Effect of surgical injury and intraoperative hypothermia on whole body protein metabolism

Whole body protein turnover and urinary nitrogen and 3-methyl-L-histidine (3-MH) excretion were measured before and after cardiac surgery using cardiopulmonary bypass in 20 male patients randomized to an intraoperative blood temperature of 28 or 20 degrees C. Rates of whole body protein synthesis (WBPS) and breakdown (WBPB) were determined from the 15N isotopic enrichment of urinary urea, ammonium, and from a calculated end-product average (EPA) after a primed 24-h infusion of [15N]glycine. In the postoperative period, there was a 40% increase in median nitrogen excretion in the 28 degrees C group (P less than 0.03) and a 22% increase in the 20 degrees C group (P = 0.10). There was a 79% increase in the median postoperative 3-MH excretion in the 28 degrees C group (P = 0.01) and a 66% increase in the median postoperative 3-MH excretion in the 20 degrees C group (P less than 0.01). Postoperatively, there was a 23% fall in the median value of WBPS in the 28 degrees C group (P less than 0.01) and an 11% fall in the 20 degrees C group [not significant (NS)] measured by 15N enrichment of urinary urea. In contrast, when WBPS was measured from isotopic enrichment of urinary ammonium, there was an increase in the median value of the postoperative rates of WBPS in both groups, by 20% in the 28 degrees C group (P = NS) and 29% in the 20 degrees C group (P = 0.03). There was no significant change in the rate of WBPS and WBPB, judged by the postoperative EPA in either group.(ABSTRACT TRUNCATED AT 250 WORDS

Influence of intrinsic variation on foraging behaviour of adult female Australian fur seals

Phenotypic variation and individual experience can create behavioural and/or dietary variation within a population. This may reduce intra-specific competition, creating a buffer to environmental change. This study examined how intrinsic variation affects foraging behaviour of Australian fur seals. Foraging movements of 29 female Australian fur seals were recorded using FastLoc GPS and dive behaviour recorders. For each individual, body mass, flipper length and axis length were recorded, a tooth was sampled to determine age, and milk was collected for diet analysis. Clustering of fatty acid dietary analysis revealed 5 distinct groups in the population. Behaviour was described using 19 indices, which were then reduced to 7 principal components (>80% of the behavioural variation). Bayesian mixed effect models were developed to describe the relationship between these components and intrinsic variation. No association was found between diet and age or body shape; however, age had a negative relationship with component 1 (27% of variation). Older females spent less time at-sea and foraged nearer to the colony. Age had an effect on component 5 (7% of variation), which represented haul-outs and dive depth; older females made fewer visits to haul-out sites and dived deeper to the benthos. This suggests that as animals age they are able to utilise prior knowledge to exploit nearby foraging sites that younger animals are either unaware of, or have yet to gain the experience required to efficiently utilise. Mass had a negative effect on components representing the directedness of a foraging trip, suggesting heavier individuals were more likely to travel directly to a foraging site

Resting and total energy expenditure in patients with ischemic heart disease

Total energy expenditure (TEE) was measured by doubly labeled water in 13 preoperative patients undergoing elective coronary artery surgery and compared to resting energy expenditure (REE) measured by indirect calorimetry (IC) calculated from the Harris-Benedict (HB) formula or from formulas based on midarm circumference and arm muscle circumference. Mean REE measured by IC and calculated from the HB, midarm circumference, arm muscle circumference formulas were 62, 75, 62, and 69%, respectively, of TEE measured by doubly labeled water. REE measured by IC correlated significantly with that predicted by the HB (p = 0.006) but not the anthropometric formulas. The relationship between REE derived from anthropometric predictive formulas and REE measured by IC is altered in ischemic heart disease