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Imagen de apoyo de  Approximal caries: Prevalence and progression rate in Young Danish adults and an innovative non-operative approach for lesions around the EDJ

Approximal caries: Prevalence and progression rate in Young Danish adults and an innovative non-operative approach for lesions around the EDJ

Por: Stefania Martignon | Fecha: 01/01/2005

A literature review disclosed that even under very strict caries preventive control, in young Swedish people many initial approximal lesions slowly progress. A study was performed to investigate if the same trend could be seen in young Danish adults. In 1996 a group of Danish military conscripts were investigated clinically and radiographically. Based on the radiographs, one lesion with radiolucency up to one third in the dentine was randomly selected from each conscript.Contact was established with these former conscripts in 2002 and radiographs taken around 2002 were used to investigate the state of the selected lesions in terms of regression, stabilization or progression. It was observed that about 60% of the selected lesions had progressed during the 5 to 6 year period. Therefore there was a need to look for other preventive measures than those traditionally used in a Danish context, such as instructions in flossing and local application of fluoride. Looking through the literature, it was realized that sealing of occlusal lesions was highly effective but this procedure was not used on approximal surfaces.The next step was to investigate if it was technically possible to seal approximal lesions and if so what material should be used. A laboratory study was conducted in which 6 dental materials were compared in relation to: their handling, presence at the surface of the lesion, and ability to penetrate into a lesion. Based on that study Gluma One Bond® (Heraeus Kulzer) was selected to be used in further studies. The final step was an 18-month clinical investigation to evaluate the effect of sealing approximal lesions. About 80 young adults from Denmark and Colombia participated in this investigation; each had at least 2 initial approximal lesions.One lesion was selected for sealing; the other one acted as control. Baseline radiographs were taken by means of special equipment so new radiographs could be taken in the same position after 18 months. The sealing procedure was performed in accordance with the guideline designed in the laboratory study. The patient was instructed to floss all sealed and non-sealed approximal lesions. Radiographs were used to assess caries progression in the test and control lesions in three ways: by comparing baseline with final scoring of the lesions on the individual conventional radiographs, by reading the conventional radiographs as pairs and finally using subtraction radiography of digitized images.The examiner was blind to lesion type (test or control) for all comparisons and also blind to whether radiographs were baseline or follow up in the case of examinations of the single radiographs and paired comparison. Repeat assessment of the radiographs was conducted on 20% of the radiographs and the subtraction images. For the paired comparison of radiographs and subtraction radiography assessment significantly more control lesions progressed (47.2%; 85%) than test lesions (22.2%; 43%) (P-values<0.05). For the independent examination of the radiographs a similar pattern was seen but the difference between the two groups was not statistically significant (P=0.06).In conclusion, many approximal lesions seemed to progress on young adults irrespective of the preventive regime they were advised to take. This study has developed and investigated a technique for sealing early approximal lesions which seems to be more effective at preventing lesion progression than conventional interventions such as brushing and flossing. There is a need however, for defining more precisely criteria at selecting lesions to be sealed; for developing better materials in terms of better penetration skill and that they stay there, and for clinical investigations which evaluate the long term effect of sealing the approximal lesions.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Tesis
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Approximal caries: Prevalence and progression rate in Young Danish adults and an innovative non-operative approach for lesions around the EDJ

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Atoxil: observaciones sobre su valor terapéutico en la sífilis

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Imagen de apoyo de  Attitudes towards body size and physical appearance among Colombian and American college students:A Multi-cultural Study = Actitudes hacia el tamaño del cuerpo y apariencia fisica en estudiantes universitarios Colombianos y Americanos: Un Estudio Multi-C

Attitudes towards body size and physical appearance among Colombian and American college students:A Multi-cultural Study = Actitudes hacia el tamaño del cuerpo y apariencia fisica en estudiantes universitarios Colombianos y Americanos: Un Estudio Multi-C

Por: Natalia Rojas Segura | Fecha: 01/01/2009

The current study analyzed attitudes towards size and physical appearance among four hundred and seventy Colombian and two hundred and ten American college students. The effects of gender and culture (and their interaction) on thin ideal internalization, sociocultural pressure to be thin, and body image dissatisfaction were examined in the sample. Results from the study showed that there are differences between gender and country: Colombian students perceived themselves as having a better body image overall compared to American students; females from both countries had a lower body image satisfaction compared to males. Surprisingly, males from both countries worry about their physical size and appearance. Implications for future research include validating instruments especially for a Colombian population, as well as continuing to include males in studies related to body image and eating disorders because it was found that they were also unsatisfied with their overall body image. 
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Tesis
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Attitudes towards body size and physical appearance among Colombian and American college students:A Multi-cultural Study = Actitudes hacia el tamaño del cuerpo y apariencia fisica en estudiantes universitarios Colombianos y Americanos: Un Estudio Multi-C

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Imagen de apoyo de  Auricular reconstruction with a nanocomposite polymer = Reconstrucción auricular con un nanopolimero

Auricular reconstruction with a nanocomposite polymer = Reconstrucción auricular con un nanopolimero

Por: Carlos Enrique Ramírez Blanco | Fecha: 01/01/2012

Auricular reconstruction remains one of the biggest challenges faced by plastic surgeons. Reconstruction with autologous cartilage has proven to offer a lasting reconstruction with acceptable cosmetic results when performed by very experienced surgeons; however, the learning curve is long and few surgeons around the world have mastered this technique. For less experienced surgeons clinical outcome is frequently wanting; moreover, reconstructions with autologous cartilage carry its own burden of donor site morbidity and surgical complications. In order to reduce operating time, avoid the risks and complications inherent of cartilage harvest and homogenize clinical outcome of ear reconstruction, auricular off the shelf scaffolds have been manufactured using biomaterial.The only auricular scaffold present in the market today is made of high density porous polyethylene and commercialized under the trade name Medpor®. Despite its limited success porous polyethylene has not fully convinced surgeons due to its stiffness and extrusion rates. A novel nanocomposite polymer has been developed by Prof. Seifalian and its team at UCL by the incorporation of polyhedral oligomeric silsesquioxane (POSS) nanocage as pendant side chains into poly (carbonate-urea) urethane. POSS PCU can be shaped as an auricle, it mimics the elastic properties of auricular native cartilage and supports cell growth and proliferation. In this project we have used human dermal fibroblasts primary cells (HFF) to study and compare cellular response on POSS PCU and Medpor®.In vitro experiments detected significantly higher cell adhesion on POSS PCU when compared to Medpor® (p < 0,05). Dynamic condition at 50 RMP was found reduce cell attachment on both polymers; under this condition POSS PCU supports higher cell adhesion than Medpor®. Even though no difference on cell proliferation or metabolic activity per cell was found between the two polymers, POSS PCU, with higher cell adhesion, have higher overall cell proliferation and metabolic activity. Collagen production per cell was found to be significantly increased on Medpor®; however, the higher cell number found on POSS PCU managed to produce as much total collagen as its counterpart. Even though POSS PCU is non-degradable, HFF were found to lower POSS PCU young’s modulus and make the scaffolds more flexible. Even though further refinement of POSS PCU scaffold production and the need for additional in vitro and in vivo studies, this biomaterial is a promising alternative for auricular reconstruction.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Tesis
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Auricular reconstruction with a nanocomposite polymer = Reconstrucción auricular con un nanopolimero

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Imagen de apoyo de  Autophagy Proteins ATG5 and ATG7 Are Essential for the Maintenance of Human CD34(+) Hematopoietic Stem-Progenitor Cells

Autophagy Proteins ATG5 and ATG7 Are Essential for the Maintenance of Human CD34(+) Hematopoietic Stem-Progenitor Cells

Por: María Catalina; Folkerts Gómez Puerto | Fecha: 01/01/2016

Abstract:Autophagy is a highly regulated catabolic process that involves sequestration and lysosomal degradation of cytosolic components such as damaged organelles and misfolded proteins. While autophagy can be considered to be a general cellular housekeeping process, it has become clear that it may also play cell type-dependent functional roles.In this study, we analyzed the functional importance of autophagy in human hematopoietic stem/progenitor cells (HSPCs), and how this is regulated during differentiation. Western blot-based analysis of LC3-II and p62 levels, as well as flow cytometry-based autophagic vesicle quantification, demonstrated that umbilical cord blood-derived CD34(+) /CD38(-) immature hematopoietic progenitors show a higher autophagic flux than CD34(+) /CD38(+) progenitors and more differentiated myeloid and erythroid cells.This high autophagic flux was critical for maintaining stem and progenitor function since knockdown of autophagy genes ATG5 or ATG7 resulted in reduced HSPC frequencies in vitro as well as in vivo. The reduction in HSPCs was not due to impaired differentiation, but at least in part due to reduced cell cycle progression and increased apoptosis.This is accompanied by increased expression of p53, proapoptotic genes BAX and PUMA, and the cell cycle inhibitor p21, as well as increased levels of cleaved caspase-3 and reactive oxygen species. Taken together, our data demonstrate that autophagy is an important regulatory mechanism for human HSCs and their progeny, reducing cellular stress and promoting survival.Resumen: La autofagia es un proceso lisosomal catabólico altamente regulado que implica el secuestro y degradación de componentes citosólicos: tales como proteínas mal plegadas y orgánelos deteriorados. Mientras que la autofagia puede ser considerada como un proceso general de limpieza celular, también juega un papel funcional dependiendo del tipo de célula.En el presente estudio, hemos analizado la importancia de la autofagia en las células madre hematopoyéticas y sus progenitores y cómo dicho proceso está regulado durante la diferenciación. El análisis de los niveles de LC3-II y p62, así como la cuantificación de la autofagia mediante citometría de flujo demostraron que los progenitores hematopoyéticos inmaduros CD34 (+) / CD38 (-) tienen un flujo de autofagia mayor que las células eritroides y mieloides. Este alto flujo de autofagia es crucial para las células madre y los progenitores hematopoyéticos inmaduros CD34 (+) / CD38 (-) ya que la disminución en los niveles de ATG7 y ATG5 resulta en una reducción de dichas células tanto in vitro como in vivo.Lo anterior es consecuencia de la inhibición parcial del ciclo celular y de un aumento en apoptosis. Adicionalmente, observamos un incremento en la expresión de p53, los genes pro-apoptosis BAX y PUMA, el inhibidor de ciclo celular p21, los niveles de caspasa-3 clivada y las especies reactivas del oxígeno.En conclusión, nuestros datos demuestran que la autofagia es un mecanismo de regulación importante para las células madre hematopoyéticas y sus progenitores reduciendo los niveles de estrés y promoviendo su supervivencia.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Autophagy Proteins ATG5 and ATG7 Are Essential for the Maintenance of Human CD34(+) Hematopoietic Stem-Progenitor Cells

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Imagen de apoyo de  Beneficencia pública: 30 de Septiembre de 1881

Beneficencia pública: 30 de Septiembre de 1881

Por: Manuel Plata Azuero | Fecha: 01/01/1881

Documento que el presidente de la Junta de beneficencia de Bogotá, Manuel Samper, envía a los miembros de la Asamblea legislativa de Cundinamarca, con el fin de señalar las dificultades que tiene la Junta para poder desarrollar proyectos que mejoren la calidad de servicio y salud del Hospital de la Caridad. El documento se redacta en nombre de varios miembros de la junta, quienes consideran que no se les advirtió sobre las problemáticas existentes antes de que aceptaran se parte del grupo de beneficencia.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Prensa
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Beneficencia pública: 30 de Septiembre de 1881

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Imagen de apoyo de  Biofunctionalization of REDV elastin-like recombinamers improves endothelialization on CoCr alloy surfaces for cardiovascular applications

Biofunctionalization of REDV elastin-like recombinamers improves endothelialization on CoCr alloy surfaces for cardiovascular applications

Por: María Isabel; Gil Castellanos Arboleda | Fecha: 01/01/2015

To improve cardiovascular implant success, metal-based stents are designated to modulate endothelial cells adhesion and migration in order to prevent restenosis and late thrombosis diseases. Biomimetic coatings with extra-cellular matrix adhesive biomolecules onto stents surfaces are a strategy to recover a healthy endothelium.However, the appropriate bioactive sequences to selective promote growth of endothelium and the biomolecules surface immobilization strategy remains to be elucidated. In this study, biofunctionalization of cobalt chromium, CoCr, alloy surfaces with elastin-like recombinamers, ELR, genetically modified with an REDV sequence, was performed to enhance metal surfaces endothelialization.Moreover, physical adsorption and covalent bonding were used as biomolecules binding strategies onto CoCr alloy. Surfaces were activated with plasma and etched with sodium hydroxide previous to silanization with 3-chloropropyltriethoxysilane and functionalized with the ELR. CoCr alloy surfaces were successfully biofunctionalized and the use of an ELR with an REDV sequence, allows conferring bioactivity to the biomaterials surface, demonstrating a higher cell adhesion and spreading of HUVEC cells on the different CoCr surfaces.This effect is emphasized as increases the amount of immobilized biomolecules and directly related to the immobilization technique, covalent bonding, and the increase of surface charge electronegativity. Our strategy of REDV elastin-like recombinamers immobilization onto CoCr alloy surfaces via covalent bonding through organosilanes provides a bioactive surface that promotes endothelial cell adhesion and spreading.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Biofunctionalization of REDV elastin-like recombinamers improves endothelialization on CoCr alloy surfaces for cardiovascular applications

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Imagen de apoyo de  BMP type II receptor as a therapeutic target in pulmonary arterial hypertension = BMPR2 como diana terapeutica en la hipertensión arterial pulmon

BMP type II receptor as a therapeutic target in pulmonary arterial hypertension = BMPR2 como diana terapeutica en la hipertensión arterial pulmon

Por: María Catalina; Orriols Gómez Puerto | Fecha: 01/01/2017

Pulmonary arterial hypertension (PAH) is a chronic disease characterized by a progressive elevation in mean pulmonary arterial pressure. This occurs due to abnormal remodeling of small peripheral lung vasculature resulting in progressive occlusion of the artery lumen that eventually causes right heart failure and death. The most common cause of PAH is inactivating mutations in the gene encoding a bone morphogenetic protein type II receptor (BMPRII). Current therapeutic options for PAH are limited and focused mainly on reversal of pulmonary vasoconstriction and proliferation of vascular cells. Although these treatments can relieve disease symptoms, PAH remains a progressive lethal disease. Emerging data suggest that restoration of BMPRII signaling in PAH is a promising alternative that could prevent and reverse pulmonary vascular remodeling. Here we will focus on recent advances in rescuing BMPRII expression, function or signaling to prevent and reverse pulmonary vascular remodeling in PAH and its feasibility for clinical translation. Furthermore, we summarize the role of described miRNAs that directly target the BMPR2 gene in blood vessels. We discuss the therapeutic potential and the limitations of promising new approaches to restore BMPRII signaling in PAH patients. Different mutations in BMPR2 and environmental/genetic factors make PAH a heterogeneous disease and it is thus likely that the best approach will be patient-tailored therapies.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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BMP type II receptor as a therapeutic target in pulmonary arterial hypertension = BMPR2 como diana terapeutica en la hipertensión arterial pulmon

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Imagen de apoyo de  Cambios recientes en las principales causas de mortalidad en Colombia

Cambios recientes en las principales causas de mortalidad en Colombia

Por: Karina; Romero Prieto Acosta Ordoñez | Fecha: 01/01/2014

Este documento estima la reducción de la esperanza de vida al nacer y la pérdida de años de vida productivos, debido a las principales causas de muertes en Colombia. Asimismo, se calculó la probabilidad de muerte por causas y cuando se alcanzan ciertos grupos de edad. Estos ejercicios fueron basados en tablas de vida con múltiples causas de salida y utilizando escenarios hipotéticos de eliminación de causas de muertes. Se encontró que entre 1990 y 2012 se han experimentado notables cambios en el perfil epidemiológico, así como el aumento de la esperanza de vida, esta presenta un rezago de veinte años en comparación con países más desarrollados. En los últimos años, las enfermedades del sistema circulatorio se han convertido en el mayor factor explicativo de la reducción de la esperanza de vida al nacer. En los hombres, cobra importancia los homicidios y otras causas externas, las cuales son el principal factor de riesgo de muerte en las edades más productivas.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Series monográficas
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Cambios recientes en las principales causas de mortalidad en Colombia

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Imagen de apoyo de  Cardiac-specific overexpression of thioredoxin 1 attenuates mitochondrial and myocardial dysfunction in septic mice

Cardiac-specific overexpression of thioredoxin 1 attenuates mitochondrial and myocardial dysfunction in septic mice

Por: Juana Patricia; D’Annunzio Sánchez Villamil | Fecha: 01/01/2016

Abstract:Sepsis-induced myocardial dysfunction is associated with increased oxidative stress and mitochondrial dysfunction. Current evidence suggests a protective role of thioredoxin-1 (Trx1) in the pathogenesis of cardiovascular diseases. However, it is unknown yet a putative role of Trx1 in sepsis-induced myocardial dysfunction, in which oxidative stress is an underlying cause.Transgenic male mice with Trx1 cardiac-specific overexpression (Trx1-Tg) and its wild-type control (wt) were subjected to cecal ligation and puncture or sham surgery. After 6, 18, and 24 h, cardiac contractility, antioxidant enzymes, protein oxidation, and mitochondrial function were evaluated. Trx1 overexpression improved the average life expectancy (Trx1-Tg: 36, wt: 28 h; p=0.0204).Sepsis induced a decrease in left ventricular developed pressure in both groups, while the contractile reserve, estimated as the response to ?-adrenergic stimulus, was higher in Trx1-Tg in relation to wt, after 6 h of the procedure. Trx1 overexpression attenuated complex I inhibition, protein carbonylation, and loss of membrane potential, and preserved MnSOD activity at 24 h.Ultrastructural alterations in mitochondrial cristae were accompanied by reduced Optic atrophy 1 (OPA1) fusion protein, and activation of dynamin-related protein 1 (Drp1) (fission protein) in wt mice at 24 h, suggesting mitochondrial fusion/fission imbalance. PGC-1? gene expression showed a 2.5-fold increase in Trx1-Tg at 24 h, suggesting mitocondrial biogenesis induction. Autophagy, demonstrated by electron microscopy and increased LC3-II/LC3-I ratio, was observed earlier in Trx1-Tg. In conclusion, Trx1 overexpression extends antioxidant protection, attenuates mitochondrial damage, and activates mitochondrial turnover (biogenesis and mitophagy), preserves contractile reserve and prolongs survival during sepsis.Resumen: La disfunción miocárdica inducida por sepsis está asociada con estrés oxidativo y disfuncion mitocontrial. La evidencia actual sugiere un rol protector de thiorredoxina 1 en la patogénesis de la enfermedad cardiovascular. Sin embargo, es desconocido su papel en la disfunción miocárdica inducida por sepsis, en el cual el estrés oxidativo es una causa subyacente. Ratones transgénicos machos con sobreexpresión específica en músculo cardiaco (Trx1-Tg) y su control (wt) fueron sujetos a ligadura punción cecal o técnica de laparotomía sin ligadura y punción (sham). Después de 6, 18,y 24h, contractilidad cardiaca, enzimas antioxidantes, oxidación de proteínas, y función mitocondrial fueron evaluados. Sobre-expresión de Trx1 mejoró la esperanza de vida media (Trx1-Tg: 36, wt: 28 h; p = 0.0204). Sepsis indujo una reducción en la presión desarrollada del ventrículo izquierdo en ambos grupos, mientras la reserva contráctil, estimada como la respuesta al estímulo β-adrenérgico, fue superior en Trx1-Tg en relación a wt, posterior a 6 h del procedimiento.La sobre-expresión de Trx1 atenuó la inhibición del complejo I, carbonilación de proteínas, y pérdida de potencial de membrana, y preservó la actividad de la superóxido dismutasa-Mn a las 24 h. Alteraciones ultra estructurales en las crestas mitocondriales fueron acompañadas por una reducción en OPA1 y activación de Drp1 en ratones wt a las 24 h, sugiriendo un imbalance fusión/fisión mitocondrial. La expresión de PGC-1-α incrementó 2.5 veces en Trx1-Tg a las 24 h, sugiriendo inducción de biogénesis mitocondrial. Autofagia, demostrada por microscopia electrónica e incremento en la razón LC3-II/LC3-I, fue observado más tempranamente en Trx1-Tg. En conclusión, la sobre-expresión de Trx1 extiende protección antioxidante, atenúa el daño mitocondrial y activa el recambio mitocondrial (mitofagia y biogénesis), preserva la reserva contráctil y prolonga la sobrevida durante la sepsis.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Cardiac-specific overexpression of thioredoxin 1 attenuates mitochondrial and myocardial dysfunction in septic mice

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