Electrocatalytic Reduction of CO2 to CO by Molecular Cobalt-Polypyridine Diamine Complexes.

Cobalt complexes have previously been reported to exhibit high faradaic efficiency in reducing CO2 to CO. Herein, we synthesized capsule-like cobalt-polypyridine diamine complexes [Co(L1)](BF4)2 (1) and [Co(L2) (CH3CN)](BF4)2 (2) as catalysts for the electrocatalytic reduction of CO2. Under catalytic conditions, complexes 1 and 2 demonstrated the electrocatalytic reduction of CO2 to CO in the presence or absence of CH3OH as a proton source. Experimental and computational studies revealed that complexes 1 and 2 undergo two consecutive reversible one-electron reductions on the cobalt core, followed by the addition of CO2 to form a metallocarboxylate intermediate [CoII(L)-CO22-]0. This crucial reaction intermediate, which governs the catalytic cycle, was successfully detected using high resolution mass spectrometry (HRMS). In situ Fourier-transform infrared spectrometer (FTIR) analysis showed that methanol can enhance the rate of carbon-oxygen bond cleavage of the metallocarboxylate intermediate. DFT studies on [CoII(L)-CO22-]0 have suggested that the doubly reduced species attacks CO2 on the C atom through the dz2 orbital, while the interaction with CO2 is further stabilized by the π interaction between the metal dxz or dxz orbital with p orbitals on the O atoms. Further reductions generate a metal carbonyl intermediate [CoI(L)-CO]+, which ultimately releases CO.

Re-analysis of hepatitis B virus integration sites reveals potential new loci associated with oncogenesis in hepatocellular carcinoma.

BACKGROUND: Hepatitis B virus (HBV) is a major cause of hepatocellular carcinoma (HCC). HBV DNA can get integrated into the hepatocyte genome to promote carcinogenesis. However, the precise mechanism by which the integrated HBV genome promotes HCC has not been elucidated. AIM: To analyze the features of HBV integration in HCC using a new reference database and integration detection method. METHODS: Published data, consisting of 426 Liver tumor samples and 426 paired adjacent non-tumor samples, were re-analyzed to identify the integration sites. Genome Reference Consortium Human Build 38 (GRCh38) and Telomere-to-Telomere Consortium CHM13 (T2T-CHM13 (v2.0)) were used as the human reference genomes. In contrast, human genome 19 (hg19) was used in the original study. In addition, GRIDSS VIRUSBreakend was used to detect HBV integration sites, whereas high-throughput viral integration detection (HIVID) was applied in the original study (HIVID-hg19). RESULTS: A total of 5361 integration sites were detected using T2T-CHM13. In the tumor samples, integration hotspots in the cancer driver genes, such as TERT and KMT2B, were consistent with those in the original study. GRIDSS VIRUSBreakend detected integrations in more samples than by HIVID-hg19. Enrichment of integration was observed at chromosome 11q13.3, including the CCND1 pro-moter, in tumor samples. Recurrent integration sites were observed in mitochondrial genes. CONCLUSION: GRIDSS VIRUSBreakend using T2T-CHM13 is accurate and sensitive in detecting HBV integration. Re-analysis provides new insights into the regions of HBV integration and their potential roles in HCC development.

Preparation and Properties of Polyvinylpyrrolidone/Sodium Carboxymethyl Cellulose Soluble Microneedles.

Transdermal drug delivery is a new means of delivering drugs through the skin to achieve therapeutic effects. Microneedles have several advantages, including low cost, easy self-administration, and high delivery efficiency. Different polymers affect the morphology, mechanical properties, and drug delivery efficiency of microneedles. To study the performance and limitations of microneedles (MNs), we prepared different ratios of polymers. MNs were fabricated from polyvinylpyrrolidone (PVP) and sodium carboxymethyl cellulose (CMC-Na) using the centrifugal molding method. Needle morphology, formability, and other properties of the polymers were evaluated to compare the performances of MNs with different ratios. PVP and CMC-Na were intermixed at different ratios with water as the solvent. The soluble MNs were prepared by mold casting. The morphology, thermodynamic properties, and crystallinity were studied using scanning electron microscopy (SEM), thermogravimetric analysis (TG), differential scanning calorimetric analysis (DSC), and X-ray diffraction (XRD). The results showed that composite microneedles have good thermal stability. Among the different compositions tested, the 10% PVP/2% CMC-Na composite microneedle demonstrated the best performance with a regular surface morphology and relatively high thermal decomposition and melting temperatures. These results indicate that microneedles with appropriate ratios of two different materials possess good formability and other properties.

Alteration of the tumor microenvironment by pharmacological inhibition of EZH2 in hepatocellular carcinoma.

Enhancer of zeste homolog 2 (EZH2), a core component of polycomb repressive component 2 is overexpressed in a variety of cancers and recognized as a therapeutic target molecule. However, EZH2 possesses immunomodulatory functions in the tumor microenvironment (TME). The impact of EZH2 on TME of hepatocellular carcinoma (HCC) using immunocompetent mouse model was evaluated in the present study. UNC1999, an EZH2 inhibitor, impaired growth of the murine HCC cells (H22 cells) and induced apoptosis in a dose-dependent manner. Although UNC1999 significantly inhibited the growth of H22 cells-derived and Hepa1-6 cells-derived tumors in nonobese diabetic/severe combined immunodeficiency mice, its antitumor effect was diminished in allogenic BALB/c and C57BL/6 mice. Flow cytometric analyses of TME cells in BALB/c mice demonstrated a significant decrease in the number of interferon­Î³+ CD8+ T cells and regulatory T cells and a significant increase in the number of myeloid-derived suppressor cells (MDSCs). Administration of Gr-1 neutralizing antibody concomitant with UNC1999 restored antitumor effect accompanied by an increase in the number of CD8+ T cells followed by a decrease in the number of MDSCs. Chemokine antibody array demonstrated an enhanced expression of chemokines responsible for MDSCs recruitment such as C5a, CCL8, and CCL9. In conclusion, the study results demonstrated that EZH2 inhibitor contributed to attenuation of tumor immunity caused by TME arrangement. Combination therapy with EZH2 inhibitors and agents that reduce MDSCs might represent a novel therapeutic strategy for HCC.

Miglustat, a glucosylceramide synthase inhibitor, mitigates liver fibrosis through TGF-ß/Smad pathway suppression in hepatic stellate cells.

Transforming growth factor (TGF)-ß/Smad pathway is implicated in the pathogenesis of liver fibrosis, a condition characterized by excessive deposition of extracellular matrix (ECM) proteins such as collagen in response to chronic inflammation. It has been reported that ceramide regulates collagen production through TGF-ß/Smad pathway activation. In this study, we examined whether miglustat, an inhibitor of glucosylceramide synthase, can suppress liver fibrosis by reducing TGF-ß/Smad pathway activity. Human hepatic stellate cells (HHSteCs) were cultured with TGF-ß and multiple miglustat concentrations to examine dose-dependent effects on the expression levels of ECM-related genes and Smad proteins. To evaluate the efficacy of miglustat for fibrosis mitigation, C57BL/6 mice were treated with carbon tetrachloride (CCl4) for 4 weeks to induce liver fibrosis, followed by combined CCl4 plus miglustat for a further 2 weeks. To examine if miglustat can also prevent fibrosis, mice were treated with CCl4 for 2 weeks, followed by CCl4 plus miglustat for 2 weeks. Miglustat dose-dependently downregulated expression of α-smooth muscle actin and ECM components in TGF-ß-treated HHSteCs. Both phosphorylation and nuclear translocation of Smad2 and Smad3 were also suppressed by miglustat treatment. Sirius-Red staining and hydroxyproline assays of model mouse liver samples revealed that miglustat reduced fibrosis, an effect accompanied by decreased expression of ECM. Our findings suggest that miglustat can both prevent and reverse liver fibrosis by inhibiting TGF-ß/Smad pathway.

Antiviral Compounds Screening Targeting HBx Protein of the Hepatitis B Virus.

A functional cure of hepatitis B virus (HBV) infection or HB antigen loss is rarely achieved by nucleos(t)ide analogs which target viral polymerase. HBx protein is a regulatory protein associated with HBV replication. We thought to identify antiviral compounds targeting HBx protein by analyzing HBx binding activity. Recombinant GST-tagged HBx protein was applied on an FDA-approved drug library chip including 1018 compounds to determine binding affinity by surface plasmon resonance imaging (SPRi) using a PlexArray HT system. GST protein alone was used for control experiments. Candidate compounds were tested for anti-HBV activity as well as cell viability using HepG2.2.15.7 cells and HBV-infected human hepatocytes. Of the 1018 compounds screened, 24 compounds showed binding to HBx protein. Of the top 6 compounds with high affinity to HBx protein, tranilast was found to inhibit HBV replication without affecting cell viability using HepG2.2.15.7 cells. Tranilast also inhibited HBV infection using cultured human hepatocytes. Tranilast reduced HB antigen level dose-dependently. Overall, theSPRi screening assay identified novel drug candidates targeting HBx protein. Tranilast and its related compounds warrant further investigation for the treatment of HBV infection.

Effect of Atezolizumab plus Bevacizumab in Patients with Hepatocellular Carcinoma Harboring CTNNB1 Mutation in Early Clinical Experience.

Atezolizumab plus bevacizumab (ATZ/BV) treatment is a combined immunotherapy consisting of immune checkpoint inhibitor (ICI) and anti-vascular endothelial growth factor monoclonal antibody, which has brought a major paradigm shift in the treatment of unresectable hepatocellular carcinoma (HCC). Gain-of-function mutation of CTNNB1 contributes to resistance of ICI monotherapy through the framework of non-T-cell-inflamed tumor microenvironment. However, whether CTNNB1 mutation renders resistance to ATZ/BV similar to ICI monotherapy remains to be elucidated. In this study, a liquid biopsy sample in plasma of 33 patients with HCC treated with ATZ/BV was subjected to droplet digital PCR for detecting hotspot mutations at the exon 3 of CTNNB1 locus. A total of eight patients (24.2%) exhibited at least one CTNNB1 mutation. The objective response rate (ORR) in patients with wild-type (WT) and mutant (MT) CTNNB1 was 8.0% and 12.5%, respectively, and the disease control rate (DCR) was 68.0% and 87.5%, respectively. No significant difference in both ORR and DCR has been observed between the two groups. The median progression-free survival in patients with WT and MT CTNNB1 was 6.6 and 7.6 months, respectively (not statistically significant). Similarly, no significant difference in overall survival has been observed between patients with WT and MT CTNNB1 (13.6 vs. 12.3 months). In conclusion, the treatment effect of ATZ/BV in patients with HCC with MT CTNNB1 was comparable to those patients with WT CTNNB1. These results implicate that BV added to ATZ might improve immunosuppressive tumor microenvironment caused by CTNNB1 mutation.

Electrospun Fibers Derived from Peptide Coupled Amphiphilic Copolymers for Dorsal Root Ganglion (DRG) Outgrowth.

Developing scaffolds with appropriate mechanical/structural features as well as tunable bioactivities are indispensable in the field of tissue engineering. This study focused on one such attempt to electrospin the copolymer of L-lactic acid (L-LA) and functional monomer (3(S)- [(benzyloxycarbony)methyl]-1,4-dioxane-2,5-dione, BMD) with small peptide modifications for the purpose of neural tissue engineering. Scanning Electron Microscopy (SEM) micrographs showed fabricated electrospun copolymer as porous and uniform nanofibrous materials with diameter in the range of 800-1000 nm. In addition, the modified scaffolds displayed a lower contact angle than poly(L-lactide) (PLLA) indicating higher hydrophilicity. To further incorporate the bioactive functions, the nanofibers were chemically coupled with small peptide (isoleucine-lysine-valine-alanine-valine, IKVAV). The incorporation of IKVAV onto the electrospun fiber was confirmed by X-ray photoelectron spectroscopy (XPS) and such incorporation did not affect the surface morphology or fiber diameters. To demonstrate the potential of applying the designed scaffolds for nerve regeneration, dorsal root ganglion (DRG) neurons were cultured on the nanofibers to examine the impact on neurite outgrowth of DRGs. The results indicated that the fabricated nanofibrous matrix with small peptide might be a potential candidate for neural tissue engineering.

Serum Angiopoietin 2 acts as a diagnostic and prognostic biomarker in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is typically accompanied by abundant arterial blood flow. Although angiogenic growth factors such as Angiopoietin 2 (Ang2) play a central role in tumor angiogenesis in HCC, the role of serum Ang2 as a biomarker in HCC remains unclear. In this study, we aimed to investigate the potential of Ang2 as a diagnostic and prognostic biomarker in HCC using a sandwich enzyme-linked immunosorbent assay (ELISA). The median Ang2 levels in controls (n=20), chronic liver disease patients (n=98), and HCC patients (n=275) were 1.58, 2.33, and 3.53 ng/mL, respectively. The optimal cut-off value of Ang2 was determined as 3.5 ng/mL by receiver operating curve analysis. The sensitivity, specificity, and accuracy of Ang2 for HCC detection were 50.9, 83.7, and 59.5%, respectively. Spearman's rank correlation coefficient analysis demonstrated only a weak correlation between Ang2 serum levels and alpha-fetoprotein (AFP) or des-gamma-carboxy prothrombin (DCP) serum levels. The diagnostic value of Ang2 was comparable to those of other existing markers. In addition, 24 out of 73 patients with normal AFP and DCP levels (32.9%) demonstrated abnormally high Ang2 levels (≥3.5 ng/mL). Although no significant difference in overall survival was found between Ang2high and Ang2low patients with curative ablation therapy, recurrence-free survival (RFS) in Ang2high patients was observed to be significantly shorter than those in Ang2low patients. Multivariate analysis demonstrated that high serum Ang2 levels (≥3.5 ng/mL) and the presence of multiple tumors were poor prognostic factors. In conclusion, our findings indicate that serum Ang2 is a potential novel biomarker for both diagnosis and prognosis in HCC.

Acquisition of mesenchymal-like phenotypes and overproduction of angiogenic factors in lenvatinib-resistant hepatocellular carcinoma cells.

Lenvatinib is one of the first-line drugs for patients with advanced hepatocellular carcinoma (HCC) and widely used around the world. However, the mechanisms underlying resistance to lenvatinib remain unclear. In this study, we conducted characteristic analyses of lenvatinib-resistant HCC cells. Lenvatinib-resistant HCC cell lines were established by exposure to serially escalated doses of lenvatinib over 2 months. The biological characteristics of these cells were examined by in vitro assays. To investigate the cytokine profile of lenvatinib-resistant HCC cells, the supernatant derived from lenvatinib-resistant Huh7 cells was subjected to nitrocellulose membrane-based sandwich immunoassay. Both activation of the MAPK/MEK/ERK signaling pathway and upregulation of epithelial mesenchymal transition markers were observed in lenvatinib-resistant cells. Concordant with these findings, proliferation and invasion abilities were enhanced in these cells compared with control cells. Screening of a cytokine array spotted with 105 different antibodies to human cytokines enabled us to identify 16 upregulated cytokines in lenvatinib-resistant cells. Among them, 3 angiogenic cytokines: vascular endothelial growth factor (VEGF), platelet-derived growth factor-AA (PDGF-AA), and angiogenin, were increased significantly. Conditioned medium from lenvatinib-resistant cells accelerated tube formation of human umbilical vein cells. In conclusion, lenvatinib-resistant HCC cells were characterized by enhanced proliferation and invasion abilities. These findings might contribute to the establishment of new combination therapies with lenvatinib.

Synthesis of functional polyester for fabrication of nano-fibrous scaffolds and its effect on PC12 cells.

An ideal scaffold should mimic the advantageous characteristics of a natural extracellular matrix for cell attachment, proliferation, and differentiation. In this study, well-defined block copolymer with functional groups was synthesized. The structure of the block copolymer was characterized by nuclear magnetic resonance, gel permeation chromatography, and differential scanning calorimetry. Thermally induced phase separation was employed to fabricate nano-fibrous scaffolds based on the synthesized block copolymer. The scaffold, with fiber diameter ranging from 400 to 500 nm, was fabricated for in vitro culture of PC12 cells. The carboxyl groups on the side chain resulted in increased hydrophilicity of nano-fibrous scaffolds and enhanced cell proliferation. In addition, this scaffold structure was beneficial in directing the growth of regenerating axons in nerve tissue engineering. Results of 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay and scanning electron microscopy confirmed that the nano-fibrous scaffolds with functional groups were suitable for PC12 cells growth. Moreover, the carboxyl groups were suitable for coupling with biological signals. Thus, the nano-fibrous scaffolds have potential applications in tissue engineering.

Investigation and Intervention of Mental Health State of Clinical Trainees in the Hospital of Yuxi City / 昆明医科大学学报

Objective Investigate and intervene the psychological health state of clinical trainees in the hospital of Yuxi City, in order to explore the method to improve the psychological health and clinical quality of teaching. Methods From 2009 to 2013, clinical trainees were investigated by SCL-90. Intervention for interns included holding psychological health lectures and making psychological counseling for the serious interns. At the same time, the teachers were trained to carry out two-way intervention between the teachers and clinic interns and to improve clinical interns' psychological health. Results Before the intervention,among 216 interns,34 (15.74%) showed positive. Except fear factor, other factors were significantly different than national norms ( <0.05). After the intervention, among 149 interns, 20 ( 13.42%) showed positive. Obsessive-compulsive symptom, depression,anxiety,hostility, spirit factors and the mean scores were all lower than before ( <0.05),similar to the national norm.Conclusion Clinical trainees have prominent psychological problems. Teaching hospitals should pay more attention to psychological health of them. Intervention is necessary and effective in improving psychological health and quality of teaching.

Using genipin-crosslinked acellular porcine corneal stroma for cosmetic corneal lens implants.

Acellular porcine corneal stroma (APCS) has been proven to maintain the matrix microenvironment and is therefore an ideal biomaterial for the repair and reconstruction of corneal stroma. This study aims to develop a method to prepare cosmetic corneal lens implants for leukoma using genipin-crosslinked APCS (Gc-APCS). The Gc-APCS was prepared from APCS immersed in 1.0% genipin aqueous solution (pH 5.5) for 4 h at 37 °C, followed by lyophilization at -10 °C. The color of the Gc-APCS gradually deepened to dark-blue. The degree of crosslinking was 45.7 ± 4.6%, measured by the decrease of basic and hydroxy amino acids. The porous structure and ultrastructure of collagenous lamellae were maintained, and the porosity and BET SSA were 72.7 ± 4.6% and 23.01 ± 3.45 m(2)/g, respectively. The Gc-APCS rehydrated to the physiological water content within 5 min and was highly resistant to collagenase digestion. There were no significant differences in the areal modulus and curvature variation between Gc-APCS and nature porcine cornea. The dark-blue pigments were stable to pH, light and implantation in vivo. Gc-APCS extracts had no inhibitory effects on the proliferation of keratocytes. Corneal neovascularization, graft degradation and corneal rejection were not observed within 6 months.

Elastic chitosan conduits with multiple channels and well defined microstructure.

Four kinds of chitosan conduits with longitudinal multi-channels and controlled internal microstructures were prepared using a special mold and a freeze-drying method. One of the conduits was fabricated from a chitosan solution (ab NC), while the other three groups were made from a pre-gelled chitosan solution using genipin as a chemical cross-linker (ab gNC), dibasic sodium phosphate as a physical cross-linker (ab pNC) or a combined ionic and covalent co-cross-linker (ab gpNC), respectively. The porosity of the chitosan conduits ranged from 88 to 90%. The gpNC showed highly interconnected and uniformly distributed pores compared to NC, the gNC and pNC. In contrast, the gNC and gpNC showed about 10% of the volume swelling ratio in 37°C PBS solution, although the gpNC scaffold's water uptake was the highest, at more than 17 times its original mass. Compressive tests showed that gpNC had significant elasticity and maintained its physical integrity even after compressing them down to 20% of their original height. The elastic modulus of gpNC reached 80 kPa, which was more than twice that of the other groups. Adhesion and proliferation of PC12 cells on chitosan gpNC scaffolds showed excellent properties by MTT and SEM observation, which indicated the potential of gpNC scaffolds for nerve tissue engineering applications.

Operation of Decompression and Internal Fixation from the Posterior Approach for Treating Multiple Levels Spinal Instability complicated with Spinal Cord Injury / 中国医师杂志

Objective To study the treatment techniques of multiple levels spinal instability complicated with spinal cord injury induced by various factors using opertation of decompression and internal fixation from the posterior approach, and observe their effects. Methods 69 cases of multiple levels spinal instability complicated with spinal cord injury resulting from the acute fractures of violent force, the chronic multiple levels vertebral cavity stenosis and congenital cervical vertebral deformity were treated with the techniques mentioned above. All the patients were followed up for 1 to 3 years after operation. The injury degree of spinal cord was graded according to ASIA's standards before and after operation, and operative efficacy was evaluated. Results 52 cases completely recovered, 9 mostly recovered, and 4 went about on crutches. Among 2 cases of paralysis patients, 1 still was complete paralysis and the other one died. The total efficacious rate was 88%. Conclusion Operation of decompression and internal fixation was effective for treating multiple levels spinal instability, especially for complicated with an incomplete spinal cord injury.