Therapeutical potential of direct thrombin inhibitors for atherosclerotic vascular disease

Adverse cardiovascular events are the consequence of a molecular chain reaction at the site of vulnerable plaques. Key players are platelets and coagulation factors that are activated following plaque rupture and often cause arterial obstruction. Thrombin, a plasma serine protease, plays a role in hemostasis of coagulation as well as in thrombosis and cell growth, leading to restenosis and atherosclerosis. Interesting and promising new molecules, the direct thrombin inhibitors, have been shown to be as effective as the combination of glycoprotein IIb-IIIa inhibitors and heparin for the prevention of arterial thrombosis. Until recently, direct thrombin inhibitors could be applied only parenterally; therefore, therapy was limited to hospitalized patients. As a result of recent drug development, orally active direct thrombin inhibitors are now available and have been evaluated for the long-term treatment of venous thrombosis and arterial fibrillation. Due to their specific pharmacodynamic characteristics by binding directly to thrombin--and thus inhibiting platelet aggregation and fibrin generation--these novel drugs may also have therapeutic potential for the treatment of atherothrombotic disease and its complications such as myocardial infarction, stroke or limb ischemia.

Temporal genetic structure and relatedness in the Tufted Duck Aythya fuligula suggests limited kin association in winter

Conspecific aggregation of waterfowl in winter is a common example of animal flocking behaviour, yet patterns of relatedness and temporal substructure in such social groups remain poorly understood even in common species. A previous study based on mark-recapture data showed that Tufted Ducks Aythya fuligula caught on the same day were re-caught together in subsequent winters more often than expected by chance, suggesting stable assortments of ‘socially familiar’ individuals between wintering periods. The genetic relationships within these social groups were not clear. Based on 191 individuals genotyped at 10 microsatellite markers, we investigated the temporal genetic structure and patterns of relatedness among wintering Tufted Ducks at Lake Sempach, Switzerland, in two consecutive winters. We found no evidence of genetic differentiation between temporal groups within or between winters. The average levels of relatedness in temporal groups were low and not higher than expected in random assortments of individuals. However, Mantel tests performed for each sex separately revealed significant negative correlations between the pairwise relatedness coefficients and the number of days between the capture dates of pairs of wintering Tufted Duck in males and females. This pattern suggests the presence of a small number of co-migrating same-sex sibling pairs in wintering flocks of Tufted Ducks. Our findings provide one of the first genetic analyses of a common duck species outside the breeding season and contribute to the understanding of social interactions in long-distance migratory birds.