Bacterial infections can quickly turn into sepsis, with its attendant clinical sequelae of inflammation, tissue injury, and organ failure. Paradoxically, sustained inflammation in sepsis may lead to immune suppression, because of which the host is unable to clear the existing infection. Use of agents that suppress the inflammatory response may accelerate host immune suppression, whereas use of traditional antibiotics does not significantly affect inflammation. In this study, we investigated whether lipoxin A4 (LXA4), a specialized, proresolution lipid mediator, could increase neutrophil phagocytic activity as well as reduce bacterial virulence. Using the mouse cecal ligation and puncture (CLP) model of sepsis, the administration of LXA4 (7 μg/kg i.v.) 1 h after surgery increased neutrophil phagocytic ability and Fcγ receptor I (CD64) expression. Ex vivo studies have confirmed that the direct addition of LXA4 to CLP neutrophils increased phagocytic ability but not CD64 expression. LXA4 did not affect neutrophils taken from control mice in which CD64 expression was minimal. Taken together with in vivo data, these results suggest that LXA4 directly augments CD64-mediated neutrophil phagocytic ability but does not directly increase neutrophil CD64 expression. Bacterial communication and virulence is regulated by quorum sensing inducers. In Pseudomonas aeruginosa, virulence is induced with release of various virulence factors, by N-3-oxododecanolyl homoserine lactone binding to the quorum sensing receptor, LasR. We show that LXA4 is an inhibitor of LasR in P. aeruginosa and that it decreases the release of pyocyanin exotoxin. These results suggest that LXA4 has the novel dual properties of increasing host defense and decreasing pathogen virulence by inhibiting quorum sensing.-Wu, B., Capilato, J., Pham, M. P., Walker, J., Spur, B., Rodriguez, A., Perez, L. J., Yin, K. Lipoxin A4 augments host defense in sepsis and reduces Pseudomonas aeruginosa virulence through quorum sensing inhibition.

A newly developed portable capillary liquid chromatograph was investigated for the separation of various pharmaceutical and illicit drug compounds. The system consists of two high‐pressure syringe pumps capable of delivering capillary‐scale flow rates at pressures up to 10 000 psi. Capillary liquid chromatography columns packed with sub‐2 μm particles are housed in cartridges that can be inserted into the system and easily connected through high‐pressure fluidic contact points by simply applying a specific, predetermined torque rather than using standard fittings and less precise sealing protocols. Several over‐the‐counter analgesic drug separations are demonstrated, along with a simple online measurement of tablet dissolution. Twenty illicit drug compounds were also separated across six targeted drug panels. The results described in this study demonstrate the capability of this compact liquid chromatography instrument to address several important drug‐related applications while simplifying system operation, and greatly reducing solvent usage and waste generation essential for onsite analysis.

High-performance liquid chromatography is one of the primary techniques covered in the undergraduate analytical chemistry curriculum. This technology report describes the use of a portable capillary-scale instrument that can provide similar performance to a benchtop instrument but generates less solvent waste and enables operation in nonlaboratory settings. Comparisons between the two instrument types were made for single-standard calibration analysis of caffeine in diet soda and aspirin content in over-the-counter tablets, with relative percent differences between the standards and samples under 5% for both instrument types and both samples. The capability to use the instrument in lecture and outreach demonstration activities was also explored. Portable instruments can serve similar pedagogical purposes to traditional instruments as well as provide a platform to introduce discussions on green analytical chemistry based on differences in solvent waste generation and power consumption.