Combination of Dental-Capping Agents with Low Level Laser Therapy Promotes Proliferation of Stem Cells from Apical Papilla.

Background: Direct pulp capping is a vital pulp therapy, which stimulates differentiation of stem cells from apical papilla (SCAPs). SCAPs have multipotential capacity to differentiate into types of cells, contributing to the regeneration of tissues. Objective: Considering the promising effects of dental-capping materials, we aim to investigate the effect of dental dressing materials combined with laser therapy on the percentage of SCAP viability and the consequent dental regeneration capacity. Methods: We collected two immature third molar teeth and isolated SCAPs through collagenase type I enzymatic activity. Isolated SCAPs were then cultured with Dulbecco's modified Eagle's medium and α-minimum essential medium enriched with 15% and 10% fetal bovine serum, respectively. After reaching 70-80% confluency, cells were seeded in a 96-well plate and then treated with mineral trioxide aggregate (MTA), enamel matrix derivative (EMD), biodentine, and low level laser therapy (LLLT) alone and in combination for 24, 48, and 168 h. After that, cell survival rate was assessed using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. Results: We found that combination of MTA, EMD, and LLLT as well as that of biodentine, EMD, and LLLT could lead to significant increase of SCAP viability as compared with other treatment groups. Combination of MTA and biodentine with EMD could also show increased level of SCAP proliferation and viability. However, MTA and biodentine alone reduced SCAP survival rate in all time points. Conclusions: Our conclusion is that LLLT can serve as an enhancer of SCAP proliferation and differentiation rate when added to dental-capping agents such as MTA, EMD, and biodentine. Thus, LLLT combination with effective capping materials will serve as a promising option for dental tissue repair.

Combination of static magnetic field and cisplatin in order to reduce drug resistance in cancer cell lines.

Purpose: In this study, the effects of different intensities of Static Magnetic Fields (SMFs) (10, 15 and 25 mT) and different concentrations of cisplatin drug were investigated on the viability percent and IC50 of the A2780 and A2780-CP cell lines at 24, 48 and 96 h to show useful potential of SMF as a physical agent to enhance the effectiveness of common therapeutic approaches and decrease of drug resistance to cisplatin anticancer drug. Materials and methods: Magnetic field exposure was performed using a locally designed generator. The cell viability percent, IC50 and cisplatin uptake in treated cells were evaluated by MTT assay and inductively coupled plasma (ICP), respectively. Results: Increasing of concentration and time of cisplatin drug showed a noticeable decrease in viability percent in sensitive and resistant cell lines compared with control group. These decreases were more significant in resistant cells compared with sensitive cells. The obtained IC50 values for resistant were greater than the values obtained for A2780 cells. ICP analysis demonstrated an increased uptake of cisplatin after treatment for 48 and 96 h relative to untreated groups in both resistant and sensitive cells. Conclusion: Results showed that A2780 cells were more sensitive to cisplatin than A2780-CP. Studies have shown that SMF can increase the effect of cisplatin on cell viability percent and decrease the resistance of A2780-CP cells by producing large, verruca shaped structures at the surface of the cell membrane.

Genetic variation and risk of DNA damage in peripheral blood lymphocytes of Iranian formaldehyde-exposed workers.

Formaldehyde (FA) has given positive results for the genetic damage evaluated in human peripheral blood lymphocytes. Polymorphism plays a special role in the toxicity of chemicals. DNA damage in blood cells was evaluated in workers who were occupationally exposed to FA. This study tested the association of alcohol dehydrogenase III (ADH3) and manganese-superoxide dismutase (Mn-SOD) gene polymorphism, with DNA damage of peripheral blood lymphocytes. Gene polymorphisms were evaluated in 54 workers from melamine dinnerware workshops and 34 workers from dairy production workshops. The control and exposed population were matched based on age, smoking, work history and socioeconomic status. DNA damage was evaluated by alkaline comet assay in the peripheral blood lymphocytes. ADH3 and Mn-SOD genotypes were determined in all workers using polymerase chain reaction-restriction fragment length polymorphism method. DNA damage of lymphocyte cells was significantly higher ( p < 0.001) in the exposed individuals in comparison with the control population. The examinations of the exposed group had revealed significantly higher ( p < 0.01) variant of Val/Val of Mn-SOD compared to control group. In workers with ADH32-2 variant, significantly higher levels of DNA damage ( p < 0.01) were observed than the control population with the same genotype. It could be concluded that enzymes involved in the metabolism of FA and oxidative stress controlling are two important effective parameters for DNA damage of peripheral blood lymphocytes in exposed people. These results are regarded as a pioneer investigation for the management of health risks assessment.

Investigation of gene expressions in differentiated cell derived bone marrow stem cells during bone morphogenetic protein-4 treatments with Fourier transform infrared spectroscopy.

A model was set up to predict the differentiation patterns based on the data extracted from FTIR spectroscopy. For this reason, bone marrow stem cells (BMSCs) were differentiated to primordial germ cells (PGCs). Changes in cellular macromolecules in the time of 0, 24, 48, 72, and 96h of differentiation, as different steps of the differentiation procedure were investigated by using FTIR spectroscopy. Also, the expression of pluripotency (Oct-4, Nanog and c-Myc) and specific genes (Mvh, Stella and Fragilis) were investigated by real-time PCR. However, the expression of genes in five steps of differentiation was predicted by FTIR spectroscopy. FTIR spectra showed changes in the template of band intensities at different differentiation steps. There are increasing changes in the stepwise differentiation procedure for the ratio area of CH2, which is symmetric to CH2 asymmetric stretching. An ensemble of expert methods, including regression tree (RT), boosting algorithm (BA), and generalized regression neural network (GRNN), was the best method to predict the gene expression by FTIR spectroscopy. In conclusion, the model was able to distinguish the pattern of different steps from cell differentiation by using some useful features extracted from FTIR spectra.

An in vitro study of the impact of 4mT static magnetic field to modify the differentiation rate of rat bone marrow stem cells into primordial germ cells.

This investigation was performed to evaluate the differentiation capacity and alteration in genes expression patterns during in vitro differentiation of bone marrow stem cells into primordial germ cells using static magnetic field (4mT) and BMP-4 (25ng/ml). The rate of differentiation was investigated using the Real Time-PCR method for tracing expression of differentiation markers (Oct-4, Nanog, C-Myc, Fragilis, Mvh and Stella). Then, immunocytochemical reaction was carried out for detection of marker proteins (Oct4 and Mvh). Increasing of the exposure time of the 4mT SMF (24 and 48h) and treatment time with 25ng/ml BMP4 (48 and 96h) indicated a marked decrease in expression of pluripotency genes (Oct-4, Nanog and C-Myc) and Oct4 protein and increase in primordial germ cell-specific genes (Fragilis, Mvh and Stella) and Mvh protein compared with the control group. Final results showed that in a synergistic manner, the combination of SMF with BMP4 exaggerates the differentiation potential of BMSCs to PGCs by activating the MAPK pathway and altering the Ca(2+) concentration.

Oxidative stress in broad bean (Vicia faba L.) induced by static magnetic field under natural radioactivity.

The investigation was performed to evaluate the influence of the static magnetic field on oxidative stress in Vicia faba cultivated in soil from high background natural radioactivity in Iran. Soil samples were collected from Ramsar, Iran where the annual radiation absorbed dose from background radiation is substantially higher than 20 mSv/year. The soil samples were then divided into 2 separate groups including high and low natural radioactivity. The plants were continuously exposed to static magnetic field of 15 mT for 8 days, each 8h/day. The results showed that in the plants cultivated in soils with high background natural radioactivity and low background natural radioactivity the activity of antioxidant enzymes as well as flavonoid content were lower than those of the control. Treatment of plants with static magnetic field showed similar results in terms of lowering of antioxidant defense system and increase of peroxidation of membrane lipids. Accumulation of ROS also resulted in chromosomal aberration and DNA damage. This phenomenon was more pronounced when a combination of natural radiation and treatment with static magnetic field was applied. The results suggest that exposure to static magnetic field causes accumulation of reactive oxygen species in V. faba and natural radioactivity of soil exaggerates oxidative stress.

Elucidating the protein cold-adaptation: Investigation of the parameters enhancing protein psychrophilicity.

To investigate the role of the critical parameters in adaptation of proteins to low temperatures, a comparative systematic analysis was performed. Several parameters were proposed to have contribution to cold adaptation of proteins. Among proposed parameters, total values of residual structure states, secondary structure states and oligomeric states were alike in both psychrophilic and mesophilic proteins. In addition, our results provided new quantitative information about the trends in the substitution preference of Ile, Phe, Tyr, Lys, Arg, His, Glu and Leu with most of amino acids and substitution avoidance of Gly, Thr and Ala with most of amino acids. These findings would help future efforts propose a strategy for designing psychrophilic proteins.