Papers by MARIA ISABEL ELJURI JARAMILLO
Journal of Hispanic Higher Education, 2013
Ecuador’s system of higher education is undergoing rapid and invasive changes. The national gover... more Ecuador’s system of higher education is undergoing rapid and invasive changes. The national government has used the Constitution of 2008 and the Higher Education Law of 2010 to change the way Ecuador’s universities are funded, administered and accredited. The importance of research has been elevated and drastic changes have been made to the academic qualifications and employment conditions of full-time faculty members. This article describes this attempt to bring Ecuador’s system of higher education more in line with its neighbors.
RESUMEN: Este artículo presenta un estudio llevado a cabo entre ejecutivos de los sectores empres... more RESUMEN: Este artículo presenta un estudio llevado a cabo entre ejecutivos de los sectores empresariales de Hotelería, Gastronomía y Turismo de las tres principales ciudades del Ecuador, para determinar sus percepciones sobre la educación superior en estas carreras. A través de varias entrevistas grupales, el estudio investigó lo que los ejecutivos y gerentes en Cuenca, Guayaquil y Quito pensaban sobre el valor de un título académico, la importancia y el formato de las prácticas estudiantiles, los contenidos de los programas de estudio, la relación entre las empresas y la academia, y el perfil de un graduado ideal. A pesar de haber diferencias de opinión, los ejecutivos identificaron una fuerte orientación al servicio, experiencia laboral, sólidas habilidades técnicas y un excelente manejo del idioma inglés, como componentes esenciales en el perfil de un graduado. Los participantes fueron francos sobre el valor de un título universitario y sobre el contenido de los programas académicos; identificaron deficiencias en las ofertas académicas actuales y ofrecieron valiosas sugerencias. ABSTRACT: This article reports on a study that was conducted among hotel management, gastronomy and tourism industry managers and executives of the three main cities of Ecuador to determine their perceptions about hospitality and tourism higher education. By means of several group interviews the study investigated what executives and managers in Cuenca, Guayaquil and Quito thought
Individual cancer cells carry a bewildering number of distinct genomic alterations i.e., copy num... more Individual cancer cells carry a bewildering number of distinct genomic alterations i.e., copy number variations and mutations, making it a challenge to uncover genomic-driven mechanisms governing tumorigenesis. Here we performed exome-sequencing on several breast cancer cell lines which represent two subtypes, luminal and basal. We integrated this sequencing data, and functional RNAi screening data (i.e., for identifying genes which are essential for cell proliferation and survival), onto a human signaling network. Two subtype-specific networks were identified, which potentially represent core-signaling mechanisms underlying tumorigenesis. Within both networks, we found that genes were differentially affected in different cell lines; i.e., in some cell lines a gene was identified through RNAi screening whereas in others it was genomically altered. Interestingly, we found that highly connected network genes could be used to correctly classify breast tumors into subtypes based on genomic alterations. Further, the networks effectively predicted subtype-specific drug targets, which were experimentally validated.
Http Dx Doi Org 10 1089 Oli 2006 16 2, Apr 3, 2006
Gene silencing is an essential tool in gene discovery and gene therapy. Traditionally, viral deli... more Gene silencing is an essential tool in gene discovery and gene therapy. Traditionally, viral delivery of antisense RNA and, more recently, small interfering RNA (siRNA) molecules in the form of small hairpin RNAs (shRNA) has been used as a strategy to achieve gene silencing. Nevertheless, the enduring challenge is to identify molecules that specifically and optimally silence a given target gene. In this study, we tested a set of adenovirus-delivered antisense RNA fragments and adenovirus-delivered shRNA molecules for their ability to target human transforming growth factor-beta type II receptor (TGFbetaRII). We used a dicistronic reporter, consisting of the coding sequences for TGFbetaRII and green fluorescent protein (GFP) to screen for optimal silencing agents targeting TGFbetaRII. Our results show, for both antisense RNA and shRNA molecules, that their effectiveness in the GFP screen correlated directly with their ability to reduce exogenously expressed TGFbetaRII. Unexpectedly, the antisense RNAs were unable to silence endogenous TGFbetaRII. In contrast, the shRNAs were able to silence endogenous TGFbetaRII. The shRNA that demonstrated the most pronounced effect on the dicistronic TGFbetaRII/GFP reporter reduced endogenous TGFbetaRII protein expression by 70% in A549 cells and reduced TGFbeta signaling by >80% in HeLa cells.
Entramado, Dec 1, 2012
Este artículo, basado en "El inventario de funciones del Voluntariado -IFV-", determina cuáles so... more Este artículo, basado en "El inventario de funciones del Voluntariado -IFV-", determina cuáles son las variables que motivan a los voluntarios en Colombia, a desarrollar las actividades relacionadas con el voluntariado. Se consideraron seis dimensiones (valores, carrera, social, comprensión, protección y mejora). El análisis de los resultados muestra que los voluntarios en Colombia se motivan principalmente porque pueden trabajar por una causa que es importante para ellos y porque pueden ayudar a los menos afortunados; variables pertenecientes a la dimensión de valores.
Oligonucleotides, 2006
Gene silencing is an essential tool in gene discovery and gene therapy. Traditionally, viral deli... more Gene silencing is an essential tool in gene discovery and gene therapy. Traditionally, viral delivery of antisense RNA and, more recently, small interfering RNA (siRNA) molecules in the form of small hairpin RNAs (shRNA) has been used as a strategy to achieve gene silencing. Nevertheless, the enduring challenge is to identify molecules that specifically and optimally silence a given target gene. In this study, we tested a set of adenovirus-delivered antisense RNA fragments and adenovirus-delivered shRNA molecules for their ability to target human transforming growth factor-beta type II receptor (TGFbetaRII). We used a dicistronic reporter, consisting of the coding sequences for TGFbetaRII and green fluorescent protein (GFP) to screen for optimal silencing agents targeting TGFbetaRII. Our results show, for both antisense RNA and shRNA molecules, that their effectiveness in the GFP screen correlated directly with their ability to reduce exogenously expressed TGFbetaRII. Unexpectedly, the antisense RNAs were unable to silence endogenous TGFbetaRII. In contrast, the shRNAs were able to silence endogenous TGFbetaRII. The shRNA that demonstrated the most pronounced effect on the dicistronic TGFbetaRII/GFP reporter reduced endogenous TGFbetaRII protein expression by 70% in A549 cells and reduced TGFbeta signaling by >80% in HeLa cells.
Early embryonic stem cell differentiation is marked by the formation of 3 germ layers with distin... more Early embryonic stem cell differentiation is marked by the formation of 3 germ layers with distinct molecular markers from which all tissues types will arise. Most of these in-vitro inductions are achieved through modulations of the cellular chemical microenvironment . Recently, researchers are studying the effect of mechanical cues such as matrix elasticity on stem cell differentiation. In this study, we are reporting how the cellular mechanical microenvironment affects the differentiation and phenotypic commitment of embryonic stem cells. The mechanical environment was modulated by culturing the cells on a fibrin hydrogel matrix, and subsequently modifying the gelation characteristics to vary the mechanical properties of the fibrin substrate. The selection criteria for the materials were to use a substrate that would promote cell attachment, whose chemistry can be easily manipulated to achieve different mechanical properties, while also maintaining chemical equivalence. The mechan...
Tissue engineering. Part A, 2015
It is well recognized that in vitro differentiation of embryonic stem cells (ESC) can be best ach... more It is well recognized that in vitro differentiation of embryonic stem cells (ESC) can be best achieved by closely recapitulating the in vivo developmental niche. Thus, implementation of directed differentiation strategies has yielded encouraging results in the area of pancreatic islet differentiation. These strategies have concentrated on direct addition of chemical signals, however, other aspect of the developmental niche are yet to be explored. During development, pancreatic progenitor (PP) cells grow as an epithelial sheet, which aggregates with endothelial cells (ECs) during the final stages of maturation. Several findings suggest that the interactions with EC play a role in pancreatic development. In this study, we recapitulated this phenomenon in an in vitro environment by maturing the human ESC (hESC)-derived PP cells in close contact with ECs. We find that co-culture with different ECs (but not fibroblast) alone results in pancreatic islet-specific differentiation of hESC-de...
Angiogenesis, 2014
An alternative or follow-up adjunct to conventional maximum tolerated dose (MTD) chemotherapy now... more An alternative or follow-up adjunct to conventional maximum tolerated dose (MTD) chemotherapy now in advanced phase III clinical trial assessment is metronomic chemotherapy-the close regular administration of low doses of drug with no prolonged breaks. A number of preclinical studies have shown metronomic chemotherapy can cause long term survival of mice with advanced cancer, including metastatic disease, in the absence of overt toxicity, especially when combined with targeted antiangiogenic drugs. However, similar to MTD chemotherapy acquired resistance eventually develops, the basis of which is unknown. Using a preclinical model of advanced human ovarian (SKOV-3-13) cancer in SCID mice, we show that acquired resistance can develop after terminating prolonged (over 3 months) successful therapy utilizing daily oral metronomic topotecan plus pazopanib, an oral antiangiogenic tyrosine kinase inhibitor (TKI). Two resistant sublines were isolated from a single mouse, one from a solid tumor (called KH092-7SD, referred to as 7SD) and another from ascites tumor cells (called KH092-7AS, referred to as 7AS). Using these sublines we show acquired resistance to the combination treatment is due to tumor cell alterations that confer relative refractoriness to topotecan. The resistant phenotype is heritable, associated with reduced cellular uptake of topotecan and could not be reversed by switching to MTD topotecan or to another topoisomerase-1 inhibitor, CPT-11, given either in a metronomic or MTD manner nor switching to another antiangiogenic drug, e.g. the anti-VEGFR-2 antibody, DC101, or another TKI, sunitinib. Thus, in this case cross resistance seems to exist between MTD and metronomic topotecan, the basis of which is unknown. However, gene expression profiling revealed several potential genes that are stably upregulated in the resistant lines, that previously have been implicated in resistance to various chemotherapy drugs, and which, therefore, may contribute to the drug resistant phenotype.
Cell reports, Jan 17, 2013
Individual cancer cells carry a bewildering number of distinct genomic alterations (e.g., copy nu... more Individual cancer cells carry a bewildering number of distinct genomic alterations (e.g., copy number variations and mutations), making it a challenge to uncover genomic-driven mechanisms governing tumorigenesis. Here, we performed exome sequencing on several breast cancer cell lines that represent two subtypes, luminal and basal. We integrated these sequencing data and functional RNAi screening data (for the identification of genes that are essential for cell proliferation and survival) onto a human signaling network. Two subtype-specific networks that potentially represent core-signaling mechanisms underlying tumorigenesis were identified. Within both networks, we found that genes were differentially affected in different cell lines; i.e., in some cell lines a gene was identified through RNAi screening, whereas in others it was genomically altered. Interestingly, we found that highly connected network genes could be used to correctly classify breast tumors into subtypes on the bas...
The Open Bioinformatics Journal, 2010
Human genetic experiments are often conducted based on the orthologous genes in other mammals suc... more Human genetic experiments are often conducted based on the orthologous genes in other mammals such as mouse and rat. The resulting conclusions of such experiments are often limited in their applicability to the human situation. This has raised a question as to why the orthologous genes with closely related or even identical coding regions behave differently in various mammals, and motivated us to study the promoter of these genes. We proposed a functional promoter similarity index (FPSI) based on the number of putative, but statistically significant associations (p 0.05) between transcription factors and their target orthologous genes. We deduced such association through searching known transcription factor binding sites from promoters of the genes. The FPSI was validated using microarray gene expression data. We did pair-wise study of seven vertebrate genomes (human, chimpanzee, mouse, rat, dog, chicken, and zebrafish). The FPSIs of orthologous genes are generally high between human and chimpanzee, with a mean FPSI of 0.79, but gradually decrease when human is compared to the mouse (0.22), rat (0.2), dog (0.2), chicken (0.13) or zebrafish (0.06). We then performed an analogous analysis for 2128 human cancer-associated genes and the results were similar, but had significantly improved FPSIs between these human genes and their orthologs in mouse, rat, and dog. The differences in the promoter regions of orthologous genes appear to be genome wide and negatively correlated with divergence time of the organisms. Such correlation suggests that the FPSI could be used as a measure of phylogenetic conservation.
Oligonucleotides, 2006
Gene silencing is an essential tool in gene discovery and gene therapy. Traditionally, viral deli... more Gene silencing is an essential tool in gene discovery and gene therapy. Traditionally, viral delivery of antisense RNA and, more recently, small interfering RNA (siRNA) molecules in the form of small hairpin RNAs (shRNA) has been used as a strategy to achieve gene silencing. Nevertheless, the enduring challenge is to identify molecules that specifically and optimally silence a given target gene. In this study, we tested a set of adenovirus-delivered antisense RNA fragments and adenovirus-delivered shRNA molecules for their ability to target human transforming growth factor-beta type II receptor (TGFbetaRII). We used a dicistronic reporter, consisting of the coding sequences for TGFbetaRII and green fluorescent protein (GFP) to screen for optimal silencing agents targeting TGFbetaRII. Our results show, for both antisense RNA and shRNA molecules, that their effectiveness in the GFP screen correlated directly with their ability to reduce exogenously expressed TGFbetaRII. Unexpectedly, the antisense RNAs were unable to silence endogenous TGFbetaRII. In contrast, the shRNAs were able to silence endogenous TGFbetaRII. The shRNA that demonstrated the most pronounced effect on the dicistronic TGFbetaRII/GFP reporter reduced endogenous TGFbetaRII protein expression by 70% in A549 cells and reduced TGFbeta signaling by >80% in HeLa cells.
Journal of Tissue Engineering and Regenerative Medicine, 2012
Early embryonic stem cell (ESC) differentiation is marked by the formation of three germ layers f... more Early embryonic stem cell (ESC) differentiation is marked by the formation of three germ layers from which all tissues types arise. Conventionally, ESCs are differentiated by altering their chemical microenvironment. Recently however, it was established that a mechanical microenvironment can also contribute towards cellular phenotype commitment. In this study, we report how the cellular mechanical microenvironment of soft substrates affects the differentiation and phenotypic commitment of ESCs. Mouse ESCs were cultured in a fibrin hydrogel matrix in 2D and 3D cultures. The gelation characteristics of the substrates were modulated by systematically altering the fibrinogen concentration and the fibrinogen-thrombin crosslinking ratio. Analysis of the ESCs cultured on different substrate conditions clearly illustrated the strong influence that substrate physical characteristics assert on cellular behaviours. Specifically, it was found that ESCs had a higher proliferation rate in gels of lower stiffness. Early differentiation events were studied by analyzing the gene and protein expression levels of early germ layer markers. Our results revealed that lower substrate stiffness elicited stronger upregulation of endoderm related genes Sox17, Afp and Hnf4 compared to stiffer substrates. While both 2D and 3D cultures showed a similar response, the effects were much stronger in 3D culture. These results suggest that physical cues can be used to modulate ESC differentiation into clinically relevant tissues such as liver and pancreas. Figure 3. Representative images of cells plated on gels of identical fibrinogen concentration while various crosslinking F/T ratios: 0.25x (left) and 2x (right). Cells attach but do not spread out, forming cell clusters instead. Cell cluster size greater in gels with lower crosslinking ratios M. Jaramillo et al.
Critical Reviews™ in Biomedical Engineering, 2011
Type 1 diabetes affects more than a million people in the United States and many more across the ... more Type 1 diabetes affects more than a million people in the United States and many more across the world. While pharmaceutical interventions and insulin supplementation are the most commonplace treatment of diabetes, these are not essentially cures and can potentially lead to long-term complications. Transplantation of insulin-producing Islets of Langerhans from donor pancreas has been established as a promising alternative to diabetes therapy. While successful islet transplantation has the potential of providing a cure, the primary hurdles to be overcome for it to be clinically viable are the scarcity of donor islets and immune rejection of transplanted islets. Recent advances in stem cell culture and differentiation techniques have established stem cells as a likely source of transplantable islets. Different stem cell sources have been induced toward pancreatic differentiation using specific chemical perturbations along with use of specific substrates. An approach to overcoming the second hurdle of immune rejection of transplantable islets is to encapsulate the islets in specific biomaterials. In this review, we discuss the extensive use of various substrates for pancreatic differentiation of different stem cell sources, along with different biomaterial designs used for islet transplantation.
Uploads
Papers by MARIA ISABEL ELJURI JARAMILLO