Objective: To investigate the bactericidal efficacy and impact on oral mixed biofilm microbial structure of commonly used clinical root canal irrigants under dynamic oxygen conditions, and to provide experimental evidence for clinical root canal irrigant selection. Methods: This study has been reviewed and approved by the Medical Ethics Committee, and written informed consent has been obtained from all of the participants. Two healthy oral volunteers from Beijing Stomatological Hospital, Capital Medical University were selected, and subgingival and supragingival plaque from their mandibular premolars and molars were extracted to construct an oral mixed microbial biofilm model. The plaque was cultivated on hydroxyapatite slices for 1 week (anaerobic conditions for 3 days + aerobic conditions for 4 days) to construct a young oral mixed bacterial biofilm model, and cultivated for 3 weeks (anaerobic conditions for 3 days + aerobic conditions for 18 days) to construct a mature oral mixed bacterial biofilm model. Three root canal irrigating solutions were used: sterile water (control), 2% chlorhexidine (CHX), and 1% sodium hypochlorite (NaOCl). The bacterial biofilms were treated for 1 week and 3 weeks, respectively, and the overall bactericidal rate was assessed using live/dead bacterial staining and laser confocal microscopy. Concurrently, high-throughput 16S rRNA sequencing was performed to analyze the microbial community structure and to evaluate the antibacterial effects of irrigation solution, on common dominant pathogens Results: The proportion of dead bacteria in the biofilm treated with three types of root canal irrigation drugs at 1 week and 3 weeks, from high to low, were as follows: 1% NaOCl >2% CHX >control group (P < 0.001). The bactericidal rate of 1% NaOCl on mature biofilms at 3 weeks was significantly lower than that of light biofilms at 1 year (P < 0.001). High-throughput sequencing revealed minimal effects of 2% CHX and 1% NaOCl on biofilm community structure but demonstrated poor bactericidal activity against dominant root canal pathogens, such as Streptococcus and Fusobacterium. Conclusion Under the initial anaerobic and subsequent aerobic culture conditions, 1% NaOCl exhibits potent bactericidal effects on young bacterial biofilms, but demonstrates limited efficacy against mature biofilms and certain root canal dominant bacteria (Streptococcus and Fusobacterium).

Objective To investigate the prenatal diagnosis and phenotypic assessment strategies for fetal supernumerary marker chromosomes and derivative chromosomes. Methods Five cases of fetal supernumerary marker chromosomes and one case of fetal derivative chromosomes were diagnosed in the First Affiliated Hospital of Sun Yat-Sen University from March 12, 2010 to November 9, 2012 by conventional chromosome banding, fluorescence in situ hybridization (FISH) and spectral karyotyping (SKY). These cases were retrospectively reviewed. Combined with the results of ultrasonography, abnormal phenotypes and pregnancy outcomes were evaluated in these cases. Results All of the five supernumerary marker chromosomes were de novo, in which two were mosaic and the remaining three cases were non-mosaic. Of these five cases, two were type 47, XX+mar and ultrasound indicated abnormal phenotypes. FISH and SKY confirmed that they were derived from chromosome 4 and 22, respectively. The other three cases were marker chromosome with Turner syndrome karyotype (abnormal phenotypes were not found by ultrasound), in which two cases were derived from chromosome Y (by FISH) and one case was identified as ring chromosome X (by FISH and SKY). One de novo derivative chromosome was verified as a product of reciprocal translocation between chromosome 2 and 6 (by FISH and SKY). Induced abortion was performed in all cases between 25 and 32 gestational weeks. Conclusions By combining conventional chromosome banding, FISH and SKY, the origin and content of supernumerary marker chromosomes and derivative chromosomes can be identified. On this basis, clinical phenotype evaluation and genetic counseling may be offered with the ultrasonographic result.

Objective To investigate the clinical value of ultrasound markers in screening fetal trisomy 21.Methods From Jan.2001 to Dec.2011,a retrospective study about sonographic information of 138 fetuses diagnosed as trisomy 21 was taken in the First Affiliated Hospital of Sun Yat-sen University.All fetuses were divided into 3 groups:isolated ultrasound markers,non-isolated ultrasound markers,and isolated structural malformations or other abnormalities.The relationship between trisomy 21 and ultrasound markers as well as structural anomalies or other abnormalities was analyzed.Results Sonographic anomalies were detected in 132 fetuses(95.7％,132/138),including ultrasound markers and structural malformations or other abnormalities.One hundred and twenty cases(87.0％,120/138)had ultrasound markers,38(31.7％,38/120)had one marker and 82(68.3％,82/120)had more than one marker (P ＜ 0.01).Fifty-one fetuses(37.0％,51/138)had isolated ultrasound markers and non-isolated markers were found in 69 fetuses(50.0％,69/138).Only 12 fetuses(8.7％,12/138)had isolated structural malformations or other abnormalities.In 20 fetuses on whom the first-trimester ultrasound screening were performed,all had ultrasound markers,95％(19/20)had thickened nuchal translucency and 55％ (11/20)had nasal bone hypoplasia.The most common ultrasound markers on the second-trimester screening were nasal bone hypoplasia,which accounted for 41.9％(52/124)cases,followed by thickened nuchal fold (25.0％,31/124),short fenurs and humerus(24.2％,30/124),echogenic intracardiac focus(16.1％,20/124),mild ventriculomegaly(15.3％,19/124),hyperechoic bowel(12.9％,16/124),mild renal pyelectasis(12.1％,15/124).Furthermore,thc common structural malformations or other abnormalities were as follows:cardiac defects(33.1％,41/124),digestive system(26.6％,33/124).Condusions Ultrasound markers are valuable for screening fetal trisomy 21.The fetuses of trisomy 21 usually had more than one ultrasound markers or associated with other abnormalities.Combinations of ultrasound markers with the results of serum screening and maternal age are necessary for evaluation.

Electromagnetic blood flowmeter (EBF) and polygraph system were used for measuring the coronary blood flow (CBF), left ventricular systolic pressure (LVSP),mean aortic pressure (MAP ), heart rate respectively in anesthetized dogs. In group 1 (6 dogs ), after opening the chest,the left coronary artery was surrounded by a fitting flow prob of EBF and ploygraph system was connected with dogs. morphine (2mg. kg-1 ),morphine plus naloxone were intravenously injected into dogs respectively. It showed that CBF was increased 56. 8% with morphine, while the LVSP and MAP decreased, HR not changed. The effect mentioned above were partly antagonized by naloxone (0. 4mg/kg). In group 2(3 dogs) using same methods, HR.CBF. LVSP and MAP were decreased with high dose fentanyl (100ug/kg ). The results suggested that in clinic the use of high dose fentanyl should be careful during anesthesia for the patients with cardiopathy. However, the effect of morphine in increasing CBF may be beneficial for the patients with myocardial ischemia.