Gelation Behavior and Drug Sustained-Release Properties of a Helix Peptide Organohydrogel with pH Responsiveness.

Based on the typical similar repeat units (abcdefg)n of α-helical structure, the peptide H was designed to self-assemble into an organohydrogel in response to pH. Depending on the different pH, the proportions of secondary structure, microstructure, and mechanical properties of the gel were investigated. Circular dichroism (CD) and Fourier transform infrared (FT-IR) showed that the proportion of α-helical structure gradually increased to become dominant with the increase of pH. Combining transmission electron microscopy (TEM) and atomic force microscopy (AFM), it was found that the increase of the ordered α-helix structure promoted fiber formation. The further increase in pH changed the intermolecular forces, resulting in an increase in the α-helix content and the enhancement of helix-helix interaction, causing the gel fibers to converge into thicker and more dense ones. The temperature test showed the stable rheological properties of the organohydrogel between 20-60 °C. Drug release and cytotoxicity showed that the DOX-loaded organohydrogel could have a better release in an acidic environment, indicating its potential application as a drug local delivery carrier.

Photochemical Difluoromethylation of Quinoxalin-2(1H)-ones with Difluoroacetic Anhydride and Pyridine N-Oxide.

A novel photochemical difluoromethylation of quinoxalin-2(1H)-ones under catalyst-free conditions was achieved with difluoroacetic anhydride and pyridine N-oxide. The green and mild reaction conditions as well as readily attainable difluoroacetic anhydride provide a useful protocol to prepare C3-difluoromethylated quinoxalin-2(1H)-ones.

Photochemical alkylation of quinoxalin-2(1H)-ones with N,N,N',N'-tetraalkylethylenediamine.

A visible-light-induced C-3 alkylation of quinoxalin-2(1H)-ones with N,N,N',N'-tetraalkylethylenediamine was achieved without an external photocatalyst. The mechanism showed that quinoxalin-2(1H)-ones could act as photocatalysts. The accessibility of the reagents and the green and mild reaction conditions made this protocol an alternative method to access C-3 alkylated quinoxalin-2(1H)-ones.

Photochemical tandem reaction of nitrogen containing heterocycles, bicyclo[1.1.1]pentane, and difluoroiodane(III) reagents.

A visible light-induced difluoroalkylation/heteroarylation of [1.1.1]propellane with nitrogen containing heterocycles and difluoroiodane(III) reagents was achieved. Various heteroarenes and difluoroiodane(III) reagents exhibited good compatibility, yielding the desired products in moderate to good yields. The accessibility of the reagents and the mild reaction conditions establish this method as an alternative and practical strategy for accessing diverse 1-difluoroalkyl-3-heteroaryl bicyclo[1.1.1]pentanes (BCPs).

Copper-catalyzed thiocyanation of cyclobutanone oxime esters using ammonium thiocyanate.

A copper-catalyzed thiocyanation of cycloketone oxime esters with ammonium thiocyanate has been developed for the first time. This innovative approach allows access to cyano and thiocyano bifunctionally substituted alkanes, which can be further transformed into their respective trifluoromethylthiol-substituted or difluoromethylthiol-substituted alkylnitriles, alkynyl sulfides, and phosphorothioate esters. The readily available nature of ammonium thiocyanate and the cost-effectiveness of the copper catalyst make this method a promising strategy for the synthesis of sulfur-containing alkylnitriles.

Visible-light-induced tandem reaction of quinoxalin-2(1H)-ones, alkenes, and sulfonyl chlorides.

A visible-light-induced tandem reaction involving quinoxalin-2(1H)-ones, alkenes, and sulfonyl chlorides, catalyzed by 4CzIPN, was developed. The utilization of easily accessible sulfonyl chlorides, metal-free conditions, and a wide substrate scope established this protocol as an efficient and alternative method for obtaining sulfonated quinoxalin-2(1H)-ones.

Double pyramid stacked CoO nano-crystals induced by graphene at low temperatures as highly efficient Fenton-like catalysts.

Transition metal oxides are widely used as Fenton-like catalysts in the treatment of organic pollutants, but their synthesis usually requires a high temperature. Herein, an all-solid-state synthesis method controlled by graphene was used to prepare a double pyramid stacked CoO nano-crystal at a low temperature. The preparation temperature decreased by 200 °C (over 30% reduction) due to the introduction of graphene, largely reducing the reaction energy barrier. Interestingly, the corresponding degradation rate constants (kobs) of this graphene-supported pyramid CoO nano-crystals for organic molecules after their adsorption were over 2.5 and 35 times higher than that before adsorption and that of free CoO, respectively. This high catalytic efficiency is attributed to the adsorption of pollutants at the surface by supporting graphene layers, while free radicals activated by CoO can directly and rapidly contact and degrade them. These findings provide a new strategy to prepare low carbon-consuming transition metal oxides for highly efficient Fenton-like catalysts.

Mechanisms and influencing factors of peptide hydrogel formation and biomedicine applications of hydrogels.

Self-assembled peptide-based hydrogels have shown great potential in bio-related applications due to their porous structure, strong mechanical stability, high biocompatibility, and easy functionalization. Herein, the structure and characteristics of hydrogels and the mechanism of action of several regular secondary structures during gelation are investigated. The factors influencing the formation of peptide hydrogels, especially the pH responsiveness and salt ion induction are analyzed and summarized. Finally, the biomedical applications of peptide hydrogels, such as bone tissue engineering, cell culture, antigen presentation, antibacterial materials, and drug delivery are reviewed.

Visible-Light-Promoted Trifluoromethylthiolation and Trifluoromethylselenolation of 1,4-Dihydropyridines.

We report a metal-free trifluoromethylthiolation and trifluoromethylselenolation of 1,4-dihydropyridines with S-(trifluoromethyl) 4-methylbenzenesulfonothioate and Se-(trifluoromethyl) 4-methylbenzenesulfonoselenoate under visible light irradiation. This transformation was tolerated with a wide range of functional groups and provided an alternative and green strategy for the synthesis of trifluoromethylthioesters and trifluoromethylselenoesters.

Visible-Light-Induced Difluoroalkylation of Alkenes and Alkynes with Fluoro-Containing Hypervalent Iodane (III) Reagents Under Photo-Catalyst-Free Conditions.

A visible-light-induced difluoroalkylation of unactivated alkenes by fluoro-containing hypervalent iodine-based difluoroalkylation reagent was achieved for the first time under photo-catalyst-free conditions. Moreover, the same reaction conditions were applicable to the difluoroalkylation of alkynes to give the hydrodifluoroalkylation products in moderate to excellent yields. The readily available reagent, broad substrate scope, and photo-catalyst-free conditions make this protocol an efficient and environmental friendly method for the hydrodifluoroalkylation of alkenes and alkynes.

Association between serum iron, blood lead, cadmium, mercury, selenium, manganese and low cognitive performance in old adults from National Health and Nutrition Examination Survey (NHANES): a cross-sectional study.

Cognitive decline is a public health problem for the world's ageing population. This study was to evaluate the relationships between serum Fe, blood Pb, Cd, Hg, Se and Mn and cognitive decline in elderly Americans. Data of this cross-sectional study were extracted from the National Health and Nutritional Examination Survey (NHANES 2011-2014). Cognitive performance was measured by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Animal Fluency and Digit Symbol Substitution Test (DSST) tests. Weighted univariable and multivariate logistic regression analyses were used to assess the associations between six trace elements and low cognitive performance. Subgroup analyses based on diabetes and hypertension history were further assessed the associations. A total of 2002 adults over 60 years old were included. After adjusting covariates, elevated serum Fe levels were associated with the decreased risk of low cognitive performance, especially in the elderly without diabetes history and with hypertension history. High blood Cd levels were associated with the high odds of low cognitive performance in old adults with diabetes and hypertension history. Elevated blood Mn levels were connected with low cognitive performance in old hypertensive people. High blood Pb levels were related to the high odds of low cognitive performance, especially in the elderly without diabetes and hypertension history. High blood Se levels were linked to the decreased risk of low cognitive performance in all the elderly. Appropriate Fe, Se supplementation and Fe-, Se-rich foods intake, while reducing exposure to Pb, Cd and Mn may be beneficial for cognitive function in the elderly.

Copper-catalyzed ring-opening trifluoromethylthiolation/trifluoromethylselenolation of cyclopropanols with TsSCF3 or Se-(trifluoromethyl) 4-methoxybenzenesulfonoselenoate.

We report a ring-opening trifluoromethylthiolation of cyclopropanols with TsSCF3 by using Cu(OAc)2 as the catalyst. Moreover, by using this strategy, the trifluoromethylselenolation of cyclopropanols with Se-(trifluoromethyl) 4-methoxybenzenesulfonoselenoate to access ß-SeCF3-substituted carbonyl compounds is achieved for the first time. The broad substrate scope, readily accessible reagents and cheap catalyst make this protocol an alternative and efficient method for the synthesis of ß-SCF3-substituted or ß-SeCF3-substituted carbonyl compounds.

Visible-light promoted cascade cyanoalkylsulfonylation/ipso-cyclization of N-arylpropiolamides toward sulfonated spiro[4,5]trienones via SO2 insertion.

A novel visible-light induced sulfonylation/ipso-cyclization of N-arylpropiolamides with cyclobutanone oxime esters and Na2S2O5 was reported. This protocol proceeded via a radical process. The wide substrate scope, sustainable metal-free conditions and readily accessible reagents make this protocol an efficient and green strategy for the synthesis of cyanoalkyl sulfonated spiro[4,5]trienones.

The predictive value of CD4, CD8, and C-reactive protein in the prognosis of schistosomal and non-schistosomal colorectal cancer.

BACKGROUND: Although schistosomiasis has been basically eliminated, it has not been completely extinction in China and occasional outbreaks occur in Europe in recent years. The relationship between inflammation caused by Schistosoma japonicum and colorectal cancer (CRC) is still obscure, and the inflammation based prognostic systems of schistosomal colorectal (SCRC) has rarely been reported. AIM: To explore the different roles of tumor infiltrating lymphocytes (TILs) and C-reactive protein (CRP) in SCRC and in Non-schistosomal CRC (NSCRC), providing a possible predictive system to evaluate outcomes and to improve the risk stratification for CRC patients, especially for CRC patients with schistosomiasis. METHODS: Three hundred fifty-one CRC tumors were evaluated for density of CD4 + , CD8 + T cells and CRP in intratumoral and stromal compartments by immunohistochemical using tissue microarray. RESULTS: There were no association between TILs and CRP and schistosomiasis. Multivariate analysis identified stromal CD4 (sCD4) (p = 0.038), intratumoral CD8 (iCD8) (p = 0.003), schistosomiasis (p = 0.045) as independent prognostic factors for overall survival (OS) in the whole cohort; and sCD4 (p = 0.006) and iCD8 (p = 0.020) were independent prognostic factors for OS in the NSCRC and SCRC set, respectively. Besides, we found that there were no differences of TILs and CRP, which were distributed in different areas of tumor tissue, between CRC patients with and without schistosomiasis. CONCLUSION: The results remind us that different subtypes of TILs have distinguished biological behavior and prognosis value in the immune microenvironment of NSCRC and SCRC patients. Meanwhile, the findings require us to stratify patients with schistosomiasis and this might facilitate patient counseling and management.

Comparison of the prognostic value of stromal tumor-infiltrating lymphocytes and CD3 + T cells between schistosomal and non-schistosomal colorectal cancer.

AIM: To compare the prognostic value of tumor-infiltrating lymphocytes (TILs) and CD3 + cells and CD20 + cells between schistosomal colorectal cancer (SCRC) and non-schistosomal CRC (NSCRC). BACKGROUND: Although schistosomiasis has been basically eliminated, it has not been completely extinction in China, and occasional outbreaks occur in Europe recently. The role of immune cells in the immune microenvironment of SCRC and NSCRC is remaining obscure, and the inflammation-based prognostic systems of SCRC has rarely been reported. METHODS: HE-stained sections of 349 colorectal cancer (CRC) tumors, which were completely resected, were evaluated for density of TILs. Meanwhile, we evaluated CD3 + T lymphocytes and CD20 + B lymphocytes by immunochemistry. The relationship of these infiltrating immune cells with clinicopathological features, including schistosomiasis, and clinical outcomes was evaluated, and the prognostic roles of TILs in SCRC and NSCRC were explored. RESULTS: Except for age (P < 0.0001), there were no significant differences between NSCRC and SCRC patients in clinicopathological features (P > 0.05). Beside, the positive expression pattern of sTILs, iTILs, CD3, and CD20 between NSCRC and SCRC patients was also similar (P > 0.05). In the whole cohort, sTILs and CD3 were defined as independent prognostic factors (P = 0.031 and P = 0.003, respectively). CD3 was an independent prognostic factor both in the NSCRC and SCRC set (P = 0.026 and P = 0.045, respectively). Higher sTILs, CD3, and CD20 were correlated with less aggressive tumor characteristics in the whole cohort and in subgroups. CONCLUSION: Although CD3 was an independent prognostic factor for both NSCRC and SCRC set, there were no significant differences between SCRC and NSCRC patients in sTILs, CD3, CD20, and in other clinicopathological features.

Synthesis, molecular docking, and binding Gibbs free energy calculation of ß-nitrostyrene derivatives: Potential inhibitors of SARS-CoV-2 3CL protease.

The outbreak of novel coronavirus disease 2019 (COVID-19), caused by the novel coronavirus (SARS-CoV-2), has had a significant impact on human health and the economic development. SARS-CoV-2 3CL protease (3CLpro) is highly conserved and plays a key role in mediating the transcription of virus replication. It is an ideal target for the design and screening of anti-coronavirus drugs. In this work, seven ß-nitrostyrene derivatives were synthesized by Henry reaction and ß-dehydration reaction, and their inhibitory effects on SARS-CoV-2 3CL protease were identified by enzyme activity inhibition assay in vitro. Among them, 4-nitro-ß-nitrostyrene (compound a) showed the lowest IC50 values of 0.7297 µM. To investigate the key groups that determine the activity of ß-nitrostyrene derivatives and their interaction mode with the receptor, the molecular docking using the CDOCKER protocol in Discovery Studio 2016 was performed. The results showed that the hydrogen bonds between ß-NO2 and receptor GLY-143 and the π-π stacking between the aryl ring of the ligand and the imidazole ring of receptor HIS-41 significantly contributed to the ligand activity. Furthermore, the ligand-receptor absolute binding Gibbs free energies were calculated using the Binding Affinity Tool (BAT.py) to verify its correlation with the activity of ß-nitrostyrene 3CLpro inhibitors as a scoring function. The higher correlation(r2=0.6) indicates that the absolute binding Gibbs free energy based on molecular dynamics can be used to predict the activity of new ß-nitrostyrene 3CLpro inhibitors. These results provide valuable insights for the functional group-based design, structure optimization and the discovery of high accuracy activity prediction means of anti-COVID-19 lead compounds.

In vitro and in vivo evaluation of DC-targeting PLGA nanoparticles encapsulating heparanase CD4+ and CD8+ T-cell epitopes for cancer immunotherapy.

Heparanase has been identified as a universal tumor-associated antigen, but heparanase epitope peptides are difficult to recognize. Therefore, it is necessary to explore novel strategies to ensure efficient delivery to antigen-presenting cells. Here, we established a novel immunotherapy model targeting antigens to dendritic cell (DC) receptors using a combination of heparanase CD4+ and CD8+ T-cell epitope peptides to achieve an efficient cytotoxic T-cell response, which was associated with strong activation of DCs. First, pegylated poly(lactic-coglycolic acid) (PLGA) nanoparticles (NPs) were used to encapsulate a combined heparanase CD4+ and CD8+ T-cell epitope alone or in combination with Toll-like receptor 3 and 7 ligands as a model antigen to enhance immunogenicity. The ligands were then targeted to DC cell-surface molecules using a DEC-205 antibody. The binding and internalization of these PLGA NPs and the activation of DCs, the T-cell response and the tumor-killing effect were assessed. The results showed that PLGA NPs encapsulating epitope peptides (mHpa399 + mHpa519) could be targeted to and internalized by DCs more efficiently, stimulating higher levels of IL-12 production, T-cell proliferation and IFN-γ production by T cells in vitro. Moreover, vaccination with DEC-205-targeted PLGA NPs encapsulating combined epitope peptides exhibited higher tumor-killing efficacy both in vitro and in vivo. In conclusion, delivery of PLGA NP vaccines targeting DEC-205 based on heparanase CD4+ and CD8+ T-cell epitopes are suitable immunogens for antitumor immunotherapy and have promising potential for clinical applications.

Design, synthesis and properties of peptide inhibitors based on BRCA1856-871.

Overexpression of RAD51 protein was found to increase drug resistance in breast cancer cells. Breast cancer susceptibility gene 1 (BRCA1) protein can specifically bind to RAD51 protein and regulate the expression level of RAD51 protein. Based on previous studies, eight modified peptides were obtained by modifying the N-terminus of the key peptide segment 856-871 of BRCA1 with nicotinic acid (NA) and its derivatives. The interaction of BRCA1856-871 and modified peptides with the RAD51158-180 target peptide was investigated by fluorescence and circular dichroism spectroscopies. The results showed that the binding ability of 2-TFM-NA-PP to RAD51158-180 was significantly enhanced. BRCA1856-871 and modified peptides were studied by in vitro cell experiments. The results showed that the antitumor activity of 5-TFM-NA-PP was significantly enhanced compared with BRCA1856-871.

Visible-Light-Promoted Selenocyanation of Cyclobutanone Oxime Esters Using Potassium Selenocyanate.

We report the visible-light-promoted selenocyanation of cyclobutanone oxime esters using potassium selenocyanate in the presence of a fac-Ir(ppy)3 catalyst for the first time. Because of the mild conditions employed and use of readily accessible potassium selenocyanate, this method is an effective and green strategy for the synthesis of cyano and selenocyano bifunctional substituted alkanes.

Metal-Free Trifluoromethylthiolation of Arylazo Sulfones.

A visible-light-driven protocol for the synthesis of aryl trifluoromethyl thioethers under photocatalyst- and metal-free conditions has been pursued. The procedure exploits the peculiar properties of arylazo sulfones (having electron-rich or electron-poor substituents on the (hetero)aromatic ring) as photochemical precursors of aryl radicals and S-trifluoromethyl arylsulfonothioates as easy-to-handle trifluoromethylthiolating agents.