Validation of technique of measurement of phagocytic clearance of Tc-99m labelled (Nanocoll®) microaggregated human albumin To determine reticuloendothelial system (RES) phagocytosis activity and liver phagocytic function respectively we will measure plasma clearance of 99mTc labelled micro-aggregated human albumin without any imaging studies. It has been shown in several studies that this is a reliable method to estimate RES phagocytosis activity. By measuring the plasma radioactivity disappearance rate instead of doing imaging studies a radioactivity dose of less than 15 MBq is sufficient to determine 99mTc plasma clearance accurately. Disappearance of 99mTc blood activity will be measured serially at 3-minutes intervals to 30 minutes, at 10-minutes intervals to 60 minutes and at 20-minutes intervals to 120 minutes. Three half-life times required for the 99mTc albumin microspheres counting rate to fall from 100% to 50%, from 50% to 25% and from 25% to 12.5% of the value obtained at three minutes after injection are noted and the mean half-life and standard deviation, expressing the microspheres blood clearance, is calculated. To determine the possibly non-linear nature of albumin microspheres clearance over time the area under the curve will be calculated over the observation time using integral function. Mean half-life of albumin microspheres in the blood and area under the curve at day 1 and day 7 after transplantation will be expressed as a percentage of preoperative values and compared between individuals and patient groups. We hypothesize that the phagocytosis activity of marginal compared to good liver grafts is significantly impaired after liver transplantation due to the decreased number of phagocytes as well as due to the decreased synthesis of substances which usually facilitates phagocytosis. If this hypothesis is true, the RES phagocytosis activity in the marginal grafts should be significantly increased after liver transplantation and should be comparable to the RES phagocytosis activity of non-marginal grafts.