Changes in expressions of sRNA SpR19 and its potential target GroEL in Streptococcus mutans strains with different cariogenicity cultured under different pH conditions / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the changes in the expression level of sRNA SpR19 and its potential target protein GroEL in clinical isolates of Streptococcus mutans with different cariogenicity exposed to different pH conditions and explore the possibility of using these molecules as biomarkers for assessing the cariogenicity of the bacteria.</p><p><b>METHODS</b>The total RNAs were extracted from the clinical isolates of Streptococcus mutans with high (strain 17) and low cariogenicity (strain 5) for high-throughput sequencing for profiling of the differentially expressed sRNAs. The candidate sRNA, SpR19, was selected for further study on the basis of bioinformatics analysis considering the role of its potential target in the cariogenic process. The differential expression levels of SpR19 in the strains exposed to both pH5.5 and pH7 culture conditions were verified by quantitative real-time PCR. The expression of the potential target of SpR19, GroEL, was also investigated at both the protein and mRNA level using Western blotting and quantitative real-time PCR.</p><p><b>RESULTS</b>Bioinformatic analysis suggested multiple potential target sites of SpR19 both in GroEL mRNA and in the upstream and downstream inter-genic regions. Under different pH conditions, the highly cariogenic strain 17 expressed consistently low levels of SpR19 as compared with the strain 5 with a low cariogenicity; GroEL showed a reverse expression pattern in the 2 strains. An inverse correlation was found between the expressions of SpR19 and GroEL.</p><p><b>CONCLUSION</b>The highly cariogenic strain 17 expressed low levels of SpR19 and high levels of GroEL in both acidic and neutral culture conditions. SpR19 may negatively regulate the cariogenicity of Streptococcus mutants by targeting at GroEL.</p>

Downregulation of Notch-regulated Ankyrin Repeat Protein Exerts Antitumor Activities against Growth of Thyroid Cancer / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The Notch-regulated ankyrin repeat protein (NRARP) is recently found to promote proliferation of breast cancer cells. The role of NRARP in carcinogenesis deserves extensive investigations. This study attempted to investigate the expression of NRARP in thyroid cancer tissues and assess the influence of NRARP on cell proliferation, apoptosis, cell cycle, and invasion in thyroid cancer.</p><p><b>METHODS</b>Thirty-four cases with thyroid cancer were collected from the Department of General Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine between 2011 and 2012. Immunohistochemistry was used to detect the level of NRARP in cancer tissues. Lentivirus carrying NRARP-shRNA (Lenti-NRARP-shRNA) was applied to down-regulate NRARP expression. Cell viability was tested after treatment with Lenti-NRARP-shRNA using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptosis and cell cycle distribution were determined by flow cytometry. Cell invasion was tested using Transwell invasion assay. In addition, expressions of several cell cycle-associated and apoptosis-associated proteins were examined using Western blotting after transfection. Student's t-test, one-way analysis of variance (ANOVA), or Kaplan-Meier were used to analyze the differences between two group or three groups.</p><p><b>RESULTS</b>NRARP was highly expressed in thyroid cancer tissues. Lenti-NRARP-shRNA showed significantly inhibitory activities against cell growth at a multiplicity of infection of 10 or higher (P < 0.05). Lenti-NRARP-shRNA-induced G1 arrest (BHT101: 72.57% ± 5.32%; 8305C: 75.45% ± 5.26%) by promoting p21 expression, induced apoptosis by promoting bax expression and suppressing bcl-2 expression, and inhibited cell invasion by suppressing matrix metalloproteinase-9 expression.</p><p><b>CONCLUSION</b>Downregulation of NRARP expression exerts significant antitumor activities against cell growth and invasion of thyroid cancer, that suggests a potential role of NRARP in thyroid cancer targeted therapy.</p>

Aging performances for resisting low-temperature of three dental Yttria-stabilized zirconia ceramic core materials / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The low-temperature resistance aging performance of Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) is the key effective factor that influences the long-term success rate of prosthesis. The objective of this study was to test and compare the aging performances for resisting low temperature of Lava Frame, Cercon Smart, and Upcera Yttria-stabilized zirconia core materials, via analyzing the micro and the crystal phases of the materials, and measure the three-point bending strength and the fracture toughness.</p><p><b>METHODS</b>The three zirconia green bodies were prepared as 60 test samples for three-point bending strength and as 60 test samples for fracture toughness. The test samples for three-point bending strength and fracture toughness were assigned to five groups and were treated respectively for 0, 5, 10, 15, and 20 hours to observe the micro and the crystal phases of the test samples. Then the three-point bending strength and fracture toughness were tested by X-ray diffraction (XRD).</p><p><b>RESULTS</b>The m phase content of Lava Frame was raised from 7.70% to 13.01%; the m phase content of Cercon Smart was raised from 4.95% to 8.53%; and Lava Frame is raised from 10.84% to 35.18%. The three-point bending strengths of the three zirconia core materials were higher than 1100 MPa and the fracture toughness was higher than 3 MPa·m(1/2). The three-point bending strength and the fracture toughness of Upcra zirconia decreased the most, followed by Lava Frame, and then by Cercon Smart.</p><p><b>CONCLUSION</b>The aging resistance sequences of the three zirconia core materials are, from strong to weak, Cercon Smart, Lava Frame, and Upcera.</p>

Minimal intervention dentistry: a vision of caries management for older patients. II / 华西口腔医学杂志

Minimal intervention dentistry (MID) is a new approach to caries management in older patients, which emphasize on early discussion, early diagnosis and early treatment. It focuses on stopping the disease process and patient-friendly surgical intervention only when required. Geriatric MID can improve oral ecological balance, lower caries risk, reverse dental caries process and reduce the pain when surgical intervention required. It can help clinicians in coping with erosion, abrasion, demineralization, rampant dental caries, retained roots, recurrent caries, subgingival caries, "wet" oral environment, salivary dysfunction, high plaque levels, swollen or bleeding gum and poor compliance in older patients. This article mainly describes the application of MID in surgical intervention of dental caries, including the strategies for caries removal, cavity preparation, choice of biology material, management of erosion and abrasion, "wet" subgingival environment and vital pulp therapy.

Three-dimensional accuracy of plaster casts obtained using three impression materials / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the accuracy of 3 impression materials in reproductions of simian dental arches using a 3-dimensional optical digitizer.</p><p><b>METHODS</b>Two simian dental arches were prepared as the master models. Impressions were made for stone casts using three impression materials, including alginate impression materials, C-silicone materials and Impregum-Penta polyether rubber. Five plaster replication models for each master model, as well as for each impression materials were made. The master models and the casts were digitized using a 3-dimensional optical scanner and digitizer. The images of each plaster cast and its original master model were superimposed to obtain the setting cross-section volume of the dental crown. The ratios of the plaster cast volume change and discrepancy distribution patterns were analyzed.</p><p><b>RESULTS</b>Compared with the volume of the master models, the discrepancies of the plaster casts volume were -5.84%, -3.21%, and -0.63% for alginate impression materials, silicone materials and Impregum-Penta polyether rubber, respectively. The discrepancy between the master models and casts from alginate material was statistically significant (P<0.05), but not for silicone materials or Impregum-Penta polyether rubber. Maximal deviation of image fitting was located in the cervix and the gingival areas.</p><p><b>CONCLUSION</b>The volumes of all the plaster casts from the 3 impression material are smaller than that of the master model. Impregum-Penta polyether rubber allows the most precise and silicone material the relatively accurate reproduction of the denture model, while alginate can not. The major error areas are in the dental cervix and gingival region.</p>

Minimal intervention dentistry: a vision of caries management for older patients. I / 华西口腔医学杂志

The ageing of Chinese population combined with development of geriatric dentistry results in increased retention of natural teeth and higher risk of dental caries in older patients. This means new challenge for clinicians. Minimal intervention dentistry (MID) is a new approach to caries management in older patients, which emphasize on early discussion, early diagnosis and early treatment. It focuses on stopping the disease process and patient-friendly surgical intervention only when required. This article describes the application of MID in geriatric caries management: Assessment of the risk of caries; early detection (before cavity appears); external and internal remineralization.

Inhibition effect of methylene blue on the acids production of Streptococcus mutans / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the effect of methylene blue on the growth and acid production of Streptococcus mutans, and the effect of methylene blue on acid production metabolism in plaque glycolysis model (i-PGM) in vitro, and investigate the practicability of methylene blue as a new kind of dental caries prevention agent.</p><p><b>METHODS</b>Nephelometer method was used to measure OD value of Streptococcus mutans culture fluid in the different incubation conditions. The kinds and quantities of acid produced by Streptococcus mutans in the different incubation conditions were measured with gas chromatography. pH values of glycolysis buffer media of i-PGM in the different treatment conditions were measured by ORION electrode.</p><p><b>RESULTS</b>(1) The OD value of Streptococcus mutans treated by methylene blue was lower than that by normal saline, and there was significant statistical difference between them. (2) The kinds of acid in three different culture fluid were same, but the total quantities of acid were significantly different among three different culture fluid, in which the total quantities of acid of culture fluids treated by glucose was the greatest, and treated by methylene blue was the lest. (3) The pH value of i-PGM treated by methylene blue was significantly different compared with negative control group, but was not significantly different compared with positive control group.</p><p><b>CONCLUSION</b>Methylene blue can inhibit the growth and acid production metabolism of Streptococcus matans and acid production metabolism of i-PGM.</p>