO2 processing. Its dissolution rate was limited and dependent on the characteristics of the particular in vitro media studied. Mesoporous silica had a large surface area and mesopore volume and readily picked up moisture when stored under long term accelerated storage conditions (75% RH, 40 oC). It maintained its mesopore character after SC-CO2 processing. A variety of methods were employed to process fenofibrate with mesoporous silica including physical mixing, melt method, solvent impregnation and novel methods such as liquid and supercritical carbon dioxide (SC-CO2) (chapter 4). It was found that it was important to break down the fenofibrate particulate structure to a molecular state to enable drug molecules enter into the silica mesopores. While all processing methods led to some increase in fenofibrate release properties; the impregnation, liquid and SC-CO2 methods produced the most rapid release rates. SC-CO2 processing was further studied with a view to optimising the processing parameters to achieve the highest drug-loading efficiency possible (chapter 5). In this thesis, it was that SC-CO2 processing pressure had a bearing on drug-loading efficiency. Neither pressure, duration or depressurisation rate affected drug solid state or release properties. The amount of drug that could be loaded onto to the mesoporous silica successfully was also investigated at different ratios of drug mass to silica surface area under constant SC-CO2 conditions; as the drug – silica ratio increased, the drug-loading efficiency decreased, while there was no effect on drug solid state or release properties. The influence of the number of drug-loading steps was investigated (chapter 6) with a view to increasing the drug-loading efficiency. This multiple step approach did not yield an increase in drug-loading efficiency compared to the single step approach. It was also an objective in this chapter to understand how much drug could be loaded into silica mesopores; a method based on the known volume of the mesopores and true density of drug was investigated. However, this approach led to serious repercussions in terms of the subsequent solid state nature of the drug and its release performance; there was significant drug crystallinity and reduced release extent. The impact of in vitro release media on fenofibrate release was also studied (chapter 6). Here it was seen that media containing HCl led to reduced drug release over time compared to equivalent media not containing HCl. The key findings of this thesis are discussed in chapter 7 and included: 1. Drug – silica processing method strongly influenced drug distribution within the silica matrix, drug solid state and release. 2. The silica surface area and mesopore volume also influenced how much drug could be loaded. It was shown that SC-CO2 processing variables such as processing pressure (13.79 – 41.37 MPa), duration time (4 – 24 h) and depressurisation rate (rapid or controlled) did not influence the drug distribution within the SBA- 15 matrix, drug solid state form or release. Possible avenues of research to be considered going forward include the development and application of high resolution imaging techniques to visualise drug molecules within the silica mesopores. Also, the issues surrounding SBA-15 usage in a pharmaceutical manufacturing environment should be addressed.
- ItemPharmacotherapy optimization in older patients by a structured clinical pharmacist assessment and intervention(University College Cork, 2014) O'Sullivan, David.; Byrne, Stephen; O'Mahony, Denis; Health Research Board; Centre for Ageing Research and Development in IrelandIntroduction: Older individuals are particularly vulnerable to potentially inappropriate prescribing (PIP), drug related problems (DRPs) and adverse drug reactions (ADRs). A number of different interventions have been proposed to address these issues. However to-date there is a paucity of well-designed trials examining the impact of such interventions. Therefore the aims of this work were to: (i) establish a baseline PIP prevalence both nationally and internationally using the STOPP, Beers and PRISCUS criteria, (ii) identify the most comprehensive method of assessing PIP in older individuals, (iii) develop a structured pharmacist intervention supported by a computer decisions support system (CDSS) and (iv) examine the impact of this intervention on prescribing and incidence of ADRs. Results: This work identified high rates of PIP across all three healthcare settings in Ireland, 84.7% in the long term care, 70.7% in secondary care and 43.3% in primary care being reported. This work identified that for a comprehensive assessment of prescribing to be undertaken, an amalgamation of all three criteria should be deployed simultaneously. High prevalences of DRPs and PIP in older hospitalised individuals were identified. With 82.0% and 76.3% of patients reported to have at least one DRP or PIP instance respectively. The structured pharmacist intervention demonstrated a positive impact on prescribing, with a significant reduction MAI scores being reported. It also resulted in the intervention patients’ having a reduced risk of experiencing an ADR when compared to the control patients (absolute risk reduction of 6.8 (95% CI 1.5% - 12.3%)) and the number needed to treat = 15 (95% CI 8 - 68). However the intervention was found to have no significant effect on length of stay or mortality rate. Conclusion: This work shows that PIP is highly prevalent in older individuals across three healthcare settings in Ireland. This work also demonstrates that a structured pharmacist intervention support by a dedicated CDSS can significantly improve the appropriateness of prescribing and reduce the incidence of ADRs in older acutely ill hospitalised individuals.
- ItemModified cyclodextrins as novel non-viral vectors for neuronal siRNA delivery: focus on Huntington’s disease(University College Cork, 2014) Godinho, Bruno M. D. C.; O'Driscoll, Caitríona M.; Cryan, John F.; Science Foundation Ireland; Irish Drug Delivery NetworkHuntington’s Disease (HD) is a rare autosomal dominant neurodegenerative disease caused by the expression of a mutant Huntingtin (muHTT) protein. Therefore, preventing the expression of muHTT by harnessing the specificity of the RNA interference (RNAi) pathway is a key research avenue for developing novel therapies for HD. However, the biggest caveat in the RNAi approach is the delivery of short interfering RNA (siRNAs) to neurons, which are notoriously difficult to transfect. Indeed, despite the great advances in the field of nanotechnology, there remains a great need to develop more effective and less toxic carriers for siRNA delivery to the Central Nervous System (CNS). Thus, the aim of this thesis was to investigate the utility of modified amphiphilic β-cyclodextrins (CDs), oligosaccharide-based molecules, as non-viral vectors for siRNA delivery for HD. Modified CDs were able to bind and complex siRNAs forming nanoparticles capable of delivering siRNAs to ST14A-HTT120Q cells and to human HD fibroblasts, and reducing the expression of the HTT gene in these in vitro models of HD. Moreover, direct administration of CD.siRNA nanoparticles into the R6/2 mouse brain resulted in significant HTT gene expression knockdown and selective alleviation of rotarod motor deficits in this mouse model of HD. In contrast to widely used transfection reagents, CD.siRNA nanoparticles only induced limited cytotoxic and neuroinflammatory responses in multiple brain-derived cell-lines, and also in vivo after single direct injections into the mouse brain. Alternatively, we have also described a PEGylation-based formulation approach to further stabilise CD.siRNA nanoparticles and progress towards a systemic delivery nanosystem. Resulting PEGylated CD.siRNA nanoparticles showed increased stability in physiological saltconditions and, to some extent, reduced protein-induced aggregation. Taken together, the work outlined in this thesis identifies modified CDs as effective, safe and versatile siRNA delivery systems that hold great potential for the treatment of CNS disorders, such as HD.
- ItemNovel strategies to enhance bumetanide concentrations in the brain in the treatment of neonatal seizures(University College Cork, 2015) Donovan, Maria D.; Cryan, John F.; Boylan, Geraldine B.; Griffin, Brendan T.; Irish Research CouncilSeizures are a prevalent neurodevelopmental disorder that affect up to 5/1000 newborns. Seizures result in detrimental developmental outcomes for many neonates, including mortality, disability and epilepsy. Current antiepileptic treatments, such as phenobarbital, display poor efficacy rates. Gamma-aminobutyric acid (GABA)-mediated signalling may promote excitatory neurotransmission in neonates with a birth injury due to intracellular accumulation of chloride. Bumetanide is a potential adjunct treatment for neonatal seizures, which reduces intracellular chloride concentrations by inhibiting the sodium-potassium-chloride cotransporter NKCC1. This accelerates the excitatory to inhibitory switch in GABA neurotransmission. In vitro bidirectional permeability assays were used to determine the apparent permeability of bumetanide and the potential for bumetanide efflux by organic anion transporter 3 (OAT3). Bumetanide was found to be a transported efflux substrate of human OAT3, thus OAT3 inhibition is a potential therapeutic augmentation strategy. OAT3 inhibition was investigated in vivo using an integrated intracerebral microdialysis model for the potential to augment bumetanide concentrations in the brain. Bumetanide was detected in brain extracellular fluid and this concentration increased after probenecid administration. An in vivo model of hypoxic-ischaemic neonatal seizures was established to quantify the pharmacodynamic effect of bumetanide in seizures. OAT3 inhibition enhanced the concentration of bumetanide in the brain in this model. Seizure burden in these animals was reduced significantly by phenobarbital and bumetanide and decreased further when an OAT3 inhibitor was administered. Physiologically-based pharmacokinetic modelling was employed to predict plasma and brain concentrations of bumetanide in a virtual neonatal population. The simulated brain tissue concentrations of bumetanide in neonates were below the half-maximal inhibitory concentration for the target transporter NKCC1. However, large interindividual variability and a paucity of physiological limited the accuracy of these simulations. In summary, augmentation strategies that focus on preventing bumetanide efflux from the brain via OAT3 may contribute to an improved outcome for neonates with seizures.
- ItemAntimicrobial stewardship in Ireland, with a focus on long term care facilities(University College Cork, 2015) Fleming, Aoife; Byrne, Stephen; Health Research BoardBackground: Antimicrobial resistance is a major public health concern, and its increasing incidence in the Long Term Care Facility (LTCF) setting warrants attention (1). The prescribing of antimicrobials in this setting is often inappropriate and higher in Ireland than the European average (2). The aim of the study was to generate an evidence base for the factors influencing antimicrobial prescribing in LTCFs and to investigate Antimicrobial Stewardship (AMS) strategies for LTCFs. Methods: An initial qualitative study was conducted to determine the factors influencing antimicrobial prescribing in Irish LTCFs. This allowed for the informed implementation of an AMS feasibility study in LTCFs in the greater Cork region. Hospital AMS was also investigated by means of a national survey. A study of LTCF urine sample antimicrobial resistance rates was conducted in order to collate information for incorporation into future LTCF AMS initiatives. Results: The qualitative interviews determined that there are a multitude of factors, unique to the LTCF setting, which influence antimicrobial prescribing. There was a positive response from the doctors and nurses involved in the feasibility study as they welcomed the opportunity to engage with AMS and audit and feedback activities. While the results did not indicate a significant change in antimicrobial prescribing over the study period, important trends and patterns of use were detected. The antimicrobial susceptibility of LTCF urine samples compared to GPs samples found that there was a higher level of antimicrobial resistance in LTCFs. Conclusion: This study has made an important contribution to the development of AMS in LTCFs. The complexity of care and healthcare organisation, and the factors unique to LTCFs must be borne in mind when developing quality improvement strategies.
- ItemStrategies to prevent potentially inappropriate prescribing and adverse drug reactions in older patients(University College Cork, 2015) Cullinan, Shane; Byrne, Stephen; O'Mahony, DenisINTRODUCTION: Potentially inappropriate prescribing (PIP) is a major contributor to adverse drug reactions and overall increased healthcare costs. The aim of this thesis was to identify, develop and implement strategies with the potential to prevent PIP and ADRs in older patients. METHODS: A systematic review of the qualitative literature (Meta-synthesis); A qualitative study in Irish hospitals; A randomised controlled trial (RCT) to assess the impact of an online educational module on doctors’ prescribing knowledge and confidence; Exploration of the potential for a frailty index score to enable doctors identify patients at increased risk of PIP and ADRs; Exploration of the potential for the SHiM tool to enable doctors to optimise prescribing for older patients. RESULTS: The meta-synthesis identified four key concepts: (i) Desire to please the patient; (ii) Feeling of being forced to prescribe; (iii) Tension between experience and guidelines; (iv) Prescriber fear. Similar themes also emerged from the qualitative study. In the RCT, the online educational module resulted in a highly significant 22% difference in test scores between intervention and control groups. The studies exploring the frailty index score showed a significant positive relationship between a patient’s frailty status and their likelihood of experiencing PIP/ADRs. Patients above a frailty threshold of 0.16 were at least twice as likely to experience PIP/ADRs. SHiM was found to be a useful tool in terms of reconciling patients’ medications. However, the evidence for it being capable of preventing clinically relevant adverse events was poor. CONCLUSION:Qualitative research in this thesis has proposed novel theories relating to the causative factors of PIP in older patients. In doing so, it has identified several areas for intervention and laid down a road map for future research.
- ItemEconomic evaluations of clinical pharmacy services in Ireland, 2007-2015(University College Cork, 2016) Gallagher, James; Byrne, Stephen; Mccarthy, Suzanne; Woods, Noel; Eustace, Joe; Health Research BoardIntroduction The concept of this thesis was driven by stagnation within the Irish healthcare system. Multiple reports from pharmacy organisations had outlined possible future directions for the profession but progress was minimal, especially in comparison with other countries. The author’s directive was to evaluate the economic impact of a series of clinical pharmacy services (CPS) in hospital and community settings. Methods A systematic review of economic evaluations of clinical pharmacy services in hospital patients was undertaken to gain insight into recent research in the field. Eligible studies were evaluated using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS), to establish the quality, consistency and transparency of relevant research. A retrospective analysis of an internal hospital pharmacy interventions database was conducted. A method first described by Nesbit et al. was implemented to estimate the level of cost avoidance achieved. A cost-effectiveness analysis based on data from a randomised controlled trial of a pharmacist-supervised patient self-testing (PST) of warfarin therapy is presented. Outcome measure was the incremental cost associated with six months of intervention management. A similar cost-effectiveness analysis based on previously published RCT data was used to evaluate a novel structured pharmacist review of medication in older hospitalised patients. Cost-effectiveness analysis was presented in the form of an incremental cost-effectiveness ratio (ICER). An ICER is an additional cost per unit effect, in the case of this study, the cost of preventing an additional non-trivial ADR in hospital. A method described by Preaud et al. was adapted to estimate the clinical and economic benefit gained from vaccination of patients by a community pharmacist in Ireland in 2013/14. Sample demographic data was obtained from a national chain of community pharmacies and applied to overall national vaccination data. Results Systematic review identified twenty studies which were eligible for inclusion. Overall, pharmacist interventions had a positive impact on hospital budgets. Only three studies (15%) were deemed to be “good-quality” studies. No ‘novel’ clinical pharmacist intervention was identified during the course of this review. Analysis of internal hospital database identified 4,257 interventions documented on 2,147 individual patients over a 12 month period. Substantial cost avoidance of €710,000 was generated over a 1 year period from the perspective of the health care provider. Mean cost avoidance of €166 per intervention was generated. The cost of providing these interventions was €82,000. Substantial net cost-benefits of €626,279 and a cost-benefit ratio of 8.64 : 1 were generated based on this evaluation of pharmacist interventions. Results from an evaluation of a novel pharmacist-led form of warfarin management indicated indicated that on a per patient basis, PST was slightly more expensive than established anticoagulant management. On a per patient basis over a six month period, PST resulted in an incremental cost of €59.08 in comparison with routine care. Overall cost of managing a patient through pharmacist-supervised PST for a six month period is €226.45. However, for this increase in cost a clinically significant improvement in care was provided. Patients achieved a significantly higher time in therapeutic range during the PST arm in comparison with routine care, (72 ± 19.7% vs 59 ± 13.5%). Difference in overall cost was minimal and PST was the dominant strategy in some scenarios examined during sensitivity analysis. Structured pharmacist review of medication was determined to be dominant in comparison to usual pharmaceutical care. Even if the healthcare payer was unwilling to pay any money for the prevention of an ADR, the intervention strategy is still likely to be cost-effective (probability of being determined cost-effective = 0.707). Implementation of pharmacist-led influenza vaccination has resulted in substantial clinical and economic benefits to the healthcare system. The majority of patients (64.9%) who availed of this service had identifiable influenza-related risk factors. Of patients with influenza-related risk factors, age ≥65 year was the most commonly cited risk factor. Pharmacist vaccination services averted a total of 848 influenza cases across all age groups during the 2013/2014 influenza season. Due to receipt of vaccination in a pharmacy setting, 444 influenza-related GP visits were prevented. In terms of more serious influenza-associated events, 11 hospitalisations and five influenza-related deaths were averted. Costs averted were approximately €305,000. These were principally wider societal-related costs associated with lost productivity. Conclusion Overall, clinical pharmacy services are adding value to the Irish healthcare system in both hospital and community settings, but provision of additional funding for new services would enable them to offer a great deal more.
- ItemGene delivery for the treatment of prostate cancer(University College Cork, 2016) Fitzgerald, Kathleen A.; O'Driscoll, Caitriona M.; Irish Cancer SocietyProstate cancer is one of the most common cancers diagnosed in men. Whilst treatments for early-stage disease are largely effective, current therapies for metastatic prostate cancer, particularly for bone metastasis, offer only a few months increased lifespan at best. Hence new treatments are urgently required. Small interfering RNA (siRNA) has been investigated for the treatment of prostate cancer where it can ‘silence’ specific cancer-related genes. However the clinical application of siRNA-based gene therapy is limited due to the absence of an optimised gene delivery vector. The optimisation of such gene delivery vectors is routinely undertaken in vitro using 2D cell culture on plastic dishes which does not accurately simulate the in vivo bone cancer metastasis microenvironment. The goal of this thesis was to assess the potential of two different targeted delivery vectors (gold or modified β-cyclodextrin derivatives) to facilitate siRNA receptor-mediated uptake into prostate cancer cells. Furthermore, this project aimed to develop a more physiologically relevant 3D in vitro cell culture model, to mimic prostate cancer bone metastasis, which is suitable for evaluating the delivery of nanoparticulate gene therapeutics. In the first instance, cationic derivatives of gold and β-cyclodextrin were synthesized to complex anionic siRNA. The delivery vectors were targeted to prostate cancer cells using the anisamide ligand which has high affinity for the sigma receptor that is overexpressed by prostate cancer cells. The gold nanoparticle demonstrated high levels of uptake into prostate cancer PC3 cells and efficient gene silencing when transfection was performed in serum-free media. However, due to the absence of a poly(ethylene glycol) (PEG) stabilising group, the formulation was unsuitable for use in serum-containing conditions. Conversely, the modified β-cyclodextrin formulation demonstrated enhanced stability in the presence of serum due to the inclusion of a PEG chain onto which the anisamide ligand was conjugated. However, the maximum level of gene silencing efficacy from three different prostate cancer cell lines (DU145, VCaP and PC3 cells) was 30 %, suggesting that further optimisation of the formulation would be required prior to application in vivo. In order to develop a more physiologically-relevant in vitro model of prostate cancer bone metastasis, prostate cancer cells (PC3 and LNCaP cells) were cultured in 3D on collagenbased scaffolds engineered to mimic the bone microenvironment. While the model was suitable for assessing nanoparticle-mediated gene knockdown, prostate cancer cells demonstrated a phenotype with lower invasive potential when grown on the scaffolds relative to standard 2D cell culture. Hence, prostate cancer cells (PC3 and LNCaP cells) were subsequently co-cultured with bone osteoblast cells (hFOB 1.19 cells) to enhance the physiological relevance of the model. Co-cultures secreted elevated levels of the MMP9 enzyme, a marker of prostate cancer metastasis, relative to prostate cancer cell monocultures (2D and 3D) indicating enhanced physiological relevance of the model. Furthermore, the coculture model proved suitable for investigating nanoparticle-mediated gene silencing. In conclusion, the work outlined in this thesis identified two different sigma receptor-targeted gene delivery vectors with potential for the treatment of prostate cancer. In addition, a more physiologically relevant model of prostate cancer bone metastasis was developed with the capacity to help optimise gene delivery vectors for the treatment of prostate cancer.
- ItemDevelopment of a dissolvable microneedle influenza vaccine patch(University College Cork, 2016) Allen, Evin A.; Crean, Abina; Moore, Anne; College of Medicine and Health, University College CorkDelivery of large molecular weight biological molecules to the epidermis and dermis is constrained by the tough outer layer of the epidermis, the stratum corneum (sc). Microneedle technologies attempt to overcome this physical barrier using sharp micron-size projections to penetrate the sc. Dissolvable microneedles (DMN), are a particular microneedle design whereby the needle structure is composed of a soluble matrix that upon application to the skin, dissolves releasing the vaccine load into skin. This thesis examines (1) the formulation and processing considerations around DMN fabrication, (2) the immunogenicity of DMN containing trivalent influenza vaccine (TIV) in pre-clinical mouse and pig models and (3) the thermostability of these DMN formulations during storage. The results demonstrate the importance of formulation for microneedle formation and mechanical strength. Trehalose and polyvinylalcohol based formulations produced optimal microneedle structures and were amenable to piezoelectric dispensing; allowing for precise multi-layered DMN to be fabricated. The effect of drying conditions was assessed and found to be critical for DMN mechanical strength and skin penetration. The antibody responses to TIV generated by DMN-mediated vaccination were comparable or greater to those induced by immunization with a commercial TIV via the IM route in mice. DMN mediated immunisation resulted in a significantly broader humoral response to heterotypic influenza viruses compared to IM delivery. Stored at 40°C, a licensed seasonal influenza vaccine incorporated into DMN array was thermostable for at least 6 month as determined by Single Radial Immunodiffusion and immunogenicity in mice. The thesis advances the field of DMN influenza vaccination by elucidating important processing and formulation considerations in the fabrication of highly reproducible DMN. It also demonstrated that DMN can induce broader, larger humoral responses than conventional IM administration while demonstrating enhanced accelerated stability. Crucially, this works advances an automated fabrication system that will allow for clinical translation of DMN.
- ItemA mixed method study to explore the impact of nurse prescribing in clinical practice(University College Cork, 2016) Creedon, Rena; Byrne, Stephen; Mccarthy, Suzanne; Kennedy, JuliaIntroduction The introduction of prescriptive authority for Irish nurses in 2007 was a significant change to the traditional function of the nurse’s role which extends the horizons for the future of the nursing profession in Ireland. However to-date there is limited evidence and research undertaken on the impact the initiative has had in the clinical setting. Therefore, the aim of this work was to: (i) review the literature relating to nurse prescribing to establish both nationally and internationally perspectives, (ii) identify the most applicable method of assessing issues established, (iii) examine the impact of nurse prescribing intervention on the appropriateness of prescribing for older adults and (iv) explore the use of a medication evaluation tool in practice. Methods Initially a comprehensive review of the literature was undertaken to establish the national and international perspectives of nurse prescribing. To understand the complexities of nurse prescribing and the interplays between the organizational structures, professional issues and patient impact on medication, a mixed methods study was undertaken that specifically allowed data to be viewed both objectively and subjectively. The researcher interprets to what extent and in what ways the two sets of data converge, diverge, relate to each other, and/or combine to create a better understanding in response to the study’s overall purpose. Results Evidence form the literature suggests that the impact of nurse prescribing on clinical practice is positive from a patient, healthcare professional and organisational perspective. However, the nurse prescriber’s role is ambiguous because it does not have a specific role description. Data collected through the MDS are restricted, incomplete and inaccurate especially pertaining to nurse prescriber’s workloads which have increased significantly since the introduction of the initiative. In addition, the collaborative practice agreement is proving to be restrictive in practice and reaffirms that overall responsibility for nurse prescribing remains with the doctor. Using an evaluation tool has the potential to improve safety and quality of prescribing that has an immediate effect on patient care. The competence and confidence levels of nurse prescribers in Ireland are comparable to their counterparts in the UK and Canada. Conclusion This thesis shows that nurse prescribing is highly prevalent to appropriate and timely care delivery in clinical practice. This work further demonstrates that the use of a structured medication evaluation tool in practice can significantly improve the appropriateness of prescribing and reduce the incidence of potentially inappropriate prescriptions and potential prescribing omissions for older individuals in hospital.
- ItemThe implementation of a family-focused lifestyle programme for managing childhood obesity in the community setting in Ireland(University College Cork, 2017) Kelleher, Emily Geraldine; Harrington, Janas; Perry, Ivan J.; Shiely, Frances; Mchugh, Sheena; Health Research BoardBackground and aim: Childhood obesity is a significant public health issue. International guidelines continue to recommend family-focused, multicomponent, childhood weight management programmes despite limited evidence on their effectiveness or implementation in real-world settings. In 2014, the Irish Health Service proposed a national pilot of the W82GO-community programme. The overall aim of this thesis was to investigate the barriers and facilitators to the implementation of W82GO-community and explore the factors influencing family engagement. Methods: W82GO-community aimed to improve nutrition, increase physical activity and facilitate behaviour change in children aged 5-7 years who measured ≥98th percentile over one year. It was piloted in two community sites by two multidisciplinary teams from April 2015 to April 2016. Firstly, a qualitative study was conducted to explore implementation from the perspective of 29 national and local level stakeholders responsible for implementing the programme including professionals from dietetics, psychology, public health nursing, physiotherapy, health promotion and administration. Framework analysis was used to identify barriers and facilitators which were mapped onto a well-known implementation framework. Secondly, a systematic review of international literature was carried out to investigate what factors influence attendance at similar community-based lifestyle programmes among families of overweight or obese children. This was followed by another qualitative study exploring public health nurses (PHNs) experiences of referring families to, and families’ feelings of being referred to, W82GO-community. It also investigated families’ motivation to participate in and complete treatment. Finally, in light of findings from the aforementioned studies a cross-sectional analysis of data collected as part of the Cork Children’s Lifestyle Survey (CCLaS) was conducted to identify factors influencing parent and child misperception of child weight. Results: For all stakeholders, barriers to the implementation of W82GO-community arose due to the multidisciplinary nature of the programme, including the lack of role clarity and added complexity of working in different locations. Furthermore, a lack of parental engagement, as evidenced by low enrolment and retention rates, presented a further challenge for programme implementation. Of the 121 children who were eligible for initial assessment, less than half of families accepted the invitation and of those who presented, 19 subsequently started the programme. Just eight families completed the W82GO-community programme. The systematic review on barriers and facilitators to family attendance and retention found that parents are largely driven to enrol because of a concern for their child’s psychological health and wellbeing. However, the stigma surrounding excess weight and the denial of the issue amongst some parents presents significant barriers to enrolment. The systematic review findings also suggest that over the course of a programme, children’s positive social experiences such as having fun and making friends foster the desire to continue participating in treatment. Results from our qualitative study involving PHNs and parents who participated in W82GO-community found that both PHNs and parents were fearful of the referral process. They had concerns about both the practicality of making the referral and the significance of the referral on the health and wellbeing of the child, respectively. Despite these initial fears, parents concern for their child’s future was a major driver behind their participation. Finally, the cross-sectional analysis of CCLaS data highlighted that 45% of parents of overweight/obese children underestimated their child’s weight and this was influenced by child age and child misperception of own weight. 77% of overweight/obese children misclassified their own weight. Conclusion: This thesis provides critical evidence on the complexities associated with implementing a multidisciplinary childhood weight management programme in real-world settings. It provides practical recommendations to guide future policy makers, programme delivery teams and researchers, in particular, when developing strategies to boost recruitment, minimise attrition and subsequently enhance effectiveness. Findings highlight the profound limitations of family-focused, community-based, weight management programmes and confirm the critical need for broader societal intervention.
- ItemKnowledge, attitudes and beliefs of parents on fever and febrile illness in children(University College Cork, 2017) Kelly, Maria; Sahm, Laura; Mccarthy, Suzanne; O'Sullivan, Ronan; Shiely, FrancesIntroduction Fever (temperature ≥38OC) is a common childhood symptom and sign, leading to concern and anxiety in parents. The aim of this research was to help parents to treat their child appropriately when they have a fever and to recognise serious illness. Methods Systematic reviews of the qualitative and quantitative literature were undertaken. An empirical qualitative study using semi-structured interviews was conducted at the ante-natal clinics associated with Cork University Maternity Hospital. A complementary study was conducted in Denmark. A large-scale questionnaire study was conducted with parents across Ireland using a previously validated questionnaire. The questionnaire was administered using webpages and websites identified in the previous qualitative study. From the results of previous work, an information leaflet was designed. A randomised controlled trial was conducted to assess the impact the information leaflet had on parental knowledge of fever and correct management strategies. Results Results from the systematic reviews suggest that fever phobia, a concept which was first described in the 1980’s, is present. Myths concerning fever continue to exist and a lack of evidence-based knowledge fails to challenge their existence. Results from the qualitative study showed that parents had a general rather than a specific knowledge of fever. When knowledge was tested on a large-scale, results showed that parents’ knowledge of fever was poor, with only a small number of parents knowing the correct definition of fever. Many fever management practices favoured by parents contrasted with recommendations in guidelines. The introduction of a fever information leaflet increased parental knowledge of correct fever temperature definition and management practices. Conclusions Parental knowledge of fever, febrile illness and evidence-based management practices are poor, based on results from this sample. This research has shown that relatively simple educational interventions are vital to equip parents with the correct knowledge to define and manage fever effectively.