Increasing Carbapenem-Resistant Gram-Negative Bacilli and Decreasing Metallo-β-Lactamase Producers over Eight Years from Korea

The trends and types of carbapenemase-producing Gram-negative bacilli were analyzed from clinical specimens collected between 2005 and 2012 at a Korean teaching hospital. The proportions of carbapenem-resistant Acinetobacter spp. increased markedly to 66%. Metallo-β-lactamase producers significantly decreased and the majority shifted from the bla_VIM-2 type to the bla_IMP-1 type.     

β-淀粉样多肽1-42(Aβ42)多克隆抗体的制备及其鉴定

目的：β—淀粉样多肽1—42(Amyloid β1-42，简称Aβ42)是存在于阿尔茨海默病(Alzheimer’s Disease，AD)患者脑组织中的特异病理改变之物，同时它在AD患者的脑积液及血浆中有所改变。我们制备Aβ42多克隆抗体及其建立测定方法，是希望找到—个特异性鉴定AD的生物指标。方法：将Aβ42多肽与匙孔虫戚血蓝蛋白(KLH)偶联，免疫新西兰白兔从而产生抗—Aβ啦多克隆抗体。此特异性抗体可用于ELISA、Western印迹法和免疫组织化学的方法中，并可测定AD脑组织中的特异性淀粉样沉淀物。结果：通过免疫组织化学法鉴定此抗—Aβ42多克隆抗体，结果显示在AD患者的脑组织淀粉样沉淀物中呈阳性。同时应用Western印迹法对Aβ42抗体进行了鉴定，结果显示Aβ42多肽的分子量与Aβ42多肽标准的4．5kDa分子量相一致。结论：我们所制备的Aβ42多克隆抗体能与Aβ42抗原呈特异性结合，这就为研究淀粉样前体蛋白(APP)在生理学和病理生理学上的机制提供了—个有效工具。     

A High-Fat Diet Increases IL-1, IL-6, and TNF-α Production by Increasing NF-κB and Attenuating PPAR-γ Expression in Bone Marrow Mesenchymal Stem Cells

It is well established that a high-fat diet (HFD) can lead to overweight and ultimately to obesity, as well as promoting low-grade chronic inflammation associated with increased levels of such mediators as TNF-α, IL-1, and IL-6. Bone marrow mesenchymal stem cells (MSCs), which are involved in hematopoietic niches and microenvironments, can be affected by these cytokines, resulting in induction of NF-κB and inhibition of PPAR-γ. Because this phenomenon could ultimately lead to suppression of bone marrow adipogenesis, we set out to investigate the effect of an HFD on the expression of PPAR-γ and NF-κB, as well as the production of IL-1, IL-6, and TNF-α in MSCs. Two-month-old male Wistar rats were fed a HFD diet and evaluated by means of leukograms and myelograms along with blood total cholesterol, triglyceride, and C-reactive protein levels. MSCs were isolated, and PPAR-γ and NF-κB were quantified, as well as IL-1, IL-6, and TNF-α production. Animals that were fed a HFD showed higher levels of blood total cholesterol, triglycerides, and C-reactive protein with leukocytosis and bone marrow hyperplasia. MSCs from HFD animals showed increased production of IL-1, IL-6, and TNF-α and increased NF-κB and reduced PPAR-γ expression. Therefore, ingestion of an HFD induces alterations in MSCs that may influence modulation of hematopoiesis.     

Aβ1-42疫苗有效清除PDAPP转基因小鼠脑内Aβ蛋白的沉积

随着人口老化现象的日益严重 ,Ａｌｚｈｅｉｍｅｒ病越来越受到人们的重视。老年斑是Ａｌｚｈｅｉｍｅｒ病的典型病理表现之一。近来Ｅｌａｎ制药厂的ＤａｌｅＳｃｈｅｎｋ等人使用Ａβ1 4 2疫苗有效地清除了ＰＤＡＰＰ转基因小鼠脑内老年斑的沉积。这个实验的第一部分是在 6周龄ＰＤＡＰＰ小鼠老年斑尚未产生之前采用Ａβ1 4 2疫苗 ,进行 11次的免疫接种。作为对照组 ,另外一种与老年斑密切相关的蛋白质血浆淀粉样Ｐ成分ＳＡＰ ,及ＰＢＳ亦被制成疫苗进行与Ａβ1 4 2疫苗同样的免疫程序。经过 11个月的免疫之后 ,Ａβ1 4 2疫苗小鼠体内产生…     

The binding affinity of anti-Aβ1-42 MAb-decorated nanoliposomes to Aβ1-42 peptides in vitro and to amyloid deposits in post-mortem tissue

Amyloid β (Aβ) aggregates are considered as possible targets for therapy and/or diagnosis of Alzheimer disease (AD), and nanoparticles functionalized with Aβ-specific ligands are considered promising vehicles for imaging probes and therapeutic agents. Herein, we characterized the binding properties of nanoliposomes decorated with an anti-Aβ monoclonal antibody (Aβ-MAb). The Aβ-MAb was obtained in mice by immunization with Aβ antigen followed by hybridoma fusion. Surface Plasmon Resonance (SPR) studies confirmed the very high affinity of purified Aβ-MAb for both Aβ monomers and fibrils (K(D)?=?0.08?and 0.13?nm, respectively). The affinity of the biotinylated Aβ-MAb, used thereafter for liposome decoration, was lower although still in the low nanomolar range (K(D)?=?2.1?and 1.6?nm, respectively). Biotin-streptavidin ligation method was used to decorate nanoliposomes with Aβ-MAb, at different densities. IgG-decorated liposomes were generated by the same methodology, as control. Vesicles were monodisperse with mean diameters 124-134?nm and demonstrated good colloidal stability and integrity when incubated with serum proteins. When studied by SPR, Aβ-MAb-liposomes, but not IgG-liposomes, markedly bound to Aβ monomers and fibrils, immobilized on the chip. K(D) values (calculated on Aβ-MAb content) were about 0.5?and 2?nm with liposomes at high and low Aβ-MAb density, respectively. Aβ-MAb-liposome binding to Aβ fibrils was additionally confirmed by ultracentrifugation technique, in which interactions occur in solution under physiological conditions. Moreover, Aβ-MAb-liposomes bound amyloid deposits in post-mortem AD brain samples, confirming the potential of these nanoparticles for the diagnosis and therapy of AD.     

Exendin-4减轻Aβ1-42引起的大鼠工作记忆损伤

正淀粉样β蛋白(amyloidβprotein,Aβ)在阿尔茨海默病(Alzheimer's disease,AD)的发生发展过程中起了关键作用[1],然而,目前仍缺乏拮抗Aβ的有效的治疗手段。近年来研究发现Exendin-4能减缓神经退行性疾病的发展过程,但关于Exendin-4对AD小鼠发挥神经保护     

Aβ_(1-42)寡聚体与阿尔茨海默病研究综述

正阿尔茨海默病(Alzheimer’s disease,AD)是一种多发于老年人的神经系统退行性疾病。临床上表现为记忆障碍、认知障碍、丧失语言能力、丧失认知能力、不能学习新事物及人格和行为等改变的全面性痴呆。在病     

Monomeric Aβ1–42 and RAGE: key players in neuronal differentiation

The aggregation of amyloid-β (Aβ) peptides plays a crucial role in the onset and progression of Alzheimer's disease. Monomeric form of Aβ, indeed, could exert a physiological role. Considering the anti-oligomerization property of all-trans retinoic acid (ATRA), the involvement of monomeric Aβ1–42 in ATRA-induced neuronal differentiation has been investigated. Four-day ATRA treatment increases β-secretase 1 (BACE1) level, Aβ1–42 production, and receptor for advanced glycation end-products (RAGE) expression. RAGE is a well-recognized receptor for Aβ, and the block of both RAGE and Aβ1–42 with specific antibodies strongly impairs neurite formation in ATRA-treated cells. The involvement of Aβ1–42 and RAGE in ATRA-induced morphologic changes has been confirmed treating undifferentiated cells with different molecular assemblies of peptide: 1 μM monomeric, but not oligomeric, Aβ1–42 increases RAGE expression and favors neurite elongation. The block of RAGE completely prevents this effect. Furthermore, our data underline the involvement of the RAGE-dependent adhesion molecule amphoterin-induced gene and open reading frame-1 as downstream effector of both ATRA and Aβ1–42. In conclusion, our findings identify a novel physiological role for monomeric Aβ1–42 and RAGE in neuronal differentiation.     

原花青素抑制Aβ25-35诱导的人神经母细胞瘤细胞系SH-SY5Y分泌Aβ1-42

目的 研究原花青素(PC)对β-淀粉样肽(Aβ25-35)诱导的人神经母细胞瘤细胞系(SH-SY5Y)淀粉样肽产生的影响及可能的作用机制.方法 以Aβ25-35体外处理SH-SY5Y细胞诱导细胞损伤模型,应用PC和(或)Wnt/β-catenin信号通路的内源性抑制剂分泌型蛋白Dickkopf-1(Dkk1)干预.设立...     

Aβ(1-42) inhibition of LTP is mediated by a signaling pathway involving caspase-3, Akt1 and GSK-3β

Amyloid-β(1-42) (Aβ) is thought to be a major mediator of the cognitive deficits in Alzheimer's disease. The ability of Aβ to inhibit hippocampal long-term potentiation provides a cellular correlate of this action, but the underlying molecular mechanism is only partially understood. We found that a signaling pathway involving caspase-3, Akt1 and glycogen synthase kinase-3β is an important mediator of this effect in rats and mice.     

Aβ1-42诱导的AD小鼠模型学习记忆能力的变化

目的研究不同剂量β淀粉样蛋白1-42片段(Aβ1-42)诱导的阿尔茨海默病(AD)小鼠模型的学习记忆功能的变化。方法在C57BL/6J小鼠双侧海马注射不同浓度的Aβ1-42各1μL诱导AD模型,并在对照组注射等量溶剂(生理盐水)。注射7天后,应用水迷宫(MWM)对小鼠进行学习和记忆功能的测定。结果与对照组相比,低剂量Aβ1-42(1μg/μL)处理对小鼠学习记忆功能未产生显著影响;而高剂量Aβ1-42(5μg/μL)处理组与对照组比较,潜伏期明显延长(0.05)、周边活动时间百分比增加(0.05)、平台象限活动时间百分比减少(0.05)、平台穿越次数减少(0.05)。结论双侧海马注射5μg(5μg/μL,1μL)的Aβ1-42能够显著地影响小鼠的学习和记忆功能,是制备小鼠AD模型的有效方法。     

FT-IR光谱法研究TA9902抑制Aβ1-42聚集的分子机制

目的：研究TA9902引起Aβ1-42二级结构变化，了解其抑制Aβ聚集和纤维形成的机制。 方法： 用傅里叶变换红外光谱法（FT-IR）曲线拟合定量分析和特征频谱分析Aβ老化后及TA9902干预后二级结构的变化。 结果： 1 700-1 600 cm-1之间的酰胺I带分析，Aβ1-42单独孵育30 min时，β-折叠片为46.53％；Aβ1-42老化72 h，β-折叠片为65.13％，β-折叠片增加了19.4％。TA9902与Aβ1-42作用β-折叠片为29.04％；与Aβ1-42老化72 h相比，TA9902的存在明显减少β折叠片的含量(下降了36.09％)，β-转角的含量明显升高(升高57.56％)，α-螺旋也略有升高（2.93％）。呈现出明显的β折叠片向β-转角的转化。其它基团特征峰位显示，TA9902中有酮类尤其是饱和链状酮或α-二酮和烷烃类的-CH2和-CH参与了Aβ1-42的分子变构。 结论： TA9902明显抑制Aβ1-42β-折叠的形成，同时也使Aβ1-42肽的侧链基团发生了化学修饰，提示Aβ的聚集和纤维形成与其分子β-折叠的形成和侧链基团发生了化学修饰有关。     

ELISA measurement of specific non-antigen-bound antibodies to Aβ1-42 monomer and soluble oligomers in sera from Alzheimer's disease, mild cognitively impaired, and noncognitively impaired subjects

Background

Neuroinflammation is an important contributor to the development of neurodegenerative diseases, including Alzheimer's disease. Thus, there is a keen interest in identifying compounds, especially from herbal sources, that can inhibit neuroinflammation. Amyloid-β (Aβ) is a major component of the amyloid plaques present in the brains of Alzheimer's disease patients. Here, we examined whether sinomenine, present in a Chinese medicinal plant, prevents oligomeric Aβ-induced microglial activation and confers protection against neurotoxicity.

Methods

Oligomeric amyloid-β was prepared from Aβ(1-42). Intracellular reactive oxygen species production was determined using the dye 2',7'-dichlorodihydrofluorescin diacetate. Nitric oxide level was assessed using the Griess reagent. Flow cytometry was used to examine the levels of inflammatory molecules. BV2-conditioned medium was used to treat hippocampal cell line (HT22) and primary hippocampal cells in indirect toxicity experiments. Toxicity was assessed using MTT reduction and TUNEL assays.

Results

We found that sinomenine prevents the oligomeric Aβ-induced increase in levels of reactive oxygen species and nitric oxide in BV2 microglial cells. In addition, sinomenine reduces levels of Aβ-induced inflammatory molecules. Furthermore, sinomenine protects hippocampal HT22 cells as well as primary hippocampal cells from indirect toxicity mediated by Aβ-treated microglial cells, but has no effect on Aβ-induced direct toxicity to HT22 cells. Finally, we found that conditioned medium from Aβ-treated BV2 cells contains increased levels of nitric oxide and inflammatory molecules, but the levels of these molecules are reduced by sinomenine.

Conclusions

Sinomenine prevents oligomeric Aβ-induced microglial activation, and confers protection against indirect neurotoxicity to hippocampal cells. These results raise the possibility that sinomenine may have therapeutic potential for the treatment of Alzheimer's diseases as well as other diseases that involve neuroinflammation.     

Aβ1-42通过TLR4影响小鼠巨噬细胞RAW264.7炎症因子IL-1β和IL-6释放

目的探讨Aβ1-42对小鼠巨噬细胞RAW264.7向炎症性细胞转变的影响及机制。方法 RAW264.7细胞分别经过LPS与Aβ1-42刺激,RT-PCR和Western blot检测GM-CSF受体CSF2RA和CSF2RB的表达水平,ELISA检测在Aβ1-42刺激下的炎症因子IL-1β、IL-6和TNF-α水平;采用TLR4抑制剂分别干预LPS和Aβ1-42处理后的RAW264.7,检测CSF2RA与CSF2RB受体的表达变化,炎症因子IL-1β、IL-6的释放。结果 RAW264.7细胞表面GM-CSF受体CSF2RB在LPS与Aβ1-42处理后表达水平均比对照组升高(P0.05),而CSF2RA表达没有显著性改变;炎症因子IL-6与IL-1β在Aβ1-42刺激后分泌增加,同时TLR4抑制剂抑制LPS和Aβ1-42对细胞的刺激。结论 Aβ1-42通过TLR4促进小鼠RAW264.7细胞炎症因子IL-6、IL-1β的分泌。     

银杏叶中单体活性成分抑制Aβ1-42聚集和纤维的形成

目的:研究银杏叶提取物中单体活性成分银杏黄酮及银杏内酯对Aβ聚集和纤维形成的影响。方法:运用硫磺素-T荧光分析和透射电镜,通过体外孵育方式观察银杏黄酮、银杏内酯干预Aβ1-42聚集和纤维形成作用。结果:银杏黄酮能明显抑制Aβ1-42的聚集和纤维形成;对老化Aβ纤维亦有明显抑制作用。在电镜下银杏黄酮可使Aβ1-42聚集少,无明显Aβ纤维形成。结论:提示银杏黄酮比银杏内酯具有更强抑制Aβ的聚集和纤维形成的作用,可能是银杏叶提取物中抑制Aβ的聚集的主要活性成分。     

姜黄素胶束对Aβ1-42诱导HT22细胞损伤的保护作用

目的通过β淀粉样蛋白1-42(Aβ_(1-42))诱导HT22细胞损伤,建立氧化应激损伤的体外模型,探讨姜黄素胶束对细胞损伤的保护作用。方法合成姜黄素胶束并评价其体外生物相容性。分别用姜黄素胶束与游离姜黄素预处理细胞后用Aβ_(1-42)诱导HT22细胞损伤,观察对比对照组、模型组、姜黄素胶束组与游离姜黄素组的细胞形态、细胞存活率、胞内活性氧(ROS)水平、线粒体膜电位(MMP)以及乳酸脱氢酶(LDH)释放率和三磷酸腺苷(ATP)酶活力。进一步比较HT22细胞对姜黄素胶束和游离姜黄素摄取能力的差异。结果体外溶血实验显示姜黄素胶束的相对溶血率均低于5%,MTT结果显示姜黄素胶束对HT22细胞存活率基本无影响(P>0.05)。与游离姜黄素相比,姜黄素胶束更能显著改善Aβ_(1-42)诱导的HT22细胞损伤的形态,提高细胞存活率,减少ROS生成、抑制MMP降低、降低LDH释放率并升高ATP酶活力(P<0.05)。在相同条件下HT22细胞更易摄取姜黄素胶束。结论与游离姜黄素相比,姜黄素胶束具有更好的生物相容性,同时更能有效对抗Aβ_(1-42)诱导的氧化应激损伤,这可能与姜黄素胶束能促进细胞摄取有关。姜黄素胶束在临床治疗中具有良好的药用前景。     

中老年小鼠通过长期运动改善Aβ1-42诱导的认知功能障碍

目的　观察中老年小鼠通过长期自主跑轮运动改善β淀粉样蛋白1-42（Aβ1-42）所致认知功能障碍及其机制。 方法　中老年BABL/c小鼠（12月龄）随机分为4组,①溶剂对照静坐组（VS）,②溶剂对照长期自主跑轮运动组（VR）,③Aβ1-42静坐对照组（AS）,④Aβ1-42长期自主跑轮运动组（AR）,按分组条件分别予以自主跑轮或静坐6个月,双侧海马注射Aβ1-42或等量溶剂。注射两周后进行相关检测。 结果　Western blot显示中老年小鼠长期运动致海马泛素化蛋白下降0.2倍（P<0.05）。新物体识别实验显示AR组新物体识别指数高于AS组0.42倍（P<0.05）;Y迷宫自发交替实验显示AR组的入臂正确率较AS组升高0.21倍（P<0.05）。荧光分光光度检测显示AR组海马蛋白酶体活性高于AS组0.18倍（P<0.05）;Western blot显示AR组小鼠海马泛素化蛋白沉积较AS组小鼠减少0.21倍（P<0.05）;免疫组化结果显示AR组Aβ1-42沉积减少（P<0.01）。 结论　中老年小鼠长期自主跑轮运动可维持海马蛋白酶体活性,改善Aβ1-42导致的认知功能障碍。     

A1zheimer病与血管性痴呆患者脑脊液中β-淀粉样蛋白1-42水平的对照研究

目的探讨脑脊液(CSF)中β-淀粉样蛋白1-42(β-amyloid protein1-42, Aβ1-42)的水平对Alzheimer病(AD)的诊断价值,寻找AD理想的生物学标志. 方法将符合美国国立神经病、语言障碍和卒中研究所-老年性痴呆及相关性疾病协会(NINCDS-ADRDA)的"很可能AD"标准的22例AD患者,同时将20例血管性痴呆(vascular dementia, VD)和21例正常对照(normal control, NC)纳入研究.用酶联免疫吸附法(ELISA)分别检测AD组、VD组和NC组CSF中的Aβ1-42水平.同时评定AD、VD组患者的简易智能量表(MMSE)、HACHINSKI缺血量表及临床痴呆量表(CDR)等参数.结果三组CSF中Aβ1-42平均浓度(x±s)(pg/ml)如下AD组343.94±165.87;VD组466.65±222.46;NC组480.40±217.16,AD组明显低于NC组(P<0.05); 虽然AD组低于VD组、VD组低于NC组,但差异均无显著性 (P>0.05); AD组CSF中Aβ1-42浓度与CDR、MMSE评分明显相关(P<0.05).结论Alzheimer病患者CSF中Aβ1-42浓度降低是其重要的实验室表现,可以作为AD的辅助的诊断指标.     

Quantitative trait loci in ABCA1 modify cerebrospinal fluid amyloid-β1-42 and plasma apolipoprotein levels

The ATP-binding cassette transporter A1 encoded by ABCA1 plays an integral role in the efflux of cellular cholesterol and phospholipids, but may also be a central mediator of -amyloid (A) processing. Here, genetic association of the common R219K variant of ABCA1 is shown with cerebrospinal fluid (CSF) A_1–42 levels, reinforcing emerging evidence of a connection between lipid and A metabolism. In support of this finding we demonstrate for the first time that CSF cholesterol and A_1–42 are correlated. To affirm the plausible impact of ABCA1 variation on cholesterol and related traits as well as to empower a survey of possible interactions (e.g. age, gender, and smoking), a large Swedish population consisting of over 2,700 individuals was enlisted and extensive measures of plasma lipid parameters carried out. These analyses revealed that R219K has a strong effect on apolipoprotein B (APOB) and LDL-cholesterol (LDL-C) among smokers (P=0.000055 and P=0.00059, respectively), but not among non-smokers. In contrast, no effect was evident with apolipoprotein A (APOA1) or HDL-cholesterol (HDL-C) levels. Plasma APOB and LDL-C, but not APOA1 and HDL-C, were shown to be markedly elevated in smokers versus non-smokers, affirming that smoking may selectively impact the former pathway. No other genetic markers in ABCA1 exhibit effects as large as R219K, although a modest independent effect of R1587K was observed. Our data illuminate a possible genetic link between A and cholesterol metabolism, but also provide an intriguing example of an environmental exposure that may modify a genotype–phenotype relationship.     

Genistin对Aβ1-42诱发的PC12细胞损伤的神经保护作用

目的探讨Genistin对β淀粉样蛋白片段(Aβ1-42)诱导的PC12细胞损伤的神经保护作用。方法将培养的PC12细胞分为:正常对照组、Aβ1-42处理组和Genistin预处理组。Aβ1-42处理组用Aβ1-42处理细胞,Genistin预处理组在用Aβ1-42处理前2h加入Genistin。使用细胞形态学方法、LDH法和MTT法观察Genistin的神经保护作用。结果单纯Aβ1-4210滋mol/L处理细胞24h,MTT吸光值减小,LDH释放量明显增加,与正常对组比较差异有显著性(P<0.01);细胞形态发生明显改变。用25mmol/LGenistin预处理PC12细胞2h,MTT吸光值与Aβ1-42处理相比明显增加,LDH释放量显著降低,与Aβ1-42处理组相比差异有显著性意义(P<0.01)。结论Genistin在体外抑制Aβ1鄄42对细胞的毒性作用。