Expression of Occludin in lung tissues of newborn rats with bronchopulmonary dysplasia and its influence on pulmonary epithelial permeability / 中华实用儿科临床杂志

Objective To explore the dynamic changes of Occludin gene and protein levels in lung tissues of newborn rats with hyperoxia-induced bronchopulmonary dysplasia (BPD) in the early phase and its effect on pulmonary epithelial permeability.Methods One hundred and sixty newborn Wistar rats were randomly assigned to hyperoxia group (900 mL/L oxygen)and normoxia group (210 mL/L oxygen) according to different oxygen concentrations,80rats in each group.Rats were sacrificed and lung tissues were removed on 1,3,5,7 d after treatment.Bronchoalveolar lavage fluid (BALF):serum FD4 ratio was detected;location and expression of Occludin were examined by immunofluorescence staining and Western blot; messenger RNA (mRNA) was studied by reverse transcription-PCR.Results There was no obvious difference in the BALF and serum FD4 ratio (1.533 ±0.122 vs 1.575 ± 0.140,P ＞ 0.05) between the hyperoxia group and the normoxia group on the first day.After 3 days of hyperoxia exposure,the ratio of FD4between BALF and serum was significantly higher than that in the normoxia group(1.365 ±0.159 vs 1.615 ±0.196,P ＜ 0.05).And after 5 or 7 days of hyperoxia exposure,the ratio of FD4 between BALF and serum was dramatically increased(1.245 ±0.152 vs 3.211 ±0.799,1.178 ± 0.594 vs 5.15 ± 0.967,all P ＜ 0.01).On the 7 day,immunofluorescence staining showed Occludin distribllted in a consecutive line along lung epithelial cell membrane in the normoxia group,while in the hyperoxia group Occludin was distributed in a discontinuous line and lacking intensity.There was no obvious difference in Occludin mRNA level between the hyperoxia group and normoxia group on the first day(2.15 ±0.33 vs 2.23 ± 0.39,P ＞ 0.05).Compared to the normoxia group,the decrease in Occludin mRNA level was statistically significant after 3 or 5 days of hyperoxia exposure(2.46 ± 0.27 vs 2.00 ± 0.19,2.62 ± 0.28 vs 2.15 ± 0.20,all P ＜ 0.05),and after 7 days of hyperoxia exposure,the Occludin mRNA level dramatically declined (3.08 ± 0.43 vs 2.01 ±0.34,P ＜0.01).There was no obvious difference in Occludin protein level between the hyperoxia group and normoxia group on the 1 st and the 3th day(1.00 ± 0.05 vs 1.05 ± 0.03,1.24 ± 0.06 vs 1.17 ± 0.04,all P ＞ 0.05).Compared to the normoxia groups,the decrease in Occludin protein level was statistically significant after 5 days of hyperoxia exposure (1.03 ± 0.04 vs 0.93 ± 0.05,P ＜ 0.05),and after 7 days of hyperoxia exposure,the Occludin protein level dramatically declined(0.96 ± 0.14 vs 0.65 ± 0.07,P ＜ 0.01).There was a significantly negative correlation between Occludin protein expression and pulmonary epithelial permeability after hyperoxia exposure (r =-0.755,P ＜0.01).Conclusions Downregulation of Occludin hyperoxia-induced may lead to the increase of pulmonary epithelial paracellular permeability,which participates in the development of pulmonary edema in the early phase of BPD induced by hyperoxia.

Expression and significance of KL-6/MUC1 in lung tissue of newborn rats with hyperoxia-induced bronchopulmonary dysplasia / 中华实用儿科临床杂志

Objective To explore the expression of KL-6/MUC1 and the possible impact on alveolar development in lung tissue of newborn rats with hyperoxia-induced bronchopulmonary dysplasia (BPD).Methods Sixty-four newborn rats were randomly divided into 2 groups:hyperoxic group and control group.The rats in hyperoxic group were exposed to high oxygen volume fraction of 900 mL/L,and the rats in control group were exposed to normal oxygen volume fraction of 210 mL/L.The experimental control factors were the same in two groups.Eight rats were randomly selected from each group on day 1,3,7,and 14 after oxygen exposure.The alveolar development was evaluated by the number of radial alveolar count (RAC) and the alveolar area/pulmonary septal area ratio (A/S).The location,distribution,and expression of KL-6/MUC1 in the lung tissue were detected by the fluorescent immunoassay,Western blot,and reverse transcription polymerase chain reaction.Results Compared with the control group,the RAC in hyperoxic group decreased on day 3 and continued to decline on day 14.The A/S in hyperoxic group increased on day 7 and peaked on day 14 (P ＜0.05).KL-6/MUC1 expressed in both bronchial epithelial cells and alveolar epithelial cells of newborn rats.KL-6/MUC1 protein in hyperoxic group peaked on day 1 and decreased later,which was higher than that of the control group (P ＜ 0.05),the level of KL-6/MUC1 was positively correlated with RAC (r =0.707,P ＜ 0.05)and negatively correlated with A/S(r =-0.716,P ＜ 0.05).MUC1 mRNA in hyperoxic group was slightly higher than that in control group,but no significant inter-or intra-group difference was observed (P ＞ 0.05).Conclusions The highest expression of KL-6/MUC1 can be observed in the early phase of hyperoxic exposure,and it decreases to the lowest on the key point of pulmonary development.KL-6/MUC1 may play an important role in the alveolar development.

Etiology analysis of upper airway obstruction in 54 newborn infants / 中华实用儿科临床杂志

Objective To explore the etiology of neonatal upper airway obstruction(UAO) in order to perform early diagnosis and treatment,and to improve the prognosis.Methods Retrospectively analysis of the clinical data of 54 cases of neonatal UAO in Shengjing Hospital of China Medical University from Jan.2005 to Dec.2011 was performed.All patients received CT three dimensional reconstruction reconstruction,30 patients received the direct laryngoscopy,5 cases received the video laryngoscope,8 cases received pathological examination.All the cases received the determination of serum total calcium and ionized calcium,6 cases received upper gastrointestinal imaging,8 cases received chromosome inspection and 20 cases received echocardiography.Results CT scan:abnormal in 21 cases,among them 15 cases of congenital cyst,5 cases of tongue fall blocking airway,and 1 case of choanal atresia(bilateral) ;another 33 patients were normal.Direct laryngoscopy results:abnormal in 13 cases,among them 12 cases of congenital cyst,and 1 case of glossoptosis;another 17 cases were normal.Electronic laryngoscopy results:5 cases were diagnosed as congenital laryngomalacia.Pathological examination results:7 cases of cyst wall by squamous epithelium composition,and 1 case of cyst wall by columnar epithelium composition.Serum total calcium and ion calcium level results:all patients were in the normal range.Chromosome examination results were normal.Upper gastrointestinal imaging results:1 normal case,5 cases of mild gastroesophageal reflux.Echocardiography results:4 cases were normal,10 cases of patent foramen ovale,2 cases of patent ductus arteriosus,4 cases of congenital heart disease (2 cases of atrial septum defect,1 case of ventricular septal defect,and 1 case of interatrial septum merger ventricular septal defect).Conclusions In the etiology of neonatal UAO,there is a lot of organic diseases except for congenital laryngomalacia.For the UAO induced by laryngeal stridor or undefinitely cause,CT scan should be taken as soon as possible.

Effects of TGF-β1 on gene expression of connective tissue growth factor in lung fibroblasts / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the effects of transforming growth factor-β1 (TGF-β1) on the gene expression of connective tissue growth factor (CTGF) in cultured lung fibroblasts of embryonic rats in vitro.</p><p><b>METHODS</b>Wistar rats of embryonic 19 days were used for primary culture of lung fibroblasts (LFs). The cells in the experimental group were treated by different concentrations (1, 5 or 10 ng/mL) and different durations (12, 24 or 48 hrs) of TGF-β1 to stimulate the LFs. The cells in the control group were cultured in serum-free medium. RT-PCR method was applied to detect CTGF mRNA expression in LFs.</p><p><b>RESULTS</b>Compared with the control group, the levels of CTGF mRNA in LFs in the experimental group increased significantly (P<0.05). CTGF mRNA expression gradually increased with increasing concentration and duration of TGF-β1 treatment (P<0.05).</p><p><b>CONCLUSIONS</b>TGF-β1 can stimulate CTGF gene expression in LFs and increase CTGF gene expression in a dose-and time-dependent manner.</p>

Expression of ERK1/2 protein in lung tissues of newborn rats with hyperoxia-induced chronic lung disease / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the expression of extracellular signal regulated protein kinase (ERK) 1/2 in lung tissues of newborn rats with chronic lung disease (CLD) caused by hyperoxia.</p><p><b>METHODS</b>Forty-eight full-term newborn rats were randomly divided into two groups: hyperoxia and control. The two groups were exposed to a hyperoxic gas mixture (0.90 O(2)) for an induction of CLD and room air within 12 hrs after birth, respectively. The levels of ERK1/2 protein and mRNA in lung tissues were measured using immunohistochemistry, Western blot and real-time PCR methods on postnatal days 3, 7 and 14. The severity of pulmonary fibrosis was evaluated.</p><p><b>RESULTS</b>The expression of p-ERK protein in lung tissues in the hyperoxia group was significantly higher than that in the control group on postnatal days 7 and 14 (P<0.01). There were no significant differences in the levels of total ERK1/2 protein and ERK1/2 mRNA.</p><p><b>CONCLUSIONS</b>The activation of phosphorated ERK1/2 may lead to lung fibrosis caused by hyperoxia in newborn rats.</p>

Effects of hyperoxia on erythropoietin receptor expression in lung development of neonatal rats / 中华儿科杂志

<p><b>OBJECTIVE</b>Oxygen toxicity is thought to be a major contributing factor in the pathogenesis of bronchopulmonary dysplasia (BPD). Animal experiments reveal that erythropoietin (EPO) may have protective effects against hyperoxic lung injury, but the mechanisms remain unknown. The aim of this study was to evaluate effects of hyperoxia on erythropoietin receptor expression in lung development of neonatal rats.</p><p><b>METHODS</b>Several litters of Wistar pups were pooled together within 12 hours after birth and randomly divided into two groups (n = 24 in each): air-exposed control group and hyperoxia-exposed group. In hyperoxia-exposed group, the rats were exposed to 85% oxygen. Pups (n = 8) from each group were sacrificed on postnatal days 3, 7, and 14. The pulmonary histological and morphometric changes were observed after hematoxylin-eosin (HE) staining under light microscope. Radical alveolar counts (RAC) were compared between the two groups to evaluate the differences of alveolarization. Expressions of platelet endothelial cell adhesion molecule-1 (PECAM-1) and erythropoietin receptor (EPOR) in lung tissue were measured by immunohistochemistry. Expressions of EPOR mRNA and EPOR protein were measured by RT-PCR and Western blotting.</p><p><b>RESULTS</b>In hyperoxia-exposed group, there were a few inflammatory cells infiltration in interstitium on day 3 and inflammatory response worsened on day 7. Alveolar and capillary hypoplasia and interstitial fibrosis were evident on day 14. RAC increased in air-exposed control group along with the age in days. RAC decreased from day 7 in hyperoxia-exposed group compared with air-exposed control group [(6.85 ± 1.04) vs. (7.33 ± 1.0), P < 0.01], which was more evident on day 14 [(6.20 ± 1.58) vs. (9.07 ± 0.69), P < 0.001]. Expression of PECAM-1 protein increased in air-exposed control group along with the age in days. But in hyperoxia-exposed group, it decreased on day 7 and 14 [(15.14 ± 1.51) vs. (31.47 ± 2.43), (11.04 ± 1.76) vs. (41.41 ± 3.83), P < 0.001] compared with air-exposed control group. Expression of EPOR on day 3 in air-exposed control group was the strongest and weakened gradually with the increase of postnatal days. Expression of EPOR in hyperoxia-exposed group decreased on day 3 and became more evident on day 7 and day 14 compared with air-exposed control group [(1.62 ± 0.04) vs. (1.82 ± 0.06), P < 0.05; (0.48 ± 0.01) vs. (1.10 ± 0.07), (0.39 ± 0.04) vs. (0.87 ± 0.03), P < 0.001]. Expression of EPOR mRNA on day 3 in air-exposed control group was the strongest and was decreased significantly in hyperoxia-exposed group compared with air-exposed control group at all time points [(0.87 ± 0.07) vs. (1.1 ± 0.17), (0.18 ± 0.07) vs. (0.36 ± 0.08), P < 0.01;(0.14 ± 0.05) vs. (0.36 ± 0.09), P < 0.001].</p><p><b>CONCLUSIONS</b>EPOR may participate in the modulation of normal lung development. Depressed expression of EPOR and PECAM-1 may be involved in the pathogenesis of alveolar and capillary hypoplasia induced by hyperoxia.</p>

Early prediction of the injured regions in neonatal brain with hypoxic-ischemic encephalopathy by diffusion weighted imaging and measuring their apparent diffusion coefficient / 中华儿科杂志

<p><b>OBJECTIVE</b>To elucidate that diffusion weighted imaging (DWI) can be used to predict the injured regions of neonatal brain with hypoxic-ischemic encephalopathy (HIE) in the early phase of injury, and to measure the apparent diffusion coefficient (ADC) values in the multiple regions of the brain.</p><p><b>METHOD</b>The participants in this study were twenty-six infants with HIE from neonatology ward hospitalized between July 2006 and July 2009. Nineteen patients had severe HIE, and seven had moderate HIE. DWI and conventional magnetic resonance imaging (MRI) were performed for each case within the first 72 hrs. The ADC values of eight regions of interest (ROIs) were measured in ten cases with severe HIE (ADC values group). ROIs included posterior limb of internal capsule (PLIC), ventrolateral thalami, basal ganglia, perirolandic cortex, occipital cortex, centrum semiovale, brainstem, and frontal white matter. Twelve neonates were enrolled as the control subjects.</p><p><b>RESULTS</b>During the first 72 hrs, the conventional MRI of 26 patients showed subarachnoid hemorrhage in 5, subdural hemorrhage in 2, and mild high signal intensity in the cortex of only one patient. In the 19 cases with severe HIE, abnormal signal intensities were seen in ventrolateral thalami and perirolandic cortex of 17 patients (89%), and the remaining 2 infants showed abnormal cortex and subcortical white matter. In 7 cases with moderate HIE, 4 had abnormal signal intensity in the cortex and subcortical white matter, 2 had abnormal periventricular white matter, and only one showed abnormal signal intensity in the ventrolateral thalami and perirolandic cortex. In the ADC values group, the average ADC values of posterior limb of internal capsule (PLIC), ventrolateral thalami, basal ganglia, perirolandic cortex, occipital cortex, centrum semiovale, brainstem, and frontal white matter respectively were 0.68 (0.56 - 0.88), 0.73 ± 0.13, 0.67 ± 0.11, 0.78 ± 0.22, 0.90 ± 0.16, 0.87 ± 0.21, 0.73 ± 0.19, 1.32 ± 0.22 × 10(-3) mm(2)/S. In the control group, the average ADC values of posterior limb of internal capsule (PLIC), ventrolateral thalami, basal ganglia, perirolandic cortex, occipital cortex, centrum semiovale, brainstem, and frontal white matter respectively were 0.96 (0.95 - 1.02), 1.02 ± 0.90, 1.15 ± 0.99, 1.08 ± 0.07, 1.09 ± 0.08, 1.39 ± 0.20, 0.96 ± 0.05, 1.58 ± 0.18× 10(-3) mm(2)/S. There was statistically significant difference in the average ADC values between each of 8 ROIs of infants with HIE and healthy neonates (P < 0.01).</p><p><b>CONCLUSION</b>In the first days after birth, the major injured regions of severe HIE were ventrolateral thalami and perirolandic cortex, the minor injured regions were cortex and subcortical white matter. Multiple regions of moderate HIE were injured, including cortex with subcortical white matter, periventricular white matter, and ventrolateral thalami with perirolandic cortex. The ADC values of the regions with abnormal signal intensity decreased, also some regions with the normal signal intensity.</p>

Early diagnosis of lingual thyroglossal duct cyst in newborns: analysis of 10 cases previously misdiagnosed as laryngomalacia / 中华儿科杂志

<p><b>OBJECTIVE</b>To distinguish lingual thyroglossal duct cyst (LTDC) from laryngomalacia in newborn infants.</p><p><b>METHODS</b>Data of 10 newborn infants with laryngeal stridor and dyspnea, admitted to the department of neonatology in our hospital during December, 2004 to August, 2007, who were finally diagnosed with LTDC though previously diagnosed as congenital laryngeal stridor in other hospitals, were summarized and analyzed.</p><p><b>RESULTS</b>Inspiratory stridor with chest wall retractions was cardinal symptom of newborn with LTDC. A slightly gray and round cyst with smooth surface at the base of the tongue was found with laryngoscopy. On computed tomography examination of larynx, a well-circumscribed lesion with low intensity was detected at the base of the tongue protruding into the air passage. Pathological examination demonstrated that the cyst wall was composed of tabular and columnar epithelium.</p><p><b>CONCLUSIONS</b>LTDC is a common disease in newborns, which is similar to laryngomalacia. For neonates suspected of LTDC, laryngoscopic examination should be performed first, while laryngeal CT scan is an important diagnostic basis. Cyst puncture can ameliorate the symptoms of the patients, while surgical removal is the method of radical cure.</p>

Effect of melatonin on hyperoxia-induced oxidant/antioxidant imbalance in the lung of neonatal rats with chronic lung disease / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the effect of melatonin, a potent antioxidant both in vitro and in vivo, on hyperoxia-induced oxidant/antioxidant imbalance in the lung of neonatal rats with chronic lung disease (CLD).</p><p><b>METHODS</b>Ninety neonatal rats were randomly divided into three groups (n=30 each): air-exposed, hyperoxia-exposed, melatonin-treated (4 mg/kg melatonin was administered 30 minutes before hyperoxia exposure and once daily after exposure). CLD was induced by hyperoxia exposure (FiO2=0.85). Lung specimens were obtained 3, 7, and 14 days after exposure (n=10 each) for histopathologic examination. The levels of total antioxydase capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), myeloperoxidase (MPO), catalase (CAT), nitrite/nitrate, and malondialdehyde (MDA) in the lung were assayed by the spectrophotometer.</p><p><b>RESULTS</b>The histopathologic examination showed that lung damage was obviously alleviated in the melatonin-treated group. The levels of T-AOC, GSH-Px, SOD and CAT in the lung were significantly higher in the melatonin-treated group than those in the other two groups at all time points (p<0.05). The levels of MPO, nitrite/nitrate and MDA in the lung increased significantly in the untreated hypoxia-exposed group compared with those in the air-exposed group at all time points (p<0.05 or 0.01), while the levels of MPO, nitrite/nitrate and MDA in the melatonin-treated group were significantly reduced as compared with the untreated hypoxia-exposed group (p<0.05).</p><p><b>CONCLUSIONS</b>Melatonin may reverse oxidant/antioxidant imbalance in hyperoxia-induced lung disease, thus providing a protective effect against CLD in neonatal rats.</p>

Expression of HoxB5, SPC and AQP5 in neonatal rats with hyperoxia-induced chronic lung disease / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Alveolar epithelium impairment is one of pathological changes associated with chronic lung disease (CLD). Hoxb5 is one of the few homeobox genes strongly expressed in the developing lung. This study investigated the expression of HoxB5, SPC and AQP5 in rats with CLD in order to explore the role of Hoxb-5 in impairment and reparation of alveolar epithelium.</p><p><b>METHODS</b>Eighty neonatal rats were randomly exposed to hyperoxia (model group) or to room air (control group) (n=40 each). The CLD model was induced by hyperoxia exposure. The expression of HoxB5, SPC and AQP5 protein and mRNA in the lung tissue was detected by immunohistochemistry and RT-PCR 1, 3, 7, 14 and 21 days after exposure.</p><p><b>RESULTS</b>In the model group HoxB5 expression significantly decreased 7, 14 and 21 days after hyperoxia exposure. SPC expression decreased 3 days after hyperoxia exposure but increased significantly 7, 14 and 21 days after hyperoxia exposure as compared to the control group. AQP5 expression was progressively reduced with prolonged hyperoxia exposure.</p><p><b>CONCLUSIONS</b>Hyperoxia exposure may lead to alveolar epithelial cell (AEC) damage in neonatal rats. The increased SPC expression and decreased AQP5 expression suggested that the ability of differentiation and transformation of AECII into AECI decreased in neonatal rats with CLD. The decreased HoxB5 expression following hyperoxia exposure might contribute to a decreased ability of differentiation of AECII.</p>

Anti-inflammatory effects of erythropoietin on hyperoxia-induced bronchopulmonary dysplasia in newborn rats / 中华儿科杂志

<p><b>OBJECTIVE</b>Bronchopulmonary dysplasia (BPD) is a multifactorial disease resulting from the impact of injury (including oxygen toxicity, barotrauma, volutrauma, and infection) on the immature lung. Oxygen toxicity is thought to be a major contributing factor in the pathogenesis in BPD. Previous animal studies have shown that exposure to hyperoxia in the neonatal period causes lung structural changes that are similar to the histology seen in human infants with BPD. Erythropoietin (EPO) has pleiotropic actions including antioxidant, anti-apoptotic, anti-inflammatory and angiogenic effects. Animal experiments reveal that EPO may have protective effects on hyperoxic lung injury, but the mechanisms remain unknown. The aim of the study was to evaluate the anti-inflammatory effects and understand mechanism of action of EPO on the hyperoxia-induced BPD in newborn rats.</p><p><b>METHOD</b>Several litters of Wistar pups were pooled together within 12 hours after birth and randomly divided into four groups: I. air-exposed control group, II. air-exposed human recombinant erythropoietin (rhEPO)-treated group, III. hyperoxia-exposed placebo group and IV. hyperoxia-exposed rhEPO-treated group . Group III and IV rats were exposed to 85% oxygen. Group II and IV rats received rhEPO (1200 IU/kg) subcutaneously on postnatal days 0 and 2. Group I and III received 0.9% saline in the same way. Pups from each group were sacrificed on days 3, 7, and 14. Blood hemoglobin concentration, hematocrit and platelet count were determined by blood cell analyzer. Total protein content in bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) were measured by biochemical assay. Changes of monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant-1 (CINC-1) mRNA expressions were measured by RT-PCR.</p><p><b>RESULT</b>In group III, there were a few inflammatory cells infiltrations in interstitium on day 3 and inflammatory response worsened on day 7. Alveolar and capillary hypoplasia and interstitial fibrosis were evident on day 14. The pathological changes were ameliorated greatly in group IV and the survival was prolonged. There were no abnormal raises of hemoglobin concentration, hematocrit and platelet count in group IV compared with group I. Total protein concentration in BALF was measured as a marker for capillary leakage. MPO is a major constituent of neutrophil cytoplasmic granules and its activity therefore is a direct measure of neutrophil presence and an indirect indicator of lung injury. Total protein concentration and MPO in BALF were greatly depressed in group IV compared with group III, P<0.05, P<0.001. The upregulation of genes of CINC-1 and MCP-1 was closely related with lung inflammation caused by oxidative stress. MCP-1 and CINC-1 mRNA expression were detected and it was found that their changes were in line with the degree of lung inflammation. MCP-1 and CINC-1 mRNA expression increased in group III compared with group I especially on day 7, P<0.01 or <0.001. The changes of MCP-1 and CINC-1 mRNA were positively correlated with changes of MPO in BALF covering all groups on days 3, 7 and 14, respectively (r = 0.391, P<0.05; r = 0.701, P<0.01; r = 0.600, P<0.01; r = 0.471, P<0.01; r = 0.789, P<0.01; r = 0.588, P<0.01).</p><p><b>CONCLUSION</b>EPO could significantly reduce the lung inflammatory cell infiltration, and capillary endothelial cell injury in hyperoxic lung injury in newborn rats. The mechanism may be related with the inhibition of MCP-1 and CINC-1 gene expression by EPO.</p>

Early clinical presentations and MRI characteristics in newborns with cerebral infarction / 中国当代儿科杂志

<p><b>OBJECTIVE</b>The present study aimed to characterize the clinical presentations and magnetic resonance imaging including conventional MRI and diffusion-weighted imaging (DWI) in newborns with cerebral infarction.</p><p><b>METHODS</b>Clinical records of 16 newborn infants with cerebral infarction were reviewed. All cases underwent DWI examination in addition to conventional MRI examination [T1-weighted (T1W) and T2-weighted (T2W)]within 5 days after birth. Five patients received the second MRI examination at the age of 11 to 18 days.</p><p><b>RESULTS</b>Eight patients had antenatal risk factors, 9 had intranatal risk factors, and no postnatal risk factors were found. Seizures as the first symptom were noted in 11 neonates, with a short duration and a low frequency. The first imaging examination (within 5 days) showed a slight hypointensity on T1W, a slight hyperintensity on T2W and significantly increased signal intensity with a clear boundary on DWI in the lesions. In the MRI re-examination, more obvious hypointensity on T1W and hyperintensity on T2W were noted, while hypointensity was shown on DWI in the lesions compared with the first imaging results.</p><p><b>CONCLUSIONS</b>Seizures characterized by short duration and low frequency usually may be the first symptom in newborns with cerebral infarction. A hyperintensity on DWI was shown in the lesions at the early stage of neonatal cerebral infarction. A hypointensity on T1W and a hyperintensity on T2W were demonstrated in the lesions with increasing disease duration.</p>

Expression of HoxB5 mRNA and their effect on lung development in premature rats with hyperoxia-induced chronic lung disease / 中华儿科杂志

<p><b>OBJECTIVE</b>Resolution of alveolar damage after lung injury requires finely orchestrated processes that include coordinated and effective tissue reconstruction to reestablish a functional barrier. Reconstitution of denuded type I alveolar epithelial cell that undergo apoptotic and necrotic death after lung injury is required in many pulmonary diseases. Disruption of distal airway development and type II-type I alveolar epithelial cell differentiation after lung injury and disordered repair of the alveolus after injury is one of the predominant pathological characteristics of chronic lung disease (CLD) of premature infants. HoxB5 belongs to the Hox gene family encoding transcription factors known for their role in skeletal patterning and the elaboration of organs. HoxB5 is required for embryonic respiratory tract morphogenesis. The present study aimed to test the hypothesis that HoxB5 may participate in the etiology of CLD and to understand possible mechanism.</p><p><b>METHODS</b>Premature rat pups were taken out surgically at gestational age 21 d. CLD was induced by hyperoxia exposure in neonatal premature rats. Eighty premature rats were randomly exposed to hyperoxia (FiO2 = 0.90, CLD group) and to room air (FiO2 = 0.21, control group) (n = 40 each). Lung specimens were obtained respectively on days 1, 3, 7, 14 and 21 after exposure. Histopathologic changes was assayed after hematoxylin and eosin (HE) staining and pulmonary development was evaluated by lung coefficient and radical alveolar counts (RAC), dynamic changes of RAC were observed; and the expression of HoxB5, AQP-5, and SP-B mRNA were assayed by reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>There were no significant differences in the RAC and the expression level of HoxB5, AQP-5, and SP-B mRNA between the CLD and the control groups within 3 days after birth (P > 0.05). However, compared to the control group, the RAC of the CLD group was reduced (6.35 +/- 0.83 vs. 7.67 +/- 0.52), and the expression of HoxB5 (0.98 +/- 0.14 vs. 1.20 +/- 0.16), AQP-5 (0.78 +/- 0.11 vs. 1.04 +/- 0.19) mRNA were significantly lower (P < 0.05), while the expression of SP-B mRNA was increased on the 7th day (P < 0.05). On the 14th day, the RAC and the expression of HoxB5, AQP-5 mRNA of CLD group were significantly lower than those of the control group (P < 0.05), and the expression of SP-B mRNA continued to increase (P < 0.05). On the 21st day, the expression of HoxB5, AQP-5 mRNA decreased to the nadir (0.64 +/- 0.11 vs. 1.18 +/- 0.13 and 0.67 +/- 0.12 vs. 0.97 +/- 0.01, respectively) (P < 0.01), on the same day the expression of SP-B mRNA reached to the pinnacle (1.43 +/- 0.07 vs. 1.12 +/- 0.09) (P < 0.01). The expression of HoxB5 mRNA was positively correlated with RAC in the CLD group (r = 0.685, P < 0.01).</p><p><b>CONCLUSIONS</b>With hyperoxia exposure, the mRNA expression of specific marker of type I alveolar epithelial cell, AQP-5, was decreased while specific marker of type II alveolar epithelial cell, SP-B, was increased; and the expression of HoxB5 mRNA in lung tissues kept on decreasing. Decreased expression of HoxB5 may associate with the disruption of type II-I alveolar epithelial cell differentiation and thus may play an important role in inhibition of lung development with CLD. The altered Hox gene expression may predispose lung pathology.</p>

Effect of position on oxygenation in neonates after weaning from mechanical ventilation / 中国当代儿科杂志

<p><b>OBJECTIVE</b>What is the best suitable position for neonates who were weaned from mechanical ventilation has not been identified. This study aimed to evaluate the effect of the supine and prone positions on oxygenation in neonates within 6 hrs after weaning from mechanical ventilation.</p><p><b>METHODS</b>Sixty neonates who were weaned from mechanical ventilation were randomly given prone or supine position (n=30 each). They all received oxygen inspiration and SPO2 was maintained in a normal range by adjusting the oxygen flow rate (FiO2). Blood PaO2 and PaCO2 levels were measured 1 and 6 hrs after weaning and then the alveolodouble ended arrowarterial oxygen partial pressure difference (A-aDO2), respiratory index and oxygenation index were calculated.</p><p><b>RESULTS</b>Mean FiO2 used in the prone position group was significantly lower than that in the supine position group 1 and 6 hrs after weaning (P<0.01). The value of A-aDO2 in the prone position group 1 hr (171.06+/-86.55 vs 253.62+/-71.56; P<0.01) and 6 hrs after weaning (105.85+/-78.18 vs 208.48+/-86.80; P<0.01) were significantly lower than that in the supine position group. The respiratory index in the prone position group 1 and 6 hrs after weaning (2.16+/-1.24 and 1.35+/-1.11) was also reduced compared to 3.74+/-1.68 and 3.65+/-1.28 in the supine position group (P<0.01). In contrast, PaO2 in the prone position group 1 hr (88.70+/-32.65 vs 73.43+/-17.68; P<0.01) and 6 hrs (84.10+/-13.95 vs 70.20+/-20.27; P<0.01) after weaning was significantly higher than that in the supine position group. The oxygenation index in the prone position group 1 and 6 hrs after weaning (213.49+/-88.96 and 275.23+/-108.83) increased significantly compared to 141.54+/-43.25 and 160.62+/-63.03 in the supine position (P<0.01).</p><p><b>CONCLUSIONS</b>The prone position is better than the supine position for the improvement of oxygenation within 6 hrs after weaning from mechanical ventilation in neonates.</p>

Clinical evaluation of neonatal hypoglycemic brain injury demonstrated by serial MRIs / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the relationship between clinical and imaging features in neonates with hypoglycemic brain injury.</p><p><b>METHODS</b>Sixteen neonates with hypoglycemic brain injury received a MRI scan with the sequences of T1WI, T2WI and DWI within 48 hrs after admission. Of the 16 patients, 11 received second MRI scan at two weeks of their lives, and 3 received a third scan at ages of 1-5 months.</p><p><b>RESULTS</b>Repeated seizures, lethargy and hypotonia were common clinical manifestations. Five severe hypoglycemia cases presented coma, respiratory failure and even cardiorespiratory arrest. The minimum mean value of whole blood glucose (WBG) in the 16 patients was 0.98+/-0.43 mmol/L, and that of the 5 severe cases was 0.72+/-0.42 mmol/L. EEG showed intermittent low voltage in the mild hypoglycemia cases. Flatten pattern and even electrocerebral silence was noted in the severe cases. Occipital and parietal cortexes (OPC) injuries were found in all of the 16 patients and 2 patients had concurrent periventricular white matter injury. A widespread involvement of cortex was found in the 5 severe hypoglycemia cases in which 1 showed widespread involvement of white matter, and 2 showed involvement of basal ganglia and thalamus. The 5 patients with widespread cortex injury and the 2 patients with OPC and periventricular white matter injury showed lower minimum WBG levels compared with those with OPC alone (0.71+/-0.35 mmol/L vs 1.19+/-0.42 mmol/L; t= 2.4124, P<0.05). The appearance of high-intensity signals on DWI was shown as early changes of signals in all of the 16 patients. The second MRI scan for 7 patients with OPC showed abnormal signals on T1WI and T2WI in 5 patients and abnormal signals on DWI in 3 cases. Cerebral atrophy and multicystic encephalomalacia were found in four patients with widespread involvement of cortex on DWI. In the follow-up one patient with OPC presented delayed myelination and one with concurrent white matter injury showed spastic diplegia. One patient with widespread involvement of cortex showed diffused encephalomalacia.</p><p><b>CONCLUSIONS</b>The severity of hypoglycemic brain injury demonstrated by serial MRIs relates to the severity of hypoglycemia. The occipital and parietal areas are the most vulnerable following hypoglycemia in neonates. Severe hypoglycemic brain injury manifests as a widespread involvement of cortex, or combined with white matter, or basal ganglia and thalamus. DWI can show early hypoglycemic brain injury.</p>

Changes of u-PA and PAI-1 expression in the lung tissue of neonatal rats after inhaling high concentration oxygen / 中华儿科杂志

<p><b>OBJECTIVE</b>Arrested lung development and lung fibrosis are characteristic pathological changes in chronic lung disease (CLD). Therefore, the role of extracellular matrix (ECM) remodeling in lung fibrosis has been emphasized recently. Plasmin system is also an important factor to modulate ECM degradation and matrix metalloproteinase (MMP) system. In this study, the authors established an animal model of CLD induced by inhaling high concentration oxygen (hyperoxia) to investigate the changes and functions of urokinase-plasminogen activator (u-PA) and plasminogen activator inhibitor-1 (PAI-1) in CLD.</p><p><b>METHODS</b>Full-term newborn rats were continuously exposed to oxygen (0.90 - 0.95 O(2)) or room air within 12 h after birth. On day 1, 3, 7, 14, 21 in hyperoxia groups and air controls, lung pathology in newborn rats were observed. The changes of u-PA and PAI-1 protein and mRNA expression were measured by Western blotting and RT-PCR.</p><p><b>RESULTS</b>(1) The pathological findings of the lung tissue: on day 3, there was a few inflammatory cells exuded out, bleeding, edema, and interstitial cells increased in hyperoxia group. On day 7 and thereafter, the terminal air space size of the oxygen-exposed rat became large, there was inflammatory response and more interstitial cells, interstitium was thicker, and collagen deposited. (2) u-PA expression: On day 3, the u-PA protein expression increased in hyperoxia group compared with controls (115.52 +/- 7.10 vs. 96.51 +/- 6.33), P < 0.01. On day 7 to day 21, u-PA protein expression (97.66 +/- 7.98, 99.91 +/- 7.60, 103.23 +/- 6.24) was lower than in the control groups (112.43 +/- 6.01, 123.25 +/- 8.35, 103.23 +/- 6.24), P < 0.05, < 0.01 and < 0.01, respectively. u-PA mRNA increased on d 3 in hyperoxia group compared with controls (1.18 +/- 0.07 vs. 0.99 +/- 0.05), P < 0.01. On d 7 to 21, mRNA expression (1.01 +/- 0.06, 1.10 +/- 0.12, 1.27 +/- 0.06) was lower than that in the controls (1.15 +/- 0.08, 1.51 +/- 0.32, 1.60 +/- 0.24) too, P < 0.01. (3) PAI-1 expression: From d 7 to 21 of oxygen exposure, PAI-1 protein expression (147.83 +/- 12.27, 149.07 +/- 11.17, 161.42 +/- 13.08) increased compared with the controls (116.18 +/- 10.67, 113.73 +/- 15.58, 126.60 +/- 8.59), P < 0.01, < 0.05 and < 0.01, respectively. mRNA expression (1.49 +/- 0.28, 1.46 +/- 0.31, 1.51 +/- 0.33) increased compared with the control group (0.94 +/- 0.01, 0.94 +/- 0.03, 0.98 +/- 0.03), P < 0.05, < 0.01 and < 0.05, respectively.</p><p><b>CONCLUSIONS</b>In the early stage of hyperoxic exposure, the balance of u-PA/PAI-1 mRNA and protein increased, plasmin and degradation activity increased, which may increase the degradation of ECM in lung base membrane. During the middle and late stage, the expression of u-PA/PAI-1 mRNA and protein decreased, plasmin and degradation activity were lower, in parallel to thicker interstitium, suggesting that the imbalance of u-PA/PAI-1 may also play a role in lung fibrosis in CLD induced by hyperoxia.</p>

Values of diffusion-weighted magnetic resonance imaging in the early detection of periventricular leukomalacia in preterm infants / 中华儿科杂志

<p><b>OBJECTIVE</b>Periventricular leukomalacia (PVL), the principal form of brain injury in the premature infant, is characterized by overt focal necrotic lesions in periventricular white matter and diffuse cerebral white matter injury. The early detection of the disease is not consistently possible with cranial ultrasonography or conventional magnetic resonance imaging (MRI). Recently, diffusion-weighted imaging (DWI) has been shown to be highly sensitive in detecting acute ischemic cerebral injury. This study aimed to evaluate possible role of DWI in early diagnosis of PVL.</p><p><b>METHODS</b>Images and clinical data from 12 preterm infants with PVL diagnosed in our NICU from August, 2005 to April, 2007 were reviewed. MRI using conventional and diffusion-weighted imaging, as well as the assays of blood routine test, serum bilirubin, C-reactive protein (CRP), blood culture, blood gas analysis, blood sugar and serum ions were performed in these preterm infants. All examinations were performed on a 3.0-T MRI system (Philips Intera Acheva Magnetom Vision) with echo-planar imaging capability with the use of a standard protocol. The imaging protocol for all the patients contained diffuse weighted images (EPI-SE, TR = 2144 ms, TE = 56 ms), T1-weighted images (TR = 389 ms; TE = 15 ms; slice thickness = 4 mm) as well as T2-weighted images (TR = 3035 ms; TE = 100 ms; slice thickness = 4 mm). The first MR examinations were performed in all these twelve preterm infants (mean age 4.5 days, range 2 - 7 days). Conventional MRI and DWI sequences obtained in the acute phase were compared. All the neonates underwent another two MRI examinations up to 2 and 4 weeks after delivery; five subjects also underwent MRI follow-up for up to 4 - 8 months (in 3 for 4 months, in 1 for 7 months, and in another for 8 months). Qualitative evaluations were performed to assess the presence of DWI changes compatible with PVL.</p><p><b>RESULTS</b>The gestational ages of these twelve patients were from 31 to 35 weeks. None of them had intrauterine distress or birth asphyxia. None of the patients had localized neurological signs in the early course except for abnormal muscular tone of some extent, but seizure and apnea were their major symptoms. No other positive signs of nervous system was found in these preterm infants with PVL. First DWI detection (on the average of 4.5 days) in all these infants showed bilateral, symmetric, diffuse high signal intensity (including genu and plenum of corpus callosum), while conventional MRI showed normal images on both T1- and T2-weighted imaging; two weeks later, DWI showed irregularly high, low mixed signals while conventional MRI showed punctate high signal intensity on T1-weighted imaging and slightly lower signal on T2-weighted imaging. Four weeks later, DWI showed cystic low signal intensity where conventional MRI showed low signal intensity on T1-weighted imaging and high signal intensity on T2-weighted imaging (cystic PVL). Four months later, DWI showed that the cystic cava became diminished and disappeared, while conventional MRI showed reduced cerebral white matter and dilation of ventricle.</p><p><b>CONCLUSION</b>Bilateral, symmetric, diffuse high signal intensity on DWI seems to be the earliest evidence of PVL; diffusion-weighted imaging performed in the acute phase of the disease may have a higher correlation with later evidence of PVL than does conventional MR imaging. DWI is likely to be a considerable technique in the early assessment of white matter injury and later PVL in preterm infants.</p>

Early assessment of severe hypoxic-ischemic encephalopathy in neonates by diffusion-weighted magnetic resonance imaging techniques and its significance / 中华儿科杂志

<p><b>OBJECTIVE</b>Hypoxic-ischemic encephalopathy (HIE) is an important cause of morbidity and mortality in the neonates. Early and accurate diagnosis is helpful not only for assessing prognosis but also for making treatment decisions. The aim of this study was to explore the value of early assessment of HIE by applying the diffusion-weighted imaging (DWI) in acute (within 72 hours), subacute or chronic stages of HIE in comparison to conventional magnetic resonance imaging (MRI) in clinical practice.</p><p><b>METHODS</b>Images and clinical charts of fourteen term neonates with clinically diagnosed severe hypoxic-ischemic encephalopathy treated in the NICU from January 2006 to February 2007 were retrospectively reviewed. Inclusion criteria were: term infant (37 approximately 42 weeks) and high clinical suspicion of severe HIE (low Apgar scores, need for resuscitation, metabolic acidosis, acute encephalopathy (eg, hypotonia, coma, seizures). All examinations were performed on a 3.0-T MRI system (Philips Intera Acheva Magnetom Vision) with echo-planar imaging capability with the use of a standard protocol. The imaging protocol for all the patients contained diffuse weighted images (EPI-SE, TR = 2144 ms, TE = 56 ms), T1-weighted images (TR = 389 ms; TE = 15 ms; slice thickness = 4 mm) as well as T2-weighted images (TR = 3035 ms; TE = 100 ms; slice thickness = 4 mm). The studies were first performed within 72 hours of life in these 14 consecutive patients, including both standard T1, T2-weighted image and DWI; follow-up MR studies were performed for 4 patients at the ages of 7 days, for 4 at 14 days, for another 3 at ages of both 21 days and 8 months.</p><p><b>RESULTS</b>First inspection (on an average of 48 hours after birth): routine T1, T2-weighted images showed normal images in all patients, while diffusion images showed symmetric high intensity signal in the lateral thalami and posterior limbs of internal capsules (PLIC). Following up: on day 7, routine MRI showed both symmetric T1 prolongation and T2 slightly shortening in lateral thalami, DWI showed abnormal high signal intensity in bilateral basal ganglion (mainly in the back site of lentiform nuclei, putamen) and the cortex around central sulcus, but the previous hyperintensity in lateral thalami and PLIC disappeared. On day 14, routine MRI showed symmetric T1 prolongation, T2 shortening in bilateral thalami, lentiform nuclei and cortex around central sulus. On day 21, routine MRI showed T1 prolongation, T2 shortening in bilateral thalami and basal ganglion while previously obvious PLIC disappeared, whereas DWI showed normal images. Eight months later, deeper cerebral sulus, dilation of ventricles and widening of extracerebral space were shown.</p><p><b>CONCLUSION</b>Diffusion-weighted imaging has proved more sensitive than conventional MR imaging sequences in detecting acute cerebral infarction in adult subjects. DWI is proposed as a method for early detection of hypoxic-ischemic brain injury. In this study, DWI showed the same focus (lateral thalami and PLIC) and similar extent of the injury in these severe HIE patients in the early stage after birth (in 72 hours). The sites which showed hyperintensive signals in DWI were consistent with the foci in subsequent follow-up by routine MRI. Thus, DWI is supposed to be a technique for early assessment of the extent of hypoxic-ischemic brain injury and the prognosis in clinic. Though DWI is superior to the other imaging modalities in detecting ischemia, diffusion restriction is not necessarily indicative of permanent damage. The abnormal image on DWI may not last long. However, in chronic stage, the follow-up conventional MRI may compensate the inadequacy of DWI.</p>

Expression and roles of CDK4 and p21 in lung tissues of premature rats with hyperoxia-induced chronic lung disease / 中国当代儿科杂志

<p><b>OBJECTIVE</b>The pathogenic mechanisms of chronic lung disease (CLD) of premature infants are not fully understood. Its final pathological changes have been shown to relate with lung cell proliferation. The aim of the study was to explore the relationship of the expression of cyclin dependent kinase 4 (CDK4) mRNA and cyclin dependent kinase inhibitor (CDKI) p21 mRNA with lung cell proliferation.</p><p><b>METHODS</b>Eighty premature rats were randomly assigned to a hyperoxia group and a control group (n=40 each). The hyperoxia group was exposed to high concentration of oxygen (FiO2 >0.90 and developed CLD. The control group was exposed to room air (FiO2 =0.21). The rats were randomly subdivided into groups sacrificed at 1, 3, 7, 14 and 21 days of exposure. Lung tissues were collected and made into 5 microm sections. Expression of proliferating cell nuclear antigen (PCNA) in lung tissues was detected by immunohistochemistry. Dynamic expression of CDK4 mRNA and p21 mRNA were detected by in situ hybridization. Lung histomorphology and fibrosis were observed by microscopy.</p><p><b>RESULTS</b>Expression of PCNA and CDK4 mRNA of lung cells in the hyperoxia group increased significantly after 7 days of exposure, and further increased after 14 and 21 days compared with controls. p21 mRNA expression in the hyperoxia group significantly increased after 1 and 3 days of exposure. After 7 days, p21 mRNA expression progressively decreased, but remained at a higher level than control through 21 days of exposure. PCNA expression was positively correlated to CDK4 mRNA expression (r=0.83, P < 0.05) and negatively correlated to p21 mRNA expression (r=-0.81, P < 0.05) in the hyperoxia group between 7 and 21 days of exposure.</p><p><b>CONCLUSIONS</b>Hyperoxia can induce lung cell proliferation in premature rats. The over-expression of CDK4 gene and the decreased expression of p21 gene in lung tissues may be associated with lung cell proliferation induced by hyperoxia.</p>

Effect of losartan on lung fibrosis in neonatal rats with hyperoxia-induced chronic lung disease / 中国当代儿科杂志

<p><b>OBJECTIVE</b>In addition to regulating blood pressure, angiotensin II is involved in lung fibrogenesis. This study aimed to explore the effect of losartan, an angiotensin II type 1 receptor antagonist, on lung fibrosis in neonatal rats with hyperoxia-induced chronic lung disease (CLD) and its possible mechanisms.</p><p><b>METHODS</b>Neonatal Wistar rats were randomly divided into four groups within 24 hrs after birth: room air exposure, hyperoxia exposure (85%-90% O2), hyperoxia exposure + losartan, and hyperoxia exposure + placebo. Losartan (5 mg/kg/d) or placebo was administered beginning on the 6th day after birth. After 7, 14 and 21 days of exposure, 8 rats in each group were sacrificed. Lung histological changes were evaluated by hematoxylin-eosin staining. Levels of hydroxyproline (HYP), superoxide dismutase (SOD) and malondialdehyde (MDA) in lung tissues were determined by spectroscopy.</p><p><b>RESULTS</b>Hyperoxia exposure resulted in decreased alveolar septation, enlarged terminal air space, increased collagen deposition, pulmonary hemorrhage, and pulmonary consolidation. In the hyperoxia exposure + losartan group, the alveolar septum became thinner and lung fibrosis was alleviated, but the alveolar space was not obviously deflated and the number of secondary septum was not increased. Hyperoxia exposure increased significantly the HYP contents in lung tissues 14 and 21 days after exposure. Addition of losartan to the hyperoxia exposure resulted in decreased HYP contents (471.46 +/- 30.63 mu g/kg vs 545.15 +/- 34.90 mu g/kg for hypoxia alone; P < 0.01) after 21 days of exposure. SOD activity increased 7 days after hyperoxia exposure and then decreased to levels similar to the air exposure group. MDA levels increased to a peak at 7 days and remained at higher levels through 21 days of exposure when compared with the air exposure group (P < 0.01). Losartan treatment significantly increased SOD activities (82.94 +/- 4.62 U/mg protein vs 67.78 +/-8.02 U/mg protein; P < 0.01) and decreased MDA levels (30.54 +/- 5.89 nmol/mg protein vs 48.75 +/- 8.09 nmol/mg protein, P < 0.01) compared with the hyperoxia exposure group 21 days after exposure.</p><p><b>CONCLUSIONS</b>Losartan attenuated lung fibrosis in neonatal rats with hyperoxia-induced CLD, possibly through an increase of antioxidase enzyme activity and reduction of lipid peroxidation.</p>