Plasmodium vivax lineages: geographical distribution, tandem repeat polymorphism, and phylogenetic relationship

Background: Multi-drug resistance and severe/ complicated cases are the emerging phenotypes of vivax malaria, which may deteriorate current anti-malarial control measures. The emergence of these phenotypes could be associated with either of the two Plasmodium vivax lineages. The two lineages had been categorized as Old World and New World, based on geographical sub-division and genetic and phenotypical markers. This study revisited the lineage hypothesis of P. vivax by typing the distribution of lineages among global isolates and evaluated their genetic relatedness using a panel of new mini-satellite markers. Methods: 18S SSU rRNA S-type gene was amplified from 420 Plasmodium vivax field isolates collected from different geographical regions of India, Thailand and Colombia as well as four strains each of P. vivax originating from Nicaragua, Panama, Thailand (Pak Chang), and Vietnam (ONG). A mini-satellite marker panel was then developed to understand the population genetic parameters and tested on a sample subset of both lineages. Results: 18S SSU rRNA S-type gene typing revealed the distribution of both lineages (Old World and New World) in all geographical regions. However, distribution of Plasmodium vivax lineages was highly variable in every geographical region. The lack of geographical sub-division between lineages suggests that both lineages are globally distributed. Ten mini-satellites were scanned from the P. vivax genome sequence; these tandem repeats were located in eight of the chromosomes. Mini-satellites revealed substantial allelic diversity (7-21, AE = 14.6 +/- 2.0) and heterozygosity (He = 0.697-0.924, AE = 0.857 +/- 0.033) per locus. Mini-satellite comparison between the two lineages revealed high but similar pattern of genetic diversity, allele frequency, and high degree of allele sharing. A Neighbour-Joining phylogenetic tree derived from genetic distance data obtained from ten mini-satellites also placed both lineages together in every cluster. Conclusions: The global lineage distribution, lack of genetic distance, similar pattern of genetic diversity, and allele sharing strongly suggested that both lineages are a single species and thus new emerging phenotypes associated with vivax malaria could not be clearly classified as belonging to a particular lineage on basis of their geographical origin.

Análisis de las etapas del proceso de mediación familiar desde el Modelo Relacional Simbólico, en una intervención a una pareja en situación de separación de la Localidad de Puente Aranda. Bogotá D.C. 2008

La presente investigación se realizó con el objetivo de describir y analizar una mediación familiar hecha con la metodología del modelo relacional simbólico, por dos alumnos de la maestría en mediación familiar y comunitaria, a una pareja en situación de separación. Para ello se construyó un protocolo de acuerdo al modelo relacional simbólico, para la selección de las parejas. Por medio de la metodología determinada por la investigación cualitativa y específicamente el estudio de caso, los investigadores hicieron la recolección de la información, teniendo como guía los conceptos que se trabajaron en la mediación familiar, que corresponden a, los géneros, el relanzamiento de los vínculos, las generaciones y las estirpes. Una vez seleccionada la pareja se realizó la mediación familiar de acuerdo a las etapas y metodología planteada por el modelo, haciendo un registro pormenorizado de cada sesión. Finalizada la mediación familiar los investigadores realizaron la descripción y el análisis de lo ocurrido, encontrando como las varias sesiones y los objetivos de las mismas benefician a los padres en el transito de su separación, potenciando su rol como padres y relanzando los vínculos que los unen. El cumplimiento de las etapas fue adecuado, sin embargo en el manejo de la técnica los mediadores familiares tuvieron imprecisiones que los alejaron en algunos momentos del modelo relacional simbólico, debido a la falta de experticia frente a la aplicación de la mediación familiar. Los investigadores presentan recomendaciones para la formación y el entrenamiento de mediadores familiares de acuerdo al modelo relacional simbólico.

Análisis de la concentración del poder político enColombia, a través de los linajes presidenciales del siglo XX. Estudio de caso: familia Ospina, López, Lleras y Pastrana.

La conformación de la la élite del poder político en Colombia está centrada en la formación y estructuración de la misma, basada en la herencia hispánica, arraigada desde la Colonia, y cuyas divergencias y convergencias de los linajes presidenciales tienen como cenit el siglo XX.

"Identification and Diversity of Killer Cell Ig-Like Receptors in Aotus vociferans, a New World Monkey "

Previous BAC clone analysis of the Platyrrhini owl monkey KIRs have shown an unusual genetic structure in some loci. Therefore, cDNAs encoding KIR molecules from eleven Aotus vociferans monkeys were characterized here; tenputative KIR loci were found, some of which encoded atypical proteins such as KIR4DL and transcripts predicted to encode a D0+D1 configuration (AOTVOKIR2DL1*01v1) which appear to be unique in the Aotus genus. Furthermore, alternative splicing was found as a likely mechanism for producing activator receptors in A. vociferans species. KIR proteins from New World monkeys may be split into three new lineages according to domain by domain phylogenetic analysis. Although the A. vociferans KIR family displayed a high divergence among paralogous genes, individual loci were limited in their genetic polymorphism. Selection analysis showed that both constrained and rapid evolution may operate within the AvKIR family. The frequent alternative splicing (as a likely mechanism generating activator receptors), the presence of KIR4DL and KIR2DL1 (D0+D1) molecules and other data reported here suggest that the KIR family in Aotus has had a rapid evolution, independent from its Catarrhini counterparts.from its Catarrhini counterparts.

Hematopoietic stem cells, overview and pathways implied on their self-renewal mechanisms

Blood tissue is composed approximately in 45% by cells and its derivatives, with a life span of around 120 days for erythrocytes and 3 years for certain type of lymphocytes. This lost is compensated with the hematopoietic system activity and the presence of an immature primitive cell population known as Hematopoietic Stem Cells (HSCs) which perform the hematopoiesis, a process that is active from the beginning of the fetal life and produces near to 2 x 1011 eritrocytes and 1010 white blood cells per day (1). Hematopoietic Stem Cells are capable of both self-renewal and differentiation into multiple lineages, are located in a particular niche and are identified by their own cell surface markers, as the CD34 antigen. Recently it has been possible to advance in the understanding of self-renewal, differentiation and proliferation processes and in the involvement of the signaling pathways Hedgehog, Notch and Wnt. Studying the influence of these mechanisms on in vivo and in vitro behavior and the basic biology of HSCs, has given valuable tools for the generation of alternative therapies for hematologic disorders as leukemias.