BACKGROUND:Someone regards that treatments such as root canal therapy and post-core restoration can increase the fracture probability of teeth. Can fiber reinforced composite post enhance the fracture resistance of the severe wedge-shaped defected premolar? Three-dimensional finite element can simplify complex dental systems into a model analyzed by computer, and conduct biomechanical research through the model analysis. OBJECTIVE:To analyze the stress distribution of sever wedge-shaped defected first premolar which restored by fiber reinforced composite post and composite resin. METHODS:We established the three-dimensional finite element models of severe wedge-shaped defected maxil ary first premolar before and after restoration with fiber reinforced composite post and composite resin. The maximum bite force was designed to 267 N that was applied at 45° angle. Then, we analyzed the distribution of maximum principal stress in finite element models. RESULTS AND CONCLUSION:The maximum principal stress was concentrated in the tip of defected region. After restoration, the distribution of maximum principal stress was similar to that of the normal premolar, and the tensile stress was distributed uniformly in the upper-central part of buccal root. It may be beneficial for improving fracture resistance ability of severe wedge-shaped-defect premolar by restoration with fiber reinforced composite post and composite resin.

Objective To study the effect of human ?-globin matrix attachment region(MAR) on transgene expression in stably transfected CHO cells.Methods Expression vector was constructed,which contained the ?-globin MAR in both sides of Chloramphenicol acetyltransferase(CAT) reporter gene expression cassette in cis,then transfected into CHO cells.The CAT reporter gene expression was analyzed by ELISA method.Results The ?-globin MAR enhanced the CAT gene expression 5.5-fold in stably transformed CHO cells,while the transgene expression variation among individuals of transformants was decreased.Conclusion MAR increase transgene expression in stably transfected CHO cells.

Objective To evaluate the bone healing effect of vascularized tissue-engineered bone induced by endothelial progenitor cells(EPCs)in repair of large segmental radius defects in rabbits.Methods A total of 68 healthy New Zealand white rabbits were enrolled in the study and randomized into three groups,ie,experimental group(EPCs group):EPCs plus bone marrow mesenchymal stem cells (BMSCs)plus decalcified bone matrix(DBM);control group:BMSCs plus DBM;sham control group:pure DBM.Materials mentioned above were implanted into middle radius defects for 15 mm.At 12 and 16 weeks post-operatively,X-ray test,bone mineral density test,histological light microscopic test,osteocalcin immunohistochemical staining test and biomechanical test were carried out.Results Growth and plasticity of callus,speed of medullary cavity recanalization,bone healing speed and biomechanical intensity in the experimental group were all significantly better than those of control group.Conclusions Vascularized tissue-engineered bone induced by EPCs has strong osteegenic ability,can accelerate bone healing and hence is an effective method for repair of large segmental bone defects.

Objective:To compare the clinical effects of discectomy combined with transpedicular dynamic stabilization and transforaminal lumbar interbody fusion (TLIF) in treating single-level lumbar disc herniation.Methods:From November 2012 to November 2015, a total of 96 patients with single-level lumbar disc herniation (disc height decreased more than 1/3, the width of the basilar part of the herniated disc >6 mm, massive disc herniation or Modic type I endplate changes) treated by discectomy combined with Dynesys dynamic stabilization (Dynesys group, n=48) or TLIF (fusion group, n=48) were enrolled. Clinical assessments included operation duration, intraoperative blood loss, MacNab score, visual analogue scale (VAS), Oswestry disability index (ODI) and rate of complications. Radiographs were evaluated for lumbar mobility, intervertebral height, etc. Results:A total of 86 patients were included in the final analysis (44 in Dynesys group and 42 in fusion group) and were evaluated after 5 years follow-up. The operation duration of Dynesys group (159.61±37.29 min) was less than that of the fusion group (177.42±39.90 min) significantly ( t=2.140, P=0.035). Intraoperative blood loss in Dynesys group (151.78±50.88 ml) was less than that in fusion group (197.74±76.55 ml) with significant difference ( t=3.293, P=0.001). At 5 years follow-up, there were 2 cases with screw loosening and 5 cases with adjacent segmental degeneration in Dynesys group without symptom. In fusion group, there were 12 cases with adjacent segmental degeneration and two of them with symptom. There were significant differences in the incidence of adjacent segment degeneration between the two groups ( χ2=4.012, P=0.045). According to the MacNab criteria, excellent or good cases accounted for 95% in Dynesys group and 93% in fusion group without significant differences ( Z=0.425, P=0.671). VAS back, VAS leg and ODI scores were improved significantly in both groups after 2 years and 5 years ( P<0.05). However, there were no significant differences between the two groups ( P<0.05). The activity of the surgical segment was 4.59°±0.48° in Dynesys group and 1.00°±0.42° in fusion group at 5 years after surgery. The height of intervertebral space in Dynesys group decreased from 11.19±2.07 mm before surgery to 9.98±2.02 mm at 2 years after surgery and to 9.86±1.64 mm at 5 years after surgery ( F=6.462, P=0.002). However, there was no statistically significant difference between the 2 and 5 years follow-up ( q=0.415, P>0.05). At 5 years after surgery, the activity of the first proximal segment in the two groups was 9.74°±3.29° and 11.69°±3.89°, respectively ( t=2.514, P=0.014). Conclusion:Both discectomy combined with dynamic stabilization and TLIF can achieve satisfied clinical effects in treating single-level lumbar disc herniation. Dynamic stabilization preserves the intervertebral activity of surgical segments and results in a lower incidence of adjacent segment degeneration compared with that in fusion surgery. Furthermore, discectomy combined with dynamic stabilization is a less invasive intervention with shorter operation duration and less blood loss compared with TLIF.

Objective:To study the clinical characteristics of different types of neonatal sepsis.Methods:From January 2012 to December 2019, neonates with confirmed sepsis from 5 neonatal centers of central-south China were reviewed. The neonates were assigned into early-onset sepsis (EOS) and late-onset sepsis (LOS) group, and the latter was further subgrouped into hospital-acquired LOS (hLOS) group and community-acquired LOS (cLOS) group. The etiological and clinical characteristics were analyzed. SPSS 26.0 was used for statistical analysis.Results:A total of 580 neonates were enrolled, including 286 (49.3%) in the EOS group and 294 (50.7%) in the LOS group. In LOS group, 147 were in hLOS group and 147 were in cLOS group. The gestational age and birth weight of hLOS group were significantly lower than the other two groups [(32.7±3.6) weeks vs. (37.1±3.7) weeks and (37.7±3.0) weeks, (1 810±717) g vs. (2 837±865) g and (3 024±710) g] ( P<0.05). The common pathogens in EOS and cLOS groups were coagulase-negative staphylococci and Escherichia coli, while Klebsiella pneumoniae was common in hLOS group. Carbapenems usage in the hLOS group was significantly higher than the other two groups [62.6% vs. 28.7% and 16.2%] ( P<0.05). Antibiotics duration in the hLOS group was longer than the other two groups [19 (14, 27) d vs. 15 (12, 20) d and 14 (12, 19) d] ( P<0.05). Conclusions:The clinical characteristics of neonatal sepsis vary among different types of infections, and it is necessary to establish appropriate prevention, control, diagnosis and treatment protocols.

Objective To investigate the feasibility and effectiveness of focused ultrasound on the acne of rabbit ear.Methods Eighteen male rabbits were randomly divided into blank control group,model control group and ultrasound irradiation group.Acne rabbit ear model was established by Kligman's method in model control group and ultrasound irradiation group.Then,continuous ultrasonic irradiation was given in ultrasound irradiation group.Pathological changes were observed at the time of before and after ultrasound irradiation and 14 days after ultrasound irradiation.Results After modeling,hair follicle expansion,hyperkeratosis,acupoint hypertrophy were observed in blank control group.Compared with blank control group,the thickness of horn layer,the sebaceous gland diameter and other index in model controlgroup were statistically significant (P＜0.01);After irradiation,there were hyperemia and edema in epidermis,angiotelectasis and inflammatory infiltrating,but coagulative necrosis in slice was not observed,14 days later,hair follicle mild expansion,mild keratosis,spiny thinning were observed in ultrasound irradiation group,when compared with model control group,the thickness of horn layer,sebaceous gland diameter and other index were decreased in ultrasound irradiation group,and the differences were statistically significant(P＜0.01).Conclusion The ultrasonic focusing treatment on rabbit ear acne is feasible and effective.