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Search Results: 1 - 10 of 176413 matches for " Juliana De Meis "
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Dynamics of Lymphocyte Populations during Trypanosoma cruzi Infection: From Thymocyte Depletion to Differential Cell Expansion/Contraction in Peripheral Lymphoid Organs
Alexandre Morrot,Juliana Barreto de Albuquerque,Luiz Ricardo Berbert,Carla Eponina de Carvalho Pinto,Juliana de Meis,Wilson Savino
Journal of Tropical Medicine , 2012, DOI: 10.1155/2012/747185
Abstract: The comprehension of the immune responses in infectious diseases is crucial for developing novel therapeutic strategies. Here, we review current findings on the dynamics of lymphocyte subpopulations following experimental acute infection by Trypanosoma cruzi, the causative agent of Chagas disease. In the thymus, although the negative selection process of the T-cell repertoire remains operational, there is a massive thymocyte depletion and abnormal release of immature CD4+CD8+ cells to peripheral lymphoid organs, where they acquire an activated phenotype similar to activated effector or memory T cells. These cells apparently bypassed the negative selection process, and some of them are potentially autoimmune. In infected animals, an atrophy of mesenteric lymph nodes is also observed, in contrast with the lymphocyte expansion in spleen and subcutaneous lymph nodes, illustrating a complex and organ specific dynamics of lymphocyte subpopulations. Accordingly, T- and B-cell activation is seen in subcutaneous lymph nodes and spleen, but not in mesenteric lymph nodes. Lastly, although the function of peripheral CD4+CD8+ T-cell population remains to be defined in vivo, their presence may contribute to the immunopathological events found in both murine and human Chagas disease. 1. Introduction Trypanosoma cruzi is the causative agent of Chagas disease affecting more than 10 million people in Latin America. The parasite is transmitted by feces of infected insect vectors belonging to the family Reduviidae [1–3]. After infection, the initial acute phase of the disease progresses to an asymptomatic indeterminate period with virtually undetectable parasitemia and a strong humoral and cellular anti-T. cruzi responses. Up to several years after the initial infection, approximately 20 to 30% of all infected individuals develop a chronic inflammatory disease primarily affecting the heart [2–4]. Although different mechanisms have been proposed to trigger this pathology, there is a growing body of evidence that parasite persistence is associated with a chronic inflammatory response, which is the primary cause of Chagas disease [5, 6]. Experimental models of T. cruzi infection have been widely used to study various aspects of the infection. Acute infection in mice leads to strong activation of innate and adaptive immune response [7, 8]. In the course of infection, there is a fine change in the dynamics on the size of lymphocyte populations that contributes to regional specificities of the immune response in central and peripheral lymphoid organs: while there is an expansion
Differential Regional Immune Response in Chagas Disease
Juliana de Meis ,Alexandre Morrot,Désio Aurélio Farias-de-Oliveira,Déa Maria Serra Villa-Verde,Wilson Savino
PLOS Neglected Tropical Diseases , 2009, DOI: 10.1371/journal.pntd.0000417
Abstract: Following infection, lymphocytes expand exponentially and differentiate into effector cells to control infection and coordinate the multiple effector arms of the immune response. Soon after this expansion, the majority of antigen-specific lymphocytes die, thus keeping homeostasis, and a small pool of memory cells develops, providing long-term immunity to subsequent reinfection. The extent of infection and rate of pathogen clearance are thought to determine both the magnitude of cell expansion and the homeostatic contraction to a stable number of memory cells. This straight correlation between the kinetics of T cell response and the dynamics of lymphoid tissue cell numbers is a constant feature in acute infections yielded by pathogens that are cleared during the course of response. However, the regional dynamics of the immune response mounted against pathogens that are able to establish a persistent infection remain poorly understood. Herein we discuss the differential lymphocyte dynamics in distinct central and peripheral lymphoid organs following acute infection by Trypanosoma cruzi, the causative agent of Chagas disease. While the thymus and mesenteric lymph nodes undergo a severe atrophy with massive lymphocyte depletion, the spleen and subcutaneous lymph nodes expand due to T and B cell activation/proliferation. These events are regulated by cytokines, as well as parasite-derived moieties. In this regard, identifying the molecular mechanisms underlying regional lymphocyte dynamics secondary to T. cruzi infection may hopefully contribute to the design of novel immune intervention strategies to control pathology in this infection.
Trypanosoma cruzi Entrance through Systemic or Mucosal Infection Sites Differentially Modulates Regional Immune Response Following Acute Infection in Mice
Juliana de Meis,Juliana Barreto de Albuquerque,Danielle Silva dos Santos,Désio Aurélio Farias-de-Oliveira,Luiz Ricardo Berbert,Vinícius Cotta-de-Almeida
Frontiers in Immunology , 2013, DOI: 10.3389/fimmu.2013.00216
Abstract: Acute Chagas disease is characterized by a systemic infection that leads to the strong activation of the adaptive immune response. Outbreaks of oral contamination by the infective protozoan Trypanosoma cruzi are frequent in Brazil and other Latin American countries, and an increased severity of clinical manifestations and mortality is observed in infected patients. These findings have elicited questions about the specific responses triggered after T. cruzi entry via mucosal sites, possibly modulating local immune mechanisms, and further impacting regional and systemic immunity. Here, we provide evidence for the existence of differential lymphoid organ responses in experimental models of acute T. cruzi infection.
Energy interconversion by the sarcoplasmic reticulum Ca2+-ATPase: ATP hydrolysis, Ca2+ transport, ATP synthesis and heat production
MEIS, LEOPOLDO DE;
Anais da Academia Brasileira de Ciências , 2000, DOI: 10.1590/S0001-37652000000300010
Abstract: the sarcoplasmic reticulum of skeletal muscle retains a membrane bound ca2+-atpase which is able to interconvert different forms of energy. a part of the chemical energy released during atp hydrolysis is converted into heat and in the bibliography it is assumed that the amount of heat produced during the hydrolysis of an atp molecule is always the same, as if the energy released during atp cleavage were divided in two non-interchangeable parts: one would be converted into heat, and the other used for ca2+ transport. data obtained in our laboratory during the past three years indicate that the amount of heat released during the hydrolysis of atp may vary between 7 and 32 kcal/mol depending on whether or not a transmembrane ca2+ gradient is formed across the sarcoplasmic reticulum membrane. drugs such as heparin and dimethyl sulfoxide are able to modify the fraction of the chemical energy released during atp hydrolysis which is used for ca2+ transport and the fraction which is dissipated in the surrounding medium as heat.
Cultura e empowerment: promo??o à saúde e preven??o da Aids entre prostitutas no Rio de Janeiro
Meis,Carla De;
Ciência & Saúde Coletiva , 2011, DOI: 10.1590/S1413-81232011000700079
Abstract: this paper discusses the difficulties that can arise when health promotion projects are developed within marginalized groups. this could be documented using the example of aids prevention among prostitutes. we applied questionnaires and focus group interviews were performed with prostitutes in mangue, rio de janeiro in 1989. later, during the decade of 1990, we accomplished open interviews with prostitutes who frequented s?o jo?o square in niterói and with the leaders of the prostitutes' movement of rio de janeiro. during the analysis of the interviews we observed that although, from a public health point of view, prostitutes are considered as a group, they seldom represent themselves in this way. in other words, while the goal of health promotion agencies and the prostitute' movement is to build a prostitutes' grassroots movement able to organize and fight for prostitutes' rights and citizenship, most of the subjects studied believed that prostitution was an evil activity and consequently created narratives which denied their belonging to the prostitutes' community.
Energy interconversion by the sarcoplasmic reticulum Ca2+-ATPase: ATP hydrolysis, Ca2+ transport, ATP synthesis and heat production
MEIS LEOPOLDO DE
Anais da Academia Brasileira de Ciências , 2000,
Abstract: The sarcoplasmic reticulum of skeletal muscle retains a membrane bound Ca2+-ATPase which is able to interconvert different forms of energy. A part of the chemical energy released during ATP hydrolysis is converted into heat and in the bibliography it is assumed that the amount of heat produced during the hydrolysis of an ATP molecule is always the same, as if the energy released during ATP cleavage were divided in two non-interchangeable parts: one would be converted into heat, and the other used for Ca2+ transport. Data obtained in our laboratory during the past three years indicate that the amount of heat released during the hydrolysis of ATP may vary between 7 and 32 Kcal/mol depending on whether or not a transmembrane Ca2+ gradient is formed across the sarcoplasmic reticulum membrane. Drugs such as heparin and dimethyl sulfoxide are able to modify the fraction of the chemical energy released during ATP hydrolysis which is used for Ca2+ transport and the fraction which is dissipated in the surrounding medium as heat.
Thymus Atrophy and Double-Positive Escape Are Common Features in Infectious Diseases
Juliana de Meis,Désio Aurélio Farias-de-Oliveira,Pedro H. Nunes Panzenhagen,Naiara Maran,Déa Maria Serra Villa-Verde,Alexandre Morrot,Wilson Savino
Journal of Parasitology Research , 2012, DOI: 10.1155/2012/574020
Abstract: The thymus is a primary lymphoid organ in which bone marrow-derived T-cell precursors undergo differentiation, leading to migration of positively selected thymocytes to the T-cell-dependent areas of secondary lymphoid organs. This organ can undergo atrophy, caused by several endogenous and exogenous factors such as ageing, hormone fluctuations, and infectious agents. This paper will focus on emerging data on the thymic atrophy caused by infectious agents. We present data on the dynamics of thymus lymphocytes during acute Trypanosoma cruzi infection, showing that the resulting thymus atrophy comprises the abnormal release of thymic-derived T cells and may have an impact on host immune response. 1. Introduction The thymus is a primary lymphoid organ in which bone marrow-derived T-cell precursors undergo differentiation, leading to migration of positively selected thymocytes to the T-cell-dependent areas of secondary lymphoid organs [2]. Interactions between thymocytes and specialized thymic microenvironmental cells (thymic epithelial cells, macrophages, dendritic cells, and fibroblasts) support and drive T-cell differentiation from bone marrow-derived precursors, by means of a series of interactions including receptor/coreceptor interactions, cytokines, chemokines, and hormones [3–7], as illustrated in Figure 1. Figure 1: Intrathymic differentiation of T cells. Lymphocyte differentiation initiates when T-cell precursors enter the thymus through postcapillary venules located at corticomedullary junction. After entering the organ, cells interact with the thymic microenvironment (thymic epithelial cells, macrophages, dendritic cells, and fibroblasts), which ultimately lead to their proliferation and TCR rearrangement. Interactions between thymocytes and specialized thymic microenvironmental cells support and direct T cell differentiation by means of a series of interactions including receptor/coreceptor interactions (MHC-TCR, Integrin/ECM Proteins), cytokines (IL-1, IL-2, IL-3, IL-6, IL-7, IL-8, IFN-gamma), chemokines (as CCL25, CXCL12, CCL21), and hormones, with corresponding receptors. At the subcapsular zone, these thymocytes undergo TCR beta chain rearrangement and selection. Double-positive thymocytes migrate through the cortex and initiate TCR testing (positive selection). Positively selected thymocytes, located at the medulla, are screened for self-reactivity through negative selection. Residence in the medulla is followed by emigration, which is regulated by sphingosine-1-phosphate and its receptor (S1P1). Adapted from [ 1]. Thymopoiesis starts at
Indícios de varia es climáticas neo-quaternárias no médio vale do Rio Doce
Maria Regina Mousinho de Meis
Anuário do Instituto de Geociências , 1977,
Abstract:
Avalia??o da produ??o científica dos principais periódicos brasileiros de psiquiatria no período de 1981 a 1995
Figueira, Ivan;Leta, Jacqueline;De Meis, Leopoldo;
Revista Brasileira de Psiquiatria , 1999, DOI: 10.1590/S1516-44461999000400008
Abstract: the present study analyses a total of 1,016 articles published in the period of 1981-1995 in different brazilian psychiactric journals named, the jornal brasileiro de psiquiatria (n=1016), the revista brasileira de psiquiatria (n=375), and the revista de psiquiatria clínica (n= 83). the articles were classified according to type, field, topic, disorders and research design. it was found that the review and opinion articles were the most frequent publications. articles classified as research represented 26% of the total publications and has been growing at the rate of 4% per 5-year period. articles described as case-control, prospective and randomized clinical trials were scarce. there were a reduced number of articles dealing with bipolar disorder (2.4% of the total articles), and cocaine use disorder (0.3% of total articles), two conditions of great social impact.
Avalia o da produ o científica dos principais periódicos brasileiros de psiquiatria no período de 1981 a 1995
Figueira Ivan,Leta Jacqueline,De Meis Leopoldo
Revista Brasileira de Psiquiatria , 1999,
Abstract: No presente trabalho foram analisados os artigos do Jornal Brasileiro de Psiquiatria (n= 1016), da Revista Brasileira de Psiquiatria (n = 375) e da Revista de Psiquiatria Clínica (n = 83) de 1981 a 1995, classificando-os quanto ao tipo, campo, tópico, transtorno, desenho de pesquisa e endere o das institui es. Observou-se que os artigos classificados como revis o e opini o foram os tipos mais freqüentes e que o número de artigos de pesquisa, que representou 26% do total dos artigos publicados, tem crescido à taxa de 4% por qüinqüênio. Dentre os artigos de pesquisa, os estudos do tipo caso-controle, prospectivos e ensaios randomizados controlados foram pouco freqüentes. Quanto aos transtornos, verificou-se que pouco se publicou em algumas áreas clínicas importantes, tais como as relacionadas ao transtorno bipolar e ao de uso da cocaína, que representaram 2,4% e 0,3% do total de artigos.
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