Root canal biofilm is frequently detected in the canal wall of infected root canal and the root canal with failed root canal therapy. Due to its special structure and diverse composition, root canal biofilm has the ability of the drug tolerance and antiimmunity, which lead to apical periodontitis. This review summarizes the features of the root canal biofilm and latest clinical methods to remove it.

Objective:To establish the methods for the determination of Mg,Al,K,Ca,Cr,Cu,Zn,As,Se,Ag,Cd,Sn,Ba,Pb,Na and Hg in water for injection. Methods:The sixteen metallic elements in water for injection were determined by ICP-MS. The collision cell technology ( CCT) was used to minimize the multiple atomic interference, and the matrix effect and signal drift were compensated by using Li, Sc, Ge, In, Ir and Bi as the internal standards and the samples were directly acidified to detect the metallic elements. Results:The detection limit range of the 16 metallic elements were from 0. 009 to 0. 165 ng·ml-1. The calibration curves showed good linearity (r≥0. 999 0). The recoveries were within the range of 80%-120%(n=6). Conclusion:The method is simple, rapid and accurate. It can be used to determine the contents of metallic elements to reduce the potential exceeding limit risk of toxic metal el-ements in water for injection. The methods also can provide reference for the more strict quality evaluation of water for injection.

Objective To study the expression of TFIIB-related factor 2 (BRF2) in hepatocellular carcinoma(HCC) and to determine its clinical significance.Methods 80 HCC patients who received ‘curative' hepatectomy at the Qilu Hospital were studied.Immunohistochemistry analysis was performed to examine the expression of BRF2 and CD34 (microvessel density) in tumor tissues,matched paraneoplastic tissues,and normal liver tissues.Statistical methods were performed to analyse the relationships of expressions of BRF2 and CD34 with clinicopathologic factors.Results BRF2 protein was expressed at a high rate of 61.3％ in HCC tumor,which was significantly higher than that in normal liver tissues and matched paraneoplastic tissues (31.6％,28.8 ％,respectively,P ＜ 0.05).BRF2 was significantly associated with tumor differentiation,number of nodules,tumor encapsulation,TNM stage,and microvessel density.Prognosis of the high expression BRF2 group was poor.The recurrence and metastasis rates in the high expression group were significantly higher than the low expression group (P ＜ 0.05).The survival rate in the high expression group was significantly lower than the low expression group (P ＜ 0.05).Conclusions The expression of BRF2 increased in HCC tissues,and its expression was closely associated with pathological features and prognosis of patients,indicating that it can be used as a predictor in assessing prognosis of patients with HCC.

Objective To compare the clinical efficacy of minimally invasive removal of intracranial hematomas and medical con-servative treatment for hypertensive cerebral hemorrhage .Methods A total of 75 patients with hypertensive cerebral hemorrhage were collected and randomly divided into two groups according to the treatments :38 patients treated with conservative medicine and 37 patients treated with minimally invasive removal of intracranial hematomas based on standard drug therapy .Neurological impair-ment and recovery of self-care ability of patients in both groups before and after three weeks and six weeks of treatment were scored by National Institute of Health Stroke Scale (NIHSS) .Changes of diffusion tensor imaging before treatment and after two weeks of treatment were evaluated by fractional anisotropy value (FA) .Results There was no significant difference between neurological im-pairments of the patients in two groups before treatment .But the recovery degree of functional impairment and muscle nerve in min-imally traumatic treatment group was more significant than those in the conservative medical treatment group after treatments . There was significant difference between two groups (P< 0 .05) .Conclusion Minimally traumatic of hematomas is an effective method of treating hypertensive intracerebral hemorrhage .

Objective To investigate the expression of PHF8(PHD-finger protein 8) in human hepatocellular carcinoma (HCC) and its clinicopathologic significance.Methods The expression of PHF8 in 60 hepatocellular carcinoma samples as well as their natched paraneoplastic tissues,and 15 normal liver tissues were evaluated by immunohistochemistry.Statistical methods were used to analyse the relationship between the expression of PHF8 and the clinicopathological features of these patients.Results The PHF8-positive expression rate in the HCC samples was 55.0％ and it was significantly higher than that in the paraneoplastic tissues and the normal liver tissucs (16.7％,6.7％,respectively,P＜0.05).The expression of PHF8 was closely related to tumor size,tumor nodular numbers,pathological differentiation and TNM-staging (P＜0.05 for all).The 5-year disease-free survival and overall survival in the PHF8-positive group was significantly lower than that in the negative group (P＜0.05).Conclusions PHF8 was overexpressed in HCC samples,and its expression was closely associated with HCC clinicopathological features and prognosis of the patients.

BACKGROUND:Nanosilver has significant antibacterial properties, and nanohydroxyapatite has good biological activity and mechanical strength, while their mixture cannot only promote bone formation but also have antibacterial properties. OBJECTIVE:To observe the effect of nanosilver and nanohydroxyapatite mixed filing on the osseointegration of immediate implants. METHODS: Nine New Zealand white rabbits were randomly divided into experimental group (n=6) and control group (n=3) after four incisors from the upper and lower jaw were extracted. The mixture of nanosilver and nanohydroxyapatite was filed into the tooth socket in the experimental group, while nanohydroxyapatite was filed into the tooth socket in the control group. Titanium screw was immediately implanted into both groups. The intact maxila and mandibular specimens were harvested at the 4th, 8th, and 12th weeks after operation. Gross observation, X-ray bone density analysis, torque test and histological observation were conducted. RESULTS AND CONCLUSION:The gray value and maximum torque value of regenerated osseous tissue at different time points in experimental group were significantly higher than those in the control group (P < 0.05). Within 12 weeks of implantation, the bone formation rate and maturity of new bone tissue were higher in the experimental group compared with the control group, and no inflammatory cel infiltration occurred. At the 4th week after implantation, there was a large amount of inflammatory cel infiltration, and few inflammatory existed at the 8th week after implantation. These results demonstrate that compared with nanohydroxyapatite alone, the mixture of nanosilver and nanohydroxyapatite shows better antibacterial effect, biocompatibility and osteoinductive ability, which may accelerate osseointegration and promote osteogenesis.

BACKGROUND: Based on a mouse model of tibial implantation, some scholars have found that the CaP-coated implant with recombinant human parathyroid hormone (1-34) (PTH(1-34)) shows strong osteogenesis effect at early stage, but this coating has not been applied in the oral environment.OBJECTIVE: To explore the role of local application of PTH(1-34) on immediate implant osseointegration . METHODS: Nine New Zealand white rabbits were randomly divided into two groups (six in experimental group and three in control group). All of the tooth sockets were filled with heterogeneous freeze-dried bone firstly after four incisors of each rabbit were extracted. In the experimental group, a titanium screw with PTH(1-34) loaded CaP coating was implanted into each tooth socket, while in the control group, a titanium screw with only CaP coating was implanted. The animals were executed respectively at 4, 8, 12 weeks after operation, and the intact maxillary and mandibular specimens were harvested and tested by gross observation, bone density analysis, torque test, histologic al observation, X-ray observation.RESULTS AND CONCLUSION: The gray value and maximum torque value of regenerated osseous tissue at different time points in the experimental group were significantly higher than those in the control group (P < 0.05). Within 4-12 weeks after implantation, regenerated and mature bone tissue appeared earlier in the experimental group than the control group. A large amount of new blood vessels were seen in the experimental group at 8 weeks after implantation, while in the control group, there were only few new blood vessels. To conclude, the local application of PTH(1-34) can promote bone formation, improve the implant-bone bonding strength, and enhance the stability of the implant.

Objective: : To explore the effect of PD-1 gene knockout by CRISPR/Cas9 system on the proliferation and IFN-γ secretion in human T cells. Methods: : The sequence of sgRNA targeting PD-1 was designed. The PD-1-sgRNA and Cas9 mRNA were synthesized by T7 RNApolymerase in vitro, and then the mixture of PD-1-sgRNAand Cas9 mRNAwas delivered into activated T cells by nucleofection. The efficiency of gene knockout was confirmed by sequencing. The phenotypes of T lymphocytes and the expression of PD-1 after gene knockout were analyzed by Flow cytometry. The proliferation of T lymphocytes was calculated by trypan blue counting. The level of IFN-γ secreted by T lymphocytes was detected by ELISA. Results： ：PD-1-sgRNA and Cas9 mRNA were successfully synthesized in vitro and delivered into T cells by nucleofection. Sequencing technology confirmed that the PD-1 gene sequence was edited and the editing efficiency was 58.3%. The expression of PD-1 on T lymphocyte surface was down-regulated successfully by CRISPR/Cas9 system [(9.6±1.85)% vs (16.2±2.05)%, P<0.05]. The knockout of PD-1 gene did not affect the proliferation and phenotype of T lymphocytes(P<0.05); However, compared with the control group, the level of IFN-γ secreted by T lymphocytes in the PD-1sgRNA group was significantly increased (P<0.01). Conclusion: : CRISPR/Cas9 system can successfully ablate PD-1 gene in human T lymphocytes, which could block the negative regulation of PD-1／PD-L1 and further promote the IFN-γ secretion in T cells.

Objective To investigate the expression of Semaphorin3B (SEMA3B) in hepatocellular carcinoma (HCC) and reveal its clinical significance.Methods Immunohistochemistry and Western blotting were performed to examine the expression of SEMA3B protein in 56 hepatocellular carcinoma samples,matched perineoplastic tissues and 14 normal liver samples.Microvessel density (MVD) was determined by counting CD34-positive endothelial cells.Statistical methods were performed to analyse the relationships between the expression of SEMA3B and clinicopathologic factors.Results The rate of the SEMA3B-positive in HCC tissues was 42.9％ and significantly lower than that in normal liver tissues and non-cancerous adjacent liver tissues(78.6％ and 85.7％,respectively)(P＜0.05).MVD in SEMA3B-positive HCC tissus was lower than that in SEMA3B-negative HCC tissus (P＜0.05).The expression of SEMA3B was closely related to tumor nodular number,tumor size,tumor capsulation and CLIP score (P＜0.05 for all).The recurrence and metastasis rate in SEMA3B-positive group was lower than that in the negative group(P＜0.05),and the survival rate in positive group was higher than that in the negative(P＜0.05).Conclusion The expression of SE-MA3B was decreased in HCC tissues,and its expression was closely associated with tumor progression,angiogenesis and prognosis,indicating that it might seve as a predictor of prognosis and a possible novel target of antiangiogenic therapy for patients with HCC.

Objective To investigate the influence of diversification continuing care on quality of life and activities of daily living of epilepsy patients secondary to cerebral hemispheric atrophy.Methods Twenty epilepsy patients with cerebral hemispheric atrophy,admitted to Second Department of Neurosurgery of Hebei Provincial People's Hospital from March 2012 to December 2014 were selected by convenience sampling method,and divided into the intervention group (12 cases) and control group (8 cases),Patients in the control group were given routine guidance discharge,and intervention group were given continuing nursing intervention.The influence of diversification continuing care on quality of life and activities of daily living of epilepsy patients were compared between two groups.Results Twelve months after discharge,QOL in the control group and the intervention group scored 58.8±20.9 and 77.2±14.3,t=2.37,P ＜ 0.05.The ADL scored 49.42±8.14 and 62.72±7.06,t=2.39,P ＜0.05.Conclusions Diversification continuing nursing intervention is helpful to improve quality of life and activities of daily living of epilepsy patients secondary to cerebral hemispheric atrophy.