Objective To investigate the effects of exposure to cigarette smoke on the counts and functions of tolerogenic dendritic cells(tDC) and regulatory T cells(Treg) in a mouse model of asthma. Methods Forty female BALB/c mice at age 20 days were randomly allocated into four groups including the normal saline ( NS)/air treatment group, the NS/cigarette smoke ( CS) treatment group, the ovalbumin (OVA)/air treatment group and the OVA/CS treatment group (n=10).A mouse model of asthma was es-tablished by intraperitoneally injecting OVA in an interval of two weeks to cigarette smoke for three weeks. The percentages of Treg cells in PBMCs and the changes of CD80 and CD86 expression on the surface of DCs of the mice in each group were analyzed by flow cytometry analysis.The transcriptional levels of forkhead box P3 ( Foxp3) in lung tissues were measured by real-time quantitative PCR.The levels of IFN-γ, IL-4, IL-6, IL-10, IL-12p40, IL-17A and TGF-β1 in bronchoalveolar lavage fluid ( BALF) samples were measured by ELISA.Results Exposing young mice to cigarette smoke significantly increased the percentages of Treg cells in PBMCs and the expression of Foxp3 at mRNA level in lung tissues of mice with asthma.High levels of TGF-β1 and IL-10 were detected in BALF samples of the heathy mice and those with asthma exposed to CS at a young age.The mice with asthma exposed to CS at an early age showed decreased expression of CD80 and CD86 on the surface of DCs.Lower levels of IL-12p40 and IL-6 and higher levels of IFN-γ, IL-4 and IL-17A in BALF samples were observed in mice from the OVA/CS treatment group.Conclusion Expo-sing to cigarette smoke at an early age was involved in the dysfunction of T cell-mediated immune responses in mice with asthma.This study might provide new ideas for the prevention and treatment of asthma.

Objective To investigate the effect of hyperbaric oxygen intervention at different time on the neural stem cell proliferation and differentiation in dentate gyrus subgranular zone (SGZ) of adult rats after acute focal cerebral ischemia.Methods Totally 48 Sprague-Dawley male adult rats were randomly divided into a middle cerebral artery occlusion (MCAO) group, a hyperbaric oxygen group, a hyperbaric air group and a normobaric oxygen group, each of 12.A middle cerebral artery occlusion (MCAO) model was induced to all rats using the modified Zea-Longa's method of intraluminal filament occlusion, Except the MCAO group, the other 3 groups received corresponding hyperbaric oxygen, hyperbaric air and normobaric oxygen intervention once a day two hours after the suture insertion.The rats were sacrificed for double-label immunofluorescent analysis at 2 days, 3 days, 7 days and 14 days after brain ischemia.BrdU +/nestin + labeled the proliferated neural stem cells, and BrdU +/DCX + labeled its differentiated derivates, early neurons, in SGZ of ischemic hippocampus dentate gyrus.Also, the cell number was calculated under the fluorescence microscope.Results Two days after brain ischemia, the numbers of BrdU/nestin and BrdU/DCX cells in SGZ in the hyperbaric oxygen group were (2340.45 ± 1109.59) and (5520.66 ± 1103.09) respectively, which had increased significantly, compared with the hyperbaric air group and normobaric oxygen group (P ＜ 0.05).Three and 7 days after brain ischemia, the numbers of BrdU/nestin and BrdU/DCX cells in SGZ in the hyperbaric oxygen group had shown significant increase compared with the other 3 groups (P ＜ 0.05).Fourteen days after brain ischemia, the numbers of BrdU/DCX cells in SGZ in the hyperbaric oxygen group had significantly increased compared with the hyperbaric air group, normobaric oxygen group and the MCAO group (P ＜ 0.05).Conclusion Hyperbaric oxygen promotes the proliferation and differentiation of neural stem cells in ischemic SGZ.

Objective:To investigate the positive rates of 2019-nCoV nucleic acid in different specimens from confirmed COVID-19 cases during hospitalization and after discharge.Methods:Patients with confirmed COVID-19 were enrolled from designated hospitals. Nasal swabs, throat swabs, and specimens of stool, urine and blood were collected during hospitalization. After the patients were discharged, nasal swabs, throat swabs and stool specimens were collected during follow-up. Real-time RT-PCR was used to detect 2019-nCoV nucleic acid.Results:This study involved 25 confirmed COVID-19 cases. During hospitalization, all patients tested positive in both nasal and throat swab 2019-nCoV nucleic acid tests, and nine of them (36.00%) were positive in stool specimen test. Urine and blood specimen test results were all negative. Nasal swabs, throat swabs and stool specimens were collected from each patient 7 d and 14 d after discharge. Two patients (8.00%) tested positive for 2019-nCoV nucleic acid again in nasal and throat swab tests on 7 d, while all stool specimen tests were negative. No 2019-nCoV nucleic acid was detected in nasal swabs, throat swabs or stool samples on 14 d.Conclusions:2019-nCoV nucleic acid was detected in stool samples of confirmed COVID-19 cases during hospitalization. Nasal and throat swab nucleic acid tests turned positive again in some patients after discharge.

Objective:To explore the positive rates of 2019-nCoV nucleic acid at different time of courses of COVID-19.Methods:Patients with confirmed COVID-19 were enrolled in this study. Nasal and throat swabs were collected from different courses of disease. Real-time RT-PCR was used to detect 2019-nCoV nucleic acid.Results:From January 23 to February 20, 2020, a total of 120 confirmed cases of COVID-19 were reported in Xi’an, and 85 cases(70.83%) were positive in first detection. The COVID-19 cases included consistently nucleic acid positive and intermittently nucleic acid positive patients. 2019-nCoV nucleic acid could be detected in incubation period, and the longest observed duration of nucleic acid positive in this study was 26 days. The positive rate of 2019-nCoV nucleic acid was up to 84.21% on the 6th day, and the positive rate decreased as time passed during the course of COVID-19. Three patients (2.86%) were tested positive for 2019-nCoV nucleic acid again in nasal and throat swabs after discharge.Conclusions:The positive rate of 2019-nCoV nucleic acid was higher in the early stage of disease. 2019-nCoV nucleic acid can be detected in incubation period, and virus shedding may last for a long period.