AIM: To clone and express the metalloproteinase domain of human von Willebrand factor-cleaving protease (vWF-cp). METHODS: The metalloproteinase domain of human vWF-cp, amplified from the plasmid containing the vWF-cp cDNA gene by using polymerase chain reaction, was cloned into pUC18, and its accuracy was verified by sequencing. Then the domain was inserted into the multiclone site of pET28a(+) and included a 6?His Tag at its amino terminal. After induced by IPTG, the recombinant protein was purified by using a Ni-NTA column and confirmed by Western blot. RESULTS: Comparison of the nucleotide sequence of our cloned domain with the GenBank sequence revealed no difference. High-level expression of the recombinant protein was yielded after 5-hour induction, which amounted to 28% of total bacteria protein in inclusion body. Western blot demonstrated that it possessed high specificity. CONCLUSION: The metalloproteinase domain of vWF-cp was high efficiently expressed in Escherichia coli. This might contribute to the further study of the relationship between its structure and function. [

0.05). There was no difference between various historical types neither. But it was found that there was a trend that AgNOR counts would increase as the increase of the historical grade and there was a significant difference (P

Objective    To investigate the reliability and safety of the technique of percutaneous left ventricular transapical access guided by cardiac three dimensional CT angiography (3D-CTA) combined with echocardiography applied in structural heart defects. Methods    The clinical data of 9 patients (7 males and 2 females with a median age of 50 years ranging from 43 to 64 years) with paravalvular leaks closed by percutaneous left ventricular transapical access in West China Hospital, from April 2015 to August 2018, were retrospectively analyzed. We applied preoperative cardiac 3D-CTA to define the puncture site and trace, which was established by combining with real-time guidance of transesophageal echocardiography (TEE/3D-TEE), and an occluder was deployed at the apical access point for hemostasis with real-time guidance of transthoracic echocardiography (TTE). Results    The puncture needles were successfully introduced into the left ventricular cavity at one time in all patients without injury of lung tissue, coronary artery or papillary muscle. There was no occluder displacement or apex bleeding. One patient developed pleural effusion caused by intercostal artery injury. Conclusion    That cardiac 3D-CTA is used to define puncture sites and trace with advantages of simplicity and repeatability. A safe access and secure exit of left ventricle can be achieved by combining with real-time guidance of echocardiography. There are acceptable technology-related complications.

Objective    To explore the mechanism of volume-related mitral regurgitation (MR) from the anatomy of mitral valve. Methods    A total of 32 patients with ventricular septal defect (VSD) combined MR meeting inclusion criteria in West China Hospital from September 2018 to November 2019 were enrolled in this study. The direction relative to the cardiac axis: the deviation of the MR bundle along the left atrial wall was eccentric, otherwises it was central. There were 23 patients of VSD and eccentric MR (EMR, a VSD-EMR group), including 10 males and 13 females aged 21 (10, 56) months, and 9 patients of VSD and central MR (CMR, a VSD-CMR group), including 4 males and 5 females aged 26 (12, 87) months. Besides, 9 healthy children were enrolled in a control group, including 4 males and 5 females aged 49 (15, 72) months. All patients underwent transthoracic echocardiography (TTE) examination at 2 weeks before surgery and 6 months after surgery, respectively, The MR degree, end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), antero-posterior diameter (AP), annulus circumference (AC), commissural diameter (CD) were assessed. Results    Before operation, EDV, ESV, SV, AP, AC and CD in the VSD-EMR and VSD-CMR groups were significantly larger or longer than those in the control group (P<0.05); after operation, EDV, ESV, SV, AP and CD decreased compared with those before operation (P<0.05), but there was no significant difference compared with the control group (P>0.05). Compared with the control group, AC was slightly decreased (P<0.05). There was no significant difference in EF between and within groups before and after operation (P>0.05). The improvement rate of MR was 78.9%(15/19) in the VSD-EMR group and 100.0% (9/9) in the VSD-CMR group. Conclusion    After unloading of volume, the valve structure is back to normal except AC. The improvement rate of MR in the VSD-EMR group is lower than that in the VSD-CMR group, which may indicate that the mechanism of VSD-EMR is more complicated.