Epigenetic abnormalities in myeloproliferative neoplasms: a target for novel therapeutic strategies

The myeloproliferative neoplasms (MPNs) are a group of clonal hematological malignancies characterized by a hypercellular bone marrow and a tendency to develop thrombotic complications and to evolve to myelofibrosis and acute leukemia. Unlike chronic myelogenous leukemia, where a single disease-initiating genetic event has been identified, a more complicated series of genetic mutations appear to be responsible for the BCR-ABL1-negative MPNs which include polycythemia vera, essential thrombocythemia, and primary myelofibrosis. Recent studies have revealed a number of epigenetic alterations that also likely contribute to disease pathogenesis and determine clinical outcome. Increasing evidence indicates that alterations in DNA methylation, histone modification, and microRNA expression patterns can collectively influence gene expression and potentially contribute to MPN pathogenesis. Examples include mutations in genes encoding proteins that modify chromatin structure (EZH2, ASXL1, IDH1/2, JAK2V617F, and IKZF1) as well as epigenetic modification of genes critical for cell proliferation and survival (suppressors of cytokine signaling, polycythemia rubra vera-1, CXC chemokine receptor 4, and histone deacetylase (HDAC)). These epigenetic lesions serve as novel targets for experimental therapeutic interventions. Clinical trials are currently underway evaluating HDAC inhibitors and DNA methyltransferase inhibitors for the treatment of patients with MPNs

Conceptual hydrological model for an average-sized catchment area, I. Concepts and relationships

Abstract. The model enables the calculation, in daily values, of water transfers (interception by vegetation, evapotranspiration, surface runoff, infiltration, percolation, etc.) of the state of the different phases of the water cycle (water accumulated in the snow cover, in the vegetative cover, on the surface, in the zone of aeration and in the zone of saturation of the soil, etc.) and of the flow at the outlet of the area (surface runoff, interflow and base flow). The aim of this model is to establish a detailed water balance of a catchment area, to follow its daily evolution and to understand the factors that determine its nature.This work sets out the concepts and justifies the mathematical functions and relationships used. A next publication will be devoted to the determination of parameters, the validity of the model and its applications.info:eu-repo/semantics/publishe

Le bac évaporatoire en usage dans le réseau hydrométéorologique belge

SUMMARY.The evaporation tank consists of a square pan with a flat base, 2 metres long and 0, 7 metre deep, set into the ground with the rim 0, 1 metre above, and connected to a well on which is installed a limnigraph. This limnigraph records continuously fluctuations of the free water surface.The recordings show that a large amount of water can be evaporated during rainfall. This phenomenon is specific at every evaporation tank with a free water surface. It is only during the dry intervals that a strong correlation can be established between the evaporation measured in the tank and the potential evapotranspiration of the surrounding natural surfaces. In order to locate the dry intervals and to measure the evaporation only during these intervals, it is necessary to use an apparatus provided with a continuous recording mechanismRÉSUMÉ.Le bac évaporatoire est constitué d'une cuve carrée, à fond plat, de 2 m de côté et de 0, 7 m de pro-fondeur, enterée jusqu'à 0, 1 m du bord supérieur et reliée à un puits sur lequel est installé un limni-graphe. Ce limnigraphe fournit un enregistrement continu des variations de niveau de la nappe d'eau libre.Les enregistrements montrent que la quantité d'eau évaporée pendant les épisodes pluvieux peut être importante. Ce phénomène est propre à tout bac évaporatoire à nappe d'eau libre. Ce n'est donc qu'au cours des intervalles sees qu'il. peut exister une corrélation étroite entre l'évaporation mesurée au bac et l'évapotranspiration potentielle des surfaces naturelles avoisinantes. Pour détecter aisément les intervalles secs et mesurer l'éyaporation au cours de ces seuls intervalles, il est indispensable de recourir à un appareil muni d'un dispositif d'enregistrement continu.info:eu-repo/semantics/publishe

L'évaporation d'un bac d'eau libre - sa signification restreinte

info:eu-repo/semantics/publishe

Comparaison d'instruments de mesure de l'humidité de l'air sous abri

Résumé.Le psychrographe et le psychromètre d'August peuvent fournir des valeurs instantanées de l'humidité de l'air avec une précision suffisante à condition d'adopter un coefficient psychrométrique adéquat. Dans les conditions de ventilation naturelle de l'abri utilisé dans le réseau hydrométéorologique, celui-ci vaut 0,720.Pour évaluer avec précision les moyennes journalières de l'humidité de l'air, il est recommandable de recourir au psychrographe, instrument enregistreur, plutôt qu'aux psychromètres d'Assmann et d'August. Il s'avère enfin que le psychrographe est aussi beaucoup plus stable et plus précis que le thermohygrographe. Ce dernier ne devrait donc être utilisé que comme instrument d'appoint durant les périodes de gel.Summary.The psychrograph and the August psychrometer can deliver with sufficient precision instantaneous values of the air moisture provided an adequate psychrometric coefficient is adopted. With natural ventilation inside the shelter used in the hydrometeorological network this coefficient is equal to 0.720.In order to have a precise estimate of the daily averages of air moisture, it is recommended to use the psychrograph, which is a recorder, rather than the Assmann and August psychrometers. moreover, it is established that the psychrograph is more stable and more precise than the thermohygrograph. This last one should therefore be used only during the freezing periods.info:eu-repo/semantics/publishe