Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 276 )

2018 ( 597 )

2017 ( 591 )

2016 ( 706 )

Custom range...

Search Results: 1 - 10 of 328241 matches for " Helga E de Vries "
All listed articles are free for downloading (OA Articles)
Page 1 /328241
Display every page Item
The Role of ATP-Binding Cassette Transporters in Neuro-Inflammation: Relevance for Bioactive Lipids
Gijs Kooij,Jack van Horssen,Veera Venkata Ratnam Bandaru,Helga E. de Vries
Frontiers in Pharmacology , 2012, DOI: 10.3389/fphar.2012.00074
Abstract: ATP-binding cassette (ABC) transporters are highly expressed by brain endothelial cells that form the blood–brain barrier (BBB). These efflux pumps play an important role in maintaining brain homeostasis as they actively hinder the entry of unwanted blood-derived compounds into the central nervous system (CNS). Consequently, their high activity at the BBB has been a major hurdle for the treatment of several brain diseases, as they prevent numerous drugs to reach their site of action within the brain. Importantly, recent data indicate that endogenous substrates for ABC transporters may include inflammatory mediators, such as prostaglandins, leukotrienes, cytokines, chemokines, and bioactive lipids, suggesting a potential role for ABC transporters in immunological responses, and more specifically in inflammatory brain disorders, such as multiple sclerosis (MS). In this review, we will give a comprehensive overview of recent findings that illustrate this novel role for ABC transporters in neuro-inflammatory processes. Moreover, we will provide first insights into underlying mechanisms and focus on the importance for bioactive lipids, in particular platelet-activating factor, herein. A thorough understanding of these events may form the basis for the development for selective treatment modalities to dampen the neuro-inflammatory attack in MS and thereby reducing tissue damage.
P-Glycoprotein Acts as an Immunomodulator during Neuroinflammation
Gijs Kooij,Ronald Backer,Jasper J. Koning,Arie Reijerkerk,Jack van Horssen,Susanne M. A. van der Pol,Joost Drexhage,Alfred Schinkel,Christine D. Dijkstra,Joke M. M. den Haan,Teunis B. H. Geijtenbeek,Helga E. de Vries
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0008212
Abstract: Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system in which autoreactive myelin-specific T cells cause extensive tissue damage, resulting in neurological deficits. In the disease process, T cells are primed in the periphery by antigen presenting dendritic cells (DCs). DCs are considered to be crucial regulators of specific immune responses and molecules or proteins that regulate DC function are therefore under extensive investigation. We here investigated the potential immunomodulatory capacity of the ATP binding cassette transporter P-glycoprotein (P-gp). P-gp generally drives cellular efflux of a variety of compounds and is thought to be involved in excretion of inflammatory agents from immune cells, like DCs. So far, the immunomodulatory role of these ABC transporters is unknown.
Pharmacokinetics, Brain Delivery, and Efficacy in Brain Tumor-Bearing Mice of Glutathione Pegylated Liposomal Doxorubicin (2B3-101)
Pieter J. Gaillard, Chantal C. M. Appeldoorn, Rick Dorland, Joan van Kregten, Francesca Manca, Danielle J. Vugts, Bert Windhorst, Guus A. M. S. van Dongen, Helga E. de Vries, David Maussang, Olaf van Tellingen
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0082331
Abstract: Brain cancer is a devastating disease affecting many people worldwide. Effective treatment with chemotherapeutics is limited due to the presence of the blood-brain barrier (BBB) that tightly regulates the diffusion of endogenous molecules but also xenobiotics. Glutathione pegylated liposomal doxorubicin (2B3-101) is being developed as a new treatment option for patients with brain cancer. It is based on already marketed pegylated liposomal doxorubicin (Doxil?/Caelyx?), with an additional glutathione coating that safely enhances drug delivery across the BBB. Uptake of 2B3-101 by human brain capillary endothelial cells in vitro was time-, concentration- and temperature-dependent, while pegylated liposomal doxorubicin mainly remained bound to the cells. In vivo, 2B3-101 and pegylated liposomal doxorubicin had a comparable plasma exposure in mice, yet brain retention 4 days after administration was higher for 2B3-101. 2B3-101 was overall well tolerated by athymic FVB mice with experimental human glioblastoma (luciferase transfected U87MG). In 2 independent experiments a strong inhibition of brain tumor growth was observed for 2B3-101 as measured by bioluminescence intensity. The effect of weekly administration of 5 mg/kg 2B3-101 was more pronounced compared to pegylated liposomal doxorubicin (p<0.05) and saline (p<0.01). Two out of 9 animals receiving 2B3-101 showed a complete tumor regression. Twice-weekly injections of 5 mg/kg 2B3-101 again had a significant effect in inhibiting brain tumor growth (p<0.001) compared to pegylated liposomal doxorubicin and saline, and a complete regression was observed in 1 animal treated with 2B3-101. In addition, twice-weekly dosing of 2B3-101 significantly increased the median survival time by 38.5% (p<0.001) and 16.1% (p<0.05) compared to saline and pegylated liposomal doxorubicin, respectively. Overall, these data demonstrate that glutathione pegylated liposomal doxorubicin enhances the effective delivery of doxorubicin to brain tumors and could become a promising new therapeutic option for the treatment of brain malignancies.
Clusters of activated microglia in normal-appearing white matter show signs of innate immune activation
Jack van Horssen, Shailender Singh, Susanne van der Pol, Markus Kipp, Jamie L Lim, Laura Peferoen, Wouter Gerritsen, Evert-Jan Kooi, Maarten E Witte, Jeroen J Geurts, Helga E de Vries, Regina Peferoen-Baert, Peter J van den Elsen, Paul van der Valk, Sandra Amor
Journal of Neuroinflammation , 2012, DOI: 10.1186/1742-2094-9-156
Abstract: Here, we document the frequency of preactive lesions and their association with distinct white matter lesions in a cohort of 21 MS patients. Immunohistochemistry was used to gain further insight into the cellular and molecular composition of preactive lesions.Preactive lesions were observed in a majority of MS patients (67%) irrespective of disease duration, gender or subtype of disease. Microglial clusters were predominantly observed in the vicinity of active demyelinating lesions and are not associated with T cell infiltrates, axonal alterations, activated astrocytes or blood–brain barrier disruption. Microglia in preactive lesions consistently express interleukin-10 and TNF-α, but not interleukin-4, whereas matrix metalloproteases-2 and ?9 are virtually absent in microglial nodules. Interestingly, key subunits of the free-radical-generating enzyme NADPH oxidase-2 were abundantly expressed in microglial clusters.The high frequency of preactive lesions suggests that it is unlikely that most of them will progress into full-blown demyelinating lesions. Preactive lesions are not associated with blood–brain barrier disruption, suggesting that an intrinsic trigger of innate immune activation, rather than extrinsic factors crossing a damaged blood–brain barrier, induces the formation of clusters of activated microglia.
Sphingosine 1-phosphate receptor 5 mediates the immune quiescence of the human brain endothelial barrier
Ruben van Doorn, Melissa A Lopes Pinheiro, Gijs Kooij, Kim Lakeman, Bert van het Hof, Susanne MA van der Pol, Dirk Geerts, Jack van Horssen, Paul van der Valk, Elizabeth van der Kam, Eric Ronken, Arie Reijerkerk, Helga E de Vries
Journal of Neuroinflammation , 2012, DOI: 10.1186/1742-2094-9-133
Abstract: We analyzed the expression of S1P5 in human post-mortem tissues using immunohistochemistry. The function of S1P5 at the BBB was assessed in cultured human brain endothelial cells (ECs) using agonists and lentivirus-mediated knockdown of S1P5. Subsequent analyses of different aspects of the brain EC barrier included the formation of a tight barrier, the expression of BBB proteins and markers of inflammation and monocyte transmigration.We show that activation of S1P5 on cultured human brain ECs by a selective agonist elicits enhanced barrier integrity and reduced transendothelial migration of monocytes in vitro. These results were corroborated by genetically silencing S1P5 in brain ECs. Interestingly, functional studies with these cells revealed that S1P5 strongly contributes to brain EC barrier function and underlies the expression of specific BBB endothelial characteristics such as tight junctions and permeability. In addition, S1P5 maintains the immunoquiescent state of brain ECs with low expression levels of leukocyte adhesion molecules and inflammatory chemokines and cytokines through lowering the activation of the transcription factor NFκB.Our findings demonstrate that S1P5 in brain ECs contributes to optimal barrier formation and maintenance of immune quiescence of the barrier endothelium.
Diabetes in Africa: the new pandemic. Report on the 19th World Diabetes Congress, Cape Town, December 2006
B Mash, E de Vries, I Abdul
South African Family Practice , 2007,
Abstract: The prevalence of diabetes in Africa is predicted to increase by 80% in 2025 and impact younger working age patients. We increasingly live in an obesogenic society that drives the global pandemic of Type 2 diabetes. The powerful commercial, socio-economic and political factors shaping this society encourage individual choices that lead to a sedentary and unhealthy lifestyle. These factors are increasingly seen in lower income countries. The metabolic syndrome is now an established entity which can be identified and treated prior to the development of diabetes. In sub-Saharan Africa there is an emerging relationship between the HIV and diabetic epidemics. For example HAART leads to a higher risk of diabetes and diabetes increases the risk of infections such as TB. The quality of care in sub-Saharan Africa can be improved with relatively simple measures if they are implemented consistently and guidelines have been developed for this context. A vision for the way forward in Africa has been expressed in the 2006 African Diabetes Declaration. South African Family Practice Vol. 49 (6) 2007: pp. 44-50
Aspecific complaints of a gastrostomy feeding tube caused by Group A Streptococcus.
Tjalling W. de Vries,Tina E. Faber
Gastroenterology Insights , 2009, DOI: 10.4081/gi.2009.e1
Abstract: A seven-year old girl with a gastrostomy feeding tube presented with aspecific symptoms such as discomfort and a foul smell. No cause could be found but a culture revealed Group A Streptococcus. These were eradicated by antibiotic treatment and the symptoms resolved immediately. In patients with a gastrostomy feeding tube presenting with aspecific complaints for which a cause can not be found, a culture for Group A Streptococcus should be obtained.
Physical properties of amorphous solid interstellar material from X-ray absorption spectroscopy of Sco X-1
C. P. de Vries E. Costantini
Physics , 2009,
Abstract: High quality, high resolution X-ray spectra were obtained of Sco X-1 with the Reflection Grating Spectrometer (RGS) on board the XMM-Newton satellite. The spectrum around the Oxygen K-edge is searched for signatures indicative for EXAFS. Analysis shows a clear indication for the existence of EXAFS with photo-electron scattering distances in the absorbing medium in a range which applies to many solids. When scattering of the photo-electron on Oxygen atoms is assumed, the Oxygen to Oxygen atom distances found are 2.75 Angstrom. This fits with distances as found in amorphous water-ice, although water ice is thought to be an unlikely constituent of the diffuse interstellar clouds which form the absorbing medium towards Sco X-1
Profile Matching in Electronic Social Networks Using a Matching Measure for Fuzzy Numerical Attributes and Fields of Interests  [PDF]
Andreas de Vries
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.516250
Abstract: The problem of profile matching in electronic social networks asks to find those offering profiles of actors in the network fitting best to a given search profile. In this article this problem is mathematically formulated as an optimization problem. For this purpose the underlying search space and the objective function are defined precisely. In particular, data structures of search and offering profiles are proposed, as well as a function measuring the matching of the attributes of a search profile with the corresponding attributes of an offering profile. This objective function, given in Equation (29), is composed of the partial matching degrees for numerical attributes, discrete non-numerical attributes, and fields of interests, respectively. For the matching degree of numerical profile attributes a fuzzy value approach is presented, see Equation (22), whereas for the matching degree of fields of interest a new measure function is introduced in Equation (26). The resulting algorithm is illustrated by a concrete example. It not only is applicable to electronic social networks but also could be adapted for resource discovery in grid computation or in matchmaking energy demand and supply in electrical power systems and smart grids, especially to efficiently integrate renewable energy resources.
Correction: Retinal Ganglion Cells Can Rapidly Change Polarity from Off to On
Maria Neimark Geffen,Saskia E. J. de Vries,Markus Meister
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0050136
Page 1 /328241
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.