c-MYC Copy-Number Gain Is an Independent Prognostic Factor in Patients with Colorectal Cancer

Background

The aim of this study was to determine the incidence and clinicopathological significance of c-MYC gene copy-number (GCN) gain in patients with primary colorectal cancer (CRC).

Methods

The c-MYC GCN was investigated in 367 consecutive CRC patients (cohort 1) by using dual-color silver in situ hybridization. Additionally, to evaluate regional heterogeneity, we examined CRC tissue from 3 sites including the primary cancer, distant metastasis, and lymph-node metastasis in 152 advanced CRC patients (cohort 2). KRAS exons 2 and 3 were investigated for mutations.

Results

In cohort 1, c-MYC gene amplification, defined by a c-MYC:centromere of chromosome 8 ratio ≥ 2.0, was detected in 31 (8.4%) of 367 patients. A c-MYC GCN gain, defined by ≥ 4.0 c-MYC copies/nucleus, was found in 63 (17.2%) patients and was associated with poor prognosis (P = 0.015). Multivariate Cox regression analysis showed that the hazard ratio for c-MYC GCN gain was 2.35 (95% confidence interval, 1.453–3.802; P < 0.001). In a subgroup of stage II-III CRC patients, c-MYC GCN gain was significantly associated with poor prognosis by univariate (P = 0.034) and multivariate (P = 0.040) analyses. c-MYC protein overexpression was observed in 201 (54.8%) out of 367 patients and weakly correlated with c-MYC GCN gain (ρ, 0.211). In cohort 2, the c-MYC genetic status was heterogenous in advanced CRC patients. Discordance between GCN gain in the primary tumor and either distant or lymph-node metastasis was 25.7% and 30.4%, respectively. A similar frequency for c-MYC GCN gain and amplification was observed in CRC patients with both wild-type and mutated KRAS.

Conclusions

c-MYC GCN gain was an independent factor for poor prognosis in consecutive CRC patients and in the stage II-III subgroup. Our findings indicate that the status of c-MYC may be helpful in predicting the patients’ outcome and for managing CRC patients.     

Gestational Weight Gain as an Independent Risk Factor for Macrosomia in Women with Intermediate State Gestational Blood Glucose

Objective: Macrosomia is closely associated with gestational diabetes mellitus (GDM) but its relationship with maternal intermediate state gestational blood glucose (ISGBG; normal fasting blood glucose and 7.8 mmol/L <1 hour blood glucose &lsqb;BG] <10 mmol/L or 6.7 mmol/L <2 hour BG <8.5 mmol/L) is unclear. Here, we analyzed the clinical characteristics and pregnancy outcomes and explored risk factors for macrosomia in women with ISGBG.Methods: A total of 847 women with normal glucose tolerance gestation, 330 with ISGBG, and 99 with GDM were included. Maternal and fetal clinical data were collected and 3-point BG following oral glucose tolerance test, fasting insulin, glycated hemoglobin, and blood lipids profile were measured.Results: The incidence rate of macrosomia among the neonates of women with ISGBG was as high as 10.9%. In the ISGBG group, prepregnancy body mass index (BMI), gestational weight gain (GWG) and the proportion of women with excessive GWG (eGWG) were significantly higher in women with macrosomia compared with those who delivered a normal weight neonate. In women with ISGBG, neonate weight was positively correlated with maternal prepregnancy weight (r = 0.183, P<.01), prepregnancy BMI (r = 0.135, P<.01), and GWG (r = 0.255, P<.01), and negatively correlated with high-density lipoprotein cholesterol (r = -0.172, P<.01). Nonetheless, only eGWG was an independent risk factor (odds ratio = 3.18, 95% confidence interval = 1.26 to 7.88, P<.05) for macrosomia. The risk of macrosomia in pregnant women with prepregnancy BMI <25 kg/m² or BMI ≥25 kg/m² and eGWG was 3.39 and 3.27 times, respectively.Conclusion: The incidence rate of macrosomia is increased in women with ISGBG and eGWG is the strongest independent risk factor. In order to reduce the risk for macrosomia, timely lifestyle intervention to promote appropriate weight gain during pregnancy deserves evaluation.Abbreviations: AUC = area under the curve; BG = blood glucose; 1 hour BG = 1 hour blood glucose after OGTT; 2 hour BG = 2 hour blood glucose after OGTT; BMI = body mass index; CI = confidence interval; eGWG = excessive gestational weight gain; FBG = fasting blood glucose; FINS = fasting insulin; GDM = gestational diabetes mellitus; HbA1c = glycated hemoglobin; HDL-C = high-density lipoprotein cholesterol; HOMA-IR = homeostasis model assessment of insulin resistance index; ISGBG = intermediate state gestation blood glucose; LDL-C = low-density lipoprotein cholesterol; Ln = natural logarithm; MLBW = mature low birth weight; NGTG = normal glucose tolerance gestation; OGTT = oral glucose tolerance test; OR = odds ratio; SD = standard deviation     

疏水性SERS基底检测应用研究进展

本文简要介绍了表面增强拉曼散射(SERS)的拉曼信号增强原理,常规SERS增强基底的研究应用进展;同时介绍了疏水性基底的定义及优势,并重点综述了疏水性SERS基底的分类及研究应用的进展;最后展望了疏水性SERS基底的研究方向和发展趋势。疏水性SERS基底的发展将有望为今后开展面向超低浓度的生化物质检测以及基于人体体液的疾病的灵敏、客观检测诊断提供新方法和新思路。     

Substrate Binding Sites of Leuconostoc Dextransucrase Evaluated by Inhibition Kinetics

Graphical analysis of inhibition kinetics for dextransucrase from Leuconostoc mesenteroides was done with typical inhibitors, competitive and noncompetitive. Based on the plots of Yonetani-Theorell and Semenza-Balthazar, mutual competition between the pairs of inhibitors of identical kinetic type was observed, while combination of competitive and noncompetitive inhibitors gave no significant mutual interactions. By the procedure of Nitta et al., binding sites for competitive and noncompetitive inhibitors were shown to be distant from each other. Moreover, two noncompetitive inhibitors competed with each other for a single binding site on the enzyme. Although biphasic reciprocal plots may suggest rather complicated binding of various inhibitors, the results obtained by the three graphical methods are fully explained when competitive and noncompetitive inhibitors for substrate sucrose bind to the so-called donor- and acceptor-sites of dextransucrase, respectively.     

DNA detection using nanostructured SERS substrates with Rhodamine B as Raman label

A technique is demonstrated to detect DNA hybridization at low concentrations, based on Surface-Enhanced Raman Scattering (SERS) using silicon nanostructures coated with gold-silver as substrate. Standard silicon process technologies were employed to fabricate the SERS substrates featuring nanogaps with a characteristic distance of 15+/-10nm. Target DNA was hybridized with cysteine-modified Peptide Nucleic Acids (PNA), which was previously fixed into the nanogaps as the capture sites. After hybridization, the introduced phosphate groups from the backbone of the target DNA showed strong affinity to an inorganic linker, Zr(4+), so that resulting in the assembly substrate-PNA-DNA-Zr. Since PNA does not possess phosphate groups, the linker is avoided when there is no hybridization from the complimentary DNA. Subsequently, the assembly of substrate-PNA-DNA-Zr was incubated with a Raman label, Rhodamine B (RB). The carboxylic acid group in RB reacted with the linker Zr(4+) allowing this Raman Label to be attached to the assembly substrate-PNA-DNA-Zr. The Raman peaks corresponding to RB were selected to detect the target DNA, with a detection limit of 1x10(-12)M.     

High Purcell Factor Achievement of Notched Cavity Germanium Multiple Quantum Well Plasmon Source

Plasmonics - Recently, many researches are reported on using germanium in silicon-based lasers but acquiring this potential for a plasmonic nanolaser may also be important for development of...     

Diagonally Aligned Squared Metal Nano-pillar with Increased Hotspot Density as a Highly Reproducible SERS Substrate

Metal nanostructure on dielectric substrate with increased hotspot density has drawn considerable research interest in recent years toward the study of surface-enhanced Raman spectroscopy (SERS). In this paper, we report the fabrication of a diagonally aligned squared metal nano-pillar (SMNP) on a dielectric substrate and revealed it as an efficient SERS substrate with increased hotspot density for sensing of Raman active materials. Due to dipolar coupling and lightening rod effect between the neighboring nano-pillars, the localized surface plasmon resonance (LSPR) field intensity increased significantly in the space between two neighboring SMNP which would lead to the enhancement of SERS signal. The SMNP has been fabricated using electron beam lithographic (EBL) technique with hotspot density of 2.45 × 10⁷/mm². With the designed SERS substrate an average enhancement factor (EF) of 3.27 × 10⁸ has been observed with relative standard deviation of ～13 %.     

Preparation of CuO Nanowires/Ag Composite Substrate and Study on SERS Activity

Plasmonics - In this paper, surface-enhanced Raman scattering (SERS) substrates with high detection sensitivity were prepared by thermal oxidation, and magnetron sputtering and the SERS properties...     

Interaction of Creatine Kinase from Monkey Brain with Substrate: Analysis of Kinetics and Fluorescence Polarization

Abstract: Titrimetric determination of the dissociation constants for the binding of substrates to creatine kinase from monkey brain reveals 13-fold and 4-fold synergism in the forward and reverse directions, respectively. This synergism is expressed as a decrease in the K_D for a given substrate in the ternary complex compared with the binary complex and may be a reflection of substrate-induced conformational change. Creatine kinase labeled with two molecules of 5′-iodoacetamidofluorescein displays a blue shift and a decrease in fluorescence intensity upon binding of MgADP, indicative of movement of the dye into a more hydrophobic environment and quenching of the extrinsic fluorescense. Rotational relaxation times determined from analysis of fluorescence polarization of dansylated brain creatine kinase decrease from 212 ± 7 ns to 189 ± 6 ns upon MgADP binding. Dansylated creatine kinase in 0.5% sodium dodecyl sulfate has a rotational relaxation time of 135 ± 6 ns. The rotational relaxation time of dansylated muscle-type isoenzyme is unaffected by MgADP and has the same value as the brain isoenzyme-MgADP complex. Polarization values at 25°C for muscle and brain enzyme labeled with 3 - (4 - maleimidylphenyl) - 7 - diethylamino - 4 - methylcoumarin compared with limiting polarization and polarization of the free dye suggest that the dye rotation is severely restricted in the muscle form, but possesses freedom of rotation in the brain form. These results support the conclusion that compared with the muscle isoenzyme, the brain isoenzyme is more open at the active site and more flexible overall. Binding of MgADP by brain creatine kinase produces a protein more compact across one or both of its rotational axes, thus resembling the conformation of the muscle isoenzyme. It is probable that creatine kinase in the brain, unlike that from muscle, is subject to kinetic regulation accompanied by conformational modification. This suggests that the neurobiochemical role of the brain isoenzyme is distinct from the metabolic function of the muscle isoenzyme.     

Spontaneous Cdc42 Polarization Independent of GDI-Mediated Extraction and Actin-Based Trafficking

The small Rho-family GTPase Cdc42 is critical for cell polarization and polarizes spontaneously in absence of upstream spatial cues. Spontaneous polarization is thought to require dynamic Cdc42 recycling through Guanine nucleotide Dissociation Inhibitor (GDI)-mediated membrane extraction and vesicle trafficking. Here, we describe a functional fluorescent Cdc42 allele in fission yeast, which demonstrates Cdc42 dynamics and polarization independent of these pathways. Furthermore, an engineered Cdc42 allele targeted to the membrane independently of these recycling pathways by an amphipathic helix is viable and polarizes spontaneously to multiple sites in fission and budding yeasts. We show that Cdc42 is highly mobile at the membrane and accumulates at sites of activity, where it displays slower mobility. By contrast, a near-immobile transmembrane domain-containing Cdc42 allele supports viability and polarized activity, but does not accumulate at sites of activity. We propose that Cdc42 activation, enhanced by positive feedback, leads to its local accumulation by capture of fast-diffusing inactive molecules.     

Polarization of Migrating Monocytic Cells Is Independent of PI 3-Kinase Activity

Background

Migration of mammalian cells is a complex cell type and environment specific process. Migrating hematopoietic cells assume a rapid amoeboid like movement when exposed to gradients of chemoattractants. The underlying signaling mechanisms remain controversial with respect to localization and distribution of chemotactic receptors within the plasma membrane and the role of PI 3-kinase activity in cell polarization.

Methodology/Principal Findings

We present a novel model for the investigation of human leukocyte migration. Monocytic THP-1 cells transfected with the α_2A-adrenoceptor (α_2AAR) display comparable signal transduction responses, such as calcium mobilization, MAP-kinase activation and chemotaxis, to the noradrenaline homlogue UK 14''304 as when stimulated with CCL2, which binds to the endogenous chemokine receptor CCR2. Time-lapse video microcopy reveals that chemotactic receptors remain evenly distributed over the plasma membrane and that their internalization is not required for migration. Measurements of intramolecular fluorescence resonance energy transfer (FRET) of α_2AAR-YFP/CFP suggest a uniform activation of the receptors over the entire plasma membrane. Nevertheless, PI 3-kinse activation is confined to the leading edge. When reverting the gradient of chemoattractant by moving the dispensing micropipette, polarized monocytes – in contrast to neutrophils – rapidly flip their polarization axis by developing a new leading edge at the previous posterior side. Flipping of the polarization axis is accompanied by re-localization of PI-3-kinase activity to the new leading edge. However, reversal of the polarization axis occurs in the absence of PI 3-kinase activation.

Conclusions/Significance

Accumulation and internalization of chemotactic receptors at the leading edge is dispensable for cell migration. Furthermore, uniformly distributed receptors allow the cells to rapidly reorient and adapt to changes in the attractant cue. Polarized monocytes, which display typical amoeboid like motility, can rapidly develop a new leading edge facing the highest chemoattractant concentration at any site of the plasma membrane, including the uropod. The process appears to be independent of PI 3-kinase activity.     

EMMPRIN Is an Independent Negative Prognostic Factor for Patients with Astrocytic Glioma

Extracellular matrix metalloproteinase inducer (EMMPRIN), also known as CD147, is a member of the immunoglobulin superfamily that is present on the surface of tumor cells and stimulates adjacent fibroblasts to produce matrix metalloproteinases (MMPs). It has been proved to be associated with tumor invasion and metastasis in various human malignancies. In our study, the protein expression level of EMMPRIN in 306 cases of astrocytic glioma is investigated by immunohistochemistry assay. Statistical analysis was utilized to evaluate the association of EMMPRIN with clinicopathological characteristics and prognosis of patients. It was proved that EMMPRIN protein expression was increased in glioma compared with that in normal brain tissue. Moreover, EMMPRIN immunohistochemical staining was correlated with WHO grade and Karnofsky performance score for strong positive EMMPRIN staining is more frequently detected in glioma of advanced grade or low KPS score. It is also demonstrated that EMMPRIN could be an independent negative prognostic factor in glioma for patients with glioma of strong EMMPRIN staining tend to have high risk of death. These results proved that EMMPRIN is associated with prognosis of glioma, which may also suggest the potential role of EMMPRIN in glioma management.     

顶空及SERS结合快速检测葱属植物-大葱挥发物

建立了常温常压下快速检测新鲜葱属植物-大葱主要挥发性气体的方法。采用顶空瓶在常温常压下收集大葱的挥发物,将挥发物用注射器注入纳米银胶中,进行SERS测量。结果表明大葱的挥发物SERS光谱重现性非常好;将大葱挥发性物的SERS谱与1-丙硫醇(1-Propanethiol)和烯丙基甲基硫醚(allyl methyl sulfide)混合气体的SERS谱相比,具有较好的相似性,说明大葱的挥发物主要由1-丙硫醇和烯丙基甲基硫醚气体组成。利用Gaussian 03软件获得1-丙硫醇-银(1-Propanethiol-Ag)的Raman光谱,计算结果与1-丙硫醇的SERS实验结果对应较好,说明1-丙硫醇在纳米银基底上的增强为化学增强。顶空与SERS结合可直接用于对葱属植物挥发性物的研究。     

Investigation of Tip-Enhanced Raman Spectroscopy on a Silver Nanohole Array Substrate

Plasmonics - Tip-enhanced Raman spectroscopy (TERS) has received much attention due to excellent spatial resolution and high detection sensitivity. However, its performance depends crucially on the...     

Conditioning Increases the Gain of Contraction-Induced Sarcolemmal Substrate Transport in Ultra-Endurance Racing Sled Dogs

Endurance exercise relies on transsarcolemmal flux of substrates in order to avoid depletion of intramuscular reserves. Previous studies of endurance trained sled dogs have shown a remarkable capacity of these dogs to adapt rapidly to endurance exercise by decreasing the utilization of intramuscular reserves. The current study tested the hypothesis that the dogs'' glycogen-sparing phenotype is due to increased sarcolemmal transport of glucose and fatty acids. Basal and exercise-induced transport of glucose and fatty acids into sarcolemmal vesicles was evaluated in racing sled dogs prior to and after 7 months of exercise conditioning. Sarcolemmal substrate transport capacity was measured using sarcolemmal vesicles and radiolabelled substrates, and transporter abundance was measured using Western blot quantification in whole muscle homogenates and the sarcolemmal vesicle preparations. Conditioning resulted in increased basal and exercise-induced transport of both glucose and palmitate. Neither acute exercise nor conditioning resulted in changes in muscle content of GLUT4 or FAT/CD36, but conditioning did result in decreased abundance of both transporters in the sarcolemmal vesicles used for the basal transport assays, and this decrease was further amplified in the vesicles used for the exercise-induced transport assays. These results demonstrate conditioning-induced increases in sarcolemmal transport of oxidizable substrates, as well as increased gain of exercise-induced sarcolemmal transport of these substrates. These results further indicate that increased sarcolemmal transport of oxidizable substrates may be due to either an increased intrinsic capacity of the existing transporters or to a different population of transporters from those investigated.     

SERS Study of Histamine by Using Silver Film over Nanosphere Structure

Optical properties of histamine and l-histidine have been analyzed by using surface-enhanced Raman scattering (SERS). A silver film over nanosphere (AgFON) structure with 120-nm-thick silver film on polystyrene nanospheres 1,000?nm in diameter is fabricated by nanosphere lithography to enhance the Raman signal excited at the laser wavelength of 532?nm. Normal Raman spectrum and the SERS spectrum of histamine and l-histidine were compared. Further, vibration modes of these molecules were calculated by using density functional method. In the SERS experiment, we were able to measure the Raman spectrum with a histamine concentration as less as 100?pM. This sensitivity is higher than that from high-performance liquid chromatography.     

Fabrication of Silver Chevron Arrays as an Efficient and Stable SERS Substrate: Implications in Biological Sensing

Plasmonics - Although glancing angle deposited silver substrates offer an excellent figures for surface enhanced Raman scattering (SERS) sensing, the chemical instability issues of silver...     

对硝基苯硫酚分子内嵌的星形表面增强拉曼散射金 "套娃 "纳米颗粒用于肿瘤拉曼影像的初步研究

目的:制备对硝基苯硫酚(4-Nitrobenzenethiol,4-NBT)分子内嵌的星形表面增强拉曼散射(Surface enhanced Raman Scattering,SERS)金"套娃"纳米颗粒,测定其拉曼增强效果和应用于细胞以及活体肿瘤拉曼影像的可行性。方法:以种子介导法先后制备金纳米星及星形SERS金"套娃"纳米颗粒,采用透射电镜观察其形貌,激光粒度分析仪测定其粒径及Zeta电位,拉曼光谱仪测定其拉曼光谱,考察其对A549细胞的拉曼成像效果,建立A549皮下瘤模型,考察其对活体皮下瘤的成像效果。结果:制备并优化的金纳米星粒径较小,为60.5 nm,其针尖密度较高,以此为核心制备的星形SERS金"套娃"纳米颗粒形态规整,粒径约为66.7nm,Zeta电位约为-16.6 m V,拉曼增强效果提升至其前驱体金纳米星的5.3倍,能够实现对A549细胞及A549皮下瘤的拉曼成像。结论:所制备的星形SERS金"套娃"纳米颗粒形态规整均一,拉曼增强效果较好,能实现对细胞及活体肿瘤的拉曼影像。     

Gold Nanoparticle (AuNP)-Based Surface-Enhanced Raman Scattering (SERS) Probe of Leukemic Lymphocytes

Plasmonics - Identification of cellular surface marker is an effective approach in the early diagnosis of tumor. In this study, based on the finite difference time domain (FDTD) simulation, combing...