996 resultados para Intracellular localization


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Recently we demonstrated that human mast cells (MC) express functional TRAIL death receptors. Here we assessed the expression of TRAIL on both mRNA and protein level in cord blood derived MC (CBMC) and HMC-1. The TRAIL release either spontaneous or induced by LPS, IFN-gamma and IgE-dependent activation, was evaluated as well. The protein location was restricted to the intracellular compartment in CBMC, but not in HMC-1. The intracellular TRAIL was not localized inside the granules. The treatment with IFN-gamma and LPS up-regulated intracellular TRAIL expression in CBMC, but did not induce its release. These in vitro data show that human MC can produce and express intracellular TRAIL whose location could not be altered by different stimuli.

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This study addresses the cellular uptake and intracellular trafficking of 15-nm gold nanoparticles (NPs), either plain (i.e., stabilized with citrate) or coated with polyethylene glycol (PEG), exposed to human alveolar epithelial cells (A549) at the air-liquid interface for 1, 4, and 24 h. Quantitative analysis by stereology on transmission electron microscopy images reveals a significant, nonrandom intracellular distribution for both NP types. No particles are observed in the nucleus, mitochondria, endoplasmic reticulum, or golgi. The cytosol is not a preferred cellular compartment for both NP types, although significantly more PEG-coated than citrate-stabilized NPs are present there. The preferred particle localizations are vesicles of different sizes (<150, 150-1000, >1000 nm). This is observed for both NP types and indicates a predominant uptake by endocytosis. Subsequent inhibition of caveolin- and clathrin-mediated endocytosis by methyl-beta-cyclodextrin (MbetaCD) results in a significant reduction of intracellular NPs. The inhibition, however, is more pronounced for PEG-coated than citrate-stabilized NPs. The latter are mostly found in larger vesicles; therefore, they are potentially taken up by macropinocytosis, which is not inhibited by MbetaCD. With prolonged exposure times, both NPs are preferentially localized in larger-sized intracellular vesicles such as lysosomes, thus indicating intracellular particle trafficking. This quantitative evaluation reveals that NP surface coatings modulate endocytotic uptake pathways and cellular NP trafficking. Other nonendocytotic entry mechanisms are found to be involved as well, as indicated by localization of a minority of PEG-coated NPs in the cytosol.

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Tooth resorption is among the most common and most challenging problems in feline dentistry It is a progressive disease eventually leading to tooth loss and often root replacement. The etiology of moth resorption remains obscure and to date no effective therapeutic approach is known. The present study is aimed at assessing the reliability of radiographic imaging and addressing the possible involvement of receptor activator of NF kappa B (RANK), its ligand (RANKL), and osteoprotegerin (OPG) in the process of tooth resorption. Teeth from 8 cats were investigated by means of radiographs and paraffin sections followed by immunolabeling. Six cats were diagnosed with tooth resorption based on histopathologic and radiographic findings. Samples were classified according to a four-stage diagnostic system. Radiologic assessment of tooth resorption correlated very strongly with histopathologic findings. Tooth resorption was accompanied by a strong staining with all three antibodies used, especially with anti-RANK and anti-RANKL antibodies. The presence of OPG and RANKL at the resorption site is indicative of repair attempts by fibroblasts and stromal cells. These findings should be extended by further investigations in order to elucidate the pathophysiologic processes underlying tooth resorption that might lead to prophylactic and/or therapeutic measures. J Vet Dent 27(2); 75 - 83, 2010

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Cytoplasmic dynein in filamentous fungi accumulates at microtubule plus-ends near the hyphal tip, which is important for minus-end-directed transport of early endosomes. It was hypothesized that dynein is switched on at the plus-end by cargo association. Here, we show in Aspergillus nidulans that kinesin-1-dependent plus-end localization is not a prerequisite for dynein ATPase activation. First, the Walker A and Walker B mutations in the dynein heavy chain AAA1 domain implicated in blocking different steps of the ATPase cycle cause different effects on dynein localization to microtubules, arguing against the suggestion that ATPase is inactive before arriving at the plus-end. Second, dynein from kinA (kinesin 1) mutant cells has normal ATPase activity despite the absence of dynein plus-end accumulation. In kinA hyphae, dynein localizes along microtubules and does not colocalize with abnormally accumulated early endosomes at the hyphal tip. This is in contrast to the colocalization of dynein and early endosomes in the absence of NUDF/LIS1. However, the Walker B mutation allows dynein to colocalize with the hyphal-tip-accumulated early endosomes in the kinA background. We suggest that the normal ability of dyenin to interact with microtubules as an active minus-end-directed motor demands kinesin-1-mediated plus-end accumulation for effective interactions with early endosomes.

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Cardiogoniometry (CGM), a spatiotemporal electrocardiologic 5-lead method with automated analysis, may be useful in primary healthcare for detecting coronary artery disease (CAD) at rest. Our aim was to systematically develop a stenosis-specific parameter set for global CAD detection. In 793 consecutively admitted patients with presumed non-acute CAD, CGM data were collected prior to elective coronary angiography and analyzed retrospectively. 658 patients fulfilled the inclusion criteria, 405 had CAD verified by coronary angiography; the 253 patients with normal coronary angiograms served as the non-CAD controls. Study patients--matched for age, BMI, and gender--were angiographically assigned to 8 stenosis-specific CAD categories or to the controls. One CGM parameter possessing significance (P < .05) and the best diagnostic accuracy was matched to one CAD category. The area under the ROC curve was .80 (global CAD versus controls). A set containing 8 stenosis-specific CGM parameters described variability of R vectors and R-T angles, spatial position and potential distribution of R/T vectors, and ST/T segment alterations. Our parameter set systematically combines CAD categories into an algorithm that detects CAD globally. Prospective validation in clinical studies is ongoing.

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To reduce the risk of disabling postoperative functional deficit in patients with lesions in the dominant hemisphere, information about the localization of eloquent language areas is mandatory.

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The ATP-binding cassette transporter A1 (ABCA1) mediates the transport of cholesterol, phospholipids, and other lipophilic molecules across cellular membranes. Recent data provide evidence that ABCA1 plays an important role in placental function but the exact cellular sites of ABCA1 action in the placenta remain controversial. To clarify this issue, we analyzed the cellular and subcellular localization of ABCA1 with immunocytochemistry, immunofluorescence and subsequent confocal or immunofluorescence microscopy in different types of isolated primary placenta cells: cytotrophoblast cells, amnion epithelial cells, villous macrophages (Hofbauer cells), and mesenchymal cells isolated from chorionic membrane and placental villi. After 12 h of cultivation, primary cytotrophoblast cells showed intensive membrane and cytoplasmic staining for ABCA1. After 24 h, with progressive syncytium formation, ABCA1 staining intensity was markedly reduced and ABCA1 was dispersed in the cytoplasm of the forming syncytial layer. In amnion epithelial cells, placental macrophages and mesenchymal cells, ABCA1 was predominantly localized at the cell membrane and cytoplasmic compartments partially corresponding to the endoplasmic reticulum. In these cell types, the ABCA1 staining intensity was not dependent on the cultivation time. In conclusion, ABCA1 shows marked expression levels in diverse placental cell types. The multitopic localization of ABCA1 in diverse human placental cells not all directly involved in materno-fetal exchange suggests that this protein may not only participate in transplacental lipid transport but could have additional regulatory functions.

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Radiofrequency neurotomy is a recognized treatment for cervical zygapophysial joint pain. In several studies, the method has provided complete pain relief in 60-70% of the patients for approximately 9 months. The validated technique has the disadvantage of procedural times of 2-4 hours because several lesions are performed to take into account the variable nerve course. We tested the hypothesis that ultrasound localization of the nerves would enable us to reduce the number of lesions performed, while reaching the benchmark of at least 80% pain relief in 80% of patients with a median duration of 35 weeks, as achieved by a previous investigation using the standard method.

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The purpose of the current research project is to design a successful in-situ hybridization to identify regions within the brains of honeybees where DWV replicates. The localization of the virus in the brains of the bees can draw a connection between CCDand DWV.In conclusion, these results demonstrate that in bees infected with DWV the virus replicates actively in very important regions of the brain, including neuropils that are responsible for vision and olfaction. This means that the virus could adversely affect the vision and olfaction of the honeybees making it difficult for bees to behave normally.

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To determine the subcellular localization of the tegument proteins pp65, pp71, pp150, and pp28 as fusions to one of several fluorescent proteins. Since these tegument proteins play pivotal roles in several stages of the viral life cycle, knowledge of where and the mechanism of how these proteins localize upon release could result in a better understanding of their function during a lytic infection as well as assist in the development of an effective, novel antiviral treatment.

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Apis mellifera L., the European honeybee, is a crucial pollinator of many important agricultural crops in the United States. Recently, honeybee colonies have been affected by Colony Collapse Disorder (CCD), a disorder in which the colony fails due to the disappearance of a key functional group of worker bees. Though no direct causalrelationship has been confirmed, hives that experience CCD have been shown to have a high incidence of Deformed Wing Virus (DWV), a common honeybee virus. While the genome sequence and gene-order of DWV has been analyzed fairly recently, few other studies have been performed to understand the molecular characterization of the virus.Since little is known about where DWV proteins localize in infected host cells, the objective of this project was to determine the subcellular localization of two of the important non-structural proteins that are encoded in the DWV genome. This project focused on the protein 3C, an autocatalytic protease which cleaves itself from a longer polyprotein and helps to cut all of the other proteins apart from one another so that they can become functional, and 3D, the RNA-dependent RNA polymerase (RdRp) which is critical for replication of the virus because it copies the viral genome. By tagging nested constructs containing these two proteins and tracking where they localized in living cells, this study aimed to better understand the replication of DWV and to elicit possible targetsfor further research on how to control the virus. Since DWV is a picorna-like virus, distantly related to human viruses such as polio, and picornavirus non-structural proteins aggregate at cellular membranes during viral replication, the major hypothesis was that the 3C and 3CD proteins would localize at cellular organelle membranes as well. Using confocal microscopy, both proteins were found to localize in the cytoplasm, but the 3CDprotein was found to be mostly diffuse cytoplasmic, and the 3C protein was found to localize more specifically on membranous structures just outside of the nucleus.