Real world study (RWS) has attracted more and more attention of neonatologists since it involves less clinical intervention and is closer to actual clinical conditions. Generally speaking, RWS means to select treatment measures based on the internal efficacy and safety verified by randomized controlled trials (RCTs), more representative samples, and patients' actual conditions and their guardians' will and conduct follow-up evaluation of short-and long-term outcomes, in order to further evaluate the external efficacy and safety of interventional measures. Most guidelines for clinical practice are based on RCTs and lack the support of real world data. Strengthening of neonatal RWS helps to make these guidelines more practical and thus promotes the development of neonatal medicine.

Objective To study the risk factors for elevated serum total bile acid (TBA) in preterm infants. Methods A retrospective analysis was performed for the clinical data of 216 preterm infants who were admitted to the neonatal intensive care unit. According to the presence or absence of elevated TBA (TBA > 24.8 μmol/L), the preterm infants were divided into elevated TBA group with 53 infants and non-elevated TBA group with 163 infants. A univariate analysis and an unconditional multivariate logistic regression analysis were used to investigate the risk factors for elevated TBA. Results The univariate analysis showed that there were significant differences between the elevated TBA group and the non-elevated TBA group in gestational age at birth, birth weight, proportion of small-for-gestational-age infants, proportion of infants undergoing ventilator-assisted ventilation, fasting time, parenteral nutrition time, and incidence of neonatal respiratory failure and sepsis (P < 0.05). The unconditional multivariate logistic regression analysis showed that low birth weight (OR=3.84, 95% CI:1.53-9.64) and neonatal sepsis (OR=2.56, 95% CI:1.01-6.47) were independent risk factors for elevated TBA in preterm infants. Conclusions Low birth weight and neonatal sepsis may lead to elevated TBA in preterm infants.

Objective To evaluate the relationship of vitamin D level with the development of necrotizing enterocolitis (NEC) in preterm infants. Methods A total of 429 preterm infants with a gestational age of < 36 weeks, who were admitted to the department of neonatology within 2 hours after birth between January and December, 2016, were enrolled in the study. According to whether these infants developed NEC, the 429 subjects were divided into NEC group (n=22) and non-NEC group (n=407). Peripheral venous blood was collected from these preterm infants and their mothers at admission to measure the level of 25-hydroxyvitamin D (25-OHD). The two groups were compared in terms of the serum 25-OHD levels of preterm infants and their mothers. Pearson correlation analysis was used to investigate the correlation between the serum 25-OHD levels of preterm infants and their mothers. The distribution of vitamin D levels in preterm infants was compared between the two groups. The univariate logistic regression analysis was used to determine the risk factors for NEC in preterm infants. Results The serum 25-OHD levels of preterm infants and their mothers in the NEC group were significantly lower than in the non-NEC group (P < 0.001). In both groups, the serum 25-OHD levels of mothers and preterm infants were positively correlated with each other (P < 0.001). The distribution of vitamin D levels (normal vitamin D level, low vitamin D level, vitamin D deficiency, and severe vitamin D deficiency) was significantly different between the NEC and non-NEC groups (P < 0.001). The univariate logistic regression analysis showed that gestational age, birth weight, 25-OHD levels of preterm infants and their mothers, the duration of mechanical ventilation, the duration of oxygen inhalation, and the length of hospital stay were associated with the development of NEC (P < 0.05). Conclusions The serum 25-OHD levels of preterm infants and their mothers may be related to the development of NEC in preterm infants, suggesting that vitamin D supplementation during pregnancy is important for preventing the development of NEC in preterm infants.

Objective To establish the intrauterine growth percentile curves of full-term neonates with different gestational ages (GAs) born to primiparous or multiparous women, and to investigate the influence of parity on intrauterine growth potential. Methods Cross-sectional cluster sampling was performed from April 2013 to September 2015 to measure physical growth in full-term singleton infants with a GA of 37-41 weeks in two hospitals in Shenzhen, China. The Lambda-Mu-Sigma method was used for curve fitting. Results The mean values of birth weight, body length, head circumference, chest circumference, and crown-rump length were obtained in 14 529 full-term infants. The 10th, 25th, 50th, 75th, and 90th percentile curves of the five indices were established. The full-term infants born to multiparous women had similar patterns and growth trends of the five percentile curves of the above five indices to those born to primiparous women, while the full-term infants with a GA of 37-41 weeks born to multiparous women had higher mean values and percentile curve values of the above five indices than those born to primiparous women. In the group with a GA of 41 weeks, there was no significant difference in the crown-rump length between the infants born to primiparous women and those born to multiparous women, but there were significant differences in the means of the above five indices in all the other GA groups between the two group infants (P < 0.05). Conclusions Full-term infants with a GA of 37-41 weeks born to multiparous women have higher intrauterine growth levels of birth weight, body length, head circumference, chest circumference, and crown-rump length than those born to primiparous women, suggesting that parity is an important influencing factor for intrauterine growth potential.

Objective To investigate the nutritional status of children on maintenance hemodialysis due to stage 5 chronic kidney disease (CKD) and the clinical significance of nutritional assessment indices. Methods A total of 21 children on maintenance hemodialysis due to stage 5 CKD were grouped according to body mass index. The nutritional status was assessed based on anthropometric parameters, biochemical parameters, inflammatory factors, residual renal function, indices of dialysis adequacy, and resting energy expenditure. Related indices were compared between the children with malnutrition and those with normal nutritional status. Results Of the 21 children, 10 had malnutrition and 11 had normal nutritional status. There were significant differences between the two groups in anthropometric parameters, levels of leptin, insulin-like growth factor-1, interleukin-1, interleukin-6, and tumor necrosis factor-α, and mean 24-hour residual urine volume (P < 0.05), while there were no significant differences in albumin, prealbumin, cholesterol, urea clearance index (Kt/V), and measured resting energy expenditure. Conclusions Anthropometric parameters, biochemical parameters, residual renal function, and inflammatory factors have an important value in evaluating the nutritional status of children with stage 5 CKD on maintenance hemodialysis. Further studies are needed to investigate the value of the measurement of resting energy expenditure in the evaluation and monitoring of nutritional status in children with stage 5 CKD on maintenance hemodialysis.

Objective To investigate the current status of vitamin A deficiency in preschool children in Dongguan, China, as well as the effect of vitamin A on serum ferritin, red blood cell, and reticulocyte parameters. Methods Cluster sampling was performed from April 2015 to December 2016 to select 2 085 preschool children (3-6 years old) without any disease in Dongguan. Routine blood test, reticulocyte count, serum ferritin measurement, hemoglobin electrophoresis, and vitamin A measurement were performed for all children. The associations of age and sex with vitamin A and serum ferritin concentrations were analyzed. The effect of vitamin A concentration on serum ferritin, red blood cell, and reticulocyte parameters and the effect of reduced iron storage caused by vitamin A deficiency on red blood cell parameters were evaluated. Results Of the 2 085 children, 140 (6.71%) had reduced iron storage, and 678 (32.52%) had vitamin A deficiency. Among the 678 children with vitamin A deficiency, 647 (95.4%) had subclinical deficiency and 31 (4.6%) had clinical deficiency. There was no significant difference in vitamin A concentration between boys and girls, however girls had a significantly higher serum ferritin concentration than boys (P < 0.05). The clinical vitamin A deficiency group had a significantly higher serum ferritin concentration than the subclinical vitamin A deficiency group and the normal group (P < 0.05). In cases of vitamin A deficiency, the reduced iron storage group had significant reductions in mean corpuscular volume and mean corpuscular hemoglobin than the normal iron storage group (P < 0.05). Compared with the normal vitamin A group, the vitamin A deficiency group had significantly lower hemoglobin concentration, mean corpuscular hemoglobin, red blood cell count, hematocrit, absolute reticulocyte count, reticulocyte percentage, and reticulocyte hemoglobin content, as well as a significantly higher mean corpuscular volume (P < 0.05). Conclusions Vitamin A deficiency is prevalent in preschool children in Dongguan, China, and it may adversely affect serum ferritin, red blood cell, and reticulocyte parameters.

Objective To investigate the percentages of peripheral blood γδ T cells and regulatory T cells (Treg) and the expression of associated cytokines, interleukin 17 (IL-17) and transforming growth factor-β1 (TGF-β1), in infants with human cytomegalovirus (HCMV) infection. Methods Twenty-two infants with HCMV infection (HCMV group) and 22 healthy infants who underwent physical examination (control group) were enrolled in this study. The percentages of peripheral blood γδ T cells and Treg cells were determined by flow cytometry. The levels of IL-17 and TGF-β1 in plasma were measured using ELISA. Results Compared with the control group, the HCMV group had significantly higher percentage of γδ T cells and IL-17 level (P < 0.01) and significantly lower percentage of Treg cells and TGF-β1 level (P < 0.01). In the HCMV group, the percentage of γδ T cells was negatively correlated with the percentage of Treg cells and TGF-β1 level (P < 0.05), but positively correlated with IL-17 level (P < 0.05); the percentage of Treg cells was positively correlated with TGF-β1 level (P < 0.05), but negatively correlated with IL-17 level (P < 0.05); there was no correlation between IL-17 level and TGF-β1 level (P > 0.05). Conclusions There is an imbalance between γδ T cells and Treg cells in the peripheral blood of infants with HCMV infection, and γδ T cells may be involved in the secretion of IL-17.

Objective To study the difference in expression of TOPK/PBK in lymph nodes between children with malignant lymphoma and those with reactive lymphoid hyperplasia. Methods Eighty children with malignant lymphoma and twenty children with reactive lymphoid hyperplasia were enrolled as subjects. Immunohistochemistry was used to determine the expression of TOPK/PBK in all the subjects. The expression of TOPK/PBK was compared between the two groups. Results The TOPK/PBK-positivity rate was significantly higher in children with malignant lymphoma than in those with reactive lymphoid hyperplasia (P < 0.05). There was no significant difference in the TOPK/PBK-positivity rate between the children with Hodgkin's lymphoma and non-Hodgkin's lymphoma (NHL). There were significant differences in the TOPK/PBK-positivity rate among children with different pathological types of NHL (P < 0.05):the children with lymphoblastic lymphoma showed the highest TOPK/PBK-positivity rate and those with mature B-cell lymphoma and mature T/NK-cell lymphoma had a similar TOPK/PBK-positivity rate. Conclusions The expression of TOPK/PBK is up-regulated in the lymph nodes of children with malignant lymphoma. The expression level of TOPK/PBK may be related to the pathological type of NHL.

Objective To investigate the main risk factors for asthma in Chinese children, and to provide a reference for the prevention and treatment of asthma. Methods The databases including CNKI, Wanfang Data, China Biology Medicine disc, VIP Database for Chinese Technical Periodicals, Web of Science, and PubMed were searched for studies on risk factors for asthma in Chinese children published up to September 2017. Stata 12.0 was used for the Meta analysis. Results A total of 24 case-control studies were included, with 5 309 cases in the case group and 6 404 cases in the control group. The Meta analysis showed that a family history of asthma (OR=5.246, 95% CI:3.435-8.011), a family history of allergy (OR=4.627, 95% CI:2.450-8.738), atopic constitution (OR=4.659, 95% CI:2.511-8.644), allergic rhinitis (OR=11.510, 95% CI:6.769-19.574), a history of eczema/dermatitis (OR=4.919, 95% CI:3.514-6.886), a history of allergies (OR=4.732, 95% CI:2.802-7.989), a history of food allergies (OR=5.890, 95% CI:3.412-10.166), a history of drug allergies (OR=4.664, 95% CI:2.637-8.252), mold contamination at home (OR=2.483, 95% CI:1.671-3.690), flowers at home (OR=1.748, 95% CI:1.383-2.209), a history of house decoration (OR=2.823, 95% CI:2.206-3.935), and cesarean section (OR=1.894, 95% CI:1.166-3.077) were risk factors for asthma in children, while breastfeeding was a protective factor against asthma (OR=0.508, 95% CI:0.396-0.653). Conclusions The development of asthma in Chinese children is associated with a variety of factors, among which a family history of asthma, a family history of allergy, atopic constitution, a history of allergies, allergic comorbidities, cesarean section, and bad family environment can increase the risk of asthma in children, while breastfeeding can reduce the risk.

Objective To study the effect of Bifidobacterium on the expression of β-defensin-2 (BD-2) in intestinal tissue of neonatal rats with necrotizing enterocolitis (NEC). Methods A total of 40 rats were randomly divided into four groups:normal control, Bifidobacterium control, NEC model, and Bifidobacterium treatment, with 10 rats in each group. A rat model of NEC was induced by hypoxia, cold stimulation, and artificial feeding. The rats in the Bifidobacterium control and Bifidobacterium treatment groups were given Bifidobacterium via the gastric tube after cold stimulation once a day for three consecutive days. The morphological changes of the terminal ileum were observed under a light microscope and the intestinal injury score was determined. Immunohistochemistry and qRT-PCR were used to measure the protein and mRNA expression of BD-2 in the ileal mucosal tissue. Results The NEC model group had a significantly higher intestinal injury score than the normal control, Bifidobacterium control, and Bifidobacterium treatment groups (P < 0.05). The Bifidobacterium treatment group had a significantly higher intestinal injury score than the normal control and Bifidobacterium control groups (P < 0.05). The mRNA and protein expression of BD-2 in the normal control group was significantly lower than in the Bifidobacterium control, NEC model, and Bifidobacterium treatment groups (P < 0.05). The Bifidobacterium control group had significantly higher mRNA and protein expression of BD-2 than the NEC model and Bifidobacterium treatment groups (P < 0.05). The Bifidobacterium treatment group had significantly higher mRNA and protein expression of BD-2 than the NEC model group (P < 0.05). Conclusions Bifidobacterium can induce the expression of BD-2 in intestinal tissue of rats and reduce inflammatory response by increasing the expression of BD-2. This provides a protective effect on neonatal rats with NEC.

Objective To investigate the protective effect of prostaglandin E1 (PGE-1) against brain injury induced by hyperoxia in neonatal rats and observe the changes in the expression of glucose-regulated protein 78 (GRP78) and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), and to provide a theoretical basis for the clinical application of PGE-1 in the treatment of neonatal brain injury induced by hyperoxia. Methods Sixty neonatal Wistar rats were randomly divided into air control group, hyperoxic brain injury model group, and hyperoxic brain injury+PGE-1 group. All rats except those in the air control group were treated to establish a hyperoxic brain injury model. From the first day of modeling, the rats in the hyperoxia brain injury+PGE-1 group were intraperitoneally injected with PGE-1 2 μg/kg daily for 7 consecutive days, while the other two groups were treated with normal saline instead. The water content of brain tissue was measured; the pathological changes of brain tissue were evaluated by hematoxylin-eosin staining; the apoptosis of brain cells was assessed by nuclear staining combined with TUNEL staining; the protein expression of GRP78 and CHOP in brain tissue was measured by Western blot. Results The water content of brain tissue in the hyperoxic brain injury model group was significantly higher than that in the hyperoxic brain injury+PGE-1 group and air control group (P < 0.05); the water content of brain tissue in the hyperoxic brain injury+PGE-1 group was significantly higher than that in the air control group (P < 0.05). The pathological section of brain tissue showed inflammatory cell infiltration and mild cerebrovascular edema in the brain parenchyma in the hyperoxic brain injury model group; the periparenchymal inflammation and edema in the hyperoxic brain injury+PGE-1 group were milder than those in the hyperoxic brain injury model group. The apoptosis index of brain tissue in the hyperoxic brain injury model group was significantly higher than that in the hyperoxic brain injury+PGE-1 group and air control group (P < 0.05); the apoptosis index of brain tissue in the hyperoxic brain injury+PGE-1 group was significantly higher than that in the air control group (P < 0.05). The protein expression of GRP78 and CHOP in brain tissue was significantly higher in the hyperoxic brain injury model group than in the hyperoxic brain injury+PGE-1 group and air control group (P < 0.05); the protein expression of GRP78 and CHOP was significantly higher in the hyperoxic brain injury+PGE-1 group than in the air control group (P < 0.05). Conclusions PGE-1 has a protective effect against hyperoxia-induced brain injury in neonatal rats, which may be related to the inhibition of cell apoptosis by down-regulating the expression of GRP78 and CHOP.