933 resultados para Intermediation in development


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Background: Activation of the sympathetic nervous system (SNS) in response to chronic biobehavioral stress results in high levels of catecholamines and persistent activation of adrenergic signaling, which promotes tumor growth and progression. However it is unknown how catecholamine levels within the tumor exceed systemic levels in circulation. I hypothesized that neo-innervation of tumors is required for stress-mediated effects on tumor growth. Results: First, I examined whether sympathetic nerves are present in human ovarian cancer samples as well as orthotopic ovarian cancer models. Immunohistochemical (IHC) staining for neurofilament revealed that catecholaminergic neurons are present within tumor tissue. In order to determine whether chronic stress affects the density of nerves in the tumor, I utilized an orthotopic mouse model of ovarian cancer that was exposed to daily restraint stress. IHC analysis revealed that nerve density in tumors increased by more than three-fold in stressed animals versus non-stressed controls. IHC analysis suggested that this results from both recruitment of existing neurons (axonogenesis) as well as new neuron formation (neurogenesis) within the tumor. To determine how tumors are recruiting nerve growth, I utilized a PCR array analysis of 84 nerve growth related genes and their receptors, which showed that stimulation of the SKOV3 ovarian cancer cell line with norepinephrine (NE) leads to increased expression of several neurotrophins, including brain-derived neurotrophic factor (BDNF). Neurite extension assays showed that media conditioned by ovarian cancer cell lines is capable of inducing neurite outgrowth in differentiated neuron-like PC12 cells, and NE treatment of cancer cells potentiates this effect. Norepinephrine-induced neurite extension was abolished after BDNF silencing by siRNA, suggesting that BDNF is critical to tumor cell-induced nerve growth. in vivo BDNF inhibition resulted in complete abrogation of stress-induced increases in tumor weight and nerve density, as well as downstream markers of stress. Discussion: These studies indicate that adrenergic signalling induced by chronic stress promotes neo-innervation in the tumor microenvironment. This results in a mutually beneficial relationship between the tumor cells and neurons. This work is crucial for providing a link between chronic stress and its effects on the tumor and its microenvironment. The data shown here aims to open new venues that can be used in development of therapies designed to block the stress effects on tumor growth.

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Potent vaccine formulations ideally include adjuvants to activate innate immune responses and enhance antigen-specific adaptive immunity. The synthetic glycolipid alpha-Galactosylceramide (α-GalCer) effectively activates the innate immune mediating NKT cells to produce cytokines and activate downstream immune cells, resulting in development of humoral and cell mediated immune responses to co-administered antigens. While a single intravenous immunization of α-GalCer strongly activates NKT cells, multiple doses by this route are well documented to induce anergy in NKT cells. Anergy is defined as the deficiency in NKT proliferation and cytokine production, including IL-4 and IFNγ. However, our studies have shown that two doses of α-GalCer administered intranasally by the intranasal route leads to reactivation of NKT cells and improved adaptive immune responses after each subsequent dose. I therefore investigated the role of multiple routes of immunization in activation of NKT cells, i.e. anergy versus repeated activation. Specifically, I hypothesized that the differential capacity of NKT cells to produce IFNγ, as a result of route of immunization with α-GalCer, influences the induction of adaptive immune responses to co-administered antigen. Our experimental design utilizes the observation that intranasal immunization primarily induces immune responses in the lungs while intravenous immunization induces responses in the liver. Using intracellular cytokine staining for IFNγ production and Elispot analyses for determining NKT and T cell activation, respectively, it was determined that administering two consecutive intravenous doses resulted in anergy to NKT cells (no IFNγ production) in the liver and lack of adaptive immunity while second immunization by the intranasal route overcame anergy in the lung. The outcome in the other tissues analyzed was mixed and could be the result of tissue microenvironment among others possible reasons. When intranasal dosing preceded systemic, NKT cells were reactivated to produce IFNγ and induced positive adaptive immune responses in the responding lung tissue. These results indicate that the mechanism by which mucosal and systemic immunization routes activate NKT cells may differ in that there is a differential tissue-specific effect induced by each route. Future studies are necessary to determine the reason for these tissue-specific effects and how they relate to NKT cell activation.

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The non-Hodgkin's B cell lymphomas are a diverse group of neoplastic diseases. The incidence rate of the malignant tumors has been rising rapidly over the past twenty years in the United States and worldwide. The lack of insight to pathogenesis of the disease poses a significant problem in the early detection and effective treatment of the human malignancies. These studies attempted to investigate the molecular basis of pathogenesis of the human high grade B cell non-Hodgkin's lymphomas with a reverse genetic approach. The specific objective was to clone gene(s) which may play roles in development and progression of human high grade B cell non-Hodgkin's lymphomas.^ The messenger RNAs from two high grade B cell lymphoma lines, CJ and RR, were used for construction of cDNA libraries. Differential screening of the derived cDNA libraries yielded a 1.4 kb cDNA clone. The gene, designated as NHL-B1.4, was shown to be highly amplified and over-expressed in the high grade B cell lymphoma lines. It was not expressed in the peripheral blood lymphoid cells from normal donors. However, it was inducible in peripheral blood T lymphocytes by a T cell mitogen, PHA, but could not be activated in normal B cells by B cell mitogen PMA. Further molecular characterization revealed that the gene may have been rearranged in the RR and some other B cell lymphoma lines. The coding capacity of the cDNA has been confirmed by a rabbit reticulocyte lysate and wheat germ protein synthesis system. A recombinant protein with a molecular weight of approximate 30 kDa was visualized in autoradiogram. Polyclonal antisera have been generated by immunization of two rabbits with the NHL-B1.4 recombinant protein produced in the E. coli JM109. The derived antibody can recognize a natural protein with molecular weight of 49 kDa in cell lysate of activated peripheral T lymphocytes of normal donors and both the cell lysate and supernatant of RR B cell lymphoma lines. The possible biologic functions of the molecule has been tested preliminarily in a B lymphocyte proliferation assay. It was found that the Q-sepharose chromatograph purified supernatant of COS cell transfection could increase tritiated thymidine uptake by B lymphocytes but not by T lymphocytes. The B cell stimulatory activity of the supernatant of COS cell tranfection could be neutralized by the polyclonal antisera, indicating that the NHL-B1.4 gene product may be a molecule with BCGF-like activity.^ The expression profiles of NHL-B1.4 in normal and neoplastic lymphoid cells were consistent with the current B lymphocyte activation model and autocrine hypothesis of high grade B cell lymphomagenesis. These results suggested that the NHL-B1.4 cDNA may be a disease-related gene of human high grade B cell lymphomas, which may codes for a postulated B cell autocrine growth factor. ^

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The Retinoblastoma tumor suppressor gene (RB) plays a role in a variety of human cancers. Experimental analyses have indicated that the protein product of the RB gene (pRb) plays a role in cell cycle regulation, and that this protein is required in cellular differentiation, senescence, and cell survival. pRb function is dependent on its ability to bind to cellular factors. There are multiple protein binding domains within pRb. Mutations within these domains which eliminate the ability of pRb to bind its targets result in loss of function. Loss of pRb function leads to tumorigenesis, although uncontrolled cellular proliferation is not a universal response to pRb inactivation. The ultimate response to the loss of pRb is influenced by both the genetic and epigenetic environments. Targeted disruption of RB in mice results in embryonic lethality, demonstrating the requirement for functional pRb in development. Close examination of various tissues from the embryos which lack wildtype RB shows problems in differentiation as well as showing induction of apoptosis. Although disruption of RB has provided useful information, complete inactivation of a gene precludes the possibility of discovering the functions that separate domains may have within the system. Creation of a dominant negative mutant by domain deletion whose phenotype is expressed in the presence of the wildtype may provide information about the intermediate functions of the protein. In addition, tissue specific targeting of a dominant negative mutant of pRb allows for comprehensive analysis of pRb function in organogenesis. In this thesis, a series of RB deletion mutants were created and tested for dominant negative activity as well as cellular localization. A tissue culture assay for dominant negative activity was developed which screens for the phenotype of apoptosis due to loss of pRb function. Two mutants from this series scored positive for dominant negative activity in this assay. The effect of these mutants within the assay environment can be explained by a model in which pRb acts as a facilitator of cell fate pathway decisions. ^

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We studied the response in development times of Calanus finmarchicus and Calanus helgolandicus to changes in temperature and food conditions. The ingestion response to temperature was determined in the laboratory, where the copepods C. finmarchicus and C. helgolandicus were fed the diatom Thalassiosira weissflogii (cultivated at 18°C-20°; 12 : 12 light :dark cycle; exponential growth). C. finmarchicus was obtained for experiments from the Gullmar fjord. C. finmarchicus was incubated at in situ temperature (5°C) until the experiments were performed. First-generation cultures were grown in the laboratory at 15°C from the eggs from the Sta. L4 females. During growth both C. finmarchicus and C. helgolandicus cultures were fed a mixture of the cryptophyte Rhodomonas salina, the diatom Thalassiosira weissflogii, and the dinoflagellate Prorocentrum minimum. Five 600-mL glass bottles containing 1400 cells mL**-1 or 5 mg chlorophyll a (Chl a) L**-1 of T. weissflogii (200 mg C) and 1-2 C. finmarchicus or C. helgolandicus copepodite stage 5 (CV) or females were incubated in darkness at series of temperatures between 1°C and 21 ± 0.5°C. Three bottles without copepods served as control. In the C. helgolandicus experiment, T. weissflogii cells were counted at the beginning and end of the experiment in the grazing bottles and controls using a Coulter CounterH (MultisizerTM 3, Beckman Coulter). In the C. finmarchicus experiment, phytoplankton reduction was determined by Chl a measurements. The reduction in phytoplankton during any of the experiments was generally below 20% and never more than 32%. Clearance rates were calculated following Harris et al. (2000).

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La cultura se presenta hoy como un elemento determinante en la planificación del desarrollo, tanto por los efectos económicos que genera en términos de empleo, ingresos, y producción; como por ser un instrumento útil y eficaz para el fortalecimiento de la independencia, la soberanía y la identidad de los territorios en un mundo globalizado. El objetivo de este estudio es reconocer el impacto de la cultura en el desarrollo económico a través de un ejercicio empírico centrado en el Museo de Antioquia de la ciudad de Medellín (Colombia). Se aplicó una encuesta de percepción a los habitantes y visitantes de la ciudad. Los datos se sometieron a un análisis descriptivo y se formalizó un Modelo de Regresión Logística en busca de identificar y explicar los elementos que permiten vincular la cultura y el desarrollo. Se encontró que cerca al 90% de los encuestados afirmaron que la existencia del Museo de Antioquia es importante para el desarrollo económico de la ciudad de Medellín, identificándolo como un atractivo turístico y cultural que genera impactos positivos en el crecimiento económico y el bienestar social.

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yResults of 13 field investigations between 1966 and 1990 of the southwestern to eastern margin of Kötlujökull and its proglacial area are summarized with respect to sandar and their formation. Generally, the results are based on sedimentological examinations in the field and laboratory, on analyses of aerial photographs, and investigations of the glacier slope. The methods permitted a more detailed reconstruction of sandar evolution in the proglacial area of Kötlujökull since 1945, of tendencies in development and of single data going back until the last decades of the 19th century. Accordingly, there existed special periods of "flachsander"-formations with raised coarsegrained "sanderwurzels" resultant from the outbreak of subglacial meltwater tunneloutlets and other periods with "hochsander-"formations by supraglacial drainage. At present the belts of hochsanders in front of the glacier come up to more than 4 m in thickness and 1000 m in width, therefore containing perhaps more sediment direct in front of Kötlujökull than the old belts of flachsanderwurzels. In one case the explosion-like subglacial meltwater outburst combined with the genesis of a sanderwurzel could be observed for a time and is thoroughly discussed. The event is referred to the outburst of a sub- to inglacial meltwater body being under extreme hydrostatic press ures which is combined with the genesis of a new subglacial tunneloutlet as a new flachsander. Often these outbursts led to the destruction of a morainic belt more than 1000 m in width. Presumably the whole event was finished in not more than a few days. In addition to a characteristic pear-shaped form and water-moved stones up to diameters of 1 m the wurzels possess a single "main-channel" with rectangular cross-sections as far as 4 m deep and 50 m wide just as small flat channels resembling fish bones in connection with the main channel. Presumably, they have been active only in the last stage of wurzel formation. With regard to the subglacial tunnel gates long-living L-meltwater outlets are distinguished from short-living K-meltwater outlets. These are always combined with a raised coarse-grained sanderwurzel, but its meltwater discharge is generally decreasing and ceases after some years, whereas the discharge of L-meltwater outlets continues unchanged for long times (except seasonal differences). The material of flachsanders is preponderantly composed of mugearitic and andesitic cobble extending at least for some kilometres from the glacier margin, whereas the hochsanders correspond to medium to coarse sands without clay and without alternations into the direction of flow. The hochsander fans are covered with small braidet channels. Their sedimentary structures are determined by the short time changing of supraglacial meltwater discharge and the upper flow regime combined with the development of antidunes, which rule the channel-flows during the main activity periods in summer. Unlike the subglacial drainage the supraglacial drainage led to only weak effects of erosion on the glacier foreland. So the hochsanders refilled depressions of morainic areas or grew up on older flachsanderwurzels. Whereas all large flachsanders developed in front of approximate stationary glacier margins, the evolution of coherent belts of hochsanders were combined with progressive glacier fronts. On the other hand, there was obviously no evolution at all of large sandar in front of back-melting margins of Kötlujökull. Based on examinations of the glacier surface and on analyses of aerial photographs the different types of sandar are referred to different structures of the glacier snout. Finally chances of surviving of sandar in the proglacial area of Kötlujökull are shortly discussed just as the possibility of an application of the Islandic research results on Pleistocene sandar in northern Germany.

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Este trabajo examina los marcos epistémicos y su modus operandi sobre los modelos explicativos en la psicología del desarrollo. En primer lugar, los rasgos del marco epistémico de la escisión y su intervención en el modo ?legítimo? de explicar las competencias, habilidades y funciones psicológicas. En segundo lugar, se muestran las dificultades de dicho modelo, aún predominante entre los investigadores, cuando se pretende dar cuenta de la emergencia de comportamientos, sistemas conceptuales y funciones que son estrictamente novedosas, esto es, que no están dadas dentro del aparato mental ni fuera del propio proceso. En tercer lugar, se exploran las características de una explicación sistémica para dichas novedades, enmarcándola en una ontología y una epistemología relacional. Se identifican las características del modelo sistémico y se evalúa su eficacia respecto de la emergencia de sistemas conceptuales y funciones psicológicas nuevas en el desarrollo. Finalmente, se identifican dos versiones de dicha explicación: el sistema complejo del constructivismo y la perspectiva vigotskyana de la explicación, estableciendo una fuerte diferencia respecto de un sistema de interacciones no dialéctico

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This paper examines the association in a rural mining town in Brazil. The results belong to a master dissertationin Rural Extension on membership organizations and public policies for rural areas aiming to identify the roles performed by membership organizations, the reasons that explained their formation and their relationship with policy making for rural areas in the case studied. It is a case study, for which interviews were conducted with representatives of the organizations in order to deepen into the issues related to their historical, the roles they play and how and whether they participate in development project proposals. The results revealed anup-down process of formation of rural organizations, being created as bargaining tools for achieving collective benefits, reproducing dependency relationships

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El "Informe Altimir" es un trabajo solicitado por el Consejo Federal de Inversiones (CFI) a un equipo de investigadores dirigido por Oscar Altimir, para ser entregado a la Asesoría de Desarrollo de Chubut en 1970.Su objetivo era planificar las acciones para la instalación del modelo de "polos de desarrollo" así como analizar las políticas a seguir en las otras áreas económicas. A través de una revisión exhaustiva de esta fuente, y de su cruce con otros aportes, mostramos cuáles fueron las políticas agrarias que se impulsaron en Chubut.Se dividió la provincia en regiones, para impulsar un proyecto que buscara asegurar el suministro de alimentos a las áreas urbanas, la provisión de mano de obra para las industrias a instalarse y la concentración de la propiedad en el resto de Chubut.

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This study examines how the youth's Professional projects in new generation of family farmers are prepared and the perspective of reproduction of the familiar mode of production. The sociological task is to specify the distinctive features of the situation of the youth in family farming, seeking to identify the elements considered in the preparation of their professional projects. Qualitative data were produced by a case study of young farmers who lives in the city of Faxinal do Soturno, a municipality belonging to the fourth colony of Italian immigration in Rio Grande do Sul/Brazil. We performed 36 interviews, consisting of open questions, adopting a semi-structured script, wich were examined by de method of content analysis. Among the results, were observed a context marked by professional projects that breaks with the succession of the family farm work. The negative ratings on agricultural work stand out, particularly on issues related to health, salubrity of work and conditions of aging in rural areas. Family and emotional issues, and also specific aspects of the juvenile condition, marked by the pursuit of autonomy and emancipation, permeate the professional projects in development and show a complex analytical framework, wich amplify the explanatory factors of migration of youth.

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This paper examines the association in a rural mining town in Brazil. The results belong to a master dissertationin Rural Extension on membership organizations and public policies for rural areas aiming to identify the roles performed by membership organizations, the reasons that explained their formation and their relationship with policy making for rural areas in the case studied. It is a case study, for which interviews were conducted with representatives of the organizations in order to deepen into the issues related to their historical, the roles they play and how and whether they participate in development project proposals. The results revealed anup-down process of formation of rural organizations, being created as bargaining tools for achieving collective benefits, reproducing dependency relationships

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Este trabajo examina los marcos epistémicos y su modus operandi sobre los modelos explicativos en la psicología del desarrollo. En primer lugar, los rasgos del marco epistémico de la escisión y su intervención en el modo ?legítimo? de explicar las competencias, habilidades y funciones psicológicas. En segundo lugar, se muestran las dificultades de dicho modelo, aún predominante entre los investigadores, cuando se pretende dar cuenta de la emergencia de comportamientos, sistemas conceptuales y funciones que son estrictamente novedosas, esto es, que no están dadas dentro del aparato mental ni fuera del propio proceso. En tercer lugar, se exploran las características de una explicación sistémica para dichas novedades, enmarcándola en una ontología y una epistemología relacional. Se identifican las características del modelo sistémico y se evalúa su eficacia respecto de la emergencia de sistemas conceptuales y funciones psicológicas nuevas en el desarrollo. Finalmente, se identifican dos versiones de dicha explicación: el sistema complejo del constructivismo y la perspectiva vigotskyana de la explicación, estableciendo una fuerte diferencia respecto de un sistema de interacciones no dialéctico

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This paper examines the association in a rural mining town in Brazil. The results belong to a master dissertationin Rural Extension on membership organizations and public policies for rural areas aiming to identify the roles performed by membership organizations, the reasons that explained their formation and their relationship with policy making for rural areas in the case studied. It is a case study, for which interviews were conducted with representatives of the organizations in order to deepen into the issues related to their historical, the roles they play and how and whether they participate in development project proposals. The results revealed anup-down process of formation of rural organizations, being created as bargaining tools for achieving collective benefits, reproducing dependency relationships

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El "Informe Altimir" es un trabajo solicitado por el Consejo Federal de Inversiones (CFI) a un equipo de investigadores dirigido por Oscar Altimir, para ser entregado a la Asesoría de Desarrollo de Chubut en 1970.Su objetivo era planificar las acciones para la instalación del modelo de "polos de desarrollo" así como analizar las políticas a seguir en las otras áreas económicas. A través de una revisión exhaustiva de esta fuente, y de su cruce con otros aportes, mostramos cuáles fueron las políticas agrarias que se impulsaron en Chubut.Se dividió la provincia en regiones, para impulsar un proyecto que buscara asegurar el suministro de alimentos a las áreas urbanas, la provisión de mano de obra para las industrias a instalarse y la concentración de la propiedad en el resto de Chubut.