Current opinion in clinical nutrition and metabolic care
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Curr Opin Clin Nutr Metab Care · Jan 2007
ReviewPathophysiology of glutamine and glutamate metabolism in premature infants.
The potential efficacy of glutamine and glutamate as nutritional supplements for premature infants was originally met with enthusiasm. Despite no evidence of toxicity in the clinical trials, the use of glutamine has not become routine. In certain studies, the benefits seem clear, whereas in others, benefits have not been demonstrated. Specific designs for studies have been difficult, targets based on mechanistic frameworks have been poorly defined, study populations are heterogeneous and putative mechanisms of glutamine action are multifold. Our purpose is to review recent findings pertaining to (1) the action and mechanisms of glutamine and glutamate in the gastrointestinal tract, and (2) the future directions for glutamine and glutamate research with a focus on the premature neonate. ⋯ We review recent studies of mechanisms of glutamine and glutamate action, pertinent clinical trials, and suggest areas for future research based on these mechanisms.
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Curr Opin Clin Nutr Metab Care · Nov 2006
ReviewBiomarkers of oxidative stress in critically ill patients: what should be measured, when and how?
This review is dedicated to updating the knowledge on oxidative stress in critically ill patients with an intense inflammatory reaction, and to link it with recent findings supporting the possible involvement of oxidative injuries in systems and organs that frequently fail in the critically ill. ⋯ The assessment of oxidative stress, defined as the association between an increased production of oxygen-derived species and an exhaustion of the stores of antioxidants, requires a multimodal approach. Oxidative damage itself can be much better estimated by quantifying the oxidative byproducts of the lipids and proteins associated with an evaluation of the remaining stores of the corresponding functional antioxidants, or the activity of antioxidant enzymes, than by global tests of the total oxidative damage or the total antioxidant stores. Recent clinical data confirm an important role of increased oxidative stress in the acute dysfunctions of the respiratory, renal and cerebral systems.
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Curr Opin Clin Nutr Metab Care · Nov 2006
ReviewUpdate on clinical micronutrient supplementation studies in the critically ill.
During the past 2 years a number of studies, meta-analyses and reviews have shown that micronutrient supplementation may be beneficial in critical illness. Selenium is emerging as a particularly important micronutrient. This paper reviews the evidence from trials in the critically ill, putting mechanisms, methods and shortcomings into perspective. ⋯ Plasma micronutrient concentrations are low during critical illness, as a result of losses, low intakes and dilution, and redistribution from plasma to tissues. An assessment of status is difficult. Micronutrient supplements appear beneficial in conditions such as major burns, trauma and sepsis and stroke, and are most likely to benefit patients with previous or actual depletion. The intravenous route seems more efficient than the enteral. Although chronic high intakes may be harmful, short-term interventions appear to be free of deleterious effects. Further research is required to determine the optimal micronutrient combinations and the doses required according to the timing of intervention and severity of disease.
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Curr Opin Clin Nutr Metab Care · Sep 2006
Review6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase and tumor cell glycolysis.
Neoplastic cells metabolize abundant glucose relative to normal cells in order to satisfy the increased energetic and anabolic needs of the transformed state. This review will summarize the requirement of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases for the regulation of glycolysis in cancer cells and their potential utility as targets for the development of antineoplastic agents. ⋯ These findings demonstrate a key role for the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases in neoplastic transformation and provide rationale for the development of agents that selectively inhibit the PFKFB3 enzyme as antineoplastic agents.
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Curr Opin Clin Nutr Metab Care · Sep 2006
ReviewGlutamine: role in gut protection in critical illness.
Recent literature has focused on the role of the gut and increased gut permeability as a driver of systemic inflammation in critical illness. Thus, the therapeutic potential for an agent to prevent gut barrier compromise and attenuate gut-derived inflammatory response is significant. ⋯ These mechanistic findings, combined with a limited amount of clinical data showing benefit on gut permeability in illness and injury, indicate more formal studies need to be carried out looking the role of glutamine in gut protection and as an antiinflammatory in critical illness.