Medication errors are a significant global concern and can cause serious medical consequences in children. Double checking of medicines by two nurses is one strategy used by many children's hospitals to prevent errors from reaching paediatric patients. This thesis involves different studies that evaluated the effectiveness of the double checking process in reducing and preventing medication administration errors in a children's hospital. In addition, a systematic review was conducted of medication errors studies in the Middle East. A systematic review was also conducted of published studies of double checking. Six electronic databases were searched for articles that assessed the double checking process during the administration of medicines. Sixteen articles were identified. Only one of them was a randomised controlled clinical trial in a clinical setting. Only one study was conducted in a children's hospital. The review found that there is insufficient evidence to either support or refute the practice of double checking and more clinical trials are needed to evaluate the double checking process in children's hospitals. Based on the findings that were highlighted from the systematic review, a prospective observational study of paediatric nurses using the double checking process for medication administration was undertaken. The study aimed to evaluate how closely double checking policies are followed by nurses in different paediatric areas, and also to identify any. medication administration errors during the study period. 2,000 drug dose administration events were observed. There was variation between paediatric nurses adherence to double checking steps and different medication administration errors were identified. Based on the observational study, a semi-structured questionnaire study was developed. It was designed to explore the paediatric nurses' knowledge and opinions about the double checking process. The study showed that many nurses have insufficient knowledge on the double checking process and the hospital policy for medication administration. A simulation study was conducted to examine whether single or double checking is more effective in detecting and reducing medication errors in children. Each participant in this study was required to prepare and administer medicines in scenarios for two "dummy patients" either with another nurse (double checking) or alone (single checking). Different confounders were built into each scenario (prescribing and administration) for nurses to identify and address during the administration process. Errors in drug preparation, administration and failure to address confounders were observed and documented. The main findings from this study were that the double checking process is more likely to identify medication administration errors and contraindicated drugs than single checking. The time taken for drug administration was similar for both processes. Another systematic review was conducted to identify the published medication errors studies that have been undertaken in the Middle East. The review identified 45 studies from 10 Middle Eastern countries. Nine of the studies focused on medication errors in paediatric patients. Educational programmes on drug therapy for doctors and nurses are urgently needed in the Middle East. These studies have contributed to the field of medication safety by providing more information about double and single checking medication administration processes in paediatric hospitals. More educational and training programmes for nurses about the importance of double checking and improving their adherence rate to the double checking steps during medication administration are required to improve its effectiveness.

Fenofibrate is a PPARα agonist, used to treat dyslipidemia. Unpublished work that has been previously carried out in our group has identified that fenofibrate also displays affinity for the cannabinoid receptors, CB1 and CB2. A dual receptor ligand, with the PPARα agonist activity of fenofibrate, combined with antagonist activity at the CB1 receptor, or agonist activity at the CB2 receptor, could reduce appetite, decrease plasma triglyceride levels, increase high density lipoprotein (HDL) levels, lower low density lipoprotein (LDL) levels and reduce atherosclerosis. This could enable the multi-symptomatic treatment of obesity with the advantage of avoiding side effects associated with taking multiple medications. However, whilst fenofibrate has affinity for the cannabinoid receptors, only its active metabolite; fenofibric acid (10b) activates PPARα. This project sought to develop novel ligands for the cannabinoid receptors that retain activity at PPARα. A series of amide derivatives of fenofibrate were synthesised, and pharmacological testing revealed that the piperidinyl (48g) and morpholino (48h) derivatives had agonist activity and a higher affinity for the cannabinoid receptors than fenofibrate. However these derivatives failed to bind and activate PPARα. Although a dual PPARα / cannabinoid receptor ligand has not been found with these amide derivatives, the compounds synthesised could provide a platform for the further development of cannabinoid receptor ligands of this novel class. This was demonstrated by further modifications to compounds (48g) and (48h) which indicated that activity at the cannabinoid receptors is tuneable.

Marfan Syndrome is a genetic, cardiovascular disease caused by a defect in the fibrillin 1 gene on chromosome 15. This defect causes abnormal deposition of elastin throughout the body. Elastin is found in many organs including the aorta. Marfan Syndrome is diagnosed by the Ghent criteria. The mean age at death is 44 years for men and 47 years for women, and about 70% die from acute cardiovascular complications, mainly aortic dissection. The assessment and treatment of the aortic complications of Marfan Syndrome has not changed for many years. Serial echocardiography is performed to measure the aortic root diameter. If thought to be increasing in size, beta blockers are prescribed to delay aortic dilatation and surgery, and to prevent aortic dissection or rupture despite the paucity of good research data. I have investigated three novel diagnostic tools: Tissue Doppler Imaging, Applanation Tonometry and Wave Intensity Analysis which have potential advantages in the assessment of the left ventricle and aorta and their interaction in Marfan Syndrome. I also investigated three drugs a beta blocker, an angiotensin converting enzyme inhibitor and a calcium channel blocker to look at their impact on some of the parameters measured by these three novel tools in a double-blinded, randomised cross-over trial. I conclude that these three novel tools would be useful adjuncts in monitoring Marfan Syndrome and their response to treatment. I also found that beta blockers may still have a role to play in delaying and preventing aortic complications when given together with an angiotensin converting enzyme inhibitor, calcium channel blocker or angiotensin receptor blocker. There are, however, other issues that need addressing to improve the management of the cardiovascular complications of Marfan Syndrome. This includes a multi-team approach to this multi-system disease and improvements in the standard of research.

P2Y12 antagonists are pharmacological agents used clinically in advanced stages of coronary artery disease in order to inhibit ADP-induced activation and aggregation of platelets and prevent deadly thrombotic events. Of the orally-prescribed P2Y12 antagonists available clopidogrel is the most established, it exhibits an excellent safety track record and is a popular drug, and was accredited for years the second-best selling drug in the world. However, since clopidogrel was introduced to the market in 1997 many pleiotropic effects have been noticed, which suggest other off-target yet beneficial effects in addition to its anti-platelet effects. The overall hypothesis being tested in this body of work was that P2Y12 antagonists, clopidogrel in particular, have the positive influence on vascular NO signalling. A vascular model was set up using isolated rabbit aortae in which clopidogrel enhanced NO donor-induced vasorelaxation. Although the precise mechanism was not found, the effect was independent of P2Y12 receptors and possibly linked to decreased superoxide production and improved anti-oxidant/inflammatory status in vessels. This finding might be relevant for patients receiving concomitant therapy with organic nitrates and clopidogrel. In vitro studies revealed novel S-nitrosation properties of P2Y12 antagonists, surprisingly without the need for metabolism to their active form. Newly synthesized SNO derivatives of clopidogrel and prasugrel were more potent in inhibition of platelet aggregation and induction of vasodilation than their parental forms. Although the formation of drug-SNO species has to be confirmed in vivo, they have a potential to increase NO bioavailability in patients. Clopidogrel administration to coronary artery disease patients resulted in upregulated plasma levels of nitrite and cGMP after 2 h-intake of a loading dose, which were further increased after 3 days of a maintenance therapy. This effect was never shown before in man and most likely reflects improved endogenous NO production, but also providing additional protection from the effects of nitrite at the same time. Taken together, the results of this thesis clearly demonstrate the influence of clopidogrel on vascular response to NO as well as NO production, metabolism and bioavailability. It is important to identify these alternative pathways especially in the current era with alternative P2Y12 antagonists that overcome some of the limitations of clopidogrel but may not share all the beneficial properties.

In summary, these observations demonstrate that lung function appears to be impaired by mucus secretion in an experimental animal model of chronic allergic asthma. The guinea pig model of chronic asthma may be utilised to investigate the development of a mucus hypersecretory phenotype in asthma or identify potential targets for the development of novel therapies aimed at reducing goblet cell mucus production or secretion.

Clostridium difficile is one of the UK’s most common hospital acquired infections and there is anecdotal evidence to suggest that the bacteria are sensitive to the antibacterial properties of tea. Surprisingly, little research has been undertaken to characterise the inhibitory activity of aqueous tea infusions that are representative of traditional drinking habits. The antibacterial properties of tea are thought to be due to a group of polyphenols called catechins. However, their contribution to the inhibitory activity of tea infusions and their mechanism of action is still subject to debate. An antimicrobial assay, developed using Staphylococcus aureus as a model organism, was used to determine the antibacterial activity of a range of tea infusions against 75 clinical isolates of C. difficile that represented all the major strain ribotypes over 11 years. Green teas demonstrated more potent antibacterial activity than black teas and their activity was positively correlated with antioxidant power, hydrogen peroxide production, and catechin content. Furthermore, the country of origin of the tea affected the catechin content and subsequent antimicrobial activity of the infusion. Detailed chemical analysis using high performance liquid chromatography and counter current chromatography suggests that the antibacterial activity of tea is probably the result of synergistic interactions between a number of catechins rather than the activity of an individual compound. With regards to the mode of action by which tea inhibits C. difficile, electron microscopy studies of the bacterium treated with green tea revealed distinct changes to the outer cell structures of the bacteria. These changes were indicative of cell membrane blebbing, thus supporting the theory that tea compounds interact with the bacterial membrane and/or cell wall. Overall, this investigation concluded that tea infusions have inhibitory activity against C. difficile in vitro and may be useful in the treatment or prevention of C. difficile infections in vivo.

Antibacterial resistant infections are one of the most challenging problems affecting healthcare and have developed through the overuse of antibiotics and a shortage of new treatments progressing to market. Natural products are the initial source of most antibiotics currently available and marine sponges are a known resource of novel antibacterial compounds; although well-­‐studied marine sponges found in UK waters have been scarcely explored. An examination of the chemical research on sponges identified previously unstudied species for collection in both Greece and Wales. Sequential solvent gradient extraction was optimised, to best exploit the material collected, providing three crude extracts for each sponge collected. A significant difference was observed between the chemical composition of sponges collected from Greece and Wales. An efficient antimicrobial assay was developed to screen each extract against clinically relevant organisms; allowing the direct identification of activity on an eluted thin layer chromatography plate. This overlay data was used for detailed chemical analysis using high performance counter current chromatography, with some separated fractions displaying greater activity towards the bacterium methicillin resistant Staphylococcus aureus (MRSA) than vancomycin. The parent masses of compounds responsible for activity were identified by directly coupling the overlay assay data to mass spectrometry, identifying multiple novel parent masses. Dereplication of samples was completed using the database MarinLit and the construction of a molecular network to compare fragmentation patterns in mass spectra. Bacterial cultivation from Welsh sponge samples isolated 18 antibacterial strains, which were identified using 16S rRNA analysis. Four of these strains were previously uncultured. Chemical analysis was also completed, on two unstudied strains, identifying further active novel parent masses, with no parent mass crossover to the host sponge. Overall, this investigation concluded that marine sponges are excellent source of novel antibacterial compounds, which can display activity against clinically relevant bacteria equivalent to current treatments.

Intravenous lipid emulsions are used ubiquitously through the medical field as a source of parenteral nutrition. Development of new formulations requires an understanding of the metabolism of the product. Current methods of rate determination and of metabolism analysis have several drawbacks. Radioactive labelled assays have lower biological relevance, are time consuming due to separation steps and require long substrate preparation. Existing fluorescence assays based around triglyceride hydrolysis are impractical in emulsion systems due to high signal-noise ratio as well as the use of non-specific fluorescent dyes. Colorimetric methods such as the non-esterified fatty acids (NEFA) assay is expensive, requires multiple steps and specialised machinery. Due to the limitations of these techniques we developed a novel fluorescent assay using a lipoprotein lipase specific substrate incorporated into lipid emulsions. The lipoprotein lipase substrate, EnzChek® Lipase Substrate, green fluorescent, 505/515, is based on a triglyceride structure with a fluorescent dye at the Sn1 position and a dark quencher at the Sn2 position. LPL cleaves preferentially at the Sn1 position of triglycerides, which separates the dye from the quencher creating a fluorescent signal. The signal can then be detected using a fluorescent plate reader. Both lipid emulsion particles and EnzChek are substrates for LPL, so the hydrolysis of EnzChek is analogous for native emulsions particles. Over time, in the presence of LPL, fluorescent signal increases as more EnzChek is hydrolysed in tandem with emulsion particles. We have designed a range of emulsions with varied oil and surfactant composition. Using the EnzChek emulsion assay detailed above we are able to follow the rate of metabolism in real-time. This assay has been tested and found to be robust and reproducible. It is able to investigate differences in metabolism between Soybean oil, medium-chain triglyceride and fish oil emulsions. As well as changes in surfactant type and concentration.

At the height of its popularity, mephedrone was the most common recreationally used cathinone. This is thought to be due to its perceived likeness to MDMA. Therefore the aim of this thesis was to examine mephedrone-induced changes in behaviour, body temperature or neurochemistry in the rat and to compare these changes to those observed following MDMA administration. This was achieved by assessing changes in body temperature following acute mephedrone, MDMA, cathinone or methcathinone administration. Additionally, locomotor activity and cognitive tasks were performed following chronic intermittent administration of mephedrone, MDMA or cathinone. These behaviours, as well as mephedrone-induced changes to body temperature and ‘anxiety-related’ behaviour, were also assessed following either pre-treatment with MDMA or co-administration of caffeine. Finally, locomotor activity, body temperature changes and in vivo striatal dopamine release were assessed following rapid repeated dosing of mephedrone, and the roles of dopamine, 5-HT and noradrenaline in these responses were examined. Post mortem monoamine concentrations from specific brain regions were also assessed following acute, chronic intermittent and rapid repeated dosing of mephedrone. It was found that the neurochemical, behavioural and physiological effects of mephedrone in the rat include hyperactivity, hypothermia, cognitive deficits, anxiety-related behaviour and increased striatal dopamine efflux. Pre-exposure to MDMA, or concomitant caffeine administration, caused an increase in rectal temperature following mephedrone injection while caffeine co-administration prolonged the hyperactive profile of mephedrone. Importantly, unlike MDMA, rapid repeated mephedrone administration (3 x 10 mg kg-1 at 2 h intervals) had no cumulative effect on mephedrone-induced hypothermia or hyperactivity. It is also clear that mephedrone is inducing its effects via noradrenergic, dopaminergic and serotonergic mechanisms. The cathinones and MDMA had varying effects on post mortem tissue levels of the monoamines and their metabolites. Importantly, these effects of mephedrone appear to be occurring by mechanisms that are different, but similar, to MDMA.

Type 1 diabetes is an autoimmune disorder caused by the destruction of insulin secreting ß cells in the pancreas. The aim of this project is to explore the potential of using solid-coated microneedles to target skin dendritic cells with an auto-antigen to induce tolerance for the treatment of type 1 diabetes. A novel coating formulation has been developed to accommodate peptides with different lipophilicities. The optimised coating formulation and electro-polishing of the microneedle surface were key factors which enhance the efficiency of peptide delivery. Optimised coating formulation did not show adverse effects on peptide bioactivity or trigger a pro-inflammatory response. The delivery route (microneedle vs. intradermal injection) was shown to be the main factor that influenced the clearance of peptide from murine skin in vivo. Other factors such as temperature, skin hydration state and peptide solubility were also shown to have effects on peptide clearance. Two autoantigens were used to induce tolerance in non-obese diabetic mice – a potent mimotope m31 and endogenous antigen WE14. The proliferation profile of transferred carboxyfluorescein succinimidyl ester labelled BDC2.5 T cells in pancreatic lymph nodes in non-obese diabetic mice was used as a readout for the development of immunological tolerance. The results herein provide the first demonstration that WE14-coated microneedles were able to induce tolerance in vivo, showing reduced proliferation of BDC2.5 T cells. Additionally, this project examined the potential of short-term topical application of betamethasone to enhance peptide-induced tolerance. Both human and mouse dendritic cells showed a pro-tolerogenic state after treatment with topical application of betamethasone in vitro. However, full dose betamethasone was shown to have systemic toxicity in vivo, resulting in depletion of CD11c+ dendritic cells and CD4+ T cells. Diluted topical betamethasone facilitated a small effect on BDC2.5 proliferation; however no advantage on enhancing antigen specific immunotherapy was observed.