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61.
Vasandra Devi Karthigesu Maimuna Mendy Marijke Fortuin Hilton C. Whittle Colin R. Howard Lisa M.C. Allison 《FEMS microbiology letters》1995,131(2):127-132
Abstract The functional significance of charged amino acids of the anion-selective porin Omp34 from Acidovorax delafieldii was investigated by means of conductance measurements. Chemical modification of Lys and Arg as well as titration of charges by adjusting the pH value revealed that positively charged amino acid residues determine the major functional properties of the porin. Positive charges are involved in creating the protein surface potential, the selectivity filter inside the channels, and the voltage-sensing and/or gating mechanisms. 相似文献
62.
Delphine Hoorelbeke Elke Decrock Valérie Van Haver Marijke De Bock Luc Leybaert 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2018,1865(11):1805-1814
Photodynamic therapy combines three non-toxic components: light, oxygen and a photosensitizer to generate singlet oxygen and/or other ROS molecules in order to target destruction of cancer cells. The damage induced in the targeted cells can furthermore propagate to non-exposed bystander cells thereby exacerbating the damage. Ca2+ signaling is strongly intertwined with ROS signaling and both play crucial roles in cell death. In this review we aimed to review current knowledge on the role of Ca2+ and ROS signaling, their effect on cell-cell propagation via connexin-linked mechanisms and the outcome in terms of cell death. In general, photodynamic therapy results in an increased cytosolic Ca2+ concentration originating from Ca2+ entry or Ca2+ release from internal stores. While photodynamic therapy can certainly induce cell death, the outcome depends on the cell type and the photosensitizer used. Connexin channels propagating the Ca2+ signal, and presumably regenerating ROS at distance, may play a role in spreading the effect to neighboring non-exposed bystander cells. Given the various cell types and photosensitizers used, there is currently no unified signaling scheme to explain the role of Ca2+ and connexins in the responses following photodynamic therapy. This article is part of a Special Issue entitled: Calcium signaling in health, disease and therapy edited by Geert Bultynck and Jan Parys. 相似文献
63.
Marijke Haas Frits Moolenaar Alex C.A Kluppel Durk Dijkstra Dirk K.F Meijer Dick de Zeeuw 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,693(2):265
One possibility to optimize the therapeutic application of dopaminergic compounds with a catechol function is the reversible protection of this moiety using a prodrug approach. Important features in this respect are a proper chemical stability in the gastrointestinal tract, an adequate release rate after arrival in the blood stream or the possibility to cross the blood–brain barrier. A HPLC method was developed to measure the hydrolysis of prodrugs of dopamine and epinine directly. The method is based on reversed-phase separation followed by post-column ion-pair extraction with a fluorescent counter-ion. The separation of di-isobutyryl esters of dopamine and epinine is obtained within 10 min while the more hydrophobic dopaminergic esters, di-benzoyl and di-pivaloyl dopamine, are retained for 30 min. The precision of the assay measuring 160 ng dibudop and 100 ng ibopamine was 1.2 and 1.0%, respectively. The detection limit of all prodrugs tested was approximately 10 ng. 相似文献
64.
Eric Sulpice Jean-Olivier Contreres Julie Lacour Marijke Bryckaert Gerard Tobelem 《European journal of biochemistry》2004,271(16):3310-3318
The mechanism by which the CXC chemokine platelet factor 4 (PF-4) inhibits endothelial cell proliferation is unclear. The heparin-binding domains of PF-4 have been reported to prevent vascular endothelial growth factor 165 (VEGF(165)) and fibroblast growth factor 2 (FGF2) from interacting with their receptors. However, other studies have suggested that PF-4 acts via heparin-binding independent interactions. Here, we compared the effects of PF-4 on the signalling events involved in the proliferation induced by VEGF(165), which binds heparin, and by VEGF(121), which does not. Activation of the VEGF receptor, KDR, and phospholipase Cgamma (PLCgamma) was unaffected in conditions in which PF-4 inhibited VEGF(121)-induced DNA synthesis. In contrast, VEGF(165)-induced phosphorylation of KDR and PLCgamma was partially inhibited by PF-4. These observations are consistent with PF-4 affecting the binding of VEGF(165), but not that of VEGF(121), to KDR. PF-4 also strongly inhibited the VEGF(165)- and VEGF(121)-induced mitogen-activated protein (MAP) kinase signalling pathways comprising Raf1, MEK1/2 and ERK1/2: for VEGF(165) it interacts directly or upstream from Raf1; for VEGF(121), it acts downstream from PLCgamma. Finally, the mechanism by which PF-4 may inhibit the endothelial cell proliferation induced by both VEGF(121) and VEGF(165), involving disruption of the MAP kinase signalling pathway downstream from KDR did not seem to involve CXCR3B activation. 相似文献
65.
Inaccuracy in analytical results may be due to inadequate monitoring for deficiencies in gas chromatographic determination of prostaglandins.The reasons for discrepancies in the results obtained with gas chromatography with electron capture detection were investigated. 相似文献
66.
67.
Using the Connectivity Map to discover compounds influencing human osteoblast differentiation 下载免费PDF全文
68.
A Physical and Transcriptional Map of the Preaxial Polydactyly Locus on Chromosome 7q36 总被引:15,自引:0,他引:15
69.
Neuronal survival, electrical signaling and synaptic activity require a well-balanced micro-environment in the central nervous system. This is achieved by the blood–brain barrier (BBB), an endothelial barrier situated in the brain capillaries, that controls near-to-all passage in and out of the brain. The endothelial barrier function is highly dependent on signaling interactions with surrounding glial, neuronal and vascular cells, together forming the neuro-glio-vascular unit. Within this functional unit, connexin (Cx) channels are of utmost importance for intercellular communication between the different cellular compartments. Connexins are best known as the building blocks of gap junction (GJ) channels that enable direct cell–cell transfer of metabolic, biochemical and electric signals. In addition, beyond their role in direct intercellular communication, Cxs also form unapposed, non-junctional hemichannels in the plasma membrane that allow the passage of several paracrine messengers, complementing direct GJ communication. Within the NGVU, Cxs are expressed in vascular endothelial cells, including those that form the BBB, and are eminent in astrocytes, especially at their endfoot processes that wrap around cerebral vessels. However, despite the density of Cx channels at this so-called gliovascular interface, it remains unclear as to how Cx-based signaling between astrocytes and BBB endothelial cells may converge control over BBB permeability in health and disease. In this review we describe available evidence that supports a role for astroglial as well as endothelial Cxs in the regulation of BBB permeability during development as well as in disease states. 相似文献
70.
Carla Surlis Keelan McNamara Eoin O’Hara Sinead Waters Marijke Beltman Joseph Cassidy David Kenny 《BMC veterinary research》2017,13(1):391