1,720,962 research outputs found
Estrategias de combinación de citoquinas con nutracéuticos para el tratamiento del carcinoma hepatocelular: suplementación con δ-tocotrienol o quercetina a una terapia con interferon α-2b
No full textEl carcinoma hepatocelular (HCC) es la tercera causa más común de muerte por cáncer en
todo el mundo, representando el 70-85% de todos los cánceres de hígado.
El interferón α (IFN α) se ha utilizado históricamente para evitar la progresión del daño
hepático, así como para la prevención de la progresión del HCC en pacientes con hepatitis
B o C crónica. Algunos estudios informaron una fuerte actividad antitumoral de IFN α y
una mejora en la tasa de supervivencia de pacientes con HCC cuando se administra en
combinación con otras terapias de apoyo.
Los nutracéuticos son alimentos de origen natural que proveen beneficios medicinales o
saludables. Dentro de los mismos se encuentran los tocotrienoles, isómeros de la vitamina
E, y la quercetina, el flavonoide más abundante procedente del metabolismo secundario
de los vegetales. El δ-tocotrienol presenta, entre todas las isoformas naturales de la
vitamina E, las actividades antiproliferativas más potentes contra varios tipos de cáncer,
in vitro e in vivo; también presenta la mayor citotoxicidad en células cancerígenas y es el
más antiangiogénico. Por otro lado, la quercetina tiene efectos quimiopreventivos en
modelos animales de hepatocarcinogénesis, y se evidenció que posee propiedades
antiangiogénicas in vitro e in vivo, como también capacidades antiproliferativas.
En base a esto, se decidió estudiar la suplementación con δ-tocotrienol o quercetina a una
terapia con IFN α y evaluar si existe algún efecto beneficioso entre estos compuestos en
el tratamiento del HCC, utilizando diferentes modelos experimentales in vitro, y
analizando el posible mecanismo implicado.
Se utilizaron 2 líneas celulares: SK-HEP-1 y Huh7, ambas de HCC humano, a las cuales se
les aplicaron los tratamientos individuales con IFN α-2b (grupo IFN), δ-tocotrienol (grupo
E) y quercetina (grupo Q) y posteriormente se realizaron las combinaciones, IFN α + δ-
tocotrienol (grupo IE) y IFN α + quercetina (grupo IQ). Las dosis utilizadas fueron: 10000
UI/ml y 20000 UI/ml de IFN α para las células SK-HEP-1 y Huh7 respectivamente, 25 uM
de δ-tocotrienol para ambas células y 12,5 uM de quercetina para las células SK-HEP-1.
Se evaluó el impacto de los tratamientos individuales y combinados sobre la viabilidad,
migración e invasión celular. Ambas combinaciones resultaron ser beneficiosas,
disminuyendo dichos procesos significativamente respecto a cada tratamiento individual.
A dichos estudios se sumaron el análisis de los cambios en la expresión de las proteínas
que actúan como reguladores críticos para el destino de las células cancerosas, como el antígeno nuclear de proliferación celular (PCNA), y las metaloproteinasas de matriz MMP-
7 y MMP-9, las cuales disminuyeron cuando las células se trataron con las combinaciones
de los compuestos en estudio.
Luego se demostró que los compuestos IFN α y δ-tocotrienol aumentaron la apoptosis a
través de la vía mitocondrial en células SK-HEP-1 y Huh7, tanto individualmente como
cuando se combinaron. Por otra parte, la quercetina no aumentó la apoptosis en células
SK Hep-1; sin embargo, cuando se combinó con IFN α el aumento de la muerte celular por
apoptosis fue significativamente mayor respecto al tratamiento individual.
Con el fin de estudiar los mecanismos implicados en los efectos observados, se demostró
que la combinación de IFN α con δ-tocotrienol actúa a través de la modulación de la vía
Erk de las proteínas quinasas activadas por mitógenos (MAPK), de la generación de
especies reactivas del oxígeno (EROs), e induce cambios en la expresión de la vía
p38/MAPK y Notch. Por otro lado, la combinación de IFN α con quercetina actúa a través
de la vía p38/MAPK en combinación con la generación de EROs.
Por último, se evaluó el impacto de los tratamientos individuales y combinados sobre la
angiogénesis, utilizando el modelo in vivo de la membrana corioalantoidea de pollo,
demostrando que ambos tratamientos combinados producen una disminución en la
formación de vasos sanguíneos nuevos, siendo esta disminución de mayor magnitud a la
observada con los tratamientos individuales.
En resumen, demostramos que tanto la suplementación con δ-tocotrienol como con
quercetina a una terapia con IFN α potencia los efectos antitumorales de la citoquina
contra las células de HCC, reduciendo la proliferación celular, la invasividad, la
angiogénesis y aumentando la muerte celular apoptótica. En este sentido, un enfoque de
tratamiento que utilice inmunoquímicos junto con productos naturales, como los
utilizados en nuestro estudio, podría contribuir a establecer nuevas propuestas
terapéuticas para el tratamiento del HCC.Fil: Lucci, Alvaro. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental (IFISE-CONICET); Argentina
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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