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Search Results: 1 - 10 of 678815 matches for " Antoine A. F. de Vries "
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Rapid and Sensitive Lentivirus Vector-Based Conditional Gene Expression Assay to Monitor and Quantify Cell Fusion Activity
Manuel A. F. V. Gon?alves,Josephine M. Janssen,Maarten Holkers,Antoine A. F. de Vries
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010954
Abstract: Cell-to-cell fusion is involved in multiple fundamental biological processes. Prominent examples include osteoclast and giant cell formation, fertilization and skeletal myogenesis which involve macrophage, sperm-egg and myoblast fusion, respectively. Indeed, the importance of cell fusion is underscored by the wide range of homeostatic as well as pathologic processes in which it plays a key role. Therefore, rapid and sensitive systems to trace and measure cell fusion events in various experimental systems are in demand. Here, we introduce a bipartite cell fusion monitoring system based on a genetic switch responsive to the site-specific recombinase FLP. To allow flexible deployment in both dividing as well as non-dividing cell populations, inducer and reporter modules were incorporated in lentivirus vector particles. Moreover, the recombinase-inducible transcription units were designed in such a way as to minimize basal activity and chromosomal position effects in the “off” and “on” states, respectively. The lentivirus vector-based conditional gene expression assay was validated in primary human mesenchymal stem cells and in a differentiation model based on muscle progenitor cells from a Duchenne muscular dystrophy patient using reporter genes compatible with live- and single-cell imaging and with whole population measurements. Using the skeletal muscle cell differentiation model, we showed that the new assay displays low background activity, a 2-log dynamic range, high sensitivity and is amenable to the investigation of cell fusion kinetics. The utility of the bipartite cell fusion monitoring system was underscored by a study on the impact of drug- and RNAi-mediated p38 MAPK inhibition on human myocyte differentiation. Finally, building on the capacity of lentivirus vectors to readily generate transgenic animals the present FLP-inducible system should be adaptable, alone or together with Cre/loxP-based assays, to cell lineage tracing and conditional gene manipulation studies in vivo.
Development of a Lentivirus Vector-Based Assay for Non-Destructive Monitoring of Cell Fusion Activity
Zeinab Neshati, Jia Liu, Guangqian Zhou, Martin J. Schalij, Antoine A. F. de Vries
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0102433
Abstract: Cell-to-cell fusion can be quantified by endowing acceptor and donor cells with latent reporter genes/proteins and activators of these genes/proteins, respectively. One way to accomplish this goal is by using a bipartite lentivirus vector (LV)-based cell fusion assay system in which the cellular fusion partners are transduced with a flippase-activatable Photinus pyralis luciferase (PpLuc) expression unit (acceptor cells) or with a recombinant gene encoding FLPeNLS+, a nuclear-targeted and molecularly evolved version of flippase (donor cells). Fusion of both cell populations will lead to the FLPe-dependent generation of a functional PpLuc gene. PpLuc activity is typically measured in cell lysates, precluding consecutive analysis of one cell culture. Therefore, in this study the PpLuc-coding sequence was replaced by that of Gaussia princeps luciferase (GpLuc), a secretory protein allowing repeated analysis of the same cell culture. In myotubes the spread of FLPeNLS+ may be limited due to its nuclear localization signal (NLS) causing low signal outputs. To test this hypothesis, myoblasts were transduced with LVs encoding either FLPeNLS+ or an NLS-less version of FLPe (FLPeNLS?) and subsequently co-cultured in different ratios with myoblasts containing the FLPe-activatable GpLuc expression cassette. At different times after induction of cell-to-cell fusion the GpLuc activity in the culture medium was determined. FLPeNLS+ and FLPeNLS? both activated the latent GpLuc gene but when the percentage of FLPe-expressing myoblasts was limiting, FLPeNLS+ generally yielded slightly higher signals than FLPeNLS? while at low acceptor-to-donor cell ratios FLPeNLS? was usually superior. The ability of FLPeNLS+ to spread through myofibers and to induce reporter gene expression is thus not limited by its NLS. However, at high FLPe concentrations the presence of the NLS negatively affected reporter gene expression. In summary, a rapid and simple chemiluminescence assay for quantifying cell-to-cell fusion progression based on GpLuc has been developed.
Targeted Chromosomal Insertion of Large DNA into the Human Genome by a Fiber-Modified High-Capacity Adenovirus-Based Vector System
Manuel A. F. V. Gon?alves, Maarten Holkers, Gijsbert P. van Nierop, Roeland Wieringa, Maria G. Pau, Antoine A. F. de Vries
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0003084
Abstract: A prominent goal in gene therapy research concerns the development of gene transfer vehicles that can integrate exogenous DNA at specific chromosomal loci to prevent insertional oncogenesis and provide for long-term transgene expression. Adenovirus (Ad) vectors arguably represent the most efficient delivery systems of episomal DNA into eukaryotic cell nuclei. The most advanced recombinant Ads lack all adenoviral genes. This renders these so-called high-capacity (hc) Ad vectors less cytotoxic/immunogenic than those only deleted in early regions and creates space for the insertion of large/multiple transgenes. The versatility of hcAd vectors is been increased by capsid modifications to alter their tropism and by the incorporation into their genomes of sequences promoting chromosomal insertion of exogenous DNA. Adeno-associated virus (AAV) can insert its genome into a specific human locus designated AAVS1. Trans- and cis-acting elements needed for this reaction are the AAV Rep78/68 proteins and Rep78/68-binding sequences, respectively. Here, we describe the generation, characterization and testing of fiber-modified dual hcAd/AAV hybrid vectors (dHVs) containing both these elements. Due to the inhibitory effects of Rep78/68 on Ad-dependent DNA replication, we deployed a recombinase-inducible gene switch to repress Rep68 synthesis during vector rescue and propagation. Flow cytometric analyses revealed that rep68-positive dHVs can be produced similarly well as rep68-negative control vectors. Western blot experiments and immunofluorescence microscopy analyses demonstrated transfer of recombinase-dependent rep68 genes into target cells. Studies in HeLa cells and in the dystrophin-deficient myoblasts from a Duchenne muscular dystrophy (DMD) patient showed that induction of Rep68 synthesis in cells transduced with fiber-modified and rep68-positive dHVs leads to increased stable transduction levels and AAVS1-targeted integration of vector DNA. These results warrant further investigation especially considering the paucity of vector systems allowing permanent phenotypic correction of patient-own cell types with large DNA (e.g. recombinant full-length DMD genes).
Human Embryonic and Fetal Mesenchymal Stem Cells Differentiate toward Three Different Cardiac Lineages in Contrast to Their Adult Counterparts
Arti A. Ramkisoensing, Dani?l A. Pijnappels, Sa?d F. A. Askar, Robert Passier, Jim Swildens, Marie José Goumans, Cindy I. Schutte, Antoine A. F. de Vries, Sicco Scherjon, Christine L. Mummery, Martin J. Schalij, Douwe E. Atsma
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024164
Abstract: Mesenchymal stem cells (MSCs) show unexplained differences in differentiation potential. In this study, differentiation of human (h) MSCs derived from embryonic, fetal and adult sources toward cardiomyocytes, endothelial and smooth muscle cells was investigated. Labeled hMSCs derived from embryonic stem cells (hESC-MSCs), fetal umbilical cord, bone marrow, amniotic membrane and adult bone marrow and adipose tissue were co-cultured with neonatal rat cardiomyocytes (nrCMCs) or cardiac fibroblasts (nrCFBs) for 10 days, and also cultured under angiogenic conditions. Cardiomyogenesis was assessed by human-specific immunocytological analysis, whole-cell current-clamp recordings, human-specific qRT-PCR and optical mapping. After co-culture with nrCMCs, significantly more hESC-MSCs than fetal hMSCs stained positive for α-actinin, whereas adult hMSCs stained negative. Furthermore, functional cardiomyogenic differentiation, based on action potential recordings, was shown to occur, but not in adult hMSCs. Of all sources, hESC-MSCs expressed most cardiac-specific genes. hESC-MSCs and fetal hMSCs contained significantly higher basal levels of connexin43 than adult hMSCs and co-culture with nrCMCs increased expression. After co-culture with nrCFBs, hESC-MSCs and fetal hMSCs did not express α-actinin and connexin43 expression was decreased. Conduction velocity (CV) in co-cultures of nrCMCs and hESC-MSCs was significantly higher than in co-cultures with fetal or adult hMSCs. In angiogenesis bioassays, only hESC-MSCs and fetal hMSCs were able to form capillary-like structures, which stained for smooth muscle and endothelial cell markers.Human embryonic and fetal MSCs differentiate toward three different cardiac lineages, in contrast to adult MSCs. Cardiomyogenesis is determined by stimuli from the cellular microenvironment, where connexin43 may play an important role.
Exploitation of Herpesvirus Immune Evasion Strategies to Modify the Immunogenicity of Human Mesenchymal Stem Cell Transplants
Anabel S. de la Garza-Rodea,Marieke C. Verweij,Hester Boersma,Ietje van der Velde-van Dijke,Antoine A. F. de Vries,Rob C. Hoeben,Dirk W. van Bekkum,Emmanuel J. H. J. Wiertz,Shoshan Kna?n-Shanzer
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0014493
Abstract: Mesenchymal stem cells (MSCs) are multipotent cells residing in the connective tissue of many organs and holding great potential for tissue repair. In culture, human MSCs (hMSCs) are capable of extensive proliferation without showing chromosomal aberrations. Large numbers of hMSCs can thus be acquired from small samples of easily obtainable tissues like fat and bone marrow. MSCs can contribute to regeneration indirectly by secretion of cytokines or directly by differentiation into specialized cell types. The latter mechanism requires their long-term acceptance by the recipient. Although MSCs do not elicit immune responses in vitro, animal studies have revealed that allogeneic and xenogeneic MSCs are rejected.
Radiopharmaceuticals for imaging chronic lymphocytic inflammation
Malviya, Gaurav;Vries, Erik F.J. de;Dierckx, Rudi A.;Signore, Alberto;
Brazilian Archives of Biology and Technology , 2007, DOI: 10.1590/S1516-89132007000600002
Abstract: in the last few decades, a number of radiopharmaceuticals for imaging inflammation have been proposed that differ in their specificity and mechanism of uptake in inflamed foci as compared to the traditional inflammation imaging agents. radiolabelled cytokines represent a reliable tool for the preclinical diagnosis of chronic inflammatory processes, even before anatomical and functional changes occur in affected tissues. moreover, the introduction of radiolabelled monoclonal antibodies and sophisticated technique like pet/ct now make the field of inflammation imaging highly specific and accurate. in this review, different approaches of the established and experimental radiopharmaceuticals for imaging of chronic inflammation are discussed.
Psychometric properties of the Fatigue Assessment Scale (FAS) in women with breast problems
Jolanda De Vries,Alida F. Van der Steeg,Jan A. Roukema
International Journal of Clinical and Health Psychology , 2010,
Abstract: Se examina la utilidad de la Escala de Evaluación de la Fatiga (FAS) en mujeres con problemas benignos de mama (BBP) y en mujeres con cáncer precoz de mama (BC). Las mujeres con un nódulo palpable en la mama o una anomalía en unamamografía de cribado (N = 560) completaron la FAS (en cuatro momentos) y medidas de ansiedad, síntomas depresivos, neuroticismo, y fatiga. La FAS tuvo un buen ajuste en la población total (CFI = 0,96; ×2 (29) = 104,5, p < 0,001; NNFI = 0,95; RMSEA = 0,091), en el grupo de BC (CFI = 0,95; X2 (32) = 69,6, p < 0,001; NNFI = 0,91; RMSEA = 0,090) y en el grupo BBP (CFI = 0,95; ×2 (34) = 99,9, p < 0,001; NNFI = 0,92; RMSEA = 0,105). La consistencia interna (0,89 para el grupo total) y la fiabilidad test-retest (grupo BBP, r = 0,88 intervalo de tres meses) fueron buenas. La FAS diferenció síntomas depresivos, neuroticismo, estado de ansiedad. En conclusión, la FAS tiene una buena fiabilidad y validez en mujeres con problemas de mama y mide fatiga sin superponerse de forma importante con síntomas depresivos, estado de ansiedad y neuroticismo.
Early Neurological Outcome of Young Infants Exposed to Selective Serotonin Reuptake Inhibitors during Pregnancy: Results from the Observational SMOK Study
Nathalie K. S. de Vries, Christine N. van der Veere, Sijmen A. Reijneveld, Arend F. Bos
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064654
Abstract: Background Use of selective serotonin reuptake inhibitors (SSRI) during pregnancy is common while the effect on the infant’s neurological outcome is unknown. Our objective was to determine the effects of prenatal SSRI-exposure on the infants’ neurological functioning, adjusted for maternal mental health. Methods A prospective observational study from May 2007 to April 2010. The study groups comprised 63 SSRI-exposed infants (SSRI group) and 44 non-exposed infants (non-SSRI group). Maternal depression and anxiety were measured using questionnaires. The main outcome measures during the first week after birth and at three to four months were the quality of the infants’ general movements (GMs) according to Prechtl and a detailed motor optimality score. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for abnormal GM quality in the SSRI and non-SSRI groups, and adjusted for maternal depression, anxiety, and other confounders. The study was registered under 53506435 in the ISRCTN. Findings All infants were born around term. During the first week, abnormal GMs occurred more frequently in the SSRI group than in the non-SSRI group (59% versus 33%) and the median MOS was lower (13 versus 18). The OR for abnormal GMs in the SSRI versus the non-SSRI group was 3·0 (95% CI, 1.3 to 6.9) and increased after adjustment for confounders. At three to four months, more SSRI-exposed infants had monotonous movements (48% versus 20%) with lower median MOSs (26 versus 28). The OR for monotonous movements was 3·5 (95% CI, 1.5 to 8.6) and increased after adjusting for confounders. Interpretation Prenatal exposure to SSRI had an adverse effect on early neurological functioning as reflected by GM quality, irrespective of maternal depression and anxiety, and other confounders. Physicians should take this into account in consultation with parents.
The End of the CMSSM Coannihilation Strip is Nigh
M. Citron,J. Ellis,F. Luo,J. Marrouche,K. A. Olive,K. J. de Vries
Physics , 2012, DOI: 10.1103/PhysRevD.87.036012
Abstract: A recent global fit to the CMSSM incorporating current constraints on supersymmetry, including missing transverse energy searches at the LHC, BR(B_s to mu+ mu-) and the direct XENON100 search for dark matter, favours points towards the end of the stau-neutralino (stau_1- chi) coannihilation strip with relatively large m_1/2 and 10 < tan beta < 40 and points in the H/A rapid-annihilation funnel with tan beta ~ 50. The coannihilation points typically have m_stau_1-m_chi < 5 GeV, and a significant fraction, including the most-favoured point, has m_stau_1-m_chi < m_tau. In such a case, the stau_1 lifetime would be so long that the stau_1 would be detectable as a long-lived massive charged particle that may decay inside or outside the apparatus. We show that CMSSM scenarios close to the tip of the coannihilation strip for tan beta < 40 are already excluded by LHC searches for massive charged particles, and discuss the prospects for their detection in the CMS and ATLAS detectors via time-of-flight measurements, anomalous heavy ionization or decays into one or more soft charged particles.
17O NMR study of the intrinsic magnetic susceptibility and spin dynamics of the quantum kagome antiferromagnet ZnCu3(OH)6Cl2
A. Olariu,P. Mendels,F. Bert,F. Duc,J. C. Trombe,M. A. de Vries,A. Harrisson
Physics , 2007, DOI: 10.1103/PhysRevLett.100.087202
Abstract: We report through 17O NMR, an unambiguous local determination of the intrinsic kagome lattice spin susceptibility as well as that created around non-magnetic defects issued from natural Zn/ Cu exchange in the S=1/2 (Cu2+) herbertsmithite ZnCu3(OH)6Cl2 compound. The issue of a singlet-triplet gap is addressed. The magnetic response around a defect is found to markedly differ from that observed in non-frustrated antiferromagnetic materials. Finally, we discuss our relaxation measurements in the light of Cu and Cl NMR data [cond-mat 070314] and suggest a flat q-dependence of the excitations.
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