Objective Parenteral nutrition has been associated with metabolic and infectious complications in intensive care unit patients. The underlying mechanism for the high risk of complications is not known but may relate to the proinflammatory effects of soybean oil–based lipid emulsions, the only Food and Drug Administration–approved lipid formulation for clinical use. Design Prospective, double-blind, randomized, controlled trial. Setting Medical–surgical intensive care units from a major urban teaching hospital and a tertiary referral university hospital. Patients Adult medical–surgical intensive care unit patients. Intervention Parenteral nutrition containing soybean oil–based (Intralipid) or olive oil–based (ClinOleic) lipid emulsions. Measurements Differences in hospital clinical outcomes (nosocomial infections and noninfectious complications), hospital length of stay, glycemic control, inflammatory and oxidative stress markers, and granulocyte and monocyte functions between study groups. Results A total of 100 patients were randomized to either soybean oil–based parenteral nutrition or olive oil–based parenteral nutrition for up to 28 days. A total of 49 patients received soybean oil–based parenteral nutrition (age 51 ± 15 yrs, body mass index 27 ± 6 kg/m2, and Acute Physiology and Chronic Health Evaluation II score 15.5 ± 7 [±SD]), and a total of 51 patients received olive oil–based lipid emulsion in parenteral nutrition (age 46 ± 19 yrs, body mass index 27 ± 8 kg/m2, and Acute Physiology and Chronic Health Evaluation II score 15.1 ± 6 [±SD]) for a mean duration of 12.9 ± 8 days. The mean hospital blood glucose concentration during parenteral nutrition was 129 ± 14 mg/dL, without differences between groups. Patients treated with soybean oil–based and olive oil–based parenteral nutrition had a similar length of stay (47 ± 47 days and 41 ± 36 days, p = .49), mortality (16.3% and 9.8%, p = .38), nosocomial infections (43% vs. 57%, p = .16), and acute renal failure (26% vs. 18%, p = .34). In addition, there were no differences in inflammatory and oxidative stress markers or in granulocyte and monocyte functions between groups. Conclusion The administration of parenteral nutrition containing soybean oil–based and olive oil–based lipid emulsion resulted in similar rates of infectious and noninfectious complications and no differences in glycemic control, inflammatory and oxidative stress markers, and immune function in critically ill adults.

Genomic recombination requires cutting, processing, and rejoining of DNA by endonucleases, polymerases, and ligases, among other factors. We have proposed that DNA recombination mechanisms may contribute to long-term memory (LTM) formation in the brain. Our previous studies with the nucleoside analog 1-␤-D-arabinofuranosylcytosine triphosphate (ara-CTP), a known inhibitor of DNA ligases and polymerases, showed that this agent blocked consolidation of conditioned taste aversion without interfering with short-term memory (STM). However, because polymerases and ligases are also essential for DNA replication, it remained unclear whether the effects of this drug on consolidation were attributable to interference with DNA recombination or neurogenesis. Here we show, using C57BL/6 mice, that ara-CTP specifically blocks consolidation but not STM of context fear conditioning, a task previously shown not to require neurogenesis. The effects of a single systemic dose of cytosine arabinoside (ara-C) on LTM were evident as early as 6 h after training. In addition, although ara-C impaired LTM, it did not impair general locomotor activity nor induce brain neurotoxicity. Importantly, hippocampal, but not insular cortex, infusions of ara-C also blocked consolidation of context fear conditioning. Separate studies revealed that context fear conditioning training significantly induced nonhomologous DNA end joining activity indicative of DNA ligasedependent recombination in hippocampal, but not cortex, protein extracts. Finally, unlike inhibition of protein synthesis, systemic ara-C did not block reconsolidation of context fear conditioning. Our results support the idea that DNA recombination is a process specific to consolidation that is not involved in the postreactivation editing of memories.