0.05); while 100 ?mol?L-1 and 1 000 ?mol? L-1 bupivacaine reduced IK by 24%) ?4% and 33% ?6% (P

OBJECTIVEThe aim of this study is to analyze the three-dimensional crystal structure of SMU.2055 protein, a putative acetyltransferase from the major caries pathogen Streptococcus mutans (S. mutans). The design and selection of the structure-based small molecule inhibitors are also studied.

METHODSThe three-dimensional crystal structure of SMU.2055 protein was obtained by structural genomics research methods of gene cloning and expression, protein purification with Ni²⁺-chelating affinity chromatography, crystal screening, and X-ray diffraction data collection. An inhibitor virtual model matching with its target protein structure was set up using computer-aided drug design methods, virtual screening and fine docking, and Libdock and Autodock procedures.

RESULTSThe crystal of SMU.2055 protein was obtained, and its three-dimensional crystal structure was analyzed. This crystal was diffracted to a resolution of 0.23 nm. It belongs to orthorhombic space group C222(1), with unit cell parameters of a = 9.20 nm, b = 9.46 nm, and c = 19.39 nm. The asymmetric unit contained four molecules, with a solvent content of 56.7%. Moreover, five small molecule compounds, whose structure matched with that of the target protein in high degree, were designed and selected.

CONCLUSIONProtein crystallography research of S. mutans SMU.2055 helps to understand the structures and functions of proteins from S. mutans at the atomic level. These five compounds may be considered as effective inhibitors to SMU.2055. The virtual model of small molecule inhibitors we built will lay a foundation to the anticaries research based on the crystal structure of proteins.

Bacterial Proteins ; chemistry ; Cloning, Molecular ; Crystallization ; Crystallography, X-Ray ; Dental Caries ; Humans ; Streptococcus mutans ; chemistry ; X-Ray Diffraction

Objective To explore the relationship between emotional intelligence and job performance by investigating the level of them in pediatric nurses,and to provide a basis for improving job performance and the implementation of“quality care.Methods 335 pediatric nurses were investigated by using emotional intelligence scale and job performance scale.And the result of the investigation was analyzed statistically.Results The average score of the emotional intelligence of the pediatric nurses were (3.63±0.52),the highest score was interpersonal latitude (3.87± 0.69),the lowest score was management of emotions latitude (3.25±0.90); titles,the form of post and degree of nurses had a certain influence on the emotional intelligence.The score of job performance was(3.65±0.75).By Pearson correlation analysis,the emotional intelligence score and job performance score were obtained a significant positive correlation,self-motivation latitude and job performance were the most related,the management of emotional latitude job performance was the lowest.Conclusions Nursing managers should take corresponding measures to improve nurses' emotional intelligence and job performance levels,and promote the implementation of quality care effectively.

Objective To investigate the level and influencing factors of community nurses' quality of work life,and supply reference for improvement of community nursing management quality.Methods Totally 193 community nurses from 11 community health service center in Changchun were investigated with Chinese Version of Quality of Nurse Work Life Scale (QNWL).Results The total score of QWL was (165.00±22.19).The scores of work family balance,workload,work environment,social environment were (25.18±5.65),(39.30±5.07),(82.79±11.88) and (17.73±3.56).Multiple linear regression analysis showed that work like degree were influencing factors of community nurse' quality of work life,professional titles followed.Conclusions Community nurses' quality of work life need to be further improved.Nursing educators and managers should take measures to improve community nurse' quality of work life aimed at the influencing factors.

OBJECTIVEThis study aims to evaluate the effect of ptxA and ptxB genes, which are important genes in the L-ascorbate phosphotransferase system (PTS) of Streptococcus mutans (S. mutans).

METHODSThe ptxA-, ptxB-, and ptxAB-double deficient mutant as well as ptxAB-complemented strain were constructed. Quantitative real-time polymerase chain reaction analysis was performed to evaluate the expression of the target genes of wild-type S. mutans when L-ascorbate was used as the sole carbohydrate source. The OD₆₀₀ values of the wild type, deficient, and complemented strains were continuously monitored, and their growth curves were constructed to compare growth capacity.

RESULTSPolymerase chain reaction and sequencing analyses suggested that deficient and complemented strains were successfully constructed. The expression levelsof ptxA and ptxB significantly increased (P < 0.01) when L-ascorbate was used as the sole carbohydrate source. The growth capacity of the deficient mutants decreased compared with that of the wild-type strain. However, the wild-type phenotype could be restored in the complemented strain.

CONCLUSIONptxA and ptxB genes are associated with L-ascorbate metabolism of S. mutans. The construction of deficient strains and complemented strain lay a foundation for further mechanism study on L-ascorbate metabolism in S. mutans.

Bacterial Proteins ; genetics ; Genes, Bacterial ; Phosphotransferases ; metabolism ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans ; physiology ; Transcription Factors ; genetics

Objective To explore the main anatomical factors for relapse in patients underwent radical mas-toidectomy and discuss the preventive measures .Methods A retrospective study was carried out 36 patients who had underwent radical mastoidectomy and 100 patients (100 ears) who had been cured underwent radical mastoidectomy during July 2011 toSeptember 2013 .The patients underwent axial and coronal temporal Computed Tomography (CT) .The incidence of low -lying middle cranial fossa ,high jugular bulb ,anterior locati(36 ears)on of sigmoid si-nus ,dehiscent tympani tegmen ,dehiscent of the facial nerve canal ,large sinus tympani ,low -lying horizontal facial nerve were recorded .Results The incidence of low -lying middle cranial fossa(36 .1% ) ,anterior location of sig-moid sinus(41 .7% ) ,dehiscent tegmen tympani (30 .6% ) ,dehiscent of the facial nerve canal (41 .7% ) ,large sinus tympani(25 .0% ) ,low -lying horizontal facial nerve(22 .2% ) were higher than those of in the normal group .There was no significant difference in high jugular bulb .Conclusion The main anatomical factors for relapse in patients un-derwent radical mastoidectomy were low -lying middle cranial fossa ,anterior location of sigmoid sinus ,dehiscent tegmen tympani ,dehiscent of the facial nerve canal ,large sinus tympani ,low -lying horizontal facial nerve .

Objective To investigate the clinical significance of platelet activation markers CD62p and PAC-1 in patients with hypertension and coronary heart diease.Methods To select patients who were in the Second Affiliated Hospital of Dalian Medical University between January 2012 and September 2012,42 patients with hypertension,46 patients with coronary heart disease.Flow cytometry was used to test the positive percentage of the platelet surface activation markers CD62p and PAC-1 .To observe the difference among hypertension group,coronary heart disease group and health control group;hyper-tension and coronary heart disease group.Results The positive percentage of platelet activation markers CD62p and PAC-1 in hypertension (36.36±9.62,7.18±8.20)%,coronary heart disease group (42.74±14.60,8.81±12.53)% showed sta-tistically significant differences (t=4.150~5.853,P<0.01)compared with healthy control group (26.82±9.13 ,1.09± 1.05)%.The positive percentage of CD62p in coronary heart disease group (42.74±14.60)% was also higher than that of hypertension (36.36±9.62)%,and the difference between them was of statistical significance (t=2.444,P<0.05).Con-clusion The hypertensive patients and coronary heart disease were in pre-thrombotic state,the activation of platelet increase significantly.Molecular markers should be measured in hypertensive patients and coronary heart disease for prevention and treatment of thrombotic disease complication.

Objective To study the status of the self-medication behavior in children,and analyze the problems existing in medication of children by their parents,in order to provide references for the nurses to give medication guide to the parents of the children.Methods On the principle of convenience sampiing,120 hospitalized children's parents from a grade-Ⅲ A level hospitals in Jilin Province were investigated with a self-designed questionnaire.Results 79.3％ of the parents did not behaved standardly in children's self-medication,75.0％ of the parents' behaviors were not standardized in the management of the children's drugs; there was significant difference in the level of the children's self-medication among the parents with varied academic background or the age and the children's age.Conclusions The processes of self-medication in children have potential health risks,the nurses should strengthen health education,raise the parents' cognition of the risk of self-medication for children,and thus to help parents establish scientific and rational self-medication behaviors.

Objective To investigate the protective effect of theaflavins on thymus injury caused by total body irradiation (TBI).Methods Twenty-five C57BL/6 mice were randomly divided into 5 groups:control group,4 Gy TBI group,4 Gy TBI + 25 mg/kg theaflavins group,4 Gy TBI + 50 mg/kg theaflavins group and 4 Gy TBI + 100 mg/kg theaflavins group.Thymus index and total number of thymocytes were detected at the 14th d post-irradiation to determine the optimal dose of theaflavins.According to this optimal dose,32 C57BL/6 mice were randomly divided into 4 groups:control group,theaflavins group,4 Gy TBI group and 4 Gy TBI + theaflavins group.Thymus histomorphology,CD4CD8 T cell subsets,and reactive oxygen species (ROS) in thymocytes were examined at the 14th d post-irradiation.Results The irradiated thymus exhibited decreased thymus index and total number of thymocytes (P ＜ 0.05),aberrant histomorphology and T cell subsets (P ＜ 0.05),and increased ROS level in thymocytes (P ＜ 0.05).Compared with 4 Gy TBI group,the thymus index and total number of thymocytes were significantly increased in 4 Gy TBI + 50 mg/kg theaflavins group (P ＜ 0.05).The total number of thymocytes was significantly higher in 4 Gy TBI + 50 mg/kg theaflavins group than that in 4 Gy TBI + 25 mg/kg theaflavins group (P ＜ 0.05).Therefore,50 mg/kg theaflavins was chosen as the optimal dose for subsequent experiments.Moreover,the aberrant histomorphology of irradiated thymus was alleviated by theaflavins.A decline in the percentage of CD4-CD8-T cells and an elevation of CD4+CD8-and CD4+CD8+ T cells were found in irradiated mice administered with theaflavins (P ＜ 0.05).Compared with 4 Gy TBI group,the ROS level was significantly decreased in 4 Gy TBI + theaflavins group (P ＜ 0.05).Conclusion Theaflavins exhibits a protective effect on radiation-induced thymus injury.

Objective To explore the mechanism by which tumor necrosis factor alpha(TNF-α) induces RIP1 kinase-dependented apoptosis in L929-A fibroblastoma cells.Methods The sub-mitochondrial localization of receptor-interacting protein 1(RIP1),caspase-8 and Bid proteins was detected by dose-gradient trypsin digestion and Western blotting.The levels of reactive oxygen species (ROS),intracellular calcium concentration,mitochondrial membrane potential (MMP),and cellular adenosine triphosphate(ATP) content were determined by fluorescent probe labeling and flow cytometry assay.The mitochondrial respiratory chain complex Ⅰ and Ⅲ activities were detected by commercial kits.Nec-1,A RIP1 kinase specific inhibitor,and RIP1-/-or Bid-/-L929-A cells were used to detect the roles of RIP1 kinase and Bid protein in cell death.Results RIP1,caspase-8 and Bid proteins were co-located in the outer membrane of mitochondrial.TNF-α exposure for 3 h could induce Bid cleavage,inhibit mitochondrial respiratory chain complex Ⅲ activity and reduce MMP.Following these changes and after TNF-α exposure for 6-12 h,the intracellular calcium concentration and ROS were increased,whereas the ATP concentration was decreased,and the cells were killed.Inhibiting RIP1 kinase or knockdown RIP1 or Bid protein could suppress all the cytotoxic effects of TNF-α.Conclusion TNF-α treatment can result in RIP1 kinase-mediated Bid cleavage and inhibit mitochondrial respiratory chains and cell energy metabolism,which ultimately leads to the death of L929-A cells.