Introducing Dendrosomal Nanocurcumin as a Compound Capable of in vitro Eliminating Undifferentiated Stem Cells in Cell Therapy Practices.

One of the major obstacles needed to be overcome before using cell therapy for clinical purposes is the high probability of tumor formation in patients who receive the transplants, as undifferentiated stem cells (SCs) have the potential to form teratomas/teratocarcinoma in xenotransplants. In this study the ability of dendrosomal nanocurcumin (solublized curcumin using a biodegradable non-toxic nano-carrier) to affect undifferentiated/hazardous cell, and hence increasing the safety of cell therapy (particularly in diabetes type I) by mesenchymal stem cells (MSCs) was examined. The results showed that after completion of differentiation of human mesenchymal stem cells (hMSCs) into insulin producing cells (IPCs), the expression level of insulin increases, although there remains a minority of undifferentiated cells which still express nestin (gene which is expressed in progenitor stem cells of IPCs). It indicates the emergence of a heterogeneous population containing undifferentiated and differentiated cells. Furthermore our data demonstrated that the expression level of p53 decreases during differentiation of hMSCs into IPCs which implies a more favorable microenvironment for tumor formation following the transplantation of such a heterogeneous population. After treatment with dendrosomal nanocurcumin, nestin expression eliminated, however no significant effect on the expression and secretion of insulin was observed. Together our data shows that dendrosomal nanocurcumin have the ability to affect residual undifferentiated stem cells after the completion of differentiation of MSCs induced to differentiate into IPCs; while it exerts no significant harmful effect on the survival and function of differentiated cells. With regard to the obtained results in this study, exploiting dendrosomal nanocurcumin, after completion of induced differentiation of stem cells and prior to the transplantation step, can be suggested as a very efficient, safe and cost-effective method to eliminate the residual undifferentiated stem cells in cell therapy practices in order to considerably decrease the risk of tumor development following transplantation.

Effect of surface modification by nitrogen ion implantation on the electrochemical and cellular behaviors of super-elastic NiTi shape memory alloy.

The aim of this investigation was to enhance the biological behavior of NiTi shape memory alloy while preserving its super-elastic behavior in order to facilitate its compatibility for application in human body. The surfaces of NiTi samples were bombarded by three different nitrogen doses. Small-angle X-ray diffraction was employed for evaluating the generated phases on the bombarded surfaces. The electrochemical behaviors of the bare and surface-modified NiTi samples were studied in simulated body fluid (SBF) using electrochemical impedance and potentio-dynamic polarization tests. Ni ion release during a 2-month period of service in the SBF environment was evaluated using atomic absorption spectrometry. The cellular behavior of nitrogen-modified samples was studied using fibroblast cells. Furthermore, the effect of surface modification on super-elasticity was investigated by tensile test. The results showed the improvement of both corrosion and biological behaviors of the modified NiTi samples. However, no significant change in the super-elasticity was observed. Samples modified at 1.4E18 ion cm(-2) showed the highest corrosion resistance and the lowest Ni ion release.

Electrochemical and cellular behavior of ultrafine-grained titanium in vitro.

The electrochemical and cellular behavior of commercially pure titanium (CP-Ti) with both ultrafine-grained (UFG) and coarse-grained (CG) microstructure was evaluated in this study. Equal channel angular pressing was used to produce the UFG structure titanium. Polarization and electrochemical impedance tests were carried out in a simulated body fluid (SBF) at 37°C. Cellular behaviors of samples were assessed using fibroblast cells. Results of the investigations illustrate the improvement of both corrosion and biological behavior of UFG CP-Ti in comparison with the CG counterpart.

Evaluation of the effects of injection velocity and different gel concentrations on nanoparticles in hyperthermia therapy.

BACKGROUND AND OBJECTIVE: In magnetic fluid hyperthermia therapy, controlling temperature elevation and optimizing heat generation is an immense challenge in practice. The resultant heating configuration by magnetic fluid in the tumor is closely related to the dispersion of particles, frequency and intensity of magnetic field, and biological tissue properties. METHODS: In this study, to solve heat transfer equation, we used COMSOL Multiphysics and to verify the model, an experimental setup has been used.  To show the accuracy of the model, simulations have been compared with experimental results. In the second part, by using experimental results of nanoparticles distribution inside Agarose gel according to various gel concentration, 0.5%, 1%, 2%, and 4%, as well as the injection velocity, 4 µL/min, 10 µL/min, 20 µL/min, and 40 µL/min, for 0.3 cc magnetite fluid, power dissipation inside gel has been calculated and used for temperature prediction inside of the gel. RESULTS: The Outcomes demonstrated that by increasing the flow rate injection at determined concentrations, mean temperature drops. In addition, 2% concentration has a higher mean temperature than semi spherical nanoparticles distribution. CONCLUSION: The results may have implications for treatment of the tumor and any kind of cancer diseases.

The influence of torque and manual glide path on the defect or separation rate of NiTi rotary instruments in root canal therapy.

INTRODUCTION: One of the effecting factors in prognosis of root canal therapy is accidental procedure as broken files that may be unpreventable. Many manufacturers have designed and marketed various electromotors that can control rotational speed and torque. On the other hand, some studies have recommended applying a manual glide path to diminish contact area between the file and canal walls. The purpose of this study was evaluation of the effect of torque and a manual glide path on defects as separation of Nickel-titanium (NiTi) rotary files. MATERIALS AND METHODS: This ex vivo randomized controlled trial study was carried out on 160 canals of human's matured molars with mild curvature (15-338). After initial preparation of samples and checking for inclusion criteria, in first group, preparation was carried out with air-driven handpiece, and in group two, Endo IT was used as electromotor. In both groups, Mtwo files with simultaneous technique were used for preparation. Then all data were collected and analyzed with Mann Whitny, Mantel Cox, and t-test. RESULTS: No significant differences between two groups (P < 0.05) were observed. Based on survival analysis, safety probability of files after preparation of nine canals is 64% in group one and 69.9% in group two. There was no significant differences between this safety probability in two groups (P = 0.272). CONCLUSION: Usage of torque control handpiece is not an important factor, comparing instrumentation technique.