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Search Results: 1 - 10 of 250117 matches for " Juan C Bustos-Valenzuela "
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Unveiling novel genes upregulated by both rhBMP2 and rhBMP7 during early osteoblastic transdifferentiation of C2C12 cells
Juan C Bustos-Valenzuela, Andre Fujita, Erik Halcsik, Jose M Granjeiro, Mari C Sogayar
BMC Research Notes , 2011, DOI: 10.1186/1756-0500-4-370
Abstract: BMPs (bone morphogenetic proteins) are members of the TGFβ (transforming growth factor-β) super-family of proteins, which regulate growth and differentiation of different cell types in various tissues, and play a critical role in the differentiation of mesenchymal cells into osteoblasts. In particular, rhBMP2 and rhBMP7 promote osteoinduction in vitro and in vivo, and both proteins are therapeutically applied in orthopaedics and dentistry.Using DNA microarrays and RT-qPCR, we identified both previously known and novel genes which are upregulated by rhBMP2 and rhBMP7 during the onset of osteoblastic transdifferentiation of pre-myoblastic C2C12 cells. Subsequent studies of these genes in C2C12 and mesenchymal or pre-osteoblastic cells should reveal more details about their role during this type of cellular differentiation induced by BMP2 or BMP7. These studies are relevant to better understanding the molecular mechanisms underlying osteoblastic differentiation and bone repair.Bone formation and fracture repair depends on the expression and action of the bone morphogenetic proteins (BMPs), which are members of the transforming growth factor beta (TGF-beta) superfamily of dimeric, disulphide-linked growth factors, comprising more than 15 related proteins. In addition to a crucial role in osteogenesis, BMPs display a myriad of roles in cell proliferation, differentiation, migration and apoptosis, in different cell types [1]. Their role is essential at early phases of development and organogenesis, such as axial embryo determination [2], as well as in limb, eye and kidney development, such that ablation of these genes results in death at very early stages of development, as observed in knock-out mice [3]. In humans, recombinant BMP2 and BMP7 have gained attention in bone repair and in non-union spinal fractures due to their capacity to stimulate the differentiation of mesenchymal stem cells from the periosteum near the lesion site after migration and proliferation induced
Bone morphogenetic proteins: from structure to clinical use
Granjeiro, J.M.;Oliveira, R.C.;Bustos-Valenzuela, J.C.;Sogayar, M.C.;Taga, R.;
Brazilian Journal of Medical and Biological Research , 2005, DOI: 10.1590/S0100-879X2005001000003
Abstract: bone morphogenetic proteins (bmps) are multi-functional growth factors belonging to the transforming growth factor ? superfamily. family members are expressed during limb development, endochondral ossification, early fracture, and cartilage repair. the activity of bmps was first identified in the 1960s but the proteins responsible for bone induction were unknown until the purification and cloning of human bmps in the 1980s. to date, about 15 bmp family members have been identified and characterized. the signal triggered by bmps is transduced through serine/threonine kinase receptors, type i and ii subtypes. three type i receptors have been shown to bind bmp ligands, namely: type ia and ib bmp receptors and type ia activin receptors. bmps seem to be involved in the regulation of cell proliferation, survival, differentiation and apoptosis, but their hallmark is their ability to induce bone, cartilage, ligament, and tendon formation at both heterotopic and orthotopic sites. this suggests that, in the future, they may play a major role in the treatment of bone diseases. several animal studies have illustrated the potential of bmps to enhance spinal fusion, repair critical-size defects, accelerate union, and heal articular cartilage lesions. difficulties in producing and purifying bmps from bone tissue have prompted the attempts made by several laboratories, including ours, to express these proteins in the recombinant form in heterologous systems. this review focuses on bmp structure, molecular mechanisms of action and significance and potential applications in medical, dental and veterinary practice for the treatment of cartilage and bone-related diseases.
Bone morphogenetic proteins: from structure to clinical use
Granjeiro J.M.,Oliveira R.C.,Bustos-Valenzuela J.C.,Sogayar M.C.
Brazilian Journal of Medical and Biological Research , 2005,
Abstract: Bone morphogenetic proteins (BMPs) are multi-functional growth factors belonging to the transforming growth factor superfamily. Family members are expressed during limb development, endochondral ossification, early fracture, and cartilage repair. The activity of BMPs was first identified in the 1960s but the proteins responsible for bone induction were unknown until the purification and cloning of human BMPs in the 1980s. To date, about 15 BMP family members have been identified and characterized. The signal triggered by BMPs is transduced through serine/threonine kinase receptors, type I and II subtypes. Three type I receptors have been shown to bind BMP ligands, namely: type IA and IB BMP receptors and type IA activin receptors. BMPs seem to be involved in the regulation of cell proliferation, survival, differentiation and apoptosis, but their hallmark is their ability to induce bone, cartilage, ligament, and tendon formation at both heterotopic and orthotopic sites. This suggests that, in the future, they may play a major role in the treatment of bone diseases. Several animal studies have illustrated the potential of BMPs to enhance spinal fusion, repair critical-size defects, accelerate union, and heal articular cartilage lesions. Difficulties in producing and purifying BMPs from bone tissue have prompted the attempts made by several laboratories, including ours, to express these proteins in the recombinant form in heterologous systems. This review focuses on BMP structure, molecular mechanisms of action and significance and potential applications in medical, dental and veterinary practice for the treatment of cartilage and bone-related diseases.
Fracturas en madera de Eucalyptus nitens: efecto de las propiedades mecánicas a nivel ultraestructural y de la anatomía celular
Valenzuela C,Paulina; Bustos A,Cecilia; Lasserre,Jean Pierre; Gacitúa E,William;
Maderas. Ciencia y tecnología , 2012, DOI: 10.4067/S0718-221X2012000200009
Abstract: this study was conducted to investigate the causes and posibles factors related to fractures in the cellular structure in eucalyptus nitens. nanomechanical cell wall properties at the middle lamella level (ml), s1 and s2 layers were evaluated. in addition, the area, and diameter of vessels were measured. these parameters were associated with extreme levels of cracking (high and low) in two eucalyptus nitens families. the samples were taked from two sites of the 8th region of chile. the analysis of the ductility ratio (e/h) demonstrated that the ml is more brittle than the s1 layer; and the s1 is more brittle than s2 layer. the ml and s1 layer behave like resilient materials, but not the s2 layer. the difference in the modulus of resilience was related to higher shear stresses at the ml/s2 and at s1/s2 interfaces. the characterization of the vessels showed that the families with greater level of cracking have also lower frequency and greater area and diameter of vessels the s1 layer was weaker tan s2 layer and lm due to their difference in resistance between them and combined with the internal stresses might propagate the microcracks.
Caracterización nanomecánica de la estructura celular y anatómica de Eucalyptus nitens y su relación con la frecuencia de grietas y rajaduras en madera redonda
Valenzuela C,Paulina; Bustos A,Cecilia; Lasserre,Jean Pierre; Gacitúa E,William;
Maderas. Ciencia y tecnología , 2012, DOI: 10.4067/S0718-221X2012005000006
Abstract: the aim of this study was to define the minimum volumen in trees of e. nitens that characterize the mechanical and anatomy behavior for non-destructive sampling. the trees were cut from sites located in mulchen and yungay in the region of bío bío. relationships were found between nanomechanical properties, wood anatomy and wood cracks and fractures. the response variables were the ductility ratio (e/h) and the modulus of resilience (ur), in the s2 layer and middle lamella. the results showed that the representative volume, from e. nitens families is at 3 meter high from base of the trees and between the 5th to 7th annual rings. also, it was established that the middle lamella is more brittle than the s2 layer. relationship between the vessels morphology and the level of the wood cracking was observed. a high area of vessels, a high vessel diameter and a small frequency of them, resulted in high cracking. the cracks were mainly concentrated in the first meters of tree, were we found a good relationship of this response variable with the e/h ratio for the middle lamella; there was a significant change of this ratio at 3 meters high. cracks were evident on earlywood and from the 5th to the 7th annual rings.
Fracturas en madera de Eucalyptus nitens: efecto de las propiedades mecánicas a nivel ultraestructural y de la anatomía celular Fracture in Eucalyptus nitens wood: effect of nanomechanical properties, ultrastructure and anatomical level
Paulina Valenzuela C,Cecilia Bustos A,Jean Pierre Lasserre,William Gacitúa E
MADERAS : Ciencia y Tecnología , 2012,
Abstract: Se realizó un estudio para indagar en las causas y posibles factores que originan la fractura en la estructura de la madera de Eucalyptus nitens. Para esto se examinó el comportamiento nanomecánico de la lamela media (LM), de las capas S1 y S2 de la pared celular. También se determinaron el número, área y diámetro de los vasos que están asociados a niveles de agrietamiento extremos (alto y bajo). Se estudiaron dos familias de Eucalyptus nitens procedentes de dos sitios de la 8va Región de Chile. Mediante el cálculo y análisis de la razón de ductilidad (E/H), se determinó que la LM es más quebradiza que la capa S1, y ésta a su vez más quebradiza que la capa S2; existiendo diferencias significativas en la ductilidad de estas capas. La LM y capa S1 se comportan como materiales resilientes, no así la capa S2. La diferencia en el módulo de resiliencia se relacionó con las mayores tensiones de corte que se presentaron en las interfaces LM/S2 y S1/S2. La caracterización de los vasos mostró que la familia con nivel de agrietamiento mayor, tiene mayor frecuencia, área y diámetro de vasos, los cuales contribuyen a la concentración de esfuerzos en la estructura celular de la madera. Los resultados evidenciaron que la capa S1 fue más débil que la capa S2 y LM dada la diferencia en resistencia entre ellas y que complementado con las tensiones internas que se generan en el proceso de crecimiento del árbol se producen las microgrietas. This study was conducted to investigate the causes and posibles factors related to fractures in the cellular structure in Eucalyptus nitens. Nanomechanical cell wall properties at the middle lamella level (ML), S1 and S2 layers were evaluated. In addition, the area, and diameter of vessels were measured. These parameters were associated with extreme levels of cracking (high and low) in two Eucalyptus nitens families. The samples were taked from two sites of the 8th Region of Chile. The analysis of the ductility ratio (E/H) demonstrated that the ML is more brittle than the S1 layer; and the S1 is more brittle than S2 layer. The ML and S1 layer behave like resilient materials, but not the S2 layer. The difference in the modulus of resilience was related to higher shear stresses at the ML/S2 and at S1/S2 interfaces. The characterization of the vessels showed that the families with greater level of cracking have also lower frequency and greater area and diameter of vessels The S1 layer was weaker tan S2 layer and LM due to their difference in resistance between them and combined with the internal stresses might propagate the microcracks.
Caracterización nanomecánica de la estructura celular y anatómica de Eucalyptus nitens y su relación con la frecuencia de grietas y rajaduras en madera redonda Characterization nanomechanics of wood cell structure and anatomy in Eucalyptus nitens and its relation to the cracking and fractures in round wood
Paulina Valenzuela C,Cecilia Bustos A,Jean Pierre Lasserre,William Gacitúa E
MADERAS : Ciencia y Tecnología , 2012,
Abstract: El objetivo de este trabajo fue localizar el mínimo volumen en árboles de E. nitens que caracterice el comportamiento mecánico y anatómico para un muestreo no destructivo. Los árboles fueron cortados desde Mulchén y Yungay en la región del Bío-Bío. Se establecieron relaciones entre las propiedades nanomecánicas y la anatomía de la madera con el agrietamiento y las fracturas mayores (rajaduras). Se obtuvieron los parámetros razón de ductilidad (E/H) y módulo de resiliencia (u r), medidos en la capa S2 y lamela media. Los resultados mostraron que el volumen representativo de los árboles de E. nitens se encontraban a 3 metros de altura desde la base de los árboles y desde el anillo 5 al 7. Al mismo tiempo, se logró establecer que la lamela media es más frágil que la capa S2 de la pared celular. Se determinó una relación entre la caracterización de los vasos y el nivel de agrietamiento de la madera. Esto es, a mayor área y diámetro de los vasos y a menor número de éstos, el nivel de agrietamiento fue mayor. Las grietas se concentraron principalmente en los primeros metros de altura del árbol, existiendo una buena relación con el E/H de la lamela media, que mostró un cambio significativo a los 3 metros de altura. Las grietas en los anillos de crecimiento se centraron notoriamente en madera de temprana y en los anillos del 5 al 7 (desde médula a corteza). The aim of this study was to define the minimum volumen in trees of E. nitens that characterize the mechanical and anatomy behavior for non-destructive sampling. The trees were cut from sites located in Mulchen and Yungay in the region of Bío Bío. Relationships were found between nanomechanical properties, wood anatomy and wood cracks and fractures. The response variables were the ductility ratio (E/H) and the modulus of resilience (u r), in the S2 layer and middle lamella. The results showed that the representative volume, from E. nitens families is at 3 meter high from base of the trees and between the 5th to 7th annual rings. Also, it was established that the middle lamella is more brittle than the S2 layer. Relationship between the vessels morphology and the level of the wood cracking was observed. A high area of vessels, a high vessel diameter and a small frequency of them, resulted in high cracking. The cracks were mainly concentrated in the first meters of tree, were we found a good relationship of this response variable with the E/H ratio for the middle lamella; there was a significant change of this ratio at 3 meters high. Cracks were evident on earlywood and from the 5th to the 7th annual rings.
EVALUACIóN NEONATAL DEL CRECIMIENTO INTRAUTERINO DE RECIéN NACIDOS EN HOSPITAL REGIONAL DE TEMUCO: COMPARACION CON TRES ESTáNDARES NACIONALES
Lagos S,Rudecindo; Bustos M,Luis; Orellana C,Juan José;
Revista chilena de obstetricia y ginecología , 2009, DOI: 10.4067/S0717-75262009000400002
Abstract: background: birth weight, length, skull perimeter and neonatal ponderal index, according to gestational age, are important indicators of fetal growth. who recommend, build local standard for better assessment in fetal growth changes. objective: to determine local neonatal intrauterine growth curve according to gestational age and birth weight, and compared with other chilean standards. method: a cross-sectional study in 57,470 births, born between the 24th and 42th weeks of gestation (temuco-chile, 1994-2007). percentil distribution (p3, p5, p10, p50 and p90) of neonatal variables (weight, height, ponderal index and skull perimeter) were calculated. results: our curve in comparison with the others chilean fetal growth standard (fetal growth curve of juez, alarcón, and gonzález, respectively) show differences in the population under p10 (8.2%, 7.8% and 4.2%, respectively), and over p90 (14.5%, 15.2% and 17.4%, respectively). conclusion: it was observed significant differences in fetal growth classifications, between temuco standard with the others 3 chilean curves, especially with the national standard who include not selected obstetric population.
EVALUACIóN NEONATAL DEL CRECIMIENTO INTRAUTERINO DE RECIéN NACIDOS EN HOSPITAL REGIONAL DE TEMUCO: COMPARACION CON TRES ESTáNDARES NACIONALES
Rudecindo Lagos S,Luis Bustos M,Juan José Orellana C
Revista Chilena de Obstetricia y Ginecología , 2009,
Abstract: Antecedentes: El peso, la talla, el perímetro del cráneo y el índice ponderal neonatal según la edad gesta-cional, son importantes indicadores del crecimiento intrauterino. La OMS recomienda para los distintos centros perinatologicos confeccionar y actualizar gráficas y tablas que permitan valorar mejor las alteraciones del crecimiento fetal. Objetivo: Construir una curva neonatal local de crecimiento intrauterino según edad gestacional, y comparar el peso neonatal con otras curvas chilenas. Método: Estudio de corte transversal en 57.470 partos de población obstétrica seleccionada, nacidos entre las 24 y 42 semanas de gestación, atendidos en el Hospital Regional de Temuco, durante los a os 1994-2007. Se obtuvo para las variables neonatales (peso, talla, cráneo e índice ponderal neonatal) la distribución percentilar (p3, p5, p10 p50y p90) por edad gestacional. Resultados: En el criterio de Temuco la distribución del peso neonatal fue de 80% adecuados, 10% peque os y 10% grandes para la edad gestacional. Con los estándares de comparación (curvas de crecimiento intrauterino de Juez, Alarcón y González, respectivamente) encontramos diferencias para la proporción de recién nacidos bajo p10 de 8,2%, 7,8% y 4,2%, respectivamente, y en categoría grandes para la edad gestacional de 14,5%, 15,2% y 17,4%, respectivamente. Conclusión: La comparación de nuestra curva local con los tres estándares chilenos, permite detectar diferencias significativas de crecimiento fetal, especialmente con el estándar nacional que incluye población obstétrica no seleccionada. Background: Birth weight, length, skull perimeter and neonatal ponderal index, according to gestational age, are important indicators of fetal growth. WHO recommend, build local standard for better assessment in fetal growth changes. Objective: To determine local neonatal intrauterine growth curve according to gestational age and birth weight, and compared with other Chilean standards. Method: A cross-sectional study in 57,470 births, born between the 24th and 42th weeks of gestation (Temuco-Chile, 1994-2007). Percentil distribution (p3, p5, p10, p50 and p90) of neonatal variables (weight, height, ponderal index and skull perimeter) were calculated. Results: Our curve in comparison with the others Chilean fetal growth standard (fetal growth curve of Juez, Alarcón, and González, respectively) show differences in the population under p10 (8.2%, 7.8% and 4.2%, respectively), and over p90 (14.5%, 15.2% and 17.4%, respectively). Conclusion: It was observed significant differences in fetal growth classifications, betw
SINDROME DE EINSENMENGER Y EMBARAZO
Acu?a S.,Margot; Inostroza C.,Alexis; Bustos V.,Juan Carlos; Alvarez C.,Carlos;
Revista chilena de obstetricia y ginecología , 2002, DOI: 10.4067/S0717-75262002000400009
Abstract: we present a clinical case of a 21 year old patient, in her second pregnancy (multiparous 1), with the diagnose of einsenmenger's syndrome. the diagnosis was made after her first delivery. she was admitted at the high risk obstetric unit during her 14 week of the second pregnancy. on admission she had functional capacity (fc) iii and oxygen-dependent. she was managed medically up to 28 weeks; due to the progressive maternal compromise with vital risks and fetal damage, a preterm cesarean section was perfomed by a multicentric and multidisciplinary team. the result was a newborn alive, and during the intervention there weren't anesthetical or surgical incidents. the patient was, since the delivery, with hemodinamic instability and cardiogenic shock. she died 39 hours after the delivery, despite all medical efforts. we review the einsenmenger's syndrome, the actual management, bad prognosis and the need of preventing pregnancy in these patients due to the high maternal mortality risk and fetal compromise
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