The key factor responsible for the slowness of registration of medical devices in China is clinical trial. The clinical trial in European and U.S. is taken as an example to analyze the problems in clinical trials in China. Some suggestions are proposed to solve the problem.
China ; Clinical Trials as Topic ; Device Approval ; Research Design

Objective:To explore the value of chest low-dose CT (LDCT) in post-discharge follow-up assessments of patients with coronavirus disease 2019 (COVID-19).Methods:The chest CT findings of 58 patients with COVID-19 from March 17 to March 25, 2020 at Remin Hospital of Wuhan University were retrospectively analyzed. Two radiologists independently scored the subjective image quality on a 5-point Likert scale. The signal-to-noise ratio (SNR) and SD air of images and the CT radiation dose parameters were calculated, including the CT volume dose index (CTDI vol), dose length product (DLP), and effective radiation dose ( E). Results:The subjective image quality scores on CT images obtained before and after discharge by readers 1 and 2, were 4.45±0.22, 3.88±0.33 ( P>0.05) and 4.37±0.18, 3.91±0.35 ( P>0.05), respectively. The SNR and SD air in LDCT after discharge were 4.39±0.95 and 7.19±2.41, which were significantly lower than those in routine chest CT before discharge (5.14±1.06, Z=-5.551, P<0.001; 6.48±1.57, Z=-3.217, P<0.001). All of the obtained images were sufficient for diagnosis. The CTDI vol, DLP, and E in LDCT were significantly lower than those in routine CT [(2.41±0.09), (10.53±1.03)mGy, Z=-6.568, P<0.001; (88.03±5.33), (338.74±34.64)mGy·cm, Z=-6.624, P<0.001; and (1.23±0.17), (4.74±0.48)mSv, Z=-5.976, P<0.001]. Conclusions:Patients with COVID-19 can be followed up with low-dose chest CT after discharge.

OBJECTIVE To study the effects of Wenyang huazhuo tongluo formula conta ined serum on the expression and methylation of retinoic acid related nuclear orphan receptor （RORγt），and to explore the mechanism of its regulation of Th 17 cell proliferation in the treatment of scleroderma. METHODS Wistar rats were given 15，30，60 g/（kg·d）Wenyang huazhuo tongluo formula intragastrically to prepare different doses of drug-contained serum ，and peripheral blood of scleroderma patients were collected to sort Th 17 cells. Using blank serum as blank control ，methyltransferase inhibitor decitabine （DCA）as positive control ， Th17 cells were treated with different concentrations of drug-contained serum ，and then the proliferation of Th 17 cells was detected by CCK- 8；mRNA expressions of RORγt and IL-17 were detected by qRT-PCR ，and the protein expression of RORγt was detected by Western blot assay ；the protein expression of IL- 17 in the cell supernatant was detected by ELISA ，and the methylation level of RORγt gene promoter was detected by methylation-specific PCR. The transcriptional activity of RORγt gene promoter was detected by dual-luciferase assay. RESULTS Compared with blank control ，Wenyang huazhuo tongluo formula contained serum and DCA could inhibit the proliferation of Th 17 cells（P＜0.05），reduced the mRNA and protein expressions of RORγt and IL-17，enhanced the methylation level of RORγt gene promoter and attenuated ， the transcription activity of RORγt gene promoter. Except for mRNA expression of Th 17 and the methylation level of RORγt gene promoter in drug-contained serum low-dose group ，there were statistical significance in above indexes of other groups（P＜0.05）. CONCLUSIONS Wenyang huazhuo tongluo formula can promote the methylation lev el of RORγt gene，and inhibit the expression of RORγt and the secretion of IL-17，so as to inhibit the proliferation of Th 17 cells.