Made available in DSpace on 2014-06-12T18:04:23Z (GMT). No. of bitstreams: 2 arquivo6195_1.pdf: 1143920 bytes, checksum: 0d0ca55cd7599cecc0ad08a953f1ec9b (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007 / O câncer apresenta-se como uma das grandes causa mortis na vida contemporânea, principalmente o de adulto que tem aumentado em função do aumento da expectativa de vida, mudança de hábitos alimentares e modo de vida. O câncer pediátrico está mais claramente relacionado a fatores genéticos herdados ou ligado a embriogênese. Os tipos mais prevalentes são as leucemias, os tumores do sistema nervoso e os linfomas. Os linfomas apresentam-se divididos em: doença de Hodgkin (HD) e linfomas não-Hodgkin (NHL), sendo o segundo responsável por mais da metade dos casos. Os NHL se destacam por várias características morfológicas, fenotípicas e por eventos moleculares que alteram a configuração cromossômica e a expressão de diversos genes, eventos moleculares estes que têm sido relacionados a vírus, porém de uma forma não muito clara e sem um modelo definitivo. No presente trabalho a relação entre a infecção por EBV, a transcrição de RNA do referido vírus e a superexpressão do proto-oncogene c-myc em amostras de linfoma foram estudadas. Analisamos biopsias de tumor de 49 pacientes, dos quais 34 (69,4%) eram do sexo masculino e 15 (31,6%) eram do sexo feminino. Os linfomas não-Hodgkin estudados eram de localização principalmente abdominal e em 63,4% o EBV foi detectado, com transcrição ativa do RNA viral em 29,3%. Já os linfomas de Hodgkin somaram apenas sete e em dois deles foi encontrada infecção por EBV. Nossos estudos indicam forte relação do EBV com o NHL, principalmente de localização abdominal, sendo necessários mais estudos da relação do vírus com a expressão elevada do proto-oncogene c-myc

Made available in DSpace on 2014-06-12T18:29:41Z (GMT). No. of bitstreams: 2 arquivo8032_1.pdf: 3953381 bytes, checksum: 360354bef4388c438bbaf203921213fe (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2005 / A infecção pelo Vírus da hepatite C (HCV) é um grave problema de saúde pública que atinge de 3% a 5% da população mundial, provocando hepatite crônica, cirrose hepática e hepatocarcinoma. Estudos oriundos da Itália, da Espanha e do Japão têm documentado haver associação entre o HCV e o desenvolvimento de doenças linfoproliferativas. Já é aceito pela comunidade científica o fato de haver uma associação entre a infecção pelo HCV e o desenvolvimento da crioglobulinemia mista essencial (que é uma proliferação de linfócitos B). E ainda há certo receio em acreditar que o HCV esteja diretamente envolvido na patogênese de alguns linfomas. Com o objetivo de avaliar a prevalência do HCV em pacientes com linfoma não-Hodgkin tipo-B, atendidos no Hospital das Clínicas UFPE, no período de janeiro de 2003 até dezembro de 2004, foram avaliados 178 pacientes com câncer divididos em dois grupos. O Grupo 1, foi constituído por 59 pacientes novos com linfoma não-Hodgkin tipo-B, e o grupo 2, por 119 pacientes com tumores sólidos (tumores não-hematológicos). Foram excluídos pacientes com sorologia positiva para HIV. A sorologia para HCV foi realizada pela técnica de ELISA de terceira geração. A prevalência do HCV em pacientes com linfoma não-Hodgkin tipo-B foi de 6,7%. Com um risco atribuído ao HCV estimado em 2,52 (CI95%= 1,54 4,11; p= 0,043). A freqüência do HCV em pacientes com tumores sólidos foi de 0,8% (razão de prevalência de 0,29; CI95%= 0,05 -1,70; p= 0,048). A freqüência do HIV em pacientes com LNH e tumores não-hematológico foi, respectivamente, de 1,6% e 2,5%. Este estudo mostrou uma maior freqüência da infecção pelo HCV em pacientes com linfoma não-Hodgkin tipo-B quando comparado com pacientes com tumores sólidos não-hematológico

Abstract The activity of neurons is critically dependent upon the suite of voltage-dependent ion channels expressed in their membranes. In particular, voltage-gated K+ channels are extremely diverse in their function, contributing to the regulation of distinct aspects of neuronal activity by shaping the voltage responses. In this study the role of K+ channels in neural coding is investigated in Drosophila photoreceptors by using biophysical models with parameters derived from the electrophysiological experiments. Due to their biophysical properties, the Shaker channels attenuate the fast transients and amplify the slower signal components, enabling photoreceptors to use their voltage range more effectively. Slow delayed rectifier channels, shown to be encoded by the Shab gene, activate at high light intensities, thereby attenuating the light-induced depolarization and preventing response saturation. Activation of Shab channels also reduces the membrane time constant making it possible to encode faster events. Interactions between the voltage-gated K+ channels and the currents generated by the light induced conductance (LIC) were investigated during naturalistic stimulation in wild type and Shaker mutant photoreceptors. It is shown that in addition to eliminating the Shaker current, the mutation increased the Shab current and affected the current flowing through the LIC. Part of these changes could be attributed to direct feedback from the Shaker channels via the membrane potential. However, it is suggested that also other changes may occur in the LIC due to mutation in K+ channels, possibly during photoreceptor development. Comparison of the Shaker and Shab mutant photoreceptors with the wild type revealed that a concurrent decrease in the steady-state input resistance followed from deletion of the voltage-gated K+ channels. This allowed partial compensation of the compression and saturation caused by the loss of Shaker channels and it maintained the characteristics of the light-voltage relationship in Shab mutant photoreceptors. However, wild type properties were not fully restored in either mutant. Indeed, decreased input resistance results in reduced efficiency of neural processing, assessed by the metabolic cost of information. Results of this study demonstrate the importance of the voltage-gated K+ channels for neural coding precision and highlight the robustness of neuronal information processing gained through regulation of the electrical properties.

Orientador: Carmino Antonio de Souza / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-07-20T11:39:18Z (GMT). No. of bitstreams: 1 Castro_MariadeLourdesRiosBarjasde_M.pdf: 3057293 bytes, checksum: 731f3b2dc9a23a327eca9d790f525f23 (MD5) Previous issue date: 1995 / Resumo: Estudou-se 77 pacientes adultos portadores de linfoma não Hodgkin (LNH) ao diagnóstico, atendidos no Hospital das Clínicas da Universidade Estadual de Campinas. Classificou-se os LNH histologicamente segundo Kiel. Clinicamente avaliou-se os pacientes através da história e do exame fisico e laboratorialmente pela análise do sangue periférico (hemo grama e contagem de reticulócitos), dosagem de bilirrubinas, urobilinogênio urinário e demais exames necessários ao estadiamento clínico. Estadiou-se os linfomas de acordo com os critérios propostos em Ann Arbor e as leucemias linfocíticas crônicas segundo Rai. Estudou-se os perfis imunohematológicos dos pacientes através dos seguintes testes: determinação de grupo sanguíneo ABO/Rh, teste direto da antiglobulina com soros poliespecífico (anti-IgG, anti-C3b e allti-C3d) e monoespecíficos (anti-IgG, anti-IgM, anti-C3, anti-C3d e anti-C4), pesquisa e identificação de anticorpos séricos pelas técnicas em tubo com polietilenoglicol, meio de baixa força iônica (LISS) e hemácias pré tratadas com enzimas e pela técnica de gel-centrifugação. Os resultados da avaliação imunohematológica dos pacientes portadores de LNH foram: 1. A freqüência de autoanticorpos anti-eritrocitários foi de 29,9% (provável auto anti-I e auto-IgG sem especificidade definida); 2. O quadro de hemólise clínica e laboratorial ocorreu em 1,3% dos pacientes; 3. Houve uma tendência dos linfomas de baixo grau de malignidade serem assocíados à presença de autoanticorpos anti-eritrocitários; 4. Não houve associação entre o tipo imunológico dos LNH (B e T) e do estadiamento clínico dos linfomas com a presença dos autoanticorpos. Conclui-se que a alta incidência de autoanticorpos anti-eritrocitários encontrada em nossa casuística provavelmente esteja relacionada com as alterações imunes próprias dos LNH / Abstract: Seventy-seven adult patients with non Hodgkin's lymphoma (NHL) were studied at the time of diagnosis at University Hospital of State University of Campinas from March 1992 to November 1993. Histological subgrouping of NHL was performed according to the Kiel criteria. All patients were characterized by clinical and laboratorial examination, which included cytology of peripheral blood, reticulocyte count, bilirubin, urinary urobilinogen, haptoglobin, exams for staging of lymphoma and immunohematologic evaluation. The patients were staged according to the principIes of the Ann Arbor classification and the cases of chronic lymphocytic leukemia according to Ray clinical staging system. Immunohematology investigation screenings were: determination of blood groups ABO/Rh, direct antiglobulin reaction with polyspecific antiglobulin reagents (anti-IgG, anti-Cb anti-C3d) and monospecific reagents (anti-IgG, anti-IgM, anti-C3, anti-C3d, anti-C4), detection ofblood groups antibodies in serum by indirect antiglobulin test (polyethylene glycol, low ionic strength solution and enzyme-treated ceUs). Whenever an antibody was found on screening, its specificity was determined using a suitable panel of red cells. 1. Our results of the immunohematological evaluation of the patients with NHL showed that: 1-There were 29.87% of the patients 'with autoantibodies against erythrocytes (IgM with probable specificity of auto anti-I and IgG with specificity serologically indlstinguishable), without clinical disorders; 2. The hemolytic anemia occurred in 1.29% of the patients. This value is compatible with the literature; 3. A weak correlation existed between the low grade lymphomas and erythrocyte autoantibodies; 4. No correlation existed between the type immunologic of lymphoma (B e T) and staging of NHL with erythrocyte auto antibodies. We have concluded that probably the high incidence of autoantibodies against erythrocytes would be related to the autoimmune derangements caused by non Hodgkin's lymphoma / Mestrado / Mestre em Clinica Medica

The efficacy of therapeutic modalities for non-Hodgkin’s lymphoma have been tested and improved throughout the 19th century through various series of drug trials aimed at eliminating cellular malignancies, first through chemotherapy treatment, and more recently through immunotherapy. While to an extent successful in eliminating cancerous lesions and affected cells, chemotherapy treatments have shown to influence the induction of new malignancies, through genetic mutation, as well as unwanted toxic effects of systemic poisoning. The purpose of this thesis is to compare treatment methods in terms of their biomolecular activity, precision of intended results, and possible drawbacks, as well as their application to specific populations of Non-Hodgkin lymphoma diagnoses, including Follicular and Diffuse Large B-Cell lymphomas. In the following sections on contributing factors specific to Diffuse Large B-Cell lymphomas and Follicular lymphoma, elements of disease prognosis will be analyzed from a molecular and clinical point of view. This includes a focus on the impact of genetic mutation, the immunohistochemical evidence these changes present, as well as the variances in immune cell functionality, and finally a description of symptoms with direction to specific underlying causes. An analysis of standard of care chemotherapy, and monoclonal antibody treatments will then be provided for each occurrence. The second segment will discuss novel techniques being developed for the treatment of lymphoma including but not limited to new monoclonal antibodies, synthetic lethality modulation, inhibition of selected chemokine receptors, DNA vector immunization for production of internal host antibodies, concepts of cell mediated bispecific antibody induced destruction, and new generations of Immunomodulatory drugs. With the recent development of cost effective sequencing technology, included is a discussion of the shift towards personalized medicine treatments, targeting appropriate phenotypic specific populations for optimal results, as it relates to therapies for Diffuse Large B-Cell lymphoma and Follicular lymphoma.

Neural oscillations, including rhythms in the beta1 band (12-20 Hz), are important in various cognitive functions. Often brain networks receive rhythmic input at frequencies different than their natural frequency, so understanding how neural networks process rhythmic input is important for understanding their function in the brain. In the current thesis we study a beta1 rhythm that appears in the parietal cortex, focusing on the way it interacts with other incoming rhythms, and the implications of this interaction for cognition. The main part of the thesis consists of two stand-alone chapters, both using as a basis a biophysical neural network model that has been previously proposed to model the parietal beta1 rhythm and validated with in vitro experiments. In the first chapter we use a reduced version of this model, in order to study its dynamics, applying both analytic and numerical methods from dynamical systems. We show that a cell can respond at the same time to two periodic stimuli of unrelated frequencies, firing in phase with one, but with a mean firing rate equal to the other, a consequence of general properties of the dynamics of the network. We next show numerically that the behavior of a different cell, which is modeled as a high-dimensional dynamical system, can be described in a surprisingly simple way, owing to a reset that occurs in the state space when the cell fires. The interaction of the two cells leads to novel combinations of properties for neural dynamics, such as mode-locking to an input without phase-locking to it. In the second chapter, we study the ability of the beta1 model to support memory functions, in particular working memory. Working memory is a highly distributed component of the brain's memory systems, partially based in the parietal cortex. We show numerically that the parietal beta1 rhythm can provide an anatomical substrate for an episodic buffer of working memory. Specifically, it can support flexible and updatable representations of sensory input which are sensitive to distractors, allow for a read-out mechanism, and can be modulated or terminated by executive input.

There have been many different studies performed in order to examine various properties of neurons. One of the most important properties of neurons is an ability to originate and propagate action potential. The action potential is a source of communication between different neural structures located in different anatomical regions. Many different studies use modeling to describe the action potential and its properties. These models mathematically describe physical properties of neurons and analyze and explain biological and electrochemical processes such as action potential initiation and propagation. Therefore, one of the most important functions of neurons is an ability to provide communication between different neural structures located in different anatomical regions. This is achieved by transmitting electrical signals from one part of the body to another. For example, neurons transmit signals from the brain to the motor neurons (efferent neurons) and from body tissues back to the brain (afferent neurons). This communication process is extremely important for a being to function properly. One of the most valuable studies in neuroscience was conducted by Alan Hodgkin and Andrew Huxley. In their work, Alan Hodgkin and Andrew Huxley used a giant squid axon to create a mathematical model which analyzes and explains the ionic mechanisms underlying the initiation and propagation of action potentials. They received the 1963 Nobel Prize in Physiology/Medicine for their valuable contribution to medical science. The Hodgkin and Huxley model is a mathematical model that describes how the action potential is initiated and how it propagates in a neuron. It is a set of nonlinear ordinary differential equations that approximates the electrical characteristics of excitable cells such as neurons and cardiomyocytes. This work focuses on modeling the Hodgkin and Huxley model using MATLAB extension - Simulink. This tool provides a graphical editor, customizable block libraries, and solvers for modeling and simulating dynamic systems. Simulink model is used to describe the mechanisms and underlying processes involved in action potential initiation and propagation.

In der vorliegenden Arbeit wurde das Vorkommen neu erworbener N-Glykosylierungsmotive in t(14;18)-positiven und -negativen FL der lokalisierten (FL I/II) und fortgeschrittenen Stadien (FL III/IV), sowie zum Zeitpunkt der Primärdiagnose und des Rezidivs untersucht. Dabei wurde der jeweilige Haupttumorklon mit Hilfe von „Next Generation Sequencing“ und unter Verwendung des „LymphoTrack® Assays“ in einer Serie von 68 kryoasservierten FL identifiziert 36 t(14;18)-negative und 32 t(14;18)-positive FL. Die Frequenz neu erworbener N-Glykosylierungsmotive unterschied sich signifikant zwischen t(14;18)-positiven und -negativen PD/R-FL III/IV, während man zwischen t(14;18)-positiven und -negativen PD/R-FL I/II keinen Unterschied beobachten konnte. Des Weiteren zeigten t(14;18)-negative PD/R-FL I-IV im Vergleich zu t(14;18)-positiven PD/R-FL I-IV signifikant häufiger einen Zugewinn neuer N-Glykosylierungsmotive in der FR3 Region des BCL2 Gens, sowie eine vermehrte Nutzung des IGHV4-34 Keimbahngens. Interessanterweise beschränkte sich die Nutzung des IGHV4-34 Gens auf PD-FL und konnte in R-FL nicht nachgewiesen werden. Da sowohl das Vorkommen neu erworbener N-Glykosylierungsmotive in FR3 als auch die Nutzung von IGHV4-34 im Zusammenhang mit Autoimmunerkrankungen beschrieben wurden, deuten unsere Ergebnisse darauf hin, dass die Subgruppe der t(14;18)-negativen FL im pathologischen Prozess der Onkogenese mehr auf die Stimulation durch (Auto)-Antigene als durch die Stimulation des B-Zell Rezeptors mit Lektinen (DC-SIGN) angewiesen sein könnte. / This study investigated the occurrence of newly acquired n-glycosylation motifs (NANGS) in a cohort of t(14;18)-positive and t(14;18)-negative FL, including early (I/II) and advanced (III/IV) stage treatment-naive and relapsed tumors. The clonotype was determined by using a next generation sequencing approach in a series of 68 FL with fresh frozen material [36 t(14;18) positive and 32 t(14;18) negative]. The frequency of NANGS differed considerably between t(14;18)-positive and t(14;18)-negative FL stage III/IV, but no difference was observed among t(14;18)-positive and t(14;18)-negative FL stage I/II. The introduction of NANGS in all t(14;18)- negative clinical subgroups occurred significantly more often in the FR3 region. Moreover, t(14;18)-negative treatment-naive FL, specifically those with NANGS, showed a strong bias for IGHV4-34 usage compared with t(14;18)-positive treatment-naive cases with NANGS; IGHV4-34 usage was never recorded in relapsed FL. In conclusion, subgroups of t(14;18)- negative FL might use different mechanisms of B-cell receptor stimulation compared with the lectin-mediated binding described in t(14;18)-positive FL, including responsiveness to autoantigens as indicated by biased IGHV4-34 usage and strong NANGS enrichment in FR3.

No / It is known that cells within the inflammatory background in classical Hodgkin lymphoma (cHL) provide signals essential for the continual survival of the neoplastic Hodgkin and Reed-Sternberg (HRS) cells. However, the mechanisms underlying the recruitment of this inflammatory infiltrate into the involved lymph nodes are less well understood. In this study, we show in vitro that HRS cells secrete lymphotoxin-α (LTα) which acts on endothelial cells to upregulate the expression of adhesion molecules that are important for T cell recruitment. LTα also enhances the expression of hyaluronan which preferentially contributes to the recruitment of CD4+ CD45RA+ naïve T cells under in vitro defined flow conditions. Enhanced expression of LTα in HRS cells and tissue stroma; and hyaluronan on endothelial cells are readily detected in involved lymph nodes from cHL patients. Our study also shows that although NF-κB and AP-1 are involved, the cyclooxygenase (COX) pathway is the dominant regulator of LTα production in HRS cells. Using pharmacological inhibitors, our data suggest that activity of COX1, but not of COX2, directly regulates the expression of nuclear c-Fos in HRS cells. Our findings suggest that HRS cell-derived LTα is an important mediator that contributes to T cell recruitment into lesional lymph nodes in cHL.

O linfoma de células do manto é associado à translocação t(11;14)(q13;q32) e à hiperexpressão da ciclina D1. Os pacientes com linfoma de células do manto apresentam-se com doença avançada ao diagnóstico e a fase leucêmica da doença é observada em cerca de um terço dos casos. Os linfócitos B virgens pré-centro germinativo, que ocupam a zona do manto dos folículos linfóides secundários, constituem a origem celular do linfoma de células do manto. A hiperexpressão da ciclina D1, por si só, não é suficiente para a patogênese da neoplasia, e a elucidação das alterações moleculares adicionais poderá fundamentar novas estratégias terapêuticas. Nesse contexto, os métodos de estudo do perfil de expressão gênica em larga escala têm potencial para auxiliar na descoberta dessas alterações moleculares adicionais. Todavia, nos estudos que empregaram esses métodos até o momento, o material genético foi obtido de amostras de gânglios acometidos pelo tumor, que contêm uma proporção variável de células normais do estroma do tecido linfóide. Por isso, ainda não se sabe quais dos genes identificados como alterados no linfoma de células do manto são específicos das células linfomatosas, e quais são dependentes das células normais que perfazem o estroma do gânglio. Com o objetivo de elucidar as alterações moleculares do linfoma de células do manto em nível celular, realizamos um estudo comparativo entre o perfil de expressão gênica de células linfomatosas purificadas e de linfócitos B virgens, utilizando microarrays de oligonucleotídeos. Células linfomatosas e linfócitos B virgens (IgD+CD38±CD27-) foram purificados em colunas magnéticas a partir do sangue periférico de pacientes com linfoma de células do manto em fase leucêmica e de amígdalas de indivíduos normais, respectivamente (pureza > 95%). Três indivíduos foram selecionados em cada grupo e os experimentos foram realizados em duplicatas usando microarrays comerciais modelo CodeLink Human UniSet I, com 10.000 genes. Foram identificados 106 genes com variação de expressão maior do que três vezes, 63 deles induzidos e 43 reprimidos no linfoma de células do manto em relação aos linfócitos B virgens. Dez genes (seis induzidos e quatro reprimidos) foram selecionados para quantificação, por RT-PCR em tempo real, em amostras de sangue periférico de 21 pacientes com linfoma de células do manto em fase leucêmica, além de 14 pacientes com outras doenças linfoproliferativas crônicas e de sete indivíduos sem doenças neoplásicas. Os resultados dos experimentos com microarrays foram confirmados pela quantificação por RT-PCR em tempo real em todos os 10 genes selecionados e os valores de expressão do gene TLR1 obtidos por esse método demonstraram correlação significativa com a sobrevida dos pacientes com linfoma de células do manto. Além de identificar vários genes modulados no linfoma de células do manto em nível celular, este estudo também revelou a expressão aberrante de diversos genes relacionados à apoptose e às vias de sinalização PI3K/AKT, WNT e TGFβ. Esses resultados adicionam informações originais à patogênese molecular do linfoma de células do manto e apontam para vias específicas de sinalização molecular como potenciais alvos para novas abordagens terapêuticas. / Mantle cell lymphoma is associated with the translocation t(11;14)(q13;32) and overexpression of cyclin D1. Mantle cell lymphoma is predominantly disseminated at diagnosis and a frank leukemic phase is detected in one third of patients. The pre-germinal-center naive B-cells, which populate the mantle zone of the secondary lymphoid follicles, are the cells of origin of mantle cell lymphoma. Overexpression of cyclin D1 is not sufficient by itself to cause lymphoma, and a better understanding of the additional molecular lesions may provide insights toward new therapeutic approaches. In this context, large scale gene expression studies may be useful in the investigation of such additional molecular lesions. However, the great majority of mantle cell lymphoma cases studied by these methods to date had the genetic material harvested from lymph nodes, which have a variable proportion of normal cells from the lymphoid stroma. It is therefore not known how many genes identified as differentially expressed in mantle cell lymphoma by tumor versus normal experiments are cell-autonomous rather than dependent on the tumor microenvironment. To address this issue, we compared the gene expression profile of mantle cell lymphoma cells and normal naive B-cells using oligonucleotide microarrays. Lymphoma cells and naive B-cells (IgD+CD38±CD27-) were highly purified, by magnetic activated cell sorting, from the peripheral blood of patients with mantle cell lymphoma in the leukemic phase and from tonsils of normal individuals, respectively (purity > 95% in all samples). Three individuals were selected for each group and experiments were performed in replicates using the Amersham CodeLink Human UniSet I Bioarrays, with 10,000 genes. We identified 106 genes differentially expressed with a fold change of at least three-fold, 63 induced and 43 repressed in mantle cell lymphoma in comparison with naive B-cells. Ten genes were selected (six induced and four repressed in lymphoma cells) for quantification by real-time RT-PCR in non-purified peripheral blood samples from 21 patients with mantle cell lymphoma in the leukemic phase, as well as in 14 patients with other chronic lymphoproliferative diseases and seven normal individuals. Microarray results were confirmed by real-time RT-PCR for all selected genes and expression values of the TLR1 gene as quantified by this method showed significant correlation with patient survival in mantle cell lymphoma. In addition to the identification of several modulated genes in mantle cell lymphoma at cellular level, this study revealed that some genes functionally connected through apoptosis or the PI3K/AKT, WNT and TGFβ signaling pathways are aberrantly expressed in mantle cell lymphoma. These results add original data to the molecular pathogenesis of mantle cell lymphoma and point to specific molecular signaling pathways related to inhibition of apoptosis as potential targets for new therapeutic approaches.