Objective:To study the clinical characteristics of ureaplasma urealyticum (UU) infection in preterm infants with gestational age <34 weeks.Methods:From January 2017 to December 2021, premature infants with gestational age <34 weeks admitted to neonatal department of our hospital were enrolled in this prospective cohort study. UU-DNA from respiratory tract samples were examined using quantitative fluorescence polymerase chain reaction method. The infants were assigned into UU (+) group and UU (-) group. Perinatal factors and clinical characteristics were compared between the two groups.Results:A total of 182 preterm infants were enrolled, including 59 cases (32.4%) in UU (+) group and 123 (67.6%) in UU (-) group. UU (+) group had significantly lower gestational age and birth weight and significantly higher incidences of vaginal delivery, premature rupture of membranes (PROM) >18 h and maternal chorioamnionitis than UU (-) group ( P<0.05). Compared with UU (-) group, UU (+) group had significantly higher leucocyte count, neutrophil count and interleukin-6 at 1, 24 and 72 h after birth ( P<0.05). No significant differences existed in C-reactive protein and procalcitonin between the two groups at each time point ( P>0.05). In UU (+) group, the incidences of intrauterine pulmonary infection and bronchopulmonary dysplasia (BPD) were higher and the incidence of respiratory distress syndrome was lower than UU (-) group ( P<0.05). No significant differences existed in the incidences of intraventricular hemorrhage, periventricular leukomalacia, feeding intolerance, necrotizing enterocolitis, retinopathy of prematurity between the two groups ( P>0.0 5). UU (+) group had significantly longer duration of oxygen therapy than UU (-) group ( P<0.05). No significant differences existed in the duration of invasive mechanical ventilation and hospital stay between the two groups ( P>0.05). Conclusions:Preterm infants <34 weeks with positive UU in respiratory tract secretions have higher incidences of vaginal delivery, PROM>18 h and maternal chorioamnionitis. Leukocyte and neutrophil count and interleukin -6 are higher in these infants. They need prolonged oxygen therapy and have increased risks of intrauterine pulmonary infection and BPD.

Objective To explore the effects of graphene oxide (GO)-polyethylene glycol (PEG)-folic acid (FA)-pyrenemethylamine hydrochloride (PyNH2)-mediated RNA interference (RNAi) of hypoxia-inducible factor-1α (HIF-1α) on the biological behaviors of human pancreatic cancer Patu8988 cells.Methods GO-PEG-FA-PyNH2 and RNAi targeting HIF-1α gene (GO-PEG-FA-PyNH2-HIF-1α-RNAi)was constructed.The expressions of HIF-1α and glucose transporter 1 (Glut-l) in Patu8988 cells were determined after knockdown of HIF-1α by RNAi.The invasive ability,the proliferation and the cell cycle of Patu8988 cells were investigated.The effect of HIF-1α knockdown on the uptake of 18F-fluorodeoxyglucose (FDG) in Patu8988 cells was also detected.Comparison of data was conducted by one-way analysis of variance and least significant difference t test.Results The GO-PEG-FA-PyNH2 was successfully constructed,and no cytotoxicity was found.Under the hypoxia or normoxia state,the mRNA and protein levels of HIF-1α and mRNA level of Glut-1 in cells transfected with GO-PEG-FA-PyNH2-HIF-1α-RNAi (study group) were lower than those in cells transfected with GO-PEG-FA-PyNH2 (negative group) and cells transfected with Opti-minimal essential medium (Opti-MEM,control group;F=30.25-32.58,t=3.66-5.81,all P＜0.05);the numbers of migrated cells in the study group were much lower than those in the negative group and the control group (F=38.63 and 41.35,t=20.51-35.25,all P＜0.01);the cell proliferation in the study group was significantly lower than that in the negative group and the control group (F=35.19 and 38.11,t =15.11-22.19,all P＜0.05).The proportions of G0/G1 cells in the study group were higher than those in the negative group and the control group (F=34.60 and 34.83,t=11.55-34.56,all P＜0.05);the 18 F-FDG uptake in the study group was lower than that in the negative group and control group (F=29.85 and 31.69,t =3.35-4.35,all P＜0.05).Conclusion GO-PEG-FA-PyNH2-mediated HIF-1α RNAi inhibits the expression of HIF-1α in pancreatic cancer cells,leading to changes in related biological behaviors.

Objective To investigate the changes of plasma cortisol and adrenocorticotrophic hormone(ACTH)levels in prema-ture neonates with the infectious diseases.Methods Ninety premature neonates in the neonatal department of our hospital were di-vided into the control group(30 cases),mild infection group(30 cases)and severe infection group(30 cases).The radioimmunoassay was adopted to detect the serum cortisol and ACTH levels on 1,3,7 d after birth in all subjects and the corresponding comparison was conducted.Results The cortisol levels on 1,3,7 d in the mild infection group were (193.04 ±39.48),(151.12 ±35.62 ), (128.37±27.47)ng/mL respectively,the level on 1 d was higher than that on 3,7 d (P <0.05),and the 3 d was higher than that on 7 d (P <0.05).The cortisol level on 1,3,7 d in the severe infection group were (99.43±50.17),(96.52 ±44.69),(131.13 ± 42.73)ng/mL respectively,and the level on 1,3 d was significantly lower than that on 7 d (P <0.05).Conclusion The relative ad-renocortical insufficiency exists in premature neonates with the early stage of severe infection and is manifested by the decline of plasma cortisol level,which could recover to the normal level on 7 d,but the plasma ACTH level has no relation with infection.

Objective To evaluate the relationship between 18F-FDG uptake and P-gp expression in Bcap37 or Bcap37/MDR1 tumor-bearing BALB/c nude mice.Methods Bcap37 or Bcap37/MDR1 cells were injected into BALB/c nude mice (1× 107cells/ml,0.2 ml/mouse) to construct mice models.Bcap37 (n=5) or Bcap37/MDR1 (n=5) tumor-bearing mice fasted for 6 h before imaging.After anesthesia,the mice were injected with 7.4 MBq of 18F-FDG via tail vein.The dynamic microPET scans were carried out for 90 min.On the microPET images,the ROI was drawn and the TAC was obtained.The next day,those 10 mice underwent dynamic microPET scans after injected with elacridar (GF120918) and 18F-FDG.Another 10 mice,5 with Bcap37 tumors and 5 with Bcap37/MDR1 tumors,were used.After 7.4 MBq 18F-FDG with or without 2.0 mg/kg GF120918 was administered via tail vein,microPET images were acquired at 60 min.ROI was drawn over the tumors and SUV was obtained.Two-sample t test was used to analyze the data.Results GF120918 did not significantly alter the 18F-FDG accumulation curve in Bcap37 tumors,but significantly enhanced the 18F-FDG accumulation in Bcap37/MDR1 tumors.GF120918 did not influence 18F-FDG uptake (SUV) in Bcap37 tumors (1.052±0.028,1.028±0.045,t =1.792,P＞0.05),but significantly increased the SUV in Bcap37/MDR1 tumors (1.015±0.043,0.712±0.031,t=3.365,P＜0.05);The SUV of 18 F-FDG in Bcap37 tumors was significantly higher than that in Bcap37/MDR1 tumors without injection of GF120918 (t =3.952,P＜0.05).The SUV was not significantly different when GF120118 was injected (t=1.835,P＞0.05).Conclusions 18F-FDG is a substrate of P-gp.18F-FDG imaging combined with GF120918 injection may be an effective noninvasive method for the detection of tumor's MDR.

Objective To evaluate the effect of P-gp inhibitors of verapamil (VER) and GF120918 on 18F-FDG uptake in Bcap37 and Bcap37/multidrug resistancce (MDR)1 cell lines in vitro,and to explore the relationship between 18F-FDG uptake and P-gp expression at cellular level.Methods Bcap37 and Bcap37/MDR1 cells were seeded into 6-well plates at a density of 1 × 106 per well.Three days later,37 kBq/ml 18F-FDG,or 37 kBq/ml 18F-FDG + 100 μmoL/L VER,or 37 kBq/ml 18F-FDG + 50 μmol/L GF120918 were added into each well.Mter incubated for 10,30,60 and 120 min at 37 ℃ and in 5％ CO2,the medium was removed and the cells were washed three times with 1 ml ice-cold PBS immediately.The radioactivity of 18 F-FDG was measured using a gamma counter.The uptake of 18F-FDG was expressed as the ratio of 18F-FDG radioactivity in Bcap37 or Bcap37/MDR1 cells and the overall radioactivity added to the cells in each well.The t test was used for statistical analysis.Results 18F-FDG uptake was higher in Bcap37/MDR1 cells than that in Bcap37 cells after incubated for 10 min.The uptake rate was (1.88 ±0.19) ％ in Bcap37/MDR1 cells and (1.37 ± 0.18) ％ in Bcap37 cells (t =7.832,P ＜ 0.05).On the contrary,18 F-FDG uptake was significantly higher in Bcap37 cells than that in Bcap37/MDR1 cells after incubated for 60 and 120 min.The uptake rates were (2.29 ±0.23)％ and (2.34 ±0.15)％ in Bcap37 cells,(1.47 ±0.14)％ and (1.53 ±0.22)％ in Bcap37/MDR1 cells (t =8.437,8.283,both P ＜ 0.05).18 F-FDG uptake was significantly higher with VER or GF120918 in Bcap37/MDR1 cells than that without VER or GF120918 after the incubation of 60 and 120 min (t =9.032,9.243 and 8.765,8.803,all P ＜ 0.05).The uptake rates with VER or GF120918 were (2.45 ±0.21)％ and (2.46 ±0.25)％,(2.50 ±0.24)％ and (2.48 ±0.27)％.There was no significant difference of 18F-FDG uptake in Bcap37 cells with or without VER or GF120918.Conclusions 18F-FDG is a substrate of P-gp at cellular level.P-gp may act as an efflux pump to reduce 18F-FDG uptake in Bcap37/MDR1 cells.The uptake of 18F-FDG can be used to evaluate the function of P-gp in tumor cells.