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Search Results: 1 - 10 of 1334 matches for " Agustin Benito "
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Trypanosoma brucei gambiense Adaptation to Different Mammalian Sera Is Associated with VSG Expression Site Plasticity
Carlos Cordon-Obras, Jorge Cano, Dolores González-Pacanowska, Agustin Benito, Miguel Navarro, Jean-Mathieu Bart
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0085072
Abstract: Trypanosoma brucei gambiense infection is widely considered an anthroponosis, although it has also been found in wild and domestic animals. Thus, fauna could act as reservoir, constraining the elimination of the parasite in hypo-endemic foci. To better understand the possible maintenance of T. b. gambiense in local fauna and investigate the molecular mechanisms underlying adaptation, we generated adapted cells lines (ACLs) by in vitro culture of the parasites in different mammalian sera. Using specific antibodies against the Variant Surface Glycoproteins (VSGs) we found that serum ACLs exhibited different VSG variants when maintained in pig, goat or human sera. Although newly detected VSGs were independent of the sera used, the consistent appearance of different VSGs suggested remodelling of the co-transcribed genes at the telomeric Expression Site (VSG-ES). Thus, Expression Site Associated Genes (ESAGs) sequences were analysed to investigate possible polymorphism selection. ESAGs 6 and 7 genotypes, encoding the transferrin receptor (TfR), expressed in different ACLs were characterised. In addition, we quantified the ESAG6/7 mRNA levels and analysed transferrin (Tf) uptake. Interestingly, the best growth occurred in pig and human serum ACLs, which consistently exhibited a predominant ESAG7 genotype and higher Tf uptake than those obtained in calf and goat sera. We also detected an apparent selection of specific ESAG3 genotypes in the pig and human serum ACLs, suggesting that other ESAGs could be involved in the host adaptation processes. Altogether, these results suggest a model whereby VSG-ES remodelling allows the parasite to express a specific set of ESAGs to provide selective advantages in different hosts. Finally, pig serum ACLs display phenotypic adaptation parameters closely related to human serum ACLs but distinct to parasites grown in calf and goat sera. These results suggest a better suitability of swine to maintain T. b. gambiense infection supporting previous epidemiological results.
Accuracy of an Immunochromatographic Diagnostic Test (ICT Malaria Combo Cassette Test) Compared to Microscopy among under Five-Year-Old Children when Diagnosing Malaria in Equatorial Guinea
José-Luis Portero,Maria Rubio-Yuste,Miguel Angel Descalzo,Jose Raso,Magdalena Lwanga,Jaquelina Obono,Gloria Nseng,Agustin Benito,Jorge Cano
Malaria Research and Treatment , 2010, DOI: 10.4061/2010/858427
Abstract: Conventional malaria diagnosis based on microscopy raises serious difficulties in weak health systems. Cost-effective and sensitive rapid diagnostic tests have been recently proposed as alternatives to microscopy. In Equatorial Guinea, a study was conducted to assess the reliability of a rapid diagnostic test compared to microscopy. The study was designed in accordance with the directives of the Standards for Reporting Diagnostic Accuracy Initiative (STARD). Peripheral thick and thin films for the microscopy diagnosis and a rapid immunochromatographic test (ICT Malaria Combo Cassette Test) were performed on under five-year-old children with malaria suspicion. The ICT test detected Plasmodium spp. infection with a sensitivity of 81.5% and a specificity of 81.9% while P. falciparum diagnosis occurred with a sensitivity of 69.7% and a specificity of 73.7%. The sensitivity of the ICT test increased with higher parasitemias. The general results showed little concordance between the ICT test and microscopy (kappa = 0.28, se: 0.04). In Equatorial Guinea, the ICT Malaria Combo Cassette Test has proven to be an acceptable test to detect high P. falciparum parasitemias. However, the decrease of sensitivity at medium and low parasitemias hampers that ICT can replace properly performed microscopy at present in the diagnosis of malaria in children. 1. Background The current malaria control strategies are mainly based on early diagnosis and a correct treatment of the cases. These are essential to reduce the fatal outcome of the disease [1]. However, the weakness of the health systems in many endemic countries, particularly at the peripheral level, means that the malaria diagnosis has to be based on clinical criteria. Taking into account that other infectious diseases course with signs and symptoms like malaria, a high percentage of overdiagnosis can be expected in a tropical area [2–4]. The growing resistance to drugs commonly used for malaria treatment (chloroquine, quinine, and sulphadoxine-pyrimethamine), due to their abusive use in the past, and the arrival of artemisinin-based combination therapies (ACTs), which are more expensive than the former, mean that the methods to diagnose malaria are once again back in the spotlight. Microscopy and the use of rapid diagnostic tests (RDTs) are currently considered to be the two diagnostic procedures with the greatest impact on controlling malaria [5]. Microscopy can be a highly useful diagnostic tool, as in expert hands it can detect up to 50 parasites per l (0.001% parasitemia) and identify the plasmodia in 98% of the
Duffy Negative Antigen Is No Longer a Barrier to Plasmodium vivax – Molecular Evidences from the African West Coast (Angola and Equatorial Guinea)
Cristina Mendes,Fernanda Dias,Joana Figueiredo,Vicenta Gonzalez Mora,Jorge Cano,Bruno de Sousa,Virgílio E. do Rosário,Agustin Benito,Pedro Berzosa,Ana Paula Arez
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001192
Abstract: Background Plasmodium vivax shows a small prevalence in West and Central Africa due to the high prevalence of Duffy negative people. However, Duffy negative individuals infected with P. vivax have been reported in areas of high prevalence of Duffy positive people who may serve as supply of P. vivax strains able to invade Duffy negative erythrocytes. We investigated the presence of P. vivax in two West African countries, using blood samples and mosquitoes collected during two on-going studies. Methodology/Findings Blood samples from a total of 995 individuals were collected in seven villages in Angola and Equatorial Guinea, and 820 Anopheles mosquitoes were collected in Equatorial Guinea. Identification of the Plasmodium species was achieved by nested PCR amplification of the small-subunit rRNA genes; P. vivax was further characterized by csp gene analysis. Positive P. vivax-human isolates were genotyped for the Duffy blood group through the analysis of the DARC gene. Fifteen Duffy-negative individuals, 8 from Equatorial Guinea (out of 97) and 7 from Angola (out of 898), were infected with two different strains of P. vivax (VK210 and VK247). Conclusions In this study we demonstrated that P. vivax infections were found both in humans and mosquitoes, which means that active transmission is occurring. Given the high prevalence of infection in mosquitoes, we may speculate that this hypnozoite-forming species at liver may not be detected by the peripheral blood samples analysis. Also, this is the first report of Duffy negative individuals infected with two different strains of P. vivax (VK247 and classic strains) in Angola and Equatorial Guinea. This finding reinforces the idea that this parasite is able to use receptors other than Duffy to invade erythrocytes, which may have an enormous impact in P. vivax current distribution.
Microscopy and molecular biology for the diagnosis and evaluation of malaria in a hospital in a rural area of Ethiopia
Maria A Santana-Morales, Raquel N Afonso-Lehmann, Maria A Quispe, Francisco Reyes, Pedro Berzosa, Agustin Benito, Basilio Valladares, Enrique Martinez-Carretero
Malaria Journal , 2012, DOI: 10.1186/1475-2875-11-199
Abstract: A cross-sectional survey of 471 individuals was carried out in a hospital in the rural area of Gambo (Ethiopia). Blood samples were prepared for microscopic observation and collected in filter paper for Seminested-Multiplex PCR (SnM-PCR) and real time PCR (qPCR) testing. The SnM-PCR was considered as the gold standard technique and compared with the rest. Thus, agreement between SnM-PCR and LM was determined by calculating Kappa Statistics and correlation between LM and qPCR quantification was calculated by pair-wise correlation co-efficient.Samples analysed by LM and SnM-PCR were positive for Plasmodium sp. 5.5% and 10.5%, respectively. Sensitivity was 52.2% by LM and 70% by qPCR. Correlation co-efficient between microscopy counts and qPCR densities for Plasmodium vivax was R2?=?0.586. Prevalence was estimated at 7% (95% CI: 4.7–9.3). Plasmodium vivax was the dominant species detected and the difference was statistically significant (χ2?=?5.121 p?<?0.05). The highest prevalence of the parasite (10.9%) was observed in age groups under 15?years old.Accurate malaria diagnostic methods have a great effect in the reduction of the number of malaria-infected individuals. SnM-PCR detection of malaria parasites may be a very useful complement to microscopic examination in order to obtain the real prevalence of each Plasmodium species. Although SnM-PCR shows that it is a good tool for the determination of Plasmodium species, today light microscopy remains the only viabletool for malaria diagnosis in developing countries. Therefore, re-inforcement in the training of microscopists is essential for making the correct diagnosis of malaria. Plasmodium vivax was the predominant species in Gambo, a meso-endemic area for this species.
Transmission of malaria and genotypic variability of Plasmodium falciparum on the Island of Annobon (Equatorial Guinea)
Jorge Cano, Pedro Berzosa, Aida de Lucio, Miguel Descalzo, Leonardo Bobuakasi, Sisinio Nzambo, Melchor Ondo, Jesus N Buatiche, Gloria Nseng, Agustin Benito
Malaria Journal , 2007, DOI: 10.1186/1475-2875-6-141
Abstract: A blood sample was taken from the selected children in order to determine Plasmodium infection by microscopical examination and by semi-nested multiplex PCR. The diversity of P. falciparum circulating alleles was studied on the basis of the genes encoding for the merozoite surface proteins, MSP-1 and MSP-2 of P. falciparum.The crude parasite rate was 17% during the dry season and 60% during the rainy season. The percentage of children sleeping under a bed net was over 80% in the two surveys. During the rainy season, 33.3% of the children surveyed were anaemic at the time of the study. No association was found between the crude parasite rate, the use of bed nets and gender, and anaemia. However, children between five and nine years of age were five times less at risk of being anaemic than those aged less than one year. A total of 28 populations of the three allelic families of the msp-1 gene were identified and 39 of the msp-2 gene. The variability of circulating allelic populations is significantly higher in the rainy than in the dry season, although the multiplicity of infections is similar in both, 2.2 and 1.9 respectively.Based on the high degree of geographical isolation of the Annobon population and the apparent marked seasonality of the transmission, it is feasible to believe that malaria can be well controlled from this small African island.Plasmodium falciparum is a highly polymorphic parasite with a high antigens heterogeneity [1]. This heterogeneity may represent a major obstacle to the development of an effective vaccine [2].In general, the P. falciparum infections include a complex mixture of biologically and genetically different populations, as has been demonstrated by different techniques, including the Restriction Fragment Length Polymorphism (RFLP) [3] and the Polymerase Chain Reaction (PCR) [4]. PCR has been used to study the existing polymorphisms in various markers, such as the Merozoite Surface Proteins 1 (MSP-1) and 2 (MSP-2), the circumsporozo
Contribución al estudio de las secuelas de la parálisis infantil en el Hospital Arriarán
AGUSTIN INOSTROSA
Revista chilena de pediatría , 1942,
Abstract:
Iron Overload and HFE Mutations: Are They Relevant in Cryptogenic Cirrhosis?
Agustin Castiella
Hepatitis Monthly , 2012,
Abstract:
Hepatitis B Virus Genotype G Infection in a Turkish Patient Undergoing Hemodialysis Therapy
Agustin Castiella
Hepatitis Monthly , 2012,
Abstract: Background: Genotype G is the least common of all the hepatitis B virus (HBV) genotypes. The existence of the genotype G strain of HBV was first noted in 2000 and little information is available on its global geographical distribution. Previous studies have demonstrated the dominance of genotype D in patients with HBV infections in Turkey.Objectives: To report for the first time in Turkey, the case of a 61 year old male patient who developed the HBV genotype G infection.Case report: According to HBV genotyping using phylogenetic analysis and an INNO-LiPA assay, the patient was infected with genotype G and G+A, respectively.Conclusions: The present clinical study suggests that the transmission of an HBV genotype other than genotype D, namely HBV genotype G, is possible in Turkey. Epidemiological and clinical information on genotype G infection is currently limited, and this is most likely due to its low prevalence throughout the world. Therefore, it may be important to determine the epidemiologic and molecular characteristics of the HBV genotype G as it relates to chronic hepatitis, to enable better understanding of its circulation and progression around the world.
El problema de la forma de gobierno en la doctrina política de Spinoza. Una lectura de la democracia como enmendación de los afestos y las instituciones El problema de la forma de gobierno en la doctrina política de Spinoza. Una lectura de la democracia como enmendación de los afestos y las instituciones
Agustin Volco
Scienza & Politica : per una Storia delle Dottrine , 2011, DOI: 10.6092/issn.1825-9618/2730
Abstract: El problema de la forma de gobierno en la doctrina política de Spinoza. Una lectura de la democracia como enmendación de los afestos y las instituciones
Una exposicion del Derecho
Agustin Squella
Sequência : Estudos Juridicos e Politicos , 1984,
Abstract:
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