196 research outputs found

    Vortex dominance of the 0+ and 2+ glueball mass in SU(2) lattice gauge theory

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    The c-vortex ensembles are constructed by means of the recently proposed cooling method which gradually removes the SU(2)/Z_2 coset fields from the SU(2) lattice configurations and which thus reveals the Z_2 vortex vacuum texture. Using Teper's blocking method, the screening masses of the 0+ and the 2+ glueball is calculated from these vortex ensembles and compared with the masses obtained from full configurations. The masses of either case agree within the achieved numerical accuracy of 10%. As a byproduct, we find that the overlaps of the Teper operators with the glueball wavefunctions are significantly larger in the case of the c-vortex ensembles.Comment: 9 pages, 4 PS figures, LaTeX using eps

    Encountering competitors reduces clutch size and increases offspring size in a parasitoid with female–female fighting

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    Understanding the size of clutches produced by only one parent may require a game-theoretic approach: clutch size may affect offspring fitness in terms of future competitive ability. If larger clutches generate smaller offspring and larger adults are more successful in acquiring and retaining resources, clutch size optima should be reduced when the probability of future competitive encounters is higher. We test this using Goniozus nephantidis, a gregarious parasitoid wasp in which the assumption of size-dependent resource acquisition is met via female–female contests for hosts. As predicted, smaller clutches are produced by mothers experiencing competition, due to fewer eggs being matured and to a reduced proportion of matured eggs being laid. As assumed, smaller clutches generate fewer but larger offspring. We believe this is the first direct evidence for pre-ovipositional and game-theoretic clutch size adjustment in response to an intergenerational fitness effect when clutches are produced by a single individual

    Stress-induced TRAILR2 expression overcomes TRAIL resistance in cancer cell spheroids

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    The influence of 3D microenvironments on apoptosis susceptibility remains poorly understood. Here, we studied the susceptibility of cancer cell spheroids, grown to the size of micrometastases, to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Interestingly, pronounced, spatially coordinated response heterogeneities manifest within spheroidal microenvironments: In spheroids grown from genetically identical cells, TRAIL-resistant subpopulations enclose, and protect TRAIL-hypersensitive cells, thereby increasing overall treatment resistance. TRAIL-resistant layers form at the interface of proliferating and quiescent cells and lack both TRAILR1 and TRAILR2 protein expression. In contrast, oxygen, and nutrient deprivation promote high amounts of TRAILR2 expression in TRAIL-hypersensitive cells in inner spheroid layers. COX-II inhibitor celecoxib further enhanced TRAILR2 expression in spheroids, likely resulting from increased ER stress, and thereby re-sensitized TRAIL-resistant cell layers to treatment. Our analyses explain how TRAIL response heterogeneities manifest within well-defined multicellular environments, and how spatial barriers of TRAIL resistance can be minimized and eliminated

    The natural history of primary sclerosing cholangitis in 781 children. A multicenter, international collaboration

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    There are limited data on the natural history of primary sclerosing cholangitis (PSC) in children. We aimed to describe the disease characteristics and long-term outcomes of pediatric PSC. We retrospectively collected all pediatric PSC cases from 36 participating institutions and conducted a survival analysis from the date of PSC diagnosis to dates of diagnosis of portal hypertensive or biliary complications, cholangiocarcinoma, liver transplantation, or death. We analyzed patients grouped by disease phenotype and laboratory studies at diagnosis to identify objective predictors of long-term outcome. We identified 781 patients, median age 12 years, with 4,277 person-years of follow-up; 33% with autoimmune hepatitis, 76% with inflammatory bowel disease, and 13% with small duct PSC. Portal hypertensive and biliary complications developed in 38% and 25%, respectively, after 10 years of disease. Once these complications developed, median survival with native liver was 2.8 and 3.5 years, respectively. Cholangiocarcinoma occurred in 1%. Overall event-free survival was 70% at 5 years and 53% at 10 years. Patient groups with the most elevated total bilirubin, gamma-glutamyltransferase, and aspartate aminotransferase-to-platelet ratio index at diagnosis had the worst outcomes. In multivariate analysis PSC-inflammatory bowel disease and small duct phenotypes were associated with favorable prognosis (hazard ratios 0.6, 95% confidence interval 0.5-0.9, and 0.7, 95% confidence interval 0.5-0.96, respectively). Age, gender, and autoimmune hepatitis overlap did not impact long-term outcome. CONCLUSION: PSC has a chronic, progressive course in children, and nearly half of patients develop an adverse liver outcome after 10 years of disease; elevations in bilirubin, gamma-glutamyltransferase, and aspartate aminotransferase-to-platelet ratio index at diagnosis can identify patients at highest risk; small duct PSC and PSC-inflammatory bowel disease are more favorable disease phenotypes

    Post-resolution macrophages shape long-term tissue immunity and integrity in a mouse model of pneumococcal pneumonia

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    Resolving inflammation is thought to return the affected tissue back to homoeostasis but recent evidence supports a non-linear model of resolution involving a phase of prolonged immune activity. Here we show that within days following resolution of Streptococcus pneumoniae-triggered lung inflammation, there is an influx of antigen specific lymphocytes with a memory and tissue-resident phenotype as well as macrophages bearing alveolar or interstitial phenotype. The transcriptome of these macrophages shows enrichment of genes associated with prostaglandin biosynthesis and genes that drive T cell chemotaxis and differentiation. Therapeutic depletion of post-resolution macrophages, inhibition of prostaglandin E2 (PGE2) synthesis or treatment with an EP4 antagonist, MF498, reduce numbers of lung CD4+/CD44+/CD62L+ and CD4+/CD44+/CD62L-/CD27+ T cells as well as their expression of the α-integrin, CD103. The T cells fail to reappear and reactivate upon secondary challenge for up to six weeks following primary infection. Concomitantly, EP4 antagonism through MF498 causes accumulation of lung macrophages and marked tissue fibrosis. Our study thus shows that PGE2 signalling, predominantly via EP4, plays an important role during the second wave of immune activity following resolution of inflammation. This secondary immune activation drives local tissue-resident T cell development while limiting tissue injur

    Ursodeoxycholic Acid Therapy in Pediatric Primary Sclerosing Cholangitis : Predictors of Gamma Glutamyltransferase Normalization and Favorable Clinical Course

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    Objective To investigate patient factors predictive of gamma glutamyltransferase (GGT) normalization following ursodeoxycholic acid (UDCA) therapy in children with primary sclerosing cholangitis. Study design We retrospectively reviewed patient records at 46 centers. We included patients with a baseline serum GGT level >= 50 IU/L at diagnosis of primary sclerosing cholangitis who initiated UDCA therapy within 1 month and continued therapy for at least 1 year. We defined "normalization" as a GGT level Results We identified 263 patients, median age 12.1 years at diagnosis, treated with UDCA at a median dose of 15 mg/kg/d. Normalization occurred in 46%. Patients with normalization had a lower prevalence of Crohn's disease, lower total bilirubin level, lower aspartate aminotransferase to platelet ratio index, greater platelet count, and greater serum albumin level at diagnosis. The 5-year survival with native liver was 99% in those patients who achieved normalization vs 77% in those who did not. Conclusions Less than one-half of the patients treated with UDCA have a complete GGT normalization in the first year after diagnosis, but this subset of patients has a favorable 5-year outcome. Normalization is less likely in patients with a Crohn's disease phenotype or a laboratory profile suggestive of more advanced hepatobiliary fibrosis. Patients who do not achieve normalization could reasonably stop UDCA, as they are likely not receiving clinical benefit. Alternative treatments with improved efficacy are needed, particularly for patients with already-advanced disease.Peer reviewe
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