The effect of saliva contamination on the shear bond strength of orthodontic brackets, at various stages of the bonding procedure using a new self-etch primer was studied. The samples were divided into 4 groups according to 4 different enamel surface conditions: Group A: dry; Group B: saliva contamination before priming; Group C: saliva contamination after priming, and Group D: saliva contamination before and after priming. Stainless steel brackets were bonded in each test group with a light-cured composite resin (TransbondXT 3M). The shear bond strength was determined in the first 30 min after bonding. The analysis of variance indicated that the shear bond strengths of the 4 groups were significantly different (F = 11.89, P < 0.05). Tukey HSD tests indicated that contamination both before and after the application of the acid-etch primer resulted in a significantly lower (=4.6 +/- 1.7 MPa) shear bond strength than either the control group (=8. 8 +/- 1.9 MPa) or the groups where contamination occurred either before ( = 7.9 +/- 2.0 MPa) or after (= 6. 9 +/- 1.5 MPa) the application of the primer. It was concluded that the new acid-etch primer could maintain adequate shear bond strength if contamination occurred either before or after the application of the primer. On the other hand, contamination both before and after the application of the primer could significantly reduce the shear bond strength of orthodontic brackets.
Acid Etching, Dental ; Orthodontic Brackets ; Saliva ; Shear Strength

Objective To evaluate the blood-saving effect of different doses of tranexamic acid in patients undergoing cardiac valve replacement with cardiopulmonary bypass (CPB).Methods Ninety ASA physical status l-Ⅲ patients,aged 18-60 yr,with body mass index of 16-25 kg/m2,scheduled for elective cardiac valve replacement with CPB,were equally and randomly divided into 3 groups using a random number table:control group (group C),large-dose tranexamic acid group (group TL) and small-dose tranexamic acid group (group TS).Anesthesia was induced with iv injection of midazolam,sufentanil and pipecuronium.The patients were endotracheally intubated and mechanically ventilated.Anesthesia was maintained with inhalation of isoflurane and iv injection of midazolam,sufentanil and pipecuronium.After induction of anesthesia,tranexamlc acid 20 mg/kg was intravenously infused over 30 min,followed by continuous infusion at 20 mg· kg-1 · h-1 until the end of operation in group TL,tranexamlc acid 10 mg/kg was intravenously infused over 30 min,followed by continuous infusion at 10 mg· kg-1 · h-1 until the end of operation in group TS,while the equal volume of normal saline was given instead in group C.Venous blood samples were taken before induction,at the end of operation and at 24 h after operation for determination of hemoglobin (Hb),hematocrit (Hct),and platelct count (Plt).The volume of chest tube drainage was collected and recorded at 6 and 24 h after operation.The requirement for transfusion of allogeneic red blood cells was also recorded.The development of death and complications during days of hospitalization was recorded.Results Compared with group C,the volume of chest tube drainage was significantly decreased,the requirement for transfusion of allogeneic red blood cells was reduced (P ＜ 0.05),while no significant changes were found in Hb,Hct and Plt at each time point in TL and TS groups (P ＞ 0.05).There was no significant difference in the parameters mentioned above between group TL and group TS (P ＞ 0.05).The development of death and complications during days of hospitalization was not observed in the three groups.Conclusion Small-dose tranexamlc acid is suitable for blood-saving effect in patients undergoing cardiac valve replacement with CPB,that is loading dose of 10 mg/kg and maintenance dose of 10 mg· kg-1· h-1.

ObjectiveTo compare the changes in renal blood flow in elderly and adult patients during laparoscopic cholecystectomy.MethodsSixty ASA Ⅰ or Ⅱ patients of both sexes,aged 18-75 yr,weighing 48-78 kg,undergoing elective laparoscopic cholecystectomy were enrolled in this study.The patients were divided into 2 groups according to the age ( n =30): group Ⅰ young and middle-age (18-60 yr) and group Ⅱ elderly (61-75 yr).Anesthesia was induced with midazolam,fentanyl,propofol and vecuromium and maintained with infusion of propofol and remifentanil,isoflurane inhalation and intermittent iv boluses of vecuromium.The patients were intubated and mechanically ventilated.PETCO2 was maintained at 30-40 mm Hg.The probe of transesophageal echocardiography (TEE) was inserted into esophagus after tracheal intubation.The internal diameter and time integral of left renal artery were measured by TEE before pneumoperitoneum (baseline) and at 1,5,10,15,20 and 30 min of pneumoperitoneum and 1,5 min after deflation.The blood flow of left renal artery (LRAF) was calculated.The maximal derease in LRAF during pneumoperitoneum was analyzed.ResultsThe internal diameter and time integral of left renal artery and LRAF were significantly decreased during peumoperitoneum and at 1 min after deflation in both groups ( P ＜ 0.05).LRAF before peumoperitoneum was significantly lower,and the time point of LRAF maximum decrease during pneumoperitoneum was later in group Ⅱ than in group Ⅰ ( P ＜ 0.05).ConclusionThe renal blood flow is temporary decreased during laparoscopic cholecystectomy both in young and middle age and elderly patients.The time point of LRAF maximum decrease in elderly patients is later than that in adult patients.

0.05); while in the androgen group, SR Ca 2+-ATPase activity [22.91 ? 4.56 ?mol Pi/(mg protein?hour)] was reduced to 67% (P

Objective To evaluate the effects of pulmonary static inflation with different pressures on postoperative lung function in patients undergoing cardiac valve replacement with cardiopulmonary bypass (CPB).Methods Sixty ASA Ⅱ or Ⅲ patients,aged 26-70 yr,weighing 47-78 kg,undergoing elective cardiac valve replacement with CPB,were randomly divided into 2 groups (n =30 each):pulmonary static inflation with 5 cm H2O group (group L) and with 10 cm H2O group (group H).In L and H groups,pulmonary static inflation was performed with the pressure maintained at 5 and 10 cm H2O,respectively,after stopping mechanical ventilation during CPB.Arterial blood samples were taken before skin incision and at 1,3 and 6 h after termination of CPB for blood gas analysis.The alveolar-arterial oxygen pressure difference (D(A-a)O2),respiratory index (RI) and oxy.genation index (OI) were calculated.The indwelling time of endotracheal tube after operation and duration of ICU stay were recorded.Results Compared with group L,D(A-a)O2 and RI were significantly decreased and OI was increased at 1,3 and 6 h after termination of CPB,the incidence of OI less than 300 mm Hg was decreased (P ＜ 0.05),and no significant change was found in the indwelling time of endotracheal tube after operation and duration of ICU stay in H group (P ＞ 0.05).Collusion Pulmonary static inflation with 10 cm H2O can better improve postoperative pulmonary diffusion function than with 5 cm H2O in patients undergoing cardiac valve replacement with CPB.

Objective To understand the status of depression and compare with the same age group of Chinese norms of CES-D in urban areas and analyze its potential influencing factors among male nursing undergraduates.Methods In this cross-sectional study,the CES-D and self-made questionnaire were administrated to 102 male nursing undergraduates from two schools of nursing through two-stage random sampling.Results The prevalence of depression was 14.0％,and the score of nursing undergraduates was (11.00±6.37) points,which had no significant difference from the scores of the same age group of Chinese norms in urban areas.Univariate analysis showed that coming from countryside,worse interpersonal relationship,worse career prospect,getting no attention from parents had some significant association with depression.Multivariate analysis showed that worse career prospect and getting no attention from parents associated with lower CES-D scores.Condusions For male nursing undergraduates,efforts should be given from the aspects of families and career prospects to improve their psychological health condition,and reserve qualified resources for nursing profession.

Objective To explore the effect of oxidative stress on human Wiskott-Aldrich syndrome related protein 2 (WAVE2) expression in placental trophoblasts in women with preeclampsia.Methods (1) Twenty women with preeclampsia and twenty-three normal term pregnant women,delivered from August 15,2011 to February 23,2012 in the First Affiliated Hospital of Chongqing Medical University,were recruited and divided into preeclampsia group and control group.Placenta samples were collected after cesarean section.The localization and distribution of WAVE2 in placenta was studied by immunohistochemistry.Quantitative real-time polymerase chain reaction and Western blot were employed to assay the WAVE2 mRNA and protein levels.Tissue homogenates was applied to determine the levels of reactive oxygen species (ROS).The correlation between ROS levels and WAVE2 was also analyzed.(2) An in vitro hypoxia/reoxygenation (H/R) model was utilized to simulate ischemia/reperfusion injury to placental trophoblasts.The HTR-8/ SVneo cells (immortalized human first trimester extravillous trophoblast cells) were pre-incubated overnight,after exposure to H/R or normoxic conditions for 48 hours.Flow cytometry was employed to analyze intracellular ROS level.Meanwhile,Transwell assay was utilized to analyze the invasion and migration of HTR-8/SVneo cells.The location and expression of WAVE2 in trophoblasts was evaluated by cell immunofluorescence and Western blot.Statistical differences between the two groups were evaluated by independent t-tests.Pearson's correlation coefficient test was used for correlation analysis.Results (1)Compared with the control group,preeclampsia group had significantly higher 24-hour proteinuria [(1.96±0.24) g vs (0.08±0.05) g,t=19.436,P＜0.05],systolic blood pressure [(154 ± 13) mm Hg vs (98 ±11) mm Hg,t=11.324,P＜0.05] and diastolic blood pressure [(105±14) mm Hgvs (69±8) mm Hg,t=9.612,P＜0.05].In addition,the placental weight and birth weight of infants in preeclampsia group were significantly reduced as compared to the control group [(432±53) g vs (536±67) g,(2446± 187) g vs (3207± 233) g,t=14.562 and 16.307,allP＜0.05)].The WAVE2 mRNA level (0.28±0.07 vs 1.01±0.02,t=12.747,P＜0.05) and the WAVE2 protein levels (0.63±0.08 vs 1.34±0.19,t=11.648,P＜0.05) were also significantly decreased in preeclampsia groups.The level of ROS in placenta in the preeclampsia group was significantly higher than in control group [(144.22 ± 12.32) nmol/(mg · prot) vs (75.17 ± 8.71) nmol/(mg · prot),t=20.467,P＜0.05].There was significant negative correlation between ROS level and WAVE2 protein expression in preeclamptic placenta (r =-0.726,P =0.000).(2) In vitro study showed that,the levels of ROS in normoxia group and H/R group was (82.9±5.8)％ and (155.6±8.1)％,(t=12.747,P＜0.05).Compared with normoxia condition,decreased cell invasion and migration were found in HTR-8/SVneo cells in H/R group [(51.9 ± 3.3)％ and (58.4 ±4.2)％ respectively,t=11.034 and 13.839,P＜0.05].Results from the cell immunofluorescence showed that WAVE2 protein located in the cytoplasm of HTR-8/SVneo cells,and the expression of WAVE2 protein was significant decreased in HTR-8/SVneo cells after exposure to H/R for 48 h (0.37±0.05 vs 0.76±0.06,t=8.631,P＜0.05).Conclusions Excessive oxidative stress in preeclamptic placentas was correlated with the decreased expression of WAVE2.H/R-induced oxidative stress could decrease WAVE2 expression,which may contribute to impaired trophoblast invasion and migration in preeclampsia.

Objective To evaluate the effects of small dose of dopamine on the renal blood flow in the elderly patients undergoing cardiac valve replacement under cardiopulmonary bypass (CPB).Methods Sixty elderly patients,of ASA physical status Ⅱ or Ⅲ,aged 65-74 yr,weighing 52-77 kg,scheduled for elective cardiac valve replacement under CPB,were randomized to receive either normal saline (group C,n =30) or dopamine (group D,n =30).After beginning of surgery,CPB was established routinely.In group D,dopamine was continuously infused for 20 min at a rate of 2 μg· kg-1 · min-1 starting from 10 min after the hearts were perfused with cardioplegic solution for the first time,while the equal volume of normal saline was given in group C.The left renal blood flow velocity was measured by transesophageal echocardiography and mean arterial pressure was recorded before and after dopamine infusion.Blood samples were obtained before surgery and at 24 h after surgery for determination of blood urea nitrogen concentrations.Results Blood urea nitrogen concentrations were significantly increased at 24 h after surgery than that before surgery in the two groups.There was no significant difference in mean arterial pressure and the left renal blood flow velocity before and after dopamine infusion between the two groups.Conclusion Small dose of dopamine (2 μg· kg-1· min-1) dose not increase the renal blood flow or improve the postoperative renal function in the elderly patients undergoing cardiac valve replacement under CPB.

Objective:To observe HSP70 expression during experimental tooth movement in rats.Methods:Orthodontic appliance was placed between the maxillary right first molar and maxillary central incisors of 30 adult SD rats.The rats were killed at 1,3,5,7,14 d after orthodontic force application,samples of experimental teeth with periodontal tissue were prepared for immunohistochemical examination of HSP70 expression.Result:Strong expression of HSP 70 in periodontal ligment was observed at 1 and 3 d after orthodontic force application,positive at 5 d and weak positive at 7 and 14 d.Conclusion:HSP 70 is expressed in periodontal ligment at different levels in different stages during orthodontic tooth movement.

Objective:To investigate the effects of estrogen on sarcoplasmic reticulum (SR) Ca2+-ATPase activity and gene expression in female rats genioglossal muscle (GG), and explore the possible molecular biology mechanism.Methods:30 male rats were randomly divided into 3 groups:Control group, ovariectomy(OVX)group, ovariectomized animals receiving estradiol replacement (OVX+E2) group. The rats were sacrificed 6 weeks after surgery, and the genioglossus was taken out for analysis. Ca2+-ATPase activity was measured by detecting inorganic phosphorus ion, and SR Ca2+-ATPase (SERCA) mRNA level was observed using fluorescence quantitative reverse transcription-polymerase chain reaction (FQ RT-PCR) method. Results:Compared to the control group, SR Ca2+-ATPase activity of OVX group remarkably reduced(P0.05).Conclusion:Serum level of estrogen of adult female rats may influence the function of genioglossal muscle by influencing SR Ca2+-ATPase activity and the SERCA mRNA expression.