BACKGROUND:Streptococcus mutans is an important pathogen of dental caries,and timely detection of its levels is of great significance for early detection and treatment of dental caries. OBJECTIVE:To evaluate the effect of loop-mediated isothermal amplification(FTA-LAMP)direct extraction of Streptococcus mutans DNA. METHODS:(1)Bacterial suspensions containing ATCC standard strains(Streptococcus mutans)were prepared and inoculated into the brain-heart leachate medium.After mixed thoroughly,the mixture was then diluted in a 10-fold gradient into seven concentrations(4.2×107,4.2×106,4.2×105,4.2×104,4.2×103,4.2×102,4.2×10 CFU/mL),two parallel controls were made for each dilution level,and sterile water was used as a blank control.(2)The DNA of Streptococcus mutans was extracted using FTA Elute card,boiling method,kit extraction and lysate extraction methods separately and then amplified using LAMP technology was amplified.A specificity test was also performed to compare the differences between the four DNA extraction methods.RESULTS AND CONCLUSION:The DNA extracted by all four methods met the requirements for LAMP amplification.Specificity test results showed that only Streptococcus mutans could specifically amplify the target gene.The detection limit value of the DNA concentration was 4.2×103 CFU/mL for the lysate method,4.2×104 CFU/mL for the FTA Elute card extraction method,4.2×106 CFU/mL for the kit extraction method,and 4.2×107 CFU/mL for the boiling method.In the other aspects of the four extraction methods,the kit extraction method had the highest experimental cost,number of steps and time;the other three methods had the same number of steps,with the FTA Elute card method requiring the least amount of instruments,the boiling method having the lowest single cost,and the lysate extraction method taking the least amount of time.Only a small amount of bacteria were needed for successful extraction using both the FTA Elute card and lysate extraction methods.Compared with the FTA Elute card method,the lysate extraction method was superior in terms of time,but it had a high single cost and required more equipment.To conclude,the FTA-LAMP technology established in this study has the advantages of ease of operation,high specificity,high sensitivity,and visualization,which is expected to be a new way for efficient extraction and detection of Streptococcus mutans.

Children with pediatric tumors have better prognosis and longer survival than adults, suggesting that attention should be paid to the long-term complications induced by radiotherapy. In this article, the data from more than 40 clinical studies of pediatric tumor radiotherapy published in the recent decade were retrospectively analyzed. Long-term complications of nervous system, cardio-cerebrovascular system, respiratory system, endocrine system, urinary system, reproductive system, skeletal development, long-term secondary tumors were considered and the corresponding radiation dose-volume parameters were summarized, aiming to guide radiation oncology physicians and physicists to optimize radiotherapy plans for children with pediatric tumors.

Objective: To discuss the feasibility and effectiveness of using micro-CT in bone-implant contact (BIC) evaluation in dogs, and to provide reference for clinical and scientific research. Methods: Bilateral mandibular second premolar and first molar of six male Beagle dogs were extracted. After 3 months′ healing, eight implants were placed in bilateral mandible of each dog, four on each side. Dogs were sacrificed at 2 weeks, 4 weeks and 8 weeks after implant placement, two on each time point. Samples were scanned with micro-CT and digitally reconstructed. Bone-implant interface was analyzed at different analysis regions (25, 50 and 100 μm from implants′ surface), different detection range models were obtained (each time point consists 48 models), and BIC was evaluated, and the results were counted as micro-CT₂₅, micro-CT₅₀, and micro-CT₁₀₀ groups. Then undecalcified slides were made (three slides for each sample) and stained with toluidine blue for observation and analysis of BIC using an optical microscope, and the results were counted as optical microscope groups. The advantages and disadvantages, evaluation efficiency and BIC of different methods were analyzed. Results: To evaluate BIC of single sample, it took about 90 minutes by micro-CT, which was much lower than the time of 14 days by optical microscope. The success rates of modeling of micro-CT₂₅, micro-CT₅₀, and micro-CT₁₀₀ groups all were 100.0% (48/48), and total success rate of micro-CT group was 100.0% (144/144). For optical microscope groups, the success rates of making slides 2, 4, 8 weeks were 89.6% (43/48), 93.8% (45/48) and 93.8% (45/48), respectively, and total success rates of optical microscope group was 92.4% (133/144). At 2, 4,8 weeks after implantation, BIC in micro-CT₂₅ group was significantly smaller than that in optical microscope group at the same time point (P<0.05). However, at 2, 4,8 weeks after implantation, BIC of the micro-CT₅₀ and micro-CT₁₀₀ groups showed no significant difference with optical microscope groups at the same time point (P>0.05). A significant correlation (P<0.001, each) was seen between slides and micro-CT (25, 50, 100 μm groups) concerning BIC (r=0.680, r=0.892, r=0.713), and error bias was -19.4%, -0.9%, 3.0%, respectively. The probability within the 95% limits of agreement were 97.9%. Conclusions Micro-CT is a faster, simpler and more efficient way to analyze BIC at the implant-bone interface than optical microscope observation. BIC analysis by selecting 50 μm from implants′ surface as analysis region using micro-CT is in consistent with that using the optical microscope.

Objective: To evaluate the effects of surgical navigation technique in the reconstruction of traumatic orbital wall defect.Methods: 20 patients underwent the operation with the aid of navigation for repairing traumatic orbital wall defect as the test group. 20 patients were treated without navigation as the control group. Treatment outcome was evaluated by correction of exophthalmos, orbital volumes and patient's self-satisfaction. Results: The mean difference of eyeball protrusion between the reconstructed and the unaffected orbit cavity in the navigation group and control group was (0. 81 ± 0. 35) mm and (1. 65 ± 0. 37) mm (P ＜ 0. 05), that of the orbital volume (0. 68 ± 0. 29) ml and (0. 98 ± 0. 22) ml (P ＜ 0. 05), respectively. The patient's satisfaction value of the navigation group was higher than in the control group (P ＜ 0. 05) . The operation duration in the navigation group was less than in the control group (P ＜0. 05) . Conclusion: Surgical navigation can improve the accuracy and the effects of operation for orbital defect reconstruction.

Objective To evaluate the changes in the expression of hippocampal long non-coding RNAs ( lncRNAs) and bioinformatics analysis in mice with perioperative neurocognitive disorders ( PND) . Methods Thirty clean-grade male C57BL∕6 mice, aged 12-14 weeks, weighing 25-30 g, were divided into 2 groups (n=15 each) according to the random number table method: control group (group C) and PND group. The model of PND was established by performing open tibial fracture with intramedullary fixa-tion under isoflurane anesthesia in anesthetized mice. The Morris water maze test, open field test and fear conditioning test were performed at 1, 3 and 7 days postoperatively. The animals were sacrificed after the end of behavioral testing on 3 days after operation, the hippocampus was obtained, the high-throughput gene sequencing was performed to identify the differentially expressed lncRNAs, and Gene Ontology func-tional analysis and Kyoto Encyclopedia of Genes and Genomes signaling pathway analysis were used to ana-lyze the results. Results Compared with group C, the escape latency was significantly prolonged, and the percentage of time spend in the target quadrant and percentage of freezing time in the fear conditioning test were decreased at different time points after operation in group PND ( P<0. 05) . A total of 121 differential-ly expressed lncRNAs were identified, of which 69 were up-regulated and 52 were down-regulated. The Gene Ontology functional analysis showed that there were differences in various biological processes, such as synaptic transmission, cholinergic neurotransmitters, or adiponectin secretion and regulation. The KEGG signaling pathway analysis showed that there were also differences in cholinergic synapses, MAPK signaling pathway, glucagon signaling pathway, TNF signaling pathway, NOD-like receptors, Toll-like re-ceptors, chemokine signaling pathway and etc. Conclusion There are 121 differentially expressed lncR-NAs in the hippocampus of PND mice, and lncRNAs- and the target gene-related inflammatory responses, synaptic transmission, energy metabolism and etc. may be related to the pathogenesis of PND.

Objective: To establish and verify the validity of a finite element(FE) model of fragment injury in swine mandibular composite tissue. Methods: Swine facial composite tissue digital information was obtained by 3D CT,the 3D model and the cylinder fragment with the diameter and height of 5. 5 mm were reconstructed and designed in mimics15. 0. The right mandibular angle region was impacted by the fragment with velocities in finite element analysis software. A two stage light gas gun was used to launch the same shape 30CrMnSi alloy fragment with the speed of 831,1 120 and 1 536 m/s respectively to impact swine mandibular angle area. The actual damage area and acceleration at jaw were measured and compared with the digital simulation results. Results: Compared with the data of digital simulation the fragment with the speed of 831,1 120 and 1 536 m/s resulted in the larger mandibular damage area of entry in the in vivo experiment by 13. 4％,23. 6％ and 22. 3％; that of exit by 18. 7％,23. 0％ and 26. 5％; the smallar accelaration peak by 16. 7％,15. 3％ and 14. 6％,respectively. Conclusion: A digital model of the swine mandible composite tissue fragment injury model is established. The simulation results of the FE model are consistent similar to those of the in vivo test data.

Objective:To summarize the clinical features of clear cell sarcoma of the kidney (CCSK) in children and to evaluate the effica-cy and safety of the WT-2009 chemotherapy protocol. Methods:Clinical data of children with CCSK recorded between January 2009 and December 2014 were retrospectively analyzed. Follow-ups were conducted to monitor the postoperative conditions of the pa-tients. Results:Nine cases of CCSK were recruited, and another three cases were excluded for the analysis because of incomplete clini-cal data. All patients achieved complete remission when the treatment was finished. The estimated 3-year overall survival rate was 100％, and the estimated 3-year event-free survival rate was 83.3％. No report is available on the significant side effects associated with this treatment. Conclusion:CCSK is rare in children and is easily misdiagnosed. The chemotherapy based on the WT-2009 proto-col can produce a favorable prognosis and a high tolerance for patients with CCSK. However, the treatment for high-risk patient needs to be further explored, and follow-ups must be intensified.

Objective To evaluate the effects of exogenous insulin like growth factor 1(IGF-1) on postoperative cognitive function in aged rats. Methods One hundred and twenty pathogen-free healthy male Sprague-Dawley rats, aged 18-20 months, weighing 500-600 g, were divided into 4 groups(n=30)using a random number table: control group(group C), sham operation group(group S), opera-tion group(group O)and exogenous IGF-1 group(group I). Splenectomy was performed, IGF-1 50 μg∕kg was subcutaneously injected at the same time point every day for 7 consecutive day starting from the end of surgery on the day of surgery in group I, and splenectomy was performed, and the equal volume of normal saline was given instead in group O. Morris water maze test was performed on 1, 3 and 7 days after surgery, and the escape latency and swimming distance were recorded. The rats were sacrificed after the end of Morris water maze test, and hippocampi were isolated for determination of the expression of amyloid-β(Aβ), amyloid precusor protein(APP)and β-secretase 1(BACE-1)using immunohistochemistry and Western blot methods. Results Compared with group C, the escape latency and swimming distance were significantly prolonged at 1, 3 and 7 days after surgery, and the expression of Aβ, BACE-1 and APP was up-regulated in O and I groups(P<005), and no significant change was found in the parameters mentioned above in group S(P>005). Compared with group O, the escape latency and swimming dis-tance were significantly shortened at 1, 3 and 7 days after surgery, and the expression of Aβ, BACE-1 and APP was down-regulated in group I(P<005). Conclusion Exogenous IGF-1 can improve postoperative cognitive function in aged rats.

Objective To investigate prevalence and epidemiologic features of Saffold virus (SAFV) in hospitalized children with acute respiratory infection or digestive tract infection Tianjin area. Methods Nasopharyngeal aspirates from children with acute respiratory infection and fecal samples from children with digestive tract infection in Tianjin Children ’s Hospital were collected from January 2013 to December 2013. Viral nucleic acid was extracted, and SAFV infection was determined by using real-time quantitative PCR. Positive PCR products were sequenced. The sequencing results were aligned with known gene sequences of SAFV sequences in GenBank. The positive viral infection rate of nasopharyngeal aspirates and fecal samples, viral positive constituent ratio and positive detection rate in different age groups, seasonal distribution of SAFV infection were calculated. Other common respiratory tract or digestive tract viruses were also detected. Results Fourty-three (11.9%) nasopharyngeal aspirates from children with acute respiratory infection tested positive for SAFV. There was no significant difference between male and female infected children (aged between 6 d and 12 years old). The 79%(34/43) of the patients with SAFV infection aged under 1 year old. The infection most occurred in summer and winter. The 63 (16.4%) fecal samples from children with digestive tract infection tested positive for SAFV. There was significant difference between male and female infected children (aged between 5 h and 11 years old). SAFV infection was found to be year round. There was no significant difference in different age groups of nasopharyngeal aspirates and fecal samples. The mixed infection rate with SAFV and other respiratory tract or digestive tract viruses were 7.0%(3/43)and 12.7%(8/63), respectively. Conclusion Infection of SAFV had occurred in children with acute respiratory infection or digestive tract infection in Tianjin. SAFV has high detection rate in these children and is more common in children
aged under 1 year old. The data suggest that some of acute respiratory infection or digestive tract infections in pediatric patients are related to SAFV. The Clinical doctors should pay attention to them .

Objective To investigate the effect of vascular inner diameter and artery flow velocity on the flow of internal arteriovenous fistula. Methods Sixty-two patients received the operation of internal fistula were enrolled. According to the inner diameter (Group A: d ≤ 1.5 mm, Group B: 1.5 mm < d ≤ 2.0 mm, Group C: 2.0 mm < d ≤ 3.0 mm, Group D: d > 3.0 mm), the patients were divided into four groups in terms of artery flow velocity (Group a: v ≤ 20 cm/s, Group b:20 cm/s < v≤50 cm/s, Group c:50 cm/s < v ≤ 100 cm/s, Group d:v > 100 cm/s), the differences of fistula and dialysis flow for two months were analyzed among various groups. Results Compared with Group B/b, patients in Group A/a had higher risk of operation failure, with lowered inner fistula flow and dialysis flow. In terms of inner venous diameter , there were significant differences between Group B and C. Conclusions It is not recommended to carry out the inner vascular fistula operation. Followed with the thickening and increasing of inner artery diameter and artery flow , the inner fistula flow and the dialysis flow increase. The inner venous diameter has no significant impact on the inner fistula flow.