Objective To evaluate the effectiveness of noninvasive positive pressure ventilation(NPPV) as a weaning strategy in patients with acute respiratory failure after failure to wean from invasive positive pressure ventilation(IPPV). Method A prospective randomized and controlled clinical trial of weaning of IPPV was carried out in patients mechanically ventilated in mode of IPPV for more than 48 hours with failure in a spontaneous breathing trial(SBT: PSV 6 cmH_2O). Patients with contraindications to NPPV were excluded. After failure the SBT, patients were randomly divided(random number) in two groups. Patients in NPPV group were extubated after being ventilated with high pressure support for 30 minutes and then placed on NPPV. Patients in IPPV group were weaned following conventional procedure. Arterial blood gases, maximal inspiratory pressure, respiratory rate,tidal volume, rapid shallow breathing index, heart rate, arterial blood pressure, and peripheral oxygen saturation were measured before and after failing the SBT. The rate of complications, including pneumonia and tracheotomy duration mechanical ventilation, days of hospital stay and outcome were observed. Findings of the two groups were vompared using the Student t test and the chi-square test. Results The percentage of complications in the NPPV group was lower(22.9% versus 72.2%, P <0.01) ,with lower incidences of pneumonia(6.1%,36.1%; P <0.01) and tracheotomy. Compared between the two groups, days of ICU stay( 14.16(3.45) d vs. 22.57( 7.71 ) d; P <0.01) and total days of mechanical ventilation(14.88±3.76 days vs. 20.68± 2.79 days, P <0.01) of NPPV group are shorter than IPPV group. Conclusions NPPV is a good alternative to the mechanically venti-lated patients who fail in initial weaning attempts. The key to successful NPPV weaning is the proper selection of weaning candidates and using NPPV as soon as possible after extubation.

Objective:To prepare a novel tri-specific T cell engager (19TriTE) targeting CD19 antigen, and to investigate its immunotherapeutic effect on CD19-positive hematological malignancies.Methods:19TriTE was constructed by molecular cloning technology and successfully expressed through the eukaryotic expressing system. The effects of 19TriTE on the proliferation and activation of T cells, as well as the specific cytotoxicity against CD19 positive tumor cell lines were verified.Results:①19TriTE expressing plasmid was constructed and successfully expressed through the eukaryotic expressing system. ②19TriTE can specifically bind to T cells and Nalm6 cells, with equilibrium dissociation constants of 19.21 nmol/L and 11.67 nmol/L, respectively. ③The expression rates of CD69 positive T cells and CD25 positive T cells were 35.4% and 49.8% respectively, when 2 nmol/L 19TriTE were added in the co-culture system, which were significantly higher than those in the control group. ④19TriTE can significantly promote the proliferation of T cells. The absolute count of T cells expanded from the initial one million to 74 million with an 74 fold increase at the concentration of 1 nmol/L on day 12. ⑤19TriTE can significantly mediate T cells killing of CD19 positive target cells in a dose-dependent manner. At the concentration of 10 nmol/L, the target cells lysis reached 50%. ⑥Degranulation experiment verified that 19TriTE can activate T cells in the presence of CD19 positive target cells, and the activation of T cells positively correlated with the dose of 19TriTE. ⑦When 19TriTE fusion protein co-cultured with T cells and target cells overexpression RFP and luciferase genes respectively, 19TriTE can notably mediate T cells killing of CD19 positive target cells through fluorescent microscope or bioluminescence imaging technology.Conclusion:In this study, we successfully constructed and expressed 19TriTE fusion protein and verified that it can effectively activate T cells and promote their proliferation in vitro. At the same time, it can bind to CD19 positive target cells and T cells, as well as enhance T cells anti-leukemia effect in vitro, providing the foundation for further clinical research.