Informed Consent Versus Presumed Consent The Role of the Family in Organ Donations

Two types of legislation underlie cadaveric organ donations: presumed consent (PC) and informed consent (IC). In informed consent countries, people are only donors when deceased if they registered to do so while alive. Conversely, in presumed consent countries, anybody is a potential donor when deceased. People have thus to register if they do not want to donate their body. PC has always been perceived as the “best” system for society in terms of organ donations whereas IC is supposed to be more ethical. However, in both systems, the family has a say, especially for the deceased who did not sign anything while alive. Taking the family decision into account, we show that the previous results may be reversed. The difference between both systems resides in the way an individual can commit to his/her will, eventually against the opinion of his/her family. IC can dominate PC in terms of organ donations whereas PC can be a more ethical system. In the general case, two opposite effects are at stake and the result depends on the extent to which people stay in the default situation. We discuss several causes of inactions (death taboo, procrastination, anticipated regret,...) and their impact on both the individual and the family.

Detailed plan for the COMET WP3 initial research activity - list of research projects and goals, participants and timing

Detailed plan for the COMET Work Package (WP) 3

Rab27a and Rab27b control different steps of the exosome secretion pathway

Exosomes are secreted membrane vesicles that share structural and biochemical characteristics with intraluminal vesicles of multivesicular endosomes (MVEs). Exosomes could be involved in intercellular communication and in the pathogenesis of infectious and degenerative diseases. The molecular mechanisms of exosome biogenesis and secretion are, however, poorly understood. Using an RNA interference (RNAi) screen, we identified five Rab GTPases that promote exosome secretion in HeLa cells. Among these, Rab27a and Rab27b were found to function in MVE docking at the plasma membrane. The size of MVEs was strongly increased by Rab27a silencing, whereas MVEs were redistributed towards the perinuclear region upon Rab27b silencing. Thus, the two Rab27 isoforms have different roles in the exosomal pathway. In addition, silencing two known Rab27 effectors, Slp4 (also known as SYTL4, synaptotagmin-like 4) and Slac2b (also known as EXPH5, exophilin 5), inhibited exosome secretion and phenocopied silencing of Rab27a and Rab27b, respectively. Our results therefore strengthen the link between MVEs and exosomes, and introduce ways of manipulating exosome secretion in vivo

Bmcc1s, a Novel Brain-Isoform of Bmcc1, Affects Cell Morphology by Regulating MAP6/STOP Functions

The BCH (BNIP2 and Cdc42GAP Homology) domain-containing protein Bmcc1/Prune2 is highly enriched in the brain and is involved in the regulation of cytoskeleton dynamics and cell survival. However, the molecular mechanisms accounting for these functions are poorly defined. Here, we have identified Bmcc1s, a novel isoform of Bmcc1 predominantly expressed in the mouse brain. In primary cultures of astrocytes and neurons, Bmcc1s localized on intermediate filaments and microtubules and interacted directly with MAP6/STOP, a microtubule-binding protein responsible for microtubule cold stability. Bmcc1s overexpression inhibited MAP6-induced microtubule cold stability by displacing MAP6 away from microtubules. It also resulted in the formation of membrane protrusions for which MAP6 was a necessary cofactor of Bmcc1s. This study identifies Bmcc1s as a new MAP6 interacting protein able to modulate MAP6-induced microtubule cold stability. Moreover, it illustrates a novel mechanism by which Bmcc1 regulates cell morphology

La grenouille qui se peut faire aussi grosse que le boeuf

Quite often, a firm has to decide between investing in a safe project ("small") where rewards and losses remain moderate and a risky alternative ("big") where the rewards and the losses are larger. We study such a choice in a context where the probability of success depends both on the intrinsic ability of the firm and on the choice of an other firm which is a follower. The ability of the follower is unknown to the leader and vice-versa. We show that a leader with a poor ability selects the big project as well as a leader with a very high ability. On the other hand a leader with a medium ability prefers the small project. When weak the follower chooses the small project, when of medium ability it chooses randomly and when of high ability it selects the big project. informatio asymmetry, though, prevents the selection of the best firm: a leader with a lower ability can deter competition form a medium or weak follower by selecting the big project.

Identification of Mixture Models Using Support Variations

We consider the issue of identifying nonparametrically mixture models. In thesemodels, all observed variables depend on a common and unobserved component,but are mutually independent conditional on it. Such models are important in themeasurement error, auction and matching literatures. Traditional approaches relyon parametric assumptions or strong functional restrictions. We show that thesemodels are actually identified nonparametrically if a moving support assumption issatisfied. More precisely, we suppose that the supports of the observed variables movewith the true value of the unobserved component. We show that this assumption istheoretically grounded, empirically relevant and testable. Finally, we compare ourapproach with the diagonalization technique introduced by Hu and Schennach (2008),which allows to obtain similar results.

Testing for Asymmetric Information in the Viager Market

A viager real estate transaction consists in selling a property in return for a down paymentand a rent (life annuity) that the buyer has to pay until the seller dies. This paper testsfor the presence of asymmetric information in this market. Thanks to a no arbitrage condition(buyers must be indifferent between purchasing on the standard and viager market), weidentify the type of the seller as a sum of weighted death probabilities. By comparing thesesums with analogously defined national-level sums we can check whether viager sellers havethe same survival distribution as individuals in the population. We then develop a modelfor a viager sale and derive testable predictions under symmetric and asymmetric information.Our test for asymmetric information consists in regressing the contract parameters(down payment and rent) on the inferred type of the seller, and comparing the estimateswith the predicted outcomes. Notarial data are used on transactions in Paris between 1992and 2001. We find that sellers do not have the same survival distributions as comparablepersons in the population, and hence they have information about their death probabilities.The hypothesis that information is symmetrically distributed between buyers and sellers isaccepted. This highlights that the information about the seller’s survival prospects is nolonger private when the contract is signed.

Metallic nanoparticle chains on dielectric waveguides: coupled and uncoupled situations compared

International audienceWe investigate the optical behaviors of metallic nanoparticle (MNP) chains supporting localized surface plasmon (LSP) for different distances between particles. MNPs are excited through the fundamental TE mode of a silicon waveguide. Finite difference time domain (FDTD) calculations and optical power transmission measurements reveal three different behaviors. For short distances between particles, dipolar coupling occurs, and the MNP chain behaves as a waveguide. For the longest distances, nanoparticles are uncoupled, and the MNP chain acts as a LSP Bragg grating. Finally, for intermediate distances, we observe one behavior at a time, i.e. dipolar coupling or LSP Bragg reflection. There is only a small range of wavelengths within which both behaviors can coexist