Correlations between the ECD spectra and absolute configuration of bridged-ring lactones: revisiting Beecham's rule.

Bridged lactones frequently appear as structural fragments in natural products. To elucidate their stereochemistry using electronic circular dichroism (ECD) spectra, Beecham correlated the sign of the Cotton effect (CE) from the n → π* transition of lactones at approximately 220 nm with the skeleton of bridged lactones. By combining experimental and theoretical ECD analyses of various bridged lactones using time-dependent density functional theory calculations and a methodology for extracting core structures, Beecham's rule was revisited and revised to define the scope of application. Both the position of the ß-C atom in the larger lactone system and the additive contribution of groups at ß-C exerted effects on the sign of the CE. The revised rule provides an alternative way to interpret experimental ECD data in addition to quantum-chemical calculation for various bridged lactones.

Base-promoted domino radical cyclization of 1,6-enynes.

A good regioselective, high atom-economical and transition-metal-free method for the synthesis of α-functionalized ether derivatives via the domino radical cyclization of 1,6-enynes is described. A series of α-functionalized ether derivatives could be easily obtained in good yields with wide functional group tolerance by using less toxic and inexpensive Cs2CO3 as the base. The control experiment results show that the reaction involves a radical process. This strategy provides a regioselective way toward the formation of dual C-C bonds in one step.

Efficacy and safety of Aprepitant-containing triple therapy for the prevention and treatment of chemotherapy-induced nausea and vomiting: A meta-analysis.

BACKGROUND: Most cancer patients suffer from the pain of chemotherapy-induced nausea and vomiting (CINV). This meta-analysis was performed to evaluate the efficacy and safety of a regimen consisting of aprepitant, dexamethasone, and 5-HT3 receptor antagonists in the prevention and treatment of CINV. METHODS: A systematic literature search was conducted across multiple databases, including PubMed, EMbase, Cochrane Library, MEDLINE, CENTRAL, HEED, CNKI, Wanfang, and VIP, to identify randomized controlled trials (RCTs) investigating the use of triple therapy (aprepitant, 5-HT3 receptor antagonist, and dexamethasone) to prevent and treat CINV. Meta-analysis was performed using RevMan 5.4 and Stata17 software, employing either a fixed-effect or random-effect model based on statistical heterogeneity. RESULTS: A meta-analysis of 23 randomized controlled trials (RCTs) involving 7956 patients was conducted. Efficacy: Results showed significantly improved complete responses (CRs) for CINV in the test group versus the control group in the overall, acute, and delayed phases. Furthermore, in the test group, substantial alleviation of nausea symptoms was observed in the delayed and overall phases but not in the acute phase. Safety: There was no statistically significant difference in the incidence of febrile neutropenia, diarrhea, anorexia, and headache between the 2 groups. The incidence of fatigue and hiccups in the test group was higher than that in the control group; however, the incidence of constipation was significantly lower. CONCLUSIONS: Aprepitant-containing triple therapy is highly effective in the prevention and treatment of CINV, with reliable medication safety.

Specific chiroptical sensing of cysteine via ultrasound-assisted formation of disulfide bonds in aqueous solution.

Cysteine (Cys) can serve as a biomarker to indicate diseases or disorders, and its chiral sensing has attracted increasing attention. Herein, we established an ultrasound-facilitated chiral sensing method for Cys using 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) and electronic circular dichroism (ECD) spectroscopy. The formation of chiral disulfide bonds induced degenerate exciton coupling between two NBD chromophores, resulting in intense Cotton effects (CEs) of the sensing product. The anisotropy factor (g) was linearly correlated with the enantiomeric excess of Cys across the visible region (400-500 nm), and other natural amino acids or biothiols did not interfere with the detection. This ultrasound-promoted efficient and specific chiral sensing method of Cys has potential for application in the diagnosis of related diseases.

A rapid bioassay for recombinant interleukin-22.

Interleukin-22 is a novel cytokine produced mainly in activated T cells. The elaborate biological functions of IL-22 in vivo are still widely unknown. In this report, we describe a rapid, simple, and reproducible in vitro cell-based bioassay for measuring the bioactivity of recombinant interleukin-22 (IL-22) to study the primary function of IL-22 in vivo. Human hepatocyte cell line (HepG2) was transfected with pSTAT3-Luc, a plasmid carrying the luciferase gene under the control of STAT3. After screening and selection, one stable clone was established which generates a strong response to recombinant human IL-22 (rhIL-22) stimulation in a dose-dependent manner. The cell showed ED50 of 17.0 +/- 1.4 ng/mL (n = 15) to recombinant human IL-22. Pre-incubation of anti-IL-22 mAb with IL-22 recombinant proteins completely blocked the bioactivities. The assay can be completed within one day. The current assay provides a rapid analytical method to measure the biological activity of IL-22 in vitro.

[Study on the detection method for determining the bioactivity of recombinant human interleukin-22].

OBJECTIVE: To develop a method for determining the bioactivity of recombinant human IL-22. METHODS: pSTAT3-TA-Luc and pcDNA3. 1 plasmids were co-transfect to HepG2 cells to generate stable HepG2/ STAT3 cell line with G418 screen. After treating cell with IL-22, the luciferase activity was assayed. Orthogonal test was used to optimize the assay condition, and then the reproducibility and specificity of the assay was checked. RESULTS: The best condition for this assay are: cell density as 4 x 10(5)/mL, stimulating time as 4 hours, luciferase substrate as 50 microL. 50% effective dose (ED50) of IL-22 assayed by this method is 16.89 ng/mL, relative standard deviation (RSD) is 7.09%. Neutralizing antibody test shows the high specificity. Comparing with ELISA, the method described here has more advantages, including higher stability, easier performance and less cost. CONCLUSION: Luciferase reporter gene assay method is a fast, sensitive, reproducible method for IL-22 bioactivity determination.