Functionalized lipid modification of solid phase surfaces for use in chromatography

A solid phase for use in separation has been modified using an aqueous phase adsorption of a headgroup-modified lipid to generate analyte specific surfaces for use as a stationary phase in separations such as high performance liquid chromatography (HPLC) or solid phase extraction (SPE). The aliphatic moiety of the lipid adsorbs strongly to a hydrophobic solid surface, with the hydrophilic and active headgroups orienting themselves toward the more polar mobile phase, thus allowing for interactions with the desired solutes. The surface modification approach is generally applicable to a diversity of selective immobilization applications such as protein immobilization clinical diagnostics and preparative scale HPLC as demonstrated on capillary-channeled fibers, though the general methodology could be implemented on any hydrophobic solid support material

Forward-Backward Correlations and Event Shapes as probes of Minimum-Bias Event Properties

Measurements of inclusive observables, such as particle multiplicities and momentum spectra, have already delivered important information on soft-inclusive ("minimum-bias") physics at the Large Hadron Collider. In order to gain a more complete understanding, however, it is necessary to include also observables that probe the structure of the studied events. We argue that forward-backward (FB) correlations and event-shape observables may be particulary useful first steps in this respect. We study the sensitivity of several different types of FB correlations and two event shape variables - transverse thrust and transverse thrust minor - to various sources of theoretical uncertainty: multiple parton interactions, parton showers, colour (re)connections, and hadronization. The power of each observable to furnish constraints on Monte Carlo models is illustrated by including comparisons between several recent, and qualitatively different, PYTHIA 6 tunes, for pp collisions at sqrt(s) = 900 GeV.Comment: 13 page

Acid-induced Unfolding of the Amino-terminal Domains of the Lethal and Edema Factors of Anthrax Toxin

The two enzymatic components of anthrax toxin, lethal factor (LF) and edema factor (EF), are transported to the cytosol of mammalian cells by the third component, protective antigen (PA). A heptameric form of PA binds LF and/or EF and, under the acidic conditions encountered in endosomes, generates a membrane-spanning pore that is thought to serve as a passageway for these enzymes to enter the cytosol. The pore contains a 14-stranded transmembrane b-barrel that is too narrow to accommodate a fully folded protein, necessitating that LF and EF unfold, at least partly, in order to pass. Here, we describe the pH-dependence of the unfolding of LF N and EF N , the 30 kDa N-terminal PA-binding domains, and minimal translocatable units, of LF and EF. Equilibrium chemical denaturation studies using fluorescence and circular dichroism spectroscopy show that each protein unfolds via a fourstate mechanism: N4I4J4U. The acid-induced N/I transition occurs within the pH range of the endosome (pH 5-6). The I state predominates at lower pH values, and the J and U states are populated significantly only in the presence of denaturant. The I state is compact and has characteristics of a molten globule, as shown by its retention of significant secondary structure and its ability to bind an apolar fluorophore. The N/I transition leads to an overall 60% increase in buried surface area exposure. The J state is expanded significantly and has diminished secondary structure content. We analyze the different protonation states of LF N and EF N in terms of a linked equilibrium proton binding model and discuss the implications of our findings for the mechanism of acidic pH-induced translocation of anthrax toxin. Finally, analysis of the structure of the transmembrane b-barrel of PA shows that it can accommodate a-helix, and we suggest that the steric constraints and composition of the lumen may promote a-helix formation

CD4 inhibits helper T cell activation at lower affinity threshold for full-length T cell receptors than single chain signaling constructs

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DNA Methylation Analysis Reveals Distinct Methylation Signatures in Pediatric Germ Cell Tumors

Background: Aberrant DNA methylation is a prominent feature of many cancers, and may be especially relevant in germ cell tumors (GCTs) due to the extensive epigenetic reprogramming that occurs in the germ line during normal development. Methods: We used the Illumina GoldenGate Cancer Methylation Panel to compare DNA methylation in the three main histologic subtypes of pediatric GCTs (germinoma, teratoma and yolk sac tumor (YST); N = 51) and used recursively partitioned mixture models (RPMM) to test associations between methylation pattern and tumor and demographic characteristics. We identified genes and pathways that were differentially methylated using generalized linear models and Ingenuity Pathway Analysis. We also measured global DNA methylation at LINE1 elements and evaluated methylation at selected imprinted loci using pyrosequencing. Results: Methylation patterns differed by tumor histology, with 18/19 YSTs forming a distinct methylation class. Four pathways showed significant enrichment for YSTs, including a human embryonic stem cell pluripotency pathway. We identified 190 CpG loci with significant methylation differences in mature and immature teratomas (q \u3c 0.05), including a number of CpGs in stem cell and pluripotency-related pathways. Both YST and germinoma showed significantly lower methylation at LINE1 elements compared with normal adjacent tissue while there was no difference between teratoma (mature and immature) and normal tissue. DNA methylation at imprinted loci differed significantly by tumor histology and location. Conclusion: Understanding methylation patterns may identify the developmental stage at which the GCT arose and the at-risk period when environmental exposures could be most harmful. Further, identification of relevant genetic pathways could lead to the development of new targets for therapy

Assessing the effect of interventions for axial spondyloarthritis according to the endorsed ASAS/OMERACT core outcome set: a meta-research study of trials included in Cochrane reviews.

The Assessment of SpondyloArthritis international Society (ASAS) has defined core sets for (i) symptom-modifying anti-rheumatic drugs (SM-ARD), (ii) clinical record keeping, and (iii) disease-controlling anti-rheumatic therapy (DC-ART). These include the following domains for all three core sets: physical function, pain, spinal mobility, spinal stiffness, and patient\u27s global assessment (PGA). The core set for clinical record keeping further includes the domains peripheral joints/entheses and acute phase reactants, and the core set for DC-ART further includes the domains fatigue and spine radiographs/hip radiographs. The Outcome Measures in Rheumatology (OMERACT) endorsed the core sets in 1998.Using empirical evidence from axSpA trials, we investigated the efficacy (i.e., net benefit) according to the ASAS/OMERACT core outcome set for axSpA across all interventions tested in trials included in subsequent Cochrane reviews. For all continuous scales, we combined data using the standardized mean difference (SMD) to meta-analyze outcomes involving the same domains. Also, through meta-regression analysis, we examined the effect of the separate SMD measures (independent variables) on the primary endpoint (log [OR], dependent variable) across all trials.Based on 11 eligible Cochrane reviews, from these, 85 articles were screened; we included 43 trials with 63 randomized comparisons. Mean (SD) number of ASAS/OMERACT core outcome domains measured for SM-ARD/physical therapy trials was 4.2 (1.7). Six trials assessed all proposed domains. Mean (SD) for number of core outcome domains for DC-ART trials was 5.8 (1.7). No trials assessed all nine domains. Eight trials (16%) were judged to have inadequate (i.e., high risk of) selective outcome reporting bias. The most responsible core domains for achieving success in meeting the primary objective per trial were pain, OR (95% CI) 5.19 (2.28, 11.77), and PGA, OR (95% CI) 1.87 (1.14, 3.07). In conclusion, selective outcome reporting (and missing data ) should be reduced by encouraging the use of the endorsed ASAS/OMERACT outcome domains in clinical trials. Overall outcome reporting was good for SM-ARD/physical therapy trials and poor for DC-ART trials. Our findings suggest that both PGA and pain provide a valuable holistic construct for the assessment of improvement beyond more objective measures of spinal inflammation

Cytochrome P450-derived epoxyeicosatrienoic acids and coronary artery disease in humans: a targeted metabolomics study

Cytochrome P450 (CYP)-derived epoxyeicosatrienoic acids (EETs) exhibit potent cardiovascular protective effects in preclinical models, and promoting the effects of EETs has emerged as a potential therapeutic strategy for coronary artery disease (CAD). The relationship between circulating EET levels and CAD extent in humans, however, remains unknown. A panel of free (unesterified) plasma eicosanoid metabolites was quantified in 162 patients referred for coronary angiography, and associations with extent of CAD [no apparent CAD (N = 39), nonobstructive CAD (N = 51), and obstructive CAD (N = 72)] were evaluated. A significant relationship between free EET levels and CAD extent was observed (P = 0.003) such that the presence of obstructive CAD was associated with lower circulating EET levels. This relationship was confirmed in multiple regression analysis where CAD extent was inversely and significantly associated with EET levels (P = 0.013), and with a biomarker of EET biosynthesis (P < 0.001), independent of clinical and demographic factors. Furthermore, quantitative enrichment analysis revealed that these associations were the most pronounced compared with other eicosanoid metabolism pathways. Collectively, these findings suggest that the presence of obstructive CAD is associated with lower EET metabolite levels secondary to suppressed EET biosynthesis. Novel strategies that promote the effects of EETs may have therapeutic promise for patients with obstructive CAD

A fat-tissue sensor couples growth to oxygen availability by remotely controlling insulin secretion

The mechanisms by which organisms adapt their growth according to the availability of oxygen are incompletely understood. Here the authors identify the D rosophila fat body as a tissue regulating growth in response to oxygen sensing via a mechanism involving Hph inhibition, HIF1-a activation and insulin secretion