Development of a synthetic tissue engineered three‐dimensional printed bioceramic‐based bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro

Over the last decade there have been increasing efforts to develop three‐dimensional (3D) scaffolds for bone tissue engineering from bioactive ceramics with 3D printing emerging as a promising technology. The overall objective of the present study was to generate a tissue engineered synthetic bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro, thereby mimicking the advantageous properties of autogenous bone grafts and facilitating usage for reconstructing segmental discontinuity defects in vivo. To this end, 3D scaffolds were developed from a silica‐containing calcium alkali orthophosphate, using, first, a replica technique – the Schwartzwalder–Somers method – and, second, 3D printing, (i.e. rapid prototyping). The mechanical and physical scaffold properties and their potential to facilitate homogenous colonization by osteogenic cells and extracellular bone matrix formation throughout the porous scaffold architecture were examined. Osteoblastic cells were dynamically cultured for 7 days on both scaffold types with two different concentrations of 1.5 and 3 × 10⁹ cells/l. The amount of cells and bone matrix formed and osteogenic marker expression were evaluated using hard tissue histology, immunohistochemical and histomorphometric analysis. 3D‐printed scaffolds (RPS) exhibited more micropores, greater compressive strength and silica release. RPS seeded with 3 × 10⁹ cells/l displayed greatest cell and extracellular matrix formation, mineralization and osteocalcin expression. In conclusion, RPS displayed superior mechanical and biological properties and facilitated generating a tissue engineered synthetic bone graft in vitro, which mimics the advantageous properties of autogenous bone grafts, by containing homogenously distributed terminally differentiated osteoblasts and mineralizing bone matrix and therefore is suitable for subsequent in vivo implantation for regenerating segmental discontinuity bone defects. Copyright © 2016 John Wiley & Sons, Ltd.     

Quadriceps force production during straight leg raising at different hip positions with and without concomitant ankle dorsiflexion

Objective

Due to the significant prevalence of knee disorders and patellofemoral pain syndrome, as well as the importance of quadriceps strengthening in knee rehabilitation programs, it is necessary to specify the best method to activate and strengthen the quadriceps muscles. The current study aimed at comparing the maximum generated isometric force during an active straight-leg-raising (SLR) maneuver in a sitting position by changing the hip rotational position with and without the simultaneous contraction of the ankle dorsiflexor muscles.

Estimation of biophysical parameters in wheat crops in Golestan province using ultra-high resolution images

Due to various factors which impress wheat growth variability, we need short–term monitoring of biophysical parameters using ultra–high resolution images. These provide an ability to monitor crops at the individual plant level. Two flight missions were carried out at altitude of 40 m with a commercial quad copter and a commercial camera. The images were taken before and after tillage over an 8.8 ha field. The 2 cm orthoimages and surface models were generated using photogrammetric software. Then, the image variables including ratio of the blue and green band, ratio of the red and blue band,ratio of the red and green band, plant height were extracted from orthoimages and surface models. Field measurement included the leaf area index, plant height and biomass for 15 plots each of area 1 m × 1 m. Due to a linear relationship between the biophysical parameters and image variables, it was used a multivariate regression model for modelling. The model using the image variables resulted in coefficient of determination (R²) of 0.95 and the lowest error measures (RMSE = 0.24). The results show that ultra–high resolution images can be used for monitoring of biophysical parameters in wheat crops but it is limited for large area.     

Effects of melatonin supplementation on disease activity,oxidative stress,inflammatory, and metabolic parameters in patients with rheumatoid arthritis: a randomized double-blind placebo-controlled trial

Clinical Rheumatology - Considering the pathologic significance of inflammation and oxidative stress in rheumatoid arthritis (RA) as well as the antioxidant, anti-inflammatory and hypolipidemic...     

Update on the efficacy of statins in primary and secondary prevention of atrial fibrillation

Atrial fibrillation is the most common arrhythmia in adults and its prevalence is growing rapidly. It has been shown that AF is associated with increased risk of heart failure, ischemic and hemorrhagic stroke, and mortality. Hence, there is growing interest among researchers in seeking preventive and therapeutic interventions regarding AF. In recent decades, it has been suggested that statins may decrease the incidence of AF and may also decrease its recurrence after cardioversion and catheter ablation. These effects are thought to be mediated by different mechanisms such as modulating inflammation, altering the properties of transmembrane ion channels, interfering with activation of matrix metalloproteinases, and acting on endothelial function. In this article, we review and update current knowledge about the role of statins in primary and secondary prevention of AF in general and specific populations.     

Administration of Selenium Nanoparticles Reverses Streptozotocin-Induced Neurotoxicity in the male rats

Metabolic Brain Disease - Alzheimer’s disease is the most common neurodegenerative disease associated with deposition of amyloid-beta and the increased oxidative stress. High free radical...