Objective:To compare the fracture resistance of roots of mandibular premolar with different apical preparation diameters.Methods:Sixty single-rooted single canal permanent mandibular premolar teeth extracted newly for orthodontic reason without immatureness,fracture or cracks were selected,with a curvature less than 10°,and internal length:short diameter of less than 2 at a level 5 mm from the apex.All the teeth were decoronated,leaving roots 13 mm in length.The initial apical file size for the teeth was ≤ 15#.The roots were assigned to 6 groups based on weights with random block design.Group A:blank control group,no instrumentation was performed.Groups B-F:the master apical file (MAF) was 40#,45#,50#,55# and 60#,respectively.In the five experimental groups the roots were instrumented using hand files with step-back technique at 1 mm increments,resulting in a taper of 0.05.The irrigant used was distilled water.After mounted in acrylic resin,all the teeth were subject to vertical loading using an Instron testing machine until fractured.The occurrence of fractures was detected when the applied load suddenly decreased.The fracture load values and fracture modes were recorded.Oneway ANOVA and post-hoc Tukey test were used to determine the difference of fracture load values between the groups (P ＜ 0.05).Chi-square tests were used to compare the modes of root fracture.Results:Five experimental groups exhibited lower fracture load values than that of control group [(1 444 ± 155) N].The mean fracture load values for roots instrumented to an apical diameter of 50# [(1 027 ± 128) N],55# [(994 ± 150) N] and 60# [(983 ± 166) N] were significantly lower than that of control group and 40# group [(1 339 ± 131) N] and 45# [(1 287 ± 144) N] (P ＜0.05).Buccal-lingual fracture,mesio-distal fracture and compound fracture occurred 55％,13％ and 32％,respectively.No difference of fracture mode was detected in the six groups.Conclusion:The fracture resistance reduced significantly when the roots were instrumented to an apical diameter of 50# or larger.

Objective To Analyze the immunity to secondary infection in the elderly with severe acute pancreatitis.Methods Totally 105 old patients were included in the present study.The ratio of CD4+ to CD8+,and serum levels of tumor necrosis factor-α (TNF-α),interleukin-6 (IL-6),interleukin-10 (IL-10),and interleukin-4 (IL-4) were determined by flow cytometer analysis or ELISA within 3 days after diagnosis of secondary infection.Results Among 105 old patients,58 cases experienced secondary infection.At 3th day after severe acute pancreatitis,the levels of TNF-α,IL-6,IL-4,IL-10,CD4+,CD8+ and CD4+/ CD8+ were (81.3±5.5)ng/L,(141.2±13.7)ng/L,(61.1±7.4) ng/L,(153.8 ±15.2) ng/L,(43.5±5.5)％,(20.7±2.9)％ and (2.4±0.3) in infection group,as compared with those of (50.8±4.7)ng/1,(81.4±11.7)ng/L,(30.8±7.8)ng/L,(100.3± 13.8)ng/L,(31.6±4.6)ng/L,(29.7±3.5)and (1.1±0.4)in control group,respectively,with statistically significant differences betwveen the two groups (t=7.30,6.51,4.87,4.52,2.88,3.41,4.26,all P＜0.05).At 28th day after SAP,the levels of TNF-α,IL-6,IL-4,IL-10,CD4+,CD8 ± and CD4+ /CD8+ were (29.3±5.8)ng/L,(51.7±7.9)ng/L,(33.8±5.1)ng/L,(82.6±9.5)ng/L,(22.1±3.3)％,(47.1±4.3)％ and (0.6±0.3) in infection group,as compared with those of (44.4±5.5)ng/L,(82.2±7.1)ng/L,(65.3±5.5)ng/L,(109.1±9.5)ng/L,(40.5±2.7)ng/L,(33.4±4.5)ng/L and (1.8±0.4) in control group,respectively,showing statistically significant differences between the two groups(t=3.26,4.93,7.32,3.43,7.41,3.81,4.33,all P＜0.05).Conclusions An early excessive immune response and subsequent immune injury is closely related to secondary severe acute pancreatitis.

Objective To investigate the effects and the migration mechanisms of stromal derived factor-1 (SDF-1) and CXC chemokine receptor-4 (CXCR-4) in rats with white matter damage treated with human umbilical cord mesenchymal stem cells (hUC-MSCs).Methods A total of 108 three-day old Sprague-Dawley rats were randomly divided into the experimental group,control group and sham group.The left common carotid artery was ligated and then exposed to hypoxia of 6％ O2 and 94％ N2 in rats in the experimental and control groups.Rats in sham group were neither ligation nor hypoxia.After 24 hours,rats in the experimental group were administered 0.5 ml hUC-MSCs (1 × 106/ml) intraperitoneally,and rats in control and sham groups were administered 0.5 ml saline by the same way.Immunohistochemistry and reverse transcription-polymerase chain reaction were used to determine the expression of SDF-1 and CXCR-4 protein and mRNA in 5-,7-and 14-day-old rats.Analysis of variance and the LSD test were used for statistical analysis of the data.Results HE staining showed that,in 14 day-old rats of the experimental group,bilateral cerebral ventricles were similar with no cellular edema or necrocytosis.In the sham group,bilateral cerebral ventricles were also normal.However,in the control group,ventriculomegaly,cellular degeneration and necrocytosis were observed on the left side.On the 5th,7th and 14th day,SDF-1 protein levels were 0.15±0.06,0.24±0.01 and 0.12±0.01,and CXCR-4 protein levels were 0.35±0.16,0.60±0.21 and 0.72±0.25,respectively,in the experimental group; SDF-1 protein levels were 0.13 ± 0.01,0.16± 0.01 and 0.08± 0.01,and CXCR-4 protein levels were 0.18 ± 0.04,0.17 ± 0.09 and 0.25 ± 0.06,respectively,in the control group,and all were higher than those in the sham group (SDF-1 protein levels were 0.03 ± 0.01,0.04± 0.01 and 0.02±0.01; and CXCR-4 protein levels were 0.04±0.02,0.05±0.03 and 0.05±0.03,respectively) (LSD test,all P＜0.05).SDF-1 protein increased to a peak on the 7th day and decreased on the 14th day in the experimental group,however,these values were both higher than those in the control group (LSD test,both P＜0.05).CXCR-4 protein increased on the 5th day and continued to increase up to the 14th day in the experimental group,and these values were higher than those in the control group at the three time points (LSD test,all P＜0.05).In 5-,7-and 14-day-old rats,SDF-1 mRNA levels were 3.52 ± 0.33,4.18± 0.28 and 2.60± 0.21,respectively,in the experimental group,which were higher than those in the control group (2.07± 0.34,3.73 ± 0.28 and 2.08± 0.15,respectively),and were even higher than those in the sham group (0.99±0.17,1.00±0.16 and 1.31 ±0.32,respectively) (LSD test,all P＜0.05).In the experimental group,SDF-1 mRNA levels reached a peak on the 7th day,and on the 14th day,it decreased to the level lower than that on the 5th day (LSD test,all P＜0.05).In the control group,SDF-1 mRNA levels also reached a peak in 7-day-old rats,but not in 14-day-old rats,which was similar to 5-day old rats (LSD test,9＞0.05).In 5-,7 and 14-day-old rats of the experimental group,CXCR-4 mRNA levels were 1.32±0.29,1.75±0.36 and 2.33±0.49,respectively,higher than those in the sham group (1.00±0.16,0.94±0.16 and 0.81±0.14,respectively) and the control group (0.97±0.14,0.97±0.15 and 1.07±0.25,respectively) (LSD test,all P＜0.05).In the experimental group,CXCR-4 mRNA levels were higher in 14-day-old rats than that in 5-and 7-day-old rats (LSD test,both P＜0.05).Conclusions SDF-1/CXCR-4 may play a vital role in the migration of hUC-MSCs homing to damaged brain.

Objective To investigate changes and the significance of Th17/Treg immune imbalance in secondary systemic infection in patients with severeacute pancreatitis.Methods We selected 21 patients with severe acute pancreatitis and secondary systemic infection (infection group),25 patients with severe alone (non-infection group),20 healthy cases undergoing annual health checkup (control group) in this study.The expression levels of Th17/Treg cells and related cytokines were compared between groups.Results There were significant differences in mortality rate and duration of ICU stay between infection group and non-infection group [23.8％ vs.4.0％,(11.3±3.4) d vs.(7.5±2.8) d,x2=3.949,t=2.890,P=0.047 and0.045].The percentages of Th17 cell andTreg cell,Th17/Treg ratio,mRNA expressions of IL-6,IL-17,IL-23,TGF-β and orphan receptor γt were higher in infection and non infection groups than in control group [(26.4 ± 1.2) ％,(12.8 ± 0.9)％ vs.(3.1±0.8) ％;(6.7±1.6)％,(4.2±1.3)％ vs.(1.3±0.4)％;(4.3±1.0)％,(3.2±1.1)％ vs.(2.4±0.9)％;(7.1±0.8)ng/L,(5.3±0.7)ng/L vs.(0.2±0.1)ng/L;(22.9±2.4)ng/L,(15.6±2.8)ng/L vs.(10.3± 1.5)ng/L;(15.7±2.1)ng/L,(10.2± 1.5)ng/L vs.(8.3± 1.4)ng/L;(23.6±2.2)ng/L,(16.3±1.7)ng/L vs.(11.6±1.1)ng/L;(0.052±0.014),(0.035± 0.010) vs.(0.004±0.001);F=15.761,55.745,9.437,102.788,21.038,16.239,36.957,23.924,respectively,P=0.555,0.000,0.014,0.000,0.002,0.004,0.000,0.000].The mRNA expressions of IL-10 and Foxp3-T were lower in infection and non-infection groups than in control group [(6.4±1.1)ng/L,(10.5 ± 2.1) ng/L vs.(15.4±2.0)ng/L;(0.005±0.001),(0.020±0.007) vs.(0.032±0.009),F=18.995 and 20.608,P=0.003 and 0.002].Conclusions The secondary infection can aggravate the Th17 / Treg immune imbalance in patients with severe acute pancreatitis,and extend the ICU hospitalization days.

Objective To study absorption characteristic of dioscin from Dioscorea nipponica Makino extract in rat intestine.Methods Single-pass intestinal perfusion (SPIP) model was used for rat in situ and HPLC was used to determine the concentrations of dioscin.The effects of different intestinal segments,drug concentration and P-glycoprotein (P-gp) inhibitor on intestinal absorption were investigated.Results Dioscin could be absorbed in the whole intestine,the absorption rate constant (Ka) and the apparent coefficient (Papp) of dioscin decreased following the sequence of ileum > duodenum =jejunum > colon.Absorption parameters of dioscin had no significant difference at different concentrations (40,80,120 mg·L-1).There were significant differences in Ka and Papp values between P-gp inhibitor group and no P-gp inhibitor group(P<0.05).Conclusion The saturate phenomena was not observed under the test range of drug concentration,and the absorption mechanism may be passive diffusion transport.Dioscin in Dioscorea nipponica Makino extract may be the substrate of P-gp.

Objective To assess the clinical value of HRCT in diagnosis of cholesteatomatous tympanitis.Methods HRCT findings of 26 patients with cholesteatomatous tympanitis proved by surgery and pathology were analyzed.Results HRCT findings of cholesteatomatous tympanitis included:soft tissue mass in the superior tympanium,tympanal sinus and mastoid(100%,26/26),destruction of the bone includeing ossicles chain (92%,24/26),secutum(46%,12/26),facial nerve canal (54%,14/26);enlargement of the tympaniosinus with sclerosing borders;intracranial complications including temple abscess(1 case),meningitis(1 case).Conclusion HRCT is of great value in diagnosis of cholesteatomatous tympanitis.

Objective To evaluate the therapeutic effects of Lumber continued drainage of cerebrospinal fluid after Key-hole approach operation and craniotomic hematoma elimination on the prognosis of hypertensive in-tracerebral hemorrhage patients. Methods Lumber continued drainage of cerebrospinal fluid after Key-hole ap-proach operation was conducted on 38 hypertensive intracerebral hemorrhage patients. At the 1st month and 6th month after operation, Glasgow coma scale (GCS), Glasgow outcome scale (GOS), Barthel index, language barrier degree evaluation and sports function barrier degree evaluation were measured. The therapeutic effects were observed and compared with 34 patients who were operated by craniotomic hematoma elimination. Results GCS was 6.8± 2.1,6.6±2.3 before operation and 10.5±2.5,8.7±2.2 one week after operation in experimental group and con-trol group respectively; GOS was 3.4±0.3,2.8±0.2 one month after operation and 4.1±0.6,3.2±0.4 six month after operation in experimental group and control group respectively; Bartherl index, language barrier degree and sports function barrier degree were 63.15±11.64,51.76±12.81 and 1.7±0.3,2.3±0.2,2.0±0.3, and 2.6± 0.4 (P<0.05 or P<0.01). Conclusion Lumber continued drainage of cerebrospinal fluid after Key-hole approach operation offers greater help in improving the patients' quality of existence, by which the neurological function recov-ers faster and the patients recover well.

Objective To investigate the alterations in oligodendrocyte and microglia and changes in neurobehavior after human umbilical cord mesenchymal stem cells (HUcMSCs) intervention on the newborn rat model of white matter damage (WMD) induced by hypoxia-ischemia.Methods After the operation of left common carotid artery ligation and 4 h hypoxia (6％ O2 and 94％ N2),twelve three-day-old Sprague-Dawley rats died and the remaining sixty rats were randomly divided into the experimental group and the control group.The first day was 0 to 24 h after birth.Rats of the experimental group were intraperitoneally injected the fourth generation HUcMSCs 1 × 106 (0.05 ml) on the third,fourth and fifth day respectively.At the same time,rats of the control group were intraperitoneally injected phosphate buffer (0.05 ml).Eight rats of each group were executed on the tenth and twenty first day respectively to detect the number of cells positive for myelin basic protein (MBP) and ectodermal dysplasia-1 (ED-1) staining by immunohistochemistry.Three rats of each group were executed on the tenth and twenty first day respectively to detect MBP and ED-1 expression by western blot.Eight rats of each group were weighed and underwent the neurobehavioral evaluation on the twenty eighth day.Data were analyzed using t test.Results On the tenth and twenty first day,the numbers of MBP-positive cells in the experimental group (11.8 ± 4.1 and 23.8± 8.1) were significantly higher than those in the control group (6.7±3.1 and 11.5 ± 5.8,t=-2.81 and 3.49,both P＜0.05) ; and the numbers of ED-1 positive cells in the experimental group (20.8 ± 3.4 and 19.1 ± 2.8) were significantly lower than those in the control group (32.8±4.2 and 29.5±5.2,t=6.23 and 4.93,both P＜0.01).On the tenth and twenty first day,MBP expressions in the experimental group (1.3 ± 0.1 and 1.1 ± 0.1) were higher than those in the control group (0.8±0.0 and 0.6±0.1,t=-7.53 and 6.68,both P＜0.01) ; and the ED-1 expressions in the experimental group (0.6±0.1 and 0.4±0.1) were lower than those in the control group (1.0±0.1 and 0.8±0.1,t=3.09 and 4.90,both P＜0.01).Weight on the seventh,tenth,fourteenth,twenty first and twenty eighth day in the experimental group [(15.0± 1.2),(16.6±0.9),(27.0± 1.6),(44.2±2.3) and (68.1 ±4.2) g] was significantly higher than that in the control group [(12.7 ± 1.6),(13.5 ± 2.0),(23.6 ± 1.9),(38.4± 0.9) and (60.0± 4.2) g,t=-3.11,-3.97,3.67,-6.52 and-3.72,all P＜0.05].On the twenty eighth day,the score of open field test in the experimental group was significantly higher than that in the control group (36.5 ± 2.9 vs 24.3 ± 3.6,t=7.36,P＜0.01).So was the hanging test (3.6± 1.0 vs 2.0±0.7,t=3.53,P＜0.01).In Cylinder test,the ratio of left/both and right/both forefeet in the experimental group were similar [(49.8± 13.3) ％ vs (41.4±5.9) ％,t=0.86,P＞0.05],but the ratio of left/both forefeet in the control group was higher than right/both [(49.5 ± 11.3) ％ vs (31.2±3.2) ％,t=4.38,P＜0.01].Conclusions HUcMSCs are able to enhance the number of oligodendrocytes while weaken the activity of microglias in the WMD newborn rat model,and to promote the physical development and improve the rat neurobehavior.

Objective To analyze the influential factors of clinical pregnancy rate of the frozen-thawed embryo transplantation. Methods The data of 3 192 FET patients in the reproductive medicine center of our hospital up to May 2014 were analyzed retrospectively. According to ages, reasons of infertility, types of infertility, duration of infertility, drug regimen, the number and the time of embryo transplantation, we divided these patients into six groups for comparing the clinical pregnancy rate. Results The FET clinical pregnancy rate of the under 35 years group was higher than the 35~39 years group and the over 39 years group (33.96%vs. 27.58%and 19.35%; P<0.05, respectively). The duration of infertility in the clinical pregnancy group was significantly shorter than the non-pregnancy group (P<0.05). The clinical pregnancy rate in the group with three embryos transplanted was higher than the group with only two embryos transplanted (41.01% vs. 28.75%; P < 0.05). Among the group with the age of over 40 years, those with three embryos transplanted had a higher clinical pregnancy rate than those with only one embryo transplanted (25.49% vs. 0.00%; P < 0.05). The clinical pregnancy rate of the frozen blastocyst transplantation group was higher than that of the cleavage-stage transplantation group (40.00%vs. 26.27%;P<0.05). Conclusion Age, infertility duration, the number and the time of frozen embryo transplantation may affect the clinical pregnancy rate among the FET patients. An individualized transplantation program based on age may improve the patient′s clinical pregnancy rate.

Objective To establish the HepG2 cell lines which can stably express and replicate hepatitis 13 virus (HBV).Methods One point two X unit length of HBV genome was cloned intn SalⅠsite of the eukaryotic expression vector pREP10 to construct the recombinant plasmid pREP-HBV. Human hepatoblastoma cell HepG2 was transfected with pREP-HBV by Lipofectamine 2000 and seh,cted by bygromycin at the concentration of 250?g/mL.HBsAg and HBeAg were monitored by enzyme linked immunosorbent assay (ELISA)kits.H13V particles presemed in supernatant were ex- amincd by electronic microscopy.DNA isolated from intracellular HBV core particles was analyzed by Southbern blot using HBV-specific probe.Results The recombinant vector pREP HBV containing 1.2?unit length of HBV DNA was constructed successfully.After transfection of pREP-HBV to HepG2 cells and consistently cultured in hygromycin selective medium.5 drug-resistant cell lines, RHBV1-RHBV5.were established,and all of them could stably express HBsAgand HBeAg.South ern blot analysis revealed that HBV could replicate in all cell lines,as confirmed by the presence of replicateintermediatc DNA in intracellular HBV core particles.Clustered 42 nm Dane particles as well as 22-26 nm spherical H13sAg particles in condensed cuhure supernatant were visualized by elec tronic microsopic analysis.Conclusion HepG2 ceil lines in which HBV can replicate and express specific antigens are successfully established.Up to now,the cells have been passaged every three days for 50 times.