Splenectomy Normalizes Hematocrit in Murine Polycythemia Vera

Splenic enlargement (splenomegaly) develops in numerous disease states, although a specific pathogenic role for the spleen has rarely been described. In polycythemia vera (PV), an activating mutation in Janus kinase 2 (JAK2V617) induces splenomegaly and an increase in hematocrit. Splenectomy is sparingly performed in patients with PV, however, due to surgical complications. Thus, the role of the spleen in the pathogenesis of human PV remains unknown. We specifically tested the role of the spleen in the pathogenesis of PV by performing either sham (SH) or splenectomy (SPL) surgeries in a murine model of JAK2V617F-driven PV. Compared to SH-operated mice, which rapidly develop high hematocrits after JAK2V617F transplantation, SPL mice completely fail to develop this phenotype. Disease burden (JAK2V617) is equivalent in the bone marrow of SH and SPL mice, however, and both groups develop fibrosis and osteosclerosis. If SPL is performed after PV is established, hematocrit rapidly declines to normal even though myelofibrosis and osteosclerosis again develop independently in the bone marrow. In contrast, SPL only blunts hematocrit elevation in secondary, erythropoietin-induced polycythemia. We conclude that the spleen is required for an elevated hematocrit in murine, JAK2V617F-driven PV, and propose that this phenotype of PV may require a specific interaction between mutant cells and the spleen

What future, which technology? On the problem of describing relevant futures.

Doing research on future and emerging technologies raises a number of significant ontological and epistemological challenges. The fundamental uncertainty of the future, combined with problems of appropriate descriptions of technology in general, render it difficult to come to an appropriate account of the likely shape and use of future technologies. This paper discusses several streams of research that address this issue, including the question of relevant description and context, interpretive flexibility, affordances of technology, and multi-stability of technological trajectories. The paper proposes that some of these problems may be addressed by using a democratic and participative approach to technology research and development. Participative technology assessment is then discussed as an example of an established way of democratically engaging with technology stakeholders during research and development. The paper concludes by discussing the promises and limitations of such a participative approach with regard to the question of understanding and researching future technologies

On the interpretative flexibility of hosted ERP

This paper explores the interpretative flexibility of ERP systems through the study of a project to implement a hosted system for the Central Accounting Department of a large multinational. The paper presents intensive case study data around the decision to implement the system and analyses it in terms of the interpretative flexibility of the system. The paper questions the extent to which technological features of the new system influence the perceived flexibility of the system

A GA-based strategy for the calibration of satellite communication phased array antennas

International audienc

Humic-like substances from agro-industrial residues affect growth and nitrogen assimilation in maize (Zea mays L.) plants

Humic-like substances (HL) extracted from the agro-industrial residues of rape (Brassica napus) (B-HL), castor-oil (Ricinus communis) (R-HL) and flax (Linum usitatissimum) (L-HL), and from a digestate (D-HL) were analyzed for their elemental composition and characterized by FT-IR and 13CNMR spectroscopy. The indoleacetic acid (IAA), total phenol (TP) and flavonoid (FL) content, and their auxin-like activity were also determined. HL were then applied to maize plantlets in order to evaluate their effect on plant growth, nitrogen metabolism, and photosynthesis. Results showed that all the HL had a physiologically active IAA, TP and FL content. HL positively affected the growth of maize with a noticeable increase in leaf biomass. The HL from digestate showed the highest values of glutamine synthethase and glutamate synthase enzyme activity, whereas both L and B-HL were more efficient in affecting the chlorophyll a, b and total carotene content. In conclusion, the biostimulant activity of the four HL varied, but the greater bioactivity of HL from digestate was a result of its high acidity and carbon distribution together with its high IAA and TP content, and high auxin-like activit