163 research outputs found

    High Arctic biocrusts: characterization of the exopolysaccharidic matrix

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    Pretransplant active disease status and HLA class II mismatching are associated with increased incidence and severity of cytokine release syndrome after haploidentical transplantation with posttransplant cyclophosphamide

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    Cytokine release syndrome (CRS) represents a life-threatening side effect after haploidentical stem cell transplantation (Haplo-SCT) with posttransplant cyclophosphamide (PT-Cy). Factors predictive of CRS development is still a matter of debate. We retrospectively analyzed 102 consecutive patients receiving a bone marrow (BM) (n = 42) or peripheral blood stem cells (PBSC) (n = 60) Haplo-SCT with PT-Cy. The two cohorts were similar in main patients' characteristics besides disease type (P = .02). Cumulative incidence of grades 1, 2, and 653 CRS was 80%, 52%, and 15% at a median of 2, 4, and 7 days, respectively. Moderate/High-grade fever (39\ub0-41\ub0), grade 1 and grade 653 CRS occurred more frequently after PBSC relative to BM grafts (68% vs 33%, P = .0005; 87% vs 71%, P = .009; 20% vs 7%, P = .07). Only patients experiencing grade 653 CRS had a worse outcome in terms of 1-year overall survival (OS) and nonrelapse mortality (NRM): 39% vs 80% (P = .002) and 40% vs 8% (P = .005), respectively. By univariate analysis the only factors associated with the increased risk of 653 CRS were pretransplant disease status (8% for complete remission, 11% for partial remission, and 38% for active disease, P = .002), HLA-DRB1 mismatching (57% vs 14%, P = .007), and PBSC graft (P = .07). By multivariable analysis, only pretransplant disease status (hazard ratio, HR: 6.84, P = .005) and HLA-DRB1 mismatching (HR: 17.19, P = .003) remained independent predictors of grade 653 CRS. Only grade 653 CRS is clinically relevant for the final outcome of patients receiving Haplo-SCT with PT-Cy, is more frequent after a PBSC graft and is associated with pretransplant active disease and HLA-DRB1 mismatching

    Integrative analysis of the genomic and transcriptomic landscape of double-refractory multiple myeloma

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    In multiple myeloma, novel treatments with proteasome inhibitors (PIs) and immunomodulatory agents (IMiDs) have prolonged survival but the disease remains incurable. At relapse, next-generation sequencing has shown occasional mutations of drug targets but has failed to identify unifying features that underlie chemotherapy resistance. We studied 42 patients refractory to both PIs and IMiDs. Whole-exome sequencing was performed in 40 patients, and RNA sequencing (RNA-seq) was performed in 27. We found more mutations than were reported at diagnosis and more subclonal mutations, which implies ongoing evolution of the genome of myeloma cells during treatment. The mutational landscape was different from that described in published studies on samples taken at diagnosis. The TP53 pathway was the most frequently inactivated (in 45% of patients). Conversely, point mutations of genes associated with resistance to IMiDs were rare and were always subclonal. Refractory patients were uniquely characterized by having a mutational signature linked to exposure to alkylating agents, whose role in chemotherapy resistance and disease progression remains to be elucidated. RNA-seq analysis showed that treatment or mutations had no influence on clustering, which was instead influenced by karyotypic events. We describe a cluster with both amp(1q) and del(13) characterized by CCND2 upregulation and also overexpression of MCL1, which represents a novel target for experimental treatments. Overall, high-risk features were found in 65% of patients. However, only amp(1q) predicted survival. Gene mutations of IMiD and PI targets are not a preferred mode of drug resistance in myeloma. Chemotherapy resistance of the bulk tumor population is likely attained through differential, yet converging evolution of subclones that are overall variable from patient to patient and within the same patient

    On Poincare and logarithmic Sobolev inequalities for a class of singular Gibbs measures

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    This note, mostly expository, is devoted to Poincar{\'e} and log-Sobolev inequalities for a class of Boltzmann-Gibbs measures with singular interaction. Such measures allow to model one-dimensional particles with confinement and singular pair interaction. The functional inequalities come from convexity. We prove and characterize optimality in the case of quadratic confinement via a factorization of the measure. This optimality phenomenon holds for all beta Hermite ensembles including the Gaussian unitary ensemble, a famous exactly solvable model of random matrix theory. We further explore exact solvability by reviewing the relation to Dyson-Ornstein-Uhlenbeck diffusion dynamics admitting the Hermite-Lassalle orthogonal polynomials as a complete set of eigenfunctions. We also discuss the consequence of the log-Sobolev inequality in terms of concentration of measure for Lipschitz functions such as maxima and linear statistics.Comment: Minor improvements. To appear in Geometric Aspects of Functional Analysis -- Israel Seminar (GAFA) 2017-2019", Lecture Notes in Mathematics 225

    The prescribed mean curvature equation in weakly regular domains

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    We show that the characterization of existence and uniqueness up to vertical translations of solutions to the prescribed mean curvature equation, originally proved by Giusti in the smooth case, holds true for domains satisfying very mild regularity assumptions. Our results apply in particular to the non-parametric solutions of the capillary problem for perfectly wetting fluids in zero gravity. Among the essential tools used in the proofs, we mention a \textit{generalized Gauss-Green theorem} based on the construction of the weak normal trace of a vector field with bounded divergence, in the spirit of classical results due to Anzellotti, and a \textit{weak Young's law} for (Λ,r0)(\Lambda,r_{0})-minimizers of the perimeter.Comment: 23 pages, 1 figure --- The results on the weak normal trace of vector fields have been now extended and moved in a self-contained paper available at: arXiv:1708.0139

    The alternative sigma factor SigF is a key player in the control of secretion mechanisms in Synechocystis sp. PCC 6803.

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    Cyanobacterial alternative sigma factors are crucial players in environmental adaptation processes, which may involve bacterial responses related to maintenance of cell envelope and control of secretion pathways. Here, we show that the Group 3 alternative sigma factor F (SigF) plays a pleiotropic role in Synechocystis sp. PCC 6803 physiology, with a major impact on growth and secretion mechanisms, such as the production of extracellular polysaccharides, vesiculation and protein secretion. Although ΔsigF growth was significantly impaired, the production of released polysaccharides (RPS) increased 3 to 4-fold compared to the wild-type. ΔsigF exhibits also impairment in formation of outer-membrane vesicles (OMVs) and pili, as well as several other cell envelope alterations. Similarly, the exoproteome composition of ΔsigF differs from the wild-type both in amount and type of proteins identified. Quantitative proteomics (iTRAQ) and an in silico analysis of SigF binding motifs revealed possible targets/pathways under SigF control. Besides changes in protein levels involved in secretion mechanisms, our results indicated that photosynthesis, central carbon metabolism, and protein folding/degradation mechanisms are altered in ΔsigF. Overall, this work provided new evidences about the role of SigF on Synechocystis physiology and associates this regulatory element with classical and non-classical secretion pathways

    Trisonomia 9 in pazienti affetti da MPN PH-: aspetti clinici e laboratoristici

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    Le neoplasie mieloproliferative ( MPN), comprendenti la Policitemia vera (PV), la Trombocitemia essenziale (TE) e la Mielofibrosi idiopatica (MFI), sono disordini clonali Philadelphia negativi caratterizzati, nel 20% dei casi, da anomalie cromosomiche ricorrenti. La trisomia 9 rappresenta la seconda anomalia cromosomica pi\uf9 frequente nelle MPN dopo la delezione 20q. Abbiamo eseguito l\u2019analisi citogenetica su aspirato midollare di una casistica monocentrica di 325 pazienti affetti da MPN; tutti i pazienti sono risultati Ph-, la trisomia 9 \ue8 stata riscontrata in 13 pazienti (9 affetti da PV e 4 da TE), in 10 casi come unica anomalia cromosomica, in un caso associata a trisomia 8 e in 2 casi in un cariotipo pi\uf9 complesso. Sono state analizzate le caratteristiche cliniche e di laboratorio e l\u2019evoluzione di malattia, al fine di individuare se tale anomalia citogenetica avesse delle particolari stigmate. I pazienti sono stati seguiti regolarmente per un periodo medio di 10,6 anni (range 1- 23 anni). L\u2019et\ue0 media alla diagnosi era 62 anni e il rapporto M:F di 1,2:1. I dati di laboratorio mostravano un valore medio di emoglobina di 16,7 g/dl, un numero medio di globuli bianchi di 9657/mmc, mentre la conta piastrinica media era di 690000/mmc. Il dosaggio dell\u2019 eritropoietina serica \ue8 risultato ridotto in tutti i pazienti e tutti presentavano la mutazione JAK2 V617F (carica allelica media 47,1%). E\u2019 interessante notare che nei pazienti affetti da TE, i valori di emoglobina alla diagnosi, pur non essendo sufficienti per porre diagnosi di PV erano comunque ai limiti superiori di norma. Dei 4 pazienti con TE, 3 (75%) sono evoluti a distanza di anni in PV, evento relativamente raro. I dati ottenuti evidenziano una maggior frequenza della trisomia 9 nei pazienti con PV rispetto alle altre neoplasie mieloproliferative ed inoltre sottolineano come i pazienti con TE portatori di tale alterazione citogenetica, abbiano un fenotipo simil-PV e un aumentato rischio di evoluzione in franca PV. Non \ue8 stata osservata trisomia 9 nelle Mielofibrosi. E\u2019 inoltre da segnalare che sul braccio corto del cromosoma 9 \ue8 stato mappato il gene JAK-2, gene che risulta mutato frequentemente nelle MPN Ph- e soprattutto nelle PV di cui rappresenta un marker molecolare

    Characterization of Generalized Young Measures Generated by Symmetric Gradients

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    This work establishes a characterization theorem for (generalized) Young measures generated by symmetric derivatives of functions of bounded deformation (BD) in the spirit of the classical Kinderlehrer\ue2\u80\u93Pedregal theorem. Our result places such Young measures in duality with symmetric-quasiconvex functions with linear growth. The \ue2\u80\u9clocal\ue2\u80\u9d proof strategy combines blow-up arguments with the singular structure theorem in BD (the analogue of Alberti\ue2\u80\u99s rank-one theorem in BV), which was recently proved by the authors. As an application of our characterization theorem we show how an atomic part in a BD-Young measure can be split off in generating sequences

    Metagenomic and Metabolic Profiling of Nonlithifying and Lithifying Stromatolitic Mats of Highborne Cay, The Bahamas

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    BACKGROUND: Stromatolites are laminated carbonate build-ups formed by the metabolic activity of microbial mats and represent one of the oldest known ecosystems on Earth. In this study, we examined a living stromatolite located within the Exuma Sound, The Bahamas and profiled the metagenome and metabolic potential underlying these complex microbial communities. METHODOLOGY/PRINCIPAL FINDINGS: The metagenomes of the two dominant stromatolitic mat types, a nonlithifying (Type 1) and lithifying (Type 3) microbial mat, were partially sequenced and compared. This deep-sequencing approach was complemented by profiling the substrate utilization patterns of the mats using metabolic microarrays. Taxonomic assessment of the protein-encoding genes confirmed previous SSU rRNA analyses that bacteria dominate the metagenome of both mat types. Eukaryotes comprised less than 13% of the metagenomes and were rich in sequences associated with nematodes and heterotrophic protists. Comparative genomic analyses of the functional genes revealed extensive similarities in most of the subsystems between the nonlithifying and lithifying mat types. The one exception was an increase in the relative abundance of certain genes associated with carbohydrate metabolism in the lithifying Type 3 mats. Specifically, genes associated with the degradation of carbohydrates commonly found in exopolymeric substances, such as hexoses, deoxy- and acidic sugars were found. The genetic differences in carbohydrate metabolisms between the two mat types were confirmed using metabolic microarrays. Lithifying mats had a significant increase in diversity and utilization of carbon, nitrogen, phosphorus and sulfur substrates. CONCLUSION/SIGNIFICANCE: The two stromatolitic mat types retained similar microbial communities, functional diversity and many genetic components within their metagenomes. However, there were major differences detected in the activity and genetic pathways of organic carbon utilization. These differences provide a strong link between the metagenome and the physiology of the mats, as well as new insights into the biological processes associated with carbonate precipitation in modern marine stromatolites
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