Antibacterial Activities of 5-Nitro-2-uryl and 5-Nitro-2-Imidazolyl Derivatives of 1,3,4-Thiadiazole

Introduction: Nitrofurans and nitroimidazoles are broad-spectrum antimicrobial agents, which affect the microbial DNA. The aim of the present study was to evaluate the new derivatives of these two groups of antimicrobials against certain Gram-positive and Gram-negative bacterial strains. Materials and Methods: Seven new derivatives of nitrofurans and nitroimidazoles were synthesized, and 6.4 mg of each derivative was dissolved in dimethyl sulfoxide. Then, 8 serial dilutions (0.5, 1, 2, 4, 8, 16, 32, and 64 μg/ml) of each derivative was prepared using Muller-Hinton broth, and the minimum inhibitory concentration for each derivative was measured and compared to ciprofloxacin (standard). Results: All the derivatives had no antibacterial effects against Gram-negative bacteria (minimum inhibitory concentration > 64 μg/ml); only 2-(5-nitro-2-furyl)-5-(n-pentylsulfunyl)-1,3,4-thiadiazole exhibited mild antibacterial effects against Klebsiella pneumonia (minimum inhibitory concentration of 16-32 μg/ml). The antibacterial effects of the derivatives against Gram-positive bacteria also showed variations from complete inhibition of the growth of Staphylococcus epidermidis and Bacillus subtilis (minimum inhibitory concentration < 0.5 μg/ml) by 2-(5-nitro-2-furyl)-5-(n-buthylthio)-1,3,4-thiadiazole to no inhibition of S. epidermidis and streptococcus pyogenes. Conclusion: These compounds have weak antibacterial effects; only two derivatives showed antibacterial effects similar to that of the positive control

The effect of silver nanoparticles on learning and memory in rodents: "a systematic review"

Abstract Background Silver nanoparticles (AgNPs) are widely used in medicine owing to their antiseptic activity and inducing cell death. Despite AgNPs' importance in nano-engineering and medical benefits, animal studies have shown silver toxicity can damage multiple organs such as the lungs, liver, kidneys, intestines, and brain. Several investigations revealed the correlation between Ag administration by different methods with impaired cognitive and behavioral abilities. Therefore, this systematic review aimed to conclude on the existing evidence of impairments in learning and memory that were changed in rodents exposed to AgNPs. Methods Main searches were retrieved in Google Scholar, Scopus, Web of Science, and PubMed databases from 1979 to 2022. Eligibility Criteria were applied to select and extract 15 articles among 892. Results Learning and memory abilities of rats and mice in screened studies were evaluated with MWM, NORT, PAL, T-maze, Y-maze, contextual fear conditioning, Radial Arm Maze and Carousel Maze test. Data have shown various sizes from 10 to 100 nm could affect the results of tests among animals exposed to AgNPs compared with control animals. However, in some treatments, results achieved from tests have not demonstrated significant differences between control and treated groups. Conclusion Studies have revealed that treatment with Ag-NPs of different sizes can impair learning and memory skills in rats and mice