Objective To evaluate the apical sealing ability of iRoot SP root canal sealer in oval-root canal. Methods After root canals were instrumented by Mtwo, 28 premolars with oval-root canal were randomly divided into 2 groups, 14 teeth in each. The root canals were obturated with AH Plus (group A) and iRoot SP (group B) by modified continuous wave condensation technique. The apical leakage was evaluated by dye penetration method and transparent teeth technique. Results Mean depth of leakage was (0.92 ± 0.26) mm for group A and (0.84 ± 0.40) mm for group B. There was no significant difference between the two groups (t=0.506, P > 0.05). Conclusion The apical sealing ability of iRoot SP is equivalent to AH Plus in oval-root canal.

Objective To investigate the radiosensitizing effects of gefitinib at different administration time. Methods Gefitinib was administered to A549 lung cancer cells in three different ways (method 1, 24 h before irradiation ;method 2, upon irradiation and method 3, 24 h after irradiation). Cell-surviving rates were evaluated by the colony-forming assays. Cell apoptnsis and cell-cycle distributions were detected by the flow cytometry (FCM). Protein expression of p21, Cdc25c, Bcl-2, Bax, Rad51 and phosphorylated DNA - PKcs (phnspho - DNA - PK) were measured with the Western blot analysis. Results The sensitizing effect ratio (ratio of D_0 value) was 2.23, 1.51 and 1.30 with method 1, 2 and 3, respectively. A higher apoptosis rate and more G_2/M phase arrest were observed with method 1 when compare with method 2 or 3. With the similar tendency, the protein level of p21, Cdc25c, Bcl-2, Bax, RadSl and phospho-DNA-PK changed distinctly. Conclusions Radiosensitizing effects are obtained in all three methods, with gefitinib delivered before irradiation being the best.

Objective To study the capacity of dentifrice containing hydroxyapatite (HA) particles with various grain sizes on the sorption of Cu (Ⅱ) ion from aqueous solution. Methods Three groups of dentifrice suspensions containing 3% HA particles with 60 nm grain size, 3% HA particles with 12 μm grain size, and blank dentifrice were prepared with serial concentrations. Copper ion solutions with initial concentration of 4.0 mg/L were mixed with dentifrice suspensions respectively and then been kept still for 24 hours. The residual copper ion concentration of the supernatant was measured by inductively coupled plasma emission spectrometer and the sorption rate of copper ion was calculated. Results The residual copper ion concentration of the supernatant decreased with increase of the concentration of dentifrice suspensions. The sorption rate of copper ion of dentifrice containing 60 nm HA was highest among the three groups. Conclusion Nano HA should be added into dentifrice to enhance the sorption capacity of copper ion from aqueous solution.

Objective: To explore the role of apoliprotein D (APOD) in the proliferation and migration of human dental pulp cells (DPCs) and to provide a basis for the use of APOD to promote pulp regeneration. Methods: APOD expression in human dental pulp cells was inhibited by siRNA. The inhibition effect of APOD was confirmed by qPCR and Western blot. After APOD inhibition, colony formation experiments and CCK8 assays were employed to confirm the proliferation ability of dental pulp cells. Transwell assays were used to verify the cell migration ability after the inhibition of APOD expression. Results : After inhibiting APOD expression, the colony formation rate in the si-apod group was reduced compared with the NC group, and the difference was statistically significant (t=7.624, P=0.002). The CCK8 experiment showed that the OD value in the si-apod group decreased at 3, 5 and 7 d compared with that in the NC group (P < 0.05). Transwell results showed that the number of cell divisions was 57.25 ± 4.03 in the si-apod group and 154.50 ± 8.39 in the NC group, and the difference was statistically significant (t=10.45, P < 0.001). Conclusion Inhibition of APOD expression in dental pulp cells inhibits their proliferation and migration ability.

Objective:To study the feasibility of magnetic resonance imaging(MRI)technique with amide proton transfer(APT)in predicting the prognosis of cerebral stroke.Methods:A total of 71 patients with acute cerebral stroke who admitted to the Nanjing First Hospital,Nanjing Medical University from September 2022 to May 2023 were selected.All of them underwent the test of National Institute of Health Stroke Scale(NIHSS),and received the MRI examination with chemical exchange saturation transfer(CEST).According to the modified Rankin scale(mRS)values of 1-month follow-up,they were divided into favorable recovery group(mRS<2,44 cases)and poor group(mRS≥2,27 cases).The asymmetric magnetization transfer ratio(MTRasym)image(APT)was obtained by analyzing data with special software.And then,the difference(△APTw)of APT values between ischemic zone and contralateral normal tissue was further calculated.The △APTw values of two groups were compared and analyzed,and the Pearson correlation analysis was adopted to analyze the correlation among △APTw,NIHSS and mRS.The receiver operating characteristics(ROC)curve was drawn,and the area under curve(AUC)of ROC curve was calculated.Results:There were significant positive correlations among △APTw,NIHSS and mRS scores(R2=0.659,0.522,P<0.001),and the differences of △APTW,NIHSS and mRS scores between the favorable recovery group and poor group were significant(t=5.73,6.36,13.92,P<0.05),respectively.The AUC value was 0.886,and the sensitivity and specificity of prediction were respectively 77.8%and 95.5%.The positive and negative predictive values were respectively 91.3%and 87.5%.Conclusion:APT imaging technique has feasibility in predicting the prognosis of acute cerebral ischemic stroke.

OBJECTIVE： To study the dose-time-effect relationship of Tibetan medicine Rannasangpei in cerebral ischemic- reperfusion injury model rats with intragastric administration. METHODS： The rats were randomly divided into sham operation group （normal saline， 10 mL/kg）， model control group （normal saline， 10 mL/kg）， positive control group （nimodipine， 30      mg/kg）， Rannasangpei different dose groups （0.52， 1.04， 2.08， 4.17， 8.33， 16.67， 33.34， 66.68， 133.36， 266.72 and 533.44    mg/kg）， with 18 rats in each group. Each group was given relevant medicine intragastrically once； 25 min after intragastric administration， cerebral ischemic-reperfusion injury model was established with suture-occluded method in those groups except for sham operation group. 24， 48， 72 h after cerebral ischemia， neuroethology of rats were graded in each group. The rate of cerebral infraction was detected to evaluate the optimal effective time， the optimal dose （Dmax） and maximal effect （the rate of minimum cerebral infraction， Emax） of Ratnasampil at different periods of cerebral ischemia. Dose-time-effect relationship of Rannasangpei dose with the rate of cerebral infraction was fitted with Thermo Kinetica 5.1 software. The area under curve （AUClast） and retention dose （MRTlast） of dose-effect curve were calculated， and detect the levels of SOD and MDA. RESULTS： Compared with sham operation group， the neurobehavior of model group was significantly abnormal （P＜0.05 or P＜0.01）， and the rate of cerebral infarction was significantly increased （P＜0.01）； the level of SOD was decreased significantly （P＜0.01， 48 h）， and the level MDA was increased significantly （P＜0.05， 48 h）. Compared with model control group， there was no significant change in neurobehavioral abnormalities in the nimodipine group （P＞0.05）， and the rate of cerebral infraction was decreased significantly （P＜0.01， 24， 48 h）. The level of SOD in rats were increased significantly （P＜0.01， 48 h）， while the level MDA decreased significantly （P＜0.05， 48 h）. Rannasangpei 2.08-33.34 mg/kg could significantly improved neurobehavioral abnormalities （P＜0.05， 24 h）； 24 h after cerebral ischemia， the rate of cerebral infraction was decreased significantly in Rannasangpei 4.17-133.36 mg/kg group （the lowest is 33.34 mg/kg group， P＜0.05 or P＜0.01）. The level of SOD in rats were increased significantly in 33.34-533.44 mg/kg groups （P＜0.05）. the level MDA was decreased significantly in 0.52-2.08， 8.33， 33.34， 266.72 and 533.44 mg/kg groups （P＜0.05）. Dmax was 33.34 mg/kg， Emax was 3.02％， AUClast was 5 141.76 mg/kg and MRTlast was 329.161 mg/kg. 48 h after cerebral ischemia， the rate of cerebral infraction was decreased significantly in Rannasangpei 2.08-133.36 mg/kg groups （the lowest is 66.68 mg/kg group， P＜0.05 or P＜0.01）， while the level of SOD was increased significantly in 1.04-533.44（except for 4.17）mg/kg groups （P＜0.05）. The level of MDA was decreased significantly in 16.67-66.68， 533.44 mg/kg groups （P＜0.05）， Dmax was 66.68 mg/kg， Emax was 2.13％， AUClast was    5 219.36 mg/kg and MRTlast was 340.521 mg/kg. 72 h after cerebral ischemia， the rate of cerebral infraction and the level of MDA had no significant decreased in Rannasangpei groups （P＞0.05）， and the levels of SOD had no significant increase （except for 0.52 mg/kg group， P＞0.05）. CONCLUSIONS： The optimal effective time of Rannasangpei for the treatment of cerebral ischemia-reperfusion injury in rats is 48 h， and the Dmax is 66.68 mg/kg. The improvement mechanism may be related to increase the level of SOD and decrease the level of MDA.

OBJECTIVE: To study the effect of nanohydroxyapatite (nHA) for promoting surface mineralization of demineralized dentin discs and adsorption of lead ions in simulated sewage water. METHODS: Sixty dentin disks were prepared from freshly extracted teeth with intact crown (including 30 premolars and 30 molars) and treated with 10% citric acid for 2 min to simulate dentinal tubules with dentin hypersensitivity. The etched dentin discs were brushed with distilled water, 0.2 g HA or 0.2 g nHA for 2 min twice a day for 7 consecutive days, after which scanning electron microscopy (SEM) was performed and calcium and phosphorus contents in the dentin discs were detected using EDS. Lead ion adsorption capacities of HA and nHA were tested by mixing 1 mL serial concentrations of HA and nHA suspensions with 50 mL lead ion solutions (1.0 mg/L). After 24 h, the residual lead ion concentration in the supernatant was measured using ICP to calculate lead ion adsorption rate and adsorption capacity of the materials. RESULTS: SEM showed a smooth surface and empty dentin tubules in the acid- etched dentin dics. The dentin dics treated with HA were covered with masses of particles that loosely attached to the surface, and the diameter of the dentin tubules was reduced. In nHA group, the dentin discs showed a fine and homogeneous surface clogging with a tight attachment, and the dentin tubule diameter was obviously reduced. Daily brushing with HA and nHA, especially the latter, significantly increased calcium and phosphorus contents on the surface of the dentin dics ( < 0.000). In lead ion adsorption experiment, the lead ion adsorption rate of HA decreased as its concentration increased with the highest adsorption rate of 83.01%; the adsorption rate of nHA increased with its concentration until the adsorption equilibrium was reached, and its highest adsorption rate was 98.79%. A good liner relationship was found between the adsorption ability and concentration of HA. CONCLUSIONS Compared with HA, nHA has a better capacity for surface mineralization of acid-etched dentin discs and also a better ability of lead ion adsorption.