Structural and functional characterization of an egg-laying hormone signaling system in a lophotrochozoan - The pacific oyster (Crassostrea gigas).

The egg-laying hormones (ELHs) of gastropod mollusks were characterized more than forty years ago. Yet, they have remained little explored in other mollusks. To gain insights into the functionality of the ELH signaling system in a bivalve mollusk - the oyster Crassostrea gigas, this study investigates the processing of its ELH precursor (Cragi-ELH) by mass spectrometry. Some of the ELH mature peptides identified in this study were subsequently investigated by nuclear magnetic resonance and shown to adopt an extended alpha-helix structure in a micellar medium mimicking the plasma membrane. To further characterize the ELH signaling system in C. gigas, a G protein-coupled receptor phylogenetically related to ecdysozoan diuretic hormone DH44 and corticotropin-releasing hormone (CRH) receptors named Cragi-ELHR was also characterized functionally and shown to be specifically activated by the two predicted mature ELH peptides and their N-terminal fragments. Both Cragi-ELH and Cragi-ELHR encoding genes were mostly expressed in the visceral ganglia (VG). Cragi-ELH expression was significantly increased in the VG of both fully mature male and female oysters at the spawning stage. When the oysters were submitted to a nutritional or hyposaline stress, no change in the expression of the ligand or receptor genes was recorded, except for Cragi-ELHR only during a mild acclimation episode to brackish water. These results suggest a role of Cragi-ELH signaling in the regulation of reproduction but not in mediating the stress response in our experimental conditions.

Gonadotropin-inhibitory hormone in teleosts: New insights from a basal representative, the eel.

Since its discovery in birds, gonadotropin-inhibitory hormone (GnIH) has triggered investigation in the other groups of vertebrates. In the present study, we have identified a single gnih gene in the European eel (Anguilla anguilla), a representative species of a basal group of teleosts (Elopomorphs). We have also retrieved a single gnih gene in Osteoglossomorphs, as well as in more recently emerged teleosts, Clupeocephala. Phylogeny and synteny analyses allowed us to infer that one of the two gnih paralogs emerged from the teleost-specific whole genome duplication (TWGD or 3R), would have been lost shortly after the 3R, before the emergence of the basal groups of teleosts. This led to the presence of a single gnih in extant teleosts as in other vertebrates. Two gnih paralogs were still found in some teleost species, such as in salmonids, but resulting from the additional whole genome duplication that specifically occurred in this lineage (4R). Eel gnih was mostly expressed in the diencephalon part of the brain, as analyzed by quantitative real-time PCR. Cloning of eel gnih cDNA confirmed that the sequence of the GnIH precursor encoded three putative mature GnIH peptides (aaGnIH-1, aaGnIH-2 and aaGnIH-3), which were synthesized and tested for their direct effects on eel pituitary cells in vitro. Eel GnIH peptides inhibited the expression of gonadotropin subunits (lhß, fshß, and common a-subunit) as well as of GnRH receptor (gnrh-r2), with no effect on tshß and gh expression. The inhibitory effect of GnIH peptides on gonadotropic function in a basal teleost is in agreement with an ancestral inhibitory role of GnIH in the neuroendocrine control of reproduction in vertebrates.

Medico-economic study of the management of hepatocellular carcinoma by chemo-embolization.

PURPOSE: This study has two aims. The first is to compare conventional lipiodol chemo-embolization (Trans Arterial Chemo-Embolization - TACE) to one using pre-loaded particles (Trans Arterial Chemo-Embolisation-Drug Eluted Bead - TACE-DEB) using a cost minimization study. The second is to define the fundable nature of TACE-DEB and the conditions under which it is cost-effective. MATERIALS AND METHODS: Retrospective study of patients treated by chemo-embolization (n=31: TACE; n=32: TACE-DEB) during the year 2010. The cost minimization study was conducted from the hospital perspective. Direct medical costs were calculated and compared using the readjusted ENCC (National Studies of Costs by Common Methodology) method. The affordability of the two techniques and definition of a cost-effective hypothesis (break-even point) were also established. RESULTS: All DRGs combined, lengths of stay (TACE: 4.90 ± 3.36; TACE-DEB: 5.03 ± 3.36) does not change significantly. An average upper mean cost for TACE-DEB is described (TACE: 2869.05 €; TACE-DEB: 3960.10 €). The affordability calculations in the study show that, overall, TACE-DEB can be funded regardless of DRG. A ratio of 1.3 procedures using the conventional (TACE) method would enable TACE-DEB procedures to be funded. CONCLUSION: This medico-economic analysis demonstrates that the TACE-DEB procedure is fundable.