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styrene


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  • Styrene monomer primarily induces CYP2B1 mRNA in rat liver. 16418063

    To determine the cytochrome P450 (CYP) primarily expressed after styrene exposure, seven forms of hepatic CYP mRNA in rats treated with 600 mg kg(-1) styrene were examined. CYP1A2, CYP2B1/2, CYP2E1 and CYP3A2 mRNA were observed using real-time LightCycler PCR. The amount of CYP2B1 mRNA was significantly increased, 47-fold compared with controls, suggesting that this CYP is the primary cytochrome P450 in rats exposed to styrene. Significant increases in the amount of CYP2E1, CYP1A2 and CYP2B2 mRNA were also observed after styrene exposure, and their increase levels were 3.1-, 1.7- and 1.7-fold higher than controls, respectively. Western blot analysis also indicated that the protein levels of CYP2B1, CYP2B2, CYP2E1 and CYP1A2 showed clear increases after styrene treatment, corresponding to their mRNA expression. CYP2C11 mRNA decreased significantly in rats after styrene exposure. CYP1A1 was detected at the mRNA level in rat liver, but it was not detected at the protein level. The expression of epoxide hydrolase (EH), involved in Phase I drug metabolism, was also examined. EH mRNA increased 2-fold compared with controls after styrene exposure. Styrene thus appears to be a chemical compound that induces multiple CYPs. The results demonstrate that CYP2B1 is the primarily induced CYP form by styrene treatment to rats at acute toxic level.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB10037

  • StyA1 and StyA2B from Rhodococcus opacus 1CP: a multifunctional styrene monooxygenase system. 20675468

    Two-component flavoprotein monooxygenases are emerging biocatalysts that generally consist of a monooxygenase and a reductase component. Here we show that Rhodococcus opacus 1CP encodes a multifunctional enantioselective flavoprotein monooxygenase system composed of a single styrene monooxygenase (SMO) (StyA1) and another styrene monooxygenase fused to an NADH-flavin oxidoreductase (StyA2B). StyA1 and StyA2B convert styrene and chemical analogues to the corresponding epoxides at the expense of FADH2 provided from StyA2B. The StyA1/StyA2B system presents the highest monooxygenase activity in an equimolar ratio of StyA1 and StyA2B, indicating (transient) protein complex formation. StyA1 is also active when FADH2 is supplied by StyB from Pseudomonas sp. VLB120 or PheA2 from Rhodococcus opacus 1CP. However, in both cases the reductase produces an excess of FADH2, resulting in a high waste of NADH. The epoxidation rate of StyA1 heavily depends on the type of reductase. This supports that the FADH2-induced activation of StyA1 requires interprotein communication. We conclude that the StyA1/StyA2B system represents a novel type of multifunctional flavoprotein monooxygenase. Its unique mechanism of cofactor utilization provides new opportunities for biotechnological applications and is highly relevant from a structural and evolutionary point of view.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB318
    Nombre del producto:
    Anti-Tyrosine Hydroxylase Antibody, clone LNC1

  • DNA single- and double-strand breaks by alkaline- and immuno-comet assay in lymphocytes of workers exposed to styrene. 19095051

    Occupational exposure to styrene was studied in 34 workers employed in the production of fiberglass-reinforced plastic sheets and compared to 29 unexposed healthy controls. We evaluated genotoxic effects induced by occupational styrene exposure in lymphocytes by alkaline version of the comet assay to detect single-strand breaks (SSBs), DNA oxidation products (formamido pyrimidine glycosilase (Fpg)- and endonuclease (Endo III)-sensitive sites) and DNA repair kinetics studies, as well as the neutral version of comet assay for DNA double-strand breaks (DSBs). An innovative aspect of this study was the use of immuno-comet assay, a new technique that recognizes DSBs with specific antibody by DAPI/FITC method. The battery of parameters included markers of external and internal exposure. Exposed workers showed significant high levels of SSBs (p0.0001) and DSBs (p0.0001) in neutral- and immuno-comet assay. A drastic decrease in DNA repair activity as compared to controls was observed (180 min vs. 35 min). Styrene workplace concentration significantly correlated with alkaline comet parameters (TM, p=0.013; TI, p=0.008), in negative with TL (p=0.022), and with DNA-base oxidation (TM Endo III, p=0.048 and TI Endo III, p=0.028). There was a significant negative correlation between urinary metabolites (MA+PGA) and TM Endo III (p=0.032) and TI Endo III (p=0.017).
    Tipo de documento:
    Referencia
    Referencia del producto:
    3299

  • Identification of regulatory Hck and PAI-2 proteins in the monocyte response to PEG-containing matrices. 19443025

    Mass spectrometry is a powerful proteomic tool enabling researchers to survey the global proteome of a cell. This technique has only recently been employed to investigate cell-material interactions. We had previously identified material scarcity and limited adherent cells as challenges facing mass spectrometric analysis of cell-material interactions. U937 adherent to tissue culture poly(styrene) was used as a model system for identifying proteins expressed by adherent monocytes and analyzed by HPLC coupled offline to MALDI-ToF/ToF (LC-MALDI). We identified 645 proteins from two cation fractions of crude U937 monocyte cell lysate. Forty three proteins of interest from the 645 were chosen based on literature searches for relevance to monocyte-material inflammation and wound healing. Proteins such as 40S ribosomal protein S19 and tyrosyl tRNA synthetase highlight the ability of LC-MALDI to identify proteins relevant to monocyte-material interactions that are currently unexplored. We used PEG-based semi-interpenetrating polymer networks and PEG-only hydrogels to investigate surface dependent effects on the Src family kinase Hck and plasminogen activator inhibitor-2 (PAI-2) using the pyrazolo pyrimidine small molecule inhibitor PP2 and exogenous urokinase plasminogen activator addition, respectively. Hck is well researched in cell adhesion while PAI-2 is virtually unknown in cell-material interactions. U937 on TCPS and PEG-only hydrogels secreted similar levels of inflammatory cytokines and gelatinase MMP-9. MCP-1 secretion from monocytes on PEG-only hydrogels was Hck independent in contrast to Hck-dependent MCP-1 secretion in U937 on TCPS. Overall, U937 adherent to sIPNs secrete low levels of soluble gelatinase MMP-9, IL-1beta, TNF-alpha, IL-6, and MCP-1 independent of Hck and PAI-2. This work demonstrates significant changes in surface dependent expression of proteins from monocytes adherent to PEG-based materials compared to TCPS.
    Tipo de documento:
    Referencia
    Referencia del producto:
    CC4000
    Nombre del producto:
    Urokinase-type Plasminogen Activator

  • Water in Epoxy styrene

    Tipo de documento:
    Aplicación
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Polystyrene replicas of neuronal basal lamina act as excellent guides for regenerating neurites. 21515424

    Various scaffolds, natural or artificial, have been used for neural repair, including basal lamina scaffolds obtained through extraction of nerves. Here we tested whether plastic casts of such preparations could be used for neurite guidance. To this end, longitudinal micron thick sections of rat sciatic nerve were extracted with detergents and treated with Dnase, yielding an acellular basal lamina master. From the basal lamina master a polydimethylsiloxane (PDMS) mold was made. Then a polystyrene replica was made using the PDMS mold as the master. The polystyrene replica showed high similarity to the master within nanometer resolution as revealed by scanning electron microscopy. Organ cultured mouse dorsal root ganglia grown on the polystyrene replica and the master preparation exhibited guided outgrowth of neurites as assayed by two-dimensional fast Fourier transform analysis on preparations, where the neurites had been visualized by β-III-tubulin staining. The neurites aligned longitudally in the direction of the original basal lamina tubes. Thus, using inexpensive methods it is possible to make replicas of basal lamina which can be used for neurite guidance. This opens a new avenue for nerve reconstruction.Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Correlation of anisotropic cell behaviors with topographic aspect ratio. 19118891

    In this study, we have used nanoimprinting to create a range of micro- and nanoscale gratings, or their combination, in bulk polystyrene plates to investigate anisotropic cell behaviors of human dermal fibroblasts with respect to the aspect ratio (depth/width) of gratings. The depth and width of the polystyrene gratings both show strong effects individually on cell alignment and elongation that are qualitatively similar to the results of other studies. However, consistent quantitative comparison of these individual parameters with different studies is complicated by the diversity of combinations of width and depth that have been tested. Instead, the aspect ratio of the gratings as a unified description of grating topography is a more consistent parameter to interpret topographic dependence of cell morphology. Both cell alignment and elongation increase with increasing aspect ratio, and even a shallow grating (aspect ratio of approximately 0.05) is sufficient to induce 80% cell alignment. Re-plotting data recently published by other groups vs. aspect ratio shows a similar dependence, despite differences in cell types and surface structures. This consistency indicates that aspect ratio is a general factor to characterize cell behaviors. The relationship of cell elongation and alignment with topographic aspect ratio is interpreted in terms of the theory of contact guidance. This model provides simplicity and flexibility in geometry design for devices and materials that interface with cells.
    Tipo de documento:
    Referencia
    Referencia del producto:
    FAK100
    Nombre del producto:
    Actin Cytoskeleton / Focal Adhesion Staining Kit

  • Detection and isolation of lectin-transfected COS cells based on cell adhesion to immobilized glycosphingolipids. 8619482

    Two methods are described, one for detection and one for isolation of COS cells transiently expressing vertebrate lectins. The methods are based on specific cell adhesion to polystyrene microwells or magnetic beads adsorbed with glycosphingolipids. In the first method, glycolipids were adsorbed to wells of 96-well polystyrene plates. A suspension of lectin-transfected COS cells was added and the plate was incubated to allow cell adhesion to occur. The plate was then immersed in buffer, inverted (while immersed), and placed in a fluid-filled Plexiglas centrifugation chamber which was sealed to avoid introducing an air-liquid interface. The chamber, with the inverted plate enclosed, was centrifuged to remove nonadherent cells. The plate was then removed from the carrier (while immersed) and righted, and adherent cells were quantitated enzymatically or immunochemically using a 96-well plate reader. COS cells transfected with an expression plasmid carrying the gene for the rat Kupffer cell lectin (fucose and N-acetylgalactosamine specific) adhered specifically to globotetraosylceramide. Glycolipid- and lectin-specific cell adhesion was readily detected even when COS cells were transfected with a plasmid mixture containing 0.5% lectin-carrying plasmid and 99.5% irrelevant plasmid. This sensitivity will facilitate screening of plasmid pools to detect and isolate plasmids expressing mammalian lectin genes. To isolate COS cells transiently expressing lectin, glycosphingolipids were adsorbed to carboxylated magnetic polystyrene microspheres, which were mixed with the lectin-transfected COS cells. Adherent cells were collected on a fixed magnet and plasmid recovered for subsequent amplification.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB030
    Nombre del producto:
    Anti-DNA Antibody, double stranded, clone BV16-13

  • Progressive degeneration of retinal and superior collicular functions in mice with sustained ocular hypertension. 25722210

    We investigated the progressive degeneration of retinal and superior collicular functions in a mouse model of sustained ocular hypertension.Focal laser illumination and injection of polystyrene microbeads were used to induce chronic ocular hypertension. Retinal ganglion cell (RGC) loss was characterized by in vivo optical coherence tomography (OCT) and immunohistochemistry. Retinal dysfunction was also monitored by the full-field ERG. Retinal ganglion cell light responses were recorded using a 256-channel multielectrode array (MEA), and RGC subtypes were characterized by noncentered spike-triggered covariance (STC-NC) analysis. Single-unit extracellular recordings from superficial layers of the superior colliculus (SC) were performed to examine the receptive field (RF) properties of SC neurons.The elevation of intraocular pressure (IOP) lasted 4 months in mice treated with a combination of laser photocoagulation and microbead injection. Progressive RGC loss and functional degeneration were confirmed in ocular hypertensive (OHT) mice. These mice had fewer visually responsive RGCs than controls. Using the STC-NC analysis, we classified RGCs into ON, OFF, and ON-OFF functional subtypes. We showed that ON and OFF RGCs were more susceptible to the IOP elevation than ON-OFF RGCs. Furthermore, SC neurons of OHT mice had weakened responses to visual stimulation and exhibited mismatched ON and OFF subfields and irregular RF structure.We demonstrated that the functional degeneration of RGCs is subtype-dependent and that the ON and OFF pathways from the retina to the SC were disrupted. Our study provides a foundation to investigate the mechanisms underlying the progressive vision loss in experimental glaucoma.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1585
    Nombre del producto:
    Anti-Brn-3a Antibody, POU-domain protein, clone 5A3.2

  • Inhibited cell spreading on polystyrene nanopillars fabricated by nanoimprinting and in situ elongation. 20739742

    Polymer nanopillars (40-80 nm in diameter and 100 nm in pitch) were fabricated at high density over large areas directly on bulk tissue culture polystyrene plates using nanoimprint lithography. Nanoporous Si molds for imprinting were generated by transfer from an anodic alumina membrane. Ultrahigh aspect ratio polymer nanopillars were formed in a novel procedure using controlled elongation of the imprinted pillars during mold release. The resulting nanopillar arrays show significant changes in surface wettability upon brief O(2) plasma treatment. Human dermal fibroblasts were cultured on the nanopillar surfaces in order to study cell-substrate interaction at the nanoscale. The nanopillar topography shows strong effects on the cell morphology, with pillars of widely varying aspect ratios and surface energies resisting cell spreading. This effect on cell behavior can be rationalized in terms of the cells' requirement to form micron-scale focal adhesions. The study indicates that at the nanoscale, physical factors can supersede the effects of chemical factors on the cell-substratum interaction.
    Tipo de documento:
    Referencia
    Referencia del producto:
    FAK100
    Nombre del producto:
    Actin Cytoskeleton / Focal Adhesion Staining Kit