Salmonella enterica serovar Typhimurium (S. typhimurium) is a gram-negative bacteria capable of infecting a variety of warm-blooded vertebrate hosts. In humans, consumption of S. typhimurium through contaminated food or water typically leads to an acute but self-limiting gastroenteritis and oftentimes an enlargement of the spleen (splenomegaly). Splenomegaly has been attributed to the expansion of phagocytes, B and T lymphocytes, and immature CD71+Ter119+ red blood cells (RBCs). The spleen is an important organ with distinct roles in RBC recycling, the capture of blood-borne pathogens, and as a site of initiation of the adaptive immune response. The spleen has a characteristic tissue architecture composed of three compartments. The white pulp (WP), largely populated by B and T lymphocytes is surrounded by the red pulp (RP), which primarily contains F4/80+ macrophages. The border between the WP and RP, the marginal zone (MZ), is populated by MOMA+ and MARCO+ macrophages which are important for the capture of blood-borne pathogens. This precise organization of the spleen allows for efficient antigen capture and activation of adaptive immunity, due to the close proximity of antigen presenting cells and lymphocytes. It is known that Salmonella spp. infections delay the adaptive immune response in comparison to other bacteria, such as Listeria monocytogenes. Therefore, we investigated the effect of an attenuated S. typhimurium strain (÷9088) on in situ splenic organization. We utilized four-color immunofluorescence microscopy (IFM) in combination with flow cytometry to characterize the in situ changes of spleen architecture and cell population profiles during S. typhimurium infection in mice. Within the first week of infection, splenomegaly is evident and after three weeks of infection, the spleen comprises over 5% of the mouse's total body weight. During this time S. typhimurium has not been cleared from the spleen and mice are anemic with decreased pack cell volume. We confirmed previous studies that reported extramedullary erythropoiesis was a major cause of splenomegaly. However, we also show that RP F4/80+ macrophages significantly expand and take over the WP regions of the spleen, increasingly co-localizing with immature (CD71+Ter119+) and mature (CD71-Ter119+) RBC subsets. As a result of these dramatic changes in cell proportions and their in situ distribution, the splenic architecture becomes unrecognizable. The boundary between WP and RP is lost as proportions of MOMA+ macrophages of the MZ are reduced following infection. Likewise, B and T cell zones of the WP are also drastically reduced, most likely due to their increased co-localization with F4/80+ macrophages. As a result of infection, the increased cellularity of splenomegaly results in changing proportions of cell populations, potentially disrupting the link between infection and immune response. Together, these data provide further insight into the disease process of S. typhimurium infection in mice. Understanding how the changes in splenic architecture affect the adaptive immune response has implications for the design of more effective Salmonella-based vaccines and therapies.

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Orientador: Gabriel Hessel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T01:34:39Z (GMT). No. of bitstreams: 1 Alcantara_RobertaVacaride_M.pdf: 1862870 bytes, checksum: 32d187590b43696d2d46904761c03058 (MD5) Previous issue date: 2007 / Resumo: A trombose de veia porta (TVP) é uma importante causa de hipertensão portal na faixa etária pediátrica (FEP). As principais formas de apresentação clínica são hemorragia digestiva alta (HDA) e esplenomegalia. Há pouca informação sobre a evolução dessa doença em crianças. O objetivo desse estudo foi avaliar a evolução clínica, laboratorial, ultra-sonográfica e endoscópica de pacientes com TVP na FEP. Foi realizado um estudo descritivo e longitudinal de 51 pacientes com TVP sem doença hepática crônica associada acompanhados no Ambulatório de Hepatologia Pediátrica do Hospital de Clínicas da Faculdade de Ciências Médicas da Universidade Estadual de Campinas entre janeiro de 1986 e junho de 2006. Elaborou-se uma ficha de coleta de dados, a partir dos prontuários dos pacientes incluídos, que constou dos seguintes itens: identificação e avaliações clínica, laboratorial, ultra-sonográfica e endoscópica. Da avaliação laboratorial, foram obtidos os resultados dos seguintes exames: eritrograma, leucograma, contagem de plaquetas, RNI e R. Foram selecionados os resultados dos primeiros e últimos exames realizados, e os que foram coletados próximo ao ultra-som de abdome em que havia o resultado da dimensão do baço. A análise estatística foi descritiva para os indicadores clínicos e, para análise das variáveis, foram empregados os testes de McNemar, Mann-Whitney e coeficiente de correlação de Spearman. A análise de sobrevida dos pacientes foi realizada pelo método de Kaplan-Meier. Foi adotado nível de significância de 5%. HDA e esplenomegalia foram as principais formas de apresentação clínica que justificaram o encaminhamento para investigação, com freqüência de 66% e 22%, respectivamente. As medianas da idade do início dos sintomas foi de 3,7 anos e do tempo de seguimento foi de 4,8 anos. O fator de risco (FR) associado à TVP não foi identificado na maioria dos casos. Quando identificado, o mais freqüente foi o cateterismo umbilical (27,5%). A freqüência da HDA foi alta na admissão (66%) e na evolução (78%). A esplenomegalia já estava presente ao exame físico em 83,7% dos casos na admissão. A maioria dos pacientes apresentava níveis séricos de aminotransferases normais e alta freqüência de anemia, leucopenia e plaquetopenia. Com a evolução, observaram-se melhora da anemia e persistência da leucopenia e da plaquetopenia. A comparação entre a dimensão esplênica e a contagem de leucócitos, plaquetas e valores de R mostrou diferença estatística, sendo inversamente proporcional para o número de leucócitos e de plaquetas e diretamente proporcional para o R. Cinqüenta pacientes foram submetidos à endoscopia digestiva. Ao diagnóstico, 88% dos pacientes apresentavam varizes de esôfago (VE), 50% varizes gástricas (VG) e 22% gastropatia da hipertensão portal (GHP). As últimas endoscopias evidenciaram VE em 73%, VG em 60% e GHP em 41% dos pacientes. Escleroterapia e/ou ligadura de varizes esofágicas foram realizadas em 41 pacientes, sendo a maioria dos procedimentos realizados no primeiro semestre após o início da terapia endoscópica (p<0,001). Biliopatia portal foi diagnosticada em 4 pacientes. Três pacientes foram submetidos a shunt porto-sistêmico. Evolução para óbito ocorreu em 3 pacientes. Em conclusão, HDA, esplenomegalia e hiperesplenismo devem alertar o médico para o diagnóstico de TVP. A maioria dos casos permanece sem FR conhecido. O sangramento digestivo ocorreu na maior parte dos pacientes e motivou múltiplas transfusões. A doença apresenta baixa mortalidade, mas alta morbidade / Abstract: The aim of this study was to analyze clinical, laboratory, ultrasonographic and endoscopic data of PVT in children. We comprised 51 children who had PVT diagnosed between January 1986 and January 2006. All of them were selected from the record of patients admitted to the Hepatology Pediatric Outpatient Clinic of the University of Campinas Teaching Hospital (Unicamp), city of Campinas, state of São Paulo, Brazil. The information obtained from the patients¿ charts included their clinical, laboratory, ultrasonographic and endoscopic data. The following values were included in the laboratory evaluation: hemoglobin, white blood cell and platelet counts, INR and R values. The first and last results of these exams were selected, as well as those exams performed next to an abdominal ultrasonography in which the spleen dimension was available. The clinical data were obtained from descriptive statistical analysis. The Mann-Whitney and McNemar tests and Spearman¿s rank correlation coefficient were used for variable data. Kaplan-Meier¿s method was used in order to determine patient¿s life expectancy. A p-value of <0.05 was considered signif icant. Initial manifestations included gastrointestinal bleeding and splenomegaly, seen in 66% and 22% of the patients, respectively, with a median age of 3.7 years old. The patients were followed for a median time of 4.8 years. The etiologic factor for PVT was not available in most patients and umbilical catheterization was identified in 27.5% of all cases. Sixty percent of the patients presented with GI bleeding at the first medical evaluation and 78% of them had presented GI bleeding at the last one. Splenomegaly was the most frequent sign at physical examination, occurring in 83.7% of the children at presentation. Most patients had normal liver enzymes, but low levels of hemoglobin, leukocytes and platelet counts were commonly seen. The last evaluation showed persistent leucopenia and low platelet count. The correlation between the spleen dimension and the white blood cell count, platelet count and R was statistically significant. Fifty patients underwent upper gastrointestinal endoscopy. At first evaluation, 88% of the patients presented with esophageal varices, 50% with gastric varices and 22% with portal hypertensive gastropathy. The last endoscopies showed esophageal varices in 73%, gastric varices in 60% e portal hypertensive gastropathy in 41%. Forty-one patients underwent sclerotherapy and/or esophageal ligation, most of whom during the first 6-month period after they were initiated (p < 0.001). Portal biliopathy occurred in four patients. Shunt surgery was performed in three patients. Three patients died. In conclusion: Gastrointestinal bleeding, splenomegaly and hypersplenism should alert physicians to PVT. The etiologic factor related to PVT remains uncertain in most cases. The majority of patients experienced gastrointestinal bleeding and many blood transfusions. Therefore, PVT seems to cause little mortality but high morbidity / Mestrado / Pediatria / Mestre em Saude da Criança e do Adolescente

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Orientador: Gabriel Hessel / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-20T13:44:33Z (GMT). No. of bitstreams: 1 Alcantara_RobertaVacaride_D.pdf: 665519 bytes, checksum: b1cdfc8920d36cc06cf754f99e2c24af (MD5) Previous issue date: 2012 / Resumo: Objetivo: Identificar preditores não invasivos de varizes esofágicas em crianças e adolescentes com hepatopatia crônica e obstrução extra-hepática da veia porta (OEHVP). Casuística e métodos: Estudo prospectivo que incluiu 53 crianças e adolescentes com hepatopatia crônica ou OEHVP, sem antecedente de hemorragia digestiva ou tratamento de varizes esofágicas (VE), com até 20 anos de idade. Dois grupos foram formados: grupo I (35 pacientes com hepatopatia crônica) e grupo II (18 com OEHVP). Foram realizados hemograma, RNI, albumina, bilirrubina total, ultrassonografia de abdome e endoscopia digestiva alta. O índice esplênico (IE) foi determinado dividindo a dimensão longitudinal do baço pelo limite superior dos valores de referência da literatura. As variáveis foram comparadas quanto à presença ou não de VE, varizes gástricas (VG) e gastropatia da hipertensão portal (GHP) através de análise univariada (? ², exato de Fischer e Wilcoxon) e multivariada (regressão logística). A acurácia foi determinada a partir da área sob a curva ROC. Resultados: As VE foram observadas em 48,5% dos pacientes do grupo I e em 83,3% do grupo II. Plaquetopenia (p=0,0015), esplenomegalia (p=0,0003), razão plaquetas/IE (p=0,0007), presença de shunt esplenorrenal (p=0,0329) e a espessura do ligamento venoso (p=0,0151) se mostraram indicadores preditivos de VE entre os pacientes do grupo I. Após análise multivariada, a plaquetopenia (odds=21,7) se manteve um indicador independente da presença de VE entre os pacientes com hepatopatia crônica. Entre os pacientes do grupo II observou-se diferença estatística quanto à presença de varizes na vesícula (p=0,0245) e espessura da parede da vesícula biliar (p=0,0289). O número de plaquetas (p=0,0369), o IE (p=0,0041) e a razão plaquetas/IE (p=0,0192) se mostraram indicativos de VG entre os pacientes do grupo I. A presença de plaquetopenia foi maior entre os pacientes do grupo II com VG (p=0,0216). GHP foi estatisticamente maior entre os pacientes do grupo I com plaquetopenia (p=0,0286), presença de shunt esplenorrenal (p=0,0384), menor razão plaquetas/IE (p=0,0369) e maior espessura do ligamento venoso (p=0,0226). Conclusões: O número de plaquetas, o índice esplênico, a razão plaquetas/IE, a presença de shunt esplenorrenal e a espessura do ligamento venoso foram indicativos de VE entre os pacientes com hepatopatia crônica. A presença de varizes na vesícula e maior espessura da parede da vesícula foram indicativos de VE entre os pacientes com OEHVP. Plaquetopenia, esplenomegalia e menor razão plaquetas/IE foram indicativos de VG entre os pacientes do grupo I. Plaquetopenia foi indicativa de VG entre os pacientes do grupo II. Plaquetopenia, presença de shunt esplenorrenal, RNI alargado, menor razão plaquetas/IE e maior espessura do ligamento venoso foram indicativos de GHP entre os pacientes com hepatopatia crônica / Abstract: Aim: Identify non-invasive predictors of esophageal varices in children and adolescents with chronic liver disease and extra hepatic portal venous obstruction (EHPVO). Casuistic and methods: Prospective evaluation of 53 patients younger than 20 with chronic liver disease or EHPVO and no history of bleeding or prophylactic treatment of esophageal varices (EV). They were divided in 2 groups: group I (35 with chronic liver disease) and group II (18 with EHPVO). Their blood count, INR, albumin, bilirubin, abdominal ultrasound and upper endoscopy results were taken. A splenic index (SI) was determined by dividing the patients' spleen dimension by its uppermost limit according to their age. The variables were compared to the presence of EV, gastric varices (GV) and portal hypertensive gastropathy (PHG). The univariate (?² test, Fischer's exact test and Wilcoxon rank sum test) and multivariate (logistic regression) analysis were performed. A ROC curve was constructed and the area under the ROC was calculated. Results: EV were observed in 48,5% of group I patients and in 83,3% of group II patients. Low platelet count (p=0,0015), splenomegaly (p=0,0003), SI (p=0,0007), splenorenal shunt (p=0,0329) and lesser omental thickness (p=0,0151) were statistically predictors of EV among group I patients. The multivariate analysis showed low platelet count (odds=21,7) as an independent predictor of EV in patients with chronic liver disease. Gallbladder varices (p=0,0245) and gallbladders' wall thickness (p=0,0289) statistically predicted EV among group II patients. Platelet count (p=0369), SI (p=0,0041) and platelet/SI ratio (p=0192) were significant predictors of GV among group I patients. Low platelet count predicted GV among group II patients (p=0,0216). PHG occurred more often among group I patients who had low platelet count (p=0,0286), splenorenal shunt (p=0,0384), lower platelet/SI ratio (p=0,0369) and thicker lesser omental thickness (p=0,0226). Conclusions: Platelet count, splenic index, platelet/SI ratio, splenorrenal shunt and lesser omental thickness were indicative of EV among children and adolescents with chronic liver disease. Gallbladder varices and thicker gallbladders' wall were indicative of EV among EHPVO patients. Low platelet count, splenomegaly and lesser platelet/SI ratio were indicative of GV among group I patients. Low platelet count was indicative of GV among group II patients. Low platelet count, splenorenal shunt, bigger INR, lesser platelet/SI ratio and thicker lesser omentum were indicative of PHG among chronic liver disease patients / Doutorado / Pediatria / Doutor em Saude da Criança e do Adolescente

Hepatitis E virus (HEV) is a major cause of enterically transmitted acute viral hepatitis in developing countries that lack proper hygienic infrastructure. Hepatitis E is globally distributed and has emerged as an important public health disease in both developing and industrialized countries. HEV is a non-enveloped virus carrying a single-stranded positive-sense RNA genome of approximately 7.200 bp in length. The life cycle of HEV is poorly understood due to the lack of an efficient cell culture system. Animal model systems, including non-human primates, swine, and chickens are being used to study some fundamental aspects of the HEV biology. Recently, novel animal strains of rat and rabbit HEV have been discovered, and whose usage as animal model systems needs to be established. HEV infections in pigs and chickens provide excellent model systems to study the replication and pathogenesis aspects of HEV. Recently, we identified a hypervariable region (HVR) in the open reading frame 1 (ORF1) of HEV. The objectives of this dissertation were to utilize chicken and swine model systems to study the role of HVR in HEV infection in vivo, to determine the effects of HVR on replication of HEV in vitro, and to analyze the effect of exchange of HVR among different genotypes on the replication-competency and virion production in vitro. Extensive sequence variability in the HVR among HEV strains of different genotypes prompted us to study the dispensability of this region. Initially we constructed two partial deletion mutants of genotype 1 human HEV, hHVRd1 and hHVRd2, with in-frame deletion of amino acids (aa) 711 to 777 and 747 to 761 in the HVR of a sub-genomic GFP HEV replicon. Expression of enhanced green fluorescent protein by the mutant hHVRd2 confirmed the dispensability of amino acid residues 747-761 of the HVR. To confirm our in vitro results, specific-pathogen-free (SPF) chickens were intra-hepatically inoculated with capped RNA transcripts from three avian HEV HVR-deletion mutants: mutants aHVRd1 (Δ557-585), aHVRd2 (Δ612-641), and aHVRd3 (Δ557-641). Chickens intra-hepatically inoculated with the mutants, aHVRd1 and aHVRd2, developed active viral infection as evidenced by seroconversion, viremia, and fecal virus shedding. Mutant aHVRd3, with a larger HVR deletion, was apparently attenuated in chickens. Additionally, we used the swine model system to further verify our results from the chicken study. The infectivity of four genotype 3 swine HEV HVR-deletion mutants, sHVRd1 (Δ712-790), sHVRd2 (Δ722-781), sHVRd3 (Δ735-765), and sHVRd4 (Δ712-765) constructed using the genotype 3 swine HEV as the backbone was determined in SPF pigs. Pigs intra-hepatically inoculated with capped RNA transcripts from the mutants sHVRd2, sHVRd3, and sHVRd4 developed active viral infection, whereas mutant sHVRd1 (Δ712-790), with a nearly complete HVR deletion, exhibited an attenuation phenotype. The data from these studies indicate that deletions in HVR do not abolish HEV infectivity in vitro or in vivo, although evidence for attenuation was observed for HEV mutants with a larger or nearly complete HVR deletion. To further elucidate the role of HVR in HEV replication, we investigated the effects of serial amino acid deletions in HVR on the replication of HEV. We first constructed a genotype 1 human HEV luciferase replicon by replacing the ORF2 gene that encodes for the capsid protein with the fire fly luciferase reporter gene. Using the backbone of human HEV genotype 1 luciferase replicon, we constructed a series of HVR-deletion mutants with deletions of variable lengths in the HVR. Amino acid deletions Δ711-725, 711-740 and Δ711-750 were engineered at the N-terminus, deletions Δ729-754, Δ721-766, and Δ716-771 were engineered in the central region, and deletions Δ761-775, Δ746-775, and Δ736-775 were engineered at C-terminus of the HVR. The effects of these serial deletions on HEV RNA replication in the human liver carcinoma cell line, Huh7, were examined. Replication levels of mutants carrying these deletions were compared with that of the wild-type HEV in Huh7 cells. We observed that deletions in the HVR did not abolish viral RNA synthesis but substantially reduced the replication levels of viral RNA, as measured by the reporter luciferase activity. To further verify the effects of HVR deletions on viral RNA replication as observed with the genotype 1 human HEV replicon, we subsequently used a genetically-distinct strain of HEV, avian HEV, and constructed an avian HEV sub-genomic luciferase replicon by substituting the ORF2 gene of avian HEV with the fire fly luciferase gene. Avian HEV HVR-deletion mutants Δ557-603, Δ566-595, and Δ573-587 were then engineered using the backbone of avian HEV luciferase replicon. The replication efficiency of the three deletion mutants of avian HEV in chicken liver hepatoma cell line, LMH, was evaluated. Compared with the wild-type avian HEV, the viral RNA synthesis of the avian HEV HVR-deletion mutants was considerably reduced by the HVR deletions. To analyze the impact of the complete HVR deletion on avian HEV infectivity, we constructed an avian HEV mutant with a deletion of the entire HVR region (aaΔ557-603) using the avian HEV infectious cDNA clone as the backbone. After confirming the viability of the complete HVR-deletion mutant in LMH cells, SPF chickens were intrahepatically inoculated with capped RNA transcripts generated from the mutant. None of the chickens inoculated with the complete HVR-deletion mutant showed evidence of HEV infection, indicating that drastic reduction in replication levels due to complete HVR deletion has resulted in the loss of virus infectivity. The results indicated that HVR may have critical residues that may interact with viral/and or host factors and modulate the replication efficiency of HEV. In the final part of the dissertation research, we sought to determine if the variable sequences of HVR are genotype-specific for in vitro virus replication. By using the genotype 1 human HEV as the backbone, we swapped the HVR of genotype 1 human HEV with the HVRs of the genotype 3 swine HEV and the distantly-related avian HEV to construct two inter-genotypic chimeras, pSKHEV2-Sw and pSKHEV2-Av. Similarly, by using the genotype 3 swine HEV as the backbone, the HVR of genotype 3 swine HEV was swapped with the HVR of genotype 1 human HEV to construct the chimera, pSHEV3-Hu. The viability of these chimeras was tested in Huh7 cells that are permissive for HEV replication. Immunofluorescence assay (IFA) with anti-HEV antibodies revealed that all the three chimeras were replication-competent in Huh7 cells. The infectivity of these chimeras was subsequently evaluated in HepG2 cells. The results showed that exchange of the HVR between different genotypes of mammalian HEVs does not abolish the replication competency and infectivity of HEV. This finding suggests that HVR is not genotype-specific with respect to viral replication and infectivity. The absence of detectable viral antigen in HepG2 cells infected with chimera pSKHEV2-Av suggested a functional incompatibility of the HVR of avian HEV in the mammalian HEV genome. In summary, we identified a highly variable sequence, HVR, in the ORF1 of the HEV genome, and the sequences of the HVR vary significantly among HEV strains of different genotypes. We found that the HVR contain sequences that are dispensable for virus infectivity both in vitro and in vivo. Deletion analysis of HVR revealed that the region may play a role in modulating the replication efficiency of HEV RNA by interacting with viral and/or host factors. Finally, we demonstrated that HVR is not genotype-specific for virus replication and the region can be functionally replaced between mammalian HEV genotypes for virus replication and virion production in vitro. The results from this dissertation research have important implications for better understanding the biology and mechanism of HEV replication and may aid in our efforts to eventually develop a modified live-attenuated vaccine against HEV. / Ph. D.