The c‐kit proto‐oncogen (CD117) has been described to be present in normal and neoplastic hemopoietic cells including both myeloid and lymphoid lineages. Among the normal lymphoid cells CD117 expression would be restricted to a small subset of NK‐cells, and to early T‐cell precursors and it is not expressed by normal B‐cells. Regarding chronic lymphoproliferative disorders the only data provided up to now suggests that CD117 expression is restricted to cases of Hodgkin's disease and anaplastic large‐cell lymphoma. In the present paper we describe a case of a B‐cell chronic lymphoproliferative disorder carrying the t(14:18) translocation as demonstrated by molecular studies, in which the flow cytometric immunophenotypic analysis of both peripheral blood and bone marrow samples revealed the expression of high amounts of the CD117 antigen in the surface of the clonal B‐cell population. Further studies are necessary to explore both the functional role of c‐kit expression in the neoplastic B‐cells from this patient and its potential utility for the diagnosis and follow‐up of patients with B‐cell non‐Hodgkin's lymphoma. Am. J. Hematol. 63:226–229, 2000. © 2000 Wiley‐Liss, Inc.
El objetivo del artículo es presentar criterios e indicadores de calidad para la evaluación del e-learning, fundamentados en el enfoque sociocultural, para su aplicación a programas de formación del profesorado en Tecnologías de la Informacióny la Comunicación. Enprimer lugar se ofrece una panorámica general sobre los principales enfoques evaluativos orientados a determinar la calidad de la formación virtual, o e-learning. En segundo término se presentan algunos constructos del enfoque sociocultural relevantes para la evaluación de los aprendizajes de la formación on-line. Y por último se muestra la derivación de estos constructos socioculturales a la creación de instrumentos evaluativos e indicadores de calidad de la formación en el aprendizaje (e-learning).
Esta aportación está vinculada a la difusión de los resultados de un proyecto de investigación titulado “Políticas educativas autonómicas y sus efectos sobre la innovación pedagógica en el uso de las TIC en los centros escolares”, que se ha desarrollado en el marco del Plan Nacional de I+D 2004-2007. El trabajo se centra en el análisis del discurso que explicita las políticas educativas en Andalucía, dirigidas a la incorporación de las TIC en el sistema educativo. El estudio realizado permite, por un lado, conocer y detallar los conceptos implícitos en las mismas respecto a “buenas prácticas” con TIC, innovación educativa con TIC, y usos de las TIC, y por otro, determinar los principales ámbitos de incidencia de la intervención política, así como los programas de incentivación relacionados con la innovación y buenas prácticas con TIC.
Clonal propagation of an Andean tuber `Achira' (Canna edulis Ker.) is currently limited to budding. A tissue-culture system to rapidly produce clonal material would be valuable for both production and germplasm preservation. Thirteen cultivars collected at the provinces of Cáqueza (Cundinamarca) and Garzón (Huila) were utilized for the establishment of meristem-tips (5 mm) under in vitro conditions. Based on protocols reported for species of Musa sp., C. indica and Elletaria cardamomun, a complete random design was implemented with 10 treatments and six replications per clone. The analysis of variance showed no significant differences between cultivars, but significant differences among treatments. The variables measured were number of shoots, aerial roots formation, roots (relative amount), callus (absent or present) and degree of etiolation. Double disinfestation protocol was used in this study in order to reduce the degree of contamination of the explants during the culture. Organogenesis was obtained for the whole cultivars, without callus formation, with treatments 9 and 10. However the best results for shoot and root formation was detected for the treatment 10. This was constituted by MS (1/2) supplemented with 0.1 ppm BAP; 0.5 ppm IBA; 3% sucrose, and 2% phytagel. The explants were grown at 26 °C with photoperiod of 16 hours and 2000 lux. After 3 weeks the shoot formation was evident, while the rooting started after 4 weeks. Subcultures were done every 3 weeks after plantlets formation. The 13 cultivars established under in vitro conditions were placed at the active genebank of the Plant Genetic Resources National Program at CORPOICA, for their conservation under low growth conditions.
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