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Permanent URI for this collectionhttps://hdl.handle.net/11285/345284
Artículo científico o editorial en una publicación periódica académica sujeto a revisión de pares. Cumple con los índices internacionales o bases de datos de amplia cobertura, como el listado del Current Contents, ISI WEB of Knowledge (http://isiknowledge.com/) e índice de revistas mexicanas de CONACYT (www.conacyt.mx/dac/revistas). Éstos indizan y resumen los artículos de revistas seleccionadas, en todas las áreas del saber.
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- Insulin-like growth factor-1 deficiency and metabolic syndrome(Open Access Publisher, 06/01/2016) Aguirre, G. A.; Rodríguez de Ita, Julieta; De la Garza, R. G.; Castilla Cortázar, Isabel; Tecnologico de Monterrey
- A computer simulation model of Wolbachia invasion for disease vector population modification(Open Access Publisher, 05/10/2015) Guevara Souza, Mauricio; Vallejo Clemente, Edgar E.; Tecnologico de MonterreyAbstract Background Wolbachia invasion has been proved to be a promising alternative for controlling vector-borne diseases, particularly Dengue fever. Creating computer models that can provide insight into how vector population modification can be achieved under different conditions would be most valuable for assessing the efficacy of control strategies for this disease. Methods In this paper, we present a computer model that simulates the behavior of native mosquito populations after the introduction of mosquitoes infected with the Wolbachia bacteria. We studied how different factors such as fecundity, fitness cost of infection, migration rates, number of populations, population size, and number of introduced infected mosquitoes affect the spread of the Wolbachia bacteria among native mosquito populations. Results Two main scenarios of the island model are presented in this paper, with infected mosquitoes introduced into the largest source population and peripheral populations. Overall, the results are promising; Wolbachia infection spreads among native populations and the computer model is capable of reproducing the results obtained by mathematical models and field experiments. Conclusions Computer models can be very useful for gaining insight into how Wolbachia invasion works and are a promising alternative for complementing experimental and mathematical approaches for vector-borne disease control.
- Inferring modules of functionally interacting proteins using the Bond Energy Algorithm(Open Access Publisher, 2008-06-17) Watanabe, Ryosuke L.; Morett, Enrique; Vallejo Clemente, Edgar E.; Tecnologico de MonterreyAbstract Background Non-homology based methods such as phylogenetic profiles are effective for predicting functional relationships between proteins with no considerable sequence or structure similarity. Those methods rely heavily on traditional similarity metrics defined on pairs of phylogenetic patterns. Proteins do not exclusively interact in pairs as the final biological function of a protein in the cellular context is often hold by a group of proteins. In order to accurately infer modules of functionally interacting proteins, the consideration of not only direct but also indirect relationships is required. In this paper, we used the Bond Energy Algorithm (BEA) to predict functionally related groups of proteins. With BEA we create clusters of phylogenetic profiles based on the associations of the surrounding elements of the analyzed data using a metric that considers linked relationships among elements in the data set. Results Using phylogenetic profiles obtained from the Cluster of Orthologous Groups of Proteins (COG) database, we conducted a series of clustering experiments using BEA to predict (upper level) relationships between profiles. We evaluated our results by comparing with COG's functional categories, And even more, with the experimentally determined functional relationships between proteins provided by the DIP and ECOCYC databases. Our results demonstrate that BEA is capable of predicting meaningful modules of functionally related proteins. BEA outperforms traditionally used clustering methods, such as k-means and hierarchical clustering by predicting functional relationships between proteins with higher accuracy. Conclusion This study shows that the linked relationships of phylogenetic profiles obtained by BEA is useful for detecting functional associations between profiles and extending functional modules not found by traditional methods. BEA is capable of detecting relationship among phylogenetic patterns by linking them through a common element shared in a group. Additionally, we discuss how the proposed method may become more powerful if other criteria to classify different levels of protein functional interactions, as gene neighborhood or protein fusion information, is provided.
- Screening family planning needs: an operations research project in Guatemala(Open Access Publisher, 06/05/2004) Mendez, Francisco; López, Felipe; Brambila Paz, Carlos; Burkhart, Marianne; Tecnologico de MonterreyAbstract Background Public sector health care providers in rural Guatemala have infrequently offered family planning information and services in routine visits. This operations research project tested a strategy to modify certain practices that prevent health workers from proactively screening clients' needs and meeting them. Methods The research design was quasi-experimental with a pretest-posttest-follow-up comparison group design. Health districts, which comprise health centers and posts, were purposively assigned to intervention or comparison groups to assure comparability of the two groups. The strategy was based on a job-aid designed to guide health workers in screening clients' reproductive intentions and family planning needs, help them to offer contraceptive methods if the woman expressed interest, and facilitate the provision of the method chosen at the time of the visit. The strategy was implemented at intervention sites during a period of six months. Upon completion of post-intervention measurements, the strategy was scaled up to the comparison sites, and a follow-up assessment was conducted nine months later. Results were evaluated by conducting three rounds of exit interviews with women exposed to the risk of unwanted pregnancy. Results Study results showed a two to five-fold increase in providers' screening of clients' reproductive intentions. The proportion of clients who received information about contraceptives increased from 8% at the baseline to 42% immediately post-intervention, and 36% at the follow-up survey. The intervention also proved successful in improving the role service providers play in offering women a chance to ask questions and assisting women in making a selection. The proportion of women who received a method, referral or appointment increased and remained high in the intervention group, although no change was seen in the comparison group after their participation in the strategy. Conclusion The easy-to-use job aid developed for this project proved useful for screening clients' needs and reducing providers' reluctance to discuss family planning with clients and offer contraceptive services. Such family planning screening devices can be useful in traditional settings where both providers and clients shy away from discussing family planning issues.
- Modelling gene expression profiles related to prostate tumor progression using binary states(Open Access Publisher, 31/05/2013) Martinez, Emmanuel; Trevino, VictorAbstract Background Cancer is a complex disease commonly characterized by the disrupted activity of several cancer-related genes such as oncogenes and tumor-suppressor genes. Previous studies suggest that the process of tumor progression to malignancy is dynamic and can be traced by changes in gene expression. Despite the enormous efforts made for differential expression detection and biomarker discovery, few methods have been designed to model the gene expression level to tumor stage during malignancy progression. Such models could help us understand the dynamics and simplify or reveal the complexity of tumor progression. Methods We have modeled an on-off state of gene activation per sample then per stage to select gene expression profiles associated to tumor progression. The selection is guided by statistical significance of profiles based on random permutated datasets. Results We show that our method identifies expected profiles corresponding to oncogenes and tumor suppressor genes in a prostate tumor progression dataset. Comparisons with other methods support our findings and indicate that a considerable proportion of significant profiles is not found by other statistical tests commonly used to detect differential expression between tumor stages nor found by other tailored methods. Ontology and pathway analysis concurred with these findings. Conclusions Results suggest that our methodology may be a valuable tool to study tumor malignancy progression, which might reveal novel cancer therapies.
- Comparative genomics of bacterial and plant folate synthesis and salvage: predictions and validations(Open Access Publisher, 23/07/2007) de Crécy Lagard, Valérie; El Yacoubi, Basma; de la Garza, Rocío D; Noiriel, Alexandre; Hanson, Andrew D; Tecnologico de MonterreyAbstract Background Folate synthesis and salvage pathways are relatively well known from classical biochemistry and genetics but they have not been subjected to comparative genomic analysis. The availability of genome sequences from hundreds of diverse bacteria, and from Arabidopsis thaliana, enabled such an analysis using the SEED database and its tools. This study reports the results of the analysis and integrates them with new and existing experimental data. Results Based on sequence similarity and the clustering, fusion, and phylogenetic distribution of genes, several functional predictions emerged from this analysis. For bacteria, these included the existence of novel GTP cyclohydrolase I and folylpolyglutamate synthase gene families, and of a trifunctional p-aminobenzoate synthesis gene. For plants and bacteria, the predictions comprised the identities of a 'missing' folate synthesis gene (folQ) and of a folate transporter, and the absence from plants of a folate salvage enzyme. Genetic and biochemical tests bore out these predictions. Conclusion For bacteria, these results demonstrate that much can be learnt from comparative genomics, even for well-explored primary metabolic pathways. For plants, the findings particularly illustrate the potential for rapid functional assignment of unknown genes that have prokaryotic homologs, by analyzing which genes are associated with the latter. More generally, our data indicate how combined genomic analysis of both plants and prokaryotes can be more powerful than isolated examination of either group alone.
- Effects of bone marrow cell transplant on thyroid function in an I131-induced low T4 and elevated TSH rat model(Open Access Publisher, 18/01/2007) Guajardo Salinas, Gustavo E.; Carvajal, Juan A.; Gaytan Ramos, Ángel A.; Arroyo, Luis; López Reyes, Alberto G.; Islas, José F.; Cano, Beiman G.; Arroyo Currás, Netzahualcoyótl; Dávalos, Alfredo; Madrid, Gloria; Moreno Cuevas, Jorge E.; Tecnologico de MonterreyAbstract Background We developed a study using low dose radioactive iodine creating an animal model of transient elevation of thyroid stimulating hormone (TSH). Male derived bone marrow cells were transplanted to asses their effect on thyroid function and their capability to repair the thyroid parenchyma. Results At 40 an 80 days after I131 treatment, the study groups TSH and T4 serum values both increased and decreased significantly respectively compared to the negative control group. Eight weeks after cell transplantation, neither TSH nor T4 showed a significant difference in any group. The mean number of SRY gene copies found in group I (Left Intracardiac Transplant) was 523.3 and those in group II (Intrathyroid Transplant) were only 73. Group III (No Transplant) and IV had no copies. Group I presented a partial restore of the histological pattern of rat thyroid with approximately 20% – 30% of normal-sized follicles. Group II did not show any histological differences compared to group III (Positive control). Conclusion Both a significant increase of TSH and decrease of T4 can be induced as early as day 40 after a low dose of I131 in rats. Restore of normal thyroid function can be spontaneously achieved after using a low dose RAI in a rat model. The use of BM derived cells did not affect the re-establishment of thyroid function and might help restore the normal architecture after treatment with RAI.
- Integration and comparison of different genomic data for outcome prediction in cancer(Open Access Publisher, 29/10/2005) Gomez Rueda, Hugo; Martínez Ledesma, Emmanuel; Martínez Torteya, Antonio; Palacios Corona, Rebeca; Treviño, Victor; Tecnologico de MonterreyIn cancer, large-scale technologies such as next-generation sequencing and microarrays have produced a wide number of genomic features such as DNA copy number alterations (CNA), mRNA expression (EXPR), microRNA expression (MIRNA), and DNA somatic mutations (MUT), among others. Several analyses of a specific type of these genomic data have generated many prognostic biomarkers in cancer. However, it is uncertain which of these data is more powerful and whether the best data-type is cancer-type dependent. Therefore, our purpose is to characterize the prognostic power of models obtained from different genomic data types, cancer types, and algorithms. For this, we compared the prognostic power using the concordance and prognostic index of models obtained from EXPR, MIRNA, CNA, MUT data and their integration for ovarian serous cystadenocarcinoma (OV), multiform glioblastoma (GBM), lung adenocarcinoma (LUAD), and breast cancer (BRCA) datasets from The Cancer Genome Atlas repository. We used three different algorithms for prognostic model selection based on constrained particle swarm optimization (CPSO), network feature selection (NFS), and least absolute shrinkage and selection operator (LASSO).
- Metabolism of 4-chloro-2-nitrophenol in a Gram-positive bacterium, Exiguobacterium sp. PMA(Open Access Publisher, 21/11/2012) Arora, Pankaj K.; Sharma, Ashutosh; Mehta, Richa; Shenoy, Belle D.; Srivastava, Alok; Singh, Vijay P.; Tecnologico de MonterreyAbstract Background Chloronitrophenols (CNPs) are widely used in the synthesis of dyes, drugs and pesticides, and constitute a major group of environmental pollutants. 4-Chloro-2-nitrophenol (4C2NP) is an isomer of CNPs that has been detected in various industrial effluents. A number of physicochemical methods have been used for treatment of wastewater containing 4C2NP. These methods are not as effective as microbial degradation, however. Results A 4C2NP-degrading bacterium, Exiguobacterium sp. PMA, which uses 4C2NP as the sole carbon and energy source was isolated from a chemically-contaminated site in India. Exiguobacterium sp. PMA degraded 4C2NP with the release of stoichiometeric amounts of chloride and ammonium ions. The effects of different substrate concentrations and various inoculum sizes on degradation of 4C2NP were investigated. Exiguobacterium sp. PMA degraded 4C2NP up to a concentration of 0.6 mM. High performance liquid chromatography and gas chromatography–mass spectrometry identified 4-chloro-2-aminophenol (4C2AP) and 2-aminophenol (2AP) as possible metabolites of the 4C2NP degradation pathway. The crude extract of 4C2NP-induced PMA cells contained enzymatic activity for 4C2NP reductase and 4C2AP dehalogenase, suggesting the involvement of these enzymes in the degradation of 4C2NP. Microcosm studies using sterile and non-sterile soils spiked with 4C2NP were carried out to monitor the bioremediation potential of Exiguobacterium sp. PMA. The bioremediation of 4C2NP by Exiguobacterium sp. PMA was faster in non-sterilized soil than sterilized soil. Conclusions Our studies indicate that Exiguobacterium sp. PMA may be useful for the bioremediation of 4C2NP-contaminated sites. This is the first report of (i) the formation of 2AP in the 4C2NP degradation pathway by any bacterium and (iii) the bioremediation of 4C2NP by any bacterium.