Amin Ramezani

Bio: Amin Ramezani is an academic researcher from Tarbiat Modares University. The author has contributed to research in topics: Nonlinear system & Model predictive control. The author has an hindex of 11, co-authored 135 publications receiving 613 citations. Previous affiliations of Amin Ramezani include Shiraz University of Medical Sciences & Imam Khomeini International University.

Modulation of Cytokine Production and Transcription Factors Activities in Human Jurkat T Cells by Thymol and Carvacrol.

Abstract: Purpose: Thymol and carvacrol, two main components of thyme, have shown anti-inflammatory effects. The aim of this study was to assess the effects of these components on Jurkat leukemia cells as an in vitro T cell model and their molecular mechanisms of activity. Methods: Cells were cultured in the presence of components and subsequently stimulated with phorbol-12-myristate-13-acetate (PMA)/calcium ionophore for evaluating interleukin (IL)-2 and interferon (IFN)-γ production. The activation of T cell transcription factors that included nuclear factors of activated T cells (NFATs), activator protein-1 (AP-1; c-Jun/c-Fos), and nuclear factor (NF)-KB were examined by Western blot analysis. Results: Thymol and carvacrol at 25 µg/ml significantly reduced IL-2 levels from 119.4 ± 8pg/ml in control cells treated only with PMA/Calcium ionophore and the solvent to 66.9 ± 6.4pg/ml (thymol) and 32.3 ± 3.6pg/ml (carvacrol) and IFN-γ from 423.7 ± 19.7pg/ml in control cells to 311.9 ± 11.6pg/ml (thymol) and 293.5 ± 16.7pg/ml (carvacrol). Western blot analyses of nuclear extracts showed that the same concentrations of components significantly reduced NFAT-2 to 44.2 ± 2.7% (thymol) and 91.4 ± 2.3% (carvacrol) of the control (p<0.05), and c-Fos to 31.2 ± 6.2% (thymol) and 27.6 ± 3.1% (carvacrol) of the control (p<0.01). No effects on NFAT-1, c-Jun and phospho-NF-KBp65 levels were observed. Conclusion: Thymol and carvacrol could contribute to modulation of T cell activity by reducing IL-2 and IFN-γ production possibly through down regulation of AP-1 and NFAT-2 transcription factors suggesting their potential usefulness for reduction of T cell overactivity in immune-mediated diseases.

Quantitative expression analysis of TaSOS1 and TaSOS4 genes in cultivated and wild wheat plants under salt stress.

Abstract: Salt stress is a mixture of ionic, osmotic, and oxidative stresses. The expression of TaSOS1 (a transmembrane Na+/H+ antiporter) and TaSOS4 [a cytoplasmic pyridoxal (PL) kinase] genes were measured in four different salinity levels and different time courses of salinity exposure using qRT-PCR technique. Mahuti (salt tolerant) and Alamut (salt sensitive) cultivars were used as cultivated wheat, and T. boeticum and Aegilops crassa as wild wheat plants. Salt-induced expression of TaSOS1 in these wild wheat plants indicates the presence of active TaSOS1 gene on the genomes A and D. The TaSOS1 and TaSOS4 transcript levels were found to be downregulated after salt treatment in all cultivars except in A. crassa, which was in contrast with its expression pattern in roots that was being upregulated from a very low-basal expression, after salt treatments. Duncan’s Multiple Range Test showed a significant difference between expression in the 200-mM NaCl concentration with the 50 and 100 mM for the TaSOS1 gene, and no significant difference for TaSOS4. Lack of significant correlation between the TaSOS1 and TaSOS4 gene expressions confirms the theory that PLP has no significant effect on the expression of the TaSOS1 gene in wheat leaves.

Hypothalamic Expression of KiSS1 and RFamide-related Peptide-3 mRNAs during The Estrous Cycle of Rats.

Abstract: Kisspeptin and RFamide-related peptide-3 (RFRP-3) are known to affect GnRH/luteinizing hormone (LH) in several species, including the rat. It has been hypothesized that GnRH/LH changes during the rat estrous cycle may result from changes in the expression of KiSS1 and RFRP-3 genes. Therefore, the present study investigates KiSS1 and RFRP-3 gene expression at the transcriptional level in the rat hypothalamus during the estrous cycle. In the present experimental study, 36 adult female Sprague-Dawley rats (3-4 months old) were used to study the expression of KiSS1 and RFRP-3 mRNA in the hypothalamus during the estrous cycle. Four rats were ovariectomized, whereas the remainder were allotted to four different phases of the estrous cycle (n=8 per estrus phase). Rats were decapitated, and the hypothalami were immediately dissected and frozen in liquid nitrogen. Expressions of KiSS1 and RFRP-3 mRNAs were analyzed by real-time PCR. The expression of KiSS1 mRNA during estrus was lower than other phases of the cycle (p<0.01). Expression of KiSS1 mRNA during the metestrus phase was lower than the proestrus phase (p<0.01). The expression of RFRP-3 mRNA during proestrus was lower than the diestrus phase (p<0.01). Results of the present study showed the role of coordinated expression of KiSS1 and RFRP-3 mRNA in the hypothalamus in the control of the rat estrous cycle.

Selective Cytotoxicity and Apoptosis-Induction of Cyrtopodion scabrum Extract Against Digestive Cancer Cell Lines

Abstract: Background: Cancer is one of the major threatening factors of human health worldwide. Unfortunately, chemotherapy, the powerful arm of cancer therapy, is accompanied with many side effects, so alternative treatments with greater specificities and fewer side effects are highly required. Methods: Human cancer cell lines including SW-742, HCT116, HepG2, Hep2, MKN45 and LNcap were selected and the anti-cancer potential of Cyrtopodion scabrum extract (CsE) on their growth was studied. Vero cells were used to study the potential cytotoxicity on the normal cells. Cell cycle analysis and DNA fragmentation assay were also performed. Results: CsE was toxic (30% - 78%) to all the cell lines, with the highest cytotoxicity on SW742, MKN45 and HepG2, respectively. A high selectivity index (> 2) was observed for the extract on SW742 and MKN45 cell lines. DNA laddering pattern, as well as a significant increase in the number of the cells accumulated in sub-G1 and G2-phase of the cell cycle compared to the control untreated cells, was also observed. Conclusions: CsE suppressed the human cancer cells selectively and probably through apoptosis and G2 arrest mechanism. It could suggest a promising alternative/complementary treatment for cancer patients, especially those who suffer from digestive tract cancer.

Adaptive Control

Abstract: This book, written by two major figures in adaptive control, provides a wealth of material for researchers, practitioners, and students. While some researchers in adaptive control may note the absence of a particular topic, the book‘s scope represents a high-gain instrument. It can be used by designers of control systems to enhance their work through the information on many new theoretical developments, and can be used by mathematical control theory specialists to adapt their research to practical needs. The book is strongly recommended to anyone interested in adaptive control.

L2 Gain And Passivity Techniques In Nonlinear Control

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Species Variation in the Mechanisms of Mesenchymal Stem Cell-Mediated Immunosuppression

Abstract: Bone marrow‐derived mesenchymal stem cells (MSCs) hold great promise for treating immune disorders because of their immunoregulatory capacity, but the mechanism remains controversial. As we show here, the mechanism of MSC‐mediated immunosuppression varies among different species. Immunosuppression by human‐ or monkey‐derived MSCs is mediated by indoleamine 2,3‐dioxygenase (IDO), whereas mouse MSCs utilize nitric oxide, under the same culture conditions. When the expression of IDO and inducible nitric oxide synthase (iNOS) were examined in human and mouse MSCs after stimulation with their respective inflammatory cytokines, we found that human MSCs expressed extremely high levels of IDO, and very low levels of iNOS, whereas mouse MSCs expressed abundant iNOS and very little IDO. Immunosuppression by human MSCs was not intrinsic, but was induced by inflammatory cytokines and was chemokine‐dependent, as it is in mouse. These findings provide critical information about the immunosuppression of MSCs and for better application of MSCs in treating immune disorders. STEM CELLS 2009;27:1954–1962