In airway smooth muscle (ASM), adenosine 5'-triphosphate (ATP) induces a relaxation associated with prostaglandin production. We explored the role of K(+) currents (I (K)) in this relaxation. ATP relaxed the ASM, and this effect was abolished by indomethacin. Removal of airway epithelium slightly diminished the ATP-induced relaxation at lower concentration without modifying the responses to ATP at higher concentrations. ATPγS and UTP induced a concentration-dependent relaxation similar to ATP; α,β-methylene-ATP was inactive from 1 to 100 μM. Suramin or reactive blue 2 (RB2), P2Y receptor antagonists, did not modify the relaxation, but their combination significantly reduced this effect of ATP. The relaxation was also inhibited by N-ethylmaleimide (NEM; which uncouples G proteins). In myocytes, the ATP-induced I (K) increment was not modified by suramin or RB2 but the combination of both drugs abolished it. This increment in the I (K) was also completely nullified by NEM and SQ 22,536. 4-Amynopyridine or iberiotoxin diminished the ATP-induced I (K) increment, and the combination of both substances diminished ATP-induced relaxation. The presence of P2Y(2) and P2Y(4) receptors in smooth muscle was corroborated by Western blot and confocal images. In conclusion, ATP: (1) produces relaxation by inducing the production of bronchodilator prostaglandins in airway smooth muscle, most likely by acting on P2Y(4) and P2Y(2) receptors; (2) induces I (K) increment through activation of the delayed rectifier K(+) channels and the high-conductance Ca(2+)-dependent K(+) channels, therefore both channels are implicated in the ATP-induced relaxation; and (3) this I (K) increment is mediated by prostaglandin production which in turns increase cAMP signaling pathway.
Se muestra la evolución del movimiento de acceso abierto, en contraste con la resistencia de empresas editoriales que desean seguir controlando la distribución de la información científica a través del pago por publicar. Se presenta a los actores y el escenario donde se da esta disputa, con base en los antecedentes de la comunicación científica y de las diferentes etapas del proceso de acceso a las publicaciones especializadas. Se discute la relevancia y viabilidad del movimiento Open Access (AO), y se proporcionan algunas claves para su posible sustentabilidad. Se destaca la necesidad de replantear la dictaminación por pares de los artículos, a fin de alcanzar una revisión abierta (Open Review, OR), en un contexto generalizado de cultura libre. Se concluye que se trata de un fenómeno de carácter económico, social, político y epistémico, además de que la esencia del Open Access demanda un modelo de circulación libre, abierta y gratuita del conocimiento científico, en un contexto de prácticas colaborativas entre autores, editores, revisores y bibliotecarios, en el entendido de que el conocimiento es un bien común y que, por ello, es necesario definir nuevos patrones de producción, evaluación, distribución, consumo y propiedad del conocimiento.
The expression pattern of transforming growth factor beta (TGFβ) isoforms in chicken embryo gonads was studied at 6-10 days of incubation. TGFβ2 mRNA was expressed predominantly in the cortex of the left ovary from day 8 of incubation onwards. TGFβ3 mRNA was not detected at any of the stages studied. Similarly, immunofluorescence for the TGFβ protein revealed that at day 9 it was located throughout the cortex of the left ovary and in the medulla of both the left and right ovaries. The presence of phosphorylated Smad2 in the nuclei of these regions suggests that TGFβ signaling is most likely active at this developmental stage. Culturing the left ovary in a TGFβ1-supplemented medium induced a shift of cortical structures toward the medulla, suggesting a role for TGFβ in the morphogenesis of the female gonad in chickens.
This paper outlines some key lines of inquiry for the discussion of the conceptualization of the information/ knowledge society, from a social/theoretical perspective. Some elements of the so-called information society are discussed, such as: technology, economics, work, networks, etc…It is argued on the subject -often made-that recent technological changes have given rise to a different type of society, and if -indeed-this is a new model of society or if we have a new role of information in the same system, but in a different scenario. It highlights the fact that a new kind of society would mean that the (theoretical) knowledge will drive decision making in all areas of life.On the other hand, reference is made to both the ethical and ideological aspects of information to show that it is not an isolated phenomenon but responds to different contexts and interests. Also, it refers to the perspectives and approaches from which one can address this issue, since this is a multifaceted topic. Finally, it discusses the role of the librarian in this scenario.Keywords: Information, information society, knowledge society, librarianship, conceptualization. ResumenEn el presente trabajo se esbozan algunas líneas de reflexión fundamentales para la discusión en torno a la conceptualización de la sociedad de la información/conocimiento, desde una perspectiva teórico-social. Se plantean algunos elementos constitutivos de la llamada sociedad de la información, tales como: tecnología, economía, trabajo, redes, etcétera. Se discute sobre el tema -muchas veces formulado-de que los recientes cambios tecnológicos han dado origen a un tipo diferente de sociedad. Nos preguntamos si efectivamente estamos ante un nuevo modelo de sociedad o si nos encontramos ante una nueva función de la información en un mismo sistema, pero en un escenario distinto. Se destaca el hecho de que un nuevo tipo de sociedad implicaría que el conocimiento (teórico) impulsara la toma de decisiones en todos los ámbitos de la vida. Por otro lado, se hace referencia tanto al aspecto ético como ideológico de la información, para mostrar que no se trata de un fenómeno aislado sino que responde a diferentes contextos e intereses. De igual manera, se refieren las perspectivas o enfoques desde los que se puede abordar esta cuestión, ya que se trata de un tópico multifacético. Finalmente, se habla del rol del bibliotecario ante este panorama.Palabras clave: Información, sociedad de la información, sociedad del conocimiento, bibliotecología, conceptualización.
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