The aim of this study is to establish an HPLC method for simultaneous determinations of mifepristone and its metabolites, mono-demethylated mifepristone, di-demethylated mifepristone and C-hydroxylated mifepristone in plasma and to evaluate the pharmacokinetic characteristics of mifepristone tablet. Twenty healthy female Chinese subjects were recruited and a series of blood samples were collected before and after 0.25, 0.5, 1.0, 1.5, 2.0, 4.0, 8.0, 12.0, 24.0, 48.0, 72.0 and 96.0 hours administration by a single oral dose of 75 mg mifepristone tablet. Mifepristone and its three metabolites were extracted from plasma using ethyl acetate and determined by high performance liquid chromatography. The main pharmacokinetic parameters of mifepristone and its metabolites, including Cmax, tmax, MRT, t(1/2), V, CL, AUC(0-96 h) and AUC(0-infinity), were calculated by Drug and Statistical Software Version 2.0. The simple, accurate and stable method allows the sensitive determinations ofmifepristone and its metabolites in human plasma up to 4 days after oral administration of 75 mg mifepristone tablet and the clinical applications of their pharmacokinetic studies.

Objective:Based on the specific cleavage and non-specific "trans-cleavage" activities of the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein(CRISPR/Cas13), we established a visually amplification-free rapid detection technique of 2019-nCoV nucleic acid. This technique is easily processed with a low detection limit and good specificity.Methods:According to the 2019-nCoV gene sequence, specific CRISPR RNAs were screened and designed by bioinformatics analysis, and then synthesized as universal signal-strained RNA transcription targets in vitro to establish and optimize the reaction system. Moreover, the 2019-nCoV pseudoviral nucleic acid was used as a standard substance to evaluate the detection limit. A total of 65 positive samples were collected from various 2019-nCoV variants, while 48 negative samples included other clinically common respiratory pathogens, such as influenza A virus, influenza B virus, human parainfluenza virus, Klebsiella pneumonia, etc. All samples were tested by quantitative PCR (qPCR), digital PCR, and the method established in this study. The sensitivity and specificity of the newly established method were analyzed and evaluated. Results:With the newly established technique, the detection time for 2019-nCoV nucleic acid could be minimized to 6 minutes. In addition, the detection limit was 14 copies/μl when assisted by the displaying instrument, whereas it increased to 28 copies/μl with the naked eye. This technique had a sensitivity and specificity of 98.5% (66/67) and 100% (46/46) respectively, showing no statistically significant difference compared to the gold standard qPCR( P=1). Conclusions:This study has successfully established a CRISPR/Cas13a-based visually rapid detection technique for 2019-nCoV nucleic acid. This technique offers the advantages of a simple process, convenient operation, low environmental operating requirements, a detection limit close to qPCR, and a strong potential for on-site testing applications.

ObjectiveTo investigate the effect of icariin （ICA） on steroid-induced ferroptosis in bone microvascular endothelial cells （BMECs）. MethodsRat BMECs were selected and treated with 500 mg·L^-1 hydrocortisone for 1.5 h to establish a ferroptosis model of BMECs. The experimental cells were divided into a blank group， hormone group （500 mg·L^-1 hydrocortisone）， ICA group （500 mg·L^-1 hydrocortisone + 34 mg·L^-1 ICA）， and ferroptosis agonist group （500 mg·L^-1 hydrocortisone + 34 mg·L^-1 ICA + 2.7 mg·L^-1 erastin）. Cell viability was detected by CCK-8. The levels of ferrous ion， glutathione （GSH）， malondialdehyde （MDA）， superoxide dismutase （SOD）， and reactive oxygen species （ROS） were detected by related kit species. The ferroptosis-related proteins， such as glutathione peroxidase 4（GPX4）， ferritin light chain （FTL）， and transferrin receptor protein1 （sTfR） were detected by Western blot， as well as autophagy-related proteins including microtubule-associated protein 1 light chain 3B （LC3B）， Beclin1， B-cell lymphoma-2 （Bcl-2）， and Caspase-3. Results500 mg·L^-1 hydrocortisone intervention for 1.5 h could effectively induce ferroptosis in BMECs， and ferroptosis levels could reach a peak as the intervention continued. In terms of cellular antioxidant capacity， compared with those in the blank group， the cell vitality， GSH in the hormone group decreased significantly， and the levels of ROS， SOD， MDA， and ferrous ions were significantly increased （P<0.01）. Compared with those in the hormone group， the cell viability， GSH were significantly increased， and the levels of ROS， SOD， MDA， and ferrous ions were decreased in the ICA group （P<0.01）. Compared with those in the ICA group， the cell vitality， GSH in the ferroptosis agonist group decreased significantly， and the levels of ROS， SOD， MDA， and ferrous ions increased significantly （P<0.01）. In terms of the relationship between ferroptosis and autophagy， compared with the blank group， the hormone group had significantly increased expression levels of LC3B， sTfR， Beclin1， and FTL and significantly decreased expression levels of GPX4 （P<0.01）. Compared with the hormone group， The ICA group had significantly decreased expression levels of LC3B， sTfR， and FTL and significantly increased expression levels of Beclin 1 and GPX4 （P<0.01）. Compared with those in the ICA group， the expression levels of LC3B， sTfR， and FTL increased in the rapamycin group， and those of Beclin 1 and GPX4 decreased （P<0.01）. In terms of cell ferroptosis and apoptosis，compared with the blank group， the hormone group had significantly increased expression levels of FTL， sTfR and Caspase-3 and significantly decreased expression levels of GPX4， and Bcl-2 （P<0.01）. Compared with the hormone group， the ICA group had significantly decreased expression levels of FTL， sTfR and Caspase-3 and significantly increased expression levels of GPX4， and Bcl-2 （P<0.01）. Compared with those in the ICA group， the expression levels of FTL， sTfR and Caspase-3 in the ferroptosis agonist group were increased， and the expression levels of GPX4， and Bcl-2 were decreased （P<0.01）. In terms of cell function，compared with that in the blank group， the ability of cell migration and tube formation was significantly decreased in the hormone group （P<0.01）. Compared with that in the hormone group， the cell migration and tube formation ability in the ICA group were significantly increased （P<0.01）. ConclusionFerroptosis is involved in steroid-induced damage in BMECs. ICA can inhibit steroid-induced ferroptosis in BMECs， and the mechanism may be associated with the inhibition of ferroptosis by regulating autophagy.