Spontaneous DNA synthesis of blood lymphoid cells in premature newborn infants,in older premature infants and in full-term newborn infants

In adults, blood cells which synthesize DNA spontaneously are large, pale lymphoid phagocytes. In fetal blood, transitional cells label spontaneously in addition to the lymphoid phagocytes (Prindull et al., 1975a, b). In the present study, we have measured quantitatively by scintillation counting, spontaneous thymidine incorporation of blood cells from different groups of infants.When compared with the conditions in the normal adult, spontaneous DNA synthesis of peripheral blood lymphoid cells is increased by a factor of 16.4 in premature newborn infants (P<0.002), by a factor of 8.7 in full-term newborn infants (P<0.01), and in older premature infants studied at the time of their calculated birth dates by a factor of 4.3 (P<0.001).Spontaneously labelling blood cells most likely are, at least in part, hematopoietic stem cells from the bone marrow.With technical assistance of Brigitte Prindull.     

Effect of lipid emulsion on IL-2 production by mononuclear cells of newborn infants and adults

The in vitro effect of a lipid emulsion (intralipid) on interleukin-2 (IL-2) production by cord blood mononuclear cells (CBMC) of preterm and term newborn infants was examined and compared to that of peripheral blood mononuclear cells (PBMC) of adults. Intralipid, added at concentrations accepted in clinical practice, caused a dose-dependent inhibition of IL-2 activity tested by bioassay. IL-2 levels, tested by radioimmunoassay (RIA), were found to be reduced only in supernatants derived from CBMC of term infants and not in those derived from MC of preterm infants or adults. The capacity of the IL-2 dependent cell line CTLL-2 to respond to IL-2 was abolished in the presence of intralipid, suggesting an interference with the binding of IL-2 to its receptor on these cells. It is conceivable that administration of intralipid to preterm infants may interfere with the binding of IL-2 to the specific receptors on their activated lymphocytes, with a possible subsequent suppression of their immune response.     

围生期窒息新生儿血气分析与神经系统损害

【摘要】目的探讨围生期窒息新生儿PaCO2及pH快速变化及其与神经系统损害之间的关系。方法将55例新生儿分为3组：组1pH〉7．00，无神经系统异常，无需呼吸支持；组2pH≤7．00，余同组1；组3，pH〈7．00，神经系统异常，需辅助呼吸支持。采集脐动脉血、产后1h和2h桡动脉血进行血气分析并观察Apgar评分和临床经过。结果脐动脉血pH值和PaC02各组间有显著差异；产后1h动脉血pH组1、3间和组2、3间有显著差异；产后1h动脉血pH、PaC02分别和脐动脉血pH、PaCO2比较，有显著差异；3组间有不同的神经系统表现；Apgar评分组3较低。结论在严重酸中毒时，胎儿出生后pH、PaC02会发生显著改变，需持续辅助机械通气的患儿有不同的神经系统后遗症。     

围生期窒息新生儿血气分析与神经系统损害

目的探讨围生期窒息新生儿PaCO2及pH快速变化及其与神经系统损害之间的关系。方法将55例新生儿分为3组:组1 pH>7.00,无神经系统异常,无需呼吸支持;组2 pH≤7.00,余同组1;组3,pH≤7.00,神经系统异常,需辅助呼吸支持。采集脐动脉血、产后1 h和2 h桡动脉血进行血气分析并观察Apgar评分和临床经过。结果脐动脉血pH值和PaCO2各组间有显著差异;产后1h动脉血pH组1、3间和组2、3间有显著差异;产后1 h动脉血pH、PaCO2分别和脐动脉血pH、PaCO2比较,有显著差异;3组间有不同的神经系统表现;Apgar评分组3较低。结论在严重酸中毒时,胎儿出生后pH、PaCO2会发生显著改变,需持续辅助机械通气的患儿有不同的神经系统后遗症。     

The effect of phenobarbital on cerebral blood flow in newborn infants with foetal distress

The effect of phenobarbital on cerebral blood flow (CBF) was investigated by the intravenous Xenon¹³³ clearance technique in seven term newborn infants with signs of mild to moderate hypoxic ischaemic encephalopathy, all on sustained spontaneous ventilation. Phenobarbital treatment had no significant effect on CBF 60 min after loading dosage (20mg/kg i.v.). Likewise, no significant change in mean arterial blood pressure, heart rate or transcutaneous gas tensions was observed. Though slight changes in CBF of short duration cannot be excluded, conventional dosage of phenobarbital to term newborn infants with foetal distress apparently imposes no risk of cerebrovascular damage.     

Peripheral circulation in the newborn: Interaction of peripheral blood flow,blood pressure,blood volume,and blood viscosity

Peripheral blood flow and systolic blood pressure (strain-gauge plethysmograph), blood volume (Evans blue) and whole blood viscosity (cone-plate viscometer) have been measured in 66 premature and full-term infants 6 to 144h of age. Blood flow and blood volume were moderately decreased in the infants with respiratory distress. Highly significant (P<0.001) correlations were found betwen blood flow and blood volume (r=0.77), blood pressure and blood volume (r=0.50), peripheral resistance and blood volume (r=-0.44), blood flow and blood pressure (r=0.50), blood flow and peripheral resistance (r=-0.67), peripheral resistance and blood viscosity (r=0.45), and blood viscosity and haematocrit (r=0.86). There was no correlation between peripheral blood flow and blood viscosity. However, at given blood volume, peripheral blood flow decreased with increasing blood viscosity. These results indicate that in newborn infants peripheral blood flow, blood pressure and peripheral resistance are influenced by blood volume, but also depend on blood viscosity.Supported by Deutsche Forschungsgemeinschaft (SFB 147)     

Effects of dopamine infusion on plasma catecholamines in preterm and term newborn infants

Newborn infants (21 preterm and 13 term) received dopamine infusions at a low (2.5–3.4 g/kg per min) and/or high (5–10 g/kg per min) infusion rate and changes in plasma catecholamines were monitored. The mean baseline values for dopamine, noradrenaline and adrenaline were between 240 and 560, 125 and 144 and 62 and 82 pg/ml, respectively. During low-rate infusion of dopamine, there was a significant increase in plasma dopamine (20–100fold), noradrenaline (three- to five-fold) and adrenaline (threefold). Administration of dopamine at the high rate resulted in an even larger increase in the plasma catecholamines (dopamine, 100–300fold; noradrenaline, seven- to eightfold; adrenaline, four- to sixfold). In a double-log plot, there was a highly significant correlation between the plasma concentrations of dopamine and noradrenaline (r=0.77;P<0.001). In conclusion, infusion of dopamine in term and preterm newborn infants is accompanied by an enhanced sympatho-adrenal tone which may contribute to the cardiovascular effects of dopamine in these patients.     

Incidence and duration of total occlusion of the radial artery in newborn infants after catheter removal

The incidence and duration of total occlusion of the radial artery after catheter removal was determined using repeated Doppler flow measurements. Thirty-two newborn infants with birthweights ranging from 945 g to 3890 g (median 1935 g) and gestational age ranging from 26 to 40 weeks (median 32 weeks) were studied. In 20 out of 32 infants (63%), complete occlusion of the radial artery occurred. The number of occlusions were not related to birthweight, gestational age or duration of cannulation. In all infants, blood flow in the radial artery resumed within 1–29 days after catheter removal. The duration of occlusion was directly related to the duration of cannulation and inversely related to birthweight.This study demonstrates a high frequency of total occlusion of the radial artery in newborn infants after percutaneous radial artery cannulation. In the majority of infants with a radial artert catheter, blood flow to the tissue distal to the cannulation site is dependent solely on the existence of an adequate arterial palmar collateral circulation.     

致敏大鼠气道细胞DNA合成增加与气道重塑关系的实验研究

目的　观察重复过敏原吸入刺激致敏的大鼠气道细胞DNA合成和气道壁结构的改变 ,并探讨气道重塑反应发生的机制。方法　应用SD大鼠建立哮喘模型 ,采用胶原染色、粘液染色和双标免疫组化染色等技术对气道细胞的DNA合成和气道重塑进行研究。结果　 (1)模型组和正常组相比 ,气道上皮下胶原组织大量沉积 ,上皮表面粘液层增厚 ,杯状细胞增生 ,并有大量炎性细胞浸润 ;(2 )模型组气道平滑肌细胞DNA合成表达Brdu阳性核计数为 10 3± 2 1,明显高于正常对照组 (7 2±2 1) ,(t=3 6 6 ,P <0 0 1) ;模型组气道上皮细胞的DNA合成表达Brdu阳性核计数为 2 1± 7,亦明显高于正常对照组 (16± 4 ) (t=2 35 ,P <0 0 5 )。结论　 (1)重复过敏原刺激可使气道细胞DNA合成增加 ,上皮下胶原沉积和粘液分泌增加。 (2 )变态反应性炎症所致的微环境改变可能是导致气道重塑反应发生的主要机制     

Glucose disappearance in infants of diabetic mothers. III. Relationship of spontaneous glucose disappearance to glucose tolerance,neonatal hypoglycemia and lowest blood glucose

Spontaneous glucose disappearance in the first 90 min of life and glucose disappearance following an intravenous injection of 1 g/kg dextrose were measured in 23 infants of insulin-dependent diabetic mothers. Spontaneous disappearance was log-linear in 12/23 infants, providing for calculation of an endogenous K_t which correlated significantly (P < 0.01) with the exogenous Kt determined after the dextrose injection, r = 0.74.Hypoglycemia <20 mg/dl occurred in 4/23 infants, and was identified during the spontaneous glucose disappearance (3 infants) and/or predicted by an endogenous K_t > 3.0%/min (2 infants). There was also a significant inverse correlation (P < 0.01) of the lowest blood glucose obtained within the first 24 h of life with the endogenous K_t, r = 0.61. There was no correlation of the endogenous or exogenous Kt, lowest blood glucose or hypoglycemia with White's classification of the maternal diabetes, diabetic control during pregnancy, the maternal blood glucose at delivery or the cord blood glucose.These data indicate that determination of spontaneous glucose disappearance within the first 90 min of life is useful in identifying infants of diabetic mothers with hypoglycemia or those who will subsequently develop hypoglycemia.     

短发夹RNA沉默Tim3分子表达对哮喘小鼠外周血Th1和Th17细胞的影响

目的：建立小鼠支气管哮喘模型,采用T 细胞免疫球蛋白黏蛋白分子-3（Tim-3）特异短发夹RNA（shRNA）沉默外周血单个核细胞（PBMCs）中Tim-3的表达,探讨Tim-3对辅助性T细胞1 (Th1)和Th17细胞分化的影响。方法：用卵白蛋白(OVA)致敏并激发建立哮喘小鼠模型,分离哮喘小鼠PBMCs,用 Tim-3特异的shRNA 片段沉默哮喘小鼠PBMCs中高表达的Tim-3 基因。Real-time PCR 和 Western blot 检测 Tim-3 的表达,流式细胞分析技术（FACS）检测Th1和Th17的比例;ELISA 检测细胞培养上清液中干扰素 γ（IFN-γ）,白介素-4（IL-4）,和 白介素-17（IL-17）的水平。结果：哮喘组小鼠PBMCs中Tim-3 mRNA表达明显升高; 使用特异Tim-3 shRNA沉默哮喘小鼠PBMCs后,沉默组PBMCs中Th1细胞比例显著升高,Th17细胞比例显著下降,与阴性对照组相比差异有统计学意义（P<0.01）;沉默组PBMCs培养上清液中IFN-γ明显升高,IL-17明显降低,与阴性对照组相比差异有统计学意义（P<0.05）, IL- 4水平无明显变化。结论：特异Tim-3 shRNA有效地沉默了Tim-3的表达,Tim-3表达的改变影响了T 细胞的分化。     

Differences in adhesion receptor expression between immature and older platelets and red blood cells of neonates and adults

PURPOSE: To examine the hypothesis that reticulated platelets and reticulocytes show elevated adhesion receptor expression compared with mature cells in both adult and neonatal cells. METHODS: Flow cytometry was used to examine laminin, fibronectin (VLA-6), and thrombospondin (glycoprotein IV [GPIV]) expression in reticulated red cells, reticulated platelets, and older peripherally circulating mature red cells and mature platelets in seven newborn cord blood samples and blood samples from eight adult volunteers. RESULTS: The difference in the neonatal reticulated platelet percentage of 9.2+/-14.8% was not statistically significant from the adult reticulated platelet percentage of 5.0+/-1.5% in this small population. There was a statistically significant difference between the reticulated cord blood red cell mean of 7.7+/-1.8% and the adult mean of 3.1+/-0.43%. Mean expression of VLA-6 was 96% in adult reticulated platelets, 79% in adult mature platelets, 81% in cord reticulated platelets and 65% in cord mature platelets. Mean expression of GPIV was similar, with corresponding values of 90%, 71%, 78%, and 57%. Reticulated red cells in adults averaged 44% VLA-4 and 46% GPIV; cord reticulocytes were 9% and 15%, respectively. CONCLUSIONS: Reticulated cells newly released from the bone marrow express more adhesive receptors than mature cells in both groups. Cord blood samples showed hypoexpression of both receptor types in red blood cells and platelets.