A survey of neonatal births in maternity departments in urban China in 2005 / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the epidemiology of births in urban China.</p><p><b>METHODS</b>A retrospective study was conducted on neonates born in 2005 in the maternity departments of 72 urban hospitals from 22 provinces in China.</p><p><b>RESULTS</b>A total of 45722 infants born between January 1, 2005 and December 31, 2005 were enrolled. The male to female sex ratio was 1.13:1. Preterm births accounted for 8.1%. The incidence of very low birth weight infants was 0.7%. A total of 99.7% of mothers delivering at term had conceived naturally and 0.3% had experienced assisted reproduction. A total of 98.4% of mothers who delivered preterm had conceived naturally and 1.6% had experienced assisted reproduction. The proportion of vaginal deliveries was 50.8% compared to 49.2% delivered by cesarean sections. Many cesarean sections (38.1%) were due to social factors. Infants with an Apgar score≤7 at 1 minute accounted for 4.8%, and 1.6% of infants had an Apgar score≤7 at 5 minutes. Of all the infants included in the study, 7.14% were admitted to neonatal units for treatment. The death rate of all included infants was 0.74%.</p><p><b>CONCLUSIONS</b>The proportion of preterm births was higher in 2005 than in 2002-2003. The proportion of cesarean section deliveries was much higher in urban China than in most other Asian countries and America.</p>

An epidemiologic investigation of newborns from obstetric departments in the central south region of China / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the birth information of newborn infants from obstetric departments in the Central South Region of China.</p><p><b>METHODS</b>A retrospective investigation was carried out in 15582 newborns from obstetric departments of 23 hospitals in the Central South Region of China between January 1 and December 31 of 2005.</p><p><b>RESULTS</b>The sex ratio (male/female) of neonates was 1.16∶1. The proportion of preterm infants was 8.11%. The very low birth weight infants accounted for 0.73%. The neonates born by spontaneous labor accounted for 57.52%. Cesarean sections accounted for 40.82% (social factor of cesarean section: 29.91%). The incidence of neonatal asphyxia was 3.78%, in which 0.75% of the cases were severe asphyxia. The mortality of newborn infants was 0.55%, in which the mortality of preterm infants was 5.56%.</p><p><b>CONCLUSIONS</b>The proportion of preterm infants and the incidence of neonatal asphyxia is high in the Central South Region of China. The proportion of births delivered by cesarean section is high, and social factors are probably responsible for the high rate.</p>

Multicenter investigation for incidence of periventricular leukomalacia in premature infants in China / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Sponsored by the Subspecialty Group of Neonatology of Pediatric Society, China Medical Association, more than 10 large-scale hospitals participated in the near two-year multicenter investigation for brain injuries in premature infants in China. This study presented the investigation result for the incidence of periventricular leukomalacia (PVL) in premature infants from 10 Third Class A Level hospitals.</p><p><b>METHODS</b>The premature infants with a gestation age<37 weeks in the 10 hospitals were given routine cranial ultrasound scanning within seven days after birth, and then repeated every 3-7 days until discharge from January 2005 to August 2006. The severity of PVL was graded based on de Vries classification.</p><p><b>RESULTS</b>A total of 4 933 premature infants were enrolled. The total incidence of PVL and the incidence of cystic PVL were 2.3% (112/4 933) and 0.3% (16/4 933), respectively. Of the 112 PVL cases, 96 (85.7%) were with grade I, 14 (12.5%) with grade II, and 2 (1.8%) with grade III. The incidence of PVL in 4 maternal and child health care hospitals were significantly lower than that in 6 general or children's hospitals (1.4% vs 2.8%) (X2=10.284, P<0.01). Vaginal delivery and mechanical ventilation were possible high-risk factors for the development of cystic PVL.</p><p><b>CONCLUSIONS</b>The data of the multicenter investigation can basically reflect the situation about the occurrence of PVL in premature infants in major big cities of China. It is important to improve the ability to recognize the sonogram of non-cystic periventricular white matter injury.</p>

Protective effect of calpain inhibitor-3 on hypoxic-ischemic brain damage of neonatal rats / 中华儿科杂志

<p><b>OBJECTIVE</b>The mechanisms of hypoxic-ischemic brain damage (HIBD) are still largely unknown. Elevation of intracellular calcium concentration and subsequent calcium-dependent proteases activation such as calpains seem to play an important role in the process of neuronal death. Calpain inhibitors showed neuroprotective effects in adult rat cerebral ischemia models. This study aimed to investigate the protective effect and associated mechanisms of calpain inhibitor-3 (MDL28170) on HIBD of neonatal rats.</p><p><b>METHODS</b>Seven-day old Sprague-Dawley rats were randomly divided into three groups: the control group (n = 18), HIBD group (n = 48) and calpain inhibitor-3 treated group (MDL group, n = 48). The mice in the latter two groups were subjected to hypoxia-ischemia (HI) insult. The puppies in MDL group were intraperitoneally injected with MDL28170 (25 mg/kg) at 0, 2 and 4 h after HI, while those in the other two groups were intraperitoneally injected with normal saline instead. All the pupies were sacrificed at 6 h, 24 h and 72 h after HI. Quantitative real-time fluorescent polymerase chain reaction was employed to detect micro-calpain gene expression, immunoblotting technique was used to measure mu-calpain and caspase-3 protein activation, apoptosis of ipsilateral cortex was detected by terminal deoxynucleotidyl transferase mediated d-UTP nick end labeling staining (TUNEL). CA1 neuronal loss was counted 24 h after HI by light microscopy.</p><p><b>RESULTS</b>After HI mu-calpain mRNA began to increase at 6 h and reached peak at 24 h compared to the control (1.805 and 4.83 vs. 1, P < 0.05); mu-calpain was activated through autolysis, the ratio of its activated fragment (76 000) vs. whole fragment (80 000) was significantly higher at 6 h (0.547 +/- 0.095) compared to the control (0.095 +/- 0.016, P < 0.05), it reached peak at 24 h (0.921 +/- 0.058, P < 0.01) and was still at a high level at 72 h (0.708 +/- 0.025, P < 0.05). Expression of activated caspase-3 protein reached peak at 24 h (3.78 +/- 0.30, P < 0.01), decreased to the same level as the control (1.56 +/- 0.07) at 72 h (1.82 +/- 0.11, P > 0.05). Apoptotic cells in the cortex ipsilateral to HI insult increased after HIBD, reached peak at 24 h (135.46 +/- 17.52/visual field) and was still markedly higher at 72 h (79.32 +/- 17.79/visual field) compared with the control (5.33 +/- 1.53/visual field, P < 0.01). At 24 h after HI CA1 neuronal loss (30.0 +/- 6.2/oil immersion lens field) in the HIBD group was significantly higher than that of the control (2.4 +/- 0.3/oil immersion lens field, P < 0.01). However, in the MDL group the expressions of mu-calpain and caspase-3 proteins were diminished, TUNEL positive cells at 6 h and 24 h were decreased and CA1 neuronal loss (18.2 +/- 2.4/oil immersion lens field, P < 0.05) was alleviated. The amount of micro-calpain mRNA was decreased in the MDL group, but there was no significant difference compared with the HIBD group.</p><p><b>CONCLUSION</b>mu-calpain gene and protein expressions increased after HI, which may contribute to the pathogenensis of HIBD. Calpain inhibitor-3 may intervene neural necrosis and apoptosis by diminishing expressions of mu-calpain and caspase-3 to play a protective role after HI insult of neonatal brain.</p>

Roles of glutamate receptor 2 and cellular free calcium in the pathogenesis of periventricular leukomalacia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the expression of the AMPA receptor subunit glutamate receptor 2 (GluR2) and the cellular free calcium concentration in the white matter of neonatal rats with periventricular leukomalacia (PVL) and their roles in the pathogenesis of PVL.</p><p><b>METHODS</b>A PVL model was prepared by unilateral carotid artery ligation (UCL) followed by exposure to 6% oxygen for 4 hrs in 2-day-old rats. The neonatal rats performed a sham operation, without hypoxia-ischemia (HI), were used as the control group. At 12, 24, 48 and 72 hrs of HI, the expressions of GluR2 mRNA and protein in the white matter were detected using real time quantitative PCR and Western blot respectively. Spectrophotofluorimetry and Fura 2/AM were used to detect the cellular free calcium concentration.</p><p><b>RESULTS</b>The expressions of GluR2 mRNA and protein in the white matter were significantly reduced in the PVL group at 24 hrs of HI, and remained at lower expressions until 72 hrs of HI compared with the control group (P < 0.05). The cellular free calcium concentrations increased significantly in the PVL group at 12 hrs of HI, and remained at higher levels until 72 hrs of HI compared with the control group (P < 0.05).</p><p><b>CONCLUSIONS</b>The expressions of GluR2 mRNA and protein in the white matter decreased whereas the cellular free calcium concentration increased in neonatal rats with PVL. The decreased expression of GluR2 might lead to the overloading of cellular calcium in the white matter, which may cause neuronal damage and death.</p>

Expression of P75NTR protein and RhoA mRNA in the brain of neonatal rats with white matter damage / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Recent studies have indicated that the signal pathway of NgR-P75NTR- RhoA plays a key role in nerve injury and remodeling, but its exact mechanism and the role of the downstream molecule RhoA regulated by P75NTR remain unclear in hypoxia-ischemia (HI) neonatal animals. The present study was designed to assess the expression of P75NTR protein and RhoA mRNA in neonatal white matter and to investigate their relationship in newborn rats with white matter damage (WMD).</p><p><b>METHODS</b>The rat WMD model was established by the ligation of right common carotid artery, followed by 6% hypoxia exposure for 4 hrs. The control group was sham-operated, without HI treatment. The histological changes of brain tissue were observed under light and electron microscopes. Expression of P75NTR protein and RhoA mRNA in the brain white matter after 12, 24, 48 and 72 hrs and 7 days of HI were detected by RT-PCR and immunohistochemistry, respectively.</p><p><b>RESULTS</b>Periventricular white matter damage was observed by 48 hrs of HI. Expression of P75NTR protein increased in the striatum and callosum zones at 12 hrs, peaked at 48 hrs, and remained at a higher level than control until 72 hrs of HI in the WMD group (P < 0.01). After 7 days of HI expression of P75NTR protein was no longer statistically different from controls. The RhoA mRNA was higher in the WMD group for the first 72 hrs and then declined to control values.</p><p><b>CONCLUSIONS</b>Increased P75NTR protein might mediate apoptosis of nerve cells and inhibit the regeneration of neuron axons. The subsequent decline back to control value may be correlated with the aggregation of necrosis of nerve cells after HI. The patterns of RhoA mRNA expression were consistent with those of P75NTR protein, suggesting that the increased P75NTR level may promote RhoA mRNA expression.</p>

NgR expression in oligodendrocyte precursor cells and its changes after oxygen & glucose deprivation in neonatal rats / 中国当代儿科杂志

<p><b>OBJECTIVE</b>This study examined the NgR expression in oligodendrocyte precursor cells (OLPs) and its changes after oxygen & glucose deprivation (OGD) in order to explore the role of NgR expression in the regeneration of OLPs after OGD in neonatal rats.</p><p><b>METHODS</b>The OLPs from 2-day-old neonatal rats were separated by improved separation and purification through agitation and then cultured in chemically defined medium. OLPs OGD model was prepared using the medium consisting of Na2S2O4 and Earle's fluid in vitro. Immunofluorescence assay was applied to identify the OLPs with its specific antibodies such as A2B5, O4 and O1. Western blot was used to detect the NgR expression in OLPs 10 and 30 minutes after OGD. The livability rate of cells was detected by MTT.</p><p><b>RESULTS</b>NgR expression was found in both the cell body and the prominence of purified OLPs. NgR expression in OLPs increased significantly 10 and 30 minutes after OGD compared with that in OLPs without OGD (controls, P < 0.05). MTT showed that the livability rate of OLPs at 30 minutes following OGD was significantly lower than that of controls (65.97+/-3.69% vs 97.17+/-6.88%, P < 0.05).</p><p><b>CONCLUSIONS</b>NgR is expressed in both the cell body and the prominence of OLPs. NgR expression increases while cell livability decreases following OGD, suggesting that NgR may play a role in the inhibition of regeneration of OLPs.</p>

Expression of F-actin and RhoA in experimental hypoxic-ischemic white matter damage in premature SD rats / 中华儿科杂志

<p><b>OBJECTIVE</b>White matter damage (WMD) in preterm infants is a well-recognized serious complication of prematurity. The collapse of cell skeleton of growth cone after hypoxia-ischemia (HI) is considered as the basic neuropathologic change of the long-term residuals of premature white matter damage. F-actin is the major component of cell skeleton and maintains the normal form of cells, its function and potential mechanism of WMD have not been reported. In this study, changes of F-actin and its influencing factor RhoA were investigated.</p><p><b>METHODS</b>Totally 184 Sprague-Dawley (SD) rats (age 2 days, body weight 6 to 8 grams) were randomly divided into 14 groups: 7 different time WMD groups (HI 12 h, 24 h, 48 h, 72 h, 7 d, 14 d, 28 d) and 7 corresponding control groups. The 2 day-old SD rats were subjected to ligation of right carotid artery (ischemia), and then they were put into a box full with 6% oxygen and 94% nitrogen for 4 hours (hypoxia). The light microscopy was used to observe the brain pathological changes and the electron microscopy was used to detect the brain ultrastructural changes after hypoxia and ischemia. Eighty SD rats were used for flurescent-immunohistochemical method to detect the distribution of F-actin in cell membrane and cytoplasm of both WMD groups and the control groups at 12 h, 24 h, 48 h, 72 h, 7 d after HI respectively. The distribution of F-actin was reflected by the percentage of non-integrity cells. Another 80 SD rats were used for real time RT-PCR to detect the expression of RhoAmRNA in the white matter tissue of both WMD groups (HI 12 h, 24 h, 48 h, 72 h, 7 d) and the control groups.</p><p><b>RESULTS</b>(1) Necrosis of lateral ventricle tissue was observed by 72 h after HI. Dilatation of ventricle and formation of capsular space beneath white matter had been observed by 14 d after HI. (2) Disregulation, pyknosis, mitochondrion swelling and chromatin agglutination were observed in WMD groups. The maldevelopment of myelins in WMD groups was detected at 1 h after HI. (3) The fluorescent stains decreased on cellular membrane, but increased in cytoplasm with time. The percentage of non-integrity cells was significantly higher (P < 0.05) in HI groups (0.32 +/- 0.04, 0.43 +/- 0.04, 0.56 +/- 0.03, 0.65 +/- 0.04, 0.87 +/- 0.03) than the controls (0.02 +/- 0.01, 0.02 +/- 0.01, 0.01 +/- 0.01, 0.02 +/- 0.01, 0.02 +/- 0.01). (4) The expression of RhoA mRNA was significantly increased (P < 0.05) in HI groups (1.205, 2.415, 4.830, 1.500) in the white matter tissue compared with the controls (0.300, 0.375, 0.375, 0.530) at 12 h, 24 h, 48 h, 72 h after HI. The expression of RhoA mRNA reached the peak value at HI 48 h, and then gradually decreased. The expression of RhoA mRNA at HI 7 d in WMD group (0.500) was not significantly different from the control (P > 0.05).</p><p><b>CONCLUSION</b>(1) The pathological and ultrastructural changes of white matter in WMD groups after HI suggest that the WMD model was successfully set up in premature 2 days SD rats. (2) F-actin is redistributed within cells after HI: expression in membrane is decreased and expression in plasma was increased. The redistribution possibly results in the collapse and retraction of cells. (3) The expression of RhoA mRNA is increased significantly after HI, which may lead to the redistribution of F-actin. (4) The increase of the expression of RhoA mRNA is not persistent, but the redistribution of F-actin is continued, which suggests that RhoA may not be the only factor affecting the redistribution of F-actin.</p>

Isolation,Characterization and Identification of SD Rats′ Oligodendrocyte Precursor Lineage Cells in vitro / 实用儿科临床杂志

Objective To obtain highly purified oligodendrocyte precursor lineage cells in vitro and make identification.Methods The oligodendrocyte precursors were separated from astrocyte by orbital shaker and further purified by differential adhesion,and finally cultured in chemically defined serum-free medium,with appended neurotrophin 2(N2),platelet-derived growth factor(PDGF),basic fibroblast growth factor(bFGF).Immunofluorescence assay was applied to identify the separated cells with A2B5,O4,O1 and glial fibrillary acidic protein(GFAP) antibodies.Results Over 95% of cultured oligodendrocyte precursor cells were obtained.The oligodendrocyte progenitors were A2B5 and O4 positive,immature oligodendrocytes were O4 and O1 positive while GFAP were negative.Conclusions Separation and purification by shaking and differential adhesion and chemically defined medium are suitable and effective to obtain highly purified oligodendrocyte precursor cells.Cell output will increase notabily and rest in immature phase by appending both N2,PDGF and bFGF.

Establishment and Evaluation on Experimental Newborn Rats Model of Periventricular Leukomalacia / 实用儿科临床杂志

Objective To establish the 2 day-old SD rats model of periventricular leukomalacia(PVL).Methods Sixty-five healthy 2 day-old SD rats were randomly divided into 3 experimental PVL groups and 3 control groups.The experimental PVL groups were subjected to right carotid ligation(RCL),and then they were suffered from hypoxia by 6% oxygen and 94% nitrogen for 4 hours.Meanwhile sham surgeries were performed on control groups without exposed to hypoxia.Light and electronic microscopy were used to observe brain pathological changes.Immunohistochemistry methods were used to detect the distribution and expression of glial fibrillary acidic protein(GFAP),?-amyloid precursor protein(?-APP),myelin basie protein(MBP) and O4 of brain at 72 hours post-operation.Han-(ging) test,inclined plane test,open field test and cylinder test were performed on the rats 28 days post-operation.Results 1.In the PVL groups,light and electronic microscopy showed that tissue necrosis was observed in the periventricular white matter area at early stage,and at later stage right ventricular dilation,decrease of the corpus callosum area and loss of medullary sheath were detected.The morphometrical analysis showed that GFAP and ?-APP integrated optical density(A) of PVL group was increased,and mean diameter of GFAP-immunoreactive cells was also increased in PVL group,while MBP A of PVL group was decreased compared with contral group.The density of O4-immunoreactive abnormal cells was dramatically increased in PVL group.The outcomes of neurobehavioral tests of PVL group were greatly abnormal compared with control group.Conclusion The changes in 2-day-old SD rats,RCL-hypoxia model are accor-(ded) with the pathology and behavior characeriatis of PVL.

Brain mitochondrial DNA damage of newborn piglets following hypoxia-ischemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>This study investigated the 8003 base pair (bp) fragmentation damage of brain mitochondrial DNA in newborn piglets at different times after hypoxic-ischemic brain damage (HIBD) so as to explore the biomolecular foundation of neonatal neuronal metabolic disorders.</p><p><b>METHODS</b>Fifty 3-day-old piglets were randomly assigned into Control and HIBD groups. The HIBD group was subdivided into groups sacrificed at 0, 24, 48 and 72 hrs post-HIBD (n=10). HIBD was induced by left carotid ligation and exposure to 8% oxygen for 2 hours. The Control group was exposed to air and was sham-operated. The left hippocampal cortexes of all subjects were obtained to amplify the fragments of 200 bp and 8003 bp by the LX-PCR method. The PCR products were electrophoresed on agaros gels to obtain the integral optical density (IOD).</p><p><b>RESULTS</b>The IOD of 8003 bp fragment was markedly reduced in the HIBD 0 hr group (22.616 +/- 2.276) when compared with that of the Control group (56.995 +/- 0.317) (P < 0.05). The IOD value remained lower at 24 hrs (27.719 +/- 0.309) and 48 hrs post-HIBD (49.491 +/- 3.233) (P < 0.05). Until 72 hrs post-HIBD, the IOD (55.972 +/- 2.236) restored to the control value.</p><p><b>CONCLUSIONS</b>The brain mitochondrial DNA was fragmented in newborn piglets following brain hypoxia-ischemia. It did not recover to normal until 72 hrs post-HIBD. The fragmentation damage of mitochondrial DNA may be related to the depression of mitochondrial respiratory enzymes activity and neuron apoptosis.</p>