PEGylated PAMAM dendrimers loading oxaliplatin with prolonged release and high payload without burst effect.

Oxaliplatin (OXA) was coupled to PEGylated polyamidoamine dendrimers of fourth generation (G4-PEG@OXA) in the comparison to PEGylated ones of odd generation (G3.5-PEG@OXA). Proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy were used to confirm the successful incorporation of OXA as well as the synthesis of carrier systems. Both two types of carrier systems exhibited in sphere nanoparticle shape with size of less than 100 nm that was in the range being able to cause toxicity on cancer cells. The average drug loading efficiency (DLE) of G4-PEG@OXA was obtained at 84.63% that was higher than DLE of G3.5-PEG of 75.69%. The release kinetic of G4-PEG@OXA and G3.5-PEG@OXA did not show any burst release phenomenon while free OXA was released over 40% at the first hour. The sustainable release of OXA was achieved when it was encapsulated in these carriers, but the G4 generation liberated OXA (3.4%-6.4%) slower than G3.5 one (11.9%-22.8%). The in vitro cytotoxicities of G4-PEG@OXA were evaluated in HeLa cell lines using resazurin assay and live/dead staining test. Although the free OXA showed a rather moderate killing ability, the G4-PEG@OXA still displayed the low viability of HeLa that was better to the result of G3.5-PEG@OXA due to released OXA amount. The benefit of this system was to overcome the burst release phenomenon to minimize OXA toxicity without compromising its efficiency.

Aetiology and Potential Animal Exposure in Central Nervous System Infections in Vietnam.

An estimated 73% of emerging infections are zoonotic in origin, with animal contact and encroachment on their habitats increasing the risk of spill-over events. In Vietnam, close exposure to a wide range of animals and animal products can lead to acquisition of zoonotic pathogens, a number of which cause central nervous system (CNS) infections. However, studies show the aetiology of CNS infections remains unknown in around half of cases. We used samples and data from hospitalised patients with CNS infections, enrolled into the Vietnam Initiative on Zoonotic Infections multicentre study, to determine the association between aetiology and animal contact including those in whom the cause was unknown. Among 933 patients, a pathogen or an antibody response to it was identified in 291 (31.2%, 95% CI 28.3-34.3%). The most common pathogens were Streptococcus suis (n = 91 (9.8%, 8.0-11.9%)) and Japanese encephalitis virus (JEV) (n = 72 (7.7%, 6.1-9.7%)). Commonly reported animal contact included keeping, raising or handling (n = 364 (39.0%, 35.9-42.2%)) and handling, cooking or consuming raw meat, blood or viscera in the 2 weeks prior to symptom onset (n = 371 (39.8%, 36.6-43.0%)), with the latter most commonly from pigs (n = 343 (36.9%, 33.8-40.1%). There was no association between an unknown aetiology and exposure to animals in a multivariate logistic regression. Further testing for unknown or undetected pathogens may increase diagnostic yield, however, given the high proportion of zoonotic pathogens and the presence of risk factors, increasing public awareness about zoonoses and preventive measures can be considered.

Virtual screening for novel Staphylococcus Aureus NorA efflux pump inhibitors from natural products.

NorA is a member of the Major Facilitator Superfamily (MFS) drug efflux pumps that have been shown to mediate antibiotic resistance in Staphylococcus aureus (SA). In this study, QSAR analysis, virtual screening and molecular docking were implemented in an effort to discover novel SA NorA efflux pump inhibitors. Originally, a set of 47 structurally diverse compounds compiled from the literature was used to develop linear QSAR models and another set of 15 different compounds were chosen for extra validation. The final model which was estimated by statistical values for the full data set (n = 45, Q(2) = 0.80, RMSE = 0.20) and for the external test set (n = 15, R(2) = 0.60, |res|max = 0.75, |res|min = 0.02) was applied on the collection of 182 flavonoides and the traditional Chinese medicine (TCM) database to screen for novel NorA inhibitors. Finally, 33 lead compounds that met the Lipinski's rules of five/three and had good predicted pIC50 values from in silico screening process were employed to analyze the binding ability by docking studies on NorA homology model in place of its unavailable crystal structures at two active sites, the central channel and the Walker B.