新生大鼠缺氧缺血性脑病模型中己酮可可碱的干预作用研究

目的观察不同时间给予己酮可可碱（pentoxifylline，PTX）对新生大鼠缺氧缺血性脑损伤（hypoxic-ischemic brain damage，HIBD）模型的影响。方法建立新生大鼠HIBD模型，120只出生7d的Wistar大鼠随机分为假手术（Sham）组、HIBD模型组和3种PTX（50mg／kg腹腔注射）给药组，即缺血末均给药（I＋PTX）组、缺氧末给药（H4-PTX）组及缺血和缺氧末均给药（I，H＋PTX）组，各组均于缺血缺氧处理后72h取出左脑，测定脑组织水含量、大脑皮层神经组织游离钙离子浓度、超氧化物歧化酶（SOD）、丙二醛（MDA）、一氧化氮合酶（NOS）及一氧化氮（NO）。结果HIBD模型组与Sham组相比，脑组织含水量、游离钙离子浓度、MDA、NOS及NO水平显著升高（均P〈0．01），SOD水平明显降低（P〈0．01）。3种PTX给药组与HIBD模型组相比，脑组织含水量、游离钙离子浓度、MDA、NOS及NO水平均显著降低（均P〈0．01），SOD水平明显升高（P〈0．01）。以上作用尤以（I，H＋PTX）组明显。结论PTX对新生大鼠缺氧缺血后脑组织有保护作用，其机制可能与PTX改善能量代谢及减少局部细胞毒性物质有关。     

促红细胞生成素对缺氧缺血新生鼠脑匀浆一氧化氮及血浆内皮素的影响

目的探讨体外注射重组人促红细胞生成素(rhEPO)对新生鼠缺氧缺血后脑组织一氧化氮(NO)和NO合成酶(NOS)及血浆内皮素(ET)水平的影响,阐明其对缺氧缺血(HI)新生动物神经保护作用的机制。方法将7日龄SD大鼠制备缺氧缺血脑损伤(HIBD)模型及rhEPO治疗模型,将假手术组作对照。测定各组新生鼠HI后6 h脑组织匀浆NO和NOS含量以及血浆ET水平。结果HIBD组在HI后6 h脑组织NO、NOS及血浆ET均升高(P<0.05),rhEPO组脑组织NO、NOS显著降低水平(P<0.05),而血浆ET含量无明显改变。结论外源性rhEPO可通过减少NO的过量生成而对HIBD后的脑组织起到保护作用。     

前列腺素E1对新生大鼠缺氧缺血性脑损伤的保护作用

目的探讨外源性前列腺素E1(PGE1)对缺氧缺血新生大鼠脑组织超氧化物歧化酶(SOD)和NO水平的影响。方法选用7日龄Wistar大鼠60只,制备缺氧缺血性脑损伤(HIBD)模型后注射PGE1及川芎嗪(TMP)。缺氧缺血后48h处死,取大脑皮质,制作脑组织匀浆,检测脑组织SOD、NO水平。结果HIBD组脑组织SOD水平低、NO水平高,同正常组对比均有显著差异(P均<0.01),PGE1、TMP治疗组SOD水平高、NO水平低,同HIBD组相比均有显著差异(P均<0.01)。结论PGE1可通过血脑脊液屏障使大脑皮质SOD水平升高,NO水平降低,对HIBD有防治作用。     

药物干预幼大鼠缺氧缺血性脑损伤与p53蛋白表达的研究

目的通过检测缺氧缺血性脑损伤(HIBD)幼大鼠脑组织中p53蛋白的表达和一氧化氮(NO)、一氧化氮合酶(NOS)、超氧化物歧化酶(SOD)含量,探讨HIBD的发病机制;了解神经节苷酯(GM1)和胞二磷胆碱干预对HIBD的影响。方法80只Wistar幼大鼠随机分四组;对照组、缺氧缺血组、GM1组、胞二磷胆碱组。17日龄制作HIBD模型,24 h后处死检测脑组织中p53蛋白的表达和NO、NOS、SOD含量及组织形态学的变化。结果缺氧缺血组NO、NOS含量高于其他三组(P<0.05);缺氧缺血组与胞二磷胆碱组SOD含量低于对照组和GM1组(P<0.05);缺氧缺血组p53蛋白表达高于其他三组(P<0.01),GM1和胞二磷胆碱组p53蛋白表达高于对照组(P<0.01);组织形态学改变显示,缺氧缺血组变性、坏死严重,GM1组与胞二磷胆碱组次之,对照组正常。结论NO和自由基引起的组织损伤可能诱导p53蛋白表达导致HIBD。GM1和胞二磷胆碱能改善脑组织NO、NOS、SOD含量和p53的表达,提示GM1和胞二磷胆碱对HIBD有一定的保护作用。     

雌激素对新生大鼠缺氧缺血脑损伤的干预作用

目的 研究外源性雌激素对缺氧缺血新生大鼠脑组织中超氧化酶歧化酶（SOD）和一氧化氮（NO）水平的影响,探讨雌激素治疗新生大鼠缺氧缺血性脑损伤（HIBD）的作用机制。方法 将7日龄Wistar大鼠75只随机分为正常组、HIBD模型组、生理盐水对照组（NS组）、丹参干预组（丹参组）及雌激素干预组（雌激素组）,制备HIBD模型后注射雌二醇2 mg/kg及丹参注射液（0.15 ml/10g）。缺氧缺血后72 h处死,取大脑皮质,制作脑组织匀浆,检测脑组织中SOD、NO水平。结果 HIBD组与NS组脑组织中SOD水平低、NO水平高,与正常组比较差异有统计学意义（P均〈0.01）;雌激素、丹参治疗组SOD水平高、NO水平低,与模型组比较差异有统计学意义（P均 〈 0.05）。结论 雌激素可通过血脑屏障,能使大脑皮质SOD水平升高,降低NO水平,对HIBD有防治作用。     

高压氧对新生大鼠缺氧缺血脑损伤模型脑组织神经细胞凋亡及超氧化物歧化酶和脂质过氧化物的影响

目的探讨高压氧(HBO)对新生大鼠缺氧缺血性脑损伤(HIBD)模型脑组织神经细胞凋亡和超氧化物歧化酶(SOD)、脂质过氧化物(MDA)的影响。方法新生7d龄健康SD大鼠随机分为4组:空白对照组(n=68),假手术组(分离左颈总动脉后不结扎直接缝合皮肤,n=66),HIBD组(模型制作采用经典的Rice法,n=60),HBO组(HIBD后行HBO治疗,1h/次/d,最长治疗7d,n=66)。TUNEL试剂盒检测脑组织凋亡的神经细胞,黄嘌呤氧化酶法测定SOD活力(nU/ml)和化学比色法测定MDA含量(μmol/L)。结果(1)缺氧缺血后不同时间HIBD组皮质和海马神经细胞凋亡明显增多,24h达高峰后逐渐下降;HBO组凋亡细胞数较HIBD组明显减少,但仍较空白对照组和假手术组高,差异有统计学意义(P<0.05);(2)缺氧缺血后HIBD组SOD含量下降,HBO治疗后SOD的含量较HIBD组升高,且随着治疗时间的延长SOD的水平逐渐升高,24h达高峰,然后逐渐下降,各组比较差异有统计学意义(P<0.05);(3)缺氧缺血后HIBD组MDA含量明显升高,18至24h达高峰,随着时间的推移逐渐下降;HBO治疗后MDA含量较HIBD组明显降低,差异有统计学意义(P<0.05)。结论HBO治疗可减轻HIBD后神经细胞凋亡,机制可能与HBO诱导脑组织SOD的表达,增强组织的抗氧化应激损伤有关。     

糖原合成酶激酶-3β和自由基在缺氧缺血性脑损伤新生大鼠细胞凋亡中的作用

目的 探讨糖原合成酶激酶-3β(GSK-3β)和自由基在缺氧缺血性脑损伤(HIBD)新生大鼠细胞凋亡中的作用.方法 80只7日龄新生Wistar大鼠随机分成对照组和缺氧缺血组.缺氧缺血组动物先行左侧颈总动脉结扎术,将动物置于37℃恒温的密闭容器中,吸入80 mL/L氧气和920 mL/L氮气的混合气体2.5 h,建立HIBD动物模型.分别于缺氧后6 h、24 h、48 h、72 h、5 d处死各组动物,采用流式细胞仪检测其脑组织神经元凋亡,分光光度法检测其超氧化物歧化酶(SOD)、丙二醛(MDA)水平和谷胱苷肽还原酶(GOD-PX)酶活力,ELISA法检测GSK-3β水平.结果 缺氧缺血组新生大鼠脑组织神经元凋亡率于缺氧缺血后6、24、48和72 h均明显高于对照组(Pa <0.05).缺氧缺血组MDA和GSK-3β水平于缺氧缺血后6、24、48和72 h显著高于对照组(Pa <0.05),至5 d 2组比较差异不显著.SOD水平和GOD-PX酶活力于缺氧缺血后6、24、48 h显著低于对照组(Pa <0.05).神经元凋亡率与MDA和GSK-3β水平呈正相关,与SOD水平和GOD-PX酶活力呈负相关.结论 新生大鼠HIBD后24～72 h为脑损伤高峰期,GSK-3β与自由基损伤参与了缺氧缺血后神经细胞的凋亡.     

γ一氨酪酸治疗新生大鼠缺氧缺血性脑损伤的实验研究

目的 探讨γ-氨酪酸对新生大鼠缺氧缺血性脑损伤(HIBD)的治疗作用.方法 采用Rice法制备新生大鼠HIBD模型,用γ-氨酪酸(GABA)灌服HIBD大鼠,用TUNEL法监测大鼠脑组织切片各时间点的细胞凋亡数,用化学方法检测各时间点血清中的超氧化物歧化酶(SOD),一氧化氮(NO),诱生型一氧化氮合酶(iNOS)的浓度.结果 (1)缺氧缺血(HI)组各时间点的细胞凋亡率均明显高于假手术对照组;72h时间点的细胞凋亡率最高.(2)GABA治疗组与HI组相比,各时间点的凋亡率均明显降低、SOD值明显升高.(3)发病早期6 h时间点HI、GABA两组与正常对照(N)组NO、iNOS浓度比较,差异无统计学意义.两组其余各时间点的NO、iNOS值均明显高于假手术正常对照组,HI、GABA两组比较,GABA各时间点的值均明显低于HI组.结论 应用γ-氨酪酸治疗HIBD大鼠,可明显降低HIBD新生大鼠的脑细胞凋亡率.     

缺血后处理对新生大鼠缺氧缺血性脑损伤的影响

目的探讨缺血后处理(IPostc)对新生大鼠缺氧缺血性脑损伤(HIBD)可能的神经保护作用及其机制。方法以7日龄SD大鼠为研究对象,随机分为假手术组、HIBD组、IPostcⅠ组(15 s再灌注/15 s夹闭×3个循环)及IPostcⅡ组(30 s再灌注/10 s夹闭×3个循环),每组根据缺氧缺血后时间分为0、6、12、24 h及48 h 5个亚组,每个亚组15只。应用右侧颈总动脉夹闭联合低氧(8%O2+92%N2)建立HIBD模型,监测脑组织形态学变化,比较超氧化物歧化酶(SOD)、丙二醛(MDA)、脑组织含水量及水通道蛋白4(AQP4)mRNA相对表达量随时间的变化规律。结果经缺氧缺血处理的大鼠均出现典型的神经行为学异常、形态学和生化指标的变化。IPostcⅠ组SOD活性显著改善,MDA含量降低,脑组织含水量及AQP4 mRNA相对表达量降低,在6 h以后作用显著,差异有统计学意义(P<0.05)。而IPostcⅡ组无明显改善作用。结论缺血后处理对新生大鼠HIBD具有一定的神经保护作用,其机制与减轻氧化应激损伤及脑水肿有关。     

γ-氨酪酸治疗新生大鼠缺氧缺血性脑损伤的实验研究

目的探讨γ-氨酪酸对新生大鼠缺氧缺血性脑损伤(HIBD)的治疗作用。方法采用Rice法制备新生大鼠HIBD模型,用γ-氨酪酸(GABA)灌服HIBD大鼠,用TUNEL法监测大鼠脑组织切片各时间点的细胞凋亡数,用化学方法检测各时间点血清中的超氧化物歧化酶(SOD),一氧化氮(NO),诱生型一氧化氮合酶(iNOS)的浓度。结果(1)缺氧缺血(HI)组各时间点的细胞凋亡率均明显高于假手术对照组;72h时间点的细胞凋亡率最高。(2)GABA治疗组与HI组相比,各时间点的凋亡率均明显降低、SOD值明显升高。(3)发病早期6h时间点HI、GABA两组与正常对照(N)组NO、iNOS浓度比较,差异无统计学意义。两组其余各时间点的NO、iNOS值均明显高于假手术正常对照组,HI、GABA两组比较,GABA各时间点的值均明显低于HI组。结论应用γ-氨酪酸治疗HIBD大鼠,可明显降低HIBD新生大鼠的脑细胞凋亡率。     

不同气体条件对腹膜形态影响的实验研究

目的 在体实验研究提示,CO2气腹后,腹膜结构出现改变.本实验研究不同气体条件对腹膜形态的影响,探讨CO2气腹对腹腔肿瘤细胞影响的潜在机制.方法 在体实验:乳猪14头,年龄7～14 d,体重2～4 kg.随机分为两组:CO2气腹组(CO2组,n=7),N2O气腹组(N2O组,n=7).分别行100%CO2及100%N2O气腹,气腹时间为4 h,气腹压力为12 mm Hg.实验结束,采集腹膜标本.离体实验:C57BL/6小鼠10只,年龄4周左右,经0.125%胰酶预处理后,通过腹腔灌洗分离培养小鼠腹膜间皮细胞.离体细胞随机分为三组:对照组(5%CO2组).100%CO2组,8 cm H2O压力100%CO2组.细胞培养至连续单层后,将细胞分别暴露于5%CO2、100%CO2及8cmH2O压力100%CO2中4 h.不同气体条件下腹膜及分离培养的间皮细胞行电镜观察.结果 在体实验腹膜电镜结果提示压力12 mm Hg的100%CO2气腹维持4 h,导致腹膜间皮细胞层破坏,基底膜暴露,仅存细胞骨架;相同条件的100%N2O气腹使间皮细胞间隙增大,部分区域基底膜暴露.离体实验观察100%CO2破坏间皮细胞微绒毛,压力下的100%CO2对问皮细胞影响更加明显.结论 100%CO2使在体腹膜及离体间皮细胞超微结构发生明显改变,因此,小鼠模型中发现的CO2气腹后神经母细胞瘤转移增加可能与间皮细胞屏障削弱有关.

Abstract：

Objective Electron microscopic studies have shown significant morphologic changes of peritoneum after CO2 pneumoperitoneum in vivo. This experiment was to assess the effect of different gas on the morphology of peritoneum and the underlying mechanism of CO2 pneumoperitoneum on tumor cells. Methods In vivo, fourteen piglets (2-4 kilogram in weight, 7-14 days of age) were equally divided into the CO2 group(n = 7) and N2O group(n = 7). 100% CO2 or 100% N2O pneumoperitoneum was infused for 4 hours. Pneumoperitoneum pressure was 12 mmHg. At the end of the experiment, the samples of peritoneum were collected. In vitro, primary murine peritoneal mesothelial cells were36 collected by peritoneal lavage from ten C57BL/6 mice (4 weeks of age) after 0. 125% trypsin pretreatment. Isolated cells were divided into three groups: control group (5% CO2),100% CO2 group and 8 cm H2O pressure &. 100% CO2 group. After monolayers of mesothelial cells were established, cells were cultured with 5%CO2, 100% CO2 and 100% CO2 with 8 cm H2O pressure for 4 hours. Peritoneum and isolated mesothelial cells were examined by scanning electron microscopy. Results Scanning electron microscopy investigation suggested in vivo, 12 mmHg 100% CO2 pneumoperitoneum for 4 hours destroyed mesothelial cells layer of peritoneum, exposing the basal lamina. In contrast, 100% N2O pneumoperitoneum leaded to an increase of intercellular gaps and the basal lamina was exposed in part areas under same pressure and duration. In vitro, 100% CO2 exposition was associated with a significant destruction of the microvilli formation of isolated mesothelial cells. 100% CO2 with 8 cm H2O pressure had more significant impact on mesothelial cells. Conclusions The peritoneal mesothelial cells lose their typical cell morphology when exposed to 100% CO2. Thus, the increased neuroblastoma metastasis observed after CO2 pneumoperitoneum in mice might be related to an impaired mesothelial barrier function.     

Update on Cochrane data on paediatric respiratory diseases

INTRODUCTION: Systematic reviews seek to describe and summarise the best evidence for a given intervention by pooling data from relevant quality clinical trials. The Cochrane Collaboration has fostered the development and dissemination of systematic reviews throughout the world. We have identified and summarised The Cochrane systematic reviews of relevance to the paediatric pulmonologist. METHODS: We performed an expert search of the Cochrane Database of Systematic Reviews using a combination of medical subject headings and free text terms relating to paediatric respiratory disease. RESULTS: The search identified 120 systematic reviews with interventions specific to children with some relevance to pulmonary disease, and 327 reviews with interventions relating to pulmonary disease in adults and children. After pragmatic exclusions, 81 reviews were sorted by disease and 59 of these are discussed in detail. CONCLUSIONS: There are now many systematic reviews that make a positive contribution to paediatric pulmonology. The majority of reviews (69%) found evidence that either confirmed or refuted an accepted practice. The remaining reviews concluded that the evidence for an accepted practice is poor and sometimes wholly absent. Clinicians must be aware that lack of evidence of effect is not the same as evidence of lack of effect. Caution must be exercised before applying the conclusions of systematic reviews based upon adult data to childhood disease.     

Passive smoking by asthmatics: its greater effect on boys than on girls and on older than on younger children

In 415 nonsmoking asthmatic children who were seen consecutively, asthma symptoms were more severe if the mother was a smoker than if she was a nonsmoker. This applied to both sexes but was more marked in boys than in girls. There were also other indications that sons were the more severely affected: the forced expiratory volume at 1 second, the forced expiratory flow rate during the middle half of the forced vital capacity, and the provocation concentration of histamine needed to result in a 20% decrease in the forced expiratory volume at 1 second were significantly decreased only in the sons, and lung function test results were significantly less in sons than in daughters of mothers who smoked. When the 415 children were stratified according to age, lung function improved significantly with increasing age in the children of nonsmokers; in children of smokers, by contrast, symptoms and lung function test results became progressively worse. As well, there was a correlation between these indications of asthma severity and the number of years the child had been exposed to the mother's smoke. It appeared that, compared with girls, boys were more sensitive to passive smoking, and that its adverse effect increased with age and with duration of exposure.     

Perspectives on dyslexia

Dyslexia, or a reading disability, occurs when an individual has significant difficulty with speed and accuracy of word decoding. Comprehension of text and spelling are also affected. The diagnosis of dyslexia involves the use of reading tests, but the continuum of reading performance means that any cutoff point is arbitrary. The IQ score does not play a role in the diagnosis of dyslexia. The cognitive difficulties of dyslexics include problems with speech perception, recognizing and manipulating the basic sounds in a language, language memory, and learning the sounds of letters. Dyslexia is a neurological condition with a genetic basis. There are abnormalities in the brains of dyslexic individuals. There are also differences in the electrophysiological and structural characteristics of the brains of dyslexics. Physicians play a particularly important role in recognizing children who are at risk for dyslexia and helping their parents obtain the proper assessment.