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Background: Rickets occurs in infants and children (aged 2 months to 3 years), compromising their skeletal development and damaging nervous, hematopoietic, immune, and other system functions. This study aimed to explore the significance of CD38 in rickets., Methods: The microarray dataset GSE22523 was analyzed to obtain differentially expressed genes in rickets patients. A total of 36 rickets patients and healthy controls were recruited for the study, and their blood samples were collected, followed by detecting mRNA levels of CD38 using quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, the significance of CD38 in rickets patients was analyzed by receiver operating characteristic (ROC) analysis, while the correlation between CD38 and 25-hydroxy-vitamin D (25OHD)/parathyroid hormone (PTH) was analyzed with Pearson's correlation., Results: Results showed that CD38 mRNA levels and PTH contents were significantly increased in the rickets patients while 25OHD contents were decreased. Correlation analysis indicated that CD38 was positively correlated with PTH and negatively correlated with 25OHD in both serum and plasma samples of rickets patients. Moreover, ROC analysis showed that serum CD38 was 0.9005 (95 % CI: 0.8313-0.9696), and the AUCs of plasma CD38 was 0.7215 (95 % CI: 0.6031-0.8398) in differentiating rickets patients from healthy persons, advocating serum CD38 had better diagnostic value., Conclusion: CD38 mRNA levels were upregulated in rickets patients and closely correlated with PTH and 25OHD contents, indicating CD38 might be a diagnostic marker of rickets patients. Further research on the diagnostic utility of CD38 is necessary for the diagnosis and treatment of ricketsin rickets in the future., Competing Interests: Declaration of competing interest The authors have no relevant financial or non-financial interests to disclose., (Copyright © 2024. Published by Elsevier Ltd.)

Purpose: The simultaneous and ipsilateral occurrence of medial epicondylar and radial neck fractures is rare. This study evaluated the clinical and radiological outcomes of medial to lateral diagonal injury of the elbow (MELAINE)., Methods: Six males and 6 females were diagnosed with MELAINE (left: 10, 83.3%; right: 2, 16.7%). Medial epicondylar and radial neck fractures were classified according to Papavasiliou's classification (seven type II, two type III, three type IV) and Judet's classification (three type I, four type II and five type III), respectively. All patients underwent surgery. The carrying angle, range of motion, and Kim et al. Elbow Performance Score were used to evaluate clinical and functional outcomes; related complications were recorded., Results: Mean age at injury and mean follow-up were 11.1 ± 2.5 (range, 6-14) and 40 ± 25.6 months (range, 13-90), respectively. All fractures consolidated in 6.3 ± 1.2 weeks on average (4-9). Outcomes were good (n = 1; 8.3%) to excellent (n = 11; 91.7%). The carrying angle of the injured and uninjured side was 15.5°± 2.6° and 14.7°± 2°, respectively (p = 0.218). The range of motion of elbow flexion-extension and forearm pronation-supination of the injured side was 144.2°± 10.4°, 4.6°± 5.4°, 76.7°± 9.1°, 80.4°± 9.2°, respectively, with no significant differences from the healthy side (p > 0.05). The Elbow Performance Score of the injured and uninjured side was 96.3 ± 5.3 and 98.8 ± 2.3, respectively (p = 0.139). No cases of infection, cubitus valgus, stiffness, or instability were recorded., Conclusion: Although uncommon, MELAINE should not be neglected. Surgery aims to stabilize the elbow and avoid valgus deformity. If diagnosed and treated, clinical and radiological results are excellent in most cases., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.)

Background: Capitellum fractures are rare coronal fractures of the distal humerus which accounts for 6% of all distal humeral fractures and only 1% of all elbow fractures. The purpose of this study was to investigate the efficacy and complications of arthroscopically assisted reduction and fixation with absorbable screws for capitellar fracture of the humerus in children., Methods: This was a retrospective case series study, which considered four patients (4 elbows), ranging from 10 to 15 years old, who were treated by arthroscopic-assisted percutaneous absorbable screw between 2018 and 2020. The elbow flexion-extension and forearm supination-pronation ranges of motion (ROM) were measured at the preoperative examination and last follow-up examination. Finally, the clinical and radiological results were assessed., Results: The result of operations is satisfactory. The mean follow-up was 3.0 years (range 2-3.8 years). Average range of motion significantly improved from pre- to postoperation, with forearm supination from 60°(50°-60°) to 90°(90°) and pronation improved from 75°(70°-80°) to 90°(90°). The postoperative elbow flexion-extension range of motion was significantly higher compared with range of motion before surgery ( P  < 0.001; r  = 0.949). At the final follow-up examination, the Mayo Elbow Performance Score was excellent. Satisfactory clinical results were achieved in all patients, and no postoperative complications were observed., Conclusions: It is an effective and safe surgical option to use arthroscopic-assisted percutaneous absorbable screw fixation for treating capitellum fracture of the humerus without any complications in children., Level of Evidence: Level IV; case series., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 You, Cheng, Xia, Deng, Zhou, Sun and Fu.)

Introduction: The aim of this was to analyze the effect of different treatment options on radial neck fractures in children and to explore the factors affecting the prognosis of fractures., Methods: The clinical data of 131 children with radial neck fractures admitted to our hospital from 2010 to 2018 were retrospectively analyzed, and the patients were divided into 6 groups according to treatment methods [manual reduction with Kirschner wires (K-wires) for internal fixation (group A); manual reduction with elastic stable intramedullary nails (ESINs) for internal fixation (group B); leverage reduction with K-wires for internal fixation (group C); leverage reduction with ESINs for internal fixation (group D); manual and leverage reduction with K-wires/ESINs for internal fixation (group E); and open reduction with K-wires/ESINs for internal fixation (group F)]. Postoperative elbow function and complications were analyzed., Results: Among the 131 patients with fractures, the median age was 8 years, the median preoperative angulation was 52°, the follow-up rate was 86.3% (113/131), the average follow-up time was 58.3 months, and the postoperative complication rate was 17.7% (20/113). The comparison among the different treatment groups showed that group B had the best recovery of elbow function, postoperatively, and the lowest postoperative complication rate. Age, duration of hospitalization, and preoperative angulation were independent factors affecting postoperative complications. Older age, longer duration of hospitalization, and higher angulation increase the postoperative complications., Conclusion: Different treatment options have different efficacies for radial neck fractures in children, of which manipulative reduction with internal fixation using ESINs can achieve good efficacy and a low postoperative complication rate. Age, duration of hospitalization, and preoperative angulation are independent factors for postoperative complications., (© 2021. The Author(s).)

Background: Hepatoblastoma (HB) is the most common primary malignant liver tumor in children. The prognosis of HB metastasis is poor, despite the increasing diversity of treatment. Piezo, a ubiquitously expressed membrane mechano-transduction protein, is involved in the process of tumor cell migration. Under the gene expression profiling interactive analysis (GEPIA) database, Piezo1 was highly expressed in HB and negatively correlated with the overall survival time., Methods: Firstly, the expression of Piezo1 in both paracancerous and HB tissues (n = 7) was detected, and the prognostic value of Piezo1 was assessed in HB (n = 160) patients. Secondly, the inhibition and overexpression of Piezo1were executed in two HB cell lines, HepG2 and Huh 6. Methyl thiazolyl tetrazolium (MTT), wound healing and trans-well assays were performed to identify the effect of Piezo1 on the proliferation and metastasis of HB cells, respectively. In addition, a co-immunoprecipitation assay was performed to determine whether Piezo1 has an interaction with HIF-1α. Finally, the expressions level of Piezo1, HIF-1α, and VEGF by overexpression/inhibition each other were detected by RT-qPCR and western blots to find a possible signaling channel in HB metastasis., Results: We found that Piezo1 was highly expressed in HB tissues and associated with poor prognosis of patients. Piezo1 was related to cell proliferation in HepG2 and Huh 6 cells. We also found that Piezo1 stimulated HIF-1α expression. Meanwhile, overexpression of Piezo1 promoted the migration and invasion of HB cells, while the promotion was not detected when HIF-1α was suppressed. Additionally, the silencing of HIF-1α inhibited the expression of VEGF, but showed no effect on Piezo1 expression., Conclusion: In this study, we identified that Piezo1 was involved in HB metastasis, and the Piezo1-HIF-1α-VEGF axis could be a possible signaling pathway in HB metastasis., Competing Interests: The authors declare no conflict of interest., (© 2022 Published by Elsevier Ltd.)

Background: The purpose of this study was to introduce the arthroscopic internal drainage with anterior-anteromedial approach for the treatment of popliteal cysts in children. To compare its clinical efficacy with open surgery., Methods: This was a retrospective case-control study of 102 patients diagnosed with popliteal cysts from January 2018 to February 2020 who received surgery. The study included 27 cases with minimally invasive group (MI group) and 75 cases with open surgery group (OS group). The MI group included 21 males and 6 females, age 6.71 ± 2.16 years who received arthroscopic internal drainage of the cysts to adequately widen the valve opening between the cyst and the articular cavity, excised the fibrous diaphragm without complete excision of the cyst wall. The OS group included 57 males and 18 females, age 6.21 ± 1.67 years who received open excision. The clinical parameters regarding the preoperative characteristics and surgical results were compared. Ultrasound or MRI was used to identify the recurrence of the popliteal cysts. Rauschning-Lindgren grade was recorded to evaluate the clinical outcome., Results: All patients were followed up for at least 24 months. There were no significant differences between the two groups in age, gender, left and right sides, disease time, cyst size, length of hospitalization, preoperative Rauschning-Lindgren grade (p > 0.05). At the last follow-up, the preoperative and postoperative Rauschning-Lindgren grade was improved in both groups. Compared with the OS group, operation time was significantly shortened in the MI group (28.89 ± 4.51 min vs 52.96 ± 29.72 min, p < 0.05). The MI group was superior to the OS group in terms of blood loss and plaster fixation, with statistical significance (p < 0.05). There was obvious difference in recurrence rate between the two groups (0% vs 17.33%, p = 0.018). No postoperative complications occurred during the follow-up period., Conclusions: Compared with open excision, the treatment of popliteal cyst in children by arthroscopic internal drainage to expand the articular cavity and eliminate the "one-way valve" mechanism between the cyst and the articular cavity exhibits better clinical outcomes and significantly reduces the recurrence rate, which is worthy of further clinical promotion., (© 2022. The Author(s).)

Introduction: Musculoskeletal infection (MSI) is a common cause of morbidity among the paediatric population. Some clinicians recommend withholding prophylactic antibiotics until culture collection with an aim to improve the culture sensitivity. However, a recent retrospective study reported that prophylactic antibiotic administration did not affect culture sensitivities in either disseminated or local MSI in paediatric population, which is surprising. The aim of the present study is to investigate the effects of prophylactic antibiotic administration and the timing of antibiotic administration on culture sensitivity and clinical outcomes of paediatric MSI., Methods and Analysis: A randomised controlled clinical trial will be carried out. Individuals aged 0-18 years with a diagnosis of MSI will be screened and evaluated at the Shenzhen Children's Hospital. The participants will be randomly allocated into four groups, and they will receive the antibiotic treatment at different time points, that is, 1 week, 3 days, 1 day prior to tissue culture collection and 1 day after tissue culture collection, respectively. The primary outcome will be culture sensitivity. In addition, the disease-related markers including white blood cell count, C reactive protein, erythrocyte sedimentation rate, vital signs as well as the length of hospital stay will be measured or recorded accordingly. Using χ 2 tests, the rates of positive cultures will be compared between different groups. Statistical comparisons between the different patient groups regarding the confounding and outcome variables will be conducted using independent t-tests, Mann-Whitney U tests, χ 2 tests and Fisher's exact tests as appropriate with the significance level set to 5% (p<0.05)., Ethics and Dissemination: This study has received ethical approval. The findings will be disseminated both in scientific conferences and peer-reviewed journal., Trial Registration Number: ChiCTR2100041631., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The effect of ozone exposure on neuroendocrine responses in humans has not been fully studied., Methods: We conducted a longitudinal panel study with four rounds of visits among 43 college students in Shanghai, China, from May to October 2016. For each visit, we monitored personal real-time ozone exposure for consecutive 3 days (from 8:00 a.m. to 6:00p.m. each day), followed by blood sample collection. We measured serum levels of three hormones in the hypothalamus-pituitaryadrenal (HPA) axis, including corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and cortisol, and three catacholamines indicating sympathetic-adrenal-medullary (SAM) axis activation, including adrenaline, noradrenaline, and dopamine. We applied linear mixed-effect models to evaluate the associations between ozone exposure and these neurohormones and further compared models using personal and fixed-site ozone measurements., Main Results: At lag 0-8 h, personal ozone exposure ranged from 4.5 ppb to 104.3 ppb with an average of 21.0 ± 14.7 ppb, which was approximately half of the ambient ozone concentration. Per 10-ppb increase in personal ozone exposure (lag 0-8 h) was associated with increases of 5.60% [95% confidence interval (CI): 2.30%, 9.01%] in CRH, 5.91% (95% CI: 0.55%, 11.56%) in cortisol, and 10.13% (95% CI: 2.75%, 18.05%) in noradrenaline, whereas associated with a 12.15% (95% CI: 1.23%, 21.87%) decrease in dopamine. Overall, models using personal ozone measurements yielded larger effect estimates and better model fits than models using fixed-site measurements., Conclusions: Short-term exposure to low levels of ozone may lead to activation of the HPA and SAM axes., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

What Is Already Known on This Topic?: It remains inconclusive whether short-term ozone exposure can cause an inflammatory response and oxidative damage in the circulatory system, particularly at low concentrations., What Is Added by This Report?: This study made an accurate exposure assessment by conducting personal ozone monitoring, thus minimizing the exposure misclassification commonly found in previous environmental epidemiological studies. Our study found that even short-term exposure to low concentrations of ozone was associated with inflammation, lipid peroxidation, and mitochondrial oxidative damage., What Are the Implications for Public Health Practice?: Short-term exposure to low concentrations of ozone can still lead to subclinical cardiovascular effects, suggesting the current air quality standards for ozone need to be further tightened in China., (Copyright and License information: Editorial Office of CCDCW, Chinese Center for Disease Control and Prevention 2021.)

Background: Systemic inflammation is considered one of the key mechanisms in the development of cardiovascular diseases induced by fine particulate matter (PM 2.5 ) air pollution. However, evidence concerning the effects of various PM 2.5 constituents on circulating inflammatory biomarkers were limited and inconsistent., Objectives: To evaluate the associations of short-term exposure to a variety of PM 2.5 constituents with circulating inflammatory biomarkers., Methods: We conducted a panel study from May to October 2016 among 40 healthy adults in Shanghai, China. We monitored the concentrations of 27 constituents of PM 2.5 . We applied linear mixed-effect models to analyze the associations of PM 2.5 and its constituents with 7 inflammatory biomarkers, and further assessed the robustness of the associations by fitting models adjusting for PM 2.5 mass and/or their collinearity. Benjamini-Hochberg false discovery rate was used to correct for multiple comparisons., Results: The associations of PM 2.5 were strongest at lag 0 d with tumor necrosis factor-α (TNF-α), at lag 1 d with interleukin-6, interleukin-8, and interleukin-17A, at lag 02 d with monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1). After correcting for multiple comparisons in all models, Cl - , K + , Si, K, As, and Pb were significantly associated with interleukin-8; SO 4 2 - and Se were marginally significantly associated with interleukin-8; SO 4 2 - , As, and Se were marginally significantly associated with TNF-α; and Si, K, Zn, As, Se, and Pb were marginally significantly associated with MCP-1., Conclusions: Our results suggested that some constituents (SO 4 2 - , Cl - , K + , and some elements) might be mainly responsible for systemic inflammation triggered by short-term PM 2.5 exposure., (Copyright © 2019 Elsevier B.V. All rights reserved.)

To evaluate the short-term effects of filtered fresh air ventilation system on classroom indoor air and biomarkers in saliva and nasal samples in preschool children, a randomized crossover study was conducted in a kindergarten in Shanghai, China in 2016. Two classrooms at the same grade (n = 43) were selected and fresh air ventilation systems (FAVS) with high efficiency particulate air filter (HEPA) were installed. In the first week, FAVS-HEPA was run in one classroom for 2 continuous school days and the other classroom was remained as usual with no use of FAVS-HEPA. After one week of wash-out, the ventilation modes exchanged between two classrooms and another 2 days of intervention were repeated. Real-time indoor and outdoor air pollution and climate factors (PM 2.5 , Temp and relative humidity (R.H.)) were measured. Saliva and nasal internal mucosa samples were collected immediately at the end of each intervention scenario. Linear mixed-effect regression model was applied to evaluate the effects of intervention on children's health indicators controlling for age, gender, height, BMI and temperature. The results showed, with FAVS-HEPA, the classroom indoor fine particulate matter (PM 2.5 )(29.1 ± 17.9 μg/m 3 ) was on average significantly lower than that without FAVS-HEPA (85.7 ± 43.2 μg/m 3 ). By regression analysis, each 10 μg/m 3 decrease of indoor PM 2.5 during the 8 school hours in the first intervention day was associated with an average of 1.76% (95% confidence interval (CI) 0.43-3.08%) increase in saliva lysozyme. This percentage increased to 2.41% (95%CI 0.52-4.26%) if related to the PM 2.5 level in 16 school hours over 2 days of intervention. A total of 19 nasal bacterial taxa were lower in subjects exposed to FAVS-HEPA, compared to that with no use of FAVS-HEPA, despite the general bacteria diversity levels in nasal samples were not statistically different. Among others, Providencia species showed significant effects in mediating the associations between higher PM 2.5 and lower lysozyme. In conclusion, using FAVS-HEPA was effective in decreasing the classroom indoor PM 2.5 . Saliva lysozyme, as a non-specific immune biomarker, was significantly inversely associated with indoor PM 2.5 . Certain nasal bacteria might play key roles in mediating PM 2.5 exposure and children's lysozyme levels., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Combined atmospheric oxidant capacity (O x ), represented by the sum of nitrogen dioxide (NO 2 ) and ozone (O 3 ), is an important hazardous property of outdoor air pollution mixture. It remains unknown whether its adverse effects can be ameliorated by dietary fish-oil supplementation., Objective: To assess the effects of fish-oil supplementation against oxidative stress induced by acute O x exposure., Methods: We conducted a randomized, double-blinded and placebo-controlled study among 65 young adults in Shanghai, China between September 2017 and January 2018. We randomly assigned participants to receive either 2.5 g/day of fish oil or placebo, and conducted four repeated physical examinations during the last two months of treatments. O x concentrations were calculated as the sum of hourly measurements of NO 2 and O 3 . We measured six biomarkers on systemic oxidative stress and antioxidant activity. Linear mixed-effect models were used to assess the short-term effects of O x on biomarkers in each group., Results: During our study period, the 72-h average O x concentration was 93.6 μg/m 3 . Short-term exposure to O x led to weaker changes in all biomarkers in the fish oil group than in the placebo group. Compared with the placebo group, for a 10-μg/m 3 increase in O x , there were smaller decrements in myeloperoxidase (MPO, difference = 5.92%, lag = 0-2 d, p = 0.03) and malondialdehyde (MDA, difference = 5.00%, lag = 1 d, p = 0.04) in the fish-oil group; there were also larger increments in total antioxidant capacity (TAC, difference = 16.33%, lag = 2 d, p = 0.02) and in glutathione peroxidase (GSH-Px, difference = 8.89%, lag = 0-2 d, p = 0.03) in the fish-oil group. The estimated differences for MPO were robust to adjustment for all co-pollutants and the differences for other biomarkers remained for some co-pollutants., Conclusions: This trial provides first-hand evidence that dietary fish-oil supplementation may alleviate the systemic oxidative stress induced by O x ., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Few epidemiological studies have evaluated the respiratory effects of personal exposure to nitrogen dioxide (NO 2 ), a major traffic-related air pollutant. The biological pathway for these effects remains unknown., Objectives: To evaluate the short-term effects of personal NO 2 exposure on lung function, fractional exhaled nitric oxide (FeNO) and DNA methylation of genes involved., Methods: We conducted a longitudinal panel study among 40 college students with four repeated measurements in Shanghai from May to October in 2016. We measured DNA methylation of the key encoding genes of inducible nitric oxide synthase (NOS2A) and arginase (ARG2). We applied linear mixed-effect models to assess the effects of NO 2 on respiratory outcomes., Results: Personal exposure to NO 2 was 27.39 ± 23.20 ppb on average. In response to a 10-ppb increase in NO 2 exposure, NOS2A methylation (%5 mC) decreased 0.19 at lag 0 d, ARG2 methylation (%5 mC) increased 0.21 and FeNO levels increased 2.82% at lag 1 d; and at lag 2 d the percentage of forced vital capacity, forced expiratory volume in 1 s and peak expiratory flow in predicted values decreased 0.12, 0.37 and 0.67, respectively. The model performance was better compared with those estimated using fixed-site measurements. These effects were robust to the adjustment for co-pollutants and weather conditions., Conclusions: Our study suggests that short-term personal exposure to NO 2 is associated with NOS2A hypomethylation, ARG2 hypermethylation, respiratory inflammation and lung function impairment. The use of personal measurements may better predict the respiratory effects of NO 2 ., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Fine particulate matter (PM 2.5 ) has been widely associated with airway inflammation represented by increased fractional concentration of exhaled nitric oxide (FeNO). However, it remains unclear whether various PM 2.5 constituents have different impacts on FeNO and its production process from the arginase (ARG)-nitric oxide synthase (NOS) pathway., Objectives: To investigate the acute effects of PM 2.5 constituents on FeNO and DNA methylation of genes involved., Methods: We conducted a longitudinal panel study among 43 young adults in Shanghai, China from May to October in 2016. We monitored the concentrations of 25 constituents of PM 2.5 . We applied the linear mixed-effect model to evaluate the associations of PM 2.5 constituents with FeNO and DNA methylation of the ARG2 and NOS2A genes., Results: Following PM 2.5 exposure, NOS2A methylation decreased and ARG2 methylation increased only on the concurrent day, whereas FeNO increased most prominently on the second day. Nine constituents (OC, EC, K, Fe, Zn, Ba, Cr, Se, and Pb) showed consistent associations with elevated FeNO and decreased NOS2A methylation or increased ARG2 methylation in single-constituent models and models adjusting for PM 2.5 total mass and collinearity. An interquartile range increase of these constituents was associated with respective decrements of 0.27-1.20 in NOS2A methylation (%5mC); increments of 0.48-1.56 in ARG2 methylation (%5mC); and increments of 7.12%-17.54% in FeNO., Conclusions: Our results suggested that OC, EC, and some metallic elements may be mainly responsible for the development and epigenetic regulation of airway inflammatory response induced by short-term PM 2.5 exposure., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Few studies have evaluated the health benefits of omega-3 fatty acid supplementation against fine particulate matter (aerodynamic diameter <2.5 μm [PM 2.5 ]) exposure in highly polluted areas., Objectives: The authors sought to evaluate whether dietary fish-oil supplementation protects cardiovascular health against PM 2.5 exposure in China., Methods: This is a randomized, double-blinded, and placebo-controlled trial among 65 healthy college students in Shanghai, China. Participants were randomly assigned to either the placebo group or the intervention group with dietary fish-oil supplementation of 2.5 g/day from September 2017 to January 2018, and received 4 rounds of health examinations in the last 2 months of treatments. Fixed-site PM 2.5 concentrations on campus were measured in real time. The authors measured blood pressure and 18 biomarkers of systematic inflammation, coagulation, endothelial function, oxidative stress, antioxidant activity, cardiometabolism, and neuroendocrine stress response. Acute effects of PM 2.5 on these outcomes were evaluated within each group using linear mixed-effect models., Results: The average PM 2.5 level was 38 μg/m 3 during the study period. Compared with the placebo group, the fish-oil group showed relatively stable levels of most biomarkers in response to changes in PM 2.5 exposure. Between-group differences associated with PM 2.5 exposure varied by biomarkers and by lags of exposure. The authors observed beneficial effects of fish-oil supplementation on 5 biomarkers of blood inflammation, coagulation, endothelial function, oxidative stress, and neuroendocrine stress response in the fish-oil group at a false discovery rate of <0.05., Conclusions: This trial shows that omega-3 fatty acid supplementation is associated with short-term subclinical cardiovascular benefits against PM 2.5 exposure among healthy young adults in China. (Effect of Dietary Supplemental Fish Oil in Alleviating Health Hazards Associated With Air Pollution; NCT03255187)., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

The C-terminally truncated Y145Stop variant of prion protein (PrP23-144), which is associated with heritable PrP cerebral amyloid angiopathy in humans and also capable of triggering a transmissible prion disease in mice, serves as a useful in vitro model for investigating the molecular and structural basis of amyloid strains and cross-seeding specificities. Here, we determine the protein-solvent interfaces in human PrP23-144 amyloid fibrils generated from recombinant 13 C, 15 N-enriched protein and incubated in aqueous solution containing paramagnetic Cu(II)-EDTA, by measuring residue-specific 15 N longitudinal paramagnetic relaxation enhancements using two-dimensional magic-angle spinning solid-state NMR spectroscopy. To further probe the interactions of the amyloid core residues with solvent molecules we perform complementary measurements of amide hydrogen/deuterium exchange detected by solid-state NMR and solution NMR methods. The solvent accessibility data are evaluated in the context of the structural model for human PrP23-144 amyloid., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Short-term exposure to ambient ozone is associated with adverse cardiovascular effects, with inconsistent evidence on the molecular mechanisms. We conducted a longitudinal panel study among 43 college students in Shanghai to explore the effects of personal ozone exposure on blood pressure (BP), vascular endothelial function, and the potential molecular mechanisms. We measured real-time personal ozone exposure levels, serum angiotensin-converting enzyme (ACE) and endothelin-1 (ET-1), and locus-specific DNA methylation of ACE and EDN1 (coding ET-1). We used an untargeted metabolomic approach to explore potentially important metabolites. We applied linear mixed-effect models to examine the effects of ozone on the above biomarkers. An increase in 2 h-average ozone exposure was significantly associated with elevated levels of BP, ACE, and ET-1. ACE and EDN1 methylation decreased with ozone exposure, but the magnitude differed by genomic loci. Metabolomics analysis showed significant changes in serum lipid metabolites following ozone exposure that are involved in maintaining vascular endothelial function. Our findings suggested that acute exposure to ambient ozone can elevate serum levels of ACE and ET-1, decrease their DNA methylation, and alter the lipid metabolism, which may be partly responsible for the effects of ozone on BP and vascular endothelial function.

Application of paramagnetic solid-state NMR to amyloids is demonstrated, using Y145Stop human prion protein modified with nitroxide spin-label or EDTA-Cu 2+ tags as a model. By using sample preparation protocols based on seeding with preformed fibrils, we show that paramagnetic protein analogs can be induced into adopting the wild-type amyloid structure. Measurements of residue-specific intramolecular and intermolecular paramagnetic relaxation enhancements enable determination of protein fold within the fibril core and protofilament assembly. These methods are expected to be widely applicable to other amyloids and protein assemblies.

Fine particulate matter (PM 2.5 ) has recently been associated with the activation of the hypothalamus-pituitary-adrenal (HPA) axis, increasing cardiometabolic risks. However, it is unknown which constituents of PM 2.5 were mainly responsible for these associations. In a longitudinal panel study with 4 repeated measurements among 43 college students in Shanghai, China, we measured serum levels of corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol, as indicators of HPA axis activation. Then, we evaluated the associations of 22 constituents of PM 2.5 with these stress hormones using linear mixed-effect models. During the study period, the average daily concentration of PM 2.5 was 41.1 μg/m 3 . We found that short-term exposure to PM 2.5 was associated with elevated levels of the 3 stress hormones. We observed that water-soluble inorganic ions, especially nitrate (NO 3 - ) and ammonium, had stronger influences on 3 hormones. Six metallic elements, including Zn, Mn, Cu, Fe, Br, and Cr, had positive but generally instable associations with 3 hormones. The effects of organic carbon and elemental carbon on hormones were generally weak. When correcting for multiple comparisons using false discovery rate, NO 3 - was still significantly associated with CRH, but other important associations turned to be insignificant. An interquartile range increase in NO 3 - on the previous day were associated with 12.13% increase (95% confidence interval: 4.45%, 20.37%) in CRH. Our findings suggested that water-soluble inorganic constituents of PM 2.5 (especially, NO 3 - ) might have stronger influences on the activation of HPA axis than carbonaceous and elemental components., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Epidemiologic studies of PM 2.5 (particulate matter with aerodynamic diameter ≤2.5 μm) and black carbon (BC) typically use ambient measurements as exposure proxies given that individual measurement is infeasible among large populations. Failure to account for variation in exposure will bias epidemiologic study results. The ability of ambient measurement as a proxy of exposure in regions with heavy pollution is untested., Objective: We aimed to investigate effects of potential determinants and to estimate PM 2.5 and BC exposure by a modeling approach., Methods: We collected 417 24 h personal PM 2.5 and 130 72 h personal BC measurements from a panel of 36 nonsmoking college students in Shanghai, China. Each participant underwent 4 rounds of three consecutive 24-h sampling sessions through December 2014 to July 2015. We applied backwards regression to construct mixed effect models incorporating all accessible variables of ambient pollution, climate and time-location information for exposure prediction. All models were evaluated by marginal R 2 and root mean square error (RMSE) from a leave-one-out-cross-validation (LOOCV) and a 10-fold cross-validation (10-fold CV)., Results: Personal PM 2.5 was 47.6% lower than ambient level, with mean (±Standard Deviation, SD) level of 39.9 (±32.1) μg/m 3 ; whereas personal BC (6.1 (±2.8) μg/m 3 ) was about one-fold higher than the corresponding ambient concentrations. Ambient levels were the most significant determinants of PM 2.5 and BC exposure. Meteorological and season indicators were also important predictors. Our final models predicted 75% of the variance in 24 h personal PM 2.5 and 72 h personal BC. LOOCV analysis showed an R 2 (RMSE) of 0.73 (0.40) for PM 2.5 and 0.66 (0.27) for BC. Ten-fold CV analysis showed a R 2 (RMSE) of 0.73 (0.41) for PM 2.5 and 0.68 (0.26) for BC., Conclusion: We used readily accessible data and established intuitive models that can predict PM 2.5 and BC exposure. This modeling approach can be a feasible solution for PM exposure estimation in epidemiological studies., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Little is known regarding the molecular mechanisms behind respiratory inflammatory response induced by ozone. We performed a longitudinal panel study with four repeated measurements among 43 young adults in Shanghai, China from May to October in 2016. We collected buccal samples and measured the fractional exhaled nitric oxide (FeNO) after 3-day personal ozone monitoring. In buccal samples, we measured concentrations of inducible nitric oxide synthase (iNOS) and arginase (ARG), and DNA methylation of NOS2A and ARG2. We used linear mixed-effect models to analyze the effects of ozone on FeNO, two enzymes and their DNA methylation. A 10 ppb increase in ozone (lag 0-8 h) was significantly associated with a 3.89% increase in FeNO, a 36.33% increase in iNOS, and a decrease of 0.36 in the average methylation (%5mC) of NOS2A. Ozone was associated with decreased ARG and elevated ARG2 methylation, but the associations were not significant. These effects were more pronounced among allergic subjects than healthy subjects. The effects were much stronger when using personal exposure monitoring than fixed-site measurements. Our study demonstrated that personal short-term exposure to ozone may result in acute respiratory inflammation, which may be mainly modulated by NOS2A hypomethylation in the arginase-nitric oxide synthase pathway.

Evidence is limited regarding whether ambient monitoring can properly represent personal ozone exposure. We conducted a longitudinal panel study to measure personal exposure to ozone using real-time personal ozone monitors. Corresponding ambient ozone concentrations and possible influencing factors (meteorological conditions and activity patterns) were also collected. We used linear mixed-effect models to analyze personal-ambient ozone concentration associations and possible influencing factors. Ambient ozone concentrations were around two to three times higher than personal ozone (43.1 μg/m 3 on average) and their correlations were weak with small slopes (0.35) and marginal R square (R M 2 ) values (0.24). Larger R M 2 values were found under high temperature (>29.5 °C), low humidity (<62.1%), good ventilation conditions (>4 h) and for individuals spent longer time outdoors (>0.6 h). In final model, personal ozone exposure was positively associated with ambient concentrations and ventilation conditions, but inversely correlated with ambient temperature and humidity. The models explained >50% of personal ozone concentration variabilities. Our results highlight that ambient ozone concentration alone is not a suitable surrogate for individual exposure assessment. Meteorological conditions (temperature and humidity) and activity patterns (windows opening and outdoor activities) that affecting personal ozone exposure should be taken into account., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Air pollution may increase cardiovascular and respiratory risk through inflammatory pathways, but evidence for acute effects has been weak and indirect. Between December 2014 and July 2015, we enrolled 36 healthy, nonsmoking college students for a panel study in Shanghai, China, a city with highly variable levels of air pollution. We measured personal exposure to particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5) continuously for 72 hours preceding each of 4 clinical visits that included phlebotomy. We measured 4 inflammation proteins and DNA methylation at nearby regulatory cytosine-phosphate-guanine (CpG) loci. We applied linear mixed-effect models to examine associations over various lag times. When results suggested mediation, we evaluated methylation as mediator. Increased PM2.5 concentration was positively associated with all 4 inflammation proteins and negatively associated with DNA methylation at regulatory loci for tumor necrosis factor alpha (TNF-α) and soluble intercellular adhesion molecule-1. A 10-μg/m3 increase in average PM2.5 during the 24 hours preceding blood draw corresponded to a 4.4% increase in TNF-α and a statistically significant decrease in methylation at one of the two studied candidate CpG loci for TNF-α. Epigenetics may play an important role in mediating effects of PM2.5 on inflammatory pathways.

Background: The underlying mechanisms about the association between ambient fine particulate matter (PM 2.5 ) and lung function were unclear. Few epidemiological studies have evaluated the potential mediating effects of serum club cell secretory protein (Clara) (CC16), a biomarker of pulmonary epithelium integrity., Objectives: To evaluate the short-term effect of personal PM 2.5 exposure on lung function and to explore the potential mediating role of CC16 in this effect., Methods: We enrolled 36 healthy, nonsmoking college students for a panel study in Shanghai, China from December 17, 2014 to July 11, 2015. We measured personal and real-time exposure to PM 2.5 for 72 h preceding each of four rounds of health examinations, including lung function test and serum CC16 measurement. We used linear mixed-effect models to examine the effects of PM 2.5 on lung function and CC16 over various lag times. Furthermore, we analyzed the mediating effect of CC16 in the association between PM 2.5 and lung function., Results: Average PM 2.5 exposure ranged from 36 to 52 μg/m3 across different lag periods. PM 2.5 exposure was negatively associated with lung function and positively associated with serum CC16 concentration. The effect of PM 2.5 on CC16 occurred earlier than that on lung function. For instance, an interquartile range (IQR) increase in 0-2 h average exposure to PM 2.5 was significantly associated with a 4.84% increase in serum CC16; and an IQR increase in 3-6 h average exposure to PM 2.5 was significantly associated with a 1.08% decrease in 1-sec forced expiratory volume. These effects lasted up to 24 h after exposure. Increased serum CC16 contributed 3.9%-36.3% of the association between PM 2.5 and impaired lung function., Conclusions: Acute exposure to PM 2.5 might induce an immediate decrease in lung function by virtue of the loss of pulmonary epithelium integrity., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Ambient fine particulate matter (PM2.5) air pollution has been associated with increased airway inflammation, but the roles of various PM2.5 constituents remain to be determined., Objectives: To investigate the acute effects of PM2.5 constituents on fractional exhaled nitric oxide (FeNO), a well-established biomarker of respiratory inflammation., Methods: A longitudinal panel study was performed among 32 healthy young adults in Shanghai, China from January 12th to February 6th, 2015. FeNO was repeatedly measured, 6-8 times per subject. Real-time mass concentration of ambient PM2.5 and chemical constituents were obtained from a nearby monitoring station. Linear mixed-effect models were applied to evaluate the association between FeNO and PM2.5 constituents, with the adjustment of age, gender, body mass index, temperature, relative humidity and day of week. The robustness of constituents' effects was also evaluated., Results: A total of 234 effective measurements of FeNO were obtained with a geometric mean of 13.1 ppb. The PM2.5-FeNO associations were strongest at lags of 0-6h and diminished at lags longer than 12h. An interquartile range increase in PM2.5 constituents (NH4(+), NO3(-), K(+), SO4(2-) and elemental carbon) at lags of 0-6h were significantly associated with increments in FeNO by 12.3%, 11.3%, 11.1%, 9.6% and 10.7%, respectively. After controlling for PM2.5 total mass and the colinearity, only elemental carbon remained significant., Conclusion: Several chemical constituents of PM2.5 may impact FeNO following acute exposure. Elemental carbon in particular may be the primary component responsible for increased airway inflammation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: The underlying intermediate mechanisms about the association between fine particulate matter (PM2.5) air pollution and blood pressure (BP) were unclear. Few epidemiological studies have explored the potential mediation effects of angiotensin-converting enzyme (ACE) and its DNA methylation., Methods: We designed a longitudinal panel study with 4 follow-ups among 36 healthy college students in Shanghai, China from December 17, 2014 to July 11, 2015. We measured personal real-time exposure to PM2.5, serum ACE level, and blood methylation of ACE gene and the repetitive elements. We applied linear mixed-effects models to examine the effects of PM2.5 on ACE protein, DNA methylation and BP markers. Furthermore, we conducted mediation analyses to evaluate the potential pathways., Results: An interquartile range increase (26.78μg/m(3)) in 24-h average exposure to PM2.5 was significantly associated with 1.12 decreases in ACE average methylation (%5mC), 13.27% increase in ACE protein, and increments of 1.13mmHg in systolic BP, 0.66mmHg in diastolic BP and 0.82mmHg in mean arterial pressure. ACE hypomethylation mediated 11.78% (P=0.03) of the elevated ACE protein by PM2.5. Increased ACE protein accounted for 3.90~13.44% (P=0.35~0.68) of the elevated BP by PM2.5. Repetitive-element methylation was also decreased but did not significantly mediate the association between PM2.5 and BP., Conclusions: This investigation provided strong evidence that short-term exposure to PM2.5 was significantly associated with BP, ACE protein and ACE methylation. Our findings highlighted a possible involvement of ACE and ACE methylation in the effects of PM2.5 on elevating BP., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Rhamnolipid acts as a virulence factor during Pseudomonas aeruginosa infection. Here, we show that deletion of the catabolite repression control (crc) gene in P. aeruginosa leads to a rhamnolipid-negative phenotype. This effect is mediated by the down-regulation of rhl quorum sensing (QS). We discover that a disruption of the gene encoding the Lon protease entirely offsets the effect of crc deletion on the production of both rhamnolipid and rhl QS signal C4-HSL. Crc is unable to bind lon mRNA in vitro in the absence of the RNA chaperon Hfq, while Crc contributes to Hfq-mediated repression of the lon gene expression at a posttranscriptional level. Deletion of crc, which results in up-regulation of lon, significantly reduces the in vivo stability and abundance of the RhlI protein that synthesizes C4-HSL, causing the attenuation of rhl QS. Lon is also capable of degrading the RhlI protein in vitro. In addition, constitutive expression of rhlI suppresses the defects of the crc deletion mutant in rhamnolipid, C4-HSL and virulence on lettuce leaves. This study therefore uncovers a novel posttranscriptional regulatory cascade, Crc-Hfq/Lon/RhlI, for the regulation of rhamnolipid production and rhl QS in P. aeruginosa., (© 2015 John Wiley & Sons Ltd.)

Background: Short-term associations between size-fractionated particulate air pollution and circulating biomarkers are not well established, especially in developing countries with high levels of particulate matter (PM)., Methods: We designed a panel study involving 34 healthy young adults to evaluate acute effects of size-fractionated PM on 13 circulating biomarkers of inflammation, coagulation, and vasoconstriction. We measured real-time, size-fractionated number concentrations of PM (aerodynamic diameters from 0.25 to 10 μm, mass concentrations of PM < 10 μm) over four follow-up measurements. The short-term associations between size-fractionated PM and biomarkers were assessed using linear mixed effect models., Results: We found positive associations between short-term exposure to PM and 10 biomarkers. PM with smaller size had stronger associations. The size fractions with the strongest associations were 0.25-0.40 μm for number concentrations and <1 μm for mass concentrations. For example, an interquartile range increase in 24-hour-average number concentrations of PM0.25-0.40 was associated with a 7%-32% increase in biomarkers of inflammation, 34%-68% of blood coagulation, and 45% of vasoconstriction. Similar estimates were found for mass concentrations of PM1. Furthermore, our results demonstrated an apparent acute effect on circulating biomarkers, even 2 hours after exposure. The effects were strongest within the first 12-24 hours, and effects on inflammation occurred more quickly than on coagulation and vasoconstriction., Conclusions: Our results provided potentially vital insights into the size and temporal characteristics of PM that could modify subclinical cardiovascular effects. These findings may have implications on disease prevention and environmental regulation in China.

Systemic infections by avian pathogenic Escherichia coli (APEC) are economically devastating to poultry industries worldwide. IbeR, located on genomic island GimA, was shown to serve as an RpoS-like regulator in rpoS gene mutation neonatal meningitis E. coli (NMEC) RS218. However, the role of IbeR in pathogenicity of APEC carrying active RpoS has not yet been investigated. We showed that the APEC IbeR could elicit antibodies in infected ducks, suggesting that IbeR might be involved in APEC pathogenicity. To investigate the function of IbeR in APEC pathogenesis, mutant and complementation strains were constructed and characterized. Inactivation of ibeR led to attenuated virulence and reduced invasion capacity towards DF-1 cells, brains and cerebrospinal fluid (CSF) in vitro and in vivo. Bactericidal assays demonstrated that the mutant strain had impaired resistance to environmental stress and specific pathogen-free (SPF) chicken serum. These virulence-related phenotypes were restored by genetic complementation. Quantitative real-time reverse transcription PCR revealed that IbeR controlled expression of stress-resistance genes and virulence genes, which might led to the associated virulence phenotype.

Context: Several previous studies proposed a link between particulate matter (PM) pollution and mitochondrial DNA copy number (MtDNAcn) and telomere length (TL). However, this evidence is quite limited and inconsistent, especially on how the particle size affects the associations and on whether there exists such an association with gaseous pollutants., Objective: We aimed to investigate the short-term associations of size-fractionated PM and gaseous pollutants with blood MtDNAcn and TL., Methods: We conducted a longitudinal panel study involving 6 repeated measurements among 35 Type 2 diabetes patients in Shanghai, China from April to June 2013. We measured the real-time concentrations of size-fractionated PM (0.25-10 μm) and criteria gaseous pollutants. Blood MtDNAcn and TL were tested by a quantitative real-time PCR-based assay. Linear mixed-effect models were used to explore their short-term associations using multiple lag periods, after controlling for individual characteristics, time trends and weather conditions., Results: In general, there were inverse but statistically non-significant associations between all pollutants and MtDNAcn. Coarse PM appeared to be more closely linked with MtDNAcn than smaller PM. The associations between various air pollutants and TL were generally positive but very weak. There were no clear lag patterns for these associations. The associations between air pollutants and MtDNAcn and TL were strengthened but still not significant among those who did not take statins regularly., Conclusions: This study did not support short-term associations of PM or gaseous pollutants with blood MtDNAcn and TL in type 2 diabetes patients.

The rhl quorum-sensing (QS) system plays critical roles in the pathogenesis of P. aeruginosa. However, the regulatory effects that occur directly upstream of the rhl QS system are poorly understood. Here, we show that deletion of gene encoding for the two-component sensor BfmS leads to the activation of its cognate response regulator BfmR, which in turn directly binds to the promoter and decreases the expression of the rhlR gene that encodes the QS regulator RhlR, causing the inhibition of the rhl QS system. In the absence of bfmS, the Acka-Pta pathway can modulate the regulatory activity of BfmR. In addition, BfmS tunes the expression of 202 genes that comprise 3.6% of the P. aeruginosa genome. We further demonstrate that deletion of bfmS causes substantially reduced virulence in lettuce leaf, reduced cytotoxicity, enhanced invasion, and reduced bacterial survival during acute mouse lung infection. Intriguingly, specific missense mutations, which occur naturally in the bfmS gene in P. aeruginosa cystic fibrosis (CF) isolates such as DK2 strains and RP73 strain, can produce BfmS variants (BfmSL181P, BfmSL181P/E376Q, and BfmSR393H) that no longer repress, but instead activate BfmR. As a result, BfmS variants, but not the wild-type BfmS, inhibit the rhl QS system. This study thus uncovers a previously unexplored signal transduction pathway, BfmS/BfmR/RhlR, for the regulation of rhl QS in P. aeruginosa. We propose that BfmRS TCS may have an important role in the regulation and evolution of P. aeruginosa virulence during chronic infection in CF lungs.

Objective: To construct and express the single chain variable fragment (scFv) against human CD86 in CHO cells, and observe its biological functions of binding with antigen., Methods: The V(H); and V(L); genes were cloned by RT-PCR from a murine hybridoma cell line 1D1, which produced the monoclonal antibody (mAb) against human CD86. The CD86-scFv gene was integrated into eukaryotic expression vector to construct pIREST2-EGFP/scFv. CHO cells were transfected by pIREST2-EGFP/scFv plasmid with Lipofectamine(TM); 2000 and then were selected by G418. We used IMAC affinity chromatography to purify CD86-scFv and quantified its concentration by BCA method. Then the identification of CD86-scFv binding to membrane CD86 was performed through competitive inhibition assay. In addition, the growth inhibition effect of CD86-scFv on Raji cells was detected via MTT assay., Results: One cell line stably expressing CD86-scFv was obtained. The CD86-scFv could identify CD86 molecules on L929-CD86, Raji and Daudi cells, and the positive rates were 67.0%, 72.3% and 80.5%, respectively. CD86-scFv showed the competitive binding to murine parent antibody 1D1. Moreover, CD86-scFv inhibited the growth of Raji cells and the inhibition rate was 28.3% 72 h after 20 μg/mL CD86-scFv was added into Raji cells., Conclusion: CD86-scFv has been successfully expressed in CHO cells (named SA-IV) and the antibody shows a good biological function of recognizing CD86 and inhibiting the growth of Raji cells.

The ibeB gene in neonatal meningitis Escherichia coli (NMEC) contribute to the penetration of human brain microvascular endothelial cells (HBMECs). However, whether IbeB plays a role in avian pathogenic E. coli (APEC) infection remains unclear. Thus, this study was conducted to investigate the distribution of the ibeB gene in Chinese APEC strains and examine whether IbeB is involved in APEC pathogenicity. The ibeB gene was found in all 100 detected E. coli isolates with over 97% sequence homology. These results indicated that ibeB is a conserved E. coli gene irrelevant of pathotypes. To determine the role of ibeB in APEC pathogenicity, an ibeB mutant of strain DE205B was constructed and characterized. The inactivation of ibeB resulted in reduced invasion capacity towards DF-1 cells and defective virulence in animal models as compared to the wild-type strain. Animal infection experiments revealed that loss of ibeB decreased APEC colonization and invasion capacity in brains and lungs. These virulence-related phenotypes were partially recoverable by genetic complementation. Reduced expression levels of invasion- and adhesion-associated genes in ibeB mutant could be major reasons as evidenced by reduced ibeA and ompA expression. These results indicate that IbeB is involved in APEC invasion and pathogenicity., (Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.)

Systemic infections in avian species caused by avian pathogenic Escherichia coli (APEC) are economically devastating to poultry industries worldwide. To unravel factors possibly involved in APEC pathogenicity, suppression subtractive hybridization was applied, leading to the identification of a putative APEC autotransporter adhesin gene aatA in our previous study. In this study, pathogenic mechanism of AatA was further determined. A deletion mutant of aatA was constructed in the APEC DE205B, which results in the reduced capacity to adhere to DF-1 cells, defective virulence in vivo, and decreased colonization capacity in lung during the systemic infection compared with the wild-type strain. Furthermore, these capacities were restored in the complementation strains. These results indicated that AatA makes a significant contribution to APEC virulence through bacterial adherence to host tissues in vivo and in vitro. In addition, aggregation assays for strain AAEC189 expressing aatA indicated that AatA mediates cell aggregation and settling of cells. However, this cell aggregation is blocked by Type I fimbriae. This study illustrates the first examination of the role of AatA in aggregation and systemic infection., (© 2011 This article is a Chinese Government work and is in the public domain in China. Published by Blackwell Publishing Ltd.)

The ibeA gene is located on a genomic island, GimA, which is involved in the pathogenesis of neonatal meningitis Escherichia coli (NMEC) and avian pathogenic E. coli (APEC). The prevalence of ibeA in the APEC collection in China was investigated, and 20 of 467 strains (4.3%) were positive. In addition, analysis of the association of the E. coli reference (ECOR) groups with positive strains revealed that ibeA was linked to group B2. The ibeA gene in DE205B was analyzed and compared to those of APEC and NMEC, which indicated that the specificity of ibeA was not consistent along pathotypes. The invasion of chicken embryo fibroblast DF-1 cells by APEC DE205B and RS218 was observed, which suggested that DF-1 cells could be a model to study the mechanism of APEC invasion. The inactivation of ibeA in APEC DE205B led to the reduced capacity to invade DF-1 cells, defective virulence in vivo, and decreased biofilm formation compared to the wild-type strain. In addition, strain AAEC189 expressing ibeA exhibited enhanced invasion capacity and biofilm formation. The results of the quantitative real-time reverse transcription-PCR (qRT-PCR) analysis and animal system infection experiments indicated that the loss of ibeA decreased the colonization and proliferation capacities of APEC in the brain during system infection.