Cerebral ischemia and the aftermath of reperfusion form a hypoxic/hyperoxic sequence of events that can trigger DNA damage in neurons of central nervous system. Neuronal apoptosis will happen without immediate DNA repair. APE/Ref-1 is a multifunctional protein involoved in DNA base excision repair pathway and in redox reguiation of DNA-binding activity of AP-1 family members, which may play an important role in protection of postischemic neuronal damage.

Objective To evaluate the clinical effect of the use of pathfile and protaper nickel-titanium instruments for machine in root canal preparation.Methods A total of 200 patients suffering from pulpitis and periapical that needs root canal treatment was randomly divided into two groups according to treatment order (100 patients/each group).The experimental group was used pathfile and protaper in root canal preparation,and filled with warm gutta vertical condensation.The control group was used protaper root canal preparatory standards method,and filled with warm gutta vertical condensation.The required time of two sets of root canal preparation and the number of equipment broken were recorded,and X-ray film at the preoperation intraoperation and postoperation were used to evaluate effect of preparation and root filling.Results In the root canals prepared of the two groups,no issued offset,no side wear,no step-forming,and no position changed of the apical foramen were occurred,which was consistent with preperative X-ray film.One case was occurred fracture of instrument in the experimental group and the control group,it was Slfile.Tooth position was right mandibular,second molar nearly the root apical 1/3,and upper left second molar mesial buccal root apical position.The root canal preparation time of experimental group was significantly shorter than the control group[the front teeth:(4.73 ± 1.12) min vs (6.32 ± 1.84) min,t =2.243,P ＜0.05; the premolars:(7.83±1.23)min vs (10.25±2.68)min,t =2.475,P ＜0.05; the molars (10.14 ± 1.18) min vs (15.43 ± 5.94) min,t =2.991,P ＜ 0.01].Postoperative X-ray showed that 2 cases were occurred small amount of paste overfilled,the root canal closed tight,no less filling; and 3 cases of the control group occurred paste overfilled,no less filling too.Conclusions The use of nickel-titanium instruments pathfile and protaper for machine in root canal preparation is feasible,and improves the efficiency of root canal preparation.

Objective　To analyze the partial correlation problems by multilevel bivariate models.Methods　Multilevel bivariate models.Results　The results of correlation analysis with multilevel bivariate models is same with traditional methods,but the former is more quick and simple.Conclusion　Multilevel bivariate models are effective methods in analyzing the partial correlation problems.

Objective To investigate the possibility of pulp regeneration of different irreversible pulpitis with absorbable gelatin sponge as the scaffold,and dental seed cells,induced molecules and MTA closed.Methods 150 patients with irreducible pulpitis,who were removed the crown infection pulp and retained the root living pulp,according to the visiting sequence,were randomly divided into two groups.The experimental group was given absorbable gelatin sponge as the scaffold and MTA closed.The control group was given calcium hydroxide coverage.The symptoms situation and pulp situation were observed.Results 6 months after surgery,the success rate of acute pulpitis and chronic closed pulpitis in the experimental group was 76.5％ and 47.0％,which were significantly higher than those of the control group (14.3 ％,8.8％) (P ＜ 0.01).In the experimental group,the success rate of chronic hyperplastic pulpitis and chronic ulcerative pulpitis was 33.0％ and 35.0％,which were higher than those of the control group(9.1％,6.0％),but the differences between the two groups were not statistically significant (P ＞ 0.05).Conclusion Pulp regeneration in vivo is possible with absorbable gelatin sponge as the scaffold and MTA,pulp regeneration of acute pulpitis and chronic closed pulpitis are more likely to induce.

It is well known that the nitrate and nitrite from environment is causally related to infant methemoglobinemia and esophageal cancer.In the past three decades,there was also much evidence to reveal that nitrite and nitrate from drinking water or diet were potentially related to human congenital malformations.The present paper introduced the exposure and transformation of nitrate,nitrite and N-nitrosocompound from environment and the evidences of investigation about relationship between these compounds and human congenital malformations.

Objective To explore the value of chemosensitivity assay in vitro on breast cancer.MethodsIn vitro chemosensitivity of 6 species of chemotherapeutic agents applied to 38 cases of breast cancer patients were detected by tissue culture-end point staining-computer image analysis(TECIA).ResultsThe sensitivity to chemotherapeutic agents commonly used in the breast cancer level from high to low was as follow:Doxorubicin(ADM),Paclitaxel(TAX),Vinorelbine(NVB),Cyclophosphamide(CTX),Cisplatin(DDP)and Fluorouracil(FU).ConclusionDrugs sensitivity experiment of cancer in vitro by TECIA has an important value to instruct clinical medication and individual chemotherapy for breast cancer.

Objectives To evaluate the effectiveness of transcarotid artery chemotherapy for gliomas after surgery, and selection of drug, avenue of administration, and optional time for the therapy. Methods Beginning from 4 to 30 days after operation, Nimustine (ACNU, Japan) 2.5mg/kg was injected per carotid artery, once every week for three times as one course. A second course of treatment was given after an interval of 4 to 6 weeks. Results With the above regime, the effect was marked in 39 cases (18.8%), fairly effective in 44 cases (20.8%), only slightly effective in 59 cases (27.8%), no effect in 61 cases (28.8%), and failure in 5 cases (2.4%), the mean survival time was nearly 100 weeks. Conclusion Transcarotid artery chemotherapy for gliomas is helpful in prolonging survival period, with little side effects, easy to carry out, less expensive, and better accepted by the patients.

Objective: To prepare piroxicam nanostructured lipid carrier and investigate its transdermal absorption behavior in vitro. Methods:Piroxicam nanostructured lipid carrier was prepared by a melt-emulsion ultrasonication and low temperature-solidifica-tion method. The physicochemical properties such as appearance, morphology, particle size distribution, PdI and zeta potential of pi-roxicam nanostructured lipid carrier were evaluated. The transdermal absorption in vitro was investigated using Franz diffusion cells. Results:Piroxicam nanostructured lipid carrier was clear and transparent with small spherical shape as seen under a transmission elec-tron microscope. The particle size distribution, PdI and zeta potential was (106. 4 ± 31. 6) nm, (0. 217 ± 0. 07) and ( -31. 6 ± 2. 5) mV, respectively. Piroxicam nanostructured lipid carrier had higher cumulative transdermal amount in 12 h than piroxicam solution. Conclusion:The nanostructured lipid carrier can remarkably improve piroxicam permeation into skin, which provides reference for the new dosage form for the topical use of piroxicam.

In order to explore a dose distribution verification procedure of intensity modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC) and establish its evaluation criteria, we performed 35 two-dimensional (2D) patient-specific IMRT verifications over the year 2006. The percent of pixels passing gamma and the normalized agreement test (NAT) index were mainly used to represent the agreement between the measured and computed dose distributions with three criteria (2%/2 mm, 3%/3 mm and 5%/3 mm) as recommended in the literature. The results were that all cases passed through verifications with three criteria except that the NAT index of one case was beyond the limitation, and the three tolerance levels of 2%/2 mm, 3%/3 mm and 5%/3 mm produced similar clinical verification results but led to different percent of pixels passing gamma and NAT index. Our data showed that the percent of pixels passing gamma and the NAT index were complementary to evaluate future IMRT verifications as two significant metrics. Due to the influence of the noise and the trait of the software, we considered an IMRT plan as acceptable in case of the percent of pixels passing gamma >95% and the NAT index <5 with the 5%/3 mm criteria for IMRT patient-specific quality assurance (QA).

Objective To explore the dose rate response characterization of four kinds of dosimeters for clinical application.Methods Within the range of 100-600 cGy/min,the dose rate responses of the PTW 0.6 cm3 ion chamber,0.015 cm3 ion chamber,Matrixx Evolution 2D diode array and MapCHECK 2D diode array under the same measuring conditions were measured.The dose rate response of the PTW 0.6 cm3 ion chamber under different energy and working voltage were analyzed.Results All ionization chambe.r types of measured equipment showed certain dose rate dependence for 6 MV X-rays.All the differences were below 1％.The dose rate dependence disappeared for 15 MV X-rays.The 2D diode array had strong dose rate dependence and the response difference was about 2％.Conclusions It is necessary to test and analyze the dose rate response of the measured equipment in treatment technology with dose rate varying,in order to ensure the precision of daily calibration and dose verification.