Chaotic genetic structure and past demographic expansion of the invasive gastropod Tritia neritea in its native range, the Mediterranean Sea

To better predict population evolution of invasive species in introduced areas it is critical to identify and understand the mechanisms driving genetic diversity and structure in their native range. Here, we combined analyses of the mitochondrial COI gene and 11 microsatellite markers to investigate both past demographic history and contemporaneous genetic structure in the native area of the gastropod Tritia neritea, using Bayesian skyline plots (BSP), multivariate analyses and Bayesian clustering. The BSP framework revealed population expansions, dated after the last glacial maximum. The haplotype network revealed a strong geographic clustering. Multivariate analyses and Bayesian clustering highlighted the strong genetic structure at all scales, between the Black Sea and the Adriatic Sea, but also within basins. Within basins, a random pattern of genetic patchiness was observed, suggesting a superimposition of processes involving natural biological effects (no larval phase and thus limited larval dispersal) and putative anthropogenic transport of specimens. Contrary to the introduced area, no isolation-by-distance patterns were recovered in the Mediterranean or the Black Seas, highlighting different mechanisms at play on both native and introduced areas, triggering unknown consequences for species’ evolutionary trajectories. These results of Tritia neritea populations on its native range highlight a mixture of ancient and recent processes, with the effects of paleoclimates and life history traits likely tangled with the effects of human-mediated dispersal.

Propofol-induced hyperamylasaemia in a general intensive care unit

This study examined the incidence of hyperamylasaemia, in the absence of other plausible causes of pancreatic dysfunction, in intensive care unit (ICU) patients who received propofol. One-hundred-and-seventy-two consecutive patients of a general ICU who stayed for more than 24 hours were studied. Patients with a diagnosis consistent with elevated serum amylase levels at admission were excluded from the study, as were patients who had received medications known to raise serum amylase levels. Forty-four patients 53 +/- 20 years of age and median duration of ICU stay of five days (range two to 55) were eligible. Thirty of those, aged 54 +/- 21 years and median duration of ICU stay of five days (range two to 27) received continuous infusion of propofol for sedation (maximum dose 45 microg/kg/min). Of the 30 patients who received propofol, 16 (53%) developed hyperamylasaemia (125 to 466 IU/l) after two to nine days of continuous infusion. Liver and kidney function remained normal throughout the observation period. Of the 14 patients who did not receive propofol (aged 51 +/- 18 years), only two (14%) developed hyperamylasaemia, a significantly lower incidence (P = 0.021). Propofol infusion is associated with biochemical evidence of pancreatic injury. Amylase levels monitoring of propofol-sedated patients is warranted.