Synthesis, spectroscopic characterization, DFT studies and biological assays of a novel gold(I) complex with 2-mercaptothiazoline

A new gold(I) complex with 2-mercaptothiazoline (MTZ) with the coordination formula [AuCN(C3H5NS2)] was synthesized and characterized by chemical and spectroscopic measurements, DFT studies and biological assays. Infrared (IR) and 1H, 13C and 15N nuclear magnetic resonance (NMR) spectroscopic measurements indicate coordination of the ligand to gold(I) through the nitrogen atom. Studies based on DFT confirmed nitrogen coordination to gold(I) as a minimum of the potential energy surface with calculations of the hessians showing no imaginary frequencies. Thermal decomposition starts at temperatures near 160°C, leading to the formation of Au0 as the final residue at 1000°C. The gold(I) complex with 2-mercaptothiazoline (Au-MTZ) is soluble in dimethyl sulfoxide (DMSO), and is insoluble in water, methanol, ethanol, acetonitrile and hexane. The antibacterial activities of the Au-MTZ complex were evaluated by an antibiogram assay using the disc diffusion method. The compound showed an effective antibacterial activity against Staphylococcus aureus (Gram-positive) and Escherichia coli and Pseudomonas aeruginosa (Gram-negative) bacterial cells. Biological analysis for evaluation of the cytotoxic effect of the Au-MTZ complex was performed using HeLa cells derived from human cervical adenocarcinoma. The complex presented a potent cytotoxic activity, inducing 85% of cell death at a concentration of 2.0 μmol L-1.301323542359CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP141617/2010-12006/55367-

Pacemaker implantation after sutureless or stented valve: results from a controlled randomized trial

OBJECTIVES: Sutureless aortic valves demonstrated non-inferiority to standard stented valves for major cardiovascular and cerebral events at 1 year after aortic valve replacement. We aim to assess the factors correlating with permanent pacemaker implantation (PPI) in both cohorts.METHODS: PERSIST-AVR is a prospective, randomized, open-label trial. Patients undergoing aortic valve replacement were randomized to receive a sutureless aortic valve replacement (Su-AVR) or stented sutured bioprosthesis (SAVR). Multivariable analysis was performed to identify possible independent risk factors associated with PPI. A logistic regression analysis was performed to estimate the risk of PPI associated to different valve size.RESULTS: The 2 groups (Su-AVR; n = 450, SAVR n = 446) were well balanced in terms of preoperative risk factors. Early PPI rates were 10.4% in the Su-AVR group and 3.1% in the SAVR. PPI prevalence correlated with valve size XL (P = 0.0119) and preoperative conduction disturbances (P = 0.0079) in the Su-AVR group. No predictors were found in the SAVR cohort. Logistic regression analysis showed a significantly higher risk for PPI with size XL compared to each individual sutureless valve sizes [odds ratio (OR) 0.272 vs size S (95%confidence interval 0.07-0.95), 0.334 vs size M (95% CI 0,16-0; 68), 0.408 vs size L (95% CI 0,21-0.81)] but equivalent risk of PPI rates for all other combination of valve sizes.CONCLUSIONS: Su-AVR is associated with higher PPI rate as compared to SAVR. However, the increased PPI rate appears to be size-dependent with significant higher rate only for size XL. The combination of preoperative conduction disorder and a size XL can lead to a higher probability of early PPI in Su-AVR