Nuestra Experiencia en el Estudio con Ultrasonografía en la Cadera Neonatal

Se estudian mediante ultrasonografía las caderas de 112 recién nacidos (224 caderas) con signos clínicos de displasia luxante de cadera. Los resultados se comparan con los datos de exploración clínica y estudio radiográ- fico poniendo en evidencia las limitaciones diagnósticas de las maniobras exploratorias clásicas y la radiografía. Concluye que la ultrasonografía es el método más seguro e inocuo para el diagnóstico precoz de la displasia luxante de cadera en el recién nacido.The authors are studied by ultrasonography 112 newborns (224 hips) with clinical signs of congenital dysplasia and dislocation of the hip. The results obtained are compared with clinical findings and radiographic study emphasizing the diagnostic limitations of the clasics maneuvistes of physical examination and radiography. They conclude that the ultrasonography is the most sure method and innocuous to the early diagnosis of the congenital dysplasia and dislocation of the hip at the newborn

Los Ultrasonidos en la Cadera Neonatal

Los autores describen la técnica de Estudio mediante Ecografía de la cadera neonatal, las imágenes normales, los métodos de mediciones y las características de los distintos grados de displasiaThe authors describe the technique of the study by ultrasound examination of neonatal hip, normal images, methods of measurement and characteristics of differents degrees of dysplasi

V centers in MgAl2O4 spinels

V centers induced by ionizing irradiation at 80 or 300 K in single-crystal and polycrystalline MgAl2O4 samples have been studied by use of electron paramagnetic resonance and optical absorption. Vt- and Vo2- centers, as a result of hole trapping at tetrahedral and octahedral cation vacancies, respectively, have been found to be responsible for two EPR bands centered at g=2.011 and optical absorption bands involved in the complex absorption spectrum at about 3.4 eV. These centers anneal thermally in a very wide step from 220 to 575 K. © 1991 The American Physical SocietyPeer Reviewe

Estudio de la biocompatibilidad in vitro de polimeros metacrílicos derivados de pirrolidona-ina

Este estudio analiza la biocompatibilidad de nuevos biomateriales a base de hidrogeles metacrílicos como el poli-[metacrilato de 2-etil-(2-pirrolidona)] (PEPM) y la poli-[metacrilato de 2-etil-(2-pirrolidina)], en comparación con referentes comerciales tales como la poli-(vinil pirrolidona) (PVP) y la poli-(N-N´-dimetilacrilamida) (PDMA). Se utilizaron propiedades bioquímicas, mediante los ensayos de MTT y Alamar Blue, para conocer el efecto de citotoxicidad y proliferación en cultivo de fibroblastos (células VERO), sobre los biomateriales metacrílicos. Adicionalmente, por microscopía óptica y electrónica fueron analizados el grado de adhesión, morfología, muerte celular, proliferación, contracción celular, etc. Además se estudiaron las relaciones entre citotoxicidad y estructura química. En el MTT y en el análisis óptico se obtuvo baja citotoxicidad para PEPM y PVP, media en PEPyM y alta en PDMA. En el Alamar Blue y SEM se produjo una media proliferación-adhesión en PEPM y PEPyM, alta en PVP y muerte celular en PDMA. Sus apropiadas características físico-químicas y su aceptable grado de biocompatibilidad les hacen buenos candidatos en aplicaciones tales como lentes de contacto, sistemas de liberación de fármacos e ingeniería de tejidos.This study analyzed biocompatibility of new biomaterials based on the methacrylic hydrogels derived poly-[2-ethyl-(2-pyrrolidone) methacrylate] (PEPM) and poly-[2-ethyl-(2-pyrrolidine) methacrylate] (PEPyM), in comparison with references such as commercial poly-(vinyl pyrrolidone) (PVP) and poly-(N, N-dimethylacrylamide) (PDMA). The biochemical properties were used to know citotoxicity and proliferation effect over fibroblast culture (VERO cells) in contact with the methacrylic biomaterials, using MTT and Alamar Blue assays. Additionally, were analyzed adhesion grade, morphology, death cell presence, proliferation, cell contraction, etc, by optical and scanning electronic microscopy (SEM). The relationships between their chemical structures and cytotoxicity were studied. In MTT and optical analysis, low cytotoxicity was found for PEPM and PVP, medium in the case of PEPyM, and high for PDMA. In Alamar Blue and SEM, were produced a medium proliferation and adhesion rate for PEPM and PEPyM, high in PVP, and cellular death for PDMA. Their appropriates physico-chemical characteristics and approval biocompatibility grade make them good candidates in applications such as contact lenses, drug release systems and tissue engineering

Magnetite mineralization inside cross-linked protein crystals

Crystallization in confined spaces is a widespread process in nature that also has important implications for the stability and durability of many man-made materials. It has been reported that confinement can alter essential crystallization events, such as nucleation and growth and, thus, have an impact on crystal size, polymorphism, morphology, and stability. Therefore, the study of nucleation in confined spaces can help us understand similar events that occur in nature, such as biomineralization, design new methods to control crystallization, and expand our knowledge in the field of crystallography. Although the fundamental interest is clear, basic models at the laboratory scale are scarce mainly due to the difficulty in obtaining well-defined confined spaces allowing a simultaneous study of the mineralization process outside and inside the cavities. Herein, we have studied magnetite precipitation in the channels of cross-linked protein crystals (CLPCs) with different channel pore sizes, as a model of crystallization in confined spaces. Our results show that nucleation of an Fe-rich phase occurs inside the protein channels in all cases, but, by a combination of chemical and physical effects, the channel diameter of CLPCs exerted a precise control on the size and stability of those Fe-rich nanoparticles. The small diameters of protein channels restrain the growth of metastable intermediates to around 2 nm and stabilize them over time. At larger pore diameters, recrystallization of the Fe-rich precursors into more stable phases was observed. This study highlights the impact that crystallization in confined spaces can have on the physicochemical properties of the resulting crystals and shows that CLPCs can be interesting substrates to study this process