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Search Results: 1 - 10 of 297800 matches for " Anink Jasper J "
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Differential expression of major histocompatibility complex class I in developmental glioneuronal lesions
Prabowo Avanita S,Iyer Anand M,Anink Jasper J,Spliet Wim GM
Journal of Neuroinflammation , 2013, DOI: 10.1186/1742-2094-10-12
Abstract: Purpose The expression of the major histocompatibility complex class I (MHC-I) in the brain has received considerable interest not only because of its fundamental role in the immune system, but also for its non-immune functions in the context of activity-dependent brain development and plasticity. Methods In the present study we evaluated the expression and cellular pattern of MHC-I in focal glioneuronal lesions associated with intractable epilepsy. MHC-I expression was studied in epilepsy surgery cases with focal cortical dysplasia (FCD I, n = 6; FCD IIa, n = 6 and FCD IIb, n = 15), tuberous sclerosis complex (TSC, cortical tubers; n = 6) or ganglioglioma (GG; n = 15) using immunocytochemistry. Evaluation of T lymphocytes with granzyme-B+ granules and albumin immunoreactivity was also performed. Results All lesions were characterized by MHC-I expression in blood vessels. Expression in both endothelial and microglial cells as well as in neurons (dysmorphic/dysplastic neurons) was observed in FCD II, TSC and GG cases. We observed perivascular and parenchymal T lymphocytes (CD8+, T-cytotoxic) with granzyme-B+ granules in FCD IIb and TSC specimens. Albumin extravasation, with uptake in astrocytes, was observed in FCD IIb and GG cases. Conclusions Our findings indicate a prominent upregulation of MHC-I as part of the immune response occurring in epileptogenic glioneuronal lesions. In particular, the induction of MHC-I in neuronal cells appears to be a feature of type II FCD, TSC and GG and may represent an important accompanying event of the immune response, associated with blood–brain barrier dysfunction, in these developmental lesions.
Regulation of Kir4.1 expression in astrocytes and astrocytic tumors: a role for interleukin-1 β
Zurolo Emanuele,de Groot Marjolein,Iyer Anand,Anink Jasper
Journal of Neuroinflammation , 2012, DOI: 10.1186/1742-2094-9-280
Abstract: Objective Decreased expression of inwardly rectifying potassium (Kir) channels in astrocytes and glioma cells may contribute to impaired K+ buffering and increased propensity for seizures. Here, we evaluated the potential effect of inflammatory molecules, such as interleukin-1β (IL-1β) on Kir4.1 mRNA and protein expression. Methods We investigated Kir4.1 (Kcnj10) and IL-1β mRNA expression in the temporal cortex in a rat model of temporal lobe epilepsy 24 h and 1 week after induction of status epilepticus (SE), using real-time PCR and western blot analysis. The U373 glioblastoma cell line and human fetal astrocytes were used to study the regulation of Kir4.1 expression in response to pro-inflammatory cytokines. Expression of Kir4.1 protein was also evaluated by means of immunohistochemistry in surgical specimens of patients with astrocytic tumors (n = 64), comparing the expression in tumor patients with (n = 38) and without epilepsy (n = 26). Results Twenty-four hours after onset of SE, Kir4.1 mRNA and protein were significantly down-regulated in temporal cortex of epileptic rats. This decrease in expression was followed by a return to control level at 1 week after SE. The transient downregulation of Kir4.1 corresponded to the time of prominent upregulation of IL-1β mRNA. Expression of Kir4.1 mRNA and protein in glial cells in culture was downregulated after exposure to IL-1β. Evaluation of Kir4.1 in tumor specimens showed a significantly lower Kir4.1 expression in the specimens of patients with epilepsy compared to patients without epilepsy. This paralleled the increased presence of activated microglial cells, as well as the increased expression of IL-1β and the cytoplasmic translocation of high mobility group box 1 (HMGB1). Conclusions Taken together, these findings indicate that alterations in expression of Kir4.1 occurring in epilepsy-associated lesions are possibly influenced by the local inflammatory environment and in particular by the inflammatory cytokine IL-1β.
Demand and Supply of Water for Agriculture: Influence of Topography and Climate in Pre-Alpine, Mesoscale Catchments  [PDF]
Jürg Fuhrer, Karsten Jasper
Natural Resources (NR) , 2012, DOI: 10.4236/nr.2012.33019
Abstract: With climate change, water may become limited for intensive agriculture even in regions presently considered “water-rich”. Information about the potential water requirement and its temporal and spatial variability can help to develop future water management plans. A case study was carried out for Switzerland with its highly complex pre-alpine topography and steep gradients in climate. The hydrological model WaSiM-ETH was used to simulate net irrigation requirement (NIR) for cropland, grassland and orchards using criteria to define irrigation periods based either on the water stress level (expressed by the ratio of actual (aET) to potential evapotranspiration ((pET) (Method 1) or on thresholds for soil water potential (Method 2). Simulations for selected catchments were carried out with a daily time step for the period 1981-2010 using a 500 × 500 m spatial resolution. Catchment-scale NIR ranged between 0 and 4.3 million m3 and 0 and 7.3 million m3 for the two methods, respectively, with no trend over the observation period in any catchment. During the heat wave in 2003, NIR increased by a factor of 1.5 to 2.3 relative to the mean, and in catchments where discharge is directly dependent on precipitation, NIR in the summer of 2003 reached the limits of river water availability. In contrast, in a region with water supply from glacier melt water, highest NIR in 2003 still remained far below total river discharge. The results show that NIR varies strongly between years and across the landscape, and even in a presently cool-temperate climate, irrigation may put pressure on regional water resources under extreme climatic conditions that may become more frequent by the end of the 21st century.
Leptogenesis, Gravitino Dark Matter and Entropy Production
Jasper Hasenkamp,J?rn Kersten
Physics , 2010, DOI: 10.1103/PhysRevD.82.115029
Abstract: Many extensions of the Standard Model predict super-weakly interacting particles, which typically have to decay before Big Bang Nucleosynthesis (BBN). The entropy produced in the decays may help to reconcile thermal leptogenesis and BBN in scenarios with gravitino dark matter, which is usually difficult due to late decays of the next-to-lightest supersymmetric particle (NLSP) spoiling the predictions of BBN. We study this possibility for a general neutralino NLSP. We elaborate general properties of the scenario and strong constraints on the entropy-producing particle. As an example, we consider the saxion from the axion multiplet and show that, while enabling a solution of the strong CP problem, it can also produce a suitable amount of entropy.
Dark and visible matter with broken R-parity and the axion multiplet
Jasper Hasenkamp,J?rn Kersten
Physics , 2011, DOI: 10.1016/j.physletb.2011.06.037
Abstract: A small breaking of R-parity reconciles thermal leptogenesis, gravitino dark matter and primordial nucleosynthesis. We find that the same breaking relaxes cosmological bounds on the axion multiplet. Naturally expected spectra become allowed and bounds from late particle decays become so weak that they are superseded by bounds from non-thermal axion production. In this sense, the strong CP problem serves as an additional motivation for broken R-parity.
Dark radiation from particle decay: cosmological constraints and opportunities
Jasper Hasenkamp,J?rn Kersten
Physics , 2012, DOI: 10.1088/1475-7516/2013/08/024
Abstract: We study particle decay as the origin of dark radiation. After elaborating general properties and useful parametrisations we provide model-independent and easy-to-use constraints from nucleosynthesis, the cosmic microwave background and structure formation. Bounds on branching ratios and mass hierarchies depend in a unique way on the time of decay. We demonstrate their power to exclude well-motivated scenarios taking the example of the lightest ordinary sparticle decaying into the gravitino. We point out signatures and opportunities in cosmological observations and structure formation. For example, if there are two dark decay modes, dark radiation and the observed dark matter with adjustable free-streaming can originate from the same decaying particle, solving small-scale problems of structure formation. Hot dark matter mimicking a neutrino mass scale as deduced from cosmological observations can arise and possibly be distinguished after a discovery. Our results can be used as a guideline for model building.
Pipeline Potential Leak Detection Technologies: Assessment and Perspective in the Nigeria Niger Delta Region  [PDF]
Jasper Agbakwuru
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.28121
Abstract: This paper examines the advances in pipeline third party encroachment alert systems and leak control methods in the oil/gas industry. It also highlights the extent of spill/pollution issues in the Niger Delta region due to intended/unin- tended damages and suggests a possible method of control. It is believed that the best option to avoid pollution due to pipeline failure is to ensure that hydrocarbon does not exit from the pipeline. With the different methods considered in this review, acoustic monitoring of change in the operational sound generated from a given pipeline section is suggested to be practicable to identifying sound abnormalities of third party encroachments. One established challenge of the acoustic system for buried pipelines protection is attenuation of acoustic transmission. An attempt to check the performance of an acoustic transmission on steel pipelines submerged in water points to a similar research on plastic water pipelines that attenuation is small compared with pipe buried in soil. Fortunately, Niger Delta of Nigeria is made of wetland, swamps and shallow water and could therefore offer an opportunity to deploy acoustic system for the safety of pipelines against third party attacks in this region. However, the numerous configuration and quantity of oil installation in this region imply that cost of application will be enormous. It is therefore suggested that a combination of impressed alternating cycle current (IACC) which traces encroachment on the pipeline coating and an acoustic system be used to manage intended and unintended pipeline potential damages. The IACC should be used for flow lines and other short distance delivery lines within the oilfield, while the relatively large diameter and long length delivery, trunk and transmission lines should be considered for acoustic protection. It is, however, noted that further efforts are required to reduce cost and improve effectiveness of these systems.
Oil/Gas Pipeline Leak Inspection and Repair in Underwater Poor Visibility Conditions: Challenges and Perspectives  [PDF]
Agbakwuru Jasper
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.35049
Abstract: Mechanical pressure clamps are examples of innovative tools commonly used in the oil and gas industry for arresting leaks from damaged oil and gas pipelines. However, if leaks result from pipeline rupture, clamps are not usually recommended. It is therefore obvious that inspection of the leaking pipeline is very crucial in deciding the strategy for repair. For subsea pipelines where underwater poor visibility is pronounced, this important aspect of the pipeline repair process becomes difficult to implement. The result is a repair-leak-repair cycle. This challenge is commonly found in repairs of old pipelines in unclear water conditions. Old pipelines and their vulnerability to fractures that often lead to ruptures are discussed. In this paper, the challenges and technologies available for visualisation and examination in such unclear water conditions are discussed. There appears to be a gap in the existing pipeline integrity management system with respect to inspection and repair of pipelines in unclear water conditions. This gap needs to be filled in order to minimise spills and pollution. For pipelines installed in unclear water condition, a perspective is suggested to extend the capability of existing remotely operated vehicles to employ the use of clear laminar water system or a related technique to provide integrity engineers and operators with close visual assess to inspect leaking pipelines and effect adequate repairs. This paper suggests that the use of optical eye as the main tool for examination remains valuable in managing the challenges in underwater pipeline repairs in unclear water condition.
Chemokine blockade: a new era in the treatment of rheumatoid arthritis?
Jasper J Haringman, Paul P Tak
Arthritis Research & Therapy , 2004, DOI: 10.1186/ar1172
Abstract: Chemokines form a large superfamily of small (8–14 kDa) cytokines that play crucial roles in cell migration. They interact with G-protein-coupled receptors, which possess a seven transmembrane domain. To date about 50 chemokines have been identified that signal through some 20 distinct receptors [1].A subset of the chemokine family is active under normal physiological conditions. These so-called homeostatic chemokines are involved in maintaining normal leucocyte traffic and cell compartmentalization in lymphoid tissues under non-inflammatory conditions [2].Most chemokines play a role in inflammatory conditions by inducing integrin activation, chemotaxis, and angiogenesis. Apart from modulating migration directly, chemokines can stimulate cells to release (pro)inflammatory mediators such as cytokines and matrix metalloproteinases [3]. Increased expression of inflammatory chemokines has been found in many inflammatory disorders, including hepatic disease, multiple sclerosis, transplant rejection and inflammatory bowel disease [4]. Analysis of synovial tissue, synovial fluid and peripheral blood from patients with rheumatoid arthritis (RA) revealed abundant expression of a variety of inflammatory chemokines and their receptors [5,6]. In vitro studies have suggested that both so-called homeostatic chemokines and inflammatory chemokines, including CC chemokine receptor (CCR)1, CCR2, CCR5, CC chemokine ligand (CCL)2/monocyte chemoattractant protein (MCP)-1, CCL5/RANTES (regulated on activation, normal T-cell expressed and secreted) and CXCL8/IL-8, are intimately involved in cell migration toward the synovial compartment in RA [7-10].Although these studies might suggest therapeutic potential for chemokine and chemokine receptor blockade in inhibiting chronic synovial inflammation, there are some possible pitfalls that could hamper the clinical use of this approach. Of particular importance is the redundancy of the system, based on in vitro studies. Because one receptor can
Slipins: ancient origin, duplication and diversification of the stomatin protein family
Jasper B Green, J Peter W Young
BMC Evolutionary Biology , 2008, DOI: 10.1186/1471-2148-8-44
Abstract: We have constructed a comprehensive phylogeny of all 'stomatin-like' sequences that share a 150 amino acid domain. We show these proteins comprise an ancient family that arose early in prokaryotic evolution, and we propose a new nomenclature that reflects their phylogeny, based on the name "slipin" (stomatin-like protein). Within prokaryotes there are two distinct subfamilies that account for the two different origins of the eight eukaryotic stomatin subfamilies, one of which gave rise to eukaryotic SLP-2, renamed here "paraslipin". This was apparently acquired through the mitochondrial endosymbiosis and is widely distributed amongst the major kingdoms. The other prokaryotic subfamily gave rise to the ancestor of the remaining seven eukaryotic subfamilies. The highly diverged "alloslipin" subfamily is represented only by fungal, viral and ciliate sequences. The remaining six subfamilies, collectively termed "slipins", are confined to metazoa. Protostome stomatin, as well as a newly reported arthropod subfamily slipin-4, are restricted to invertebrate groups, whilst slipin-1 (previously SLP-1) is present in nematodes and higher metazoa. In vertebrates, the stomatin family expanded considerably, with at least two duplication events giving rise to podocin and slipin-3 subfamilies (previously SLP-3), with the retained ancestral sequence giving rise to vertebrate stomatin.Stomatin-like proteins have their origin in an ancient duplication event that occurred early on in the evolution of prokaryotes. By constructing a phylogeny of this family, we have identified and named a number of orthologous groups: these can now be used to infer function of stomatin subfamilies in a meaningful way.Human stomatin (hstomatin) was first identified as an integral membrane protein in human red blood cells [1-3]. It has since been shown to be expressed in many cell types and organisms, although hstomatin function remains unclear [4]. Loss of stomatin in humans is associated with a condition
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