Chemical modification of acellular fish skin as a promising biological scaffold by carbodiimide cross-linker for wound healing

Biological matrices can be modified with cross-linkers to improve some of their characteristics as scaffolds for tissue engineering. In this study, chemical cross-linker 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) was used with different ratios (5, 10, 20, 30, and 40 mM) to improve properties such as mechanical strength, denaturation temperature, and degradability of the acellular fish skin as a biological scaffold for tissue engineering applications. Morphological analysis showed that the use of cross-linker at low concentrations had no effect on the structure and textiles of the scaffold, while increasing mechanical strength, denaturation temperature, and degradation time. Cytotoxicity and cellular studies showed that the optimal cross-linker concentration did not significantly affect cell viability as well as cell adhesion. In general, utilising the carbodiimide cross-linker with the optimal ratio can improve the characteristics and function of the biological tissues such as acellular fish skin.     

Atlas-based fiber bundle segmentation using principal diffusion directions and spherical harmonic coefficients

PurposeTo develop an automatic atlas-based method for segmentation of fiber bundles using High Angular Resolution Diffusion Imaging (HARDI) data.HypothesisQuantitative evaluation of diffusion characteristics inside specific fiber bundles provides new insights into disease developments, evolutions, therapy effects, and surgical interventions.BackgroundMost of previous segmentation methods use similarity measures and strategies that do not lead to accurate segmentation results. They also suffer from subjectivity of initial seeds and regions of interest (ROI) defined by operator.Materials and methodsWe propose a novel method that uses Spherical Harmonic Coefficients (SHC) of HARDI diffusion signals to compute Orientation Distribution Function (ODF) and to extract Principal Diffusion Directions (PDDs). The proposed method selects most collinear PDD of neighbors of each voxel. Then, based on SHC and selected PDD, a similarity measure is proposed and used as a speed function in the level set framework that segments fiber bundles. To automate the process, an atlas-based method is used to select initial seeds for fiber bundles. To generate data for evaluation of the proposed method, an artificial pattern consisting of three crossing bundles intersected by a circular bundle is created. Also, two normal controls are imaged by two different HARDI protocols.ResultsSegmentation results for different fiber bundles in simulated data and normal control data are presented. Influence of threshold selection on the proposed segmentation method is evaluated using Dice coefficient. Also, effect of increasing the number of gradient directions on accuracy of extracted PDDs is evaluated.ConclusionThe proposed segmentation method has advantages over previous methods especially those that use similarity measures based on diffusion tensor imaging (DTI) data. These advantages are achieved by proper propagation of a hyper-surface in fiber crossing areas without making assumptions about diffusivity profile and selection of initial seeds or ROI.     

Parity and breastfeeding are preventive measures against breast cancer in Iranian women

Background  

Breast cancer (BC) is the most prevalent cancer in Iranian women and the fifth most common cause of cancer-related death in Iran. Among predicting factors and preventive measures for BC, the parity and breastfeeding (BF) are controversial issues. We therefore conducted this case–control study to find out the relation of parity and BF to incidence and risk of BC.     

Effect of nickel on the mineralization of hydrocarbons by indigenous microbiota in Kuwait soils

Assessment of nickel contents in soil samples in Kuwait indicated only a minor difference in concentration in hydrocarbon‐contaminated (86 mg kg^–1 soil) and non‐contaminated soils (84 mg kg^–1 soil). The potential inhibitory effects of nickel on the number of hydrocarbon degraders, and hydrocarbon utilization were investigated over a wide range of nickel concentrations to span concentrations observed in the soil. Nickel addition, as nickel sulphate, to soil samples reduced the number of hydrocarbon degraders in all samples by a wide range (15–96%) depending on concentration and the hydrocarbon substrate utilized. Similarly, the metabolic activities were affected as observed in mineralization (3–60%) of soils amended with various concentrations of nickel. The inhibitive effects of nickel on hexadecane and crude oil utilization were minimal but were significantly higher with naphthalene (P < 0.05) in both hydrocarbon‐contaminated and non‐contaminated soils. Polarographic determination of hydrocarbons induced oxygen uptake rate demonstrated the tendency of nickel to significantly inhibit (P < 0.05) the oxidation of polyaromatic hydrocarbons compared to aliphatic hydrocarbons. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The effect of a leucite-containing ceramic filler on the abrasive wear of dental composites.

OBJECTIVES: The aim of this study was to evaluate abrasive wear of a dental composite based on a leucite-containing (KAlSi2O2 ceramic filler, and to compare it with the wear of a composite based on commonly used aluminum barium silicate glass filler. METHODS: IPS Empress (Ivoclar-Vivadent) ingots were ball milled, passed through an 800 mesh (ASTM) sieve, and used as the leucite ceramic filler. Experimental composites were prepared by mixing the silane-treated fillers with the resin monomers. The resin consisted of 70 wt% Bis-GMA and 30 wt% TEGDMA containing camphorquinone and DMAEMA as the photoinitiator system. Glass-based composites were also prepared using silane-treated aluminum barium silicate glass fillers and the same resin system. TetricCeram, a commercially available dental composite, was used as control. Spherical specimens of the composites were then prepared and kept in water for 2 weeks to reach equilibrium with water. An abrasive wear test was performed using a device designed in our laboratory and weight loss of the specimens was measured as an abrasion parameter after each 50 h. SEMs were taken from worn and fractured surfaces. Degree-of-conversion of the composites was measured using FTIR spectroscopy. Vickers surface microhardness, flexural strength, and flexural modulus of the composites were also measured. The data were analyzed and compared using ANOVA and Tukey HSD tests (significance level=0.05). RESULTS: The results showed that there were significant differences among the abrasive wear of the composites (p<0.05). The ranking from least to most was as: leucite-based composite相似文献   

Trunk movement in Parkinson's disease during rising from seated position.

Parkinson's disease (PD) is associated with particular difficulties rising from a seated position. Little is known about the mechanisms of sit-to-stand in this condition. We sought to define trunk movement during sit-to-stand in a group of patients with PD. Six patients and seven normal volunteers were studied using a six camera ELITE motion analysis system (BTS, Milan, Italy), which permitted data collection in the coronal, sagittal, and transverse planes. Retroreflective markers were positioned along the spine at C7, T3, T6, T9, T12, L3, and the sacrum. Whole-trunk kinematics and the movement at the six different trunk markers were recorded during rising. PD patients have a significantly greater degree of trunk flexion than controls, showing a significant increase in angular velocity of the trunk in the sagittal plane. The total range of movement of trunk rotation was significantly smaller in the PD group, but lateral movement in the trunk was greater than normal. These data suggest that patients with early PD compensate for their difficulties rising from a chair by generating greater trunk flexion at higher angular velocity, thus developing greater forward momentum. This process results in a decrease in the duration of the unstable transitional phase of sit-to-stand, allowing PD patients to reach the upright position as easily and safely as possible. Small rotational movements are an effective way to maintain the centre of mass within the base of support during sit-to-stand. This mechanism appears to be denied to the PD patients who may use increased movements in the coronal plane as an alternative strategy.     

miR-219 overexpressing oligodendrocyte progenitor cells for treating compression spinal cord injury

Oligodendrocyte progenitor cells (OPCs) transplantation has been considered a promising treatment for spinal cord injury, according to previous studies. Recent research shed light on the importance of microRNA 219 (miR-219) in oligodendrocyte development, so here miR-219-overexpressing OPCs (miR-219 OPCs) were transplanted in animal models of spinal cord injury to evaluate the impact of miR-219 on oligodendrocyte differentiation and functional recovery in vivo. Our findings demonstrate that transplanted cells were distributed in the tissue sections and contributed to reducing the size of cavity in the injury site. Interestingly, miR-219 promoted OPC differentiation into mature oligodendrocyte expressing MBP in vivo whereas in absence of miR-219, less number of cells differentiated into mature oligodendrocytes. An eight week evaluation using the Basso Beattie Bresnahan (BBB) locomotor test confirmed improvement in functional recovery of hind limbs. Overall, this study demonstrated that miR-219 promoted differentiation and maturation of OPCs after transplantation and can be used in cell therapy of spinal cord injury.

     

How cytosolic compartments play safeguard functions against neuroinflammation and cell death in cerebral ischemia

Ischemic stroke is the second leading cause of mortality and disability globally. Neuronal damage following ischemic stroke is rapid and irreversible, and eventually results in neuronal death. In addition to activation of cell death signaling, neuroinflammation is also considered as another pathogenesis that can occur within hours after cerebral ischemia. Under physiological conditions, subcellular organelles play a substantial role in neuronal functionality and viability. However, their functions can be remarkably perturbed under neurological disorders, particularly cerebral ischemia. Therefore, their biochemical and structural response has a determining role in the sequel of neuronal cells and the progression of disease. However, their effects on cell death and neuroinflammation, as major underlying mechanisms of ischemic stroke, are still not understood. This review aims to provide a comprehensive overview of the contribution of each organelle on these pathological processes after ischemic stroke.

     

Dual burden of body weight among Iranian children and adolescents in 2003 and 2010: the CASPIAN-III study

Introduction

Our aim was to compare changes of body mass index (BMI) and waist circumference (WC) curves of Iranian children by comparing the results of two national surveys of a surveillance program, i.e. CASPIAN-I (2003–2004) and CASPIAN-III (2009–2010). The second objective was to evaluate the prevalence of obesity, overweight and underweight among 10–18-year-old Iranian children and adolescents.

Material and methods

This study was performed among students who were selected by multistage random cluster sampling from urban and rural areas of 27 provinces of Iran, as part of a national survey of school student high risk behavior entitled CASPIAN-III, conducted in 2009–2010.

Results

We evaluated 5088 school students (50.2% boys). In rural areas, underweight was more common in boys and overweight and obesity in girls. In urban areas underweight and obesity were more common in boys, whereas overweight was more common in girls. The highest prevalence of underweight (23.5%) was seen in students aged 13 years and the lowest (11.4%) in those aged 18 years. Underweight was significantly more common in rural than in urban areas (22.1% vs. 15.8%, respectively, p < 0.0001) and overweight/obesity was more common in urban than in rural areas. Compared with the findings in 2003–2004, the overall prevalence of elevated body mass index (16.6%) including obesity (9.1%) and overweight (7.5%) as well as underweight (17.5%) increased from 2003 to 2010.

Conclusions

In recent years, the double burden of nutritional disorders has increased among Iranian children and adolescents, especially in rural areas. This change may be related to epidemiologic transition, notably in terms of nutrition transition and rapid changes in lifestyle habits. This finding is an important issue for policy-makers for interventional preventive programs.