RESUMO
The opportunistic pathogen Pseudomonas viridiflava colonizes > 50 agricultural crop species and is the most common Pseudomonas in the phyllosphere of European Arabidopsis thaliana populations. Belonging to the P. syringae complex, it is genetically and phenotypically distinct from well-characterized P. syringae sensu stricto. Despite its prevalence, we lack knowledge of how A. thaliana responds to its native isolates at the molecular level. Here, we characterize the host response in an A. thaliana - P. viridiflava pathosystem. We measured host and pathogen growth in axenic infections and used immune mutants, transcriptomics, and metabolomics to determine defense pathways influencing susceptibility to P. viridiflava infection. Infection with P. viridiflava increased jasmonic acid (JA) levels and the expression of ethylene defense pathway marker genes. The immune response in a susceptible host accession was delayed compared with a tolerant one. Mechanical injury rescued susceptibility, consistent with an involvement of JA. The JA/ethylene pathway is important for suppression of P. viridiflava, yet suppression capacity varies between accessions. Our results shed light on how A. thaliana can suppress the ever-present P. viridiflava, but further studies are needed to understand how P. viridiflava evades this suppression to spread broadly across A. thaliana populations.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Pseudomonas , Etilenos/metabolismo , Ciclopentanos/metabolismo , Oxilipinas/metabolismo , Doenças das Plantas/genética , Pseudomonas syringae/metabolismo , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Ácido Salicílico/metabolismoRESUMO
Capsular polysaccharide (CP) biosynthesis in Staphylococcus aureus is tightly controlled resulting in a heterogeneous phenotype within a population and CP being mainly detectable in nongrowing cells. Expression of the corresponding biosynthesis gene cluster is driven by one promoter element (Pcap ). Here, we demonstrate that Pcap contains a main SigB-dependent promoter. The SigB consensus motif overlaps with a previously described inverted repeat (IR) that is crucial for cap expression. The essentiality of the IR is derived from this region acting as a SigB binding site rather than as an operator site for the proposed cap activators RbsR and MsaB. Furthermore, Pcap contains an extensive upstream region harboring a weak SigA-dependent promoter and binding sites for cap repressors such as SaeR, CodY and Rot. Heterogeneous CP synthesis is determined by SigB activity and repressor binding to the upstream region. SigB dependency and regulation by the upstream repressors are also sufficient to explain the temporal gene expression pattern at the transcriptional level. However, CP synthesis remains growth phase-dependent even when transcription is rendered constitutive, suggesting additional posttranscriptional regulatory circuits. Thus, the interference of multiple repressors with SigB-dependent promoter activity as well as post-transcriptional mechanisms ensure the appropriate regulation of CP synthesis.
Assuntos
Polissacarídeos Bacterianos/biossíntese , Polissacarídeos Bacterianos/metabolismo , Staphylococcus aureus/genética , Cápsulas Bacterianas/metabolismo , Proteínas de Bactérias/metabolismo , Sítios de Ligação/genética , Regulação Bacteriana da Expressão Gênica/genética , Família Multigênica/genética , Óperon/genética , Polissacarídeos/metabolismo , Polissacarídeos Bacterianos/fisiologia , Regiões Promotoras Genéticas/genética , Ligação Proteica/genética , Proteínas Repressoras/metabolismo , Fator sigma/metabolismo , Infecções Estafilocócicas/metabolismo , Staphylococcus aureus/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica/genéticaRESUMO
Endogenous retroviruses (ERVs) are fossils left in our genome from retrovirus infections of the past. Their sequences are part of every vertebrate genome and their random integrations are thought to have contributed to evolution. Although ERVs are mainly silenced by the host genome, they have been found to be activated in multiple disease states, such as auto-inflammatory disorders and neurological diseases. However, the numerous copies in mammalian genomes and the lack of tools to study them make defining their role in health and diseases challenging. In this study, we identified eight copies of the zebrafish endogenous retrovirus zferv. We created and characterised the first in vivo ERV reporter line in any species. Using a combination of live imaging, flow cytometry and single-cell RNA sequencing, we mapped zferv expression to early T cells and neurons. Thus, this new tool identified tissues expressing ERV in zebrafish, highlighting a potential role of ERV during brain development and strengthening the hypothesis that ERV play a role in immunity and neurological diseases. This transgenic line is therefore a suitable tool to study the function of ERV in health and diseases.
Assuntos
Retrovirus Endógenos , Infecções por Retroviridae , Animais , Animais Geneticamente Modificados , Retrovirus Endógenos/genética , Mamíferos , Neurônios , Infecções por Retroviridae/genética , Peixe-Zebra/genéticaRESUMO
Introduction: One of the most important risk factors for hepatocellular carcinoma (HCC) is alcohol consumption: Studies in different populations suggest that the risk of liver disease could be associated with genetic variants of the enzymes involved in alcohol metabolism, such as alcohol dehydrogenase (ADH) and cytochrome P450 CYP2E1. Objective: To identify and characterize the allelic variants of ADH1B, ADH1C and CYP2E1 genes in Colombian patients with cirrhosis and/or HCC. Materials and methods: We included samples from patients attending the hepatology unit between 2005-2007 and 2014-2016 of a hospital in Medellin. Samples were genotyped using PCR-RFLP. We compared the results with two control groups and the 1000 Genomes Project database. Results: We collected 97 samples from patients with a diagnosis of cirrhosis and/or HCC. The two main risk factors were chronic alcohol consumption (18.6%) and cholangiopathies (17.5%). The most frequent genotypes in the study population were ADH1B*1/1 (82%), ADH1C*1/1 (59%), and CYP2E1*C/C (84%). Conclusions: This first study of polymorphisms in Colombian patients diagnosed with cirrhosis and/or HCC showed genotypes ADH1B*1/1, ADH1C*1/1 and CYP2E1*C/C as the most frequent. We found no significant differences in the genotype frequency between cases and controls. Further studies are necessary to explore the association between polymorphisms and the risk of end-stage liver disease from alcohol consumption.
Introducción. Uno de los principales factores de riesgo del carcinoma hepatocelular es el consumo crónico de alcohol. En estudios en diferentes poblaciones, se sugiere que las variantes genéticas de las enzimas que participan en el metabolismo del alcohol, como la alcohol deshidrogenasa (ADH) y la citocromo P450 (CYP2E1), estarían asociadas con riesgo de enfermedades hepáticas terminales.Objetivo. Identificar y caracterizar las variantes alélicas de los genes ADH1B, ADH1C y CYP2E1 en pacientes colombianos con diagnóstico de cirrosis y carcinoma hepatocelular.Materiales y métodos. Se incluyeron muestras de pacientes atendidos entre el 2005 y el 2007, y entre el 2014 y el 2016, en la unidad de hepatología de un hospital de Medellín. La genotipificación de las muestras se hizo mediante reacción en cadena de la polimerasa (Polymerase Chain Reaction, PCR) con análisis de los polimorfismos en la longitud de los fragmentos de restricción (Restriction Fragment Length Polymorphism, RFLP). Los resultados se compararon con los de dos grupos de control y con lo reportado en la base de datos del 1000 Genomes Project.Resultados. Se recolectaron 97 muestras de pacientes con diagnóstico de cirrosis y carcinoma hepatocelular. Los dos factores de riesgo más frecuentes fueron el consumo crónico de alcohol (18,6 %) y las colangiopatías (17,5 %). Los genotipos más frecuentes en la población de estudio fueron el ADH1B*1/1 (82 %), el ADH1C*1/1 (59 %) y el CYP2E1*C/C (84 %).Conclusiones. En este primer estudio de los polimorfismos en pacientes colombianos con diagnóstico de cirrosis y carcinoma hepatocelular, los genotipos más frecuentes fueron el ADH1B*1/1, el ADH1C*1/1 y el CYP2E1*C/C. No se observaron diferencias estadísticamente significativas en la frecuencia de los genotipos entre los casos y los controles. Se requieren estudios adicionales en población colombiana para evaluar el riesgo de la enfermedad hepática terminal por consumo crónico de alcohol y laasociación con los polimorfismos.
Assuntos
Álcool Desidrogenase/genética , Carcinoma Hepatocelular/genética , Citocromo P-450 CYP2E1/genética , Cirrose Hepática/genética , Neoplasias Hepáticas/genética , Polimorfismo Genético , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Hepatitis E virus (HEV) is one of the main causes of acute viral hepatitis of enteric transmission. HEV has been detected in environmental samples in several countries from Europe and Asia, constituting a risk factor for waterborne infection. In Colombia, HEV has been identified in samples obtained from patients as well as from swine, but no environmental studies have been carried out. To determine if HEV is present in environmental waters, samples from the main source of drinking water plant and of wastewater system of eight municipalities and two villages of Antioquia state (North West Colombia), were collected between December 2012 and April 2014. The HEV genome was detected by RT-PCR in 23.3% (7/30) of the samples from the main source of drinking water plants and in 16.7% (5/30) from sewage. Viral concentrates obtained from three positive sewage samples were used to inoculate HepG2 cell cultures that were followed for one month; however, the viral genome was not detected in any cell culture. This study demonstrates the circulation of HEV in both source of drinking water plants and wastewater in Antioquia state, Colombia. The presence of HEV in environmental waters could be a risk for waterborne transmission in this population. The findings of the present study, together with the evidence of HEV circulation in human and swine in Colombia, should be consider by public health authorities for the development of surveillance programs and the inclusion of HEV infection diagnosis in the guidelines of viral hepatitis in the country. This is the first report of HEV in environmental samples in Colombia and the second one in Latin America.
Assuntos
Vírus da Hepatite E/isolamento & purificação , Hepatite E/epidemiologia , Hepatite E/virologia , Microbiologia da Água , Animais , Colômbia/epidemiologia , Monitoramento Ambiental , Genoma Viral , Geografia , Vírus da Hepatite E/genética , Humanos , Filogenia , RNA Viral , Esgotos/virologia , Carga ViralRESUMO
INTRODUCTION: Ten viral genotypes (A-J) distributed in all continents have been described for hepatitis B virus (HBV). One of the methodologies for determining the viral genotype is the restriction fragment length polymorphism (RFLP) technique, a simple and relatively inexpensive method, albeit with some limitations. OBJECTIVE: The initial objective of the project was to identify the HBV genotypes by RFLP in serum samples obtained from patients and blood donors. However, due to the discrepancies of RFLP patterns it was also necessary to perform phylogenetic genotyping and in silico analysis of HBV sequences. MATERIALS AND METHODS: We obtained 56 serum samples. DNA extraction was followed by PCR amplification of a fragment of HBV ORF S. We analyzed PCR products by RFLP with AlwI, BsrI, CfrI, HpaII and StyI, and we sequenced some. We compared the patterns obtained with those in previous reports. We also performed RFLP analysis in silico since we found differences between the patterns expected and those obtainedResults: We identified genotypes A and F, subgenotype F3, in the samples. This result is in agreement with those of previous studies carried out in Colombia; indeed, subgenotype F3 is the most frequent in the Andean region of the country, while genotype A is the most frequent HBV genotype in the western region (department of Chocó). Based on the in silico analysis of 229 HBV sequences from GenBank and 11 sequences of this study, we identified the RLFP pattern for genotype F, subgenotype F3, and we described some modifications of genotype A RFLP patterns. CONCLUSIONS: We identified the single nucleotide polymorphism pattern for genotype F, subgenotype F3, by in silico analysis and sequencing. Further robust in silico analyses are necessary to validate the RFLP patterns of HBV genotype and subgenotypes.
Assuntos
DNA Viral/sangue , Vírus da Hepatite B/genética , Vírus da Hepatite B/imunologia , Polimorfismo de Fragmento de Restrição/genética , Colômbia/epidemiologia , DNA Viral/química , Genótipo , Humanos , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição/fisiologia , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
Resumen Introducción: la exposición dietaria a la aflatoxina es un factor de riesgo para carcinoma hepatocelular, el cáncer primario de hígado más frecuente. Esta asociación se estableció gracias a la evidencia in vitro e in vivo de la relación entre la exposición a la aflatoxina B1 y la transversión G→T en el codón 249 del gen TP53, así como evidencia de la sinergia entre la aflatoxina y la infección crónica por virus de la hepatitis B. Métodos: se determinó la frecuencia de la mutación R249S del gen TP53 en 30 pacientes con diagnóstico de cirrosis y/o carcinoma hepatocelular quienes fueron sometidos a trasplante hepático en un hospital en Medellín, Colombia. Se extrajo ADN a partir de las muestras de explante hepático, se amplificó el fragmento de interés y se detectó la mutación por polimorfismos de longitud de fragmentos de restricción. Resultados: se encontró la mutación R249S en una de las 30 muestras analizadas (3,33 %) y se determinó, por medio de marcadores serológicos, infección por el virus de la hepatitis B en dos casos (6,67 %). No se encontró simultáneamente la mutación y la presencia de los marcadores de infección por virus de la hepatitis B. Conclusión: los resultados sugieren una baja exposición dietaria con aflatoxina B1 en la población de estudio. Sin embargo, es importante tener en cuenta la regulación de los límites permisibles de aflatoxina B1 y la inclusión en el diagnóstico diferencial de carcinoma hepatocelular, dada la heterogeneidad de las condiciones de la población en diferentes regiones del país.
Abstract Introduction: The dietary exposure to aflatoxin is a risk factor of hepatocellular carcinoma, the most frequent primary liver cancer. This risk factor was identified after in vivo and in vitro evidence of the relation between exposure to aflatoxin B1 and transversion G → T at 249 codon of the TP53 gene; as well as evidence of the synergy between hepatitis B virus chronic infection. Methods: the frequency of the R249S mutation of the TP53 gene was determined in 30 cases of cirrhosis and/or hepatocellular carcinoma, with liver transplantation in the hepatology unit of a hospital in Medellín, Colombia. DNA was extracted from the liver explant samples; the sequence of interest was amplified, and the mutation was detected by restriction fragment length polymorphisms. Results: the R249S mutation was found in 1 of the 30 samples analyzed (3.33 %); and hepatitis B virus infection was detected by serological markers in 2 of the 30 cases (6.67 %). We did not find the mutation and the presence of hepatitis B virus infection markers at the same time in any of the samples. Conclusion: The results suggest a low dietary exposure with aflatoxin B1 in the study population. However, it is important to take into consideration the regulation of the permissible limits of aflatoxin B1 and the inclusion in the differential diagnosis of hepatocellular carcinoma, given the heterogeneity of the conditions of the population in different regions of the country.
RESUMO
Resumen El virus de la hepatitis E es un patógeno hepatotrópico que se transmite por el agua y alimentos contaminados, y uno de los principales agentes etiológicos de hepatitis viral aguda de transmisión enteral en el mundo. La infección por el virus de la hepatitis E usualmente es autolimitada; sin embargo, se han descrito casos de infección crónica en pacientes inmunocomprometidos. La infección autolimitada no requiere tratamiento; por el contrario, la infección crónica debe tratarse debido al riesgo de progresión a cirrosis o a alguna de las manifestaciones extrahepáticas reportadas. En Colombia, la infección por el virus de la hepatitis E no hace parte del diagnóstico rutinario de hepatitis virales, a pesar de que existe evidencia de la circulación del virus en el país. El presente artículo de revisión tiene como objetivo describir las generalidades del virus de la hepatitis E, así como la historia natural de la infección y los estudios realizados en Colombia que evidencian su presencia en el país. La revisión se realizó mediante una búsqueda de literatura en la base de datos PubMed, SciELO y ScienceDirect, de trabajos originales y revisiones de tema publicados entre el período 1983-2017.
Abstract The hepatitis E virus, a hepatotropic pathogen transmitted by water and contaminated food, is one of the main etiological agents on the planet of enteral transmission of acute viral hepatitis. Hepatitis E infections are usually self-limiting, but cases of chronic infection have been described in immunocompromised patients. While self-limiting infections do not require treatment, chronic infections should be treated because of risk of progression to cirrhosis and/or extra-hepatic manifestations. In Colombia, hepatitis E infections are not included in the routine diagnosis of viral hepatitis, despite evidence of its presence in the country. The objective of this review is to provide a general description of the hepatitis E virus and the natural history of infections and to highlight studies carried out in Colombia showing its presence in the country. The review was carried out through a search in the PUBMED, SCIELO and ScienceDirect databases for of original papers and subject reviews published between 1983 and 2017.
Assuntos
Humanos , Hepatite E , Infecções , Epidemiologia , História NaturalRESUMO
Introducción. Uno de los principales factores de riesgo del carcinoma hepatocelular es el consumo crónico de alcohol. En estudios en diferentes poblaciones, se sugiere que las variantes genéticas de las enzimas que participan en el metabolismo del alcohol, como la alcohol deshidrogenasa (ADH) y la citocromo P450 (CYP2E1), estarían asociadas con riesgo de enfermedades hepáticas terminales. Objetivo. Identificar y caracterizar las variantes alélicas de los genes ADH1B, ADH1C y CYP2E1 en pacientes colombianos con diagnóstico de cirrosis y carcinoma hepatocelular. Materiales y métodos. Se incluyeron muestras de pacientes atendidos entre el 2005 y el 2007, y entre el 2014 y el 2016, en la unidad de hepatología de un hospital de Medellín. La genotipificación de las muestras se hizo mediante reacción en cadena de la polimerasa (Polymerase Chain Reaction, PCR) con análisis de los polimorfismos en la longitud de los fragmentos de restricción (Restriction Fragment Length Polymorphism, RFLP). Los resultados se compararon con los de dos grupos de control y con lo reportado en la base de datos del 1000 Genomes Project. Resultados. Se recolectaron 97 muestras de pacientes con diagnóstico de cirrosis y carcinoma hepatocelular. Los dos factores de riesgo más frecuentes fueron el consumo crónico de alcohol (18,6 %) y las colangiopatías (17,5 %). Los genotipos más frecuentes en la población de estudio fueron el ADH1B*1/1 (82 %), el ADH1C*1/1 (59 %) y el CYP2E1*C/C (84 %). Conclusiones. En este primer estudio de los polimorfismos en pacientes colombianos con diagnóstico de cirrosis y carcinoma hepatocelular, los genotipos más frecuentes fueron el ADH1B*1/1, el ADH1C*1/1 y el CYP2E1*C/C. No se observaron diferencias estadísticamente significativas en la frecuencia de los genotipos entre los casos y los controles. Se requieren estudios adicionales en población colombiana para evaluar el riesgo de la enfermedad hepática terminal por consumo crónico de alcohol y la asociación con los polimorfismos.
Introduction: One of the most important risk factors for hepatocellular carcinoma (HCC) is alcohol consumption: Studies in different populations suggest that the risk of liver disease could be associated with genetic variants of the enzymes involved in alcohol metabolism, such as alcohol dehydrogenase (ADH) and cytochrome P450 CYP2E1. Objective: To identify and characterize the allelic variants of ADH1B, ADH1C and CYP2E1 genes in Colombian patients with cirrhosis and/or HCC. Materials and methods: We included samples from patients attending the hepatology unit between 2005-2007 and 2014-2016 of a hospital in Medellin. Samples were genotyped using PCR-RFLP. We compared the results with two control groups and the 1000 Genomes Project database. Results: We collected 97 samples from patients with a diagnosis of cirrhosis and/or HCC. The two main risk factors were chronic alcohol consumption (18.6%) and cholangiopathies (17.5%). The most frequent genotypes in the study population were ADH1B*1/1 (82%), ADH1C*1/1 (59%), and CYP2E1*C/C (84%). Conclusions: This first study of polymorphisms in Colombian patients diagnosed with cirrhosis and/or HCC showed genotypes ADH1B*1/1, ADH1C*1/1 and CYP2E1*C/C as the most frequent. We found no significant differences in the genotype frequency between cases and controls. Further studies are necessary to explore the association between polymorphisms and the risk of end-stage liver disease from alcohol consumption.
Assuntos
Álcool Desidrogenase , Citocromo P-450 CYP2E1 , Carcinoma Hepatocelular/etiologia , Alelos , Genótipo , Cirrose Hepática/etiologiaRESUMO
Introduction: Ten viral genotypes (A-J) distributed in all continents have been described for hepatitis B virus (HBV). One of the methodologies for determining the viral genotype is the restriction fragment length polymorphism (RFLP) technique, a simple and relatively inexpensive method, albeit with some limitations. Objective: The initial objective of the project was to identify the HBV genotypes by RFLP in serum samples obtained from patients and blood donors. However, due to the discrepancies of RFLP patterns it was also necessary to perform phylogenetic genotyping and in silico analysis of HBV sequences. Materials and methods: We obtained 56 serum samples. DNA extraction was followed by PCR amplification of a fragment of HBV ORF S. We analyzed PCR products by RFLP with Alw I, Bsr I, Cfr I, Hpa II and Sty I, and we sequenced some. We compared the patterns obtained with those in previous reports. We also performed RFLP analysis in silico since we found differences between the patterns expected and those obtained. Results: We identified genotypes A and F, subgenotype F3, in the samples. This result is in agreement with those of previous studies carried out in Colombia; indeed, subgenotype F3 is the most frequent in the Andean region of the country, while genotype A is the most frequent HBV genotype in the western region (department of Chocó). Based on the in silico analysis of 229 HBV sequences from GenBank and 11 sequences of this study, we identified the RLFP pattern for genotype F, subgenotype F3, and we described some modifications of genotype A RFLP patterns. Conclusions: We identified the single nucleotide polymorphism pattern for genotype F, subgenotype F3, by in silico analysis and sequencing. Further robust in silico analyses are necessary to validate the RFLP patterns of HBV genotype and subgenotypes.
Introducción. Se han descrito diez genotipos (A-J) del virus de la hepatitis B (HBV) que están distribuidos en todos los continentes. Una de las técnicas utilizadas para determinar el genotipo viral es el análisis del polimorfismo de longitud de los fragmentos de restricción, un método simple y económico, pero con algunas limitaciones. Objetivo. El objetivo inicial del estudio fue identificar el genotipo del HBV mediante RFLP en muestras de suero obtenidas de pacientes y donantes de sangre. Sin embargo, por las discrepancias observadas en los patrones de RFLP fue necesario realizar análisis filogenéticos y un análisis in silico de secuencias del HBV. Materiales y métodos. Se obtuvieron 56 muestras de suero. Tras la extracción de ADN, se amplificó un fragmento del ORF S del HBV mediante reacción en cadena de la polimerasa, cuyos productos se analizaron por RFLP con las enzimas Alw I, Bsr I, Cfr I, Hpa II y Sty I, y algunos se secuenciaron. Los patrones obtenidos se compararon con los reportados previamente. Se efectuó un análisis in silico de RFLP en consideración de las diferencias entre los patrones esperados y los observados. Resultados. Se identificaron los genotipos A y F, subgenotipo F3, en las muestras. Este resultado coincide con lo descrito en estudios previos en los que se ha demostrado que el genotipo F, subgenotipo F3, es prevalente en la población de la región andina del país, en tanto que el genotipo A predomina en el occidente (departamento del Chocó). Con base en el análisis in silico de 229 secuencias virales obtenidas del GenBank y las 11 secuencias de este estudio, se caracterizó un nuevo patrón de RFLP específico para el genotipo F, subgenotipo F3, y se describieron algunas modificaciones en el patrón de RFLP del genotipo A, subgenotipo A1. Conclusiones. Se caracterizó el patrón de genotipificación del genotipo F, subgenotipo F3, del HBV mediante RFLP, análisis in silico y secuenciación. Se requieren nuevos análisis in silico con un número mayor de secuencias para validar los patrones de RFLP de los genotipos y subgenotipos del VHB.
Assuntos
Vírus da Hepatite B , Genótipo , Polimorfismo de Fragmento de RestriçãoRESUMO
Introducción: la infección oculta por el virus de la hepatitis B (VHB) se caracteriza por la presencia del genoma viral en suero y/o tejido hepático de individuos negativos para el antígeno de superficie HBsAg. La infección oculta se ha asociado con el desarrollo de cirrosis y carcinoma hepatocelular. Objetivo: identificar casos de infección oculta por el VHB en pacientes con diagnóstico de cirrosis y carcinoma hepatocelular, sometidos a trasplante hepático. Materiales y métodos: entre febrero de 2013 y marzo de 2014 fueron obtenidas muestras de explante hepático provenientes de pacientes con diagnóstico de cirrosis y/o carcinoma hepatocelular. Se detectó el genoma del VHB mediante amplificación de tres regiones del genoma viral (S, Core y X). Las muestras positivas se confirmaron por reacción en cadena de la polimerasa (PCR) en tiempo real para la región S. Resultados: se analizaron 15 muestras de tejido hepático, y en dos (13,3%) se detectó el genoma del VHB mediante PCR anidada para la región S y por PCR semianidada para la región X, resultado confirmado por PCR en tiempo real. Estas muestras provenían de pacientes negativos para los marcadores serológicos de infección por el VHB, anti-HBc y anti-HBs. Conclusión: la frecuencia de infección oculta reportada en este estudio es similar a lo reportado en Brasil en muestras de biopsias obtenidas de pacientes con hepatitis crónica. Estudios adicionales son necesarios para estimar la frecuencia de infección oculta por VHB (OBI) en pacientes con hepatopatías terminales en Colombia
Introduction: Occult hepatitis B virus infection is characterized by the presence of the viral genome in serum and/or liver tissue from individuals who test negative for the HBsAg surface antigen. Occult infection has been associated with the development of cirrhosis and hepatocellular carcinoma. Objective: The objective of this study was to identify cases of occult hepatitis B virus infection in patients with cirrhosis and/or hepatocellular carcinoma undergoing liver transplantation. Materials and methods: Between February 2013 and March 2014 hepatic explant samples were obtained from patients with cirrhosis and/or hepatocellular carcinoma. The hepatitis B virus genome was detected by amplification of three regions of the viral genome (S, Core and X). Positive samples were confirmed by real-time PCR for the S region. Results: Fifteen hepatic tissue samples were analyzed. The genome of the hepatitis B virus was detected in two (13.3%) samples by nested PCR for the S region and by semi-nested PCR for region X. The results were confirmed by real-time PCR. These samples came from patients who had tested negative for anti-HBc and anti-HBs serological markers for hepatitis B virus infection. Conclusion: The frequency of occult infection reported in this study is similar to that reported in Brazil in biopsy specimens obtained from patients with chronic hepatitis. Additional studies are needed to estimate the frequency of occult hepatitis B in patients with end-stage liver disease in Colombia
Assuntos
Humanos , Masculino , Feminino , Vírus da Hepatite B , Transplante de Fígado , Antígenos de Superfície da Hepatite B , Infecções , Diagnóstico , Hepatopatias , Antígenos de SuperfícieRESUMO
Introducción: el virus de la Hepatitis E (VHE), transmitido por la ruta fecal-oral, causa enfermedad hepática aguda. En Colombia se han realizado algunos estudios en pacientes con diagnóstico de hepatitis viral, en trabajadores de fincas porcícolas, en población porcina y en muestras ambientales. Objetivo: evaluar la presencia de anticuerpos anti-VHE en muestras de donantes de sangre del municipio de Yarumal, departamento de Antioquia. Metodología: se obtuvieron muestras de suero de donantes de sangre colectadas por la Cruz Roja Colombiana en una campaña de donación voluntaria en el municipio de Yarumal. En las muestras se determinó la presencia de anticuerpos anti-VHE tipo IgM e IgG mediante estuche comercial de ELISA. Resultados: se analizaron 42 muestras de suero, 19 de las cuales (45,2%) fueron positivas para anticuerpos anti-VHE IgG. Ninguna de las muestras fue positiva para anticuerpos anti-VHE tipo IgM. Conclusiones: este es el primer reporte de anticuerpos anti-VHE en donantes de sangre en Colombia. La frecuencia de anti-VHE (45,2%) es mayor a lo reportado previamente en otros estudios realizados en el país y a lo reportado en donantes de sangre en otros países de América Latina. Esta frecuencia podría estar relacionada con el contacto con cerdos infectados, así como con la exposición a agua contaminada con el virus. Sin embargo, estudios adicionales deben ser realizados en otras poblaciones similares en el país para confirmar este hallazgo.
Introduction: The hepatitis E virus (HEV) is transmitted via the fecal-oral route and causes acute liver disease. In Colombia there have been some studies of patients who have been diagnosed with viral hepatitis, of swine farm workers and in environmental samples. Objective: The objective of this study was evaluate samples from blood donors in the municipality of Yarumal in the department of Antioquia for the presence of anti-HEV antibodies. Methods: Serum samples were obtained from blood donated to the Colombian Red Cross by blood donors on a voluntary basis in a campaign in the municipality of Yarumal. Samples in the presence of anti-HEV IgM and IgG ELISA using commercial kit was determined.Results: Forty-two serum samples were analyzed: 19 (45.2%) were positive for anti-HEV IgG. None of the samples were positive for anti-HEV IgM. Conclusions: This is the first report of anti-HEV antibodies in blood donors in Colombia. The frequency of anti-HEV (45.2%) is higher than previously reported in other studies in this country and in blood donors in other Latin American countries. This frequency may be linked to contact with infected pigs and to exposure to water contaminated with the virus. However, additional studies should be conducted in similar populations in the country to confirm this finding
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Anticorpos , Doadores de Sangue , Ensaio de Imunoadsorção Enzimática , Vírus da Hepatite E , População RuralRESUMO
La alteración de las vías de señalización es un mecanismo común en la oncogénesis de diferentes tipos de tumor. La modificación de una de las proteínas de la vía por mutaciones o por modificaciones genéticas o epigenéticas en el promotor del gen correspondiente podría generar una alteración en la vía, y por tanto condiciones para el crecimiento descontrolado característico del cáncer. La vía de señalización Wnt/β-catenina, donde β-catenina actúa como coactivador, es muy importante en procesos de embriogénesis, organogénesis y homeostasis. La alteración de Wnt/β-catenina por mutaciones o modificaciones epigenéticas de β-catenina o de otras proteínas facilita la acumulación de β-catenina en el núcleo y genera una activación permanente de esta vía de señalización. Este evento desencadena la expresión de genes que codifican proteínas que participan en proliferación celular, diferenciación y mantenimiento de células madre. β-catenina participa también en la adhesión célulacélula, mediando la interacción entre cadherinas y actina. Alteraciones en el complejo β-catenina-cadherina-actina lleva a la pérdida de la adhesión y a una alta capacidad invasiva de las células afectadas, mecanismos asociados con la capacidad de metástasis de las células tumorales. En esta revisión se describe la proteína β-catenina y su papel en la vía Wnt/ β-catenina, así como en la regulación de la expresión génica y en el proceso de adhesión célula-célula, y las alteraciones que pueden desencadenar un proceso oncogénico.
The modification of signaling pathways is a common mechanism in the oncogénesis process of different types of tumor. An alteration in any protein of the pathway by genetic mutations or by epigenetic changes in its gene promoter could cause misregulation of the pathway and therefore lead to uncontrolled cell proliferation. The Wnt/β-catenin signaling pathway is important in several processes, such as embryogenesis, organogenesis and homeostasis. β-catenin protein acts as a co-activator of this pathway, and when it is translocated to the nucleus, it functions as a transcription factor. An imbalance in this pathway by mutations or epigenetic modifications of β-catenin and/or other proteins, favors the accumulation of β-catenin in the nucleus, leading to permanent activation of Wnt/β-catenin signaling pathway. This event triggers the expression of genes encoding proteins involved in cell proliferation, differentiation and maintenance of stem cells. β-catenin is also known to participate in cell-cell adhesion, mediating the interaction between Cadherin and Actin. Alterations in the complex β-catenin-Cadherin-Actin lead to a loss of adhesion and a high invasive capacity of affected cells, mechanisms associated with invasiveness of tumor cells. This review describes the β-catenin protein, and its role in the Wnt/β-catenin signaling pathway, as well as in gene expression regulation and cellcell adhesion, and the alterations that can trigger an oncogenic process.