Objective To investigate the expression of BRCA1 in chemosensitive and chemoresistant ovarian cancer specimens,so as to provide a novel insight into the epigenetic mechanism involved in BRCA1 transcription. Methods Serous ovarian cancer patients(10 chemosensitive and 10 chemoresistant cancer)were enrolled for the study. BRCA1 levels was analyzed by real?time quantitative PCR. The methylation levels of BRCA1 core promoter(sites 1?4)was determined by pyrosequencing. Regression analysis was used to examine the possible relationship between BRCA1 levels and the methylation levels of sites 1?4 in ovarian cancer specimens. Results Compared to chemosensitive ovarian cancer tissues,BRCA1 levels were increased,but the methylation levels of BRCA1 core promoter(sites 1?4)were decreased in chemoresistant ovarian cancer tissues. How?ever,it is interesting to note that only a significant inverse correlation was observed between BRCA1 levels and the methylated levels of site 4 (r=-0.612,P<0.05). Conclusion Our findings imply that the methylation levels of site 4 in the core promoter of BRCA1 may be widely involved in the regulation of BRCA1 expression and chemosensitivity in ovarian cancer.

Objective:To evaluate the precision of robot-assisted axis pedicle screw placement and to evaluate the factors influencing the accuracy of the placement.Methods:The medical records of 27 consecutive patients who underwent posterior internal fixation of the upper cervical spine for atlantoaxial instability with intraoperative robot-assisted axis pedicle screw placement from January 2017 to December 2020 at Beijing Jishuitan Hospital were retrospectively analyzed. T The cohort comprised 10 males and 17 females, aged 41.3±16.6 years (range 12-75 years), with a body mass index (BMI) of 23.0±2.9 kg/m 2 (range 18.9-30.0 kg/m 2). There were 16 cases of traumatic atlantoaxial instability and 11 cases of atlantoaxial instability caused by deformity. The accuracy of robot-assisted axis pedicle screw placement was evaluated by postoperative CT using Gertzbein-Robbins scale. Factors potentially affecting placement accuracy were initially identified via univariate analysis, with significant factors ( P<0.200) subsequently analyzed through multivariate modeling using generalized estimating equations. Results:A total of 49 axis pedicle screws were placed in 27 patients, with 35 (71.4%) in Gertzbein-Robbins scale grade A, 12 (24.5%) in grade B, 2 (4.1%) in e grade C, and 0 in grades D and E. The clinically acceptable rate (Gertzbein-Robbins grades A and B) was 95.9%. No patient experienced vascular or neurologic injury due to screw displacement. The results of univariate analysis showed no statistical significance for patient factors (age, gender, BMI, preoperative cervical curvature, and causes of atlantoaxial instability); no statistical significance for the surgical factors of tracker position, screw position, screw type, and screw placement approach ( P>0.05), and a statistically significant difference for the difference between the effective width of the axis pedicle and the screw diameter ( t=3.484, P<0.001). The results of multifactorial analysis showed that tracker fixation to the Mayfield frame in robot-assisted axis pedicle screw placement over the axis spinous process resulted in more accurate screw placement [ OR=83.231, 95% CI(3.898, 1776.952), P=0.005]; and the greater the difference between the effective width of the axis pedicle and the diameter of the screw, the greater the accuracy of screw placement [ OR=5.330, 95% CI(1.648, 17.243), P=0.005]. Conclusion:Robot-assisted axis pedicle screw placement is both precise and safe. Securing the tracker to the Mayfield clamp rather than the axis spinous process enhances the accuracy of screw placement. A greater discrepancy between the axis pedicle's effective width and the screw diameter decreases the likelihood of cortical violation. Preoperative planning, including the selection of appropriate screw types and adjusting the trajectory in three dimensions to maximize the difference between the pedicle's effective width and the screw diameter, can mitigate the risk of cortical breach and subsequent vascular and neurological injury.

OBJECTIVE： To establish HPLC fingerprint of Pholidota chinensis and cluster analysis the samples， and to provide reference for quality evaluation of P. chinensis. METHODS： HPLC fingerprints of 16 batches of P. chinensis from Guangxi， Guangdong and Fujian were established according to 2012 edition of Similarity Evaluation System for Chromatographic Fingerprint of TCM [chromatographic column was Agilent SB-aq column with mobile phase consisted of acetonitrile-0.05％ phosphoric acid solution （gradient elution）， at the flow rate of 1.0 mL/min. The detection wavelength of 220 nm， the column temperature was 30 ℃ and the sample volume was 5 μL].The cluster analysis was carried out by using SPSS 22.0 statistical software. RESULTS： Accoding to the established HPLC fingerprint， 11 common peaks were indentified， and the common peak 1 was identified as gastrodin； the similarity of 16 batch of samples was greater than 0.9. 16 batches of medicinal materials could be divided into 2 groups. CONCLUSIONS： The established HPLC fingerprint and cluster analysis can provide reference for the quality control of     P. chinensis.