Internal carotid arterial canal size and scaling in Euarchonta: Re-assessing implications for arterial patency and phylogenetic relationships in early fossil primates.

Primate species typically differ from other mammals in having bony canals that enclose the branches of the internal carotid artery (ICA) as they pass through the middle ear. The presence and relative size of these canals varies among major primate clades. As a result, differences in the anatomy of the canals for the promontorial and stapedial branches of the ICA have been cited as evidence of either haplorhine or strepsirrhine affinities among otherwise enigmatic early fossil euprimates. Here we use micro X-ray computed tomography to compile the largest quantitative dataset on ICA canal sizes. The data suggest greater variation of the ICA canals within some groups than has been previously appreciated. For example, Lepilemur and Avahi differ from most other lemuriforms in having a larger promontorial canal than stapedial canal. Furthermore, various lemurids are intraspecifically variable in relative canal size, with the promontorial canal being larger than the stapedial canal in some individuals but not others. In species where the promontorial artery supplies the brain with blood, the size of the promontorial canal is significantly correlated with endocranial volume (ECV). Among species with alternate routes of encephalic blood supply, the promontorial canal is highly reduced relative to ECV, and correlated with both ECV and cranium size. Ancestral state reconstructions incorporating data from fossils suggest that the last common ancestor of living primates had promontorial and stapedial canals that were similar to each other in size and large relative to ECV. We conclude that the plesiomorphic condition for crown primates is to have a patent promontorial artery supplying the brain and a patent stapedial artery for various non-encephalic structures. This inferred ancestral condition is exhibited by treeshrews and most early fossil euprimates, while extant primates exhibit reduction in one canal or another. The only early fossils deviating from this plesiomorphic condition are Adapis parisiensis with a reduced promontorial canal, and Rooneyia and Mahgarita with reduced stapedial canals.

An Economic Analysis of Global Policy Proposals to Prohibit Compensation of Blood Plasma Donors

© 2016 International Journal of the Economics of Business.Human blood plasma and its derivative therapies have been used therapeutically for more than 50 years, after first being widely used to treat injuries during World War II. In certain countries, manufacturers of these therapies – known as plasma-derived medicinal products (PDMPs) – compensate plasma donors, raising healthcare and ethical concerns among some parties. In particular, the World Health Organization has taken a strong advocacy position that compensation for blood donations should be eliminated worldwide. This review evaluates the key economic factors underlying the supply and demand for PDMPs and the evidence pointing to the policy options that are most likely to maintain a reliable supply of life-sustaining therapies. It concludes that compensated plasma donation is important for maintaining adequate and consistent supplies of plasma and limits the risk of under-treatment for the foreseeable future.