University of Macau / Faculty of Social Sciences. / Department of Communication

Orientador: Ana Angélica Henrique Fernandes / Resumo: Diabetes mellitus (DM) é uma desordem metabólica caracterizada pela hiperglicemia persistente, com distúrbios no metabolismo de carboidratos, lipídios e proteínas, resultante de defeitos na secreção de insulina, ação da insulina ou ambos. A utilização de antioxidantes tem contribuído para melhorar a hiperglicemia e também minimizar as complicações diabéticas. Geraniol, um monoterpeno, presente na composição de óleos essenciais de várias plantas medicinais, apresenta ação antioxidante e antihiperglicemiante, sendo capaz de contribuir na terapêutica desta patologia. Este estudo tem como objetivo avaliar o metabolismo energético e estresse oxidativo no miocárdio de ratos com DM tipo 1, tratados com geraniol. Foram utilizados 32 ratos machos, Wistar (± 250g de peso corporal), distribuídos em 4 grupos experimentais (n=8): C (normais, controle); GE (normais, tratados com geraniol); DM (diabéticos, não-tratados); DM-GE (diabéticos, tratados com geraniol). A DM tipo 1 experimental foi induzido através da administração de estreptozotocina (STZ – 60 mg/Kg de peso corporal, i.p., dose única). Os animais dos grupos GE e DM-GE receberam geraniol (200 mg/Kg/dia) via gavagem durante 30 dias e os animais dos grupos C e DM receberam água pelo mesmo procedimento. Durante o período experimental, foram avaliados consumo de água e ração. Após este período, os animais em jejum de 12 horas, foram anestesiados (xilazina e cetamina) e eutanasiados. Foram coletadas amostras séricas para análise da con... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Diabetes mellitus (DM) is a metabolic disease characterized by persistent hyperglycemia, with disorders in the metabolism of carbohydrates, lipids and proteins, resulting from defects in insulin secretion, insulin action, or both. The use of antioxidants has contributed to improve hyperglycemia and also minimize diabetic complications. Geraniol, a monoterpene, present in the composition of essential oil of various medicinal plants, has oxidant and antihyperglycemic action, being able to contribute in the therapy of this pathology. This study aimed to evaluate the energetic metabolism and oxidative stress in the myocardium of rats with type 1 DM treated with geraniol. 32 male Wistar rats (±250g body weigth), distributed in four experimental groups (n=8): C (normal, control); GE (normal, treated with geraniol); DM (diabetic, untreated); DM-GE (diabetic, treated with geraniol). Experimental type 1 DM was induced by streptozotocin (STZ - 60mg/Kg body weight, i.p., single dose). Animals of the group GE and DM-GE received geraniol (200mg/K/day) by gavage for 30 days and animals of the group C and DM received water by the same procedure. Animals of the group GE and DM-GE received geraniol (200mg/K/day) by gavage for 30 days and animals of the group C and DM received water by the same procedure. During the experimental period, food and water intake were evaluated. After this period the animals, in a 12h fast, were anesthetized and euthanized. Serum samples were collected for glycemia... (Complete abstract click electronic access below) / Doutor

Reperfusion of the isolated rat heart following 10 min of coronary artery ligation under constant flow conditions results in the development of arrhythmias - premature ventricular contractions (PVCs), ventricular tachycardia (VT) and ventricular fibrillation (VF). Increasing concentrations of magnesium (0 - 4.8 mM) and/or potassium (2.5 - 10.0 mM) attenuate, while calcium (0.6 - 2.4 mM) exacerbates these arrhythmias. The protective effects of magnesium and potassium were additive. Magnesium reduced heart rate, perfusion pressure and developed tension. Potassium reduced perfusion pressure and increased developed tension. These haemodynamic effects contributed to the antiarrhythmic action of magnesium but did not completely account for its antiarrhythmic action. Calcium increased developed tension and heart rate and reduced perfusion pressure. Post-ligation administration of magnesium and potassium also protected against reperfusion arrhythmias. These results demonstrate that reperfusion arrhythmias are significantly affected by the ionic environments of the heart. Superoxide dismutase (5 - 20 Um1-1 ), glutathione (10 -5 - 10-3M), ascorbic acid (10-4 -5 x 10-4 M) and histidine (5 x 10-3 M) when given before coronary artery ligation attenuated the development of reperfusion arrhythmias. Mannitol (2 x 10-2 M) and catalase (100 - 300 Uml-1) did not have any significant effect on reperfusion arrhythmias when given alone but they did potentiate the effect of superoxide dismutase. Glutathione and a combination of superoxide dismutase, catalase and mannitol also reduced the incidence of reperfusion induced ventricular fibrillation when given just before reperfusion. Ferrous ion exacerbated the severity of reperfusion arrhythmias. Mannitol (2 x 10-2 M), catalase (100 uml-1) and histidine (5 x 10-3 M) when given before coronary ligation or just before reperfusion prevented the effect of ferrous ion while superoxide dismutase did not, indicating that the presence of ferrous ion is important for the production of hydroxyl radicals. Pretreatment with 6- OHDA attenuated the incidence of reperfusion arrhythmias but pre-ligation administration of allopurinol had no effect on reperfusion arrhythmias. By perfusing hearts with ferricytochrome C it was possible to show an increased reduction of ferricytochrome C during the first minute of reperfusion which could be prevented by the addition of superoxide dismutase and 6-OHDA treatment. These results provide evidence that oxygen free radicals are produced and may be important in the genesis of reperfusion induced arrhythmias in the isolated rat heart. Adenosine (10-6 M), verapamil (10 -8 - 10-7 M), ZK 36374 (10-10 - 10 -9 M) and sodium nitroprusside (10-6 -10-9 M) attenuate the incidence of reperfusion arrhythmias which may be via a coronary steal effect. Agents which affect arachidonic acid metabolism yielded conflicting results which may reflect nonspecific mechanisms other than inhibition of arachidonic acid metabolism. Glutathione and a mixture of superoxide dismutase, catalase and mannitol when given before coronary ligation and just before reperfusion reduced the increase in 86 rubidium efflux rate constant shown on reperfusion. The effect of glutathione on 86 rubidium efflux may be at least in part due to its vasodilator effect. Superoxide generation by xanthine/xanthine oxidase system increased the rate of efflux of 86 rubidium. A mixture of superoxide dismutase, catalase and mannitol also reduced the transient increase in the rate of release of 3H-noradrenaline shown to be produced on reperfusion after 10 min of ischaemia in the isolated rat heart.

The importance of oral health on systemic health is a highly researched area of study in recent years. There has been a shift in dental visits from acute emergencies to ongoing preventative care due to the knowledge connecting oral and systemic health. One of the commonly researched connections is the link between periodontal disease and heart disease. Periodontal disease is defined as inflammation of the gum tissue, resulting in periodontal pockets that can lead to infection, bone loss and even loss of the tooth. Cardiovascular disease, or heart disease, is a term that encompasses many different conditions of the heart, including heart failure, myocardial infarction, atherosclerosis and angina. There is constant research to better understand the relationship between the two diseases, as well as any causality that may exist. Recent studies have been able to link the diseases, but no causal link has been found. The role of the bacteria involved in both diseases has recently been considered to see if these organisms are related to a potential causal link. Two particular bacteria that are known to be involved with periodontal disease are Porphyromona gingivalis and Treponema denticola. These bacteria are present when a patient develops periodontal disease, but they are not usually present in a healthy individual. Additionally, the bacteria that make up the contents of plaque found in the heart have been studied to see if there are any similarities with oral microbes. It has been found that oral bacteria can be present in arterial plaque samples. This research may allow a better understanding of how and why heart disease occurs and potentially serve as a way to treat heart disease accompanied by periodontal disease, if a causal relationship is elucidated. Heart disease is usually a devastating disease, sometimes resulting in the death of the patient. If more patients attend the dentist as a preventative measure, the risk of periodontal disease and associated pathologies may be reduced. Additionally, those that have already developed periodontal disease can work with a dental professional to reverse the disease. It is known that the bacteria in the mouth can enter the bloodstream upon infection, so patients with suspected periodontitis should be treated to avoid the bacteria from entering the blood and affecting other organs such as the heart. An examination of the bacteria commonly found in the oral cavity at times of periodontal disease may lead to a better understanding of how and why these bacteria invade the bloodstream. It would be beneficial to compare the microbiota of both the plaque in the mouth and the plaque in a vessel supplying the heart in a patient suffers from heart disease. This understanding may lead to therapeutic interventions that aid in the prevention of bacteria traveling in the bloodstream. For many Americans, oral health care was believed to end at home by brushing and flossing. However, it is important to see a dental professional to avoid any possible complications that may not be apparent to the untrained eye. A simple dental cleaning may be important to detect the start of periodontal disease, and treatment can be initiated to end the potential spread of bacteria. It is important to maintain positive oral health in order to maintain overall systemic health, including the avoidance of heart disease.

Aim: To explore parents’ experiences of the transition from hospital to home with their infant, following first stage cardiac surgery for a functionally univentricular heart or systemic shunt dependent cardiac lesion. Background: The process of monitoring a fragile infant at home, in between stage 1 and 2 of cardiac surgery, takes the philosophical perspective of holistic care beyond the borders and boundaries normally expected of parents going home for the first time with their new baby. This neo-transition of becoming a medical parent is superimposed upon the multiple transitions already experienced during the birth and whilst in hospital (new baby, new to parenthood, sick baby, cardiac surgery, ongoing and lifelong care needs). The impact of these transitions, on parents’ wellbeing and the influence of parents’ demographics on their ability to effectively monitor their infant at home, has not previously been studied. Methods: A mixed methods study was conducted in two phases. Phase one was a retrospective survey of 22 families (35% response rate). Phase two prospectively explored parents’ experiences using semi-structured interviews and 3 self-report tools to assess anxiety, depression and confidence; with 13 mothers and 4 fathers of 13 infants. The qualitative data was thematically analysed; descriptive analysis of the quantitative data was undertaken using the Statistical Package for the Social Sciences (IBM SPSS Inc.) version 22 for Windows Results: Most parents felt unprepared for their infant’s discharge home; numerous physical, emotional and social boundaries and borders were evident during the transition from hospital to home, which impacted upon parents’ knowledge and preparedness. Traversing the physical boundary of leaving the hospital for the first time with their infant, was loaded with emotionally traumatic experiences that could not be separated from the specific physical transition of going home. For a while parents were in an uncertain place where they could not visualise what was ahead and how it would feel. This created anxiety and fear, at the same time as excitement to be going home. Liminality as a concept emerged during transition from hospital to home; a crossing point from a comfort zone, safety and security (the ward) into the unknown uncertain place (home). Adjusting to the situation; developing confidence; becoming comfortable with new skills was a threshold concept to mastery of a new normal. Conclusion: Discharge strategies need to be more consistent locally and nationally to ensure that parents are prepared physically, psychologically and socially for discharge home with their infant. Local and community health care professionals need to be better prepared to effectively support these infants and their parents at home.

Heart failure (HF) is a common cause of hospitalisation and mortality across industrialised countries. The number of hospitalisations and deaths attributed to heart failure is increasing, and this trend is predicted to continue. Numerical and in-vitro simulations of the human cardiovascular system constitute the basic tools for enhancing diagnostic and therapeutic technologies for HF and this would in turn, have significant effects on morbidity,mortality, and healthcare expenditure. Mechanical Circulatory Support (MCS) as a destination therapy for HF is rising significantly as it provides a cost-effective alternative to long-term treatment and cardiac transplantation. However, long-term versatility is far from ideal and incidence of transient and permanent neurological events is still high. To this end, evolution of MCS devices calls for more sophisticated design and evaluation methods. The purpose of this work is to develop a numerical model and to implemented a novel in-vitro model of the cardiovascular system with the intention of evaluating the performance characteristics of a purposely selected centrifugal pump impeller for the treatment of both Class III and IV HF conditions when placed in series with the heart at two different anatomic locations: Ascending Aorta and Descending Aorta. An existing lumped-parameter model of the CV system, that included models for the heart, the pulmonary and the systemic circulatory loops by adapting a modified version of the fourth-element Windkessel model was enhanced by dividing the systemic circulation into six parallel vascular beds, and by including an autoregulatory system to control both pressures and volumes throughout the system. As part of the novelty of the present work, a volume reflex loop was included with the purpose of simulating volume overload conditions, as commonly found in HF conditions, and obtaining a more realistic analysis of volume displacement, while using a MCS device. The in-vitro model implemented in this work adopted most of the features included in the mathematical counterpart with the purpose of validating the numerical results. As a result of the combination of models and proper optimisation of the system parameters, predictions of pathophysiological trends and MCS usage are satisfactorily obtained. The models implemented in this work offer a valuable tool for the selection and performance evaluation of MCS devices for the treatment of HF conditions.

by Kwok-keung Chan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 177-195). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Cardiac arrhythmias are caused by disordered propagation of electrical activity. Progress in understanding and controlling arrhythmias requires novel methods to characterize and control the spatiotemporal propagation of electrical activity. We used patterned illumination of cardiomyocytes derived from optogenetic human induced pluripotent stem cells to create dynamic conduction blocks, and to test spatially extended control schemes. Using this model, we demonstrated the ability to initiate, circumscribe, relocate, and terminate pathologic spiral waves that drive many arrhythmias. When cells were derived from patients with long QT syndrome, longer action potential durations made spiral waves more resistant to termination. This work lays the foundation for personalized models of cardiac injury and disease, and the development of tailored approaches to the management of arrhythmias.

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