Opioids are widely prescribed analgesics, but their use is limited due to development of tolerance and addiction, as well as high variability in individual response. The development of improved opioid analgesics requires high-throughput functional assays to assess large numbers of potential opioid ligands. In this study, we assessed the ability of a proprietary "no-wash" fluorescent membrane potential dye to act as a reporter of µ-opioid receptor (MOR) activation and desensitization via activation of G-protein-coupled inwardly rectifying potassium channels. AtT-20 cells stably expressing mouse MOR were assayed in 96-well plates using the Molecular Devices FLIPR membrane potential dye. Dye emission intensity decreased upon membrane hyperpolarization. Fluorescence decreased in a concentration-dependent manner upon application of a range of opioid ligands to the cells, with high-efficacy agonists producing a decrease of 35% to 40% in total fluorescence. The maximum effect of morphine faded in the continued presence of agonist, reflecting receptor desensitization. The effects of opioids were prevented by prior treatment with pertussis toxin and blocked by naloxone. We have demonstrated this assay to be an effective method for assessing ligand signaling at MOR, which may potentially be scaled up as an additional high-throughput screening technique for characterizing novel opioid ligands.

SignificanceAgonists of the μ-opioid receptor (MOPr) are currently the gold standard for pain treatment. However, their therapeutic usage is greatly limited by side effects including respiratory depression, constipation, tolerance, and dependence. Functionally selective MOPr agonists that mediate their effects preferentially through G proteins rather than β-arrestin signaling are believed to produce fewer side effects. Here, we present the discovery of 3 unusual tetrapeptides with a unique stereochemical arrangement of hydrophobic amino acids from an Australian estuarine isolate of Penicillium species. Building on these natural templates we developed bilorphin, a potent and selective highly G protein-biased agonist of the MOPr. Further, through the addition of a simple sugar moiety, we generated bilactorphin that is an effective analgesic in vivo.

BackgroundTo investigate the perioperative and oncological outcomes of gastric cancer (GC) after robotic versus laparoscopic gastrectomy (RG versus LG), we carried out a meta-analysis of propensity score matching (PSM) studies and randomized controlled study (RCT) to compare the safety and overall effect of RG to LG for patients with GC.MethodsPubMed, Web of Science, EMBASE, and Cochrane Central Register were searched based on a defined search strategy to identify eligible PSM and RCT studies before July 2021. Data on perioperative and oncological outcomes were subjected to meta-analysis.ResultsOverall, we identified 19 PSM studies and 1 RCT of RG versus LG, enrolling a total of 13,446 patients (6,173 and 7,273 patients underwent RG and LG, respectively). The present meta-analysis revealed nonsignificant differences in tumor size, proximal resection margin distance, distal resection margin distance, abdominal bleeding, ileus, anastomosis site leakage, duodenal stump leakage rate, conversion rate, reoperation, overall survival rate, and long-term recurrence-free survival rate between the two groups. Alternatively, comparing RG with LG, RG has a longer operative time (p < 0.00001), less blood loss (p <0.0001), earlier time to first flatus (p = 0.0003), earlier time to oral intake (p = 0.0001), shorter length of stay (p = 0.0001), less major complications (p = 0.0001), lower overall complications (p = 0.0003), more retrieved lymph nodes (P < 0.0001), and more cost (p < 0.00001).ConclusionsIn terms of oncological adequacy and safety, RG is a feasible and effective treatment strategy for gastric cancer but takes more cost in comparison with LG.

Carbon monoxide (CO), as a crucial gasotransmitter, is endogenously produced by the degradation of heme and plays a critical role in regulating various physiological and pathophysiological processes such as oxidative stress. Thus, an effective fluorescent probe for investigating the relationships between CO and oxidative stress in vivo is necessary. In this paper, a ratiometric near-infrared (NIR) fluorescent probe (CP-CO) based on a coumarin-benzopyran fluorophore for imaging CO is developed. CP-CO itself displays strong coumarin emission due to its spironolactone structure. After the probe is reacted with CO and PdCl 2 , a notable enhancement of emission intensity at 690 nm can be found, which results in an obvious red shift of emission (200 nm). Moreover, CP-CO exhibits high sensitivity toward CO and produces a high enhancement ratio (203-fold). In addition, the probe is applied for ratiometric monitoring of exogenous and endogenous CO levels in HepG2 cells. Furthermore, the fluorescence imaging of CP-CO in zebrafish is performed by twophoton excitation along with excellent penetration ability. Most importantly, CP-CO can visualize the upregulation of CO under lipopolysaccharide (LPS)-induced oxidative stress in a zebrafish model, which vividly reveals its excellent ability in the elucidation of CO function in related biological events.

Background Microaspiration of secretions around the tracheal cuff is a multifactorial process. Tracheal cuff shape might take a major part in its occurrence. The rationale for producing a taper-shaped cuff is established on the assumption that compared to a conventional cuff with a single fixed diameter, a continuum of minimum-to-maximum diameter sections might better fit the tracheal walls. Objectives The primary objective of this meta-analysis was to compare ventilator-associated pneumonia (VAP) between tapered-cuff intubation and conventional-cuff intubation. The secondary objective was to compare intensive care unit (ICU) mortality between tapered-cuff intubation and conventional-cuff intubation. Methods We searched the Cochrane Library, Embase, MEDLINE database through the PubMed search engine, and CINAHL from inception to April 2018. Randomized trials comparing VAP and ICU mortality between tapered-cuff intubation and conventional-cuff intubation in intubated adults were included. Two review authors assessed study quality and abstracted databasing on prespecified criteria independently. Results We pooled summary estimates from 5 trials evaluating tapered-cuff involving 774 participants. Compared to VAP, no statistically significant difference was observed between the tapered-cuff and conventional-cuff groups (OR 0.82, CI 0.61–1.12, z = 1.24, and p=0.21). No statistically significant difference was observed between the tapered-cuff and conventional-cuff groups with ICU mortality (OR 0.77, CI 0.55–1.08, z = 1.49, and p=0.14). Conclusions In this meta-analysis, the tapered-cuff tracheal tube may not be superior to the standard-cuff tracheal tube in reducing VAP and ICU mortality.