Platelet FcγRIIA-induced serotonin release exacerbates the severity of Transfusion-Related Acute Lung Injury in mice

Transfusion-related acute lung injury (TRALI) remains a major cause of transfusion-related fatalities. The mechanism of human antibody-mediated TRALI, especially the involvement of the Fcγ receptors, is not clearly established. Contrary to mice, human platelets are unique in their expression of the FcγRIIA/CD32A receptor, suggesting that our understanding of the pathogenesis of antibody-mediated TRALI is partial, as the current murine models incompletely recapitulate the human immunology. We evaluated the role of FcγRIIA/CD32A in TRALI using a humanized mouse model expressing the FcγRIIA/CD32A receptor. When challenged with a recombinant chimeric human immunoglobulin G1/mouse anti–major histocompatibility complex class I monoclonal antibody, these mice exhibited exacerbated alveolar edema and higher mortality compared with wild-type (WT) mice. Unlike in WT mice, monocytes/macrophages in CD32A(+) mice were accessory for TRALI initiation, indicating the decisive contribution of another cell type. Platelet activation was dramatically increased in CD32A(+) animals, resulting in their increased consumption and massive release of their granule contents. Platelet depletion prevented the exacerbation of TRALI in CD32A(+) mice but did not affect TRALI in WT animals. By blocking platelet serotonin uptake with fluoxetine, we showed that the severity of TRALI in CD32A(+) mice resulted from the serotonin released by the activated platelets. Furthermore, inhibition of 5-hydroxytryptamine 2A serotonin receptor with sarpogrelate, before or after the induction of TRALI, abolished the aggravation of lung edema in CD32A(+) mice. Our findings show that platelet FcγRIIA/CD32A activation exacerbates antibody-mediated TRALI and provide a rationale for designing prophylactic and therapeutic strategies targeting the serotonin pathway to attenuate TRALI in patients

A Study of the Orbits of the Logarithmic Potential for Galaxies

The logarithmic potential is of great interest and relevance in the study of the dynamics of galaxies. Some small corrections to the work of Contopoulos & Seimenis (1990) who used the method of Prendergast (1982) to find periodic orbits and bifurcations within such a potential are presented. The solution of the orbital radial equation for the purely radial logarithmic potential is then considered using the p-ellipse (precessing ellipse) method pioneered by Struck (2006). This differential orbital equation is a special case of the generalized Burgers equation. The apsidal angle is also determined, both numerically as well as analytically by means of the Lambert W and the Polylogarithm functions. The use of these functions in computing the gravitational lensing produced by logarithmic potentials is discussed.Comment: 12 pages, 4 figures. Accepted by MNRAS Sept 6 201

Nonverbal communication interface for collaborative virtual environments

Nonverbal communication is an important aspect of real-life face-to-face interaction and one of the most efficient ways to convey emotions, therefore users should be provided the means to replicate it in the virtual world. Because articulated embodiments are well suited to provide body communication in virtual environments, this paper first reviews some of the advantages and disadvantages of complex embodiments. After a brief introduction to nonverbal communication theories, we present our solution, taking into account the practical limitations of input devices and social science aspects. We introduce our sample of actions and implementation using our VLNET (Virtual Life Network) networked virtual environment and discuss the results of an informal evaluation experimen

Ranger, an Example of Integration of Robotics into the Home Ecosystem

This paper presents the concept and an example of robject, a robotic entity embedded in an everyday object. Robjects use the affordance of the original object to ensure an efficient interaction and a high acceptance. The example of the ranger robot shows that this approach can be applied to the domestic environment. We explore the integration of a robot (robject) into a family household, by regarding the home as a ecosystem, which consists of people, parts, products, activities, and interactions. A test of the ranger robot in families validates this holistic approach and shows the impact of this type of design in respect to the complexity of the robotic system