78 resultados para hepatic health
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The development of human cell models that recapitulate hepatic functionality allows the study of metabolic pathways involved in toxicity and disease. The increased biological relevance, cost-effectiveness and high-throughput of cell models can contribute to increase the efficiency of drug development in the pharmaceutical industry. Recapitulation of liver functionality in vitro requires the development of advanced culture strategies to mimic in vivo complexity, such as 3D culture, co-cultures or biomaterials. However, complex 3D models are typically associated with poor robustness, limited scalability and compatibility with screening methods. In this work, several strategies were used to develop highly functional and reproducible spheroid-based in vitro models of human hepatocytes and HepaRG cells using stirred culture systems. In chapter 2, the isolation of human hepatocytes from resected liver tissue was implemented and a liver tissue perfusion method was optimized towards the improvement of hepatocyte isolation and aggregation efficiency, resulting in an isolation protocol compatible with 3D culture. In chapter 3, human hepatocytes were co-cultivated with mesenchymal stem cells (MSC) and the phenotype of both cell types was characterized, showing that MSC acquire a supportive stromal function and hepatocytes retain differentiated hepatic functions, stability of drug metabolism enzymes and higher viability in co-cultures. In chapter 4, a 3D alginate microencapsulation strategy for the differentiation of HepaRG cells was evaluated and compared with the standard 2D DMSO-dependent differentiation, yielding higher differentiation efficiency, comparable levels of drug metabolism activity and significantly improved biosynthetic activity. The work developed in this thesis provides novel strategies for 3D culture of human hepatic cell models, which are reproducible, scalable and compatible with screening platforms. The phenotypic and functional characterization of the in vitro systems performed contributes to the state of the art of human hepatic cell models and can be applied to the improvement of pre-clinical drug development efficiency of the process, model disease and ultimately, development of cell-based therapeutic strategies for liver failure.
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In this study we aim to investigate the health discrepancies arising from unequal economic status, known as the “wealth-health gradient”. Our sample comprises 47,163 individuals from 14 European countries in the SHARE Wave 4 (2011), representing the population aged 50 and older. Through a cross-sectional OLS regression model, we have tested the impact of country-level indicators to infer their effect on personal health and on the magnitude of the gradient. The results find that private expenditure yields, on average, a higher, but fast decreasing, health benefit than public expenditure; and that income inequality is irrelevant for reducing health inequalities.
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RESUMO: Raional: A persistência à terapêutica é o tempo em qualquer antidiabético oral, desde o seu início até à descontinuação de todas as medicações ou até ao fim do período do estudo. Os objetivos deste estudo foi a análise da persistência à terapêutica no segundo e terceiro anos após início do tratamento em doentes adultos diagnosticados na região de Lisboa e Vale do Tejo e determinar o efeito de determinadas variáveis na persistência a longo prazo. Métodos: Um estudo retrospetivo não interventivo foi desenhado com base nos dados a obter do SIARS (prescrições e aquisições na farmácia) e Pordata. A persistência foi quantificada como a percentagem de doentes que continuam a adquirir pelo menos um antidiabético oral ao segundo e terceiro anos após a compra da primeira receita. A associação entre a persistência e o segundo e terceiro anos com cada uma das co-variáveis foi aferido pelo teste qui-quadrado e os odd ratios foram calculados com recurso a um modelo de regressão logística. Resultados: A persistência à terapêutica obtida foi de 80% e 62% para o segundo e terceiro anos após início da terapêutica. Odd ratios para primeiro e segundo ano: número de grupos farmacoterapêuticos diferentes (OR = 2.167, 1.807 – 2.598, p = 0.000 / OR = 1.863, 1.621 – 2.142, p = 0.000); idade (OR = 0.914, 0.772 – 1.081, p = 0.294 / OR = 0.875, 0.764 – 1.002, p = 0.054); sexo (OR = 1.163, 0.983 – 1.377, p = 0.079); número de diferentes prescritores (OR = 3.594, 3.030 – 4.262, p = 0.000 / OR = 2.167, 1.886 – 2.491, p = 0.000); instituição de prescrição (OR = 0.725, 0.698 – 0.753, p = 0.000 / OR = 0.683, 0.650 – 0.717, p = 0.000); grupo farmacoterapêutico (OR = 1.056, 1.043 – 1.069, p = 0.000 / OR = 1.077, 1.060 – 1.095, p = 0.000); relação com o médico (OR = 0.834, 0.816 – 0.852, p = 0.000 / OR = 0.799, 0.777 – 0.821, p = 0.000) e custo médio mensal por grupo farmacoterapêutico (OR = 0.954, 0.942 – 0.968, p = 0.000 / OR = 0.930, 0.914 – 0.947, p = 0.000). Conclusões: O valor da persistência à terapêutica no segundo ano é ligeiramente acima do que é mencionado na literatura e não existem dados para comparar os resultados do terceiro ano. Relativamente ao efeito das co-variáveis no segundo e terceiro anos após o início do tratamento, os resultados são sobreponíveis, sendo que o sexo não está associado à persistência ao terceiro ano.----------------------------------ABSTRACT: Background: Therapy persistence is the time on any antidiabetic medication, from initiation of therapy to discontinuation of all medications or the end of the study period. The aim of the study was to analyse the therapy persistence in the second and third years after treatment initiation in newly diagnosed adult patients in the Lisbon and Tagus Valley region and to determine the effect of several co-variables in the long term persistence. Methods: A retrospective non-interventional study based on SIARS data (drug prescriptions and acquisitions) and Pordata was designed. Persistence was quantified as the percentage of patients that continued to purchase at least one type of antidiabetic at year 2 and 3 after the date of first prescription acquisition. Association between persistence at second and third years with each of the other co-variables were verified by using the Chi-Square test and odds ratio were calculated using a regression logistic model. Results: Therapy persistence obtained was 80% and 62% for the second and third years after treatment initiation. Odd ratios for second and third years: number of different pharmacotherapeutic groups (OR = 2.167, 1.807 – 2.598, p = 0.000 / OR = 1.863, 1.621 – 2.142, p = 0.000); age (OR = 0.914, 0.772 – 1.081, p = 0.294 / OR = 0.875, 0.764 – 1.002, p = 0.054); gender (OR = 1.163, 0.983 – 1.377, p = 0.079); number of different prescribers (OR = 3.594, 3.030 – 4.262, p = 0.000 / OR = 2.167, 1.886 – 2.491, p = 0.000); institution of prescription (OR = 0.725, 0.698 – 0.753, p = 0.000 / OR = 0.683, 0.650 – 0.717, p = 0.000); pharmacotherapeutic group (OR = 1.056, 1.043 – 1.069, p = 0.000 / OR = 1.077, 1.060 – 1.095, p = 0.000); relationship with the physician (OR = 0.834, 0.816 – 0.852, p = 0.000 / OR = 0.799, 0.777 – 0.821, p = 0.000) and average cost per month and per pharmacotherapeutic group (OR = 0.954, 0.942 – 0.968, p = 0.000 / OR = 0.930, 0.914 – 0.947, p = 0.000). Conclusions: Second year therapy persistence value is slightly above of what is referenced in literature and no data was found to compare the third year value. Regarding the effect of the co-variables analysed at second and third years after treatment initiation, the results were overlapping with gender being not associated with persistence at the third year.
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Evidence in the literature suggests a negative relationship between volume of medical procedures and mortality rates in the health care sector. In general, high-volume hospitals appear to achieve lower mortality rates, although considerable variation exists. However, most studies focus on US hospitals, which face different incentives than hospitals in a National Health Service (NHS). In order to add to the literature, this study aims to understand what happens in a NHS. Results reveal a statistically significant correlation between volume of procedures and better outcomes for the following medical procedures: cerebral infarction, respiratory infections, circulatory disorders with AMI, bowel procedures, cirrhosis, and hip and femur procedures. The effect is explained with the practice-makes-perfect hypothesis through static effects of scale with little evidence of learning-by-doing. The centralization of those medical procedures is recommended given that this policy would save a considerable number of lives (reduction of 12% in deaths for cerebral infarction).
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Despite the fact that public medical care has being heavily subsidized through a statutory national health system there has been a growing number of people who opt to enroll in extra private coverage. Using a two part model to infer the insurance decision and subsequent amount of insurance chosen we found out that people’s decision over private health coverage is not related with their health. The pattern of consumption of medical care that is not available in the public sector and a good socio economic background were found significant modeling the demand for private health insurance.
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Primary health services exist with the purpose of providing basic health care to every person at a cost they can afford. But is it fully available to everyone? The objective of this work project is to estimate the demand for primary health care services having into account that in some regions the citizens are not using as much health care as they would like due to supply side constraints. Using the number of consultations as proxy for demand, and applying an econometric tool called switching regression, the demand for primary health care services will be estimated.
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Mental health awareness has been rising worldwide, motivated by its social and economic costs. Despite the investment in research in neuroscience in the recent years, little is known about the underlying mechanisms in the brain that are correlated with psychiatric conditions. This project, through two feature articles suitable to be published in magazines, provides perspectives onto mental health research. First it presents an example where psychiatry joins forces with neuroscience and computer science in an interdisciplinary effort to improve the life of those affected by mental disorders. The second article gathers opinions which claim that mental health research priorities should be set by patients themselves, or even that people with lived experience of mental health issues should have an active role in that research. This project was planned and researched while I was an Erasmus student at Nottingham Trent University, in the United Kingdom.
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ABSTRACT: Background: Childhood is a critical time for social and emotional development, educational progress and mental health prevention. Mental health for children and adolescents is defined by the achievement of expected developmental, cognitive, social and emotional skills. The development of child-adolescent mental health services (CAMHS) is a necessity for each country, not only as a prevention measure for the wellbeing of people, but also as an investment to the future of countries. Qualitative evaluation of services is the only way to ensure whether services function under quality standards and increase the possibility of better outcomes for their patients. This study examines the greek outpatient CAMHS against the British Standards of National Institute of Excellence for community CAMHS. The Standards assessed refer to the areas of Assessment, Care and Intervention. Objectives: The main objectives of the study are 1) to evaluate Greek outpatient CAMHS in the Attica region 2) to promote the evaluation process for mental health services in Greece. Methods: Due to the fact that Greek services are based on the British model, the tool used was the British self-review questionnaire of Quality Network for Community CAMHS(QNCC).The tool was translated, adapted and posted to services. Twelve out of twenty outpatient CAMHS of Attica (including Athens) responded. Data was collected and performed by the Statistical Package for Social Sciences SPSS. Results: The study resulted that the CAMHS examined, meet moderately the British Standards of 1) Referral and Access, 2) Assessment & Care planning, 3) Care & Intervention. Two out of twelve services examined, meet the standards of "Assessment and Care" in a higher percentage between 75% and 100%. Conclusions: The paper describes a satisfactory function of CAMHS in Attica prefecture taking into consideration the extremely difficult political situation of Greece at the time of the research. Strong and weak domains are identified. Also the translation and adaptation of British tools promote the evaluation process and quality assurance of Greek CAMHS.
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RESUMO: O Ministério da Saúde do Governo do Ruanda identifica a saúde mental como uma área de prioridade estratégica para a intervenção em resposta à alta carga dos transtornos mentais no Ruanda. Ao longo dos últimos 20 anos após o genocídio, o sector público reconstruiu sua Resposta Nacional de Saúde Mental com base no acesso equitativo aos cuidados, através do desenvolvimento de uma Política Nacional de Saúde Mental e novas estruturas de saúde mental. A política de Saúde Mental do Ruanda, revista em 2010, prima pela descentralização e integração dos serviços de saúde mental em todas as estruturas nacionais do sistema de saúde e ao nível da comunidade. O presente estudo de caso tem como objetivo avaliar a situação do sistema de saúde mental de um distrito típico de uma área rural no Ruanda, e sugerir melhorias, incluindo algumas estratégias para monitoras as mudanças. Os resultados do estudo permitirão ao Ruanda reforçar a sua capacidade para implementar o Plano Nacional de Saúde Mental ao nível dos distritos. O relatório também será útil para monitorar o progresso da implementação de serviços de saúde mental nos distritos, incluindo a prestação de serviços de base comunitária e a participação dos usuários, suas famílias e outros interessados na promoção, prevenção, assistência e reabilitação em saúde mental. Este estudo também procurou avaliar o progresso da implementação dos cuidados de saúde mental a nível descentralizado, com vista a compreender as implicações em termos de recursos desses processos. Foi realizada uma análise situacional num local do distrito, baseado em entrevistas com as principais partes interessadas responsáveis, usando o Instrumento de Avaliação de Sistemas de Saúde Mental da Organização Mundial da Saúde (WHO-AIMS). Os resultados sugerem que os recursos humanos para a saúde mental e serviços de base comunitária de saúde mental no distrito continuam a ser extremamente limitados. Os profissionais de saúde mental são adicionalmente limitados na sua capacidade para oferecer intervenções de emergência a pacientes psiquiátricos e garantir a continuidade do tratamento farmacológico a pacientes com condições crônicas. Para planejar efetivamente, de acordo com as necessidades da comunidade, sugerimos que o sistema de saúde mental deve envolver também os representantes das famílias e dos usuários no processo de planificação de modo a melhorar a sua contribuição no processo de implementação das atividades de saúde mental. Este estudo de caso do Distrito de Bugesera oferece a primeira análise de nível distrital dos serviços de saúde mental no Ruanda, e pode servir como uma mais-valia para a melhoria do sistema de saúde mental, incluindo a advocacia para a melhoria da qualidade dos cuidados de saúde mental a este nível, aumentando o financiamento para a implementação de serviços clínicos de saúde mental e os recursos humanos disponíveis para a prestação de cuidados de saúde mental, principalmente a nível dos cuidados primários.--------------------- ABSTRACT: To deal with the high burden of mental health disorders resulting from consequences of the 1994 genocide against Tutsis, the Rwanda Ministry of Health (MoH) considers mental health as a priority intervention. For the last 20 years, Ministry of Health focused on rebuilding a national and equity-oriented mental health program responding to the population needs in mental health. Mental health services are now decentralized and integrated in the national health system, from the community level up to the referral level. This study assessed the situation of mental health services in one rural district in Rwanda. It was aimed at assessing the progress of implementation of mental health care at the decentralized level, focusing on resource implications and processes. This study is based on interviews conducted with key stakeholders, using the World Health Organization's Assessment Instrument for Mental Health Systems (WHO-AIMS). Findings show that human resources for mental health care and community-based mental health services of the assessed district remain extremely limited. Mental health professionals face limitation regarding the ability to provide emergency management of psychiatric patients and to ensure continuity of psychopharmacological treatment of patients with chronic conditions. To improve the implementation process of mental health interventions and activities, a planning process based on community needs and the involvement of representatives of families and users in planning process should be considered. The Bugesera case study on the situation of mental health services can serve as a baseline for improvement of the mental health program in Rwanda, in terms of quality care services, infrastructure and equipment, human and financial resources.
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RESUMO: O Royal College of Psychiatrists tem um programa de voluntariado internacional desde 2005. O interesse no Reino Unido tem crescido nos últimos 15 anos com muitos projetos novos. Os benefícios para vários países têm sido reconhecidos. O que está menos claro são os benefícios da experiência para o Reino Unido e do programa de voluntariado do Royal College of Psychiatrists. O objectivo desta dissertação é explorar os benefícios do voluntariado para o Sistema Nacional de Saúde focando principalmente, mas não exclusivamente, o programa de voluntariado do Royal College of Psychiatrists. Nesta dissertação abordamos primeiro o contexto antes de discutirmos dois grandes estudos de psiquiatras e hospitais do Sistema Nacional de Saúde no Reino Unido. Incluimos no estudo todos os psiquiatras registados como Voluntários no Royal College of Psychiatrists e o Grupo de Interesse Especial associado. Foi ainda possível incluir os Diretores Médicos de todos os hospitais do Reino Unido. Os estudos foram desenhados para analisar as opiniões dos Voluntários do Reino Unido sobre os benefícios para os países recetores de baixo e médio rendimento e para o Reino Unido. Todos os 60 hospitais do Sistema Nacional de Saúde foram incluí dos para analisar a opinião sobre Voluntariado. As limitações dos estudos foram a baixa taxa de resposta, mas esta foi comparável a outros estudos do College. É provável haver um enviezamento de resposta e favorecimento dos que estão envolvidos no Voluntariado. Os resultados mostraram um interesse forte no voluntariado e benefícios no Sistema Nacional de Saúde, nas. áreas de liderança, transculturalismo, gestão e recursos e capacidades pessoais. Os hospitais do Sistema Nacional de Saúde valorizaram o voluntariado e, em contrapartida, o valor acrescido para competências profissionais. Os obstáculos contra o Voluntariado a nível individual e dos hospitais foram maioritariamente de natureza prática, tais como obter dispensa do trabalho, substituição no trabalho e custos. As implicações destes estudos são que o programa de voluntariado do College precisa de ser fortalecido. Para assegurar que este trabalho continua é necessário existir uma sensibilização nacional e maior responsabilização sobre os benefícios para o Reino Unido e a nível global. -------------------------- ABSTRACT: The Royal College of Psychiatrists has had an international volunteering programme since 2005. The interest in UK has grown over the past 15 years with many new projects. The benefits in various countries has been acknowledged. What has been less clear are the benefits of the experience back in the UK and of the Royal College of Psychiatrists Volunteer Scheme. The aim of this dissertation is to explore the benefit of volunteering to the NHS focusing mainly, but not exclusively on the Royal College of Psychiatrists Volunteering scheme. In this dissertation we first look at background information before discussing two large surveys of Psychiatrists and NHS Trusts in UK. We surveyed all those registered as Volunteers at the Royal College of Psychiatrists and the associated Special Interest Group. We also were able to survey the Medical Directors of all UK Trusts. The Surveys were designed to assess views of UK Volunteers of benefits to hosts in LMIC and back in UK. All 60 NHS Trusts were surveyed to assess the view of Volunteering. Limitation of the surveys were the low response rate but this was comparable to other College surveys. There is likely to be a bias in response and favour those who are engaged in the Volunteering agenda. Results showed a strong interest in volunteering and perceived benefits in NHS. These areas included leadership, transcultural, resource management and personal skills. NHS trusts valued volunteering and added value to professional competencies on return. Obstacles to Volunteering at individual and Trust level were mainly practical issues such as getting time off, cover and costs. Implications of these surveys are that the College volunteering scheme needs strengthening. There needs to be a National advocacy to ensure that this work continues and greater accountability as to benefits in UK and globally.
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ABSTRACT - Objectives: We attempted to show how the implementation of the key elements of the World Health Organization Patient Safety Curriculum Guide Multi-professional Edition in an undergraduate curriculum affected the knowledge, skills, and attitudes towards patient safety in a graduate entry Portuguese Medical School. Methods: After receiving formal recognition by the WHO as a Complementary Test Site and approval of the organizational ethics committee , the validated pre-course questionnaires measuring the knowledge, skills, and attitudes to patient safety were administered to the 2nd and3rd year students pursuing a four-year course (N = 46). The key modules of the curriculum were implemented over the academic year by employing a variety of learning strategies including expert lecturers, small group problem-based teaching sessions, and Simulation Laboratory sessions. The identical questionnaires were then administered and the impact was measured. The Curriculum Guide was evaluated as a health education tool in this context. Results: A significant number of the respondents, 47 % (n = 22), reported having received some form of prior patient safety training. The effect on Patient Safety Knowledge was assessed by using the percentage of correct pre- and post-course answers to construct 2 × 2 contingency tables and by applying Fishers’ test (two-tailed). No significant differences were detected (p < 0.05). To assess the effect of the intervention on Patient Safety skills and attitudes, the mean and standard deviation were calculated for the pre and post-course responses, and independent samples were subjected to Mann-Whitney’s test. The attitudinal survey indicated a very high baseline incidence of desirable attitudes and skills toward patient safety. Significant changes were detected (p < 0.05) regarding what should happen if an error is made (p = 0.016), the role of healthcare organizations in error reporting (p = 0.006), and the extent of medical error (p = 0.005). Conclusions: The implementation of selected modules of the WHO Patient Safety Curriculum was associated with a number of positive changes regarding patient safety skills and attitudes, with a baseline incidence of highly desirable patient safety attitudes, but no measureable change on the patient safety knowledge, at the University of Algarve Medical School. The significance of these results is discussed along with implications and suggestions for future research.
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This study investigates three questions related to medical practice variation. First, it tests whether average length of stay across Portuguese National Health Service hospitals varies when controlling for differences in patients’ characteristics. Second, it looks at hospital-level characteristics in order to find out whether these are able to explain differences in average length of stay across hospitals. Finally, it proposes a best practice average length of stay for each of the six episodes of care analyzed. To perform the analysis, administrative data from the Diagnosis-Related groups’ data set for the year of 2012 was used. A replication of a hierarchical two-stage model with hospital fixed effects was carried out. The results show that after taking patients’ characteristics into account, variation in average length of stay across hospitals exists. This variation cannot be explained by hospital-level characteristics.
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RESUMO: Objetivo Avaliar a qualidade dos serviços de saúde mental e a situação dos direitos humanos no Hospital de Saúde Mental de Kabul (KMHH) e fornecer recomendações para o desenvolvimento de um plano de melhoria, actualização e revisão da Política, Estratégia e Plano Nacionais de Saúde Mental,. Métodos A avaliação foi realizada em Janeiro de 2015 no KMHH e na Burn Ward do Hospital Terciário de Isteqlal por uma equipa multidisciplinar usando Qualidade Direitos Tool Kit da OMS. Antes da avaliação, o protocolo foi aprovado pelo Institutional Review Board e obtido o consentimento informado de cada entrevistado. Realizaram-se entrevistas com 16 utentes do serviço, 17 funcionários do hospital e 7 familiares, além da revisão de documentos e da observação das unidades de internamento do KMHH e das interações interpessoais entre funcionários do hospital e utentes do serviço. A comissão de avaliação reviu também a documentação e observou a Unidade de Queimados do Hospital Terciário de Isteqlal, a fim de avaliar e comparar a paridade entre as duas instalações. Após a avaliação, todos os membros da comissão se reuniram e puseram em conjunto todas as conclusões num relatório final. Resultados Encontrámos algumas lacunas graves no nível de prestação de serviços e no respeito pelos direitos humanos dos utentes dos serviços e dos seus familiares. Uma série de políticas, diretrizes e procedimentos relacionados com os direitos humanos dos pacientes estavam ausentes. O ambiente terapêutico e o padrão de vida eram inadequados, existia má qualidade do atendimento e dos serviços prestados, os utilizadores enfrentavam violações do direito ao exercício da capacidade legal e da liberdade pessoal, eram quimica e fisicamente (uso de correntes) contidos e expostos a abusos verbais, físicos e emocionais, e havia grande ênfase no tratamento institucional. Todos estes aspectos foram considerados como extensa violação dos direitos humanos dos utentes de serviço do KMHH. Conclusão Os serviços disponíveis para utentes dos serviços de saúde mental apresentam alguns problemas devido à desconfiança e falta de consciencialização sobre os direitos das pessoas com doença mental e precisam ser alterados de forma positiva. A Lei de Saúde Mental existente difere muito das recomendações da Convenção sobre os Direitos das Pessoas com Incapacidades (CRPD) e requer revisão e adaptação de acordo com esta Convenção. -------------------------------- ABSTRACT: Objective To assess the quality of mental health services and human rights condition in the Kabul Mental Health Hospital (KMHH) and provide recommendations for development of an improvement plan and to update and revise the National Mental Health Policy, Strategy and Plan. Methods The assessment was conducted in January 2015 in the KMHH and the Burn Ward of Isteqlal Tertiary Hospital by a multidisciplinary team using WHO Quality Rights Tool Kit. Before the assessment, Institutional Review Board approval and informed consent from each interviewee were obtained. Interviews were conducted with 16 service users, 17 hospital staffs and 7 family members in addition to documents review and observation of inpatient units of KMHH plus interpersonal interactions between hospital staff and service users. The assessment committee reviewed the documentation and observed the Burn Ward of Isteqlal Tertiary hospital in order to measure and compare parity between the two facilities. After the assessment, all committee members gathered and synchronized all findings into a final report. Results There were some serious gaps on service provision level and respecting human rights of service users and their family members. A series of policies, guidelines and procedures related to patients’ human rights were absent. Inadequate treatment environment and standard of living, poor quality of care and services, violations of the right to exercise legal capacity and personal liberty, being chemically and physically (e.g. chain) restrained, being exposed to verbal, physical and emotional abuse, and emphasis on institutional treatment were all extensive human rights violation that service users were experiencing in KMHH. Conclusion The available services for mental health service users are questionable due to mistrust and lack of awareness about rights of people with disabilities and need to be positively changed. Existing Mental Health Act has a large number of disparities with the CRPD and requires revision and adaptation in accordance to CRPD.
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RESUMO: Na sociedade contemporânea a diabetes tipo 2 e a obesidade estão a aumentar exponencialmente, representando um grave problema de saúde pública. De acordo com a IDF “A diabetes e a obesidade são o principal problema de saúde pública do século XXI’. Para além destas duas patologias, a prevalência de esteatose hepática não-alcoólica (NAFLD), entre a população obesa e diabética, é de cerca de 90%. O aumento da obesidade, diabetes e NAFLD tem uma forte correlação com o aumento do consumo de gorduras e açúcares, acompanhado de um decréscimo acentuado da actividade física. A obesidade, diabetes e NAFLD tem sido escrupolosamente investigada mas as terapêuticas disponíveis continuam a ser muito limitadas. Tendo em conta o número crescente e alarmante de obesos e diabéticos o conhecimento detalhado da patofisiologia da obesidade, diabetes e NAFLD, tendo em vista a necessidade extrema de desenvolvimento de novas estratégias terapêuticas, é da mais elevada urgência. O fígado é reconhecido como um orgão primordial no controlo da homeostase. No estado pós-prandial, o fígado converte a glucose em glicogénio e lípidos. Em contraste, no estado de jejum, o fígado promove a produção de glucose. Sistemas neuronais e hormonais, bem como o estado metabólico do fígado, controlam de forma muito precisa a alternância entre os diferentes substratos metabólicos, dependente do estado prandial. A insulina tem um papel central no controlo do metabolismo energético no fígado; se, por um lado, inibe a produção hepática de glucose e corpos cetónicos, por outro, promove a glicólise e a lipogénese. O metabolismo energético no fígado é também regulado por vários factores de transcrição e co-reguladores que, por sua vez, são regulados pela insulina, glucagina e outras hormonas metabólicas. Em conjunto, todos estes factores e reguladores vão controlar de forma muito estreita a gluconeogénese, a β-oxidação e a lipogénese, no fígado. Para além dos já conhecidos reguladores do metabolismo hepático, novas moléculas têm sido estudadas como tendo um papel fundamental na regulação do metabolismo energético no fígado. Qualquer desequilíbrio no metabolismo hepático vai contribuir para a insulino-resistência, NAFLD e diabetes tipo 2. O principal objectivo do trabalho de investigação aqui apresentado é o contributo para o estudo detalhado da patogénese da diabetes e obesidade, num contexto de dietas ricas em açúcares e gorduras, e com a perspectiva de explorar novas estratégias terapêuticas. Os objectivos específicos deste trabalho eram: primeiro, determinar se o tratamento com glutationo (GSH) e óxido nítrico (NO) era suficiente para melhorar a insulino-resistência associada ao elevado consumo de sacarose; segundo, determinar o papel da Rho-kinase 1 (ROCK1) na regulação do metabolismo hepático da glucose e dos lípidos; e terceiro, estudar o efeito do metilsulfonilmetano (MSM) em doenças metabólicas associadas à obesidade. Na primeira parte deste trabalho de investigação foram utilizados ratos Wistar machos sujeitos a uma dieta rica em sacarose (HS). Tal como esperado, estes animais apresentavam insulino-resistência e hiperinsulinémia. A dieta HS levou ao aumento dos níveis hepáticos de NO e ao decréscimo dos níveis de GSH no fígado. Em jejum, a administração intraportal de GSH e NO, a animais saudáveis promoveu um aumento significativo da sensibilidade à insulina. Também nestes animais, a administração intravenosa de S-nitrosotióis, compostos orgânicos que contém um grupo nitroso acoplado a um átomo de enxofre de um tiol, promoveu o aumento significativo da sensibilidade à insulina. Pelo contrário, em animais sujeitos à dieta HS, as doses padrão de GSH + NO e de S-nitrosotióis não conseguiram promover o aumento da sensibilidade à insulina. No entanto, ao aumentar a dose de S-nitrosotióis administrados por via intravenosa, foi possível observar o aumento da sensibilidade à insulina dependente da dose, indicando um possível papel dos S-nitrosotióis como sensibilizadores de insulina. O estudo detalhado do papel dos S-nitrosotióis na via de sinalização da insulina revelou que há um aumento da fosforilação do receptor da insulina (IR) e da proteína cinase B (Akt), sugerindo um efeito dos S-nitrosotióis nesta via de sinalização. Os resultados apresentados nesta primeira parte sugerem que os S-nitrosotióis promovem a correcta acção da insulina, podendo vir a ser importantes alvos terapêuticos. Na segunda parte deste trabalho de investigação utilizámos murganhos, com uma delecção específica da ROCK1 no fígado, e sujeitos a uma dieta rica em lípidos (HFD). Foi possível concluir que a ausência da ROCK1 no fígado previne a obesidade, melhora a sensibilidade à insulina e protege contra a esteatose hepática. A ausência de ROCK1 no fígado levou a um decréscimo significativo da expressão génica de genes associados à lipogénese, com uma diminuição acentuada do fluxo metabólico associado a esta via. Pelo contrário, a sobreexpressão de ROCK1, exclusivamente no fígado, promove a insulino-resistência e a esteatose hepática no contexto de obesidade induzida pela dieta. Para além disto, a delecção da ROCK1 no fígado de animais obesos e diabéticos, os murganhos deficientes em leptina, corroborou os dados obtidos no primeiro modelo animal, com a franca melhoria da hiperglicémia, hiperinsulinémia e esteatose hepática. Os dados que compõem esta parte do trabalho de investigação sugerem que a ROCK1 tem um papel crucial na regulação do metabolismo lipídico. Na terceira e última parte deste trabalho de investigação foi investigado o efeito do composto metilsulfunilmetano (MSM), um composto organosulfúrico naturalmente presente em plantas e utilizado também como suplemento dietético, em murganhos obesos e insulino-resistentes, por exposição a uma dieta rica em lípidos (DIO). O tratamento com MSM melhorou a insulino-resistência e protegeu contra a esteatose hepática. O conteúdo hepático em triglicéridos e colesterol também diminuíu de forma significativa nos animais DIO sujeitos ao tratamento com MSM, bem como a expressão génica associada à lipogénese. Para além disto, o tratamento com MSM levou a uma diminuição da expressão génica associada à inflamação. De realçar que o tratamento com MSM levou a uma melhoria do perfil hematopoiético destes animais, tanto na medula óssea como no sangue. Para comprovar o efeito benéfico do MSM na obesidade e insulino-resistência utilizámos murganhos deficientes no receptor da leptina, e por isso obesos e diabéticos, tendo observado um perfil semelhante ao obtido para murganhos sujeitos a uma dieta rica em lípidos e tratados com MSM. Concluímos, através dos dados recolhidos, que o MSM como suplemento pode ter efeitos benéficos na hiperinsulinémia, insulino-resistência e inflamação que caracterizam a diabetes tipo 2. Em resumo, os dados obtidos neste trabalho de investigação mostram que os S-nitrosotióis podem ter um papel importante como sensibilizadores da insulina, promovendo um aumento da sensibilidade à insulina num contexto de dietas ricas em sacarose. Para além disto, estudos in vitro, sugerem que os S-nitrosotióis regulam, especificamente, a via de sinalização da insulina. Este trabalho teve também como objectivo o estudo da ROCK1 como regulador do metabolismo da glucose e dos lípidos no fígado. Através do estudo de animais com uma delecção ou uma sobreexpressão da ROCK1 no fígado mostrou-se que esta tem um papel crucial na patogénese da obesidade e diabetes tipo 2, especificamente através do controlo da lipogénese de novo. Finalmente, foi também objectivo deste trabalho, explorar o efeito do MSM em animais DIO e deficientes em leptina. O tratamento com MSM protege de forma evidente contra a obesidade e insulino-resistência, com especial enfâse para a capacidade que esta molécula demonstrou ter na protecção contra a inflamação. Em conjunto os vários estudos aqui apresentados mostram que tanto os S-nitrosotióis como a ROCK1 têm um papel na patogénese da obesidade e diabetes tipo 2 e que a utilização de MSM como suplemento às terapêuticas convencionais pode ter um papel no tratamentos de doenças metabólicas.-------------------------------ABSTRACT: In modern western societies type 2 diabetes and obesity are increasing exponentially, representing a somber public concern. According to the International Diabetes Federation (IDF) ‘Diabetes and Obesity are the biggest public health challenges of the 21st century’. Aside from these the prevalence of nonalcoholic fatty liver disease (NAFLD), among the diabetic and obese population, is as high as 90%. It is now well established that the increase in obesity, diabetes and NAFLD strongly correlates with an increase in fat and sugar intake in our diet, alongside physical inactivity. The pathogenesis of obesity, diabetes and NAFLD has been thoroughly studied but the treatment options available are still narrow. Considering the alarming number in the obese and diabetic population the complete understanding of the pathogenesis, keeping in mind that new therapeutic strategies need to be attained, is of the highest urgency. The liver has been well established as a fundamental organ in regulating whole-body homeostasis. In the fed state the liver converts the glucose into glycogen and lipids. Conversely, in the fasted state, glucose will be produced in the liver. Neuronal and hormonal systems, as well as the hepatic metabolic states, tightly control the fast to fed switch in metabolic fuels. Insulin has a central role in controlling hepatic energy metabolism, by suppressing glucose production and ketogenesis, while stimulating glycolysis and lipogenesis. Liver energy metabolism is also regulated by various transcription factors and coregulators that are, in turn, regulated by insulin, glucagon and other metabolic hormones. Together, these regulators will act to control gluconeogenesis, β-oxidation and lipogenesis in the liver. Aside from the well-established regulators of liver energy metabolism new molecules are being studied has having a role in regulating hepatic metabolism. Any imbalance in the liver energy metabolism is a major contributor to insulin resistance, NAFLD and type 2 diabetes. The overall goal of this research work was to contribute to the understanding of the pathogenesis of diabetes and obesity, on a setting of high-sucrose and high-fat diets, and to explore potential therapeutic options. The specific aims were: first, to determine if treatment with glutathione (GSH) and nitric oxide (NO) was sufficient to ameliorate insulin resistance induced by high-sucrose feeding; second, to determine the physiological role of rho-kinase 1 (ROCK1) in regulating hepatic and lipid metabolism; and third, to study the effect of methylsulfonylmethane (MSM) on obesity-linked metabolic disorders. In the first part of this research work we used male Wistar rats fed a high-sucrose (HS) diet. As expected, rats fed a HS diet were insulin resistant and hyperinsulinemic. HS feeding increased hepatic levels of NO, while decreasing GSH. In fasted healthy animals administration of both GSH and NO, to the liver, was able to increase insulin sensitivity. Intravenous administration of S-nitrosothiols, organic compounds containing a nitroso group attached to the sulfur atom of a thiol, in fasted control animals also increased insulin sensitivity. Under HS feeding the standard doses of GSH + NO and S-nitrosothiols were unable to promote an increase in insulin sensitivity. However, the intravenous administration of increasing concentrations of S-nitrosothiols was able to restore insulin sensitivity, suggesting that S-nitrosothiols have an insulin sensitizing effect. Investigation of the effect of S-nitrosothiols on the insulin signaling pathway showed increased phosphorylation of the insulin receptor (IR) and protein kinase B (Akt), suggesting that S-nitrosothiols may have an effect on the insulin signaling pathway. Together, these data showed that S-nitrosothiols promote normal insulin action, suggesting that they may act as potential pharmacological tools. In the second part of this research work we used liver-specific ROCK1 knockout mice fed a high-fat (HF) diet. Liver-specific deletion of ROCK1 prevented obesity, improved insulin sensitivity and protected against hepatic steatosis. Deficiency of ROCK1 in the liver caused a significant decrease in the gene expression of lipogenesis associated gene, ultimately leading to decreased lipogenesis. Contrariwise, ROCK1 overexpression in the liver promoted insulin resistance and hepatic steatosis in diet-induced obesity. Furthermore, liver-specific deletion of ROCK1 in obese and diabetic mice, the leptin-deficient mice, improved the typical hyperglycemia, hyperinsulinemia and liver steatosis. Together, these data identify ROCK1 as a crucial regulator of lipid metabolism. In the third and final part of this research work we investigated the effect of MSM, an organosulfur compound naturally found in plants and used as a dietary supplement, on diet-induced obese (DIO) and insulin resistant mice. MSM treatment ameliorated insulin resistance and protected against hepatosteatosis. Hepatic content in triglycerides and cholesterol was significantly decreased by MSM treatment, as well as lipogenesis associated gene expression. Furthermore, MSM treated mice had decreased inflammation associated gene expression in the liver. Importantly, FACS analysis showed that MSM treatment rescued the inflammatory hematopoietic phenotype of DIO mice in the bone marrow and the peripheral blood. Moreover, MSM treatment of the obese and diabetic mice, the leptin-deficient mice, resulted in similar effects as the ones observed for DIO mice. Collectively, these data suggest that MSM supplementation has a beneficial effect on hyperinsulinemia, insulin resistance and inflammation, which are often found in type 2 diabetes. In conclusion, this research work showed that S-nitrosothiols may play a role as insulin sensitizers, restoring insulin sensitivity in a setting of high-sucrose induced insulin resistance. Furthermore, in vitro studies suggest that S-nitrosothiols specifically regulate the insulin signaling pathway. This research work also investigated the role of hepatic ROCK1 in regulation of glucose and lipid metabolism. Using liver-specific ROCK 1 knockout and ROCK1 overexpressing mice it was shown that ROCK1 plays a role in the pathogenesis of obesity and type 2 diabetes, specifically through regulation of the de novo lipogenesis pathway. Finally, this research work aimed to explore the effect of MSM in DIO and leptin receptor-deficient mice. MSM strongly protects against obesity and insulin resistance, moreover showed a robust ability to decrease inflammation. Together, the individual studies that compose this dissertation showed that S-nitrosothiols and ROCK1 play a role in the pathogenesis of obesity and type 2 diabetes and that MSM supplementation may have a role in the treatment of metabolic disorders.
Resumo:
ABSTRACT - The Portuguese National Health Service (SNS), a universal, centralized and public owned health care system, exhibits an extraordinary record of equalization in the access to health care and health gains in the late thirty years. However, the most recent history of the Portuguese health reform is pervaded by the influence of decentralization and privatization. Decentralization has been present in the system design since the 1976 Constitution, at least in theory. Private ownership of health care suppliers and out-ofpocket expenditures, on the financing side, both have a long tradition of relevance in the NHS mix of services. The initial aim of this study was to demonstrate expected parallelism between health reforms and public administration reforms, where a common pattern of joint decentralization and privatization was observed in many countries. Observers would be tempted to consider these two movements as common signs of new public management (NPM) developments. They have common objectives, are established around the core concepts of gains in effectiveness, efficiency, equity and quality of public services, through improved accountability. However, in practice, in Portugal, each movement was developed in a totally separated way. Besides those rooted in the NPM theory, there are few visible signs of association between decentralization and privatization. Decentralization, in the Portuguese SNS, was never intended to be followed by a privatization movement; it was seen merely as a public administration tool. Private management of health services, as stated in the most recent SNS legislation, was never intended to have decentralization as a condition or as a consequence. Paradoxically, in the Portuguese context, it has led invariably to centralized control. While presented as separate instruments for a common purpose, the association between decentralization and privatization still lacks a convincing demonstration. Many common health care management stereotypes remain to be checked out if we want to look for eventual associations between these two organizational tools.