Biophysics
Amir Sabet
Articles in Press, Accepted Manuscript, Available Online from 01 December 2013
Abstract
Nowadays the world is full of some less known species of signals which connect us together. So human beings are continually exposed to electric, magnetic and electromagnetic fields. In order to investigate the effects of magnetic fields on cell survival, bone marrow mesenchymal stem cells were exposed ...
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Nowadays the world is full of some less known species of signals which connect us together. So human beings are continually exposed to electric, magnetic and electromagnetic fields. In order to investigate the effects of magnetic fields on cell survival, bone marrow mesenchymal stem cells were exposed to 15 mT static magnetic field in the presence and the absence of 0.5 gray X-ray. The rate of dead cells didn't show a significant difference when the cells were treated with static magnetic field alone. But after an acute exposure with the ionizing radiation, the field increased the percentage of survived cells significantly and rescued a part of X-ray induced apoptotic cells. These data show that static magnetic field treatment, suppresses apoptosis and promotes survival in bone marrow stem cells of rat. Thus, magnetic fields might act as a co-mutagenic and co-carcinogenic agent with increasing the risk of tumor development by inhibiting apoptosis.
Biochemistry
Mostafa Jamalan; Majid Zeinali; Ebrahim Asadabadi
Articles in Press, Accepted Manuscript, Available Online from 01 December 2013
Abstract
Overexpression and malfunction of epidermal growth factor receptors (EGFRs) is associated with occurrence of malignancy in various tissues. Among all members of EGFRs, HER2 as an orphan receptor dimerized and activated without presence of any kind of ligands has significant role in incidence of breast ...
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Overexpression and malfunction of epidermal growth factor receptors (EGFRs) is associated with occurrence of malignancy in various tissues. Among all members of EGFRs, HER2 as an orphan receptor dimerized and activated without presence of any kind of ligands has significant role in incidence of breast cancer. Herceptin as approved therapeutic monoclonal antibody targets extracellular domain of HER2 and inhibits its dimerization and prevents induction of intracellular signaling cascades. Efficiency of point mutation which offered based on rational design approach for affinity maturation of Herceptin was investigated by 10 ns of molecular dynamic simulation. According to our results, Herceptin with mutated light chain make a more stable complex with HER2 compared to its native type. Asp92 in mutated VL of Herceptin constructs a stable salt bridge with Lys569 on HER2, which decreases the electrostatic energy between VL of Herceptin and HER2, thereby affecting RMSD values of IV-HER2 during 10 ns of MD simulation. Herceptin (VL; Tyr92Asp)-HER2 complex has lower level of total energy during allover of MD simulation compared to Herceptin-HER2 complex. Although Herceptin has high Kd of 5 nM, it has great potential to be enhanced. Our molecular modeling investigation demonstrated that affinity maturation of Herceptin through rational design could be performed via mutation of Tyr92 to Asp in VL chain of antibody. Improvement of Herceptin affinity for HER2 could increase its efficiency and result to reduction of its dose or frequency of administrations.
pharmacology
Sayeh Bidaran; Sima Nasri
Articles in Press, Accepted Manuscript, Available Online from 02 December 2013
Abstract
Introduction & Objective: Zinc is an essential element for the immune system. This element has different effects on immune system activity. On the other hand different serum Zn levels also alter normal B-cell line and T-cell line functions. The present study was carried out to assess B cell line and ...
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Introduction & Objective: Zinc is an essential element for the immune system. This element has different effects on immune system activity. On the other hand different serum Zn levels also alter normal B-cell line and T-cell line functions. The present study was carried out to assess B cell line and T cell line tolerance to low concentration Zinc Chloride In vitro studyMaterials & Methods: This experimental study was conducted at the Payame Noor University of Tehran in 2010. The B- cell line and T-cell line were exposed to 1, 5, 10, 20, 30, 40, 50, 75, 100,125, 150,175 and 200 µm (λ) of Zinc Chloride followed by incubation at 12, 24, 36, 48, 60 and 72 hrs. Viability of B- cell line (Raji) and T-cell line (molt-4) were evaluated with hemocytometer method and percentage of living cells have been considered as cellular tolerance index to cytotoxic effects of Zinc chloride. The results were analyzed by SPSS software, version 18 using T-test and Kruskal-Wallis testResults: In this study, the results showed Zinc chloride concentrations up to 40 µm (λ) at different incubation time points (12-72 hrs) had no effects on B cell line and T cell line viability( p> 0.05) With 50-200 µm (λ) concentrations, Zinc at different incubation time points(12-72 hrs)
Biophysics
AbdolJabbar Shokri; Shahryar Saeedyan; Hamed Heidari; Aram Azizi; Zohre-Sima Gilani
Abstract
Breast cancer remains a significant global health concern, necessitating the development of innovative treatment approaches. Magnetic nanoparticles (MNPs) have emerged as a promising tool in cancer therapy due to their unique properties and controllable behavior under external magnetic fields. In this ...
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Breast cancer remains a significant global health concern, necessitating the development of innovative treatment approaches. Magnetic nanoparticles (MNPs) have emerged as a promising tool in cancer therapy due to their unique properties and controllable behavior under external magnetic fields. In this paper, a two-dimensional simulation model has been used to investigate the potential of magnetic nanoparticles for breast tumor treatment. The model considers factors such as the type and size of nanoparticles, the behavior of the particles in the presence of an applied magnetic field, and the effects of MNPs on tumor tissue. Additionally, the duration of time that nanoparticles are exposed to alternating electromagnetic fields was modeled using the finite element method and Comsol Multiphysics software package. The calculation results demonstrate that the extent of tumor and healthy tissue destruction depends on the type of nanoparticles. Furthermore, an increase in the diameter of nanoparticles leads to a decrease in the percentage of tumor tissue destruction. It is important to note that increasing the amount of heating only results in more destruction of healthy tissues, thus the most significant destruction occurred within 50 minutes.
