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There is a large number (1.5 million per year) of premature births in China. It is necessary to obtain the authentic incidences of intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL), the common brain injuries, in Chinese premature infants. The present multicenter study aimed to investigate the incidence of brain injuries in premature infants in ten urban hospitals in China.The research proposal was designed by the Subspecialty Group of Neonatology of Pediatric Society of the Chinese Medical Association. Ten large-scale urban hospitals voluntarily joined the multicenter investigation. All premature infants with a gestational age ≤ 34 weeks in the ten hospitals were subjected to routine cranial ultrasound within three days after birth, and then to repeated ultrasound every 3-7 days till their discharge from the hospital from January 2005 to August 2006. A uniform data collection sheet was designed to record cases of brain injuries.The incidences of overall IVH and severe IVH were 19.7% (305/1551) and 4.6% (72/1551), respectively with 18.4% (56/305) for grade 1, 58.0% (177/305) for grade 2, 17.7% (54/305) for grade 3 and 5.9% (18/305) for grade 4 in nine hospitals. The incidences of overall PVL and cystic PVL were 5.0% (89/1792) and 0.8% (14/1792) respectively, with 84.3% (75/89) for grade 1, 13.5% (12/89) for grade 2, and 2.2% (2/89) for grade 3 in the ten hospitals. The statistically significant risk factors that might aggravate the severity of IVH were vaginal delivery (OR=1.883, 95% CI: 1.099-3.228, P=0.020) and mechanical ventilation (OR=4.150, 95% CI: 2.384-7.223, P=0.000). The risk factors that might result in the development of cystic PVL was vaginal delivery (OR=21.094, 95% CI: 2.650-167.895, P=0.000).The investigative report can basically reflect the incidence of brain injuries in premature infants in major big cities of China. Since more than 60% of the Chinese population live in the rural areas of China, it is expected to undertake a further multicenter investigation covering the rural areas in the future.

To compare the newborn piglet models of hypoxic ischemic brain damage in hypoxia and hypoxia combined with occlusion of both carotid arteries.Twenty four 7-day-old piglets were divided into two groups. Group H: mechanical ventilation with low concentration of oxygen, Group HI: mechanical ventilation with low concentration of oxygen combined with occlusion of both carotid arteries. The piglets were inhaled with 10%, 8%, and 6% low-concentration oxygen for 30 min, and grouped into mild, moderate, and severe hypoxia ones. The changes of physiological parameter, cerebral blood flow and cerebral oxygen perfusion were detected.There were no significant differences in blood gas analysis of oxygen saturation, blood lactic acid and pH between the two groups(P0.05).The mean arterial pressure of severe hypoxia in HI was significantly lower than in H (P0.05). The cerebral blood flow in H and HI was relatively stable after different degrees of hypoxia. As compared with the cerebral blood flow perfusion in group H and HI, there were no significant differences between them(P0.05). The cerebral oxygen perfusion in H and HI was significantly descent after different degrees of hypoxia(P0.05). As compared with the cerebral oxygen perfusion in groups H and HI, there were no significant differences between them.H and HI have the same effect on physiological parameter, cerebral volume and cerebral oxygen perfusion of newborn piglets. The mechanical ventilation with low concentration of oxygen to newborn piglets can develop the HIBD model, it is not necessary to occlude carotid arteries.

To understand the value of measuring neonatal cerebral regional oxygen saturation (rSO2) using near infrared spectroscopy (NIRS) in assessing cerebral oxygenation, to establish the normal range of neonatal cerebral rSO2 and to collect data of the changes of cerebral rSO2 under certain disease status.Nine large hospitals participated in the multicenter randomized clinical trial from Jan 2007 to Apr 2008. Using the NIRS human tissue oximeter (TSAH-100) independently developed in China, the cerebral rSO2 of 223 normal full-term and 95 otherwise healthy preterm neonates without any special disease, was detected at 1, 2 and 3 days after birth, respectively. The cerebral rSO2 of 102 neonates with diseases which may affect the cerebral oxygenation, was also detected during the severe phases. The pulse oxygen saturation (SpO2) measured at the finger tip, and also the arterial oxygen saturation (SaO2) measured by blood gas analysis, which could indicate the oxygen supply of the whole body, were obtained simultaneously. The correlations among cerebral rSO2, pulse SpO2 and arterial SaO2 were analyzed.(1) The cerebral rSO2 of the normal full-term neonates was (62+/-2)%. Cerebral hypoxia was defined as rSO2 lower than 58%. The cerebral rSO2 of the normal full-terms was steady at 1, 2 and 3 days after birth respectively, without any significant differences among them (F=0.610, P0.05). The cerebral rSO2 of the neonates with diseases was (55+/-7)%, which was significantly lower than that of the normal full-term neonates (t=15.492, P0.05). (2) The cerebral rSO2 was positively correlated with the SpO2 (r=0.74, P0.01) and the SaO2 (r=0.71, P0.01). (3) Under some special diseases, the changes of cerebral rSO2 was asynchronous with those of the SpO2: (1) For 18 cases under severe cerebral damages or under relatively low hemoglobin concentration, the cerebral rSO2 was significantly low (50%-58%), but the SpO2 was still normal (above 90%). (2) During the recovery of some critically ill neonates, the increase of cerebral rSO2 was lagged as compared with that of pulse SpO2. Especially, during the severe phases of 6 cases with multi-organ failure, the SpO2 and the cerebral rSO2 were both significantly low (55%-80% for SpO2, and 44%-50% for cerebral rSO2); when the diseases were alleviated, although the SpO2 recovered to above 85%, the cerebral rSO2 was still significantly low (around 50%). (3) In 3 cases, during the severe phases of serious hypoxic-ischemic encephalopathy (HIE), the cerebral rSO2 significantly increased to 70%-72%, which was significantly higher than the normal value (62%).The range of cerebral rSO2 of the normal full-term neonates was (62+/-2)%. Cerebral oxygenation can be externally indicated by the rSO2 noninvasively and continuously measured by NIRS, which was positively correlated with traditional pulse SpO2 and arterial SaO2. In some special diseases, the rSO2 measured by NIRS can be helpful for clinical diagnoses and treatments.

To study the effect of hyperbaric oxygenation (HBO) on the differentiation of the implanted human neural stem cells (hNSCs) into neurons in neonatal rats following hypoxic-ischemic brain damage (HIBD).HIBD model was prepared by ligation of the left common carotid artery, followed by 8% hypoxia exposure in 7-day-old Sprague-Dawley rat pups. Three days later, the rats received implantation of hNSCs into the left cerebral ventricles. Then the survived rats were randomly divided into two groups: transplantation alone and transplantation+HBO (n=8 each). HBO treatment was administered (1.8 ATA, 1 hr once daily for 10 days) in the transplantation+HBO group 1 hr after hNSCs transplantation. Brains were removed 10 days after transplantation. Frozen coronal sections were prepared for immunofluorescence analysis to detect the neural differentiation of the transplanted cells in the cerebral cortex and hippocampus.Differentiated neurons of implanted cells distributed mainly in the cortex and the hippocampus of the injured side. There was no difference in the number of neurons in the cortex between the two groups, while the number of neurons in the hippocampus significantly increased in the transplantation+HBO group compared with that in the transplantation alone group (231.4+15.1 vs 162.6+5.6; P0.05).HBO treatment may promote the differentiation of implanted hNSCs into neurons in the hippocampus of neonatal rats following HIBD.

To study correlation of brain hypoxia of different degrees with brain function and damage.The brain regional oxygen saturation (rSO2) was determined by using a non-invasive near infrared spectroscopy (NIRS) technique in 15 piglets; the piglets were subjected to inhale 3% - 11% oxygen-nitrogen mixed gas through mechanical ventilation for 30 min. The piglets were divided into groups according to the level of brain rSO2 (i.e.30%, 30% - 35%, 35% - 40%, and 40% - 50%), and the data were compared with those of the control group (rSO260%). Changes of brain function were detected through amplitude and frequency of EEG waves and signal complexity. The piglets were sacrificed via decapitation 72 h after brain damage, and then histopathological and ultrastructural examinations were performed on cerebral cortex and hippocampal CA1 area.In the group with rSO240%, the mean arterial pressure (MAP) after hypoxia was (56 +/- 0.00) mm Hg (1 mm Hg = 0.133 kPa), the blood lactic acid (LA) was (2.3 +/- 1.2) mmol/L, the EEG findings were within normal range, and there was no change in brain tissue ultrastructure. In the group with brain rSO2 = 30% approximately 40%, the MAP was (73 +/- 8) mm Hg, the LA was (8.2 +/- 3.9) mmol/L, the EEG waves showed decreased amplitude, frequency and complexity, but restored to some extent after hypoxia. The brain tissue ultrastructure showed damages to the cerebral cortex and neuron mitochondria at hippocampal CA1 area. In the group with brain rSO230%, the MAP was (35 +/- 0) mm Hg, the LA was (12 +/- 2) mmol/L, the EEG showed decreased amplitude, frequency, and complexity of signals compared with those of the normal control group, and was difficult to restore after hypoxia in some of the piglets; the brain tissue ultrastructure appeared to be similar to the changes seen with high-degree swollen cerebral cortex and neuron mitochondria at hippocampal CA1 area.Different degrees of hypoxia had different influence on brain function and brain damage. The lower the brain rSO2, the more severe the damages to the brain and its function. The rSO2 of brain tissues detected with noninvasive NIRS can reflect brain injury and its severity during cerebral anoxia.

To investigate the clinical manifestations, imaging characteristics as well as prognosis of neonatal polycythemia complicated with brain damage.One hundred and sixteen in-patients with neonatal polycythemia admitted to our hospital during January 2003 to October 2005 were analyzed. Their clinical manifestations were observed. Craniocerebral ultrasonic examination (2D, 3D), CT and MRI were employed to dynamically observe the craniocerebral imaging variances as well as the cerebral hemodynamic variations and near infrared spectroscopy (NIR) was adopted to test the cerebral oxygenation. Twenty-two cases with moderate or severe disease were followed up for 3 to 12 months.Out of the 116 polycythemic neonates, 53 cases had brain damages, of whom 31 had mild, 14 had moderate, and 8 had severe damages. Cranial imaging alterations were mostly ischemic injuries of various areas of different severity. The severity of brain damage was closely related to the duration of polycythemia, oxygen saturation of cerebral tissues as well as cerebral hemodynamic abnormalities. Brain injury was likely to occur in those whose polycythemia persisted for more than three days. The regional saturation of oxygen (rSO(2)) in mild brain injury cases was found to be 52.1%, while it was 47.1% in moderate and severe brain injury cases. Compared to the 58% as found in non-brain injury cases, the variance was found to be statistically significant (F = 104.466, P0.01). Among the cases with brain injury, cerebral hemodynamics displayed a slowdown in the blood flow velocity in the cerebral anterior artery and medium artery during the systolic phase and/or the diastolic phase. The abnormality ratio was closely related to the severity of brain injury. Through the chi(2) test the variance was proved to be statistically highly significant (chi(2) = 18.889, P0.01), however it was not correlated with the increase of the initial levels of hemoglobin (Hb) and hematocrit (HCT) (P0.05). During the follow up, neurological developmental abnormalities of various severity were found to exist in the cases with moderate (5/12) and severe disease (7/8), while cerebral palsy or epilepsy was not yet found.Neonatal polycythemia might tend to bring about a reduction in the perfusion of cerebral blood flow and damaged cerebral oxygenation metabolism which in turn might lead to cerebral ischemic injury, which in some of the moderate and severe cases might lead to long-term neurological complications. Imaging investigations especially craniocerebral ultrasonic examination could be the practical means for the early diagnosis and evaluation of prognosis.

To study the relationship between early brain response to extrinsic stimulation and neurodevelopment in preterm infants, assess the brain function of preterm infants in the early stage, and thereby to provide objective evidence for the degree of neurodevelopment in preterm infants and to evaluate prognosis.Using near infrared spectroscopy (NIRS), the brain response to sound stimulation of 90 preterm infants at different gestational age was observed and compared with the result obtained from 20 full term infants. The neonatal behavioral neurological assessment (NBNA) was performed at corrected age of 40 weeks, and the infants were followed up for 2 years. The effect of gestational age and brain damage on preterm infants, the relation between early brain response in preterm infants and their neurodevelopment was evaluated.All the preterm infants responded to different degrees to auditory stimulation after birth. The time to beginning to react and the time to appearance of the peak reaction were attained after auditory stimulation and the time to beginning to resume when the auditory stimulation was stopped was (278 +/- 94) s, (446 +/- 67) s and (199 +/- 52) s, respectively, which were significantly longer than those observed in the full term infants (107 +/- 30) s, (264 +/- 51) s and (131 +/- 46) s, respectively. The maximum reactions of hemoglobin, oxyhemoglobin and regional oxygen saturation in the infants after gestational age 32 weeks was (0.3 +/- 0.3)%, (0.7 +/- 0.5)% and (0.3 +/- 0.3)%, respectively, which were significantly lower than those in the full term infants (1.7 +/- 0.7)%, (1.7 +/- 0.8)% and (1.6 +/- 0.7)%, respectively. When the brain response of preterm infants was compared with that in infants without brain damage, the speed of the reaction was slow, the maximum reaction was low. The brain response in preterm infant was correlated with NBNA at corrected age of 40 weeks. It was found during the following-up that abnormal neurodevelopment was associated with poor brain reaction.NIRS can be used to evaluate brain response of infants. Preterm infants display brain response to auditory stimulation. Early brain response is correlated with neurodevelopment.