基于CNV区域网络识别神经胶质瘤的重要功能区域

目的：基于基因拷贝数变异（CNV）区域网络识别神经胶质瘤的重要功能区域。方法：运用独特的计算样本的共相关性值的方法,使CNV数据与基因数据产生联系;基于蛋白质互作关系,在CNV区域与基因之间搭建桥梁,构建CNV区域网络;分析网络拓扑性质,识别出神经胶质瘤的重要功能CNV区域。结果：本文共识别出了11个与神经胶质瘤相关的候选重要功能CNV区域,通过功能注释和通路分析,确认了识别到的区域与神经胶质瘤有重要联系。结论：通过基因与表型之间的联系,利用已知表型基因在同源、功能、互作、结构域上的特征将CNV区域与基因联系起来,通过基因的功能可以了解到CNV区域的功能,对于疾病的预测和诊断有重要的意义。     

窄谱中波紫外线联合复方甘草酸苷片治疗手部湿疹的疗效观察及对外周血IFN-γ、IL-4水平的影响

目的：探讨窄谱中波紫外线（NB—UVB）联合复方甘草酸苷片治疗手部湿疹的的疗效及其对外周血疗效观察IFN-γ、IL-4水平的影响。方法：选取手部湿疹患者160例,随机分为观察组与对照组,每组各80例。对照组给予尿素乳膏涂于患处,观察组采用NB-UVB皮损局部照射联合复方甘草酸苷片治疗,均连续治疗4周。治疗前后观察临床表现、EASI评分、血清IFN-γ、IL-4,记录不良反应。结果：治疗后,观察组与对照组总有效率分别为90．00％、72．50％（P〈0．05）,EASI评分均不同程度的降低（P〈0．01或P〈0．05）,且观察组EAsI评分低于对照组（P〈0．05）;观察组血清WN-γ水平降低,几4升高（P〈0．05）,且与对照组相应指标比较,差异具有统计学意义（P〈0．05）。两组均未见明显的不良反应。结论：窄谱中波紫外线联合复方甘草酸苷片治疗手部湿疹具有较高的临床总有效率,改善了手部湿疹的皮损状况,调节了Th1／Th2细胞因子趋于平衡,且具有较高的安全性,对手部湿疹的临床治疗具有一定的指导意义。     

嵌段共聚物聚乙二醇-聚苹果酸苄基酯载药胶束的制备及性质研究

目的：为构建聚合物胶束药物运载体系,制备嵌段共聚物聚乙二醇-聚苹果酸苄基酯载药胶束并测定其性质。方法：以L-天冬氨酸为原料,重氮化、环化后经开环聚合得到聚苹果酸苄基酯。氨基聚乙二醇通过酰胺键连接到β-聚苹果酸苄基酯上形成两亲性嵌段共聚物,喜树碱做药物模型制备载药胶束。动态光散射法测定胶束粒径、评价胶束稳定性,高效液相法测定喜树碱载药率和包封率,芘荧光法与动态光散射法测定临界胶束浓度。结果：喜树碱包封率72%,载药率6%,临界胶束浓度为40μg.mL-1。随着聚苹果酸苄基酯分子量减小,胶束稳定性增强。结论：聚乙二醇-聚苹果酸苄基酯在疏水链/亲水链分子量比值为2-4时在水中可自组装形成纳米胶束,可作为性能优良的聚合物药物载体。     

适当浓度的过氧化氢诱导人支气管上皮细胞发生钙振荡

包括过氧化氢（Hzoz）在内的活性氧通过引起细胞内钙的变化而造成细胞损伤。然而,不同浓度的H202可以导致细胞内不同的钙变化,并激活不同的信号通路。细胞内钙振荡是其中的一种钙信号变化形式,钙振荡可以调控转录因子NF—KB的活性。该研究探讨可以诱导支气管上皮细胞内钙振苏发生的H2o2浓度。体外培养人支气管上皮细胞,采取钙离子荧光探针Fura_2标记细胞。并使用离子成像系统,观测不同浓度的H：0：（0～1000μmol／L）作用下细胞内钙浓度的变化。结果发现,低于50μmol／L的H202仅仅引起“钙火花”;50～500μmol／L的H202导致细胞内钙振荡的发生;而1000μmol／L的H202引起细胞内持续的高钙;同时也证实150μmol／L的H202诱发明显的钙振荡,而钙振荡随后引起了NF—KB活性的升高。该研究提示,适当浓度的H：0：可以诱发支气管上皮细胞内钙振荡的发生,推测可能是活性氧导致慢性气道炎症损伤的一个机制。     

Crystal structure of the S187F variant of human liver alanine: Aminotransferase associated with primary hyperoxaluria type I and its functional implications

The substitution of Ser187, a residue located far from the active site of human liver peroxisomal alanine:glyoxylate aminotransferase (AGT), by Phe gives rise to a variant associated with primary hyperoxaluria type I. Unexpectedly, previous studies revealed that the recombinant form of S187F exhibits a remarkable loss of catalytic activity, an increased pyridoxal 5′‐phosphate (PLP) binding affinity and a different coenzyme binding mode compared with normal AGT. To shed light on the structural elements responsible for these defects, we solved the crystal structure of the variant to a resolution of 2.9 Å. Although the overall conformation of the variant is similar to that of normal AGT, we noticed: (i) a displacement of the PLP‐binding Lys209 and Val185, located on the re and si side of PLP, respectively, and (ii) slight conformational changes of other active site residues, in particular Trp108, the base stacking residue with the pyridine cofactor moiety. This active site perturbation results in a mispositioning of the AGT‐pyridoxamine 5′‐phosphate (PMP) complex and of the external aldimine, as predicted by molecular modeling studies. Taken together, both predicted and observed movements caused by the S187F mutation are consistent with the following functional properties of the variant: (i) a 300‐ to 500‐fold decrease in both the rate constant of L‐alanine half‐transamination and the k_cat of the overall transamination, (ii) a different PMP binding mode and affinity, and (iii) a different microenvironment of the external aldimine. Proposals for the treatment of patients bearing S187F mutation are discussed on the basis of these results. Proteins 2013; 81:1457–1465. © 2013 Wiley Periodicals, Inc.     

A liquid chromatography–tandem mass spectrometry assay for d-Ala-d-Lac: A key intermediate for vancomycin resistance in vancomycin-resistant enterococci

Vancomycin exerts its antibacterial activity by binding to d-Ala-d-Ala in bacterial cell wall precursors. Vancomycin resistance in vancomycin-resistant enterococci (VRE) is due to an alternative cell wall biosynthesis pathway in which d-Ala-d-Ala is replaced, most commonly by d-Ala-d-Lac. In this study, we extend our recently developed Marfey’s derivatization-based liquid chromatography–tandem mass spectrometry (LC–MS/MS) assay for l-Ala, d-Ala, and d-Ala-d-Ala to d-Ala-d-Lac and apply it to the quantitation of these metabolites in VRE. The first step in this effort was the development of an effective washing method for removing medium components from VRE cells. Mar-d-Ala-d-Lac was well resolved chromatographically from Mar-d-Ala-d-Ala, a prerequisite for MS/MS quantitation of d-Ala-d-Ala and d-Ala-d-Lac. Mar-d-Ala-d-Lac gave similar detection parameters, sensitivity, and linearity as Mar-d-Ala-d-Ala. l-Ala, d-Ala, d-Ala-d-Ala, and d-Ala-d-Lac levels in VRE were then determined in the presence of variable vancomycin levels. Exposure to vancomycin resulted in a dramatic reduction of d-Ala-d-Ala, with a response midpoint at approximately 0.06 μg/ml vancomycin and with a broad response profile up to 128 μg/ml vancomycin. In contrast, d-Ala-d-Lac was present in the absence of vancomycin, with its level constant up to 128 μg/ml vancomycin. This method will be useful for the discovery, characterization, and refinement of new agents targeting vancomycin resistance in VRE.     

In vitro characterization of the inhibitor resistance of glutamate-1-semialdehyde aminotransferase from the cyanobacterium Synechococcus PCC630l GR6

Glutamate-l-semialdehyde (GSA) aminotransferase catalyses the final step in the C5 pathway converting glutamate to the tetrapyrrole precursor δ-aminolaevulinic acid. This enzyme is sensitive to gabaculine (2,3-dihydro-3-amino benzoic acid) and to 4-amino-5-fluoropentanoic acid (AFPA), which are irreversible, mechanism-based inhibitors of pyridoxal phosphatedependent enzymes. Spontaneous mutants of Synechococcus PCC6301 resistant to these inhibitors contain altered enzyme that displays corresponding resistance to high concentrations of the inhibitor. The enzyme from strain GR6, resistant to both inhibitors, contains a three-amino-acid deletion at positions 5–7 and a Met²⁴⁸ → Ile substitution. The enzyme from strain K40 resistant to AFPA but not to gabaculine, contains a Ser¹⁶³ → Thr substitution. GSA aminotransferases containing either the deletion or the substitution that are characteristic of the GR6 mutant were produced in Escherichia coli using the expression vector pMalc2. These engineered mutant enzymes were characterized in terms of their catalytic parameters and sensitivities to gabaculine and AFPA. Furthermore, maltose binding protein/aminotransferase fusion proteins were characterized spectrophotometrically to monitor the interaction of bound cofactor with diamino- and dioxocompounds related to the substrate and both inhibitors. Results were compared with those for similarly produced recombinant wild-type, K40 and GR6 GSA aminotransferases. The engineered products with either the N-terminal deletion or the Met²⁴⁸ → Ile substitution displayed catalytic efficiencies that were intermediate between the wild-type and GR6 or K40 enzymes. However, with respect to their absorption spectra, sensitivity to inhibitors and the reactivity of bound cofactor, they were essentially wild-type. These in vitro studies demonstrate that both changes in enzyme structure are necessary to obtain the distinctive properties of the GR6 aminotransferase, including resistance to high concentrations of gabaculine and AFPA.     

胃肝样腺癌的临床病理特征

目的探讨胃肝样腺癌（hepatoid adenocarcinoma of the stomach,HAS）的临床病理学特点、发生机制和免疫组化特征,以提高诊断水平。方法收集并分析5例胃肝样腺癌的临床特征和病理资料,采用HE染色、免疫组化方法,并复习文献。结果组织学胃肝样腺癌具有管状腺癌、粘液性癌和肝样分化腺癌的移行过渡,肿瘤细胞呈小梁状、巢团状,间质为丰富的血窦。免疫表型胃肝样腺癌AAT（5／5）、ACT（5／5）、CEA（5／5）、AFP（4／5）均为阳性,Heppar1灶性阳性（2／5）。结论胃肝样腺癌是一种少见的高度恶性、侵袭性强的特殊类型胃癌,组织学呈肝细胞样腺癌,免疫表型AFP、AAT和ACT阳性有助诊断。     

The Baseline Cosinus Function: A Periodic Regression Model for Biological Rhythms

Abstract

Both tryptophan oxygenase and tyrosine aminotransferase of rat liver show diurnal variations in the inducibility by quinolinic acid. The maxima of effectiveness of quinolinic acid precede the maxima of normal enzyme activity. In the case of tyrosine aminotransferase, the induction kinetics and the dose response curve were also greatly depending on the time of day. No rhythmicity could be detected in the activities of 3‐hydroxyanthranilate oxygenase and ornithine aminotransferase.     

On the chronobiology of Tetrahymena. II. Further evidence for the persistence of ultradian rhythmicity in the absence of protein synthesis and cell growth∗∗

Abstract

In Tetrahymena thermophila, the ultradian rhythm of tyrosine aminotransferase activity was investigated under free‐running conditions. The rhythm persisted in the presence of 1 mM emetine, although the drug efficiently inhibited both protein synthesis and cell division. Also 250 mM hydroxyurea, which suppressed cell growth to a high degree, did not prevent the rhythm. These data support the concept of an ultradian oscillator working independently of translation and being not a consequence of the “cell cycle”;, although under normal physiological conditions the rhythm of tyrosine aminotransferase is accompanied by and equiperiodic with the rhythm of cell division, both in the ultradian and circadian growth modes.