益赛普对脑外伤后核转录因子-κB、肿瘤坏死因子-α的表达及脑水肿的影响

目的 观察注射用重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白(rhTNFB:Fc,益赛普)对创伤性脑损伤后脑组织核转录因子-κB(NF-KB)和肿瘤坏死因子-α(TNF-α)的表达及对脑水肿的影响.方法 采用Feeney自由落体撞击法建立脑损伤模型,益赛普组大鼠于脑损伤模型建立后30 min腹腔注射益赛普3.0 mg/kg,对照组及创伤组大鼠注射生理盐水.采用放射免疫法检测大鼠脑组织匀浆TNF-α的蛋白表达,免疫组织化学法检测脑组织NF-κB的阳性细胞表达,用干湿重法测定大鼠脑组织含水量;并应用电镜技术进行脑组织病理形态学观察.结果 与对照组比较,大鼠脑损伤后脑组织NF-κB和TNF-α的表达及脑组织含水量均明显升高(P<0.05或P<0.01);与创伤组比较,益赛普治疗组大鼠NF-κB、TNF-α表达及脑组织含水量均显著降低(P<0.05,P<0.01).在电镜下观察,益赛普组大鼠脑组织损伤明显较创伤组大鼠轻.结论 大鼠急性脑损伤后脑组织NF-κB及TNF-α表达增加,并与脑水肿程度相平行;急性脑损伤后应用益赛普治疗可以抑制脑组织NF-κB和TNF-α的表达,减轻脑水肿.     

宫内感染致脑损伤幼鼠脑组织核因子-κB、肿瘤坏死因子-α表达的变化

目的:通过研究宫内感染致脑损伤幼鼠脑组织核因子-κB(NF-κB)及肿瘤坏死因子α(TNF-α)的表达情况,探讨NF-κB在脑损伤中的作用.方法:取孕龄17、18 d(足月为22.5 d)的SD大鼠,每次350 μg/kg,连续2 d腹腔注射脂多磷(LPS),构建宫内感染大鼠模型(LPS组);对照组(NS组)孕鼠腹腔注射同剂量的生理盐水.观察胎盘和仔鼠脑组织的病理改变.分别留取孕20、21 d(G20、G21)及生后1、3、7、14 d(P1、P3、P7、P14)的新生大鼠脑标本,检测NF-κB及TNF-α的表达情况.结果:LPS组新生大鼠脑组织HE染色可见细胞水肿,组织疏松,细胞数减少.蛋白表达结果显示LPS组NF-κB均值较NS组差异有显著性(F=47.844,P=0.002);LPS组TNF-α较NS组差异有显著性(F=16.863,P=0.015).LPS组NF-κB、TNF-αmRNA在G20、G21、P1、P3、P7的表达比NS组明显升高,差异有显著性(P<0.05),而在P14两组差异无显著性(P>0.05).结论:宫内感染后NF-κB信途径被激活,诱导炎性因子大量释放,最终导致脑损伤的发生.     

白介素-10对内毒素诱导肺泡巨噬细胞核因子-κB活化及肿瘤坏死因子释放的调节

目的 探讨白介素-10对内毒素(LPS)诱导肺泡巨噬细胞核因子-κB(NF-κB)活化及肿瘤坏死因子α(TNF-α)基因表达的调节,为临床运用白介素-10提供理论依据。方法 用支气管肺泡灌洗法收集肺泡巨噬细胞(PAM)进行培养,分正常对照组、LPS组、IL-10＋LPS组。用凝胶电泳迁移率改变分析(EMSA)法和ELISA法分别检测核提取物中NF-κB活性和细胞培养上清中TNF-α含量。结果 LPS组NF-κB活性和TNF-α含量在刺激后0.5～4h明显高于正常对照组;IL-10＋LPS组NF-κB活性和TNF-α含量均显著低于LPS组。结论 LPS诱导PAM的NF-κB活化,导致TNF-α基因表达增强;白介素-10可抑制NF-κB活化而减少TNF-α的释放。     

弥漫性脑损伤后大鼠肠黏膜上皮细胞的凋亡和核因子-κB的表达

目的 观察弥漫性脑损伤后大鼠肠黏膜上皮细胞凋亡以及核因子-κB（NF-κB）表达的动态变化，探讨两者在肠黏膜屏障功能障碍中的作用。方法 采用Marmarou模型致大鼠重型弥漫性脑损伤，150只雄性Wistar大鼠随机分成对照组和伤后1、2、4、8、12、24、48、72、168h组，共10组，利用免疫组化技术检测NF-κB在不同时相组的表达，采用原位末端标记（TUNEL）法计数不同时相组凋亡细胞。结果 致伤组NF-κB表达的积分光密度均显著大于对照组（P〈0．01）；伤后1h凋亡细胞数量即开始增加，于伤后12h达到峰值后逐渐下降，但直到168h均较对照组明显升高（P〈0.01）。结论 弥漫性脑损伤后激活NF-κB。肠黏膜上皮细胞凋亡增加，两者在肠黏膜屏障功能障碍发生中可能起重要作用。     

脂多糖对中性粒细胞核转录因子-κB活性的影响

目的：探讨在脂多糖（LPS）刺激下,中性粒细胞核转录因子-κB（NF-κB）活性变化及其抑制因子（IκBα）的影响。方法：离体培养人中性粒细胞,分为来普霉素B（LMB）干预组（A组）、LPS刺激组（B组）和LPM＋LPS组（C组）。各组分别在刺激后0、15、60、120min,用NF-κBp65试剂盒检测细胞核NF-κB活性,用Western-blot检测细胞核、浆中IκBα含量。结果：A组中各时相点NF-κB活性无明显变化;同一时相点细胞核、浆之间,以及不同时相点细胞核之间、细胞浆之间IκBα含量无明显变化。B组LPS刺激后,NF-κB活性较0点时明显增强;细胞核、浆中各时相点IκBα较未刺激时显著降低;细胞核、浆中呈现一致性变化。C组NF-κB活性于60min时点后,较B组同时相点明显受抑制;胞浆中IκBα于60min时较B组明显减少,而核中IκBα于60min后较B组明显增加。结论：NF-κB活性与核中IκBα含量呈负相关;IκBα在中性粒细胞存在核浆穿梭,通过抑制IκBα核浆穿梭,可显著降低NF-κB活性。     

RNA干扰介导的核转录因子-κB抑制蛋白激酶α和γ基因沉默对核转录因子-κB信号通路调节作用的影响

目的 观察RNA干扰介导的核转录因子-κB抑制蛋白(IκB)激酶(IKK)α和γ基因沉默对核转录因子-κB(NF-κB)信号通路的调节作用,进一步阐明其基因调控机制.方法 设计IKKα及IKKγ靶向的小分子干扰RNA(siRNA),合成互补的寡核苷酸链,转染到RAW264.7小鼠巨噬细胞.观察经脂多糖(LPS)刺激后NF-κB的活化、IKKα及IKKγ基因表达的变化、NF-κB p65及p50核移位的变化以及前体蛋白NF-κB p105的表达情况.结果 IKKα及IKKγ基因沉默后,可导致IKKα及IKKγ基因表达出现明显下调,同时NF-κB p65及p50的核移位受到抑制,胞质、胞核中NF-κB p65、p50及p105的表达显著下调,而且能抑制NF-κB p65、p50及p105蛋白的核移位.结论 IKKα及IKKγ两种蛋白激酶参与NF-κB信号通路的调节,不仅能分别在抑制蛋白的泛肽化、组蛋白磷酸化等环节发挥作用,而且还能够通过相互之间的协同作用,弥补其中某种蛋白受到过度抑制时所引起的炎症信号通路的功能障碍.     

高血压性大鼠脑出血后核因子-κB表达的变化

目的观察高血压性大鼠脑出血后血肿周围组织核因子-κB(NF-κB)的表达,分析其与出血时间的关系。方法取成年SD大鼠80只,体质量250~300 g,大鼠高血压性脑出血模型采用双侧肾动脉前支部分热凝,立体定位仪下自体血脑内注入法建立。随机分为对照组和脑出血组,采用电泳迁移率改变分析方法(EMSA)检测核内NF-κB的活性,用免疫组化方法观察NF-κB在细胞内的表达情况。结果大鼠高血压性脑出血后1 h后NF-κB即开始表达,24 h达到高峰,持续至72 h开始下降。结论高血压性脑出血后早期即有NF-κB的表达,并参与了脑出血后周围脑组织的继发性损伤。     

大黄对脓毒症大鼠核因子-kB活化的抑制作用

目的:探讨脓毒症时肠道组织肿瘤坏死因子-α(TNF-α)、单核细胞趋化蛋白-1(MCP-1)及核因子-κB(NF-κB)活性的相关性,揭示大黄治疗脓毒症的有效机制.方法:采用盲肠结扎穿孔术制备大鼠脓毒症模型.分别在术后1、3、6、12、24、48 h活杀大鼠取肠黏膜组织,用酶联免疫吸附法测TNF-α、MCP-1的含量,用凝胶电泳迁移法测NF-κB的活性.在脓毒症模型基础上加用大黄治疗,分别于治疗后12、24、48、72 h活杀大鼠,用同样的方法检测TNF-α、MCP-1含量及NF-κB活性. 结果:脓毒症大鼠肠黏膜NF-κB活性及TNF-α、MCP-1含量均较相应对照组明显升高(P均<0.01);大黄治疗后能明显抑制升高的NF-κB活性和TNF-α、MCP-1含量(P均<0.05).结论:TNF-α、MCP-1是脓毒症早期激活的细胞因子,其释放与NF-κB活性密切相关;大黄可通过抑制NF-κB活性、减少炎症细胞因子释放而达到抑制炎症反应的作用.     

急性胰腺炎患者核因子-κB激活的检测

目的探讨核因子-κB激活在急性胰腺炎患者血液中的表达与时间关系。方法急性胰腺炎患者20例,对照组12例。采用流式细胞术检测外周血中核因子-κB激活。结果胰腺炎组各时段(<24h、24~48h、48~72h、>72h核因子-κB激活明显高于对照组,P<0.05。24h内核因子-κB明显激活(54.07±18.17)%;24~48h达高峰(70.03±5.62)%,48h以后逐渐减弱,一周后NF-κB激活向正常水平接近。对照组各时段核因子-κB激活不明显(P>0.05)。结论急性胰腺炎患者早期外周血中NF-κB明显激活。可望应用NF-κB抑制剂抑制NF-κB激活,控制急性胰腺炎的进展。     

一氧化氮和白介素-10抑制核因子-κB活化的实验研究

目的探讨一氧化氮(NO)和白介素-10(IL-10)对内毒素(LPS)诱导的肺泡巨噬细胞核因子-κB(NF-κB)活化的调节,为临床运用提供理论依据.方法用支气管肺泡灌洗法收集肺泡巨噬细胞(PAM)进行培养,分正常对照组、LPS组、NO+LPS组和IL-10+LPS组.用凝胶电泳迁移率改变分析(EMSA)法和ELISA法分别检测提取物中NF-κB活性和细胞培养上清中TNF-α含量.结果 LPS组NF-κB活性和TNF-α含量在刺激后0.5～4 h显著高于正常对照组(P＜0.01);NO+LPS组和IL-10+LPS组的NF-κB活性和TNF-α含量与LPS组相比均明显下降,尤在刺激后1 h最显著(P＜0.01).结论 LPS诱导PAM的NF-κB活化,导致TNF-α基因表达增强;NO和IL-10可抑制NF-κB活化,减少TNF-α的释放,缓解LPS诱导的ALI.     

Imaging brain development: the adolescent brain

The past 15 years have seen a rapid expansion in the number of studies using neuroimaging techniques to investigate maturational changes in the human brain. In this paper, I review MRI studies on structural changes in the developing brain, and fMRI studies on functional changes in the social brain during adolescence. Both MRI and fMRI studies point to adolescence as a period of continued neural development. In the final section, I discuss a number of areas of research that are just beginning and may be the subject of developmental neuroimaging in the next twenty years. Future studies might focus on complex questions including the development of functional connectivity; how gender and puberty influence adolescent brain development; the effects of genes, environment and culture on the adolescent brain; development of the atypical adolescent brain; and implications for policy of the study of the adolescent brain.     

Mediators of brain edema and secondary brain damage

Progress is our understanding of the roles of vasogenic and cytotoxic brain edema in secondary brain damage can be expected from studies of the ability of biochemical factors to open the blood-brain barrier, derange the microcirculation, and cause cell swelling and necrosis. Mediator compounds are considered to form or to become released in an area of primarily damaged brain (necrosis) and to enter the cerebral parenchyma through the broken blood-brain barrier from the intravascular space. Many biochemical factors must be considered. We suggested three criteria for determining the roles of mediators: a) they must inflict brain tissue damage, b) they must occur in pathologic concentrations or in compartments not normally present, and c) specific inhibition should attenuate secondary brain damage. These requirements are met by the kallikrein-kinin system and by glutamate. In the case of arachidonic acid and its many metabolites, the concept is difficult to test because fatty acids may be active only if not bound to proteins, and therapeutic inhibition might be difficult. A variety of mediators may enhance each other in a cascade manner by various initiating reactions that might be amenable for pharmacologic inhibition.     

Hypoglycemia, functional brain failure, and brain death

Hypoglycemia commonly causes brain fuel deprivation, resulting in functional brain failure, which can be corrected by raising plasma glucose concentrations. Rarely, profound hypoglycemia causes brain death that is not the result of fuel deprivation per se. In this issue of the JCI, Suh and colleagues use cell culture and in vivo rodent studies of glucose deprivation and marked hypoglycemia and provide evidence that hypoglycemic brain neuronal death is in fact increased by neuronal NADPH oxidase activation during glucose reperfusion (see the related article beginning on page 910). This finding suggests that, at least in the setting of profound hypoglycemia, therapeutic hyperglycemia should be avoided.     

Anemia and brain oxygen after severe traumatic brain injury

Purpose

To investigate the relationship between hemoglobin (Hgb) and brain tissue oxygen tension (PbtO₂) after severe traumatic brain injury (TBI) and to examine its impact on outcome.

Methods

This was a retrospective analysis of a prospective cohort of severe TBI patients whose PbtO₂ was monitored. The relationship between Hgb—categorized into four quartiles (≤9; 9–10; 10.1–11; >11?g/dl)—and PbtO₂ was analyzed using mixed-effects models. Anemia with compromised PbtO₂ was defined as episodes of Hgb?≤?9?g/dl with simultaneous PbtO₂?Results We analyzed 474 simultaneous Hgb and PbtO₂ samples from 80 patients (mean age 44?±?20?years, median GCS 4 (3–7)). Using Hgb?>?11?g/dl as the reference level, and controlling for important physiologic covariates (CPP, PaO₂, PaCO₂), Hgb?≤?9?g/dl was the only Hgb level that was associated with lower PbtO₂ (coefficient ?6.53 (95?% CI ?9.13; ?3.94), p?2?p?=?0.008), controlling for age, GCS, Marshall CT grade, and APACHE II score.

Conclusions

In this cohort of severe TBI patients whose PbtO₂ was monitored, a Hgb level no greater than 9?g/dl was associated with compromised PbtO₂. Anemia with simultaneous compromised PbtO₂, but not anemia alone, was a risk factor for unfavorable outcome, irrespective of injury severity.     

Effect of brain cooling on brain ischemia and damage markers after fluid percussion brain injury in rats

Although systemic cooling had recently been reported as effective in improving the neurological outcome after traumatic brain injury, several problems are associated with whole-body cooling. The present study was conducted to test the effectiveness of brain cooling without interference with the core temperature in rats after fluid percussion traumatic brain injury (TBI). Brain dialysates ischemia (e.g., glutamate and lactate-to-pyruvate ratio) and injury (e.g., glycerol) markers before and after TBI were measured in rats with mild brain cooling (33 degrees C) and in the sham control group. Brain cooling was accomplished by infusion of 5 mL cold saline via the external jugular vein under general anesthesia. The weight loss was determined by the difference between the first and third day of body weight after TBI. The maximum grip angle in an inclined plane was measured to determine motor performance, whereas the percentage of maximal possible effect was used to measure blockade of proprioception. The triphenyltetrazolium chloride staining procedures were used for cerebral infarction assay. As compared with those of the sham-operated controls, the animals with TBI had higher values of extracellular levels of glutamate, lactate-to-pyruvate ratio, and glycerol in brain and intracranial pressure, but lower values of cerebral perfusion pressure. Brain cooling adopted immediately after TBI significantly attenuated the TBI-induced increased cerebral ischemia and injury markers, intracranial hypertension, and cerebral hypoperfusion. In addition, the TBI-induced cerebral infarction, motor and proprioception deficits, and body weight loss evaluated 3 days after TBI were significantly attenuated by brain cooling. We successfully demonstrate that brain cooling causes attenuation of TBI in rats by reducing cerebral ischemia and injury resulting from intracranial hypertension and cerebral hypoperfusion. Because jugular venipuncture is an easy procedure frequently used in the emergency department, for preservation of brain function, jugular infusion of cold saline may be useful in resuscitation for trauma patients.     

Enhanced brain extraction improves the accuracy of brain atrophy estimation

BET (Brain Extraction Tool) is a widely used computer program to automatically separate brain from non-brain structures in MR images. This procedure is used in SIENAX and SIENA, which are robust approaches to quantifying brain volume (atrophy state) and volume change (atrophy rate), respectively. Occasionally, however, BET produces imperfect results (e.g., inclusion of non-brain structures). This is usually either ignored (if inaccuracies are small) or corrected by manual adjustment, with the disadvantages of user intervention. We describe here a new, automated option in BET. This is based on the original BET, but uses standard-space masking to remove tissue around the eyes, and further morphological operations and thresholding to refine eyeball removal and eliminate additional non-brain tissues. To assess whether the new BET procedure improves brain volume measurements, this was compared with the traditional and manual editing procedures in SIENA and SIENAX. Measures of atrophy rate and state were significantly higher with the traditional procedure than with the manual editing and new procedures. In contrast, both atrophy measures were almost identical and highly correlated when the manual editing and new procedures were used. The voxels excluded with these two procedures showed close overlap, as judged by the Dice overlap coefficient. We conclude that, in SIENA and SIENAX, the proposed BET procedure shows results matching those obtained after manual editing, thus more closely approximating the "true" brain volume. Multicentre studies monitoring brain atrophy in clinical trials may receive benefit by using this unbiased, fully automated procedure.