Dental restorative materials with antimicrobial properties can inhibit bacterial colonization, which may result in a reduction of caries at tooth-filling interaction zones. This study aimed to develop antibacterial gl...Dental restorative materials with antimicrobial properties can inhibit bacterial colonization, which may result in a reduction of caries at tooth-filling interaction zones. This study aimed to develop antibacterial glass-ionomer cements (GIC) containing a quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM), and to investigate their effect on material performance and antibacterial properties. Different mass fractions (0, 1.1% and 2.2%) of DMADDM were incorporated into the GIC. The flexure strength, surface charge density, surface roughness and fluoride release were tested. A Streptococcus mutans biofilm model was used. Exopolysaccharides (EPS) staining was used to analyze the inhibitory effect of DMADDM on the biofilm matrix. In addition, biofilm metabolic activity, lactic acid metabolism and the expression of glucosyltransferase genes g/fB, gtfC and gtfD were measured. GIC containing 1.1% and 2.2% DMADDM had flexural strengths matching those of the commercial control (P〉0.1). DMADDM was able to increase the surface charge density but reduced surface roughness (P〈0.05). The incorporation of 1.1% and 2.2% DMADDM elevated the release of fluoride by the GIC in the first 2 days (P〈0.05). The novel DMADDM-modified GIC significantly reduced biofilm metabolic activity (P〈 0.05) and decreased lactic acid production (P〈 0.05). The quantitative polymerase chain reaction (qPCR) results showed that the expression of gtfB, g/fC and gtfD decreased when mass fractions of DMADDM increased (P〈0.05). EPS staining showed that both the bacteria and EPS in biofilm decreased in the DMADDM groups. The incorporation of DMADDM could modify the properties of GIC to influence the development of S. mutans biofilms. In this study, we investigated the interface properties of antibacterial materials for the first time. GIC containing DMADDM can improve material performance and antibacterial properties and may contribute to the better management of secondary caries.展开更多
Melanoma is the most aggressive form of skin cancer.Disrupted intracellular signaling pathways are responsible for melanoma's extraordinary resistance to current chemotherapeutic modalities. The pathophysiologic b...Melanoma is the most aggressive form of skin cancer.Disrupted intracellular signaling pathways are responsible for melanoma's extraordinary resistance to current chemotherapeutic modalities. The pathophysiologic basis for resistance to both chemo- and radiation therapy is rooted in altered genetic and epigenetic mechanisms that, in turn, result in the impairing of cell death machinery and/or excessive activation of cell growth and survival-dependent pathways. Although most current melanoma therapies target mitochondrial dysregulation,there is increasing evidence that endoplasmic reticulum(ER) stress-associated pathways play a role in the potentiation,initiation and maintenance of cell death machinery and autophagy. This review focuses on the reliability of ER-associated pathways as therapeutic targets for melanoma treatment.展开更多
In addition to its contributing role in the development of chronic liver diseases, chronic hepatitis C virus(HCV) infection is associated with extrahepatic manifestations, particularly, cutaneous-based disorders inclu...In addition to its contributing role in the development of chronic liver diseases, chronic hepatitis C virus(HCV) infection is associated with extrahepatic manifestations, particularly, cutaneous-based disorders including those with pruritus as a symptom. Pruritus is frequently associated with the development of chronic liver diseases such as cholestasis and chronic viral infection, and the accumulation of bile acids in patients' sera and tissues as a consequence of liver damage is considered the main cause of pruritus. In addition to their role in dietary lipid absorption, bile acids can trigger the activation of specific receptors, such as the G protein-coupled bile acid receptor(GPBA/ TGR5). These types of receptors are known to play a crucial role in the modulation of the systemic actions of bile acids. TGR5 expression in primary sensory neurons triggers the activation of the transient receptor potential vanilloid 1(TRPV1) leading to the induction of pruritus by an unknown mechanism. Although the pathologic phenomenon of pruritus is common, there is no uniformly effective therapy available. Understanding the mechanisms regulating the occurrence of pruritus together with the conduction of large-scale clinical and evidence-based studies, may help to create a standard treatment protocol. This review focuses on the etiopathogenesis and treatment strategies of pruritus associated with chronic HCV infection.展开更多
High-quality DNA extraction is a crucial step in metagenomic studies.Bias by different isolation kits impairs the comparison across datasets.A trending topic is,however,the analysis of multiple metagenomes from the sa...High-quality DNA extraction is a crucial step in metagenomic studies.Bias by different isolation kits impairs the comparison across datasets.A trending topic is,however,the analysis of multiple metagenomes from the same patients to draw a holistic picture of microbiota associated with diseases.We thus collected bile,stool,saliva,plaque,sputum,and conjunctival swab samples and performed DNA extraction with three commercial kits.For each combination of the specimen type and DNA extraction kit,20-gigabase(Gb)metagenomic data were generated using short-read sequencing.While profiles of the specimen types showed close proximity to each other,we observed notable differences in the alpha diversity and composition of the microbiota depending on the DNA extraction kits.No kit outperformed all selected kits on every specimen.We reached consistently good results using the Qiagen QiAamp DNA Microbiome Kit.Depending on the specimen,our data indicate that over 10 Gb of sequencing data are required to achieve sufficient resolution,but DNA-based identification is superior to identification by mass spectrometry.Finally,longread nanopore sequencing confirmed the results(correlation coefficient>0.98).Our results thus suggest using a strategy with only one kit for studies aiming for a direct comparison of multiple microbiotas from the same patients.展开更多
The micro- and nanostructures of human dental enamel were investigated by transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). For this purpose, TEM slices were prepared from teeth b...The micro- and nanostructures of human dental enamel were investigated by transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). For this purpose, TEM slices were prepared from teeth by focused ion-beam milling. These slices enabled TEM and transmission-EBSD (t-EBSD) investigations to be performed, while standard EBSD on bulk tooth samples resulted only in Kikuchi patterns. On the TEM slices, t-EBSD enabled automated mapping. The TEM images and the EBSD data dearly elucidated the arrangement of the hydroxyapatite crystals on the nanometer scale. Information regarding the crystallographic orientation of the apatite grains enabled the deduction of novel nanotechnological building principles of the enamel structure based on a chain-like arrangement of the crystallites.展开更多
基金supported by a National Natural Science Foundation of China grant 81372889 (Lei Cheng), 81430011 (Xue-dong Zhou)the Program for New Century Excellent Talents in University (Lei Cheng)+3 种基金a Youth Grant of the Science and Technology Department of Sichuan Province, China 2014JQ0033 (Lei Cheng)the International Science and Technology Cooperation Program of China 2014DFE30180 (Xue-dong Zhou)NIH R01 DE17974 (Hockin HK Xu)a Seed Grant (Hockin HK Xu) from the University of Maryland School of Dentistry
文摘Dental restorative materials with antimicrobial properties can inhibit bacterial colonization, which may result in a reduction of caries at tooth-filling interaction zones. This study aimed to develop antibacterial glass-ionomer cements (GIC) containing a quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM), and to investigate their effect on material performance and antibacterial properties. Different mass fractions (0, 1.1% and 2.2%) of DMADDM were incorporated into the GIC. The flexure strength, surface charge density, surface roughness and fluoride release were tested. A Streptococcus mutans biofilm model was used. Exopolysaccharides (EPS) staining was used to analyze the inhibitory effect of DMADDM on the biofilm matrix. In addition, biofilm metabolic activity, lactic acid metabolism and the expression of glucosyltransferase genes g/fB, gtfC and gtfD were measured. GIC containing 1.1% and 2.2% DMADDM had flexural strengths matching those of the commercial control (P〉0.1). DMADDM was able to increase the surface charge density but reduced surface roughness (P〈0.05). The incorporation of 1.1% and 2.2% DMADDM elevated the release of fluoride by the GIC in the first 2 days (P〈0.05). The novel DMADDM-modified GIC significantly reduced biofilm metabolic activity (P〈 0.05) and decreased lactic acid production (P〈 0.05). The quantitative polymerase chain reaction (qPCR) results showed that the expression of gtfB, g/fC and gtfD decreased when mass fractions of DMADDM increased (P〈0.05). EPS staining showed that both the bacteria and EPS in biofilm decreased in the DMADDM groups. The incorporation of DMADDM could modify the properties of GIC to influence the development of S. mutans biofilms. In this study, we investigated the interface properties of antibacterial materials for the first time. GIC containing DMADDM can improve material performance and antibacterial properties and may contribute to the better management of secondary caries.
文摘Melanoma is the most aggressive form of skin cancer.Disrupted intracellular signaling pathways are responsible for melanoma's extraordinary resistance to current chemotherapeutic modalities. The pathophysiologic basis for resistance to both chemo- and radiation therapy is rooted in altered genetic and epigenetic mechanisms that, in turn, result in the impairing of cell death machinery and/or excessive activation of cell growth and survival-dependent pathways. Although most current melanoma therapies target mitochondrial dysregulation,there is increasing evidence that endoplasmic reticulum(ER) stress-associated pathways play a role in the potentiation,initiation and maintenance of cell death machinery and autophagy. This review focuses on the reliability of ER-associated pathways as therapeutic targets for melanoma treatment.
文摘In addition to its contributing role in the development of chronic liver diseases, chronic hepatitis C virus(HCV) infection is associated with extrahepatic manifestations, particularly, cutaneous-based disorders including those with pruritus as a symptom. Pruritus is frequently associated with the development of chronic liver diseases such as cholestasis and chronic viral infection, and the accumulation of bile acids in patients' sera and tissues as a consequence of liver damage is considered the main cause of pruritus. In addition to their role in dietary lipid absorption, bile acids can trigger the activation of specific receptors, such as the G protein-coupled bile acid receptor(GPBA/ TGR5). These types of receptors are known to play a crucial role in the modulation of the systemic actions of bile acids. TGR5 expression in primary sensory neurons triggers the activation of the transient receptor potential vanilloid 1(TRPV1) leading to the induction of pruritus by an unknown mechanism. Although the pathologic phenomenon of pruritus is common, there is no uniformly effective therapy available. Understanding the mechanisms regulating the occurrence of pruritus together with the conduction of large-scale clinical and evidence-based studies, may help to create a standard treatment protocol. This review focuses on the etiopathogenesis and treatment strategies of pruritus associated with chronic HCV infection.
文摘High-quality DNA extraction is a crucial step in metagenomic studies.Bias by different isolation kits impairs the comparison across datasets.A trending topic is,however,the analysis of multiple metagenomes from the same patients to draw a holistic picture of microbiota associated with diseases.We thus collected bile,stool,saliva,plaque,sputum,and conjunctival swab samples and performed DNA extraction with three commercial kits.For each combination of the specimen type and DNA extraction kit,20-gigabase(Gb)metagenomic data were generated using short-read sequencing.While profiles of the specimen types showed close proximity to each other,we observed notable differences in the alpha diversity and composition of the microbiota depending on the DNA extraction kits.No kit outperformed all selected kits on every specimen.We reached consistently good results using the Qiagen QiAamp DNA Microbiome Kit.Depending on the specimen,our data indicate that over 10 Gb of sequencing data are required to achieve sufficient resolution,but DNA-based identification is superior to identification by mass spectrometry.Finally,longread nanopore sequencing confirmed the results(correlation coefficient>0.98).Our results thus suggest using a strategy with only one kit for studies aiming for a direct comparison of multiple microbiotas from the same patients.
文摘The micro- and nanostructures of human dental enamel were investigated by transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). For this purpose, TEM slices were prepared from teeth by focused ion-beam milling. These slices enabled TEM and transmission-EBSD (t-EBSD) investigations to be performed, while standard EBSD on bulk tooth samples resulted only in Kikuchi patterns. On the TEM slices, t-EBSD enabled automated mapping. The TEM images and the EBSD data dearly elucidated the arrangement of the hydroxyapatite crystals on the nanometer scale. Information regarding the crystallographic orientation of the apatite grains enabled the deduction of novel nanotechnological building principles of the enamel structure based on a chain-like arrangement of the crystallites.