Proteins involved in the Vroman effect during exposure of human blood plasma to glass and polyethylene

The amounts of fibrinogen adsorbed to glass from various human blood plasmas have been measured as a function of time. The plasmas were 11 single donor plasmas, pooled plasma, a single donor high molecular weight kininogen (HMWK)-deficient plasma and HMWK-deficient plasma, which had been reconstituted with HMWK. For adsorption times between 1 min and 1 h more fibrinogen adsorbed from HMWK-deficient plasma compared with the amounts of fibrinogen which adsorbed from the other plasmas. This result supports the conclusion of several authors that HMWK is involved in the displacement of fibrinogen, initially adsorbed from normal human plasma to glass. Glass surfaces, pre-exposed to solutions of plasma and subsequently exposed to 1:1 diluted plasma, gives rise to a relatively high adsorption of HMWK which is independent of the plasma concentration of the precoating solution. The results indicate that HMWK from 1:1 diluted plasma is involved in the displacement of proteins from glass surfaces which had been pre-exposed to solutions with a low plasma concentration. Experiments with polyethylene as a substrate reveal that high density lipoprotein (HDL) from 1:1 diluted plasma is involved in the displacement of proteins from polyethylene surfaces which had been pre-exposed to solutions with a low plasma concentration. Moreover, evidence is presented that substantial amounts of albumin and fibrinogen, adsorbed from 1:1000 diluted plasma to glass and polyethylene, are displaced from the surfaces of these materials by proteins from 1:1 diluted plasma different from HMWK and HDL

The last word on the wage curve?

In the last decade we have seen extensive international research on the extent to which wages of individuals respond to changing local labour market conditions. For many countries and periods, an inverse relationship between wages and unemployment rates has been found. Following Blanchflower and Oswald (1990), this relationship is referred to as the wage curve. The elasticity of this wage curve has been reported to be so similar across studies, at a level of about -0.1, that Card (1995) called it an empirical law of economics. However, there is considerable heterogeneity among wage curve studies. This paper carries out modern meta-analytic techniques on a sample of 208 elasticities derived from the literature to uncover the reasons for the differences in empirical results across studies. It is found that the wage curve is a robust empirical phenomenon, but there is also clear evidence of downward publication bias. In addition, many reported t statistics are biased upwards due to the use of aggregate unemployment rates and other labour market characteristics for groups. A maximum likelihood method and a trimming procedure are used to correct for these biases. Both methods give similar results for our sample. An unbiased estimate of the wage curve elasticity is about -0.07