In order to locate the level of nitroquine action on the folate metabolism, ni-troquine was given to the mice infected with P. berghei or P. yoelii. To the first group of mice, different doses of nitroquine were given to its five subgroups. The second group of mice received the same doses of nitroquine as the first group but calcium leucovorin (folinic acid) 6 mg/kg/day intramuscularly, folic acid 20 mg/kg/day intramuscularly, or PABA 20 mg/kg/day orally were given to different subgroups respectively at the same time. It was found that the dose-effective curve of nitroquine was shifted to the right when PABA was administered simultaneously and the CD50 of nitroquine at that time was larger than that of nitroquine used singly. Both calcium leucovorin and folic acid essentially showed no antigonistic effects.From the antigonistic action of PABA against nitroquine) it is suggested that nitroquine is likely to achieve its antimalarial effect through its competition for dihydropteric acid synthetase with PABA. Other chains on the folic acid metabolism were also discussed.

Objective    To discuss the safety and feasibility of no chest tube (NCT) after thoracoscopic pneumonectomy. Methods    The online databases including PubMed, EMbase, The Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), WanFang Database, VIP, China Biology Medicine disc (CBMdisc) were searched by computer from inception to October 2020 to collect the research on NCT after thoracoscopic pneumonectomy. Two reviewers independently screened the literature, extracted the data, and evaluated the quality of the included studies. The RevMan 5.3 software was used for meta-analysis. Results    A total of 17 studies were included. There were 12 cohort studies and 5 randomized controlled trials including 1 572 patients with 779 patients in the NCT group and 793 patients in the chest tube placement (CTP) group. Meta–analysis results showed that the length of postoperative hospital stay in the NCT group was shorter than that in the CTP group (SMD=–1.23, 95%CI –1.59 to –0.87, P<0.000 01). Patients in the NCT group experienced slighter pain than those in the CTP group at postoperative day (POD)1 (SMD=–0.97, 95%CI –1.42 to –0.53, P<0.000 1), and POD2 (SMD=–1.10, 95%CI –2.00 to –0.20, P=0.02), while no statistical difference was found between the two groups in the visual analogue scale of POD3 (SMD=–0.92, 95%CI –1.91 to 0.07, P=0.07). There was no statistical difference in the 30-day complication rate (RR=0.93, 95%CI 0.61 to 1.44, P=0.76), the rate of postoperative chest drainage (RR=1.51, 95%CI 0.68 to 3.37, P=0.31) or the rate of thoracocentesis (RR=2.81, 95%CI 0.91 to 8.64, P=0.07) between the two groups. No death occurred in the perioperative period in both groups. Conclusion    It is feasible and safe to omit the chest tube after thoracoscopic pneumonectomy for patients who meet the criteria.