Mechanism and Origin of MAD-Induced Ni/N-Heterocyclic Carbene-Catalyzed Regio- and Enantioselective C-H Cyclization of Pyridines with Alkenes

This work presents a DFT-based computational study on the regio- and enantioselective C-H functionalization of pyridines with alkenes at the relatively unreactive C4-position, which was successfully achieved by Shi et al. [J. Am. Chem. Soc. 2019, 141, 5628-5634] using Ni⁰ /N-heterocyclic carbene (NHC) catalysis under the assistance of an aluminum-based Lewis acid additive (2,6-tBu₂ -4-Me-C₆ H₂ O)₂ AlMe (MAD). The calculations indicate that the selective functionalization involves a three-step mechanism in which a unique H-migration assisted oxidation metalation (HMAOM) step is identified as the rate- and enantioselectivity-determining step. The newly proposed mechanism can well rationalize the experimental observation that the preferred product is the endo-type (vs. exo-type), R-configuration (vs. S-configuration) product at the C4 (vs. C2) position, and also unveil the reasons that the NHC ligand and the MAD additive can facilitate the reaction.

Redox deracemization of β,γ-alkynyl α-amino esters

The first non-enzymatic redox deracemization method using molecular oxygen as the terminal oxidant has been described. The one-pot deracemization of β,γ-alkynyl α-amino esters consisted of a copper-catalyzed aerobic oxidation and chiral phosphoric acid-catalyzed asymmetric transfer hydrogenation with excellent functional group compatibility. By using benzothiazoline as the reducing reagent, an exclusive chemoselectivity at the C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> N bond over the C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> C bond was achieved, allowing for efficient deracemization of a series of α-amino esters bearing diverse α-alkynyl substituent patterns. The origins of chemo- and enantio-selectivities were elucidated by experimental and computational mechanistic investigation. The generality of the strategy is further demonstrated by efficient deracemization of β,γ-alkenyl α-amino esters.

A one-pot deracemization of β,γ-alkynyl α-amino esters consisting of an aerobic oxidation and chiral phosphoric acid-catalyzed asymmetric transfer hydrogenation has been described.

Polyketides from the endolichenic fungus Eupenicillium javanicum and their anti-inflammatory activities

Seven undescribed polyketides javanicols A-E, 5-epi-citreoviridin and 5-epi-isocitreoviridin, together with five known compounds, were isolated from the endolichenic fungus Eupenicillium javanicum. The structures of these polyketides were determined by means of extensive spectroscopic analyses, electronic circular dichroism (ECD) calculations and gauge-independent atomic orbital (GIAO) NMR shift calculations. These compounds were evaluated for potential anti-inflammatory activity against LPS-activated RAW 264.7 cells. Javanicol E and (+)-terrein displayed moderate inhibitory effects on NO production, with IC₅₀ values of 17.00 and 13.46 μM, respectively.

δ-Cyano substituted para-quinone methides enable access to unsymmetric tri- and tetraarylmethanes containing all-carbon quaternary stereocenters

Placing an electron-withdrawing cyano group into the δ-position of para-quinone methides enables facile access to unsymmetrical tri- and tetraarylmethanes bearing all-carbon quaternary stereocenters.

[A Chinese consensus statement on the clinical application of transesophageal echocardiography for critical care (2019)]

Transesophageal echocardiography(TEE) is valuable in intensive care unit (ICU) because its application meets the requirements of diagnosis and treatment of critically ill patients.However, the current application has not fully adapted to the specialty of critical care. TEE could be more valuablein ICU when used with a new way that under the guidance of the theory of critical care and embedded into the treatment workflow. We have expanded and improved the application of traditional TEE and integrated the concept of critical care, established the concept of transesophageal echocardiography for critical care (TEECC). Chinese Critical Ultrasound Study Group (CCUSG) organized experts in the area to form the consensus based the previous studiesand the long term practice of critical care ultrasound and TEE, aiming at clarifying the nature and characteristics of TEECC, promoting the rational and standardized clinical application and the coming researches.The consensus of Chinese experts on clinical application of TEECC (2019) were 33 in total, of whichthe main items were as follows: (1) TEECC is a significant means, which is expanded and improved from the traditional transesophageal echocardiography according to characteristics of critically ill patients and is applied in ICU based on critically clinical scenarios and requirements by the critical care physician, to promote visualized, refined and precisely management of critically ill patients.(2) TEE possesses distinctive superiority in implementation in ICU. It has characteristics of images with good quality, operations with good stability and low-dependent of operators, monitoring with continuity, and visualization with all-dimensional and detail of heart and blood vessels.(3)As a means of refined monitoring that could resulted in precise diagnosis and treatment, TEECC expands the dimension of intensive monitoring and improves the performance of critical care. (4) Indications of TEECC application include clinical etiological searching and invasive procedures guiding when it acted as a traditional role; and also refined hemodynamic monitoring based on critical care rationale and over-all management under specific critical clinical scenarios. (5) TEE and TTE assessments are complementary; they are not alternative. Integrated assessment of TTE and TEE is required under many critical clinical scenarios.(6) TEE should be a necessary configuration in ICU. (7) All-round and significant information regarding to the mechanism of acute circulatory disorders can be provided by TEECC; it is a non-substitutable means of identifying the causes of shock under some special clinical scenarios. (8) Focal extracardiac hematoma can be accurately and rapidly detected by TEE in patients with open-thoracic cardiac surgery or severe chest trauma when highly suspected pericardial tamponade.(9) The priority of pathophysiologic mechanism of septic shock can be rapidly and accurately identified by TEE; even if its pathophysiological changes are complex, including hypovolemia and/or vasospasm and/or left and right heart dysfunction. (10) Causes of hemodynamic disorders can be rapidly and qualitatively evaluated so that the orientation of treatment can be clarified by TEECC. (11) A full range of quantitative indicators for refined hemodynamic management in critically ill patients can be provided by TEECC. (12) TEECC helps to accurately assess volume status and predict fluid responsiveness.(13) TEECC is specially suitable for accurate quantitative assessment of cardiac function.(14) Mini TEE provides long-term continuous hemodynamic monitoring. (15) Standard views are easy to be acquired by TEECC, which is a premise for accurate and repeatable measurements, and a guarantee for assessment of effect and risk of therapy. (16) Compared with invasive hemodynamic monitoring, TEECC is minimally invasive, with low infection risk and high safety.(17) In patients with acute cor pulmonale (ACP) under condition of right ventricular dysfunction and low cardiac output, TEECC is a key tool for assessment. (18) TEECC should be implemented actively when suspicious of left to right shunt in critically ill patients who occurred hypotension that hard to explain the cause. (19) TEECC should be implemented actively when suspicious of right to left shunt in critically ill patients who occurred hypoxemia that hard to explain the cause. (20) TEECC is preferred in hemodynamics monitoring under prone position of ventilated patients.(21) TEECC is an imperative means to achieve over-all management of extracorporeal membrane oxygenation (ECMO) therapy, especially for all-round hemodynamic monitoring. (22) Three basic views is recommended to be used to simplify TEE assessment during cardiac arrest so that reversible causes could be identified, and resuscitation could be guided. (23) The flow related echodynamic evaluation (TEECC-FREE) workflow is preferred in refined hemodynamics monitoring and therapy. (24) Simple workflow of TEECC could be implemented in special critical clinical scenarios. (25) Application of TEECC is highly secure; however, impairments of procedure should also be alert by operators. (26) Pitfalls in application of TEE should be paid attention to by the critical care physician. (27) Timely and rationally application of TEECC is in favor of diagnosis and treatment of critically ill patients and may improve the prognosis.

Direct Oxidative Dearomatization of Indoles with Aromatic Ketones: Rapid Access to 2,2-Disubstituted Indolin-3-ones

A metal-free oxidative dearomatization of indoles with aromatic ketones mediated by TEMPO oxoammonium salt is described. The dearomatization proceeds smoothly and displays a broad substrate scope with respect to both indoles and aromatic ketones in the presence of H2SO4, affording the corresponding 2,2-disubstituted indolin-3-ones in good yields.

[Effect of clinical characteristics on relapse of alcohol dependence: a prospective cohort study]

OBJECTIVE

To investigate whether craving and demographic factors to predict relapse in alcohol dependence.

METHODS

This study was a prospective cohort study. From August 2017 to August 2018, 158 Han male inpatients who met the diagnositic and statistical manual disorders-fourth version(DSM-IV) alcohol dependence diagnostic criteria were recruited from three mental hospitals in China. The participants were interviewed at baseline and followed up by telephone after 3 months for assessment. The baseline assessment after the acute withdrawal period included demographic data and alcohol-related data, clinical institute withdrawal assessment-advanced revised (CIWA-Ar), withdrawal and cue-induced craving on visual analog scale (VAS), Michigan alcoholism screening test (MAST), self-rating anxiety scale (SAS), self-rating depression scale (SDS) and alcohol urge questionnaire (AUQ). According to the follow-up results, "relapse" was defined as the consumption of beverages containing ethanol at any time during the follow-up study, and "time to relapse" was defined as the number of days from the first drinking to the baseline. Whether relapse occurred and the time to relapse were the primary endpoints. Cox proportional hazard regression model was used to analyze the factors affecting the relapse of alcohol dependence.

RESULTS

In the study, 158 alcohol dependence patients were finally included, age from 21 to 60 years, with the mean age of (40.31±9.14) years. The relapse rate was 63.7% three months after baseline assessment. According to Cox univariate analysis and multivariate analysis, the age (OR=0.975, P=0.030) and CIWA-Ar scores (OR=1.126, P=0.010) significantly predicted relapse. And there was no significant difference in education level, marital status, withdrawal and cue-induced craving on VAS, SAS and SDS between the relapse group and the non-relapse group (P>0.05).

CONCLUSION

Age and severity of alcohol-dependent withdrawal symptoms during hospitalization are significantly related to relapse for alcohol in alcohol-dependent patients. To be exact, the older age is a protective factor, that is to say, the younger patients are prone to relapse, while the risk of relapse is raised by the higher severity of withdrawal symptoms. However, neither cue-induced nor withdrawal craving can predict relapse of alcohol-dependent patients.

Theoretical Insight into the Mechanism and Origin of Divergent Reactivity in the Synthesis of Benzo-Heterocycles from o-Alkynylbenzamides Catalyzed by Gold and Platinum Complexes

This work presents a DFT study on the mechanism and origin of catalyst-controlled divergent reactivity in the synthesis of benzo-heterocycles from o-alkynylbenzamides by Au(I)/Pt(IV) catalysis. The results indicate that the transformations proceed via a nucleophilic cyclization process. In the Au(I) catalysis, the preferred O-attack mode mainly originates from the symmetry match in the dominant bond-forming interaction between the lone-pair orbital of carbonyl-O and the in-plane alkyne π* orbital, and the electronic property of the ligand controls the O-5-exo-dig/O-6-endo-dig selectivity. The preference for the N-attack mode in Pt(IV) catalysis is attributed to the stronger coordinate capability of carbonyl-O than amino-N in the substrate to PtCl₄, and the regioselective N-6-endo-dig or N-5-exo-dig cyclization depends on the stronger electrostatic interaction between the amino-N and alkynyl-C_β atoms. The theoretical results provide a fundamental understanding of why and how gold and platinum complexes catalyze the cyclization of o-alkynylbenzamides with different chemo- and regioselectivities.

Correction to: Rehmanniae Radix Preparata suppresses bone loss and increases bone strength through interfering with canonical Wnt/β-catenin signaling pathway in OVX rats

There was a mistake in the part of OVX rats model and RRP intervention in the original publication.

Sacculatane diterpenoids from the Chinese liverwort Pellia epiphylla with protection against H2O2-induced apoptosis of PC12 cells

Eight previously undescribed sacculatane diterpenoids, epiphyllins A-H, and one unknown bibenzyl-based isopentene along with seven known compounds were isolated from the Chinese liverwort Pellia epiphylla (L.) Corda. Their structures were established unequivocally on the basis of spectroscopic data and CD measurement. The quinine reductase-inducing activity evaluation demonstrated that epiphyllins A-D, 1β-hydroxysacculatanolide and pellianolactone B displayed moderate antioxidant effect. Further investigation of pellianolactone B revealed its protective effects on H₂O₂-induced oxidative insults and apoptosis in PC12 cells.

[A reevaluation of diagnostic efficacy of International Society of Thrombosis and Haemostasis and Japanese Association for Acute Medicine criteria for the diagnosis of sepsis disseminated intravascular coagulation]

Objective: To reevaluate the diagnostic efficacy of International Society of Thrombosis and Haemostasis (ISTH) and Japanese Association for Acute Medicine (JAAM) criteria for sepsis disseminated intravascular coagulation (DIC). Methods: A total of 769 patients diagnosed as sepsis were enrolled in our study. Blood samples were collected within the first hour in ICU and the index of coagulation was detected. The correlation between the conventional coagulation index and the acute physiology and chronic health evaluation (APACHE Ⅱ) and sequential organ failure assessment (SOFA) scores was analyzed. The sensitivity and specificity of diagnostic efficacy were analyzed by receiver operating characteristic (ROC) curve. Results: In the 769 cases, 95 cases (12.35%) conformed to the standard of ISTH and 271 cases (35.24%) were in accordance with the standard of JAAM. Prolonged prothrombin time (PT) was seen in 726 cases (94.41%). Activated partial thromboplastin time (APTT) was prolonged in 434 cases (56.44%). Plasma fibrinogen (Fib) was decreased in 94 cases (12.22%) and increased in 365 cases(47.46%). Platelet (PLT) count decreased in 158 cases (20.55%). D-dimer was elevated in 759 cases (98.70%). Fibrin degradation product (FDP) was increased in 724 cases (94.15%). PT, APTT, D-dimer, FDP, PLT were correlated with APACHE Ⅱ(r value were 0.259, 0.348, 0.319, 0.289,-0.275, all P values<0.05) and SOFA score(r values were 0.409, 0.445, 0.407, 0.411,-0.526, respectively, all P values<0.05). The areas under the curve (AUCs) in the ISTH standard from high to low were accordingly PT (0.813), FDP (0.792), PLT (0.746), Fib (0.563). The AUCs from high to low were FDP (0.844), PLT (0.716), and PT (0.660), respectively in the JAAM standard. Under the criteria of ISTH, the diagnostic sensitivities of PT, PLT, Fib and FDP were 92.63%, 67.37%, 9.47%, 98.95%, respectively, and specificities as 53.56%, 86.05%, 99.26% and 33.38%% respectively. As to the JAAM criteria, the diagnostic sensitivities of PT, PLT, and FDP were 74.54%, 52.77%, 91.51% and specificities as 51.61%, 84.94%, 40.76% respectively. Conclusions: According to the ISTH and JAAM diagnostic criteria, the diagnostic efficacy of PT and PLT is relatively high, which is associated with the severity of DIC. D-dimer and FDP have the high sensitivity but the specificity is poor. The diagnostic specificity of Fib is good, yet with low sensitivity and poor overall efficacy.

Elevated aspartate aminotransferase and monocyte counts predict unfavorable prognosis in patients with malignant pleural mesothelioma

Limited biomarkers predicting prognosis of malignant pleural mesothelioma (MPM) have been identified. The present study aims to assess potential laboratory prognostic factors of MPM. We retrospectively reviewed the clinical data of 105 patients with MPM. The overall survival and prognostic factors were assessed by Kaplan-Meier curves and Cox regression analysis. A receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off values. The mean age of the 105 patients (62 men, 43 women) was 56.0 years. The major clinical presentations were dyspnea, cough and chest pain. The most common laboratory abnormalities were thrombocytosis and elevated monocyte count. Significant prognostic factors on univariate analysis were performance status (PS), serum albumin, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), monocyte, platelet to lymphocyte ratio (PLR), lymphocyte to monocyte ratio (LMR) and treatment strategy. Multivariate analysis showed PS, AST, monocyte, and treatment strategy were statistically significant (p<0.05). Higher AST level and monocyte count were both related to the presence of anemia (p=0.001 and 0.010, respectively) and higher ALP level (p=0.049 and 0.001, respectively). A higher AST level was also associated with higher alanine aminotransferase (ALT) and LDH level (p<0.05). A higher monocyte count was also correlated with male patients, higher white blood cell (WBC), platelet, neutrophil counts, lower red blood cell (RBC) and LMR counts (p<0.05). In conclusion, our data show that PS<2, normal AST level, lower monocyte count, and multimodality treatment are independent positive prognostic factors of MPM. The elevated AST and monocyte levels represent unfavorable prognostic biomarkers of MPM.

Rehmanniae Radix Preparata suppresses bone loss and increases bone strength through interfering with canonical Wnt/β-catenin signaling pathway in OVX rats

Rehmanniae Radix Preparata (RRP) improves bone quality in OVX rats through the regulation of bone homeostasis via increasing osteoblastogenesis and decreasing osteoclastogenesis, suggesting it has a potential for the development of new anti-osteoporotic drugs.

INTRODUCTION

Determine the anti-osteoporotic effect of RRP in ovariectomized (OVX) rats and identify the signaling pathway involved in this process.

METHODS

OVX rats were treated with RRP aqueous extract for 14 weeks. The serum levels of tartrate-resistant acid phosphatase (TRAP), receptor activator of nuclear factor kappa-Β ligand (RANKL), alkaline phosphatase (ALP), and osteoprotegerin (OPG) were determined by ELISA. Bone histopathological alterations were evaluated by H&E, Alizarin red S, and Safranin O staining. Bone mineral density (BMD) and bone microstructure in rat femurs and lumbar bones were determined by dual-energy X-ray absorptiometry and micro-computed tomography. Femoral bone strength was detected by a three-point bending assay. The expression of Phospho-glycogen synthase kinase 3 beta (p-GSK-3β), GSK-3β, Dickkopf-related protein 1 (DKK1), cathepsin K, OPG, RANKL, IGF-1, Runx2, β-catenin, and p-β-catenin was determined by western blot and/or immunohistochemical staining.

RESULTS

Treatment of OVX rats with RRP aqueous extract rebuilt bone homeostasis demonstrated by increasing the levels of OPG as well as decreasing the levels of TRAP, RANKL, and ALP in serum. Furthermore, RRP treatment preserved BMD and mechanical strength by increasing cortical bone thickness and epiphyseal thickness as well as improving trabecular distribution in the femurs of OVX rats. In addition, RRP downregulated the expression of DKK1, sclerostin, RANKL, cathepsin K, and the ratio of p-β-catenin to β-catenin, along with upregulating the expression of IGF-1, β-catenin, and Runx2 and the ratio of p-GSK-3β to GSK-3β in the tibias and femurs of OVX rats. Echinacoside, jionoside A1/A2, acetoside, isoacetoside, jionoside B1, and jionoside B2 were identified in the RRP aqueous extract.

CONCLUSION

RRP attenuates bone loss and improves bone quality in OVX rats partly through its regulation of the canonical Wnt/β-catenin signaling pathway, suggesting that RRP has the potential to provide a new source of anti-osteoporotic drugs.