102 research outputs found

    Spinning Conformal Correlators

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    We develop the embedding formalism for conformal field theories, aimed at doing computations with symmetric traceless operators of arbitrary spin. We use an index-free notation where tensors are encoded by polynomials in auxiliary polarization vectors. The efficiency of the formalism is demonstrated by computing the tensor structures allowed in n-point conformal correlation functions of tensors operators. Constraints due to tensor conservation also take a simple form in this formalism. Finally, we obtain a perfect match between the number of independent tensor structures of conformal correlators in d dimensions and the number of independent structures in scattering amplitudes of spinning particles in (d+1)-dimensional Minkowski space.Comment: 46 pages, 3 figures; V2: references added; V3: tiny misprint corrected in (A.9

    Spinning Conformal Blocks

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    For conformal field theories in arbitrary dimensions, we introduce a method to derive the conformal blocks corresponding to the exchange of a traceless symmetric tensor appearing in four point functions of operators with spin. Using the embedding space formalism, we show that one can express all such conformal blocks in terms of simple differential operators acting on the basic scalar conformal blocks. This method gives all conformal blocks for conformal field theories in three dimensions. We demonstrate how this formalism can be applied in a few simple examples.Comment: 29 page

    Adjuvant radiotherapy for primary breast cancer in BRCA1 and BRCA2 mutation carriers and risk of contralateral breast cancer with special attention to patients irradiated at younger age

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    The purpose of this study was to estimate the influence of adjuvant radiotherapy for primary breast cancer (BC) on the risk of contralateral BC (CBC) in BRCA1 or BRCA2(BRCA1/2) mutation carriers, with special attention to patients irradiated at age younger than 40Β years. Additionally, tendencies in locoregional treatments and rates of contralateral risk-reducing mastectomy over time were explored. In this retrospective cohort study, 691 BRCA1/2-associated BC patients treated between 1980 and 2013 were followed from diagnosis until CBC or censoring event including ipsilateral BC recurrence, distant metastasis, contralateral risk-reducing mastectomy, other invasive cancer diagnosis, death, or loss to follow up. Hazard ratios (HR) for CBC associated with radiotherapy were estimated using Cox regression. Median follow-up time was 8.6Β years [range 0.3–34.3Β years]. No association between radiotherapy for primary BC and risk of CBC was found, neither in the total population (HR 0.82, 95Β % CI 0.45–1.49) nor in the subgroup of patients younger than 40Β years at primary diagnosis (HR 1.36, 95Β % CI 0.60–3.09). During follow-up, the number of patients at risk decreased substantially since a large proportion of patients were censored after contralateral risk-reducing mastectomy or BC recurrence. Over the years, increasing preference for mastectomy without radiotherapy compared to breast-conserving surgery with radiotherapy was found ranging from less than 30Β % in 1995 to almost 50Β % after 2010. The rate of contralateral risk-reducing mastectomy increased over the years from less than 40Β % in 1995 to more than 60Β % after 2010. In this cohort of BRCA1/2-associated BC patients, no association between radiotherapy for primary BC and risk of CBC was observed in the total group, nor in the patients irradiated before the age of 40Β years. The number of patients at risk after 10 and 15Β years of follow-up, however, was too small to definitively exclude harmful effects of adjuvant radiotherapy

    Nitric oxide differentially regulates renal ATP-binding cassette transporters during endotoxemia

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    Nitric oxide (NO) is an important regulator of renal transport processes. In the present study, we investigated the role of NO, produced by inducible NO synthase (iNOS), in the regulation of renal ATP-binding cassette (ABC) transporters in vivo during endotoxemia. Wistar–Hannover rats were injected with lipopolysaccharide (LPS+) alone or in combination with the iNOS inhibitor, aminoguanidine. Controls received detoxified LPS (LPSβˆ’). After LPS+, proximal tubular damage and a reduction in renal function were observed. Furthermore, iNOS mRNA and protein, and the amount of NO metabolites in plasma and urine, increased compared to the LPSβˆ’ group. Coadministration with aminoguanidine resulted in an attenuation of iNOS induction and reduction of renal damage. Gene expression of 20 ABC transporters was determined. After LPS+, a clear up-regulation in Abca1, Abcb1/P-glycoprotein (P-gp), Abcb11/bile salt export pump (Bsep), and Abcc2/multidrug resistance protein (Mrp2) was found, whereas Abcc8 was down-regulated. Up-regulation of Abcc2/Mrp2 was accompanied by enhanced calcein excretion. Aminoguanidine attenuated the effects on transporter expression. Our data indicate that NO, produced locally by renal iNOS, regulates the expression of ABC transporters in vivo. Furthermore, we showed, for the first time, expression and subcellular localization of Abcb11/Bsep in rat kidney

    Comparison of Human Memory CD8 T Cell Responses to Adenoviral Early and Late Proteins in Peripheral Blood and Lymphoid Tissue

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    Treatment of invasive adenovirus (Ad) disease in hematopoietic stem cell transplant (SCT) recipients with capsid protein hexon-specific donor T cells is under investigation. We propose that cytotoxic T cells (CTLs) targeted to the late protein hexon may be inefficient in vivo because the early Ad protein E3-19K downregulates HLA class I antigens in infected cells. In this study, CD8+ T cells targeted to highly conserved HLA A2-restricted epitopes from the early regulatory protein DNA polymerase (P-977) and late protein hexon (H-892) were compared in peripheral blood (PB) and tonsils of naturally infected adults. In tonsils, epitope-specific pentamers detected a significantly higher frequency of P-977+CD8+ T cells compared to H-892+CD8+ T cells; this trend was reversed in PB. Tonsil epitope-specific CD8+ T cells expressed IFN-Ξ³ and IL-2 but not perforin or TNF-Ξ±, whereas PB T cells were positive for IFN-Ξ³, TNF-Ξ±, and perforin. Tonsil epitope-specific T cells expressed lymphoid homing marker CCR7 and exhibited lower levels of the activation marker CD25 but higher proliferative potential than PB T cells. Finally, in parallel with the kinetics of mRNA expression, P-977-specific CTLs lysed targets as early as 8 hrs post infection. In contrast, H-892-specific CTLs did not kill unless infected fibroblasts were pretreated with IFN-Ξ³ to up regulate HLA class I antigens, and cytotoxicity was delayed until 16–24 hours. These data show that, in contrast to hexon CTLs, central memory type DNA polymerase CTLs dominate the lymphoid compartment and kill fibroblasts earlier after infection without requiring exogenous IFN-Ξ³. Thus, use of CTLs targeted to both early and late Ad proteins may improve the efficacy of immunotherapy for life-threatening Ad disease in SCT recipients

    High-Throughput Identification of Potential Minor Histocompatibility Antigens by MHC Tetramer-Based Screening: Feasibility and Limitations

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    T-cell recognition of minor histocompatibility antigens (MiHA) plays an important role in the graft-versus-tumor (GVT) effect of allogeneic stem cell transplantation (allo-SCT). However, the number of MiHA identified to date remains limited, making clinical application of MiHA reactive T-cell infusion difficult. This study represents the first attempt of genome-wide prediction of MiHA, coupled to the isolation of T-cell populations that react with these antigens. In this unbiased high-throughput MiHA screen, both the possibilities and pitfalls of this approach were investigated. First, 973 polymorphic peptides expressed by hematopoietic stem cells were predicted and screened for HLA-A2 binding. Subsequently a set of 333 high affinity HLA-A2 ligands was identified and post transplantation samples from allo-SCT patients were screened for T-cell reactivity by a combination of pMHC-tetramer-based enrichment and multi-color flow cytometry. Using this approach, 71 peptide-reactive T-cell populations were generated. The isolation of a T-cell line specifically recognizing target cells expressing the MAP4K1IMA antigen demonstrates that identification of MiHA through this approach is in principle feasible. However, with the exception of the known MiHA HMHA1, none of the other T-cell populations that were generated demonstrated recognition of endogenously MiHA expressing target cells, even though recognition of peptide-loaded targets was often apparent

    Cross-Reactivity of Herpesvirus-Specific CD8 T Cell Lines Toward Allogeneic Class I MHC Molecules

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    Although association between persistent viral infection and allograft rejection is well characterized, few examples of T-cell cross-reactivity between self-MHC/viral and allogeneic HLA molecules have been documented so far. We appraised in this study the alloreactivity of CD8 T cell lines specific for immunodominant epitopes from human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV). CD8 T cell lines were generated after sorting with immunomagnetic beads coated with either pp65495–503/A*0201, BMLF1259–267/A*0201, or BZLF154–64/B*3501 multimeric complexes. Alloreactivity of the CD8 T cell lines against allogeneic class I MHC alleles was assessed by screening of (i) TNF-Ξ± production against COS-7 cells transfected with as many as 39 individual HLA class I-encoding cDNA, and (ii) cytotoxicity activity toward a large panel of HLA-typed EBV-transformed B lymphoblastoid cell lines. We identified several cross-reactive pp65/A*0201-specific T cell lines toward allogeneic HLA-A*3001, A*3101, or A*3201. Moreover, we described here cross-recognition of HLA-Cw*0602 by BZLF1/B*3501-specific T cells. It is noteworthy that these alloreactive CD8 T cell lines showed efficient recognition of endothelial cells expressing the relevant HLA class I allele, with high level TNF-Ξ± production and cytotoxicity activity. Taken together, our data support the notion that herpes virus-specific T cells recognizing allo-HLA alleles may promote solid organ rejection

    Identification of Small Molecule Lead Compounds for Visceral Leishmaniasis Using a Novel Ex Vivo Splenic Explant Model System

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    Visceral leishmaniasis is a life threatening parasitic disease present in several countries of the world. New drugs are needed to treat this disease because treatments are becoming increasingly ineffective. We established a novel system to screen for new anti-leishmanial compounds that utilizes spleen cells from hamsters infected with the parasite Leishmania donovani. The parasite strain we used was genetically engineered to emit light by the incorporation of the firefly luciferase gen. This laboratory test system has the advantage of reproducing the cellular environment where the drug has to combat the infection. The efficacy of the compounds is easily determined by measuring the light emitted by the surviving parasites in a luminometer after exposing the infected cells to the test compounds. The screening of more than 4,000 molecules showed that 84 (2.1%) of them showed anti-leishmanial activity and had an acceptable toxicity evaluation. Eighty two percent of these molecules, which had varied chemical structures, were previously unknown to have anti-leishmanial activity. Further studies in animals of these new chemical entities may identify drug candidates for the treatment of visceral leishmaniasis

    Germline variants and breast cancer survival in patients with distant metastases at primary breast cancer diagnosis

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    Breast cancer metastasis accounts for most of the deaths from breast cancer. Identification of germline variants associated with survival in aggressive types of breast cancer may inform understanding of breast cancer progression and assist treatment. In this analysis, we studied the associations between germline variants and breast cancer survival for patients with distant metastases at primary breast cancer diagnosis. We used data from the Breast Cancer Association Consortium (BCAC) including 1062 women of European ancestry with metastatic breast cancer, 606 of whom died of breast cancer. We identified two germline variants on chromosome 1, rs138569520 and rs146023652, significantly associated with breast cancer-specific survival (P = 3.19 × 10βˆ’8 and 4.42 × 10βˆ’8). In silico analysis suggested a potential regulatory effect of the variants on the nearby target genes SDE2 and H3F3A. However, the variants showed no evidence of association in a smaller replication dataset. The validation dataset was obtained from the SNPs to Risk of Metastasis (StoRM) study and included 293 patients with metastatic primary breast cancer at diagnosis. Ultimately, larger replication studies are needed to confirm the identified associations
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