The co-occurrent microplastics and nano-CuO showed antagonistic inhibitory effects on bacterial denitrification: Interaction of pollutants and regulations on functional genes.

The wide occurrence of microplastics (MPs) and nanoparticles resulted in their inevitable coexistence in environment. However, the joint effects of these two types of particulate emerging contaminants on denitrification have seldomly been investigated. Herein, non-biodegradable polyvinyl chloride, polypropylene, polyethylene and biodegradable polyhydroxyalkanoate (PHA) MPs were chosen to perform the co-occurrent effects with nano copper oxide (nano-CuO). Both the nano-CuO and MPs inhibited the denitrification process, and biodegradable PHA-MPs showed severer inhibition than non-biodegradable MPs. However, the presence of MPs significantly alleviated the inhibition of nano-CuO, suggesting an antagonistic effect. Other than MPs decreasing copper ion release from nano-CuO, MPs and nano-CuO formed agglomerations and induced lower levels of oxidative stress compared to individual exposure. Transcriptome analysis indicated that the co-occurrent MPs and nano-CuO induced different regulation on denitrifying genes (e. g. nar and nor) compared to individual ones. Also, the expressions of genes involved in denitrification-associated metabolic pathways, including glycolysis and NADH electron transfer, were down-regulated by nano-CuO or MPs, but exhibiting recovery under the co-occurrent conditions. This study firstly discloses the antagonistic effect of nano-CuO and MPs on environmental process, and these findings will benefit the systematic evaluation of MPs environmental behavior and co-occurrent risk with other pollutants.

The efficacy and safety of montelukast in children with obstructive sleep apnea: a systematic review and meta-analysis.

OBJECTIVE: The efficacy and safety of montelukast in children with obstructive sleep apnea (OSA) remain controversial. Therefore, the aims of this systemic review and meta-analysis are to verify this issue and further provide reference for clinical practice. METHODS: Seven databases were searched for randomized controlled trials (RCTs) up to September 30, 2019. The literature screening and data extraction were performed by two independent researchers. Adverse reactions from trials were also recorded. Meta-analysis was performed and analyzed heterogeneity. Methodological and evidence quality were followed by to evaluate according to Cochrane handbook. RESULTS: A total of 4 RCTs including 305 children with mild to moderate OSA were involved. Compared with placebo, we found that oral montelukast (OM) significantly improved polysomnography (PSG) monitoring parameters, typical and relevant symptoms including snoring and mouth breathing, and adenoid morphology in children with OSA. When compared with routine drugs, not only PSG monitoring parameters and adenoid morphology, but also sleep-disordered breathing (SDB)-related questionnaire scores were improved in patients with OSA treated by combination of OM and routine drugs. In addition, compared with single nasal spray of mometasone furoate, the present study also showed that OM combined with nasal spray of mometasone furoate significantly improved PSG monitoring parameters, symptoms of snoring and mouth breathing and reduced tonsil morphology in pediatric OSA. In terms of treatment safety, one study reported adverse reactions of OM such as headache, nausea and vomiting, while no adverse events were reported after OM treatment in another study. CONCLUSION: As a classic leukotriene receptor antagonist, montelukast can be used to treat children with mild to moderate OSA in the short term and improve clinical characteristics. The promotion and application of OM in clinic is considered to be a noninvasive option to avoid surgical treatment.

Research on a novel chitosan microsphere/scaffold system by double crosslinkers.

RhBMP-2 has shown great promise for the reconstruction of teeth segmental bone defects due to its osteoinductive properties. But the application of rhBMP-2 is limited by its weak drug controled release. It is usually loaded in a Chitosan Microspheres (CMs) delivery system with excess single cross-linker and then removed before practice. In this study, cross-linkers were replaced with RhBMP-2 which contains vanillin and vitriolic acid, and thus CMs were developed. The materials were studied by SEM, FTIR and drug release experiments. It showed an ideal releasing profile and excellent osteoconductive and osteoinductive performance in the delivery system. Therefore, designing biomaterials with a controllable delivery system composite and releasing profile of rhBMP-2 are critical for applications of bone regeneration and tissue engineering.

The performance of thiol-terminated PEG-paclitaxel-conjugated gold nanoparticles.

A series of thiol-terminated polyethylene glycol (PEG)-paclitaxel (PTX) derivatives are designed and synthesized to fabricate PTX-conjugated gold nanoparticles (PTX@GNPs) and improve their overall performance. By extending the molecular weight of PEG from 400 to 1000 Da, the optimized water solubility of the conjugate reaches 184 mg/mL, equal to 4.6 × 10(5) times that of PTX alone (0.4 µg/mL). High drug loading is obtained by eliminating the steric hindrance between PTX molecules on the surface of GNPs. The gold conjugate shows double simultaneous stimulation-induced drug release behavior in the presence of both esterase and high concentrations of glutathione. The synergic release characteristics of this conjugate results in significant performance improvements, including prolonged circulation due to high stability in vivo, targeted release of PTX inside tumor cells, and increased tumor cell killing efficiency. Improving the in vitro properties of the conjugate not only significantly enhances its therapeutic efficacy in a murine liver cancer model, but also allows drug-conjugated gold nanoparticles to be used as a promising nanoprodrug system in the cancer therapeutics.