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    • Chemical and Biological Activity of Leaf Extracts of Chromolaena leivensis 

      Torrenegra G., Ruben D.; Rodríguez A., Oscar E. (2011)
      The flavonoids 3,5-dihydroxy-7-methoxy-flavanone, 3,5-dihydroxy-7-methoxyflavone and 3,5,7-trihydroxy-6-methoxyflavone were isolated from the leaves of C. leivensis. Preliminary observations in K562 cells (human erythroleukemia) ...
    • Effect of age and coasting period on oocytes quality and their in vitro development from prepubertal cattle 

      Bernal U., Sandra; Gonella D, Ángela; Valbuena, Diego; Mendoza, Rubén; Molina, Juan; Chacón J, Liliana (2011-05)
      Objetivo. Este estudio evaluó el efecto de la edad y el período de aspiración folicular so-bre la calidad del oocito y su posterior desarrollo in vitro con donadoras prepúberes Bos indicus mestizas. Materiales y métodos. ...
    • Semen quality and reproductive performance after artificial insemination with boar sperm stored in a gelatin-supplemented extender 

      Corcini, C.D.; Moreira, F.; Pigozzo, R.; Varela Jr., A.S.; Torres, N.U.; Jr., T. Lucia (2011-06)
      This study tested the effects of inclusion of gelatin in an extender for cooled boar semen on sperm quality during storage and reproductive performance after artificial insemination (AI). In Experiment 1, ejaculates from ...
    • Effects of Ethanol on Food Consumption and Skin Temperature in the Egyptian Fruit Bat (Rousettus aegyptiacus) 

      Korine, Carmi; Sánchez, Francisco; Pinshow, Berry (2011-09)
      Since mammalian frugivores generally choose to eat ripe fruit in which ethanol concentration ([EtOH]) increases as the fruit ripens, we asked whether ethanol acts as an appetitive stimulant in the Egyptian fruit bat, ...
    • Respuesta superovulatoria en número y calidad embrionaria de vacas y novillas Gyr lechero en clima cálido húmedo 

      Motta Delgado, Pablo Andrés; Ramirez Yasnó, Nelly Margarita; Ramos Cuellar, Natalia; Valencia Hernández, Andrés Felipe; Perdomo Tovar, Wilfredo (2011-10)
      Was evaluated a response for quantity and quality of embryos in cows and heifers of dairy Gyr cattle. Were done two treatments with individuals distributed completely at random where heifers (T1, n = 8) and cows (T2, n = ...
    • Comentarios y felicitaciones recibidas tras la obtención por REDVET del certificado y sello de calidad de excelente otorgado por la Fundación Española para la Ciencia y Tecnología (FECYT) dentro del proyecto Apoyo a la profesionalización de revistas científicas españolas (ARCE) y de I3C Índice Iberoamericano de Investigación, así como la indexación en el Repositorio Español de Ciencia y Tecnología (RECYT) 

      Gomez, Jairo E. (2011-12)
    • Multiscale patterns of habitat and space use by the pacarana Dinomys branickii: factors limiting its distribution and abundance 

      Saavedra Rodríguez, Carlos A.; Kattan, Gustavo H.; Osbahr, Karin; Hoyos, Juan Guillermo (2012)
      The factors that influence habitat and space use by animals, and therefore their distribution and abundance, vary with spatial scale. The pacarana Dinomys branickii is a large rodent of the tropical Andes threatened by ...
    • Modelo molecular teórico del receptor serotoninérgico 5HT2A acoplado a proteína G 

      Malagón Bernal, Rafael Eduardo; Fernández Navas, Manuel Alejandro; Acevedo Sarmiento, Orlando Emilio (2012)
      Theoretical molecular model of the G protein-coupled 5HT2A serotonergic receptor. Objective Build a theoretical molecular model of the tertiary structure of the Homo sapiens 5HT2A receptor from experimentally obtained ...
    • Variaciones de la arteria del nodo sinoatrial en población colombiana 

      Quijano Blanco, Yobany; Luque Bernal, Ricardo; Escobar Gutiérrez, Diana; Caro Henao, Luis E. (2012)
      Background. Accurate knowledge regarding the cardiac conduction system’s anatomical-physiological integration is essential for understanding the pathophysiology, diagnosis and management of many complications regarding ...
    • Soil penetration resistance analysis by multivariate and geostatistical methods 

      Medina, Cecilia; Camacho Tamayo, Jesús H.; Cortés, César A. (2012-01)
      La resistencia a la penetración (RP) es un atributo del suelo que permite identificar zonas con restricciones debido a la compactación, que se traduce en impedancia mecánica para el desarrollo de las raíces y en una menor ...
    • Anti-Neoplastic Activity of Two Flavone Isomers Derived from Gnaphalium elegans and Achyrocline bogotensis 

      Thomas, Christan M.; Wood, Robert C.; Wyatt, Jarrett E.; Pendleton, Morgan H.; Torrenegra, Ruben D.; Rodriguez, Oscar E.; Harirforoosh, Sam (2012-06)
      Over 4000 flavonoids have been identified so far and among these, many are known to have antitumor activities. The basis of the relationships between chemical structures, type and position of substituent groups and the ...
    • Ecosystem services research in Latin America: The state of the art 

      Balvanera, Patricia; Uriarte, María; Almeida Leñero, Lucía; Altesor, Alice; DeClerck, Fabrice; Gardner, Toby; Hall, Jefferson (2012-12)
      Ecosystem services science has developed at a fast rate in Latin America, a region characterized by a high biological and cultural diversity, strong emphasis in foreign investment, and high socioeconomic inequities. Here ...
    • Epidemiología 

      Páez Rodríguez, Óscar Enrique; Peñaloza, Fernando (2012-12)
    • Structural features of the two-component system LisR/LisK suggests multiple responses for the adaptation and survival of Listeria monocytogenes 

      Arenas, Nelson E.; Gutiérrez, Andrés; Sánchez Gómez, Myriam; Salazar, Luz Mary; Reyes Montaño1, Edgar (2013)
      Here, we characterized the structure of the two-component regulatory system, LisR/LisK, in Listeria monocytogenes. To predict the structure of both proteins and the relationship between them, we employed several bioinformatic ...
    • Interaction of Bordetella bronchiseptica and Its Lipopolysaccharide with In Vitro Culture of Respiratory Nasal Epithelium 

      Gallego, Carolina; Middleton, Andrew M.; Martínez, Nhora; Romero, Stefany; Iregui, Carlos (2013)
      The nasal septa of fetal rabbits at 26 days of gestation were harvested by cesarean section of the does while under anesthesia and then exposed to Bordetella bronchiseptica or its lipopolysaccharide (LPS) for periods of 2 ...
    • Ultrastructural Comparison of the Nasal Epithelia of Healthy and Naturally Affected Rabbits with Pasteurella multocida A 

      Esquinas, Paula; Botero, Lucía; Patiño, María del Pilar; Gallego, Carolina; Iregu, Carlos (2013)
      An ultrastructural comparison between the nasal cavities of healthy rabbits and those suffering from two forms of spontaneous infection with Pasteurella multocida was undertaken. Twelve commercially produced rabbits of ...
    • Stomatal behavior in fruits and leaves of the purple passion fruit (Passiflora edulis Sims) and fruits and cladodes of the yellow pitaya [Hylocereus megalanthus (K. Schum. ex Vaupel) Ralf Bauer] 

      Sánchez, Camilo; Fischer, Gerhard; Sanjuanelo Corredor, Danny Wilson (2013)
      Las plantas C3 y CAM reaccionan fotosintéticamente diferentes, sin embargo, ambas pueden crecer en la misma zona agroecológica en los trópicos. Por esta razón se evaluó el comportamiento de estomas en frutos y hojas de ...
    • Cuantificación de hidrocarburos policíclicos aromáticos urinarios en policías de tránsito del área metropolitana de Bogotá 

      Díaz Merchán, Cristian C.; Y. Rojas, Néstor; Rodríguez Pulido, Alba I.; Prieto Suarez, Edgar; Urrego Novoa, José Ricardo (2013)
      Objetivos: Cuantificar niveles urinarios de 1-hidroxipireno (1-OHP) y 3-hidroxibenzo [a] pireno (3-BAP) metabolitos de hidrocarburos policíclicos aromáticos (HAP) de interés toxicológico y relacionar su detección con el ...
    • Microbiological conditions for culturing Helicobacter Pylori 

      Bayona Rojas, Martín Alonso (2013-01)
      Early diagnosis and culturing of Helicobacter pylori are of great importance for the study of the growth characteristics of these bacteria which can contribute to knowledge of classical and molecular epidemiology, ...
    • Effects of different oocyte retrieval and in vitro maturation systems on bovine embryo development and quality 

      Bernal Ulloa, Sandra Milena; Heinzmann, Julia; Herrmann, Doris; Timmermann, Bernd; Baulain, Ulrich; Großfeld, Rudolf; Diederich, Mike (2013-04)
      Cyclic adenosine monophosphate (cAMP) modulators have been used to avoid spontaneous oocyte maturation and concomitantly improve oocyte developmental competence. The current work evaluated the effects of the addition of ...

      Envíos recientes

      • Chemical and Biological Activity of Leaf Extracts of Chromolaena leivensis

        ...

        Torrenegra G., Ruben D. | 2011

        The flavonoids 3,5-dihydroxy-7-methoxy-flavanone, 3,5-dihydroxy-7-methoxyflavone and 3,5,7-trihydroxy-6-methoxyflavone were isolated from the leaves of C. leivensis. Preliminary observations in K562 cells (human erythroleukemia) using the trypan blue test, showed a 90% viability at a concentration of 100 µg/mL; however, further testing of the flavonoids at concentrations of 25, 50 and 100 µg/mL showed toxicity affecting the morphology of human erythroleukemia cells (K562) and human melanoma cells (A375). Induction of apoptosis was produced by 3.5-dihydroxy-7-methoxyflavone at 72 hours after treatment with arrest in the G2 / M phase of the cell cycle. The A375 cells treated with 50 µg/mL of 3.5-dihydroxy-7-methoxy-flavanone for 24, 48 and 72 hours, display effects on the behavior of the cell cycle. The flavonoid 3,5-dihydroxy-7-methoxyflavone has activity on the mitochondrial membrane at concentrations of 25, 50 and 100 µg/mL, at time intervals of 8 to 12 hours. The flavonoids 3,5-dihydroxy-7-methoxy-flavanone and 3,5-dihydroxy-7-methoxyflavone at a concentration of 25 µg/mL increased the expression of costimulatory molecules corresponding to the phenotype presented by mature dendritic cells with differentiation markers CD40, CD83, CD86 and HLA-DR. The two flavonoids at concentrations between 0.39 and 100 µg/mL slightly increased the proliferation of peripheral blood mononuclear cells in the presence and in the absence of phytohemagglutinin. These flavonoids at concentrations of 50 and 100 µg/mL slightly increased the proliferation of fibroblasts.

        LEER

      • Effect of age and coasting period on oocytes quality and their in vitro development from prepubertal cattle

        ...

        Bernal U., Sandra | 2011-05

        Objetivo. Este estudio evaluó el efecto de la edad y el período de aspiración folicular so-bre la calidad del oocito y su posterior desarrollo in vitro con donadoras prepúberes Bos indicus mestizas. Materiales y métodos. Las hembras donantes recibieron un implante de norgestomet y benzoato de estradiol y cuatro días más tarde una dosis única de 150 UI de eCG. Las aspiración folicular se realizó en tres tiempos (24, 48, y h 56) y en cuatro edades (3, 6,10, y 12 meses). Todos los folículos antrales fueron aspirados y se realizaron procedimientos de maduración, fertilización y cultivo in vitro. Resultados. Se aspiraron 439 folículos en total, de los cuales 385 (87.7%) fueron de 2-5 mm, 41 (9.33%) fueron de 5-10 mm, y fueron 13 (2.3%) > 10 mm. Se recuperó un total de 373 oocitos (84.9%) y se encontraron diferencias significativas (p<0.05) entre los promedios de los animales de 6 (9.3) y 10 meses (32.3). 285 (76.4%) oocitos fueron sometidos a los procesos in vitro. La tasa de división fue significativamente mayor (p<0.05) en los animales de 10 (27.1%) y 12 meses (26.8%). Aunque el número de embriones transferibles fue bajo, existieron di-ferencias entre las edades (p<0.05), obteniendo el porcentaje más alto los animales de 10 meses (12.6%). Conclusiones. Un período de aspiración superior a 24 h tiene un efecto negativo sobre la calidad del oocito. Algunos oocitos procedentes de terneras de 3 meses fueron competentes en el desarrollo in vitro, sin embargo, un mayor número de embriones se produjeron con hembras de 10 y 12 meses de edad.

        LEER

      • Semen quality and reproductive performance after artificial insemination with boar sperm stored in a gelatin-supplemented extender

        ...

        Corcini, C.D. | 2011-06

        This study tested the effects of inclusion of gelatin in an extender for cooled boar semen on sperm quality during storage and reproductive performance after artificial insemination (AI). In Experiment 1, ejaculates from four boars were stored in Beltsville Thawing Solution (BTS) and BTS including 1.5% and 3.0% gelatin. Sperm motility and morphology were similar among extenders during 72 h of storage (PN0.05). In Experiment 2, ejaculates from four boars were stored in BTS and BTS including 1.5% gelatin. Motility, normal morphology and membrane integrity declined over storage time for both extenders (Pb0.05). Decrease on normal sperm morphology over time was less severe in semen stored in gelatin-supplemented BTS (Pb0.05). In Experiment 3, AI was conducted in sows from a commercial farm using semen stored in BTS with or without 1.5% gelatin. Farrowing rate and total litter size did not differ (Pb0.05), but AI with gelatin-supplemented BTS was shorter and presented less semen backflow (Pb0.05). Semen stored in BTS including gelatin presented acceptable quality for longer periods and was efficiently used in AI with no losses in reproductive performance.

        LEER

      • Effects of Ethanol on Food Consumption and Skin Temperature in the Egyptian Fruit Bat (Rousettus aegyptiacus)

        ...

        Korine, Carmi | 2011-09

        Since mammalian frugivores generally choose to eat ripe fruit in which ethanol concentration ([EtOH]) increases as the fruit ripens, we asked whether ethanol acts as an appetitive stimulant in the Egyptian fruit bat, Rousettus aegyptiacus, and also studied the effects of ethanol on their skin temperature (Ts). We hypothesized that the responses of fruit bats to dietary ethanol are concentration dependent and tested the predictions that the bats’ response is positive, i.e., they eat more when [EtOH] in the food is in the range found in naturally ripe fruit, while it negatively affects them at higher concentrations. We also tested the prediction that in winter, even when availability of fruit is low and thermoregulatory costs are high, ingestion of ethanol by fruit bats is low because assimilated ethanol reduces shivering thermogenesis and peripheral vasodilation; these, alone or together, are detrimental to the maintenance of body temperature (Tb). In summer, captive bats offered food containing 0.1% ethanol significantly increased consumption over food with no ethanol; they did not change consumption when food contained 0.01, 0.3, or 0.5% ethanol; but significantly decreased consumption at higher levels of ethanol [EtOH], i.e., 1 and 2%. In winter, captive bats ate significantly less when their food contained 0.1% ethanol than when it contained 0, 0.3, or 0.5%. During summer, freshly caught bats ate significantly more ethanol-containing food than freshly caught bats in winter. Skin temperature (Ts) in Egyptian fruit bats decreased significantly at an ambient temperature (Ta) of 128C (winter conditions) after gavage with liquid food containing 1% ethanol. The effect was clearly temperature-dependent, since ethanol did not have the same effect on bats gavaged with food containing 1% or no ethanol at a Ta of 258C (summer conditions). In conclusion, ethanol may act as an appetitive stimulant for Egyptian fruit bats at low concentrations, but only in summer. Bats are deterred by food containing [EtOH] corresponding to that in overripe, unpalatable fruit (1 and 2%). Furthermore, during winter, Egyptian fruit bats are deterred by ethanol-rich fruit, possibly due to the potential thermoregulatory consequences of ethanol consumption.

        LEER

      • Respuesta superovulatoria en número y calidad embrionaria de vacas y novillas Gyr lechero en clima cálido húmedo

        ...

        Motta Delgado, Pablo Andrés | 2011-10

        Was evaluated a response for quantity and quality of embryos in cows and heifers of dairy Gyr cattle. Were done two treatments with individuals distributed completely at random where heifers (T1, n = 8) and cows (T2, n = 6) were subjected to superovulation protocol (SOV) through of follicular wave synchronization and super-stimulation with 200 mg of p-FSH among the 4 and 7 day of protocol, in the 8 and 9 day was made AI in the afternoon and in the morning respectively. The embryos were collected by nonsurgical method seven days after first insemination and were classified by stereo-microscope. Of T1 and T2 were collected 9.36 ± 6.39 and 9.83 ± 9.04 structures per animal, respectively, of which 1.50 ± 1.69 and 2.67 ± 1.75 respectively were degenerate structures. The heifers smaller than 30 months produced 14.50 ± 4.73 total structures and 12.25 ± 3.95 viable structures for animal compared with the 4.25 ± 1.71 total structures and 3.25 ± 1.29 viable per animal in heifers bigger than 30 months. Regarding the quality of structures, heifers biggest than 30 months produced 3.25 ± 0.96, 0.75 ± 1.50 and 0.25 ± 0.50 structures grade I, II and IV respectively, while heifers smaller than 30 months produced 11.00 ± 2.83, 1.25 ± 1.50 and 2.25 ± 1.71 structures grade I, II and IV respectively. Difference doesn´t exist in the quantity neither in the quality of embryos collected from heifers and cows dairy Gyr cattle, however, among the biggest and smaller heifers to 30 months, the last ones have best response in quantity and embryonic quality.

        LEER

      • Comentarios y felicitaciones recibidas tras la obtención por REDVET del certificado y sello de calidad de excelente otorgado por la Fundación Española para la Ciencia y Tecnología (FECYT) dentro del proyecto Apoyo a la profesionalización de revistas científicas españolas (ARCE) y de I3C Índice Iberoamericano de Investigación, así como la indexación en el Repositorio Español de Ciencia y Tecnología (RECYT)

        ...

        Gomez, Jairo E. | 2011-12

        LEER

      • Multiscale patterns of habitat and space use by the pacarana Dinomys branickii: factors limiting its distribution and abundance

        ...

        Saavedra Rodríguez, Carlos A. | 2012

        The factors that influence habitat and space use by animals, and therefore their distribution and abundance, vary with spatial scale. The pacarana Dinomys branickii is a large rodent of the tropical Andes threatened by illegal hunting and habitat loss. We identified variables related to pacarana habitat use at 4 spatial scales in the Colombian Andes: landscape (3.14 km2 circles), forest patch, foraging area, and den. At the landscape scale, pacaranas used areas with 20 to 95% forest cover that were not different from randomly sampled sites. At the forest fragment scale, used patches (mean = 12 ha) were larger than unused patches, but independent of distance to continuous forest. At the foraging area scale, habitat use was related to the presence of rocky caves used as dens and was unrelated to forest structure. At the den scale, pacaranas used deep caves (>4 m) in sloping rocky outcrops with >40% exposed rock (in 100 m2 patches). Pacarana groups (4 to 5 individuals) had a mean home range of 2.45 ha around caves. We estimated a population density of 9.9 and 5.5 groups km−2 based on sign clusters (footprints, latrines, and foraging areas) and dens, respectively. Pacaranas fed on a variety of plant families found in primary and secondary forest and disturbed areas near streams. Our results indicate that pacaranas can survive in forest fragments, and the main factor limiting their distribution and abundance is the availability of adequate dens. Conservation of pacarana populations in rural landscapes may be helped by protecting a network of forest patches connected by riparian vegetation, but these populations would be vulnerable to illegal hunting.

        LEER

      • Modelo molecular teórico del receptor serotoninérgico 5HT2A acoplado a proteína G

        ...

        Malagón Bernal, Rafael Eduardo | 2012

        Theoretical molecular model of the G protein-coupled 5HT2A serotonergic receptor. Objective Build a theoretical molecular model of the tertiary structure of the Homo sapiens 5HT2A receptor from experimentally obtained structures as templates. Materials and methods In the construction of the theoretical model we considered the protocol established by Ballesteros and Weinstein for the construction of the G-protein coupled receptor, by the alignment of the amino acid sequence, hydrophobicity profiles, refinement of loops by spatial restrictions and energy minimization with the force field OPLS_2005. Results The resulting model was validated by the Ramachandran plot with 91.7% of amino acids within the limits set for angles phi and psi and a RMSD of 0.95 Å with respect to bovine rhodopsin. Conclusions We obtained a validated theoretical model useful in studies of ligand-receptor docking.

        LEER

      • Variaciones de la arteria del nodo sinoatrial en población colombiana

        ...

        Quijano Blanco, Yobany | 2012

        Background. Accurate knowledge regarding the cardiac conduction system’s anatomical-physiological integration is essential for understanding the pathophysiology, diagnosis and management of many complications regarding coronary disease and heart disease in general. One of the more variable fundamental aspects, having the greatest clinical impact, concerns the origin and course of arteries irrigating the sino-atrial node (SAN). Objective. Determining the origin, course and distribution of arteries supplying the SAN in a sample of the Colombian population. Materials and methods. 60 cardiopulmonary and digestive blocks were taken by convenience sampling. Conventional dissection of the genitalia determined gender; the coronary artery was then dissected, specifically the SAN, to establish origin and route. Results. It was found that 75% of the SAN artery’s blood supply came from the right coronary artery (RCA), 15% from the circumflex artery and 10% was co-dominant. 86.6% of courses were linear; 13.4% were Y-shaped or Yand double trident shaped. Conclusions. The prevalence of SAN artery origin in the RCA in this study was consistent with similar research findings, regardless of geographical and racial origin. However, this study report some courses not previously described in the literature, such as Y-, double Y-, inverted K- and trident-shaped forms

        LEER

      • Soil penetration resistance analysis by multivariate and geostatistical methods

        ...

        Medina, Cecilia | 2012-01

        La resistencia a la penetración (RP) es un atributo del suelo que permite identificar zonas con restricciones debido a la compactación, que se traduce en impedancia mecánica para el desarrollo de las raíces y en una menor productividad de los cultivos. El objetivo del presente trabajo fue caracterizar la RP de un suelo agrícola, mediante análisis geoestadístico y multivariado. El muestreo se realizó de manera aleatoria en 90 puntos, hasta una profundidad de 0,60 m. Se determinaron los modelos de distribución espacial de la RP y se delimitaron áreas con problemas de impedancia mecánica de las raíces. La RP presentó distribución aleatoria a 0,55 y 0,60 m de profundidad. La RP en las otras profundidades analizadas mostraron dependencia espacial, con ajustes a modelos exponenciales y esféricos. El análisis jerárquico que consideró puntos de muestreo, permitió establecer zonas con problemas de compactación, identificadas en los mapas obtenidos mediante interpolación por kriging. El análisis de componentes principales permitió identificar tres capas de suelo, donde la capa intermedia fue la que presentó los mayores valores de RP.

        LEER

      • Anti-Neoplastic Activity of Two Flavone Isomers Derived from Gnaphalium elegans and Achyrocline bogotensis

        ...

        Thomas, Christan M. | 2012-06

        Over 4000 flavonoids have been identified so far and among these, many are known to have antitumor activities. The basis of the relationships between chemical structures, type and position of substituent groups and the effects these compounds exert specifically on cancer cells are not completely elucidated. Here we report the differential cytotoxic effects of two flavone isomers on human cancer cells from breast (MCF7, SK-BR-3), colon (Caco-2, HCT116), pancreas (MIA PaCa, Panc 28), and prostate (PC3, LNCaP) that vary in differentiation status and tumorigenic potential. These flavones are derived from plants of the family Asteraceae, genera Gnaphalium and Achyrocline reputed to have anti-cancer properties. Our studies indicate that 5,7-dihydroxy-3,6,8-trimethoxy-2-phenyl-4H-chromen-4-one (5,7-dihydroxy-3,6,8-trimethoxy flavone) displays potent activity against more differentiated carcinomas of the colon (Caco-2), and pancreas (Panc28), whereas 3,5-dihydroxy6,7,8-trimethoxy-2-phenyl-4H-chromen-4-one (3,5-dihydroxy-6,7,8-trimethoxy flavone) cytototoxic action is observed on poorly differentiated carcinomas of the colon (HCT116), pancreas (Mia PaCa), and breast (SK-BR3). Both flavones induced cell death (.50%) as proven by MTT cell viability assay in these cancer cell lines, all of which are regarded as highly tumorigenic. At the concentrations studied (5–80 mM), neither flavone demonstrated activity against the less tumorigenic cell lines, breast cancer MCF-7 cells, androgen-responsive LNCaP human prostate cancer line, and androgen-unresponsive PC3 prostate cancer cells. 5,7-dihydroxy-3,6,8-trimethoxy-2-phenyl-4H-chromen-4-one (5,7-dihydroxy-3,6,8-trimethoxy flavone) displays activity against more differentiated carcinomas of the colon and pancreas, but minimal cytotoxicity on poorly differentiated carcinomas of these organs. On the contrary, 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-chromen-4-one (3,5-dihydroxy-6,7,8-trimethoxy flavone) is highly cytotoxic to poorly differentiated carcinomas of the colon, pancreas, and breast with minimal activity against more differentiated carcinomas of the same organs. These differential effects suggest activation of distinct apoptotic pathways. In conclusion, the specific chemical properties of these two flavone isomers dictate mechanistic properties which may be relevant when evaluating biological responses to flavones.

        LEER

      • Ecosystem services research in Latin America: The state of the art

        ...

        Balvanera, Patricia | 2012-12

        Ecosystem services science has developed at a fast rate in Latin America, a region characterized by a high biological and cultural diversity, strong emphasis in foreign investment, and high socioeconomic inequities. Here we conducted the following analyses at the regional and national scales: (1) how and when did the study of ecosystem services arise in each country?, (2) what is our present understanding of ecosystem service supply, delivery to societies, and social and economic values?, (3) what is the state of the art in integrating tradeoffs among services and in using interdisciplinary perspectives?, and (4) how has ecosystem service research been connected to policy design or management for sustainability? A large literature review (41000 references) showed that in Latin America ES supply and links to policy have been the most frequently assessed. Overall, emphasis has been placed on a few services, namely carbon and water. Payments for ecosystem services have received considerable attention in the region, though with strong differences across nations and with important limitations in their application. The future of the ecosystem service paradigm in Latin America will largely depend on its capacity to demonstrate effectiveness in meeting both conservation and development goals.

        LEER

      • Epidemiología

        ...

        Páez Rodríguez, Óscar Enrique | 2012-12

        LEER

      • Structural features of the two-component system LisR/LisK suggests multiple responses for the adaptation and survival of Listeria monocytogenes

        ...

        Arenas, Nelson E. | 2013

        Here, we characterized the structure of the two-component regulatory system, LisR/LisK, in Listeria monocytogenes. To predict the structure of both proteins and the relationship between them, we employed several bioinformatic tools and databases. Based on our results, LisK protein is embedded in the cell membrane and its modular composition (HAMP, histidine kinase and ATPase domains) is associated with its autophosphorylation (His-266). A stimulus-response likely determines the sequential signal propagation from the bacterial cell surface to its cytoplasmic components. According to our results, LisR is a cytoplasmic protein with a receptor domain (homologous to CheY) that comprises a phosphoacceptor residue (Asp-52) and a DNA-binding domain, which may allow the transmission of a specific transcriptional response. LisR/LisK has been experimentally characterized both biochemically and functionally in other Bacilli pathophysiology; our structure-function approach may facilitate the design of suitable inhibitors.

        LEER

      • Interaction of Bordetella bronchiseptica and Its Lipopolysaccharide with In Vitro Culture of Respiratory Nasal Epithelium

        ...

        Gallego, Carolina | 2013

        The nasal septa of fetal rabbits at 26 days of gestation were harvested by cesarean section of the does while under anesthesia and then exposed to Bordetella bronchiseptica or its lipopolysaccharide (LPS) for periods of 2 and 4 hours. A total of 240 explants were used. The tissues were examined using the Hematoxylin & Eosin technique. Then, semithin sections (0.5 m) were stained with toluidine blue and examined with indirect immunoperoxidase (IPI) and lectin histochemistry. The most frequent and statistically significant findings were as follows: (1) cell death and increased goblet cell activity when exposed to bacteria and (2) cell death, cytoplasmic vacuolation and infiltration of polymorphonuclear leukocytes when exposed to LPS. The lesions induced by the bacterium were more severe than with LPS alone, except for the cytoplasmic vacuolation in epithelial cells. IPI stained the ciliated border of the epithelium with the bacterium more intensely, while LPS lectin histochemistry preferentially labeled the cytoplasm of goblet cell. These data indicate that B. bronchiseptica and its LPS may have an affinity for specific glycoproteins that would act as adhesion receptors in both locations.

        LEER

      • Ultrastructural Comparison of the Nasal Epithelia of Healthy and Naturally Affected Rabbits with Pasteurella multocida A

        ...

        Esquinas, Paula | 2013

        An ultrastructural comparison between the nasal cavities of healthy rabbits and those suffering from two forms of spontaneous infection with Pasteurella multocida was undertaken. Twelve commercially produced rabbits of different ages and respiratory health status were divided into four groups: healthy from 0 to 21 days (G1, ); healthy from 23 to 49 days (G2, ); healthy from 51 to 69 days (G3, ); diseased rabbits with septicemia and the rhinitic form of P. multocida infection (G4, ). The main ultrastructural changes observed were a widening of the interepithelial spaces, increased activity and number of goblet cells, the formation of two types of vacuoles in epithelial cells, the degranulation and migration of heterophils between the epithelial cells, and the association of this migration with some of the other changes. No bacteria were observed adhering to the epithelium, and very few were observed free in the mucus. Scant inter-epithelial spaces were found in healthy rabbits, but they were not as large and numerous as those found in diseased animals. We discuss the origin and meaning of these changes but, we focus on the significance of the inter-epithelial spaces and goblet cells for the defense of the upper respiratory airways against the bacterium and its lipopolysaccharide.

        LEER

      • Stomatal behavior in fruits and leaves of the purple passion fruit (Passiflora edulis Sims) and fruits and cladodes of the yellow pitaya [Hylocereus megalanthus (K. Schum. ex Vaupel) Ralf Bauer]

        ...

        Sánchez, Camilo | 2013

        Las plantas C3 y CAM reaccionan fotosintéticamente diferentes, sin embargo, ambas pueden crecer en la misma zona agroecológica en los trópicos. Por esta razón se evaluó el comportamiento de estomas en frutos y hojas de gulupa y en frutos y cladodios de pitahaya amarilla bajo condiciones naturales en los municipios de Granada y Fusagasugá, departamento de Cundinamarca (Colombia). Se hicieron improntas sobre la superficie de las hojas, frutos y cladodios. Se realizaron tres lecturas, cada una duró 72 horas, haciendo impresiones cada 3 horas sobre tres muestras diferentes para luego observarlas en microscopio, haciendo un conteo de estomas abiertos y cerrados en cada especie. En cada muestreo se obtuvieron datos de radiación solar, temperatura y humedad relativa (HR). En gulupa se encontró un comportamiento típico de una planta C3 tanto para las hojas como para los frutos, además de encontrar una correlación positiva entre la apertura estomática y la radiación y temperatura, así como una correlación negativa entre la apertura estomática y la HR. En pitahaya se encontró un comportamiento típico de una planta CAM, observando una correlación negativa entre la apertura estomática y la radiación y temperatura, así como una correlación positiva entre apertura estomática y HR. La radiación, la temperatura y la HR afectaron la apertura estomático en frutos y cladodios. Las densidades estomáticas contrastaron altamente entre las especies y los órganos de la planta. En gulupa fueron encontrados 106,53 estomas/mm2 en la superficie de las hojas, pero solo 12,64 estomas/mm2 en la del fruto; mientras que en pitahaya fueron encontrados 11,28 y 1,43 estomas/mm2 en cladodios y frutos, respectivamente.

        LEER

      • Cuantificación de hidrocarburos policíclicos aromáticos urinarios en policías de tránsito del área metropolitana de Bogotá

        ...

        Díaz Merchán, Cristian C. | 2013

        Objetivos: Cuantificar niveles urinarios de 1-hidroxipireno (1-OHP) y 3-hidroxibenzo [a] pireno (3-BAP) metabolitos de hidrocarburos policíclicos aromáticos (HAP) de interés toxicológico y relacionar su detección con el grado de exposición a material particulado de tamaño menor a 10 micras (PM10) u otros factores, en una población de Policías de Tránsito ocupacionalmente expuestos en el área metropolitana de Bogotá D.C. Métodos Se realizó un estudio de corte transversal en 524 Policías de Tránsito de los cuales 413 desarrollaban funciones operativas y 111 administrativas. Se tomaron muestras de orina de todos los individuos incluidos, para la determinación de metabolitos de HAP mediante cromatografía de gases con detección de masas. Se analizó la presencia de factores asociados con la detección de los metabolitos como tabaquismo, consumo de alimentos asados, lugar de residencia y exposición a PM10. Como medida de asociación se calcularon Odds Ratio (OR). Resultados Se encontraron niveles de 1-OHP y 3-BAP superiores en los individuos expuestos con OR significativos para detección de los metabolitos de 6,3 (IC95 3,6-11,1) y 15,6 (IC95 6,2-39), respectivamente. Se hallaron OR significativos para detección de metabolitos de HAP y exposición a PM10, tabaquismo y consumo de alimentos asados. Discusión Existe una asociación importante y significativa entre la exposición laboral a contaminación ambiental y la detección de metabolitos de HAP de importancia toxicológica en muestras de orina. Factores tales como tabaquismo, consumo de alimentos asados recientemente y exposición a PM10 también se encontraron asociados positivamente con la detección de dichos metabolitos pero en menor proporción.

        LEER

      • Microbiological conditions for culturing Helicobacter Pylori

        ...

        Bayona Rojas, Martín Alonso | 2013-01

        Early diagnosis and culturing of Helicobacter pylori are of great importance for the study of the growth characteristics of these bacteria which can contribute to knowledge of classical and molecular epidemiology, genetic diversity and susceptibility to antibiotics. The ubiquity and importance of this pathogen throughout the world has forced us to consider and propose effective routine alternatives for isolating and identifying these bacteria in microbiology laboratories. This review was conducted to describe the literature concerning the conditions for cultivation of this organism in the laboratory.

        LEER

      • Effects of different oocyte retrieval and in vitro maturation systems on bovine embryo development and quality

        ...

        Bernal Ulloa, Sandra Milena | 2013-04

        Cyclic adenosine monophosphate (cAMP) modulators have been used to avoid spontaneous oocyte maturation and concomitantly improve oocyte developmental competence. The current work evaluated the effects of the addition of cAMP modulators forskolin, 3-isobutyl-1-methylxanthine (IBMX) and cilostamide during in vitro maturation on the quality and yields of blastocysts. The following experimental groups were evaluated: (i) slicing or (ii) aspiration and maturation in tissue culture medium (TCM)199 for 24 h (TCM24slicing and TCM24aspiration, respectively), (iii) aspiration and maturation in the presence of cAMP modulators for 30 h (cAMP30aspiration) and in vivo-produced blastocysts. In vitro-matured oocytes were fertilized and presumptive zygotes were cultured in vitro to assess embryo development. Cleavage, blastocyst formation, blastocyst cell number, mRNA abundance of selected genes and global methylation profiles were evaluated. Blastocyst rate/zygotes for the TCM24aspiration protocol was improved (32.2 ± 2.1%) compared with TCM24slicing and cAMP30aspiration (23.4 ± 1.2% and 23.3 ± 2.0%, respectively, P 0.05), while those from the other groups were significantly elevated. It is concluded that retrieval, collection systems and addition of cAMP modulators can affect oocyte developmental competence, which is reflected not only in blastocyst rates but also in global DNA methylation and gene expression patterns.

        LEER

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      Universidad de Ciencias Aplicadas y Ambientales U.D.C.A © 2019 - 2021

      NIT 860.403.721-2

      Resolución del Ministerio de Educación Nacional 7392 del 20 de mayo de 1983 - Código SNIES 1835 Acreditación Institucional de Alta Calidad: Resolución 017390 del 27 de diciembre de 2019 (4 años), otorgada por el Ministerio de Educación Nacional Institución de Educación Superior sujeta a la inspección y vigilancia del Ministerio de Educación Nacional

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