BackgroundThe α2-adrenoreceptor agonist dexmedetomidine is known to provide renoprotection against ischemia and reperfusion (I/R) injury. However the underlying molecular mechanisms remain unclear. The purpose of this study was to investigate whether the Janus kinase and signal transducer and activator of transcription (JAK/STAT) signaling pathway plays a role in dexmedetomidine’s renoprotection.MethodsI/R model was induced by bilateral renal pedicle clamping for 45 min followed by 48 h of reperfusion in male Wistar rat. Sham laparotomy served as controls. Animals received dexmedetomidine (50 μg/kg, i.p.) in the absence or presence of atipamezole (250 μg/kg, i.p.), or vehicle (DMSO) in the absence or presence of selective JAK2 inhibitor tyrphostin AG490 (10 mg/kg, i.p.) before ischemia. Renal function, histology, apoptosis, expression of cleaved caspase 3 protein, intercellular adhesion molecule-1 (ICAM-1), monocyte chemoattractant protein-1 (MCP-1) and phosphorylations of JAK2, STAT1 and STAT3 were assessed.ResultsThe animals treated with either dexmedetomidine or AG490 exhibited an improved renal functional recovery, attenuated histological lesions and reduced number of apoptotic tubular epithelial cells. Either dexmedetomidine or AG490 inhibited the phosphorylations of JAK2 and its downstream molecule STAT1 and STAT3, accompanied by down-regulation the expression of cleaved caspase 3, ICAM-1 and MCP-1 proteins, and significantly ameliorated renal I/R injury.ConclusionsDexmedetomidine protects kidney against I/R injury, at least in part, through its inhibitory effects on injury-induced activation of JAK/STAT signaling pathway. If our data can be extrapolated to clinical setting, then dexmedetomidine may therefore serve as a clinical strategy to treat/prevent perioperative renal I/R injury.

Severe acute respiratory syndrome–associatedcoronavirus (SARS-CoV) was isolated from a pig during a survey for possible routes of viral transmission after a SARS epidemic. Sequence and epidemiology analyses suggested that the pig was infected by a SARS-CoV of human origin.

Deep-sea sediments contain high concentrations of rare earth element (REE) which have been regarded as a huge potential resource. Understanding the marine REE cycle is important to reveal the mechanism of REE enrichment. In order to determine the geochemistry characteristics and migration processes of REE, seawater, porewater and sediment samples were systematically collected from the western Pacific for REE analysis. The results show a relatively flat REE pattern and the HREE (Heavy REE) enrichment in surface and deep seawater respectively. The HREE enrichment distribution patterns, low concentrations of Mn and Fe and negative Ce anomaly occur in the porewater, and high Mn/Al ratios and low U concentrations were observed in sediment, indicating oxic condition. LREE (Light REE) and MREE (Middle REE) enrichment in upper layer and depletion of MREE in deeper layer were shown in porewater profile. This study suggests that porewater flux in the western Pacific basin is a minor source of REEs to seawater, and abundant REEs are enriched in sediments, which is mainly caused by the extensive oxic condition, low sedimentation rate and strong adsorption capacity of sediments. Hence, the removal of REEs of porewater may result in widespread REE-rich sediments in the western Pacific basin.

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Biofilms that contribute to the persistent bacterial infections pose serious threats to human health, due in part to the extracellular polymeric substances (EPS) matrix of biofilm block the diffusion of intact antimicrobials. The poor penetration of antimicrobials into biofilm greatly reduces their bacterial killing efficacy. Here, we have demonstrated a nanocapsule PMPC–CS synthesized by encapsulating a chitosan nanoparticle with poly­(2-methacryloyloxyethyl phosphorylcholine) (PMPC). Such PMPC-based surface exhibited low EPS-adsorption, allowing enhanced penetration of PMPC–CS. Additionally, PMPC–CS showed effective targeting toward negatively charged bacterial cell surfaces and pH-responsive drug release mediated by the swelling of chitosan core under the acidic environment of biofilm. These unique features ensured targeted delivery of antimicrobials throughout the depth of a biofilm. Delivery of triclosan with PMPC–CS outperformed direct application of free triclosan in inhibiting the growth of bacteria in biofilm, suggesting the potential of PMPC–CS as an effective delivery system for the treatment of bacterial infections.