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The CpG island of GADD45G was identified as a target sequence during the identification of hypermethylated genes using methylation-sensitive representational difference analysis combined with 5-aza-2V -deoxycytidine demethylation. Located at the commonly deleted region 9q22, GADD45G is a member of the DNA damage-inducible gene family. In response to stress shock, GADD45G inhibits cell growth and induces apoptosis. Same as other GADD45 members, GADD45G is ubiquitously expressed in all normal adult and fetal tissues. However, its transcriptional silencing or down-regulation and promoter hypermethylation were frequently detected in tumor cell lines, including 11 of 13 (85%) non-Hodgkin's lymphoma, 3 of 6 (50%) Hodgkin's lymphoma, 8 of 11 (73%) nasopharyngeal carcinoma, 2 of 4 (50%) cervical carcinoma, 5 of 17 (29%) esophageal carcinoma, and 2 of 5 (40%) lung carcinoma and other cell lines but not in any immortalized normal epithelial cell line, normal tissue, or peripheral blood mononuclear cells. The silencing of GADD45G could be reversed by 5-aza-2V -deoxycytidine or genetic double knockout of DNMT1 and DNMT3B, indicating a direct epigenetic mechanism. Aberrant methylation was further frequently detected in primary lymphomas although less frequently in primary carcinomas. Only one single sequence change in the coding region was detected in 1 of 25 cell lines examined, indicating that genetic inactivation of GADD45G is very rare. GADD45G could be induced by heat shock or UV irradiation in unmethylated cell lines; however, this stress response was abolished when its promoter becomes hypermethylated. Ectopic expression of GADD45G strongly suppressed tumor cell growth and colony formation in silenced cell lines. These results show that GADD45G can act as a functional new-age tumor suppressor but being frequently inactivated epigenetically in multiple tumors.

BackgroundThe recovery of diaphragmatic function is vital for successful extubation from mechanical ventilation. Recent studies have detected diaphragm atrophy in ventilated adults by using ultrasound, but no similar report has been conducted in children. In the current study, we hypothesized that mechanically ventilated children may also develop diaphragm atrophy and diaphragmatic dysfunction.Materials and methodsChildren who were admitted to the pediatric intensive care unit and were newly intubated for mechanical ventilation were enrolled into this prospective case–control study. Diaphragm ultrasound assessments were performed daily to evaluate diaphragmatic function in the enrolled children until their discharge from the pediatric intensive care unit. Diaphragm thickness and the diaphragmatic thickening fraction (DTF) were measured through these assessments.ResultsA total of 31 patients were enrolled, and overall, 1389 ultrasound assessments were performed. Immediately after intubation, the initial diaphragm thickness and DTF were measured to be 1.94 ± 0.44 mm and 25.85% ± 3.29%, respectively. In the first 24 hours of mechanical ventilation, diaphragm thickness and the DTF decreased substantially and decreased gradually thereafter. After extubation, the DTF was significantly different between the successful and failed extubation groups (P < 0.001), and a DTF value of <17% was associated with extubation failure.ConclusionsDiaphragm ultrasound is a noninvasive method for measuring diaphragmatic function in mechanically ventilated children. In this study, significant diaphragm atrophy and a decreased DTF were observed within 24 hours of mechanical ventilation. The recovery of diaphragm thickness and the DTF may be a potential predictor of successful extubation from mechanical ventilation.

ObjectivesA detailed understanding of the metabolic processes governing rapid growth in early life is still lacking. The aim of this study was to investigate the age-related metabolic changes in healthy children throughout early childhood.MethodsHealthy children from a birth cohort were enrolled in this study from birth through 4 years of age. Urinary metabolites were assessed at 6 months, and 1, 2, 3, and 4 yr of age by using 1H-nuclear magnetic resonance (NMR) spectroscopy coupled with multivariate statistical analysis including principal components analysis (PCA) and partial least-squares discriminant analysis (PLS-DA). Metabolic pathway analysis was performed using the MetPA web tool.ResultsA total of 105 urine samples from 30 healthy children were collected and analyzed. Metabolites contributing to the discrimination between age groups were identified by using supervised PLS-DA (Q2 = 0.60; R2 = 0.66). A significantly higher urinary trimethylamine N-oxide (TMAO) and betaine level was found in children aged 6 months. Urinary glycine and glutamine levels declined significantly after 6 months of age and there was a concomitant compensatory increase in urinary creatine and creatinine. Metabolic pathway analysis using MetPA revealed similar nitrogen metabolism associated energy production across all ages assessed. Pathways associated with amino acid metabolism were significantly different between infants aged 6 months and 1 year, whereas pathways associated with carbohydrate metabolism were significantly different between children at ages 2 and 3 years.ConclusionsUrine metabolomics ideally represents dynamic metabolic changes across age. Urinary metabolic profiles change significantly within the first year of life, which can potentially provide crucial information about infant nutrition and growth.

Human metapneumovirus (HMPV) is a recently discovered pathogen that causes a significant proportion of respiratory infections in young infants, the elderly and immunocompromised patients. Very little is known regarding the cellular signalling elicited by this virus in airway epithelial cells, the target of HMPV infection. In this study, we investigated the role of the RNA helicases retinoic acid inducible gene-I (RIG-I) and melanoma differentiation-associated gene-5 (MDA-5) as the main pattern recognition receptors (PRRs) involved in viral detection and subsequent expression of proinflammatory and antiviral genes. HMPV infection readily induced RIG-I and MDA-5 gene and protein expression in A549 cells, a type II-like alveolar epithelial cell line. Expression of dominant-negative (DN) RIG-I or downregulation of RIG-I gene expression using small interfering RNA (siRNA) significantly decreased HMPV-induced beta interferon (IFN-b), interleukin (IL)-8 and RANTES gene transcription, by inhibiting viral-induced activation of nuclear factor (NF)-kB and interferon regulatory factor (IRF), leading to enhanced viral replication. On the other hand, MDA-5 did not seem to play a significant role in HMPV-induced cellular responses. Mitochondrial antiviral signalling protein (MAVS), an adaptor protein linking both RIG-I and MDA-5 to downstream activation of IRF-3 and NF-kB, was also necessary for HMPVinduced cellular signalling. Expression of a DN MAVS significantly reduced IFN-b and chemokine gene transcription, by inhibiting NF-kB-and IRF-dependent gene transcription, in response to HMPV infection. Our results show that HMPV activates the RIG-I-MAVS signalling pathway in airway epithelial cells, leading to the expression of important proinflammatory and antiviral molecules involved in the innate immune response to viruses. INTRODUCTIONHuman metapneumovirus (HMPV) is a recently identified respiratory RNA virus belonging to the family Paramyxoviridae. HMPV is responsible for a significant proportion of upper and lower respiratory tract infections in young children, the elderly and immunocompromised patients, causing bronchiolitis, croup, asthma exacerbation and even pneumonia (Boivin et al., 2002;Esper et al., 2003;Williams et al., 2004), second only to respiratory syncytial virus (RSV) (Kahn, 2006;Principi et al., 2006;Williams et al., 2004), also a paramyxovirus. While there is emerging literature on the clinical and epidemiological features of HMPV infection, very little is known regarding the cellular signalling activated by this pathogen in infected cells. We have recently demonstrated that HMPV is a potent stimulus for cytokine, chemokine and type I interferon (IFN) production in cultured human alveolar epithelial cells, and that HMPV-induced chemokine expression is dependent on viral replication (Bao et al., 2007). We have also shown that HMPV infection induces activation of nuclear factor (NF)-kB and interferon regulatory factor (IRF) transcription factors (Bao et al., 2007), which have been shown to play a fundamental ...

BackgroundThe current literature focusing on the effect of obesity and overweight on lung function and fraction of exhaled nitric oxide (FeNO) in children, particularly among healthy children of non-European descent, remains controversial. Furthermore, whether the relationship of obesity and overweight with lung function and FeNO in children is modified by atopy is unclear. The objective of this study was to examine the effect of excess weight on lung function parameters and FeNO among Asian children, with a particular focus on exploring the potential effect modification by atopy.MethodsWe investigated the effect of excess weight on lung function and FeNO in a population sample of 1,717 children aged 5 to 18 years and explored the potential modifying effect of atopy.ResultsThere were positive associations of body mass index (BMI) z-score with forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow (PEF), and forced expiratory flow at 25–75% (FEF25-75) (all P<0.001), after controlling for confounders. The beta coefficient for FEV1 (0.084) was smaller than that for FVC (0.111). In contrast, a negative association was found between BMI z-score and FEV1/FVC ratio (P<0.001) and FeNO (P = 0.03). A consistent pattern of association for lung function variables was observed when stratifying by atopy. There was a negative association of BMI z-score with FeNO in atopic subjects (P = 0.006), but not in non-atopic subjects (P = 0.46).ConclusionsExcess weight disproportionately impacts lung volumes and airflow in children from the general population, independent of atopic status. Excess weight inversely affects FeNO in atopic but not in non-atopic children.

The ease of obtaining fetal-type MSCs and their rapid proliferation make these cells ideal candidates for cell-based therapies, especially for diseases associated with immune responses, given the immunosuppressive effects of these cells. IL-6 might play an important role in the immunosuppressive effects of various stem cells.

BackgroundLung ultrasonography has been advocated in diagnosing pediatric community-acquired pneumonia. However, its function in identifying necrotizing pneumonia, a complication, has not been explored. This study investigated the value of lung ultrasonography in diagnosing pediatric necrotizing pneumonia and its role in predicting clinical outcomes.MethodsWe retrospectively reviewed 236 children with community-acquired pneumonia who were evaluated using lung ultrasonography within 2–3 days after admission. The ultrasonographic features assessed included lung perfusion, the presence of hypoechoic lesions, and the amount of pleural effusion. Chest computed tomography was also performed in 96 patients as clinically indicated. Detailed records of clinical information were obtained.ResultsOur results showed a high correlation between the degree of impaired perfusion in ultrasonography and the severity of necrosis in computed tomography (r = 0.704). The degree of impaired perfusion can favorably be used to predict massive necrosis in computed tomography (area under the receiver operating characteristic curve, 0.908). The characteristics of impaired perfusion and hypoechoic lesions in ultrasonography were associated with an increased risk of pneumatocele formation (odds ratio (OR), 10.11; 95% CI, 2.95–34.64) and the subsequent requirement for surgical lung resection (OR, 8.28; 95% CI, 1.86–36.93). Furthermore, a longer hospital stay would be expected if moderate-to-massive pleural effusion was observed in addition to impaired perfusion in ultrasonography (OR, 3.08; 95% CI, 1.15–8.29).ConclusionLung ultrasonography is favorably correlated with chest computed tomography in the diagnosis of necrotizing pneumonia, especially regarding massive necrosis of the lung. Because it is a simple and reliable imaging tool that is valuable in predicting clinical outcomes, we suggest that ultrasonography be applied as a surrogate for computed tomography for the early detection of severe necrotizing pneumonia in children.