Respiratory support in children

Respiratory failure is defined by the inability of the respiratory system to adequately deliver oxygen or remove carbon dioxide from the pulmonary circulation resulting in hypoxemia, hypercapnia or both. A wide variety of disease processes can lead to respiratory failure in children. Multiple interventions can support the paediatric patient with respiratory failure, from simple oxygen delivery devices to high frequency oscillatory ventilation and extracorporeal membrane oxygenation. This article will review available devices to improve oxygenation and ventilation, their advantages and disadvantages, and help guide physicians in the management of children with respiratory failure.     

Facilitating fructose-driven metabolism exerts a protective effect on anoxic stress in Drosophila

Hypoxic stress is linked to various cardiovascular disorders (e.g., stroke, myocardial infarction), mediated, at least in part, by a reduction in ATP synthesis. Fructose-driven glycolysis is proposed as an alternative pathway capable of sustaining ATP production even under anoxic conditions. Here, we tested the hypothesis that facilitating fructose-driven metabolism exerts a protective effect against anoxic stress in Drosophila. Genetically modified flies with the human fructose transporter (GluT5) and ketohexokinase (KHK) genes downstream of upstream activating sequence (UAS) were constructed. The GAL4-UAS system was confirmed to: (i) increase the expression of GluT5 and KHK in a tissue-specific and a time-dependent manner (i.e., whole flies [with Act5c-gene switch GAL4 driver], neurons [with elav-gene switch GAL4 driver]) and (ii) reduce mortality of flies when placed under anoxic stress. Taken together, these data suggest that increasing fructose metabolism may be a clinically relevant approach to minimize hypoxia-induced cellular damage.     

彩色多普勒超声观察胎儿宫内缺氧时氧疗对胎儿-胎盘血流动力学的影响

目的：本文介绍应用彩色多普勒超声技术观察129例胎儿宫内缺氧孕妇氧疗前后的脐动脉及大脑中动脉的血流动力学变化，评价氧疗的临床价值。材料与方法：比较35例宫内生长迟缓（IUGR）胎儿、32例妊高症（PIH）患者胎儿及62例脐带绕颈（UCAN）胎儿氧疗前后的脐动脉及大脑中动脉血流多普勒参数．以脐动脉及大脑中动脉血流阻力指数（RI）为分析指标。结果：IUGR组、重度PIH组氧疗前后胎儿脐动脉血流阻力指数（RIUA）及大脑中动脉血流阻力指数（RIMCA）变化有显著性差异（P〈0．01）；轻中度PIH组氧疗前后胎儿RIMCA及RILCA变化无显著性差异（P〉0．05）；UCAN组氧疗前后胎儿仅RIMCA变化有显著性差异（P〈0．05）。结论：以上数据表明氧疗可明显影响脐动脉及大脑中动脉血流动力学变化，改善胎儿血液循环和供氧。彩色多普勒超声为宫内缺氧胎儿氧疗疗效观察提供了重要依据。     

妊娠期绵羊不同程度高原缺氧模型的建立

目的 应用西北人工实验舱建立妊娠期绵羊不同程度高原缺氧模型,并评估其氧合状态及氧化损伤程度.方法 采用24只人工授精配种成功的妊娠期绵羊,随机均分为平原对照组(LAC)、轻度低氧暴露组(MHE)和重度低氧暴露组(SHE).用人工实验舱模拟西北地区高原低氧低压低温环境,通过调节温度、湿度、压力和空气氧含量等参数制备MHE与SHE动物模型,分别于建模前(0d)与建模后7、15、30、90、120d检测3组动物氧合状态、生命体征及行为模式,动态检测肝脏组织氧化损伤标志物的水平.结果 经不同条件人工实验舱造模30d(MHE组)及90d(SHE组)后,妊娠期绵羊动脉血气指标分别达到轻度和重度缺氧诊断标准.建模后90d,与LAC组比较,MHE组及SHE组妊娠期绵羊呼吸频率减低(P＜0.05),心率升高(P＜0.05),运动减少,且SHE组饮食较MHE组减少;建模后120d,MHE组及SHE组妊娠期绵羊蛋白质氧化损伤的生物标志物羰基(CO)和细胞氧化损伤的生物标志物丙二醛(MDA)水平均明显高于LAC组(P＜0.05),且SHE组明显高于MHE组(P＜0.05).结论 应用西北人工实验舱成功建立了妊娠期绵羊不同程度高原缺氧模型.高原低氧环境可引起妊娠期绵羊氧化应激损伤.     

肿瘤抑制因子PTEN亚细胞定位与缺血-缺氧性脑损伤

第10号染色体缺失的磷酸酶和张力蛋白同源等位基因(PTEN)具有脂质和蛋白双重磷酸酶活性。脑组织缺血-缺氧后PTEN发生活化并向线粒体或胞核内转移,而这种在神经元内的不同亚细胞定位可能最终决定细胞命运。因此,阐明PTEN在脑缺血-缺氧后的亚细胞定位机制,将为各种急慢性神经退行性变疾病的靶向治疗和药物研发提供新思路。     

Ion Transport and Energy Metabolism in Brain

Abstract

The kinetics of extracellular K⁺ activity was compared to the availability of energy in the cortex of rats and gerbils exposed to anoxia, hypoxia, spreading depression, and ischemia.

A combined K⁺/DC surface electrode was used alone or together with a fiber optic light guide in various experiments. All experiments were done on slightly anesthetized animals that were practically awake. The results can be summarized in the following conclusions: (1) Under conditions such as hypoxia or ischemia, K⁺₀ showed a two-phase efflux kinetics, and a transition or critical point was reached where the response proceeds at a higher rate. This critical point was in the range of 10-16 mEq/1 potassium. (2) Availability of oxygen is necessary but not sufficient for a full rate of recovery from a long-term oxygen-deprivation insult. (3) There is an energy debt or energy-transduction bottleneck fonned during a prolonged O₂ insufficiency. This debt is reversed slowly during the recovery phase even when full restitution of O₂ supply and blood flow has occurred.     

Evaluation of spinal evoked potentials: a model for assessment of spinal cord function in isolation

Spinal evoked potentials were recorded from the dorsal columns of in vitro mouse hemicord preparations. The response of these potentials to different periods of hypoxia was studied. A decrease in amplitude of the potential to 50% and 10% of pre-hypoxia reference occurred after 3.19 ± 1.36 and 7.3 ± 2.97 min, respectively. Complete recovery of the potential was seen in specimens exposed to 5 and 10 min of hypoxia. Incomplete recovery occurred with exposure to longer periods of hypoxia. In preparations that remained isoelectric for less than 5 min total recovery was seen.     

RANKL/OPG在高原低氧条件下兔牙周炎发病机制中的作用

目的 研究模拟高原低氧条件下兔牙周炎的病理改变以及与破骨细胞相关的核因子κB受体活化子配体( receptor activator of nuclear factor-κB ligand,RANKL)、骨保护素(osteoprotegenn,OPG)的相关性.方法 40只家兔完全随机分成4组:平原实验组、平原对照组、高原实验组、高原对照组,每组各10只.通过钢丝结扎切牙方法建立家兔牙周炎模型,动物于分组饲养8周后处死,制作牙周组织石蜡切片,HE染色观察牙周组织病理变化、破骨细胞的表达,荧光免疫组化检测牙周组织中RANKL、OPG的表达.免疫荧光组化采用激光扫描共聚焦显微镜对实验组与对照组RANKL、OPG进行半定量分析,并比较其差异.结果 高原实验组与平原实验组、高原对照组和平原对照组RANKL灰度值分别为(1.799±0.036)、(1.519±0.061)、(1.242 ±0.078)、(0.963±0.098),差异有统计学意义(P＜0.05),与高原对照组比较,高原实验组OPG表达降低无统计学意义.高原实验组RANKL与牙周指数呈正相关(P＜0.01).结论 高原低氧条件下可能通过改变破骨细胞的RANKL/OPG调节途径促进牙周炎的发生、发展.     

新生儿缺氧缺血性脑病与急性胆红素脑病的MRI诊断及鉴别

[目的]探讨常规磁共振成像 (MRI )和扩散加权成像 (DWI )鉴别新生儿缺氧缺血性脑病(HIE)与急性胆红素脑病的价值.[方法]回顾性分析伴有基底节累及的HIE新生儿28例和急性胆红素脑病新生儿患者30例的常规MRI及DWI特点.[结果]在T1WI上,HIE患儿苍白球和底丘脑高信号的出现率分别为35.7%(10/...