1,113 research outputs found

    Caspase I-related protease inhibition retards the execution of okadaic acid- and camptothecin-induced apoptosis and PAI-2 cleavage, but not commitment to cell death in HL-60 cells

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    We have previously reported that the putative cytoprotective protease inhibitor, plasminogen activator inhibitor type 2 (PAI-2), is specifically cleaved during okadaic acid-induced apoptosis in a myeloid leukaemic cell line (Br J Cancer (1994) 70: 834–840). HL-60 cells exposed to okadaic acid and camptothecin underwent morphological and biochemical changes typical of apoptosis, including internucleosomal DNA fragmentation and PAI-2 cleavage. Significant endogenous PAI-2 cleavage was observed 9 h after exposure to okadaic acid; thus correlating with other signs of macromolecular degradation, like internucleosomal DNA fragmentation. In camptothecin-treated cells, PAI-2 cleavage was an early event, detectable after 2 h of treatment, and preceding internucleosomal DNA fragmentation. The caspase I selective protease inhibitor, YVAD-cmk, inhibited internucleosomal DNA fragmentation and PAI-2 cleavage of okadaic acid and camptothecin-induced apoptotic cells. YVAD-cmk rather sensitively and non-toxically inhibited camptothecin-induced morphology, but not okadaic acid-induced morphology. In in vitro experiments recombinant PAI-2 was not found to be a substrate for caspase I. The results suggest that caspase I selective protease inhibition could antagonize parameters coupled to the execution phase of okadaic acid- and camptothecin-induced apoptosis, but not the commitment to cell death. © 1999 Cancer Research Campaig

    Extracellular Matrix Aggregates from Differentiating Embryoid Bodies as a Scaffold to Support ESC Proliferation and Differentiation

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    Embryonic stem cells (ESCs) have emerged as potential cell sources for tissue engineering and regeneration owing to its virtually unlimited replicative capacity and the potential to differentiate into a variety of cell types. Current differentiation strategies primarily involve various growth factor/inducer/repressor concoctions with less emphasis on the substrate. Developing biomaterials to promote stem cell proliferation and differentiation could aid in the realization of this goal. Extracellular matrix (ECM) components are important physiological regulators, and can provide cues to direct ESC expansion and differentiation. ECM undergoes constant remodeling with surrounding cells to accommodate specific developmental event. In this study, using ESC derived aggregates called embryoid bodies (EB) as a model, we characterized the biological nature of ECM in EB after exposure to different treatments: spontaneously differentiated and retinoic acid treated (denoted as SPT and RA, respectively). Next, we extracted this treatment-specific ECM by detergent decellularization methods (Triton X-100, DOC and SDS are compared). The resulting EB ECM scaffolds were seeded with undifferentiated ESCs using a novel cell seeding strategy, and the behavior of ESCs was studied. Our results showed that the optimized protocol efficiently removes cells while retaining crucial ECM and biochemical components. Decellularized ECM from SPT EB gave rise to a more favorable microenvironment for promoting ESC attachment, proliferation, and early differentiation, compared to native EB and decellularized ECM from RA EB. These findings suggest that various treatment conditions allow the formulation of unique ESC-ECM derived scaffolds to enhance ESC bioactivities, including proliferation and differentiation for tissue regeneration applications. © 2013 Goh et al

    Sight-threatening Graves’ orbitopathy: Twenty years’ experience of a multidisciplinary thyroid-eye outpatient clinic

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    CONTEXT: Sight-threatening Graves' orbitopathy affects 3% to 5% of patients with Graves' orbitopathy. OBJECTIVES: To describe the management of patients with sight-threatening Graves' orbitopathy seen in a multidisciplinary thyroid-eye outpatient clinic dedicated to Graves' orbitopathy (GO). PATIENTS AND METHODS: We enrolled all patients with sight-threatening GO (dysthyroid optic neuropathy and corneal ulcer as defined in the EUGOGO statement) seen and treated in our GO multidisciplinary thyroid-eye outpatient clinic over the last two decades. RESULTS: A total of 31 patients (median age 51 years old) including 24 women (77%) and 58% active smokers. This population represented 47 cases (case = eye) of sight-threatening GO. Dysthyroid optic neuropathy (DON) occurred in 40 eyes, corneal ulcer in 15 eyes and both in 8. At presentation, the clinical features of DON were reduced visual acuity (85%), visual field defects (80%), optic disc swelling (42%) and reduced colour vision (100%). At one year, surgical orbital decompression (OD) was performed in 82.5% of DON cases. Only seven eyes with DON were treated with pulses of intra-venous glucocorticoids. For 10 patients, several therapeutic strategies (OD n = 4, punctal plug n = 1, amniotic membrane graft n = 2, tarsorrhaphy n = 2, botulinum toxin injection = 3 and eyelid surgery n = 2) were used to treat corneal ulcer. For each ophthalmological parameter, more than 85% of DON cases had recovery or improvement after treatment. For visual acuity in corneal ulcer, it was 71.4%. CONCLUSION: We report 47 cases of sight-threatening GO. Orbital decompression was performed in the majority of DON cases and several therapeutic strategies were necessary to treat corneal ulcer. The results are satisfactory in sight-threatening Graves' orbitopathy due to multidisciplinary management

    Timing of crystallization of the lunar magma ocean constrained by the oldest zircon

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    The Moon is thought to have formed through the consolidationof debris from the collision of a Mars-sized body with the Earthmore than 4,500 million years ago. The primitive Moon wascovered with a thick layer of melt known as the lunar magmaocean1, the crystallization of which resulted in the Moon?ssurface as it is observed today. There is considerable debate,however, over the precise timing and duration of the processof magma ocean crystallization. Here we date a zircon fromlunar breccias to an age of 4,4176 million years. This dateprovides a precise younger age limit for the solidification ofthe lunar magma ocean. We propose a model that suggestsan exponential rate of lunar crystallization, based on acombination of this oldest known lunar zircon and the age of theMoon-forming giant impact. We conclude that the formationof the Moon?s anorthositic crust followed the solidification of80?85% of the original melt, within about 100 million years ofthe collision. The existence of younger zircons2 is indicative ofthe continued solidification of a small percentage of melt for anextra 200?400 million years

    Assessing the effects of spatial discretization on large-scale flow model performance and prediction uncertainty

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    Large-scale physically-based and spatially-distributed models (>100 km2) constitute useful tools for water management since they take explicitly into account the heterogeneity and the physical processes occurring in the subsurface for predicting the evolution of discharge and hydraulic heads for several predictive scenarios. However, such models are characterized by lengthy execution times. Therefore, modelers often coarsen spatial discretization of large-scale physically-based and spatially-distributed models for reducing the number of unknowns and the execution times. This study investigates the influence of such a coarsening of model grid on model performance and prediction uncertainty. The improvement of model performance obtained with an automatic calibration process is also investigated. The results obtained show that coarsening spatial discretization mainly influences the simulation of discharge due to a poor representation of surface water network and a smoothing of surface slopes that prevents from simulating properly surface water-groundwater interactions and runoff processes. Parameter sensitivities are not significantly influenced by grid coarsening and calibration can compensate, to some extent, for model errors induced by grid coarsening. The results also show that coarsening spatial discretization mainly influences the uncertainty on discharge predictions. However, model prediction uncertainties on discharge only increase significantly for very coarse spatial discretizations.Peer reviewe

    Synchronous malignant vagal paraganglioma with contralateral carotid body paraganglioma treated by radiation therapy

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    Paragangliomas are rare tumors and very few cases of malignant vagal paraganglioma with synchronous carotid body paraganglioma have been reported. We report a case of a 20-year old male who presented with slow growing bilateral neck masses of eight years duration. He had symptoms of dysphagia to solids, occasional mouth breathing and hoarseness of voice. Fine needle aspiration cytology (FNAC) performed where he lived showed a sinus histiocytosis and he was administered anti-tubercular treatment for six months without any improvement in his symptoms. His physical examination revealed pulsatile, soft to firm, non-tender swellings over the anterolateral neck confined to the upper-mid jugulo-diagastric region on both sides. Direct laryngoscopy examination revealed a bulge on the posterior pharyngeal wall and another over the right lateral pharyngeal wall. Magnetic resonance imaging (MRI), 99mTc-labeled octreotide scan and angiography diagnosed the swellings as carotid body paraganglioma, stage III on the right side with left-sided vagal malignant paraganglioma. Surgery was ruled out as a high morbidity with additional risk to life was expected due to the highly vascular nature of the tumor. The patient was treated with radiation therapy by image guided radiation to a dose of 5040cGy in 28 fractions. At a follow-up at 16 months, the tumors have regressed bilaterally and the patient can take solids with ease

    Muon Track Reconstruction and Data Selection Techniques in AMANDA

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    The Antarctic Muon And Neutrino Detector Array (AMANDA) is a high-energy neutrino telescope operating at the geographic South Pole. It is a lattice of photo-multiplier tubes buried deep in the polar ice between 1500m and 2000m. The primary goal of this detector is to discover astrophysical sources of high energy neutrinos. A high-energy muon neutrino coming through the earth from the Northern Hemisphere can be identified by the secondary muon moving upward through the detector. The muon tracks are reconstructed with a maximum likelihood method. It models the arrival times and amplitudes of Cherenkov photons registered by the photo-multipliers. This paper describes the different methods of reconstruction, which have been successfully implemented within AMANDA. Strategies for optimizing the reconstruction performance and rejecting background are presented. For a typical analysis procedure the direction of tracks are reconstructed with about 2 degree accuracy.Comment: 40 pages, 16 Postscript figures, uses elsart.st

    Quantification of Optic Disc Edema during Exposure to High Altitude Shows No Correlation to Acute Mountain Sickness

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    BACKGROUND: The study aimed to quantify changes of the optic nerve head (ONH) during exposure to high altitude and to assess a correlation with acute mountain sickness (AMS). This work is related to the Tuebingen High Altitude Ophthalmology (THAO) study. METHODOLOGY/PRINCIPAL FINDINGS: A confocal scanning laser ophthalmoscope (cSLO, Heidelberg Retina Tomograph, HRT3®) was used to quantify changes at the ONH in 18 healthy participants before, during and after rapid ascent to high altitude (4559 m). Slitlamp biomicroscopy was used for clinical optic disc evaluation; AMS was assessed with Lake Louise (LL) and AMS-cerebral (AMS-c) scores; oxygen saturation (SpO₂) and heart rate (HR) were monitored. These parameters were used to correlate with changes at the ONH. After the first night spent at high altitude, incidence of AMS was 55% and presence of clinical optic disc edema (ODE) 79%. Key stereometric parameters of the HRT3® used to describe ODE (mean retinal nerve fiber layer [RNFL] thickness, RNFL cross sectional area, optic disc rim volume and maximum contour elevation) changed significantly at high altitude compared to baseline (p<0.05) and were consistent with clinically described ODE. All changes were reversible in all participants after descent. There was no significant correlation between parameters of ODE and AMS, SpO₂ or HR. CONCLUSIONS/SIGNIFICANCE: Exposure to high altitude leads to reversible ODE in the majority of healthy subjects. However, these changes did not correlate with AMS or basic physiologic parameters such as SpO₂ and HR. For the first time, a quantitative approach has been used to assess these changes during acute, non-acclimatized high altitude exposure. In conclusion, ODE presents a reaction of the body to high altitude exposure unrelated to AMS
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