硝基酪氨酸与2型糖尿病冠心病的关系研究

目的观察血清硝基酪氨酸水平与2型糖尿病（T2DM）冠心病（CHD）的关系。方法应用ELISA免疫试剂盒测定109例糖尿病非冠心病患者（T2DM组）、152例糖尿病合并冠心病患者（T2DM-CHD组）和103名正常对照者（对照组）硝基酪氨酸浓度。结果（1）T2DM-CHD组血清硝基酪氨酸浓度为（78．17±10．68）nmol／L,高于T2DM组[（70．50±9．13）nmol／L]及对照组[（63．23±11．55）nmol／L],差异均有统计学意义（P均〈0．01）。（2）对所有糖尿病患者进行相关分析发现,硝基酪氨酸与总胆固醇、甘油三酯、空腹血糖、Gensini积分相关（r=0．361,P=0．009;r=0．206,P=0．001;r=0．347,P=0．026;r=0．466,P〈0．001）。Logistic回归分析发现硝基酪氨酸是2型糖尿病合并冠心病的危险因素之一（OR=1．094,95％CI：1．053-1．137;P〈0．01）。结论硝基酪氨酸在2型糖尿病及2型糖尿病合并冠心病的发生过程中起重要作用。     

早期糖尿病大鼠视网膜中神经型一氧化氮合酶的表达改变在蛋白质氧化损伤中的作用

目的:研究糖尿病是否会改变视网膜中神经型一氧化氮合酶(neuronalnitricoxidesynthase,nNOS)的表达,以及其表达的改变在蛋白质氧化损伤中的作用。方法:Sprague-Dawley(SD)大鼠,分成对照组及2组实验组,每组5只。实验组腹腔注射链佐星(streptozotocin,STZ)(65mg/kg)制备糖尿病大鼠动物模型。分别在造模成功后2及20周,研究大鼠视网膜内源性nNOS和蛋白质损伤产物3-硝基酪氨酸(3-nitrotyrosine,NT)的表达及其改变。NT用免疫组化法和计算机图像处理检测,nNOS的表达采用免疫组化和反转录聚合酶链反应(RT-PCR)方法检测。结果:对照组大鼠视网膜内无NT的免疫反应,糖尿病大鼠视网膜神经节细胞层、内核层和外核层均有NT的免疫反应,计算机图像处理显示,糖尿病20周大鼠的视网膜内NT阳性细胞数显著高于2周的糖尿病大鼠。RT-PCR结果显示,糖尿病大鼠视网膜的nNOS的mRNA表达低于对照大鼠,免疫组化结果也显示糖尿病大鼠视网膜的nNOS阳性细胞数少于对照组。结论:早期糖尿病大鼠视网膜内3-硝基酪氨酸的含量升高。早期糖尿病视网膜内,降低的nNOS的mRNA和酶的表达显示,nNOS产生的一氧化氮(nitrogenmonoxide,NO)可能是糖尿病视网膜内NT的限制性因素。这些结果同时提示,NO活性降低可能参与实验性糖尿病大鼠神经血管功能紊乱的形成     

早期糖尿病大鼠视网膜中神经型一氧化氮合酶的表达改变在蛋白质氧化损伤中的作用

目的：研究糖尿病是否会改变视网膜中神经型一氧化氮合酶(neuronal nitric oxide synthase，nNOS)的表达，以及其表达的改变在蛋白质氧化损伤中的作用。方法：Sprague—Dawley(SD)大鼠，分成对照组及2组实验组，每组5只。实验组腹腔注射链佐星(streptozotoein，STZ)(65mg／kg)制备糖尿病大鼠动物模型。分别在造模成功后2及20周，研究大鼠视网膜内源性nNOS和蛋白质损伤产物3—硝基酪氨酸(3-nitrotyrosine，NT)的表达及其改变。NT用免疫组化法和计算机图像处理检测，nNOS的表达采用免疫组化和反转录聚合酶链反应(RT—PCR)方法检测。结果：对照组大鼠视网膜内无NT的免疫反应，糖尿病大鼠视网膜神经节钿胞层、内核层和外核层均有NT的免疫反应，计算机图像处理显示，糖尿病20周大鼠的视网膜内NT阳性细胞数显著高于2周的糖尿病大鼠。RT—PCR结果显示，糖尿病大鼠视网膜的nNOS的mRNA表达低于对照大鼠，免疫组化结果也显示糖尿病大鼠视网膜的nNOS阳性细胞数少于对照组。结论：早期糖尿病大鼠视网膜内3—硝基酪氨酸的含量升高。早期糖尿病视网膜内，降低的nNOS的mRNA和酶的表达显示，nNOS产生的一氧化氮(nitrogen monoxide，NO)可能是糖尿病视网膜内NT的限制性因素。这些结果同时提示，NO活性降低可能参与实验性糖尿病大鼠神经血管功能紊乱的形成。     

黄芩苷治疗糖尿病及其并发症的研究进展

糖尿病代谢异常、胰岛素抵抗、氧化应激等会引起肾脏、视网膜及神经等微血管并发症。开展糖尿病并发症防治措施不仅是国际医学研究的热点,也是我国糖尿病领域丞待解决的难题。黄芩苷是黄芩中提取出来的类黄酮化合物,是黄芩的有效生物活性成分之一,有抗肿瘤、抗菌及抗氧化等作用。近年来发现,黄芩苷对糖尿病及并发症有治疗作用,被认为是治疗糖尿病的有效中药,亦或成为治疗糖尿病的新兴药物。本文就目前黄芩苷治疗糖尿病合并肾脏疾病、糖尿病视网膜病变和糖尿病神经病变等常见并发症的作用机制进行总结,并阐述其在治疗妊娠合并糖尿病中的潜力,为糖尿病及其并发症治疗提供依据。     

姜黄素及其衍生物对糖尿病及其并发症的作用及机制研究概况

姜黄素是姜科植物姜黄的干燥根茎中的有效成分之一。它具有抗炎、抗氧化、免疫调节、抗肿瘤、降血脂、抑制心肌重构等多种药理作用。近年来,有文章报道它对糖尿病及其导致的并发症方面有很大的疗效,未来也许能成为一种新型的治疗糖尿病的药物。论文主要介绍姜黄素及其衍生物对糖尿病及其相关并发症的作用及可能的作用机制,其中主要包括糖尿病导致的神经病变、氧化应激、心肌损伤、肾病、视网膜病变等。     

人视网膜色素上皮细胞诱导型一氧化氮合酶和活性氧在高糖状态下的表达

背景：高血糖导致的自由基损伤是糖尿病视网膜病变发病机制的中心环节。目的：观察高糖对体外培养的人视网膜色素上皮细胞的氧化损伤作用以及高糖对人视网膜色素上皮细胞诱导型一氧化氮合酶和活性氧表达的影响。方法：将培养人视网膜色素上皮细胞,分为对照组、高糖组和甘露醇组,分别用含5.5mmol/L葡萄糖,33mmol/L葡萄糖及5.5mmol/L葡萄糖和27.5mmol/L甘露醇的DMEM培养液培养。采用相差倒置显微镜观察细胞生长形态,采用免疫荧光染色研究诱导型一氧化氮合酶和3-硝基酪氨酸蛋白表达的变化,用氯甲基二氯二氢荧光素二乙酯荧光染色检测视网膜色素上皮细胞中活性氧的产生量。结果与结论：与对照组相比,应用含33mmol/L葡萄糖的DMEM培养基处理视网膜色素上皮细胞48h可见细胞胞体变薄,形态表现多样,不规则细胞增多;高糖培养的视网膜色素上皮细胞诱导型一氧化氮合酶和3-硝基酪氨酸蛋白表达增加,活性氧产生明显增多。说明高浓度葡萄糖培养可造成人视网膜色素上皮细胞氧化损伤,使细胞形态发生变化,并导致细胞中3-硝基酪氨酸产生增多。     

糖化白蛋白与动脉粥样硬化

糖化白蛋白是一种重要的糖基化产物,也是反映糖尿病血糖变化的敏感指标,与糖尿病血管并发症关系密切。现从糖化白蛋白对基质功能的影响、与特异性受体作用等方面,对其在动脉粥样硬化发生发展中的作用及机制作一综述,为临床防治糖尿病及其并发症提供新的思路。     

微小RNA在糖尿病并发症诊断治疗中的研究进展

糖尿病可引发多种并发症,大量研究表明微小RNA在糖尿病并发症中发挥着重要的作用,其表达调控与糖尿病并发症的发生、发展及治疗密切相关。该文针对几种主要的糖尿病并发症及其相关的微小RNA进行综述,以期为这些疾病的诊断与治疗提供更多理论依据。     

皮肤晚期糖基化终末产物荧光检测在糖尿病中应用研究进展

晚期糖基化终末产物(advanced glycation end products, AGEs)是指在持续高血糖状态下,蛋白质、核酸或脂类等大分子物质与还原糖发生非酶促反应形成的稳定化合物。AGEs及其受体介导的通路在糖尿病及其并发症的发生、发展中起重要作用。皮肤AGEs荧光强度可反映糖尿病患者体内AGEs蓄积程度和血糖控制情况,可评估糖尿病慢性并发症的发生风险。本文就AGEs概述、AGEs在糖尿病发病中的作用机制、皮肤AGEs荧光检测在糖尿病诊断及并发症发生风险评估中应用的研究进展作一综述。     

人视网膜色素上皮细胞诱导型一氧化氮合酶和活性氧在高糖状态下的表达

背景:高血糖导致的自由基损伤是糖尿病视网膜病变发病机制的中心环节.目的:观察高糖对体外培养的人视网膜色素上皮细胞的氧化损伤作用以及高糖对人视网膜色素上皮细胞诱导型一氧化氮合酶和活性氧表达的影响.方法:将培养人视网膜色素上皮细胞,分为对照组、高糖组和甘露醇组,分别用含5.5 mmol/L葡萄糖,33 mmol/L葡萄糖及5.5 mmol/L葡萄糖和27.5 mmol/L甘露醇的DMEM培养液培养.采用相差倒置显微镜观察细胞生长形态,采用免疫荧光染色研究诱导型一氧化氮合酶和3-硝基酪氨酸蛋白表达的变化,用氯甲基二氯二氢荧光素二乙酯荧光染色检测视网膜色素上皮细胞中活性氧的产生量.结果与结论:与对照组相比,应用含33 mmol/L葡萄糖的DMEM培养基处理视网膜色素上皮细胞48 h可见细胞胞体变薄,形态表现多样,不规则细胞增多;高糖培养的视网膜色素上皮细胞诱导型一氧化氮合酶和3-硝基酪氨酸蛋白表达增加,活性氧产生明显增多.说明高浓度葡萄糖培养可造成人视网膜色素上皮细胞氧化损伤,使细胞形态发生变化,并导致细胞中3-硝基酪氨酸产生增多.     

NT-ProBNP与脂蛋白a测定在2型糖尿病肾损伤中的应用研究

目的探讨氨基末端B型利钠肽前体(NT-ProBNP)与脂蛋白a在2型糖尿病患者中的变化。方法健康对照组62例,2型糖尿病患者129例,其中不伴糖尿病肾病64例(DM组)、伴糖尿病肾病65例(DN组)。干式免疫荧光定量法测定NTProBNP,免疫比浊法测定血清脂蛋白a与胱抑素C(Cys-C)。结果健康对照组血清NT-ProBNP与脂蛋白a水平为(58.62±24.31)pg/mL、(102.35±43.50)mg/L;DM组为(368.70±356.50)pg/mL、(192.19±184.40)mg/L;DN组为(820.66±730.85)pg/mL、(328.17±285.71)mg/L。健康对照组血清Cys-C水平为(0.52±24.31)mg/L;DM组为(0.84±0.12)mg/L;DN组为(1.97±1.15)mg/L。结论 NT-ProBNP、脂蛋白a和糖尿病及其微血管病变密切相关,可作为诊断糖尿病肾病和评估肾脏损伤程度的指标。     

Characterization of Single Thyroid Nodules by Contrast-Enhanced 3-D Ultrasound

High-resolution ultrasonography (HRUS) has potentialities in differential diagnosis between malignant and benign thyroid lesions, but interpretative pitfalls remain and accuracy is still poor. We developed an image processing technique for characterizing the intra-nodular vascularization of thyroid lesions. Twenty nodules (10 malignant) were analyzed by three-dimensional (3-D) contrast-enhanced ultrasound imaging. The 3-D volumes were preprocessed and skeletonized. Seven vascular parameters were computed on the skeletons: number of vascular trees (NT); vascular density (VD); number of branching nodes (or branching points) (NB); mean vessel radius (MR); 2-D (DM) and 3-D (SOAM) tortuosity; and inflection count metric (ICM). Results showed that the malignant nodules had higher values of NT (83.1 vs. 18.1), VD (00.4 vs. 0.01), NB (1453 vs. 552), DM (51 vs. 18), ICM (19.9 vs. 8.7) and SOAM (26 vs. 11). Quantification of nodular vascularization based on 3-D contrast-enhanced ultrasound and skeletonization could help differential diagnosis of thyroid lesions. (E-mail: filippo.molinari@polito.it)     

Effect of methamphetamine self-administration on neurotensin systems of the basal ganglia

Methamphetamine (METH) dependence causes alarming personal and social damage. Even though many of the problems associated with abuse of METH are related to its profound actions on dopamine (DA) basal ganglia systems, there currently are no approved medications to treat METH addiction. For this reason, we and others have examined the METH-induced responses of neurotensin (NT) systems in the basal ganglia. This neuropeptide is associated with inhibitory feedback pathways to nigrostriatal DA projections, and NT tissue levels are elevated in response to high doses of noncontingent METH because of its increased synthesis in the striatonigral pathway. The present study reports the contingent responses of NT in the basal ganglia to self-administration of METH (SAM). Intravenous infusions of METH linked to appropriate lever-pressing behavior by rats significantly elevated NT content in both dorsal striatum (210%) and substantia nigra (202%). In these same structures, NT levels were also elevated in yoked METH animals (160 and 146%, respectively) but not as much as in the SAM rats. These effects were blocked by a D1, but not D2, antagonist. A NT agonist administered before the day 5 of operant behavior blocked lever-pressing behavior in responding rats, but a NT antagonist had no significant effect on this behavior. These are the first reports that NT systems associated with striatonigral pathway are significantly altered during METH self-administration, and our findings suggest that activation of NT receptors during maintenance of operant responding reduces the associated lever-pressing behavior.     

The Differential Diagnostic Value of Serum NT‐proBNP in Hospitalized Patients of Heart Failure With Pneumonia

Serum N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) is considered as an effective predictor for patients with heart failure (HF), while a strong body of evidence has found its utility in inflammatory diseases. It is difficult to differentiate HF and HF coexisting with other inflammations by measuring NT‐proBNP. The aim of this study was to estimate the differential diagnostic performance of serum NT‐proBNP in hospitalized HF patients with pneumonia. A prospective study was launched. Sixty nine HF patients, 51 HF patients complicated with pneumonia, and 38 patients with pneumonia were enrolled. Serum NT‐proBNP levels were measured on Roche Elecsys. X‐ray and the European Society of Cardiology (ESC) diagnostic principles were adopted to identify patients with pneumonia and HF, respectively. The diagnostic performance of NT‐proBNP was assessed by ROC. Serum NT‐proBNP [7,039(1,008–24,672) pg/ml] in patients of HF complicated with pneumonia was significantly higher than that in those of patients with single HF [3,147(616–24,062) pg/ml] or single pneumonia [911(98–3,812) pg/ml] (P < 0.0001). No correlation was found between the level of NT‐proBNP and hospital stay. The area under ROC curve (AUC) of NT‐proBNP for distinguishing patients of HF with pneumonia was 0.8082. At the level of 4,691 pg/ml, the optimal cutoff value, 74.5% sensitivity and 81.8% specificity of NT‐proBNP were predicted. Evaluation of serum NT‐proBNP is conducive for clinicians to identify patients of HF with pneumonia, but its poor efficacy in monitoring the curative therapy in this entire cohort is not recommended.     

Elevation of Plasma Neurotensinlike Immunoreactivity after a Meal: CHARACTERIZATION OF THE ELEVATED COMPONENTS

The detection of an elevation in neurotensinlike immunoreactivity in peripheral plasma for several hours after a meal has been confirmed and shown to be primarily due to the presence of aminoterminal fragments of neurotensin (NT) rather than to NT itself. We have developed a procedure to separate and characterize these N-terminal cross-reacting substances, and to estimate the contributions of these constitutents to plasma neurotensinlike immunoreactivity. Gel chromatography of pooled plasma extracts on Sephadex G-25 followed by reverse-phase high pressure liquid chromatography indicated that peptides coeluting with NT and its N-terminal partial sequences NT(1-8) and NT(1-11) were present in plasma. Comparison of plasmas collected before and 1 h after a defined meal, in five experiments, demonstrated no change in C-terminal immunoreactivity and an 8- to 10-fold rise in N-terminal immunoreactivity. Chromatographic analysis of pooled pre- and postmeal plasma in four experiments showed that essentially all of this elevation in neurotensinlike immunoreactivity measured with an N-terminal directed antiserum was due to increases in NT(1-8) and NT(1-11), while NT itself, measured using a C-terminal directed antiserum, did not increase appreciably in peripheral plasma 1 h after the meal. Generation of tritiated substances with the same elution times as NT(1-8) and NT(1-11) did occur after incubation of [³H]NT with whole blood in vitro, providing supporting evidence that these fragments are metabolites of NT. The marked elevation in the circulating levels of these fragments reflects that an increased secretion of NT occurred in response to the test meal. The secreted NT may have acted as a hormone before it was metabolized, or it may only have had a local (paracrine) effect.     

Aurora A蛋白在神经母细胞性肿瘤中的表达与其临床特征的关系

目的 探讨Aurora A蛋白在神经母细胞性肿瘤(NT)中的表达情况与NT临床特征的关系.方法 选择2008年4月至2015年6月于华中科技大学同济医学院附属同济医院就诊的22例NT患儿为研究对象,纳入研究组(n=22).选择同期于病例收集医院就诊的10例非肿瘤患儿为对照组(n=10).采用免疫组织化学方法检测Aurora A蛋白在研究组NT患儿肿瘤组织标本和对照组患儿骨髓标本中的表达,并观察Aurora A蛋白表达水平与NT相关临床特征的关系.结果 ①研究组Aurora A蛋白表达阳性比例为68.2％,显著高于对照组(0),2组比较,差异有统计学意义(P＜0.001).②研究组中,神经母细胞瘤(NB)和节细胞NB患儿的Aurora A蛋白表达阳性比例比较,差异有统计学意义(P＜0.05),而不同性别、年龄、临床分期、是否发生骨髓转移等患者的Aurora A蛋白表达阳性比例比较,差异无统计学意义(P＞0.05).结论 Aurora A蛋白在NT中呈高表达,其相应的Aurora A激酶抑制剂可能成为治疗NT的新靶向药物.     

Neurotensin analogs [D-TYR11] and [D-PHE11]neurotensin resist degradation by brain peptidases in vitro and in vivo

The present study was designed to compare the susceptibility of neurotensin (NT), [3H]NT, [D-Tyr11]NT and [D-Phe11]NT to degradation by 1) rat brain synaptic membranes in vitro and 2) after i.c.v. administration in the rat in vivo. Degradation was assessed by purifying the peptides using reverse phase high-performance liquid chromatography and by measuring the amount of radioactive or absorbing (OD 230) material under each peptide peak. In contrast to NT, [D-Tyr11]NT and [D-Phe11]NT were resistant to degradation by brain synaptic peptidases in vitro. Furthermore, NT was rapidly metabolized in brain tissues after i.c.v. administration, whereas [D-Tyr11]NT was metabolically stable. The present data confirm the central role of NT residue Tyr11 in the mechanisms of NT inactivation by brain synaptic peptidases. They account for the higher in vivo potency of [D-Tyr11]NT as compared with its in vitro potency. Finally, they explain, at least in part, the need to administer large doses of NT in the brain in order to observe neurobehavioral and neuropharmacological effects.     

Neurohormonal regulation of ion transport in the porcine distal jejunum. Actions of neurotensin and its natural homologs

The tridecapeptide neurotensin (NT) is present at high concentrations within the mammalian gut, although its physiological function is undefined. In this study, the actions of NT and structurally related peptides neuromedin N (NM-N) and xenopsin were characterized on ion transport in the porcine distal jejunal mucosa in vitro. The serosal-side administration of these peptides elicited rapid changes in transmural potential difference and short-circuit current (Isc) which were greater in mesenteric than in antimesenteric segments. NT-induced elevations in Isc were dependent upon external permeant anions and were associated with net Cl transport in both segments. In mesenteric segments, NT and its homologs increased Isc with the order of potency: NT greater than NM-N greater than xenopsin. NT produced tachyphylaxis to its own actions and to those of NM-N; NM-N was ineffective in producing tachyphylaxis. Isc elevations produced by NT were inhibited by the neuronal conduction blocker tetrodotoxin (0.1 microM) or the Ca++-channel blocker dl-verapamil (100 microM) and reduced in Ca++-free media. Antagonists to the enteric transmitters acetylcholine, ATP, 5-hydroxytryptamine, substance P and histamine did not alter Isc responses of mesenteric segments to NT. Serosal administration of vasoactive intestinal peptide (10 nM) did not resemble the effects of NT. The magnitude of Isc responses to these agonists was smaller in antimesenteric segments. These results indicate that NT-related peptides present in mucosal endocrine cells or nerves of the porcine jejunum may modulate Cl transport through mechanisms that involve the Ca++-dependent release of unknown enteric neurotransmitters. Moreover, there appear to exist within the distal jejunum circumferential differences in mucosal responses to NT and other neurohumoral factors.     

Human autologous mixed lymphocyte reactivity is primarily specific for xenoprotein determinants adsorbed to antigen-presenting cells during rosette formation with sheep erythrocytes

We present evidence that most T cells proliferating in response to autologous sheep erythrocyte (SRBC)-separated non-T cells (NT) cells are not specific for autoantigens but for antigens derived from xenogeneic sources. The conclusion was based on the following three observations. First, we found that NT cells isolated in the absence of xenoproteins by means of density gradient centrifugation on Percoll only weakly stimulated autologous T cells. Because this weak proliferation could not be expanded in restimulation experiments, its significance as an immune recognitive event remains questionable. NT cells isolated by the above method in the absence of xenogeneic determinants readily acquired stimulatory capacity after brief exposure to either SRBC or fetal calf serum. Second, restimulation of T memory cells generated in 1 degree autologous mixed lymphocyte reaction (AMLR) against SRBC-separated autologous NT cells was exclusively seen when NT cells exposed to or separated with xenoproteins were used for restimulation. Third, T memory cells generated against SRBC-separated autologous NT cells were specifically restimulated by autologous Percoll-separated NT cells that had been pulsed with a variety of xenogeneic mammalian sera. These xenogeneic determinants were preferentially recognized in context with autologous HLA-DR+ cells. From these findings and from our previous results that indicated an absolute requirement of HLA-DR+-adherent NT cells (8), we conclude that human AMLR primarily does not represent an autoantigen but a xenoantigen response that is genetically restricted by the HLA-DR type of the antigen-presenting cell.     

Antibodies against mumps virus component proteins

The neutralization (NT) test is regarded as the most reliable method for detection of protective antibodies, but is labor-intensive and time consuming. Enzyme-linked immunosorbent assay (EIA) is frequently used in sero-epidemiological studies because of its simplicity and ease of use. In this study, immunofluorescent (IF) antibodies against nucleocapsid (N), fusion (F), and hemagglutinin-neuraminidase (HN) proteins were investigated in comparison with NT and EIA antibodies. The antibody against N protein was dominant in serum samples obtained from patients with a previous history of mumps infection. Titers of antibodies against F and HN proteins were very low. Many serum samples were positive for EIA but negative for NT, and no significant correlation was noted between NT and EIA antibodies. Among the three component proteins, correlation of EIA and IF antibodies with N protein was relatively good. After vaccination with mumps vaccine, EIA positivity was closely related to the IF antibodies against N protein, and after vaccination NT-positive sera became positive for IF antibodies against F and HN proteins. IF antibodies against F and HN proteins were considered to have a strong association with NT antibodies, and those against N protein were considered to have a strong association with EIA antibodies.