In the complications of dental implant treatment, the mechanical complications, such as central screw breakage, are often complex and serious. This article analyzes factors that affect the loosening of the central screw. Understanding relevant risk factors can prompt doctors to take corresponding strategies to reduce the possibility of complications in clinical operations. After encountering broken cases, this paper also gives some ideas and methods of treatment, and finally summarizes clinical suggestions for preventing the central screw fracture.

Objective · To investigate the effects of ox-LDL on the proliferation of rat theca cells and expression of LXR-α and StAR, two genes associated with androgen biosynthesis. Methods · The expression of LXR-α in the ovarian tissue of rats was determined by immunohistochemistry. Primary theca cells were isolated and collected from rat ovary and cultured in vitro. Furthermore, the theca cells were treated with 25, 50, 100, 150, 200, 300 and 400 mg/L ox-LDL, respectively. The variations in LXR-α mRNA were identified using real-time PCR. MTT assay was performed to detect cell viability. The expression of LXR-α and StAR was measured by Western blotting analysis. Results · The effect of ox-LDL on the proliferation of rat theca cells and the levels of LXR-α and StAR in theca cells was in a concentration-dependent manner. Following exposure to various concentration of ox-LDL for 24 h, the proliferation of theca cells was induced by low concentration of ox-LDL (25-150 mg/L), and 100 mg/L ox-LDL showed the most significant inducing effect. Moreover, the cell survival rate was diminished considerably following with ox-LDL concentration increasing, especially lowered by 400 mg/L ox-LDL. The mRNA level of LXR-α was increased with low concentration of ox-LDL (25-150 mg/L) and the impact of ox-LDL on the induced expression of LXR-α mRNA was considerably distinct at the concentration of 150 mg/L. On the other hand, the expression of LXR-α mRNA was reduced with high concentration of ox-LDL, and the impact of 400 mg/L ox-LDLwas substantially distinct. The protein expression levels of LXR-α and StAR were increased with 150 mg/L ox-LDL, but StAR protein level in 150 mg/L ox-LDL group revealed no significant difference when compared with control group. The expression of LXR-α and StAR protein was significantly inhibited with 400 mg/L ox-LDL in the rat theca cells. Conclusion · Low concentrations of ox-LDL can induce the proliferation of theca cells, and promote the expression of StAR and LXR-α. Whereas, high concentrations of ox-LDL can reduce the cell viability and inhibit the expression of StAR and LXR-α.

Molecular medicine and cancer research center in Chongqing Medical University adhered to academic honesty and credit education ,established original laboratory records system , regularly carried out seminar and improved paper submission program thus to reject academic miscon-ducts from the source,guarantee the authenticity of the data and improve the academic moral level of postgraduates.

Objective To ascertain serum inflammatory markers could be modified following treatment of periodontal disease in elderly patients. Methods The probing depth (PD), clinical attachment level (AL), C-reactive protein (CRP), interleukin-6 (IL-6) were determined. And then fifty-two elderly periodontitis patients underwent a standard phase of non-surgical periodontitis treatment (consisting of oral hygiene instructions and subgingival scaling and root planning). After three and six months, PD, AL, CRP and IL-6 were determined again and compared to the baseline. Results Six months after treatment, significant reductions in PD [(5.9±1.1) mm vs. (6.8±1.0) mm, P＜0.05], AL [(1.3±0.9) mm vs.(8.4±1.1) mm, P＜0.05], CRP [(1.5±0.2) mg/L vs. (2.0±0.3) mg/L, P＜0.01] and IL-6 [(1.6±0.5) ng/L vs. (1.9±0.4) ng/L, P＜0.05] were observed. Conclusions Treatment of chronic periodontitis can decrease the levels of serum inflammatory markers in elderly patients.

Objective To investigate the effect of fluorescence in situ hybridization (FISH) in increasing the accuracy and detection rate of chromosome aneuploid from spontaneous abortion specimens.Methods Chromosome 13,21,16 and 22 single sequence probes and centromere probes of 18,X and Y chromosome probes were used to detect 100 cases of spontaneous abortion villi samples.The results were compared with conventional karyotype analysis.Results (1) Karyotype analysis:Among 89 successfully cultured villi samples,51 abnormal karyotypes (57.3％) were found,including 37 cases of autosomal aneuploidies,four sex chromosome aneuploidies,two triploids,one tetraploid,one 68,XX and six chromosome structural aberrations.(2) FISH:The detection rate of abnormal karyotype was 38.0％ (38/100),among which 25 cases were autosomal aneuploidies,five sex chromosome aneuploidies,three triploids,four XX chimeras and one triploid in chromosome 13,16,18 and 21.(3) Comparison of the two methods:Among the 11 samples which failed by conventional method,FISH found two abnormal samples.In specimens of 46,XY,three cases showed mosaicism by FISH.In specimens of 46,XX,two cases showed chromosomal abnormalities by FISH.FISH detected overall 65.5％ (38/58) of the chromosomal abnormalities.Conclusions FISH combined with conventional chromosome analysis could improve the accuracy and detection rate of abnormal karyotypes in spontaneous abortion specimens.

Objective To study the effects of prokaryotic ubiquitin-like protein ( Pup)-proteasome system on the growth of Mycobacterium strains.Methods The genes encoding Pup ( pup gene) and protea-someβsubunit ( prcB gene) were respectively knocked out from Mycobacterium smegmatis ( M.sm) strains by homologous recombination.The growth and viability of the wild-type and mutant strains of M.sm were an-alyzed under normal culture condition and under hypoxia as well as anaerobic conditions.Results The pup and prcB genes were completely and precisely knocked out from M.sm strains and the mutant strains were named △SM-Pup and△SM-prcB, respectively.The△SM-Pup strains grew faster than the wild type ( WT) and△SM-prcB strains.No significantly differences in the growth of M.sm were found between the WT and△SM-prcB strains.Conclusion The Pup-proteasome system was involved in the growth of M.sm, espe-cially the pup gene.There was difference between pup and prcB genes in regulating the growth of M.sm.The functions and influences of Pup-proteasome system still need further investigation.

Objective To construct the eukaryotic expression vector of pprI gene from Deinococcus radiodurans R1 and investigate its radioresistant effects in eukaryotic cells.Methods A recombinant vector pEGFP-c1-pprI was constructed by DNA recombinant technique.The empty vector pEGFP-c1 and the pEGFP-c1-pprI were transferred into human lung epithelial cells Beas-2B by LipofectamineTM 2000,respectively.Then the infected cells were screened in order to develop a cell line with stable expression of pprI gene.Cell survival rate was tested by clone-forming assay.Cell cycle distribution and apoptosis were detected by a flow cytometry.The fluorescence intensity of reactive oxygen species (ROS) was observed by a fluorescent microscope.γ-H2AX foci in the irradiated cell was detected by immunofluorescence.Results The eukaryotic expression plasmid of pprI prokaryotic gene was constructed and PprI fusion protein was expressed in human lung epithelial cells successfully,and the cell line (2BG) with a stable pprI gene expression was established.After irradiation,the cell survival fraction of 2BG cells was significantly higher than Beas-2B cells so that the value of D0 、Dq and N of the survival curve were increased.Moreover,the fluorescence intensity of ROS and the number of γ-H2AX foci in 2BG cells were also lower than those of B eas-2B cells(F =16.73,19.47,6.94,P ＜ 0.05).Between these two cell lines,the apoptosis rate and cell cycle G2 arrest also had significant difference (F =139.73,237.92,P ＜ 0.05).Conclusions The pprI gene from Deinococcus radiodurans RI can be stably expressed in the eukaryotic cells and it allows the transferred cells to have a radioresistant function.

AIM:To observe and compare clinical effects of coaxial 1. 8mm microincision phacoemulsification and 3. 2mm small incision phacoemulsification.
●METHODS:A total of 117 eyes of 85 patients with age-related cataract in our hospital were divided randomly into two groups:43 patients (59 eyes) in the coaxial 1. 8 mm microincision cataract surgery group ( C - MlCS ) , 42 patients (58 eyes) in the coaxial 3. 2 mm traditional small incision cataract surgery group (C-SlCS). A total of 117 eyes were received phacoemulsification with intraocular lens implantation. Uncorrected visual acuity was recorded preoperatively and postoperatively at 1, 7, 30 and 90d. The effective phacoemulsification time and average ultrasound energy were recorded in surgery. Corneal endothelial cell and corneal topography were recorded preoperatively and postoperatively at 90 d.
●RESULTS:Uncorrected visual acuity ( logMAR) was no overall statistical significance difference between C-MlCS group and C-SlCS group (P>0. 05), but was significant statistical difference in different time-point within both groups(P<0. 05). Uncorrected visual acuity in different time-point had nothing to do with corneal wound size in cataract surgery(P>0. 05). On the 1 day after surgery, uncorrected visual acuity was 0. 16±0. 11 in C-MlCS group and 0. 22±0. 18 in C-SlCS group(P<0. 05). AVE was (7. 00± 2.72)% in C-MlCS group and (6. 16±3. 16)% in C-SlCS group (P>0. 05). EPT was (3. 09±1. 61)s in C-MlCS group and (3. 20±1. 92)s in C-SlCS group (P>0. 05). At 90 d after surgery, corneal endothelial cell loss percentage was (5. 81±2. 28)% in C-MlCS group and (5. 69±2. 38)% in C-SlCS group (P>0.05), SlA was (0.35±0.11) Din C-MlCS group and (0. 61±0. 13) D in C-SlCS group (P<0. 05).
● CONCLUSION: Compared with coaxial 3. 2mm traditional small incision cataract surgery, 1. 8mm coaxial microincision cataract surgery can get earlier visual rehabilitation and significantly reduce SlA. The coaxial 1. 8mm microincision cataract surgery is safe, effective and deserves further clinical applications.

AIM: To determine the optimal operation method and reduce operative complications by retrospective analysis of outcomes of different operative manipulation for patients with congenital ectopia lentis ( CEL) .
●METHODS: A retrospective study ranged from Jan. 1, 2010 to Jan. 1, 2015 was conducted and 31 CEL patients (57 eyes) treated with different operations were taken into this study. The postoperative outcome, operation related complications was analyzed in terms of different operative manipulations.
● RESULTS: The most common types of CEL are idiopathic and Marfan - related CEL. All eyes ( 98%) benefited from operation except 1 Marchesani syndrome eye concurrent with optic atrophy induced by glaucoma. A total of 3 eyes ( 5%) were treated by phacoemulsification combined with intraocular lens implantation; 8 eyes ( 14%) were treated by phacoemulsification, capsular tension ring implantation combined with intraocular lens implantation, among these 8 eyes, 1 eye was treated with capsular tension ring implantation combined with suture fixation; 39 eyes ( 68%) were treated by lens excision and anterior vitrectomy through corneal incision combined with intraocular lens implantation with suture fixation, among these 39 eyes, 2 eyes were treated with trabeculectomy , but not combined with intraocular lens implantation; 5 eyes ( 9%) were treated by intracapsular cataract extraction and anterior vitrectomy combined with intraocular lens implantation with suture fixation; 2 eyes ( 4%) were treated by lens excision and vitrectomy through pars plana combined with silicon oil injection.
● CONCLUSION: Almost all patients can obtain satisfactory outcomes through various operative manipulations. Phacoemulsification combined with intraocular lens implantation was the first choice for patients with lens dislocation range less than 90°. Phacoemulsification, capsular tension ring implantation combined with intraocular lens implantation was recommended for 90° - 180°, and lens excision and anterior vitrectomy through corneal incision combined with intraocular lens implantation with suture fixation was more suitable for lens dislocation range more than 180°. The appropriate operative methods for different types of CEL patients is the key to success.

Objective To observe the influence of environment stimulation on learning and memory ability and hippocampal pathology of neonatal rats with hypoxic-ischemic brain damage (HIBD).Methods The models of HIBD SD rats were established by the method of Rice, and were divided randomly into three groups: enriched environment stimulation group (EE), impoverished environment stimulation group (IE), and standard environment stimulation group (SE). The sham-operation rats were served as control group. Different environment stimulation was administrated to the rats since day 1 after HIBD.On the day 28,Morris water maze was used to evaluate the learning and memory ability. HE staining and nissl stain were employed to observe the pathological change and the number of neurons in hippocampus of rats.Results The learning and memory ability of EE group was significantly higher than that of SE group (P0.05), and the ability of SE group was higher than that of IE group ( P0.05). The number of SE group was lower than that of Sham group (P