Palladium-Catalyzed Arylation of Endocyclic 1-Azaallyl Anions: Concise Synthesis of Unprotected Enantioenriched cis-2,3-Diarylpiperidines.

Unprotected cis-2,3-diarylpiperidines are synthesized through an unprecedented palladium-catalyzed cross-coupling reaction between aryl halides and elusive endocyclic 1-azaallyl anions. These intermediates are generated in situ by the deprotonation of 2-aryl-1-piperideines, precursors that are readily prepared in two operations from simple piperidines. An asymmetric version of this reaction with (2R, 3R)-iPr-BI-DIME as the ligand provides products in moderate to good yields and enantioselectivities. This study significantly expands the synthetic utility of endocyclic 1-azaallyl anions.

Piperidine Derivatives: Recent Advances in Synthesis and Pharmacological Applications.

Piperidines are among the most important synthetic fragments for designing drugs and play a significant role in the pharmaceutical industry. Their derivatives are present in more than twenty classes of pharmaceuticals, as well as alkaloids. The current review summarizes recent scientific literature on intra- and intermolecular reactions leading to the formation of various piperidine derivatives: substituted piperidines, spiropiperidines, condensed piperidines, and piperidinones. Moreover, the pharmaceutical applications of synthetic and natural piperidines were covered, as well as the latest scientific advances in the discovery and biological evaluation of potential drugs containing piperidine moiety. This review is designed to help both novice researchers taking their first steps in this field and experienced scientists looking for suitable substrates for the synthesis of biologically active piperidines.

Benzoxazole-appended piperidine derivatives as novel anticancer candidates against breast cancer.

Novel series of benzoxazole-appended piperidine derivatives were planned, synthesized and screened against two breast cancer cell lines. Considerable antiproliferative activity was observed for screened compounds (IC50 = 33.32 ± 0.2 µM to 7.31 ± 0.43 µM and 1.66 ± 0.08 µM to 12.10 ± 0.57 µM) against MCF-7 and MDA-MB-231 cell lines respectively being more potent than doxorubicin (IC50 = 8.20 ± 0.39 µM and 13.34 ± 0.63 µM respectively). Active compounds were submitted for enzyme inhibition assays when 4d and 7h demonstrated potent EGFR inhibition (0.08 ± 0.002 µM and 0.09 ± 0.002 µM respectively) compared to erlotinib (0.11 ± 0.003 µM). However, no one compound displayed effective ARO inhibition activity as tested compounds were less active than letrozole. Apoptosis inducing ability results implied that apoptosis was provoked by significant stimulation of caspase-9 protein levels (4.25-7.04-fold) upon treatment of MCF-7 cells with 4a, 7h, 9, 12e and 12f. Alternatively, MDA-MB-231 cells treated with 4d, 7a, 12b and 12c considerably increased caspase-9 levels (2.32-4.06-fold). Cell cycle arrest and annexin-V/Propidium iodide assays further confirmed apoptosis when tested compounds arrested cell cycle at various phases and demonstrated high annexin V binding affinity. Docking outcomes proved valuable binding affinities for compounds 4d and 7h to EGFR enzyme while compounds 4a and 12e, upon docking into the active site of ARO, failed to interact with heme, suggesting their inabilities to act as AIs. Therefore, these benzoxazoles can act as promising candidates exhibiting EGFR inhibition and apoptosis-promoting properties.

Genome-wide expression screening in the cardiac embryonic stem cell test shows additional differentiation routes that are regulated by morpholines and piperidines.

The cardiac embryonic stem cell test (ESTc) is a well-studied non-animal alternative test method based on cardiac cell differentiation inhibition as a measure for developmental toxicity of tested chemicals. In the ESTc, a heterogenic cell population is generated besides cardiomyocytes. Using the full biological domain of ESTc may improve the sensitivity of the test system, possibly broadening the range of chemicals for which developmental effects can be detected in the test. In order to improve our knowledge of the biological and chemical applicability domains of the ESTc, we applied a hypothesis-generating data-driven approach on control samples as follows. A genome-wide expression screening was performed, using Next Generation Sequencing (NGS), to map the range of developmental pathways in the ESTc and to search for a predictive embryotoxicity biomarker profile, instead of the conventional read-out of beating cardiomyocytes. The detected developmental pathways included circulatory system development, skeletal system development, heart development, muscle and organ tissue development, and nervous system and cell development. Two pesticidal chemical classes, the morpholines and piperidines, were assessed for perturbation of differentiation in the ESTc using NGS. In addition to the anticipated impact on cardiomyocyte differentiation, the other developmental pathways were also regulated, in a concentration-response fashion. Despite the structural differences between the morpholine and piperidine pairs, their gene expression effect patterns were largely comparable. In addition, some chemical-specific gene regulation was also observed, which may help with future mechanistic understanding of specific effects with individual test compounds. These similar and unique regulations of gene expression profiles by the test compounds, adds to our knowledge of the chemical applicability domain, specificity and sensitivity of the ESTc. Knowledge of both the biological and chemical applicability domain contributes to the optimal placement of ESTc in test batteries and in Integrated Approaches to Testing and Assessment (IATA).

Exploration of Spirocyclic Derivatives of Ciprofloxacin as Antibacterial Agents.

The previously reported as well as newly synthesized derivatives of the 1-oxa-9-azaspiro[5.5]undecane were employed in the synthesis of thirty-six derivatives of ciprofloxacin using commercially available 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid and the literature protocol involving the preparation of boron chelate complex to facilitate nucleophilic aromatic substitution. All new fluoroquinolone derivatives were tested against two gram-positive as well as three gram-negative strains of bacteria. With the activity spectrum of the new derivatives being substantially narrower than that of ciprofloxacin, compounds were distinctly active against two of the five strains: gram-negative Acinetobacter baumannii 987® and gram-positive Bacillus cereus 138®. Towards these two strains, a large group of compounds displayed equal or higher potency than ciprofloxacin.

Synthesis of Aminoethyl-Substituted Piperidine Derivatives as σ1 Receptor Ligands with Antiproliferative Properties.

A series of novel σ1 receptor ligands with a 4-(2-aminoethyl)piperidine scaffold was prepared and biologically evaluated. The underlying concept of our project was the improvement of the lipophilic ligand efficiency of previously synthesized potent σ1 ligands. The key steps of the synthesis comprise the conjugate addition of phenylboronic acid at dihydropyridin-4(1H)-ones 7, homologation of the ketones 8 and introduction of diverse amino moieties and piperidine N-substituents. 1-Methylpiperidines showed particular high σ1 receptor affinity and selectivity over the σ2 subtype, whilst piperidines with a proton, a tosyl moiety or an ethyl moiety exhibited considerably lower σ1 affinity. Molecular dynamics simulations with per-residue binding free energy deconvolution demonstrated that different interactions of the basic piperidine-N-atom and its substituents (or the cyclohexane ring) with the lipophilic binding pocket consisting of Leu105, Thr181, Leu182, Ala185, Leu186, Thr202 and Tyr206 are responsible for the different σ1 receptor affinities. Recorded logD7.4 and calculated clogP values of 4a and 18a indicate low lipophilicity and thus high lipophilic ligand efficiency. Piperidine 4a inhibited the growth of human non-small cell lung cancer cells A427 to a similar extent as the σ1 antagonist haloperidol. 1-Methylpiperidines 20a, 21a and 22a showed stronger antiproliferative effects on androgen negative human prostate cancer cells DU145 than the σ1 ligands NE100 and S1RA.

Characterization of Queen Supergene Pheromone in the Red Imported Fire Ant Using Worker Discrimination Assays.

Ants use chemical signals to communicate for various purposes related to colony function. Social organization in the red imported fire ant, Solenopsis invicta, is determined by the Sb supergene, with colonies of the monogyne (single-queen) form lacking the element and colonies of the polygyne (multiple-queen) form possessing it. Polygyne workers accept new reproductive queens in their nest, but only those carrying Sb; young winged queens lacking this genetic element are executed as they mature sexually in their natal nest or as they attempt to enter a foreign nest to initiate reproduction after mating and shedding their wings. It has been suggested that queen supergene genotype status is signaled to workers by unsaturated cuticular hydrocarbons, while queen reproductive status is signaled by piperidines (venom alkaloids). We used high-throughput behavioral assays to study worker acceptance of paper dummies dosed with fractions of extracts of polygyne queens, or blends of synthetic counterparts of queen cuticular compounds. We show that the queen supergene pheromone comprises a blend of monoene and diene unsaturated hydrocarbons. Our assays also reveal that unsaturated hydrocarbons elicit discrimination by polygyne workers only when associated with additional compounds that signal queen fertility. This synergistic effect was obtained with a polar fraction of queen extracts, but not by the piperidine alkaloids, suggesting that the chemical(s) indicating queen reproductive status are compounds more polar than cuticular hydrocarbons but are not the piperidine alkaloids. Our results advance understanding of the role of chemical signaling that is central to the regulation of social organization in an important invasive pest and model ant species.

Preparation of N- 18F-fluoroethyl-tofacitinib and its application in the imaging of rheumatoid arthritis / 中华核医学与分子影像杂志

Objective:To synthesize N- 18F-fluoroethyl-tofacitinib, and explore its feasibility in the diagnosis of rheumatoid arthritis (RA). Methods:The " two-step method" was used to modify tofacitinib with 18F-fluoroethyl, and the labeling rate and radiochemical purity of the probe were measured by high performance liquid chromatography (HPLC), and the stabilities of the probe in vivo and in vitro were investigated. BALB/c mice (normal group; n=3) and collagen-induced arthritis (CIA) model mice (CIA group; n=3) were injected with N- 18F-fluoroethyl-tofacitinib and CIA model mice injected with tofacitirrib and N- 18F-fluoroethyl-tofacitinib were as blocking group ( n=3). All mice underwent microPET imaging and the percentage injection dose per gram of tissue (%ID/g) and the uptake ratio of inflamed joints to muscle (T/M) were calculated. One-way analysis of variance and the least significant difference (LSD) t test were used to analyze the data. Results:The synthesis time of N- 18F-fluoroethyl-tofacitinib was about 120 min, with the yield approximately 1%, the specific activity >13.6 GBq/μmol, and the radiochemical purity >99%. After the probe incubated with PBS, plasma or in vivo for 2 h, the radiochemical purity was still more than 95%. MicroPET imaging showed that 30 min after injection, the uptake of N- 18F-fluoroethyl-tofacitinib in the inflamed joints of CIA group was higher than that of normal group and blocking group ((10.22±1.64), (2.71±0.26) and (2.81±0.33) %ID/g; F=58.26, t values: 7.83, 7.67, P values: 0.001, 0.002). The T/M of CIA group was also higher than that of normal group and blocking group (24.73±5.77, 2.75±1.36 and 2.89±0.54; F=40.64, t values: 6.42, 6.53, P values: 0.003, 0.003). Conclusions:N- 18F-fluoroethyl-tofacitinib is successfully prepared and it is stable in vitro with good imaging performance in vivo. It may be used in clinic for the diagnosis of RA.

Relationship between autophagy and oxidative stress during remifentanil-induced hyperalgesia in rats with incisional pain / 中华麻醉学杂志

Objective:To evaluate the relationship between autophagy and oxidative stress during remifentanil-induced hyperalgesia in the rats with incisional pain.Methods:Thirty-two clean-grade healthy male Sprague-Dawley rats, weighing 230-250 g, aged 2-3 months, were divided into 4 groups ( n=8 each) using a random number table method: incisional pain group (I group), remifentanil + incisional pain group (RI group), autophagy inhibitor 3-methyladenine + remifentanil + incisional pain group (MRI group) and autophagy agonist rapamycin group + remifentanil + incisional pain group (RRI group). The model of incision pain was developed and the equal volume of normal saline was intravenously infused simultaneously for 60 min.In RI, MRI and RRI groups, the model of incision pain was developed and remifentanil 1 μg·kg -1·min -1 was simultaneously infused for 60 min.In MRI group, 3-methyladenine 15 mg/kg was intraperitoneally injected at 12 h before developing the model, and rapamycin 10 mg/kg was intraperitoneally injected at 12 h before developing the model in RRI group.Thermal paw withdrawal latency (TWL) and mechanical paw withdrawal threshold (MWT) were measured at 24 h before infusion of remifentanil or normal saline (T 0) and at 2, 6, 24 and 48 h after the end of infusion (T 1-4). The rats were sacrificed after the end of behavioral testing, and the lumbar enlargement segments of the spinal cord were harvested for determination of the expression of autophagy microtubule-associated protein 1 light chain 3Ⅱ (LC3Ⅱ), Beclin-1 and P62 (by Western blot), activity of superoxide dismutase (SOD) (by xanthine oxidase method) and content of malondialdehyde (MDA) (by thiobarbital method). Results:Compared with the baseline at T 0, PWT was significantly decreased and TWL was shortened at T 1-4 in the four groups ( P<0.05). Compared with I group, MWT was significantly decreased and TWL was shortened at T 1-4, the expression of LC3 Ⅱand Beclin-1 was up-regulated, the expression of P62 was down-regulated, SOD activity was decreased, and MDA content was increased in RI group ( P<0.05). Compared with RI group, MWT was significantly decreased and TWL was shortened at T 1-4, the expression of LC3 Ⅱand Beclin-1 was down-regulated, the expression of P62 was up-regulated, SOD activity was decreased, and MDA content was increased in MRI group ( P<0.05), and MWT was significantly increased and TWL was prolonged at T 1-4, the expression of LC3 Ⅱand Beclin-1 was up-regulated, the expression of P62 was down-regulated, SOD activity was increased, and MDA content was decreased in RRI group ( P<0.05). Conclusions:Autophagy is involved in the process of remifentanil-induced incisional hyperalgesia through regulating the level of oxidative stress in rats.

Gene regulation by morpholines and piperidines in the cardiac embryonic stem cell test.

The cardiac embryonic stem cell test (ESTc) is an in vitro embryotoxicity screen which uses cardiomyocyte formation as the main differentiation route. Studies are ongoing into whether an improved specification of the biological domain can broaden the applicability of the test, e.g. to discriminate between structurally similar chemicals by measuring expression of dedicated gene transcript biomarkers. We explored this with two chemical classes: morpholines (tridemorph; fenpropimorph) and piperidines (fenpropidin; spiroxamine). These compounds cause embryotoxicity in rat such as cleft palate. This malformation can be linked to interference with retinoic acid balance, neural crest (NC) cell migration, or cholesterol biosynthesis. Also neural differentiation within the ESTc was explored in relation to these compounds. Gene transcript expression of related biomarkers were measured at low and high concentrations on differentiation day 4 (DD4) and DD10. All compounds showed stimulating effects on the cholesterol biosynthesis related marker Msmo1 after 24 h exposure and tridemorph showed inhibition of Cyp26a1 which codes for one of the enzymes that metabolises retinoic acid. A longer exposure duration enhanced expression levels for differentiation markers for cardiomyocytes (Nkx2-5; Myh6) and neural cells (Tubb3) on DD10. This readout gave additional mechanistic insight which enabled previously unavailable in vitro discrimination between the compounds, showing the practical utility of specifying the biological domain of the ESTc.

Synthesis and Characterization of Novel Methyl (3)5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates.

Series of methyl 3- and 5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates were developed and regioselectively synthesized as novel heterocyclic amino acids in their N-Boc protected ester form for achiral and chiral building blocks. In the first stage of the synthesis, piperidine-4-carboxylic and (R)- and (S)-piperidine-3-carboxylic acids were converted to the corresponding ß-keto esters, which were then treated with N,N-dimethylformamide dimethyl acetal. The subsequent reaction of ß-enamine diketones with various N-mono-substituted hydrazines afforded the target 5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates as major products, and tautomeric NH-pyrazoles prepared from hydrazine hydrate were further N-alkylated with alkyl halides to give 3-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates. The structures of the novel heterocyclic compounds were confirmed by 1H-, 13C-, and 15N-NMR spectroscopy and HRMS investigation.

Synthesis of Spirocyclic Piperidines by Radical Hydroarylation.

Reported here are conditions for the construction of spirocyclic piperidines from linear aryl halide precursors. These conditions employ a strongly reducing organic photoredox catalyst in combination with a trialkylamine reductant to achieve formation of aryl radical species. Regioselective cyclization followed by hydrogen-atom transfer affords a range of complex spiropiperidines. This system operates efficiently under mild conditions without the need for toxic reagents or precious metals.

Computational study on subfamilies of piperidine derivatives: QSAR modelling, model external verification, the inter-subset similarity determination, and structure-based drug designing.

A new subset of furan-pyrazole piperidine derivatives was used for QSAR model development. These compounds exhibit good Akt1 inhibitory activity; moreover, antiproliferative activities in vitro against OVCAR-8 (Human ovarian carcinoma cells) and HCT116 (human colon cancer cells), were confirmed for them. Based on the relevant three-dimensional (3D) and 2D autocorrelation descriptors, selected by genetic algorithm (GA), multiple linear regression (MLR) was established on half maximal-inhibitory concentration (IC50), in Akt1 and cancer cell lines independently. Robustness, stability, and predictive ability of the models were evaluated using external and internal validation (r2: 0.742-0.832, Q2LOO: 0.684-0.796, RMSE: 0.247-0.299, F: 32.283-57.578, and r2y-random: 0.049-0.080). Furthermore, in the new strategy, each of the evaluated models was generalized to two other subfamilies of piperidines to simultaneously compare the activities and structural similarity of these three subsets. Probably, structural similarity can be more considered as a criterion of similarity in the mechanism of action. Also, external verification of suggested predictive models was performed by another subset. Finally, by focusing on M64 as the most potent in vivo antitumor compound, 15 new derivatives were designed and six potent candidates were proposed for further investigation.

Role of spinal P2Y1R in development of remifentanil-induced hyperalgesia in rats with incisional pain: relationship with function of NR1 and NR2B in spinal cord / 中华麻醉学杂志

Objective:To evaluate the role of spinal P2Y1R in the development of remifentanil-induced hyperalgesia in rats with incisional pain (IP) and the relationship with the function of NR1 and NR2B in spinal cord.Methods:Forty-eight healthy adult male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, in which intrathecal catheters were successfully placed, were divided into 6 groups ( n=8 each) using a random number table method: control group (group C), P2Y1R antagonist MRS2179 group (group M), remifentanil group (group R), remifentanil plus MRS2179 group (group R+ M), IP plus remifentanil group (group I+ R) and IP plus remifentanil plus MRS2179 group (group I+ R+ M). In group C, normal saline 10 μl was intrathecally injected, and 10 min later normal saline was infused for 60 min via the tail vein at a rate of 0.1 ml·kg -1·min -1.In group M, MRS2179 0.6 nmol/kg was intrathecally injected, and 10 min later normal saline was infused for 60 min via the tail vein at a rate of 0.1 ml·kg -1·min -1.In group R, normal saline 10 μl was intrathecally injected, and 10 min later remifentanil was infused for 60 min via the tail vein at a rate of 1 μg·kg -1·min -1.In group R+ M, MRS2179 0.6 nmol/kg was intrathecally injected, and 10 min later remifentanil was infused for 60 min at a rate of 1 μg·kg -1·min -1 via the tail vein.In group I+ R, normal saline 10 μl was intrathecally injected, 10 min later remifentanil was infused for 60 min via the tail vein at a rate of 1 μg·kg -1·min -1, and IP was established at 10 min after onset of remifentanil infusion.In group I+ R+ M, MRS2179 0.6 nmol/kg was intrathecally injected, 10 min later remifentanil was infused via the tail vein for 60 min at a rate of 1 μg·kg -1·min -1, and IP was established at 10 min after onset of remifentanil infusion.The mechanical paw withdrawal threshold (MWT), thermal paw withdrawal latency (TWL), and the number of paw lifts on the cold plate were measured at 24 h before infusion of remifentanil or normal saline and at 2, 6, 24, and 48 h after the end of infusion.The animals were sacrificed after the last measurement of the pain threshold, L 4-6 segments of the spinal cord were removed for determination of the expression of P2Y1R, phosphorylated NR1 (p-NR1), NR1, phosphorylated NR2B (p-NR2B) and NR2B (by Western blot), for calculation of the ratios of p-NR1/NR1 and p-NR2B/NR2B, and for detection of expression of P2Y1R mRNA, NR1 mRNA and NR2B mRNA (by real-time polymerase chain reaction). Results:Compared with group C, MWT was significantly decreased, TWL was shortened, the number of paw lifts on the cold plate was increased, the expression of P2Y1R protein and mRNA, NR1 protein and mRNA, p-NR1, NR2B protein and mRNA and p-NR2B was up-regulated, and p-NR1/NR1 ratio and p-NR2B/NR2B ratio were increased in group R ( P<0.01). Compared with group R, MWT was significantly increased, TWL was prolonged, the number of paw lifts on the cold plate was decreased, the expression of P2Y1R, p-NR1, NR1 protein and mRNA, p-NR2B, NR2B protein and mRNA was down-regulated, and p-NR1/NR1 ratio and p-NR2B/NR2B ratio were decreased in group R+ M ( P<0.05 or 0.01). Compared with group I+ R, MWT was significantly increased, TWL was prolonged, the number of paw lifts on the cold plate was decreased, the expression of P2Y1R, p-NR1, NR1 protein and mRNA, p-NR2B, NR2B protein and mRNA was down-regulated, and p-NR1/NR1 ratio and p-NR2B/NR2B ratio were decreased in group I+ R+ M ( P<0.01). Conclusion:Spinal P2Y1R can enhance the function of NR1 and NR2B, which may be involved in the development of remifentanil-induced hyperalgesia in rats with IP.

Dose-effect relationship of remifentanil inhibiting responses to endotracheal intubation without neuromuscular relaxant when combined with dexmedetomidine in patients undergoing thyroid surgery / 中华麻醉学杂志

Objective:To determine the median effective dose (ED 50) and the 95% effective dose (ED 95) of remifentanil inhibiting responses to endotracheal intubation without neuromuscular relaxant when combined with dexmedetomidine in patients undergoing thyroid surgery. Methods:American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients of either sex, aged 18-64 yr, with body mass index of 18-28 kg/m 2, scheduled for elective thyroid surgery under intraoperative neuromonitoring, were enrolled in this study.Dexmedetomidine was intravenously injected in a loading dose of 0.8 μg/kg at 10 min before anesthesia induction.Anesthesia was induced by intravenously injecting midazolam 0.1 mg/kg, etomidate 0.4 mg/kg and the preset dose of remifentanil.The dose of remifentanil was determined using up-and-down sequential method.The initial dose was set at 3.7 μg/kg.The dose of remifentanil in the next case was determined according to whether responses to endotracheal intubation occurred, and the ratio between the two successive doses was 1.1.The ED 50, ED 95 and 95% confidence interval (CI) were calculated by Probit analysis. Results:when combined with dexmedetomidine for anesthesia induction, the ED 50 (95% CI) of remifentanil inhibiting responses to endotracheal intubation without neuromuscular relaxant was 3.39 (3.29-3.50) μg/kg, and the ED 95 (95% CI) was 3.52 (3.48-3.64) μg/kg. Conclusion:when combined with dexmedetomidine, the ED 50 of remifentanil inhibiting responses to endotracheal intubation without neuromuscular relaxant is 3.39 μg/kg, and the ED 95 is 3.52 μg/kg.

Efficacy of different drugs in alleviating remifentanil-induced hyperalgesia: a network meta-analysis / 中华麻醉学杂志

Objective:To systematically compare the efficacy of different drugs in alleviating remifentanil-induced hyperalgesia.Methods:Databases such as PubMed, Cochrane Library, EMBASE, Web of Science, CNKI, Wanfang Data and CBM were searched using computers from inception to May 2020.The randomized controlled trials comparing the efficacy of different intervention measures for alleviating remifentanil-induced hyperalgesia were searched.After independently identifying the literature, the two reviewers conducted data extraction and evaluated the bias of the included studies, and Stata 14.0, ADDIS 1.16.5 and R4.0.2 softwares were used to analyze the data.Results:Thirty randomized controlled trials were included in our study.Compared with placebo, 3 out of 6 drugs could alleviate remifentanil-induced hyperalgesia, and the probability order for the effect was as follows: butorphanol with MD value (95% CI)-1.50 (-2.80, -0.24), dexmedetomidine with MD value (95% CI)-1.20 (-2.40, -0.09) and ketamine with MD value (95% CI) -0.88 (-1.60, -0.16). After sensitivity analysis, the efficacy of butorphanol remained to be verified.Two drugs could decrease the dosage of opioids within 24 h after operation, and the probability order for the effect was as follows: dexmedetomidine with MD value (95% CI) -14.00 (-28.00, -0.19) and ketamine with MD value (95% CI) -9.20 (-18.00, -0.08). One drug could decrease the incidence of postoperative nausea and vomiting within 24 h after operation: dexmedetomidine with RR value (95%CI) 0.28 (0.16, 0.22). Conclusion:The results of network meta-analyses show that dexmedetomidine has the best efficacy in alleviating remifentanil-induced hyperalgesia.

Effect of remifentanil on MAPK signaling pathway during intestinal epithelial cell apoptosis induced by intestinal ischemia-reperfusion in rats / 中华麻醉学杂志

Objective:To evaluate the effect of remifentanil on mitogen-activated protein kinase (MAPK) signaling pathway during intestinal epithelial cell apoptosis induced by intestinal ischemia-reperfusion (I/R) in rats.Methods:Thirty-six clean grade healthy adult male Sprague-Dawley rats, weighing 200-250 g, aged 2 months, were divided into 3 groups ( n=12 each) by a random number table method: sham operation group (Sham group), intestinal I/R group (I/R group) and remifentanil group (R group). Intestinal I/R was produced by occlusion of superior mesenteric artery for 1 h followed by reperfusion in anesthetized rats.At 30 min before ischemia, 0.2 μg·kg -1·min -1 of remifentanil was infused intravenously for 5 min , followed by infusion of normal saline for 5 min, repeating for 3 cycles in group R. At 2 h of reperfusion, blood samples were collected from right ventricle to measure the concentration of diamine oxidase (DAO). The animals were then sacrificed and the intestinal tissues were obtained for examination of pathological changes and scored according to Chiu, for calculation of intestinal epithelial cell apoptosis rate (by TUNEL), for determination of the expression of phosphorylated extracellular signal-regulated kinase (p-ERK), phosphorylated c-Jun N-terminal kinase (p-JNK), phosphorylated p38 MAPK (p-p38 MAPK), cleaved caspase-3 and nuclear factor kappa B p65 (NF-κB p65) in nucleoprotein and for calculation of p-ERK/ERK ratio, p-JNK/JNK ratio and p-p38 MAPK/p38 MAPK ratio in the intestinal tissues. Results:Compared with group Sham, Chiu′s scores, serum DAO concentration, apoptosis rate, p-ERK/ERK ratio, p-JNK/JNK ratio and p-p38 MAPK/p38 MAPK ratio and the expression of cleaved caspase-3 and NF-κB p65 in the intestinal tissues were significantly increased in group I/R, and Chiu′s scores was increased ( P<0.05), and no significant change was found in serum DAO concentration, apoptosis rate, p-ERK/ERK ratio, p-JNK/JNK ratio, p-p38 MAPK/p38 MAPK ratio and the expression of cleaved caspase-3 and NF-κB p65 in the intestinal tissues in group R ( P>0.05). Compared with group I/R, Chiu′s scores, apoptosis rate, serum DAO concentration, p-ERK/ERK ratio and expression of cleaved caspase-3 and NF-κB p65 were significantly decreased in group R ( P<0.05). Conclusion:The mechanism by which remifentanil inhibits intestinal epithelial cell apoptosis induced by intestinal I/R is related to promoting activation of ERK in rats.

Efficacy of remazolam combined with remifentanil anesthesia for radical surgery for gastric cancer in frail aged patients / 中华麻醉学杂志

Objective:To evaluate the efficacy of remazolam combined with remifentanil anesthesia for radical surgery for gastric cancer in frail aged patients.Methods:One hundred and twenty patients of either sex, aged 65-75 yr, with body mass index 18-28 kg/m 2, with simple frailty questionnaire score 3-5 points, undergoing elective laparoscopic radical gastric cancer surgery, were divided into 3 groups ( n=40 each) according to the random number table method: propofol combined with remifentanil group (P group), low-dose remazolam combined with remifentanil group (B1 group) and high-dose remazolam combined with remifentanil group (B2 group). Induction of anesthesia was as follows: propofol 2 mg/kg was intravenously injected in group P, remazolam 6 and 12 mg·kg -1·h -1 were intravenously infused in group B1 and group B2, respectively, and alfentanil and rocuronium were intravenously injected after loss of consciousness in three groups.Anesthesia maintenance was as follows: propofol 4-12 mg·kg -1·h -1 was intravenously infused in group P, remazolam 0.5-1.0 mg·kg -1·h -1 was intravenously infused in B1 and B2 groups, remifentanil 0.05-0.20 μg·kg -1·h -1 was intravenously infused in three groups, and intravenous rocuronium was injected intermittently to maintain the BIS value at 45-55 intraoperatively.The time to loss of consciousness, recovery time of consciousness and time of tracheal extubation were recorded.The occurrence of injection pain during induction of anesthesia, intraoperative cardiovascular events, intraoperative awareness, and respiratory depression, nausea and vomiting, and drowsiness during postanesthesia care unit were recorded. Results:Compared with group P, the time to loss of consciousness was significantly prolonged, the incidence of injection pain, intraoperative hypotension and bradycardia was decreased, and the incidence of postoperative somnolence was increased in B1 and B2 groups ( P<0.05). The time to loss of consciousness was significantly shorter in group B2 than in group B1 ( P<0.05). There was no statistically significant difference in the recovery time of consciousness, time of tracheal extubation, postoperative respiratory depression and incidence of nausea and vomiting among the three groups ( P>0.05). Conclusion:Remazolam combined with remifentanil anesthesia can be safely and effectively used for radical surgery for gastric cancer in frail aged patients.

Efficacy of different dose of dexmedetomidine combined with remifentanil in colonoscopy: a randomized controlled trial.

BACKGROUND: Dexmedetomidine has advantages during colonoscopy as it allows the patient to cooperate during the procedure. Few studies examined the dexmedetomidine-remifentanil combination. This study was to evaluate the effects of different doses of the dexmedetomidine-remifentanil combination in colonoscopy. METHODS: This was a prospective trial carried out at the Fourth Hospital of Hebei Medical University between 02/2018 and 10/2018. The patients were randomized: group I (dexmedetomidine 0.2 µg·kg- 1), group II (dexmedetomidine 0.3 µg·kg- 1), and group III (dexmedetomidine 0.4 µg·kg- 1), all combined with remifentanil. The primary outcomes were the patient's body movements during the procedure and adverse events. RESULTS: Compared with at admission (T0), the SBP, HR, and RR at immediately after giving DEX (T1), at the beginning of the examination (T2), 5 min after the beginning of the examination (T3), 10 min after the beginning of the examination (T4), and at the end of the examination (T5) in the three groups were all reduced (all P < 0.05), but all were within the clinically normal range. SpO2 remained > 98% in all patients during the examination. Compared with T0, the BIS values of the three groups were decreased at T1 and T2 (all P < 0.05). There were no significant differences in BIS among the three groups (all P > 0.05). The minimum BIS value in group III was lower than in groups I and II (P < 0.05). The degree of satisfaction with the anesthesia effect was higher in groups II and III that in group I (P < 0.05). No hypotension occurred, seven patients had bradycardia, and four patients had nausea/vomiting. CONCLUSIONS: Dexmedetomidine 0.3 µg·kg- 1 combined with remifentanil was effective for colonoscopy and had few adverse reactions. Chinese Clinical Trial Registry: ChiCTR2000029105 , Registered 13 January 2020 - Retrospectively registered.

Synthesis and biological evaluation of novel quinoline-piperidine scaffolds as antiplasmodium agents.

The parasitic disease malaria places almost half of the world's population at risk of infection and is responsible for more than 400,000 deaths each year. The first-line treatment, artemisinin combination therapies (ACT) regimen, is under threat due to emerging resistance of Plasmodium falciparum strains in e.g. the Mekong delta. Therefore, the development of new antimalarial agents is crucial in order to circumvent the growing resistance. Chloroquine, the long-established antimalarial drug, still serves as model compound for the design of new quinoline analogues, resulting in numerous new active derivatives against chloroquine-resistant P. falciparum strains over the past twenty years. In this work, a set of functionalized quinoline analogues, decorated with a modified piperidine-containing side chain, was synthesized. Both amino- and (aminomethyl)quinolines were prepared, resulting in a total of 18 novel quinoline-piperidine conjugates representing four different chemical series. Evaluation of their in vitro antiplasmodium activity against a CQ-sensitive (NF54) and a CQ-resistant (K1) strain of P. falciparum unveiled highly potent activities in the nanomolar range against both strains for five 4-aminoquinoline derivatives. Moreover, no cytotoxicity was observed for all active compounds at the maximum concentration tested. These five new aminoquinoline hit structures are therefore of considerable value for antimalarial research and have the potency to be transformed into novel antimalarial agents upon further hit-to-lead optimization studies.