Understanding the role of post-CCVD synthetic impurities, functional groups and functionalization-based oxidation debris on the behaviour of carbon nanotubes as a catalyst support in cyclohexene hydrogenation over Pd nanoparticles

Tuning of the surface modification has a striking effect on the physical and chemical properties of CNTs in surface chemical processes.

Preliminary validation of two novel immunoassays for detecting VEGF in human and mouse plasma using single molecule counting technology

e22099

Background: Growth in biomarkers as therapeutic targets and as surrogate markers for efficacy presents a need for increasingly sensitive immunoassays to expand biomarker applicability. Improved immunoassays will provide: (1) better evaluation and validation of new drug candidates, (2) better matching of patients to new therapies, (3) accelerated drug approval (4) earlier diagnosis of at-risk patients, and (5) a deeper understanding of cancer biology. Towards this end, Singulex has developed two ultra- sensitive VEGF Immunoassays for human and mouse vascular endothelial growth factor (VEGF). Here we report the preliminary validation of these two novel assays. Methods: Two novel assays were developed with the Erenna Immunoassay System for detecting VEGF: human (hVEGF) and mouse (mVEGF). Analytical sensitivity, cross-reactivity and precision were determined and compared to an ELISA based VEGF assay. Both the Singulex assay and ELISA assay were used to test a range of specimen types (plasma, cell lysates, conditioned media, and tissue specimens) from humans and mice. Preliminary assays with human plasma and tissue specimens were conducted to compare hVEGF levels between normal and breast cancer samples. Results: The Singulex hVEGF assay had an LOD of 0.1 pg/mL, an LLOQ of 0.3 pg/mL, and 84–107% spike recovery; 90X more sensitive than the ELISA assay. Human VEGF concentrations were quantified in all specimens tested compared to the ELISA, which quantified VEGF in only 8% of plasma samples, but all of the cell lysate samples. The Singulex mVEGF assay had an LOD of 3.5 pg/mL, LLOQ of 5 pg/mL, and 68–111% spike recovery; 3X more sensitive than the ELISA assay. Cross-reactivity for the two assays was minimal for all specimen types tested, except for human plasma samples where the mVEGF assay demonstrated 80–100% CR. Conclusions: We show that the Singulex hVEGF and mVEGF Immunoassays can detect VEGF at or below pg/mL levels, and can effectively quantify VEGF levels in plasma, cell lysates, conditioned media, and tissue samples from mice and humans. These novel assays are an important tool when used to assess tumor and normal breast cancer tissue and plasma.

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Development of ultra-sensitive single molecule immunoassays for the intracellular kinases Akt1/pAkt1 and Erk2/pErk2 for small tissue studies

e22068

Background: The Ras/Raf/MEK/ERK and PI3K/PTEN/AKT kinase cascades are critical pathways in malignant transformation, tumor progression and multi-drug resistance (MDR) in human cancers. Expression and genetic studies have contributed much to our understanding of this role, but further clinical investigations at the post-transcriptional level are necessary. Towards this end, Singulex has developed single molecule immunoassays for total Akt1, pAkt1, total Erk2 and pErk2 utilizing the Erenna Immunoassay System for use in small tissue studies and clinical trials. Methods: Analytical sensitivity, inter- assay precision, linearity and specificity were determined and compared to corresponding ELISA assays. Novel assays were tested on lysates from a variety of commonly utilized cell lines in cancer studies: MCF-7, PBMC, Jurkat, HeLa, and NIH3T3 cells. Results: All four novel assays were significantly more sensitive than the ELISA assay method based upon sample endpoint dilutions. Acceptable precision (<20%CV) was demonstrated for the Akt1/pAkt1 assays in PBMC lysates and for the Erk2/pErk2 assays in MCF-7, HeLa and NIH3T3 lysates. The LLoQ of the Akt1/pAkt1 assay in Jurkat lysates was sufficient to quantify Akt1/pAkt1 from as few as 10–20 cells. Based upon a typical 1mm needle biopsy, this is sufficient to quantify Akt1/pAkt1 from less than 1/1000th of that biopsy. Conclusions: We show that the Singulex Akt1, pAkt1, Erk2 and pErk2 assays are over 50 fold more sensitive than currently available ELISA assays, and specifically quantify analyte in a variety of cell lysates. We have further demonstrated that the Akt1/pAkt1 assay can quantify from as little as 1/1000th of a typical needle biopsy. Thus, these novel assays greatly improve upon pre- existing technology, providing a new tool for clinical trials investigating Ras/Raf/MEK/ERK and PI3K/PTEN/AKT pathways previously limited by ELISA sensitivity.

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Methylglyoxal-mediated growth inhibition in an Escherichia coli cAMP receptor protein mutant

Under certain growth conditions, some strains of Escherichia coli accumulate toxic levels of methylglyoxal. This report characterizes a strain which synthesizes a mutant cAMP receptor protein in an adenylate cyclase deletion background. When cultured in glucose 6-phosphate minimal medium, this strain (222) was prematurely growth arrested due to methylglyoxal production; growth inhibition did not occur when the strain was grown in glucose minimal medium. A comparison of a variety of enzyme and cofactor levels in the related strains 222 (mutant) and 225 (wild-type) grown on either glucose or glucose 6-phosphate medium was carried out. The only difference found that might explain an increase in methylglyoxal accumulation was an elevated level of phosphofructokinase in strain 222 grown on glucose 6-phosphate. Since this enzyme activity probably limits hexose phosphate metabolism, it is suggested that growth inhibition in strain 222 may be due to increased production of triose phosphate, some of which is converted to methylglyoxal.