10.3969/j.issn.1007-3969.2013.05.003

Objective To preliminarily select safe parameters for different forms of teeth by irradiating 532 nm picosecond Nd∶YAG laser on human isolated teeth with different irradiation time length and power.Methods Isolated human teeth including anterior teeth,premolars,molars were irradiated with 532 nm picosecond laser.Repeated measurements were made for each tooth by thermometer to measure the temperature of pulp chamber on different time point and power,and the temperature change (△T) was calculated.Results △T of the anterior irradiation group at 0.6 W,30 s;0.8 W,20 s and 30 s;1.0 W,10 s,20s and 30s were more than 5.6 ℃,which was the same with that of premolar group at 1.0 W,30s.△T of the molar group at 1.0 W,30 s was less than 5.6 ℃.Under certain power,the temperature of pulp chamber increased with the prolonging of irradiation time (P＜0.05).At a certain time,temperature increased with the power (P＜0.05).Conclusions It is safe to carry out operation on the parameters setting of 0.8 W,10 s and 0.6 W,20 s irradiation for anteriors teeth;0.4 W,30 s,0.8W,30 s and 1.0 W,20 s for premolar teeth,and 1 W,30 s for molar teeth.In the application of 532 nm picosecond laser,attention is required to be paid on parameter setting to control input power and irradiation time.

Objective To study the application of photodynamic therapy (PDT) for dental caries prevention using whole body luminescence fiber,and to investigate the effects of PDT on the content of Ca and P in rat molar enamel.Method The rat dental caries model was established by inoculating with S.mutans.Eighty male rats were randomly divided into five groups,including three experimental groups:17 mW (8 mW/cm2) PDT (group A),34 mW (15 mW/cm2) PDT (group B),68 mW (30 mW/cm2) PDT (group C),a positive control group:20 g/L NaF solution (group D),and a negative control group:0.9％ physiological saline (group E).The experimental groups were treated by 40 μg/mL hematoporphyrin monomethyl ether (HMME) and 650 nm diode laser irradiation.The experiments were conducted for 4 weeks.The contents of Ca and P in the molars of each group were measured by inductively coupled plasma emission spectrometry.Results The contents of Ca and P in group B,C and D after PDT were significantly higher than those in group A and E (all P＜0.05).The contents of Ca and P in group A showed no significant difference before and after PDT,while those in groups B and C showed significant increase after PDT (all P＜O.05).The increment of Ca in group A after PDT was lower than that in group D (P＜0.05),while those in group B and C were significantly higher than those in group D (all P＜0.05).There was no significant difference in the increment of Ca and P between group B and C after PDT.Conclusions In the range of the experimental parameters,the PDT promoted effect of tooth remineralization is better than 20 g/L NaF.The levels of Ca and P in the tooth enamel can be promoted by PDT treatment,and the contents of Ca and P are related to the pewer of PDT.The effect of low power PDT on the remineralization of enamel is not obvious.The contents of Ca and P in the tooth enamel are increased with laser power of PDT.When the laser power increased to a certain value,the change in contents of the two elements is not obvious.PDT can maintain the tooth remineralization microenvironment.

Objective: To investigate the prevalence of intention to smoke and current smoking and identify its influencing factors among middle school students in Ningbo City, so as to provide insights into the development and implementation of tobacco control among adolescents. Methods: The epidemiological data of tobacco use among adolescents in Ningbo City in 2021 were collected, including demographics, tobacco use, parents' and close friends' smoking status, secondhand smoke exposure and tobacco advertisement exposure. The intention to smoke, current smoking, secondhand smoke exposure and tobacco advertisement exposure were descriptively analyzed among middle school students, and the factors affecting intention to smoke, current smoking were identified using a multivariable logistic regression analysis. Results: Totally 1 591 questionnaires were allocated to middle school students, and 1 574 valid questionnaires were recovered, with an effective recovery rate of 98.93%. The respondents included 787 junior high school students, 535 high school students and 252 vocational high school students, and the prevalence was intention to smoke and current smoking was 6.73% and 1.78% among the respondents, respectively. Multivariable logistic regression analysis identified boys (OR=2.398, 95%CI: 1.466-3.922), high school students (OR=2.051, 95%CI: 1.212-3.470), vocational high school students (OR=2.011, 95%CI: 1.108-3.650), more than 100 yuan disposable pocket money per week (OR=2.534, 95%CI: 1.301-4.935) and close friends' smoking (OR=4.310, 95% CI: 2.755-6.757) as risk factors of intention to smoke, and boys (OR=12.420, 95%CI: 1.645-93.753), close friends' smoking (OR=11.628, 95%CI: 4.348-31.250) and parents' smoking (OR=2.667, 95%CI: 1.029-6.897) as risk factors of current smoking among middle school students. The prevalence of secondhand smoke exposure and tobacco advertisement exposure was 76.43% and 51.65%, and television/video/cinema was the most likely route of tobacco advertisement exposure (42.06%). Conclusions The prevalence of intention to smoke and current smoking is low among middle school students in Ningbo City; however, the proportions of exposure to secondhand smoke and tobacco advertisement are relatively high. Tobacco control interventions are recommended to be intensified targeting high-risk populations, such as vocational high school students.

Objective: To investigate the e-cigarette use and its influencing factors among middle school students in Ningbo City, Zhejiang Province, so as to provide insights into e-cigarette control among adolescents. Methods: Students of junior high schools, high schools and vocational high schools in Ningbo City were sampled using a multi-stage stratified cluster random sampling method from September to October 2021. Students' general information, cigarette and e-cigarette use and e-cigarette advertising exposure were collected using 2021 China Youth Tobacco Survey Questionnaire, and proportions of e-cigarette current use and attempt to use were analyzed. Factors affecting the attempt to use e-cigarettes were identified using a multivariable logistic regression model. Results: Totally 1 591 questionnaires were allocated, and 1 574 valid questionnaires were recovered, with an effective rate of 98.93%. The respondents included 863 males (54.83%) and 711 females (45.17%); 787 junior high school students (50.00%), 535 high school students (33.99%) and 252 vocational high school students (16.01%). The proportion of current e-cigarette use was 1.91% and the proportion of attempt to use e-cigarettes was 6.61%. Multivariable logistic regression analysis identified males (OR=2.544, 95%CI: 1.438-4.501), living in rural areas (OR=2.084, 95%CI: 1.195-3.634), having close friends who were smokers (OR=4.828, 95%CI: 2.936-7.940), witnessing teachers smoking at school (OR=2.766, 95%CI: 1.642-4.659), e-cigarette advertising exposure (OR=2.155, 95%CI: 1.315-3.532), current cigarette use (OR=9.365, 95%CI: 2.610-33.603) and attempt to use cigarettes (OR=7.519, 95%CI: 4.115-13.737) as promoting factors for the attempt to use e-cigarette. Conclusions There are e-cigarette use behaviors among middle school students in Ningbo City. Having teachers or close friends who were smokers, cigarette use behaviors and e-cigarette advertising exposure may increase the risk of attempt to use e-cigarettes among middle school students.

Objective To study the adjuvant immunoactivity of polysaccharides from Panax japonicus by alcohol of different concentrations;To discuss its part with the strongest adjuvant immunoactivity. Methods Polysaccharides from Panax japonicus was sunk with alcohol of different concentrations, and 30%alcohol compound, 60%and 90%alcohol polysaccharide were obtained. Different segments of polysaccharide and OVA protein were injected to mice once a week for three times for immunity. Five days after the last immunity, the mice were executed to collect blood, and the antibody titer was determined. The three parts of alcohol compound were scanned by infrared spectrum to determine the type of polysaccharide preliminarily. Results Compared with the control group, the antibody titer of different segments of polysaccharide obviously increased, especially the polysaccharide sunk by 60%alcohol. Infrared spectrum analysis showed that polysaccharides from Panax japonicus contained pyranose ring structure. Conclusion Polysaccharides from Panax japonicus has significant adjuvant immunoactivity, and polysaccharide sunk by 60%alcohol has the strongest adjuvant effects.

BACKGROUND:Angiotensin II receptor antagonists have been found to exerct a stronger protective effect on bone than angiotensin converting enzyme inhibitors. OBJECTIVE:To investigate the effect of different concentrations of irbesartan (angiotensin II receptor antagonist) on the differentiation and mineralization of mouse preosteoblasts. METHODS:Mouse preosteoblast cel lines MC3T3-E1 in logarithmic phase were selected and cultured in the osteogenic induction medium containing 0 (control group), 0.001, 0.01, 0.1 mmol/L irbesartan, respectively. Ten days later, the cel differentiation was observed by alkaline phosphatase staining. The mineralization was observed by alizarin red staining after 21 days of culture. mRNA expressions of osteocalcin, alkaline phosphatase and Runt-associated transcription factor 2 in osteoblasts were detected by real-time PCR at 1, 4, 7, 14 and 21 days of culture. RESULTS AND CONCLUSION:The activity of alkaline phosphatase in al the irbesartan groups (0, 0.001, 0.01, 0.1) was higher than that in the control group (P<0.05), which was the most obvious in 0.01 mmol/L. The number and area of calcium nodules in each irbesartan group were significantly higher than those in the control group (P<0.05), especial y in 0.01 mmol/L. Compared with the control group, 0.01 mmol/L irbesartan significantly upregulated the mRNA expressions of osteocalcin, alkaline phosphatase and Runt-associated transcription factor 2 (P<0.05). These results suggest that 0.01 mmol/L irbesartan significantly promotes the differentiation and mineralization of osteoblasts.

Objective To discuss the protection mechanism of total saponins from Panax japonicus on acute hepatic injury induced by carbon tetrachloride. Methods HepG2 cells were used to establish CCl4-induced liver cell injury model in vitro experiments. Mouse model of acute liver injury was caused by 1%CCl4 oil on Balb/c. Mice were randomly divided into normal group, model group and medicine group. Mice in the medicine group were given a gavage with 20 mL/kg total saponins from Panax japonicus, while mice in the other two groups were given a gavage with the same amount of stroke-physiological saline solution. MTT method was used to detect the activity of hepatic cells. The pathological changes of mouse liver were examined by HE staining. RT-PCR was used to detect changes in the expression of transforming growth TGF-β, TNF-α, and TLR4 mRNA. Results Compared with normal group, less hepatic cells survived in model group (P<0.01);compared with model group, more hepatic cells survived in medicine group (P<0.01). HE staining showed that damages in liver tissues of medicine group significantly improved than those in model group. RT-PCR results showed that the levels of TGF-β, TNF-α, and expression of TLR4 mRNA increased more significantly than those in model group;the expression of TGF-β, TNF-α, and TLR4 mRNA in medicine group decreased more significantly than those in model group, with statistical significance (P<0.01). Conclusion The total saponins from Panax japonicus has a protective effect on liver injury induced by carbon tetrachloride.

To investigate the effects of resveratrol (RV) in reprogramming mouse embryonic fibroblasts (MEFs) into induced pluripotent stem cells (iPSCs) and the related mechanism.

Objective To investigate the serum IL-33 level and its association with TH1,TH2,TH17 and Treg cells in patients with unexplained recurrent spontaneous abortion(URSA).Methods Forty-six URSA patients and 40 healthy controls were enrolled.The proportions of TH1,TH2,TH17 and Treg cells in peripheral blood samples were determined by flow cytometry,and serum IL-33 levels by ELISA.Results The levels of serum IL-33 in URSA patients were significantly lower than that in healthy controls.The proportions of TH2 and Treg cells in URSA patients were significantly lower than that in healthy controls (P ＜ 0.05),while the proportions of TH 1 and TH 17 cells in URSA patients were significantly higher than that in healthy controls.Serum IL-33 levels were negatively correlated with the proportions of TH 1 and TH17 cells,and positively with that of TH2 cells,while no correlation with Treg cells.Conclusion Serum IL-33 levels decrease significantly in URSA patients,and are correlated with the proportions of TH1,TH2 and TH17 cells,indicating that IL-33 may be associated with TH1,TH2 and TH17 cells in URSA patients.