Using the character of natural aggregation of CHO cells, and an ultrasonic and sedimentation column combined perfusion system to promote cells aggregation and retention into bioreactor,recombinant CHO cell strain MK3-A2 was cultured,which could secrete rhTNK-tPA, by a serum-free perfusion culture system. The culture periods in this two experiments were as long as 77 and 110 days respectively. The cells density reached 2?107 cells /ml. The average volumetric productivity of rhTNK-tPA was 89 mg/L?d, and the highest one was 216mg/L?d.The cells aggregation rate was approximately 90%, and the diameters of most of them were 285～570?m. During the perfusion culture the cells retention rate almost kept in 95% and the viability of cells was more than 85%.Thus, it means that aggregation culture with such perfusion system could be used to scale up produce biopharmaceuticals instead of microcarrier culture system.

【Subjects】 To investigate the clinical application value of myocardial contrast echocardiography （MCE） in selecting CTO-PCI patients. MethodsFrom February 2019 to March 2020， a total of 50 patients with chronic coronary artery occlusion were consecutively selected as the research subjects. MCE and two-dimensional speck-tracking echocardiography were completed before and 12 months after interventional therapy. The primary end point was major adverse cardiovascular events. Patients were divided into groups according to the preoperative myocardial perfusion level of MCE. The improvement of left ventricular function was evaluated by two-dimensional echocardiography and left ventricular global longitudinal strain. ResultsCompared with the abnormal perfusion group， the improvement of GLS in the normal perfusion group was greater （P=0.028）. The wall motion score index （WMSI） of the abnormal perfusion group before PCI was higher than that of the normal perfusion group （P=0.002）. WMSI in the abnormal perfusion group was higher than that in the normal perfusion group one year after PCI （P<0.001）. The left ventricular GLS（P=0.008）.WMSI（P=0.016） and left ventricular end-diastolic volume（P=0.032） in the normal perfusion group were improved compared with those before operation； The postoperative perfusion score of patients with abnormal perfusion was significantly improved （ P=0.032）. ConclusionMCE has clinical application value in optimizing the selection of CTO-PCI patients. CTO patients with different myocardial perfusion types have different benefits after PCI.