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Träfflista för sökning "WFRF:(Brock Roland) "

Search: WFRF:(Brock Roland)

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1.
  • Aad, G, et al. (author)
  • 2015
  • swepub:Mat__t
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2.
  • Aaron, F. D., et al. (author)
  • Combined measurement and QCD analysis of the inclusive e(+/-)p scattering cross sections at HERA
  • 2010
  • In: Journal of High Energy Physics. - 1029-8479. ; :1
  • Journal article (peer-reviewed)abstract
    • A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e(+/-)p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q(2), and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.
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3.
  • Aaron, F. D., et al. (author)
  • Events with an isolated lepton and missing transverse momentum and measurement of W production at HERA
  • 2010
  • In: Journal of High Energy Physics. - 1029-8479. ; 2010:3, s. 1-19
  • Journal article (peer-reviewed)abstract
    • A search for events containing an isolated electron or muon and missing trans verse momentum produced in e(+/-)p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb(-1). The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e(+)p data, at large hadronic transverse momentum P-T(X) > 25GeV, a total of 23 events are observed compared to a prediction of 14.0 +/- 1.9. The total single W boson production cross section is measured as 1.06 +/- 0.16 (stat.) +/- 0.07 (sys.) pb, in agreement with an Standard Model (SM) expectation of 1.26 +/- 0.19 pb.
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4.
  • Aaron, F. D., et al. (author)
  • Multi-leptons with high transverse momentum at HERA
  • 2009
  • In: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :10
  • Journal article (peer-reviewed)abstract
    • Events with at least two high transverse momentum leptons (electrons or muons) are studied using the H1 and ZEUS detectors at HERA with an integrated luminosity of 0.94 fb(-1). The observed numbers of events are in general agreement with the Standard Model predictions. Seven di- and tri-lepton events are observed in e(+)p collision data with a scalar sum of the lepton transverse momenta above 100 GeV while 1.94 +/- 0.17 events are expected. Such events are not observed in e(-)p collisions for which 1.19 +/- 0.12 are predicted. Total visible and differential di-electron and di-muon photoproduction cross sections are extracted in a restricted phase space dominated by photon-photon collisions.
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5.
  • Holm, Tina, 1979- (author)
  • Cell-penetrating peptides : Uptake, stability and biological activity
  • 2011
  • Doctoral thesis (other academic/artistic)abstract
    • Cell-penetrating peptides (CPPs) have emerged as a group of remarkable delivery vectors for various hydrophilic macromolecules, otherwise excluded from cells due to the protective plasma membrane. Unbiased conclusions regarding e.g. uptake mechanism, intracellular distribution and cargo delivery efficacy is complicated by the use of different methodological parameters by different laboratories. The first paper in this thesis introduced unifying protocols enabling comparison of results from different research groups. One of these methods, HPLC, was used in paper II to investigate CPP uptake and degradation in yeasts. Both parameters varied depending on peptide and yeast species; however pVEC emerged as a promising delivery vector in yeast since it internalized into both species tested without concomitant degradation. Protein mimicry was another investigated phenomenon and in paper III a 22-mer peptide from the p14Arf protein (Arf (1-22)) was found to be sufficient for retaining its function as a tumor suppressor. This peptide comprised a combination of apoptogenic property and CPP in one unity, thus providing opportunity to conjugate cytotoxic agents boosting the tumoricidal activity. Surprisingly, a partially inverted control peptide to Arf (1-22), called M918, was found to be an extraordinary CPP. In paper IV, it was shown to be superior to well-established CPPs in delivery of both peptide nucleic acids and proteins. Albeit the promising results these two peptides displayed, their utility in vivo, as with all peptides, is hampered by rapid degradation. With the aim of improving their stability, Arf (1-22) and M918 were synthesized with D-amino acids in the reverse order, a modification called retro-inverso (RI) isomerization. Their cell-penetrating ability was retained, but the treated cells displayed unexpected morphological alterations indicative of apoptosis. The presented results demonstrate the versatility of CPPs, functioning as vectors in both yeast and mammalian cells and as protein mimicking peptides with biological activity. Their potential as drug delivery agents is obvious; however, peptide degradation is an issue that requires further improvements before clinical success is in reach.
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6.
  • Myrberg, Helena, 1979- (author)
  • Cell-penetrating peptides in cargo delivery : In vitro studies on uptake and in vivo studies on tumor targeting
  • 2008
  • Doctoral thesis (other academic/artistic)abstract
    • The capability of cell-penetrating peptides (CPPs) to transport cargos over different cellular membranes both in vitro and in vivo have drawn major attention in the past decade. Three main topics on the application of CPPs have been studied in this thesis.First, several well-known CPPs, with fluorescein as a cargo, were shown to translocate into Nicotiana tabacum cultivar SR-1 protoplasts. By coupling different cargos to CPP it might be possible to effectively transport them inside the plant protoplasts. The translocation of CPPs into plant protoplasts might open up a new method for transformation of plant cells.Next, the cell-penetrating ability of the novel peptide YTA2 was characterized and it was established that chemical coupling between YTA2 and the protein cargo is not needed for the transport of the cargo over the cellular membrane in vitro. The delivery of proteins into cells by mere coincubation with CPPs is an improvement, since the chemical coupling between the CPP and the cargo molecule, which adds time-consuming synthesis and purification steps, can be omitted.Finally, by conjugating each of the two breast tumor homing peptides, the cyclic cCPGPEGAGC (PEGA) or the linear CREKA peptide, to the CPP pVEC, two cell-penetrating peptides with homing properties were obtained. Both, PEGA-pVEC and CREKA-pVEC were taken up by different breast cancer cells in vitro. Moreover, the homing capacity of the PEGA-pVEC and CREKA-pVEC was conserved in vivo, where the conjugates mainly accumulated in blood vessels in breast tumor tissue and were subsequently translocated into cells. Conjugating the anti-cancer drug chlorambucil to PEGA-pVEC or CREKA-pVEC markedly improved its efficiency. Furthermore, systemic treatment of tumor-bearing mice with chlorambucil-CREKA-pVEC significantly reduced tumor growth compared to control groups. These tumor-homing CPPs might improve both diagnosis and treatment of breast cancer tumors, by conjugation to therapeutic agents.
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7.
  • Palacio-Castaneda, Valentina, et al. (author)
  • Mimicking the Biology of Engineered Protein and mRNA Nanoparticle Delivery Using a Versatile Microfluidic Platform
  • 2021
  • In: Pharmaceutics. - : MDPI AG. - 1999-4923 .- 1999-4923. ; 13:11, s. 1944-
  • Journal article (peer-reviewed)abstract
    • To investigate the delivery of next-generation macromolecular drugs, such as engineered proteins and mRNA-containing nanoparticles, there is an increasing push towards the use of physiologically relevant disease models that incorporate human cells and do not face ethical dilemmas associated with animal use. Here, we illustrate the versatility and ease of use of a microfluidic platform for studying drug delivery using high-resolution microscopy in 3D. Using this microfluidic platform, we successfully demonstrate the specific targeting of carbonic anhydrase IX (CAIX) on cells overexpressing the protein in a tumor-mimicking chip system using affibodies, with CAIX-negative cells and non-binding affibodies as controls. Furthermore, we demonstrate this system's feasibility for testing mRNA-containing biomaterials designed to regenerate bone defects. To this end, peptide-and lipid-based mRNA formulations were successfully mixed with colloidal gelatin in microfluidic devices, while translational activity was studied by the expression of a green fluorescent protein. This microfluidic platform enables the testing of mRNA delivery from colloidal biomaterials of relatively high densities, which represents a first important step towards a bone-on-a-chip platform. Collectively, by illustrating the ease of adaptation of our microfluidic platform towards use in distinct applications, we show that our microfluidic chip represents a powerful and flexible way to investigate drug delivery in 3D disease-mimicking culture systems that recapitulate key parameters associated with in vivo drug application.
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8.
  • van Asbeck, Alexander H., et al. (author)
  • Molecular Parameters of siRNA-Cell Penetrating Peptide Nanocomplexes for Efficient Cellular Delivery
  • 2013
  • In: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 7:5, s. 3797-3807
  • Journal article (peer-reviewed)abstract
    • Cell-penetrating peptides (CPPs) are versatile tools for the intracellular delivery of various biomolecules, including siRNA. Recently, CPPs were introduced that showed greatly enhanced delivery efficiency. However, the molecular basis of this increased activity is poorly understood. Here, we performed a detailed analysis of the molecular and physicochemical properties of seven different siRNA-CPP nanoparticles. In addition, we determined which complexes are internalized most efficiently into the leukemia cell-line SKNO-1, and subsequently inhibited the expression of a luctferase reporter gene. We demonstrated effective complexation of siRNA for all tested CPPs, and optimal encapsulation of the siRNA was achieved at very similar molar ratios independent of peptide charge. However, CPPs with an extreme high or low overall charge proved to be exceptions, suggesting an optimal range of charge for CPP-siRNA nanoparticle formation based on opposite charge. The most active CPP (PepFect6) displayed high serum resistance but also high sensitivity to decomplexation by polyanionic macromolecules, indicating the necessity for partial decomplexation for efficient uptake. Surprisingly, CPP-siRNA complexes acquired a negative zeta-potential in the presence of serum. These novel insights shed light on the observation that cell association is necessary but not sufficient for activity and motivate new research into the nature of the nanoparticle-cell interaction. Overall, our results provide a comprehensive molecular basis for the further development of peptide-based olipnudeotide transfection agents.
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9.
  • van den Brand, Dirk, et al. (author)
  • Peptide-mediated delivery of therapeutic mRNA in ovarian cancer
  • 2019
  • In: European journal of pharmaceutics and biopharmaceutics. - : Elsevier BV. - 0939-6411 .- 1873-3441. ; 141, s. 180-190
  • Journal article (peer-reviewed)abstract
    • Ovarian cancer is the most lethal gynecological malignancy in the developed world. In spite of intensive research, the mortality has hardly decreased over the past twenty years. This necessitates the exploration of novel therapeutic modalities. Transient protein expression through delivery of mRNA is emerging as a highly promising option. In contrast to gene therapy there is no risk of integration into the genome. Here, we explore the expression of mRNA in models of ovarian cancer of increasing complexity. The cell-penetrating peptide (CPP) PepFect 14 (PF14) was used to formulate CPP-mRNA nanoparticles. Efficient expression of a reporter protein was achieved in two-dimensional tissue cultures and in three-dimensional cancer cell spheroids. PF14 nano particles greatly outperformed a lipid-based transfection agent in vivo, leading to expression in various cell types of tumor associated tissue. Protein expression was restricted to the peritoneal cavity. Messenger RNA expression across different cell types was confirmed in primary ovarian cancer explants. As ovarian cancer is confined to the peritoneal cavity in most cases, the results create the basis for applications in which the tumor microenviron-ment is transiently modified through protein expression.
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10.
  • van der Bent, M. Leontien, et al. (author)
  • The nuclear concentration required for antisense oligonucleotide activity in myotonic dystrophy cells
  • 2019
  • In: The FASEB Journal. - 0892-6638 .- 1530-6860. ; 33:10, s. 11314-11325
  • Journal article (peer-reviewed)abstract
    • Antisense oligonucleotides (ASOs) are a promising class of therapeutics that are starting to emerge in the clinic. Determination of intracellular concentrations required for biologic effects and identification of effective delivery vehicles are crucial for understanding the mode of action and required dosing. Here, we investigated which nuclear oligonucleotide concentration is needed for a therapeutic effect for a triplet repeat-targeting ASO in a muscle cell model of myotonic dystrophy type 1 (DM1). For cellular delivery, ASOs were complexed into nanoparticles using the cationic cell-penetrating peptides nona-arginine and PepFect14 (PF14). Although both peptides facilitated uptake, only PF14 led to a dose-dependent correction of disease-typical abnormal splicing. In line with this observation, time-lapse confocal microscopy demonstrated that only PF14 mediated translocation of the ASOs to the nucleus, which is the main site of action. Through fluorescence lifetime imaging, we could distinguish intact oligonucleotide from free fluorophore, showing that PF14 also shielded the ASOs from degradation. Finally, we employed a combination of live-cell fluorescence correlation spectroscopy and immunofluorescence microscopy and demonstrated that intranuclear blocking-type oligonucleotide concentrations in the upper nanomolar range were required to dissolve nuclear muscleblind-like protein 1 foci, a hallmark of DM1. Our findings have important implications for the clinical use of ASOs in DM1 and provide a basis for further research on other types of ASOs.-Van der Bent, M. L., Paulino da Silva Filho, O., Willemse, M., Hallbrink, M., Wansink, D. G., Brock, R. The nuclear concentration required for antisense oligonucleotide activity in myotonic dystrophy cells.
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