18 research outputs found

    A prominent lack of IgG1-Fc fucosylation of platelet alloantibodies in pregnancy.

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    To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Immunoglobulin G (IgG) formed during pregnancy against human platelet antigens (HPAs) of the fetus mediates fetal or neonatal alloimmune thrombocytopenia (FNAIT). Because antibody titer or isotype does not strictly correlate with disease severity, we investigated by mass spectrometry variations in the glycosylation at Asn297 in the IgG Fc because the composition of this glycan can be highly variable, affecting binding to phagocyte IgG-Fc receptors (FcγR). We found markedly decreased levels of core fucosylation of anti-HPA-1a-specific IgG1 from FNAIT patients (n = 48), but not in total serum IgG1. Antibodies with a low amount of fucose displayed higher binding affinity to FcγRIIIa and FcγRIIIb, but not to FcγRIIa, compared with antibodies with a high amount of Fc fucose. Consequently, these antibodies with a low amount of Fc fucose showed enhanced phagocytosis of platelets using FcγRIIIb(+) polymorphonuclear cells or FcγRIIIa(+) monocytes as effector cells, but not with FcγRIIIa(-) monocytes. In addition, the degree of anti-HPA-1a fucosylation correlated positively with the neonatal platelet counts in FNAIT, and negatively to the clinical disease severity. In contrast to the FNAIT patients, no changes in core fucosylation were observed for anti-HLA antibodies in refractory thrombocytopenia (post platelet transfusion), indicating that the level of fucosylation may be antigen dependent and/or related to the immune milieu defined by pregnancy.Sanquin/PPOC-09- 025 Landsteiner Foundation for Blood Transfusion/0721 info:eu-repo/grantAgreement/EC/FP7/27853

    Collisional and Radiative Processes in Optically Thin Plasmas

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    Most of our knowledge of the physical processes in distant plasmas is obtained through measurement of the radiation they produce. Here we provide an overview of the main collisional and radiative processes and examples of diagnostics relevant to the microphysical processes in the plasma. Many analyses assume a time-steady plasma with ion populations in equilibrium with the local temperature and Maxwellian distributions of particle velocities, but these assumptions are easily violated in many cases. We consider these departures from equilibrium and possible diagnostics in detail

    Cetaceans in the global centre of marine biodiversity

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    Indonesia has a diverse range of cetacean species, yet there are few records of their distribution, especially from remote regions. Incidental sightings from aerial surveys were conducted in 2006 and boat-based surveys were conducted from 2006–2011 in Raja Ampat in the Bird's Head Seascape, Indonesia. This paper is the first to provide a species list and an indication of the spatial and temporal distribution of cetaceans in central and southern Raja Ampat. Seven dolphin and six whale species were documented, including Indo-Pacific humpback dolphins Sousa chinensis, Bryde's Balaenoptera edeni, sperm Physeter macrocephalus, killer Orcinus orca and pygmy killer Feresa attenuata whales. Temporal differences in sightings suggest Raja Ampat is an important area for migratory whale species and resident populations of Indo-Pacific humpback Sousa chinensis, spinner Stenella longirostris and common bottlenose Tursiops truncatus dolphins. Cetacean diversity was highest in the months of January–February, May and October–November, with most sightings recorded in Kofiau marine protected area and Dampier and Sagewin Straits. Diversity and species distribution data are critical for managing cetaceans in Indonesia. Emerging threats to cetaceans in Raja Ampat include seismic surveys for seabed oil and gas exploration, potential strikes from increasing ship traffic, entanglement in fishing nets and increasing discharge of plastic pollution from urban areas. In addition to regulations for marine protected areas, a wider conservation strategy is required to address or better manage emerging threats to Raja Ampat, and to ensure the long-term protection of resident and migratory dolphin and whale species
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