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OBJECTIVE: To analyze the effects of severe neonatal asphyxia on various organ-systems and to identify the risk factors associated with the resultant injuries and death. METHODS: The data of 170 cases in the last 10 years from January 1993 to March 2004 were analyzed. The risk factors associated with death were subjected to odds ratio (OR) analysis with the SAS software. RESULTS: There were 22 deaths in the 170 cases (12.5%). Organ-system injuries were evident in 165 of 170 cases (97.1%). In descending orders, the organ-system injuries were central nervous system [CNS,66.5%(113/170)], pulmonary [62.9%(107/170)] and metabolic disorders [50.6%(86/170)]. The severity of injuries was in the reversed orders from metabolic disorders, pulmonary to CNS. From high risk to low, the factors which affected the mortality of severe asphyxia were, in order, severe CNS injury, ≥1 organ/system injury, respiratory failure, metabolic abnormality, electrolyte imbalance, blood-gas abnormality, pulmonary involvement, 10 min Apgar score≤3, gestational age<37 weeks, hepatic involvement, cardiac involvement, raised PCO_2, and hematologic involvement. CONCLUSIONS: Organ-system injuries in addition to hypoxic-ischemic encephalopathy (HIE) were complications found in the majority of the cases with severe neonatal asphyxia. The risk factors such as CNS injury or HIE, pulmonary dysfunction and failure, and multiorgan dysfunction syndrome (MODS) involving more than three organ-systems should be detected and recognized early so that early intervention can be instituted to reduce the mortality

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OBJECTIVE: Many studies have demonstrated that neurogenesis is enhanced after cerebral ischemia in the adult rats. However, little is known about neurogenesis in the brain of neonatal rats after hypoxia-ischemia (HI). This study investigated neurogenesis in neonatal rats 1 and 4 weeks after HI. METHODS: Twenty-four seven-day-old Wistar rats were randomly assigned into Control group (n=8) and Experimental group (n=16). HI was induced by ligating the right common carotid artery combined with hypoxia exposure (8% oxygen in nitrogen) in the Experimental group. In the Control group, the right common carotid artery was isolated but not ligated and there was no exposure to hypoxia. MR imaging was performed 24 hrs after HI to confirm the formation of infarct. Bromodeoxyuridine (BrdU) was injected intraperitonally daily between 2-6 days after operation or HI to label newly generated cells in both groups. Neurogenesis was examined by immunofluorescence assay 1 and 4 weeks after HI. RESULTS: Subventricular zone (SVZ) was obviously enlarged in the ischemic hemisphere but not in the contralateral hemisphere in the Experimental group 1 or 4 weeks after HI. The number of BrdU positive cells in the SVZ of the ischemic hemisphere in the Experimental group increased significantly compared with that in the Control group or that in the contralateral hemisphere 1 week after HI (both P< 0.05). After 4 weeks of HI the number of BrdU positive cells in the ischemic hemisphere decreased compared with that 1 week after HI, but still remained significantly higher than that in the Control group (P<0.05). The number of BrdU positive cells in the subgranular zone (SGZ) of the ischemic hemisphere increased 1 week after HI, being significantly higher than that in the Control group (P<0.05). After 4 weeks of HI the number of BrdU positive cells in the SGZ of the ischemic hemisphere decreased compared with that 1 week after HI, but still was significantly higher than that in the Control group (P<0.05). Some scattered BrdU positive cells were observed in the striatum or cortex of the ischemic hemisphere, particularly in peri-infarct 1 or 4 weeks after HI. CONCLUSIONS: Similar to the brain of adult rats, neurogenesis is enhanced in the brain of neonatal rats following HI. This result suggests that immature brain may have the capacity for self-repair.

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Children have the highest prevalence of asthma, an obstructive lung disease characterized by bronchoconstriction, persistent airway inflammation and airway remodeling. Inhaled corticosteroids and β2-agonists add-on therapies are used to treat these children but these medications are not always effective, and inappropriately high doses of corticosteroid may lead to serious side effects such as osteoporosis, growth retardation, and glaucoma. Oral anti-leukotrienes are new treatments for children suffering from asthma that work by antagonizing leukotrienes and inhibiting their synthesis. Leukotrienes are lipids synthesized from arachidonic acids in the 5-lipoxygenase pathway by mast cells, eosinophils, and alveolar macrophages in the lungs. Leukotrienes are involved in the asthmatic response by binding to the CysLT1 receptor on the airway smooth muscles, causing bronchoconstriction. Recent studies have shown that the cysteinyl-leukotrienes may mediate subepithelial collagen deposition and smooth muscle hypertrophy and hyperplasia, causing irreversible airway remodeling and airway obstruction. Experimental studies and preliminary clinical reports on pediatric patients have shown that the leukotriene antagonist montelukast may prevent airway remodeling and reduce asthmatic symptoms when used as an add-on treatment to reduce the intake of corticosteroids and β2-agonists. However, the efficacy of anti-leukotrienes drugs still needs to be confirmed by randomized, double-blind and multicenter clinical trials.

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OBJECTIVE: DNA methylation has been regarded as an important genetics marker reflecting the transcription state of DNA in cells. This study aimed to assess the methylation of CpG island in 5' promotor region of p15 and p16 genes in children with hepatoblastoma, and to explore its relationship with the development of hepatoblastoma. METHODS: The methylation-specific polymerase chain reaction (MSP) and PCR-SSCP techniques were used to analyze DNA methylation. The tumor tissues, the tissues beside the tumor and normal tissues beyond the tumor in 30 cases with hepatoblastoma were studied by nested MSP. The target fragment was verified by gel electrophoresis and sequencing. RESULTS: The incidence of abnormal methylation of 5' CpG island of p15 and p16 genes in tumor tissues was 30% (9/30) and 67% (20/30) respectively. It was 20% (6/30) and 57% (17/30) respectively in the tissues beside tumor and that was 13% (4/30) and 33% (10/30) respectively in the normal tissues beyond the tumor. Homozygous deletion of exon 2 of p15 gene was found in 1 of 30 cases (3%) in hepatoblastoma. No deletion of exon 1 or intron 1 was found. Heterozygosis deletion of exon 2 of p16 gene and partial intron 2 was found in 3 of 30 cases (10%). No deletion of exon 1 or intron 1 was found. CONCLUSIONS: The abnormal methylation of CpG island in 5' promotor region of p15 and p16 genes appears to play a role in the development of hepatoblastoma, which might be attributed to the inhibition of gene transcription by abnormal methyaltion of CpG island in the promotor region.

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OBJECTIVE:  To introduce a simple, rapid and stable method for the determination of plasma acylation stimulating protein (ASP) and to explore the value of plasma ASP determination. METHODS: Sixty-three simple obese children and 98 healthy controls were included in this study. The ELISA technique was employed to determine the plasma ASP concentration. RESULTS: The best linearity of test was between 0.5-10 ng/mL. The intra-assay coefficient of variation (CV) was 8.17% and inter-assay CV, 9.72%. The average plasma ASP concentration in healthy children was 69.14±25.58 nM and 95.64±36.24 nM in obese children (P<0.001). Plasma ASP was positively correlated with body mass index in both healthy and obese children (r=0.2883 and 0.337, respectively, both P<0.01). CONCLUSIONS: Plasma ASP can be quantified by the ELISA method. Plasma ASP determination may be recommended as a new method for lipid metabolism determination in children.

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OBJECTIVE: The!aim of this study was to investigate the influence of caesarean section on early pulmonary function of the neonate by examining the tidal breathing parameters in neonates delivered by caesarean section and comparing them with the parameters of neonates delivered vaginally. METHODS: The subjects included 42 neonates delivered by caesarean section and 30 neonates delivered vaginally. Various pulmonary function parameters were assayed by the tidal breathing method within 1 hr after birth. The parameters included minute ventilation (MV), respiratory rate (RR), tidal volume (VT), inspiratory time (TI), expiratory time (TE), ratio Ti/Te (TI/TE), peak tidal expiratory flow (PTEF), time to PTEF (TPEF), ratio of TPEF and total TE (TPEF/TE), expiratory volume at PTEF (VPEF), ratio of VPEF and total VE (VPEF/VE), and TEF25%, TEF50% and TEF75% remaining (TEF25%, TEF50%, TEF75%). Tidal flow-volume (TFV) curves were also constructed. RESULTS: MV (1.16±0.31 L/min) and VT(4.81±1.05 mL/kg) in neonates delivered by caesarean section were remarkably lower than in those delivered vaginally (1.34±0.33 L/min and 5.55±1.24 mL/kg, respectively; P<0.05). The neonates delivered by caesarean section showed faster PTEF (69.40±21.96 mL/s vs 59.03±15.23 mL/s; P<0.05) and TEF25% (62.17±20.62 mL/s vs 51.52±13.83 mL/s; P< 0.05) compared with those delivered vaginally. TPEF/TE (66.08%±11.51%) and VPEF/VE (62.19%±8.69 %) in neonates delivered by caesarean section were significantly higher than in those delivered vaginally(60.36%±9.70% and 55.75%±7.28%, respectively; P<0.05). No statistical differences were found between the two groups for RR, TT, TE, TI/TE, TEF50% and TEF75%. TFV curves of both groups presented with slender and irregular ellipse in shape and peak value in expiratory flow appeared late . In neonates delivered by caesarean section, the TFV curve was narrower and peak value in expiratory flow was higher than in those delivered vaginally. CONCLUSIONS: VT and MV were lower and restrictive hypoventilation was more severe within 1 hr after birth in neonates delivered by caesarean section compared with those delivered vaginally.

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OBJECTIVE: Airway occlusion pressure at 0.1 sec (P_ 0.1) has been widely used in the assessment of respiratory function. This study aimed to assess the values of P_ 0.1 and end-expiratory CO_2 (PetCO_2) in pediatric patients with mechanical ventilation. METHODS: A total of 29 mechanical-ventilation children, aged ranging from 8 months to 16 years(average of 4.3 years), with non-pulmonary respiratory failure admitted to the intensive care unit were included in this study. P_ 0.1 and PetCO_2 were monitored during mechanical ventilation. RESULTS: P_ 0.1 obtained on the day of weaning from the respirator increased significantly compared with that on the first day in the 0- 1 years old group (1.8±0.25 cmH_2O vs 0.23±0.17 cmH_2O),the 1- 3 years old group (2.0±0.27 cmH_2O vs 0.13±0.10 cmH_2O ) and the 3-16 years old group ( 2.1±0.28 cmH_2O vs 0.30±0.17 cmH_2O) (P< 0.001). PetCO_2 positively correlated with PaCO_2 (r= 0.894, P< 0.001). CONCLUSIONS: Monitoring the changes of P_ 0.1 and PetCO_2 is useful in adjusting the parameters of the respirator during mechanical ventilation. P_ 0.1 may serve as a marker for weaning from mechanical ventilation.

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OBJECTIVE: To study the effect of lung protective strategies of ventilation on the term neonates with hypoxemic respiratory failure (HRF). METHODS: Fifty-three term neonates with HRF were randomly divided into two groups: lung protective ventilation (LPV) group (n=27) and conventional mechanical ventilation (CMV) group (n=26). The parameters of ventilation, results of blood-gas analysis, incidences of ventilator-associated lung injury, intraventicular hemorrhage (IVH) and patent ductus arteriosus (PDA), and mortality were compared. RESULTS: In the peak stage of HRF, peak inflation pressure (PIP) and mean airway pressure (MAP) were 2.50±0.28 and 1.04±0.25 kPa respectively in the LPV group, significantly lower than those in the CMV group (2.97±0.35 and 1.28±0.30 kPa, P<0.01). Positive end-expiratory pressure (PEEP) in the LPV group was significantly higher than that in the CMV group (0.61±0.08 kPa vs 0.53±0.09 kPa, P<0.01). There were no differences in fraction of inspired oxygen (FiO_2), inspiratory time (Ti) and ventilation rate between the two groups. The pH (7.29±0.10) in the LPV group was lower than that in the CMV group (7.38±0.12, P<0.01), but PaCO_2 (7.13±1.02 kPa) was higher than that in the CMV group (5.40±1.06 kPa, P<0.01). The PaO_2 and SaO_2 of the LPV group were not different from those of the CMV group. The LPV group showed lower incidence of air leak (4% vs 35%, P<0.01) and similar incidences of IVH, PDA and lung hemorrhage to the CMV group. LPV resulted in a decreased mortality compared with CMV (11%(3/27) vs 35%(9/26), P<0.05). CONCLUSIONS: Using lung protective strategies in mechanical ventilation can markedly reduce the incidence of air leak and mortality for neonates with HRF.

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OBJECTIVE: The probability of bronchial asthma following bronchiolitis caused by respiratory syncytial virus (RSV) is high. This paper determined the changes of T cell subgroups in infants with bronchiolitis caused by RSV so as to investigate the association between bronchiolitis caused by RSV and asthma. METHODS: T cell subgroups were detected by flow cytometry in 21 infants with RSV bronchiolitis (Study group, mean age 10 months) and 20 age-matched healthy children (Control group). RESULTS: There were no statistical differences in the levels of CD4 and CD8 between the two groups. However, the ratio of CD4/CD8 in the Study group was significantly higher than that in the Control group (1.56±0.22 vs 1.40±0.28, P<0.05). CONCLUSIONS: The ratio of CD4/CD8 in children with bronchiolitis caused by RSV is elevated. The change of T cell subgroups is similar to that of asthma.

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OBJECTIVE: Measurements of heart rate variability (HRV) are increasingly used as markers of cardiac autonomic activity. The aim of this study was to investigate the characteristics of HRV in children with palpitations of unknown causes so as to provide a basis for the etiologic diagnosis of palpitations. METHODS: Thirty-four children with palpitations of unknowns causes (Study group) and 27 aged-matched healthy children (Control group) were enrolled in this study. Three time domain indexes of HRV from 24-hr Holter monitoring (SDNN, RMSSD and PNN50) were analyzed. The changes of ST-T segment and the circadian variation of heart rate were examined. RESULTS: Three time domain indexes of HRV significantly decreased in the Study group compared with those of the Control group (P <0.05). Fifteen patients in the Study group showed ST-T segment changes, characterized by a descended ST segment and a low-flat T wave during daytime but the changes disappeared during sleep. The circadian changes of heart rate were also observed in the 15 patients. The change characteristics were consistent with the diagnostic criteria of beta-receptor hypersensitivity. CONCLUSIONS: Three time domain indexes of HRV decrease in children with palpitations of unknown causes. HRV analysis along with ST-T segment change characteristics appears to be helpful for the etiologic diagnosis of this disease.

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OBJECTIVE: Chronic gastritis and peptic ulcer are considered to be the major causes of childhood recurrent abdominal pain (RAP). It is known that Helicobacter pylori (H. Pylori) is related to chronic gastritis and pediatric peptic ulcer. However,the association between H. Pylori infection and RAP still needs to be investigated. Now there is not a safe, simple, reliable, and non-invasive method for clinical diagnosis of H. Pylori infection in pediatric practice. So the purpose was of this study to investigate the relationship between RAP and H. Pylori infection and the value of H. Pylori stool antigen (HpSA ) in the etiological diagnosis of childhood RAP. METHODS: One hundred and eighty-two children with RAP received both 13C-urea breath test( 13C -UBT )and HpSA test for the determination of H. Pylori infection. An anti-H. Pylori therapy was administered in RAP children with H. Pylori infection. The clinical symptom (abdominal pain) was observed after anti-H. Pylori treatment. RESULTS: Of the 182 children with RAP, 75(41.2%) were found to be H. Pylori-positive according to the 13C-UBT results, without gender difference in H. Pylori infection incidence. Sixty-eight RAP patients presented H. Pylori-positive in both 13C -UBT and HpSA test. After anti-H. Pylori treatment abdominal pain was alleviated in 93.4% of children whose H. Pylori eradication was successful,but only in 28.6% of those whose eradication was unsuccessful (P<0.05).When 13C-UBT served as a "gold standard", the sensitivity, specificity, accuracy, false-positive and false-negative rates, and positive predictive and negative predictive values of HpSA test were 90.7%, 97.2%, 2.8%, 9.3%, 94.5%, 95.8% and 93.7%, respectively. The concordance between HpSA test and 13C-UBT was expressed in Kappa=0.886, U=25.237, and P=0. CONCLUSIONS: H. Pylori infection is associated with RAP in children.The HpSA test is a simple, cost-effective and reliable method for the detection of H.Pylori infection and may be used in the etiological diagnosis of childhood RAP.

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OBJECTIVE: This study aimed to investigate the therapeutic effect of iron supplementation combined with anti-Helicobacter pylori(H.Pylori) therapy on patients with iron-deficiency anemia with concomitant H.Pylori infection. METHODS: Sixty-eight out of 143 children with iron-deficiency anemia were confirmed to have concomitant H. Pylori infection by the 13C-urea breath test. The 68 patients were randomly assigned into two groups: Study group (n=35) and Control group (n=33). The Control group received oral ferrous sulfate, with a dosage of 2 mg/kg for three times daily. Iron supplementation together with anti-H.Pylori therapy (losec 0.8 mg/kg, amoxicillin 50 mg/kg and clazithromycin 15 mg/kg daily for two weeks) was administered in the Study group. The therapeutic effect was compared between the two groups. RESULTS: At the 8th week after treatment, the levels of hemoglobin, serum iron and serum ferritin in the two groups significantly increased. The Study group showed significantly higher levels of hemoglobin, serum iron and serum ferritin than the Control group. CONCLUSIONS: H.Pylori infection may be associated with iron-deficiency anemia. Iron supplementation together with anti-H.Pylori therapy is more effective than iron supplementation therapy alone on children with iron-deficiency anemia with concomitant H.Pylori infection.

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OBJECTIVE: Prenteral nutrition therapy helps to increase the survival rate of preterm infants. However, due to their immature functions of liver, kidneys and lungs, and the poor capacity of lipid clearances and antioxidation, the dysfunction of hepatobiliary system induced by parenteral nutrition has drawn more attentions. Thus, this study was designed to investigate the effects of parenteral nutrition on the hepatobiliary function in preterm infants. METHODS: Seventy-five preterm infants who received partial parenteral nutrition from 1999 to 2004 were enrolled (Study group). Forty-nine preterm infants whose calories were provided only by glucose or glucose-containing electrolyte solutions were used as Control group. The two groups were matched in gender, gestational age, birth weight and Apgar scores at birth. The results of hepatobiliary function-related biochemical markers during parenteral nutritional administration were analyzed. RESULTS: After parenteral nutritional administration, the levels of serum glutamic oxaloacetic transaminase(AST), total bilirubin(TBIL), and indirect bilirubin(IBIL)in both groups decreased significantly(P<0.01), but the levels of serum glutamic pyruvic transaminase(ALT)and direct bilirubin(DBIL) remained unchanged. In the Study group, the level of serum total bile acid(TBA)increased significantly after parenteral nutritional administration (32.09±18.23 μmol/L vs 14.92±10.87 μmol/L , P<0.01). It was positively correlated to the duration of parenteral nutrition,and negatively to the gestational age. The TBA level of the Control group was not significantly different before and after nutritional administration. CONCLUSIONS: The TBA level significantly increased after parenteral nutrition administration, suggesting that parenteral nutrition-related cholestasis might developed in preterm infants.

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OBJECTIVE: This study reported the case of a 3-year-old boy with biotinidase deficiency. The child was admitted with a 6 month history of alopecia and tetter and progressive lower limbs flaccidity for 3 months. Urinary organic acid analysis with gas chromatograph/mass spectrometry and biotinidase activity assay of blood confirmed the diagnosis of biotinidase deficiency. He presented with neurological abnormalities and dermatological lesions. Biotin supplementation (20 mg/d) led to a dramatic improvement of the symptoms. It was concluded that early diagnosis and biotin supplementation can greatly improve the outcome of patients.

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OBJECTIVE: Intrauterine growth retardation (IUGR) may contribute to the disorder of brain development of fetuses. Because ligustrazine has been proved to be effective in improving blood circulation and relieving clot formation, it has been used to treat hypoxic-ischemic brain damage of the newborn. This study aimed to explore the effect of ligustrazine on the brain development in fetal rats with IUGR induced by passive smoking and its mechanism. METHODS: Thirty-six pregnant rats were randomly assigned into four groups: Control, Model, Low dose (40-mg/kg ligustrazine) and High dose (80-mg/kg ligustrazine) (n=9 each). IUGR was induced by passive smoking in rats from the last three groups. Ligustrazine was administered for the last two groups between day 8 and day 20 of gestation. On day 21 of gestation, the fetal rats were delivered by cesarean section. The body weight, brain weight, liver weight, body length and tail length of fetal rats were measured. The levels of nitric oxide(NO), malondialdehyde(MDA) and superoxide dismutase(SOD) activity in the brains of fetal rats were examined. RESULTS: The incidence of IUGR in the Control, Model, and the Low and High dose ligustrazine treated groups was 3.9%(4/105), 55.0%(50/106), 11.8%(11/103) and 5.4%(5/99) respectively. The average body weight(3.1±0.3-g vs 3.8±0.6-g), brain weight (0.144±0.012-g vs 0.176±0.018-g)and liver weight (0.29±0.06-g vs 0.34±0.07-g)of fetal rats in the Model group were all significantly lower than those of the Control group(P<0.01). Those in the two treatment groups were significantly higher than in the IUGR group. The levels of NO (52.4±1.4-μmol/g vs 43.7±6.7-μmol/g)and MDA (273.5±8.5-μmol/g vs 249.6±6.2-μmol/g)in the brains of fetal rats of the Model group increased significantly compared with those of the Control group(both P<0.01), but the activity of SOD of the Model group decreased compared with the Control group(29.7±2.6-U/mg vs 36.5±3.9-U/mg)(P<0.01). In the Ligustrazine treated groups, the levels of MDA decreased and the levels of SOD activity increased compared with the Model group(both P<0.01), but the levels of NO were higher than those of Model group. CONCLUSIONS: Administering ligustrazine during pregnancy can decrease the incidence of fetal IUGR induced by passive smoking and improve the brain development of fetal rats. The effect of ligustrazine works possibly by redressing the unbalance between oxidate and antioxidate system.

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OBJECTIVE: Activation of calcium-dependent neutral proteinase, Caplain, can induce apoptosis of neuron and Caplain inhibitor-3 (MDL28170) has protective effects against brain ischemia in adult animals. Whether it also has protective effects on neonatal animals with hypoxic-ischemic brain damage (HIBD) is has not been determined. In this study, the effect of MDL28170 on Caspase-3 expression and apoptosis in hippocampal CA1 region of neonatal rats after HIBD was examined to explore its neural protective effect on neonatal animals and the possible underlying mechanism. METHODS: Seven-day-old Sprague-Dawley rat pups were randomly assigned into three groups: HIBD (n=40), MDL (n=40) and Control (n=8). The pups in the first two groups were subjected to unilateral ligation of the right carotid artery followed by 2 hrs of hypoxia (8% O_2). The pups in the MDL group were intraperitoneally injected with MDL28170 (50-mg/kg) at 0, 2 and 4 hrs after hypoxia-ischemia(HI), while those in the Control and HIBD groups were intraperitoneally injected with normal saline instead. The rats in the HIBD and MDL groups were sacrificed at 6, 12, 24, 48 and 72 hrs after HI (8 rats in each group at each time point). Immunohistochemistry and terminal deoxynucleotidyl transferase mediated d-UTP nick end labeling staining (TUNEL) were used to detect the Caspase-3 expression and neuronal apoptosis in hippocampal CA1 region. RESULTS: In the HIBD group, Caspase-3 expression in hippocampal CA1 region increased at 6 hrs after HI compared with the Control group (13.4±3.5/HP vs 2.6±0.6/HP,P=0.028), peaking at 48 hrs (27.1±4.1/HP) and remaining higher at 72 hrs (22.6±4.8/HP,P<0.001). The number of TUNEL-positive neurons in the HIBD group increased at 6 hrs after HI, and were significantly greater than those of the Control group at 12 hrs (25.0± 1.7/HP vs 2.3±1.5, P<0.001). At 48 hrs after HI, the number of TUNEL-positive neurons peaked (67.8±2.6/HP) and remained greater at 72 hrs (44.3±6.8/HP). The treatment with MDL28170 attenuated the Caspase-3 expression and reduced the number of TUNEL-positive neurons within 48 hrs after HI when compared with the HIBD group (P<0.05), but the effect significantly decreased at 72 hrs. CONCLUSIONS: MDL28170 can inhibit the Caspase-3 expression and reduce the apoptotic cells in hippocampal CA1 region, thereby yielding protective effects against HIBD in neonatal rats.

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OBJECTIVE: Hyperoxia-induced lung injury is the most common cause of bronchopulmonary dysplasia (BPD) in neonates. Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen that can regulate proliferation, differentiation and angiogensis of endothelial cells in neonatal lungs. This paper aimed to study the changes of VEGF expression in the lungs of neonatal rats exposed to prolonged hyperoxia so as to explore the mechanism of BPD. METHODS: Wistar rat pups were randomized to hyperoxia (Hyperoxia group, FiO_2=0.95) or room air exposure (Normoxia group) (both n=30) from postnatal 12 hrs. The rats were sacrificed at postnatal days 1, 2, 3, 7, 14 and 21 (5 rats each time point) and their lungs were collected. The lung sections were stained with hematoxylin and eosin for histological evaluation. Expressions of VEGF protein and mRNA were detected by immunohistochemistry and in situ hybridization. Results were expressed as gray values. The higher the value, the lower the expressions. RESULTS: After being exposed to hyperoxia for 7 days, lung tissues developed interstitial fibrosis, abnormal vascular constitution and a decreased alveolar septation. These changes became more obvious with the time of prolonged hyperoxia exposure. Expressions of VEGF protein at 3 and 7 days of exposure in the Hyperoxia group decreased significantly as compared with the Normoxia group (81.9±0.8 vs 80.8±1.0,82.8±1.2 vs 79.2±1.6,P<0.01). The expression of VEGF mRNA in the Hyperoxia group was also lower at 3 and 7 days of exposure (89.5± 1.1 vs 88.0±1.0, 91.1±1.5 vs 87.7±1.7, P<0.001). Both VEGF protein and mRNA levels gradually decreased with the hyperoxia exposure time and their levels could not be detected at 14 and 21 days of hyperoxia exposure. CONCLUSIONS: Hyperoxia exposure inhibited the expression of lung VEGF in neonatal rats, which may be the underlying mechanism of hyperoxia-induced BPD.

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OBJECTIVE: To explore the temporal expression of tumor necrosis factor-α(TNF-α) and Caspase-3 in hyperoxia-induced lung injury in preterm rats. METHODS: Two-day-old Sprague-Dawley preterm rats were randomly divided into Air group and Hyperoxia group (both n=40). Rats in the Hyperoxia group were exposed to 85% O_2, while rats in the Air group were exposed to air. The rats in each group were sacrificed at 1, 4, 7, 14 and 21 days after exposure (8 rats at each time point), and lung tissues were collected. Pathomorphology of the lungs was observed by hematoxylin-eosin staining. The contents of TNF-α in the homogenate of lungs were detected using ELISA. The expression of Caspase-3 was detected by immunohistochemistry and Western blot. RESULTS: The contents of TNF-α in the homogenate of lungs increased significantly at 4, 7 and 14 days after exposure, and the expressions of Caspase-3 were also enhanced, as compared with those of the Air group(P<0.01). The expression of Caspase-3 positively correlated with the contents of TNF-α (r=0.93,P<0.01). CONCLUSIONS: Over-expression of Caspase-3 induced by TNF-α might be one of the underlying mechanisms of hyperoxia-induced lung injury in preterm rats

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OBJECTIVE: The reference values of pulmonary function for healthy schoolchildren were established between late 1980's and early 1990's. Whether the improvement of life quality influences the pulmonary function values of schoolchildren remains unknown. Moreover, the pulmonary function values of children from different regions might be different. This study aimed to investigate the mean values of pulmonary function parameters in healthy children aged 6 to 12 years in Guangzhou. METHODS: Spirolite TM 303 pulmonary function test spirometer was used to measure the mean values of pulmonary function parameters, including forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV_1), peak expiratory flow (PEF) and forced expiratory flow during middle half of FVC (FEF_ 25%-75%), in 280 healthy schoolchildren between 6 and 12 years old of both sexes from a primary school of Guangzhou. The subjects selected by random sampling were assigned into 7 groups according age (n=40 each), 1 year as a group separation. Their weights and heights were measured. RESULTS: In 139 boys the mean weight and height were 32.93±7.39 kg and 135.05±13.42 cm, respectively. The mean FVC was 3.40±0.96 L, FEV_1 3.03±0.87 L, PEF 6.42±2.32 L and FEF_ 25%-75% 3.58±1.32 L . In 141 girls the mean weight and height were 33.06±6.85 kg and 135.66±12.62 cm, respectively. The mean FVC was 3.22±1.07 L, FEV_1 2.88±0.93 L, PEF 5.84±2.17 L and FEF_ 25%-75% 3.59±1.28 L. Monovariable analysis showed that all the four parameters were positively related to height and weight but multivariable regression analysis did not demonstrate a correlation between the four parameters and weight. Monovariable analysis showed that PEF was related to gender but FVC, FEV_1 and FEF_ 25%-75%, were irrelevant. However multivariable regression analysis showed that FVC and FEV_1 were also correlated to gender. Either the monovariable analysis or the multivariable regression analysis demonstrated that all the four parameters were positively related to age. CONCLUSIONS: This study reported a reference range of the pulmonary function values for healthy schoolchildren aged 6 to 12 years in Guangzhou. Age, height, weight and gender may be related to the pulmonary function values. Among them, age and height are more important impact factors.

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Objective This study performed multicenter neonatal hearing screening in the Dongguang region so as to explore the model of neonatal hearing screening suitable for this region.Methods The study population consisted of 17 360 infants from 6 hospitals of Dongguang region. Universal hearing screenings by distortion product otoacoustic emission (DPOAE) techniques were done within 24- 48 hrs after birth. Infants who failed the initial screening test underwent second screening by DPOAE one month later. Acoustic brain-stem response (ABR) and 40 Hz auditory event related potential (40Hz-AERP)techniques were used to examine the hearing of those who failed the second hearing screening test at age of 3 months.Results Of the 17 360 infants, 15 624(89.1%)passed the initial screening. A total of 1 736 cases needed a second screening test. One thousand five hundred and ninety seven infants underwent the second test. Among the 1 597 cases, 1 491(93.4%) passed the second screening. Ultimately 39 cases were diagnosed with congenital hearing loss, with an incidence of hearing loss of 2.25‰.Conclusions DPOAE can be used as a rapid and effective method for initial hearing screening in infants. The two-stage hearing screening test can identify hearing loss early.

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