120 research outputs found

    Dendritic Cell Vaccination, Immune Regulation, and Clinical Outcomes in Ovarian Cancer

    Get PDF
    Clinical optimism for dendritic cell vaccination against ovarian cancer has been tempered by the knowledge that tumors avail themselves of multiple mechanisms of immune evasion, thus blunting the efficacy of therapeutic vaccination. Mechanisms of immune suppression include infiltration by regulatory T cells (Treg) and myeloid suppressor cell populations, expression of co-inhibitory receptors, and expression of indoleamine 2,3-dioxygenase (IDO). Expression of both B7-H1 and IDO are associated with differentiation and recruitment of Treg, and clinical studies have shown that each of these mechanisms correlates independently with increased morbidity and mortality in ovarian cancer patients. In sharp contrast, recent studies have indicated that Th17 cell infiltration in ovarian cancer correlates with improved patient outcomes and prolonged overall survival. Given that IDO plays a pivotal role in the balance between Treg and Th17 immunity, elucidation of the mechanisms that regulate IDO activity and immune suppression may lead to novel adjuvants to boost the clinical efficacy of dendritic cell vaccination against ovarian cancer and other malignancies

    ABCC6 plays a significant role in the transport of nilotinib and dasatinib, and contributes to TKI resistance in vitro, in both cell lines and primary patient mononuclear cells

    Get PDF
    ATP Binding Cassette family efflux proteins ABCB1 and ABCG2 have previously been demonstrated to interact with Tyrosine Kinase Inhibitors (TKIs); however, evidence for the interaction of other potentially relevant drug transporters with TKIs is lacking. Through Taqman transporter array technology we assessed the impact of nilotinib on mRNA expression of ABC transporters, with ABCC6 identified as a transporter of interest. Additionally, increased expression of ABCC6 mRNA was observed during in vitro development of nilotinib resistance in BCR-ABL1-expressing cell lines. K562 cells exposed to gradually increasing concentrations of nilotinib (to 2 μM) expressed up to 57-fold higher levels of ABCC6 mRNA when compared with control cells (p = 0.002). Analogous results were observed in nilotinib resistant K562-Dox cells (up to 33-fold higher levels of ABCC6, p = 0.002). IC50 experiments were conducted on patient mononuclear cells in the absence and presence of three ABCC6 inhibitors: indomethacin, probenecid and pantoprazole. Results demonstrated that all three inhibitors significantly reduced nilotinib IC50 (p<0.001) indicating ABCC6 is likely involved in nilotinib transport. Cell line data confirmed these findings. Similar results were obtained for dasatinib, but not imatinib. Combined, these studies suggest that nilotinib and dasatinib are likely substrates of ABCC6 and to our knowledge, this is the first report of ABCC6 involvement in TKI transport. In addition, ABCC6 overexpression may also contribute to nilotinib and dasatinib resistance in vitro. With nilotinib and dasatinib now front line therapy options in the treatment of CML, concomitant administration of ABCC6 inhibitors may present an attractive option to enhance TKI efficacy.Laura N. Eadie, Phuong Dang, Jarrad M. Goyne, Timothy P. Hughes, Deborah L. Whit

    Influence of repeated application of wetting agents on soil water repellency and microbial community

    Get PDF
    Wetting agents are the primary tool used to control soil water repellency (SWR) and localized dry spot (LDS), especially on sand-based soils. However, the effect of repeated applications of wetting agents on soil microbial populations is unknown. This two-year field experiment investigated six wetting agents representing different chemistry effects on a creeping bentgrass (Agrostis stolonifera L.) putting green with existing SWR. Four out of the six wetting agents improved soil volumetric water content in the second growing season, while others showed no effect. This result was negatively correlated to the development of LDS, and positively correlated to occurrence of an air-borne turf disease. Soil microbial populations, determined by soil phospholipid fatty acid (PLFA) analysis, found that none of the treatments applied caused a shift in microbial populations between fungi and bacteria, or gram-positive and gram-negative bacteria. The stress indicators such as saturated to mono-unsaturated fatty acids were not affected by the wetting agents applied as well. However, the wetting agent that contains alkyl block polymers (ABP; Matador) with proven capability for removal of soil organic coatings showed inhibition of microbial populations at one evaluation timing. This result suggested a temporary restriction in soil carbon availability for soil microorganisms following repeated ABP application, which likely contributed to the elevated LDS development observed. Another wetting agent, a combined product of a nonionic surfactant plus acidifiers (NIS; pHAcid), which is designed to reduce inorganic carbonates while enhancing wetting, elevated all soil microbial populations tested at the end of the experiment, indicating a desirable improvement in soil health. However, repeated application of NIS did not reduce SWR at the conclusion of this experiment, which, in combination with a previous report, suggested a minimal disturbance of soil organic coatings of the hydrophobic sand. Overall, this experiment suggested that soil microbial populations can be affected by wetting agents which may further influence SWR, yet the actual effect on soil microorganisms varies depending on the chemistry of the wetting agents

    Status of Turbulence Modeling for Hypersonic Propulsion Flowpaths

    Get PDF
    This report provides an assessment of current turbulent flow calculation methods for hypersonic propulsion flowpaths, particularly the scramjet engine. Emphasis is placed on Reynolds-averaged Navier-Stokes (RANS) methods, but some discussion of newer meth- ods such as Large Eddy Simulation (LES) is also provided. The report is organized by considering technical issues throughout the scramjet-powered vehicle flowpath including laminar-to-turbulent boundary layer transition, shock wave / turbulent boundary layer interactions, scalar transport modeling (specifically the significance of turbulent Prandtl and Schmidt numbers) and compressible mixing. Unit problems are primarily used to conduct the assessment. In the combustor, results from calculations of a direct connect supersonic combustion experiment are also used to address the effects of turbulence model selection and in particular settings for the turbulent Prandtl and Schmidt numbers. It is concluded that RANS turbulence modeling shortfalls are still a major limitation to the accuracy of hypersonic propulsion simulations, whether considering individual components or an overall system. Newer methods such as LES-based techniques may be promising, but are not yet at a maturity to be used routinely by the hypersonic propulsion community. The need for fundamental experiments to provide data for turbulence model development and validation is discussed

    BCR-ABL1 genomic DNA PCR response kinetics during first-line imatinib treatment of chronic myeloid leukemia

    Get PDF
    Accurate quantification of minimal residual disease during treatment of chronic myeloid leukaemia guides clinical decisions. The conventional minimal residual disease method, RQ-PCR for BCR-ABL1 mRNA, reflects a composite of the number of circulating leukemic cells and the BCR-ABL1 transcripts per cell. BCR-ABL1 genomic DNA only reflects leukemic cell number. We used both methods in parallel to determine the relative contribution of the leukemic cell number to molecular response. BCR-ABL1 DNA PCR and RQ-PCR were monitored up to 24 months in 516 paired samples from 59 newly-diagnosed patients treated with first-line imatinib in the TIDEL-II study. In the first 3 months of treatment BCR-ABL1 mRNA values declined more rapidly than DNA. By 6 months the two measures aligned closely. The expression of BCR-ABL1 mRNA was normalized to cell number to generate an expression ratio. The expression of e13a2 BCR-ABL1 was lower than that of e14a2 transcripts at multiple time points during treatment. BCR-ABL1 DNA was quantifiable in 48% of samples with undetectable BCR-ABL1 mRNA, resulting in minimal residual disease being quantifiable for an additional 5-18 months (median 12 months). These parallel studies show for the first time that the rapid decline in BCR-ABL1 mRNA over the first 3 months of treatment is due to a reduction in both cell number and transcript level per cell, whereas beyond 3 months falling levels of BCR-ABL1 mRNA are predominantly due to depletion of leukaemic cells.Ilaria S. Pagani, Phuong Dang, Ivar O. Kommers, Jarrad M. Goyne, Mario Nicola, Verity A. Saunders, Jodi Braley, Deborah L. White, David T. Yeung, Susan Branford, Timothy P. Hughes, and David M. Ros

    The Origin and Contribution of Cancer-Associated Fibroblasts in Colorectal Carcinogenesis

    Get PDF
    Background & Aims: Cancer-associated fibroblasts (CAFs) play an important role in colorectal cancer (CRC) progression and predict poor prognosis in CRC patients. However, the cellular origins of CAFs remain unknown, making it challenging to therapeutically target these cells. Here, we aimed to identify the origins and contribution of colorectal CAFs associated with poor prognosis. Methods: To elucidate CAF origins, we used a colitis-associated CRC mouse model in 5 different fate-mapping mouse lines with 5-bromodeoxyuridine dosing. RNA sequencing of fluorescence-activated cell sorting–purified CRC CAFs was performed to identify a potential therapeutic target in CAFs. To examine the prognostic significance of the stromal target, CRC patient RNA sequencing data and tissue microarray were used. CRC organoids were injected into the colons of knockout mice to assess the mechanism by which the stromal gene contributes to colorectal tumorigenesis. Results: Our lineage-tracing studies revealed that in CRC, many ACTA2+ CAFs emerge through proliferation from intestinal pericryptal leptin receptor (Lepr)+ cells. These Lepr-lineage CAFs, in turn, express melanoma cell adhesion molecule (MCAM), a CRC stroma-specific marker that we identified with the use of RNA sequencing. High MCAM expression induced by transforming growth factor β was inversely associated with patient survival in human CRC. In mice, stromal Mcam knockout attenuated orthotopically injected colorectal tumoroid growth and improved survival through decreased tumor-associated macrophage recruitment. Mechanistically, fibroblast MCAM interacted with interleukin-1 receptor 1 to augment nuclear factor κB–IL34/CCL8 signaling that promotes macrophage chemotaxis. Conclusions: In colorectal carcinogenesis, pericryptal Lepr-lineage cells proliferate to generate MCAM+ CAFs that shape the tumor-promoting immune microenvironment. Preventing the expansion/differentiation of Lepr-lineage CAFs or inhibiting MCAM activity could be effective therapeutic approaches for CRC

    Quantification of the 2-Deoxyribonolactone and Nucleoside 5 '-Aldehyde Products of 2-Deoxyribose Oxidation in DNA and Cells by Isotope-Dilution Gas Chromatography Mass Spectrometry: Differential Effects of gamma-Radiation and Fe2+-EDTA

    Get PDF
    The oxidation of 2-deoxyribose in DNA has emerged as a critical determinant of the cellular toxicity of oxidative damage to DNA, with oxidation of each carbon producing a unique spectrum of electrophilic products. We have developed and validated an isotope-dilution gas chromatography-coupled mass spectrometry (GC−MS) method for the rigorous quantification of two major 2-deoxyribose oxidation products: the 2-deoxyribonolactone abasic site of 1′-oxidation and the nucleoside 5′-aldehyde of 5′-oxidation chemistry. The method entails elimination of these products as 5-methylene-2(5H)-furanone (5MF) and furfural, respectively, followed by derivatization with pentafluorophenylhydrazine (PFPH), addition of isotopically labeled PFPH derivatives as internal standards, extraction of the derivatives, and quantification by GC−MS analysis. The precision and accuracy of the method were validated with oligodeoxynucleotides containing the 2-deoxyribonolactone and nucleoside 5′-aldehyde lesions. Further, the well-defined 2-deoxyribose oxidation chemistry of the enediyne antibiotics, neocarzinostatin and calicheamicin γ1I, was exploited in control studies, with neocarzinostatin producing 10 2-deoxyribonolactone and 300 nucleoside 5′-aldehyde per 106 nt per μM in accord with its established minor 1′- and major 5′-oxidation chemistry. Calicheamicin unexpectedly caused 1′-oxidation at a low level of 10 2-deoxyribonolactone per 106 nt per μM in addition to the expected predominance of 5′-oxidation at 560 nucleoside 5′-aldehyde per 106 nt per μM. The two hydroxyl radical-mediated DNA oxidants, γ-radiation and Fe2+−EDTA, produced nucleoside 5′-aldehyde at a frequency of 57 per 106 nt per Gy (G-value 74 nmol/J) and 3.5 per 106 nt per μM, respectively, which amounted to 40% and 35%, respectively, of total 2-deoxyribose oxidation as measured by a plasmid nicking assay. However, γ-radiation and Fe2+−EDTA produced different proportions of 2-deoxyribonolactone at 7% and 24% of total 2-deoxyribose oxidation, respectively, with frequencies of 10 lesions per 106 nt per Gy (G-value, 13 nmol/J) and 2.4 lesions per 106 nt per μM. Studies in TK6 human lymphoblastoid cells, in which the analytical data were corrected for losses sustained during DNA isolation, revealed background levels of 2-deoxyribonolactone and nucleoside 5′-aldehyde of 9.7 and 73 lesions per 106 nt, respectively. γ-Irradiation of the cells caused increases of 0.045 and 0.22 lesions per 106 nt per Gy, respectively, which represents a 250-fold quenching effect of the cellular environment similar to that observed in previous studies. The proportions of the various 2-deoxyribose oxidation products generated by γ-radiation are similar for purified DNA and cells. These results are consistent with solvent exposure as a major determinant of hydroxyl radical reactivity with 2-deoxyribose in DNA, but the large differences between γ-radiation and Fe2+−EDTA suggest that factors other than hydroxyl radical reactivity govern DNA oxidation chemistry.National Institute of Environmental Health Sciences (ES002109)National Center for Research Resources (U.S.) (RR023783-01)National Center for Research Resources (U.S.) (RR017905-01)National Cancer Institute (U.S.) (CA103146

    Modeling, control and certification of an electrical decentralized microgrid with random exogenous inputs and constrained information

    Get PDF
    Depuis plusieurs années, le secteur de l’énergie subit des changements importants. La prise de conscience du réchauffement climatique, la volonté d’introduire un mix énergétique permettant de réduire les émissions de gaz à effet de serre, mais aussi la raréfaction des sources d’énergies fossiles, tendent à favoriser la production d’électricité à partir d’énergies renouvelables. Les « microgrids » ou micro­réseaux électriques sont une de ces opportunités de nouveaux marchés, sur lequel souhaite se positionner fortement Schneider Electric.Les microgrids sont des versions à échelles réduites d’un réseau national, comportant des objectifs particuliers comme la sécurisation de l’énergie, la baisse d’émissions de gaz à effet de serre, etc. Ils sont composés de diverses sources de puissance : renouvelable (PV ; éolien, etc.), générateurs diesel, mais aussi de stockage et de consommateurs. Ils peuvent être connectés à un réseau principale, ou îlotés. Les microgrids îlotés étant intrinsèquement composés de producteurs à base d’énergie renouvelable et donc de convertisseurs statiques, l’inertie naturelle du réseau est très faible, comparée à celle d’un réseau classique composé de machine tournante. Dans ce type de configuration, un appel de charge, une baisse soudaine de production due à l’intermittence de certaines énergies, peut déstabiliser le réseau et créer des réactions en chaîne aboutissant à une perte totale du réseau.Parmi les marchés visés des microgrid, celui des îles, dont le réseau électrique est majoritairement assuré par des groupes électrogènes, présente l’objectif attirant d’améliorer une base existante en ajoutant des sources renouvelables à la production. Ces réseaux font face à de fortes contraintes de communication qui peut être difficile à établir, voir non existante. Ainsi, les commandes conventionnelles d’un microgrid ne permettent pas de répondre à la problématique présentée.Les travaux se résument en quatre étapes principales, dans un premier temps, différents modèles de simulations des sous-systèmes seront définis pour répondre à la problématique.Ces modèles serviront ensuite à la définition des lois de contrôle-commande d’un microgrid décentralisé à communication limité, et permettront, entre autres, de comparer les performances d’un tel contrôle avec un contrôle centralisé classique.La troisième étape de la thèse présentera la certification probabiliste des algorithmes décentralisés, afin d’assurer les performances souhaitées.Enfin, les travaux se termineront par des résultats de simulation et une phase d’expérimentation réelle, avec la mise en place d’un microgrid d’une puissance totale de 100kW, pour valider le fonctionnement des algorithmes.Since many years, the energy sector is undergoing significant changes. Awareness of global warming, the objective to use reduce greenhouse gas but also the scarcity of fossil energy, encourage the world to promote the use of more and more renewable energies. Electric microgrid are one of the opportunities new market on which Schneider Electric wants to launch.Microgrid are a scaled-down version of a national grid with specific objectives such as energy security, lower greenhouse gas emissions and so on. They are composed of several renewable sources (photovoltaic, wind for example), generators set, but also storage and consumers. They can be connected to a main grid or islanded. Since islanded microgrid are intrinsically composed of renewable producers with static converters, the natural grid inertia is particularly low compared to that of a classic grid with rotating machine. With this consideration, a load impact or a sudden drop of production due to renewable intermittency can destabilize the network and create chain reactions leading to a total grid blackout.Among the microgrids target markets, island whose electricity production is mostly provided by generators set presents the objective of improving an existing grid by adding renewable sources to production. These grid face strong communication constraints which can be difficult to establish, unreliable or non-existent. Thus, conventional microgrid commands do not allow to answer the presented problem.Objective of this thesis is to design the control algorithms of islanded microgrid without communication to ensure both frequency stability and to maximize renewable energy use.The presented work can be summarized in four main stages. First, several simulation models of microgrid subsystem will be defined for islanded microgrid analysis.These models will then be used to define control laws of a decentralized microgrid without communication. They will be used, inter alia, to compare performances of this decentralized control with a conventional centralized control.The third stage of the thesis will present the probabilistic certification of the decentralized algorithms in order to guarantee the desired performance.Finally, the work will end with simulation results and a real experimentation phase with the test on a 100 kVA microgrid to validate operation of algorithms

    Skin-friction measurements in high-enthalpy hypersonic boundary layers

    No full text
    Skin-friction measurements are reported for high-enthalpy and high-Mach-number laminar, transitional and turbulent boundary layers. The measurements were performed in a free-piston shock tunnel with air-flow Mach number, stagnation enthalpy and Reynolds numbers in the ranges of 4.4-6.7, 3-13 MJ kg(-1) and 0.16 x 10(6)-21 x 10(6), respectively. Wall temperatures were near 300 K and this resulted in ratios of wall enthalpy to flow-stagnation enthalpy in the range of 0.1-0.02. The experiments were performed using rectangular ducts. The measurements were accomplished using a new skin-friction gauge that was developed for impulse facility testing. The gauge was an acceleration compensated piezoelectric transducer and had a lowest natural frequency near 40 kHz. Turbulent skin-friction levels were measured to within a typical uncertainty of +/-7%. The systematic uncertainty in measured skin-friction coefficient was high for the tested laminar conditions; however, to within experimental uncertainty, the skin-friction and heat-transfer measurements were in agreement with the laminar theory of van Driest (1952). For predicting turbulent skin-friction coefficient, it was established that, for the range of Mach numbers and Reynolds numbers of the experiments, with cold walls and boundary layers approaching the turbulent equilibrium state, the Spalding & Chi (1964) method was the most suitable of the theories tested. It was also established that if the heat transfer rate to the wall is to be predicted, then the Spalding & Chi (1964) method should be used in conjunction with a Reynolds analogy factor near unity. If more accurate results are required, then an experimentally observed relationship between the Reynolds analogy factor and the skin-friction coefficient may be applied
    • …
    corecore