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THESIS SUBMITED IN FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE OF MASTER OF TECHNOLOGY OF PRIMARY HEALTH CARE IN THE FACULTY OF HEALTH AND WELLNESS SCIENCES AT THE CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2009 / Numerous sources including the World Health Organization (WHO) and International Diabetes Federation (IDF) reported that a diabetes epidemic, with a parallel rise in obesity and insulin resistance is presently enveloping the world. Type 2 diabetes mellitus accounts for over 80% of all diabetics in most countries and has been recognized as a global epidemic, with its prevalence increasing at a rapid rate in both developed and developing countries. Up to 80% of type 2 diabetic cases can be preventable by changing diet, increasing physical activity and improving the living environment. The prevalence of diabetes in South Africa varies from one province to another and within different population groups. The highest rates have been reported among Asian Indians and the mixed ancestry populations, however, data is limited. Urbanization and industrialization which come along with westernized lifestyles such as sedentarism, consumption of high fat diets consequently resulting into obesity are some of the factors implicated in the development of type 2 diabetes. With type 2 diabetes prevalence rate increasing at an alarming rate, both in industrialized and also in developing countries, every factor associated with the development of diabetes needs to be explored and addressed. Before progression to diabetes, the diabetic state is preceded by a glucose regulation disorder commonly referred to as impaired glucose tolerance which may last for several years. Another form of glucose metabolism disorder other than diabetes is impaired fasting blood glucose level. While some cases of diabetes are often undiagnosed, it has also been noted that for every one diagnosed diabetic, there could be another that is undiagnosed. As has been shown in this study, many people could be walking with diabetes which is undiagnosed. The aims of this study were to determine: The prevalence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), diabetes mellitus and the risk factors for developing diabetes amongst the 35 – 65 year old population of Bellville South, Cape Town South Africa. In a cross-sectional survey, 600 subjects within the age group of 35-65 years selected through stratified random sampling within the Bellville South area of Cape Town underwent an oral glucose tolerance test. Diabetes, IGT and IFG were determined using both the American Diabetes Association (ADA) and the revised WHO criteria. Subjects also underwent several anthropometric measurements. Personal demographic, family, health and lifestyle data were extrapolated by use of a questionnaire. The prevalence of diabetes did vary between the two criterion used. The prevalence of newly diagnosed diabetes was 77 (12.8%) using the WHO criteria and 62 (10.3%) using the ADA criteria. Overall, the prevalence of diabetes was 25.6 % of which 12.8 % were newly diagnosed. IGT was present in 24 (4.0%) whilst IFG was in 179 (29.8%) using the WHO and ADA criterion respectively. Females were more affected than males and the prevalence of diabetes increased with age. Although overweight did not differ significantly between males and females, the latter were significantly more obese across all age groups (p < 0.05). Presence of a first degree relative with diabetes mellitus, particularly the father was significantly associated with development of diabetes, (odds ratio = 2.092, 95% CI 1.109 – 3.949, p = 0.023). Though more than 40% of the population studied was shown to engage in heavy drinking (30g of alcohol per day), it was not associated with diabetes. There has been a 10.4% increase in the prevalence of diabetes in this population group compared to what was reported more than a decade ago. Of great concern is the number of individuals with undiagnosed diabetes.

Introdução e objetivos: Muitos trabalhos descrevem alterações no metabolismo da glicose em pacientes com zumbido. Diversos autores relatam a presença da hiperglicemia e / ou hiperinsulinemia e que isso seria um fator associado ao zumbido. Outros relatam a hipoglicemia, especialmente pós-prandial, com ou sem hiperinsulinemia. Há muita controvérsia sobre a patogênese do zumbido e sobre o real papel de glicose e insulina na gênese deste sintoma. O objetivo deste estudo foi analisar os níveis de glicose e suas excursões, assim como da insulina de jejum em pacientes com zumbido e um grupo de controles saudáveis. Materiais e Métodos: Vinte pacientes foram selecionados aleatoriamente a partir do Ambulatório de Zumbido do hospital. Também vinte pacientes sem zumbido da mesma instituição ajustados para idade, sexo e IMC foram selecionados. O monitoramento da glicose foi feito pelo um sistema de monitorização contínua da glicose (CGMS, Medtronic, EUA) durante 72 horas. A insulina de jejum foi medida por um ensaio quimioluminescente (Roche, Brasil). 9Continua) Resultados: Os resultados são expressos em média ± DP; os primeiros valores apresentados são para pacientes com zumbido. Os dois grupos não diferiram quanto à idade (53 ± 12 vs 53 ± 13 anos), IMC (28 ± 6 vs 27 ± 6 kg/m2) e glicemia de jejum (93,0 ± 7,0 vs 95,0 ± 6,4 mg / dL). No CGMS, tanto a glicemia mínima (72 ± 12 vs 76 ± 15 mg / dL, P = 0,352), a máxima (145 ± 25 vs 146 ± 16 mg / dL, P = 0,816) , a média (106 ± 17 vs 106 ± 12 mg / dL, P = 0,994 valores de glucose) e amplitude de glicose(73 ± 26 vs 70 ± 19 mg / dL, P = 0,730) foram semelhantes nos dois grupos. A glicose pós-prandial de 2 horas também foi semelhante (101 ± 20 vs 100 ± 25 mg / dL, P = 0,947). A única diferença significativa foi a glicemia mínima no terceiro dia (68 ± 15 mg / dL vs 80 ± 20 mg / dL, P = 0,03). Insulina de jejum (7,8 ± 4,7 μUI / mL vs 10,4 ± 6,0 μUI / mL, P = 0,132), HOMA-IR (1,81 ± 1,12 vs 2,50 ± 1,40, P = 0,095) e HOMA-BETA (96 ± 60 vs 116 ± 74 - P = 0,132) não foram diferentes nos dois grupos. Apenas nas mulheres, a medida da cintura abdominal (82 ± 10 cm vs 99 ± 9 12 cm, P = 0,026) e razão cintura-quadril (0,95 ± 0,10 vs 0,92 ± 0,68, P = 0,002) foram significativamente diferentes , sendo menores nos pacientes com zumbido. Conclusão: Com exceção da glicemia mínima no terceiro dia, as medidas da glicose e da insulina foram semelhantes em ambos pacientes com e sem zumbido. Neste trabalho, as alterações tanto da glicose como da insulina não puderam explicar o zumbido.

UDP-glucose, the precursor for cellulose biosynthesis, can be produced via the catalysis of sucrose by sucrose synthase (SuSy) or through the phosphorylation of glucose-I-phosphate by UDP-glucose pyrophosphorylase (UGPase). As such, these genes, together with sucrose phosphate synthase (SPS) which recycles fructose (an inhibitor of SuSy), are interesting targets for altering carbon allocation in plants. In an attempt to alter cell wall biosynthesis in plants, targeted overexpression of SuSy, UGPase and SPS independently and in a pyramiding strategy was assessed in tobacco. All lines displayed enhanced growth and biomass production, and in the case of double and triple transgenics, there was an additive effect. Despite the increased growth rates, there was no consistent change in soluble carbohydrate pools. Furthermore, only the triple transgenics had constant changes in structural carbohydrates: with increased hemicellulose content and slight increases in cellulose. Collectively, these results support the role of SPS, SuSy and UGPase in maintaining sink strength, but suggest that the reallocation of carbon to cellulose production in tobacco may not be possible by overexpressing these genes. In contrast, transgenic poplar overexpressing UGPase produced significantly more cellulose than wild-type trees. However, this was accompanied by a severe reduction in growth and the production of a salicylic acid glucoside (SAG) in significant quantities. The UDP-glucose generated by UGPase overexpression appeared to participate in both the synthesis of cellulose and SAG, suggesting that cellulose biosynthesis may be limited by the cellulose synthase complex. Poplar transformed with SuSy and with SuSy x UGPase also had increased cellulose production. The trees were phenotypically normal, with only minor reductions in height growth in some lines. It appears that UDP-glucose may be channelled directly to the cellulose synthase complex by SuSy. The increased cellulose content was associated with an increase in cell wall crystallinity, but there was no change in microfibril angle, confirming the re-allocation to cellulose synthesis was not the result of tension wood formation, again supporting the hypothesis that the cellulose synthase complex is the limiting factor. Clearly, it is possible to alter cellulose deposition in trees by augmenting sucrose metabolism to produce UDP-glucose, the precursor to cellulose biosynthesis. / Forestry, Faculty of / Graduate

Dans l’intestin, le récepteur P2X7, un membre unique de la famille P2X, est fortement exprimé à la surface des cellules épithéliales intestinales le long des villosités, ce qui suggère un autre rôle pour ce récepteur que l’induction de l’apoptose des cellules à l’apex des villosités. Dans des modèles de cellules intestinales, nous avons mis en évidence qu’à la suite de l’activation du récepteur P2X7, la translocation à la membrane de GLUT2, le transporteur facilité du glucose, du fructose et du galactose dans l’intestin, était diminuée. Cette diminution d’expression s’accompagne d’une diminution d’absorption dans les cellules IEC-6 et d’une diminution du transport transcellulaire à travers une monocouche de cellules Caco-2 différenciées. En fait, comme nous l’avons montrée, l’internalisation de GLUT2 est induite par une voie de signalisation impliquant les protéines PI4K, PLC[gamma]-1, PKC[delta] et PKD1. Nous avons alors entrepris une série d’études pour déterminer quel était l’impact d’une délétion du gène P2rx7 sur le métabolisme du glucose dans un modèle de souris pour lequel l’expression de P2rx7 est invalidée (P2rx7-/-). Dans ce modèle, nous avons mesuré que les souris P2rx7-/- ont une masse significativement plus grande dès le sevrage. Des tests de tolérance au glucose sur des souris âgées de 3 semaines montrent une hyperglycémie qui se traduit par une concentration maximale de glucose sanguin plus élevé que le maximum de glycémie mesuré chez les souris normales. Cet état évolue à l’âge de 12 semaines avec une glycémie qui reste plus forte jusqu’à 90 min dans les souris P2rx7-/- par rapport aux souris contrôles. Nous avons également observé chez ces souris un taux d’insuline et de triglycérides significativement plus haut. La glycémie à jeun est aussi plus haute de façon significative à partir de 12 semaines. Cette différence de glycémie peut s’expliquer par une expression plus importante du transporteur GLUT2 à la surface apicale des cellules épithéliales dans le jéjunum des souris mutantes. Cette insertion systématique du transporteur semble favoriser une absorption rapide du glucose et le transport transcellulaire de celui-ci dans le sang. Enfin, l’augmentation de la glycémie a des conséquences sur le foie puisque les souris P2rx7-/- ont la voie de la lipogenèse active au sevrage et développent une stéatose hépatique avec accumulation croissante avec le temps de gouttelettes lipidiques dans le cytoplasme des cellules. L’ensemble des données suggère que le récepteur P2X7 joue un rôle majeur dans l’homéostasie du glucose.

L'immobilisation d'enzymes sur des supports conducteurs d’électricité est nécessaire afin d’améliorer leur bioactivité et leur stabilité, pour une utilisation et une réutilisation dans des applications dépendant de la réponse bio-électrochimique, telles que des bioélectrodes, des biocapteurs ou des piles à biocarburant. Cependant, les méthodes d'immobilisation utilisées rencontrent encore de nombreux défis en termes de risques pour la santé et d'impact environnemental. Il est donc important de trouver des approches équilibrées et respectueuses de l’environnement pour parvenir à une immobilisation efficace avec un minimum de conséquences néfastes. Ainsi, dans le cadre de cette thèse, l’utilisation d’écotechnologies telles que le plasma froid, le dépôt de polymère conducteur biocompatible (PEDOT: PSS) et d’un agent de réticulation biologiquement basé sur la génipine, peu toxique, permettant l'immobilisation de glucose oxydase (GOx) sur des textiles nontissés à base de fibres de carbone a été étudiée. Ces textiles à base de carbone, quelle que soit leur hydrophobicité, sont des matériaux robustes à utiliser comme alternative aux métaux rigides onéreux, car ils possèdent une bonne conductivité électrique et une bonne résistance à la corrosion dans différents milieux. Les résultats obtenus ont montré que le traitement plasma froid avec un mélange gazeux d'azote et d'oxygène était efficace pour fonctionnaliser la surface des nontissés de carbone vierge et ceuxrevêtus de PEDOT: PSS. Une augmentation des énergies de surface des fibres de carbone facilite l’immobilisation de GOx par adsorption physique avec une bioactivité maintenue et une meilleure capacité de réutilisation. En outre, l’immobilisation de GOx au moyen de génipine en tant qu’agent de réticulation améliore de façon remarquable la stabilité des performances des feutres de carbone bio-fonctionnalisés. Cet agent de réticulation s'est révélé capable de réticuler directement les enzymes sans matrice ni hydrogel. Enfin, les textiles de carbone bio-fonctionnalisés obtenus ont été principalement évalués pour une utilisation dans des applications durables pour le traitement des eaux usées telles que la Bio-Fenton (BF) et la Bio-Electro-Fenton enzymatique (BEF). Les résultats ont montré que la bioactivité et la bio-activité électrique du GOx immobilisé étaient prometteuses pour l’élimination de la couleur du colorant réactif Remazol Blue RR et sa dégradation partielle à partir de la solution dans les deux traitements, ce qui a prouvé l’efficacité des méthodes d’immobilisation choisies pour la production de textiles bioactifs. Ces textiles peuvent être utilisés comme électrodes pour la production d'énergie et la dépollution. / Enzyme immobilization on electrically conductive supports is necessary to improve their bioactivity and stability, for use and re-use in applications depending on bio-electrochemical response, such as in bioelectrodes, biosensors, or biofuel cells. However, the immobilization methods used are still facing many challenges in terms of health hazards and high environmental impact. Thus, it is important to find balanced and eco-friendly approaches to achieve efficient immobilization with minimum harmful consequences. Hence, within the frame of this thesis, the use of eco-technologies such as cold remote plasma, a bio-compatible conductive (PEDOT:PSS) polymer coating, and a bio-based crosslinker “genipin” which has low toxicity, to immobilize glucose oxidase (GOx) enzyme on conductive carbon fiber-based nonwoven textiles was investigated. These carbon-based textiles, regardless of their hydrophobicity, are robust materials to be used as alternative for expensive rigid metals, since they possess good electrical conductivity and good resistance to corrosion in different media. The results obtained showed that cold remote plasma treatment with nitrogen and oxygen gas mixture was efficient in functionalizing the surface of carbon felts and PEDOT:PSS coated felts. This increased carbon fiber surface energies, and facilitated the immobilization of GOx by physical adsorption with maintained bioactivity and improved reusability. Furthermore, immobilization of GOx using genipin as a crosslinking agent improved remarkably the stability of performance of bio-functionalized carbon felts. This crosslinker showed to be able to directly crosslink the enzymes without a matrix or hydrogel. Finally, the obtained bio-functionalized carbon textiles were primarily evaluated for use in sustainable applications for wastewater treatment such as Bio-Fenton (BF) and enzymatic Bio-Electro-Fenton (BEF). The results showed that bioactivity and bio-electro-activity of immobilized GOx was promising in color removal of Remazol Blue RR reactive dye and its partial degradation from solution in both treatments, which proved the success of the chosen immobilization methods in producing bioactive textiles that can be used as electrodes for power generation and pollution control.

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Traditional methods of blood glucose monitoring involve obtaining samples for measurement via laboratory methodology or point of care devices and require invasive collection techniques such as capillary stick, venipuncture, or the placement of intravenous catheters. Limitations of traditional methods include the limited information provided by intermittent testing and the stress associated with restraint and discomfort experienced by patients. The snapshot nature of the provided information restricts a clinician's ability to truly monitor trends in glucose concentrations over an extended period of time, influencing clinical decision making. The stress of invasive sampling can cause stress hyperglycemia in many veterinary species, complicating interpretation. Continuous interstitial glucose monitoring technology is widely used in the human medical field due to the expansive information provided in a minimally invasive manner. In recent years, the device technology has advanced and cost has improved, prompting application of these devices into the veterinary sector. Studies have shown good agreement between newer glucose monitoring systems and traditional methods in small animal patients with diabetes mellitus, allowing veterinarians to obtain comprehensive glucose data with minimal stress and discomfort to the patient. However, information regarding the use of this new technology in equine medicine is limited. The following study describes the evaluation of two widely available glucose monitoring systems, the Dexcom G6 and the FreeStyle Libre, in healthy adult horses. / Master of Science / Monitoring of glucose concentrations is essential for the diagnosis and monitoring of a variety of disorders within equine medicine. Traditional methods of obtaining samples for testing include capillary stick, venipuncture, or the placement of intravenous catheters, which can cause stress and discomfort to equine patients. The information obtained by this testing methodology only allows for intermittent assessment of glucose concentrations, limiting the amount of information available for clinicians to make clinical decisions. The use of continuous glucose monitoring systems in the human medical field have allowed clinicians to obtain continuous or near-continuous glucose concentrations, improving interpretation. These devices have nearly eliminated the need for blood sampling for glucose concentrations, instead relying on interstitial glucose concentrations which have been shown to compare favorably to blood concentrations. Studies in small animal veterinary species, such as dogs and cats, have shown good agreement between newer glucose monitoring systems and traditional methods in small animal patients with diabetes mellitus, allowing veterinarians to obtain comprehensive glucose data with minimal stress and discomfort to the patient. However, information regarding the use of this new technology in horses is limited. The study described in the manuscript following evaluates the use of two widely available glucose monitoring systems, the Dexcom G6 and the FreeStyle Libre, in healthy adult horse.

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