Objective To investigate the effects of pulsed Nd∶YAG laser combined with NaF solution on acid resistance of human dental enamel and dentin in vitro Methods A total of 20 enamel samples and 20 dentin samples were treated with both laser plus NaF, laser only, NaF only, or no treatment(control) Then all samples were immersed in lactic acid demineralization solution(pH 4 5) for 48 h at 37 ℃ The concentration of Ca 2+ (?10 -6 g) dissolved in the solution was measured by atomic absorption spectrophotometry Results In both enamel and dentin samples, the lowest mean Ca 2+ concentration was recorded in laser plus NaF treated group (62 055?5 879,137 474?4 444)?10 -6 g The control samples showed the highest mean of Ca 2+ concentration (143 760?5 443 and 182 726?16 115)?10 -6 g The mean Ca 2+ concentration in laser plus NaF - or NaF - or laser treated group decreased significantly as compared with that in the control( P

Objective:To investigate the effect of initiator on pulsed Nd:YAG laser in the acid resistance of human teeth in vitro. Methods:A total of 25 enamel-samples and 25 dentine-samples were divided into laser plus initiator (a layer of Beijing black ink) group and laser only group.Each of the two groups was divided into five subgroups.The samples in the 5 subgroups were irritated by Na:YAG laser with an energy(J/cm2) of 0,20,30,40 and 50 respectively. Then all samples were immersed in 0.1 mol/L lactic acid demineralization solutions(pH 4.5) for 48 h at 37 ℃. The concentration of Ca 2+ (?10 -6 g) dissolved in the solution was measured by the calcium selective electrode. Results:Laser of 20-50 J/cm2 decreased the Ca 2+ concerntration in demineralization solution(P0.05).The initiator plus laser of 30-40 J/cm2 decreased the Ca 2+ release of dentine samples than laser only group (P

Objective To investigate the expressions of tissue factor pathway inhibitor-2 (TFPI-2 ) and matrix metalloproteinase-9 (MMP-9)in esophageal squamous cell carcinoma(ESCC)tissue and their relationship with vasculogenic mimicry (VM).Methods 162 cases of esophageal squamous cell carcinoma tissues were collected. CD34/periodic acid-schiff double staining was performed to observe the distribution of VM in ESCC tissue,and immunohistochemical staining was used to detect the expressions of TFPI-2 and MMP-9 in ESCC tissue. The relationship between VM and the clinicopathologic parameters of ESCC, the expressions of TFPI-2 and MMP-9 were analyzed.Results The positive rate of VM in ESCC tissue was 20.37%.The positive rate of VM in poorly differentiated group(40.38%)was significantly higher than those in moderately differentiated group(11.76%)and well differentiated group (7.14%)(χ2 = 20.915, P < 0.01 ). The positive rate of VM in TNM Ⅰ-Ⅱ(11.59%)group was significantly lower than that in TNM Ⅲ group(26.88%)(χ2=5.707,P=0.017).The positive rate of TFPI-2 in VM(+)group(33.34%)was significantly higher than that in VM(-)group(6.45%) (χ2=4.582,P=0.032)in poorly differentiated ESCC.The positive rate of MMP-9 in VM(+)group(78.79%) was significantly higher than that in VM(-)group(44.96%)(χ2=12.05,P=0.001).The expression level of TFPI-2 in poorly differentiated group was positively correlated with VM (r= 0.166,P= 0.032 ), and the expression level of MMP-9 was positively correlated with the VM(r=0.183,P=0.018).The five-year survival rate in VM (-) group was significant higher than that in VM (+) group (χ2 = 22.84, P < 0.001 ). Conclusion VM exists in ESCC tissue,especially in poorly differentiated and advanced ESCC tissue.VM is related to poor prognostis of ESCC.TFPI-2 and MMP-9 might involve in the formation of VM in ESCC.

Objective To investigate the effect of Toll-like receptor 2(TLR2)on the proliferation of human keratinocytes.Methods Keratinocytes were isolated from the foreskin of children,and subjected to primary culture.Atier 3-5 passages.the kemtinocytes were incubated with various concentrations of peptidoglycan(PGN).a TLR2 agonist.Cell proliferation was detected by MTT colorimetric assay and the suitable concentrations of PGN were determined.The mRNA and protein expressions of Ki67.TLR2.NF-kB p65 and TGF-α were detected by real-time quantitative PCR and Western blot.respectively,in keratinocytes treated witll PGN of 0,1.25,2.5 and 5 μg/mL.Antibody blocking test was utilized to evaluate the effect of blocking TLR2 with specific anti-TLR2 neutralizing monoclonal antibody before incubation with PGN on the expressions of Ki67,TLR2,NF-KB p65 and TGF-α by keratinocytes.Results The proliferation of kemtinocytes was significantly promoted by the incubation with PGN of 1.25,2.5 and 5μg/mL for 24 hours (all P＜0.05),which also increased the expression of Ki67 protein,TLR2 mRNA and protein,and NF-KB p65 protein.Further more,the mRNA expression of Ki67 in keratinocytes was elevated bv PGN of 1.25 and 2.5μg/mL,the mRNA expression of NF-KB p65 elevated by PGN of 1.25μg/mL,and the expressions of TGF-αprotein and mRNA elevated by PGN of 1.25 and 5μg/mL (P＜0.05).The mRNA and protein expressions of Ki67,TLR2,NF-kB p65 and TGF-αwere all inhibited by the blocking of TLR2 before incubation with PGN (a11 P＜0.05).Conclusion Activation of TLR2 bv PGN could induce the over-proliferation of human keratinocytes,likely through promoting NF-rB activation and TGF-α expression.

Objective To investigate the effect ofnarrow-band ultraviolet-B(NB-UVB)(311 nm)on dendrite formation in B16 melanoma cells.Methods B16 melanoma cells were irradiated with various doses of NB-UVB(0,25,50,100,200,300 mJ/cm2).Atier additional culture of varying durations,irradiated cells were harvested and subjected to the observation of morphological changes and cell cytoskeleton F-actin microfilaments by phase contrast microscopy and laser scanning confocal microscopy(LSCM).respectively,and to the detection of cell proliferation bv MTT colorimetric assay.Pull down assay was performed to detect the activity of GTP-RhoAA and GTP-Rac1 in B16 cells before and after UVB irradiation.Results Twenty-four hours after irradiation with UVB of 100 mJ/cm2.an increase was observed in the cell body of B16 cells which appeared in sphericity,as well as in the number of dendrites(P＜0.01)which showed a branch-like appearance.compared with non-irradiated cells which had 2-3 dendrites and obscure branches.LSCM revealed that F-actin microfilaments in B16 cells were well organized with clear textures before irradiation;after irradiation wim NB-UVB of 100 mJ/cm2.stress fibers were disassembled and disrupted and the texture became unclear,which was observed as early as 30 minutes and became more and more evident,and at 6 hours the stress fibers displayed a clumping appearance with obscure textures.Following the irradiation with NB-UVB of 100 mJ/cm2,the expression level of GTP-Rac 1 protein increased at l 5 minutes,and.at 30minutes,reached 2 times of that observed in nonirradiated cells,then decreased a liale,but still remained elevated at 60 minutes and 120 minutes,compared to unirradiated cells;meanwhile.the level of GTP-RhoA dropped a little at 30 minutes,then gradually increased and,at 120 minutes.reached 1.6 times of that observed in unirradiated cells.Conclusion Narrow-band UVB(311 nm)can promote dendrite formation.likely via regulating the expression of GTP-Racl and GTP-RhoA in B16 melanoma cells.

Objective: To observe the effect of hypoxia on changes of proliferation ability of cultured human periodontal ligament fibroblasts (HPLFS) in vitro. Methods: HPLFS were randomly divided into two groups (experimental group and control group) by different oxygen concentrations. The oxygen concentration of control group was 21%. The oxygen concentrations of experiment group were 10%, 5% and 2%. The proliferation ability of HPLFS was detected by MTT colorimetric assay. The cell ultrastructure was observed by transmission electron microscope (TEM). Results: MTT assay results showed that compared with the control group, at the 12 h and 24 h, cell proliferation was enhanced with the hypoxia degree. At 24 h, cell proliferation showed significant differences. At 48 h and 72 h, proliferation of the cultured HPLFS in severe hypoxia group reduced significantly. Observed by TEM, at 24 h, not only the number of mitochondria, rough endoplasmic reticulum but also cell process increased in the cultured HPLFS in severe hypoxia group. At 72 h, the number of lysosome increased and the cell structure degenerated. Conclusion: Long-time severe hypoxia may lower the repair and remodeling abilities of periodontium, which might be one of the important etiological factors of periodontal disease under condition of high altitude.

Objective : The patients with inguinal hernia were treated with plug mesh hernia repair. Methods:The hernia sacs were isolated and dissected back to the internal ring. The unoperated sacs were allowed to drop back through the internal ring into the abdominal cavity. A cone-shaped mesh hernia plug is inserted tapered end through ring and placed into position just beneath the crura. All our repairs were reinforced a second piece of flat was placed from the pubic tubercle, overlying the direct space. Results : Com-paired with conventional suture surgical techniques, a plug repair uses less disscection and ensures tenssion free hernioplusty. Conclusion : We believe that the two factors are the most important reseasons for greater patients confort, rapit rehabilitation, decreased recurrence and lessened overall complication rates with the mesh hernia plug techniques.

Objective:To construct evaluation indicators for the effectiveness of curriculum ideology and politics education in medical colleges and universities based on the Center for the Study of Evaluation (CSE) model.Methods:Based on the CSE-based theoretical framework of "needs evaluation, program evaluation, formative evaluation, and summative evaluation", semi-structured interviews were conducted to select indicators. The Delphi method was used to conduct two rounds of questionnaire-based consultation with 29 experts to establish a set of indicators for evaluating the effects of curriculum ideology and politics teaching of medical colleges and universities. The priority diagram was used to calculate and determine the weight of each index.Results:The authority coefficient of the 29 experts included in this study was 0.85. The Kendall's coefficients of concordance for the two rounds of expert consultation were 0.361 and 0.577 ( P<0.05), respectively. Finally, an evaluation system for the effectiveness of curriculum ideology and politics teaching was formed, including 4 first-level indicators, 9 second-level indicators, and 18 evaluation observation points. The 4 first-level indicators were "implementation objectives", "implementation plans", "implementation process", and "implementation effects". Conclusions:The CSE model is suitable as a theoretical framework for constructing the evaluation system of curriculum ideology and politics teaching in medical schools, which employs scientific indicator construction methods, follows the basic principles of course evaluation, and conforms to the current concept of ideological and political construction of medical curricula, showing certain feasibility and guiding significance.

Objective:To investigate the efficacy of different laparoscopic surgeries for gastrointestinal stromal tumors (GIST) of gastric cardia and fundus.Methods:The retrospective cohort study was conducted. The clinicopathological data of 251 patients with GIST of gastric cardia and fundus who underwent laparoscopic radical resection in 14 medical centers, including Guangdong Provincial People′s Hospital et al, from December 2007 to December 2021 were collected. There were 123 males and 128 females, aged 58(24,87)years. Observation indicators: (1) treatment; (2) clinicopathological data of patients undergoing different laparoscopic surgeries; (3) subgroup analysis for special laparoscopic techniques. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the t test or ANOVA. Measure-ment data with skewed distribution were represented as M( Q1, Q3), and comparison between groups was conducted using the Mann-Whitney U test or Kruskal-Wallis H test. Count data were described as absolute numbers or percentages. Comparison of ordinal data was conducted using the rank sum test. Results:(1) Treatment. Of the 251 patients,202 cases underwent gastric wedge resection, 26 cases underwent special laparoscopic techniques including 10 cases with serotomy and dissection and 16 cases with transluminal gastrectomy, 23 cases underwent structural gastrectomy including 6 cases with total gastrectomy and 17 cases with proximal partial gastrectomy. There were 24 patients had postoperative complications after surgery. (2) Clinicopathological data of patients undergoing different laparoscopic surgeries. The gender (male, female), age, tumor diameter, operation time, volume of intraoperative blood loss, length of incision, time to postoperative initial whole liquid food intake, time to postoperative initial semi-liquid food intake, duration of postoperative hospital stay, cases with perioperative complications, cases with mitotic count as ≤5/50 high power field, 6?10/50 high power field, >10/50 high power field, cases be classified as very low risk, low risk, medium risk, high risk according to the National Institutes of Health risk classification, cases with tumor located at fundus and gastric cardia were 93, 109, (59±11)years, 3.50(0.40,10.00)cm, 88.00(25.00,290.00)minutes,20.00(25.00,290.00)mL, 4.00(2.00,12.00)cm, 3.00(1.00,9.00)days, 4.00(1.00,16.00)days, 5.00(1.00,18.00)days, 14, 164, 31, 7, 47, 83, 50, 22, 30, 172 in patients undergoing gastric wedge resection, respectively. The above indicators were 19, 7, (49±14)years, 2.55(0.20,5.00)cm, 101.00(59.00,330.00)minutes, 27.50(2.00,300.00)mL, 4.50(0,6.00)cm, 2.50(1.00,10.00)days, 4.00(1.00,16.00)days, 6.00(1.00,18.00)days, 3, 20, 5, 1, 15, 5, 2, 4, 24, 2 in patients undergoing special laparos-copic techniques, and 11, 12, (52±10)years, 5.00(0.80,10.00)cm, 187.00(80.00,325.00)minutes, 50.00(10.00,300.00)mL, 6.00(4.00,12.00)cm, 4.00(2.00,8.00)days, 6.00(3.00,14.00)days, 8.00(2.00,18.00)days, 7, 11, 5, 7, 2, 6, 6, 9, 13, 10 in patients undergoing structural gastrectomy. There were significant differences in the above indicators among the three groups of patients ( χ2=6.75, F=10.19, H=17.71, 37.50, 35.54, 24.68, 16.09,20.20, 13.76, χ2=13.32, Z=28.98, 32.17, χ2=82.14, P<0.05). (3) Subgroup analysis for special laparoscopic techniques. The time to postoperative initial whole liquid food intake, time to postoperative initial semi-liquid food intake, classification of tumor location (endophytic type, exophytic type, parietal type) were 4.50(1.00,10.00)days, 8.00(3.00,12.00)days, 0, 8, 2 in patients undergoing serotomy and dissection, versus 2.00(1.00,4.00)days, 3.00(1.00,6.00)days, 16, 0, 0 in patients undergoing transluminal gastrectomy. There were significant differences in time to postoperative initial whole liquid food intake, time to postoperative initial semi-liquid food intake between them ( Z=-2.65, -3.16, P<0.05); and there was a significant difference in classification of tumor location between them ( P<0.05). Conclusions:Gastric wedge resection is the most commonly used laparoscopic technique for GIST of gastric cardia and fundus. The application of special laparoscopic techniques is focused on the GIST of cardia to preserve the function of the cardia.

OBJECTIVE：To establish a host specific method for the qual ity evaluation of Taxillus chiueusis by evaluating the quality of T. chiueusis from different hosts sources. METHODS ：HPLC was adopted with CAPCELL PAK C 18 MGⅡ column， mobile phase consisted of methanol- 0.2％ phosphoric acid ，volume flow 1.0 mL/min（gradient elution ），detection wavelength of 254 nm，column temperature of 30 ℃. Totally of 16 batches of T. chiueusis from different hosts sources were collected as sample （4 batches from tea host ，maple host ，willow host and mulberry host respectively ）. HPLC characteristic chromatogram was established with TCM Chromatogram Fingerprint Similarity Evaluation System （2004A edition ），and similarity evaluation was performed. The peak was identified by comparison with the reference substance. IBM SPSS 19.0 software was used for cluster analysis and principal component analysis. RESULTS ：Totally 11 common peaks were demarcated ，peak No. 8，10，11 were identified as rutin ，quercetin and quercitin. The similarity of 16 batches of samples was more than 0.9. The chemical components of T. chiueusis from different hosts sources were basically the same （RSDs of relative time of commom peaks were 0.03％-0.40％）， but the contents of the same component were quite different （RSDs of relative peak area of commom peaks were 27.00％-64.20％）. By cluster analysis ，16 batches of T. chiueusis from different hosts sources were divided into 3 types. The results of principle component analysis showed that quercetin ，quercitin and rutin had significant effect on the quality of T. chiueusis ，which could be used as the quality evaluation index ，and the whole quality of maple host was the best （the highest comprehensive score ）. CONCLUSIONS： HPLC fingerprint combined with chemometrics can be used to evaluate the quality of T. chiueusis from different hosts sources.