Perspectivas epistemológicas no estudo científico e a avaliação clínica das funções executivas

En este artículo se examinan perspectivas epistemológicas que han moldeado e influenciado la búsqueda científica orientada hacia comprender aquello que los neuropsicólogos denominan las "funciones ejecutivas (FE). El término funciones ejecutivas se refiere a aspectos de control de la cognición y la conducta. Las ideas expuestas en este manuscrito presuponen que la orientación epistemológica de una persona determina la manera en la que ella conceptualiza la interacción entre las funciones cerebrales y su entorno físico. Cada una de esas orientaciones conlleva suposiciones acerca del modo como operan las FE y, por ende, el modo como deben ser evaluadas. Hasta fechas recientes esto se había abordado principalmente desde el punto de vista de dos perspectivas teóricas. Una de ellas, la analítica, tiene sus raíces en el movimiento positivista. La otra, también conocida como "ciencia romántica" es sintética, y provee las bases del trabajo científico del muy celebrado neuropsicólogo ruso A.R. Luria. Una tercera perspectiva, formulada en el marco de la "cognición corpórea", ha sido propuesta en los últimos 20 años, y está más estrechamente asociada con los trabajos de Francisco Varela. Se examina aquí, por medio de una revisión reflexiva e integradora de la literatura pertinente, la manera como esas tres perspectivas epistemológicas han influido sobre la investigación y la práctica clínica de la neuropsicología.In this article, epistemological perspectives that have shaped and affected the scientific quest for understanding what neuropsychologists term "executive functions" are reviewed. Executive functions refer to the control functions of cognition and behavior. The underlying thesis of the paper is that one's epistemological orientation determines how one sees the interaction between brain functions and our status in the world. Each different orientation thus carries with it implications with regard to how executive functions operate, as well as how, therefore, one should try to assess them. Until recently, these functions were approached through two primary epistemological points of view. One is analytic, which has its roots in the positivistic movement. The other approach is synthetic, otherwise known as "romantic science", and forms the basis of the work of the prominent Russian neuropsychologist A.R. Luria. A third epistemological perspective, articulated under the umbrella of 'embodied cognition' approaches, has been advanced in the last 20 years, and is associated most closely with the work of Francisco Varela. A review of, and reflection on how these perspectives have affected research and clinical practice in neuropsychology is provided.Neste artigo examinam-se as perspectivas epistemológicas que moldaram e influenciaram a busca científica orientada à compreender aquilo que os neuropsicólogos denominam as "funções executivas (FE). O termo funções executivas se refere a aspectos de controle da cognição e a conduta. As ideias expostas neste manuscrito pressupõem que a orientação epistemológica de uma pessoa determina a maneira em que ela conceitualiza a interação entre as funções cerebrais e seu entorno físico. Cada uma dessas orientações leva a suposições sobre o modo como operam as FE e, portanto, o modo como devem ser avaliadas. Até datas recentes isto havia sido abordado principalmente desde o ponto de vista de duas perspectivas teóricas. Uma delas, a analítica, tem suas raízes no movimento positivista. A outra, também conhecida como "ciência romântica" é sintética, e fornece as bases do trabalho científico do muito celebrado neuropsicólogo russo A.R. Luria. Uma terceira perspectiva, formulada no marco da "cognição corpórea", foi proposta nos últimos 20 anos, e está mais estreitamente associada com os trabalhos de Francisco Varela. Examina-se aqui, através de uma revisão reflexiva e integradora da literatura pertinente, a maneira como essas três perspectivas epistemológicas influíram sobre a pesquisa e a prática da neuropsicologia

Morphological and Transcriptional Changes in Human Bone Marrow During Natural Plasmodium vivax Malaria Infections.

--- - Label: BACKGROUND NlmCategory: BACKGROUND content: The presence of Plasmodium vivax malaria parasites in the human bone marrow (BM) is still controversial. However, recent data from a clinical case and experimental infections in splenectomized nonhuman primates unequivocally demonstrated the presence of parasites in this tissue. - Label: METHODS NlmCategory: METHODS content: In the current study, we analyzed BM aspirates of 7 patients during the acute attack and 42 days after drug treatment. RNA extracted from CD71+ cell suspensions was used for sequencing and transcriptomic analysis. - Label: RESULTS NlmCategory: RESULTS content: We demonstrated the presence of parasites in all patients during acute infections. To provide further insights, we purified CD71+ BM cells and demonstrated dyserythropoiesis and inefficient erythropoiesis in all patients. In addition, RNA sequencing from 3 patients showed that genes related to erythroid maturation were down-regulated during acute infections, whereas immune response genes were up-regulated. - Label: CONCLUSIONS NlmCategory: CONCLUSIONS content: This study thus shows that during P. vivax infections, parasites are always present in the BM and that such infections induced dyserythropoiesis and ineffective erythropoiesis. Moreover, infections induce transcriptional changes associated with such altered erythropoietic response, thus highlighting the importance of this hidden niche during natural infections

Plasmodium vivax gametocytes in the bone marrow of an acute malaria patient and changes in the erythroid miRNA profile

Plasmodium vivax is the most widely distributed human malaria parasite and responsible for large amounts of disease and burden [1]. The presence of P. vivax in the bone marrow was first noticed in the late 19th century [2], and examinations of sternal bone marrow aspirates were performed as an accessory to examinations of peripheral blood in malaria, including P. vivax [3]. Since then, little progress has been made in studying P. vivax infections in this tissue. One report explored accumulation of dyserythropoietic cells in anaemic infected patients [4]. In addition, two case studies reported P. vivax infections after autologous bone marrow transplantation [5][6], and a third one documented an accidental P. vivax infection due to bone marrow transplantation between a malaria-infected donor and a malaria-free receptor [7]. In Brazil, one patient with persistent thrombocytopaenia and an enlarged spleen was diagnosed with chronic P. vivax malaria after the finding of schizonts in the bone marrow aspirate [8]. In all these reports and case studies, however, parasite loads and life stages found in the bone marrow were not investigated, and no molecular tools were available to rule out mixed infections or to characterize specific parasite stages

Pparγ2 Is a Key Driver of Longevity in the Mouse

Aging involves a progressive physiological remodeling that is controlled by both genetic and environmental factors. Many of these factors impact also on white adipose tissue (WAT), which has been shown to be a determinant of lifespan. Interrogating a transcriptional network for predicted causal regulatory interactions in a collection of mouse WAT from F2 crosses with a seed set of 60 known longevity genes, we identified a novel transcriptional subnetwork of 742 genes which represent thus-far-unknown longevity genes. Within this subnetwork, one gene was Pparg (Nr1c3), an adipose-enriched nuclear receptor previously not associated with longevity. In silico, both the PPAR signaling pathway and the transcriptional signature of Pparγ agonist rosiglitazone overlapped with the longevity subnetwork, while in vivo, lowered expression of Pparg reduced lifespan in both the lipodystrophic Pparg1/2-hypomorphic and the Pparg2-deficient mice. These results establish Pparγ2 as one of the determinants of longevity and suggest that lifespan may be rather determined by a purposeful genetic program than a random process

Nuclear Translocation of β-Catenin during Mesenchymal Stem Cells Differentiation into Hepatocytes Is Associated with a Tumoral Phenotype

Wnt/β-catenin pathway controls biochemical processes related to cell differentiation. In committed cells the alteration of this pathway has been associated with tumors as hepatocellular carcinoma or hepatoblastoma. The present study evaluated the role of Wnt/β-catenin activation during human mesenchymal stem cells differentiation into hepatocytes. The differentiation to hepatocytes was achieved by the addition of two different conditioned media. In one of them, β-catenin nuclear translocation, up-regulation of genes related to the Wnt/β-catenin pathway, such as Lrp5 and Fzd3, as well as the oncogenes c-myc and p53 were observed. While in the other protocol there was a Wnt/β-catenin inactivation. Hepatocytes with nuclear translocation of β-catenin also had abnormal cellular proliferation, and expressed membrane proteins involved in hepatocellular carcinoma, metastatic behavior and cancer stem cells. Further, these cells had also increased auto-renewal capability as shown in spheroids formation assay. Comparison of both differentiation protocols by 2D-DIGE proteomic analysis revealed differential expression of 11 proteins with altered expression in hepatocellular carcinoma. Cathepsin B and D, adenine phosphoribosyltransferase, triosephosphate isomerase, inorganic pyrophosphatase, peptidyl-prolyl cis-trans isomerase A or lactate dehydrogenase β-chain were up-regulated only with the protocol associated with Wnt signaling activation while other proteins involved in tumor suppression, such as transgelin or tropomyosin β-chain were down-regulated in this protocol. In conclusion, our results suggest that activation of the Wnt/β-catenin pathway during human mesenchymal stem cells differentiation into hepatocytes is associated with a tumoral phenotype

Network Economics and the Environment: Insights and Perspectives

Local interactions and network structures appear to be a prominent feature of many environmental problems. This paper discusses a wide range of issues and potential areas of application, including the role of relational networks in the pattern of adoption of green technologies, common pool resource problems characterized by a multiplicity of sources, the role of social networks in multi-level environmental governance, infrastructural networks in the access to and use of natural resources such as oil and natural gas, the use of networks to describe the internal structure of inter-country relations in international agreements, and the formation of bilateral "links" in the process of building up an environmental coalition. For each of these areas, we examine why and how network economics would be an effective conceptual and analytical tool, and discuss the main insights that we can foresee

Hydrology Affects Environmental and Spatial Structuring of Microalgal Metacommunities in Tropical Pacific Coast Wetlands

The alternating climate between wet and dry periods has important effects on the hydrology and therefore on niche-based processes of water bodies in tropical areas. Additionally, assemblages of microorganism can show spatial patterns, in the form of a distance decay relationship due to their size or life form. We aimed to test spatial and environmental effects, modulated by a seasonal flooding climatic pattern, on the distribution of microalgae in 30 wetlands of a tropical dry forest region: the Pacific coast of Costa Rica and Nicaragua. Three surveys were conducted corresponding to the beginning, the highest peak, and the end of the hydrological year during the wet season, and species abundance and composition of planktonic and benthic microalgae was determined. Variation partitioning analysis (as explained by spatial distance or environmental factors) was applied to each seasonal dataset by means of partial redundancy analysis. Our results show that microalgal assemblages were structured by spatial and environmental factors depending on the hydrological period of the year. At the onset of hydroperiod and during flooding, neutral effects dominated community dynamics, but niche-based local effects resulted in more structured algal communities at the final periods of desiccating water bodies. Results suggest that climatemediated effects on hydrology can influence the relative role of spatial and environmental factors on metacommunities of microalgae. Such variability needs to be accounted in order to describe accurately community dynamics in tropical coastal wetlands.Agencia Española de Cooperación y Desarrollo/[A1024073/09]/AECID/EspañaAgencia Española de Cooperación y Desarrollo/[A/031019/10]/AECID/EspañaAgencia Española de Cooperación y Desarrollo/[C/032994/10]/AECID/EspañaAgencia Española de Cooperación y Desarrollo/[A3/ 036594/11]/AECID/EspañaUniversidad de Costa Rica/[741-B1-517]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)UCR::Vicerrectoría de Docencia::Salud::Facultad de Microbiologí

Effect of co-morbid depression on Continuous Performance Test (CPT) tasks in college students with Attention Deficit Hyperactivity Disorder (ADHD)

Se le ha dado poco énfasis al impacto de la coexistencia de la depresión y el trastorno de déficit de atención con hiperactividad, TDA-H en los procesos atencionales a pesar de la alta tasa de coexistencia. Ambas condiciones afectan las áreas corticales prefrontales, y en ambas se presentan quejas de falta de atención en los afectados. En este estudio se compara la ejecución de estudiantes universitarios con TDA-H, con o sin depresión, en tareas computarizadas de atención sostenida. Los participantes fueron agrupados según su edad, nivel educativo, género, CI, y abuso de alcohol y drogas. Los resultados indican que las dos condiciones conjuntas haben que se incremente el número de errores y de omisiones tanto en la condición anticipatoria como en la no anticipatoria. Estos resultados guardan relación con teorías actuales sobre las funciones de los neurotransmisores catecolaminérgicos, y en particular del papel de la dopamina y la epinefrina en los estados de alerta tónicos y fásicos

Differential Performance of Post-traumatic stress disorder (PTSD), Attention deficit hyperactivity disorder (ADHD), and a Non-Clinical Control Group on Tests of Attention and Inhibition

A pesar de que los niños con síndrome de estrés post-traumático (SEPT) y trastorno de déficit de atención e hiperactividad (TDA-H) manifiestan síntomas en común, se proponen diferencias en los mecanismos biológicos subyacentes en los estados de alerta, con características de un estado hiperalerta en el SEPT y de un estado hipoalerta en el TDA-H. Se administraron dos medidas de regulación de la atención: una tarea de atención sostenida (Vigil), utilizando tanto una condición con antelación (AK), como sin antelación (K), y la prueba Stroop de Comali-Kaplan, a tres grupos de niños: un grupo llenaba requisitos del DSM-IV para el diagnóstico de TDA-H, otro para el de SEPT, y un grupo control no tenía diagnóstico psiquiátrico. Hubo 15 participantes en cada grupo (N=45), con edades entre los 9 y 12 años, y con cociente intelectual en el K-BIT dentro del rango normal. Los resultados no arrojaron diferencias entre el grupo de TDA-H o el de SEPT en ninguna de las variables dependientes utilizadas: tiempos de respuesta y errores de omisión y comisión en la tarea de atención sostenida, así como tiempo para completar las tareas de la prueba Stroop. El grupo con TDA-H cometió más errores de omisión y comisión que el grupo control, mientras que el grupo con SEPT se distinguió del grupo control sólo en los errores de comisión. La antelación en Vigil produjo el efecto principal esperado, pero no mostró interacción con el factor grupo