Objective:To compare the marginal fit changes between after-and before-veneering of the copings using three kinds of materials:gold alloy,cp titanium and Ni-Cr alloy,so as to determine whether the fit changes was influenced with the veneer and their clinical significance.Methods:24 maxillary incisor acrylic resin PFM abutments fabricated by machine with the consolidated standard were divided into three groups,each abutment was waxed-up,invested,and casted with three kinds of materials:gold alloy,cp titanium and Ni-Cr alloy.For all groups,the copings were repositioned on their respective abutments,the marginal fit values of four points of each coping were measured.Furthermore,after three groups of copings were veneered with recommended porcelain,marginal fit values of same point of each abutment were remeasured.SAS software was used to carry out statistical analysis.Results:One way analysis of variance of marginal fit values revealed significant differences between before and after veneering in three groups,and the marginal fit value enhanced after veneered.Among three groups,cp titanium group had a significant difference when compared with other two groups(P

Neoadjuvant chemotherapy evaluation methods are becoming the focus of osteosarcoma chemotherapy research in recent years.This paper updates the evaluation methods of osteosarcoma neoadjuvant chemotherapy in such aspects as pathological histology,imaging studies,and the examination of molecular levels.

Objective To investigate the techniques,safety,and efficacy of intraoperative holmium laser lithotripsy under cholangioscopic visualization for refractory intrahepatic stones. Methods A total of 38 patients with refractory hepatolithiasis underwent cholangioscopic holmium laser lithotripsy.The laser setting was: the wavelength of 2.1 ?m,the maximum mean output power of 100 W,the pulse peak power of up to 6 kW,and the laser fiber of 400 ?m in diameter.Results The stones were entirely removed on one session in all the 38 patients.The lithotripsy time was 3~5 min,the times of fragmentation was 3~8,and a total of 65 stones were fragmented.No bile duct injuries or biliary leakage happened.Cholangiography and B-ultrasonography at 2 postoperative months found no residual stones.Follow-up for 6 months found no recurrence.Conclusions Application of holmium laser lithotripsy under cholangioscopic visualization for the management of refractory intrahepatic stones is safe and effective.

In the present work, Monte Carlo simulations were employed to study the characteristics of the dose distribution of high energy electron beam in the presence of uniform transverse magnetic field. The simulations carried out the transport processes of the 30 MeV electron beam in the homogeneous water phantom with different magnetic field. It was found that the dose distribution of the 30 MeV electron beam had changed significantly because of the magnetic field. The result showed that the range of the electron beam was decreased obviously and it formed a very high dose peak at the end of the range, and the ratio of maximum dose to the dose of the surface was greatly increased. The results of this study demonstrated that we could change the depth dose distribution of electron beam which is analogous to the heavy ion by modulating the energy of the electron and magnetic field. It means that using magnetic fields in conjunction with electron radiation therapy has great application prospect, but it also has brought new challenges for the research of dose algorithm.
Algorithms ; Electrons ; Humans ; Magnetic Fields ; Monte Carlo Method ; Phantoms, Imaging ; Radiation Dosage

Aim To study the effect of Astragalus injection on tumor growth inhibition of human nasopharyngeal carcinoma cell strain CNE2 xenograft in BALB/c nude mice,and explore the possible mechanisms.Methods CNE2 cells were injected subcutaneously into nude mice to establish model of transplanted tumor.Twenty one model nude mice were divided randomly into three groups treated with intraperitoneal injection,viz the model group given normal saline 10 ?l?(g?d)~-1,the positive control group given Cisplatin 30 mg?m~-2 every fourteen days and given normal saline sodium 10 ?l?(g?d)~-1 in other days,and the treatment group given Astragalus injection 10.40 mg?(g?d)~-1.The above administrations for groups lasted 4 weeks.The inhibitory effect of Astragalus injection on the growth of tumors in nude mice was observed,and the inhibitory rate and the relative tumor proliferation rate were calculated.The expression levels of p53 mRNA in tumor tissues were determined by FQ-PCR.Results After four weeks′treatment,the volumes of tumors in nude mice from the model group,the Cisplatin group,the Astragalus injection group were(1.51?0.25)cm~3,(0.91?0.35)cm~3 and(1.04?0.51)cm~3 respectively.Compared with the model group,the tumor volumes in the Cisplatin group and in the Astragalus injection group were smaller(P0.05).Conclusions The results suggest that Astragalus injection shows inhibitory effect on the growth of human nasopharyngeal carcinoma cell strain CNE2 xenograft in BALB/c nude mice,while it can not be claimed that Astragalus injection may affect the expression level of p53 mRNA in transplanted tumor tissue.

Objective To investigate the efficacy of frontoparietal drill versus parietal drill in the burring hole and drainage for chronic subdural hematoma(CSDH),and provide an evidence for clinical application.Methods A total of 82 patients with CSDH from January 2013 to January 2016 in our hospital were randomly divided into observation group and control group.The observation group chose frontoparietal drill which located at the front 1/4 point at the axial view with the thickest hematoma.Control group chose parietal drill which nearby the parietal tuberodties at the axial view with the thickest hematoma.The postoperative residual hematoma volume,intracranial gas volume,recurrence rate,neurologic function and mental state between two groups were compared.Results The postoperative residual hematoma volume,intracranial gas volume,the recurrence rate and CSS were lower compared with the control group,the differences were significant(P<0.05).The MMSE score of observation group were higher that of the control group,the difference was significant(P<0.05).Conclusion The frontoparietal drill has a better effect to remove the hematoma and promotes neural functional recovery.

Objective To evaluate the clinical effects and adverse reaction of raltitrexed combined with radiation for esophageal carcinoma in elderly patients.Methods Sixty patients were randomly divided into two groups by the envelope method, 30 patients in experimental group received raltitrexed combined with radiotherapy and 30 patients in control group received radiotherapy only.Patients in both groups received conventional radiotherapy with a total dose of 56-60 Gy/28-30 F.In experimental group, raltitrexed 2.6 mg/m2 was administered concurrently with the radiotherapy on d1 and d22.Two cycles of concurrent chemotherapy were administered during radiotherapy.The short-term effects, survival times and adverse reactions of the two groups were compared.Results The total effective rates of experimental group and control group were 93.3% and 73.3%, respectively, and there was statistically significant difference between the two groups (χ2=4.320, P=0.038).The median survival times of experimental group and control group was 24.0 months and 12.0 months, respectively, and there was statistically significant difference by Log-rank test (χ2=6.048, P=0.014).The major adverse reactions of grade 3-4 in experimental group and control group were radiation-induced esophagitis (10.0% vs.3.3%;χ2=0.268, P=0.605), leukopenia (13.3% vs.10.0%;χ2=0.000, P=1.000), thrombocytopenia (3.3% vs.0;P=1.000), nausea and vomiting (6.7% vs.0;χ2=0.517, P=0.472), and the differences were not statistically significant.Conclusion Raltitrexed combined with radiotherapy can enhance the short-term effect and prolong the survival time for the elderly esophageal carcinoma patients, and the adverse reactions are mild.It is worthy of further clinical study.

OBJECTIVE To discuss the preoperative locating diagnosis and transnasal endoscopic surgery for cerebrospinal fluid rhinorrhea in sella turcica region.METHODS All of the 22 patients with cerebrospinal fluid rhinorrhea had been located the position of leakage by means of high resolution computed tomography(HRCT),magnetic resonance imaging(MRI)and/or computed tomography cisternography(CTC)techniques,and then the skull base defects were repaired with fascia via transnasal endoscopic surgery.All the patients were followed up for 6 to 51 months.RESULTS Nineteen cases were successfully repaired by operation once and another patient was cured through reoperation.Two cases refused reoperation after failure of the operation and lost follow-up.No complications such as intra-cranial infection and hemorrhage were found during the perioperative period and follow-up.The main failure causes of operation were the necrosis of the repairing fascia,missing the real leakage,and the recurrence of malignant tumor.CONCLUSION It is a key step to locate leakage accurately before operation by means of CT and MRI.Transnasal endoscopic technique is the optimal choice for management of cerebrospinal fluid rhinorrhea in sella turcica region.

The hybrid pencil beam model (HPBM) is an effective algorithm for calculating electron dose distribution in radiotherapy. The mean energy distribution of incident electron beam in phantom is one of the factors that affect the calculation accuracy of HPBM, especially in field edge areas near the end of the electron range. A new fitted formula based on Monte Carlo (MC) simulation data for electron beams with energy range of 6-20 MeV in the homogeneous water phantom is proposed in this paper. The precision of the fitted formula within the scope of the energy was evaluated by comparing the electron dose distribution of ECWG measured data with that obtained from HPBM which took the mean electron energy that calculated by the fitted formula and the existed empirical formula, respectively. The results showed that the accuracy of dose distribution that obtained by the mean electron energy calculated with the fitted formula increased about 1%.
Algorithms ; Electrons ; Humans ; Monte Carlo Method ; Phantoms, Imaging ; Radiotherapy Planning, Computer-Assisted ; Water