Electrochemically reduced graphene oxide on CoCr biomedical alloy: Characterization, macrophage biocompatibility and hemocompatibility in rats with graphene and graphene oxide.

Electrochemically reduced graphene oxide (ErGO) films on a biomedical grade CoCr alloy have been generated and characterized in order to study their possible application for use on joint prostheses. The electrodeposition process was performed by cyclic voltammetry. The characterization of the ErGO films on CoCr alloys by XPS revealed sp2 bonding and the presence of CO and CO residual groups in the graphene network. Biocompatibility studies were performed with mouse macrophages J774A.1 cell cultures measured by the ratio between lactate dehydrogenase and mitochondrial activities. An enhancement in the biocompatibility of the CoCr with the ErGO films was obtained, a result that became more evident as exposure time increased. Macrophages on the CoCr with the ErGO were well-distributed and conserved the characteristic cell shape. In addition, vimentin expression was unaltered in comparison with the control, results that indicated an improvement in the CoCr biocompatibility with the ErGO on the material surface. The in vivo response of graphene and graphene oxide was assessed by intraperitoneal injection in wistar rats. Red blood cells are one of the primary interaction sites so hemocompatibility tests were carried out. Rats inoculated with graphene and graphene oxide showed red blood cells of smaller size with a high content in hemoglobin.

Densitometric analysis of the human ulna / Análisis densitométrico de la ulna humana

This study describes the distribution of the normal bone mass in the mature human ulna, as knowledge of distribution may provide information to orthopaedic surgeons for the treatment of such fractures while advancing the understanding of the responses of osteosynthesis elements during bone repair. A random sample of 41 dry ulnas was studied with a DXA system using a Norland XR-26 densitometer. Two projections were performed, lateral and antero-posterior. In both projections five regions of interest (ROI) were selected: proximal (ROI 1), proximal-intermediate (ROI 2), intermediate (ROI 3), distal-intermediate (ROI 4) and distal (ROI 5). All statistical calculations were performed using Stat graphics Plus (version 5.1) and SPSS (version 15.0). Bone mineral density (BMD) and bone mineral content (BMC) were calculated. Paired data were analysed using parametric Student t-Test to compare BMD and BMC in every region in both projections. DXA show that the higher BMD is in the proximal-intermediate region (ROI 2). The higher BMC is found in the proximal region (ROI 1). Lower BMD and BMC are found in the distal region (ROI 5). The total BMD shows significant statistical differences (p0.001), which indicates the heterogeneous nature of the distribution of bone mass in the studied bone. Bone densitometry, measured by the DXA technique, is useful for assessing trabecular architecture of the human ulna.

Este estudio describe la distribución de la masa ósea de la ulna humana madura. Su conocimiento de distribución puede proporcionar información a cirujanos ortopédicos para el tratamiento de fracturas a la vez que se avanza en la comprensión de las respuestas de los elementos de osteosíntesis durante la reparación ósea. Se utilizó una muestra de 41 ulnas secas, que se estudiaron mediante absorciometría dual fotónica de rayos-X (DXA) con un densitómetro Norland XR-26. Se emplearon dos proyecciones: anteroposterior y lateral. En ambas proyecciones se seleccionaron cinco regiones de interés: proximal (ROI 1), intermedio-proximal (ROI 2), intermedia (ROI 3), intermedio-distal (ROI 4) y distal (ROI 5). Los cálculos estadísticos se realizaron con los programas Stat Graphics Plus (versión 5.1) y SPSS (versión 15.0). Se obtuvieron los valores medios y desviaciones estándar de la densidad mineral ósea (DMO) y el contenido mineral óseo (CMO) en cada una de las regiones de interés y en ambas proyecciones. Se compararon los valores medios de todas las regiones usando la prueba t de Student para muestras pareadas. La mayor DMO se encontró en la región intermedio-proximal (ROI 2) y en ambas proyecciones, mientras que la región que presentaba el mayor CMO fue la región proximal (ROI 1). Los valores más bajos, tanto de CMO como de DMO, en las dos posiciones del examen, correspondieron con la región distal (ROI 5). Al comparar cada una de las regiones con todas las restantes, encontramos que la DMO y el CMO muestran diferencias muy significativas (p0,001), lo que indica la naturaleza heterogénea de la distribución de la masa ósea en la ulna. La densitometría ósea mediante DXA es útil para establecer un esquema de construcción estructural de la ulna humana.

Total and regional bone mineral content in healthy Spanish subjects by dual-energy X-ray absorptiometry.

DESIGN: This is an observational cross-sectional study. OBJECTIVE: The aim of the present study was to describe and analyze patterns of change in total and regional bone mineral content in relation to age and gender in a sedentary Spanish sample population (from the Community of Madrid). The age range of the sample population was from birth to 80 years. MATERIALS AND METHODS: One thousand one hundred twenty healthy subjects were recruited and divided into 16 groups according to age. Each subject underwent whole-body densitometry using dual-energy X-ray absorptiometry. An analysis was made of the amount of bone mineral content (BMC) in the whole body and in different regions: the head, trunk, upper limbs, and lower limbs. RESULTS: Gender differences in mean values for upper limbs and lower limbs are statistically significant between 16 and 70 years of age. For the head and trunk, the mean BMC values show the most significant gender differences between 16 and 25 years of age (p