某些内科系统疾病患者血浆游离氨基酸的变化及意义

为了解某些内科系统疾病的血氨基酸代谢特点。测定１７０例９种内科系统急慢性疾病患者血浆游离氨基酸浓度,并分别与５８例健康人血浆氨基酸浓度作对比分析。９种疾病的血浆胱氨基酸浓度不同程度升高,以尿毒症病人最为显著,炎症性病人血浆苯丙、蛋、赖氨酸和苯丙／酪比值显著升高,丙、组、精、脯氨酸和支／芳比值显著降低;糖尿病和甲亢病人血浆总游离氨基酸、谷、丙、酪、赖和支链氨酸显著升高;糠尿病病人支／芳比值显著升高,表明不同疾病的血氨基酸浓度有特征性变化,炎症是导致血氨基酸代谢紊乱的重要因素     

肝病要素制剂治疗急慢性肝损伤时血清氨基酸和蛋白质的变化

目的 :观察含高支链氨基酸的肝病要素制剂对急慢性肝损伤时血清氨基酸和蛋白质的变化。方法 :患急慢性肝损伤的住院病人 1 0 0例 ,男 86名 ,女 1 4名 ,平均年龄为 4 2 .4± 1 1 .8岁 ,随机分为肝病要素制剂治疗组和安慰剂对照组。口服肝病要素或安慰剂。检查肝肾功能、血清支芳氨基酸 ,观察临床症状。结果 :肝病要素制剂治疗改善临床症状和血液常规生化检验无明显影响 ;有改善和保护肝功能的作用 ,增加血清BCAA/AAA比值 ;增高血清总蛋白、白蛋白、前白蛋白。结论 :肝病要素制剂对急、慢肝功能损害有治疗作用 ,研究结果为其临床应用提供依据。     

各型肝病患者红细胞内氨基酸检测的临床研究

本文对３０例正常人和１０８例各型肝病患者红细胞内氨基酸进行检测,结果显示,各型肝炎与正常人比较红细胞内氨基酸均表现不同程度的增高和降低。如正常人红细胞内１７种氨基酸的总量为３５５４．４７μｍｏｌ／Ｌ,支／芳比值３．０６±０．４０;急性肝炎总量３４２３．２５μｍｏｌ／Ｌ,支／芳比值２．４８±０．３０;慢性肝炎（轻度）总量３３２９．３３μｍｏｌ／Ｌ,支／芳比值２．３９±０．２２;慢性肝炎（中度）总量３２１９．３２μｍｏｌ／Ｌ,支／芳比值１．８３±０．４０;肝硬化总量３７６２．３３μｍｏｌ／Ｌ,支／芳比值１．３６±０．４１。     

不同肝脏疾病患者血浆游离氨基酸水平改变的模式

采用DNS -Cl荧光标记氨基酸 ,聚酰胺薄膜层析 ,分析了慢性血吸虫病肝肿大、晚期血吸虫病肝肿大 ,慢活肝 ,慢迁肝以及肝硬化等五种不同肝损伤患者血浆游离氨基酸水平 ,结果发现它们血浆游离氨基酸改变 ,均有一定的特异的模式     

烧伤患者血浆和红细胞游离氨基酸变化及输注氨基酸对其变化的影响

动态测定烧伤患者血浆及红细胞内游离氨基酸的含量 ,探讨输入外源性氨基酸后对血及红细胞内游离氨基酸的影响。以日立 835— 5 0型氨基酸自动分析仪测定烧伤患者血浆及红细胞内游离氨基酸含量。结果发现烧伤患者血浆总游离氨基酸浓度从伤后到 2 1天均显著降低 (P <0 .0 5～ 0 .0 1) ;赖、苯丙和苯丙 酪氨酸比值显著升高 (P <0 .0 5～ 0 .0 1) ;色、组、精、丙、甘、苏、脯和丝氨酸比值显著降低 (P <0 .0 5～ 0 .0 1) ;缬、亮、异亮、酪、胱和支链氨基酸伤后早期降低。烧伤患者红细胞内总游离氨基酸含量不同程度降低 ,其中 1、3、7天降低显著 (P <0 .0 5～ 0 .0 1) ;红细胞内苯丙和苯丙 酪氨酸比值未见显著性升高 ;色、蛋、精、脯氨酸含量很低或基本未测出。输注复合氨基酸注射液后未能显著改善患者血及红细胞内游离氨基酸含量。结果提示烧伤患者红细胞内游离氨基酸含量的变化趋势与血浆游离氨基酸变化趋势基本一致 ;烧伤后红细胞内苯丙氨酸及苯丙 酪氨酸比值有别于血浆变化。本研究条件下补充外源性氨基酸未能显著改变烧伤患者血浆及红细胞内游离氨基酸的含量     

血浆游离氨基酸与支/芳比值DNS荧光法测定

<正> 近年来,随着各种氨基酸代谢疾病早期诊断的需要,血浆支链与芳香族氨基酸浓度比值(BCAA/AAA)作为慢性肝病诊断指标的提出,以及氨酸输液疗法的开展,临床上迫切需要对血浆及其它体液的游离氨基酸进行定量分析。先进的自动分析仪器价格昂贵,经典的纸层析—茆三酮法又难以选到要求,因而目前在普通医院中尚难开展此项定量工作。     

120例肝源性糖尿病患者临床特点分析

目的:探讨肝源性糖尿病的临床特点及其治疗,以提高对该病的诊疗水平.方法:120例肝源性糖尿病(HD)患者,其中46例行OGTT试验,检测了血糖、胰岛素、C肽、胰岛素敏感指数(ISI),HOMA-IR及空腹血糖、空腹胰岛素(FPG/FINS)评估胰岛素抵抗,并与50例2型糖尿病(T2DM)患者进行对比分析.结果:21例(17.5％)HD患者有三多一少糖尿病典型症状.OGTT结果显示HD组空腹血糖低于T2DM组(P＜0.05);胰岛素+C肽释放试验显示T2DM组和HD组胰岛素分泌呈高峰延迟型,HD患者各时段胰岛素及C肽水平高于T2DM患者(P＜0.05,P＜0.01).HD组的FPG/FINS及HOMA-IR低于HD组,ISI高于HD组,差异均有统计学意义(P＜0.05).经治疗后血糖大部分控制在正常或接近正常水平,9例病例均死于肝病并发症.结论:胰岛素抵抗可能是肝源性糖尿病重要的发病机制.肝源性糖尿病以餐后高血糖为特征,临床症状不典型,短期不良预后主要与原发慢性肝病有关.     

1H-MRS评估慢性肝病脑部代谢异常与肝硬化的相关性

目的:利用~1H-MRS研究慢性肝病脑部代谢改变,并探讨~1H-MRS评估慢性肝病脑部代谢异常与肝硬化Child-Pugh分级的相关性。方法:选取经临床确诊为慢性肝炎肝硬化患者42例(child A 19例,child B14例,child C 9例)及健康志愿者15例(对照组),行磁共振平扫及磁共振单体素~1H-MRS检查,计算相关代谢物N-乙酰天门冬氨酸(NAA)、谷氨酰胺复合物(Glx)、胆碱(Cho)、肌醇(mI)和肌酸(Cr)的峰下面积及前四项指标与Cr的比值(NAA/Cr、Glx/Cr、Cho/Cr、mI/Cr),并进行统计学分析,同时对相关代谢物的变化与肝硬化Child-Pugh分级及肝硬化Child-Pugh分级与肝性脑病的关系进行相关性分析。结果:~1HMRS分析显示与正常对照组相比,慢性肝炎肝硬化组Glx/Cr值升高,Cho/Cr与mI/Cr值降低,且差异均有统计学意义(P0.05);不同程度肝硬化病例组对比显示,Glx/Cr值均随着肝硬化程度加重而增大,且Glx/Cr值的差异在child A、child B、child C组中均有统计学意义(P0.05);肝性脑病(HE)组与非肝性脑病组脑代谢物峰下面积比值Glx/Cr、Cho/Cr、mI/Cr比较,差异有统计学意义(P0.05);Child-Pugh分级与Glx/Cr呈正相关,与Cho/Cr、mI/Cr呈负相关;随着肝硬化程度加重,肝性脑病出现概率越高,差异有统计学意义(P0.05)。结论:~1H-MRS作为一种无创性的评价手段,能够反映慢性肝硬化及肝性脑病患者存在脑代谢物浓度异常改变,可作为早期诊断肝硬化、肝性脑病及评价肝硬化、肝性脑病严重程度的一项指标,在一定程度上评估肝性脑病与肝硬化分级具有相关性。     

急性肝损伤大鼠模型的血浆氨基酸代谢变化模式

以Ｄ－氨基半乳糖（Ｄ－Ｇａｌａｃｔｏｓａｍｉｎｅ,Ｄ－ＧａｌＮ）造成急性肝损伤（急性肝炎、急性肝坏死）大鼠模型后、对照观察了急性肝损伤大鼠血浆氨基酸的变化,建立了大鼠急性肝损伤时血浆氨基酸的变化模式并对其发生机理进行了探讨。大鼠血浆氨基酸的测定采用聚酰薄层荧光分析技术,其测定结果是：急性肝炎组,酪氨酸（Ｔｙｒ）、天冬氨酸（Ａｓｐ）、谷氨酰胺（Ｇｌｎ）和鸟氨酸（Ｏｒｎ）升高,精氨酸（Ａｒｇ）下降,其余氨基酸无显著变化。急性肝坏死组,除Ａｒｇ显著下降外,其余所有氨基酸都显著升高,而两组支链氨基酸（ＢＣＡＡ）／芳香族氨基酸（ＡＡＡ）克分子比值均显著下降。     

2型糖尿病患者血浆chemerin水平与其冠脉病变程度的相关性分析

目的:探讨2型糖尿病患者血浆趋化素(chemerin)水平与冠脉病变程度的关系。方法:选取2011年1月~2012年2月我院收治的2型糖尿病(T2DM)患者92例,均行冠状动脉造影检查。按冠状动脉造影结果分为单纯2型糖尿病无冠状动脉病变组26例(DM0);合并单支冠状动脉病变组32例(DM1);合并双支以上病变组34例(DM2)。另选取正常健康行冠脉造影检查者25例作为正常对照组(NC)。采用酶联免疫吸附法检测各组入选者血浆chemerin水平,并分析其与冠脉病变程度的相关性。结果:T2DM及T2DM合并冠状动脉病变患者血浆chemerin水平与NC组对比均明显升高,并且与冠状动脉病变严重程度呈正相关(P0.05)。各组血浆Chemerin水平与BMI、HOMA-IR、TC、和APOB各指标间呈显著正相关(r分别为0.781、0.723、0.415、0.694,P均0.01)。结论:2型糖尿病患者冠状动脉病变的发生发展可能与血浆chemerin升高有关。     

肝硬化与肝癌患者血浆游离氨基酸水平分析

采用高效液相色谱法分析了２５例肝硬化和１５例肝癌患者空腹血浆游离氨基酸水平的变化。结果表明,二者支链氨基酸（ＢＣＡＡ）如Ｖａｌ、Ｉｌｅ呈下降趋势,而芳香族氨基酸（ＡＡＡ）如Ｔｙｒ、Ｐｈｅ则呈上升趋势,ＢＣＡＡ／ＡＡＡ分子比值下降。丙氨酸（Ａｌａ）、蛋氨酸（Ｍｅｔ）、谷氨酰胺（Ｇｌｎ）及天门冬氨酸（Ａｓｐ）明显上升。其变化趋势二者存在差别。     

Plasma amino acid imbalance in alcoholic liver cirrhosis

Plasma amino acid concentrations and plasma glucagon and serum insulin levels were studied in male patients with compensated alcoholic and nonalcoholic liver cirrhosis. Age, nutritional status, and liver function tests were similar in both groups; none of the patients presented hepatic encephalopathy. Plasma valine and leucine concentrations were lower, and tyrosine, higher in alcoholic than nonalcoholic liver cirrhosis. As a result, the molar ratios of branched-chain amino acids (BCAA) to aromatic amino acids (AAA) were reduced markedly in this group. Although correlation coefficients comparing BCAA/AAA ratios and KICG in alcoholic and nonalcoholic liver cirrhosis were similar, a steeper regression line was observed in alcoholics. Plasma glucagon and proline levels were significantly higher in alcoholic than nonalcoholic liver cirrhosis, the former correlated with AAA concentrations only in alcoholic liver cirrhosis, but not with BCAA levels. These results indicated that alcoholic liver cirrhosis presented a more deranged plasma amino acid pattern than nonalcoholic, and the amino acid imbalances, except for depressed BCAA and elevated proline, were derived, in part, from the hyperglucagonemia.     

Cloning and expression of a novel variant of human interferon-gamma cDNA

A cDNA library was prepared from the poly(A) mRNA isolated from human peripheral blood lymphocytes which were induced by combined treatment with phytohemagglutinin and a phorbol ester. Recombinant plasmids containing human interferon-gamma (HuIFN-gamma) cDNAs were identified by the oligonucleotide-hybridization method. Nucleotide sequence analysis showed that the nucleotide and amino-acid sequences of HuIFN-gamma cDNA in plasmid pIFN gamma-G4 differed from the published data at amino acid position 9 (CAA for glutamine versus AAA for lysine). The cDNA in plasmid pIFN gamma-G4 was expressed under control of the simian virus 40 early promoter in monkey COS cells and a biologically active HuIFN-gamma was secreted from the cells. The cDNA was also inserted into an expression vector carrying an E. coli tryptophan promoter and was expressed in E. coli. The results suggest that the conversion from lysine to glutamine at amino acid position 9 might not affect the specific activity of HuIFN-gamma.     

Application of cross-linked beta-cyclodextrin polymer for adsorption of aromatic amino acids

Beta-cyclodextrin (beta-CyD) was cross-linked by hexamethylene diisocyanate and the polymer was investigated for adsorption of aromatic amino acids (AAA) from phosphate buffer. High adsorption rates were observed at the beginning and the adsorption equilibrium was then gradually achieved in about 45 min. The adsorption of AAA decreased with the increase of initial concentration and also temperature. Under the same conditions, the adsorption efficiencies of AAA were in the order of L-tryptophan (L-Trp) > L-phenylalanine (L-Phe) > L-tyrosine (L-Tyr). Much higher adsorption values, up to 52.4 and 43.0 mg/g for L-Trp and L-Phe, respectively, at 50 mmol/L and 3.2 mg/g for L-Tyr at 2 mmol/L, were obtained with the beta-CyD polymer at 37 degrees C. It was shown that the adsorption of AAA on the beta-CyD polymer was consistent with the Freundlich isotherm equation. The adsorption of mixed aromatic amino acids and branched-chain amino acids (BCAA) showed that AAA were preferentially adsorbed with adsorption efficiencies 10-24%, while those of BCAA were lower than 2%. It seems that the structure and hydrophobicity of amino acid molecules are responsible for the difference in adsorption, by influencing the strength of interactions between amino acid molecule and the polymer.     

Alanine Scanning of Cucumber Mosaic Virus (CMV) 2B Protein Identifies Different Positions for Cell-To-Cell Movement and Gene Silencing Suppressor Activity

The multifunctional 2b protein of CMV has a role in the long distance and local movement of the virus, in symptom formation, in evasion of defense mediated by salicylic acid as well as in suppression of RNA silencing. The role of conserved amino acid sequence domains were analyzed previously in the protein function, but comprehensive analysis of this protein was not carried out until recently. We have analyzed all over the 2b protein by alanine scanning mutagenesis changing three consecutive amino acids (aa) to alanine. We have identified eight aa triplets as key determinants of the 2b protein function in virus infection. Four of them (KKQ/22-24/AAA, QNR/31-33/AAA, RER/34-36/AAA, SPS/40-42/AAA) overlap with previously determined regions indispensable in gene silencing suppressor function. We have identified two additional triplets necessary for the suppressor function of the 2b protein (LPF/55-57/AAA, NVE/10-12/AAA), and two other positions were required for cell-to-cell movement of the virus (MEL/1-3/AAA, RHV/70-72/AAA), which are not essential for suppressor activity.     

Plasma amino acids in four models of experimental liver injury in rats

Summary We studied the plasma amino acid profiles in four models of hepatic injury in rats. In partially hepatectomized rats (65% of liver was removed) we observed significant increase of aromatic amino acids (AAA; i.e. tyrosine and phenylalanine), taurine, aspartate, threonine, serine, asparagine, methionine, ornithine and histidine. Branched-chain amino acids (BCAA; i.e. valine, leucine and isoleucine) concentrations were unchanged. In ischemic and carbon tetrachloride acute liver damage we observed extreme elevation of most of amino acids (BCAA included) and very low concentration of arginine. In carbon tetrachloride induced liver cirrhosis we observed increased levels of AAA, aspartate, asparagine, methionine, ornithine and histidine and decrease of BCAA, threonine and cystine. BCAA/AAA ratio decreased significantly in partially hepatectomized and cirrhotic rats and was unchanged in ischemic and acute carbon tetrachloride liver damage. We conclude that a high increase of most of amino acids is characteristic of fulminant hepatic necrosis; decreased BCAA/AAA ratio is characteristic of liver cirrhosis; and decrease of BCAA/AAA ratio may not be used as an indicator of the severity of hepatic parenchymal damage.Abbreviations BCAA branched-chain amino acids (i.e. valine, leucine and isoleucine) - AAA aromatic amino acids (i.e. tyrosine and phenylalanine)     

MicroRNA-199a-5p aggravates angiotensin II–induced vascular smooth muscle cell senescence by targeting Sirtuin-1 in abdominal aortic aneurysm

Vascular smooth muscle cells (VSMCs) senescence contributes to abdominal aortic aneurysm (AAA) formation although the underlying mechanisms remain unclear. This study aimed to investigate the role of miR-199a-5p in regulating VSMC senescence in AAA. VSMC senescence was determined by a senescence-associated β-galactosidase (SA-β-gal) assay. RT-PCR and Western blotting were performed to measure miRNA and protein level, respectively. The generation of reactive oxygen species (ROS) was evaluated by H2DCFDA staining. Dual-luciferase reporter assay was used to validate the target gene of miR-199a-5p. VSMCs exhibited increased senescence in AAA tissue relative to healthy aortic tissue from control donors. Compared with VSMCs isolated from control donors (control-VSMCs), those derived from patients with AAA (AAA-VSMCs) exhibited increased cellular senescence and ROS production. Angiotensin II (Ang II) induced VSMC senescence by promoting ROS generation. The level of miR-199a-5p expression was upregulated in the plasma from AAA patients and Ang II–treated VSMCs. Mechanistically, Ang II treatment significantly elevated miR-199a-5p level, thereby stimulating ROS generation by repressing Sirt1 and consequent VSMC senescence. Nevertheless, Ang II–induced VSMC senescence was partially attenuated by a miR-199a-5p inhibitor or Sirt1 activator. Our study revealed that miR-199a-5p aggravates Ang II–induced VSMC senescence by targeting Sirt1 and that miR-199a-5p is a potential therapeutic target for AAA.     

Effects of Insulin on Free Amino Acids in Plasma and the Role of the Amino Acid Metabolism in the Etiology of Diabetic Microangiopathy

To investigate if alterations of the amino acid metabolism may play a more important role in the etiology of diabetic microangiopathy than hitherto recognized, free amino acids in plasma were measured by means of high-performance liquid chromatography (HPLC) in healthy individuals (REF) and patients with insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM). Isoleucine and leucine in IDDM were within normal limits, whereas they were significantly higher in NIDDM (P < 0.01 and P < 0.001, respectively). This was not due to age differences. In order to evaluate the impact of insulin on amino acid metabolism, amino acids were also measured in pregnant women (PREG) undergoing glucose tolerance tests as a screening for pregnancy diabetes and in patients with polycystic ovary syndrome (PCO) undergoing euglycemic insulin clamp tests. Insulin considerably reduced the amino acid concentration. Isoleucine and leucine were particularly depressed. On the whole there was strong covariance between the three branched-chain amino acids, isoleucine, leucine, and valine (P < 0.0001). There was no covariance between amino acid and glucose or HbAlc concentrations, A protein meal strongly stimulated insulin production (+55 mIU/liter), whereas a galactose meal revealed only a minor increase in insulin response (+ 12 mIU/liter) in contrast to a tolerance test with the same amount of glucose (+ 67 mIU/liter). It is concluded that disturbed amino acid metabolism may be a more important causative factor in the etiology of diabetic microangiopathy than hitherto recognized and, in addition, that this may affect the therapeutic approach in both IDDM and NIDDM patients.