Protein metabolism following injury.

Fig. 1 Comparisons in two burned patients between the rate of catabolism ofplasma albumin and y G globulin (as glkg body weight) and the basal metabolic rate (BMR) as percentages above the expected normal value. The patient treated in the cool environment had a burned area covering 30% of the body surface, 10% being full-thickness skin loss; the patient treated in the warm environment had a burned area covering 50% of the body surface, 25% being full-thickness skin loss. The expected normal range of catabolism ofalbumin lies between 015 and 0-20 g per kg, and that for y G globulin between 0.035 and 0.055 g per kg per day. by Kinney, 1962) have elucidated some of the complex mechanisms of this catabolic response. It appears to be dependent on the severity of injury (Moore and Ball, 1952; Cuthbertson and Tilstone, 1968); on the environmental temperature at which the experimental animals or injured patients are treated after injury (Caldwell, 1962; Campbell and Cuthbertson, 1967; Cuthbertson, Smith, and Tilstone, 1968; Davies, Liljedahl, and Birke, 1969); and on the state of protein nutrition before injury (Munro and Chalmers, 1945; Abbott and Albertsen, 1963). It is probably independent of an intact nervous pathway between the site of injury and the brain (Davies, Liljedahl, and Reizenstein, 1970b). In most patients with injuries other than burns there is a close correspondence between the increased rate of nitrogen excretion and the increase in the metabolic rate (Cairnie, Campbell, Pullar, and Cuthbertson, 1957; Kinney, 1962). A similar close correspondence has been observed in patients with extensive burns (Cope, Nardi, Quijano, Rovit, Stanbury, and Wight, 1953; Rabelo, Clark, and Kinney, 1961) and also between plasma albumin catabolism and nitrogen excretion in patients with burns and other injuries (Davies, Ricketts, and Bull, 1959). A less satisfactory correspondence (Fig. 1) has been found between plasma albumin and y G globulin catabolism and basal metabolic rate in patients with burns treated in different environmental temperatures (Davies et al, 1969). Studies of the catabolic response to injury have been considerably assisted by the development of methods for the isolation of single plasma proteins and their trace labelling with radioactive iodine (McFarlane, 1964). These methods of isolation and labelling do not alter the biological functions or survival of the proteins if they are carried out with considerable care (Cohen, Freeman, and McFarlane, 1961; McFarlane, 10