Iranian Journal of Basic Medical Sciences
Year:2013 | Volume:16 | Issue:11|Papers Count:12

Epilepsy is one of the most common chronic disorders affecting individuals of all ages. A greater understanding of pathogenesis in epilepsy will likely provide the basis fundamental for development of new antiepileptic therapies that aim to prevent the epileptogenesis process or modify the progression of epilepsy in addition to treatment of epilepsy symptomatically. Therefore, several investigations have embarked on advancing knowledge of the mechanism underlying epileptogenesis, understanding in mechanism of pharmacoresistance and discovering antiepileptogenic or disease-modifying therapy. Animal models play a crucial and significant role in providing additional insight into mechanism of epileptogenesis. With the help of these models, epileptogenesis process has been demonstrated to be involved in various molecular and biological pathways or processes. Hence, this article will discuss the known and postulated mechanisms of epileptogenesis and challenges in using the animal models.

Objective (s): Nowadays, cancer is an important public health problem in all countries. Limitations of current chemotherapy for neoplastic diseases such as severe adverse reactions and tumor resistance to the chemotherapeutic drugs have been led to a temptation for focusing on the discovery and development of new compounds with potential anticancer activity.Materials and Methods: A new series of 1, 3, 4-thiadiazole-derived compounds (3a-3l) were synthesized. N - (5-Mercapto-1, 3, 4-thiadiazol-2-yl) -2- (4-methoxyphenyl) acetamide (2) was prepared through direct amidation of 4-methoxyphenylacetic acid (2) with 5-amino-1, 3, 4-thiadiazole-2-thiol using EDC (N -Ethyl- N -dimethylaminopropyl carbodiimide) and HOBt (Hydroxybenzotriazole). Then, various derivatives of benzyl chloride containing electron withdrawing and electron donating moieties were reacted with compound 2 to prepare compounds 3a-3l. In vitro cytotoxicity assessment using MTT method was applied and results are presented as IC50.Results: All the synthesized compounds were characterized by 1H-NMR and IR spectroscopy. Some of the synthesized compounds were also characterized using MS spectroscopy. Related melting points were also recorded. According to the obtained data from MTT assay, all compounds (3a-3l) demonstrated a higher cytotoxic activity against MDA-MB-231 breast cancer cell line in comparison with other cell lines.Conclusion: It is notable that four synthesized compounds 3h (IC50=11±0.18 mM), 3j (IC50=10±0.39 mM), 3k (IC50=11±0.77 mM) and 3l (IC50=8±0.69 mM) exhibited higher cytotoxic activity against MDA-MB-231 cell line compared to imatinib (IC50=20±0.69 mM) as the reference drug.

Objective (s): Snake venoms contain complex mixture of proteins with biological activities. Some of these proteins affect blood coagulation and platelet function in different ways. Snake venom toxin may serve as a starting material for drug design to combat several pathophysiological problems such as cardiovascular disorders. In the present study, purification of anticoagulation factor from venom of snake (Echis carinatus) was studied. Anticoagulation activity of crude venom, fractions and purified peptide were determined by using prothrombin time (PT) and thrombin time (TT). Three fractions were partially purified from the venom of E. Carinatus by gel filtration on sephadex G-75 and final purification was performed by high-performance liquid chromatography (HPLC) with C18 column. A purified anticoagulant factor was derived which showed a single protein band in SDS-PAGE electrophoresis under reducing condition. Results of PT and TT tests for purified peptide (EC217) were found to be 102±4.242 and<5 min. respectively. Determination of molecular weight revealed that the active purified peptide (EC217) was about 30 KD. In conclusion, the present study showed that the venom of E. carinatus contains at least one anticoagulant factor.

Objective (s): Echis carinatus is one of the venomous snakes in Iran. The venom of Iranian Echis carinatus is a rich source of protein with various factors affecting the plasma protein and blood coagulation factor. Some of these proteins exhibit types of enzymatic activities. However, other items are proteins with no enzymatic activity.Materials and Methods: In order to study the mechanism and effect of the venom on human plasma proteins, the present study has evaluated the effect of crude venom and all fractions. A procoagulant factor (prothrombin activator) was isolated from the venom of the Iranian snake Echis carinatus with a combination of gel filtration (Sephadex G-75), ion-exchange chromatography (DEAE- Sepharose) and reverse phase HPLC. Furthermore, proteolytic activity of the crude venom and all fractions on blood coagulation factors such as prothrombin time (PT) was studied.Results: In the present study, the PT test was reduced from 13.4 s to 8.6 s when human plasma was treated with crude venom (concentraion of venom was 1 mg/ml). The purified procoagulant factor revealed a single protein band in SDS polyacrylamide electrophoresis under reducing conditions and its molecular weight was estimated at about 65 kDa. A single-band protein showed fragment patterns similar to those generated by the group A prothrombin activators, which convert prothrombin into meizothrombin independent of the prothrombinase complex.Conclusion: This study showed that the fraction which separated from Iranian snake Echis carinatus venom can be a prothrombin activators. It can be concluded that this fraction is a procoagulant factor.

Objective(s): Breast cancer is the most common type of cancer among women worldwide. This study investigated the expression and clinical significance of activating transcription factor 3 (ATF3) in human breast cancer and its relationship with the clinical outcome of breast cancer.Materials and Methods: ATF3 expressions were detected in 114 primary breast cancer tissues and 114 adjacent normal tissues using immunohistochemistry (IHC) assay. Categorical variables were statistically compared by chi-square or Fisher’s exact test. Survival curves were evaluated using the Kaplan-Meier method and comparisons of survival rates were tested using a Log-rank test.Results: IHC analysis showed that the positive expression of ATF3 protein was detected in breast cancer tissue with a positive ratio of 76.3%, and the positive ATF3 expression in adjacent normal breast tissue was 13.2%, which is lower than that in breast cancer tissue samples (P<0.01). Furthermore, ATF3 expression showed significant correlation with TNM stage, invasion, lymph node metastasis and number of metastatic lymph nodes (P=0.038, P=0.029, P=0.026, and P=0.039 respectively), and did not correlate with patients’ age and tumor size (P>0.05). A significant difference in overall survival rate was found between the patients with positive expression of ATF3 protein and those with negative expression (P=0.041).Conclusion: Increased ATF3 expression participate in the tumorigenesis, invasion and metastasis of breast cancer, and ATF3 may be useful as a new prognostic indicator for breast cancer patients.

Objective(s): Chalcones and their rigid analogues represent an important class of small molecules having anticancer activities. Therefore, in this study the synthesis and cytotoxic activity of new 3-benzylidenchroman-4-ones were described as rigid chalcone analogues.Materials and Methods: The reaction of resorcinol with 3-chloropropionic acid in the presence of CF3SO3H was afforded corresponding propiophenone. It was cyclized using 2M NaOH to give 7-hydroxy-4-chromanone. O -Alkylation of 7-hydroxy-4-chromanone with alkyl iodide in the presence of K2CO3 gave 7-alkoxychroman-4-one. Finally, condensation of chroman-4-one derivatives with different aldehydes afforded target compounds in good yields. The newly synthesized compounds were tested in vitro against different human cancer cell lines including K562 (human erythroleukemia), MDA-MB-231 (human breast cancer), and SK-N-MC (human neuroblastoma) cells. The cell viability was evaluated using MTT colorimetric assay.Results: Most of the compounds showed good inhibitory activity against cancer cells. Among them, compound 4a containing 7-hydroxy group on chromanone ring and 3-bromo-4-hydroxy-5-methoxy substitution pattern on benzylidene moiety was the most potent compound with IC50 values≤3.86 mg/ml. It was 6-17 times more potent than etoposide against tested cell lines.Conclusion: We described synthesis and cytotoxic activity of poly-functionalized 3-benzylidenechroman-4-ones as new chalcone-like agents. These compounds can be considered as conformationally constrained congeners of chalcones to tolerate the poly-functionalization on the core structures for further optimization.

Objective (s): Platelet-rich plasma (PRP) has recently emerged as a promising strategy in regenerative medicine due to its multiple endogenous growth factors. Little is known about the role of PRP as a promoter in chondrogenesis of human adipose derived stem cells (hADSCs). The aim of this study was to determine whether PRP may be considered as a natural and easy achievable source of growth factors to promote the chondrogenic differentiation of hADSCs in Transwell culture.Materials and Methods: Biochemical, immunohistological and molecular assays were used to evaluate the effect of different concentrations (5%, 10%, and 15%) of PRP on chondrogenic differentiation of hADSCs in Transwell culture.Results: The cells in the presence of 10% PRP produced markedly higher amounts of GAG and DNA, in comparison to the control group. PRP also increased chondrogenic markers in these cells, such as sox-9, aggrecan and collagen type II. A high expression level of collagen type X as a hypertrophic marker was observed in cartilage produced by using either PRP or TGF-b1.Conclusion: Our findings indicate that autologous PRP at an optimum concentration had beneficial effects on differentiation of hADSCs in Transwell culture. Further, in vivo studies are necessary to fully define the clinical implications of PRP.

Objective(s): In the current study, the effects of selected folk medicinal herbs were evaluated in D-galactose-induced aging in male mice.Materials and Methods: Male BALB/c mice were randomly divided into 12 groups composing sham, control, and treated groups. Aging was induced by administration of D-galactose (500 mg/kg/day for 6 weeks). A positive control group was assigned that received vitamin E (200 mg/kg/day). The extract of herbs was prepared, lyophilized, and used in this study. The herbs were administered by gavage for 4 weeks to D-galactose-aged animals at the selected doses (mg/kg/day) as follows: Zingiber officinale (250), Glycyrrhiza glabra (150), Rosmarinus officinalis (300), Peganum harmala (50), Aloe vera (150), Satureja hortensis (200), Teucrium scordium (200), Hypericum perforatum (135) and Silybum marianum (150). One group of animals was assigned as sham and not given D-galactose.Results: At the end of treatment, pro-inflammatory markers including tumor necrosis factor-a (TNF-a), interlukine-1b (IL-b), interlukine-6 (IL-6), NF-kappaB (NF-kb), total antioxidant power (TAP), thiobarbituric acid reactive substances (TBARS) as lipid peroxidation (LPO) marker and male sex hormones i.e. testosterone and dehydroepiandrosterone-sulfate (DHEA-S) were measured in the blood.Conclusion: These data for the first time indicate significant anti-aging potential of examined herbs. Results showed that D-galactose induces a significant oxidative stress and promotes proinflammatory cascade of aging while all herbs more or less recovered these changes. Among 9 herbal extracts, Silybum marianum showed the best effect in restoring aging changes.

Objective (s): In SPECT, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. Many techniques for attenuation and scatter correction have been proposed. An acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. Here, we propose new Maximum Likelihood Expectation Maximization (MLEM) formula to correct scattering and attenuating photons during reconstruction.Materials and Methods: In this work, scatters are estimated through Klein-Nishina formula in all iterations and CT images are used for accurate attenuation correction. Reconstructed images resulted from different MLEM reconstruction formula have been compared considering profile agreement, contrast, mean square error, signal-to-noise ratio, contrast-to-noise ratio and computational time.Results: The proposed formula has a good profile agreement, increased contrast, signal-to-noise (SNR) & contrast-to-noise ratio (CNR), computational time and decreased mean square error (MSE) compared with uncorrected images and/or images from conventional formula.Conclusion: In conclusion, by applying the proposed formula we were able to correct attenuation and scatter via MLEM and improve the image quality, which is a necessary step for both qualitative and quantitative SPECT images.

Objective (s): The aim of this study was to evaluate the effect of subacute administration of propylthiouracil (PTU) on gentamicin (GM) -induced nephrotoxicity in male rats.Materials and Methods: Male Wistar rats were divided into 4 experimental groups as follow: (1) Control group: isotonic saline (1 ml/kg, IP. for 18 d), (2) GM group: 100 mg/kg, IP for 8 d, (3) PTU group: PTU (10 mg/kg, IP for 18 d.) and (4) PTU+GM group: GM (100 mg/kg, IP. for 8d) and PTU (10 mg/kg, IP. for 18 d). Blood sample was taken from all animals and then the animals were sacrificed under light ether anesthesia on the day after the last injection. Sera were separated and were used to measure the urea and creatinine. Microscopic evaluation of renal injury was performed using a semiquantitative scale to evaluate the degree of tubular necrosis.Results: GM markedly increased serum urea and creatinine, as well as acute tubular necrosis (ATN), glomerular atrophy, hyaline casts formation in tubular lumen, interstitial nephritis and infiltration of inflammatory cells. PTU administration alone caused hyperemia and interstitial nephritis and infiltration of lymphocytic inflammatory cells in cortex but it had no marked effect on glomerular and tubular morphology and function. Co-administration of PTU and GM potentiates the GM-induced nephrotoxicity characterized by diffuse ATN; diffuse hyaline cast formation in lumen and infiltration of inflammatory cell in kidney tissues.Conclusion: Our data indicate that PTU potentiates GM-induced nephrotoxicity. The underlying mechanism (s) via which PTU potentiates GM renal toxicity remains to be elucidated.

Objective (s): A fast and reliable evaluation of the binding energy from a single conformation of a molecular complex is an important practical task. Artificial neural networks (ANNs) are strong tools for predicting nonlinear functions which are used in this paper to predict binding energy. We proposed a structure that obtains binding energy using physicochemical molecular descriptions of the selected drugs.Material and Methods: The set of 33 drugs with their binding energy to cyclooxygenase enzyme (COX2) in hand, from different structure groups, were considered.27 physicochemical property descriptors were calculated by standard molecular modeling. Binding energy was calculated for each compound through docking and also ANN. A multi-layer perceptron neural network was used.Results: The proposed ANN model based on selected molecular descriptors showed a high degree of correlation between binding energy observed and calculated. The final model possessed a 27-4-1 architecture and correlation coefficients for learning, validating and testing sets equaled 0.973, 0.956 and 0.950, respectively.Conclusion: Results show that docking results and ANN data have a high correlation. It was shown that ANN is a strong tool for prediction of the binding energy and thus inhibition constants for different drugs in very short periods of time.

Objective (s): Regarding the presence of many active biological constituents in Avicennia marina, the present investigation was carried out to study cytotoxic activity of crude methanol leave extract and column chromatographic fractions of A. marina against MDA-MB 231 cell line (human breast cancer cell) and HEK (Human embryonic kidney cell) line.Materials and Methods: The anticancer activity of crude methanol extract and sub-fractions were evaluated, using MTT assay. The induction of apoptosis was determined by analyzing DNA fragmentation in breast cancer cells treated with active fraction of crude methanol extract using agarose gel electrophoresis. To investigate molecular mechanism of apoptosis, gene expression levels of p53 and Bcl-2 were measured using quantitative real time PCR.Results: Fraction 10 was the most active fraction and was detected with HPLC as luteolin. The 50% cell cytotoxic concentration (CC50) of crude methanol extract and luteolin was 250 and 28 mg/ml, respectively. This fraction was found to be an apoptotic agent against MDA-MB 231 cells, which leads to causing DNA fragmentation. The mRNA expression level of Bcl-2 and p53 was significantly decreased and increased respectively in cancer cells treated by luteolin.Conclusion: The results suggested that Luteolin isolated from Avicennia marina could probably induce apoptosis on breast cancer cell line by the regulation of p53 and Bcl-2 pathways.