984 resultados para ABSOLUTE STEREOSTRUCTURES
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Introdução: As provas epicutâneas (PE) são o exame complementar de diagnóstico indicado para avaliação de suspeita de dermite de contacto alérgica. Idealmente, devem ser realizadas sem que o doente se encontre sob imunossupressores. Existem contudo situações clínicas em que tal não é possível, não havendo informação disponível acerca de como realizar e valorizar os resultados das PE nestes doentes. O objectivo do presente trabalho é rever a literatura no que concerne à realização de PE sob imunossupressão iatrogénica. Material e Métodos: Revisão da literatura relevante para o tema publicada até Janeiro de 2015 e indexada à Medline. Resultados: De acordo com o reportado na literatura, foram realizadas PE em 77 doentes sob corticóide sistémico, 78 doentes sob ciclosporina (CyA), 6 sob azatioprina, 10 sob metotrexato (MTX), 4 sob micofenolato de mofetil (MMF), 11 sob fármacos anti-factor de necrose tumoral e 7 sob fármaco anti-IL-12/23. Foram ainda descritos 15 casos de realização de PE sob associação de imunossupressores. Verificaram-se reacções positivas em todos os grupos. Conclusão: O tratamento concomitante com imunossupressores não deve ser uma contra-indicação para realização de PE, estando descritas reacções positivas em doentes sob prednisolona, azatioprina, CyA, MTX, MMF, infliximab, etanercept, adalimumab e ustecinumab. Os resultados negativos ou duvidosos devem, contudo, ser interpretados de forma cautelosa.
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INTRODUCTION: With the introduction of combination antiretroviral therapy (cART), prognosis of human immunodeficiency virus (HIV) infection has been improved and kidney transplantation (KT) in HIV-positive patients became possible. METHODS: We reviewed the demographic, clinical, laboratory, and therapeutic data of all the HIV-infected patients who underwent KT between 2009 (first KT in Portugal in a HIV-infected patient) and May 2014. Case accrual was through all Portuguese KT centers where a KT in an HIV-infected patient was performed. Patients were transplanted following the American and Spanish guideline recommendations that included maintenance on cART, undetectable plasma HIV RNA copies, and absolute CD4 counts of ≥ 200 cells/μL in the last 6 months. RESULTS: Fourteen KT were performed on men and 3 on women. The mean age of patients at the time of transplantation was 49.9 ± 11.7 years. HIV status was known for 12 ± 5 years. Eight patients had AIDS in the past and all patients received grafts from deceased donors. Twelve patients (64.7%) underwent induction therapy with basiliximab and 2 patients experienced early graft loss. In 2 patients, humoral rejection was diagnosed and in 3 patients, cellular rejection. Two patients died and an additional patient had early graft loss. CONCLUSION: KT is a possible, but challenging, renal replacement therapy in selected HIV-positive patients. Even in those with AIDS criteria in the past, when the disease is controlled, and after the reconstitution of the immune system with cART, KT can be performed. Nevertheless, the risk-benefit ratio for each patient needs to be taken in consideration.
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BACKGROUND: The baseline susceptibility of primary HIV-2 to maraviroc (MVC) and other entry inhibitors is currently unknown. METHODS: The susceptibility of 19 HIV-2 isolates obtained from asymptomatic and AIDS patients and seven HIV-1 clinical isolates to the fusion inhibitors enfuvirtide (ENF) and T-1249, and to the coreceptor antagonists AMD3100, TAK-779 and MVC, was measured using a TZM-bl cell-based assay. The 50% inhibitory concentration (IC(50)), 90% inhibitory concentration (IC(90)) and dose-response curve slopes were determined for each drug. RESULTS: ENF and T-1249 were significantly less active on HIV-2 than on HIV-1 (211- and 2-fold, respectively). AMD3100 and TAK-779 inhibited HIV-2 and HIV-1 CXCR4 tropic (X4) and CCR5 tropic (R5) variants with similar IC(50) and IC(90) values. MVC, however, inhibited the replication of R5 HIV-2 variants with significantly higher IC(90) values (42.7 versus 9.7 nM; P<0.0001) and lower slope values (0.7 versus 1.3; P<0.0001) than HIV-1. HIV-2 R5 variants derived from AIDS patients were significantly less sensitive to MVC than variants from asymptomatic patients, this being inversely correlated with the absolute number of CD4(+) T-cells. CONCLUSIONS: T-1249 is a potent inhibitor of HIV-2 replication indicating that new fusion inhibitors might be useful to treat HIV-2 infection. Coreceptor antagonists TAK-779 and AMD3100 are also potent inhibitors of HIV-2 replication. The reduced sensitivity of R5 variants to MVC, especially in severely immunodeficient patients, indicates that the treatment of HIV-2-infected patients with MVC might require higher dosages than those used in HIV-1 patients, and should be adjusted to the disease stage.
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Several risk factors for asthma have been identified in infants and young children with recurrent wheeze. However, published literature has reported contradictory findings regarding the underlying immunological mechanisms. OBJECTIVES: This study was designed to assess and compare the immunological status during the first 2 years in steroid-naive young children with >or= three episodes of physician-confirmed wheeze (n=50), with and without clinical risk factors for developing subsequent asthma (i.e. parental asthma or a personal history of eczema and/or two of the following: wheezing without colds, a personal history of allergic rhinitis and peripheral blood eosinophilia >4%), with age-matched healthy controls (n=30). METHODS: Peripheral blood CD4(+)CD25(+) and CD4(+)CD25(high) T cells and their cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), GITR and Foxp3 expression were analysed by flow cytometry. Cytokine (IFN-gamma, TGF-beta and IL-10), CTLA-4 and Foxp3 mRNA expression were evaluated (real-time PCR) after peripheral blood mononuclear cell stimulation with phorbol 12-myristate 13-acetate (PMA) (24 h) and house dust mite (HDM) extracts (7th day). RESULTS: Flow cytometry results showed a significant reduction in the absolute number of CD4(+)CD25(high) and the absolute and percentage numbers of CD4(+)CD25(+)CTLA-4(+) in wheezy children compared with healthy controls. Wheezy children at a high risk of developing asthma had a significantly lower absolute number of CD4(+)CD25(+) (P=0.01) and CD4(+)CD25(high) (P=0.04), compared with those at a low risk. After PMA stimulation, CTLA-4 (P=0.03) and Foxp3 (P=0.02) expression was diminished in wheezy children compared with the healthy children. After HDM stimulation, CTLA-4 (P=0.03) and IFN-gamma (P=0.04) expression was diminished in wheezy children compared with healthy children. High-risk children had lower expression of IFN-gamma (P=0.03) compared with low-risk and healthy children and lower expression of CTLA-4 (P=0.01) compared with healthy children. CONCLUSIONS: Although our findings suggest that some immunological parameters are impaired in children with recurrent wheeze, particularly with a high risk for asthma, further studies are needed in order to assess their potential as surrogate predictor factors for asthma in early life.
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics
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HIV-l isolation was attempted on 72 individuais, including persons with knoum HIV infection and five without proven HIV infection but with indeterminate Western blot patterns, as well as on low-risk HIV seronegative persons. The ahility to detect HIV- 1 frorn culture supernatant by p24 antigen capture assay was evaluated by segregating patients by absolute CD4+ cell counts, clinicai stage of disease, p24 antigenemia and zidovudine use. The likelihood of a p24 positive HIV culture was highest among patients with CD4+ T-cell counts below 200/ul and patients with advanced clinical disease. Use of zidovudine did not affect the rate ofHIV positwity in cultures.
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Dissertation to obtain the degree of Doctor of Philosophy in Biomedical Engineering
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We reviewed the cerebrospinal fluid (CSF) syndromes of 100 consecutive HIV-positive patients presenting acute consciousness compromise in emergency rooms, and correlated them with clinical data. The most frequent CSF syndromes were: absolute protein-cytological dissociation (21), viral (19), neurocryptococcosis (7), relative protein-cytological dissociation (6) and septic (4), moderate hypoglycorrachia (4), severe hypoglycorrachia (4) and hydroelectrolytic disturbance (3). One fifth of the patients had CSF syndromes considered sufficient for diagnosis or an immediate clinical decision. The most common clinical data were infective and neurological. There was little correlation between the clinical data and the CSF syndromes. We conclude that in HIV-positive individuals presenting acute consciousness disturbances there are frequently non-specific results in the CSF analysis that must be weighed against a detailed history and thorough physical examination. Taking this into account, in about one fifth of cases the CSF analysis can offer useful information for treatment.
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RESUMO: De acordo com o estado da arte, existem intervenções psicofarmacológicas, psicológicas e psicossocias, com evidência científica dos seus resultados, no tratamento de pessoas com esquizofrenia e perturbação esquizoafectiva. No entanto, muitos destes doentes, não procuram ajuda dos serviços de saúde mental, não recebem os referidos cuidados ou não são detectados nem seguidos por estes. Esta realidade levou ao desenvolvimento de programas integrados, intervenções e estudos mais específicos, nomeadamente para tentar ultrapassar os obstáculos na acessibilidade aos cuidados de saúde e na continuidade de seguimento destes doentes. No conjunto das dificuldades apuradas, as questões da exequibilidade (feasibility) e da implementação, têm tido particular relevo na literatura científica recente, bem como a melhor forma de vencer as respectivas barreiras e adaptar essas intervenções às varias realidades, culturas e recursos. Objectivos: Objectivos gerais:1) Avaliar a exequibilidade e a implementação inicial de um programa de cuidados integrados, para pessoas com esquizofrenia ou perturbação esquizoafectiva, no contexto clínico das equipas de saúde mental comunitárias de um departamento de psiquiatria do Serviço Nacional de Saúde, em Portugal, com os recursos materiais e humanos existentes; 2) Avaliar o impacto deste programa, nestes doentes e na respectiva prestação de cuidados de saúde mental. Metodologia. Elaborámos um programa de cuidados integrados (Programa Integrar) com base no modelo clínico de case management, com seguimento mantido e integrado. Cada doente passou a ter um terapeuta de referência, um plano individual de cuidados e manteve o seguimento com o seu psiquiatra assistente. Foram seleccionadas intervenções, nomeadamente, psicoeducativas, familiares, estratégias para lidar com os sintomas e a doença, prevenção de recaídas e intervenções para melhorar o funcionamento social e ocupacional. A estas intervenções foi sempre associado o tratamento psicofarmacológico. O estudo delineado incluiu dois componentes: avaliação da exequibilidade e implementação inicial do programa de cuidados integrados (componente A) e avaliação do impacto deste programa (componente B), através de um estudo de intervenção, prospectivo, naturalista, não aleatorizado e não ontrolado. A amostra do estudo resultou das sucessivas referenciações, para o Programa Integrar, de pessoas com os diagnósticos de esquizofrenia ou perturbação esquizoafectiva, seguidas nas cinco equipas de saúde mental comunitárias do Departamento de Psiquiatria do Centro Hospitalar de Lisboa Ocidental, com uma área assistencial correspondente a uma população de, aproximadamente, 400 000 pessoas. Definimos etapas, estratégias, parâmetros e indicadores para o estudo da exequibilidade do programa. Efectuámos a monitorização e a avaliação de tarefas, procedimentos e intervenções recomendadas aos terapeutas de referência. Realizámos duas avaliações, uma no início do programa e outra após um ano de intervenção. Foram avaliadas as seguintes dimensões (com indicação do acrónimo do instrumento de avaliação utilizado entre parêntesis): psicopatologia (BPRS), depressão (MADRS), necessidades (CAN), incapacidade (DAS), actividade social e ocupacional (SOFAS), atitude em relação à medicação (DAI), insight (SAI), qualidade de vida (WHOQOL-S) e satisfação (POCS). Resultados: Dos 146 doentes que foram incluídos no estudo, 97 (66%) eram do sexo masculino e 49 (34%) do sexo feminino, com uma idade média de 36 anos. Destes oentes,116 (79,4%)tinham o diagnóstico (ICD10) de esquizofrenia e 30 (20,6%) de perturbação esquizoafectiva. Os restantes dados sociodemográficos eram típicos de populações afins em serviços de saúde mental nacionais. Do total de doentes (146) que iniciaram o estudo, 26 (18%) abandonaram o seguimento neste programa. Para o componente A da investigação (estudo de exequibilidade) salientamos: exerceram funções a totalidade (15) dos terapeutas de referência que receberam formação, 76 % efectuaram o número mínimo recomendado de sessões / ano por doente (≥18), 44,9 fizeram o número mínimo de sessões familiares pretendido (≥ 3). Nas intervenções mais específicas foram atingidos os objectivos em mais de 75% dos doentes, à excepção das intervenções domiciliárias (19,4%), prevenção do abuso de substâncias (45,4%) e do risco de suicídio (34,3%). O plano individual de cuidados foi realizado em 98 % dos doentes e em 38,9 % dos casos ocorreu a participação da família. Neste plano, a média de objectivos definidos foi de 5 e a média de objectivos atingidos correspondeu a 3 (p= 0,001). Na primeira avaliação, estavam a frequentar estruturas de reabilitação psicossocial 42 doentes (28,8%) e,12 meses após, esse número passou para 80 (74,1%).Também aumentou o número de doentes com actividade profissional a tempo completo, de 8 (7,4%) para 18 (16,7%). No componente B do estudo (avaliação do impacto do programa), em termos de psicopatologia, e para as pontuações médias globais do BPRS, ocorreu uma diminuição entre a primeira e a segunda avaliação (p=0,001), tal como nas subescalas: sintomas positivos (p=0,003), sintomas negativos (p=0,002), sintomas de mania (p=0,002) e sintomas de depressão/ansiedade (p=0,001). Na avaliação da depressão (p= 0,001) e da incapacidade (p=0,003), as diferenças foram significativas e favoráveis. O mesmo não sucedeu na atitude em relação à medicação (p=0,690) nem na escala de avaliação do insight (p=0,079). Em relação ao funcionamento social e ocupacional, qualidade de vida e satisfação dos doentes, ocorreu uma melhoria significativa da primeira para a segunda avaliação As necessidades sem resposta mais frequentes, na primeira avaliação, corresponderam aos itens: actividades diárias, contactos sociais, relações íntimas, relacionamento sexual, benefícios sociais, sintomas psicóticos, sofrimento psicológico, informação sobre a doença / tratamento e gestão/problemas de dinheiro. Para todos estes últimos nove itens, verificou-se uma diferença estatisticamente significativa, entre a primeira e a segunda avaliação, com diminuição destas necessidades, excepto nas relações íntimas, relacionamento sexual e nos problemas de dinheiro. Na distribuição dos três estados de necessidades, para todos os itens, diminuíram as necessidades sem resposta e as necessidades com resposta parcial e aumentaram as situações em que deixaram de se verificar necessidades relevantes. Dos resultados obtidos para outros indicadores clínicos e de utilização dos cuidados, será importante referir que na comparação do ano anterior com o ano em que decorreu o programa, o número de doentes da amostra internados diminuiu 64,1%, bem como a média do número de internamentos (p=0,001). Em relação à duração dos internamentos, no ano anterior ao programa, os 39 doentes internados, tiveram um total de dias de internamento de 1522, sendo que, no ano do programa, para os 14 doentes internados, o total foi de 523 dias. Em termos absolutos, ocorreu uma redução de 999 dias (menos 65,6% dias). Também se verificou uma diminuição de 45,6 % de recaídas (p=0,001).Discussão e conclusões A exequibilidade do programa de cuidados integrados permitiu a aplicação do modelo clínico de case management, com seguimento mantido e integrado, através do qual cada doente passou a ter um terapeuta de referência assim como, em 98% casos, um plano individual de cuidados. As famílias continuaram a ser o principal suporte para os doentes, mas surgiram dificuldades quando se pretendeu uma participação mais activa destas no tratamento.A diminuição do número e da duração dos internamentos constituíram importantes resultados com implicações não só em termos clínicos mas também económicos. Os valores obtidos, para as diferentes variáveis, também sugerem o impacto favorável do Programa Integrar a nível da psicopatologia, das necessidades, da incapacidade, do funcionamento social e ocupacional, da qualidade de vida e da satisfação dos doentes. O mesmo não sucedeu para o insight e para a mudança de atitudes dos doentes em relação à medicação, resultados que devem ser igualmente considerados em futuros reajustamentos deste programa ou no desenvolvimento de novos programas. Como principais conclusões podemos referir que: 1) Foi possível a exequibilidade de um programa de cuidados integrados inovador e a implementação inicial desse programa, para doentes com esquizofrenia ou perturbação esquizoafectiva, com os recursos humanos e materiais existentes, no contexto clínico das equipas de saúde mental comunitárias, de um departamento de psiquiatria e saúde mental, em Portugal; 2) Na avaliação do impacto do programa, os resultados obtidos indiciam potencialidades de aplicação, deste programa de cuidados integrados, com vista à melhoria clínica e psicossocial destes doentes. Devem ser realizados estudos de replicação, ou complementares à presente investigação, no entanto, os dados obtidos são encorajadores para o desenvolvimento de programas similares, a nível nacional e internacional, que possam beneficiar um grupo mais alargado de doentes.------------ABSTRACT: Although there are psychological and psychosocial interventions well supported by scientific evidence, which show benefit when combined with psychopharmacological treatments, we know that a significant number of people with schizophrenia or schizoaffective disorders, do not seek help from mental health services, do not receive the care mentioned and are not detected or followed-up by them. This reality led to the development of integrated programs, interventions and more specific studies, to try to overcome the obstacles in the accessibility to the health services and on the follow-up of these patients. Amongst the barriers identified, feasibility and implementation of those programs have been of special relevance in recent scientific literature, as well as the best way to overcome such difficulties and adapt the interventions to the various realities, cultures and resources. Objectives: General objectives were defined: 1) Assessment of the feasibility and initial implementation of an integrated care program, for people with schizophrenia or schizoaffective disorder, in the clinical setting of community mental health teams, in a psychiatric department from the national health service in Portugal; 2) Impact evaluation of the integrated care program, for these patients and their mental health care delivery. Methods: We drew up an integrated care program (Program Integrar) based on the clinical case management model, with continuous and integrated follow-up. Each patient got one case manager, an individual care plan and kept the same psychiatrist. Were selected the appropriated interventions, namely: psycho-educative, family-based interventions, strategies for dealing with the symptoms and the disorder, relapse prevention and interventions to improve social and occupational functioning. These interventions were always associated with psychopharmacological treatment. The investigation was outline with two parts: assessment of the feasibility and initial implementation of the Program Integrar (part A of the study) and impact evaluation of the program (part B of the study). We designed a naturalistic, prospective, intervention study, non-randomized and without control group. Our chosen sample was made with successive referrals of patients with the diagnosis of schizophrenia or schizoaffective disorder, followedup in one of the five community mental health teams of the Psychiatric Department of Centro Hospitalar Lisboa Ocidental, with a catchment area for a population of about 400 000 people. Different stages, strategies, criteria and indicators for studying the feasibility of the program and its implementation were set and the tasks, procedures and recommended interventions of the case managers were monitored and evaluated. We did two assessments with an interval of one year and we evaluated the following dimensions (the acronym of the assessment instrument used in brackets): psychopathology (BPRS), depression (MADRS), needs (CAN), disability (DAS), social and occupational functioning (SOFAS), attitude toward medication (DAI), insight (SAI), quality of life (WHOQOL-S) and satisfaction (POCS). Results: Of the 146 patients who started the study, 97 (66%) were male and 49 (34%) females with a mean age of 36 years. Of these, 116 (79,4%) were diagnosed (ICD10) with schizophrenia and 30 (20,6%) with schizoaffective disorder. The other socio-demographic data were typical of populations within Portuguese mental health services. Of all patients (146), who started the program, 26 (18%) of patients left the program (program dropout rate). Of the regarding part A of the study, which focused on feasibility, the following is of note: all professionals who had been trained for this purpose (15) acted as case manager, 76% did the recommended minimum number of sessions / year per patient (≥18) and 44,9% did the minimum number of family sessions desired (≥ 3). For the more specific interventions the parameters set out were met for more than 75% of patients, with the exception of domiciliar interventions (19.4%), prevention of substance abuse (45.4%) and suicide risk prevention(34.3%). The individual care plan was done for 98% of patients and in 38,9% of cases this involved family participation. For this plan the mean objectives defined were 5 and in average was achieved 3 (p=0,001). On the first assessment, 42 patients (28.8%) were attending psychosocial rehabilitation structures and 12 months later that number rose up to 80 (74,1%). Regarding their employment status, in the first assessment 8 (7,4%) were in full time employment and in the second evaluation the number rise to 18 (16,7%). For part B of the study (impact program evaluation), in terms of psychopathology, global mean scores for the BPRS, decreased (p=0,001), as did the four sub scales: positive symptoms (p=0,003); negative symptoms (p=0,002); manic symptoms (p=0,002) and symptoms of depression/anxiety (p=0,001). Both in the evaluation of depression (p=0,001), as in the assessment of disability (p=0,003), the differences were significant. However, this was not the case with attitudes towards medication (p=0,690) and with insight evaluation (p=0,079). In relation to social and occupational functioning, quality of life and patient satisfaction there was a statistically significant improvement from the first to the second assessment. The most commonly unmet needs in the first assessment were daily activities, social contacts, intimate relationships, sexual relations, social benefits, psychotic symptoms,psychological distress, information about the disorder / treatment and money problems money management. Of these, in the second assessment, all of those nine unmet needs showed significant improvement, excepted intimate relationships, sexual relations and Money problems / money management. In the distribution of the three states of needs for all items, it happened a decreased in unmet needs and partially met needs and increased in the situations where relevant needs were no longer found. For other clinical indicators it is important to note, when we compared the year prior to this program and the year after, there were fewer hospitalizations (reduction of 64,1% of admissions) and in the mean number of admissions (p=0,001). Regarding the length of hospitalization in the year prior to the program, the 39 patients admitted had a total of 1522 hospital days, and in the year of the program for the 14 hospitalized patients, the total was 523 days. In absolute terms, there was a reduction of 999 days (65,6%). There was also a 45,6% reduction of relapses (p = 0,001). Discussion and Conclusions: The feasibility of the integrated care program allowed the application of the clinical case management model, with continuous follow-up. Each patient got a case manager and in 98% of the cases they also got an individual plan of care. Families continued to be the main support for patients but, difficulties occurred when it was claimed a more active participation. The decrease in the number and duration of admissions were important findings with implications not only in clinical terms but also in economic field. The achieved results for the different variables can also indicate the favorable impact of this program, at the level of psychopathology, needs, disability, social and occupationa functioning, quality of life and patient satisfaction. The same did not happen for the evaluation of insight and in the changes of attitudes towards medication. These data should also be considered for future readjustments of this program and for the developing of new programs.Finally, the two-overview conclusions are: 1) It was possible the feasibility of an integrated care program and initial implementation of this innovative program, for patients with schizophrenia or schizoaffective disorder, with the human and material resources available in the clinical context of the community mental health teams, in a psychiatry and mental health department of the national health service in Portugal; 2) In assessing the impact of the program, the results suggest potential application of this integrated care program, to improve clinical state and psychosocial variables for these patients. There should be done studies to replicate these results, however the results obtained are promising for the development of similar programs at nationally and internationally level, that could benefit a wider group of patients.
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics
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Dissertação para obtenção do Grau de Doutor em Engenharia do Ambiente
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The objective of the present study was to evaluate the usefulness of molecular methodologies to access human papillomavirus genome in the genital tract. Samples from 136 women aged 17 to 52 years old obtained from the Dr. Sérgio Franco Laboratories between 2000 and 2001, were analyzed by the hybrid capture assay and amplified by PCR with generic primers MY09/MY11 and specific primers for types 16, 18, 31, 33, 35, 58. Viral genome was detected in 71.3% of the samples by hybrid capture and 75% by amplification. When cytopathology was used as a reference method for screening lesions, hybrid capture (p=0) and amplification (p=0.002) presented positive association. The 3 methods showed absolute agreement when cytopathology confirmed papillomavirus infection and high grade intraepithelial lesion. Disagreements occurred for 10 cases: seven inflammatory cases positive by PCR and negative for hybrid capture and 3 low squamous intraepithelial lesions positive for hybrid capture but negative for amplification. In conclusion, hybrid capture was shown to be sensitive and specific enough for use in clinical routines. Moreover, the evaluation of viral load values obtained by this method were shown to be related to the severity of the lesion and merit further studies to analyze the possible association with risk of progression to malignancy.
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Nowadays, several sensors and mechanisms are available to estimate a mobile robot trajectory and location with respect to its surroundings. Usually absolute positioning mechanisms are the most accurate, but they also are the most expensive ones, and require pre installed equipment in the environment. Therefore, a system capable of measuring its motion and location within the environment (relative positioning) has been a research goal since the beginning of autonomous vehicles. With the increasing of the computational performance, computer vision has become faster and, therefore, became possible to incorporate it in a mobile robot. In visual odometry feature based approaches, the model estimation requires absence of feature association outliers for an accurate motion. Outliers rejection is a delicate process considering there is always a trade-off between speed and reliability of the system. This dissertation proposes an indoor 2D position system using Visual Odometry. The mobile robot has a camera pointed to the ceiling, for image analysis. As requirements, the ceiling and the oor (where the robot moves) must be planes. In the literature, RANSAC is a widely used method for outlier rejection. However, it might be slow in critical circumstances. Therefore, it is proposed a new algorithm that accelerates RANSAC, maintaining its reliability. The algorithm, called FMBF, consists on comparing image texture patterns between pictures, preserving the most similar ones. There are several types of comparisons, with different computational cost and reliability. FMBF manages those comparisons in order to optimize the trade-off between speed and reliability.
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RESUMO: Apesar de toda a evolução farmacológica e de meios complementares de diagnóstico possível nos últimos anos, o enfarte agudo do miocárdio e a morte súbita continuam a ser a primeira manifestação da aterosclerose coronária para muitos doentes, que estavam previamente assintomáticos. Os exames complementares de diagnóstico tradicionalmente usados para avaliar a presença de doença coronária, baseiam‐se na documentação de isquémia do miocárdio e por este motivo a sua positividade depende da presença de lesões coronárias obstrutivas. As lesões coronárias não obstrutivas estão também frequentemente implicadas no desenvolvimento de eventos coronários. Apesar de o risco absoluto de instabilização por placa ser superior para as lesões mais volumosas e obstrutivas, estas são menos prevalentes do que as placas não obstrutivas e assim, por questões probabilísticas, os eventos coronários resultam com frequência da rotura ou erosão destas últimas. Estudos recentes de imagiologia intracoronária avançada forneceram evidência de que apesar de ser possível identificar algumas características de vulnerabilidade em placas associadas ao desenvolvimento subsequente de eventos coronários, a sua sensibilidade e especificidade é muito baixa para aplicação clínica. Mais do que o risco associado a uma placa em particular, para o doente poderá ser mais importante o risco global da sua árvore coronária reflexo da soma das probabilidade de todas as suas lesões, sendo que quanto maior for a carga aterosclerótica maior será o seu risco. A angio TC cardíaca é a mais recente técnica de imagem não invasiva para o estudo da doença coronária e surgiu nos últimos anos fruto de importantes avanços na tecnologia de TC multidetectores. Estes avanços, permitiram uma progressiva melhoria da resolução espacial e temporal, contribuindo para a melhoria da qualidade dos exames, bem como uma significativa redução da dose de radiação. A par desta evolução tecnológica, foi aumentando a experiência e gerada mais evidência científica, tornando a angio TC cardíaca cada vez mais robusta na avaliação da doença coronária e aumentando a sua aplicabilidade clínica. Mais recentemente apareceram vários trabalhos que validaram o seu valor prognóstico, assinalando a sua chegada à idade adulta. Para além de permitir excluir a presença de doença coronária e de identificar a presença de estenoses significativas, a angio TC cardíaca permite identificar a presença de lesões coronárias não obstrutivas, característica impar desta técnica como modalidade de imagem não invasiva. Ao permitir identificar a totalidade das lesões ateroscleróticas (obstrutivas e não obstrutivas), a 18 angio TC cardíaca poderá fornecer uma quantificação da carga aterosclerótica coronária total, podendo essa identificação ser útil na estratificação dos indivíduos em risco de eventos coronários. Neste trabalho foi possível identificar preditores demográficos e clínicos de uma elevada carga aterosclerótica coronária documentada pela angioTC cardíaca, embora o seu poder discriminativo tenha sido relativamente modesto, mesmo quando agrupados em scores clínicos. Entre os vários scores, o desempenho foi um pouco melhor para o score de risco cardiovascular Heartscore. Estas limitações espelham a dificuldade de prever apenas com base em variáveis clínicas, mesmo quando agrupadas em scores, a presença e extensão da doença coronária. Um dos factores de risco clássicos, a obesidade, parece ter uma relação paradoxal com a carga aterosclerótica, o que pode justificar algumas limitações da estimativa com base em scores clínicos. A diabetes mellitus, por outro lado, foi um dos preditores clínicos mais importantes, funcionando como modelo de doença coronária mais avançada, útil para avaliar o desempenho dos diferentes índices de carga aterosclerótica. Dada a elevada prevalência de placas ateroscleróticas identificáveis por angio TC na árvore coronária, torna-‐se importante desenvolver ferramentas que permitam quantificar a carga aterosclerótica e assim identificar os indivíduos que poderão eventualmente beneficiar de medidas de prevenção mais intensivas. Com este objectivo, foi desenvolvido um índice de carga aterosclerótica que reúne a informação global acerca da localização, do grau de estenose e do tipo de placa, obtida pela angio TC cardíaca, o CT--‐LeSc. Este score poderá vir a ser uma ferramenta útil para quantificação da carga aterosclerótica coronária, sendo de esperar que possa traduzir a informação prognóstica da angio TC cardíaca. Por fim, o conceito de árvore coronária vulnerável poderá ser mais importante do que o da placa vulnerável e a sua identificação pela angio TC cardíaca poderá ser importante numa estratégia de prevenção mais avançada. Esta poderá permitir personalizar as medidas de prevenção primária, doseando melhor a sua intensidade em função da carga aterosclerótica, podendo esta vir a constituir uma das mais importantes indicações da angio TC cardíaca no futuro.---------------- ABSTRACT Despite the significant advances made possible in recent years in the field of pharmacology and diagnostic tests, acute yocardial infarction and sudden cardiac death remain the first manifestation of coronary atherosclerosis in a significant proportion of patients, as many were previously asymptomatic. Traditionally, the diagnostic exams employed for the evaluation of possible coronary artery disease are based on the documentation of myocardial ischemia and, in this way, they are linked to the presence of obstructive coronary stenosis. Nonobstructive coronary lesions are also frequently involved in the development of coronary events. Although the absolute risk of becoming unstable per plaque is higher for more obstructive and higher burden plaques, these are much less frequent than nonobstructive lesions and therefore, in terms of probability for the patient, coronary events are often the result of rupture or erosion of the latter ones. Recent advanced intracoronary imaging studies provided evidence that although it is possible to identify some features of vulnerability in plaques associated with subsequente development of coronary events, the sensitivity and sensibility are very limited for clinical application. More important than the individual risk associated with a certain plaque, for the patient it might be more important the global risk of the total coronary tree, as reflected by the sum of the diferent probabilities of all the lesions, since the higher the coronary Atherosclerotic burden, the higher the risk for the patient. Cardiac CT or Coronary CT angiography is still a young modality. It is the most recente noninvasive imaging modality in the study of coronary artery disease and its development was possible due to important advances in multidetector CT technology. These allowed significant improvements in temporal and spatial resolution, leading to better image quality and also some impressive reductions in radiation dose. At the same time, the increasing experience with this technique lead to a growing body of scientific evidence, making cardiac CT a robust imaging tool for the evaluation of coronary artery disease and increased its clinical indications. More recently, several publications documented its prognostic value, marking the transition of cardiac CT to adulthood. Besides being able to exclude the presence of coronary artery disease and of obstructive lesions, Cardiac CT allows also the identification of nonobstructive lesions, making this a unique tool in the field of noninvasive imaging modalities. By evaluating both obstructive and nonobstructive lesions, cardiac CT can provide for the quantification of total coronary atherosclerotic burden, and this can be useful to stratify the risk of future coronary events. In the present work, it was possible to identify significant demographic and clinical predictors of a high coronary atherosclerotic burden as assessed by cardiac CT, but with modest odds ratios, even when the individual variables were gathered in clinical scores. Among these diferent clinical scores, the performance was better for the Heartscore, a cardiovascular risk score. This modest performance underline the limitations on predicting the presence and severity of coronary disease based only on clinical variables, even when optimized together in risk scores, One of the classical risk factors, obesity, had in fact a paradoxical relation with coronary atherosclerotic burden and might explain some of the limitations of the clinical models. On the opposite, diabetes mellitus was one of the strongest clinical predictors, and was considered to be a model of more advanced coronary disease, useful to evaluate the performance of diferent plaque burden scores. In face of the high prevalence of plaques that can be identified in the coronary tree of patients undergoing cardiac CT, it is of utmost importance to develop tools to quantify the total coronary atherosclerotic burden providing the identification of patients that could eventually benefit from more intensive preventive measures. This was the rational for the development of a coronary atherosclerotic burden score, reflecting the comprehensive information on localization, degree of stenosis and plaque composition provided by cardiac CT – the CT-LeSc. This score may become a useful tool to quantify total coronary atherosclerotic burden and is expected to convey the strong prognostic information of cardiac CT. Lastly, the concept of vulnerable coronary tree might become more important than the concept of the vulnerable plaque and his assessment by cardiac CT Might become important in a more advance primary prevention strategy. This Could lead to a more custom-made primary prevention, tailoring the intensity of preventive measures to the atherosclerotic burden and this might become one of the most important indications of cardiac CT In the near future.