To prepare the polyclonal antibody against the 3D polymerase of foot and mouth disease virus (FMDV), the 3D polymerase gene of this virus was amplified by PCR and doubly digested with BamH I and Nde I. Then, it were cloned into expression vector pET-30a(+) to obtain the recombinant plasmid pET-3D and this plasmid was transformed to E.coli BL21(DE3) with induction by IPTG.The target protein was identified and purified with SDS+PAGE, and the inclusion bodies were extracted. The purified target protein was used as antigen to immunize New Zealand rabbits to prepare the polyclonal antibody against 3D polymerase of FMDV, which was then characterized by indirect ELISA and Western blotting. As demonstrated by SDS-PAGE, the target protein with a molecular weight at 46 ku was expressed. The polyclonal antibody showed high affinity and obvious specificity and its titer was above 1:8 000. This polyclonal antibody may lay a foundation for the further studies on the biological functions and epitopes of the 3D polymerase of FMDV.

Objective:To evaluate the clinical application of an angle gauge in internal fixation with proximal femoral nail antirotation (PFNA) for femoral intertrochanteric fracture.Methods:A retrospective analysis was carried out in the 54 elderly patients with intertrochanteric fracture of the femur who had been treated with PFNA internal fixation from February 2016 to August 2018 at Department of Orthopedic Trauma, Central Hospital of Shengli Oilfield. In the experimental group of 25 patients whose PFNA internal fixation was assisted by an angle gauge to measure the anteversion angle, there were 9 males and 16 females with an age of 74.4 years ± 4.6 years, and 7 cases of type 31-A1, 11 cases of type 31-A2, and 7 cases of type 31-A3 by the AO classification; in the control group of 29 patients whose PFNA internal fixation was not assisted by an angle gauge, there were 9 males and 20 females with an age of 74.4 years ± 3.9 years, and 9 cases of type 31-A1, 16 cases of type 31-A2, and 4 cases of type 31-A3 by the AO classification. The 2 groups were compared in terms of operation time, corrections of anteversion angle, intraoperative X-ray exposure times and Harris hip scores at the last follow-up.Results:There were no significant differences between the 2 groups in their preoperative general data, indicating they were compatible( P>0.05). Compared with the control group, the experimental group showed significantly shorter operation time (64.0 min ± 6.5 min versus 72.7 min ± 3.9 min), significantly fewer corrections of anteversion angle (2.8±1.2 versus 4.7±1.5) and significantly fewer X-ray exposure times(7.0±1.2 versus 11.6±1.6) (all P<0.05). This cohort was followed up for 6 to 24 months (average, 11 months). By the Harris hip scores at the last follow-up, therewere 22 excellent cases, 2 good cases and one fair case in the experimental group, and 23 excellent cases, 4 good cases and one poor case in the control group, showing an insignificant difference between the 2 groups ( P>0.05). Conclusion:Application of an angle gauge to assist PFNA internal fixation can lead to shorter operation time, fewer corrections of anteversion angle and fewer X-ray exposure times in the treatment of femoral intertrochanteric fracture.