Catalytic Undirected Meta-Selective C-H Borylation of Metallocenes.

Metallocenes are privileged backbones in the fields of synthetic chemistry, catalysis, polymer science, etc. Direct C-H functionalization is undoubtedly the simplest approach for tuning the properties of metallocenes. However, owing to the presence of multiple identical C(sp2 )-H sites, this protocol often suffers from low reactivity and selectivity issues, especially for the regioselective synthesis of 1,3-difunctionalized metallocenes. Herein, an efficient iridium-catalyzed meta-selective C-H borylation of metallocenes is reported. With no need of preinstalled directing groups, this approach enables a rapid synthesis of various boronic esters based on benzoferrocenes, ferrocenes, ruthenocene, and related half sandwich complex. A broad range of electron-deficient and -rich functional groups are all compatible with the process. Notably, C-H borylation of benzoferrocenes takes place exclusively at the benzene ring, which is likely ascribed to the shielding effect of pentamethylcyclopentadiene. The synthetic utility is further demonstrated by easy scalability to gram quantities, the conversion of boron to heteroatoms including N3 , SePh, and OAc, as well as diverse cross-coupling reactions.

Pachymic acid modulates sirtuin 6 activity to alleviate lipid metabolism disorders.

Pachymic acid (Pac), a major bioactive constituent of Poria cocos, is an antioxidant that inhibits triglyceride (TG) accumulation. To the best of our knowledge, the present study investigated for the first time whether Pac activated sirtuin 6 (SIRT6) signaling to alleviate oleic acid (OA)-palmitic acid (PA)-induced lipid metabolism disorders in mouse primary hepatocytes (MPHs). In the present study, MPHs challenged with Pac were used to test the effects of Pac on intracellular lipid metabolism. Molecular docking studies were performed to explore the potential targets of Pac in defending against lipid deposition. MPHs isolated from liver-specific SIRT6-deficient mice were subjected to OA + PA incubation and treated with Pac to determine the function and detailed mechanism. It was revealed that Pac activated SIRT6 by increasing its expression and deacetylase activity. Pa prevented OA + PA-induced lipid deposition in MPHs in a dose-dependent manner. Pac (50 µM) administration significantly reduced TG accumulation and increased fatty acid oxidation rate in OA + PA-incubated MPHs. Meanwhile, as per the results of molecular docking and relative mRNA levels, Pac activated SIRT6 and increased SIRT6 deacetylation levels. Furthermore, SIRT6 deletions in MPHs abolished the protective effects of Pac against OA + PA-induced hepatocyte lipid metabolism disorders. The present study demonstrated that Pac alleviates OA + PA-induced hepatocyte lipid metabolism disorders by activating SIRT6 signaling. Overall, SIRT6 signaling increases oxidative stress burden and promotes hepatocyte lipolysis.

Electrochemically driven regioselective C-H phosphorylation of group 8 metallocenes.

Metallocenes are privileged backbones for synthesis and catalysis. However, the direct dehydrogenative C-H functionalization of unsymmetric metallocenes suffers from reactivity and selectivity issues. Herein, we report an electrochemically driven regioselective C-H phosphorylation of group 8 metallocenes. Mechanistic investigations indicate this dehydrogenative cross coupling occurs through an electrophilic radical substitution of the metallocene with a phosphoryl radical, facilitated by the metallocene itself. This work not only offers an efficient and divergent synthesis of phosphorylated metallocenes, but also provides a guide to interpret the reactivity and regioselectivity for the C-H functionalization of unsymmetric metallocenes.

Impact of the COVID-19 Pandemic on ST-Elevation Myocardial Infarction Management in Hunan Province, China: A Multi-Center Observational Study.

Background: This study aimed to investigate the impact of the COVID-19 pandemic on ST-segment elevation myocardial infarction (STEMI) care in China. Methods: We conducted a multicenter, retrospective cohort study in Hunan province (adjacent to the epidemic center), China. Consecutive patients presenting with STEMI within 12 h of symptom onset and receiving primary percutaneous coronary intervention, pharmaco-invasive strategy and only thrombolytic treatment, were enrolled from January 23, 2020 to April 8, 2020 (COVID-19 era group). The same data were also collected for the equivalent period of 2019 (pre-COVID-19 era group). Results: A total of 610 patients with STEMI (COVID-19 era group n = 286, pre-COVID-19 era group n = 324) were included. There was a decline in the number of STEMI admissions by 10.5% and STEMI-related PCI procedures by 12.7% in 2020 compared with the equivalent period of 2019. The key time intervals including time from symptom onset to first medical contact, symptom onset to door, door-to-balloon, symptom onset to balloon and symptom onset to thrombolysis showed no significant difference between these two groups. There were no significant differences for in-hospital death and major adverse cardiovascular events between these two groups. Conclusion: During the COVID-19 pandemic outbreak in China, we observed a decline in the number of STEMI admissions and STEMI-related PCI procedures. However, the key quality indicators of STEMI care were not significantly affected. Restructuring health services during the COVID-19 pandemic has not significantly adversely influenced the in-hospital outcomes.

Forensic application of a novel MPS-based panel (90 STRs and 100 SNPs) in a non-exclusion parentage case with three autosomal STRs incompatibilities.

In kinship tests, the investigating of the forensic STRs usually provides decisive information to resolve relationship cases. We describe a parentage case with 3 genetic incompatibilities (D6S1043, D18S51 and D2S1338) between the child and alleged parent. With 90 STR loci and 100 SNP loci, the massively parallel sequencing (MPS)-based genotyping results support the certainty of parentage, and the mismatched alleles were considered to be mutations. MPS can provide additional allele sequence structures that can be used to infer the origins of the mutations. SNPs as supplementary markers can provide effective information to give an unequivocal statement of the parentage.

H2S inhibits atrial fibrillation-induced atrial fibrosis through miR-133a/CTGF axis.

AIM: Atrial fibrillation (AF) is a common clinical arrhythmia and can cause a variety of complications. To study the therapeutic effect of H2S in atrial fibrosis and explore the important role of miR-133a, in vitro experiments in human atrial fibroblasts (HAFs) were conducted. METHODS: The fibrosis in HAFs was induced by Ang II. The expression levels of miR-133a and CTGF in HAFs were examined by qRT-PCR. The proliferation and migration of HAFs were detected by CCK-8 and cell scratch assays. The protein expressions of CTGF, collagen I, collagen III and α-SMA were detected by western blotting. The dual-luciferase reporter gene was used to detect the interaction between miR-133a and CTGF. RESULTS: The proliferation and migration of HAFs stimulated by Ang II were enhanced, the expression of miR-133a was reduced, and the levels of CTGF and fibrosis markers (collagen I, collagen III and α-SMA) were increased. Furthermore, H2S reduced fibrosis, proliferation and migration of HAFs induced by Ang II. Accordingly, overexpression of miR-133a inhibited the proliferation and migration ability on Ang II-induced HAFs, and decreased the protein expressions of related fibrosis markers and CTGF. Meanwhile, miR-133a inhibitor could reverse the inhibition effect of H2S on proliferation and migration in HAFs by Ang II-induced. By targeting CTGF, miR-133a inhibited the expression of CTGF. CONCLUSION: H2S improved myocardial cell fibrosis by significantly increasing the expression of miR-133a, and CTGF might be a potential target for miR-133a to play an important role in myocardial fibrosis.

miR-340 Exerts Suppressive Effect on Retinoblastoma Progression by Targeting KIF14.

Purpose: This work aimed to investigate the influences of microRNA-340 (miR-340) on proliferation and apoptosis of retinoblastoma (RB) cells and explore its regulatory mechanism. MATERIALS AND METHODS: miR-340 mimic and inhibitor were applied for up-regulating or inhibiting the expression of miR-340 in RB cell lines. Then, CCK-8 and AnnexinV-FITC/PI staining were used to measure cell proliferation and apoptosis, respectively. After that, luciferase assay was performed to affirm the direct targets of miR-340. Furthermore, qRT-PCR and western blotting assay were carried out to detect the levels of miR-340 and KIF14. RESULTS: Our results indicated that the miR-340 was lowly expressed in RB cell lines, and up-regulation of miR-340 can decrease the proliferation and induce the apoptosis of RB cells. Moreover, we verified that miR-340 controls KIF14 expression, either directly or through a subsequent molecular cascade, and inversely related to its expression. The results obtained from the rescue assays presented that over-expression of KIF14 reversed the miR-340-mediated inhibition on malignant phenotype of RB cells. CONCLUSIONS: Overall, we proved that miR-340 can decrease the proliferation and increase the apoptosis of RB cells, and its function in RB cells was at least partially achieved via down-regulation of KIF14, prompting that miR-340 was expected to supply a new direction for clinical therapy of RB in the future.

MicroRNA-22 inhibition prevents doxorubicin-induced cardiotoxicity via upregulating SIRT1.

Oxidative stress and cardiomyocyte apoptosis contributed to the progression of doxorubicin (Dox)-induced cardiotoxicity. Recent studies identified microRNA-22 (miR-22) as a cardiac- and skeletal muscle-enriched microRNA that functioned as a key regulator in stress-induced cardiac injury. The present study aimed to investigate the role and possible mechanism of miR-22 on Dox-induced oxidative stress and cardiomyocyte apoptosis. Mice were exposed to reduplicative injections of Dox (i.p., 4 mg/kg) weekly for consecutive 4 weeks to generate Dox-induced cardiotoxicity. Herein, we found that miR-22 level was significantly increased in murine hearts subjected to chronic Dox treatment. MiR-22 inhibition attenuated oxidative stress and cardiomyocyte apoptosis in vivo and in vitro, thereby preventing Dox-induced cardiac dysfunction. Mechanistically, we observed that miR-22 directly bound to the 3'-UTR of Sirt1 and caused SIRT1 downregulation. Conversely, miR-22 antagomir upregulated SIRT1 expression and SIRT1 inhibitor abolished the beneficial effects of miR-22 antagomir. In conclusion, miR-22 inhibition prevented oxidative stress and cardiomyocyte apoptosis via upregulating SIRT1 and miR-22 might be a new target for treating Dox-induced cardiotoxicity.

Fluorescence detection of glutathione and oxidized glutathione in blood with a NIR-excitable cyanine probe.

Cyanine has been widely utilized as a near infrared (NIR) fluorophore for detection of glutathione (GSH). However, the excitation of most of the reported cyanine-based probes was less than 800 nm, which inevitably induce biological background absorption and lower the sensitivity, limiting their use for detection of GSH in blood samples. To address this issue, here, a heptamethine cyanine probe (DNIR), with a NIR excitation wavelength at 804 nm and a NIR emission wavelength at 832 nm, is employed for the detection of GSH and its oxidized form (GSSG) in blood. The probe displays excellent selectivity for GSH over GSSG and other amino acids, and rapid response to GSH, in particular a good property for indirect detection of GSSG in the presence of enzyme glutathione reductase and the reducing agent nicotinamideadenine dinucleotide phosphate, without further separation prior to fluorescent measurement. To the best of our knowledge, this is the first attempt to explore NIR fluorescent approach for the simultaneous assay of GSH and GSSG in blood. As such, we expect that our fluorescence sensors with both NIR excitation and NIR emission make this strategy suitable for the application in complex physiological systems.

Management and Outcome of Ventricular Septal Rupture Complicating Acute Myocardial Infarction: What Is New in the Era of Percutaneous Intervention?

BACKGROUND: Postinfarction ventricular septal rupture (PI-VSR) is a rare but devastating complication of acute myocardial infarction (AMI). Risk stratification in the acute phase is crucial for decision-making, and this study analyzed the risk factors for early mortality and the effects of various management options on the outcome of PI-VSR patients in the era of percutaneous intervention. METHODS: A total of 96 patients with PI-VSR were identified and divided into an acute-phase survivor group (n = 46, survived ≥2 weeks after admission) and a nonsurvivor group (n = 50, died within 2 weeks after admission). Percutaneous closure was considered in acute-phase survivors. Patients were followed up for a mean 47 (quartiles 15-71) months by clinical visit or telephone interview. RESULTS: The overall acute-phase (i.e., < 2 weeks after the diagnosis of PI-VSR) mortality rate was 52%. Female sex and Killip Class III-IV at admission were associated with an increased risk of acute-phase death. Of the 46 patients who survived ≥2 weeks, 20 underwent interventional occlusion and the procedure was successful in 19. Percutaneous closure in the acute-phase survivor group improved the immediate (21% in-hospital mortality rate) and long-term (53% mortality) outcomes. CONCLUSIONS: Patients with PI-VSR are at a high risk of acute-phase mortality. Female sex and severe cardiac dysfunction at admission are linked with a high rate of acute-phase deaths. Percutaneous closure in acute-phase survivors results in favorable short- and long-term benefits for PI-VSR patients.

Revealing differential modules in uveal melanoma by analyzing differential networks.

The aim of the present study was to investigate differential modules (DMs) between uveal melanoma (UM) and normal conditions by examining differential networks. Based on a gene expression profile collected from the ArrayExpress database, the inference of DMs involved three steps: The first step was construction of a differential co­expression network (DCN); second, the module algorithm was adapted to identify the DMs presented in DCN; finally, the statistical significance of DMs were assessed based on the null score distribution of DMs generated using randomized networks. A DCN with 309 nodes and 3,729 edges was obtained, and 30 seed genes from the DCN were examined. Subsequently, one DM, which had 179 nodes and 3,068 edges, was investigated. By utilizing randomized networks, the P­value for DM was 0.034, therefore, the DM was statically significant between UM and baseline conditions. In conclusion, the present study successfully identified one DM in UM based on DCN and module algorithm, and this DM may be beneficial in revealing the pathological mechanism of UM and provide insight for future investigation of UM.

Study on Pharmacokinetics of Three Preparations from Levistolide A by LC-MS-MS.

A rapid sensitive analytical method was established and validated to investigate levistolide A in rat plasma by liquid chromatography-tandem mass spectrometry operated in the positive ion mode. Levistilide A (LA) and internal standard (IS) andrographolide (AD), mixed with the plasma sample, were separated on a reversed phase Spursil™ C18 5 µm column. The precursor/product transitions (m/z) were 398.5/381.3 for LA and (m/z) 368.0/351.1 for AD. The calibration curve was linear over the range from 5 to 1,250 ng/mL for oral administration and 10-4,000 for intravenous administration with a correlation coefficient (r) ≥0.9993. The lower limit of quantification was 5 ng/mL for LA in plasma. The inter- and intra-day accuracy and precision were less than ±15% of the relative standard deviation. In this study, the developed method is successfully applied to the comparative pharmacokinetic study of LA in rats after oral administration of LA alone, Rhizoma Chuanxiong, and Danggui-Shaoyao-San along with the bioavailability study of LA in rats. Our study shows that low bioavailability (7.5%) is observed after oral administration of LA. Traditional formula compatibility of Danggui-Shaoyao-San could significantly enhance LA bioavailability compared with LA alone and Rhizoma Chuanxiong.

EEN regulates the proliferation and survival of multiple myeloma cells by potentiating IGF-1 secretion.

The molecular mechanisms of multiple myeloma are not well defined. EEN is an endocytosis-regulating molecule. Here we report that EEN regulates the proliferation and survival of multiple myeloma cells, by regulating IGF-1 secretion. In the present study, we observed that EEN expression paralleled with cell proliferation, EEN accelerated cell proliferation, facilitated cell cycle transition from G1 to S phase by regulating cyclin-dependent kinases (CDKs) pathway, and delayed cell apoptosis via Bcl2/Bax-mitochondrial pathway. Mechanistically, we found that EEN was indispensable for insulin-like growth factor-1 (IGF-1) secretion and the activation of protein kinase B-mammalian target of rapamycin (Akt-mTOR) pathway. Exogenous IGF-1 overcame the phenotype of EEN depletion, while IGF-1 neutralization overcame that of EEN over-expression. Collectively, these data suggest that EEN may play a pivotal role in excessive cell proliferation and insufficient cell apoptosis of bone marrow plasma cells in multiple myeloma. Therefore, EEN may represent a potential diagnostic marker or therapeutic target for multiple myeloma.

Determination and pharmacokinetics of amygdalin in rats by LC-MS-MS.

A sensitive and specific liquid chromatography-tandem mass spectrometric (LC-MS-MS) method was developed for the determination and pharmacokinetics of amygdalin in rats. Rat plasma pretreated by solid-phase extraction was analyzed by LC-MS-MS with negative electrospray ionization in the multiple reaction monitoring mode. Amygdalin and geniposide [the internal standard (IS)] were separated on a C18 column eluted with a mobile phase of methanol and water (85:15; v/v) at a flow rate of 0.25 mL/min in a run time of 3.0 min. The precursor to product ion transitions were monitored at m/z 457.2 → 279.1 for amygdalin and m/z 387.1 → 224.9 for the IS. The calibration curve of amygdalin showed good linearity over a concentration range of 10-2,000 ng/mL. The limit of quantification was 10 ng/mL. Intra-day and inter-day precisions and accuracy (percent relative standard deviation) were both within 10%. The method was fully validated for its selectivity, sensitivity, matrix effect, recovery and stability. This accurate and specific assay produced a useful LC-MS-MS method, which was successfully applied to pharmacokinetic studies after the oral administration of amygdalin to rats.

[Gene detection of GPD1-L and the association with sudden unexplained death syndrome in young adults].

OBJECTIVE: To analyze the variations of glycerol-3-phosphate dehydrogenase 1 like gene (GPD1-L) and address the association with sudden manhood death syndrome (SMDS). METHODS: The genomic DNA was extracted from blood samples of the SMDS group and the normal control group. The exons, exon-intron boundaries and 3'-UTRs of coding region of GPD1-L were PCR amplified and DNA sequenced directly to confirm the types of variations. The genotype frequency and allele frequency were analyzed statistically. RESULTS: There were two variants in the SMDS group, c.465C>T and c.*18G>T, the latter existed certain degree difference of genotype distribution and allele frequency between the SMDS group and the control group, but there was no statistically significant (P > 0.05). CONCLUSION: The relation between gene mutation of GPD1-L and the occurrence of Chinese SMDS deserves a further research.

A novel fluorescent probe for selective detection of thiols in acidic solutions and labeling of acidic organelles in live cells.

A novel fluorescent probe, quinoline α,ß-unsaturated diacid (QMA), as compared to its ester QME, was constructed and can selectively detect thiols in acidic solutions (pH < 7) via a H-bond activated Michael addition. Furthermore, labeling of lysosomes and cell imaging were achieved by the detection of biothiols in different domains of live cells.

[The anti-portal hypertension effect of oleanolic acid in CCl4-induced cirrhosis rats].

OBJECTIVE: To study the anti-portal hypertension effect of oleanolic acid (OA) in CCl4-induced cirrhosis rats and its mechanism. METHODS: Rats were induced to portal hypertension by CCl4. After treatment with low dose of OA (30 mg/kg) and high dose of OA (60 mg/kg) by intragastrically for a month, the parameters in serum or liver tissue including ALT, AST, MDA, GSH-Px, NOx, eNOS, cGMP and type I collagen were measured. The MAP, PP and HR were determined by hameodynamic method and the eNOS expression in liver was measured by western blot. The pathological changes of liver tissue were also tested by Masson dye. The normal group and model group were given 0.25% of CMC-Na solution. RESULTS: Compared with the model group, treatment with 30 mg/kg and 60 mg/kg OA significantly decreased the levels of ALT, AST, ALP, gamma-GT and MDA and enhanced the level of GSH-Px in liver (P<0.05). Moreover, the collagen content also notably lowered in CCl4-induced cirrhosis rats, thus decreasing the portal pressure (PP). However, the MAP and HR were not affected by OA treatment. In addition, the expression of eNOS in liver markedly increased after one mouth treatment of OA, hereof enhancing the level of cGMP and NOx in the CCl4-induced portal hypertensive rats (P<0.05). CONCLUSION: OA could inhibit the progress of fibrosis and lower the PP in CCl4-induced portal hypertensive rats and the anti-portal hypertension effect might be related to increasing the expression of eNOS and enhance the NOx level in liver.

Simultaneous determination of esculin and its metabolite esculetin in rat plasma by LC-ESI-MS/MS and its application in pharmacokinetic study.

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method operated in the negative electrospray ionization (ESI) switching mode has been developed and validated for the simultaneous determination of esculin and its metabolite esculetin in rat plasma. After addition of internal standards scopoletin, the plasma sample was pretreated by solid-phase extraction (SPE), and separated on a reversed phase C(18) column with a mobile phase of 0.01% formic acid in water (solvent A) and methanol (solvent B) using isocratic elution (A:B=20:80, v/v). The detection of target compounds was done in multiple reaction monitoring (MRM) mode. The MRM detection was operated in the negative ESI mode using the transitions of m/z 339.1 ([M-H](-))→176.7 for esculetin, m/z 176.9 ([M-H](-))→133.0 and m/z 191.0 ([M-H](-))→175.9 for scopoletin. The standard curves, which ranged from 25 to 3200 ng/mL for esculin with the lowest limit of quantification (LLOQ) of 0.25 ng/mL and from 1.25 to 160 ng/mL for esculetin with the LLOQ of 1.25 ng/mL, were fitted to a 1/x weighted quadratic regression model. The method also afforded satisfactory results in terms of the sensitivity, specificity, precision (intra- and inter-day, RSD<8.73%), accuracy, recovery as well as the stability of the analyte under various conditions. The method was successfully applied to study the pharmacokinetics of esculin and its metabolite esculetin in rat plasma after oral administration of esculin at a dose of 100mg/kg.

Determination of geniposidic acid in rat plasma by LC-MS/MS and its application to in vivo pharmacokinetic studies.

A simple, rapid and sensitive method for the determination of geniposidic acid (GSA) in rat plasma was developed using liquid chromatography tandem mass spectrometry (LC-MS/MS). Geniposide (GS) was used as the internal standard. Rat plasma pretreated by solid-phase extraction (SPE) was analyzed by LC-MS/MS with negative ion mode electrospray ionization (ESI) in the multiple reaction monitoring (MRM) mode. The analytical column was C8 column and the mobile phase was methanol (A) and water (B). The flow rate was set at 0.8 mL/min with split ratio of 1:3, the total run time was 15 min. The MS/MS ion transitions monitored were m/z 373.3-211.1 for GSA and m/z 387.3-225.3 for GS. The quantification limit was 5 ng/mL within a linear range of 10-4000 ng/mL. The inter-day and intra-day accuracy and precision were within ±10%. The method was fully validated for its sensitivity, selectivity, matrix effect, stability study and recovery. The data indicate that our LC-MS/MS assay is an effective method for the pharmacokinetics study of GSA in rat plasma.

[Genetic polymorphisms of 18 STR loci in Uygur population of Kashi Prefecture of Xinjiang].

OBJECTIVE: To investigate the genetic polymorphisms of 18 STR loci (D18S51, D21S11, D3S1358, FGA, D8S1179, upsilonWA, CSF1PO, D16S539, D7S820, D13S317, D5S818, D2S1338, D19S433, D12S391, TPOX, TH01, Penta E and D6S1043) in unrelated Uygur individuals in Kashi prefecture of Xinjiang and to explore the application value in forensic practice. METHODS: Blood samples from 1 381 unrelated Uygur individuals were amplified by using DNA Typer 15 Plus kit. The amplified products were detected by using 3130XL Genetic Analyzer and the genotyping was done by using GeneMapper ID v3.2. Population genetics parameters were calculated and compared with that of the other population. The genetic distance of Reynold's was calculated and phylogenetic tree was constructed at last. RESULTS: Of the 1 381 unrelated Uygur individuals, 231 alleles were detected, with an allele frequency of 0.0004-0.5304. The H values were 0.644-0.923, PIC values were 0.587-0.918, and DP values were 0.817-0.988, respectively, with a CPE > 0.9999999. The genetic distance was the longest (0.088 3) to Guangzhou Han population and the closest (0.0503) to Greek. CONCLUSION: The 18 STR loci in the Uygur population of Kashi prefecture of Xinjiang have high genetic polymorphisms which are close to Europeans, and can be satisfied as genetic markers of population individual identification and paternity testing.