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Estudio de diez polimorfismos - SNPs- en pacientes con enfermedad de Alzheimer (EA) en una muestra colombiana. Aproximación a genotipos haploides.
Get PDFLa enfermedad de Alzheimer (EA) es el tipo más común de demencia, descrita en 1907 por Alois Alzheimer; desde entonces ha sido objeto de extensa investigación básica y clínica debido a su alto impacto económico y social principalmente en países en desarrollo como Colombia. Basados en las diferencias poblacionales, los estudios de asociación buscan factores genéticos de susceptibilidad de enfermedades multifactoriales como la EA, en este tipo de estudios no es posible extrapolar los resultados de asociación ya que en cada población no solo se presentan diferencias genéticas sino que los individuos ven sometidos a diferentes factores ambientales que pueden contribuir al desarrollo de la patología. En este sentido, el Grupo de Neurociencias de la Universidad Nacional de Colombia, se ha encaminado en la búsqueda de factores genéticos relacionados con la EA en la población Colombiana. Se ha adelantando estudios de asociación en genes como BDNF, COMT, TAU, UCHL1, entre otros, sin tener resultados positivos de asociación aparte de la replicación de asociación de APOEe4 con la EA. Continúa la exploración de factores genéticos de susceptibilidad para la EA en la población Colombiana, basados en múltiples hipótesis explicativas de como el metabolismo de lípidos, estrés oxidativo, transporte y degradación que pueden dar explicación a las características propias de la EA. En los estudios caso-control realizados anteriormente en el Grupo se utilizaron técnicas como RFLPs las cuales tienen limitación en cuanto a tiempo de número de variantes evaluadas y especificad. Por la necesidad de avanzar en técnicas más costo-efectivas, en este trabajo se estandariza la técnica SNaPshot (Applied Biosystems) para 10 SNPs: CLU (rs11136000), PICALM (rs3851179), CR1 (rs665640), BIN1 (rs744373), TOMM40 (rs2075650), PVRL2 (rs6859), APOE (rs440446), SORL1 (rs11218304), CR1 (rs381861) y GWA_14q32.13 (rs11622883); permitiendo resultados más generalizables y robustos, acompañado de una disminución en costos y tiempo en comparación con otras técnicas de genotipificación. Los SNPs evaluados en este trabajo han sido relevantes en los últimos años debido a que se reportan asociados con el desarrollo de la EA en los GWAS y replicados en estudios caso-control en diferentes poblaciones. Debido a que en Colombia no se tienen reportes de estos SNPs potencialmente importantes para la EA, este proyecto tiene como propósito realizar un estudio caso-control con el fin identificar el riesgo de estas variantes génicas y establecer sus posibles interacciones en pacientes con EA en Colombia. Además de los SNPs, entendiendo la EA como una enfermedad multifactorial fueron evaluados otros factores no genéticos como la escolaridad, estado civil, género por análisis de correspondencia múltiple (ACM) y multifactor-dimensionality reduction (MDR), estos métodos permiten la identificación y correlación de factores genéticos y ambientales que pueden actuar como predictores de riesgo a la EA. En este estudio se encontró asociación significativa con APOEe4 en LOAD (OR: 14.74; CI: 0.838, 259.16) y EAOD (11.86; CI: 0.623, 225.63). En LOAD se encontró asociación con el polimorfismo TOMM40 (rs2075650) (OR: 3.869, CI: 2.12, 5.84; P: 4.656e-007) y GWArs11622883 (OR: 2.285, CI: 1.49, 3.48; P: 0.0001059). Así mismo se muestra una tendencia de asociación sin ser estadísticamente significativa en los SNPs BIN1rs744373 (OR: 1.519, CI: 0.94, 2.49; P. 0.08274), CLUrs2279590 (OR: 1.346, CI: 0.90,1.99; P: 0.1392) y CR1rs3818361 (OR: 1.385, CI: 0.81, 2.36; P: 0.232). Las diferencias encontradas aquí con los reportes en otras poblaciones quizás se deban a diferencias en el origen ancestral de los individuos evaluados, el tipo de análisis, los criterios de inclusión y exclusión de los individuos, la metodología usada en cada estudio, entre otras variables que pueden afectar de manera diferencial los resultados de los estudios de asociación genética. La combinación de genotipos con los SNPs asociados (TOMM40, APOEe4 y GWA_14q32.13) permitió establecer que la combinación GCA que contiene los tres alelos de riesgo para confiere un riesgo incrementado (OR: 6.00, CI: 2.45, 14.70; p: 1.1274E-5), sin embargo, el hecho de tener solamente los alelos de riesgo para TOMM40 y APOE e4 (GCT) confiere un riesgo aun mayor (OR: 9.97, CI: 2.28, 43.51; p: 1.0E-4), esto parece indicar que estos dos SNPs actúan de manera conjunta para producir EA en la muestra analizada. Igualmente, se determinó que el género y el estado civil se encontraban asociados positivamente con el diagnostico EA. Se encontró que el género se encontraba asociado con un p-valor (0.00593) y el estado civil con un p-valor de (8.353e-05) siendo este el más significativo de las variables analizadas. Los análisis de ACM y MDR muestran relación entre estado civil, escolaridad, TOMM40 y APOE, de manera que la combinación de estos factores podrían ser predictores de diagnostico EA. Los resultados aquí mostrados sugieren una asociación significativa con APOE, TOM40 y LOAD en población colombiana. Además, TOMM40 podría estar interactuando con APOE y factores de riesgo ambientales para modular el desarrollo de la EA en nuestra población. Al identificar estas variantes asociadas a EA en Colombia, sería necesario realizar futuras investigaciones para clarificar el mecanismo de acción o ruta metabólica mediante la cual estas variaciones están implicadas al riesgo de desarrollar este tipo de demencia. / Abstract. Alzheimer's disease (AD) is the most common dementia, described by Alois Alzheimer in 1907 and is important in extensive basic and clinical research because of its high economic and social impact mainly in developing countries such as Colombia. Based on population differences, association studies search genetic susceptibility to multifactorial diseases such as AD, in this studies is not possible to extrapolate the association results and each population differ not only genetic but individuals are subjected to different environmental factors that may contribute to the development of pathology. In this regard, the Group of Neurosciences, Universidad Nacional de Colombia, has been directed in the search for genetic factors associated with AD in the Colombian population. Association studies are addressed in genes such as BDNF, COMT, TAU, UCHL1, among others, without positive results of association in addition of replication ApoEe4 with AD. Continues the exploration of genetic susceptibility factors for AD in the Colombian population, based on multiple hypotheses to explain like lipid metabolism, oxidative stress, transport and degradation that can provide an explanation for the characteristics of AD. In case-control studies previously conducted in our Group as RFLP techniques were used which have a time limitation on number of variants assessed and specificity. By the need to advance cost-effective techniques, this work standardized SNaPshot technique (Applied Biosystems) for 10 SNPs: CLU(rs11136000), PICALM (rs3851179), CR1(rs665640), BIN1(rs744373), TOMM40(rs2075650), PVRL2 (rs6859), APOE(rs440446), SORL1(rs11218304), CR1(rs381861) and GWA_14q32.13(rs11622883), allowing more generalizable and robust results, accompanied by a decrease in costs and time compared with other genotyping techniques. The SNPs evaluated in this work have been important in recent years because they are reported associated with the development of AD in the GWAS and replicated in case-control studies in different populations. Because in Colombia there are no reports of these SNPs potentially important for AD, the aim here was conducted a case-control study to identify the risk of these genetic variants and to establish their possible interactions in patients with AD in Colombia . In addition to SNPs, understanding the EA as a multifactorial disease were evaluated non-genetic factors such as education, marital status, gender by multiple correspondence analysis (MCA) and multifactor dimensionality-reduction (MDR), these methods allow the identification and correlation genetic and environmental factors that can act as predictors of risk for AD. This study found significant association with LOAD ApoEe4 (OR 14.74, CI: 0.838, 259.16) and EAOD (11.86, CI: 0.623, 225.63). In association with LOAD was found TOMM40 polymorphism (rs2075650) (OR: 3,869, CI: 2.12, 5.84, P: 4.656e-007) and GWArs11622883 (OR: 2,285, CI: 1.49, 3.48, P: 0.0001059). It also shows a trend of association was not statistically significant in BIN1rs744373 SNPs (OR: 1,519, CI: 0.94, 2.49, P 0.08274), CLUrs2279590 (OR: 1.346, CI: 0.90, 1.99, P: 0.1392) and CR1rs3818361 (OR: 1,385, CI: 0.81, 2.36, P: 0.232). The differences found here with reports in other populations may be due to differences in the ancestry of individuals tested, the type of analysis, the criteria for inclusion and exclusion of individuals, the methodology used in each study, among other variables differentially affect the results of genetic association studies. The combination of genotypes associated SNPs (TOMM40, ApoEe4 and GWA_14q32.13) established that the combination GCA containing all three risk alleles conferred an increased risk (OR 6.00, CI: 2.45, 14.70, P = 1.1274E -5), however, having only the risk alleles for TOMM40 and APOE e4 (GCT) confers an even greater risk (OR 9.97, CI: 2.28, 43.51, P = 1.0E-4), this seems indicate that these two SNPs act together to produce EA in our sample. Also found that gender and marital status were positively associated with the diagnosis AD. It was found that gender was associated with a p-value (0.00593) and marital status with a p-value (8.353e-05) being the most significant of the variables analyzed. The MCA and MDR analysis shows relationship between marital status, education, and APOE TOMM40, so that the combination of these factors could be predictors of AD diagnosis. The results presented here suggest a significant association with APOE, TOM40 and LOAD in Colombian population. In addition, TOMM40 may be interacting with APOE and environmental risk factors to modulate the development of AD in our population. Identified these variants associated with AD in Colombia, future research would be needed to clarify the mechanism of action or metabolic pathway by which these variations are involved the risk of developing this type of dementia.Maestrí
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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