16 research outputs found

    Evolution of active galactic nuclei

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    [Abriged] Supermassive black holes (SMBH) lurk in the nuclei of most massive galaxies, perhaps in all of them. The tight observed scaling relations between SMBH masses and structural properties of their host spheroids likely indicate that the processes fostering the growth of both components are physically linked, despite the many orders of magnitude difference in their physical size. This chapter discusses how we constrain the evolution of SMBH, probed by their actively growing phases, when they shine as active galactic nuclei (AGN) with luminosities often in excess of that of the entire stellar population of their host galaxies. Following loosely the chronological developments of the field, we begin by discussing early evolutionary studies, when AGN represented beacons of light probing the most distant reaches of the universe and were used as tracers of the large scale structure. This early study turned into AGN "Demography", once it was realized that the strong evolution (in luminosity, number density) of the AGN population hindered any attempt to derive cosmological parameters from AGN observations directly. Following a discussion of the state of the art in the study of AGN luminosity functions, we move on to discuss the "modern" view of AGN evolution, one in which a bigger emphasis is given to the physical relationships between the population of growing black holes and their environment. This includes observational and theoretical efforts aimed at constraining and understanding the evolution of scaling relations, as well as the resulting limits on the evolution of the SMBH mass function. Physical models of AGN feedback and the ongoing efforts to isolate them observationally are discussed next. Finally, we touch upon the problem of when and how the first black holes formed and the role of black holes in the high-redshift universe.Comment: 75 pages, 35 figures. Modified version of the chapter accepted to appear in "Planets, Stars and Stellar Systems", vol 6, ed W. Keel (www.springer.com/astronomy/book/978-90-481-8818-5). The number of references is limited upon request of the editors. Original submission to Springer: June 201

    Effect of esophagogastric devascularization with splenectomy on schistossomal portal hypertension patients' immunity Efeito da cirurgia de desconexão ázigo-portal com esplenectomia na imunidade de doentes com hipertensão portal esquistossomótica

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    BACKGROUND: Surgical treatment of hemorrhagic complication in schistosomal portal hypertension in our hospital is an esophagogastric devascularization procedure with splenectomy. Infectious risks and immunological alterations imputed to splenectomy may have significant importance. To minimize the consequences of spleen absence, the use of subtotal splenectomy and spleen auto-transplantation were stimulated. AIM: To verify the immunologic alterations imposed by this procedure in our patients. METHOD: Twenty-eight patients with schistosomal portal hypertension and previous history of upper digestive bleeding due to esophagogastric varices rupture underwent elective esophagogastric devascularization and splenectomy. They were prospectively studied before esophagogastric devascularization procedure with splenectomy, 15 and 30 days, 3 and 6 months after the procedure. T and B-lymphocytes, CD4 and CD8 subpopulations were determinated by monoclonal antibodies. Immunoglobulins A, M, G and C3, C4 components of the complement were determinated by radial immunodiffusion. RESULTS: We observed important reduction of all immune cells, increase of IgG and normal levels of IgM, IgA, C3 and C4 at preoperative. CD4/CD8 relation was normal. Six months after esophagogastric devascularization procedure with splenectomy, significant increase in T-lymphocytes, CD4, CD8 and B-lymphocytes were observed. CD4/CD8 relation remained normal. We noted significant increase in C3. IgA, IgM, IgG and C4 had increased, but without significant difference. CONCLUSION: Esophagogastric devascularization procedure with splenectomy determines an increase in T and B-lymphocytes, CD4 and CD8 subpopulations without compromising immunoglobulins and components of complement levels.<br>RACIONAL: A cirurgia de desconexão ázigo-portal com esplenectomia é utilizada no tratamento da complicação hemorrágica varicosa dos esquistossomóticos hepatoesplênicos com hipertensão do sistema portal, no Serviço de Fígado e Hipertensão Portal da Santa Casa de São Paulo. Envolvendo a esplenectomia, os riscos infecciosos e alterações imunológicas imputados a ela têm importância significativa. A esplenectomia subtotal e o auto-implante esplênico foram alternativas descritas para minimizar as conseqüências da esplenectomia nesses doentes. OBJETIVO: Avaliar o estado imunológico dos esquistossomóticos hepatoesplênicos e qual a alteração imunológica imposta pelo procedimento nesses doentes. MÉTODO: Vinte e oito esquistossomóticos com hipertensão portal e episódio hemorrágico varicoso foram estudados prospectivamente antes, 15 e 30 dias e 3 e 6 meses após a desconexão ázigo-portal com esplenectomia. Realizou-se contagem de linfócitos T, B, células CD4+ e CD8+ através de anticorpos monoclonais e dosagem das imunoglobulinas A, M, G e frações C3 e C4 do sistema complemento por imunodifusão radial. RESULTADOS: Obteve-se diminuição importante de todas as células, aumento de IgG e níveis normais de IgM, IgA, C3 e C4 no pré-operatório. A relação CD4+/CD8+ foi normal. Seis meses após a cirurgia, houve aumento significativo do número de linfócitos T, CD4+, CD8+ e linfócitos B. A relação CD4+/CD8+ manteve-se normal, sem variação. Houve aumento significativo nos níveis de C3. IgA, IgM, IgG e C4 também aumentaram, mas sem diferença significativa. CONCLUSÃO: Os linfócitos T, suas subpopulações CD4+ e CD8+, e os linfócitos B estão diminuídos no pré-operatório. Decorridos 6 meses da desconexão ázigo-portal com esplenectomia houve aumento do número de linfócitos T, das subpopulações CD4+ e CD8+, e dos linfócitos B. Após a desconexão ázigo-portal com esplenectomia não houve alteração das dosagens de imunoglobulinas nem diminuição do sistema complemento

    Transplante cardíaco: complicações apresentadas por pacientes durante a internação Trasplante de corazón: complicaciones que presentan los pacientes durante la hospitalización Heart Transplantation: complications presented by patients during the hospitalization

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    Com o avanço da ciência, a insuficiência cardíaca tem como possibilidade de intervenção o transplante cardíaco. Este trabalho teve como objetivos traçar o perfil demográfico dos pacientes submetidos ao transplante cardíaco e identificar as complicações apresentadas durante a internação. Trata-se de um estudo descritivo, quantitativo, realizado com 44 prontuários de pacientes submetidos a transplante de junho/2006 a julho/2009 em um Hospital Universitário de Belo Horizonte, Minas Gerais, Brasil. O projeto atendeu às recomendações da Resolução 196/96. Pelos resultados, a maioria dos pacientes era do sexo masculino, casada, escolaridade de nível fundamental e idade média de 45,2 anos. A miocardiopatia chagásica foi a principal causa de insuficiência cardíaca. As complicações predominantes foram alteração da glicemia, insuficiência renal e infecções. A taxa de mortalidade na internação foi de 20,4%. Além das complicações biológicas só foram registradas ansiedade e depressão. São necessárias pesquisas sobre o tema nos âmbitos psicossociais e espirituais, contribuindo para o desenvolvimento científico.<br>Hoy día, con los avances de la medicina y de la tecnología para el tratamiento de la insuficiencia cardiaca irreversible, se ha utilizado como última intervención el trasplante cardíaco. Este trabajo se desarrolló con los objetivos de delinear el perfil demográfico de los pacientes sometidos a trasplante cardíaco e identificar las complicaciones presentadas por ellos después del trasplante de corazón. Estudio descriptivo y cuantitativo, realizado en conjunto con los registros de 44 pacientes sometidos a trasplante de corazón desde Jun/2006 hasta Jul/2009, en un Hospital Universitario de Belo Horizonte, Minas Gerais, Brasil. El proyecto cumplió con las recomendaciones de la Resolución 196/96. Los resultados mostraron que la mayoría de los pacientes eran del sexo masculino, casados, con educación primaria y edad media de 45,2 años. Miocardiopatía chagásica fue la principal causa de insuficiencia cardíaca. Complicaciones que prevalecieron durante el ingreso fueron la alteración de la glucosa en la sangre, insuficiencia renal y las infecciones. La tasa de mortalidad fue del 20,4% durante la hospitalización. Además de las complicaciones biológicas, se registraron también ansiedad y depresión. Se hace necesario investigaciones sobre el tema en los ámbitos psicosociales y espirituales, contribuyendo al desarrollo científico.<br>Nowadays, with advance in technology and medicine the last alternative of treatment to heart failure is the cardiac transplantation. This work was developed with the following objectives to delineate the demographic profile of patients undergoing heart transplantation and complications presented by them after this procedure in the hospitalization. This is a descriptive and quantitative study conducted with the 44 records of patients undergoing heart transplantation from June/2006 to July/2009, in a University Hospital in Belo Horizonte, Minas Gerais, Brazil. The project attended to Resolution 196/96 recommendations. According to the results the majority of patients were male, married, with elementary education and the mid age of 45.2 years. The Chagasic cardiomyopathy was the main cause of heart failure. Complications that prevailed during the admission were alteration in blood glucose, kidney failure and infections. The mortality rate was 20.4% during hospitalization. In addition to biological complications were recorded only anxiety and depression. It is necessary to research on this subject in the psychosocial and spiritual spheres, contributing to the scientific development
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