Introduction:

Antibiotic resistance has been a major health problem in recent years, which has led to a failure in the treatment of infectious diseases. Therefore, research to synthesize compounds that have antibiotic activity is very valuable. In present study four novel compounds (6a-d), derivatives of dichloroimidazole conjugated with triazole, were synthesized in order to obtain new bacterial efflux pump inhibitors (EPIs).

Methods and Results:

The derivatives were evaluated for their effects on the minimum inhibitory concentration (MIC) of ciprofloxacin against a methicillin and ciprofloxacin resistant Staphylococcus aureus (MCRSA) clinical isolate. Based on broth microdilution method assay, four derivatives at a minimum effective concentration (MEC) fortified the antibacterial efficacy of ciprofloxacin against MCRSA. MIC of ciprofloxacin decreased in the presence of novel compounds compared to ciprofloxacin alone between 2 to 64 fold. These compounds were then evaluated for their potency as efflux pump inhibitors using a fluorometric assay. Results indicated an increase in accumulation of ethidium bromide (a known fluorescent substrate for the NorA pump) in the presence of each compound, like verapamil (a typical inhibitor of efflux pump), thus these compounds acted as inhibitors of the NorA pump. Moreover, the MTT assay confirmed that novel compounds did not demonstrate any cytotoxic effect against three cancer cell lines, HT-29, MCF-7 and Caco-2, and a normal mouse fibroblastic cell line, NIH-3T3.

Conclusion:

Collectively, our results propose these derivatives as therapeutic options in combination therapies to tackle antibiotic resistance.

Grants: This research has been supported by Grant Number 94-02-33-29506 from Deputy of Research, Tehran University of Medical Science.

Introduction:

Streptokinase (SK) is used for thrombolytic therapy of acute myocardial infarction. Recombinant fermentation is the most common and cost-effective procedure in the production SK. Nutrients composition, as well as such fermentation variables as temperature and pH, can affect the production level of protein-based drugs expressed in E. coli. In the present study, optimized recombinant streptokinase (r-SK) production in E. coli in the form of inclusion body (IB), the effect of induction temperature and extracellular pH were evaluated.

To maximize the expression level of r-SK three different induction temperatures were used to obtain the optimal temperature for r-SK production. The effect of extracellular pH on the level of r-SK production was also studied and the optimal pH was determined. To this purpose, 8 fermentation processes were applied and followed by: Cell disruption, Isolation of IBs, determination of target protein (SDS-PAGE, Western-blot). The biological activity of r-SK obtained from optimal conditions was determined in comparison with reference standard using gel clot method.

The highest amount of expression level and IBs formation were performed by combining two temperatures: 42˚C for the first two hours of induction followed by 39˚C at pH 6. The expression level of r-SK under these conditions shows an 11.6% increase in comparison with the control.

Conclusions:

Choosing appropriate cultivation conditions can increase IB formation and use its advantages to produce higher quantities of r-SK with appropriate biological activity.

Introduction: Cell Culture is a simple and accurate way to evaluate the effect of various factors on different cell lines. One of the most important factors in cell culture is selection of the right cell line for different experiments which might dramatically affect our final conclusions. The purpose of this study was to examine the importance of cell line selection in cellular survival assays.

Methods and Results: To reach this purpose, we used four different cell lines, A2780, A549, HT29 and MIA paca-2, and three widely used pharmaceuticals chemicals. MTT assay was performed in order to evaluate the effect of cisplatin, dexamethasone and progesterone on cell survival after 24 hours exposure. Dexamethasone has proliferation effects on A549, no significant effect on A2780 and MIA paca-2 cell lines, and cytotoxic in high concentrations for HT29 cells. Higher concentrations of progesterone has cytotoxic effect on all four cell lines, furthermore low concentrations of progesterone has proliferative effect on A2780. On the other hand, it did not show any significant effect on A549, HT29 and MIA paca-2 cells in lower concentrations. Cisplatin has cytotoxic effect on all four cell lines with different EC₅₀s.

Conclusions: The results of this study revealed that choosing the proper cell line is important for gaining the reliable results in cell culture experiments. 

COX-2 inhibitory activities of some thiazinan, benzdiazinan and benzthiazinan derivatives were modeled by quantitative structure–activity relationship (QSAR) with stepwise-multiple linear regression (SW-MLR) method. The built model was robust and predictive with correlation coefficient (R²) of 0.840 for training and 0.522 for test groups. The quality of the model was evaluated by leave-one out (LOO) cross validation and LOO correlation coefficient (Q²) was 0.639. We also investigated a leverage approach for defining of applicability domain of model. According to QSAR model results, COX-2 inhibitory activity of selected data set had correlation with VE3_Dzm (Logarithmic coefficient sum of the last eigenvector from Barysz matrix weighted by mass), GATS6c (geometrical structure of the considered molecules in a complex way) and GATS5i (Geary autocorrelation of lag 5 weighted by ionization potential) descriptors which derived from their structures.

Introduction:

Tacrolimus, an immunosuppressive agent, has been shown to be an effective treatment against corneal neovascularization (CNV). However, the poor solubility of this compound restricts its clinical application. The goal of this study was to incorporate tacrolimus into phospholipid-bile salt mixed micelles.

Methods and Results:

Tacrolimus loaded phospholipid-bile salt mixed micelles were prepared, employing three different methods of direct dispersion, thin film hydration, and remote film loading, and the effects of various formulation parameters (type of dispersion medium, phospholipid to bile salt molar ratio, lipid-to-drug (L/D) molar ratio, time of probe sonication, and type of bile salt) on the physicochemical characteristics of the mixed micelles were assessed. Remote film loading method indicated higher efficacy for drug entrapment in comparison to the other methods. Encapsulation of tacrolimus within the micelles increased remarkably by the use of sodium taurocholate (NaTC) as bile salt, higher phospholipid percentage, and increasing the total lipid level. Atomic force microscopy (AFM) studies confirmed the size and size distribution of the mixed micelles and their spherical morphology. It was observed that release of tacrolimus from the micelles was in a controlled manner, without an initial burst.

Conclusions:

By adjusting process and formulation factors, phospholipid-bile salt mixed micelles with high entrapment efficiency of (99.5 %) and controlled release behavior were achieved, which possess great potential to be valuable carriers for ocular delivery of tacrolimus for the treatment of CNV.                                                                                                                                        

Hepatocellular carcinoma (HCC) is the fifth most malignant of liver cancer globally. Melanoma is also a highly aggressive and deadly cancer with a poor prognosis given its drug resistance.A defect in apoptosis pathway is one of the key mechanisms that contribute to drug resistance in cancer. An important sea marine animal is the Holothuria, also known as the sea cucumber, which has various pharmacological activities. Scientists have begun to further investigate on the natural bioactive compounds found in marine animals showing anti-inflammatory and anti-cancer properties. H. sabra and H. parva, sea cucumbers are known to show the mentioned properties.

Cancerous induced animals were applied for mitochondrial investigations. The mitochondria isolated from Hepatocytes and melanoma cells via differential centrifuges was treated with various concentrations (250, 500 and 1000 µg/ml) of metanolic extract of H. parva and H. sabra. Reactive oxygen species (ROS) formation, mitochondrial swelling, mitochondrial membrane potential (MMP) and cytochrome c release resulting from the selective toxicity of various dilution of methanolic extract of H. sabra and H. parva on mitochondria isolated from cancerous induced animals were determined.

Our results show that different concentrations (250, 500 and 1000µg/ml) of themethanolicextract significantly (p<0.05) induce reactive oxygen species (ROS) formation and mitochondrial swelling, decreased mitochondrial membrane potential (MMP) disruption and increased cytochrome c release only in HCC mitochondria and melanoma mitochondria, in a time-and concentration dependent manner (In comparison to the control group).

Our study suggest that given bioactive compounds found in mentioned sea cucumbers can potentially introduced as anti-cancer molecules. Further studies such as molecular identification,  in vivo experiments and clinical trials can confirm these results.

Introduction:

Plants of the family Apiaceae are widely used in Iranian’s folk medicine, but no medicinal use of Semenovia tragioides, which is a rare plant, has been reported. Methods and Results:

The essential oil from aerial parts of Semenovia tragioides (Boiss.) Manden. (Umbelliferae) consisting mainly p-cymene (18.5 %) Z- b- ocimene (7.7%), cinnamyl isovalerate (7.4%), and g–terpinene (5.5%) was screened for antibacterial activity against six bacterial strains.

Conclusion:

The essential oil remarkably inhibited the growth of all tested bacteria (two Gram-positive and four Gram-negative). The maximum activity was against Staphylococcus aureus.