207 research outputs found

    The Characteristics of Mechanical Grinding on Kaolinite Structure and Thermal Behavior

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    AbstractThe relationship between kaolinite structure and the temperature of thermal transformation of phase was discussed in this paper through grinding and heating treatment. The results show that the structure of kaolinite is destroyed rapidly with increasing mechanical grinding time, and the kaolinite structure collapses completely after 1h grinding. The temperature of thermal transformation of phase decreases with the destruction of kaolinite structure. This result has a great significance for the utilization of kaolinite associated with coal measures in China

    A quantitative method using one marker for simultaneous assay of steroidal saponins in rhizoma paridis

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    Current quality control patterns are limited to industrial application, for most the natural chemical reference substances are expensive and unavailable. Here in, quantitative analysis of multi-components with single marker (QAMS) method, is established and validated to simultaneously determine five steroidal saponins (Paris-VII, Paris-H, Paris-II, Dioscin , Paris-I) in Rhizoma Paridis. Using Paris-I as the contrast, the relative correction factors (RCF) of the other four steroidal saponins are determined by HPLC-UV. With in the linear ranges, the values of RCF of Paris-I to Paris-VII, Paris-H, Paris-II and Dioscin are 0.877, 1.087, 0.975 and 1.127, respectively. The RCF has a good reproducibility in various instruments, chromatographic columns (RSD = 0.88 % ~ 4.52 %). According to their RCF, five steroidal saponins are simultaneously determined in Rhizoma Paridis by one marker.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    A quantitative method using one marker for simultaneous assay of steroidal saponins in rhizoma paridis

    Get PDF
    Current quality control patterns are limited to industrial application, for most the natural chemical reference substances are expensive and unavailable. Here in, quantitative analysis of multi-components with single marker (QAMS) method, is established and validated to simultaneously determine five steroidal saponins (Paris-VII, Paris-H, Paris-II, Dioscin , Paris-I) in Rhizoma Paridis. Using Paris-I as the contrast, the relative correction factors (RCF) of the other four steroidal saponins are determined by HPLC-UV. With in the linear ranges, the values of RCF of Paris-I to Paris-VII, Paris-H, Paris-II and Dioscin are 0.877, 1.087, 0.975 and 1.127, respectively. The RCF has a good reproducibility in various instruments, chromatographic columns (RSD = 0.88 % ~ 4.52 %). According to their RCF, five steroidal saponins are simultaneously determined in Rhizoma Paridis by one marker.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Extracellular Matrix Protein Tenascin C Increases Phagocytosis Mediated by CD47 Loss of Function in Glioblastoma.

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    Glioblastomas (GBM) are highly infiltrated by myeloid-derived innate immune cells that contribute to the immunosuppressive nature of the brain tumor microenvironment (TME). CD47 has been shown to mediate immune evasion, as the CD47-SIRPα axis prevents phagocytosis of tumor cells by macrophages and other myeloid cells. In this study, we established CD47 homozygous deletion (CD47-/-) in human and mouse GBM cells and investigated the impact of eliminating the "don't eat me" signal on tumor growth and tumor-TME interactions. CD47 knockout (KO) did not significantly alter tumor cell proliferation in vitro but significantly increased phagocytosis of tumor cells by macrophages in cocultures. Compared with CD47 wild-type xenografts, orthotopic xenografts derived from CD47-/- tumor cells grew significantly slower with enhanced tumor cell phagocytosis and increased recruitment of M2-like tumor-associated microglia/macrophages (TAM). CD47 KO increased tumor-associated extracellular matrix protein tenascin C (TNC) in xenografts, which was further examined in vitro. CD47 loss of function upregulated TNC expression in tumor cells via a Notch pathway-mediated mechanism. Depletion of TNC in tumor cells enhanced the growth of CD47-/- xenografts in vivo and decreased the number of TAM. TNC knockdown also inhibited phagocytosis of CD47-/- tumor cells in cocultures. Furthermore, TNC stimulated release of proinflammatory factors including TNFα via a Toll-like receptor 4 and STAT3-dependent mechanism in human macrophage cells. These results reveal a vital role for TNC in immunomodulation in brain tumor biology and demonstrate the prominence of the TME extracellular matrix in affecting the antitumor function of brain innate immune cells. SIGNIFICANCE: These findings link TNC to CD47-driven phagocytosis and demonstrate that TNC affects the antitumor function of brain TAM, facilitating the development of novel innate immune system-based therapies for brain tumors

    Targeting UDP-α-D-glucose 6-dehydrogenase inhibits glioblastoma growth and migration

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    UDP-glucose 6-dehydrogenase (UGDH) produces UDP-α-D-glucuronic acid, the precursors for glycosaminoglycans (GAGs) and proteoglycans of the extracellular matrix. Elevated GAG formation has been implicated in a variety of human diseases, including glioblastoma (GBM). In our previous study, we found that Krüppel-like factor 4 (KLF4) promotes GBM cell migration by binding to methylated DNA, mainly methylated CpGs (mCpG) and transactivating gene expression. We identified UDGH as one of the downstream targets of KLF4-mCpG binding activity. In this study, we show that KLF4 upregulates UGDH expression in a mCpG-dependent manner, and UGDH is required for KLF4-induced cell migration in vitro. UGDH knockdown decreases GAG abundance in GBM cells, as well as cell proliferation and migration in vitro. In intracranial xenografts, reduced UGDH inhibits tumor growth and migration, accompanied by a decrease in the expression of extracellular matrix proteins such as tenascin C, brevican. Our studies demonstrate a novel DNA methylation-dependent UGDH upregulation by KLF4. Developing UGDH antagonists to decrease the synthesis of extracellular matrix components will be a useful strategy for GBM therapy

    Biotransformation of rhizoma Paridis saponins by rat intestinal microflora

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    Rhizoma Paridis saponins (RPS) were considered to be the principal bioactive components of Paris polyphylla Smith var. yunnanensis. Intestinal microflora-mediated metabolism may affect their pharmacological activities in vivo. In this study, the biotransformation of RPS by rat intestinal microflora in vitro was investigated. A high-performance liquid chromatography with electrospray ionization combined with mass spectrometry (HPLC-ESI-MS) method was developed to identify RPS and their metabolites. The metabolism of RPS by rat intestinal microflora was mainly based on cleavage of the oligosaccharide chains which is connected to the C-3 or C-22 position. However, the elimination of the glucose molecule at C-26 and F-ring closure occurred firstly in prototype saponins. In addition, the biotransformation routes of RPS in the presence of rat intestinal microflora were elaborated, from which RPS were presumed primarily responsible for the metabolism via α-rhamnosidase and β-glycosidase activities. These results would contribute to understanding of the mechanisms in bioavailability of herbal drugs and their metabolites.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    A quantitative method using one marker for simultaneous assay of steroidal saponins in rhizoma paridis

    Get PDF
    Current quality control patterns are limited to industrial application, for most the natural chemical reference substances are expensive and unavailable. Here in, quantitative analysis of multi-components with single marker (QAMS) method, is established and validated to simultaneously determine five steroidal saponins (Paris-VII, Paris-H, Paris-II, Dioscin , Paris-I) in Rhizoma Paridis. Using Paris-I as the contrast, the relative correction factors (RCF) of the other four steroidal saponins are determined by HPLC-UV. With in the linear ranges, the values of RCF of Paris-I to Paris-VII, Paris-H, Paris-II and Dioscin are 0.877, 1.087, 0.975 and 1.127, respectively. The RCF has a good reproducibility in various instruments, chromatographic columns (RSD = 0.88 % ~ 4.52 %). According to their RCF, five steroidal saponins are simultaneously determined in Rhizoma Paridis by one marker.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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