21 research outputs found

    Estimates of Black Hole Spin Properties of 55 Sources

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    Studies of black hole spin and other parameters as a function of redshift provide information about the physical state and merger and accretion histories of the systems. One way that black hole spin may be estimated is through observations of extended radio sources. These sources, powered by outflows from an AGN, allow the beam power and total outflow energy to be studied. In a broad class of models, the beam power of the outflow is related to the spin of the black hole. This relationship is used to estimate black hole spins for 55 radio sources. The samples studied include 7 FRII quasars and 19 FRII radio galaxies with redshifts between 0.056 and 1.79, and 29 radio sources associated with CD galaxies with redshifts between 0.0035 and 0.291. The FRII sources studied have estimated spin values of between about 0.2 and 1; there is a range of values at a given redshift, and the values tend to increase with increasing redshift. Results obtained for FRII quasars are very similar to those obtained for FRII galaxies. A broader range of spin values are obtained for the sample of radio sources associated with CD galaxies studied. The fraction of the spin energy extracted per outflow event is estimated and ranges from about 0.03 to 0.5 for FRII sources and 0.002 to about 1 for radio sources associated with CD galaxies; the data are consistent with this fraction being independent of redshift though the uncertainties are large. The results obtained are consistent with those predicted by numerical simulations that track the merger and accretion history of AGN, supporting the idea that, for AGN with powerful large-scale outflows, beam power is directly related to black hole spin.Comment: 13 pages; to appear in MNRA

    Brief research report: in-depth immunophenotyping reveals stability of CD19 CAR T-cells over time

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    Variability or stability might have an impact on treatment success and toxicity of CD19 CAR T-cells. We conducted a prospective observational study of 12 patients treated with Tisagenlecleucel for CD19+ B-cell malignancies. Using a 31-color spectral flow cytometry panel, we analyzed differentiation stages and exhaustion markers of CAR T-cell subsets prior to CAR T-cell infusion and longitudinally during 6 months of follow-up. The majority of activation markers on CAR T-cells showed stable expression patterns over time and were not associated with response to therapy or toxicity. Unsupervised cluster analysis revealed an immune signature of CAR T-cell products associated with the development of immune cell-associated neurotoxicity syndrome. Warranting validation in an independent patient cohort, in-depth phenotyping of CAR T-cell products as well as longitudinal monitoring post cell transfer might become a valuable tool to increase efficacy and safety of CAR T-cell therapy

    Placenta-specific methylation of the vitamin D 24-hydroxylase gene: implications for feedback autoregulation of active vitamin D levels at the fetomaternal interface

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    Plasma concentrations of biologically active vitamin D (1,25- (OH)2D) are tightly controlled via feedback regulation of renal 1-hydroxylase (CYP27B1; positive) and 24-hydroxylase (CYP24A1; catabolic) enzymes. In pregnancy, this regulation is uncoupled, and 1,25-(OH)2D levels are significantly elevated, suggesting a role in pregnancy progression. Epigenetic regulation of CYP27B1 and CYP24A1 has previously been described in cell and animal models, and despite emerging evidence for a critical role of epigenetics in placentation generally, little is known about the regulation of enzymes modulating vitamin D homeostasis at the fetomaternal interface. In this study, we investigated the methylation status of genes regulating vitamin D bioavailability and activity in the placenta. No methylation of the VDR (vitamin D receptor) and CYP27B1 genes was found in any placental tissues. In contrast, the CYP24A1 gene is methylated in human placenta, purified cytotrophoblasts, and primary and cultured chorionic villus sampling tissue. No methylation was detected in any somatic human tissue tested. Methylation was also evident in marmoset and mouse placental tissue. All three genes were hypermethylated in choriocarcinoma cell lines, highlighting the role of vitaminDderegulation in this cancer. Gene expression analysis confirmed a reduced capacity for CYP24A1 induction with promoter methylation in primary cells and in vitro reporter analysis demonstrated that promoter methylation directly down-regulates basal promoter activity and abolishes vitamin D-mediated feedback activation. This study strongly suggests that epigenetic decoupling of vitamin D feedback catabolism plays an important role in maximizing active vitamin D bioavailability at the fetomaternal interface

    Six weeks of home enteral nutrition versus standard care after esophagectomy or total gastrectomy for cancer: study protocol for a randomized controlled trial

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    Background: Each year approximately 3000 patients in the United Kingdom undergo surgery for esophagogastric cancer. Jejunostomy feeding tubes, placed at the time of surgery for early postoperative nutrition, have been shown to have a positive impact on clinical outcomes in the short term. Whether feeding out of hospital is of benefit is unknown. Local experience has identified that between 15 and 20% of patients required ‘rescue’ jejunostomy feeding for nutritional problems and weight loss while at home. This weight loss and poor nutrition may contribute to the detrimental effect on the overall quality of life (QoL) reported in these patients. Methods/Design: This randomized pilot and feasibility study will provide preliminary information on the routine use of jejunostomy feeding after hospital discharge in terms of clinical benefits and QoL. Sixty participants undergoing esophagectomy or total gastrectomy will be randomized to receive either a planned program of six weeks of home jejunostomy feeding after discharge from hospital (intervention) or treatment-as-usual (control). The intention of this study is to inform a multi-centre randomized controlled trial. The primary outcome measures will be recruitment and retention rates at six weeks and six months. Secondary outcome measures will include disease specific and general QoL measures, nutritional parameters, total and oral nutritional intake, hospital readmission rates, and estimates of healthcare costs. Up to 20 participants will also be enrolled in a qualitative sub-study that will explore participants’ and carers’ experiences of home tube feeding. The results will be disseminated by presentation at surgical, gastroenterological and dietetic meetings and publication in appropriate peer review journals. A patient-friendly lay summary will be made available on the University of Leicester and the University Hospitals of Leicester NHS Trust websites. The study has full ethical and institutional approval and started recruitment in July 2012. Trial registration: UKClinical Research Network ID #12447 (Main study); UKCRN ID#13361 (Qualitative sub study); ClinicalTrials.gov #NCT01870817 (First registered 28 May 2013

    Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

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    Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

    Neonatal Systemic AAV Induces Tolerance to CNS Gene Therapy in MPS I Dogs and Nonhuman Primates

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    The potential host immune response to a nonself protein poses a fundamental challenge for gene therapies targeting recessive diseases. We demonstrate in both dogs and nonhuman primates that liver-directed gene transfer using an adeno-associated virus (AAV) vector in neonates induces a persistent state of immunological tolerance to the transgene product, substantially improving the efficacy of subsequent vector administration targeting the central nervous system (CNS). We applied this approach to a canine model of mucopolysaccharidosis type I (MPS I), a progressive neuropathic lysosomal storage disease caused by deficient activity of the enzyme α-l-iduronidase (IDUA). MPS I dogs treated systemically in the first week of life with a vector expressing canine IDUA did not develop antibodies against the enzyme and exhibited robust expression in the CNS upon intrathecal AAV delivery at 1 month of age, resulting in complete correction of brain storage lesions. Newborn rhesus monkeys treated systemically with AAV vector expressing human IDUA developed tolerance to the transgene, resulting in high cerebrospinal fluid (CSF) IDUA expression and no antibody induction after subsequent CNS gene therapy. These findings suggest that inducing tolerance to the transgene product during a critical period in immunological development can improve the efficacy and safety of gene therapy
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