右美托咪定联合氯胺酮的最佳麻醉浓度研究

目的:探寻患儿室间隔缺损封堵术中右美托咪定(dexmedetomidine,Dex)联合氯胺酮的最佳麻醉浓度。方法:选择4~11岁拟行VSDO的室间隔缺损患儿120例,随机分为A、B、C三组(n=40)。静脉注射阿托品及氯胺酮(1.0mg·kg-1)行麻醉诱导后,输注10min右美托咪定负荷量0.5μg·kg~(-1),然后对A、B、C三组分别静脉输注0.8、1.0、1.2μg·kg-1·h-1的右美托咪定。术中若麻醉变浅,单次追加氯胺酮0.5mg·kg-1。分别记录入室(T_0)、氯胺酮给药后1min(T_1)、5min(T_2)、输注完毕(T_3)、输注维持量15min(T_4)、术毕(T_5)、苏醒时(T_6)的BIS、BP、HR和SpO2,手术时间、苏醒时间,呼吸抑制和术后躁动等不良反应,氯胺酮总用量,氯胺酮和阿托品的追加情况。结果:与同组T_0时相比,三组在T_4和T_5的BIS值降低,三组的BP值、SpO2值在T_1~T_6无统计学差异。A组的HR在T_4、T_5无统计学差异(t=0.525,P=0.601)。三组手术时间和苏醒时间无统计学差异。B、C组的氯胺酮总用量和追加率、呼吸抑制发生率无统计学差异,均低于A组。B、C两组之间阿托品追加率有统计学差异,均高于A组。三组的苏醒期躁动发生率均为零。结论:4~11岁患儿室间隔缺损封堵术中,采用1.0mg·kg~(-1)氯胺酮行麻醉诱导,再以右美托咪定0.5μg·kg~(-1)的负荷量输注、1.0μg·kg~(-1)·h~(-1)的浓度维持,可使麻醉效果良好,且不良反应少,是最佳的联合麻醉浓度。     

右美托咪定对脑肿瘤手术患者细胞免疫功能以及预后影响的研究

目的:探讨右美托咪定(Dex)对脑肿瘤手术患者细胞免疫功能及预后的影响。方法:选择2013年1月-2016年1月本院60例行脑肿瘤手术的患者,随机分为实验组和对照组,各30例。实验组患者进入手术室后静脉泵入Dex,对照组给予0.9%氯化钠溶液,观察比较两组在手术前(T0)、手术开始后1h(T1)、术后1h(T2)、术后24 h(T3)四个时期的C反应蛋白(CRP)、T细胞亚群值、自然杀伤细胞(NK)数量、以及IL-2、IL-6、IL-10浓度。随访1年观察患者复发情况。结果:实验组T2期的CD3、CD4、CD4/CD8水平显著低于T0,差异有统计学意义(P0.05)。实验组T2期的CD4、CD4/CD8水平明显高于对照组,差异有统计学意义(P0.05)。对照组T2、T3的NK值显著低于T0期,实验组T2时的NK值显著高于对照组,差异有统计学意义(P0.05)。两组T1、T2、T3的血清CRP水平显著高于T0,且实验组显著低于对照组,差异均有统计学意义(P0.05)。对照组IL-2在T1、T2期的水平显著低于T0期,且实验组显著高于对照组,差异均有统计学意义(P0.05)。实验组IL-6在T2、T3期显著低于T0期,对照组IL-6在T1、T2、T3期水平显著低于T0期,且实验组在T1、T2、T3期明显低于对照组。对照组IL-10在T2、T3期高于T0期,且实验组在T2、T3期显著低于对照组,差异均有统计学意义(P0.05)。两组1年内总复发率比较,差异有统计学意义(P0.05)。结论:脑肿瘤切除手术应激及麻醉可能导致细胞免疫功能下降,Dex可以改善细胞免疫功能,有利于手术患者的康复及预后。     

右美托咪定术后持续泵注对老年肺癌患者术后心律失常的影响

目的:观察右美托咪定术后持续泵注对老年肺癌患者术后心律失常的影响。方法:选取在我院胸科接受手术治疗的肺癌患者100例,随机分成2组(n=50):地佐辛+氟比洛芬酯组(A组)和地佐辛+氟比洛芬酯+右美托咪定组(B组)。手术结束前半小时静注地佐辛5 mg和氟比洛芬酯100 mg,术毕连接患者自控镇痛泵(PCIA)。A组中加入地佐辛20 mg和氟比洛芬酯300 mg,而B组中加入地佐辛20 mg和氟比洛芬酯300 mg和80μg的右美托咪定。观察并记录患者术后4 h,8 h,24 h和48 h的VAS疼痛评分、Ramsay镇静评分及不良反应(维持VAS评分≤4分,Ramsay评分2~4分),监测心电图,记录心律失常发生情况。结果:A、B两组术后疼痛、镇静分级、不良反应发生率的差异无统计学意义。A组中17例患者术后发生心律失常,明显高于B组(4例)(P0.05)。结论:右美托咪定可减少老年肺癌患者术后心律失常的发生,且无明显不良反应。     

右美托咪定对生理功能的影响和在临床中的应用

盐酸右美托咪定(dexmedetomidine hydrochloride,Dex))是一种新型α2肾上腺受体激动剂,该药可明显减少麻醉药和阿片类药用量,减轻气管插管及外科手术刺激的血流动力学反应,抑制交感神经反应,增加麻醉期间的循环稳定性,减少麻醉恢复期激动和恶心,是很有前途的麻醉辅助药。该药对缺血的心肌具有保护作用,对呼吸的影响较小,具有镇静、镇痛及抗焦虑作用,还可以降低危重患者的炎症反应以及抗抽搐等作用。右美托咪定还可以对颅内肿瘤切除术期间语言区定位提供良好的镇静作用,在临床中的应用越来越广泛。     

右美托咪定预处理对小鼠肠缺血再灌注损伤的作用研究

目的:右美托咪定(Dexmedetomidine,Dex)属于α-2肾上腺素能受体激动剂具有抗焦虑、催眠、镇痛和交感神经阻滞作用。最新研究发现右美托咪定对心脏和肺的缺血再灌注损伤具有显著的保护效应,但是右美托咪定是否对肠缺血再灌注损伤具有保护作用,迄今为止还没有相关研究。因此,本研究以小鼠为模型,观察右美托咪定预处理对小鼠肠缺血再灌注损伤的影响。方法:建立肠缺血再灌注损伤小鼠模型,并分为假手术组、缺血再灌注组和右美托咪定与处理组。不同剂量(10,25,50和100μg/kg)右美托咪定预处理小鼠。提取小鼠肠组织,用不同的试剂盒分别测定超氧化物歧化酶(Superoxide Dismutase,SOD),丙二醛(Malondialdehyde,MDA),谷胱甘肽(Glutathione,GSH),一氧化氮(Nitric Oxide,NO)和髓过氧化物酶(Myeloperoxidase,MPO)的水平变化。结果:右美托咪定预处理可以显著提高肠缺血再灌注损伤小鼠的存活率并呈剂量依赖性。右美托咪定预处理(100μg/kg)抑制由肠缺血再灌注损伤引起的不良效应,包括SOD水平降低,MDA水平升高,GSH水平降低,NO水平升高和MPO水平升高。结论:我们的研究表明右美托咪定可以提高小鼠肠缺血再灌注损伤的生存率,并且抑制氧化应激反应,炎症细胞的活化和侵润以及NO的水平,对肠缺血再灌注损伤具有显著的保护效应。本研究不仅进一步证实了右美托咪定的广泛的药理活性,而且为肠缺血再灌注损伤的治疗提供了潜在的治疗药物,其进一步的药理效应和作用机制值得进一步的研究。     

右美托咪定的临床麻醉应用进展

右美托咪定(dexmedetomidine,Dex)是高选择性α2-肾上腺素受体激动剂,具有镇静、镇痛、抑制交感神经活性、无呼吸抑制等药理性质。多项研究证实:围术期或ICUs住院期间给予患者右美托咪定,可以增加患者机械通气耐受力,减少机械通气时间,改善患者病情恢复,减少呼吸抑制,稳定血流动力学,减少麻醉剂用量及降低麻醉剂不良反应发生率,抑制应激反应,保护肺脏、神经功能、心脏功能,降低谵妄发生率,抗寒颤等作用特点。虽然右美托咪定存在心动过缓及低血压等不良反应,故应控制给药速度、剂量,合理用药在以便循环波动可控范围内。目前,右美托咪定可用于重症监护病房(ICUs)、全身麻醉、区域麻醉、小儿麻醉、日间手术及无痛检查等辅助用药。本文主要对右美托咪定的临床麻醉应用做以下介绍。     

单纯右美托咪定滴鼻与水合氯醛复合右美托咪定滴鼻在脑瘫患儿MRI检查中的应用效果比较

目的:比较单纯右美托咪定滴鼻与水合氯醛复合右美托咪定滴鼻在脑瘫患儿核磁共振成像(MRI)检查中的应用效果。方法:收集我院2015年1月到2016年7月收治的160例脑瘫患儿,按照就诊号排序后取随机数字分为单纯组和复合组,每组各80例。单纯组给予右美托咪定2μg/kg滴鼻+生理盐水口服(0.1 mL/kg),复合组给予口服水合氯醛50 mg/kg+右美托咪定(2μg/kg)滴鼻,采用密歇根大学小儿镇静评分(UMSS)评价镇静效果、镇静成功率,检测和比较两组患儿给药前后心率(HR)、血氧饱和度(SpO_2)、呼吸频率(RR)及入睡时间、苏醒时间、检查时间与父母分离时间等。结果:给药前,两组UMSS评分比较差异无统计学意义(P0.05),给药15 min、30 min,复合组UMSS评分明显高于单纯组(P0.05);给药30 min时,复合组镇静成功率为98.8%,单纯组为91.3%,差异具有统计学意义(P0.05);两组给药前后HR、SpO_2、RR水平比较差异均无统计学意义(P0.05)。单纯组入睡、苏醒、检查时间及与父母分离时间长于复合组(P0.05)。结论:水合氯醛复合右美托咪定滴鼻在脑瘫患儿MRI检查中的镇静效果明显优于单纯右美托咪定滴鼻。     

不同剂量右美托咪定联合七氟烷吸入诱导麻醉对宫腔镜手术患者血气及诱导期的影响

目的:研究不同剂量右美托咪定联合七氟烷吸入诱导麻醉对宫腔镜手术患者诱导期及血气指标的影响。方法:选取本院收治的60例宫腔镜手术患者,观察组20例在诱导麻醉之前,予以0.5μg/Kg的右美托咪定;对比组A的20例予以1.0μg/Kg的右美托咪定,对比组B的20例则仅泵注生理盐水,观察并比较各组血气指标变化和诱导期情况。结果:各组患者血气指标有显著性差异,其中,对比组B患者T2时的MAP(69.6±13.2 mm Hg)明显低于T0,各组BIS60时间有显著差异,对比组A成功置入喉罩时的CETSEV明显低于对比组B,组间差异显著P0.05。结论:予以0.5μg/Kg的右美托咪定联合七氟烷吸入诱导麻醉的效果较好,其可在保留患者自主呼吸前提之下,顺利完成喉罩置入,患者各项血气指标也较为稳定,具有重要意义。     

右美托咪定对子宫肌瘤切除术患者全麻苏醒期应激反应的影响

目的:探讨盐酸右美托咪定用于全凭静脉麻醉对子宫肌瘤切除术患者应激反应的影响。方法:选择我院收治的择期行子宫肌瘤切除术患者60例,随机分为观察组和对照组,每组30例。两组患者均采用全麻,其中观察组患者在麻醉诱导15 min内静脉输注1 ug/kg盐酸右美托咪定注射液,术中0.3-0.6 ug/(kg×h)维持;而对照组患者采用静脉输注0.9%的Nacl溶液。分别于麻醉前、麻醉后及苏醒期测定并观察两组患者外周静脉血中TNF-α,IL-2和IL-6的浓度变化情况。结果:两组患者麻醉前TNF-α,IL-2和IL-6的浓度无显著性差异(P0.05)。两组患者麻醉后及苏醒期TNF-α,IL-2及IL-6浓度均显著高于麻醉前,差异具有统计学意义(P0.05)。观察组患者麻醉后及苏醒期TNF-α,IL-2及IL-6浓度均显著低于对照组,差异具有统计学意义(P0.05)。结论:右美托咪定用于全凭静脉麻醉对子宫肌瘤切除术患者血清TNF-α、IL-2和IL-6浓度具有调节作用,可缓解或降低手术引起的应激反应。     

G-protein-coupled receptor kinase interactor-1 (GIT1) is a new endothelial nitric-oxide synthase (eNOS) interactor with functional effects on vascular homeostasis

Endothelial cell nitric-oxide (NO) synthase (eNOS), the enzyme responsible for synthesis of NO in the vasculature, undergoes extensive post-translational modifications that modulate its activity. Here we have identified a novel eNOS interactor, G-protein-coupled receptor (GPCR) kinase interactor-1 (GIT1), which plays an unexpected role in GPCR stimulated NO signaling. GIT1 interacted with eNOS in the endothelial cell cytoplasm, and this robust association was associated with stimulatory eNOS phosphorylation (Ser(1177)), enzyme activation, and NO synthesis. GIT1 knockdown had the opposite effect. Additionally, GIT1 expression was reduced in sinusoidal endothelial cells after liver injury, consistent with previously described endothelial dysfunction in this disease. Re-expression of GIT1 after liver injury rescued the endothelial phenotype. These data emphasize the role of GPCR signaling partners in eNOS function and have fundamental implications for vascular disorders involving dysregulated eNOS.     

Distribution and Significance of Nitric Oxide Synthase in Brain Tissues of Rats Exposed to Deltamethrin Insecticide

The distribution of nitric oxide synthase(NOS)in brain tissues of rats exposed to deltamethrininsecticide has been examined by histochemical NADPH-diaphorase staining techniques on frozen sec-tions.After injection of deltamethrin(12.5mg/kg,i.p.),a reproducible sequence of toxic signs ofhyperexcitability were elicited.The observation and image analysis showed that,within brain sec-tions of rats exposed to deltamethrin,the numbers and the total staining areas of the NOS positiveneurons were greatly increased,especially in cerebral cortex,hippocampal formation and paraventric-ular nucleus.In addition,the density of single neuron and the processes were also increased.The re-sults suggested that deltamethrin may induce the NOS expression or activate the NOS activity.TheNOS activation may involve in the chains responsible for the excitatory neurotoxicities induced bydeltamethrin.     

Endothelial Nitric-oxide Synthase (eNOS) Is Activated through G-protein-coupled Receptor Kinase-interacting Protein 1 (GIT1) Tyrosine Phosphorylation and Src Protein

Nitric oxide (NO) is a critical regulator of vascular tone and plays an especially prominent role in liver by controlling portal blood flow and pressure within liver sinusoids. Synthesis of NO in sinusoidal endothelial cells by endothelial nitric-oxide synthase (eNOS) is regulated in response to activation of endothelial cells by vasoactive signals such as endothelins. The endothelin B (ET_B) receptor is a G-protein-coupled receptor, but the mechanisms by which it regulates eNOS activity in sinusoidal endothelial cells are not well understood. In this study, we built on two previous strands of work, the first showing that G-protein βγ subunits mediated activation of phosphatidylinositol 3-kinase and Akt to regulate eNOS and the second showing that eNOS directly bound to the G-protein-coupled receptor kinase-interacting protein 1 (GIT1) scaffold protein, and this association stimulated NO production. Here we investigated the mechanisms by which the GIT1-eNOS complex is formed and regulated. GIT1 was phosphorylated on tyrosine by Src, and Y293F and Y554F mutations reduced GIT1 phosphorylation as well as the ability of GIT1 to bind to and activate eNOS. Akt phosphorylation activated eNOS (at Ser¹¹⁷⁷), and Akt also regulated the ability of Src to phosphorylate GIT1 as well as GIT1-eNOS association. These pathways were activated by endothelin-1 through the ET_B receptor; inhibiting receptor-activated G-protein βγ subunits blocked activation of Akt, GIT1 tyrosine phosphorylation, and ET-1-stimulated GIT1-eNOS association but did not affect Src activation. These data suggest a model in which Src and Akt cooperate to regulate association of eNOS with the GIT1 scaffold to facilitate NO production.     

Functional significance of cytosolic endothelial nitric-oxide synthase (eNOS): regulation of hyperpermeability

Endothelial NOS (eNOS)-derived NO is a key factor in regulating microvascular permeability. We demonstrated previously that eNOS translocation from the plasma membrane to the cytosol is required for hyperpermeability. Herein, we tested the hypothesis that eNOS activation in the cytosol is necessary for agonist-induced hyperpermeability. To study the fundamental properties of endothelial cell monolayer permeability, we generated ECV-304 cells that stably express cDNA constructs targeting eNOS to the cytosol or plasma membrane. eNOS-transfected ECV-304 cells recapitulate the eNOS translocation and permeability properties of postcapillary venular endothelial cells (Sánchez, F. A., Rana, R., Kim, D. D., Iwahashi, T., Zheng, R., Lal, B. K., Gordon, D. M., Meininger, C. J., and Durán, W. N. (2009) Proc. Natl. Acad. Sci. U.S.A. 106, 6849-6853). We used platelet-activating factor (PAF) as a proinflammatory agonist. PAF activated eNOS by increasing phosphorylation of Ser-1177 and inducing dephosphorylation of Thr-495, increasing NO production, and elevating permeability to FITC-dextran 70 in monolayers of cells expressing wild-type and cytosolic eNOS. PAF failed to increase permeability to FITC-dextran 70 in monolayers of cells transfected with eNOS targeted to the plasma membrane. Interestingly, this occurred despite eNOS Ser-1177 phosphorylation and production of comparable amounts of NO. Our results demonstrate that the presence of eNOS in the cytosol is necessary for PAF-induced hyperpermeability. Our data provide new insights into the dynamics of eNOS and eNOS-derived NO in the process of inflammation.     

Surface Charges and Regulation of FMN to Heme Electron Transfer in Nitric-oxide Synthase

The nitric-oxide synthases (NOS, EC 1.14.13.39) are modular enzymes containing attached flavoprotein and heme (NOSoxy) domains. To generate nitric oxide (NO), the NOS FMN subdomain must interact with the NOSoxy domain to deliver electrons to the heme for O₂ activation during catalysis. The molecular basis and how the interaction is regulated is unclear. We explored the role of eight positively charged residues that create an electropositive patch on NOSoxy in enabling the electron transfer by incorporating mutations that neutralized or reversed their individual charges. Stopped-flow and steady-state experiments revealed that individual charges at Lys⁴²³, Lys⁶²⁰, and Lys⁶⁶⁰ were the most important in enabling heme reduction in nNOS. Charge reversal was more disruptive than neutralization in all cases, and the effects on heme reduction were not due to a weakening in the thermodynamic driving force for heme reduction. Mutant NO synthesis activities displayed a complex pattern that could be simulated by a global model for NOS catalysis. This analysis revealed that the mutations impact the NO synthesis activity only through their effects on heme reduction rates. We conclude that heme reduction and NO synthesis in nNOS is enabled by electrostatic interactions involving Lys⁴²³, Lys⁶²⁰, and Lys⁶⁶⁰, which form a triad of positive charges on the NOSoxy surface. A simulated docking study reveals how electrostatic interactions of this triad can enable an FMN-NOSoxy interaction that is productive for electron transfer.     

激光生物学技术研究高脂血症大鼠红细胞变形能力改变及其机制

目的:通过研究红细胞膜流动性以及红细胞骨架结构的改变,进一步探讨高脂血症大鼠红细胞变形能力改变的机制。方法:16只Wistar大鼠随机分为两组:高血症组和对照组。高脂组给予高脂饮食。16周后,腹主动脉采血,采用酶比色法检测血浆甘油三脂、胆固醇含量;并利用激光衍射法测定红细胞变形指数、取向指数,荧光偏振法测定红细胞膜流动性,激光共聚焦显微镜观测红细胞骨架改变和红细胞F-actin的含量。结果:发现高脂血症大鼠红细胞的变形指数、取向指数以及红细胞膜的流动性显著降低(P<0.05),红细胞形态和骨架发生改变,F-actin含量显著降低(P<0.05)。结论:高脂血症大鼠红细胞变形能力降低与红细胞膜结构改变有一定的关系。     

低强度氦氖激光对缺血性疾病患者红细胞变形性影响的临床研究

目的：探讨低强度氦氖激光对临床中风等缺血性疾病患者红细胞变形能力影响情况。方法：临床采集不同缺血性疾病患者新鲜血样,检测各组红细胞变形能力情况。对中风患者血样进一步分组,给予不同剂量的氦氖激光处理,讨论临床低强度氦氖激光量效关系,探讨具有临床疗效的有效剂量情况。结果：各疾病病组红细胞变形能力较正常对照组红细胞变形能力为低;缺血疾病组样品经低强度氦氖激光照射后,其红细胞变形能力较未经激光照射组有显著不同。结论：显示体外人红细胞变形能力因患者疾病情况、红细胞状态、低强度氦氖激光临床治疗输出功率等因素有不同。     

A Pivotal Role for Tryptophan 447 in Enzymatic Coupling of Human Endothelial Nitric Oxide Synthase (eNOS): EFFECTS ON TETRAHYDROBIOPTERIN-DEPENDENT CATALYSIS AND eNOS DIMERIZATION*

Tetrahydrobiopterin (BH4) is a required cofactor for the synthesis of NO by NOS. Bioavailability of BH4 is a critical factor in regulating the balance between NO and superoxide production by endothelial NOS (eNOS coupling). Crystal structures of the mouse inducible NOS oxygenase domain reveal a homologous BH4-binding site located in the dimer interface and a conserved tryptophan residue that engages in hydrogen bonding or aromatic stacking interactions with the BH4 ring. The role of this residue in eNOS coupling remains unexplored. We overexpressed human eNOS W447A and W447F mutants in novel cell lines with tetracycline-regulated expression of human GTP cyclohydrolase I, the rate-limiting enzyme in BH4 synthesis, to determine the importance of BH4 and Trp-447 in eNOS uncoupling. NO production was abolished in eNOS-W447A cells and diminished in cells expressing W447F, despite high BH4 levels. eNOS-derived superoxide production was significantly elevated in W447A and W447F versus wild-type eNOS, and this was sufficient to oxidize BH4 to 7,8-dihydrobiopterin. In uncoupled, BH4-deficient cells, the deleterious effects of W447A mutation were greatly exacerbated, resulting in further attenuation of NO and greatly increased superoxide production. eNOS dimerization was attenuated in W447A eNOS cells and further reduced in BH4-deficient cells, as demonstrated using a novel split Renilla luciferase biosensor. Reduction of cellular BH4 levels resulted in a switch from an eNOS dimer to an eNOS monomer. These data reveal a key role for Trp-447 in determining NO versus superoxide production by eNOS, by effects on BH4-dependent catalysis, and by modulating eNOS dimer formation.     

Effect of subchronic acrylamide exposure on the expression of neuronal and inducible nitric oxide synthase in rat brain

Acrylamide (ACR) is a known industrial neurotoxic chemical. Evidence suggests that ACR neurotoxic effect is related to brain neurotransmission disturbances. Since nitric oxide (NO) acts as a neurotransmission modulator and is produced by nitric oxide synthase (NOS), the neuronal NOS (nNOS) and inducible NOS (iNOS) expression pattern were determined in rat cerebral cortex and striatum after subchronic exposure to ACR. Using immunocytochemistry, the neuronal count of nNOS or optical density of iNOS from sections at three coronal levels, bregma 1.0, -0.4, and -2.3 mm, were compared between ACR-treated and control rats. At all three levels, nNOS expressions were uniformly decreased in most of the neocortical subregions following the treatment of ACR. At bregma level 1.0 mm, total numbers of nNOS expressing neurons were significantly decreased to 58.7% and 64.7% of the control in the cortex and striatum of ACR-treated rats, respectively. However, at the bregma level -2.3 mm, ACR treatment did not produce a significant difference in the numbers of nNOS expressing neurons both in the cortex and striatum. Contrary to nNOS, iNOS expressions were consistently increased to approximately 32% in the neocortex and 25% in the striatum, following the subchronic ACR treatment. These data suggest that subchronic ACR exposure involves compensatory mechanism on nNOS and iNOS expression to maintain the homeostasis of NO at the rostral part of the neocortex and the striatum. However, in the caudal brain, increased iNOS expression did not suppress nNOS expression. Therefore, the present study is consistent with the hypothesis that ACR toxicity is mediated through the disturbance to the NO signaling pathway and exhibits a rostrocaudal difference through the differential expressions of nNOS and iNOS in the neocortex and the striatum.